Digital Controller for Isolated
Power Supply with PMBus Interface
Data Sheet
ADP1051
FEATURES
Versatile digital voltage mode controller
High speed input voltage feedforward control
6 pulse-width modulation (PWM) logic outputs with 625 ps
resolution
Switching frequency: 49 kHz to 625 kHz
Frequency synchronization as master and slave device
Multiple energy saving modes
Adaptive dead time compensation for efficiency optimization
Low device power consumption: 100 mW typical
Direct parallel control for power supplies without OR’ing devices
Accurate droop current share
Pre-bias startup
Reverse current protection
Conditional overvoltage protection
Extensive fault detection and protection
PMBus compliant
Graphical user interface (GUI) for ease of programming
On-board EEPROM for programming and data storage
Available in a 24-lead, 4 mm × 4 mm LFCSP
−40°C to +125°C operating temperature
APPLICATIONS
High density isolated dc-to-dc power supplies
Intermediate bus converters
High availability parallel power systems
Server, storage, industrial, networking, and communications
infrastructure
GENERAL DESCRIPTION
The ADP1051 is an advanced digital controller with a PMBusTM
interface targeting high density, high efficiency dc-to-dc power
conversion. This controller implements voltage mode control with
high speed, input line feedforward for enhanced transient and
improved noise performance. The ADP1051 has six programmable
pulse-width modulation (PWM) outputs capable of controlling
most high efficiency power supply topologies, with added control
of synchronous rectification (SR). The device includes adaptive
dead time compensation to improve efficiency over the load range,
and programmable light load mode operation, combined with
low power consumption, to reduce system standby power losses.
The ADP1051 implements several features to enable a robust
system of parallel and redundant operation for customers that
require high availability or parallel connection. The device provides
synchronization, reverse current protection, pre-bias startup,
accurate current sharing between power supplies, and conditional
overvoltage techniques to identify and safely shut down an
erroneous power supply in parallel operation mode.
The ADP1051 is based on flexible state machine architecture
and is programmed using an intuitive GUI. The easy to use
interface reduces design cycle time and results in a robust,
hardware coded system loaded into the built-in EEPROM. The
small size (4 mm × 4 mm) LFCSP package makes the ADP1051
ideal for ultracompact, isolated dc-to-dc power module or
embedded power designs.
TYPICAL APPLICATIONS CIRCUIT
RES RTDADD VCORE PG/ALTCTRL SDA SCL AGND
OUTA
OUTB
OUTC
OUTD
CS1 SR1 SR2 VF OVP
SYNI/FLGI
VDD
DRIVER
DRIVER
LOAD
VS+
DC
INPUT
PMBus
CS2– CS2+ VS–
ADP1051
Coupler
®
i
11443-001
Figure 1.
Rev. A Document Feedback
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ADP1051 Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
General Description ......................................................................... 1
Typical Applications Circuit ............................................................ 1
Revision History ............................................................................... 3
Specifications ..................................................................................... 4
Absolute Maximum Ratings ............................................................ 9
Thermal Resistance ...................................................................... 9
Soldering ........................................................................................ 9
ESD Caution .................................................................................. 9
Pin Configuration and Function Descriptions ........................... 10
Typical Performance Characteristics ........................................... 12
Theory of Operation ...................................................................... 14
PWM Outputs (OUTA, OUTB, OUTC, OUTD, SR1, and
SR2) .............................................................................................. 15
Synchronous Rectification ........................................................ 15
PWM Modulation Limit and 180° Phase Shift ....................... 16
Adaptive Dead Time Compensation (ADTC) ....................... 16
Light Load Mode and Deep Light Load Mode ....................... 17
Frequency Synchronization ...................................................... 17
Output Voltage Sense and Adjustment .................................... 19
Digital Compensator .................................................................. 21
Closed-Loop Input Voltage Feedforward Control and
VF Sense ...................................................................................... 21
Open-Loop Input Voltage Feedforward Operation ............... 22
Open-Loop Operation ............................................................... 23
Current Sense .............................................................................. 23
Soft Start and Shutdown ............................................................ 24
Volt-Second Balance Control .................................................... 26
Constant Current Mode ............................................................ 27
Pulse Skipping ............................................................................. 27
Pre-Bias Startup .......................................................................... 27
Output Voltage Drooping Control ........................................... 28
VDD and VCORE ...................................................................... 28
Chip Password ............................................................................ 28
Power Monitoring, Flags, and Fault Responses .......................... 29
Flags .............................................................................................. 29
Voltage Readings ........................................................................ 32
Current Readings ........................................................................ 32
Power Readings ........................................................................... 32
Duty Cycle Reading ................................................................... 33
Switching Frequency Reading .................................................. 33
Temperature Reading ................................................................. 33
Temperature Linearization Scheme ......................................... 34
PMBus Protection Commands ................................................. 34
Manufacturer Specific Protection Commands ....................... 36
Manufacturer Specific Protection Responses ......................... 39
Power Supply Calibration and Trim ............................................ 40
IIN Trim (CS1 Trim).................................................................... 40
IOUT Trim (CS2 Trim) ................................................................. 40
VOUT Trim (VS Trim) ................................................................. 40
VIN Trim (VF Gain Trim) .......................................................... 41
RTD and OTP Trim ................................................................... 41
Applications Configurations ......................................................... 42
Layout Guidelines ........................................................................... 43
CS1 Pin ........................................................................................ 43
CS2+ and CS2− Pins .................................................................. 43
VS+ and VS− Pins ...................................................................... 43
OUTA to OUTD, SR1 AND SR2 PWM Outputs .................. 43
VDD Pin ...................................................................................... 43
VCORE Pin ................................................................................. 43
RES Pin ........................................................................................ 43
SDA and SCL Pin ....................................................................... 43
Exposed Pad ................................................................................ 43
RTD Pin ....................................................................................... 43
AGND Pin ................................................................................... 43
PMBus/I2C Communication ......................................................... 44
PMBus Features .......................................................................... 44
Overview ..................................................................................... 44
PMBus/I2C Address ................................................................... 44
Data Transfer............................................................................... 44
General Call Support ................................................................. 46
10-Bit Addressing ....................................................................... 46
Fast Mode .................................................................................... 46
Fault Conditions ......................................................................... 46
Timeout Conditions ................................................................... 46
Data Transmission Faults .......................................................... 46
Data Content Faults ................................................................... 47
EEPROM ......................................................................................... 48
EEPROM Features ...................................................................... 48
Rev. A | Page 2 of 108
Data Sheet ADP1051
EEPROM Overview .................................................................... 48
Page Erase Operation ................................................................. 48
Read Operation (Byte Read and Block Read) ......................... 48
Write Operation (Byte Write and Block Write) ...................... 49
EEPROM Password..................................................................... 49
Downloading EEPROM Settings to Internal Registers .......... 50
Saving Register Settings to the EEPROM ................................ 50
EEPROM CRC Checksum ......................................................... 50
GUI Software ................................................................................... 51
PMBus Command Set .................................................................... 52
Manufacturer Specific Extended Command List ....................... 55
PMBus Command Descriptions ................................................... 58
Basic PMBus Commands ........................................................... 58
Manufacturer Specific Extended Commands Descriptions ...... 77
Flag Configuration Registers ..................................................... 77
Soft Start and Software Reset Registers .................................... 79
Blanking and PGOOD Setting Registers ................................. 80
Switching Frequency and Synchronization Registers ............ 82
Current Sense and Limit Setting Registers .............................. 83
Voltage Sense and Limit Setting Registers ............................... 88
Temperature Sense and Protection Setting Registers ............. 89
Digital Compensator and Modulation Setting Registers ....... 90
PWM Outputs Timing Registers .............................................. 93
Volt-Second Balance Control Registers ................................... 95
Duty Cycle Reading Setting Registers ...................................... 96
Adaptive Dead Time Compensation Registers ....................... 97
Other Register Settings............................................................. 100
Manufacturer Specific Fault Flag Registers ........................... 104
Manufacturer Specific Valu e Reading Registers ................... 106
Outline Dimensions ...................................................................... 108
Ordering Guide ......................................................................... 108
REVISION HISTORY
6/14—Rev. 0 to Rev. A
Changes to Table 1 ............................................................................ 4
Changes to Table 2 ............................................................................ 9
Changes to Pin 24, Table 4 ............................................................. 11
Changes to Frequency Synchronization Section ......................... 18
Changes to Figure 28 ...................................................................... 24
Changes to VOUT_COMMAND Section ................................... 60
Changes to Ordering Guide .........................................................108
7/13—Revision 0: Initial Version
Rev. A | Page 3 of 108
ADP1051 Data Sheet
SPECIFICATIONS
VDD = 3.0 V to 3.6 V, TJ = −40°C to +125°C, unless otherwise noted. FSR = full-scale range.
Table 1.
Parameter Symbol Min Typ Max Unit Test Conditions/Comments
SUPPLY
Supply Voltage VDD 3.0 3.3 3.6 V 2.2 μF capacitor connected to AGND
Supply Current IDD 28.5 33 mA Normal operation; PWM pins unloaded
IDD + 6 mA During EEPROM programming
50 100 μA Shutdown; VDD below undervoltage
lockout (UVLO)
POWER-ON RESET
Power-On Reset 3.0 V VDD rising
UVLO Threshold 2.75 2.85 2.97 V VDD falling
UVLO Hysteresis
35
OVLO Threshold 3.7 3.9 4.1 V
OVLO Debounce 2 μs VDD_OV flag debounce set to 2 μs
500 μs VDD_OV flag debounce set to 500 μs
VCORE PIN
Output Voltage VCORE 2.45 2.6 2.75 V 330 nF capacitor connected to AGND
OSCILLATOR AND PLL
PLL Frequency 190 200 210 MHz RES input = 10 kΩ (±0.1%)
Digital PWM Resolution 625 ps
OUTA, OUTB, OUTC, OUTD, SR1, SR2 PINS
Output Low Voltage VOL 0.4 V IOH = +10 mA
Output High Voltage VOH VDD − 0.4 V IOL = −10 mA
Rise Time tR 3.5 ns CLOAD = 50 pF
Fall Time tF 1.5 ns CLOAD = 50 pF
Output Source Current
I
OL
−10
Output Sink Current IOH 10 mA
Synchronization Signal Output (SYNO)
Positive Pulse Width
600 640 680 ns OUTC or OUTD programmed as SYNO
VS+, VS− VOLTAGE SENSE PINS
Input Voltage Range VIN 0 1 1.6 V Differential voltage from VS+ to VS−
Leakage Current 1.0 μA
VS Accurate ADC
Valid Input Voltage Range 0 1.6 V
ADC Clock Frequency 1.56 MHz
Register Update Rate 10 ms
Measurement Resolution 12 Bits
Measurement Accuracy Factory trimmed at 1.0 V
−5 +5 % FSR 0% to 100% of input voltage range
−80
+80
−2 +2 % FSR 10% to 90% of input voltage range
−32 +32 mV
−1.0 +1.0 % FSR 900 mV to 1.1 V
−16 +16 mV
Temperature Coefficient 70 ppm/°C
Voltage Differential from VS− to AGND −200 +200 mV
VS High Speed ADC
Equivalent Sampling Frequency fSAMP fSW kHz
Equivalent Resolution 6 Bits fSW = 390.5 kHz
Dynamic Range ±25 mV Regulation voltage = 0 mV to 1.6 V
Rev. A | Page 4 of 108
Data Sheet ADP1051
Parameter Symbol Min Typ Max Unit Test Conditions/Comments
VS UVP Digital Comparator Triggers VOUT_UV_FAULT flag
Threshold Accuracy −2 +2 % FSR 10% to 90% of input voltage range
Comparator Update Speed 82 µs
OVP PIN Triggers VOUT_OV_FAULT flag
Leakage Current 1.0 µA
OVP Comparator
Voltage Range 0.75 1.5 V Differential voltage from OVP to VS−
Threshold Accuracy
−1.6
1
+1.6
0.75 V to 1.5 V voltage range
Propagation Delay (Latency) 61 85 ns Debounce time not included
VF VOLTAGE SENSE PIN
Input Voltage Range
V
IN
0
1
1.6
Voltage from VF to AGND
Leakage Current 1.0 µA
General ADC
Valid Input Voltage Range 0 1.6 V
ADC Clock Frequency 1.56 MHz
Register Update Rate 1.31 ms
Measurement Resolution 11 Bits
Measurement Accuracy −2 +2 % FSR 10% to 90% of input voltage range
−32 +32 mV
−5 +5 % FSR 0% to 100% of input voltage range
−80 +80 mV
VF UVP Digital Comparator
Triggers VIN_LOW or VIN_UV_FAULT flag
Threshold Accuracy Based on VF general ADC parameter
values
Comparator Update Speed 1.31 ms
Feedforward ADC
Input Voltage Range VIN 0.5 1 1.6 V
Resolution 11 Bits
Sampling Period 10 μs
CS1 CURRENT SENSE PIN
Input Voltage Range VIN 0 1 1.6 V Voltage from CS1 to AGND
Source Current −1.2 −0.35 µA
CS1 ADC
Valid Input Voltage Range 0 1.6 V
ADC Clock Frequency 1.56 MHz
Register Update Rate
10
Measurement Resolution 12 Bits
Measurement Accuracy −2 +2 % FSR 10% to 90% of input voltage range
−32 +32 mV
−5 +5 % FSR 0% to 100% of input voltage range
−80 +80 mV
CS1 OCP Comparator Triggers internal CS1_OCP flag
Reference Accuracy 1.185 1.2 1.215 V When set to 1.2 V
0.235 0.25 0.265 V When set to 0.25 V
Propagation Delay (Latency) 65 105 ns Debounce/blanking time not included
CS31 Measurement and Digital
Comparator
Triggers CS3_OC_FAULT flag
Register Update Rate 10 ms
Comparator Speed 10 ms
Rev. A | Page 5 of 108
ADP1051 Data Sheet
Parameter Symbol Min Typ Max Unit Test Conditions/Comments
CS2+, CS2− CURRENT SENSE PINS
Input Voltage Range VIN 0 120 mV Differential voltage from CS2+ to CS2−
Common-Mode Voltage at CS2+ and CS2− 0.8 1.15 1.4 V To achieve CS2 measurement accuracy
Current Sink (High Side) 1.87 1.915 1.96 mA
Current Source (Low Side)
195
225
255
Temperature Coefficient 95 ppm/°C
CS2 ADC
Valid Input Voltage Range 0 120 mV
ADC Clock Frequency 1.56 MHz
Measurement Resolution 12 Bits
Low-Side Mode Current Measurement
Sense Accuracy
4.99 kΩ (0.01%) level shift resistors
−1.9 +1.9 % FSR From 0 mV to 110 mV
−2.28 +2.28 mV
−6.1 +1.4 % FSR From 110 mV to 120 mV
−7.32 +1.68 mV
High-Side Mode Current Measurement
Sense Accuracy
CS2 high-side factory trim values loaded;
4.99 kΩ (0.01%) level shift resistors;
VOUT = 11 V
−1.6 +2.3 % FSR From 0 mV to 110 mV
−1.92 +2.76 mV
−5.3
+0.7
From 110 mV to 120 mV
−6.36 +0.84 mV
CS2 OCP Digital Comparator Triggers IOUT_OC_FAULT flag
Threshold Accuracy Same as CS2 ADC low-side and high-side
mode current measurement sense
accuracy values
Comparator Update Speed 82 µs When set to the 7-bit averaging speed
328 µs When set to the 9-bit averaging speed
CS2 Reverse Current Comparator Triggers SR_RC_FAULT flag
Threshold Accuracy −8.5 −3 +3 mV SR_RC_FAULT_LIMIT set to −3 mV
−11.5 −6 0 mV SR_RC_FAULT_LIMIT set to −6 mV
−14
−9
−3
SR_RC_FAULT_LIMIT set to −9 mV
−17 −12 −6 mV SR_RC_FAULT_LIMIT set to −12 mV
−21 −15 −9 mV SR_RC_FAULT_LIMIT set to −15 mV
−24 −18 −12 mV SR_RC_FAULT_LIMIT set to −18 mV
−27 −21 −15 mV SR_RC_FAULT_LIMIT set to −21 mV
−30 −24 −18 mV SR_RC_FAULT_LIMIT set to −24 mV
Propagation Delay
110
150
Debounce time = 40 ns
RTD TEMPERATURE SENSE PIN
Input Voltage Range VIN 0 1.6 V Voltage from RTD to AGND
Source Current 44.6 46 47.3 μA Register 0xFE2D = 0xE6, factory default
setting
38.6 40 42 μA Register 0xFE2D = 0xB0
28.6 30 31.8 μA Register 0xFE2D = 0x80
18.6 20 21.6 μA Register 0xFE2D = 0x40
9.1 10 11 μA Register 0xFE2D = 0x00
RTD ADC
Valid Input Voltage Range 0 1.6 V
ADC Clock Frequency 1.56 MHz
Register Update Rate 10 ms
Measurement Resolution 12 Bits
Rev. A | Page 6 of 108
Data Sheet ADP1051
Parameter Symbol Min Typ Max Unit Test Conditions/Comments
Measurement Accuracy −0.3 +0.45 % FSR 2% to 20% of the input voltage range
−4.8 +7.2 mV
−2 +2 % FSR 0% to 100% of the input voltage range
−80 +80 mV
OTP Digital Comparator
Triggers OT_FAULT flag
Threshold Accuracy −0.9 +0.25 % FSR T = 85°C with 100 kΩ||16.5 kΩ
−14.4 +4 mV
−0.5 +1.1 % FSR T = 100°C with 100 kΩ||16.5 kΩ
−8 +17.6 mV
Comparator Update Speed 10 ms
Temperature Readings According to
Internal Linearization Scheme
Source current is set to
46 µA
(Register 0xFE2D = 0xE6); NTC R25 = 100 kΩ
(1%); beta = 4250 (1%); REXT = 16.5 kΩ (1%)
7 °C 25°C to 100°C
5 °C 100°C to 125°C
PG/ALT (OPEN-DRAIN) PIN
Output Low Level VOL 0.4 V Sink current = 10 mA
CTRL PIN
Input Low Level VIL 0.4 V
Input High Level VIH VDD − 0.8 V
Leakage Current 1.0 µA
SYNI/FLGI PINS
Input Low Level VIL 0.4 V
Input High Level VIH VDD − 0.8 V
Synchronization Range % of Internal Clock
Period
t
SYNC
90
110
SYNI Positive Pulse Width 360 ns External clock applied on SYNI/FLGI pin
SYNI Negative Pulse Width 360 ns External clock applied on SYNI/FLGI pin
SYNI Period Drift 280 ns Period drift between two consecutive
external clocks
Leakage Current 1.0 µA
SDA, SCL PINS
Input Voltage Low
V
IL
0.8
Input Voltage High VIH VDD − 0.8 V
Output Voltage Low VOL 0.4 V Sink current = 3 mA
Leakage Current −5 +5 µA
SERIAL BUS TIMING See Figure 2
Clock Operating Frequency 10 100 400 kHz
Glitch Immunity 50 ns
Bus Free Time tBUF 1.3 µs Between stop and start conditions
Start Setup Time tSU;STA 0.6 µs Repeated start condition setup time
Start Hold Time
t
HD;STA
0.6
Hold time after (repeated) start condition;
after this period, the first clock is
generated
Stop Setup Time tSU;STO 0.6 µs
SDA Setup Time tSU; DAT 100 ns
SDA Hold Time tHD;DAT 125 ns For readback
300 ns For write
SCL Low Timeout tTIMEOUT 25 35 ms
SCL Low Time tLOW 0.6 µs
SCL High Time tHIGH 0.6 µs
SCL Low Extend Time tLOW;SEXT 25 ms
SCL, SDA Rise Time
t
R
20
300
SCL, SDA Fall Time tF 20 300 ns
Rev. A | Page 7 of 108
ADP1051 Data Sheet
Parameter Symbol Min Typ Max Unit Test Conditions/Comments
EEPROM
EEPROM Update Time 40 ms Time from the update command to
completion of the EEPROM update
Reliability
Endurance2 10,000 Cycles TJ = 85°C
1000 Cycles TJ = 125°C
Data Retention3 20 Years TJ = 85°C
15 Years TJ = 125°C
1 CS3 is an alternative output current reading that is calculated by the CS1 reading (representing input current), duty cycle, and main transformer turn ratio.
2 Endurance is qualified as per JEDEC Standard 22, Method A117, and is measured at −40°C, +25°C, +85°C, and +125°C.
3 Retention lifetime equivalent at junction temperature as per JEDEC Standard 22, Method A117.
Timing Diagram
SCL
SDA
P S
t
BUF
t
HD;STA
t
HD;DAT
t
HIGH
t
SU;DAT
t
HD;STA
t
SU;STA
t
SU;STO
t
LOW
t
R
t
F
S P
11443-002
Figure 2. Serial Bus Timing Diagram
Rev. A | Page 8 of 108
Data Sheet ADP1051
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
Supply Voltage (Continuous) VDD to AGND 4.2 V
Digital Pins (OUTA, OUTB, OUTC, OUTD,
SR1, SR2, PG/ALT, SDA, SCL) to AGND
−0.3 V to VDD + 0.3 V
PG/ALT, SDA, SCL to AGND −0.3 V to +3.9 V
VS−, VS+, VF, OVP, RTD, ADD, CS1, CS2+, CS2−
to AGND
−0.3 V to VDD + 0.3 V
SYNI/FLGI, CTRL to AGND −0.3 V to VDD + 0.3 V
Operating Temperature Range (T
A
)
−40°C to +125°C
Storage Temperature Range −65°C to +150°C
Junction Temperature 150°C
Peak Solder Reflow Temperature
SnPb Assemblies (10 sec to 30 sec) 240°C
RoHS-Compliant Assemblies (20 sec to
40 sec)
260°C
ESD Charged Device Model 1.25 kV
ESD Human Body Model 5.0 kV
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
THERMAL RESISTANCE
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Table 3. Thermal Resistance
Package Type θJA θJC Unit
24-Lead LFCSP 36.26 1.51 °C/W
SOLDERING
It is important to follow the correct guidelines when laying out
the printed circuit board (PCB) footprint for the ADP1051 and
for soldering the part onto the PCB. For detailed information
about these guidelines, see the AN-772 Application Note, A Design
and Manufacturing Guide for the Lead Frame Chip Scale Package
(LFCSP).
ESD CAUTION
Rev. A | Page 9 of 108
ADP1051 Data Sheet
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
2
1
3
4
5
6
18
17
16
15
14
13
CS1
VF
CS2+
CS2–
VS+
VS–
SYNI/FLGI
SCL
SDA
CTRL
PG/ALT
VCORE
NOTES
1. F OR I NCRE AS E D RE LIABIL ITY OF THE SOLDER
JOINTSAND MAX IMUM THERM AL CAPABILITY,
IT IS RECOMMENDED THAT THE EXPOSED PAD
BE SOLDERED TO T HE P CB AGND P LANE.
8
9
10
11
7
SR2
OUTA
OUTB
OUTC
12
OUTD
SR1
20
19
21
AGND
VDD
RES
22 ADD
23 RTD
24 OVP
ADP1051
TOP VIEW
11443-003
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1 VS− Inverting Voltage Sense Input. This is the connection for the ground line of the power rail. Provide a low ohmic
connection to AGND. To allow for trimming, it is recommended that the resistor divider on this input have
a tolerance specification of ≤0.5%.
2 VS+ Noninverting Voltage Sense Input. This signal is referred to VS−. To allow for trimming, it is recommended that the
resistor divider on this input have a tolerance specification of ≤0.5%.
3
CS2−
Inverting Differential Current Sense Input. For best operation, use a nominal voltage of 1.12 V. When using low-
side current sensing, place a 4.99 kΩ level shifting resistor between the sense resistor and this pin. When using
high-side current sensing in a 12 V application, place a 5.62 kΩ resistor between the sense resistor and this pin.
When using high-side current sensing, apply the formula R = (VOUT − 1.12 V)/1.915 mA. A 0.1% resistor must be
used to connect this circuit. If this pin is not used, connect it to AGND and set the CS2 current sense to high-side
current sense mode (Register 0xFE19[7] = 1 binary).
4 CS2+ Noninverting Differential Current Sense Input. For best operation, use a nominal voltage of 1.12 V. When using
low-side current sensing, place a 4.99 kΩ level shifting resistor between the sense resistor and this pin. When
using high-side current sensing in a 12 V application, place a 5.62 kΩ resistor between the sense resistor and this
pin. When using high-side current sensing, apply the formula R = (VOUT − 1.12 V)/1.915 mA. A 0.1% resistor must
be used to connect this circuit. If this pin is not used, connect it to AGND and set the CS2 current sense to high-
side current sense mode (Register 0xFE19[7] = 1 binary).
5 VF Three optional functions can be implemented with this pin: feedforward, primary side input voltage sensing, and
input voltage UVLO protection. The pin is connected upstream of the output inductor through a resistor divider
network. The nominal voltage at this pin should be 1 V. This signal is referred to AGND.
6 CS1 Primary Side Current Sense Input. This pin is connected to the primary side current sensing ADC and to the cycle-
by-cycle current-limit comparator. This signal is referred to AGND. The resistors on this input must have a
tolerance specification of ≤0.5% to allow for trimming. Connect this pin to AGND if not in use.
7 SR1 PWM Logic Output Drive. This pin can be disabled when not in use. This signal is referred to AGND.
8 SR2 PWM Logic Output Drive. This pin can be disabled when not in use. This signal is referred to AGND.
9 OUTA PWM Logic Output Drive. This pin can be disabled when not in use. This signal is referred to AGND.
10 OUTB PWM Logic Output Drive. This pin can be disabled when not in use. This signal is referred to AGND.
11
OUTC
PWM Logic Output Drive. This pin can be disabled when not in use. This signal is referred to AGND. This pin can
also be programmed as a synchronization signal output (SYNO).
12 OUTD PWM Logic Output Drive. This pin can be disabled when not in use. This signal is referred to AGND. This pin can
also be programmed as a synchronization signal output (SYNO).
13 SYNI/FLGI Synchronization Signal Input (SYNI)/External Signal Input to Generate a Flag Condition (FLGI). Connect this pin to
AGND if not in use.
14
SCL
I
2
C/PMBus Serial Clock Input and Output (Open Drain). This signal is referred to AGND.
15 SDA I2C/PMBus Serial Data Input and Output (Open Drain). This signal is referred to AGND.
16 CTRL PMBus Control Signal. It is recommended that a 1 nF capacitor be connected from the CTRL pin to AGND for noise
debounce and decoupling. This signal is referred to AGND.
Rev. A | Page 10 of 108
Data Sheet ADP1051
Pin No. Mnemonic Description
17 PG/ALT Power Good Output (Open Drain). Connect this pin to VDD through a pull-up resistor (typically 2.2 kΩ).This signal
is referred to AGND. This pin is also used as an SMBus ALERT signal. (For information about the SMBus specification,
see the PMBUS Features section.)
18 VCORE Output of 2.6 V Regulator. Connect a decoupling capacitor of at least 330 nF from this pin to AGND, as close as
possible to the ADP1051, minimizing the PCB trace length. It is recommended that this pin not be used as a
reference or to generate other logic levels using resistive dividers.
19 VDD Positive Supply Input. Voltage of 3.0 V to 3.6 V. This signal is referred to AGND. Connect a 2.2 μF decoupling
capacitor from this pin to the AGND, as close as possible to the ADP1051, minimizing the PCB trace length.
20 AGND Common Analog Ground. The internal analog circuitry ground and digital circuitry ground is star connected to
this pin through bonding wires.
21
RES
Resistor Input. This pin sets up the internal reference for the internal PLL frequency. Connect a 10 kΩ resistor
(±0.1%) from this pin to AGND. This signal is referred to AGND.
22 ADD Address Select Input. This pin is used to program the I2C/PMBus address. Connect a resistor from ADD to AGND.
This signal is referred to AGND.
23 RTD Thermistor Input. Place a thermistor (R25 = 100 kΩ (1%), beta = 4250 (1%)) in parallel with a 16.5 kΩ (1%) resistor
and a 1 nF filtering capacitor. This pin is referred to AGND. Connect this pin to AGND if not in use.
24 OVP Overvoltage Protection. This signal is used as redundant overvoltage protection. This signal is referred to AGND.
EP Exposed Pad. The ADP1051 has an exposed thermal pad on the underside of the package. For increased reliability
of the solder joints and maximum thermal capability, it is recommended that the exposed pad be soldered to the
PCB AGND plane.
Rev. A | Page 11 of 108
ADP1051 Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
VS ADC ACCURACY (%FSR)
–60 –40 –20 020 40
TEMPERATURE (°C)
60 80 100 120 140
MAX SPEC
MIN SPEC
MAX
MEAN
MIN
11443-007
2.5
2.0
1.5
0.5
–0.5
1.0
0
–1.0
–1.5
–2.0
–2.5
Figure 4. VS ADC Accuracy vs. Temperature (From 10% to 90% of FSR)
VF ADC ACCURACY (%FSR)
–60 –40 –20 020 40
TEMPERATURE (°C)
60 80 100 120 140
MAX SPEC
MIN SPEC
MAX
MEAN
MIN
11443-008
2.5
2.0
1.5
0.5
–0.5
1.0
0
–1.0
–1.5
–2.0
–2.5
Figure 5. VF ADC Accuracy vs. Temperature (From 10% to 90% of FSR)
CS1 ADC ACCURACY (%F S R)
–60 –40 –20 020 40
TEMPERATURE (°C)
60 80 100 120 140
MAX SPEC
MIN SPEC
MAX
MEAN
MIN
11443-009
2.5
2.0
1.5
0.5
–0.5
1.0
0
–1.0
–1.5
–2.0
–2.5
Figure 6. CS1 ADC Accuracy vs. Temperature (From 10%to 90% of FSR)
CS2 ADC ACCURACY (%F S R)
–60 –40 –20 020 40
TEMPERATURE (°C)
60 80 100 120 140
MAX SPEC
MIN SPEC
MIN
11443-010
2.5
2.0
1.5
0.5
–0.5
1.0
0
–1.0
–1.5
–2.0
–2.5
MEAN MAX
Figure 7. CS2 ADC Accuracy vs. Temperature (From 0 mV to 120 mV)
RTD ADC ACCURACY (%FSR)
–60 –40 –20 020 40
TEMPERATURE (°C)
60 80 100 120 140
MAX SPEC
MIN SPEC
MAX
MIN
11443-011
2.5
2.0
1.5
0.5
–0.5
1.0
0
–1.0
–1.5
–2.0
–2.5
MEAN
Figure 8. RTD ADC Accuracy vs. Temperature (From 10% to 90% of FSR)
Rev. A | Page 12 of 108
Data Sheet ADP1051
1.23
1.22
CS1 COM P ARATO R RE FERE NCE ( V )
1.21
1.20
1.19
1.18
1.17–60 –40 –20 020 40
TEMPERATURE (°C)
60 80 100 120 140
MAX SPEC
MIN SPEC
MAX
MIN
11443-012
MEAN
Figure 9. CS1 OCP Comparator Reference vs. Temperature (1.2 V Reference)
0.280
CS1 COM P ARATO R RE FERENCE ( V )
0.265
0.250
0.235
0.220–60 –40 –20 020 40
TEMPERATURE (°C)
60 80 100 120 140
MAX SPEC
MIN SPEC
MAX
MIN
11443-113
MEAN
Figure 10. CS1 OCP Comparator Reference vs. Temperature (0.25 V Reference)
Rev. A | Page 13 of 108
ADP1051 Data Sheet
THEORY OF OPERATION
The ADP1051 is designed as a flexible, easy to use, digital power
supply controller. The ADP1051 integrates the typical functions
that are needed to control a power supply, such as
Output voltage sense and feedback
Voltage feedforward control
Digital loop filter compensation
PWM generation
Current, voltage, and temperature sense
Housekeeping and I2C/PMBus interface
Calibration and trimming
The main function of controlling the output voltage is performed
through use of the feedback ADCs, the digital loop compensator,
and the digital PWM engine.
The feedback ADCs feature a patented multipath architecture,
with a high speed, low resolution (fast and coarse) ADC and a
low speed, high resolution (slow and accurate) ADC. The ADC
outputs are combined to form a high speed and high resolution
feedback path. Loop compensation is implemented using the
digital compensator. This proportional, integral, derivative (PID)
compensator is implemented in the digital domain to allow easy
programming of filter characteristics, which is of great value in
customizing and debugging designs. The PWM engine generates
up to six programmable PWM outputs for control of primary
side FET drivers and synchronous rectification FET drivers. This
programmability allows many generic and specific switching
power supply topologies to be realized.
Conventional power supply housekeeping features, such as input
voltage sense, output voltage sense, primary side current sense
and secondary side current sense, are included. An extensive set
of protections is offered, including overvoltage protection (OVP),
overcurrent protection (OCP), overtemperature protection (OTP),
undervoltage protection (UVP), and SR reverse current protection
(RCP).
All of these features are programmable through the I2C/PMBus
digital bus interface. This interface is also used for calibrations.
Other information, such as input current, output current, and
fault flags, is also available through this digital bus interface.
The internal EEPROM can store all programmed values and allows
standalone control without a microcontroller. A free, downloadable
GUI is available that provides all the necessary software to program
the ADP1051. To obtain the latest GUI software and a user guide,
visit http://www.analog.com/digitalpower.
The ADP1051 operates from a single 3.3 V power supply and is
specified from −40°C to +125°C.
RTD
SDA
SCL
SYNI/FLGI
SR2
SR1
OUTD
OUTC
ADD
VCORE
AGND
RES
PWM
ENGINE
ADC
OSC
DIGITAL CORE
VREF
PMBUS
8kB
EEPROM
VS–VS+
OVP
CS1
OUTA
ADC
OUTB
VF CS2–CS2+
CTRL
VDD
UVLO
LDO
0.25V
1.2V
DAC
ADC ADC ADC
11443-013
PG/ALT
Figure 11. Functional Block Diagram
Rev. A | Page 14 of 108
Data Sheet ADP1051
PWM OUTPUTS (OUTA, OUTB, OUTC, OUTD, SR1,
AND SR2)
The PWM outputs are used for control of the primary side drivers
and the synchronous rectifier drivers. They can be used for several
topologies, such as hard-switched full bridge, zero-voltage-switched
full bridge, phase shifted full bridge, half bridge, push pull, two-
switch forward, active clamp forward, interleaved buck, and
others. Delays between rising and falling edges can be individually
programmed. Special care must be taken to avoid shootthrough and
cross conduction. It is recommended that the ADP1051 GUI soft-
ware be used to program these outputs. Figure 12 shows an example
configuration to drive a zero-voltage-switched full bridge topology
with synchronous rectification. The QA, QB, QC, QD, QSR1, and
QSR2 switches are driven separately by the PWM outputs (OUTA,
OUTB, OUTC, OUTD, SR1, and SR2). Figure 13 shows an example
of PWM settings for the power stage shown in Figure 12.
The PWM and SRx outputs are all synchronized with each other.
Therefore, when reprogramming more than one of these outputs,
it is important to first update all of the registers and then latch the
information into the shadow registers at one time. During the
reprogramming operation, the outputs are temporarily disabled. To
ensure that new PWM timings and the switching frequency setting
are programmed simultaneously, a special instruction is sent to
the ADP1051 by setting Register 0xFE61[2:1] (the GO commands).
It is recommended that the PWM outputs not in use be disabled via
Register 0xFE53[5:0].
See the PWM Outputs Timing Registers section for additional
information about the PWM timings.
SYNCHRONOUS RECTIFICATION
SR1 and SR2 are recommended for use as the PWM control signals
when synchronous rectification is in use. These PWM signals can
be configured much like the other PWM outputs.
An optional soft start can be applied to the synchronous rectifier
(SR) PWM outputs. The SR soft start can be programmed using
Register 0xFE08[4:0].
When the SR soft start is disabled (Register 0xFE08[1:0] = 00), the
SR signals are immediately turned on to their modulated PWM
duty cycle values.
When the SR soft start is enabled (Register 0xFE08[1:0] = 11), the
SR1 and SR2 rising edges move left from the tRx + tMODU_LIMIT position
to the tRx + tMODULATION position in steps that are set in Register
0xFE08[3:2]. tRx represents the rising edge timing of SR1 (tR5) and
the rising edge timing of SR2 (tR6) (see Figure 68); tMODU_LIMIT
represents the modulation limit defined in Register 0xFE3C (see
Figure 67); tMODULATION represents the real-time modulation value.
The SR soft start is still applicable even if the SR1 and SR2 are not
programmed to be modulated. When the SR soft start is enabled,
the SR1 and SR2 rising edges move left from the tRx + tMODU_LIMIT
position to the tRx position in steps that are set in Register
0xFE08[3:2].
ISOLATORDRIVER
OUTA
OUTB
OUTC
OUTD
SR1 SR2
VIN
QA
QD
QC
QB
QSR2
QSR1
11443-014
DRIVER
Figure 12. PWM Assignment for Zero-Voltage-Switched Full Bridge Topology with Synchronous Rectification
11443-116
Figure 13. PWM Settings for Zero-Voltage-Switched Full Bridge Topology with Synchronous Rectification Using the ADP1051 GUI
Rev. A | Page 15 of 108
ADP1051 Data Sheet
Rev. A | Page 16 of 108
The advantage of the SR soft start is that it minimizes the output
voltage undershoot that occurs when the SR FETs are turned on
without a soft start. The advantage of turning the SRx signals
completely on immediately is that they can help minimize the
voltage transient caused during a load step.
Using Register 0xFE08[4], the SR soft start can be programmed to
occur only once (the first time that the SRx signals are enabled) or
every time that the SRx signals are enabled (for example, when
the system enters or exits deep light load mode).
When programming the ADP1051 to use the SR soft start, ensure
the correct operation of this function by setting the falling edge of
SR1 (tF5) to a lower value than the rising edge of SR1 (tR5) and setting
the falling edge of SR2 (tF6) to a lower value than the rising edge of
SR2 (tR6). During the SR soft start, the rising edges of SRx move
gradually from the right side (the tRx + tMODU_LIMIT position) to the
left side to increase the duty cycle.
The ADP1051 is well suited for dc-to-dc converters in isolated
topologies. Every time a PWM signal crosses the isolation barrier,
a propagation delay is added because of the isolating components.
Using Register 0xFE3A[5:0], an adjustable delay (0 ns to 315 ns in
steps of 5 ns) can be programmed to move both SR1 and SR2 later
in time to compensate for the added propagation delay. In this way,
all the PWM edges can be aligned (see Figure 68).
PWM MODULATION LIMIT AND 180° PHASE SHIFT
The modulation limit register (Register 0xFE3C) can be programmed
to apply a maximum modulation limit to any PWM signal, thus
limiting the modulation range of any PWM output. If modulation
is enabled, the maximum modulation limit is applied to all PWM
outputs collectively. This limit, tMODU_LIMIT, is the maximum time
variation for the modulated edges from the default timing, following
the configured modulation direction (see Figure 14). There is no
setting for the minimum duty cycle limit. Therefore, the user must
set the rising edges and falling edges based on the case with the least
modulation.
t
RX
t
FX
t
RY
t
FY
t
0
t
S
O
UT
X
O
UT
Y
t
MODU_LIMIT
t
MODU_LIMIT
3
t
S
/2
t
S
/2
11443-015
Figure 14. Setting Modulation Limits
Each least significant bit (LSB) in Register 0xFE3C corresponds to
a different time step size, depending on the switching frequency
(see Table 152). If the ADP1051 is to control a dual-ended topology
(such as full bridge, half bridge, or push pull), enable the dual-ended
topology mode using Register 0xFE13[6]. Then the modulation
limit in each half cycle is one half of the modulation value pro-
grammed by Register 0xFE3C.
The modulated edges cannot go beyond one switching cycle. To
extend the modulation range for some applications, the 180°
phase shift can be enabled, using Register 0xFE3B[5:0]. When the
180° phase shift is disabled, the rising edge timing and the falling
edge timing are referred to the start of the switching cycle (see tRx
and tFx in Figure 14). When the 180° phase shift is enabled, the
rising edge timing and the falling edge timing are referred to half
of the switching cycle (see tRY and tFY in Figure 14, which are
referred to tS/2). Therefore, when the 180° phase shift is disabled,
the edges are always located between t0 and tS. When the 180° phase
shift is enabled, the edges are located between tS/2 and 3tS/2.
The 180° phase shift function can be used to extend the maximum
duty cycle in a multiphase, interleaved converter. Figure 15 shows
a dual-phase, interleaved buck converter. The OUTC and OUTD
PWM outputs can be programmed as a 180° phase shift with the
OUTA and OUTB PWM outputs.
The phase shedding function can be used for light load efficiency
improvement. See the Light Load Mode and Deep Light Load
Mode section for more information.
The ADP1051 GUI is recommended for evaluating this feature.
11443-118
LOAD
DC
INPUT DRIVER
DRIVER
OUTA
OUTB
OUTC
OUTD
Figure 15. Dual-Phase Interleaved Buck Converter Controlled by the ADP1051
ADAPTIVE DEAD TIME COMPENSATION (ADTC)
The ADTC registers (Register 0xFE5A to Register 0xFE60 and
Register 0xFE66) allow the dead time between the PWM edges to
be adapted on the fly. The ADP1051 uses the ADTC function only
when the CS1 current value (which represents the input current)
falls below the ADTC threshold (programmed in Register 0xFE5A).
The ADP1051 GUI allows the user to easily program the dead time
values, and it is recommended that the GUI be used for this purpose.
Before the ADTC is configured, its threshold must be programmed.
Each individual PWM rising and falling edge (tRx and tFx) can then
be programmed (Register 0xFE5B to Register 0xFE60) to have a
specific dead time offset at a CS1 current of 0 A.
This offset can be positive or negative and is relative to the nominal
edge position. When the CS1 current is between 0 A and the
ADTC threshold, the amount of dead time is linearly adjusted in
steps of 5 ns.
Data Sheet ADP1051
Rev. A | Page 17 of 108
The averaging period of the CS1 current and the speed of the dead
time adjustment can also be programmed in Register 0xFE66 to
accommodate faster or slower adjustment.
For example, if the ADTC threshold is set to 0.8 A, tR1 has a
nominal rising edge of 100 ns. If the ADTC offset setting for tR1
is 100 ns at a CS1 current of 0 A, tR1 moves to 200 ns when the CS1
current is 0 A and to 150 ns when the CS1 current is 0.4 A.
Similarly, the ADTC can be applied in the negative direction.
LIGHT LOAD MODE AND DEEP LIGHT LOAD MODE
To facilitate efficiency over the load range, the following three
operation modes can be configured in the ADP1051, according to
the programmed CS2 current thresholds:
Normal mode. In normal mode, the SR PWM outputs are in
complement with the primary PWM outputs.
Light load mode. The SR PWM outputs still work, but they are in
phase with the primary PWMs.
Deep light load mode. All PWM outputs can be disabled.
Figure 16 shows the operation timing of a hard-switched full bridge
converter. When the CS2 current (output current) drops across the
light load mode threshold programmed by Register 0xFE19[3:0],
the SR1 and SR2 PWM signals switch from complementary mode
(normal mode) to in-phase mode (light load mode), as shown in
Figure 16.
To achieve normal operation of light load mode, keep in mind the
following:
In a hard-switched full bridge topology having the same power stage
shown in Figure 12, if QA to QD are driven by OUTA to OUTD
separately, program the SR1 output in complement with OUTB and
OUTC in normal mode, and program the SR2 output in
complement with OUTA and OUTD, as shown in Figure 16. In
this case, the OUTA to OUTD outputs are all modulated.
In a zero-voltage-switched full bridge topology having the same
power stage shown in Figure 12 and the PWM settings shown in
Figure 13, SR1 is in complement with OUTC and SR2 is in
complement with OUTA in normal mode. In light load mode, SR1
is in phase with OUTA, and SR2 is in phase with OUTC.
If the hard-switched full bridge, half bridge, and push pull
topologies are used and the primary switches are controlled by
OUTA and OUTB only, SR1 is in complement with OUTB, and SR2
is in complement with OUTA in normal mode. Then, in the light
load mode, SR1 is in phase with OUTA, and SR2 is in phase with
OUTB.
When the CS2 current drops across the deep light load mode
threshold programmed by Register 0xFE1B[3:0], all PWM channels
can be disabled by Register 0xFE1C[5:0]. This allows the ADP1051
to be used in interleaved topologies, incorporating the automatic
phase shedding function in light load mode.
In both light load mode and deep light load mode, the CS2
averaging speed for the threshold can be set from 41 μs to 328 μs
in four discrete steps, using Register 0xFE1E[5:4]. The hysteresis
can be set by Register 0xFE1E[3:2].
The light load mode digital compensator is also used during light
load mode and deep light load mode.
NORMAL MODE
LIGHT LO AD MOD
E
DEEP LIGHT LOAD
MODE
OUTA, OUTD
OUTB, OUTC
SR1, I_SR1
SR2, I_SR2
Vp_T, Ip_T
OUTA, OUTD
OUTB, OUTC
SR1, I_SR1
SR2, I_SR1
Vp_T, Ip_T
OUTA, OUTD
OUTB, OUTC
SR1, I_SR1
SR2, I_SR2
Vp_T, Ip_T
11443-016
Figure 16. Light Load Mode and Deep Light Load Mode
FREQUENCY SYNCHRONIZATION
The frequency synchronizing function of the ADP1051 includes
the synchronization input (SYNI) as a slave device and the
synchronization output (SYNO, using the OUTC or OUTD pin)
as a master device.
Synchronization as a Slave Device
The ADP1051 can be programmed to take the SYNI/FLGI pin signal
as the reference to synchronize the internal programmed PWM
clock with an external clock.
The frequency capture range requirement is for the period of the
external clock that is applied at the SYNI pin to be 90% to 110% of
the period of the internal programmed PWM clock. The minimum
pulse width of the SYNI signal is 360 ns. From the rising edge of the
SYNI signal to the start of the internal clock cycle, there is a 760 ns
propagation delay. Additional delay time is programmed, using
Register 0xFE11, to realize interleaving control with different
controllers.
To achieve a smooth synchronization transition between asynchro-
nous operation and synchronous operation, there is a phase capture
range bit for synchronization in Register 0xFE12[6] for capturing
ADP1051 Data Sheet
the phase of the external clock signal. The ADP1051 detects the
phase shift between the external clock signal and the internal clock
signal when synchronization is enabled. When the phase shift falls
within the phase capture range, synchronization begins.
The ADP1051 synchronizes to the external clock frequency as
follows:
1. The synchronization function is enabled by Register 0xFE12[3]
and Register 0xFE12[0], and the ADP1051 starts to detect the
period of the external clock signal applied at the SYNI/FLGI pin.
2. If all the periods of the consecutive 64 most recent cycles of the
external clocks fall within 90% to 110% of the internal switching
clock period, the ADP1051 uses the latest current cycle as the
synchronization reference, and the period of the external clock
is identified. This interval is t2 or t4, as shown in Figure 17.
Otherwise, the ADP1051 discards this cycle and looks for the
next cycle (frequency capture mode).
3. After the external clock period is determined, the ADP1051
detects the phase shift between the external clock (plus the delay
time set by Register 0xFE11) and the internal PWM signal. If
the phase shift is within the phase capture range, the internal
and external clocks are synchronized (phase capture mode).
4. At this point, the PWM clock is synchronized with the external
clock. Cycle-by-cycle synchronization starts.
5. If the external clock signal is lost at any time, or if the period
exceeds the minimum limit (89% of the internal programmed
frequency) or the maximum limit (114% of the internal
programmed frequency), the ADP1051 takes the last valid
external clock signal as the synchronization reference source.
At the same time, the phase shift between the synchronization
reference and the internal clock is detected. When the phase
shift falls within the phase capture range, the PWM clock
returns to the internal clock set by the internal oscillator.
This interval is t1 or t3, as shown in Figure 17.
This is the first synchronization unlock condition, called
Synchronization Unlocked Mode 1, in which the switching
frequency is out of range (range is 89% to approximately 114%
of the internal programmed frequency).
6. If the period of the external SYNI signal changes significantly
(for example, if the period difference between contiguous cycles
exceeds 280 ns), the ADP1051 takes the last valid external
clock signal as the synchronization reference source. At the
same time, the phase shift between the synchronization
reference and the internal clock is detected. When the phase
shift falls within the phase capture range, the PWM clock
returns to the internal clock set by the internal oscillator.
This is the second synchronization unlock condition, called
Synchronization Unlocked Mode 2, in which the phase shift
exceeds 280 ns.
Figure 17 shows the synchronous operation diagram. The internal
frequency, fSW_INT, is the internal free-running frequency of the
ADP1051. Before the synchronization is locked, the ADP1051
runs at fSW_INT. The external frequency, fSW_EXT, is the frequency of
the external clock that the ADP1051 needs to synchronize. After
synchronization is locked, the ADP1051 runs at fSW_EXT.
The ADP1051 does not allow the switching frequency to run across
the boundaries of 97.5 kHz, 195.5 kHz, or 390.5 kHz on the fly.
Ensure that the external clock does not run across these boundaries.
Otherwise, the internal switching frequency cannot be set within
±10% of these boundaries.
11443-018
UNIT
OFF UNIT
ON
UNIT
ON TIME
EXT E RNAL CL OCK F RE QUENCY
OPE RATI NG SWITCHI NG FRE QUENCY
INT E RNAL CL OCK F RE QUENCY
t
1
t
2
t
4
t
3
f
SW
110% f
SW_INT
114% f
SW_INT
f
SW_INT
90% f
SW_INT
89% f
SW_INT
Figure 17. Synchronization Operation
Rev. A | Page 18 of 108
Data Sheet ADP1051
SYNI/FLGI
SYNI DELAY
TIME SETTING
REG 0xFE11
±3.125%
±6.25%
SYNC OPERATION
AS SLAVE DEVICE
0µs
DEBOUNCE
100µs
DEBOUNCE
FLAGIN FLAG
RESPONSE
REG 0xFE03[ 3: 0]
SYNI MODE
FLGI MODE
SYNI E NABLE
REG 0xFE12[ 3]
OUTC
OUTD
OUT C IN SY NO MO DE
OUT D IN SY NO MO DE
DEBOUNCE TI M E
REG 0xFE12[ 1]
SYNO E NABLE
REG 0xFE12[ 5: 4]
POLARITY
REG 0xFE12[ 2]
PHASE CAP TURE
RANGE SELECTION
REG 0xFE12[ 6]
SYNI/FLGI
SELECTION
REG 0xFE12[ 0]
320ns
DEBOUNCE
11443-017
Figure 18. Synchronization Configuration
11443-019
Figure 19. Edge Adjustment Reference During Synchronization
To ensure a constant dead time before and after synchronization,
Register 0xFE6D to Register 0xFE6F can be set for edge adjustment
referred to tS/2 or tS. For example, the falling edge of OUTA (tF1) is
referred to the ½ × tS position, which means that the time difference
between tF1 and ½ × tS is a constant during synchronization
transition. Figure 19 shows an example of the edge adjustment
reference settings in a full bridge topology.
Synchronization as a Master Device
Register 0xFE12[5:4] can be used to program the synchronization
output (SYNO) function, in which the OUTC pin (Pin 11) or the
OUTD pin (Pin 12) generates a synchronization reference clock
output. When Bit 4 is set, OUTC generates a 640 ns pulse width
clock signal that represents the internal switching frequency. When
Bit 5 is set, OUTD generates a 640 ns pulse width clock signal that
also represents the internal switching frequency.
To compensate the propagation delays in the synchronization scheme
of the ADP1051, the synchronization output signal has a 760 ns lead
time before the start of the internal switching cycle.
The synchronization output signal is always available when VDD
is applied. The VDD_OV fault is the only fault condition that
suspends the synchronization output signal.
OUTPUT VOLTAGE SENSE AND ADJUSTMENT
The output voltage sense and adjustment function is used for
control, monitoring, and undervoltage protection of the remote
output voltage. VS− (Pin 1) and VS+ (Pin 2) are fully differential
inputs. The voltage sense point can be calibrated digitally to remove
any errors due to external components. This calibration can be
performed in the production environment, and the settings can
be stored in the EEPROM of the ADP1051 (see the Power Supply
Calibration and Trim section for more information).
For voltage monitoring, the READ_VOUT output voltage command
(Register 0x8B) is updated every 10 ms. The ADP1051 stores every
ADC sample for 10 ms and then calculates the average value at the
end of the 10 ms period. Therefore, if Register 0x8B is read at least
every 10 ms, a true average value is obtained. The voltage information
is available through the I2C/PMBus interface.
The control loop of the ADP1051 features a patented multipath
architecture. The output voltage is converted simultaneously by two
ADCs: a high accuracy ADC and a high speed ADC. The complete
signal is reconstructed and processed in the digital compensator
to provide a high performance and cost competitive solution.
Rev. A | Page 19 of 108
ADP1051 Data Sheet
Rev. A | Page 20 of 108
Voltage Feedback Sensing (VS+, VS− Pins)
The VS sense point on the power rail requires an external resistor
divider (R1 and R2 in Figure 20) to bring the nominal differential
mode signal to 1 V between the VS+ and VS− pins (see Figure 20).
This external resistor divider is necessary because the VS ADC
input range of the ADP1051 is 0 V to 1.6 V. When R1 and R2 are
known, the VOUT_SCALE_LOOP parameter can be calculated
using the following equation:
VOUT_SCALE_LOOP = R2/(R1 + R2)
In a 12 V system with resistor dividers of 11 kΩ and 1 kΩ, the
VOUT_SCALE_LOOP can be calculated as follows:
VOUT_SCALE_LOOP = 1 kΩ/(11 kΩ + 1 kΩ) = 0.08333
ADP1051
LOAD
DIGITAL
COMPENSATOR
VS+
VS–
R1
R2
VOLTAGE SENSE
REGISTERS
HIGH SPEED
ADC
VOUT_UV_ FAULT FLAG VOUT_UV_FAULT_LIMIT
ACCURATE
ADC
11443-020
Figure 20. Voltage Sense Configuration
Voltage Sense ADCs
Two kinds of sigma-delta (Σ-Δ) ADCs are used in the ADP1051
feedback loop, as follows:
Low frequency (LF) ADC, running at 1.56 MHz
High frequency (HF) ADC, running at 25 MHz
The Σ-Δ ADCs have a resolution of one bit and operate differently
from traditional flash ADCs. The equivalent resolution that is
obtained depends on how long the output bit stream of the Σ-Δ
ADC is filtered.
The Σ-Δ ADCs also differ from Nyquist rate ADCs in that the
quantization noise is not uniform across the frequency spectrum.
At lower frequencies, the noise decreases. At higher frequencies,
the noise increases (see Figure 21).
MAGNITUDE
FREQUENCY
NYQUIST ADC
NOISE
Σ-∆ADC
NOISE
11443-021
Figure 21. ADC Noise Performance
The low frequency ADC runs at approximately 1.56 MHz. For
a specified bandwidth, the equivalent resolution is calculated as
ln(1.56 MHz/BW)/ln(2) = N bits
For example, at a bandwidth of 95 Hz, the equivalent resolution/
noise is
ln(1.56 MHz/95 Hz)/ln(2) = 14 bits
At a bandwidth of 1.5 kHz, the equivalent resolution/noise is
ln(1.56 MHz/1.5 kHz)/ln(2) = 10 bits
The high frequency ADC has a 25 MHz clock. It is comb filtered and
outputs at the switching frequency into the digital compensator. See
Table 5 for equivalent resolution at selected sampling frequencies.
Table 5. Equivalent Resolutions for High Frequency ADC
at Selected Switching Frequencies
fSW (kHz) High Frequency ADC Resolution (Bits)
49 to 87 9
97.5 to 184 8
195.5 to 379 7
390.5 to 625 6
The high frequency ADC has a range of ±25 mV. Using a base
switching frequency of 97.5 kHz at an 8-bit HF ADC resolution,
the quantization noise is 0.195 mV (1 LSB = 2 × 25 mV/28 =
0.195 mV). When the switching frequency increases to 195.5 kHz
at a 7-bit HF ADC resolution, the quantization noise is 0.391 mV
(1 LSB = 2 × 25 mV/27 = 0.391 mV). Increasing the switching
frequency to 390.5 kHz increases the quantization noise to 0.781 mV
(1 LSB = 2 × 25 mV/26 = 0.781 mV).
Output Voltage Adjustment Commands
In the ADP1051, the voltage data for commanding or reading
the output voltage or related parameters is in linear data format.
The linear format exponent is fixed at −10 decimal (see the
VOUT_MODE command, Register 0x20, in Table 21).
The following three basic commands are used for setting the
output voltage:
VOUT_COMMAND command (Register 0x21, Table 22)
VOUT_MARGIN_HIGH command (Register 0x25, Table 26)
VOUT_MARGIN_LOW command (Register 0x26, Table 27)
One of these three values is selected by the OPERATION command
(Register 0x01, Table 13).
The VOUT_MAX command (Register 0x24, Table 25) sets an
upper limit on the output voltage that the ADP1051 can command,
regardless of any other commands or combinations.
During output voltage adjustment, use the VOUT_TRANSITION_
RATE command (Register 0x27, Table 28) to set the rate (in mV/μs)
at which the VS± pins change voltage.
Data Sheet ADP1051
DIGITAL COMPENSATOR
Use the internal programmable digital compensator to change the
control loop of the power supply. A Type III digital compensator
architecture has been implemented. This Type III compensator is
reconstructed by a low frequency filter, with input from the low
frequency ADC, and a high frequency filter, with input from the
high frequency ADC. From the voltage sense ADC outputs to the
digital compensator output, the transfer function of the digital
compensator in z-domain is as follows:
( )
az
bz
c
z
z
m
d
zH −
−
×+
−
×
×
=8.1218.204
where:
a = HF filter pole register values/256 (Register 0xFE32/256 for
normal mode or Register 0xFE36/256 for light load mode).
b = HF filter zero registers values/256 (Register 0xFE31/256 for
normal mode or Register 0xFE35/256 for light load mode)..
c = HF filter gain register values (Register 0xFE33 for normal
mode or Register 0xFE37 for light load mode).
d = LF filter gain register values (Register 0xFE30 for normal
mode or Register 0xFE34 for light load mode).
m is the scale factor, as follows:
m = 1 when 49 kHz ≤ fSW < 97.5 kHz
m = 2 when 97.5 kHz ≤ fSW < 195.5 kHz
m = 4 when 195.5 kHz ≤ fSW < 390.5 kHz
m = 8 when 390.5 kHz ≤ fSW
To tailor the loop response to the specific application, the low
frequency gain (represented by d), the zero location of HF filter
(represented by b), the pole location of HF the filter (represented by
a), and the high frequency gain (represented by c) can all be set up
individually (see the Digital Compensator and Modulation
Setting Registers section).
It is recommended that the ADP1051 GUI be used to program the
compensator. The GUI displays the filter response, using a Bode
plot in the s-domain, and calculates all stability criteria for the
power supply.
To transfer the z-domain value to the s-domain, plug the following
bilinear transformation equation into the H(z) equation:
sf
sf
z(s)
SW
SW
−
+
=2
2
The filter introduces an extra phase delay element into the control
loop. The digital compensator circuit sends the information about
the duty cycle to the digital PWM engine at the beginning of each
switching cycle (unlike an analog controller, which makes decisions
on the duty cycle information continuously). There is an additional
delay for ADC sampling and decimation filtering. This extra phase
delay for phase margin (Φ) is expressed as follows:
Φ = 360 × fC/fSW
where fC is the crossover frequency and fSW is the switching
frequency.
At one-tenth of the switching frequency, the phase delay is 36°. The
GUI incorporates this phase delay into its calculations. Note that
the ADP1051 GUI does not account for other delays, such as gate
driver and propagation delay.
Two sets of registers allow for two distinct compensator responses.
The main compensator, called the normal mode compensator, is
controlled by programming Register 0xFE30 to Register 0xFE33.
The light load mode compensator is controlled by programming
Register 0xFE34 to Register 0xFE37. The ADP1051 uses the light
load mode compensator only when it operates in light load mode
or deep light load mode.
In addition, a dedicated filter is used during soft start. The filter
is disabled at the end of the soft start routine, after which the
voltage loop digital compensator is used. The soft start filter gain
is a programmable value of 1, 2, 4, or 8, using Register 0xFE3D[1:0].
CLOSED-LOOP INPUT VOLTAGE FEEDFORWARD
CONTROL AND VF SENSE
The ADP1051 supports closed-loop input voltage feedforward
control to improve input transient performance. The VF value is
sensed by the feedforward ADC and is used to divide the output
of the digital compensator. The result is fed into the digital PWM
engine. The input voltage signal can be sensed at the center tap in
the secondary windings of the isolation transformer and must be
filtered by an RCD circuit network to eliminate the voltage spike at
the switching node. Alternatively, the input voltage signal can be
sensed from a winding of the auxiliary power transformer.
The VF pin voltage (Pin 5) must be set to 1 V when the nominal
input voltage is applied. The feedforward ADC sampling period is
10 μs. Therefore, the decision to modify the PWM outputs, based
on the input voltage, is performed at this rate.
As shown in Figure 22, the feedforward scheme modifies the
modulation value, based on the VF voltage. When the VF input
is 1 V, the line voltage feedforward has no effect. For example, if
the digital compensator output remains unchanged and the VF
voltage changes to 50% of its original value (still greater than 0.5 V),
the modulation of the edges of OUTx (that are configured for
modulation) doubles.
DIGITAL
COMPENSATOR
DPWM
ENGINE
VF
R1
R2
1/x
Σ-Δ
ADC
READ_VIN
REG 0x88
REG 0x35,
REG 0x36
FEED-
FORWARD
ADC
0.5V TO 1.6V
0V TO 1.6V
VIN_LOW
FLAG REG 0x7C[3] REG 0xFE29[5]
VIN_UV_FAULT
FLAG REG 0x7C[4]
FROM THE V
IN
SENSE CIRCUI T
11443-022
Figure 22. Closed-Loop Input Voltage Feedforward Configuration
Rev. A | Page 21 of 108
ADP1051 Data Sheet
If the digital compensator output remains unchanged and the VF
voltage changes to 200% of its original value (still smaller than 1.6 V),
the modulation of the OUTx edges that are configured for
modulation is divided by 2 (see Figure 23). Register 0xFE3D[3:2] is
used to program the optional input voltage feedforward function.
The VF pin also has a low speed, high resolution Σ-Δ ADC. The
ADC has an update rate of 800 Hz with 11-bit resolution. The
ADC output value is stored in Register 0xFEAC and converted
to the READ_VIN command (Register 0x88). This value provides
information for the input voltage monitoring and flag functions.
VF
DIGITAL
FILTER
OUTPUT
OUTx
t
S
t
S
t
MODULATION
t
MODULATION
11443-023
Figure 23. Closed-Loop Input Voltage Feedforward Changes Modulation
Values
OPEN-LOOP INPUT VOLTAGE FEEDFORWARD
OPERATION
The ADP1051 can run in open-loop input voltage feedforward
operation mode. In this mode, the input voltage is sensed as the
feedforward signal for generation of the PWM outputs.
As shown in Figure 24, the digital compensator output is modified
by a programmable modulation reference. The VF value, which
represents the input voltage, is fed into the feedforward ADC to
divide the modulation reference. The result of this division is then
fed into the PWM engine. The duty cycle value is in inverse
proportion to the input voltage.
Using the following equations:
D =
IN
NOMIN
V
V_
× (tREF × fSW)
and
VOUT =
n
DVIN ×
the output voltage can be derived by
VOUT =
( )
n
ftV
SWREFNOMIN
××
_
where:
D is the duty cycle value.
VIN_NOM is the nominal input voltage.
VIN is the input voltage.
tREF is the modulation reference, which is set by Register 0xFE63
and Register 0xFE64.
fSW is the switching frequency.
VOUT is the output voltage.
n is the turn ratio of the main transformer.
In the equation to derive VOUT, the input voltage, VIN, is cancelled out.
Therefore, the output voltage does not change when the input
voltage changes.
Register 0xFE63 and Register 0xFE64 set the modulation reference,
based on the target output voltage and the nominal input voltage at
which the VF pin voltage is 1 V (see Figure 24).
DPWM
ENGINE
VF
1/x
Σ-Δ
ADC
READ_VIN
REG 0x88
REG 0x35,
REG 0x36
FEED-
FORWARD
ADC
0.5V TO 1.6V
0V TO 1.6V
VIN_LOW
FLAG REG 0x7C[3] REG 0xFE29[5]
VIN_UV_FAULT
FLAG REG 0x7C[4]
FROM THE VIN
SENSE CIRCUI T
MODULATION
REFERENCE
REG 0xFE63 AND REG 0xFE64
11443-024
Figure 24. Open-Loop Feedforward Operation
The PWM settings of open-loop input voltage feedforward operation
are similar to those of general closed-loop operation. The falling edge
timings, rising edge timings, and modulation are set in the same
manner as for closed-loop operation, by using Register 0xFE3E to
Register 0xFE52. Register 0xFE09[4:3] sets the soft start speed of the
modulation edges. Register 0xFE3D[6] enables open-loop feed-
forward operation. Register 0xFE3D[7] is used to enable the soft
start procedure of open-loop feedforward operation.
The flag settings of open-loop feedforward operation are also similar
to those of general closed-loop operation.
Because the output voltage is not regulated in the same manner as
closed-loop operation, some settings, such as the VOUT setting, the
digital compensator settings, and the constant current mode
setting, are not functional. Other settings can be programmed in
a manner that is similar to general closed-loop operation.
Rev. A | Page 22 of 108
Data Sheet ADP1051
Rev. A | Page 23 of 108
OPEN-LOOP OPERATION
The ADP1051 can also run in open-loop operation mode. In this
mode, the rising edges and falling edges of the PWM outputs are
fixed during normal operation. Therefore, the output voltage varies
with the input voltage. The topologies include full bridge, half bridge,
and push pull converters.
The PWM settings of open-loop operation are different from
those of general closed-loop operation.
1. Set the rising edge timings and falling edge timings by using
Register 0xFE3E to Register 0xFE4F. Typically, a duty cycle
setting of ~50% is recommended for ease of zero-voltage-
switching operation. A phase shift function of 180° is preferred
to guarantee balanced PWM outputs.
2. Program Register 0xFE3C to a value of 0x00, which sets the
modulation limit to 0 μs.
3. Apply negative modulation to the falling edges of all PWM
outputs, OUTA to OUTD (or just one pair of them), for soft
start. The soft start of SR1 and SR2 is not recommended.
4. Write 111111 binary to Register 0xFE67[5:0] to set all PWM
channels to follow open-loop operation. Set Register 0xFE09[7]
to enable the soft start procedure. The soft start speed is
specified by Register 0xFE09[4:3].
5. Always set Register 0xFE09[2] = 1. The soft start ramp time
is determined by tF2 − tR2.
Because the output voltage is not regulated, some of the settings,
such as the VOUT setting, digital compensator settings, and constant
current control, are not functional. Other settings can be pro-
grammed to be similar to those of general closed-loop operation.
CURRENT SENSE
The ADP1051 has two current sense inputs: CS1 (Pin 6) and
CS2−/CS2+ (Pin 3 and Pin 4, respectively). These inputs sense,
protect, and control the primary side input current and the secondary
side output current. They can be calibrated to reduce errors due to
the external components.
CS1 Operation (CS1 Pin)
Current Sense 1 (CS1) is typically used for the monitoring and
protection of the primary side current, which is commonly sensed
using a current transformer (CT). The input signal at the CS1 pin is
fed into an ADC for current monitoring. The range of the ADC is
0 V to 1.60 V. The input signal is also fed into an analog comparator
for cycle-by-cycle current limiting and IIN overcurrent fast protection,
with a reference of 0.25 V or 1.2 V set by Register 0xFE1B[6].
The typical configuration for the CS1 current sense is shown in
Figure 25.
The CS1 ADC is used to measure the average value of the primary
side current. The ADC samples at a frequency of 1.56 MHz and
reports a CS1 reading (12 bits) in the READ_IIN command
(Register 0x89), with an asynchronously averaged rate of 10 ms,
52 ms, 105 ms, or 210 ms set by Register 0xFE65[1:0].
REFERENCE
REG 0xF E1B[6]
12 BIT S
CYCLE-BY-CYCLE
CURRENT LIMITING
AND I
IN
FA ST OCP
CS1 ADC
V
IN
11443-025
Figure 25. Current Sense 1 (CS1) Operation
Variou s IIN overcurrent fast fault limits and response actions can
be set for CS1. These are described in the Current Sense and
Limit Setting Registers section.
CS2 Operation (CS2−, CS2+ Pins)
Current Sense 2 (CS2) is typically used for the monitoring and
protection of the output current. The full-scale range of the CS2
ADC is 120 mV. The differential inputs are fed into an ADC
through a pair of external resistors that provide the necessary
level shifting. The CS2+ and CS2− device pins are regulated to
approximately 1.12 V by internal current sources.
Depending on the configuration of the current sense resistor,
the ADP1051 must be programmed in low-side mode or high-side
mode, using Register 0xFE19[7]. Typical configurations are shown
in Figure 26 and Figure 27.
When using low-side current sensing, as shown in Figure 26, the
current sources are 225 μA. Therefore, the required resistor value is
1.12 V/225 μA = 4.98 kΩ, and 4.99 kΩ resistors are preferred.
VOUT
CS2– CS2+
ADC 12 BIT S
ADP1051
225µA225µA
11443-026
Figure 26. CS2 Low-Side Resistive Current Sense
ADP1051 Data Sheet
Rev. A | Page 24 of 108
When using high-side current sensing, as shown in Figure 27, the
current sources are 1.915 mA. Therefore, the required resistor value
is (VOUT − 1.12 V)/1.915 mA. If VOUT = 12 V, 5.62 kΩ resistors are
required.
VOUT
CS2+ CS2–
ADC 12 BIT S
ADP1051
1.915mA1.915mA
11443-027
Figure 27. CS2 High-Side Resistive Current Sense
The ADC samples at a frequency of 1.56 MHz, and the reading
is averaged in an asynchronous fashion. This reading is used to
determine actions on faults, such as the IOUT OC fault, with an
average rate of 82 μs (seven bits) or 328 μs (nine bits), which is set
by Register 0xFE1B[4]. The ADP1051 also reports an output current
reading in the READ_IOUT command (Register 0x8C), with
an average rate of 10 ms, 52 ms, 105 ms, or 210 ms, as set by
Register 0xFE65[1:0].
Various limits and response actions can be set for CS2, such as the
IOUT_OC_FAULT_LIMIT command (Register 0x46) and the
IOUT_OC_FAULT_RESPONSE (Register 0x47) command. These
limits and responses are described in the PMBUS Command Set
and Current Sense and Limit Setting Registers section.
SOFT START AND SHUTDOWN
On/Off Control
The OPERATION command (Regsiter 0x01) and the ON_OFF_
CONFIG command (Register 0x02) control the power-on and
power-off behavior of the ADP1051. The OPERATION command
turns the ADP1051 on and off in conjunction with input from the
CTRL pin (Pin 16). The combination of the CTRL pin input and
serial bus commands required to turn the ADP1051 on and off is
configured by the ON_OFF_CONFIG command. When the
ADP1051 is commanded to turn on, the power supply on (PSON)
signal is enabled, and the ADP1051 follows the soft start procedure to
begin the power conversion.
Soft Start
After VDD power-up and initialization, the PSON signal is enabled
when the ADP1051 is commanded to turn on. The controller waits
for a user specified turn-on delay (TON_DELAY, Register 0x60)
before initiating this output voltage soft start ramp. The soft start is
then performed by actively regulating the output voltage and digitally
ramping up the target voltage to the commanded voltage setpoint.
The rise time of the voltage ramp is programmed, using the TON_
RISE command (Register 0x61), to minimize the inrush currents
associated with the start-up voltage ramp. A nonzero pre-biased
voltage results in a longer turn-on delay and shorter rise time.
11443-029
CTRL
PIN
REG 0x02[1]
REG 0x01[7:6]
REG 0x02[0]
ON
OFF
IMMEDIATE
OFF
DEL A Y OFF
OPERATION
(SOFTWARE) ON
REG 0x 01[ 5: 4 ]
REG 0x 02[ 4: 2 ]
ALWAYS ON
ON/OFF
OPERATION
V
OUT
COMMAND
V
OUT
MARGIN LOW
V
OUT
MARG I N HIG H
IMMEDIATE
OFF
DEL A Y OFF
Figure 28. On/Off Control Diagram
Data Sheet ADP1051
PSON SIGNAL
TON_DELAY
REG 0x60 TON_RISE
REG 0x61
HF ADC SET TL ING
DEBOUNCE
REG 0xFE3D[ 5: 4] PGOOD DEBOUNCE
REG 0xFE0E [ 3: 2]
VOUT
SOFT_START_FILTER FLAG
REG 0xFEA2[ 0]
POWER_OFF FLAG
REG 0x78[ 6] AND REG 0x79[ 6]
t0t1t2t3t4
11443-030
PG/ALT PIN
Figure 29. Soft Start Timing Diagram
When the user turns on the power supply, the following soft start
procedure is initiated (see Figure 29):
1. At t = t0, the PSON signal is enabled by a combination
of the OPERATION command, the ON_OFF_CONFIG
command, and/or the CTRL pin. The ADP1051 verifies that
the initial flags indicate no abnormalities.
2. The ADP1051 waits for the programmed TON_DELAY time
to ramp up the power stage voltage at t1. The soft start filter
gain (set by Register 0xFE3D[1:0]) is used for closed-loop
control.
3. The soft start begins to ramp up the internal reference. The
soft start ramp time is programmed using the TON_RISE
command.
4. At t2, the soft start ramp reaches the output voltage setpoint.
The high frequency ADC starts to settle.
5. Additional high frequency ADC settling debounce time can
be programmed using Register 0xFE3D[5:4]. If the debounce
time is used, the high frequency ADC is activated at t3. The
period between t2 and t3 is the high frequency ADC settling
debounce time. At t3, the control loop is switched from the
soft start filter to the normal filter.
If no faults are present, the PGOOD signal waits for the
programmed debounce time (Register 0xFE0E[3:2]) before
the PG/ALT pin is pulled high at t4.
If a fault condition occurs during the soft start ramp (the time
set by the TON_RISE command, t1 to t2), the ADP1051 responds
as programmed, unless the flag is blanked during soft start. The
user can program which flags are active during the soft start. All
flags are active at the end of the soft start ramp (t2). See the Flag
Blanking During Soft Start section for more information.
The SR1 and SR2 outputs and volt-second balance functions
can also be disabled during the soft start ramp. For more
information, see the Synchronous Rectification section and
Volt-Second Balance Control section, respectively.
Digital Filters During Soft Start
A dedicated soft start filter is used during soft start. The soft start
filter is a pure low frequency filter with a programmable gain. The
filter is disabled at the end of the soft start routine (t2), and then
the general digital compensator is used. The soft start filter gain
is programmed using Register 0xFE3D[1:0]. The soft start filter
is used during the ramp time of the voltage reference, until the
VS high frequency ADC is settled. The user can program (using
Register 0xFE3D[4]) whether a high frequency ADC debounce
time is added. The high frequency ADC debounce time is the
interval from when the high frequency ADC is settled to when
the frequency filter takes action. The debounce time can be
programmed at 5 ms or 10 ms using Register 0xFE3D[5]. During
the time when the soft start filter is in use, the SOFT_START_
FILTER flag is set. It is recommended that a high frequency
ADC debounce time not be used if the fast load transient
occurs during soft start.
Software Reset
The software reset command allows the user to perform a software
reset of the ADP1051. When a 1 is written to Register 0xFE06[0],
the power supply is immediately turned off and then restarted with
a soft start following a restart delay. The restart delay time can be
programmed as 0 ms, 500 ms, 1 sec, or 2 sec (Register 0xFE07[1:0]).
If both TON_DELAY and the restart delay are programmed with
0 ms, a write to this bit does nothing.
Shutdown
When the ADP1051 is commanded to turn off, the PSON signal is
cleared. Depending on the setting of the OPERATION command,
the ADP1051 shuts down immediately or waits for a user specified
turn-off delay (TOFF_DELAY) prior to the shutdown action.
If the ADP1051 is turned off because a fault condition occurs, the
shut-down actions are programmed by the specific fault flag
responses. See the Power Monitoring, Flags, and Fault Responses
section for more information. The PGOOD flag setting debounce
time can be programmed in Register 0xFE0E[1:0]). This debounce
time is from when the PGOOD setting condition is met to when
the PGOOD flag is set and the PG/ALT pin is pulled low.
Rev. A | Page 25 of 108
ADP1051 Data Sheet
Power Good Signals
The ADP1051 has an open-drain, power good pin, PG (PG/ALT,
Pin 17). When the pin is logic high, the power is good. In addition,
the ADP1051 has a power good flag, PGOOD, which is a negation
of power good. When this flag is set, it indicates that the power is
not good. The PG/ALT pin and the PGOOD flag can be
programmed to respond to the flags from the following list:
VIN_UV_FAULT
IIN_OC_FAST_FAULT
IOUT_OC_FAULT
VOUT_OV_FAULT
VOUT_UV_FAULT
OT_FAULT
OT_WARNING
SR_RC_FAULT
Register 0xFE0D is used to program the masking of these flags,
which prevents them from setting the PGOOD flag and driving
the PG/ALT pin low. Register 0xFE0E[1:0] is used to set the
debounce time to drive the PG/ALT pin low and set the PGOOD
flag (see Figure 30).
If the ADP1051 is configured to enter constant current mode after
the IOUT_OC_FAULT flag is triggered, the PGOOD flag and
the PG/ALT pin do not respond to the IOUT_OC_FAULT flag.
The POWER_GOOD_ON command (Register 0x5E) sets the
voltage limit that the output voltage must exceed before
the POWER_GOOD flag (Register 0x79[11]) can be cleared.
Simi-larly, the output voltage must fall below the
POWER_GOOD_ OFF limit (Register 0x5F) for
the POWER_GOOD flag to be set.
The PG/ALT pin is always driven low and the PGOOD flag is
always set when one of the POWER_OFF, SOFT_START_FILTER,
CRC_FAULT, or POWER_GOOD flags is set.
The debounce timings for setting and clearing the PGOOD
flag can be programmed to 0 ms, 200 ms, 320 ms, or 600 ms in
Register 0xFE0E[3:0].
VOLT-SECOND BALANCE CONTROL
The ADP1051 has a dedicated circuit to maintain volt-second
balance in the main transformer when operating in full bridge
topology. This circuit eliminates the need for a dc blocking
capacitor. In interleaved topologies, volt-second balance can also
be used for current balancing to ensure that each interleaved
phase contributes equal power.
The circuit monitors the current flowing in both legs of the full
bridge topology and stores this information. It compensates the
selected PWM signals to ensure equal current flow in the two legs
of the full bridge topology. The CS1 pin is used as the input for this
function.
Several switching cycles are required for the circuit to operate
effectively. The maximum amount of modulation applied to each
edge of the selected PWM outputs is programmable to ±80 ns
or ±160 ns, using Register 0xFE54[2]. The balance control gains
are programmable via Register 0xFE54[1:0].
The compensation of the PWM drive signals is performed
on the edges of two selected outputs, using Register 0xFE55,
Register 0xFE56, and Register 0xFE57. The direction of the
modulation is also programmable in these registers.
The volt-second balance control can be disabled during soft start
with Register 0xFE0C[1].
There are also leading edge blanking functions at the sensed CS1
signal for more accurate control results. The blanking time follows
the CS1 cycle-by-cycle current-limit blanking time (see the
Current Sense section).
To avoid the wrong compensation in light load mode, there is
a CS1 threshold in Register 0xFE38 to enable volt-second balance.
Below this threshold, volt-second balance is not enabled.
DEBOUNCE
DEBOUNCE
DEBOUNCE
DEBOUNCE
DEBOUNCE
DEBOUNCE
VIN_UV_FAULT
IIN_OC_FAST_FAULT
DEBOUNCE
DEBOUNCE
REG 0xFE0D REG 0xFE 0F
REG 0xFE0E [ 3: 0]
DEBOUNCE
PGOOD FLAG
REG 0xFEA0[ 6]
PG/ALT PIN
IOUT_OC_FAULT
VOUT_OV_FAULT
VOUT_UV_FAULT
OT_FAULT
OT_WARNING
SR_RC_FAULT
POWER_OFF
SOFT_START_FILTER
CRC_FAULT
POWER_GOOD
11443-031
Figure 30. PGOOD Programming
Rev. A | Page 26 of 108
Data Sheet ADP1051
CONSTANT CURRENT MODE
Constant current mode is part of the PMBus output current
fault response function. When the output current reaches the
IOUT_OC_FAULT_LIMIT value, the ADP1051 can be
configured to operate in constant current mode, using the
output current as the feedback signal for closed-loop operation
(see Figure 31). To ens ure t hat the output current remains constant,
the output voltage is ramped down linearly as the load resistance
decreases.
VOUT
IOUT
IOUT_OC_FAULT_LIMIT
(REG 0x46)
VOUT NOM INAL
IOUT NOM INAL
11443-032
Figure 31. Constant Current Mode (VOUT vs. IOUT)
Two CS2 output current averaging speeds can be selected via
Register 0xFE1B[4]: a 9-bit CS2 current averaging speed and
a 7-bit CS2 current averaging speed. The 9-bit CS2 current
averaging speed has a VS basic voltage change rate of 1.18 mV/ms.
The 7-bit CS2 current averaging speed has a VS basic voltage
change rate of 4.72 mV/ms. In addition, the output voltage change
rate can be set by Register 0xFE3A[7:6] to 1×, 2×, 4×, or 8× the
VS± basic voltage change rate.
PULSE SKIPPING
The pulse skipping function can reduce the switching loss under
very light load current conditions while keeping the output voltage
stable. Register 0xFE67[6] can be set to activate this function.
When light load mode or deep light load mode is enabled, as the
output current drops, the supply enters discontinuous conduction
mode (DCM). In DCM, the modulation value is a function of the
load current. If a very light load current requires a modulation
value (duty cycle) of less than the threshold set by Register 0xFE69,
pulse skipping mode is enabled. In pulse skipping mode, the PWM
output appears intermittently. If the digital compensator signals
an error requiring a modulation value that is less than the threshold
set by Register 0xFE69, no PWM pulses are generated. If the digital
compensator signals an error requiring a modulation value that is
greater than the threshold set by Register 0xFE69, PWM pulses
are generated.
The pulse skipping mode is always blanked during soft start.
PRE-BIAS STARTUP
The pre-bias start-up function provides the capability to start up
with a pre-biased voltage on the output. It protects the power
supply against existing external voltage on the output during
startup and ensures a monotonic startup before the power supply
reaches full regulation (see Figure 32).
V
OUT
PSON
PWM
OUTPUTS
0V
11443-033
Figure 32. Pre-Bias Startup
The pre-bias start-up function is enabled by Register 0xFE25[7].
During pre-bias startup, the ADP1051 soft start ramp starts at
the existing voltage value sensed on the VS± pins, and the soft
start ramp time is reduced proportionally. The initial PWM
modulation value does not begin with zero but, instead, with
a value that builds a balanced relationship between the input
voltage and the output voltage. This balance avoids the sudden
charging or discharging of the output capacitor and achieves
a monotonic and smooth startup. The initial modulation value
is calculated by the following equation:
IN
NOMIN
NOM
OUT
OUT
NOMMODUINI
MODU
V
V
VV
tt
_
_
__
×
×=
where:
tMODU_INI is the initial modulation value when the controller begins
to generate PWM pulses during startup.
tMODU_NOM is the modulation value set by Register 0xFE39. It
emulates the modulation value when the input voltage and the
output voltage are in the nominal condition.
VOUT is the sensed output voltage.
VOUT_NOM is the nominal output voltage set by VOUT_COMMAND
(Register 0x21).
VIN_NOM is the nominal input voltage when the VF pin voltage = 1 V.
VIN is the sensed input voltage.
In addition, Register 0xFE6C[1] is set for correct operation. To
sense the input voltage (represented by VF) when the power supply
is off, use additional circuitry, such as an auxiliary power circuit,
to sense the input voltage.
If the input voltage signal is not available when the power is off,
the tMODU_INI value is calculated based on the tMODU_NOM and the
output voltage information. In this case, Register 0xFE6C[1]
is cleared to 0.
Rev. A | Page 27 of 108
ADP1051 Data Sheet
The initial modulation value is calculated as
NOMOUT
OUT
NOMMODUINIMODU
VV
tt
_
__
×=
where:
tMODU_INI is the initial modulation value when the controller begins
to generate PWM pulses during startup.
tMODU_NOM is the modulation value set by Register 0xFE39. It
emulates the modulation value when the input voltage and the
output voltage are in the nominal condition.
VOUT is the sensed output voltage.
VOUT_NOM is the nominal output voltage set by VOUT_COMMAND
(Register 0x21).
If the closed-loop line voltage feedforward function is selected,
the input voltage is introduced from the feedforward loop, and
the VIN value is always included for calculation of the initial
modulation value.
SR reverse current protection can be used in pre-bias start-up
mode. See the SR Reverse Current Protection section for details.
SR soft start can also be enabled in this mode to achieve a smooth
transition. See the Synchronous Rectification section for details.
OUTPUT VOLTAGE DROOPING CONTROL
Output voltage drooping control can be used in the ADP1051.
This feature is used for current sharing applications. Output voltage
drooping is introduced digitally by modifying the value of the
digital output voltage reference, based on the output current value.
Two parameters can be configured independently: the drooping
resistor and the output current averaging speed.
The drooping resistor follows the PMBus specifications. The
VOUT_DROOP command (Register 0x28) specifies the drooping
resistor in the range of 0 mΩ to 255 mΩ.
The CS2 (output current) averaging speed dictates how quickly
the output current is sensed for generating the digital voltage
reference. Register 0xFE1E[7:6] can be set to change the output
current update speed from 82 μs to 656 μs. An output current
update of 82 µs is recommended.
VDD AND VCORE
When the voltage of the VDD pin is applied (VDD), there is a
delay before the part can regulate the power supply. When VDD
rises above the power-on reset and UVLO levels, it takes ~20 μs for
the VCORE pin (Pin 18) to reach its operational point of 2.6 V.
The EEPROM contents are then downloaded to the registers. The
download takes approximately an additional 120 μs. After the
EEPROM contents are downloaded, the ADP1051 is ready for
operation; however, it takes a maximum of 52 ms for the ADP1051
to complete initialization of the address after a power-on reset.
Therefore, it is recommended that the master device access the
ADP1051 at least 52 ms after power-on reset.
If the ADP1051 is programmed to power up at this time, the soft
start ramp begins. Otherwise, the part waits for a PSON signal,
as programmed in Register 0x01 and Register 0x02.
To minimize trace length, the proper amount of decoupling
capacitance must be placed between the VDD pin (Pin 19) and the
AGND pin (Pin 20), as close as possible to the device. The same
requirement applies to the VCORE pin (Pin 18). It is recom-
mended that the VCORE pin not be used as a reference or to
generate other logic levels using resistive dividers.
CHIP PASSWORD
On power-up, some registers in the ADP1051 are locked and
protected from being written to or read from. When the chip is
locked, the following commands and all read only registers are
accessible:
OPERATION
ON_OFF_CONFIG
CLEAR_FAULTS
WRITE_PROTECT
RESTORE_DEFAULT_ALL
VOUT_COMMAND
VOUT_TRIM
VOUT_CAL_OFFSET
Unlock the Chip Password
To unlock the chip password, perform two consecutive writes
with the correct password (default value = 0xFFFF) and using
the CHIP_PASSWORD command (Register 0xD7). Between the
two write actions, any read or write action to another register in
this device interrupts the unlocking of the chip password. The
CHIP_PASSWORD_UNLOCKED flag (Register 0xFEA0[7])
is set to indicate that the chip password is unlocked for access.
Lock the Chip Password
To lock the chip password, use the CHIP_PASSWORD command
(Register 0xD7) to write any value other than the correct password.
The CHIP_PASSWORD_UNLOCKED flag (Register 0xFEA0[7])
is then cleared to indicate that the chip password is locked from
access.
Change the Chip Password
To change the chip password, first write the old password, using the
CHIP_PASSWORD command (Register 0xD7). Next, write the
new password, using the same command. The chip password is
changed to the new password. If the chip password is to be changed
permanently, the register contents must be saved in the EEPROM
after the chip password is changed. If the correct chip password is
lost, the RESTORE_DEFAULT_ALL command (Register 0x12)
restores the factory default settings. In this case, all the user settings
are reset.
Rev. A | Page 28 of 108
Data Sheet ADP1051
POWER MONITORING, FLAGS, AND FAULT RESPONSES
The ADP1051 has extensive system and fault condition
monitoring capabilities for the sensed signals. The system
monitoring functions include current, voltage, power, and
temperature readings. The fault conditions include out-of-limit
values for current, voltage, power, and temperature. The limits
for the fault conditions are programmable, and flags are set
when the limits are exceeded.
FLAGS
The ADP1051 has an extensive set of flags, including the PMBus
standard flags and manufacturer specific flags, that are set when
certain limits, thresholds are exceeded or certain conditions are
met. A setting of 1 indicates that a fault or warning event has
occurred. A setting of 0 indicates that a fault or warning event
has not occurred.
PMBus Standard Flags
Figure 33 shows a summary of the ADP1051 PMBus standard fault
status registers. The CLEAR_FAULTS command (Register 0x03)
is used to clear all bits in the PMBus status registers (Register 0x78
to Register 0x7E) simultaneously.
Manufacturer Specific Flags
Register 0xFEA0 to Register 0xFEA2 store the manufacturer
specific flags. These flags include the following:
Housekeeping flags, such as CHIP_PASSWORD_
UNLOCKED, VDD_OV, EEPROM_UNLOCKED, and
CRC_FAULT.
Flags that can be programmed for protection responses, such as
CS3_OC_FAULT, FLAGIN, and SR_RC_FAULT.
Status flags, such as PGOOD, CONSTANT_CURRENT,
LIGHT_LOAD, SYNC_LOCKED, CHIP_ID, PULSE_SKIPPING,
ADAPTIVE_DEAD_TIME, DEEP_LIGHT_LOAD,
modulation, and SOFT_START_FILTER.
For detailed descriptions of these flags, see the Manufacturer
Specific Fault Flag Registers section.
7VOUT_OV_FAULT 7VIN_OV_FAULT
6VOUT_OV_WARNING 6VIN_OV_WARNING
5VOUT_UV_WARNING 5VIN_UV_WARNING
4VOUT_UV_FAULT 4VIN_UV_FAULT
3VOUT_MAX WARNI NG 15 VOUT 3VIN_LOW
2TON_MAX_FAULT 14 IOUT 2IIN_OC_FAST_FAULT
1TOFF_MAX_WARNING 13 INPUT 1IIN_OC_WARNING
0VOUT T RACKING E RROR 12 MFR_SPECIFIC 0PIN_OP_WARNING
11 POWER_GOOD
10 FANS
9OTHER
8UNKNOWN
7IOUT_OC_FAULT 7MANUFACT URE R DE FINE D
6IOUT_OC_LV_FAULT 6MANUFACTURE R DE FI NE D
5IOUT_OC_WARNING 5MANUFACT URE R DE FINE D
4IOUT_UC_FAULT 4MANUFACTURER DE FINE D
3CURRENT S HARE FAUL T 3MANUF ACTURER DEFI NE D
2IN POWER LIMITING MODE 7BUSY 2MANUF ACTURER DE FI NE D
1POUT_OP_FAULT 6POWER_OFF 1MANUF ACTURER DEFI NE D
0POUT_OP_WARNING 5VOUT_OV_FAULT 0MANUFACTURER DE FI NED
4IOUT_OC_FAULT
3VIN_UV_FAULT
2TEMPERATURE
1CML
7OT_FAULT 0NONE O F T HE ABO V E 7FAN 1 F AULT
6OT_WARNING 6F AN 2 FAULT
5UT_WARNING 5FAN 1 W ARNING
4UT_FAULT 4FAN 2 W ARNING
3 RESERVED 3FAN 1 SP E E D OVE RRIDE
2 RESERVED 2FAN 2 SP E E D OVE RRIDE
1 RESERVED 1AIR FLOW FAULT
0 RESERVED 0AIR F LO W W ARNING
7INVALI D/UNSUP P O RTED COMM AND 7 RESERVED 7FAN 3 F AULT
6INVALI D/UNSUP P O RTED DATA 6 RESERVED 6FAN 4 FAULT
5PACKET E RROR CHECK FAI LED 5INPUT A F US E /BREAKE R FAULT 5FAN 3 W ARNING
4MEMORY FAULT DETECTED 4INPUT B F US E /BREAKE R FAULT 4FAN 4 W ARNING
3PROCE S S OR F AULT DE TECT E D 3INPUT A O R’I NG DEVICE FAULT 3FAN 3 SP E ED OVE RRIDE
2 RESERVED 2INPUT B OR’I NG DEVICE FAULT 2FAN 4 SP E E D OVERRIDE
1OT HE R COMM UNICAT ION FAUL T 1OUTPUT OR’ING DEVICE FAULT 1 RESERVED
0OTHER MEMORY OR LOGIC FAULT 0 RESERVED 0 RESERVED
STATUS_OTHER
STATUS_IOUT (RE G 0x7 B)
STATUS_VOUT (REG 0 x7 A)
STATUS_TEMPERATURE (REG 0x7D)
STATUS_WO RD (REG 0x79)
(UPPE R BY TE OF S TATUS _WO RD)
STATUS_FANS_3_4
STATUS_INPUT (REG 0 x7 C)
STATUS_MFR_SPECIFIC
STATUS_FANS_1_2
STATUS_CML (REG 0x7E)
STATUS_BYTE (REG 0x78)
(LOWER BYTE OF STATUS_WORD)
11443-034
Figure 33. Summary of the Fault Status Registers (Only the commands in black are supported by the ADP1051; the commands in gray are not supported.)
Rev. A | Page 29 of 108
ADP1051 Data Sheet
Manufacturer Specific Latched Flags
The ADP1051 has a set of latched flag registers (Register 0xFEA3 to
Register 0xFEA5). The latched flag registers have the same flags as
Register 0xFEA0 to Register 0xFEA2, but the flags in the latched
registers remain set so that intermittent faults can be detected.
Reading a latched flag register resets all the flags in that register.
A PSON signal can also reset the latched flags.
Flags Debounce Time
The debounce timing of the manufacturer specific flags and
the PMBus standard flags is programmable (see Table 6). The
debounce time is the time during which the fault condition
must be continuously triggered before the flag is set. Refer to
the corresponding register settings for more information.
The debounce time is used for flag setting. Only the PGOOD
flag has a debounce time for flag clearing. For all other flags,
the flag reenable delay, specified in Register 0xFE05[7:6] (see
Table 106), functions as the debounce time for flag clearing.
Refer to the Manufacturer Specific Protection Responses
section for details.
Housekeeping Flags
The CHIP_PASSWORD_UNLOCKED flag (Register 0xFEA0[7])
indicates that the chip password is in the unlocked state, and all
the registers can be accessed.
The VDD_OV flag (Register 0xFEA0[0]) is set when the VDD
voltage exceeds the VDD OVLO threshold. The debounce time is
programmable as 2 μs or 500 μs, using Register 0xFE05[4]. When
the flag is set, the ADP1051 shuts down. The flag is always cleared
when Register 0xFE05[5] is set, regardless of the VDD voltage.
The EEPROM_UNLOCKED flag (Register 0xFEA2[3]) indicates
that the EEPROM is in the unlocked state and can be updated.
The CRC_FAULT flag (Register 0xFEA2[2]) indicates that an error
has occurred when downloading the EEPROM contents to the
internal registers. The device shuts down and requires a PSON
signal (programmed in Register 0x01 and Register 0x02) and/or
the toggling of the CTRL pin (Pin 16) to restart.
Flag Blanking During Soft Start
Flag blanking means that when a fault condition is met, the
corresponding flag is set, but there are no related actions.
The following flags are always blanked during soft start:
VOUT_UV_FAULT
OT_FAULT
The following flags can be programmed to be blanked during soft
start, using Register 0xFE0B:
VOUT_OV_FAULT (Bit 0)
CS3_OC_FAULT (Bit 1)
IOUT_OC_FAULT (Bit 2)
IIN_OC_FAST_FAULT (Bit 3)
VIN_UV_FAULT (Bit 4)
LIGHT_LOAD (Bit 5)
DEEP_LIGHT_LOAD (Bit 5)
FLAGIN (Bit 6)
SR_RC_FAULT (Bit 7)
If a flag is blanked during soft start, it is also blanked during the
TON_DELAY time.
Table 6. Flag Debounce Time
Flag
Debounce Time
Register
VOUT_OV_FAULT 0 μs, 1 μs, 2 μs, 8 μs 0xFE26[7:6]
VOUT_UV_FAULT
0 ms, 20 ms, 40 ms, 80 ms, 160 ms, 320 ms, 640 ms, 1280 ms
0x45[2:0]
IOUT_OC_FAULT 0 ms, 20 ms, 40 ms, 80 ms, 160 ms, 320 ms, 640 ms, 1280 ms 0x47[2:0]
OT_FAULT 1 sec 0x50[2:0]
OT_WARNING 0 ms, 100 ms 0xFE2F[2]
CS3_OC_FAULT 0 ms, 10 ms, 20 ms, 200 ms 0xFE19[6:5]
VIN_UV_FAULT 0 ms, 2.5 ms, 10 ms, 100 ms 0xFE29[1:0]
FLAGIN 0 μs, 100 μs 0xFE12[1]
SR_RC_FAULT 40 ns, 200 ns 0xFE1A[3]
VDD_OV 2 μs, 500 μs 0xFE05[4]
PGOOD 0 ms, 200 ms, 320 ms, 600 ms 0xFE0E[3:0]
Rev. A | Page 30 of 108
Data Sheet ADP1051
First Flag ID Recording
When the ADP1051 registers one or several fault conditions,
it stores the first flag in a dedicated first flag ID register (Regi-
ster 0xFEA6). The first flag ID represents the first flag that
triggers a shutdown response. The following types of flags are
not recorded in the first flag ID register:
Flags that are configured to be ignored
Flags that have a configured response causing the PWM outputs
to be disabled, but that do not use a soft start to reenable the
PWM outputs after the fault is resolved
Flags that have a configured response causing the synchronous
rectifiers to be disabled
The first flag ID register gives the user more information for
fault diagnosis than a simple flag. This register also stores the
previous first fault ID.
The status of the first flag ID register can be saved to the EEPROM,
as well, by setting Register 0xFE0C[3]. To limit the number of
writes to the EEPROM, only the first flag after a VDD power reset
can be saved to the EEPROM. During the next VDD power-on,
the first flag ID is downloaded from the EEPROM and loaded
to the first flag ID register (Register 0xFEA6).
Figure 34 shows the timing diagram for the first flag ID recording
scheme. Table 7 describes the actions shown in Figure 34.
VDD
FLAG Y
FLAG Z
POWER SUPPLY
STATUS
FIRST FLAG ID
(CURRENT)
FIRST FLAG ID
(PREVIOUS)
EEPROM
UPDATE
t0t1t3t5
t2t4t7t9
t6t8
YX Z
X0 Y
11443-035
Figure 34. First Flag Timing
Table 7. First Flag ID Timing1
Step Action
Power
Supply
First Flag ID in Register First Flag ID in EEPROM
Previous ID Current ID Previous ID Current ID
t0 As an example, the previous ID and the current ID in the EEPROM
are 0 and Flag X, respectively. When the VDD voltage is applied on
the ADP1051, the first flag ID is downloaded from the EEPROM
to the first flag ID register (Register 0xFEA6).
On 0 Flag X 0 Flag X
t1 A fault (Flag Y) shuts down the power supply. In the first flag ID
register, Flag Y is now the current flag ID, and Flag X is the previous
flag ID. The first flag ID register is updated accordingly. The EEPROM
is then updated to save this information.
Off Flag X Flag Y Flag X Flag Y
t2 Another fault (Flag Z) occurs while the power supply is off.
Because Flag Z is not the first flag that caused the shutdown,
neither the first flag ID register nor the EEPROM is updated.
Off Flag X Flag Y Flag X Flag Y
t3 Flag Y is cleared, but Flag Z keeps the power supply off. The first
flag ID register and the EEPROM are not updated.
Off Flag X Flag Y Flag X Flag Y
t4 Flag Z is cleared. The first flag ID register is not updated. Off Flag X Flag Y Flag X Flag Y
t5 The power supply is turned on again after the flag reenable
delay. The first flag ID register is not updated.
On Flag X Flag Y Flag X Flag Y
t6 The fault indicated by Flag Z shuts down the power supply. Flag Z
is now the current first flag ID, and Flag Y is the previous flag ID.
The first flag ID register is updated accordingly. The EEPROM is
not updated to save the information.
Off Flag Y Flag Z Flag X Flag Y
t7 Flag Z is cleared. The first flag ID register is not updated. Off Flag Y Flag Z Flag X Flag Y
t8 The power supply is turned on again after the flag reenable
delay. The first flag ID register is not updated.
On Flag Y Flag Z Flag X Flag Y
t9 The VDD voltage is removed and the power supply is turned off. Off N/A N/A N/A N/A
1 N/A means not applicable.
Rev. A | Page 31 of 108
ADP1051 Data Sheet
VOLTAGE READINGS
Input Voltage Reading
The input voltage, which is reported in the READ_VIN command
(Register 0x88), is updated every 10 ms. The VIN_SCALE_
MONITOR command (Register 0xD8) is set for correct input
voltage reading.
The input voltage is sensed through the VF pin (Pin 5). The
VF ADC has an input range of 1.6 V. The raw data is stored in
Register 0xFEAC. The reading is 11 bits, meaning that the LSB size
is 1.6 V/2048 = 781.25 μ V.
Because the input voltage signal can be sensed through the
switching node of the secondary windings, the voltage drop
caused by the conduction current in the primary switches,
transformer windings, and copper trace adds to the error to
the input voltage sense. The following equation is used to
compensate for the error:
YCOMP = YUNCOMP ± (N × X ÷ 211)
where:
YCOMP is the compensated VF value in Register 0xFEAC[15:5].
YUNCOMP is the uncompensated VF value in Register 0xFEAC[15:5].
N is the compensation coefficient set in Register 0xFE59[7:0],
and the polarity is set in Register 0xFE58[0].
X is the CS1 current value in Register 0xFEA7[15:4].
The compensated VF value is used for conversion of the
READ_VIN value.
Output Voltage Reading
The output voltage is reported in the READ_VOUT command
(Register 0x8B) and updated every 10 ms. The VOUT_SCALE_
MONITOR command (Register 0x2A) is programmed for correct
output voltage reading.
The output voltage value register (Register 0xFEAA) is updated
every 10 ms via the VS low frequency ADC.
The VS low frequency ADC has an input range of 1.6 V. The raw
data is stored in Register 0xFEAA. The reading is 12 bits, which
means that the LSB size is 1.6 V/4096 = 390.625 μV.
CURRENT READINGS
By default, the current readings are updated every 10 ms; however,
Register 0xFE65[1:0] can be used to change the update rate to
52 ms, 105 ms, or 210 ms.
Input Current Reading
The input current is reported in the READ_IIN command
(Register 0x89). The IIN_SCALE_MONITOR command
(Register 0xD9) is set for correct input current reading.
The input current reading is derived from the CS1 ADC, which has
an input range of 1.6 V. The raw data is stored in Register 0xFEA7.
The reading is 12 bits, which means that the LSB size is 1.6 V/
4096 = 390.625 μ V.
Output Current Reading
The output current is reported in the READ_IOUT command
(Register 0x8C). The IOUT_CAL_GAIN command (Regis-
ter 0x38) is programmed for correct output current reading.
The output current reading is derived from the CS2 ADC reading.
The CS2 ADC has an input value range of 120 mV. The raw data
is stored in Register 0xFEA8. The reading is 12 bits, which means
that, within a 120 mV range, the LSB size is 120 mV/4096 =
29.297 μV.
CS3 Current Reading
The CS3 reading is an alternative output current reading that is
calculated using the CS1 reading and the duty cycle values. The
CS3 reading can be used as an alternate output current reading
and protection when the current sense resistor, which provides
the output current signal to CS2, is not used. The output current
reading is derived from the following equation:
IOUT = ICS3 × n
where ICS3 is read from Register 0xFEA9, and n is the turn ratio
of the main transformer (n = NPRI/NSEC).
Each LSB size in Register 0xFEA9 is 4× the LSB size of the CS1
reading in Register 0xFEA7. For example, if 1 LSB = 0.1 A in
Register 0xFEA7[15:4], 1 LSB in Register 0xFEA9[15:4] = 0.4 A.
POWER READINGS
Input Power Reading
The input power value (Register 0xFEAE) is the product of the
VF voltage value in Register 0xFEAC[15:5] and the CS1 current
value in Register 0xFEA7[15:4]. Therefore, a combination of both
voltage and current formulas is used to calculate the power reading
in watts (W). Register 0xFEAE is a 16-bit word. It multiplies two
12-bit numbers and then discards the eight LSBs.
Example: if 1 LSB in Register 0xFEAC[15:5] is 0.01 V and 1 LSB
in Register 0xFEA7[15:4] is 0.01 A, 1 LSB in Register 0xFEAE[15:0]
is 0.01 V × 0.01 A × 28 = 0.0256 W.
Output Power Reading
The output power value (Register 0xFEAF) is the product of the VS
voltage value in Register 0xFEAA[15:4] and the CS2 current value
in Register 0xFEA8[15:4]. Therefore, a combination of both
voltage and current formulas is used to calculate the power
reading in watts. Register 0xFEAF is a 16-bit word. It multiplies
two 12-bit numbers and then discards the eight LSBs.
Example: if 1 LSB in Register 0xFEAA[15:4] is 0.01 V and 1 LSB
in Register 0xFEA8[15:4] is 0.01 A, 1 LSB in Register 0xFEAF[15:0]
is 0.01 V × 0.01 A × 28 = 0.0256 W.
Rev. A | Page 32 of 108
Data Sheet ADP1051
DUTY CYCLE READING
The READ_DUTY_CYCLE command (Register 0x94, which gives
the duty cycle of the PWM output value) is updated every 10 ms.
Register 0xFE58[5:2] is set for correct reading of general PWM
type topologies; these bits select the PWM channel (OUTA to
OUTD) for which the duty cycle value is reported. When phase-
shifted full bridge topology is used, Register 0xFE58[1] must be set
to 1. The duty cycle value is calculated based on the overlapping
of the timing of OUTA and OUTD.
SWITCHING FREQUENCY READING
The READ_FREQUENCY command (Register 0x95) is used to
report the switching frequency information in kHz.
TEMPERATURE READING
The RTD pin (Pin 23) is set up for use with an external negative
temperature coefficient (NTC) thermistor. The RTD pin has an
internal programmable current source. An ADC monitors the
voltage on the RTD pin. The RTD ADC has an input range of
1.6 V. The raw data is stored in Register 0xFEAB. It is a 12-bit
reading, which means that the LSB size is 1.6 V/4096 =
390.625 μ V.
Using Register 0xFE2D[7:6], an internal precision current source
can be configured to generate a 10 μA, 20 μA, 30 μA, or 40 μA
current. This current source can be trimmed, by means of an
internal DAC, to compensate for thermistor accuracy. To s et the
current source to the factory default value of 46 μA, write 0xE6
to Register 0xFE2D.
The output of the RTD ADC is linearly proportional to the voltage
on the RTD pin; however, thermistors exhibit a nonlinear function
of resistance vs. temperature. Therefore, it is necessary to perform
postprocessing on the RTD ADC reading to accurately read the
temperature.
By connecting an external resistor in parallel with the NTC ther-
mistor, linearization is achieved. Figure 36 shows the RTD and
OTP operation. Using the factory default value of 46 μA and
the linearization scheme, the temperature, expressed in degrees
Celsius (°C), can be read directly via the READ_TEMPERATURE
command (Register 0x8D). The temperature reading is derived
from the RTD ADC output, and it is updated every 10 ms. The
ADP1051 implements a linearization scheme that is based on a
preselected combination of external components and current
selection (see the Temperature Linearization Scheme section).
Optionally, the user can process the RTD reading and perform
postprocessing in the form of a lookup table or polynomial
equation to match the specific NTC thermistor used.
In this case, the external resistor in parallel is not needed. With an
internal current source of 46 μA, the equation to calculate the
ADC code at a certain NTC value (RX) is given by the following
formula:
ADC CODE = 46 μA × RX/390.7 μV
For example, at 60°C, the NTC thermistor connected to the
RTD pin is 21.82 kΩ. Therefore,
RTD ADC CODE = 46 μA × 21.82 kΩ/390.7 μV = 2570
For the overtemperature function, the RTD threshold (in volts)
can be transferred through the OT_FAULT_LIMIT command in
Register 0x4F, using the linearization equations shown in the
Temperature Linearization Scheme section.
Alternatively, the temperature reading and overtemperature
protection function can be implemented by applying an external
analog temperature sensor, such as the STLM20. See Figure 35
for more information. Using this solution, the temperature sense
range can be as low as −40°C. To facilitate this approach, the
internal current source should be disabled by writing 0x00 to
Register 0xFE2D and setting Register 0xFE2B[2]. The
temperature reading in °C can be derived by the following
formula:
T = 159.65 −
R2R2R1CODEADC +
×
92.29
where the ADC CODE is the reading in Register 0xFEAB[15:4].
The recommended values of R1 and R2 are 20 kΩ and 10 kΩ,
respectively.
RTD RTD
ADC
RTD TEMPERATURE
VALUE REGIST ER
R2
10kΩ
10µA/20µA/30µA/40µA
REG 0xFEAB[ 15: 4]
R1
20kΩ
STLM20
VOUT
GND
11443-037
Figure 35. Temperature Sensing by an Analog Temperature Sensor
RTD RTD
ADC
100kΩ
NTC
OT_FAULT_LIMIT
REG 0x4F
RTD TEMPERATURE
VALUE REGIST ER
OT_FAULT
RESPONSE
16.5kΩ
10µA/20µA/30µA/40µA
REG 0xFEAB[ 15: 4]
SIGNAL
CONDITIONING TEMPERATURE
VALUE IN
CELSIUS
READ_TEMPERATURE
REG 0x8D OT_FAULT FLAG
REG 0x7D[ 7] PGOOD
OT_FAULT_RESPONSE
REG 0x50
11443-036
Figure 36. RTD and OTP Operation
Rev. A | Page 33 of 108
ADP1051 Data Sheet
TEMPERATURE LINEARIZATION SCHEME
The ADP1051 linearization scheme is based on a combination of
a thermistor (R25 = 100 kΩ, 1%), an external resistor (16.5 kΩ,
1%), and the 46 µA current source, preselected for best
performance when linearizing measured temperatures in the
industrial range.
The NTC thermistor that is required must have a resistance of
R25 = 100 kΩ, 1%, such as the NCP15WF104F03RC (beta = 4250,
1%). It is recommended that 1% tolerance be used for both the
resistor and beta values. The linearization equations show the
relationship between the RTD voltage, VRTD (in volts), and
temperature reading, T (in degrees Celsius).
If T < 104°C,
VRTD = (130 – T) ×
256
6.1
If T ≥ 104°C,
VRTD = (156 – T) ×
512
6.1
where T represents the temperature reading in Register 0x8D.
Figure 37 shows the temperature linearization curves.
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
10 20 30 40 50 60
TEMPERATURE (°C)
70 80 90 100 110 120 130
RTD VO LTAGE (V)
LINEARIZATION VOLT-TEMP CURVE
ACTUAL VOLT-TEMP CURVE
11443-038
Figure 37. Temperature Linearization Scheme Curves
Using the internal linearization scheme, the READ_TEMPERA-
TURE command (Register 0x8D) returns the current temperature
in degrees Celsius. For overtemperature protection, the user can
directly set the OT_FAULT_LIMIT command (Register 0x4F) in
degrees Celsius. See the OT_FAULT and OT_WARNING section
for more information.
PMBUS PROTECTION COMMANDS
VOUT Overvoltage Protection (OVP)
The VOUT overvoltage protection feature in the ADP1051
follows PMBus specifications. The limits are programmed in
the VOUT_OV_FAULT_LIMIT command (Register 0x40) to
correspond to the voltage between 75% and 150% of the nominal
output voltage. The responses are programmed using the VOUT_
OV_FAULT_RESPONSE command (Register 0x41). The
VOUT_OV_FAULT flag (Register 0x78[5], Register 0x79[5],
and Register 0x7A[7]) is set when the voltage reading exceeds the
overvoltage limit.
In a direct parallel system, multiple power supply units are
connected directly in parallel without any OR’ing device. An
overvoltage condition in one power supply can raise the common
bus voltage, causing the activation of overvoltage protection in
the other power supplies connected to the common bus. As a
result of this overvoltage protection action, the common bus
may fail. The ADP1051 provides a highly flexible, conditional
overvoltage protection function for redundant control in a direct
parallel system. It consists of an overvoltage detection block, a
modulation flag triggering block, and an overvoltage response
block (see Figure 38).
VOUT_OV_FAULT
DEBOUNCE
REG 0xFE26
VO
OVP
VS– VOUT_OV_FAULT_RESPONSE
REG 0x41
MODULATION
VALUE
MODULATION
THRESHOLD
REG 0xFE6B
AND
AND
0
00
0
00EXTENDED
VOUT_OV_FAULT_RESPONSE
REG 0xFE01
VOUT_OV_FAULT_LIMIT
REG 0x40
VOUT_OV_FAULT
REG 0x7A[ 7]
OVP SELECTION
REG 0xFE6C[ 0]
LARGE_MODULATION
REG 0xFE6C[ 2]
DAC
11443-039
Figure 38. VOUT Overvoltage Protection Circuit Implementation
Rev. A | Page 34 of 108
Data Sheet ADP1051
In the overvoltage detection block, there is an internal analog
comparator to detect the output voltage and generate the VOUT_
OV_FAULT flag when an overvoltage condition occurs. The over-
voltage reference voltage is set in Register 0x40. The debounce
time of the flag setting can be programmed for 0 μs, 1 μs, 2 μs, or
8 μs, using Register 0xFE26[7:6]. There is also a 40 ns propagation
delay, which is measured from the time when the OVP voltage
exceeds the threshold to the time when the comparator output
status is changed.
In the modulation flag triggering block, the real-time modulation
value is compared to the internal reference to generate the
LARGE_MODULATION flag. Register 0xFE6C[2] sets the
LARGE_MODULATION flag when the real-time modulation
value exceeds the modulation threshold set by Register 0xFE6B.
In the overvoltage responses block, there are two groups of over-
voltage protection responses: the VOUT_OV_FAULT_RESPONSE
PMBus command, set in Register 0x41, and the extended VOUT_
OV_FAULT_RESPONSE, set in Register 0xFE01[7:4].
There is a conditional OVP enable switch in Register 0xFE6C[0].
If the switch is cleared to 0, the conditional OVP function is
disabled and the OVP response always follows the VOUT_OV_
FAULT_RESPONSE PMBus command (Register 0x41). If the
switch is set to 1, the OVP response follows the VOUT_OV_
FAULT_RESPONSE command or the extended VOUT_OV_
FAULT_RESPONSE, depending on the status of the LARGE_
MODULATION flag.
For example, when using a direct parallel system, if the VS+ pin
(Pin 2) and the VS− pin (Pin 1) in one power supply unit (PSU)
are shorted and this PSU experiences overvoltage failure, all the
PSUs detect the overvoltage signal. The LARGE_MODULATION
flag is used to identify the failed PSU. Typically, the failed PSU is
shut down, and the other PSUs continue to operate normally.
The modulation threshold is typically set with a value that is
slightly less than the modulation limit setting in Register 0xFE3C;
however, the modulation limit can change when the ADP1051
unit acts as a slave device to synchronize with an external clock
(see the Switching Frequency and Synchronization Registers
section for more information).
For more information about extended overvoltage protection,
see the Manufacturer Specific Protection Responses section and
the related register settings.
VOUT Undervoltage Protection (UVP)
The VOUT undervoltage protection feature follows PMBus specifi-
cations. The limits are programmed using the VOUT_UV_
FAULT_LIMIT command (Register 0x44), and the responses are
programmed in the VOUT_UV_FAULT_RESPONSE command
(Register 0x45). When the voltage reading in the READ_VOUT
command (Register 0x8B) falls below the VOUT_UV_FAULT_
LIMIT value, the VOUT_UV_FAULT flag in Register 0x7A[4]
is set.
During the period of the soft start ramp, the turn-on delay time
is specified by the TON_DELAY command (Register 0x60), and
the flag reenabled time is specified by Register 0xFE05[7:6]. The
VOUT_UV_FAULT flag is always blanked. Under these con-
ditions, the VOUT_UV_FAULT flag is never triggered by an
undervoltage condition.
IOUT Overcurrent Protection (OCP)
The IOUT overcurrent protection feature in the ADP1051 follows
PMBus specifications. The CS2 current sense information is used
for IOUT overcurrent protection. The limits are programmed in
the IOUT_OC_FAULT_LIMIT command (Register 0x46), and
the responses are programmed in the IOUT_OC_FAULT_
RESPONSE command (Register 0x47). The IOUT_OC_FAULT
flag in Register 0x78[4], Register 0x79[4], and Register 0x7B[7]
is set when the current reading in the READ_IIN command
exceeds the IOUT_OC_FAULT_LIMIT value.
When the IOUT overcurrent fault is triggered, the ADP1051 can
be programmed to enter constant current mode. Refer to the
Constant Current Mode section for more information.
OT_FAULT and OT_WARNING
The overtemperature protection feature in the ADP1051 follows
PMBus specifications. With the default setting, the OTP limit
is programmed using the OT_FAULT_LIMIT command in
Register 0x4F, and the response is programmed using the
OT_FAULT_RESPONSE command (Register 0x50).
There is an overtemperature warning flag, OT_WARNING,
in Register 0x7D[6]. The OT_WARNING limit is less than the
OT_FAULT_LIMIT, with an overtemperature hysteresis specified
by Register 0xFE2F[1:0].
When the temperature sensed at the RTD pin (Pin 23) exceeds the
OT_WARNING limit, the OT_WARNING flag (Register 0x7D[6])
is set. When the temperature sensed at RTD pin exceeds the
OT_FAULT_LIMIT, the OT_FAULT flag (Register 0x7D[7]) is set.
The OT_FAULT and OT_WARNING flags are cleared when the
temperature falls below the OT_WARNING limit (see Figure 39).
The OT_FAULT flag and the OT_WARNING flag can each be
separately set to trigger the PGOOD flag and drive the PG/ALT
pin (Pin 17) low.
TEMPERATURE
TIME
OT_FAULT_LIMIT
OT_WARNING LIMIT
OT HYSTERESIS
OT_FAULT FLAG IS SET
OT_WARNING
FLAG IS SET
OT_FAULT AND OT _ WARNING
FLAGSARE CL E ARE D
OT_FAULT FLAG
OT_WARNI NG FLAG
11443-040
Figure 39. OT Protection and OT Warning Operation
Rev. A | Page 35 of 108
ADP1051 Data Sheet
Optionally, the user can process the RTD reading and use the
linearization equation to determine the overtemperature
protection setting. This allows the user to program the RTD
threshold for greater overtemperature protection accuracy.
Alternatively, if an analog temperature sensor, such as the STLM20,
is used, the OT_FAULT limit can still be programmed using the
OT_FAULT_LIMIT command (Register 0x4F), but a conversion
equation is needed.
Using Figure 35 as an example, assume that R1 and R2 are 20 kΩ
and 10 kΩ, respectively, and the value in Register 0x4F is
TOT_SET_LIMIT.
If TOT_SET_LIMIT < 104 decimal,
TOT_ACTUAL_LIMIT = 1.6039 × TOT_SET_LIMIT − 48.8623
If TOT_SET_LIMIT ≥ 104 decimal
TOT_ACTUAL_LIMIT = 0.801967 × TOT_SET_LIMIT + 34.5423
Table 8 shows some typical OTP threshold settings when using
an analog temperature sensor, such as the STLM20.
Table 8. Typical OT Fault Limit Settings When Using
an Analog Temperature Sensor
TOT_SET_LIMIT
OT Limit Programmed
in Register 0x4F (In Decimal)
TOT_ACTUAL_LIMIT
Actual OT Limit (°C)
55 39.35
60 47.37
65 55.39
70 63.41
75 71.43
80 79.45
85 87.47
90 95.49
95 103.51
100
111.53
105 118.75
110 122.76
115 126.77
120 130.78
125 134.79
130 138.80
If the STLM20 is used, the temperature hysteresis can be set
using Register 0xFE2F[1:0], as follows:
00 = 3.21°C, 01 = 6.42°C, 10 = 9.62°C, or 11 = 12.83°C.
VIN_ON and VIN_OFF
Two PMBus commands, VIN_ON (Register 0x35) and VIN_OFF
(Register 0x36), allow the user to set the input voltage on and off
limits independently.
The VIN_LOW flag in Register 0x7C[3] is set at initialization.
When the input voltage exceeds the VIN_ON limit, the VIN_LOW
flag is cleared. If the PSON signal is asserted, the power conversion
starts. When the input voltage drops below the VIN_OFF limit,
the VIN_LOW flag is set and the power conversion stops. The
delay time for the power conversion start and stop can be set
separately by Register 0xFE29[3:2] and Register 0xFE29[4].
Alternatively, if the input voltage signal is not available before
startup, the VIN_ON and VIN_OFF commands can be set for
input voltage undervoltage protection using Register 0xFE29[5].
The VIN_UV_FAULT flag in Register 0x78[3], Register 0x79[3],
and Register 0x7C[4] is set if the input voltage reading falls below
the VIN_OFF limit.
The debounce time of the VIN_UV_FAULT flag setting can
be programmed at 0 ms, 2.5 ms, 10 ms, or 100 ms, using Regis-
ter 0xFE29[1:0]. Because the VIN reading is averaged every 1 ms,
there is an additional debounce time of up to 1 ms.
The response to the VIN_UV_FAULT flag is programmed via the
VIN_UV_FAULT_RESPONSE bits (Register 0xFE02[7:4]). Refer
to the Manufacturer Specific Protection Responses section and
the related register settings for details.
MANUFACTURER SPECIFIC PROTECTION
COMMANDS
CS1 Cycle-by-Cycle Current Limit
CS1 cycle-by-cycle current limit is implemented using an internal
analog comparator (see Figure 25). When the voltage at the CS1
pin (Pin 6) exceeds the threshold set by Register 0xFE1B[6], the
comparator output is triggered high and an internal flag (CS1_
OCP, which is not accessible by the user and, therefore, not listed
in the register tables) is triggered. There is a 105 ns (maximum)
propagation delay in the comparators.
A blanking time of 0 ns, 40 ns, 80 ns, 120 ns, 200 ns, 400 ns, 600 ns,
or 800 ns can be set to ignore the current spike at the beginning of
the current signal. The blanking time is set in Register 0xFE1F[6:4].
During this time, the comparator output is ignored. The blanking
time of the CS1_OCP flag can be referenced to the rising edges
of OUTA, OUTB, OUTC, and OUTD, using Register 0xFE1D[3:0].
A debounce time of 0 ns, 40 ns, 80 ns, or 120 ns can also be added
to improve the noise immunity of the CS1 OCP comparator output
circuit. The debounce time is set using Register 0xFE1F[1:0].
This is the minimum time that the CS1 signal must be constantly
above the threshold before it takes action.
Rev. A | Page 36 of 108
Data Sheet ADP1051
Rev. A | Page 37 of 108
Figure 40 shows an example of CS1 cycle-by-cycle current-limit
timing, with the rising edge of OUTA as the blanking time
reference. When the CS1_OCP flag is set, it is not cleared until
the beginning of the next switching cycle.
CS1 CYCLE-BY-CYCLE
CURRENT L I M IT T HRE S HO LD
OUTA
CS1 PIN SIGN
A
L
COMPARATOR
OUTPUT
CS1_OCP FLAG
t
0
t
BLANKING
t
BLANKING
t
DEBOUNCING
t
DEBOUNCING
t
S
11443-041
Figure 40. CS1 Cycle-by-Cycle Current-Limit Timing
When the CS1_OCP flag is triggered, Register 0xFE08[6:5] and
Register 0xFE0E[7:4] can be used to disable all PWM outputs for
the remainder of the switching cycle. They are reenabled at the
start of the next switching cycle. During one switching cycle, if
the rising edge of a PWM output occurs after the CS1_OCP flag
is triggered, the PWM remains enabled for the switching cycle.
To avoid current overstress of the body diode of the synchronous
rectifiers, the cycle-by-cycle current-limit actions of the SR1 and
SR2 outputs can be further programmed by Register 0xFE1E[1:0].
They can be programmed in the same way as the other PWM
outputs, or they can be programmed so that when the CS1_OCP
flag is triggered, the SR PWM output is turned on. There is a
145 ns to 180 ns delay (dead time) between the CS1_OCP flag
being triggered and the turning on of the SR PWM outputs.
The falling edges continue to follow the programmed value.
The cycle-by-cycle current limit is always activated regardless
of the IIN overcurrent fast protection settings. The comparator
output can be completely ignored by setting Register 0xFE1F[7].
IIN Overcurrent Fast Protection
There is an internal counter, N. N is a positive integer or zero,
with an initial value of 0. The counters work as follows:
When the CS1_OCP flag is triggered in one cycle (the CS1 OCP
comparator is triggered high), N is counted as NCURRENT =
NPREVIOUS + 2.
If the CS1_OCP flag is not triggered in one cycle and the NPREVIOUS
> 0, NCURRENT = NPREVIOUS − 1.
If the CS1_OCP flag is not triggered in one cycle and the NPREVIOUS
= 0, NCURRENT = 0.
When the value of N reaches the limit specified by IIN_OC_
FAST_FAULT_LIMIT, the IIN_OC_FAST_FAULT flag is
triggered (see Figure 41).
CS1 CYCLE-B
Y
-CYCLE CURRE NT
LIMIT RE FERE NCE
CS1 SIGNAL
COMPARATOR
OUTPUT
IIN_OC_FAST_FAULT
FL AG REG 0xF EA0[5]
IIN_OC_FAST_FAULT
FLAG REG 0x7C[2]
IIN_OC_FAST_FAULT
FLAG REG 0xFEA[5]
t
0
t
S
2
t
S
3
t
S
4
t
S
5
t
S
6
t
S
7
t
S
11443-042
Figure 41. IIN Overcurrent Fast Fault Triggering
For the single-ended topologies, such as forward converter and
buck converter, a switching cycle consists of one cycle. For the
double-ended topologies, such as full bridge converter, half
bridge converter, and push pull converter, there are two cycles
in a switching cycle. The IIN_OC_FAST_FAULT_LIMIT bits
are in Register 0xFE1A[6:4]. In Figure 41, the IIN_OC_FAST_
FAULT_LIMIT value is set to 8.
The response of the IIN_OC_FAST_FAULT flag can be
programmed in the IIN_OC_FAST_FAULT_RESPONSE bits
(Register 0xFE00[3:0]). See the Manufacturer Specific Protection
Responses section and the register settings for the action details.
Matched Cycle-by-Cycle Current Limit in a Half Bridge
Converter
For the half bridge converter, the cycle-by-cycle current-limit
feature, described previously, cannot guarantee the balance of
duty cycles between two half cycles in one switching cycle.
The imbalances of each half cycle can cause the center point
voltage of the capacitive divider to drift from VIN/2 toward either
the ground or the input voltage, VIN. This drift, in turn, can lead
to output voltage regulation failure, transformer saturation, and
doubling of the drain to source voltage (VDS) stress of the
synchronous rectifiers.
To compensate for these imbalances, matched cycle-by-cycle
current limiting is implemented in the ADP1051 by forcing
each cycle to be equalized, or matched, to the previous one.
When the matched cycle-by-cycle current limit is triggered, the
duty cycle in the following half cycle exactly matches the actual
duty cycle in the preceding half cycle. However, the cycle-by-cycle
current limit is always the highest priority to terminate the PWM
channels. For example, if one previous cycle has a duty cycle of
20% under a cycle-by-cycle current-limit condition, the following
cycle should also be matched to a duty cycle of 20%. However,
if the cycle-by-cycle current limit occurs in the following cycle and
it must terminate the PWM with a smaller duty cycle, the cycle-
by-cycle current limit takes higher priority and the duty cycle
can be a value that is smaller than 20%.
The matched cycle-by-cycle current limit is enabled by Regis-
ter 0xFE1D[6]. Register 0xFE1D[5:4] is used to set the PWM
pairs for the matched cycle-by-cycle current limit.
ADP1051 Data Sheet
CS3 Overcurrent Protection
CS3 overcurrent protection provides alternative output overcurrent
protection if the CS2 current sense is not available. The reading
is calculated from the CS1 and duty cycle readings.
The CS3_OC_FAULT flag (Register 0xFEA0[3]) is set when
the CS3 current reading of the eight most significant bits (MSBs)
in Register 0xFEA9 exceeds the CS3_OC_FAULT_LIMIT that is
programmed in Register 0xFE6A. The debounce time of the flag
setting can be programmed at 0 ms, 10 ms, 20 ms, or 200 ms in
Register 0xFE19[6:5]. The response of the CS3_OC_FAULT flag
is programmed in the CS3_OC_FAULT_RESPONSE bits
(Register 0xFE01[3:0]). See the Manufacturer Specific Protection
Responses section and the register settings for specific action
information.
SR Reverse Current Protection
In synchronous rectification applications, the reverse current may
flow from VOUT through the output inductor, synchronous
rectifiers, and current sense resistor to ground. If the synchronous
rectifiers are turned off during a large reverse current condition,
the high voltage stress due to the large di/dt of current flowing
into the output inductor may damage the synchronous rectifiers.
The SR reverse current detection is implemented by an analog
comparator with programmable references. The reverse current
protection limit, SR_RC_FAULT_LIMIT, is programmed using
Register 0xFE1A[2:0]. If the negative differential voltage between
the CS2− pin (Pin 3) and CS2+ pin (Pin 4) falls below the value
programmed in Register 0xFE1A[2:0], the SR_RC_FAULT flag
is triggered. The debounce time for triggering the SR_RC_FAULT
flag is 40 ns or 200 ns, set by Register 0xFE1A[3].
DEBOUNCE
REG 0xFE1A[ 3]
SR_RC_FAULT
FLAG
REG 0xFEA1[ 5]
VOUT
CS2– CS2+
ADC 12 BIT S
ADP1051
225µA
225µA
SR_RC_FAULT_LIMIT
REG 0xFE1A[ 2: 0]
11443-028
Figure 42. SR FET Reverse Current Protection
The SR_RC_FAULT flag response is set in the SR_RC_FAULT_
RESPONSE bits (Register 0xFE03[7:4]) to suppress the reverse
current. Besides the three response options of continuing operation
without interruption, disabling SR1 and SR2, and disabling all
the PWM outputs, there is a fourth fault response mode: changing
the rising edge position of SR1 and SR2.
Under this protection mode, the rising edges of SR1 and SR2 each
maintain a fixed value, effective from the next switching cycle
(typically SR1 and SR2 are set to 50% duty cycle for best
performance). The fixed values of the rising edge timings for SR1
and SR2 can be determined as follows:
tRx + tMODU_LIMIT − tOFFSET
where:
tRx is the timing of the rising edges of SR1 and SR2 (see Figure 68).
tMODU_LIMIT is the modulation limit defined in Register 0xFE3C.
tOFFSET is the offset setting in Register 0xFE68.
After the fault flag is cleared, SR1 and SR2 can be set to return
immediately to normal condition or follow the soft recovery
process, as specified in Register 0xFE03[5:4]. For the best
reverse current protection performance, use the previously
defined settings to fine-tune the SR1 and SR2 PWM timing.
Using this protection mode to set the 50% duty cycle operation
of the SR1 and SR2 signals, energy in the output is discharged
back to the input, and the reverse current is suppressed.
Accordingly, the drain to source voltage (VDS) stress of the
synchronous rectifiers is suppressed. See the Manufacturer
Specific Protection Responses section and the register settings
for specific action information.
FLAGIN Protection
The SYNI/FLGI pin (Pin 13) can be configured in flag input mode
(FLGI). An external signal can be sent to the ADP1051 to trigger
an action. The polarity of the external signal is configured by the
FLGI polarity bit (Register 0xFE12[2]). When the ADP1051
detects an external signal, the FLAGIN flag is set. The response to
the FLAGIN flag is programmed in the FLAGIN_RESPONSE
bits (Register 0xFE03[3:0]). See the Manufacturer Specific
Protection Responses section and the register settings for the
more information about the actions that can be programmed.
VDD OVLO Protection
The ADP1051 has built-in overvoltage protection (OVP) on
its supply rail. The VDD overvoltage response bits (VDD_OV_
RESPONSE), found in Register 0xFE05[5:4], are used to specify
the response to a VDD overvoltage condition.
If Register 0xFE05[5] = 0, the VDD_OV flag is set and the
ADP1051 shuts down when the VDD voltage rises above the
OVLO threshold. When the VDD overvoltage condition ends, the
VDD_OV flag is cleared and the ADP1051 downloads the
EEPROM contents before restarting with a soft start process.
The debounce time of the VDD_OV flag can be programmed
using Register 0xFE05[4].
If Register 0xFE05[5] = 1, the VDD_OV flag is always cleared,
regardless of VDD voltage conditions. The ADP1051 continues to
operate without interruption.
It is recommended that the VDD_OV flag response not be
programmed as always cleared.
Rev. A | Page 38 of 108
Data Sheet ADP1051
MANUFACTURER SPECIFIC PROTECTION
RESPONSES
For the VDD_OV flag and protection action, see the VDD
OVLO Protection section.
The following flags can be configured to trigger protection
responses: IIN_OC_FAST_FAULT, VOUT_OV_FAULT,
CS3_OC_FAULT, VIN_UV_FAULT, FLAGIN, and SR_RC_
FAULT. The VOUT_OV_FAULT flag, which triggers the manu-
facturer specific protection in Register 0xFE01[7:4], is used only
for conditional overvoltage protection. See the VOUT Overvoltage
Protection (OVP) section for details.
Each of the aforementioned flags can be individually programmed
to trigger one of the following responses:
Continue operation without interruption (flag ignored)
Disable SR1 and SR2
Disable all PWM outputs
After the condition that triggered the flag is resolved and the flag is
cleared, the ADP1051 can be programmed to respond as follows:
After the flag reenable delay time elapses, reenable the disabled
PWM outputs with a soft start sequence.
Reenable the disabled PWM outputs immediately without the
soft start process.
Keep the PWM output disabled. A PSON reset signal must be
used to reenable the PWM outputs with a soft start sequence.
For the SR_RC_FAULT flag, there is a fourth response option: The
rising edges of SR1 and SR2 move to tRx + tMODU_LIMIT − tOFFSET. After
the flag is cleared, the ADP1051 can be programmed to respond
as follows:
SR1 and SR2 return to normal with soft start.
SR1 and SR2 return to normal without soft start.
For more information, see the SR Reverse Current Protection
section.
The first flag that causes all PWM outputs to be disabled, and
also requires a soft start if the PWM outputs are reenabled, is
recorded as the first flag ID. For more information about use
of the first flag ID, see the First Flag ID Recording section.
A flag reenable delay can be set for the listed manufacturer
specific flags. This delay is used if the configured action for
a flag is to reenable the PWM outputs after the flag reenable delay.
This delay can be set to 250 ms, 500 ms, 1 sec, or 2 sec, using
Register 0xFE05[7:6].
Rev. A | Page 39 of 108
ADP1051 Data Sheet
POWER SUPPLY CALIBRATION AND TRIM
All the ADP1051 parts are factory trimmed. If the ADP1051 is
not trimmed in the power supply production environment, it is
recommended that components with a 0.1% tolerance be used
for the inputs to the CS1, CS2±, VS±, VF, and OVP pins to meet
data sheet specifications (see the Specifications section).
In the power supply production environment, the ADP1051 can
calibrate items, such as output voltage and trim, for tolerance
errors that are introduced by sense resistors and resistor dividers,
as well as its own internal circuitry. The ADP1051 allows the
user enough trim capability to trim for external components
with a tolerance of ≤0.5%.
To unlock the trim registers for write access, the user must
perform two consecutive write actions with the correct password
(factory default value = 0xFF), using the TRIM_PASSWORD
command (Register 0xD6). Any read or write action to another
register in this device, occurring between these two write actions,
interrupts the unlocking of the chip password.
The trim registers are Register 0xFE14 through Register 0xFE17,
Register 0xFE20, Register 0xFE28, and Register 0xFE2A through
Register 0xFE2C. For complete information about these registers,
see the Manufacturer Specific Extended Commands
Descriptions section.
IIN TRIM (CS1 TRIM)
Using a DC Signal
A known dc voltage (Vx) is applied at the CS1 pin. The IIN_
SCALE_MONITOR command (Register 0xD9) is set to 0x0001.
The READ_IIN input current reading command (Register 0x89)
generates a digital code (representing the input current in amperes)
that is equal to the Vx voltage value. The CS1 gain trim register
(Register 0xFE14) is adjusted until the input current reading in
Register 0x89 reads the correct digital code.
Using an AC Signal
A known current (Ix) is applied to the PSU input. This current
passes through a current transformer, a diode rectifier, and an
external resistor (RCS1) to convert the current information to a
voltage (Vx). This voltage is fed into the CS1 pin. The IIN_SCALE_
MONITOR is calculated as follows:
IIN_SCALE_MONITOR = (NPRI/NSEC) × RCS1
where NPRI and NSEC are the turns of the primary side and secondary
side windings, respectively, of the current transformer.
The READ_IIN input current reading command generates a digital
code, representing the input current, Ix. The CS1 gain trim register
(Register 0xFE14) is adjusted until the input current reading in
Register 0x89 reads the correct digital code.
IOUT TRIM (CS2 TRIM)
CS2 Offset Trim
Offset errors are caused by the combined mismatch of the external
level shifting resistors and the internal current sources. The level
shift resistors must have a tolerance of ≤0.1%. The offset trim has
both an analog and a digital component. With 0 V at the CS2±
inputs, the desired ADC reading is 0 LSB.
The analog offset trim is performed to achieve a differential input
voltage of 0 V. The digital offset trim is performed to achieve an
ADC reading of 0 LSB. It is important to perform the offset trim in
the following order:
1. Select high-side or low-side current sensing, using
Register 0xFE19[7].
2. Set the current sense resistor value, using the IOUT_CAL_
GAIN command (Register 0x38). It is important to note that
the real IOUT_CAL_GAIN value should be slightly greater
than the current sense resistor value, due to possible copper
trace and soldering resistance. The real IOUT_CAL_GAIN
value must be determined for accurate reading of the output
current.
3. Set the digital offset trim value to 0x00, using Register 0xFE16.
4. Adjust the CS2 analog offset trim value (Register 0xFE17)
until the value in Register 0xFEA8 reads as close as possible
to 100 decimal.
5. Increase the CS2 digital offset trim register value, using
Register 0xFE16, until the value in Register 0x8C reads 0 A.
The offset trim is then complete. With 0 V at the CS2± inputs, the
ADC code reads 0, and the READ_IOUT reading is 0 A.
CS2 Gain Trim
After completing the offset trim, perform the gain trim to remove
any mismatch that is introduced by the current sense resistor
tolerance. The ADP1051 can trim for current sense resistors
with a tolerance of ≤1%.
1. Apply a known current (IOUT) across the sense resistor.
2. Adjust the CS2 gain trim value in Register 0xFE15 until the
READ_IOUT value in Register 0x8C reads the value.
The CS2 circuit is now trimmed. After the current sense trim
is complete, the IOUT_OC_FAULT_LIMIT and IOUT_OC_
FAULT_RESPONSE are configured.
VOUT TRIM (VS TRIM)
The voltage sense input at the VS± pins is optimized for sensing
signals at 1 V and cannot sense a signal greater than 1.6 V. It is
recommended that the nominal output voltage be reduced to 1 V
for best performance. The resistor divider introduces errors that
must be trimmed. The ADP1051 has enough trim range to trim
errors that are introduced by resistors with a tolerance of ≤0.5%.
Rev. A | Page 40 of 108
Data Sheet ADP1051
To trim the errors introduced by the resistor divider, use the
following procedure:
1. Set the VOUT_COMMAND (Register 0x21) with the
nominal output voltage value. Set the VOUT_SCALE_
LOOP command (Register 0x29) and the VOUT_SCALE_
MONITOR command (Register 0x2A), based on the resistor
divider information.
2. Enable the power supply with the no-load current. The voltage
of the VS± pins is divided down by the VS resistor divider
to give a target of 1 V at the VS± pins.
3. Adjust the VOUT_CAL_OFFSET trim (Register 0x23) to
ensure that the output voltage is exactly the target output
voltage.
4. Adjust the VS gain trim register (Register 0xFE20) when
the READ_VOUT reading in Register 0x8B is the exact
output voltage reading.
VIN TRIM (VF GAIN TRIM)
The voltage sense inputs are optimized for the VF pin signals at
1 V and cannot sense a signal greater than 1.6 V. A resistor divider
is required to divide the sensed voltage signal into a voltage of
less than 1.6 V. It is recommended that the VF voltage signal be
reduced to 1 V for best performance. The resistor divider
introduces errors, which need to be trimmed.
Use the following procedure:
1. Set the VIN_SCALE_MONITOR command in Register 0xD8
based on the resistor divider information (see Figure 22)
and the turn ratio information of the transformer:
IN_SCALE_MONITOR =
PRI
SEC
N
N
R2R1R2 ×
+
where NPRI and NSEC are the turns of the primary side
and secondary side windings, respectively, of the
transformer.
2. Apply the nominal input voltage at the no load condition
to achieve a targeted voltage of approximately 1 V at the
VF pin.
3. Adjust the VF gain trim register (Register 0xFE28) when
the READ_VIN reading in Register 0x88 is the exact
nominal voltage reading.
4. Adjust the input voltage compensation multiplier
(Register 0xFE59) to make the READ_VIN reading
match the exact input voltage at full load condition.
RTD AND OTP TRIM
The RTD requires two trims, one for the ADC and one for the
current source. To use the internal linearization scheme, addi-
tional trimming procedures are required.
Trimming the Current Source
Register 0xFE2D[7:6] sets the value of the RTD current source to
10 µA, 20 µA, 30 µA, or 40 µA. Register 0xFE2D[5:0] can be
used to fine-tune the current value. By fine-tuning the internal
current source, component tolerance can be compensated and
errors can be minimized. One LSB in Bits[5:0] = 160 nA.
A decimal value of 1 adds 160 nA to the current source set by
Register 0xFE2D[7:6]; a decimal value of 63 adds 63 × 160 nA =
10.08 µA to the current source set by Register 0xFE2D[7:6].
Use Register 0xFE2D[7:6] to program a value for the current
source, selecting the nearest possible option (10 µA, 20 µA, 30 µA,
or 40 µA). Then use Register 0xFE2D[5:0] to achieve the finer
step size.
For example, to use a value of 46 µA as the current source,
follow these steps:
1. Place a known resistor (Rx) from the RTD pin to AGND.
2. Set Register 0xFE2D[7:6] to 11 binary (40 µA).
3. Increase the value of Register 0xFE2D[5:0], 1 LSB at a time,
until the voltage at the RTD pin is VRTD = 46 µA × Rx.
The current source is now calibrated and set to the factory
default value.
Trimming the ADC
The first option for trimming the ADC uses the internal
linearization scheme with 46 µA RTD current, which provides
an accurate reading, expressed in degrees Celsius, read in the
READ_TEMPERATURE command (Register 0x8D) in decimal
format.
Use an R25 = 100 kΩ, 1% accuracy NTC thermistor with beta =
4250, 1% (such as the NCP15WF104F03RC) in parallel with an
external resistor of 16.5 kΩ, 1%, with the ADP1051. With this
NTC thermistor and resistor combination, the ADP1051 default
current source trim is set to 46 µA to achieve the best possible
accuracy over temperatures ranging from 85°C to 125°C.
If an external microcontroller is used, the RTD ADC value
in Register 0xFEAB can be fed into the microcontroller, and
a different linearization scheme can be implemented in terms
of a best-fit polynomial for the selected NTC characteristics.
Rev. A | Page 41 of 108
ADP1051 Data Sheet
APPLICATIONS CONFIGURATIONS
RES RTDADD VCORE AGND
OUTA
OUTB
OUTC
OUTD
CS1 SR1 SR2 VF OVP
SYNI/FLGI
VDD
LOAD
VS+
DC
INPUT
CS2– CS2+ VS–
ADP1051
ADuM3223/
ADuM4223
ADP3624/
ADP3654
11443-004
PG/ALT CTRL SDA SCL
PMBus
Figure 43. Full Bridge Converter
RES RTDADD VCORE AGND
OUTA
OUTB
OUTC
OUTD
CS1 SR1 SR2 VF OVP
SYNI/FLGI
VDD
LOAD
VS+
DC
INPUT
CS2– CS2+ VS–
ADP1051
ADuM3223/
ADuM4223
ADP3624/
ADP3654
11443-005
PG/ALT CTRL SDA SCL
PMBus
Figure 44. Half Bridge Converter
RES RTDADD VCORE AGND
OUTA
OUTB
OUTC
OUTD
CS1 SR1 SR2 VF OVP
SYNI/FLGI
VDD
LOAD
VS+
DC
INPUT
CS2– CS2+ VS–
ADP1051
ADuM3221
ADP3624/
ADP3654
11443-006
PG/ALT CTRL SDA SCL
PMBus
Figure 45. Active Clamp Forward Converter
Rev. A | Page 42 of 108
Data Sheet ADP1051
LAYOUT GUIDELINES
This section explains best practices to ensure optimal performance
of the ADP1051. In general, place all components of the ADP1051
control circuit as close to the ADP1051 as possible. The OVP
and VS+ signals are referred to VS−. All other signals are referred
to the AGND plane.
CS1 PIN
Route the traces from the current sense transformer to the
ADP1051, parallel to each other. Keep the traces near each
other, but far away from the switch nodes.
CS2+ AND CS2− PINS
Route the traces from the sense resistor to the ADP1051 parallel
to each other. A Kelvin connection is recommended for the sense
resistor. Keep the traces near each other, but far away from the
switch nodes.
VS+ AND VS− PINS
Route the traces from the remote voltage sense point to the
ADP1051 parallel to each other. Connect VS− to AGND, with
a low ohmic connection. Keep the traces near each other, but far
away from the switch nodes. Place a 100 nF capacitor from VS−
to AGND to reduce the common-mode noise. If VS− is connected
directly to AGND, the capacitor is not needed.
OUTA TO OUTD, SR1 AND SR2 PWM OUTPUTS
Place 10 Ω resistors between the PWM outputs and isolators or
drivers inputs, especially if the isolators and drivers are far from
the ADP1051. Keep the traces far away from the switch nodes.
VDD PIN
Place decoupling capacitors as close as possible to the ADP1051. A
2.2 μF capacitor connected from VDD to AGND is recommended.
VCORE PIN
Place a 330 nF decoupling capacitor from the VCORE pin to
AGND, as close as possible to the ADP1051.
RES PIN
Place a 10 kΩ, 0.1% resistor from the RES pin to AGND, as close
as possible to the ADP1051.
SDA AND SCL PIN
Route the traces to the SDA and SCL pins parallel to each other.
Keep the traces near each other, but far away from the switch
nodes.
EXPOSED PAD
Solder the exposed pad under the ADP1051 to the PCB AGND
plane.
RTD PIN
Route the traces (including the ground returning trace) from
the thermistor to the ADP1051. Place the thermistor near the
hotspot of the power supply, and keep the thermistor and the
traces away from the switching node. Place the 1 nF filtering
capacitor nearby, in parallel with the thermistor.
AGND PIN
Create an AGND ground plane on the adjacent layer of the
ADP1051 and make a single-point (star) connection to the
power supply system ground.
Rev. A | Page 43 of 108
ADP1051 Data Sheet
PMBus/I2C COMMUNICATION
The PMBus slave allows a device to interface with a PMBus-
compliant master device, as specified by the PMBus Power
System Management Protocol Specification (Revision 1.2,
September 6, 2010). The PMBus slave is a 2-wire interface that
can be used to communicate with other PMBus-compliant devices
and is compatible in a multimaster, multislave bus configuration.
PMBus FEATURES
The function of the PMBus slave is to decode the command
that is sent from the master device and respond as requested.
Communication is established using an I2C-like, 2-wire interface
with a clock line (SCL) and data line (SDA). The PMBus slave is
designed to externally move chunks of 8-bit data (bytes) while
maintaining compliance with the PMBus protocol. The PMBus
protocol is based on the System Management Bus (SMBus)
Specification, Version 2.0, August 2000. The SMBus specification is,
in turn, based on the Philips I2C Bus Specification, Version 2.1,
dated January 2000. The PMBus incorporates the following
features:
Slave operation on multiple device systems
7-bit addressing
100 kb/sec and 400 kb/sec data rates
General call address support
Support for clock low extension (clock stretching)
Separate multibyte receive and transmit FIFOs
Extensive fault monitoring
OVERVIEW
The PMBus slave module is a 2-wire interface that can be used to
communicate with other PMBus-compliant devices. Its transfer
protocol is based on the Philips I2C transfer mechanism. The
ADP1051 is always configured as a slave device in the overall
system. The ADP1051 communicates with the master device
using one data pin (SDA, Pin 15) and one clock pin (SCL, Pin 14).
Because the ADP1051 is a slave device, it cannot generate the
clock signal; however, it is capable of stretching the SCL line to put
the master device in a wait state when it is not ready to respond to
the request of the master.
Communication is initiated when the master device sends
a command to the PMBus slave device. Commands can be read
or write commands, and data is transferred between the devices
in a byte wide format. Commands can also be send commands;
in that case, the command is executed by the slave device upon
receiving the stop bit. The stop bit is the last bit in a complete
data transfer, as defined in the PMBus/I2C communication
protocol. During communication, the master and slave devices
send acknowledge (A) or no acknowledge (A) bits as a method
of handshaking between devices. See the PMBus specification
for a more detailed description of the communication protocol.
When communicating with the master device, it is possible for
illegal or corrupted data to be received by the PMBus slave.
In this case, the PMBus slave must respond to the invalid
command or data, as defined by the PMBus specification, and
indicate to the master device that an error or fault condition has
occurred. This method of handshaking can be used as a first
level of defense against inadvertent programming of the slave
device that can potentially damage the chip or system.
The PMBus specification defines a set of generic PMBus
commands that is recommended for a power management
system; however, each PMBus device manufacturer can choose
to implement and support certain commands that are deemed
fit for the system. In addition, the PMBus device manufacturer
can choose to implement manufacturer specific commands,
the functions of which are not included in the generic PMBus
command set. The list of standard PMBus and manufacturer
specific commands can be found in the PMBUS Command Set
and Manufacturer Specific Extended Command List sections.
PMBUS/I2C ADDRESS
The PMBus address of the ADP1051 is set by connecting an
external resistor from the ADD pin (Pin 22) to AGND. Table 9
lists the recommended resistor values and the associated PMBus
addresses. Eight different addresses can be used.
Table 9. PMBus Address Settings and Resistor Values
PMBus Address Resistor Value (kΩ)
0x70
10 (or connect the ADD pin directly to AGND)
0x71 31.6
0x72 51.1
0x73 71.5
0x74 90.9
0x75 110
0x76
130
0x77 150 (or connect the ADD pin directly to VDD)
The recommended resistor values in Table 9 can vary by ±2 kΩ.
Therefore, it is recommended that 1% tolerance resistors be used
on the ADD pin.
The ADP1051 responds to the standard PMBus broadcast
address (general call) of 0x00. However, when more than one
ADP1051 device is connected to the master device, it is not
recommended that the general call address be used because the
data returned by multiple slave devices is corrupted.
For more information, see the General Call Support section.
DATA TRANSFER
Format Overview
The PMBus slave follows the transfer protocol of the SMBus
specification, which is based on the fundamental transfer protocol
format of the I2C bus specification. Data transfers are byte wide,
lower byte first. Each byte is transmitted serially, most significant
bit (MSB) first. A typical transfer is shown in Figure 46. See the
SMBus and I2C specifications for in-depth discussions of the
transfer protocols.
Rev. A | Page 44 of 108
Data Sheet ADP1051
Rev. A | Page 45 of 108
Figure 46 through Figure 53 use the abbreviations listed in
Table 10.
Table 10. Abbreviations Used in Data Transfer Diagrams
Abbreviation Description Setting1
S Start condition N/A
P Stop condition N/A
Sr Repeated start condition N/A
W Write bit 0
R Read bit 1
A Acknowledge bit 0
A No acknowledge bit 1
1 N/A means not applicable.
Command Overview
Data transfer using the PMBus slave is established using PMBus
commands. The PMBus specification requires that all PMBus
commands start with a slave address, with the R/W bit cleared
to 0, followed by the command code. All PMBus commands that
are supported by the ADP1051 follow one of the protocol types
shown in Figure 47 through Figure 53.
The ADP1051 also supports manufacturer specific extended
commands. These commands follow the same protocol as the
standard PMBus commands; however, the command code
consists of two bytes that range from 0xFF00 to 0xFFAF.
Using the manufacturer specific extended commands, the PMBus
device manufacturer can add an additional 256 manufacturer
specific commands to its PMBus command set.
MASTER TO SLAVE
SLAVE TO MASTER
SPAAW
7-BI T S LAVE
ADDRESS 8- BI T DATA
11443-043
Figure 46. Basic Data Transfer
SPAAW7-BIT SLAVE ADDRES S COMM AND CODE
MASTER TO SLAVE
SLAV E TO M ASTER
11443-044
Figure 47. Send Byte Protocol
ASPAADATA BYTEW
7-BI T SLAVE
ADDRESS COMMAND
CODE
MASTER TO SLAVE
SLAVE TO MASTER
11443-045
Figure 48. Write Byte Protocol
AA COMMAND
CODE AS P
DATA BYTE
LOW
W
7-BI T SLAVE
ADDRESS ADATA BYTE
HIGH
MASTER TO SLAVE
SLAVE TO MASTER
11443-046
Figure 49. Write Word Protocol
A
SAAW
7-BI T SLAVE
ADDRESS COMMAND
CODE PRDATA BYTE
Sr A
7-BI T SLAVE
ADDRESS
MASTER TO SLAVE
SLAVE TO MASTER
11443-047
Figure 50. Read Byte Protocol
AASAAW
7-BI T SL AVE
ADDRESS COMMAND
CODE PRSr 7-BIT SLAVE
ADDRESS
MASTER TO SLAVE
SLAVE TO MASTER
DATA BYTE
LOW DATA BYTE
HIGH A
11443-048
Figure 51. Read Word Protocol
A ASAAW
7-BI T SL AVE
ADDRESS COMMAND
CODE PA
BYTE COUNT =
NDATA BYTE 1 DATA BYTE N
MASTER TO SLAVE
SLAVE TO MASTER
11443-049
Figure 52. Block Write Protocol
SrA7-BIT SLAVE
ADDRESS AR ASAW
7-BI T SLAVE
ADDRESS COMMAND
CODE A
BYTE COUNT =
NDATA BYTE 1
MASTER TO SLAVE
SLAVE TO MASTER
P
A
DATA BYTE N
11443-050
Figure 53. Block Read Protocol
ADP1051 Data Sheet
Clock Generation and Stretching
The ADP1051 is always a PMBus slave device in the overall system;
therefore, the device never needs to generate the clock, which is
done by the master device in the system. However, the PMBus
slave device is capable of clock stretching to put the master in a
wait state. By stretching the SCL signal during the low period, the
slave device communicates to the master device that it is not
ready and the master device must wait.
Conditions in which the PMBus slave device stretches the SCL
line low include the following:
The master device is transmitting at a higher baud rate than the
slave device.
The receive buffer of the slave device is full and must be read
before continuing. This prevents a data overflow condition.
The slave device is not ready to send data that the master has
requested.
Note that the PMBus slave device can stretch the SCL line only
during the low period. Also, whereas the I2C specification allows
indefinite stretching of the SCL line, the PMBus specification
limits the maximum time that the SCL line can be stretched, or
held low, to 25 ms. After this time period, the slave device must
release the communication lines and reset its state machine.
Start and Stop Conditions
Start and stop conditions involve serial data transitions when the
serial clock is at a logic high level. The PMBus slave device moni-
tors the SDA and SCL lines to detect the start and stop conditions
and transition its internal state machine accordingly. Typical
start and stop conditions are shown in Figure 54.
SCL
SDA
START STOP
11443-154
Figure 54. Start and Stop Transitions
GENERAL CALL SUPPORT
The PMBus slave is capable of decoding and acknowledging
a general call address. The PMBus slave device responds to both
its own address and the general call address (0x00). The general
call address enables all devices on the PMBus to be written to
simultaneously.
Note that all PMBus commands must start with a slave address,
with the R/W bit cleared to 0 and followed by the command code.
This is also true when using the general call address to communi-
cate with the PMBus slave device.
10-BIT ADDRESSING
The ADP1051 does not support 10-bit addressing as defined in
the I2C specification.
FAST MODE
Fast mode, with a data rate of 400 kb/sec, uses essentially the
same mechanics as the standard mode of operation; the electrical
specifications and timing are most affected. The PMBus slave is
capable of communicating with a master device operating in fast
mode or in standard mode, which has a data rate of 100 kb/sec.
FAULT CONDITIONS
The PMBus protocol provides a comprehensive set of fault
conditions that must be monitored and reported. These fault
conditions can be grouped into two major categories:
communication faults and monitoring faults.
Communication faults are error conditions associated with the
data transfer mechanism of the PMBus protocol. Monitoring
faults are error conditions associated with the operation of the
ADP1051, such as output overvoltage protection. These fault
conditions are described in detail in the Power Monitoring,
Flags, and Fault Responses section.
TIMEOUT CONDITIONS
The SMBus specification includes three clock stretching
specifications related to timeout conditions.
A timeout condition occurs if any single SCL clock pulse is held
low for longer than the minimum tTIMEOUT value of 25 ms. Upon
detecting the timeout condition, the PMBus slave device has 10 ms
to abort the transfer, release the bus lines, and be ready to accept
a new start condition. The device initiating the timeout is required
to hold the SCL clock line low for at least the maximum tTIMEOUT
value of 35 ms, guaranteeing that the slave device is given enough
time to reset its communication protocol.
DATA TRANSMISSION FAULTS
Data transmission faults occur when two communicating devices
violate the PMBus communication protocol, as specified in the
PMBus specification. See the PMBus specification for more
information about each fault condition.
Corrupted Data, Packet Error Checking (PEC)
Packet error checking is not supported by the ADP1051.
Sending Too Few Bits
Transmission is interrupted by a start or stop condition before
a complete byte (eight bits) has been sent. This function is not
supported; any transmitted data is ignored.
Reading Too Few Bits
Transmission is interrupted by a start or stop condition before
a complete byte (eight bits) has been read. This function is not
supported; any received data is ignored.
Host Sends or Reads Too Few Bytes
If a host ends a packet with a stop condition before the required
bytes are sent/received, it is assumed that the host intended to
stop the transfer. Therefore, the PMBus does not consider this
to be an error and takes no action, except to flush any remaining
bytes in the transmit FIFO.
Rev. A | Page 46 of 108
Data Sheet ADP1051
Host Sends Too Many Bytes
If a host sends more bytes than are expected for the corresponding
command, the PMBus slave considers this a data transmission
fault and responds as follows:
Issues a no acknowledge for all unexpected bytes as they are
received
Flushes and ignores the received command and data
Sets the CML bit in the STATUS_BYTE command register
(Register 0x78[1])
Host Reads Too Many Bytes
If a host reads more bytes than are expected for the corresponding
command, the PMBus slave considers this a data transmission
fault and responds as follows:
Sends all 1s (0xFF) as long as the host continues to request data
Sets the CML bit in the STATUS_BYTE command register
(Register 0x78[1])
Device Busy
The PMBus slave device is too busy to respond to a request
from the master device. This condition is not supported in
the ADP1051.
DATA CONTENT FAULTS
Data content faults may occur when the data transmission is
successful, but the PMBus slave device cannot process the data
that is received from the master device.
Improperly Set Read Bit in the Address Byte
All PMBus commands start with a slave address with the R/W
bit cleared to 0, followed by the command code. If a host starts
a PMBus transaction with R/W set in the address phase
(equivalent to an I2C read), the PMBus slave considers this
a data content fault and responds as follows:
Acknowledges (ACKs) the address byte
Issues a no acknowledge for the command and data bytes
Sends all 1s (0xFF) as long as the host continues to request data
Sets the CML bit in the STATUS_BYTE command register
(Register 0x78[1])
Invalid or Unsupported Command Code
If an invalid or unsupported command code is sent to the
PMBus slave, the code is considered to be a data content fault,
and the PMBus slave responds as follows:
Issues a no acknowledge for the illegal/unsupported command
byte and data bytes
Flushes and ignores the received command and data
Sets the CML bit in the STATUS_BYTE command register
(Register 0x78[1])
Reserved Bits
Accesses to reserved bits are not a fault. Writes to reserved bits
are ignored, and reads from reserved bits return undefined data.
Write to Read Only Commands
If a host performs a write to a read only command, the PMBus
slave considers this a data content fault and responds as follows:
Issues a no acknowledge for all unexpected data bytes as they
are received
Flushes and ignores the received command and data
Sets the CML bit in the STATUS_BYTE command register
(Register 0x78[1])
Note that this is the same error described in the Host Sends Too
Many Bytes section.
Read from Write Only Commands
If a host performs a read from a write only command, the PMBus
slave considers this a data content fault and responds as follows:
Sends all 1s (0xFF) as long as the host continues to request data
Sets the CML bit in the STATUS_BYTE command register
(Register 0x78[1])
Note that this is the same error response that is described in the
Host Reads Too Many Bytes section.
Rev. A | Page 47 of 108
ADP1051 Data Sheet
EEPROM
The ADP1051 has a built-in EEPROM controller that is used
to communicate with the embedded 8000-byte EEPROM.
The EEPROM, also called Flash®/EE, is partitioned into two
major blocks: the information block and the main block. The
information block contains 128 8-bit bytes (for internal use only),
and the main block contains 8000 8-bit bytes. The main block
is further partitioned into 16 pages, with each page containing
512 bytes.
EEPROM FEATURES
The function of the EEPROM controller is to decode the operation
that is requested by the ADP1051 and to provide the necessary
timing to the EEPROM interface. Data is written to or read
from the EEPROM, as requested by the decoded command.
Features of the EEPROM controller include
Separate page erase functions for each page in the EEPROM
Single byte and multibyte (block) read of the information block
with up to 128 bytes at a time
Single byte and multibyte (block) write and read of the main
block with up to 256 bytes at a time
Automatic upload on startup, from the user settings to the
internal registers
Separate commands to upload and download data, from the
factory default or user settings to the internal registers
EEPROM OVERVIEW
The EEPROM controller provides an interface between the
ADP1051 core logic and the built-in EEPROM. The user can
control data access to and from the EEPROM through this
controller interface. Different PMBus commands are available
for the read, write, and erase operations to the EEPROM.
Communication is initiated by the master device sending a
command to the PMBus slave device to access data from or
send data to the EEPROM. Read, write, and erase commands
are supported. Data is transferred between devices in a byte
wide format. Using a read command, data is received from the
EEPROM and transmitted to the master device. Using a write
command, data is received from the master device and stored in
the EEPROM through the EEPROM controller.
PAGE ERASE OPERATION
The main block consists of 16 equivalent pages of 512 bytes
each, numbered Page 0 to Page 15. Page 0 and Page 1 of the
main block are reserved for storing the default settings and user
settings, respectively. The user cannot perform a page erase
operation on Page 0 or Page 1. Page 3 is reserved for storing the
power board parameters for the GUI.
Only Page 4 to Page 15 of the main block can be used to store
data. To erase any page from Page 4 to Page 15, the EEPROM
must first be unlocked for access. For instructions on how to
unlock the EEPROM, see the Unlock the EEPROM section.
Each page of the main block, from Page 4 to Page 15, can be
individually erased using the EEPROM_PAGE_ERASE command
(Register 0xD4). For example, to perform a page erase of Page 10,
execute the following command as shown in Figure 55:
AS PAA DATA BY TEW
7-BI T SLAVE
ADDRESS COMMAND
CODE
MASTER TO SLAVE
SLAVE TO MASTER
11443-051
Figure 55. Example Erase Command
In this example, command code = 0xD4 and data byte = 0x0A.
Note that it is important to wait at least 35 ms for the page erase
operation to complete before executing the next PMBus command.
The EEPROM allows erasing of whole pages only; therefore, to
change the data of any single byte in a page, the entire page must
first be erased (set to logic high) for that byte to be writeable.
Subsequent writes to any bytes in that page are allowed as long
as that byte has not been previously written to a logic low.
READ OPERATION (BYTE READ AND BLOCK READ)
Read from Main Block, Page 0 and Page 1
Page 0 and Page 1 of the main block are reserved for storing the
default settings and the user settings, respectively, and are intended
to prevent third party access to this data. To read from Page 0 or
Page 1, the user must first unlock the EEPROM (see the Unlock
the EEPROM section). After the EEPROM is unlocked, Page 0 and
Page 1 are readable, using the EEPROM_DATA_xx commands
as described in the Read from Main Block, Page 2 to Page 15
section. Note that when the EEPROM is locked, a read from
Page 0 and Page 1 returns invalid data.
Read from Main Block, Page 2 to Page 15
Data in Page 2 to Page 15 of the main block is always readable,
even with the EEPROM locked. The data in the EEPROM main
block can be read one byte at a time or multiple bytes in series,
using the EEPROM_DATA_xx commands (Register 0xB0 to
Register 0xBF).
Before executing this command, the user must program the
number of bytes to read, using the EEPROM_NUM_RD_BYTES
command (Register 0xD2). Also, the user can program the offset
from the page boundary where the first read byte is returned,
using the EEPROM_ADDR_OFFSET command (Register 0xD3).
Rev. A | Page 48 of 108
Data Sheet ADP1051
In the following example, three bytes from Page 4 are read from
the EEPROM, starting from the sixth byte of that page.
1. Set number of return bytes = 3.
A
S PAA 0x030xD2W
7-BI T SLAVE
ADDRESS
MASTER TO SLAVE
SLAVE TO MASTER
11443-055
Figure 56. Set the Return Bytes Number (= 3)
2. Set address offset = 5.
A
S PAA 0x000x050xD3W
7-BI T SLAVE
ADDRESS A
MASTER TO SLAVE
SLAVE TO MASTER
11443-056
Figure 57. Set the Address Offset (= 5)
3. Read three bytes from Page 4.
R
S AAA Sr0xB4W
7-BI T SLAVE
ADDRESS 7- BI T SLAVE
ADDRESS
P
A...
BYT E COUNT =
0x03 DATA BY TE
1A A
DATA BY TE
3
MASTER TO SLAVE
SLAVE TO MASTER
11443-057
Figure 58. Read Three Bytes from Page 4
Note that the block read command can read a maximum of 256
bytes for any single transaction.
WRITE OPERATION
(BYTE WRITE AND BLOCK WRITE)
The user cannot write directly to the information block; this
block is used by the ADP1051 to store the first flag information
(see the First Flag ID Recording section).
Write to Main Block, Page 0 and Page 1
Page 0 and Page 1 of the main block are reserved for storing the
default settings and the user settings, respectively. The user cannot
perform a direct write operation to Page 0 or Page 1 using the
EEPROM_DATA_xx commands. If the user writes to Page 0,
Page 1 returns a no acknowledge. To program the register contents
of Page 1 of the main block, it is recommended that the STORE_
USER_ALL command be used (Register 0x15). See the Save
Register Settings to the User Settings section.
Write to Main Block, Page 2 to Page 15
Before performing a write to Page 2 through Page 15 of the
main block, the user must first unlock the EEPROM (see the
Unlock the EEPROM section).
Data in Page 2 to Page 15 of the EEPROM main block can be
programmed (written to) one byte at a time or multiple bytes in
series, using the EEPROM_DATA_xx commands (Register 0xB0
to Register 0xBF). Before executing this command, the user can
program the offset from the page boundary where the first byte
is written, using the EEPROM_ADDR_OFFSET command
(Register 0xD3).
If the targeted page has not yet been erased, the user can erase
the page, as described in the Page Erase Operation section.
In the following example, four bytes are written to Page 9,
starting from the 257th byte of that page.
1. Set address offset = 256.
AS PAA 0x010x000xD3W
7-BI T SLAVE
ADDRESS A
MASTER TO SLAVE
SLAVE TO MASTER
11443-058
Figure 59. Set the Address Offset (= 256)
2. Write four bytes to Page 9.
AS AA BYT E COUNT = 40xB9
W
7-BI T SLAVE
ADDRESS
MASTER TO SLAVE
SLAVE TO MASTER
PAA ...
DATA BYTE 1 DATA BYTE 4
11443-059
Figure 60. Write Four Bytes to Page 9
Note that the block write command can write a maximum of
256 bytes for any single transaction.
EEPROM PASSWORD
On ADP1051 VDD power-up, the EEPROM is locked and
protected from accidental writes or erases. Only reads from
Page 2 to Page 15 are allowed when the EEPROM is locked.
Before any data can be written (programmed) to the EEPROM,
the EEPROM must be unlocked for write access. After it is
unlocked, the EEPROM is opened for reading, writing, and
erasing.
On power-up, Page 0 and Page 1 are also protected from read
access. The EEPROM must first be unlocked to read these pages.
Unlock the EEPROM
To unlock the EEPROM, perform two consecutive writes
with the correct password (default = 0xFF), using the
EEPROM_PASSWORD command (Register 0xD5). The
EEPROM_UNLOCKED flag (Register 0xFEA2[3]) is set to
indicate that the EEPROM is unlocked for write access.
Lock the EEPROM
To lock the EEPROM, write any byte other than the correct
password, using the EEPROM_PASSWORD command
(Register 0xD5). The EEPROM_UNLOCKED flag is cleared
to indicate that the EEPROM is locked from write access.
Change the EEPROM Password
To change the EEPROM password, first write the correct password,
using the EEPROM_PASSWORD command (Register 0xD5).
Immediately write the new password, using the same command.
The password is now changed to the new password.
Rev. A | Page 49 of 108
ADP1051 Data Sheet
DOWNLOADING EEPROM SETTINGS
TO INTERNAL REGISTERS
Download User Settings to Registers
The user settings are stored in Page 1 of the EEPROM main
block. These settings are downloaded from the EEPROM into
the registers under the following conditions:
On power-up. The user settings are automatically downloaded
into the internal registers, powering the part up in a state
previously saved by the user.
On execution of the RESTORE_USER_ALL command
(Register 0x16). This command allows the user to force a
download of the user settings from Page 1 of the EEPROM
main block into the internal registers.
Download Factory Settings to Registers
The factory default settings are stored in Page 0 of the EEPROM
main block. The factory settings can be downloaded from the
EEPROM into the internal registers, using the RESTORE_
DEFAULT_ALL command (Register 0x12).
When this command is executed, the EEPROM password is also
reset to the factory default setting of 0xFF.
SAVING REGISTER SETTINGS TO THE EEPROM
The register settings cannot be saved to the factory scratch pad
located in Page 0 of the EEPROM main block. This is to prevent
the user from accidentally overriding the factory trim settings
and the default register settings.
Save Register Settings to the User Settings
The register settings can be saved to the user settings located in
Page 1 of the EEPROM main block using the STORE_USER_ALL
command (Register 0x15). Before this command can be executed,
the EEPROM must first be unlocked for writing (see the Unlock
the EEPROM section).
After the register settings are saved to the user settings, any
subsequent power cycle automatically downloads the latest
stored user information from the EEPROM into the internal
registers.
Note that execution of the STORE_USER_ALL command
automatically performs a page erase on Page 1 of the EEPROM
main block, after which the registers are stored in the EEPROM.
Therefore, it is important to wait at least 40 ms for the operation
to complete before executing the next PMBus command.
EEPROM CRC CHECKSUM
As a simple method of checking that the values downloaded
from the EEPROM and the internal registers are consistent,
a CRC checksum is implemented.
When the data from the internal registers is saved to the
EEPROM (Page 1 of the main block), the total number of 1s
from all the registers is counted and written into the EEPROM
as the last byte of information. This is called the CRC
checksum.
When the data is downloaded from the EEPROM into the
internal registers, a similar counter is saved that sums all
1s from the values loaded into the registers. This value is
compared with the CRC checksum from the previous upload
operation.
If the values match, the download operation was successful.
If the values differ, the EEPROM download operation failed,
and the CRC_FAULT flag is set (Register 0xFEA2[2]).
To read the EEPROM CRC checksum value, execute the
EEPROM_CRC_CHKSUM command (Register 0xD1). This
command returns the CRC checksum accumulated in the counter
during the download operation.
Note that the CRC checksum is an 8-bit cyclical accumulator
that wraps around to 0 when 255 is reached.
Rev. A | Page 50 of 108
Data Sheet ADP1051
GUI SOFTWARE
Free GUI software is available for programming and configuring
the ADP1051. The ADP1051 GUI, which is intuitive by design,
dramatically reduces power supply design and development time.
The software includes filter design and power supply PWM
topology windows. The ADP1051 GUI is also an information
center, displaying the status of all readings, monitoring, and
flags on the ADP1051.
For more information about the ADP1051 GUI, contact Analog
Devices, Inc., for the latest software and a user guide. Evaluation
boards are also available by contacting Analog Devices or by
visiting http://www.analog.com/digitalpower.
11443-060
Figure 61. GUI Software
Rev. A | Page 51 of 108
ADP1051 Data Sheet
PMBus COMMAND SET
Table 11. PMBus/SMBus Command List Overview
Command
Code Command Name
PMBus/
SMBus
Transaction
Type
Number
of Data
Bytes
Default
Value1 Description
0x01 OPERATION R/W 1 0x00 Turns the unit on and off in conjunction with the input
from the CTRL pin.
0x02
ON_OFF_CONFIG
R/W
1
0x00
The combination of CTRL pin and serial bus commands
needed to turn the unit on and off.
0x03 CLEAR_FAULTS Send byte 0 N/A Clears all bits in the PMBus status registers simultaneously.
0x10 WRITE_PROTECT R/W 1 0x00 Protects against accidental writes to the PMBus device.
Reads are allowed.
0x12 RESTORE_DEFAULT_ALL Send byte 0 N/A Downloads the factory default settings from EEPROM
(Page 0) to registers.
0x15 STORE_USER_ALL Send byte 0 N/A Saves the user settings from the registers to the EEPROM
(Page 1).
0x16
RESTORE_USER_ALL
Send byte
0
N/A
Downloads the user settings from the EEPROM (Page 1) to
the registers.
0x19 CAPABILITY R 1 0x20 Allows the host system to determine the capabilities of the
PMBus device.
0x20 VOUT_MODE R 1 0x16 Sets/reads the formats for the VOUT related commands.
0x21 VOUT_COMMAND R/W 2 0x0000 Sets the VOUT to the commanded value.
0x22 VOUT_TRIM R/W 2 0x0000 Applies a fixed offset voltage to the output voltage
command value.
0x23 VOUT_CAL_OFFSET R/W 2 0x0000 Applies a fixed offset voltage to the output voltage
command value.
0x24
VOUT_MAX
R/W
2
0x0000
Sets an upper limit on the VOUT.
0x25 VOUT_MARGIN_HIGH R/W 2 0x0000 Defines the voltage to which the output is set when the
OPERATION command is set to margin high.
0x26 VOUT_MARGIN_LOW R/W 2 0x0000 Defines the voltage to which the output is set when the
OPERATION command is set to margin low.
0x27 VOUT_TRANSITION_RATE R/W 2 0x7BFF Sets the rate at which the output should change voltage.
0x28 VOUT_DROOP R/W 2 0x0000 Sets the rate at which the output voltage changes with the
output current.
0x29 VOUT_SCALE_LOOP R/W 2 0x0001 The scale factor for setting the output voltage, which is
related to the resistor divider.
0x2A VOUT_SCALE_MONITOR R/W 2 0x0001 The scale factor for the READ_VOUT command, which
typically can be the same as the VOUT_SCALE_LOOP
command.
0x33 FREQUENCY_SWITCH R/W 2 0x0031 Sets the switching frequency of the output voltage.
0x35 VIN_ON R/W 2 0x0000 Sets the input voltage at which the unit starts the power
conversion.
0x36 VIN_OFF R/W 2 0x0000 Sets the input voltage at which the unit stops the power
conversion.
0x38 IOUT_CAL_GAIN R/W 2 0x0000 The scale factor for the READ_IOUT command.
0x40 VOUT_OV_FAULT_LIMIT R/W 2 0x0000 Sets the limit for triggering the OV_FAULT flag.
0x41 VOUT_OV_FAULT_RESPONSE R/W 1 0x00 The fault response for the OV_FAULT flag.
0x44 VOUT_UV_FAULT_LIMIT R/W 2 0x0000 Sets the limit for triggering the VOUT_UV_FAULT flag.
0x45 VOUT_UV_FAULT_RESPONSE R/W 1 0x00 The fault response for the VOUT_UV_FAULT flag.
0x46
IOUT_OC_FAULT_LIMIT
R/W
2
0x0000
Sets the limit for triggering the OC_FAULT flag.
0x47 IOUT_OC_FAULT_RESPONSE R/W 1 0x00 The fault response for the OC_FAULT flag.
0x48 IOUT_OC_LV_FAULT_LIMIT R/W 2 0x0000 Sets the voltage threshold in cases for which the response
to an overcurrent condition is to operate in a constant
current mode unless the output voltage is pulled below
the specified limit value.
Rev. A | Page 52 of 108
Data Sheet ADP1051
Command
Code Command Name
PMBus/
SMBus
Transaction
Type
Number
of Data
Bytes
Default
Value1 Description
0x4F OT_FAULT_LIMIT R/W 2 0x0000 Sets the limit for triggering the OT_FAULT flag.
0x50 OT_FAULT_RESPONSE R/W 1 0x00 The fault response for the OT_FAULT flag.
0x5E POWER_GOOD_ON R/W 2 0x0000 Sets the output voltage at which an optional POWER_GOOD
signal is asserted.
0x5F POWER_GOOD_OFF R/W 2 0x0000 Sets the output voltage at which an optional POWER_GOOD
signal is negated.
0x60 TON_DELAY R/W 2 0x0000 The time from when a start condition is received (as
programmed by the ON_OFF_CONFIG command) until the
output voltage starts to rise.
0x61
TON_RISE
R/W
2
0xC00D
The time from when the output starts to rise until the
voltage has entered the regulation band.
0x64 TOFF_DELAY R/W 2 0x0000 The time from when a stop condition is received (as
programmed by the ON_OFF_CONFIG command) until the
unit stops transferring energy to the output.
0x78 STATUS_BYTE R 1 0x00 Returns the low byte of the STATUS_WORD command.
0x79 STATUS_WORD R 2 0x0000 Returns the low byte and high byte of the STATUS_WORD
command.
0x7A
STATUS_VOUT
R
1
0x00
Returns the fault flag for the output voltage.
0x7B STATUS_IOUT R 1 0x00 Returns the fault flag for the output current.
0x7C STATUS_INPUT R 1 0x00 Returns the fault flag for the input voltage and current.
0x7D STATUS_TEMPERATURE R 1 0x00 Returns the fault flag for the OT fault and warning.
0x7E
STATUS_CML
R
1
0x00
Returns the fault flag for the communication memory and
logic.
0x88 READ_VIN R 2 0x0000 Returns the input voltage value.
0x89 READ_IIN R 2 0x0000 Returns the input current value.
0x8B READ_VOUT R 2 0x0000 Returns the output voltage value.
0x8C READ_IOUT R 2 0x0000 Returns the output current value.
0x8D READ_TEMPERATURE R 2 0x0000 Returns temperature reading in degrees Celsius.
0x94 READ_DUTY_CYCLE R 2 0x0000 Returns the duty cycle of the power converter.
0x95 READ_FREQUENCY R 2 0x0000 Returns the switching frequency of the power converter.
0x98 READ_PMBUS_REVISION R 1 0x22 Reads the PMBus revision to which the device is compliant.
0x99 MFR_ID R/W 1 0x00 Reads/writes the ID of the manufacturer.
0x9A MFR_MODEL R/W 1 0x00 Reads/writes the model number of the manufacturer.
0x9B MFR_REVISION R/W 1 0x00 Reads/writes revision number of the manufacturer.
0xAD IC_DEVICE_ID R 2 0x4151 Reads the IC device ID.
0xAE IC_DEVICE_REV R 1 0x20 Reads the IC device revision.
0xB0 EEPROM_DATA_00 R block Variable N/A Block reads from Page 0. The EEPROM must first be unlocked.
0xB1 EEPROM_DATA_01 R block Variable N/A Block reads from Page 1. The EEPROM must first be unlocked.
0xB2 EEPROM_DATA_02 R/W block Variable N/A Blocks reads/writes to Page 2. The EEPROM must first be
unlocked for writes.
0xB3 EEPROM_DATA_03 R/W block Variable N/A Blocks reads/writes to Page 3. The EEPROM must first be
unlocked for writes.
0xB4 EEPROM_DATA_04 R/W block Variable N/A Blocks reads/writes to Page 4. The EEPROM must first be
unlocked for writes.
0xB5 EEPROM_DATA_05 R/W block Variable N/A Blocks reads/writes to Page 5. The EEPROM must first be
unlocked for writes.
0xB6
EEPROM_DATA_06
R/W block
Variable
N/A
Blocks reads/writes to Page 6. The EEPROM must first be
unlocked for writes.
0xB7 EEPROM_DATA_07 R/W block Variable N/A Blocks reads/writes to Page 7. The EEPROM must first be
unlocked for writes.
0xB8 EEPROM_DATA_08 R/W block Variable N/A Blocks reads/writes to Page 8. The EEPROM must first be
unlocked for writes.
Rev. A | Page 53 of 108
ADP1051 Data Sheet
Command
Code Command Name
PMBus/
SMBus
Transaction
Type
Number
of Data
Bytes
Default
Value1 Description
0xB9 EEPROM_DATA_09 R/W block Variable N/A Blocks reads/writes to Page 9. The EEPROM must first be
unlocked for writes.
0xBA EEPROM_DATA_10 R/W block Variable N/A Blocks reads/writes to Page 10. The EEPROM must first be
unlocked for writes.
0xBB EEPROM_DATA_11 R/W block Variable N/A Blocks reads/writes to Page 11. The EEPROM must first be
unlocked for writes.
0xBC EEPROM_DATA_12 R/W block Variable N/A Blocks reads/writes to Page 12. The EEPROM must first be
unlocked for writes.
0xBD EEPROM_DATA_13 R/W block Variable N/A Blocks reads/writes to Page 13. The EEPROM must first be
unlocked for writes.
0xBE
EEPROM_DATA_14
R/W block
Variable
N/A
Blocks reads/writes to Page 14. The EEPROM must first be
unlocked for writes.
0xBF EEPROM_DATA_15 R/W block Variable N/A Blocks reads/writes to Page 15. The EEPROM must first be
unlocked for writes.
0xD1 EEPROM_CRC_CHKSUM R 1 N/A Returns the CRC checksum value from the EEPROM
download operation.
0xD2
EEPROM_NUM_RD_BYTES
R/W
1
N/A
Sets the number of return read bytes when using
EEPROM_DATA_xx commands.
0xD3 EEPROM_ADDR_OFFSET R/W 2 N/A Sets the address offset of the current EEPROM page.
0xD4 EEPROM_PAGE_ERASE W 1 N/A Performs a page erase on a selected page (Page 3 to Page 15).
Wait 35 ms for each page erase operation. The EEPROM
must first be unlocked. A page erase of Page 0 and Page 1
is not allowed.
0xD5 EEPROM_PASSWORD W 1 0xFF Writes the password to this register to unlock the EEPROM,
and/or changes the EEPROM password.
0xD6 TRIM_PASSWORD W 1 0xFF Writes the password to this register to unlock the trim
registers for write access.
0xD7 CHIP_PASSWORD W 2 0xFFFF Writes the password to this register to unlock the chip
password for register access.
0xD8
VIN_SCALE_MONITOR
R/W
2
0x0001
The scale factor for the input voltage reading (READ_VIN).
0xD9 IIN_SCALE_MONITOR R/W 2 0x0001 The scale factor for the input current reading (READ_IIN).
0xF1 EEPROM_INFO Read block Variable N/A Reads the first fault information.
0xFA MFR_SPECIFIC_1 R/W 1 0x00 Stores the user customized information. This register also
stores the CS2 high-side mode factory analog trim value.
0xFB MFR_SPECIFIC_2 R/W 1 0x00 Stores the user customized information test. This register
also stores the CS2 high-side mode digital offset trim value.
1 N/A = Not applicable.
Rev. A | Page 54 of 108
Data Sheet ADP1051
MANUFACTURER SPECIFIC EXTENDED COMMAND LIST
Table 12. Manufacturer Specific Extended Command List Overview
Address Register Function
Flag Configuration Registers
0xFE00 IIN_OC_FAST_FAULT_RESPONSE
0xFE01 CS3_OC_FAULT_RESPONSE, extended VOUT_OV_FAULT_RESPONSE
0xFE02 VIN_UV_FAULT_RESPONSE
0xFE03 FLAGIN_RESPONSE, SR_RC_FAULT_RESPONSE
0xFE05 Flag reenable delay, VDD_OV_RESPONSE
Soft Start Software Reset Setting Registers
0xFE06 Software reset GO command
0xFE07 Software reset settings
0xFE08 Synchronous rectifier (SR) soft start settings
0xFE09 Soft start setting of open-loop operation
Blanking and PGOOD Setting Registers
0xFE0B Flag blanking during soft start
0xFE0C Volt-second balance blanking and SR disable during soft start
0xFE0D PGOOD mask settings
0xFE0E PGOOD flag debounce
0xFE0F Debounce time for asserting PGOOD
Switching Frequency and Synchronization Setting Registers
0xFE11 Synchronization delay time
0xFE12 Synchronization general settings
0xFE13 Dual-ended topology mode
Current Sense and Limit Setting Registers
0xFE14 CS1 gain trim
0xFE15 CS2 gain trim
0xFE16 CS2 digital offset trim
0xFE17
CS2 analog trim
0xFE19 CS2 light load threshold
0xFE1A IIN_OC_FAST_FAULT_LIMIT and SR_RC_FAULT_LIMIT
0xFE1B CS2 deep light load mode setting
0xFE1C PWM outputs disable at deep light load mode
0xFE1D Matched cycle-by-cycle current-limit settings
0xFE1E Light load mode and deep light mode settings
0xFE1F CS1 cycle-by-cycle current-limit settings
Voltage Sense and Limit Setting Registers
0xFE20 VS gain trim
0xFE25 Pre-bias start-up enable
0xFE26 VOUT_OV_FAULT flag debounce
0xFE28 VF gain trim
0xFE29 VIN_ON and VIN_OFF delay
Temperature Sense and Protection Setting Registers
0xFE2A RTD gain trim
0xFE2B RTD offset trim (MSBs)
0xFE2C RTD offset trim (LSBs)
0xFE2D RTD current source settings
0xFE2F OT hysteresis settings
Rev. A | Page 55 of 108
ADP1051 Data Sheet
Address Register Function
Digital Compensator and Modulation Setting Registers
0xFE30 Normal mode compensator low frequency gain settings
0xFE31 Normal mode compensator zero settings
0xFE32 Normal mode compensator pole settings
0xFE33 Normal mode compensator high frequency gain settings
0xFE34
Light load mode compensator low frequency gain settings
0xFE35
Light load mode compensator zero settings
0xFE36 Light load mode compensator pole settings
0xFE37 Light load mode compensator high frequency gain settings
0xFE38 CS1 threshold for volt-second balance
0xFE39 Nominal modulation value for pre-bias startup
0xFE3A Constant current speed and SR driver delay
0xFE3B PWM 180° phase shift settings
0xFE3C Modulation limit
0xFE3D Feedforward and soft start filter gain
PWM Outputs Timing Registers
0xFE3E OUTA rising edge timing
0xFE3F OUTA falling edge timing
0xFE40 OUTA rising and falling edges timing (LSBs)
0xFE41 OUTB rising edge timing
0xFE42 OUTB falling edge timing
0xFE43 OUTB rising and falling edges timing (LSBs)
0xFE44 OUTC rising edge timing
0xFE45 OUTC falling edge timing
0xFE46 OUTC rising and falling edges timing (LSBs)
0xFE47 OUTD rising edge timing
0xFE48 OUTD falling edge timing
0xFE49
OUTD rising and falling edges timing (LSBs)
0xFE4A SR1 rising edge timing
0xFE4B SR1 falling edge timing
0xFE4C SR1 rising and falling edges timing (LSBs)
0xFE4D SR2 rising edge timing
0xFE4E SR2 falling edge timing
0xFE4F SR2 rising and falling edges timing (LSBs)
0xFE50 OUTA and OUTB modulation settings
0xFE51 OUTC and OUTD modulation settings
0xFE52 SR1 and SR2 modulation settings
0xFE53 PWM output disable
Volt-Second Balance Control Registers
0xFE54 Volt-second balance control general settings
0xFE55 Volt-second balance control on OUTA and OUTB
0xFE56 Volt-second balance control on OUTC and OUTD
0xFE57 Volt-second balance control on SR1 and SR2
Duty Cycle Setting Registers
0xFE58 Duty cycle reading settings
0xFE59 Input voltage compensation multiplier
Adaptive Dead Time Compensation Registers
0xFE5A Adaptive dead time compensation threshold
0xFE5B OUTA dead time
0xFE5C OUTB dead time
0xFE5D OUTC dead time
0xFE5E OUTD dead time
0xFE5F SR1 dead time
0xFE60 SR2 dead time
Rev. A | Page 56 of 108
Data Sheet ADP1051
Address Register Function
Other Setting Registers
0xFE61 GO commands
0xFE62 Customized register
0xFE63 Modulation reference MSBs setting for open-loop input voltage feedforward operation
0xFE64 Modulation reference LSBs setting for open-loop input voltage feedforward operation
0xFE65
Current value update rate setting
0xFE66
Adaptive dead time compensation configuration
0xFE67 Open-loop operation settings
0xFE68 Offset setting for SR1 and SR2
0xFE69 Pulse skipping mode threshold
0xFE6A CS3_OC_FAULT_LIMIT
0xFE6B Modulation threshold for OVP selection
0xFE6C Modulation flag for OVP selection
0xFE6D OUTA and OUTB adjustment reference during synchronization
0xFE6E OUTC and OUTD adjustment reference during synchronization
0xFE6F SR1 and SR2 adjustment reference during synchronization
Manufacturer Specific Fault Flag Registers
0xFEA0 Flag Register 1
0xFEA1 Flag Register 2
0xFEA2 Flag Register 3
0xFEA3 Latched Flag Register 1
0xFEA4 Latched Flag Register 2
0xFEA5 Latched Flag Register 3
0xFEA6 First flag ID
Manufacturer Specific Value Reading Registers
0xFEA7 CS1 value
0xFEA8 CS2 value
0xFEA9 CS3 value
0xFEAA VS value
0xFEAB RTD value
0xFEAC
VF value
0xFEAD Duty cycle value
0xFEAE Input power value
0xFEAF Output power value
Rev. A | Page 57 of 108
ADP1051 Data Sheet
PMBus COMMAND DESCRIPTIONS
BASIC PMBus COMMANDS
OPERATION
The OPERATION command is used to turn the unit on and off in conjunction with the input from the CTRL pin. It is also used to set the
output voltage to the upper or lower voltage margin. The unit stays in the commanded operating mode until a subsequent OPERATION
command instructs the device to change to another mode.
Table 13. Register 0x01—OPERATION
Bits Bit Name/Function R/W Description
[7:6] Enable R/W These bits determine the response to the OPERATION command.
Bit 7 Bit 6 Description
0 0 Immediate off (no sequencing)
0 1 Soft off (power-down based on the programmed TOFF_DELAY command)
1 0 Unit on
1 1 Reserved
[5:4] Margin control R/W These bits set the voltage margin level.
Bit 5 Bit 4 Description
0 0 Off
0 1 Margin low
1 0 Margin high
1 1 Reserved
[3:0]
Reserved
R
Reserved.
ON_OFF_CONFIG
The ON_OFF_CONFIG command configures the combination of CTRL pin input and serial bus commands needed to turn the unit on and off,
including how the unit responds when power is applied.
Table 14. Register 0x02—ON_OFF_CONFIG
Bits Bit Name/Function R/W Description
[7:5] Reserved R Reserved.
4 Power-up control R/W Controls how the device responds to the OPERATION command.
0 = the unit powers up whenever power is present.
1 = the unit powers up only when commanded by the CTRL pin and the OPERATION command
(as programmed in Register 0x02, Bits[3:0]).
3 Command enable R/W Controls how the device responds to the OPERATION command.
0 = ignores the OPERATION command.
1 = requires that the OPERATION command be set to the on state to enable the unit (in addition to
the setting of Bit 2).
2 Pin enable R/W Controls how the device responds to the value on the CTRL pin.
0 = ignores the CTRL pin.
1 = requires the CTRL pin to be asserted to enable the unit (in addition to the setting of Bit 3).
1 CTRL pin polarity R/W Sets the polarity for the CTRL pin.
0 = active low.
1 = active high.
0 Power-down delay
setting
R/W Action to take at power-down.
0 = uses the TOFF_DELAY value (TOFF_FALL is not supported by the ADP1051) to stop the
transfer of energy to the output.
1 = turns off the output and stops energy transfer to the output as fast as possible.
CLEAR_FAULTS
The CLEAR_FAULTS command is a send byte, no data. This command clears all PMBus fault bits in all PMBus status registers simultaneously.
Table 15. Register 0x03—CLEAR_FAULTS
Bits Bit Name/Function Type Description
N/A CLEAR_FAULTS Send Clears all bits in PMBus status registers (Register 0x78 to Register 0x7E) simultaneously.
Rev. A | Page 58 of 108
Data Sheet ADP1051
WRITE_PROTECT
The WRITE_PROTECT command is used to control writing to the PMBus device. The intent of this command is to provide protection
against accidental changes. This command is not intended to provide protection against deliberate or malicious changes to the
configuration or operation of the device.
Table 16. Register 0x10—WRITE_PROTECT
Bits Bit Name/Function R/W Description
7 Write Protect 1 R/W Disables writes to all commands except the WRITE_PROTECT command.
6 Write Protect 2 R/W Disables writes to all commands except the WRITE_PROTECT and OPERATION commands.
5 Write Protect 3 R/W Disables writes to all commands except the WRITE_PROTECT, OPERATION, ON_OFF_CONFIG, and
VOUT_COMMAND commands.
[4:0] Reserved R Reserved.
RESTORE_DEFAULT_ALL
The RESTORE_DEFAULT_ALL command is a send byte, no data. This command downloads the factory default settings (including the
basic PMBus commands, the manufacturer specific extended commands (starting with 0xFE), and other data such as the checksum, the
EEPROM password, and the chip password) from the EEPROM (Page 0 of the main block) into the registers.
Table 17. Register 0x12—RESTORE_DEFAULT_ALL
Bits Bit Name/Function Type Description
N/A RESTORE_DEFAULT_ALL Send Restores the factory default settings from the EEPROM to the registers.
STORE_USER_ALL
The STORE_USER_ALL command is a send byte, no data. This command copies the entire contents of the registers into the EEPROM
(Page 1 of the main block) as the user settings. The settings are automatically restored on the power-up of VDD.
Table 18. Register 0x15—STORE_USER_ALL
Bits Bit Name/Function Type Description
N/A STORE_USER_ALL Send Saves the user settings from the registers to the EEPROM.
RESTORE_USER_ALL
The RESTORE_USER_ALL command is a send byte, no data. This command downloads the stored user settings including the basic
PMBus commands, the manufacturer specific extended commands (starting with 0xFE), and other data (for example, the checksum, the
EEPROM password, and the chip password) from the EEPROM (Page 1 of the main block) into the registers.
Table 19. Register 0x16—RESTORE_USER_ALL
Bits Bit Name/Function Type Description
N/A
RESTORE_USER_ALL
Send
Restores the user settings from the EEPROM to the registers.
CAPABILITY
This command summarizes the PMBus optional communication protocols supported by the ADP1051. The reading of this command
should result in 0x20.
Table 20. Register 0x19—CAPABILITY
Bits
Bit Name/Function
R/W
Description
[7] Packet error R Checks the packet error capability of the device.
0 = not supported.
[6:5] Maximum bus speed R Checks the PMBus speed capability of the device.
01 = maximum bus speed of 400 kHz.
4 SMBALERT R Checks support of the SMBALERT pin and the SMBus alert response protocol.
0 = not supported.
[3:0] Reserved R Reserved.
Rev. A | Page 59 of 108
ADP1051 Data Sheet
VOUT_MODE
The VOUT_MODE command sets the data format for output voltage related data. The data byte for the VOUT_MODE command consists of
a 3-bit mode and 5-bit exponent parameter. The 3-bit mode determines whether the device uses linear format or direct format for the output
voltage related commands. The 5-bit parameter sets the exponent value for linear format.
Table 21. Register 0x20—VOUT_MODE
Bits Bit Name/Function R/W Description
[7:5] Mode R Output voltage data format. The value is fixed at 000, which means that only linear format is
supported.
[4:0]
Exponent
R
The N value for the output voltage related commands in linear format: V = Y × 2
N
.
The value is fixed at 10110 (twos complement, −10 decimal). The exponent for linear format
values is −10.
VOUT_COMMAND
The VOUT_COMMAND command sets the output voltage. The VOUT_TRANSITION_RATE command is used if this command is
modified while the output is active and in a steady state condition. The maximum programmable output voltage is 64 V.
Table 22. Register 0x21—VOUT_COMMAND
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the output voltage reference value, in volts.
16-bit unsigned integer Y value for linear format: V = Y × 2N.
N is defined in the VOUT_MODE command.
VOUT_TRIM
The VOUT_TRIM command applies a fixed offset voltage to the output voltage command value. It is typically set by the user to trim the
output voltage at the time that the PMBus device is assembled into the system of the user. The trim range is −32 V to +32 V, and each LSB
resolution is 2−10 = 0.9765625 mV.
Table 23. Register 0x22—VOUT_TRIM
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the output voltage trim value.
16-bit twos complement Y value for linear format: V = Y × 2N.
N is defined in the VOUT_MODE command.
VOUT_CAL_OFFSET
The VOUT_CAL_OFFSET command is used to apply a fixed offset voltage to the output voltage command value. It is typically used by the
PMBus device manufacturer to calibrate the device in the factory. The trim range is −32 V to +32 V and each LSB size is 2−10 = 0.9765625 mV.
Table 24. Register 0x23—VOUT_CAL_OFFSET
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the output voltage trim value.
16-bit twos complement Y value for linear format: V = Y × 2N.
N is defined in the VOUT_MODE command.
VOUT_MAX
The VOUT_MAX command sets an upper limit on the output voltage the unit can attain, regardless of any other commands or combinations.
If an attempt is made to program the output voltage higher than the limit set by this command, the device responds as follows:
The commanded output voltage is set to the VOUT_MAX value.
The NONE OF THE ABOVE bit is set in the STATUS_BYTE command (Register 0x78[0]).
The VOUT bit is set in the STATUS_WORD command (Register 0x79[15]).
The VOUT_MAX warning bit is set in the STATUS_VOUT command (Register 0x7A[3]).
Table 25. Register 0x24—VOUT_MAX
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the output voltage upper limit.
16-bit unsigned integer Y value for linear format: V = Y × 2N.
N is defined in the VOUT_MODE command.
Rev. A | Page 60 of 108
Data Sheet ADP1051
Rev. A | Page 61 of 108
VOUT_MARGIN_HIGH
The VOUT_MARGIN_HIGH command sets the target voltage to which the output changes when the OPERATION command is set to
margin high. The VOUT_TRANSITION_RATE command is used if this command is modified while the output is active and in a steady-
state condition.
Table 26. Register 0x25—VOUT_MARGIN_HIGH
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the margin high value for the output voltage, in volts.
16-bit unsigned integer Y value for linear format: V = Y × 2N.
N is defined by the VOUT_MODE command.
VOUT_MARGIN_LOW
The VOUT_MARGIN_LOW command sets the target voltage, to which the output changes when the OPERATION command is set to
margin low. The VOUT_TRANSITION_RATE command is used if this command is modified while the output is active and in a steady-
state condition.
Table 27. Register 0x26—VOUT_MARGIN_LOW
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the margin low value for the output voltage, in volts.
16-bit unsigned integer Y value for linear format V = Y × 2N.
N is defined by the VOUT_MODE command.
3:1
MUX LIMITER
VOUT_MAX
OPERATION
COMMAND
VOUT_MARGIN_HIGH
VOUT_MARGIN_LOW
VOUT_TRIM
VOUT_CAL_OFFSET
VOUT_DROOP IOUT
VOUT_COMMAND VOUT_
SCALE_
LOOP
REFERENCE
VOLTAGE
EQUIVALENT
11443-061
Figure 62. Conceptual View of the Output Voltage Related Commands
VOUT_TRANSITION_RATE
When the part receives either a VOUT_COMMAND command or an OPERATION command (margin high, margin low) that causes the
output voltage to change, this command sets the rate, in mV/μs, at which the VS± pins change voltage. This commanded rate of change does
not apply when the unit is turned on or off. The maximum positive value (0x7BFF) of the two data bytes indicates that the unit makes the
transition as quickly as possible. Only the following limited options are supported by the ADP1051.
Table 28. Register 0x27—VOUT_TRANSITION_RATE (Rate-of-Change Options Supported by the ADP1051)
Register Setting Rate of Change (mV/μs)
1001100000001101 (0x980D) 0.0015625
1010000000001101 (0xA00D) 0.003125
1010100000001101 (0xA80D) 0.00625
1011000000001101 (0xB00D) 0.0125
1011100000001101 (0xB80D) 0.025
1100000000001101 (0xC00D) 0.050
1100100000001101 (0xC80D) 0.1
1101000000001101 (0xD00D) 0.2
0111101111111111 (0x7BFF) Infinite (default)
Table 29. Register 0x27—VOUT_TRANSITION_RATE
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
ADP1051 Data Sheet
VOUT_DROOP
The VOUT_DROOP command sets the rate, in mV/A (mΩ), at which the output voltage decreases (or increases) with increasing (or decreasing)
output current for use with the adaptive voltage positioning requirements and passive current sharing schemes. The range of VOUT_DROOP
in the ADP1051 is 0x0000 to 0x00FF (0 mΩ to 255 mΩ). Values not within this range are invalid. An invalid value results in a CML error.
Table 30. Register 0x28—VOUT_DROOP
Bits Bit Name/Function R/W Description
[15:11] Exponent R 5-bit twos complement N value for linear format X = Y × 2N. N is fixed at 0.
[10:8] Mantissa high bits R Mantissa high bits, Y[10:8], value fixed at 0.
[7:0] Mantissa low bits R/W Mantissa low bits, Y[7:0], value for linear format X = Y × 2N.
VOUT_SCALE_LOOP
The VOUT_SCALE_LOOP command is equal to the feedback resistor ratio. The nominal output voltage is set by a resistor divider and
the internal 1 V reference voltage. For example, if the nominal output voltage is 12 V, the VOUT_SCALE_LOOP value = 1 V/12 V =
0.08333 and the VOUT_SCALE_LOOP can be set as 0xA155.
Table 31. Register 0x29—VOUT_SCALE_LOOP
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format KR = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format KR = Y × 2N.
VOUT K
R
RESISTOR
DIVIDER
RATIO
ERROR
PROCESSING/
CONTROL LOOP
PMBu s DE V ICE
VOUT_
SCALE_
LOOP
VOUT_COMMAND K
16
11443-062
Figure 63. Conceptual View of the VOUT_SCALE_LOOP Command
VOUT_SCALE_MONITOR
This command is typically the same as the VOUT_SCALE_LOOP command. It is used for reading the output voltage with the READ_VOUT
command (Register 0x8B).
Table 32. Register 0x2A—VOUT_SCALE_MONITOR
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format KR = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format KR = Y × 2N.
Rev. A | Page 62 of 108
Data Sheet ADP1051
FREQUENCY_SWITCH
The FREQUENCY_SWITCH command, which sets the switching frequency in kHz, is in linear format. Only the following limited switching
frequency options are supported by the ADP1051. In the ADP1051, because the switching frequency is calculated from the switching period, the
switching period value that is used is an accurate measure, whereas the switching frequency may not be. For example, for the first
switching frequency option of 49 kHz (see Tabl e 33), the actual switching frequency is calculated by 1/(20.48 µs) = 48.828125 kHz, which
is simplified (rounded) to 49 kHz.
To avoid an incorrect switching frequency setting, the GO commands in Register 0xFE61[2:1] must be used to latch this setting and the
PWM setting.
Table 33. Register 0x33—FREQUENCY_SWITCH (Options Supported by the ADP1051)
Register Setting Switching Frequency (kHz) Accurate Switching Period (µs)
0000000000110001 (0x0031) 49 20.48
0000000000111000 (0x0038) 56 17.92
0000000000111100 (0x003C)
60
16.64
0000000001000001 (0x0041) 65 15.36
0000000001000111 (0x0047) 71 14.08
0000000001001110 (0x004E) 78 12.80
0000000001010111 (0x0057) 87 11.52
1111100011000011 (0xF8C3) 97.5 10.24
0000000001101000 (0x0068) 104 9.60
1111100011011111 (0xF8DF) 111.5 8.96
0000000001111000 (0x0078) 120 8.32
0000000010000010 (0x0082) 130 7.68
0000000010001000 (0x0088) 136 7.36
0000000010001110 (0x008E)
142
7.04
0000000010010101 (0x0095) 149 6.72
1111100100111001 (0xF939) 156.5 6.40
1111100101001001 (0xF949) 164.5 6.08
1111100101011011 (0xF95B) 173.5 5.76
0000000010111000 (0x00B8) 184 5.44
1111100110000111 (0xF987) 195.5 5.12
1111100110010011 (0xF993) 201.5 4.96
1111100110100001 (0xF9A1) 208.5 4.80
1111100110101111 (0xF9AF) 215.5 4.64
0000000011011111 (0xDF) 223 4.48
1111100111001111 (0xF9CF) 231.5 4.32
1111100111100001 (0xF9E1) 240.5 4.16
0000000011111010 (0x00FA) 250 4.00
1111101000001001 (0xFA09) 260.5 3.84
1111101000011111 (0xFA1F) 271.5 3.68
0000000100011100 (0x011C) 284 3.52
1111101001010011 (0xFA53)
297.5
3.36
1111101001110001 (0xFA71) 312.5 3.20
1111101010000001 (0xFA81) 320.5 3.12
0000000101001001 (0x0149) 329 3.04
0000000101010010 (0x0152) 338 2.96
0000000101011011 (0x15B) 347 2.88
0000000101100101 (0x0165) 357 2.80
1111101011011111 (0xFADF) 367.5 2.72
0000000101111011 (0x017B) 379 2.64
1111101100001101 (0xFB0D) 390.5 2.56
0000000110001101 (0x018D) 397 2.52
0000000110010011 (0x0193)
403
2.48
0000000110011010 (0x019A) 410 2.44
Rev. A | Page 63 of 108
ADP1051 Data Sheet
Register Setting Switching Frequency (kHz) Accurate Switching Period (µs)
1111101101000001 (0xFB41) 416.5 2.40
1111101101001111 (0xFB4F) 423.5 2.36
0000000110101111 (0x1AF) 431 2.32
1111101101101101 (0xFB6D) 438.5 2.28
1111101101111101 (0xFB7D)
446.5
2.24
1111101110001101 (0xFB8D) 454.5 2.20
0000000111001111 (0x01CF) 463 2.16
0000000111011000 (0x01D8) 472 2.12
0000000111100001 (0x01E1) 481 2.08
0000000111101010 (0x1EA) 490 2.04
0000000111110100 (0x1F4)
500
2.00
0000000111111110 (0x01FE) 510 1.96
0000001000001000 (0x0208) 520 1.92
0000001000010011 (0x0213) 531 1.88
0000001000011111 (0x0x21F) 543 1.84
0000001000101100 (0x022C) 556 1.80
0000001000111000 (0x0238) 568 1.76
0000001001000101 (0x0245) 581 1.72
0000001001010011 (0x0253) 595 1.68
0000001001100010 (0x0262) 610 1.64
0000001001110001 (0x0271) 625 1.60
Table 34. Register 0x33—FREQUENCY_SWITCH
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
VIN_ON
The VIN_ON command sets the value of the input voltage (in volts) at which the unit starts power conversion.
Table 35. Register 0x35—VIN_ON
Bit Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
VIN_OFF
The VIN_OFF command sets the value of the input voltage (in volts) at which the unit stops power conversion after operation has started.
Table 36. Register 0x36—VIN_OFF
Bit Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
Rev. A | Page 64 of 108
Data Sheet ADP1051
IOUT_CAL_GAIN
The IOUT_CAL_GAIN command sets the ratio of the voltage at the current sense element to the sensed current. For devices using a
fixed current sense resistor, it is typically the same value as the conductance of the resistor. The units are milliohms (mΩ). Typically, this
command is used with the READ_IOUT command.
Table 37. Register 0x38—IOUT_CAL_GAIN
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0]
Mantissa
R/W
11-bit twos complement Y value for linear format X = Y × 2N.
R
SENSE
V
MEASURED
(I
OUT
)
READ_IOUT
IOUT_CAL_GAIN
I
OUT
+
–ADC
11443-063
Figure 64. Conceptual View of the Output Current Related Commands
VOUT_OV_FAULT_LIMIT
The VOUT_OV_FAULT_LIMIT command sets the threshold value for overvoltage protection of the output voltage.
Table 38. Register 0x40—VOUT_OV_FAULT_LIMIT
Bits Bit Name/Function R/W Description
[15:0]
Mantissa
R/W
16-bit unsigned integer Y value for linear mode format X = Y × 2N.
N is defined by the VOUT_MODE command.
Note that the available OV protection limit value must be in the range of 75% to 150% of the
nominal output voltage.
VOUT_OV_FAULT_RESPONSE
Table 39. Register 0x41—VOUT_OV_FAULT_RESPONSE
Bits Bit Name/Function R/W Description
[7:6]
Response
R/W
00 = continues operation without interruption.
01 = continues operation for the debounce time (Delay Time 1) specified by Register 0xFE26[7:6]. If
the fault persists, retry the number of times specified by the retry setting of this command (Bits[5:3]).
10 = shuts down and responds according to the retry setting in Bits[5:3].
11 = the output is disabled while the fault is present. Operation resumes and the output is enabled
when the fault condition no longer exists.
[5:3] Retry setting R/W 000 = restart not attempted. The output remains disabled until the fault is cleared.
001 to 110 = attempts to restart the number of times set by these bits. If the ADP1051 fails to restart
in the allowed number of retries, the output is disabled and remains off until the fault is cleared. The
time between the start of each attempt to restart is set by the Delay Time 2 value in Bits[2:0], along
with the delay time unit specified for that particular fault.
111 = attempts to restart continuously, without limitation, until it is commanded off (by the CTRL pin
or the OPERATION command, or both), VDD is removed, or another fault condition causes the unit to
shut down.
[2:0] Delay time R/W These bits set the delay time between the start of each attempt to restart.
Bit 2 Bit 1 Bit 0 Delay Time 2 (ms)
0
0
0
252
0 0 1 588
0 1 0 924
0 1 1 1260
1 0 0 1596
1 0 1 1932
1 1 0 2268
1 1 1 2604
Rev. A | Page 65 of 108
ADP1051 Data Sheet
VOUT_UV_FAULT_LIMIT
The VOUT_UV_FAULT_LIMIT command sets the threshold value for undervoltage protection of the output voltage.
Table 40. Register 0x44—VOUT_UV_FAULT_LIMIT
Bits Bit Name/Function R/W Bit Name/Function
[15:0] Mantissa R/W 16-bit unsigned integer Y value for linear format X = Y × 2N.
N is defined by the VOUT_MODE command.
VOUT_UV_FAULT_RESPONSE
Table 41. Register 0x45—VOUT_UV_FAULT_RESPONSE
Bits Bit Name/Function R/W Description
[7:6] Response R/W 00 = continues operation without interruption.
01 = continues operation for the Delay Time 1 (Bits[2:0]). If the fault persists, retry the number of
times specified by the retry setting (Bits[5:3]).
10 = shuts down (disables the output) and responds according to the retry setting in Bits[5:3].
11 = the output is disabled while the fault is present. Operation resumes and the output is enabled
when the fault condition no longer exists.
[5:3] Retry setting R/W 000 = restart not attempted. The output remains disabled until the fault is cleared.
001 to 110 = attempts to restart the number of times set by these bits. If the unit fails to restart in
the allowed number of retries, it disables the output and remains off until the fault is cleared. The time
between the start of each attempt to restart is set by the Delay Time 2 value in Bits[2:0], together
with the delay time unit specified for that particular fault.
111 = attempts to restart continuously, without limitation, until it is commanded off (by the CTRL pin
or the OPERATION command, or both), VDD is removed, or another fault condition causes the unit to
shut down.
[2:0] Delay time R/W These bits set the delay time for the VOUT_UV_FAULT_RESPONSE Delay Time 1 and Delay Time 2 as
described in Bits[7:6] and Bits[5:3].
Bit 2 Bit 1 Bit 0 Delay Time 1 (ms) Delay Time 2 (ms)
0 0 0 0 252
0 0 1 20 588
0 1 0 40 924
0 1 1 80 1260
1 0 0 160 1596
1 0 1 320 1932
1 1 0 640 2268
1
1
1
1280
2604
Rev. A | Page 66 of 108
Data Sheet ADP1051
IOUT_OC_FAULT_LIMIT
The IOUT_OC_FAULT_LIMIT command sets the threshold value for overcurrent protection of the output voltage.
Table 42. Register 0x46—IOUT_OC_FAULT_LIMIT
Bit Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
IOUT_OC_FAULT_RESPONSE
Table 43. Register 0x47—IOUT_OC_FAULT_RESPONSE
Bit Bit Name/Function R/W Description
[7:6] Response R/W 00 = operates in current-limit mode, maintaining the output current at the IOUT_OC_FAULT_LIMIT,
regardless of the output voltage (known as the constant current).
01 = operates in current-limit mode, maintaining the output current at the IOUT_OC_FAULT_LIMIT
for as long as the output voltage remains above the IOUT_OC_LV_FAULT_LIMIT. If the output
voltage is pulled down to less than that value, the ADP1051 shuts down and responds according
to the retry setting in Bits[5:3].
10 = continues operation in current-limit mode for the Delay Time 1 set by Bits[2:0], regardless of
the output voltage. If the ADP1051 is still operating in current limit at the end of the delay time, it
responds as programmed by the retry setting in Bits[5:3].
11 = shuts down and responds as programmed by the retry setting in Bits[5:3].
[5:3]
Retry setting
R/W
000 = restart not attempted. The output remains disabled until the fault is cleared.
001 to 110 = attempts to restart the number of times set by these bits. If the ADP1051 fails to
restart (the fault condition is no longer present and the ADP1051 is delivering power to the output
and operating as programmed) in the allowed number of retries, it disables the output and remains off
until the fault is cleared. The time between the start of each attempt to restart is set by the Delay
Time 2 value in Bits[2:0], together with the delay time unit specified for that particular fault.
111 = attempts to restart continuously, without limitation, until it is commanded off (by the CTRL
pin or the OPERATION command, or both), bias power is removed, or another fault condition causes
the unit to shut down.
[2:0] Delay time R/W These bits set the delay time.
Bit 2 Bit 1 Bit 0 Delay Time 1 (ms) Delay Time 2 (ms)
0 0 0 0 252
0 0 1 20 588
0
1
0
40
924
0 1 1 80 1260
1 0 0 160 1596
1 0 1 320 1932
1 1 0 640 2268
1 1 1 1280 2604
IOUT_OC_LV_FAULT_LIMIT
The IOUT_OC_LV_FAULT_LIMIT command sets the voltage threshold in cases for which the response to an overcurrent condition is to
operate in a constant current mode unless the output voltage is pulled below the specified limit value.
Table 44. Register 0x48—IOUT_OC_LV_FAULT_LIMIT
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W 16-bit unsigned integer Y value for linear format X = Y × 2N.
N is defined in the VOUT_MODE command.
Rev. A | Page 67 of 108
ADP1051 Data Sheet
OT_FAULT_LIMIT
The OT_FAULT_LIMIT command sets the threshold value (in °C) for overtemperature protection. The range is 0°C to 156°C. If the
setting value is out of range, the limit is 156 and the return value is 156.
Table 45. Register 0x4F—OT_FAULT_LIMIT
Bits Bit Name/Function R/W Description
[15:11]
Exponent
R
5-bit twos complement N value for linear format X = Y × 2
N
. N is fixed at 0.
[10:8] Mantissa high bits R Mantissa high bits Y[10:8] value fixed at 0.
[7:0] Mantissa low bits R/W Mantissa low bits Y[7:0] value for linear format X = Y × 2N.
OT_FAULT_RESPONSE
Table 46. Register 0x50—OT_FAULT_RESPONSE
Bits Bit Name/Function R/W Description
[7:6] Response R/W 00 = continues operation without interruption.
01 = continues operation for the Delay Time 1 specified by Bits[2:0] and the delay time unit
specified for that particular fault. If the fault condition is still present at the end of the delay time, the
unit responds as programmed in the retry setting (Bits[5:3]).
10 = shuts down (disables the output) and responds according to the retry setting in Bits[5:3].
11 = the output is disabled while the fault is present. Operation resumes and the output is enabled
when the fault condition no longer exists.
[5:3] Retry setting R/W 000 = restart not attempted. The output remains disabled until the fault is cleared.
001 to 110 = attempts to restart the number of times set by these bits. If the device fails to restart
in the allowed number of retries, it disables the output and remains off until the fault is cleared.
The time between the start of each attempt to restart is set by the Delay Time 2 value in Bits[2:0],
together with the delay time unit specified for that particular fault.
111 = attempts to restart continuously, without limitation, until commanded off (by the CTRL pin or
the OPERATION command, or both), VDD is removed, or another fault condition causes the unit to
shut down.
[2:0] Delay time R/W These bits set the delay time.
Bit 2 Bit 1 Bit 0 Delay Time 1 (sec) Delay Time 2 (ms)
0 0 0 1 252
0 0 1 1 588
0 1 0 1 924
0 1 1 1 1260
1 0 0 1 1596
1
0
1
1
1932
1 1 0 1 2268
1 1 1 1 2604
Rev. A | Page 68 of 108
Data Sheet ADP1051
Rev. A | Page 69 of 108
POWER_GOOD_ON
The POWER_GOOD_ON command sets the output voltage (in volts) at which the POWER_GOOD signal is asserted. The POWER_GOOD
status bit (POWER_GOOD) in the STATUS_WORD command is always reflective of VOUT with regard to the POWER_GOOD_ON and
POWER_GOOD_OFF limits.
Table 47. Register 0x5E—POWER_GOOD_ON
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the output voltage for the POWER_GOOD_ON command.
16-bit unsigned integer Y value for linear format X = Y × 2N.
N is defined by the VOUT_MODE command.
POWER_GOOD_OFF
The POWER_GOOD_OFF command sets the output voltage (in volts) at which the POWER_GOOD signal is negated. The POWER_GOOD
status bit (POWER_GOOD) in the STATUS_WORD command is always reflective of VOUT with regard to the POWER_GOOD_ON and
POWER_GOOD_OFF limits.
Table 48. Register 0x5F—POWER_GOOD_OFF
Bits Bit Name/Function R/W Description
[15:0] Mantissa R/W Sets the output voltage for the POWER_GOOD_OFF command.
16-bit unsigned integer Y value for linear format X = Y × 2N.
N is defined by the VOUT_MODE command.
TON_DELAY
The TON_DELAY command sets the turn-on delay time in milliseconds (ms). Only the following options are supported in the ADP1051.
Table 49. Register 0x60—TON_DELAY (Turn-On Delay Options Supported in the ADP1051)
Register Setting Turn-On Delay Time (ms)
0000000000000000 (0x0000) 0
0000000000001010 (0x000A) 10
0000000000011001 (0x0019) 25
0000000000110010 (0x0032) 50
0000000001001011 (0x004B) 75
0000000001100100 (0x0064) 100
0000000011111010 (0x00FA) 250
0000001111101000 (0x03E8) 1000
Table 50. Register 0x60—TON_DELAY
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
TON_RISE
The TON_RISE command sets the turn-on rise time in ms. Only the following values are supported in the ADP1051.
Table 51. Register 0x61—TON_RISE (Turn-On Rise Time Options Supported in the ADP1051)
Register Setting Turn-On Rise Time (ms)
1100000000001101 (0xC00D) 0.05
1101000000001101 (0xD00D) 0.2
1111000000000111 (0xF007) 1.75
1111100000010101 (0xF815) 10.5
0000000000010101 (0x0015) 21
1111000010100001 (0xF0A1) 40.25
0000000000111100 (0x003C) 60
0000000001100100 (0x0064) 100
Table 52. Register 0x61—TON_RISE
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
ADP1051 Data Sheet
TOFF_DELAY
The TOFF_DELAY command sets the turn-off delay time in milliseconds (ms). Only the values listed in Table 53 are supported in the
ADP1051.
Table 53. Register 0x64—TOFF_DELAY (Turn-Off Delay Options Supported in the ADP1051)
Register Setting Turn-Off Delay Time (ms)
0000000000000000 (0x0000)
0
0000000000110010 (0x0032) 50
0000000011111010 (0x00FA) 250
0000001111101000 (0x03E8) 1000
Table 54. Register 0x64—TOFF_DELAY
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
STATUS_BYTE
Table 55. Register 0x78—STATUS_BYTE
Bits Bit Name/Function R/W Description
7 Reserved R Reserved.
6 POWER_OFF R This bit is asserted if the unit is not providing power to the output, regardless of the reason,
including simply not being enabled.
5 VOUT_OV_FAULT R An output overvoltage fault has occurred.
4 IOUT_OC_FAULT R An output overcurrent fault has occurred.
3 VIN_UV_FAULT R An input undervoltage fault has occurred.
2 TEMPERATURE R A temperature fault or warning has occurred.
1 CML R A communications, memory, or logic fault has occurred.
0 NONE OF THE ABOVE R A fault or warning not listed in Bits[7:1] has occurred.
STATUS_WORD
Table 56. Register 0x79—STATUS_WORD
Bits Bit Name/Function R/W Description
15 VOUT R Any bit asserted in STATUS_VOUT asserts this bit.
14
IOUT
R
Any bit asserted in STATUS_IOUT asserts this bit.
13 INPUT R Any bit asserted in STATUS_INPUT asserts this bit.
12 Reserved R Reserved.
11
POWER_GOOD
R
POWER_GOOD is a negation of POWER_GOOD, which means that the output power is not good.
This bit is set when the sensed VOUT is less than the limit programmed in the POWER_GOOD_OFF
command. This bit is cleared when the sensed VOUT voltage is greater than the limit that is programmed
in the POWER_GOOD_ON command. This flag also triggers the PGOOD flag in Register 0xFEA0[6].
[10:7] Reserved R Reserved.
6
POWER_OFF
R
This bit is asserted if the unit is not providing power to the output, regardless of the reason,
including not being enabled.
5 VOUT_OV_FAULT R An output overvoltage fault has occurred.
4 IOUT_OC_FAULT R An output overcurrent fault has occurred.
3 VIN_UV_FAULT R An input undervoltage fault has occurred.
2 TEMPERATURE R An overtemperature fault or warning has occurred.
1 CML R A communications, memory, or logic fault has occurred.
0 NONE OF THE ABOVE R A fault or warning not listed in Bits[7:1] has occurred.
Rev. A | Page 70 of 108
Data Sheet ADP1051
STATUS_VOUT
Table 57. Register 0x7A—STATUS_VOUT
Bits Bit Name/Function R/W Description
7 VOUT_OV_FAULT R An output overvoltage fault has occurred.
[6:5] Reserved R Reserved.
4 VOUT_UV_FAULT R An output undervoltage fault has occurred.
3 VOUT_MAX warning An attempt was made to set the output voltage to a value greater than allowed by the VOUT_MAX
command.
[2:0] Reserved R Reserved.
STATUS_IOUT
Table 58. Register 0x7B—STATUS_IOUT
Bits Bit Name/Function R/W Description
7 IOUT_OC_FAULT R An output overcurrent fault has occurred.
[6:0] Reserved R Reserved.
STATUS_INPUT
Table 59. Register 0x7C—STATUS_INPUT
Bits Bit Name/Function R/W Description
[7:5] Reserved R Reserved.
4
VIN_UV_FAULT
R
An input undervoltage fault has occurred.
3 VIN_LOW R The unit is off due to insufficient input voltage.
2 IIN_OC_FAST_FAULT R An input overcurrent fast fault has occurred.
[1:0] Reserved R Reserved.
STATUS_TEMPERATURE
Table 60. Register 0x7D—STATUS_TEMPERATURE
Bits Bit Name/Function R/W Description
7 OT_FAULT R An overtemperature fault has occurred.
6 OT_WARNING R An overtemperature warning has occurred.
[5:0] Reserved R Reserved.
STATUS_CML
Table 61. Register 0x7E—STATUS_CML
Bits Bit Name/Function R/W Description
7 CMD_ERR R An invalid or unsupported command is received.
6
DATA_ERR
R
Invalid or unsupported data is received.
[5:2] Reserved R Reserved.
1 COMM_ERR R Other communication fault is detected.
0
Reserved
R
Reserved.
READ_VIN
The READ_VIN command returns the input voltage value (V) in linear format.
Table 62. Register 0x88—READ_VIN
Bits Bit Name/Function R/W Description
[15:11] Exponent R 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R 11-bit twos complement Y value for linear format X = Y × 2N.
READ_IIN
The READ_IIN command returns the input current value (A) in linear format.
Table 63. Register 0x89—READ_IIN
Bits Bit Name/Function R/W Description
[15:11]
Exponent
R
5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R 11-bit twos complement Y value for linear format X = Y × 2N.
Rev. A | Page 71 of 108
ADP1051 Data Sheet
READ_VOUT
The READ_VOUT command returns the output voltage value (V) in linear format.
Table 64. Register 0x8B—READ_VOUT
Bits Bit Name/Function R/W Description
[15:0] Mantissa R 16-bit unsigned integer Y value for linear format X = Y × 2N.
N is defined in the VOUT_MODE command.
READ_IOUT
The READ_IOUT command returns the output current value (A) in linear format.
Table 65. Register 0x8C—READ_IOUT
Bits Bit Name/Function R/W Description
[15:11] Exponent R 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R 11-bit twos complement Y value for linear format X = Y × 2N.
READ_TEMPERATURE
The READ_TEMPERATURE command returns the temperature value (in °C) in linear format.
Table 66. Register 0x8D—READ_TEMPERATURE
Bits Bit Name/Function R/W Description
[15:11]
Exponent
R
5-bit N value for linear format X = Y × 2
N
.
5-bit twos complement fixed at 00000.
[10:0] Mantissa R 11-bit twos complement Y value for linear format X = Y × 2N.
READ_DUTY_CYCLE
The READ_DUTY_CYCLE command returns the duty cycle of the PWM output value in linear format.
Table 67. Register 0x94—READ_DUTY_CYCLE
Bits Bit Name/Function R/W Description
[15:11] Exponent R 5-bit N value for linear format X = Y × 2N.
5-bit twos complement fixed at 10110 (−10 decimal).
[10:0] Mantissa R 11-bit twos complement Y value for linear format X = Y × 2N.
READ_FREQUENCY
The READ_FREQUENCY command returns the switching frequency value in linear format.
Table 68. Register 0x95—READ_FREQUENCY
Bits Bit Name/Function R/W Description
[15:11] Exponent R 5-bit twos complement N value for linear format X = Y × 2N.
[10:0] Mantissa R 11-bit twos complement Y value for linear format X = Y × 2N.
READ_PMBUS_REVISION
The READ_PMBUS_REVISION command returns the PMBus version information. The ADP1051 supports PMBus Revision 1.2.
Reading of this command results in a value of 0x22.
Table 69. Register 0x98—READ_PMBUS_REVISION
Bits Bit Name/Function R/W Description
[7:4] Part1 revision R Compliant to PMBus specifications, part 1: 0010 = Revision 1.2.
[3:0] Part2 revision R Compliant to PMBus specifications, part 2: 0010 = Revision 1.2.
Rev. A | Page 72 of 108
Data Sheet ADP1051
MFR_ID
Table 70. Register 0x99—MFR_ID
Bits Bit Name/Function R/W Description
[7:0] MFR_ID R/W Reads/writes the ID information of the manufacturer, which can be saved in the EEPROM.
MFR_MODEL
Table 71. Register 0x9A—MFR_MODEL
Bit Bit Name/Function R/W Description
[7:0] MFR_MODEL R/W Reads/writes the model information of the manufacturer, which can be saved in the EEPROM.
MFR_REVISION
Table 72. Register 0x9B—MFR_REVISION
Bit
Bit Name/Function
R/W
Description
[7:0] MFR_REVISION R/W Reads/writes the revision information of the manufacturer, which can be saved in the EEPROM.
IC_DEVICE_ID
Table 73. Register 0xAD—IC_DEVICE_ID
Bit Bit Name/Function R/W Description
[15:0] IC_DEVICE_ID R Reads the IC device ID (default value = 0x4151).
IC_DEVICE_REV
Table 74. Register 0xAE—IC_DEVICE_REV
Bits
Bit Name/Function
R/W
Description
[7:0] IC_DEVICE_REV R Reads the IC revision information. The value is 0x20 in the current silicon.
EEPROM_DATA_00
Table 75. Register 0xB0—EEPROM_DATA_00
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_00 R block Block read data from Page 0 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_01
Table 76. Register 0xB1—EEPROM_DATA_01
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_01 R block Block read data from Page 1 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_02
Table 77. Register 0xB2—EEPROM_DATA_02
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_02 R/W block Block read/write data of Page 2 of the EEPROM main block. The EEPROM must first be
unlocked. This page is not recommended for other use.
EEPROM_DATA_03
Table 78. Register 0xB3—EEPROM_DATA_03
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_03 R/W block Block read/write data of Page 3 of the EEPROM main block. The EEPROM must first be
unlocked. This page is reserved for storing power board parameter data for GUI use.
EEPROM_DATA_04
Table 79. Register 0xB4—EEPROM_DATA_04
Bits
Bit Name/Function
R/W
Description
[7:0] EEPROM_DATA_04 R/W block Block read/write data of Page 4 of the EEPROM main block. The EEPROM must first be unlocked.
Rev. A | Page 73 of 108
ADP1051 Data Sheet
EEPROM_DATA_05
Table 80. Register 0xB5—EEPROM_DATA_05
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_05 R/W block Block read/write data of Page 5 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_06
Table 81. Register 0xB6—EEPROM_DATA_06
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_06 R/W block Block read/write data of Page 6 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_07
Table 82. Register 0xB7—EEPROM_DATA_07
Bits
Bit Name/Function
R/W
Description
[7:0] EEPROM_DATA_07 R/W block Block read/write data of Page 7 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_08
Table 83. Register 0xB8—EEPROM_DATA_08
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_08 R/W block Block read/write data of Page 8 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_09
Table 84. Register 0xB9—EEPROM_DATA_09
Bits
Bit Name/Function
R/W
Description
[7:0] EEPROM_DATA_09 R/W block Block read/write data of Page 9 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_10
Table 85. Register 0xBA—EEPROM_DATA_10
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_10 R/W block Block read/write data of Page 10 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_11
Table 86. Register 0xBB—EEPROM_DATA_11
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_11 R/W block Block read/write data of Page 11 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_12
Table 87. Register 0xBC—EEPROM_DATA_12
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_12 R/W block Block read/write data of Page 12 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_13
Table 88. Register 0xBD—EEPROM_DATA_13
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_13 R/W block Block read/write data of Page 13 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_14
Table 89. Register 0xBE—EEPROM_DATA_14
Bits Bit Name/Function R/W Description
[7:0] EEPROM_DATA_14 R/W block Block read/write data of Page 14 of the EEPROM main block. The EEPROM must first be unlocked.
EEPROM_DATA_15
Table 90. Register 0xBF—EEPROM_DATA_15
Bits Bit Name/Function R/W Description
[7:0]
EEPROM_DATA_15
R/W block
Block read/write data of Page 15 of the EEPROM main block. The EEPROM must first be unlocked.
Rev. A | Page 74 of 108
Data Sheet ADP1051
Rev. A | Page 75 of 108
EEPROM_CRC_CHKSUM
Table 91. Register 0xD1—EEPROM_CRC_CHKSUM
Bits Bit Name/Function R/W Description
[7:0] CRC checksum R Returns the CRC checksum value from the EEPROM download operation.
EEPROM_NUM_RD_BYTES
Table 92. Register 0xD2—EEPROM_NUM_RD_BYTES
Bits Bit Name/Function R/W Description
[7:0] Number of read bytes
returned
R/W These bits set the number of read bytes that are returned when the EEPROM_DATA_xx
commands are used.
EEPROM_ADDR_OFFSET
Table 93. Register 0xD3—EEPROM_ADDR_OFFSET
Bits Bit Name/Function R/W Description
[15:0] Address offset R/W These bits set the address offset of the current EEPROM page.
EEPROM_PAGE_ERASE
Table 94. Register 0xD4—EEPROM_PAGE_ERASE
Bits Bit Name/Function R/W Description
[7:0] EEPROM page erase W Perform a page erase on the selected EEPROM page (Page 3 to Page 15). Wait 35 ms after each
page erase operation. The EEPROM must first be unlocked.
Page 0 and Page 1 are reserved for storing the default settings and user settings, respectively. The
user cannot perform a page erase of Page 0 or Page 1.
Page 2 is reserved for internal use; do not erase the contents of Page 2.
Page 3 is reserved for storing the board parameters for GUI use; erase Page 3 before storing the
board parameters.
The following list shows the register setting used to access each page:
0x03 = Page 3.
0x04 = Page 4.
0x05 = Page 5.
0x06 = Page 6.
0x07 = Page 7.
0x08 = Page 8.
0x09 = Page 9.
0x0A = Page 10.
0x0B = Page 11.
0x0C = Page 12.
0x0D = Page 13.
0x0E = Page 14.
0x0F = Page 15.
EEPROM_PASSWORD
Table 95. Register 0xD5—EEPROM_PASSWORD
Bits Bit Name/Function R/W Description
[7:0] EEPROM password W Writes the password using this command to unlock the EEPROM for read/write access. Writes the
EEPROM password two consecutive times to unlock the EEPROM. Writes any other value to exit.
The factory default password is 0xFF.
TRIM_PASSWORD
Table 96. Register 0xD6—TRIM_PASSWORD
Bits Bit Name/Function R/W Description
[7:0] Trim password W Writes the password using this command to unlock the trim registers for write access. Writes the
trim password two consecutive times to unlock the registers. Writes any other value to exit. The trim
password is the same as the EEPROM password. The factory default password is 0xFF.
ADP1051 Data Sheet
CHIP_PASSWORD
Table 97. Register 0xD7—CHIP_PASSWORD
Bits Bit Name/Function R/W Description
[15:0] Chip password W Writes the correct chip password two consecutive times to unlock the chip registers for
read/write access. Writes any other value to exit. The factory default password is 0xFFFF. This
register cannot be read. Any read action on this register returns 0.
VIN_SCALE_MONITOR
The VIN_SCALE_MONITOR command is the scale factor between the VIN ADC value and the real input voltage. It is typically used with
the READ_VIN command. The value must be in the range of 0 to 1 decimal.
Table 98. Register 0xD8—VIN_SCALE_MONITOR
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear format X = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear format X = Y × 2N.
IIN_SCALE_MONITOR
The IIN_SCALE_MONITOR command is the scale factor between the IIN ADC value and the real input current. It is typically used with
the READ_IIN command. The value must be in the range of 0 to 1 decimal.
Table 99. Register 0xD9—IIN_SCALE_MONITOR
Bits Bit Name/Function R/W Description
[15:11] Exponent R/W 5-bit twos complement N value for linear mode format X = Y × 2N.
N should be in the range of −12 to 0 decimal.
[10:0] Mantissa R/W 11-bit twos complement Y value for linear mode format X = Y × 2N.
EEPROM_INFO
Register 0xF1 is a read/write block. The EEPROM_INFO command reads the first flag data from the EEPROM.
Table 100. Register 0xF1—EEPROM_INFO
Bits Bit Name/Function R/W Description
[7:0]
EEPROM_INFO
R block
Block read data of the EEPROM information block.
MFR_SPECIFIC_1
Table 101. Register 0xFA—MFR_SPECIFIC_1
Bits Bit Name/Function R/W Description
[7:0] Customized register R/W These bits are available to the user to store customized information.
This register also stores the CS2 high-side mode factory analog trim value. Copy this value to
Register 0xFE17 to restore the CS2 high-side mode factory trim value.
MFR_SPECIFIC_2
Table 102. Register 0xFB—MFR_SPECIFIC_2
Bits Bit Name/Function R/W Description
[7:0] Customized register R/W These bits are available to the user to store customized information.
This register also stores the CS2 high-side mode factory digital offset trim value. Copy this value
to Register 0xFE16 to restore the CS2 high-side mode factory trim value.
Rev. A | Page 76 of 108
Data Sheet ADP1051
MANUFACTURER SPECIFIC EXTENDED COMMANDS DESCRIPTIONS
FLAG CONFIGURATION REGISTERS
Register 0xFE00 to Register 0xFE03 are used to set the fault flag response and the resolution after the flag is cleared. Register 0xFE05[5:4]
sets the VDD_OV flag response. Register 0xFE05[7:6] sets the global flag reenable delay time.
Table 103. Register 0xFE00 to Register 0xFE05—Flag Response Registers
Register Bits Flag Additional Settings
0xFE00 [7:4] Reserved Reserved
0xFE00 [3:0] IIN_OC_FAST_FAULT_RESPONSE Register 0xFE08, Register 0xFE0E, Register 0xFE1A, Register 0xFE1F,
Register 0xFEA0, Register 0xFEA3
0xFE01 [7:4] Extended VOUT_OV_FAULT_RESPONSE Register 0x40, Register 0x41, Register 0xFE26, Register 0xFE6B, Register 0xFE6C
0xFE01 [3:0] CS3_OC_FAULT_RESPONSE Register 0xFE6A, Register 0xFEA0, Register 0xFEA3
0xFE02 [7:4] VIN_UV_FAULT_RESPONSE Register 0x35, Register 0x36, Register 0xFE29, Register 0xFEA1, Register 0xFEA4
0xFE02 [3:0] Reserved Reserved
0xFE03 [7:4] SR_RC_FAULT_RESPONSE Register 0xFE1A, Register 0xFEA1, Register 0xFEA4
0xFE03 [3:0] FLAGIN_RESPONSE Register 0xFE12, Register 0xFEA1, Register 0xFEA4
0xFE05 [5:4] VDD_OV_RESPONSE Register 0xFE05, Register 0xFEA0, Register 0xFEA3
0xFE05 [3:0] Reserved Reserved
Table 104. Register 0xFE00 to Register 0xFE02—Flag Response Register Bit Descriptions
Bits Bit Name/Function R/W Description
[7:6] Fault response R/W These bits specify the action when the flag is set.
Bit 7 Bit 6 Flag Action
0 0 Continues operation without interruption.
0 1 Disables SR1 and SR2.
1 0 Disables all PWM outputs.
1 1 Reserved.
[5:4] Action after flag
is cleared
R/W These bits specify the action when the flag is cleared.
Bit 5 Bit 4 Action After Flag Clearing
0 0 After the reenable delay time, the PWM outputs are reenabled with a soft start.
0 1 The PWM outputs are reenabled immediately without a soft start.
1 0 A PSON signal, through Register 0x01, Register 0x02, and/or the CTRL pin,
is needed to reenable the PWM outputs.
1 1 Reserved.
[3:2] Fault response R/W These bits specify the action when the flag is set.
Bit 3 Bit 2 Flag Action
0 0 Continues operation without interruption.
0 1 Disables SR1 and SR2.
1 0 Disables all PWM outputs.
1 1 Reserved.
[1:0] Action after flag
is cleared
R/W These bits specify the action when the flag is cleared.
Bit 1 Bit 0 Action After Flag Clearing
0 0 After the reenable delay time, the PWM outputs are reenabled with a soft start.
0 1 The PWM outputs are reenabled immediately without a soft start.
1 0 A PSON signal, through Register 0x01, Register 0x02, and/or the CTRL pin, is
needed to reenable the PWM outputs.
1 1 Reserved.
Rev. A | Page 77 of 108
ADP1051 Data Sheet
Table 105. Register 0xFE03—Flag Response Register Bit Descriptions
Bits Bit Name/Function R/W Description
[7:6] Fault response R/W These bits specify the action when the flag is set.
Bit 7 Bit 6 Fault Response
0 0 Continues operation without interruption.
0 1 Disables SR1 and SR2.
1 0 Disables all PWM outputs.
1 1 The rising edges of SR1 and SR2 move to tRx + tMODU_LIMIT − tOFFSET.
See the SR Reverse Current Protection section for more information.
[5:4] Action after the fault
flag is cleared
R/W These bits specify the action when the flag is cleared.
Bit 5 Bit 4 Bits[7:6] = 01 or 10 Bits [7:6] = 11
0 0 After the flag reenable delay time, the PWM
outputs are reenabled with a soft start.
SR1 and SR2 follow the soft recovery
process.
0 1 The PWM outputs are reenabled
immediately without a soft start.
SR1 and SR2 immediately recover to
normal condition.
1 0 A PSON signal is needed to reenable the
PWM outputs.
Reserved.
1 1 Reserved. Reserved.
[3:2]
Fault response
R/W
These bits specify the action when the flag is set.
Bit 3 Bit 2 Fault Response
0 0 Continues operation without interruption.
0 1 Disable SR1 and SR2.
1 0 Disable all PWM outputs.
1 1 Reserved.
[1:0] Action after the fault
flag is cleared
R/W These bits specify the action when the flag is cleared.
Bit 1 Bit 0 Action After Fault Flag Clears
0 0 After the flag reenable delay time, the PWM outputs are reenabled with a soft start.
0 1 The PWM outputs are reenabled immediately without a soft start.
1
0
A PSON signal, programmed in Register 0x01, Register 0x02, and/or the CTRL pin, is
needed to reenable the PWM outputs.
1 1 Reserved.
Table 106. Register 0xFE05—Flag Reenable Delay, VDD_OV_RESPONSE
Bits Bit Name/Function R/W Description
[7:6]
Flag reenable delay
R/W
These bits specify the global delay from the time when a manufacturer specific flag is cleared to the
soft start.
Bit 7 Bit 6 Typical Delay Time (sec)
0 0 250 m
0 1 500 m
1 0 1
1 1 2
5 VDD_OV flag ignore R/W This bit enables or disables the VDD_OV flag.
0 = VDD_OV flag is set when there is a VDD overvoltage condition. When there is a VDD overvoltage
condition, the flag is set and the part shuts down. When the VDD overvoltage condition ends, the flag
is cleared and the part downloads the EEPROM contents before restarting with a soft start process.
1 = VDD_OV flag is always cleared. When there is a VDD overvoltage condition, the flag is always
cleared and the part continues to operate without interruption.
4 VDD_OV flag
debounce
R/W This bit sets the debounce time for the VDD_OV flag.
0 = 500 μs debounce time.
1 = 2 μs debounce time.
[3:0] Reserved R/W Reserved.
Rev. A | Page 78 of 108
Data Sheet ADP1051
SOFT START AND SOFTWARE RESET REGISTERS
Table 107. Register 0xFE06—Software Reset GO Command
Bits Bit Name/Function R/W Description
[7:1]
Reserved
R/W
Reserved.
0 Software reset GO W This bit allows the user to perform a software reset of the ADP1051. Setting this bit resets the part
with a restart delay period from the time the ADP1051 is turned off to the time ADP1051 restarts.
The restart delay is set using Register 0xFE07[1:0] .
Table 108. Register 0xFE07—Software Reset Settings
Bits Bit Name/Function R/W Description
[7:3] Reserved R/W Reserved.
2
Additional flag reenable
delay
R/W
This bit specifies whether an additional TON_DELAY value is added to the reenable delay after a
manufacturer specific flag is cleared and before the ADP1051 begins a soft start.
0 = no additional delay is added to the reenable delay.
1 = additional delay is added to the reenable delay. The delay time is specified in the TON_DELAY
command (Register 0x60).
[1:0] Restart delay R/W These bits specify the delay from the time when a PSON signal is set to the time when the soft
start begins.
Bit 1 Bit 0 Restart Delay (sec)
0 0 0 m
0 1 500 m
1 0 1
1 1 2
Table 109. Register 0xFE08—Synchronous Rectifier (SR) Soft Start Settings
Bits Bit Name/Function R/W Description
7 Reserved R/W Reserved.
6 CS1 cycle-by-cycle current
limit to disable SR2
R/W Setting this bit enables the CS1 cycle-by-cycle current limit to disable the SR2 output for the
remainder of the switching cycle when cycle-by-cycle current limiting occurs.
5 CS1 cycle-by-cycle current
limit to disable SR1
R/W Setting this bit enables the CS1 cycle-by-cycle current limit to disable the SR1 output for the
remainder of the switching cycle when cycle-by-cycle current limiting occurs.
4 SR soft start setting R/W 0 = the synchronous rectifiers perform a soft start only the first time that they are enabled.
1 = the synchronous rectifiers perform a soft start every time that they are enabled.
[3:2]
SR soft start speed
R/W
When an SR PWM output is configured to turn on with soft start (using Bits [1:0]), the rising edge
of the output moves to the left in steps of 40 ns. These bits specify the number of switching
cycles that are required to move the SR PWM output in a step of 40 ns.
Bit 3 Bit 2 SR Soft Start Timing
0 0 The SR PWM outputs change 40 ns in one switching cycle.
0 1 The SR PWM outputs change 40 ns in four switching cycles.
1 0 The SR PWM outputs change 40 ns in 16 switching cycles.
1 1 The SR PWM outputs change 40 ns in 64 switching cycles.
1 SR2 soft start R/W Setting this bit enables soft start for SR2.
0 SR1 soft start R/W Setting this bit enables soft start for SR1.
Rev. A | Page 79 of 108
ADP1051 Data Sheet
Table 110. Register 0xFE09—Soft Start Setting of Open-Loop Operation
Bits Bit Name/Function R/W Description
7 Open-loop operation
soft start enable
R/W Setting this bit enables the soft start of open-loop operation.
6 OUTA, OUTB, OUTC, and
OUTD edges
R/W When this bit is set, the falling edges of OUTA, OUTB, OUTC, and OUTD are always after the
rising edges in one cycle during the soft start of open-loop operation.
5 SR1 and SR2 edges R/W This bit is valid only when Bit 7 of this register is set to 1.
0 = the rising edges of SR1 and SR2 always occur after the falling edges in one cycle during
a soft start.
1 = the falling edges of SR1 and SR2 always occur after the rising edges in one cycle during
a soft start.
[4:3] Soft start speed of open-loop
operation and open-loop
feedforward operation
R/W When the ADP1051 is configured for open-loop operation, the falling edge of the PWM
output moves to the right in steps of 40 ns. When the ADP1051 is configured for open-
loop feedforward operation, the modulation edge of the PWM output moves from the
original position in steps of 40 ns. These bits specify how many switching cycles are
required to move the PWM outputs in 40 ns.
Bit 4 Bit 3 Open-Loop Soft Start Timing
0 0 The PWM outputs change 40 ns in one switching cycle
0 1 The PWM outputs change 40 ns in four switching cycles
1
0
The PWM outputs change 40 ns in 16 switching cycles
1 1 The PWM outputs change 40 ns in 64 switching cycles
2 Soft start variation for
open-loop operation
R/W Setting this bit enables global variation during the soft start of open-loop operation.
1 = all outputs use the time variation calculated by OUTB (tF2 − tR2).
[1:0] Reserved R/W Reserved.
BLANKING AND PGOOD SETTING REGISTERS
Table 111. Register 0xFE0B—Flag Blanking During Soft Start
Bits Bit Name/Function R/W Description
7
Blank SR_RC_FAULT flag
R/W
0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
6 Blank FLAGIN flag R/W 0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
5 Blank LIGHT_LOAD flag and
DEEP_LIGHT_LOAD flag
R/W 0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
4 Blank VIN_UV_FAULT flag R/W 0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
3 Blank IIN_OC_FAST_FAULT
flag
R/W 0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
2 Blank IOUT_OC_FAULT flag R/W 0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
1 Blank CS3_OC_FAULT flag R/W 0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
0
Blank VOUT_OV_FAULT flag
R/W
0 = blank this flag during soft start.
1 = do not blank this flag during soft start.
Rev. A | Page 80 of 108
Data Sheet ADP1051
Table 112. Register 0xFE0C—Volt-Second Balance Blanking and SR Disable During Soft Start
Bits Bit Name/Function R/W Description
[7:5] Reserved R/W Reserved.
4 VIN_UV_FAULT reenable blank R/W 0 = VIN_UV_FAULT flag is not blanked during the flag reenable delay. This is the recommended
setting if the input voltage signal can be sensed by the ADP1051 before the PSU starts to operate.
1 = VIN_UV_FAULT flag is blanked during the flag reenable delay.
3 First flag ID update R/W This bit specifies whether the first flag ID is saved in the EEPROM. If it is set, the first flag ID
is saved in the EEPROM. During the VDD power reset, the first flag ID is downloaded from the
EEPROM to Register 0xFEA6.
0 = the first flag ID is not saved in the EEPROM.
1 = the first flag ID is saved in the EEPROM.
2 Flag shutdown timing R/W Specifies when the PWM outputs are shut down after a manufacturer specific flag is triggered.
0 = the PWM outputs are shut down at the end of the switching cycle.
1 = the PWM outputs are shut down immediately.
1 Volt-second balance blanking R/W 0 = the volt-second balance control is not blanked during soft start.
1 = the volt-second balance control is blanked during soft start.
0 SR disable R/W 0 = SR1 and SR2 are not disabled during soft start.
1 = SR1 and SR2 are disabled during soft start.
Table 113. Register 0xFE0D—PGOOD Mask Settings
Bits Bit Name/Function R/W Description
7 VIN_UV_FAULT flag R/W 1 = the VIN_UV_FAULT flag is ignored by PGOOD.
6 IIN_OC_FAST_FAULT flag R/W 1 = the IIN_OC_FAST_FAULT flag is ignored by PGOOD.
5 IOUT_OC_FAULT flag R/W 1 = the IOUT_OC_FAULT flag is ignored by PGOOD.
4 VOUT_OV_FAULT flag R/W 1 = the VOUT_OV_FAULT flag is ignored by PGOOD.
3 VOUT_UV_FAULT flag R/W 1 = the VOUT_UV_FAULT flag is ignored by PGOOD.
2 OT_FAULT flag R/W 1 = the OT_FAULT flag is ignored by PGOOD.
1 OT_WARNING flag R/W 1 = the OT_WARNING flag is ignored by PGOOD.
0 SR_RC_FAULT flag R/W 1 = the SR_RC_FAULT flag is ignored by PGOOD.
Table 114. Register 0xFE0E—PGOOD Flag Debounce
Bits
Bit Name/Function
R/W
Description
7 CS1 cycle-by-cycle current limit to
disable OUTD
R/W Setting this bit enables the CS1 cycle-by-cycle current limit to disable the OUTD output for the
remainder of the switching cycle when cycle-by-cycle current limiting occurs.
6
CS1 cycle-by-cycle current limit to
disable OUTC
R/W
Setting this bit enables the CS1 cycle-by-cycle current limit to disable the OUTC output for the
remainder of the switching cycle when cycle-by-cycle current limiting occurs.
5 CS1 cycle-by-cycle current limit to
disable OUTB
R/W Setting this bit enables the CS1 cycle-by-cycle current limit to disable the OUTB output for the
remainder of the switching cycle when cycle-by-cycle current limiting occurs.
4 CS1 cycle-by-cycle current limit to
disable OUTA
R/W Setting this bit enables the CS1 cycle-by-cycle current limit to disable the OUTA output for the
remainder of the switching cycle when cycle-by-cycle current limiting occurs.
[3:2] PGOOD flag clearing debounce R/W These bits specify the PGOOD flag clearing debounce, which is the time from when the PGOOD
clearing condition is met to the time when the PGOOD flag is cleared.
Bit 3 Bit 2 PGOOD Flag Setting Debounce (ms)
0 0 0
0 1 200
1 0 320
1 1 600
[1:0] PGOOD flag setting debounce R/W These bits specify the PGOOD flag setting debounce, which is the time from when the PGOOD
setting condition is met to the time when the PGOOD flag is set.
Bit 1 Bit 0 PGOOD Flag Clearing Debounce (ms)
0 0 0
0 1 200
1 0 320
1 1 600
Rev. A | Page 81 of 108
ADP1051 Data Sheet
Table 115. Register 0xFE0F—Debounce Time for Asserting PGOOD
Bits Bit Name/Function R/W Debounce Time (ms)
7 VIN_UV_FAULT to assert PGOOD R/W 0 = 0
1 = 1.3
6 IIN_OC_FAST_FAULT to assert PGOOD R/W 0 = 0
1 = 1.3
5
IOUT_OC_FAULT to assert PGOOD
R/W
0 = 0
1 = 1.3
4
VOUT_OV_FAULT to assert PGOOD
R/W
0 = 0
1 = 1.3
3 VOUT_UV_FAULT to assert PGOOD R/W 0 = 0
1 = 1.3
2 OT_FAULT to assert PGOOD R/W 0 = 0
1 = 1.3
1 OT_WARNING to assert PGOOD R/W 0 = 0
1 = 1.3
0 SR_RC_FAULT to assert PGOOD R/W 0 = 0
1 = 1.3
SWITCHING FREQUENCY AND SYNCHRONIZATION REGISTERS
When synchronization is enabled, the ADP1051 takes the SYNI signal and adds the tSYNC_DELAY, together with a 760 ns propagation delay, to
generate the internal synchronization reference clock as shown in Figure 65. The ADP1051 uses the reference clock to generate its own clock.
760ns +
tSYNC_DELAY
t0tS
CLOCKSYNC
SYNI
11443-064
Figure 65. Synchronization Timing
Table 116. Register 0xFE11—Synchronization Delay Time
Bits Bit Name/Function R/W Description
[7:0] tSYNC_DELAY R/W Sets the additional delay of the synchronization reference clock to the rising edge of the SYNI pin
signal. Each LSB size is 40 ns.
Note that this delay time cannot exceed one switching period. If the PWM 180° phase shift is
enabled, this delay time cannot exceed one-half of one switching period.
Table 117. Register 0xFE12—Synchronization General Settings
Bits Bit Name/Function R/W Description
7 Reserved R/W Reserved.
6 Phase capture range
for synchronization
R/W Sets the phase capture range. The ADP1051 detects the phase shift between the external and internal
clocks when synchronization function is enabled. When the phase shift falls within the range,
synchronization starts.
0 = phase capture range is ±3.125% (±11.25°).
1 = phase capture range is ±6.25% (±22.5°). This is the recommended setting.
5 OUTD used as SYNO R/W 0 = OUTD is used as the PWM output.
1 = OUTD is used as SYNO output.
4 OUTC used as SYNO R/W 0 = OUTC is used as PWM output.
1 = OUTC is used as SYNO output.
3 Enable
synchronization
R/W Setting this bit enables frequency synchronization as a slave device. The ADP1051 synchronizes with
the external clock through the SYNI/FLGI pin. Bit 0 = 0 if synchronization is enabled.
2 FLGI polarity R/W Sets the polarity for the SYNI/FLGI pin when the pin is programmed as FLGI.
0 = a high logic level on the FLGI pin sets the FLAGIN flag; a low logic level clears the FLAGIN flag.
1 = a low logic level on the FLGI pin sets the FLAGIN flag; a high logic level sets the FLAGIN flag.
Rev. A | Page 82 of 108
Data Sheet ADP1051
Bits Bit Name/Function R/W Description
1 FLAGIN flag
debounce time
R/W 0 = 0 μs debounce time for the FLAGIN flag.
1 = 100 μs debounce time for the FLAGIN flag.
0 SYNI/FLGI
pin function
selection
R/W Configures the SYNI/FLGI pin as a flag input or a synchronization input. When SYNI is not enabled,
this bit must be set to 1.
0 = the SYNI/FLGI pin is used as the synchronization input (SYNI).
1 = the SYNI/FLGI pin is used as the flag input (FLGI).
Table 118. Register 0xFE13—Dual-Ended Topology Mode
Bits Bit Name/Function R/W Description
7 Reserved R/W Reserved.
6 Dual-ended
topology enable
R/W Setting this bit to 1 means that dual-ended topologies are used. It affects the modulation high limit.
The modulation limit in each half cycle is one-half of the modulation limit that is programmed in
Register 0xFE3C.
0 = operates in single-ended topologies, such as buck, forward, and flyback.
1 = operates in dual-ended topologies, such as full bridge, half bridge, and push pull.
[5:0] Reserved R/W Reserved.
CURRENT SENSE AND LIMIT SETTING REGISTERS
Table 119. Register 0xFE14—CS1 Gain Trim
Bits Bit Name/Function R/W Description
7 Gain polarity R/W Setting this bit to 1 means that negative gain is introduced.
0 = positive gain is introduced.
1 = negative gain is introduced.
[6:0] CS1 gain trim R/W This value calibrates the CS1 current sense gain. Apply 1 V dc at the CS1 pin. This register is
trimmed until the CS1 value reads 2560 decimal (0xA00).
Table 120. Register 0xFE15—CS2 Gain Trim
Bits Bit Name/Function R/W Description
7
Gain polarity
R/W
Setting this bit to 1 means that negative gain is introduced.
0 = positive gain is introduced.
1 = negative gain is introduced
[6:0]
CS2 gain trim
R/W
This value calibrates the CS2 current sense gain.
Table 121. Register 0xFE16—CS2 Digital Offset Trim
Bits Bit Name/Function R/W Description
[7:0] CS2 digital offset
trim
R/W This register contains CS2 digital offset trim value. The value is used to calibrate the CS2 value.
The default value is the factory trim value of CS2 low-side current mode. Copy the Register 0xFB value
to this register to restore the factory trim value of CS2 high-side current sense mode.
Table 122. Register 0xFE17—CS2 Analog Trim
Bits Bit Name/Function R/W Description
7 Reserved R/W Reserved.
6 Analog trim polarity R/W Setting this bit to 1 means that negative trim is introduced. Setting this bit to 0 means that positive
trim is introduced.
The default value is the factory trim value of CS2 low-side current sense mode. Copy the Register 0xFA[6]
value to this bit to restore the factory trim value of CS2 high-side current sense mode.
[5:0] CS2 analog trim R/W The value calibrates the CS2 analog trim.
The default value is the factory trim value of CS2 low-side current mode. Copy the Register 0xFA[5:0]
value to these bits to restore the factory trim value of CS2 high-side current mode.
Rev. A | Page 83 of 108
ADP1051 Data Sheet
Table 123. Register 0xFE19—CS2 Light Load Threshold
Bits Bit Name/Function R/W Description
7 CS2 current sense
mode
R/W 0 = CS2 current sense is configured as low-side current sense mode.
1 = CS2 current sense is configured as high-side current sense mode.
[6:5] CS3_OC_FAULT flag
debounce
R/W These two bits set the CS3_OC_FAULT flag debounce time.
Bit 6 Bit 5 Debounce Time (ms)
0 0 0
0 1 10
1 0 20
1 1 200
4 CS2 light load mode
enable
R/W Setting this bit enables the light load mode function. When the CS2 current falls below the CS2 light
load mode threshold, the ADP1051 operates in light load mode.
[3:0] CS2 light load
threshold
R/W These bits set the current limit on the CS2 ADC to enter the light load mode value. This value determines
the point at which the LIGHT_LOAD flag is set. The hysteresis and the averaging speed are
programmable in Register 0xFE1E[5:2].
Bit 3 Bit 2 Bit 1 Bit 0
Light Load Threshold (mV)
328 μs 164 μs 82 μs 41 μs
0 0 0 0 0 0 0 0
0 0 0 1 0.9375 1.8750 3.7500 7.5000
0 0 1 0 1.8750 3.7500 7.5000 15.000
0 0 1 1 2.8125 5.6250 11.250 22.500
0 1 0 0 3.7500 7.5000 15.000 30.000
0 1 0 1 4.6875 9.3750 18.750 37.500
0 1 1 0 5.6250 11.250 22.500 45.000
0 1 1 1 6.5625 13.125 26.250 52.500
1 0 0 0 7.5000 15.000 30.000 60.000
1 0 0 1 8.4375 16.875 33.750 67.500
1 0 1 0 9.3750 18.750 37.500 75.000
1 0 1 1 10.313 20.625 41.250 82.500
1 1 0 0 11.250 22.500 45.000 90.000
1 1 0 1 12.188 24.375 48.750 97.500
1 1 1 0 13.125 26.250 52.500 105.00
1 1 1 1 14.063 28.125 56.250 112.50
Table 124. Register 0xFE1A—IIN_OC_FAST_FAULT_LIMIT and SR_RC_FAULT_LIMIT
Bits Bit Name/Function R/W Description
7 Reserved R/W Reserved.
[6:4] IIN_OC_FAST_
FAULT_LIMIT
R/W If the CS1 cycle-by-cycle current-limit comparator is set and the CS1_OCP flag is triggered, all PWM
outputs that are on at that time can be programmed to be immediately disabled for the remainder of the
switching cycle. The PWM outputs resume normal operation at the beginning of the next switching cycle.
There is an internal counter, N, with an initial value of 0. N counts the CS1_OCP flag triggering number
in consecutive switching cycles. If the CS1_OCP flag is triggered in one cycle, then NCURRENT = NPREVIOUS + 2.
If the CS1_OCP flag is not triggered in one cycle and the previous N > 0, then NCURRENT = NPREVIOUS − 1.
If the CS1_OCP flag is not triggered and the previous N = 0, then NCURRENT = 0. When N reaches the
IIN_OC_FAST_FAULT_LIMIT value, the IIN_OC_FAST_FAULT flag is set.
Note that there is one cycle in single-ended topologies, such as buck converter and forward
converter. There are two cycles in double-ended topologies, such as full bridge converter, half bridge
converter, and push pull converter.
Bit 6 Bit 5 Bit 4 Limit Value
0 0 0 2
0 0 1 8
0
1
0
16
0
1
1
64
1
0
0
128
1
0
1
256
1
1
0
512
1
1
1
1024
Rev. A | Page 84 of 108
Data Sheet ADP1051
Bits Bit Name/Function R/W Description
3 SR_RC_FAULT flag
debounce time
R/W This bit sets the debounce time for the SR_RC_FAULT flag.
0 = 40 ns.
1 = 200 ns.
[2:0] SR_RC_FAULT_LIMIT R/W These bits program the reference voltage for CS2 reverse current comparator for generating the
SR_RC_FAULT flag. The difference in voltage between the CS2+ and CS2− pins is compared with this
limit. This comparator is an analog comparator.
Bit 2 Bit 1 Bit 0 Value (mV)
0 0 0 −3
0
0
1
−6
0
1
0
−9
0
1
1
−12
1
0
0
−15
1
0
1
−18
1
1
0
−21
1
1
1
−24
Table 125. Register 0xFE1B—CS2 Deep Light Load Mode Setting
Bits Bit Name/Function R/W Description
7 Reserved R/W Reserved.
6 CS1 cycle-by-cycle
current-limit ref
R/W 0 = the CS1 cycle-by-cycle current-limit reference is 1.2 V.
1 = the CS1 cycle-by-cycle current-limit reference is 0.25 V.
5 Reserved R/W Reserved.
4 CS2 averaging
speed for triggering
the IOUT_OC_FAULT
flag
R/W 0 = the 9-bit CS2 (output current) averaging speed is used for triggering the IOUT_OC_FAULT flag.
The basic VS voltage change rate for constant current control is 1.18 mV/ms.
1 = the 7-bit CS2 (output current) averaging speed is used for triggering the IOUT_OC_FAULT flag.
The basic VS voltage change rate for constant current control is 4.72 mV/ms.
[3:0] CS2 deep light load
mode threshold
R/W These bits set the current limit on the CS2 ADC to enter the deep light load mode value. This value
determines the point at which the DEEP_LIGHT_LOAD flag is set and some PWM outputs are disabled.
The averaging speed and the hysteresis are programmed in Register 0xFE1E.
Bit 3 Bit 2 Bit 1 Bit 0
Deep Light Load Threshold (mV)
328 μs 164 μs 82 μs 41 μs
0
0
0
0
0
0
0
0
0 0 0 1 0.9375 1.8750 3.7500 7.5000
0 0 1 0 1.8750 3.7500 7.5000 15.000
0 0 1 1 2.8125 5.6250 11.250 22.500
0 1 0 0 3.7500 7.5000 15.000 30.000
0 1 0 1 4.6875 9.3750 18.750 37.500
0 1 1 0 5.6250 11.250 22.500 45.000
0 1 1 1 6.5625 13.125 26.250 52.500
1 0 0 0 7.5000 15.000 30.000 60.000
1 0 0 1 8.4375 16.875 33.750 67.500
1 0 1 0 9.3750 18.750 37.500 75.000
1
0
1
1
10.313
20.625
41.250
82.500
1 1 0 0 11.250 22.500 45.000 90.000
1 1 0 1 12.188 24.375 48.750 97.500
1 1 1 0 13.125 26.250 52.500 105.00
1 1 1 1 14.063 28.125 56.250 112.50
Rev. A | Page 85 of 108
ADP1051 Data Sheet
Table 126. Register 0xFE1C—PWM Outputs Disable Settings at Deep Light Load Mode
Bits Bit Name/Function R/W Description
[7:6] Reserved R/W Reserved.
5
SR2 disable
R/W
Setting this bit disables the SR2 output when operating in deep light load mode.
4 SR1 disable R/W Setting this bit disables the SR1 output when operating in deep light load mode.
3 OUTD disable R/W Setting this bit disables the OUTD output when operating in deep light load mode.
2
OUTC disable
R/W
Setting this bit disables the OUTC output when operating in deep light load mode.
1 OUTB disable R/W Setting this bit disables the OUTB output when operating in deep light load mode.
0 OUTA disable R/W Setting this bit disables the OUTA output when operating in deep light load mode.
Table 127. Register 0xFE1D—Matched Cycle-by-Cycle Current-Limit Settings
Bits Bit Name/Function R/W Description
7 Reserved R/W Reserved.
6 Enable matched cycle-
by-cycle current limit
R/W Setting this bit enables the matched cycle-by-cycle current-limit function.
[5:4] Select PWM output
pairs for matched
cycle-by-cycle current
limit
R/W These bits select the PWM pairs for matched cycle-by-cycle current limiting.
Bit 5 Bit 4 PWM Pairs
0 0 OUTB and OUTD
0 1 OUTA and OUTC
1 0 OUTC and OUTD
1 1 OUTA and OUTB
3 OUTD rising edge
blanking
R/W This bit specifies whether the blanking time for the CS1 cycle-by-cycle current-limit comparator is
referenced to the rising edge of OUTD.
0 = no blanking at the OUTD rising edge.
1 = blanking time referenced to the OUTD rising edge.
2
OUTC rising edge
blanking
R/W
This bit specifies whether the blanking time for the CS1 cycle-by-cycle current-limit comparator is
referenced to the rising edge of OUTC.
0 = no blanking at the OUTC rising edge.
1 = blanking time referenced to the OUTC rising edge.
1 OUTB rising edge
blanking
R/W This bit specifies whether the blanking time for the CS1 cycle-by-cycle current-limit comparator is
referenced to the rising edge of OUTB.
0 = no blanking at the OUTB rising edge.
1 = blanking time referenced to the OUTB rising edge.
0 OUTA rising edge
blanking
R/W This bit specifies whether the blanking time for the CS1 cycle-by-cycle current-limit comparator is
referenced to the rising edge of OUTA.
0 = no blanking at the OUTA rising edge.
1 = blanking time referenced to the OUTA rising edge.
Table 128. Register 0xFE1E—Light Load Mode and Deep Light Load Mode Settings
Bits Bit Name/Function R/W Description
[7:6] CS2 averaging speed
for drooping control
R/W These bits set the CS2 (output current) averaging speed and resolution used for the drooping
control. Faster speed corresponds to lower resolution and, therefore, lowers accuracy of the
drooping line.
Bit 7 Bit 6 Speed (μs) Resolution (Bits)
0
0
82
7
0 1 164 8
1 0 328 9
1 1 656 10
[5:4] Light load mode and
deep light load mode
averaging speed
R/W These bits set the averaging speed and resolution used for the light load mode threshold and
deep light load mode threshold. Faster speed corresponds to lower resolution and, therefore,
to lower accuracy of the threshold.
Bit 5 Bit 4 Speed (μs) Resolution (Bits)
0 0 41 6
0 1 82 7
1 0 164 8
1 1 328 9
Rev. A | Page 86 of 108
Data Sheet ADP1051
Bits Bit Name/Function R/W Description
[3:2] Light load mode and
deep light load mode
hysteresis
R/W These bits set the amount of hysteresis applied to the light load mode and deep light load mode
thresholds. The size of the LSB is affected by different speed and resolution selected in Bits[5:4].
If the 120 mV ADC range is used with 8-bit resolution, the LSB size is 120 mV/28 = 469 μV.
Bit 3 Bit 2 Hysteresis (LSB)
0 0 3
0 1 8
1 0 12
1 1 16
1 SR2 response to cycle-
by-cycle limit
R/W This bit is applicable only when the SR2 output is programmed to be in complement with the OUTA
output. When this bit is set and there is a cycle-by-cycle current limit, the SR2 rising edge is turned on
when the cycle-by-cycle current limit disables the OUTA. Its falling edge still follows the
programmed value.
0 SR1 response to cycle-
by-cycle limit
R/W This bit is applicable only when the SR1 output is programmed to be in complement with the OUTB
output. When this bit is set, and there is a cycle-by-cycle current limit, the SR1 rising edge is turned on
when the cycle-by-cycle current limit disables the OUTB. Its falling edge still follows the
programmed value.
Table 129. Register 0xFE1F—CS1 Cycle-by-Cycle Current-Limit Settings
Bits Bit Name/Function R/W Description
7 CS1 cycle-by-cycle
current-limit
comparator ignored
R/W Setting this bit causes the CS1 OCP comparator output to be ignored. The CS1_OCP internal flag is
always cleared.
[6:4] Leading edge
blanking
R/W These bits determine the leading edge blanking time. During this time, the CS1 OCP comparator
output is ignored. This time is measured from the rising edges of OUTA, OUTB, OUTC, and OUTD
(programmable in Register 0xFE1D[3:0]).
Bit 6 Bit 5 Bit 4 Leading Edge Blanking Time (ns)
0
0
0
0
0 0 1 40
0 1 0 80
0 1 1 120
1 0 0 200
1
0
1
400
1 1 0 600
1 1 1 800
[3:2]
Reserved
R/W
Reserved.
[1:0] CS1 cycle-by-cycle
current-limit
debounce time
R/W These bits set the CS1 cycle-by-cycle current-limit debounce time. This is the minimum time that
the CS1 signal must be constantly above the CS1 cycle-by-cycle current-limit reference before the
PWM outputs are shut down. When this happens, the selected PWM outputs can be disabled for the
remainder of the switching cycle.
Bit 1 Bit 0 Debounce Time (ns)
0 0 0
0 1 40
1 0 80
1 1 120
Rev. A | Page 87 of 108
ADP1051 Data Sheet
VOLTAGE SENSE AND LIMIT SETTING REGISTERS
Table 130. Register 0xFE20—VS Gain Trim
Bits Bit Name/Function R/W Description
7
Trim polarity
R/W
0 = positive gain is introduced.
1 = negative gain is introduced.
[6:0] VS gain trim R/W These bits set the amount of gain trim that is applied to the VS ADC reading. This register trims the
voltage reading in the READ_VOUT command after the VOUT_CAL_OFFSET trimming is completed.
This register is trimmed until the READ_VOUT reading in the register exactly matches the output
voltage measurement result.
Table 131. Register 0xFE25—Pre-Bias Start-Up Enable
Bits Bit Name/Function R/W Description
7 Pre-bias startup
enable
R/W Setting this bit enables the pre-bias start-up function. If it is enabled, the soft start ramp starts from the
current output voltage. The initial PWM modulation value is generated based on the following: the
Register 0xFE39 setting, the sensed VOUT value, and the sensed VIN value. To introduce the VIN value for
initial modulation calculation, Register 0xFE6C[1] = 1, unless closed-loop input voltage feedforward
operation mode is in use.
[6:0] Reserved R/W Reserved.
Table 132. Register 0xFE26—VOUT_OV_FAULT Flag Debounce
Bits Bit Name/Function R/W Description
[7:6]
VOUT_OV_FAULT
flag debounce
R/W
These bits set the VOUT_OV_FAULT flag debounce time.
Bit 7 Bit 6 Typical Debounce Time (μs)
0 0 0
0 1 1
1 0 2
1 1 8
[5:0] Reserved R/W Reserved
Table 133. Register 0xFE28—VF Gain Trim
Bits Bit Name/Function R/W Description
7 Trim polarity R/W 0 = positive gain is introduced.
1 = negative gain is introduced.
[6:0] VF trim R/W These bits set the amount of gain trim that is applied to the VF ADC reading. This register trims the
voltage at the VF pin for external resistor tolerances. When there is 1 V on the VF pin, this register is
trimmed until the VF value register reads 1280 decimal (0x500).
Table 134. Register 0xFE29—VIN_ON and VIN_OFF Delay
Bits Bit Name/Function R/W Description
[7:6] Reserved R/W Reserved
5 VIN_UV_FAULT enable R/W Setting this bit enables the VIN_ON value and the VIN_OFF value used to generate the VIN_UV_FAULT flag.
4 Power conversion
stop delay
R/W Sets the delay time from when the VIN_LOW flag is set to when the power conversion stops.
0 = 0 ms.
1 = 1 ms.
[3:2] Power conversion
start delay
R/W Sets the delay time from the clearing of the VIN_LOW flag to the start of the power conversion.
Bit 3 Bit 2 Delay Time (ms)
0 0 0
0 1 10
1
0
40
1 1 80
[1:0] VIN_UV_FAULT flag
debounce
R/W When Bit 5 is set, sets the VIN_UV_FAULT flag debounce time.
Bit 1 Bit 0 Typical Debounce Time (ms)
0 0 0
0 1 2.5
1 0 10
1 1 100
Rev. A | Page 88 of 108
Data Sheet ADP1051
TEMPERATURE SENSE AND PROTECTION SETTING REGISTERS
Table 135. Register 0xFE2A—RTD Gain Trim
Bits Bit Name/Function R/W Description
7
Gain polarity
R/W
Setting this bit to 1 means that negative gain is introduced. Setting this bit to 0 means that
positive gain is introduced.
[6:0] RTD gain trim R/W This value calibrates the RTD sensing gain.
Table 136. Register 0xFE2B—RTD Offset Trim (MSBs)
Bits Bit Name/Function R/W Description
[7:3]
Reserved
R/W
Reserved.
2 RTD current source
disable
R/W Setting this bit to 1, plus the writing value 0x00 to register 0xFE2D, disables the RTD current source.
1 Trim polarity R/W Setting this bit to 1 means that negative offset is introduced. Setting this bit to 0 means that
positive offset is introduced.
0 RTD offset trim, MSB R/W This bit, together with Register 0xFE2C as the LSBs, sets the amount of offset trim that is applied to
the RTD ADC reading.
Table 137. Register 0xFE2C—RTD Offset Trim (LSBs)
Bits Bit Name/Function R/W Description
[7:0] RTD offset trim, LSBs R/W These eight bits, together with Bit 0 in Register 0xFE2B as the MSB, set the amount of offset trim
that is applied to the RTD ADC reading.
Table 138. Register 0xFE2D—RTD Current Source Settings
Bits Bit Name/Function R/W Description
[7:6]
RTD current setting
R/W
These bits set the size of the current source on the RTD pin.
Bit 7 Bit 6 Current Source (µA)
0 0 10
0 1 20
1 0 30
1
1
40
[5:0] RTD current trim R/W These six bits are used to trim the current source on the RTD pin. Each LSB corresponds to 160 nA,
independent of the RTD current setting selected in Bits[7:6].
Table 139. Register 0xFE2F—OT Hysteresis Settings
Bits Bit Name/Function R/W Description
[7:3]
Reserved
R/W
Reserved.
2 OT_WARNING flag
debounce
R/W This bit sets the OT_WARNING flag debounce time.
0 = sets the flag actions debounce time to 100 ms.
1 = sets the flag actions debounce time to 0 ms.
[1:0] OT hysteresis R/W These bits set the OT hysteresis. Due to the negative temperature coefficient of the NTC thermistor or
analog temperature sensor, the OT_FAULT flag clearing voltage threshold is programmed with a
voltage greater than the OT_FAULT flag setting voltage threshold.
Bit 1 Bit 0 OT Hysteresis
0 0 OT hysteresis = 12.5 mV (4 LSBs)
0 1 OT hysteresis = 25 mV (8 LSBs)
1 0 OT hysteresis = 37.5 mV (12 LSBs)
1 1 OT hysteresis = 50 mV (16 LSBs)
Rev. A | Page 89 of 108
ADP1051 Data Sheet
DIGITAL COMPENSATOR AND MODULATION SETTING REGISTERS
POLE LOCATION
RANGE
ZERO
ZERO
RANGE
LF GAI N RANGE
48.13dB
48.13dB
100Hz 500Hz 1kHz 5kHz 10kHz
11443-065
HF GAIN
RANGE
POLE
48.13dB
LF FILTER
HF FILTER
Figure 66. Digital Compensator Programmability
Table 140. Register 0xFE30—Normal Mode Compensator Low Frequency Gain Settings
Bits Bit Name/Function R/W Description
[7:0]
Normal mode low
frequency gain
R/W
This register determines the low frequency gain of the digital compensator in normal mode. It is
programmable over a 48.13 dB range. See Figure 66.
Table 141. Register 0xFE31—Normal Mode Compensator Zero Settings
Bits Bit Name/Function R/W Description
[7:0] Normal mode
zero settings
R/W This register determines the position of the zero of the digital compensator in normal mode.
See Figure 66.
Table 142. Register 0xFE32—Normal Mode Compensator Pole Settings
Bits Bit Name/Function R/W Description
[7:0] Normal mode
pole settings
R/W This register determines the position of the pole of the digital compensator in normal mode.
See Figure 66.
Table 143. Register 0xFE33—Normal Mode Compensator High Frequency Gain Settings
Bits Bit Name/Function R/W Description
[7:0]
Normal mode high
frequency gain
R/W
This register determines the high frequency gain of the digital compensator in normal mode. It is
programmable over a 48.13 dB range. See Figure 66.
Table 144. Register 0xFE34—Light Load Mode Compensator Low Frequency Gain Settings
Bits Bit Name/Function R/W Description
[7:0] Light load mode low
frequency gain
R/W This register determines the low frequency gain of the digital compensator in light load mode and
deep light load mode. It is programmable over a 48.13 dB range. See Figure 66.
Table 145. Register 0xFE35—Light Load Mode Compensator Zero Settings
Bits Bit Name/Function R/W Description
[7:0] Light load mode
zero setting
R/W This register determines the position of the zero of the digital compensator in light load mode and
deep light load mode. See Figure 66.
Table 146. Register 0xFE36—Light Load Mode Compensator Pole Settings
Bits Bit Name/Function R/W Description
[7:0] Light load mode
pole setting
R/W This register determines the position of the pole of the digital compensator in light load mode and
deep light load mode. See Figure 66.
Table 147. Register 0xFE37—Light Load Mode Compensator High Frequency Gain Settings
Bits Bit Name/Function R/W Description
[7:0] Light load mode
high frequency gain
R/W This register determines the high frequency gain of the digital compensator in light load mode and
deep light load mode. It is programmable over a 48.13 dB range. See Figure 66.
Rev. A | Page 90 of 108
Data Sheet ADP1051
Table 148. Register 0xFE38—CS1 Threshold for Volt-Second Balance
Bits Bit Name/Function R/W Description
[7:0] CS1 threshold for
volt-second balance
R/W This register sets the CS1 threshold to enable volt-second balance control. The volt-second balance
control function is activated only if the CS1 value is greater than this threshold value. Each LSB is
6.25 mV.
Table 149. Register 0xFE39—Nominal Modulation Value for Pre-Bias Startup
Bits Bit Name/Function R/W Description
[7:0] Nominal modulation
value for pre-bias
start-up function
R/W These bits set the nominal modulation value when the input voltage and the output voltage are in
nominal conditions. It is used to calculate the initial modulation value, based on the sensed VOUT value
and the sensed VIN value, for the pre-bias startup. If Register 0xFE6C[1] is cleared, the input voltage is
always regarded as the nominal input condition unless closed-loop feedforward operation is in use.
Switching Frequency Range (kHz) Resolution Corresponding to LSB (ns)
49 to 87 80
97.5 to 184 40
195.5 to 379 20
390.5 to 625 10
Table 150. Register 0xFE3A—Constant Current Speed and SR Driver Delay
Bits Bit Name/Function R/W Description
[7:6] VS voltage change
rate during constant
current mode
R/W These bits set the VS voltage change rate when operating in constant current mode. The basic change
rate for a 9-bit CS2 averaging speed is 1.18 mV/ms. The basic change rate for a 7-bit CS2 averaging
speed is 4.72 mV/ms. These two bits set the change rate of the output voltage when operating in
constant current mode.
For example, in a 12 V output system, if Register 0xFE1B[4] = 1 and Register 0xFE3A[7:6] = 11,
the output voltage change rate is
4.72 mV/ms × 8 × 12 = 453 mV/ms
Bit 7 Bit 6 Change Rate (mV/ms)
0 0 1
0 1 2
1 0 4
1 1 8
[5:0] SR gate drive delay R/W These bits set the SR gate drive delay in steps of 5 ns. The maximum delay is 315 ns.
Table 151. Register 0xFE3B—PWM 180° Phase Shift Settings
Bits Bit Name/Function R/W Description
7 Volt-second balance
leading edge blanking
R/W Setting this bit means that CS1 is blanked for volt-second balance calculations at the rising edge of
those PWMs selected for volt-second balance. The blanking time is the same as for the CS1 cycle-
by-cycle current-limit setting.
6 Volt-second balance
50% blanking of each
phase
R/W Setting this bit limits the sampling period for the current on CS1 to less than 50% of a half cycle.
5 SR2 180° phase shift R/W Setting this bit adds a 180° phase shift for the timing of the SR2 edges.
4 SR1 180° phase shift R/W Setting this bit adds a 180° phase shift for the timing of the SR1 edges.
3 OUTD 180° phase shift R/W Setting this bit adds a 180° phase shift for the timing of the OUTD edges.
2 OUTC 180° phase shift R/W Setting this bit adds a 180° phase shift for the timing of the OUTC edges.
1 OUTB 180° phase shift R/W Setting this bit adds a 180° phase shift for the timing of the OUTB edges.
0 OUTA 180° phase shift R/W Setting this bit adds a 180° phase shift for the timing of the OUTA edges.
Rev. A | Page 91 of 108
ADP1051 Data Sheet
Figure 67 and Register 0xFE3C describe the modulation limit settings.
t
RX
t
FX
t
RY
t
FY
t
0, START OF
SWIT CHING CY CLE
t
S/2
t
S
, END OF
SWITCHING CYCLE 3
t
S/2
OUTx
OU
TY
t
MODU_LIMIT
t
MODU_LIMIT
11443-066
Figure 67. Setting Modulation Limits
Table 152. Register 0xFE3C—Modulation Limit
Bits Bit Name/Function R/W Description
[7:0] Modulation limit R/W This register sets the modulation limit, tMODU_LIMIT (maximum duty cycle). The modulation
limit is the maximum time variation for the modulated edges from the default timing
(see Figure 67). The step size of an LSB depends on the switching frequency.
Switching Frequency Range (kHz) LSB Step Size (ns)
49 to 87 80
97.5 to 184
40
195.5 to 379 20
390.5 to 625 10
Table 153. Register 0xFE3D—Feedforward and Soft Start Filter Gain
Bits Bit Name/Function R/W Description
7 Soft start enable of open-loop
input voltage feedforward
operation
R/W Setting this bit enables the soft start procedure of the open-loop input voltage
feedforward operation.
Bit 6 should be set if this function is used.
6 Open-loop input voltage
feedforward operation enable
R/W 0 = open-loop input voltage feedforward operation is disabled.
1 = open-loop input voltage feedforward operation is enabled.
5 High frequency ADC debounce
time
R/W This bit sets the debounce time for detecting the settling of the VS high frequency ADC.
Bit 4 must be set to 1 to enable this function.
0 = 5 ms debounce time.
1 = 10 ms debounce time.
4 High frequency ADC debounce
enable
R/W Setting this bit enables a debounce time for detecting the settling of the VS high frequency
ADC at the end of a soft start. The debounce time is set using Bit 5.
3 Feedforward ADC selection R/W Always set this bit to select the 11-bit VF ADC (factory default setting).
2 Feedforward enable R/W This bit enables or disables feedforward control during closed-loop operation.
0 = closed-loop input voltage feedforward control is disabled.
1 = closed-loop input voltage feedforward control is enabled.
[1:0] Soft start filter gain R/W These bits set the soft start gain of the soft start filter.
Bit 1 Bit 0 Soft Start Filter Gain
0 0 1
0 1 2
1 0 4
1 1 8
Rev. A | Page 92 of 108
Data Sheet ADP1051
PWM OUTPUTS TIMING REGISTERS
Figure 68 and Register 0xFE3E to Register 0xFE53 describe the implementation and programming of the six PWM signals that are
generated by the ADP1051.
OUTA
OUTB
OUTC
OUTD
SR1
SR2
t
F1
t
R1
t
F2
t
R2
t
F3
t
R3
t
F4
t
R4
t
F5
t
R5
t
F6
t
R6
t
PERIOD
t
PERIOD
11443-067
Figure 68. PWM Timing Diagram
Table 154. Register 0xFE3E/41/44/47/4A/4D—OUTA/OUTB/OUTC/OUTD/SR1/SR2 Rising Edge Timing
Bits Bit Name/Function R/W Description
[7:0] Rising edge timing, tRx,
MSBs
R/W This register contains the eight MSBs of the 12-bit tRx time. This value is always used with the top
four bits of Register 0xFE40, Register 0xFE43, Register 0xFE46, Register 0xFE49, Register 0xFE4C,
and Register 0xFE4F, which contain the four LSBs of the tRx time.
tRx represents tR1, tR2, tR3, tR4, tR5, and tR6. Each LSB corresponds to 5 ns resolution.
Table 155. Register 0xFE3F/42/45/48/4B/4E—OUTA/OUTB/OUTC/OUTD/SR1/SR2 Falling Edge Timing
Bits Bit Name/Function R/W Description
[7:0] Falling edge timing, tFx,
MSBs
R/W This register contains the eight MSBs of the 12-bit tFx time. This value is always used with the
bottom four bits of Register 0xFE40, Register 0xFE43, Register 0xFE46, and Register 0xFE49, as
well as Register 0xFE4C and Register 0xFE4F, which contain the four LSBs of the tFx time.
tFx represents tF1, tF2, tF3, tF4, tF5, and tF6. Each LSB corresponds to 5 ns resolution.
Table 156. Register 0xFE40/43/46/49/4C/4F—OUTA/OUTB/OUTC/OUTD/SR1/SR2 Rising and Falling Edge Timing (LSBs)
Bits
Bit Name/Function
R/W
Description
[7:4] Rising edge timing, tRx,
LSBs
R/W These bits contain the four LSBs of the 12-bit tRx time. This value is always used with the eight bits of
Register 0xFE3E, Register 0xFE41, Register 0xFE44, and Register 0xFE47, as well as Register 0xFE4A
and Register0xFE4D, which contain the eight MSBs of the tRx time.
tRx represents tR1, tR2, tR3, tR4, tR5, and tR6. Each LSB corresponds to 5 ns resolution.
[3:0]
Falling edge timing, t
Fx
,
LSBs
R/W
These bits contain the four LSBs of the 12-bit t
Fx
time. This value is always used with the eight bits
of Register 0xFE3F, Register 0xFE42, Register 0xFE45, and Register 0xFE48, as well as Register 0xFE4B
and Register 0xFE4E, which contain the eight MSBs of the tFx time.
tFx represents tF1, tF2, tF3, tF4, tF5, and tF6. Each LSB corresponds to 5 ns resolution.
Rev. A | Page 93 of 108
ADP1051 Data Sheet
Table 157. Register 0xFE50—OUTA and OUTB Modulation Settings
Bits Bit Name/Function R/W Description
7 OUTB tR2 modulation enable R/W 0 = no PWM modulation of the tR2 edge.
1 = PWM modulation acts on the tR2 edge.
6 OUTB tR2 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tR2 to the right.
1 = negative sign. Increase of PWM modulation moves tR2 to the left.
5 OUTB tF2 modulation enable R/W 0 = no PWM modulation of the tF2 edge.
1 = PWM modulation acts on the tF2 edge.
4
OUTB t
F2
modulation sign
R/W
0 = positive sign. Increase of PWM modulation moves t
F2
to the right.
1 = negative sign. Increase of PWM modulation moves tF2 to the left.
3 OUTA tR1 modulation enable R/W 0 = no PWM modulation of the tR1 edge.
1 = PWM modulation acts on the tR1 edge.
2 OUTA tR1 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tR1 to the right.
1 = negative sign. Increase of PWM modulation moves tR1 to the left.
1 OUTA tF1 modulation enable R/W 0 = no PWM modulation of the tF1 edge.
1 = PWM modulation acts on the tF1 edge.
0 OUTA tF1 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tF1 to the right.
1 = negative sign. Increase of PWM modulation moves tF1 to the left.
Table 158. Register 0xFE51—OUTC and OUTD Modulation Settings
Bits
Bit Name/Function
R/W
Description
7 OUTD tR4 modulation enable R/W 0 = no PWM modulation of the tR4 edge.
1 = PWM modulation acts on the tR4 edge.
6 OUTD tR4 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tR4 to the right.
1 = negative sign. Increase of PWM modulation moves tR4 to the left.
5 OUTD tF4 modulation enable R/W 0 = no PWM modulation of the tF4 edge.
1 = PWM modulation acts on the tF4 edge.
4 OUTD tF4 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tF4 to the right.
1 = negative sign. Increase of PWM modulation moves tF4 to the left.
3 OUTC tR3 modulation enable R/W 0 = no PWM modulation of the tR3 edge.
1 = PWM modulation acts on the t
R3
edge.
2 OUTC tR3 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tR3 to the right.
1 = negative sign. Increase of PWM modulation moves tR3 to the left.
1 OUTC tF3 modulation enable R/W 0 = no PWM modulation of the tF3 edge.
1 = PWM modulation acts on the tF3 edge.
0 OUTC tF3 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tF3 to the right.
1 = negative sign. Increase of PWM modulation moves tF3 to the left.
Table 159. Register 0xFE52—SR1 and SR2 Modulation Settings
Bits Bit Name/Function R/W Description
7 SR2 tR6 modulation enable R/W 0 = no PWM modulation of the tR6 edge.
1 = PWM modulation acts on the tR6 edge.
6 SR2 tR6 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tR6 to the right.
1 = negative sign. Increase of PWM modulation moves tR6 to the left.
5 SR2 tF6 modulation enable R/W 0 = no PWM modulation of the tF6 edge.
1 = PWM modulation acts on the tF6 edge.
4 SR2 tF6 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tF6 to the right.
1 = negative sign. Increase of PWM modulation moves t
F6
to the left.
3 SR1 tR5 modulation enable R/W 0 = no PWM modulation of the tR5 edge.
1 = PWM modulation acts on the tR5 edge.
2 SR1 tR5 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tR5 to the right.
1 = negative sign. Increase of PWM modulation moves tR5 to the left.
1 SR1 tF5 modulation enable R/W 0 = no PWM modulation of the tF5 edge.
1 = PWM modulation acts on the tF5 edge.
0 SR1 tF5 modulation sign R/W 0 = positive sign. Increase of PWM modulation moves tF5 to the right.
1 = negative sign. Increase of PWM modulation moves tF5 to the left.
Rev. A | Page 94 of 108
Data Sheet ADP1051
Table 160. Register 0xFE53—PWM Output Disable
Bits Bit Name/Function R/W Description
[7:6] Reserved R/W Reserved.
5 SR2 disable R/W Setting this bit disables the SR2 output.
4 SR1 disable R/W Setting this bit disables the SR1 output.
3 OUTD disable R/W Setting this bit disables the OUTD output.
2 OUTC disable R/W Setting this bit disables the OUTC output.
1 OUTB disable R/W Setting this bit disables the OUTB output.
0 OUTA disable R/W Setting this bit disables the OUTA output.
VOLT-SECOND BALANCE CONTROL REGISTERS
Table 161. Register 0xFE54—Volt-Second Balance Control General Settings
Bits Bit Name/Function R/W Description
7 Volt-second balance enable control R/W Setting this bit enables volt-second balance control.
6 Volt-second balance control
source selection, OUTD
R/W If this bit is set, the OUTD rising edge is selected as the start of the integration period
for volt-second balance control.
5 Volt-second balance control
source selection, OUTC
R/W If this bit is set, OUTC rising edge is selected as the start of the integration period for
volt-second balance control.
4 Volt-second balance control
source selection, OUTB
R/W If this bit is set, OUTB rising edge is selected as the start of the integration period for
volt-second balance control.
3 Volt-second balance control
source selection, OUTA
R/W If this bit is set, OUTA rising edge is selected as the start of the integration period for
volt-second balance control.
2 Volt-second balance control limit R/W This bit sets the maximum amount of modulation from the volt-second control circuit.
0 = ±160 ns.
1 = ±80 ns.
[1:0] Volt-second balance control gain R/W These bits set the gain of the volt-second balance control. The gain can be changed by
a factor of 64. When these bits are set to 00, it takes approximately 700 ms to achieve
volt-second balance. When these bits are set to 11, it takes approximately 10 ms to
achieve volt-second balance.
Bit 1 Bit 0 Volt-Second Balance Loop Gain
0 0 1
0
1
4
1 0 16
1 1 64
Table 162. Register 0xFE55—Volt-Second Balance Control on OUTA and OUTB
Bits Bit Name/Function R/W Description
7 tR2 balance setting R/W Setting this bit enables modulation from balancing control on the OUTB rising edge, tR2.
6 tR2 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tR2 right.
1 = negative sign. Increase of balancing control modulation moves tR2 left.
5 tF2 balance setting R/W Setting this bit enables modulation from balancing control on the OUTB falling edge,
tF2.
4 tF2 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tF2 right.
1 = negative sign. Increase of balancing control modulation moves tF2 left.
3 tR1 balance setting R/W Setting this bit enables modulation from balancing control on the OUTA rising edge,
tR1.
2 tR1 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tR1 right.
1 = negative sign. Increase of balancing control modulation moves tR1 left.
1 tF1 balance setting R/W Setting this bit enables modulation from balancing control on the OUTA falling edge,
tF1.
0 tF1 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tF1 right.
1 = negative sign. Increase of balancing control modulation moves tF1 left.
Rev. A | Page 95 of 108
ADP1051 Data Sheet
Table 163. Register 0xFE56—Volt-Second Balance Control on OUTC and OUTD
Bits Bit Name/Function R/W Description
7 tR4 balance setting R/W Setting this bit enables modulation from balancing control on the OUTD rising edge, tR4.
6
t
R4
balance setting
R/W
0 = positive sign. Increase of balancing control modulation moves t
R4
right.
1 = negative sign. Increase of balancing control modulation moves tR4 left.
5 tF4 balance setting R/W Setting this bit enables modulation from balancing control on the OUTD falling edge, tF4.
4 tF4 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tF4 right.
1 = negative sign. Increase of balancing control modulation moves tF4 left.
3 tR3 balance setting R/W Setting this bit enables modulation from balancing control on the OUTC rising edge, tR3.
2 tR3 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tR3 right.
1 = negative sign. Increase of balancing control modulation moves tR3 left.
1
t
F3
balance setting
R/W
Setting this bit enables modulation from balancing control on the OUTC falling edge, t
F3
.
0 tF3 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tF3 right.
1 = negative sign. Increase of balancing control modulation moves tF3 left.
Table 164. Register 0xFE57—Volt-Second Balance Control on SR1 and SR2
Bits Bit Name/Function R/W Description
7 tR6 balance setting R/W Setting this bit enables modulation from balancing control on the SR2 rising edge, tR6.
6 tR6 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tR6 right.
1 = negative sign. Increase of balancing control modulation moves tR6 left.
5 tF6 balance setting R/W Setting this bit enables modulation from balancing control on the SR2 falling edge, tF6.
4 tF6 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tF6 right.
1 = negative sign. Increase of balancing control modulation moves tF6 left.
3
t
R5
balance setting
R/W
Setting this bit enables modulation from balancing control on the SR1 rising edge, t
R5
.
2 tR5 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tR5 right.
1 = negative sign. Increase of balancing control modulation moves tR5 left.
1 tF5 balance setting R/W Setting this bit enables modulation from balancing control on the SR1 falling edge, tF5.
0 tF5 balance direction R/W 0 = positive sign. Increase of balancing control modulation moves tF5 right.
1 = negative sign. Increase of balancing control modulation moves tF5 left.
DUTY CYCLE READING SETTING REGISTERS
Table 165. Register 0xFE58—Duty Cycle Reading Settings
Bits Bit Name/Function R/W Description
[7:6] Reserved R/W Reserved.
5
OUTD duty cycle reporting
R/W
1 = READ_DUTY_CYCLE reports OUTD duty cycle value.
4 OUTC duty cycle reporting R/W 1 = READ_DUTY_CYCLE reports OUTC duty cycle value.
3 OUTB duty cycle reporting R/W 1 = READ_DUTY_CYCLE reports OUTB duty cycle value.
2 OUTA duty cycle reporting R/W 1 = READ_DUTY_CYCLE reports OUTA duty cycle value.
1
Duty cycle reporting for
phase-shifted topology
R/W
Setting this bit enables duty cycle reporting for phase-shifted full bridge topology. The duty cycle
value represents the overlapping of OUTA and OUTD in the phase-shifted full bridge topology.
0 Polarity setting for input
voltage compensation
R/W Setting this bit applies an offset on the input voltage reading, READ_VIN, based on the reading of
the input current, READ_IIN. The compensation multipler is set in Register 0xFE59. It is used to
compensate the voltage drop caused by the current conduction.
0 = positive polarity compensation.
1 = negative polarity compensation.
Table 166. Register 0xFE59—Input Voltage Compensation Multiplier
Bits Bit Name/Function R/W Description
[7:0] Input voltage compensation
multiplier
R/W These bits specify the multiplier, N, for the input voltage compensation coefficient. The
compensation equation is N × (Register 0xFEA7[15:4] value) ÷ 211, and the result is added to
Register 0xFEAC[15:5]. The compensation polarity is set by Register 0xFE58[0].
Rev. A | Page 96 of 108
Data Sheet ADP1051
ADAPTIVE DEAD TIME COMPENSATION REGISTERS
Table 167. Register 0xFE5A—Adaptive Dead Time Compensation Threshold
Bits Bit Name/Function R/W Description
[7:0]
Adaptive dead time
compensation
threshold
R/W
This register sets the adaptive dead time compensation threshold. The 8-bit number is compared to the
8 MSBs of the CS1 value register (Register 0xFEA7). When the CS1 current falls below this threshold, the
edges of the PWM signals are affected as a linear function of the CS1 current, as programmed in
Register 0xFE5B to Register 0xFE60. When the register is programmed to 0x00, the adaptive dead
time compensation function is disabled.
Table 168. Register 0xFE5B—OUTA Dead Time
Bits Bit Name/Function R/W Description
7 tR1 polarity R/W 0 = positive polarity; 1 = negative polarity.
[6:4] tR1 offset multiplier R/W This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tR1 offset from
nominal timing at 0 A input current.
Bit 6 Bit 5 Bit 4 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0
1
1
3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
3 tF1 polarity R/W 0 = positive polarity; 1 = negative polarity.
[2:0] tF1 offset multiplier R/W This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tF1 offset from
nominal timing at 0 A input current.
Bit 2 Bit 1 Bit 0 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0
1
1
3
1 0 0 4
1 0 1 5
1 1 0 6
1
1
1
7
Table 169. Register 0xFE5C—OUTB Dead Time
Bits
Bit Name/Function
R/W
Description
7 tR2 polarity R/W 0 = positive polarity; 1 = negative polarity.
[6:4] tR2 offset multiplier This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tR2 offset from
nominal timing at 0 A input current .
Bit 6 Bit 5 Bit 4 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
3 tF2 polarity R/W 0 = positive polarity; 1 = negative polarity.
Rev. A | Page 97 of 108
ADP1051 Data Sheet
Bits Bit Name/Function R/W Description
[2:0] tF2 offset multiplier R/W This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tF2 offset from
nominal timing at 0 A input current.
Bit 2 Bit 1 Bit 0 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
Table 170. Register 0xFE5D—OUTC Dead Time
Bits Bit Name/Function R/W Description
7 tR3 polarity R/W 0 = positive polarity; 1 = negative polarity.
[6:4]
t
R3
offset multiplier
This value multiplies the step size specified by Register 0xFE66[2:0] to determine the t
R3
offset from
nominal timing at 0 A input current.
Bit 6 Bit 5 Bit 4 Multiplier
0 0 0 0
0 0 1 1
0
1
0
2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
3 tF3 polarity R/W 0 = positive polarity; 1 = negative polarity.
[2:0] tF3 offset multiplier R/W This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tF3 offset from
nominal timing at 0 A input current.
Bit 2 Bit 1 Bit 0 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0 1 1 3
1 0 0 4
1 0 1 5
1
1
0
6
1 1 1 7
Table 171. Register 0xFE5E—OUTD Dead Time
Bits Bit Name/Function R/W Description
7 tR4 polarity R/W 0 = positive polarity; 1 = negative polarity.
[6:4]
t
R4
offset multiplier
This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tR4 offset from
nominal timing at 0 A input current.
Bit 6 Bit 5 Bit 4 Multiplier
0 0 0 0
0 0 1 1
0
1
0
2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
3 tF4 polarity R/W 0 = positive polarity; 1 = negative polarity.
Rev. A | Page 98 of 108
Data Sheet ADP1051
Bits Bit Name/Function R/W Description
[2:0] tF4 offset multiplier R/W This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tF4 offset from
nominal timing at 0 A input current.
Bit 2 Bit 1 Bit 0 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
Table 172. Register 0xFE5F—SR1 Dead Time
Bits Bit Name/Function R/W Description
7 tR5 polarity R/W 0 = positive polarity; 1 = negative polarity.
[6:4]
t
R5
offset multiplier
This value multiplies the step size specified by Register 0xFE66[2:0] to determine the t
R5
offset from
nominal timing at 0 A input current.
Bit 6 Bit 5 Bit 4 Multiplier
0 0 0 0
0 0 1 1
0
1
0
2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
3 tF5 polarity R/W 0 = positive polarity; 1 = negative polarity.
[2:0] tF5 offset multiplier R/W This value multiplies the step size specified by Register 0xFE66[2:0]to determine the tF5 offset from
nominal timing at 0 A input current.
Bit 2 Bit 1 Bit 0 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0 1 1 3
1 0 0 4
1 0 1 5
1
1
0
6
1 1 1 7
Table 173. Register 0xFE60—SR2 Dead Time
Bits Bit Name/Function R/W Description
7 tR6 polarity R/W 0 = positive polarity; 1 = negative polarity.
[6:4]
t
R6
offset multiplier
This value multiplies the step size specified by Register 0xFE66[2:0] to determine the t
R6
offset from
nominal timing at 0 A input current.
Bit 6 Bit 5 Bit 4 Multiplier
0 0 0 0
0 0 1 1
0
1
0
2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1
1
1
7
3 tF6 polarity R/W 0 = positive polarity; 1 = negative polarity.
Rev. A | Page 99 of 108
ADP1051 Data Sheet
Bits Bit Name/Function R/W Description
[2:0] tF6 offset multiplier R/W This value multiplies the step size specified by Register 0xFE66[2:0] to determine the tF6 offset from
nominal timing at 0 A input current.
Bit 2 Bit 1 Bit 0 Multiplier
0 0 0 0
0 0 1 1
0 1 0 2
0 1 1 3
1 0 0 4
1 0 1 5
1 1 0 6
1 1 1 7
OTHER REGISTER SETTINGS
Table 174. Register 0xFE61—GO Commands
Bits Bit Name/Function R/W Description
[7:3] Reserved R/W Reserved.
2 Frequency go R/W This bit synchronously latches the contents of Register 0x33 into the shadow registers used to
calculate the switching frequency. Reading of this bit always returns 1.
1 PWM setting go R/W This bit synchronously latches the contents of Registers 0xFE3E to Register 0xFE53 into the shadow
registers used to calculate the PWM edge timing. Reading this bit always returns 1.
0 Reserved R/W Reserved.
Table 175. Register 0xFE62—Customized Register
Bits Bit Name/Function R/W Description
[7:0] Customized register R/W These bits are available to the user to store customized information.
Table 176. Register 0xFE63—Modulation Reference MSBs Setting for Open-Loop Input Voltage Feedforward Operation
Bits Bit Name/Function R/W Description
[7:0] Modulation
reference setting
MSBs
R/W This register sets the eight MSBs of the modulation reference in open-loop feedforward operation mode.
The step size of an LSB depends on the switching frequency.
Switching Frequency Range (kHz) LSB Step Size (ns)
49 to 87 80
97.5 to 184 40
195.5 to 379
20
390.5 to 625 10
Table 177. Register 0xFE64—Modulation Reference LSBs Setting for Open-Loop Input Voltage Feedforward Operation
Bits
Bit Name/Function
R/W
Description
[7:0] Modulation
reference setting
LSBs
R/W This register sets the eight LSBs of the modulation reference in open-loop feedforward operation mode.
The step size of an LSB depends on the switching frequency.
Switching Frequency Range (kHz) LSB Step Size (ps)
49 to 87 312.5
97.5 to 184 156.25
195.5 to 379
78.125
390.5 to 625 39.0625
Rev. A | Page 100 of 108
Data Sheet ADP1051
Table 178. Register 0xFE65—Current Value Update Rate Setting
Bits Bit Name/Function R/W Description
[7:2] Reserved R/W Reserved.
[1:0]
Current value
update rate
R/W
These bits specify the update rate for the current value of CS1 (READ_IIN command, Register 0x89)
and CS2 (READ_IOUT command, Register 0x8C). By default, the current values are updated every 10 ms.
Bit 1 Bit 0 CS1, CS2 Value Update Rate (ms)
0 0 10 (defaut)
0 1 52
1 0 105
1 1 210
Table 179. Register 0xFE66—Adaptive Dead Time Compensation Configuration
Bits Bit Name/Function R/W Description
[7:6] Averaging period R/W These bits specify the averaging period for the CS1 current used to set the adaptive dead time. It is
recommended that the averaging time be set to a value much greater than any transient condition.
Bit 7 Bit 6 Averaging Period (ms)
0 0 2.5
0 1 1.2
1 0 0.6
1 1 0.3
[5:3] Update rate R/W The adaptive dead time compensation algorithm adjusts dead time in steps of 5 ns. These bits are
used to program the number of PWM switching cycles between each steps. The number is calculated as
2N + 1, where N is the 3-bit value specified by these bits. For example, if N = 6 (110 binary), each PWM
edge is adjusted by 5 ns every 26 + 1 = 65 switching cycles.
[2:0]
Offset step size
R/W
These bits specify the programming step size for Register 0xFE5B to Register 0xFE60, Bits[6:4] and Bits[2:0].
Bit 2 Bit 1 Bit 0 LSB Step Size (ns)
0 0 0 5
0 0 1 10
0 1 0 15
0
1
1
20
1 0 0 25
1 0 1 30
1 1 0 35
1 1 1 40
Table 180. Register 0xFE67—Open-Loop Operation Settings
Bits Bit Name/Function R/W Description
7 Reserved R Reserved.
6 Pulse skipping mode enable R/W 1 = enables the pulse skipping mode. If the ADP1051 requires a modulation value that
is less than the threshold set by Register 0xFE69, pulse skipping is in use.
5 SR2 open-loop operation enable R/W This bit is set when SR2 is used in open-loop operation mode.
4 SR1 open-loop operation enable R/W This bit is set when SR1 is used in open-loop operation mode.
3 OUTD open-loop operation enable R/W This bit is set when OUTD is used in open-loop operation mode.
2 OUTC open-loop operation enable R/W This bit is set when OUTC is used in open-loop operation mode.
1 OUTB open-loop operation enable R/W This bit is set when OUTB is used in open-loop operation mode.
0 OUTA open-loop operation enable R/W This bit is set when OUTA is used in open-loop operation mode.
Table 181. Register 0xFE68—Offset Setting for SR1 and SR2
Bits Bit Name/Function R/W Description
[7:0] The offset setting for SR1/SR2 R/W If SR_RC_FAULT flag is triggered and Register 0xFE03[7:6] = 11, these bits set the
offset value (tOFFSET) on the SR1 and SR2 rising edges. The rising edges are moved
left from tRx + tMODU_LIMIT by tOFFSET. Each step corresponds to 5 ns.
Rev. A | Page 101 of 108
ADP1051 Data Sheet
Table 182. Register 0xFE69—Pulse Skipping Mode Threshold
Bits Bit Name/Function R/W Description
[7:0] Pulse skipping mode
threshold
R/W These bits set the modulation pulse width threshold for pulse skipping. Each LSB is 5 ns.
Table 183. Register 0xFE6A—CS3_OC_FAULT_LIMIT
Bits Bit Name/Function R/W Description
[7:0] CS3_OC_FAULT_LIMIT R/W The eight MSB value of the CS3 value register in Register 0xFEA9 is compared with this 8-bit
number. If the 8 MSB value is greater, the CS3_OC_FAULT flag is set.
Table 184. Register 0xFE6B—Modulation Threshold for OVP Selection
Bits Bit Name/Function R/W Description
[7:0]
Modulation threshold
for conditional
OVP responses
R/W
This value sets modulation threshold for conditional OVP response. When the real-time modu-
lation value is above this threshold, the LARGE_MODULATION flag in Register 0xFE6C[2] is set.
Switching Frequency Range (kHz) Resolution Corresponding to LSB (ns)
49 to 87 80
97.5 to 184 40
195.5 to 379 20
390.5 to 625 10
Table 185. Register 0xFE6C—Modulation Flag for OVP Selection
Bits Bit Name/Function R/W Description
[7:3] Reserved R/W Reserved.
2 LARGE_MODULATION R This bit is set when the modulation value is above the threshold set in Register 0xFE6B.
1 VIN feedforward
pre-bias startup
R/W This bit is applicable only if the closed-loop feedforward operation is disabled (Register 0xFE3D[2] = 0).
If the closed-loop feedforward operation is enabled, VIN is always included for the calculation of
the initial PWM modulation value.
1 = the initial PWM modulation value is calculated by the nominal modulation value (Register 0xFE39),
the sensed VIN voltage, and the sensed VOUT voltage.
0 = the initial PWM modulation value is calculated by the nominal modulation value (Register 0xFE39)
and the sensed VOUT voltage. The VIN voltage is ignored.
0 Conditional OVP
enable
R/W This bit sets the OVP actions when the VOUT_OV_FAULT flag is triggered.
0 = conditional OVP is disabled. The OVP action follows the PMBus VOUT_OV_FAULT_RESPONSE
command (Register 0x41).
1 = conditional OVP is enabled. If Bit 2 = 1, OVP action follows the PMBus VOUT_OV_FAULT_RESPONSE
(Register 0x41). If Bit 2 = 0, OVP action follows the extended VOUT_OV_FAULT_RESPONSE action
(Register 0xFE01[7:4]).
Table 186. Register 0xFE6D—OUTA and OUTB Adjustment Reference During Synchronization
Bits Bit Name/Function R/W Description
7 tR2 adjustment reference R/W Setting this bit enables edge adjustment on the OUTB rising edge, tR2
6 tR2 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
5 tF2 adjustment reference R/W Setting this bit enables edge adjustment on the OUTB falling edge, tF2.
4 tF2 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
3
t
R1
adjustment reference
R/W
Setting this bit enables edge adjustment on the OUTA rising edge, t
R1
.
2 tR1 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
1
t
F1
adjustment reference
R/W
Setting this bit enables edge adjustment on the OUTA falling edge, t
F1
.
0 tF1 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
Rev. A | Page 102 of 108
Data Sheet ADP1051
Table 187. Register 0xFE6E—OUTC and OUTD Adjustment Reference During Synchronization
Bits Bit Name/Function R/W Description
7 tR4 adjustment reference R/W Setting this bit enables edge adjustment on the OUTD rising edge, tR4.
6
t
R4
refers to t
S
or t
S
/2
R/W
0 = adjustment refers to t
S
/2.
1 = adjustment refers to tS.
5 tF4 adjustment reference R/W Setting this bit enables edge adjustment on the OUTD falling edge, tF4.
4 tF4 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
3 tR3 adjustment reference R/W Setting this bit enables edge adjustment on the OUTC rising edge, tR3.
2 tR3 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
1
t
F3
adjustment reference
R/W
Setting this bit enables edge adjustment on the OUTC falling edge, t
F3
.
0 tF3 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
Table 188. Register 0xFE6F—SR1 and SR2 Adjustment Reference During Synchronization
Bits Bit Name/Function R/W Description
7
t
R6
adjustment reference
R/W
Setting this bit enables edge adjustment on the SR2 rising edge, t
R6
.
6 tR6 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
5 tF6 adjustment reference R/W Setting this bit enables edge adjustment on the SR2 falling edge, tF6.
4 tF6 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
3
t
R5
adjustment reference
R/W
Setting this bit enables edge adjustment on the SR1 rising edge, t
R5
.
2 tR5 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
1 tF5 adjustment reference R/W Setting this bit enables edge adjustment on the SR1 falling edge, tF5.
0 tF5 refers to tS or tS/2 R/W 0 = adjustment refers to tS/2.
1 = adjustment refers to tS.
Register 0xFE70 to Register 0xFE9F—Reserved
Rev. A | Page 103 of 108
ADP1051 Data Sheet
MANUFACTURER SPECIFIC FAULT FLAG REGISTERS
Table 189. Register 0xFEA0—Flag Register 1 and Register 0xFEA3—Latched Flag Register 1 (1 = Fault, 0 = Normal Operation)
Bits Bit Name/Function R/W Description Register Action
7
CHIP_PASSWORD_UNLOCKED
R
Chip password is unlocked.
None
6 PGOOD R At least one of the following flags has been set:
VOUT_OV_FAULT, VOUT_UV_FAULT, IOUT_OC_FAULT,
OT_FAULT, OT_WARNING, VIN_UV_FAULT, IIN_OC_
FAST_FAULT, SR_RC_FAULT, POWER_OFF, CRC_FAULT,
SOFT_START_FILTER, or POWER_GOOD. Some of the flags
are maskable according to Register 0xFE0D
0xFE0D
and
0xFE0E
PG/ALT pin
set low
5 IIN_OC_FAST_FAULT R An input overcurrent fast fault is triggered. 0xFE1F Programmable
4 Reserved R Reserved.
3 CS3_OC_FAULT R A CS3 overcurrent fault is triggered. 0xFE6A Programmable
2 Reserved R Reserved.
1 Reserved R Reserved.
0 VDD_OV R VDD is above the OVLO limit. The I2C/PMBus interface
remains functional, but power conversion stops.
0xFE05 Programmable
Table 190. Register 0xFEA1—Flag Register 2 and Register 0xFEA4—Latched Flag Register 2 (1 = Fault, 0 = Normal Operation)
Bits Bit Name/Function R/W Description Register1 Action1
7 Reserved R Reserved. N/A N/A
6 Reserved R Reserved. N/A N/A
5 SR_RC_FAULT R CS2 reverse current drops below SR_RC_FAULT_LIMIT. 0xFE1A Programmable
4 CONSTANT_CURRENT R Constant current mode is in use. 0xFE1A,
0xFE1B
Programmable
3 LIGHT_LOAD R Light load mode (CS2 current is below the light load
threshold).
0xFE19 Programmable
2 VIN_UV_FAULT R VIN reading is below the VIN_OFF limit. 0xFE29 Programmable
1 SYNC_LOCKED R Cycle-by-cycle synchronization starts. N/A Programmable
0 FLAGIN R FLAGIN flag (SYNI/FLGI pin) is set. 0xFE12 Programmable
1 N/A means not applicable.
Table 191. Register 0xFEA2—Flag Register 3 and Register 0xFEA5—Latched Flag Register 3 (1 = Fault, 0 = Normal Operation)
Bits Bit Name/Function R/W Description Register1 Action1
7 CHIP_ID R In the ADP1051, this bit is 1. N/A N/A
6 PULSE_SKIPPIING R Pulse skipping mode is in use. 0xFE69 Programmable
5
ADAPTIVE_DEAD_TIME
R
Adaptive dead time compensation is in use.
0xFE66
Programmable
4 DEEP_LIGHT_LOAD R Deep light load mode (CS2 current is below the deep light
load threshold).
0xFE1B Programmable
3 EEPROM_UNLOCKED R The EEPROM is unlocked. N/A None
2 CRC_FAULT R The EEPROM contents that were downloaded are incorrect. N/A Immediate
shutdown
1
Modulation
R
Digital compensator output is at its minimum or maximum
limit.
N/A
None
0 SOFT_START_FILTER R The soft start filter is in use. N/A None
1 N/A means not applicable.
Rev. A | Page 104 of 108
Data Sheet ADP1051
Table 192. Register 0xFEA6—First Flag ID
Bits Bit Name/Function R/W Description
[7:4] Previous first flag ID R These bits return the flag fault ID of the flag that caused the previous shutdown of the power
supply. This previous shutdown occurred before the shutdown caused by the fault identified
in Bits[3:0].
Bit 3 Bit 2 Bit 1 Bit 0 First Flag
0 0 0 0 No flag
0 0 0 1 IIN_OC_FAST_FAULT
0 0 1 0 IOUT_OC_FAULT
0 0 1 1 CS3_OC_FAULT
0
1
0
0
VOUT_OV_FAULT
0 1 0 1 VOUT_UV_FAULT
0 1 1 0 VIN_UV_FAULT
0 1 1 1 FLAGIN
1 0 0 0 SR_RC_FAULT
1 0 0 1 OT_FAULT
1
0
1
0
Reserved
1 0 1 1 Reserved
1 1 0 0 Reserved
1 1 0 1 Reserved
1 1 1 0 Reserved
1 1 1 1 Reserved
[3:0] Current first flag ID R These bits return the flag fault ID of the fault that caused the shutdown of the power supply.
Bit 3 Bit 2 Bit 1 Bit 0 First Flag
0 0 0 0 No flag
0 0 0 1 IIN_OC_FAST_FAULT
0 0 1 0 IOUT_OC_FAULT
0 0 1 1 CS3_OC_FAULT
0 1 0 0 VOUT_OV_FAULT
0
1
0
1
VOUT_UV_FAULT
0 1 1 0 VIN_UV_FAULT
0 1 1 1 FLAGIN
1 0 0 0 SR_RC_FAULT
1 0 0 1 OT_FAULT
1 0 1 0 Reserved
1 0 1 1 Reserved
1 1 0 0 Reserved
1 1 0 1 Reserved
1 1 1 0 Reserved
1 1 1 1 Reserved
Rev. A | Page 105 of 108
ADP1051 Data Sheet
MANUFACTURER SPECIFIC VALUE READING REGISTERS
Table 193. Register 0xFEA7—CS1 Value
Bits Bit Name/Function R/W Description
[15:4]
CS1 current value
R
This register contains 12-bit CS1 current information. The range of the CS1 input pin is from 0 V
to 1.6 V. Each LSB corresponds to 390.625 μV. At 0 V input, the value in this register is 0 decimal.
The nominal voltage at this pin is 1 V.
At 1 V input, the value in these bits is 0xA00 (2560 decimal).
The reading is equivalent to the READ_IIN command.
[3:0] Reserved R Reserved.
Table 194. Register 0xFEA8—CS2 Value
Bits Bit Name/Function R/W Description
[15:4] CS2 voltage value R This register contains the 12-bit CS2 output current information. The range of the CS2± input
pins is from 0 mV to 120 mV. Each LSB corresponds to 29.297 μV.
At 0 V input, the value in this register is 0.
The reading is equivalent to the READ_IOUT command.
[3:0] Reserved R Reserved.
Table 195. Register 0xFEA9—CS3 Value
Bits Bit Name/Function Type Description
[15:4] CS3 voltage value R This register contains 12-bit CS3 current information calculated by using the CS1 reading and
duty cycle information. Each LSB corresponds to 4× the CS1 LSB in Register 0xFEA7, multiplied
by the turn ratio of the main transformer, n (n = NPRI/NSEC).
[3:0] Reserved R Reserved.
Table 196. Register 0xFEAA—VS Value
Bits Bit Name/Function R/W Description
[15:4]
VS voltage value
R
This register contains the 12-bit VS± output voltage information. The range of the VS± input
pins is from 0 V to 1.6 V. Each LSB corresponds to 390.625 μV.
At 0 V input, the value in this register is 0. The nominal voltage at the VS+ and VS− pins is 1 V.
At 1 V input, the value in these bits of this register is 0xA00 (2560 decimal).
The reading is equivalent to the READ_VOUT command.
[3:0] Reserved R Reserved.
Table 197. Register 0xFEAB—RTD Value
Bits Bit Name/Function R/W Description
[15:4] RTD temperature value R These bits contain the 12-bit RTD temperature information, as determined from the RTD pin.
The range of the RTD input pin is from 0 V to 1.6 V. Each LSB corresponds to 390.625 μV.
At 0 V input, the value in this register is 0. The nominal voltage at the RTD pin is 1 V.
At 1 V input, the value in these bits is 0xA00 (2560 decimal).
[3:0] Reserved R Reserved.
Table 198. Register 0xFEAC—VF Value
Bits Bit Name/Function R/W Description
[15:5] VF voltage value R This register contains the 11-bit VF voltage information. The range of the VF input pin is from 0 V
to 1.6 V. Each LSB corresponds to 781.25 μV.
At 0 V input, the value in this register is 0. The nominal voltage at the VF pin is 1 V.
At 1 V input, the value in these bits is 0x500 (1280 decimal).
The reading is equivalent to the READ_VIN command.
[4:0] Reserved R Reserved.
Table 199. Register 0xFEAD—Duty Cycle Value
Bits Bit Name/Function R/W Description
[15:12] Reserved R Reserved.
[11:0] Duty cycle value R This register contains the 12-bit duty cycle information. Each LSB corresponds to 0.0244% duty
cycle. At 100% duty cycle, the value in these bits is 0xFFF (4095 decimal).
Rev. A | Page 106 of 108
Data Sheet ADP1051
Table 200. Register 0xFEAE—Input Power Value
Bits Bit Name/Function R/W Description
[15:0] Input power value R This register contains the 16-bit input power information. This value is the product of the input
voltage value (VF) and input current value (CS1). The product of two 12-bit values is a 24-bit
value, and the eight LSBs are discarded.
Table 201. Register 0xFEAF—Output Power Value
Bits Bit Name/Function R/W Description
[15:0] Output power value R This register contains the 16-bit output power information. This value is the product of the
output voltage value (VS) and the output current reading (CS2). The product of two 12-bit
values is a 24-bit value, and the eight LSBs are discarded.
Rev. A | Page 107 of 108
ADP1051 Data Sheet
OUTLINE DIMENSIONS
0.50
BSC
0.50
0.40
0.30
0.30
0.25
0.18
COMPLIANT
TO
JEDEC S TANDARDS M O-220- WG GD.
04-12-2012-A
BOTTO M VI EWTOP VI EW
EXPOSED
PAD
PI N 1
INDICATOR
4.10
4.00 S Q
3.90
SEATING
PLANE
0.80
0.75
0.70
0.20 RE F
0.25 M IN
COPLANARITY
0.08
PI N 1
INDICATOR
2.65
2.50 S Q
2.45
1
24
7
12
13
1819
6
FOR PROPE R CONNECTI ON O F
THE EXPOSED PAD, REFER TO
THE P IN CO NFI GURAT IO N AND
FUNCTI ON DES CRIPTI ONS
SECTION OF THIS DATA SHEET.
0.05 M AX
0.02 NOM
Figure 69. 24-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
4 mm × 4 mm Body, Very Very Thin Quad
(CP-24-7)
Dimensions shown in millimeters
ORDERING GUIDE
Model1 Temperature Range Package Description Package Option
ADP1051ACPZ-RL −40°C to +125°C 24-Lead Lead Frame Chip Scale Package [LFCSP_WQ] CP-24-7
ADP1051ACPZ-R7 −40°C to +125°C 24-Lead Lead Frame Chip Scale Package [LFCSP_WQ] CP-24-7
ADP1051-240-EVALZ
240 W Evaluation Board for ADP1051 and ADP1050
ADP1051DC1-EVALZ ADP1051 Daughter Card
ADP-I2C-USB-Z USB to I2C Adapter
1 Z = RoHS Compliant Part.
I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).
©2013–2014 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D11443-0-6/14(A)
Rev. A | Page 108 of 108
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