NCP5230 Precise Low Voltage Synchronous Buck Controller with Power Saving Mode http://onsemi.com MARKING DIAGRAMS 1 5230 A L Y W G Features * * * * Desktop and Server Systems *For additional information on our Pb-Free strategy and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D. May, 2012 - Rev. 0 VCC ROSC/EN CSP PIN CONNECTIONS 16 15 14 13 12 CSN/VO LG 2 11 FBG LX 3 10 VSEN BOOT 4 9 FB 5 1 6 7 8 COMP 1 SYNC VCCP (Top View) ORDERING INFORMATION Device NCP5230MNTWG Applications (c) Semiconductor Components Industries, LLC, 2012 (*Note: Microdot may be in either location) PGOOD High Performance Operational Error Amplifier Internal Soft-Start/Stop 0.5% Internal Voltage Accuracy, 0.8 V voltage reference OCP accuracy, Four Re-entry Times Before Latch "Lossless" Differential Inductor Current Sensing Internal High Precision Current Sensing Amplifier Oscillator Frequency Range of 100 kHz - 1000 kHz 20 ns Adaptive FET Non-overlap Time of Internal Gate Driver 5.0 V to 12 V Operation Support 1.5 V to 19 V Vin Vout from 0.8 V to 3.3 V (5 V with 12 VCC) Chip Enable through OSC pin Latched Over Voltage Protection (OVP) Internally Fixed OCP Threshold Guaranteed Startup Into Pre-Charged Loads Thermally Compensated Current Monitoring Thermal Shutdown Protection Integrated MOSFET Drivers Integrated BOOST Diode with internal Rbst = 2.2 W Automatic Power Saving Mode to Maximize Efficiency During Light Load Operation Sync Function Remote Ground Sensing This is a Pb-Free Device* = Specific Device Code = Assembly Location = Wafer Lot = Year = Work Week = Pb-Free Package UG * * * * * * * * * * * * * * * * * * * * 5230 ALYWG G QFN16 CASE 485G GND The NCP5230 is a simple single phase solution with differential phase current sensing, power saving operation, and gate drivers to provide accurately regulated power. The adaptive non overlap gate drive and power saving operation circuit provide a low switching loss and high efficiency solution for server, notebook, and desktop systems. A high performance operational error amplifier is provided to simplify compensation of the system. The NCP5230 features also include soft-start sequence, accurate overvoltage and over current protection, UVLO for VCC and VCCP, and thermal shutdown. Package Shipping QFN16 3000 / Tape & Reel (Pb-Free) For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D. Publication Order Number: NCP5230/D VCC PGOOD NCP5230 15 6 2.2 W Over Current Detector CSP 13 4 BOOT 5 UG 3 LX 1 VCCP 2 LG CDIFF + - Current Sense Amplifier CSN/VO 12 - COMP 8 FBG 11 VREF*75% UVP Control Logic, Protection, RAMP Generator and PWM Logic + + 0.8V - Error Amplifier FB 9 + VREF*125% 1.24V SYNC 7 Programmable VREF*50% UVLO Control OVP - - VSEN 10 ROSC/EN 14 OSC OVP, UNLATCHED + OSC 16 GND Figure 1. NCP5230 BLOCK DIAGRAM PIN DESCRIPTIONS Pin No. Symbol Description 1 VCCP 2 LG Bottom gate MOSFET driver pin 3 LX Switch node 4 BOOT Power supply for bottom gate MOSFET drivers Supply rail for the floating top gate driver 5 UG 6 PGOOD 7 SYNC Synchronization Pin. The controller synchronizes on the falling edge of a square wave provided to this pin. Short to GND if not used. 8 COMP Output of the error amplifier 9 FB 10 VSEN Output Voltage Sense 11 FBG Remote Ground Sense 12 CSN/VO 13 CSP 14 ROSC/EN 15 VCC Supply rail for the controller internal circuitry GND Ground reference 16 THERMAL PAD Top gate MOSFET driver pin Power Good. It is an open-drain output, set free after SS (with 3x clock delay) as long as the output voltage monitored through VSEN is within specifications. Inverting input to the error amplifier Inductor differential sense inverting input Inductor differential sense non-inverting input Programs the switching frequency; EN: Pull-low to disable the device Connects with the silicon substrate for good thermal contact with the PCB. Connect to GND plane. http://onsemi.com 2 NCP5230 11 CFB2 9 8 2 VCC FB LX COMP CH1 CF1 10 RVFB1 UG FBG VSEN RF1 RFB3 CBOOT1 CSP NCP5230 CSN/VO LG LOUT1 5 3 Q4 2 1 ENABLE JP3 2 R2 VOUT 3 12 1 4 + COUT1 2 13 BOOT Q3 1 ROSC1 RS4 SYNC VCCP ROSC/EN 7 CSEN1 GND RSEN1 PGOOD 16 6 RS3 RISO1 RFB2 VIN 15 RNTC1 14 SYNC VCCP 3 VCC PGOOD 1 ETCH R1 Figure 2. Typical Application Circuit ABSOLUTE MAXIMUM RATINGS Rating Symbol VMAX VMIN Unit VCC, VCCP 15 -0.3 V BOOT 35V wrt/GND 40 V <100 ns wrt/GND 15 wrt/LX -0.3 V High-Side Driver Output (Top Gate) UG 35 40 V 50 ns wrt/GND 15 wrt/LX -0.3 wrt/LX -5 V < 200 ns V Switching Node (Bootstrap Supply Return) LX 35 40 < 100 ns -5 -10 V < 200 ns V Low-Side Driver Output (Bottom Gate) LG 15 -0.3 -5 V < 200 ns V 6 -0.3, -1 V < 1 ms V PGOOD 7 -0.3, -1 V < 1 ms V SYNC 7 -0.3, -1 V < 1 ms V CSP, CSN/VO with VCC = 12 V 10 -0.3, -1 V < 1 ms V Controller Power Supply Voltages to GND Boost Supply Voltage Input All Other Pins PGOOD SYNC Current Sense Amplifier Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. *All signals referenced to GND unless noted otherwise. http://onsemi.com 3 NCP5230 THERMAL INFORMATION Symbol Typ Unit Thermal Resistance, Junction-to-Ambient Rating RqJA 60 C/W Thermal Resistance, Junction-to-Case RqJC 18 C/W Operating Junction Temperature Range TJ 0 to 125 C Operating Ambient Temperature Range TA 0 to 85 C Maximum Storage Temperature Range TSTG -55 to +150 C Moisture Sensitivity Level MSL 1 - QFN Package ELECTRICAL CHARACTERISTICS Unless otherwise stated: 0C < TA < 85C; 4.5 V < VCC < 13.2 V; CVCC = 0.1 mF Parameter Test Conditions Min Typ Max Unit SUPPLY OPERATING CONDITIONS VCC Voltage Range 4.5 13.2 V VCCP Voltage Range 4.5 13.2 V dV/dt on VCC (Note 1) -10 10 V/ms dV/dt on VCCP (Note 1) -10 10 V/ms VCC AND BOOT INPUT SUPPLY CURRENT VCC Operating Current VCC = 5 V, EN = High VCC = 12 V, EN = High 5.0 mA VCC Supply Current VCC = 5 V, EN = Low VCC = 12 V, EN = Low 400 uA VCCP INPUT SUPPLY CURRENT VCCP Operating Current UG and LG Open VCCP = 5 V, EN = High VCCP = 12 V, EN = High VCCP Supply Current VCCP = 5 V, EN = Low VCCP = 12 V, EN = Low 200 mA VCC Rising 4.50 V 3.5 5.0 mA VCC SUPPLY VOLTAGE VCC UVLO Start Threshold VCC UVLO Hysteresis VCC Rising or Falling 300 mV VCCP SUPPLY VOLTAGE 4.2 VCCP UVLO Start Threshold VCCP UVLO Hysteresis V 200 mV 120 dB 18 MHz 8.0 V/ms 0.800 V ERROR AMPLIFIER COMP Open Loop DC Gain (Note 1) Open Loop Unity Gain Bandwidth (Note 1) Slew Rate (Note 1) 15 COMP pin to GND with 100 pF load VREF Internal Reference Voltage Output Voltage Accuracy Vout to FBG excluding external resistor divider tolerance -0.5 0.5 % Common Mode Input Voltage Range (Note 1, GNG, output within 10mV) VCC 7.5 V -0.3 3.5 V Common Mode Input Voltage Range (Note 1, GNG, output within 10 mV) VCC > 7.5 V -0.3 5.5 V CURRENT SENSE AMPLIFIERS 1. Guaranteed by design. 2. For propagation delays, "tpdh" refers to the specified signal going high "tpdl" refers to it going low. Reference Gate Timing Diagram. http://onsemi.com 4 NCP5230 ELECTRICAL CHARACTERISTICS Unless otherwise stated: 0C < TA < 85C; 4.5 V < VCC < 13.2 V; CVCC = 0.1 mF Parameter Test Conditions Min Typ Max Unit 10 % OSCILLATOR (with no ROSC Resistor Defaults to 200 kHz) Switching Frequency Accuracy ROSC open -10 OSC Gain (Note 1) Disable threshold 10 ROSC/EN pin, Vdis_th kHz / mA 0.75 V MODULATORS (PWM Comparators) Minimum Pulse Width Fsw = 200 kHz, OSC open Minimum Turn Off Time (LG on) Fsw = 200 kHz, OSC open 90 250 Magnitude of the PWM Ramp VIN = 5 V or 12 V Maximum Duty Cycle OSC/EN = OPEN 80 In light load, maximum time for LG to turn on after HG turns off 30 Minimum Skip mode frequency 350 ns 450 ns 95 % 1.50 V kHz SOFT-START Soft Start Time @ 200 kHz 1024 clock cycles, OSC/EN open 5.12 ms Rdis 120 W SOFT-OFF Soft OFF bleeding resistor OVER CURRENT PROTECTION First Over Current Threshold Second Over Current Threshold CSP-CSN, 4xMasking 17 CSP-CSN, Immediate action 20 23 30 mV mV SYNC PIN Synchronization Input VIL, square wave Synchronization Input VIH, square wave 1.0 2.5 V V PROTECTION AND PGOOD Output Voltage Logic Low, Sinking 4 mA 0.4 V OVP Threshold VSEN rising above 1.25 * Vref 117 125 130 % UVP Threshold VSEN falling below 0.75 * Vref 70 75 80 % Vth_disoff with respect to 0.5 Vref 40 50 60 % Power Good High Delay (Note 1) 50 ms Power Good Low Delay (Note 1) 1 ms 40 ns 20 ns Unlatched Overvoltage Threshold ZERO CURRENT DETECTION (LX Pin) Blanking Time before Zero Current Detection (Note 1) Capture Time for LX Voltage (Note 1) Blanking Time after LG is < 1.0 V Time to capture LX voltage once LG is < 1.0 V (must be within dead time limits) Negative LX detection voltage Vbdls 150 300 450 mV Positive LX detection voltage Vbdhs 0.2 0.5 1.0 V 300 kHz 3.0 3.7 ms Time for Vth adjustment and settling time (Note 1) Initial Negative Current Detection Threshold Voltage Set Point (Note 1) LX-GND, Includes 2 mV Offset Range Vth adjustable Range (Note 1) 1.0 -16 0 mV 15 mV 1. Guaranteed by design. 2. For propagation delays, "tpdh" refers to the specified signal going high "tpdl" refers to it going low. Reference Gate Timing Diagram. http://onsemi.com 5 NCP5230 ELECTRICAL CHARACTERISTICS Unless otherwise stated: 0C < TA < 85C; 4.5 V < VCC < 13.2 V; CVCC = 0.1 mF Parameter Test Conditions Min Typ Max Unit VBOOT - VLX = 12 V, Cload = 3 nF 2.5 5 W VBOOT - VLX = 12V 2.0 2.5 W TrDRVH Transition Time CLOAD = 2 nF 16 TfDRVH Transition Time CLOAD = 2 nF 11 Driving High, CLOAD = 3 nF, VCC = 12 V, VCCP =12 V 15 Unbiased, BOOT - LX = 0 45 VLX = GND, Cload = 3 nF 2.0 3.0 W VLX = VCC 1.0 1.5 W TrDRVL Transition Time CLOAD = 3 nF 16 TfDRVL Transition Time CLOAD = 3 nF 11 HIGH SIDE DRIVER UG RH_TG Output Resistance, Sourcing RH_TG Output Resistance, Sinking TpdhDRVH Propagation Delay (Notes 1, 2) UG Internal Resistor to LX ns 30 ns kW LOW SIDE DRIVER LG RH_BG Output Resistance, Sourcing RL_BG Output Resistance, Sinking TpdhDRVL Propagation Delay (Notes 1, 2) Driving High, CLOAD = 3 nF, VCCP = 12 V, VCCP = 12 V 10 LX Internal Resistor to GND 20 ns 35 ns 45 kW 180 C 50 C THERMAL SHUTDOWN Tsd Thermal Shutdown (Note 1) 150 Tsdhys Thermal Shutdown Hysteresis (Note 1) 1. Guaranteed by design. 2. For propagation delays, "tpdh" refers to the specified signal going high "tpdl" refers to it going low. Reference Gate Timing Diagram. http://onsemi.com 6 NCP5230 1V 1V Figure 3. Gate Timing Diagram Switching Frequency of an internal ramp signal correspondingly with a fixed delay time. The external signal has to sit within a 0-40% frequency window above the local frequency configured by the Rosc resistor to allow the synchronization function working properly. Connecting a resistor from ROSC/EN to an external voltage source Vpu will configure the switching frequency. Normal range would be 100 kHz to 1 MHz. With no resistor connected to the pin, the oscillator frequency is 200 kHz. The switching frequency will follow the relationship: V pu * 1.240 kHz mA Power Good When Rosc = infinity (no resistor connected), Fsw = 200 kHz; when Vpu = ground, the frequency programmed will be higher than 200 kHz. Pulling Rosc/EN pin to ground solidly with a less than 10 kW resistor will result in the part being disabled. The PGOOD pin is an open drain connection with no internal pullup resistor. An active high output signals the normal operation of the converter. PGOOD is pulled low during soft-start cycle, and if there is an overvoltage or undervoltage fault. If the voltage on the VSEN pin is within 10% of Vref (0.8 V) then the PGOOD pin will not be pulled low. Soft-Start Overvoltage Protection (OV) F SW + 200 kHz * R OSC @ 10 (eq. 1) If the voltage on the VSEN pin exceeds the overvoltage threshold (1000 mV or 125% Vref), the NCP5230 will latch an overvoltage fault. During an overvoltage fault event the UG pin will be pulled low, and the LG pin will stay high until the voltage on the VSEN pin goes below 400 mV or 50% Vref, then a soft-bleeding resistor will be connected from switch node to ground to continuously discharge the output voltage softly. To clear the overvoltage fault, toggling VCC or EN is needed. Soft-Start will begin if VCC, VCCP are both above their UVLO thresholds and EN pin is set free. IC initially waits a fixed delay time and then ramps the reference in 5.12 ms (1024 clock cycles when Rosc open) in closed-loop regulation. After soft-start, PGOOD signal will be released with 3 clock cycles delay. Protection active during soft-start: * Overvoltage Protection always enabled; * Undervoltage Protection is enabled after reference voltage ramps up to 80% of the final value. During soft-start, a UVP fault will initiate a complete soft restart. Undervoltage Protection (UV) If the voltage on the FB pin falls below the undervoltage threshold after the softstart cycle completes, the NCP5230 will latch an undervoltage fault. During an undervoltage fault, both the UG and LG pins will be pulled low. Toggling VCC power or EN will reset the undervoltage protection. Synchronization Function Synchronize through the SYNC pin. Synchronization function allows different converters to share the same input filter reducing the resulting RMS current and reducing the need for total caps to sustain the load. Synchronized systems also exhibit higher EMI noise immunity and better regulation. The device synchronizes to the Falling edge of the SYNC pin external input signal (eg. high side gate signal, switch node signal, distribution clock signal), and locks the phase PreOVP Protection If the NCP5230 is powered on but not enabled, the VSEN pin will be monitored for preOVP condition. If the VSEN exceeds the preset threshold, the device will force LG pin high to protect the load. The PreOVP function will be disabled when the device is enabled and the normal OV function will operate instead. http://onsemi.com 7 NCP5230 VPU LG BUFFER VSEN VTH Figure 4. PreOVP circuit Vin Detection OCP2 will be tripped, the UG and LG will be pulled low and latched immediately. Toggling VCC power or EN will reset the Overcurrent protection. The current sensing R/C network should be selected to match the inductor time constant as below, During the soft start after the VSEN pin exceeds 80% Vref, UV protection will be enabled; If a UV fault is triggered in the softstart, it will restart SS after a fixed delay. The UV protection is to avoid IC to startup without Vin or with insufficient Vin voltage. (RCS1RCS2) @ C + Overcurrent Protection L DCR (Notes: the actual RC network time constant may be slightly higher) Thus, OCP1 and OCP2 levels can be configured as, NCP5230 measures the differential current sensing signal through CSP and CSN/VO pin. There are two current protection levels: OCP1 and OCP2. If the differential voltage across pin CSP and CSN/VO is over 20 mV (but below 30 mV) for four consecutive cycles, OCP1 will be tripped. Both UG and LG will be forced to low to turn off the high side and low side FETs, it is a latched condition; If the differential voltage across pin CSP and CSN is over 30 mV, http://onsemi.com 8 OCP1 + 20 mV RCS1 ) RCS2 @ DCR RCS2 OCP2 + 30 mV RCS1 ) RCS2 @ DCR RCS2 NCP5230 L RS1 DCR RS2 CS CSP CSN/VO Figure 5. Differential Current Sense Network Light Load Operation this way, the ripple variation during transition between the discontinuous and continuous current mode can be minimized. In the light load condition, NCP5230 will work in a diode emulation mode with bottom gate turning off if the inductor current is below zero. The system therefore works in discontinuous conduction mode (DCM). The zero current detection is done by sensing switch node and automatically adjusted to minimize the low side FET body diode conduction time (right after LG turns off) in diode emulation mode. If the load reduces further, COMP signal will be close or below the internal ramp bottom triggering minimum on time operation, the system will start skipping pulses, working in a reduced frequency range. NCP5230 has an internal ultrasonic timer to keep the device from working in an audio frequency and below. This timer initiates after high side gate off signal and expires after ~30 ms. Normally high side gate signal will reset this ultrasonic timer repeatedly before it expires. In a very light load or load release, if there is no high side gate pulses until the timer expires, the low side MOSFET(s) will be forced to turn on to discharge the output. Through properly compensated network the comp signal will climb up to generate next burst of switching pulses and the converter will regulate the output voltage to its target level. This can last a few cycles or continuously depending on the system load level. In light load operation, if synchronization is enabled, NCP5230 will also check the SYNC pin input signal cycle by cycle. If the external sync signal is within the synchronization frequency range, the NCP5230 will interleave its switching pulses with it after a proper delay. In Voltage Feedback The NCP5230 allow the output voltage to be adjusted from 0.8 V to 5 V via an external resistor divider network (R1, R2). The controller will regulate the output voltage to maintain the FB pin voltage to 0.8 V reference voltage. The relation between the resistor divider network and the output voltage is as below; R2 + R1 @ V 0.8 V * 0.8 V out VOUT R1 VFB R2 Figure 6. Feedback Voltage http://onsemi.com 9 NCP5230 Vin POR_VCC UVLO_VCC VCC 1.24V OSC/EN 0.75V LG (Stays Low until first PWM pulse except in case of a Fault) UG OVP (125%Vref) Vref = 0.8 V 80% Vrer OCP/ Normal shutdown Vout. FB Vth_disoff (50%Vref) v v Softstop UV monitor SoftStart Normal 1024cycle ~5ms@200kHzz Pre-OVP valid Figure 7. Start Up and Shutdown Timing Diagram http://onsemi.com 10 NCP5230 PWR ON EN>Vdis_th No VCC> POR & VCCDR > UVLO _VCCDR (16- pin ) Yes PreOVP detection BG on VSEN >OV Vth VCC > POR & VCCDR > UVLO _ VCCDR BOOT >UVLO_BOOT No Yes Fosc detection Soft Start , Normal Operation OCP, OVP, UVP detection UV (after Vout reaches UV threshold in softstart ) OC OV UVP OVP TG OFF, BG OFF PGOOD=0 TG OFF, BG ON PGOOD =0 OCP After 4 times reentry for 1st threshod or immediately over 2nd threshold No Vout < Vth_disoff TG OFF, BG OFF Yes Vo discharge mode Yes 4 times reentry OVP Vcc