RTT DBT
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FEATURES DESCRIPTION
APPLICATIONS
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
SBS v1.1-COMPLIANT GAS GAUGE FORUSE WITH THE bq29312
•Provides Accurate Measurement of Available
The bq2084-V140 SBS-compliant gas gauge IC forCharge in Li-Ion and Li-Polymer Batteries
battery pack or in-system installation maintains anaccurate record of available charge in Li-ion or•Supports the Smart Battery Specification
Li-polymer batteries. The bq2084-V140 monitors(SBS) V1.1
capacity and other critical parameters of the battery•Integrated Time Base Removes Need for
pack and reports the information to the system hostExternal Crystal with Optional Crystal input
controller over a serial communication bus. It is•Works With the TI bq29312 Analog Front-End
designed to work with the bq29312 AFE protectionIC to maximize functionality and safety and minimize(AFE) Protection IC to Provide Complete Pack
component count and cost in smart battery circuits.Electronics for 7.2-V, 10.8-V or 14.4-V Battery
Using information from the bq2084-V140, the hostPacks With Few External Components
controller can manage remaining battery power to•Based on a Powerful Low-Power RISC CPU
extend the system run time as much as possible.Core With High-Performance Peripherals
The bq2084-V140 uses an integrating converter with•Integrated Flash Memory Eliminates the Need
continuous sampling for the measurement of batteryfor External Configuration EEPROM
charge and discharge currents. Optimized for•Uses 16-Bit Delta Sigma Converter for
coulomb counting in portable applications, theAccurate Voltage and Temperature
self-calibrating integrating converter has a resolutionMeasurements
better than 0.65-nVh and an offset measurementerror of less than 1-µV (typical). For voltage and•Measures Charge Flow Using a High
temperature reporting, the bq2084-V140 uses aResolution 16-Bit Integrating Converter
16-bit A-to-D converter. With the bq29312, the– Better Than 0.65-nVh of Resolution
onboard ADC also monitors the pack and individual– Self-Calibrating cell voltages in a battery pack and allows thebq2084-V140 to generate the control signals– Offset Error Less Than 1-µV
necessary to implement the cell balancing and the•Programmable Cell Modeling for Maximum
required safety protection for Li-ion and Li-polymerBattery Fuel Gauge Accuracy
battery chemistries.•Drives 3-, 4-, or 5-Segment LED Display for
The bq2084-V140 supports the Smart Battery DataRemaining Capacity Indication
(SBData) commands and charge-control functions. It•Available in a 38-Pin TSSOP (DBT) Package
communicates data using the System ManagementBus (SMBus) 2-wire protocol. The data availableinclude the battery's remaining capacity,temperature, voltage, current, and remaining•Notebook PCs
run-time predictions.•Medical and Test Equipment
The bq2084-V140 provides LED drivers and a•Portable Instrumentation
pushbutton input to depict remaining battery capacityfrom full to empty in 20%, 25%, or 33% incrementswith a 3-, 4-, or 5-segment display.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Copyright © 2005–2006, Texas Instruments IncorporatedProducts conform to specifications per the terms of the TexasInstruments standard warranty. Production processing does notnecessarily include testing of all parameters.
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DESCRIPTION (CONTINUED)
ABSOLUTE MAXIMUM RATINGS
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foamduring storage or handling to prevent electrostatic damage to the MOS gates.
The bq2084-V140 contains 1k bytes of internal data flash memory, which store configuration information. Theinformation includes nominal capacity and voltage, self-discharge rate, rate compensation factors, and otherprogrammable cell-modeling factors used to accurately adjust remaining capacity for use-conditions based ontime, rate, and temperature. The bq2084-V140 also automatically calibrates or learns the true battery capacity inthe course of a discharge cycle from programmable near full to near empty levels.
The bq29312 analog front-end (AFE) protection IC is used to maximize functionality and safety and minimizecomponent count and cost in smart battery circuits. The bq29312 AFE protection IC provides power to thebq2084-V140 from a 2-, 3-, or 4-series Li-ion cell stack, eliminating the need for an external regulator circuit.
ORDERING INFORMATION
PACKAGE
(1)T
A
38-PIN TSSOP (DBT)
(2)
36-PIN QFN (RTT)
(3)
–20 °C to 85 °C bq2084DBT-V140 bq2084RTT-V140
(1) For the most current package and ordering information, see the Package Option Addendum at the endof this document, or see the TI Web site at www.ti.com .(2) The bq2084DBT-V140 is available in tape and reel. Add an R suffix to the device type (e.g.,bq2084DBTR-V140) to order tape and reel version.(3) The bq2084RTT-V140 is available in tape and reel only. Add an T suffix to the device type (e.g.,bq2084RTTT-V140) to order mini tape and reel version.
over operating free-air temperature range unless otherwise noted
(1)
UNIT
Supply voltage range, V
DD
relative to V
SS
(2)
–0.3 V to 4.1 VOpen-drain I/O pins, V
(IOD)
relative to V
SS
(2)
–0.3 V to 6 VInput voltage range to all other pins, V
I
relative to V
Ss
(2)
–0.3 V to V
DD
+ 0.3 VT
A
Operating free-air temperature range –20 °C to 85 °CT
stg
Storage temperature range –65 °C to 150 °C
(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratingsonly, and functional operation of the device at these or any other conditions beyond those indicated under recommended operatingconditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.(2) V
SS
refers to the common node of V
(SSA)
, V
(SSD)
, and V
(SSP)
.
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ELECTRICAL CHARACTERISTICS
2.10
2.15
2.20
2.25
2.30
2.35
2.40
2.45
2.50
-20 -10 0 10 20 30 40 50 60 70 80 100
105
110
115
120
125
130
135
140
TA - Free-Air Temperature - °C
- Negative Going Input Threshold Voltage - V
POWER ON RESET BEHAVIOR
vs
FREE-AIR TEMPERATURE
VIT
VIT-
Vhys
Vhys- Hysterisis Voltage - mV
INTEGRATING ADC CHARACTERISTICS
PLL SWITCHING CHARACTERISTICS
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
V
DD
= 3 V to 3.6 V, T
A
= –20 °C to 85 °C unless otherwise noted
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
V
DD
Supply voltage VDDA and VDDD 3 3.3 3.6 VNo flash programmingI
DD
Operating mode current 380 µAor LEDs activeI
(SLP)
Low-power storage mode current Sleep mode 8 µAOutput voltage low SMBC, SMBD, SDATA, SCLK, SAFE, PU I
OL
= 0.5 mA 0.4V
OL
VLED1-LED5 I
OL
= 10 mA 0.4Input voltage low SMBC, SMBD, SDATA, SCLK, EVENT, PU,
–0.3 0.8PRES, PFINV
IL
VDISP –0.3 0.8Input voltage high SMBC, SMBD, SDATA, SCLK, EVENT,
2 6PU, PRES, PFINV
IH
VDISP 2 V
DD
+ 0.3V
(AI1)
Input voltage range VIN, TS V
SS
– 0.3 1.0 VV
(AI2)
Input voltage range SR1, SR2 V
SS
– 0.25 0.25 VZ
(AI1)
Input impedance SR1, SR2 –0.25 V to 0.25 V 2.5 M ΩZ
(AI2)
Input impedance VIN, TS 0 V–1 V 8 M Ω
POWER-ON RESET
V
IT+
Negative-going voltage input 2.1 2.3 2.5 VV
hys
Power-on reset hysteresis 50 125 200 mV
V
DD
= 3 V to 3.6 V, T
A
= –20 °C to 85 °C unless otherwise noted
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
V
(SR)
Input voltage range, V
(SR2)
and V
(SR1)
V
SR
= V
(SR2)
– V
(SR1)
–0.25 0.25 VV
(SROS)
Input offset 1 mVINL Integral nonlinearity error FAST = 0, –0.1 V to 0.8 x V
ref
0.004% 0.018%
V
DD
= 3 V to 3.6 V, T
A
= –20 °C to 85 °C unless otherwise noted
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
t
(SP)
Start-up time
(1)
±0.5% frequency error 2 5 ms
(1) The frequency error is measured from the trimmed frequency of the internal system clock, which is 128 x oscillator frequency, nominally4.194 MHz.
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OSCILLATOR
DATA FLASH MEMORY CHARACTERISTICS
REGISTER BACKUP
SMBus TIMING SPECIFICATIONS
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
V
DD
= 3 V to 3.6 V, T
A
= –20 °C to 85 °C (unless otherwise noted) (TYP: V
DD
= 3.3 V, T
A
= 25 °C)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ROSC = 100k –2% 0.5% 2%f
(eio)
Frequency error from 32.768 kHz
XCK1 = 12 pF XTAL –0.25% 0.25%f
(dio)
Frequency drift
(1)
ROSC = 100k, T
A
= 0 °C to 50 °C –1% 1%f
(sio)
ROSC = 100k 200 µsStart-up time
(2)f
(sxo)
XCK1 = 12 pF XTAL 250 ms
(1) The frequency drift is measured from the trimmed frequency at V
DD
= 3.3 V, T
A
= 25 °C.(2) The start-up time is defined as the time it takes for the oscillator output frequency to be ±1%
V
DD
= 3 V to 3.6 V, T
A
= –20 °C to 85 °C unless otherwise noted
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
t
DR
Data retention See
(1)
10 YearsFlash programming write-cycles See
(1)
20k Cyclest
(WORDPROG)
Word programming time See
(1)
2 msI
(DDPROG)
Flash-write supply current See
(1)
8 12 mA
(1) Specified by design. Not production tested.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
I
(RBI)
RBI data-retention input current V
RBI
> 2 V, V
DD
< V
IT
10 100 nAV
(RBI)
RBI data-retention voltage
(1)
1.3 V
(1) Specified by design. Not production tested.
V
DD
= 3 V to 3.6 V, T
A
= -20 °C to 85 °C unless otherwise noted
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
f
(SMB)
SMBus operating frequency Slave mode, SMBC 50% duty cycle 10 100 kHzf
(MAS)
SMBus master clock frequency Master mode, no clock low slave extend 51.2 kHzt
(BUF)
Bus free time between start and stop 4.7 µsT
(HD:STA)
Hold time after (repeated) start 4 µst
(SU:STA)
Repeated start setup time 4.7 µst
(SU:STO)
Stop setup time 4 µsReceive mode 0t
(HD:DAT)
Data hold time nsTransmit mode 300t
SU:DAT)
Data setup time 250 nst
(TIMEOUT)
Error signal/detect See
(1)
25 35 mst
(LOW)
Clock low period 4.7 µst
(HIGH)
Clock high period See
(2)
4 50 µst
LOW:SEXT)
Cumulative clock low slave extend time See
(3)
25 mst
LOW:MEXT
Cumulative clock low master extend time See
(4)
10 mst
f
Clock/data fall time (V
ILMAX
– 0.15 V) to (V
IHMIN
+ 0.15 V) 300 nst
r
Clock/data rise time 0.9 V
DD
to (V
ILMAX
– 0.15 V) 1000 ns
(1) The bq2084-V140 times out when any clock low exceeds t
(TIMEOUT)
.(2) t
(HIGH)
Max. is minimum bus idle time. SMBC = 1 for t > 50 ms causes reset of any transaction involving bq2084-V140 that is inprogress.
(3) t
(LOW:SEXT)
is the cumulative time a slave device is allowed to extend the clock cycles in one message from initial start to the stop.(4) t
(LOW:MEXT)
is the cumulative time a master device is allowed to extend the clock cycles in one message from initial start to the stop.
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SMBus TIMING DIAGRAMS
SYSTEM DIAGRAM
PowerManagement
LDO,TOUTandPowerModeControl
Pre-ChargeControl Fail-Safe
Protection
TemperatureMeasurement
<1%Error TINT
1kBytesof
UserFlash
32kHzClock
Generator
CellBalancing AlgorithmandControl
SBSv1.1Data SystemInterface
bq29312RAM/CommsValidation
1st LevelOC
Protection
1st LevelOVand
UVProtection
PackUnder
VoltagePower
ModeControl
CellandPack
Voltage
Measurement
CapacityPrediction<1%Error
Pres
SMBus
bq2084
PCHFETDrive
Pre-Charge
FETDrive CellBalancing
Drive
LDO,ThermOutputDriveandUVLO
System
Watchdog DelayCounters
RAMRegistersSystemInterface
PowerModeControl
VoltageLevelTranslator
bq29312
2-TierOvercurrentProtection
3.3V
T1
I2C
PFInput
Discharge/Charge/
Pre-ChargeFETs
2ndLevelOvervoltageProtection
Fuse
Pack+
Pack −
32kHz
SenseResistor
(5to30m )W
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
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PIN ASSIGNMENTS
SMBD 1
4
2
5
3
6
7
PU
VSSD VSSD
LED5 VSSD
LED3 CLKOUT
LED4 N/C
LED2 XCK1/VSSA
DISP VIN
PFIN TS
LED1 SMBC
MRST SAFE
EVENT N/C
SR2 VSSD
SR1 SDATA
VSSA RBI
VSSA VDDD
VDDA N/C
FILTSCLK
XCK2/ROSC PRES
8
9
36
10
35
11
34
12
33
13
32
14
31
15
30
16
29
17
28
18
27
26
23
25
22
24
21
20
19
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
VIN
TS
VSSA
PU
PRES
SCLK
NC
VDDD
RBI
SDATA
VSSD
SAFE
NC
NC
SMBC
SMBD
DISP
PFIN
VSSD
VSSD
NC
NC
CLKOUT
XCK1/VSSA
XCK2/ROSC
FILT
VDDA
VSSA
VSSA
SR1
SR2
MRST
EVENT
LED1
LED2
LED3
LED4
LED5
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
QFN (RTT)(TOP VIEW)TSSOP (DBT)(TOP VIEW)
Terminal Functions
TERMINAL
I/O DESCRIPTIONNO. NO.NAME
TSSOP QFN
DISP 17 2 I Display control for the LED drivers LED1 through LED5CLKOUT 35 20 O 32.768-kHz output to the bq29312FILT 32 17 I Analog input connected to the external PLL filterEVENT 25 10 I Input from bq29312 XALERT outputLED1 24 9 OLED2 23 8 OLED3 22 7 O LED display segments that each may drive an external LEDLED4 21 6 OLED5 20 5 OMRST 26 11 I Master reset input that forces the device into reset when held high7, 13, 14, 36,NC 21, 29, 35 – No connection37PFIN 18 3 I Active low input to detect secondary protector output statusPRES 5 27 I Active low input to sense system insertionPU 4 26 O Output to pull up the PRES pin for detectionRegister backup that provides backup potential to the bq2084-V140 dataRBI 9 31 I registers during periods of low operating voltage. RBI accepts a storagecapacitor or a battery input.SAFE 12 34 O Active low output for additional level of safety protection; e.g., fuse blow.SCLK 6 28 O Communication clock to the bq29312SDATA 10 32 I/O Data transfer to and from bq29312SMBus clock open-drain bidirectional pin used to clock the data transfer to andSMBC 15 36 I/O
from the bq2084-V140
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FUNCTIONAL DESCRIPTION
OSCILLATOR FUNCTION
SYSTEM PRESENT OPERATION
GENERAL OPERATION
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Terminal Functions (continued)
TERMINAL
I/O DESCRIPTIONNO. NO.NAME
TSSOP QFN
SMBus data open-drain bidirectional pin used to transfer address and data toSMBD 16 1 I/O
and from the bq2084-V140SR1 28 13 I
Connections for a small-value sense resistor to monitor the battery charge- anddischarge-current flowSR2 27 12 ITS 2 24 I Thermistor voltage input connection to monitor temperatureVDDA 31 16 I Positive supply for analog circuitryVDDD 8 30 I Positive supply for digital circuitry and I/O pinsVIN 1 25 I Single-cell voltage input from the bq29312VSSA 3, 29, 30 14, 15 I Negative supply for analog circuitryVSSD 11, 19, 38 4, 22, 23, 33 I Negative supply for digital circuitry32.768-kHz crystal oscillator input pin or connected to VSSA if the internalXCK1/VSSA 34 19 I
oscillator is used32.768-kHz crystal oscillator output pin or connected to a 100-k Ω, 50 ppm orXCK2/ROSC 33 18 O
better resistor if the internal oscillator is used
The oscillator of the bq2084-V140 can be set up for an internal or external operation. As the bq2084-V140powers up it automatically attempts to start the internal oscillator, but if a 100-k Ωresistor is not connected toROSC (pin 33), then it attempts to start the oscillator using an external 32.768-kHz crystal. Either the 100-k ΩROSC resistor OR the 12 pF 32.768-kHz crystal should be mounted, NOT both.
The performance of the internal oscillator depends on the tolerance of the 100-k Ωresistor connected betweenRSOC (pin 33) and VSSA (pin 34). It is recommended that this resistor be as close to the bq2084-V140 aspossible and that it has a specification of ±0.1% tolerance and ±50 ppm temperature drift or better. The 12-pFcrystal, if used, should also be placed as close to the XCK1 (pin 34) and XCK2 (pin 33) pins as possible. Thelayout of the PCB around these pins and components is also an additional contributing factor to oscillatorperformance degradation.
The average temperature drift error of the oscillator function over a learning charge or discharge cycleintroduces an equal capacity prediction error in a learned full charge capacity (FCC).
When the bq2084-V140 detects that the battery is inserted into the system via a low state on the PRES input,the bq2084-V140 enters normal operating mode and sets the PRES bit in PackStatus(). The discharge FETturns on within 250 ms of pack insertion. When the pack is removed from the system and the PRES input ishigh, then the bq2084-V140 enters the battery removed state and turns OFF the charge and discharge FETs,and enables the 0-V/precharging FET. If NR in Misc Config is set, then the PRES input can be left floating as itis not used.
The bq2084-V140 determines battery capacity by monitoring the amount of charge input or removed from arechargeable battery. In addition to measuring charge and discharge, the bq2084-V140 measures individual cellvoltages, pack voltage, temperature, and current, estimates battery self-discharge, and monitors the battery forlow-voltage thresholds using features of the bq29312 AFE device.
The bq2084-V140 measures charge and discharge activity by monitoring the voltage across a small-value seriessense resistor between the cell stack negative terminal and the negative terminal of the battery pack. Theavailable battery charge is determined by monitoring this voltage and correcting the measurement forenvironmental and operating conditions.
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MEASUREMENTS
CHARGE AND DISCHARGE COUNTING
OFFSET CALIBRATION
DIGITAL FILTER
VOLTAGE
CURRENT
TEMPERATURE
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
FUNCTIONAL DESCRIPTION (continued)The bq2084-V140 interfaces with the bq29312 to perform battery protection, cell balancing, and voltagetranslation functions. The bq2084-V140 can accept any NTC thermistor (default is Semitec 103AT) fortemperature measurement or can also be configured to use its internal temperature sensor. The bq2084-V140uses temperature to monitor the battery pack and to compensate the self-discharge estimate.
The bq2084-V140 uses an integrating sigma-delta analog-to-digital converter (ADC) for current measurementand a second sigma-delta ADC for individual cell and battery voltage and temperature measurement. Theindividual cell and pack voltages, Voltage(),Current(),AverageCurrent() and Temperature() are updated every 1s during normal operation.
The integrating ADC measures the charge and discharge flow of the battery by monitoring a small-value senseresistor between the SR1 and SR2 pins. The integrating ADC measures bipolar signals from -0.25 V to 0.25 µV.The bq2084-V140 detects charge activity when VSR = V(SR1)-V(SR2) is positive and discharge activity whenVSR = V(SR1)-V(SR2) is negative. The bq2084-V140 continuously integrates the signal over time, using aninternal counter. The fundamental rate of the counter is 0.65 nVh. The bq2084-V140 updatesRemainingCapacity() with the charge or discharge accumulated in this internal counter once every second.
The bq2084-V140 provides an auto-calibration feature to cancel the voltage offset error across SR1 and SR2 formaximum charge measurement accuracy. The bq2084-V140 performs auto-calibration when the SMBus linesstay low for a minimum of 20 s when it internally connects SR1 to SR2 and measures the internal offset. Withthis feature the bq2084-V140 is capable of automatic offset calibration down to <1 µV.
The bq2084-V140 does not measure charge or discharge counts below the digital filter threshold. The digitalfilter threshold is programmed in the Digital Filter DF 0x2c and should be set sufficiently high to prevent falsesignal detection with no charge or discharge flowing through the sense resistor.
While monitoring SR1 and SR2 for charge and discharge currents, the bq2084-V140 monitors the individualseries cell voltages through the bq29312. The bq2084-V140 configures the bq29312 to present the selected cellto the CELL pin of the bq29312, which should be connected to VIN of the bq2084-V140. The internal ADC of thebq2084-V140 then measures the voltage and scales it appropriately. The bq2084-V140 then reports theVoltage() and the individual cell voltages in VCELL1(),VCELL2(),VCELL3(), and VCELL4(). An additionalSMBus command (0x45) returns the measured ADC Reading of the PACK input to the AFE.
The bq2084-V140 uses the SR1 and SR2 inputs to measure and calculate the battery charge and dischargecurrent. This value is reported via the SBS command Current().AverageCurrent() is implemented as asingle-pole IIR filter with a 14.5-s time constant.
The TS input of the bq2084-V140 along with an NTC thermistor measures the battery temperature as shown inthe schematic. The bq2084-V140 reports temperature via the SBS command Temperature().
The bq2084-V140 can also be configured to use its internal temperature sensor by setting the IT bit in MiscConfiguration DF 0x2a-0x2b. Data flash locations DF 0xb5 through DF 0xc0 also have to be changed toprescribed values if the internal temperature sensor option is selected.
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GAS GAUGE OPERATION
General
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
FUNCTIONAL DESCRIPTION (continued)Table 1. Data Flash Settings for Internal or External Temperature Sensor
INTERNAL TEMP EXTERNAL TEMP SENSOR SETTINGLOCATION
SENSOR SETTING (Semitec 103AT)LABEL
Dec (Hex) Dec (Hex) Dec (Hex)
Misc. Config 42 (0x2a) Bit 7 = 1 Bit 7 = 0TS Const1 A3 164/5 (0xb5/6) 0 (0x0000) –28285 (0x9183)TS Const2 A2 166/7 (0xb7/8) 0 (0x0000) 20848 (0x5170)TS Const3 A1 168/9 (0xb9/a) –11136 (0xd480) –7537 (0xe28f)TS Const4 A0 170/1 (0xbb/c) 5734 (0x1666) 4012 (0x0fac)Min Temp AD 172/3 (0xbd/e) 0 (0x0000) 0 (0x000)Max Temp 174/5 (0xbf/c0) 5734 (0x1666) 4012 (0x0fac)
The operational overview in Figure 1 illustrates the gas gauge operation of the bq2084-V140. Table 3 describesthe bq2084-V140 registers.
Figure 1. bq2084-V140 Gas Gauging Operational Overview
The bq2084-V140 accumulates a measure of charge and discharge currents and estimates self-discharge of thebattery. The bq2084-V140 compensates the charge current measurement for temperature and state-of-charge ofthe battery. The bq2084-V140 also adjusts the self-discharge estimation based on temperature.
The main charge counter RemainingCapacity() (RM) represents the available capacity or energy in the battery atany given time. The bq2084-V140 adjusts RM for charge, self-discharge, and other compensation factors. Theinformation in the RM register is accessible through the SMBus interface and is also represented through theLED display.
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Main Gas-Gauge Registers
Capacity Learning (FCC Update) and Qualified Discharge
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The FullChargeCapacity() (FCC) register represents the last measured learned full discharge of the battery. It isused as the battery full-charge reference for relative capacity indication. The bq2084-V140 updates FCC afterthe battery undergoes a qualified discharge from nearly full to a low battery level. FCC is accessible through theSMBus interface.
The Discharge Count Register (DCR) is a non-accessible register that tracks discharge of the battery. Thebq2084-V140 uses the DCR register to update the FCC register if the battery undergoes a qualified dischargefrom nearly full to a low battery level. In this way, the bq2084-V140 learns the true discharge capacity of thebattery under system-use conditions.
RemainingCapacity() (RM)
RM represents the remaining capacity in the battery. The bq2084-V140 computes RM in units of either mAh or10 mWh depending on the selected mode. See Battery Mode() (0x03) for units configuration. RM counts upduring charge to a maximum value of FullChargeCapacity() (FCC) and down during discharge andself-discharge to a minimum of 0. In addition to charge and self-discharge compensation, the bq2084-V140calibrates RM at three low-battery-voltage thresholds, EDV2, EDV1, and EDV0 and three programmablemidrange thresholds VOC25, VOC50, and VOC75. This provides a voltage-based calibration to the RM counter.
DesignCapacity () (DC)
DC is the user-specified battery full capacity. It is calculated from Pack Capacity DF 0x32-0x33 and isrepresented in units of mAh or 10 mWh. It also represents the full-battery reference for the absolute displaymode.
FullChargeCapacity() (FCC)
FCC is the last learned measured discharge capacity of the battery. It is represented in units of either mAh or 10mWh, depending on the selected mode. On initialization, the bq2084-V140 sets FCC to the value stored in FullCharge Capacity DF 0x36-0x37. During subsequent discharges, the bq2084-V140 updates FCC with the lastlearned measured discharge capacity of the battery. The last learned measured discharge of the battery isbased on the value in the Discharge Count Register (DCR) after a qualified discharge occurs. Once updated, thebq2084-V140 writes the new FCC value to data flash in mAh to Full Charge Capacity. FCC represents thefull-battery reference for the relative display mode, relative state of charge and AtRate() calculations.
Discharge Count Register (DCR)
The DCR register counts up during discharge, independent of RM. DCR counts discharge activity, battery loadestimation, and self-discharge increments. The bq2084-V140 initializes DCR, at the beginning of a discharge, toFCC - RM when FCC - RM is within the programmed value in Near Full DF 0x30. The DCR initial value of FCC -RM is reduced by FCC/128 if SC = 1 (bit 5 in Gauge Configuration) and is not reduced if SC = 0. DCR stopscounting when the battery voltage reaches the EDV2 threshold on discharge.
The bq2084-V140 updates FCC with an amount based on the value in DCR if a qualified discharge occurs. Thenew value for FCC equals the DCR value plus the programmable nearly full and low battery levels, according tothe following equation:FCC (new) = DCR (final) = DCR (initial) + Measured Discharge to EDV2 + (FCC x Battery Low%)
here Battery Low % = (value stored in DF 0x2f) ÷2.56
A qualified discharge occurs if the battery discharges from RM = FCC - Near Full to the EDV2 voltage thresholdwith the following conditions:•No more than 256 mAh of self-discharge or battery load estimation occurs during the discharge period.•The temperature does not drop below the low temperature threshold programmed in Learning Low Temp DF0xac during the discharge period.•The battery voltage reaches the EDV2 threshold during the discharge period, and the voltage is greater thanor equal to the EDV2 threshold minus 256 mV when the bq2084-V140 detects EDV2.•No midrange voltage correction occurs during the discharge period.
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End-of-Discharge Thresholds and Capacity Correction
EDV Thresholds and Near-Full Programming
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
•Current remains ≤3C/32 when EDV2 or Battery Low % level is reached.•No overload condition exists when EDV2 threshold is reached, or if RM() has dropped to Battery Low% xFCC,
•No valid charge activity occurs during the discharge period. A valid charge is defined as an uninterruptedcharge of 10 mAh into the battery.
The bq2084-V140 sets VDQ = 1 in PackStatus() when qualified discharge begins. The bq2084-V140 sets VDQ= 0 if any disqualifying condition occurs. FCC cannot be reduced by more than 256 mAh or increased by morethan 512 mAh during any single update cycle. The bq2084-V140 saves the new FCC value to the data flashwithin 4 seconds of being updated.
The bq2084-V140 monitors the battery for three low-voltage thresholds, EDV0, EDV1, and EDV2. The EDVthresholds can be programmed for determination based on the overall pack voltage or an individual cell level.The EDVV bit in Pack Configuration DF 0x28 configures the bq2084-V140 for overall voltage or single-cell EDVthresholds. If programmed for single-cell EDV determination, the bq2084-V140 determines EDV on the basis ofthe lowest single-cell voltage. Fixed EDV thresholds must be programmed in EMF/EDV0 DF 0x95-0x96, EDV C0Factor/EDV1 DF 0x97-0x98, and EDV R Factor/EDV2 DF 0x99-0x9a.
If the CEDV bit in Gauge Configuration DF 0x29 is set, automatic compensated EDVs are enabled and thebq2084-V140 computes the EDV0, EDV1, and EDV2 voltage thresholds based on the values in DF 0x95-0xa0and the battery's current discharge rate and temperature. If FEDV0 in Gauge Configuration is also set thenEDV0 is not compensated. The bq2084-V140 disables EDV detection if Current( ) exceeds the Overload Currentthreshold programmed in DF 0x5b-DF 0x5c. The bq2084-V140 resumes EDV threshold detection after Current( )drops below the Overload Current threshold. Any EDV threshold detected is reset after charge is detected andVDQ is cleared after 10 mAh of charge.
The bq2084-V140 uses the EDV thresholds to apply voltage-based corrections to the RM register according toTable 2 .
Table 2. State-of-Charge Based on Low Battery Voltage
THRESHOLD RELATIVE STATE OF CHARGE
EDV0 0%EDV1 3%EDV2 Battery Low %
The bq2084-V140 performs EDV-based RM adjustments with Current()≤C/32. No EDV flags are set if current <C/32.
The bq2084-V140 adjusts RM as it detects each threshold. If the voltage threshold is reached before thecorresponding capacity on discharge, the bq2084-V140 reduces RM to the appropriate amount as shown inTable 2 .
If an RM % level is reached on discharge before the voltage reaches the corresponding threshold, then RM isheld at that % level until the threshold is reached. RM is only held if VDQ = 1, indicating a valid learning cycle isin progress. If Battery Low % is set to zero, EDV1 and EDV0 corrections are disabled.
The bq2084-V140 uses the values stored in data flash for the EDV0, EDV1, and EDV2 values or calculates thethree thresholds from a base value and the temperature, capacity, and rate adjustment factors stored in dataflash. If EDV compensation is disabled, then EDV0, EDV1, and EDV2 are stored directly in mV in DF 0x95-0x96,DF 0x97-0x98, and DF 0x99-0x9a, respectively.
For capacity correction at EDV2, Battery Low % DF 0x2f can be set at a desired state-of-charge,STATEOFCHARGE%, in the range of 3-19%. Typical values for STATEOFCHARGE% are 5-7%, representing5-7% capacity.
Battery Low % = ( STATEOFCHARGE% x 2.56)
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EDV Discharge Rate and Temperature Compensation Programming
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The bq2084-V140 updates FCC if a qualified discharge occurs from a near-full threshold of FCC - Near Full,until EDV2 condition is reached. The desired near-full threshold window is programmed in Near Full in DF 0x30,0x31 in mAh.
If EDV compensation is enabled, the bq2084-V140 calculates battery voltage to determine EDV0, EDV1, andEDV2 thresholds as a function of battery capacity, temperature, and discharge load. The general equation forEDV0, EDV1, and EDV2 calculation isEDV0,1,2 = n (EMF ×FBL – | ILOAD | ×R0 ×FTZ)EMF is a no-load cell voltage higher than the highest cell EDV threshold computed. EMF is programmedin mV in EMF/EDV1 DF 0x95-0x96.ILOAD is the current discharge load magnitude.n = the number of series cells
FBL is the factor that adjusts the EDV voltage for battery capacity and temperature to match the no-loadcharacteristics of the battery.FBL = f ( C0, C + C1, T )C (either 0%, 3%, or Battery Low % for EDV0, EDV1, and EDV2, respectively) and C0 are thecapacity-related EDV adjustment factors. C0 is programmed in EDV C0 Factor/EDV1 DF 0x97-98. C1 isthe desired residual battery capacity remaining at EDV0 (RM = 0). The C1 factor is stored in EDV C1Factor DF 0xa0.T is the current temperature in °K.
R0 ×FTZ represents the resistance of a cell as a function of temperature and capacity.FTZ = f ( R1, T0, T, C + C1, TC)R0 is the first order rate dependency factor stored in EDV R0 Factor/EDV2 DF 0x99-0x9a.T is the current temperature; C is the battery capacity relating to EDV0, EDV1, and EDV2.R1 adjusts the variation of impedance with battery capacity. R1 is programmed in EDV R1 Rate FactorDF 0x9d-0x9e.
T0 adjusts the variation of impedance with battery temperature. T0 is programmed in EDV T0 RateFactor DF 0x9b-0x9c.TC adjusts the variation of impedance for cold temperatures (T < 23 °C). TC is programmed in EDV TCDF 0x9f.
Typical values for the EDV compensation factors, based on overall pack voltages for a Li-ion 3s2p 18650 pack,are:
EMF = 11550/3
T0 = 4475C0 = 235C1 = 0R0 = 5350/3
R1 = 250TC = 3
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Table 3. bq2084-V140 Register Functions
FUNCTION COMMAND CODE ACCESS UNITS
ManufacturerAccess 0x00 Read/write NARemainingCapacityAlarm 0x01 Read/write mAh, 10 mWhRemainingTimeAlarm 0x02 Read/write minutesBatteryMode 0x03 Read/write NAAtRate 0x04 Read/write mA, 10 mWAtRateTimeToFull 0x05 Read minutesAtRateTimeToEmpty 0x06 Read minutesAtRateOK 0x07 Read BooleanTemperature 0x08 Read 0.1 °KVoltage 0x09 Read mVCurrent 0x0a Read mAAverageCurrent 0x0b Read mAMaxError 0x0c Read percentRelativeStateOfCharge 0x0d Read percentAbsoluteStateOfCharge 0x0e Read percentRemainingCapacity 0x0f Read mAh, 10 mWhFullChargeCapacity 0x10 Read mAh, 10 mWhRunTimeToEmpty 0x11 Read minutesAverageTimeToEmpty 0x12 Read minutesAverageTimeToFull 0x13 Read minutesChargingCurrent 0x14 Read mAChargingVoltage 0x15 Read mVBattery Status 0x16 Read NACycleCount 0x17 Read cyclesDesignCapacity 0x18 Read mAh, 10 mWhDesignVoltage 0x19 Read mVSpecificationInfo 0x1a Read NAManufactureDate 0x1b Read NASerialNumber 0x1c Read integerReserved 0x1d-0x1f 0 0ManufacturerName 0x20 Read stringDeviceName 0x21 Read stringDeviceChemistry 0x22 Read stringManufacturerData 0x23 Read stringPack status 0x2f (LSB) Read NAPack configuration 0x2f (MSB) Read NAVCELL4 0x3c Read mVVCELL3 0x3d Read mVVCELL2 0x3e Read mVVCELL1 0x3f Read mVVPACK 0x45 Read mVAFEData 0x46 Read hex
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Self-Discharge
Battery Electronic Load Compensation
Midrange Capacity Corrections
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The bq2084-V140 estimates the self-discharge of the battery to maintain an accurate measure of the batterycapacity during periods of inactivity. The bq2084-V140 makes self-discharge adjustments to RM every 1/4 swhen awake and periodically (determined by Sleep Timer DF 0xfe) when in sleep mode. The self-dischargeestimation rate for 25 °C is doubled for each 10 degrees above 25 °C or halved for each 10 degrees below 25 °C.Table 4 shows the relation of the self-discharge estimation at a given temperature to the rate programmed for25 °C (Y% per day programmed in DF 0x2d).
Table 4. Self-Discharge for Rate Programmed
TEMPERATURE ( °C) SELF-DISCHARGE RATE
Temp < 10 1/4 Y% per day10 ≤Temp <20 ½ Y% per day20 ≤Temp <30 Y% per day30 ≤Temp <40 2Y% per day40 ≤Temp <50 4Y% per day50 ≤Temp <60 8Y% per day60 ≤Temp <70 16Y% per day70 ≤Temp 32Y% per day
The nominal self-discharge rate, %PERDAY (% per day), is programmed in an 8-bit value Self-Discharge RateDF 0x2d by the following relation:Self-Discharge Rate = %PERDAY/ 0.01
The bq2084-V140 can be configured to compensate for a constant load (as from battery electronics) present inthe battery pack at all times. The bq2084-V140 applies the compensation continuously when the charge ordischarge is below the digital filter. The bq2084-V140 applies the compensation (BEL) in addition toself-discharge. The compensation occurs at a rate determined by the value stored in Electronics Load DF 0x2e.The compensation range is 0 µA-765 µA in steps of approximately 3 µA .The data is stored as follows:Electronics Load = BEL / 3
The bq2084-V140 applies midrange capacity corrections when the VCOR bit is set in Gauge Configuration DF0x29. The bq2084-V140 adjusts RM to the associated percentage at three different voltage levels: VOC25,VOC50, and VOC75 .The VOC values represent the open-circuit battery voltage at which RM corresponds to theassociated percentage for each threshold.
For the midrange corrections to occur, the temperature must be in the range of 19 °C to 31 °C inclusive andCurrent() and AverageCurrent() must both report between -64 mA and 0. The bq2084-V140 makes midrangecorrections as shown in Table 5 . For a correction to occur, the bq2084-V140 must detect the need for correctiontwice during subsequent 20-s intervals. With the VCOR bit set, the bq2084-V140 makes midrange correctionswhenever conditions permit.
If the OTVC bit in Gauge Configuration DF 0x29 is set and VCOR = 0, the bq2084-V140 makes two Voltage()measurements, determines the average of the two readings and sets the appropriate RM level. No furtherRSOC% vs Voltage() validation is performed until after the next device reset.
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Charge Control
Charging Voltage Broadcasts
Charging Current Broadcasts
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Table 5. Midrange Corrections
CONDITION RESULT
≤VOC75 and RelativeStateOfCharge() ≤63% RelativeStateOfCharge() →75%≤VOC75 and RelativeStateOfCharge() ≤87% RelativeStateOfCharge() →75%≤VOC50 and RelativeStateOfCharge() <38% RelativeStateOfCharge() →50%Voltage()
<VOC50 and RelativeStateOfCharge() ≤62% RelativeStateOfCharge() →50%≤VOC25 and RelativeStateOfCharge() ≤13% RelativeStateOfCharge() →25%< VOC25 and RelativeStateOfCharge() ≤37% RelativeStateOfCharge() →25%
Three voltage-based thresholds, VOC25 DF 0x88-0x89, VOC50 DF 0x83-0x84, and VOC75 DF 0x7e-0x7f, arestored in the data flash in mV.
The bq2084-V140 internal charge control is compatible with the constant current/constant voltage profile forLi-ion. The bq2084-V140 detects primary charge termination on the basis of the tapering charge current duringthe constant-voltage phase.
The bq2084-V140 supports SBS charge control by broadcasting the ChargingCurrent() and ChargingVoltage() tothe Smart Charger address. The bq2084-V140 broadcasts the requests every 10 seconds. The bq2084-V140updates the values used in the charging current and voltage broadcasts based on the battery's state of charge,voltage, and temperature.
The 16-bit value (mV) for charging voltage is programmed in Charging Voltage DF 0x03a-0x3b although it canbe set to 0 in different operating conditions. It also sets the base value for determining overvoltage conditionsduring charging and voltage compliance during a constant-voltage charging methodology.
The 16-bit value, Over Voltage Margin DF 0x5d-0x5e, sets the limit over ChargingVoltage() in mV that is to beconsidered as an overvoltage charge-suspension condition.
ChargingCurrent() values are either broadcast to a Level 2 smart battery charger or read from the bq2084-V140by a Level 3 smart battery charger. The ChargingCurrent() may take any of four different values: Fast-ChargingCurrent DF (0x3e-0x3f), Maintenance Charging Current (DF 0x40-0x41), Precharge Current (0x42-0x43) or 0depending on charge state and operating conditions.
When fast charge is allowed, the bq2084-V140 sets ChargingCurrent() to the rate programmed in Fast-ChargingCurrent DF 0x3e-0x3f. Fast-Charging Current is stored in mA.
When fast charge terminates, the bq2084-V140 sets ChargingCurrent() to zero and then to theMaintenanceCharging Current DF 40 0x41 when the termination condition ceases. The desired maintenancecurrent is stored in mA.
When Voltage() is less than EDV0, the bq2084-V140 sets ChargingCurrent() to Precharge Current DF 0x42,0x43. Typically this rate is larger than the maintenance rate to charge a deeply depleted pack up to the pointwhere it may be fast charged. The desired precharge rate is stored in mA.
If temperature is between the Charge Inhibit Temp Low (DF0x46) and the precharge threshold PC ( °C), thebq2084-V140 sets ChargingCurrent() to Precharge Current. The threshold is programmed in the PrechargeTemp DF 0x44. The maximal value of precharge temperature threshold setting is 12.7 °C.•Precharge Temp = PC ( °C) / 0.1
The bq2084-V140 also sets ChargingCurrent() to the precharge rate if Voltage() is less than the valueprogrammed in Precharge Voltage DF 0x3c-0x3d. Precharge Voltage is programmed in mV.
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Alarm Broadcasts to Smart Charger and Host
Precharge Qualification
Charge Suspension
Pulse Charge
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
If any of the bits 8-15 in BatteryStatus() are set, the bq2084-V140 broadcasts an AlarmWarning() message tothe Host address. If any of the bits 12-15 in BatteryStatus() are set, the bq2084-V140 also sends anAlarmWarning() message to the Smart Charger address. The bq2084-V140 repeats the AlarmWarning()messages every 10 seconds until the alarm bits are cleared. All broadcasts can be disabled by setting SM (bit 2)in Pack Configuration (DF 0x28).
The bq2084-V140 sets ChargingCurrent() to the precharge rate as programmed in Precharge Current DF0x42-0x43 under the following conditions:•Voltage: The bq2084-V140 requests the precharge charge rate when any cell voltage drops below theprecharge threshold or when the EDV0 threshold is detected. Once requested, a precharge rate remainsuntil all cell voltages increase above the precharge threshold and the EDV0 condition does not exist. Theprecharge threshold is programmed in Precharge Voltage DF 0x3c-0x3d.•Temperature: The bq2084-V140 requests the precharge rate when Temperature() is between Charge InhibitTemp Low (DF0x46) and the precharge threshold programmed in Precharge Temp 0x44. Temperature( )must be equal to or greater than the precharge threshold + 3 °C to allow the fast-charge rate.
The bq2084-V140 may temporarily suspend charge if it detects a charging fault. A charging fault includes thefollowing conditions.
•Overcurrent: An overcurrent condition exists when the bq2084-V140 measures the charge current to begreater than Charge OC Threshold (DF 0x12a-0x12b) for a time greater than Charge OC Time (DF 0x12c ).On detecting an overcurrent condition, the bq2084-V140 turns off the Charge FET. If the NonremovableBattery bit is not set in Misc Configuration DF 0x2a, then the Discharge FET is turned off also. This conditionis cleared when the pack is removed or if the Nonremovable Battery bit is set in Misc Configuration DF 0x2aand when a discharge current is detected or when SBS AverageCurrent() is less than the ClearFailCurrentDF 0x61-0x62 for FaultResetTime DF 0x130.•Overtemperature: During charging, an overtemperature condition exists when Temperature() is greater thanthe Charge Suspend Temp High value programmed in DF 0x6d, 0x6e. On detecting an overtemperaturecondition, if enabled by the OT bit in Misc Configuration DF 0x2a, the bq2084-V140 turns off the Charge andDischarge FETs. The overtemperature condition is cleared when Temperature() is equal to or below ChargeSuspend Temp High Reset (DF 0x6f -0x70) .The condition is also cleared if the pack is removed.•Undertemperature: During charging, an undertemperature condition exists when Temperature() is less thanthe Charge Suspend Temp Low in DF 0x79 or Charge Inhibit Temp Low in DF 0x46. On detecting anundertemperature condition the bq2084-V140 turns off the Charge FET. The undertemperature condition iscleared when Temperature() is greater than Charge Suspend Temp Low DF 0x79 .The condition is alsocleared if the pack is removed. The maximal value of Charge Suspend Temp Low setting is 12.7 °C.•Charging exceeds Maximum Charging Time in DF 0x10f-0x110. If charging time reaches Maximum ChargeTime, the Charge FET is turned off. This condition is cleared when the pack detects discharge current or isremoved.
•Cell or Pack Overvoltage: An overvoltage condition exist when any cell is greater than Cell Over VoltageLimit in DF 0x63-0x64 or if Voltage() is greater than Charging Voltage in 0x3a-0x3b plus OvervoltageMarginin 0x5d-05e. This condition is cleared when the pack is removed or if the Nonremovable Battery bit is set inMisc Configuration DF 0x2a and when a discharge current is detected or when SBS AverageCurrent() isless than the ClearFailCurrent DF 0x61-0x62 for FaultResetTime DF 0x130. Also, the overvoltage conditionmust be cleared by Voltage() less than Charging Voltage in 0x3a-0x3b plus OvervoltageMargin in 0x5d-05eand all cell voltages less than Cell Over Voltage Reset in DF 0xe0-0xe1.•Charging is also temporarily suspended during pulse-charging, but this is not considered a fault condition.
The bq2084-V140 is capable of charge control using a pulse-charging algorithm, which allows for charge controlin systems where the charger does not control current.
The pulse-charging algorithm uses voltage thresholds and associated time limits for control. These are stored asconstants in data flash. The cell voltages are read by the a/d converter every 125 ms during charging. The
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Primary Charge Termination
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
voltage used for comparison to the thresholds is the highest cell voltage. These thresholds are set by three dataflash constants: Von Charge Voltage,Voff Charge Voltage, and Vmax Charge Voltage.Von is the lowest ofthese, and is the threshold below which the charge FET is turned on, provided the minimum off time ( PulseMinimum Off Time) has been met. When the voltage crosses the Voff threshold, the maximum on time ( PulseMaximum On Time) begins to count down. When this time has expired, the charge FET is turned off. Any timeVmax is exceeded, the charge FET is turned off immediately.
The rules are:1. If charge FET is on:a. If voltage above Vmax, turn off.b. Else if voltage above Voff and max on time expired, turn off.c. Else count down max on time.2. If charge FET is off:a. If voltage below Von and minimum off time, turn on.b. Else increment off time.
Voltage is sampled every 125 ms; therefore, the minimum off time and maximum on time are in units of 125ms,and pulse on and off times are integral multiples of 125 ms.
The voltage thresholds can be chosen in such a way that they alter the charge mechanism. If Voff is set equal toVmax, then every time this threshold is crossed, the charge FET turns off immediately. This effectively disablesthe maximum charge time, so that the Voff threshold has no effect. In this case, the algorithm can be describedas having two voltage thresholds, rather than three. The charge FET simply turns on and off as it crosses thetwo thresholds.
The minimum off time can be similarly disabled by setting it to zero or one. Due to the sample interval, thecharge FET always is off for at least one 125-ms cycle.
Thresholds must be chosen carefully to get the desired charging behavior. For example, if Von is set belowcharge voltage minus taper voltage, the pack can never detect full charge. During pulse charging, the chargeFET remains off until the cells relax to below the Von voltage, which is below the qualification voltage for fullcharge detection.
During cycle phase of pulse charging (charge FET ON), the voltage can exceed Voff value for a period of 125msuntil next sample is taken and FET is switched OFF. To prevent cell overvoltage termination, or packovervoltage termination during this period, values for cell OV should be set larger than voltage reached duringthis period. Reasonable value of cell OV for given charger current I can be calculated, assuming cell impedanceof 0.08 Ω/cell, as V
(cell)
OV > Von + 0.08 ×I.
Correspondingly, the pack overvoltage margin should be set as V
(margin)
> V
(cell)
OV x n - V
(charge)
where: n = number of series cells.
When charging begins on a depleted battery pack, the voltage is below Voff, and may even stay below Von forsome time. This means the pack is under constant charge, with no pulsing, for some part of the charge cycle. Asthe voltage on the cells rises, it crosses the Voff threshold (or the Vmax threshold if Voff is disabled), and thecharge FET turns off. Initially, the off time is short, because the cells are only barely over the threshold and isquickly relaxed to below Von. As the cell voltages rises, the off times become longer and the on times shorter.This effect, in combination with the reduced current drawn by the cells, results in a gradually declining chargecurrent. Eventually, this current falls below the taper current, and the pack detects the full charge condition andstops charging.
The pulse-charging control operates during normal charging conditions and are overridden in case of a faultcondition. Charging is stopped for any fault conditions which may occur, such as overtemperature orovercurrent, without regard to the voltage thresholds or time limits.
The bq2084-V140 terminates charge if it detects a charge-termination condition based on current taper. Acharge-termination condition includes the following:
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Cell Balancing
DISPLAY PORT
General
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The bq2084-V140 detects a current taper termination when the pack voltage is greater than ChargingVoltage (DF 0x3a-0x3b) minus Current Taper Qualification Voltage (DF 0x4d-0x4e) and theAverageCurrent() is below the Current Taper Threshold (DF 0x4b-0x4c), but greater than the ChargeDetection Current in DF 0x113-0x114, for a period of Current Taper Window (DF 0x4f).Once the bq2084-V140 detects a Primary Charge Termination, the bq2084-V140 sets theTERMINATE_CHARGE_ ALARM and FULLY_CHARGED bits in BatteryStatus(), and turns off the chargeFET via the bq29312. The charge FET is turned on when discharge current is detected and is greater thanDischarge Detection Current (DF 0x115-0x116), to minimize IR losses. The TERMINATE_CHARGE_ALARM is cleared if charge current is no longer detected or the pack is removed, but returns if charging isattempted while the FULLY_CHARGED bit is set.The bq2084-V140 clears the FULLY_CHARGED and TERMINATE_CHARGE_ALARM bit whenRelativeStateOfCharge() is less than the programmed Fully Charged Clear %. See Table 13 for a summaryof BatteryStatus() alarm and status bit operation.
The bq2084-V140 balances the cells during charge by discharging those cells above the threshold set in CellBalance Threshold DF 0xe8-0xe9, if the maximum difference in cell voltages exceeds the value programmed inCell Balance Min DF 0xec. For cell balancing, the bq2084-V140 measures the cell voltages at an interval set inCell Balance Interval DF 0xed. On the basis of the cell voltages, the bq2084-V140 either selects the appropriatecell to discharge or adjusts the cell balance threshold up by the value programmed in Cell Balance Window0xea-0xeb when all cells exceed the cell balance threshold or the highest cell exceeds the cell balance thresholdby the cell balance window.
Cell balancing only occurs when charging current is detected and the cell balance threshold is reset to the valuein Cell Balance Threshold at the start of every charge cycle. The threshold is only adjusted once during anybalance interval.
If the cells are severely imbalanced during charging, where VCELL
(MAX)
- VCELL
(MIN)
>Cell Imbalance ThresholdAND SBS. Current()> Balance IMAX for a period of Cell Imbalance time then the CIM bit in PF Status is set.
Table 6. Cell Balancing and Cell Imbalance Programming
NAME DF ADDRESS DESCRIPTION
Cell Balance Threshold 0xe8-0xe9 Sets the maximum voltage in mV that each cell must achieve to initiate cell balancing.Programming Cell Balance Threshold to 65,535 disables cell balancing.Cell Balance Min 0xec Sets in mV the cell differential that must exist to initiate cell balancingCell Balance Window 0xea-0xeb Sets in mV the amount that the cell balance threshold increases during cell balancingCell Balance Interval 0xed Sets the cell balancing time interval in seconds.Cell Imbalance Threshold 0xee-0xef Sets the severe imbalance fault limit for cell imbalance detectionBalance IMAX 0xf2-0xf3 Sets the charge current required to allow a cell imbalance to be detectedCell Imbalance Time 0x134 Sets the time period during which a cell imbalance must be selected for the bq2084 to enterPF mode.
The display port drives a 3-, 4-, or 5-LED bar-graph display. The display is activated by a logic signal on theDISP input. The bq2084-V140 can display RM in either a relative or absolute mode with each LED representinga percentage of the full-battery reference. In relative mode, the bq2084-V140 uses FCC as the full-batteryreference; in absolute mode, it uses Design Capacity (DC). The DMODE bit in Pack Configuration DF 0x28programs the bq2084-V140 for the absolute or relative display mode. The LED bits program the 3-, 4-, or 5-LEDoption.
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Activation
Display Modes
LI-ION PROTECTION
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The display may be activated at any time by a high-to-low transition on the DISP input. This is usuallyaccomplished with a pullup resistor and a pushbutton switch. Detection of the transition activates the display andstarts a 4-s display timer. Reactivation of the display requires that the DISP input return to a logic-high state andthen transition low again. The second high-to-low transition can be detected only after the display timer expires.If unused, the DISP input must be pulled up to VCC. If the EDV0 bit is set, the bq2084-V140 disables the LEDdisplay.
In relative mode, each LED output represents 20%, 25%, or 33% of the RelativeStateOfCharge() value. Inabsolute mode, each LED output represents 20%, 25% or 33% of the AbsoluteStateOfCharge() value. Table 7shows the display options for 5 LEDs, for 4 LEDs, Table 8 and Table 9 for 3 LEDs. In either mode, thebq2084-V140 blinks the LED display if RemainingCapacity() is less than Remaining CapacityAlarm(). Thedisplay is disabled if EDV0 = 1.
Table 7. Display Mode for Five LEDs
CONDITION
FIVE-LED DISPLAY OPTIONRELATIVE OR ABSOLUTE
StateOfCharge() LED1 LED2 LED3 LED4 LED5
EDV0 = 1 OFF OFF OFF OFF OFF<20% ON OFF OFF OFF OFF≤20%, < 40% ON ON OFF OFF OFF≤40%, < 60% ON ON ON OFF OFF≤60%, < 80% ON ON ON ON OFF≤80% ON ON ON ON ON
Table 8. Display Mode for Four LEDs
CONDITION
FOUR-LED DISPLAY OPTIONRELATIVE OR ABSOLUTE
StateOfCharge() LED1 LED2 LED3 LED4
EDV0 = 1 OFF OFF OFF OFF<25% ON OFF OFF OFF≤25%, < 50% ON ON OFF OFF≤50%, < 75% ON ON ON OFF≤75% ON ON ON ON
Table 9. Display Mode for Three LEDs
CONDITION
THREE-LED DISPLAY OPTIONRELATIVE OR ABSOLUTE
StateOfCharge() LED1 LED2 LED3
EDV0 = 1 OFF OFF OFF<34% ON OFF OFF≤34%, < 67% ON ON OFF≤67% ON ON ON
The bq2084-V140 along with the bq29312 provides protection for Li-ion batteries, as shown in Table 10 . Thebq2084-V140 measures temperature and current and uses the bq29312 to measure individual cell voltage. Thebq2084-V140 uses this information to determine protection requirements and control the safety FETs or SAFEoutput as necessary. It is recommended that the bq2084-V140 protection control be validated by two successivemeasurements by setting VOD=1 in Misc Configuration.
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Protection Configuration
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The bq29312 can independently detect and protect the load from an overload (OL) or short circuit in charge(SCC) or discharge (SCD). The bq29312 sets the appropriate FET state and then alerts the bq2084-V140 withthe XALERT output whenever a protection threshold is breached and its associated delay time has expired. Thebq2084-V140 then determines if and when the FETs should be turned back on.
Table 10. CVOV and CVUV Flags in PackStatus()
FLAG SET CONDITION DSG FET CHG FET CLEAR CONDITION
(1)
Voltage() = ChargingVoltage() + Over
ON OFF
(2)
Voltage() < ChargingVoltage()Voltage MarginCVOV
VCELL
(ANY)
=Cell Over Voltage ON OFF
(2)
VCELL
(ALL)
<Cell Over Voltage ResetCVUV VCELL
(ANY)
=Cell Under Voltage
(3)
ON VCELL
(ALL)
>Cell Under Voltage ResetAverageCurrent() < - Over Load Current OFF
(3)
ON AverageCurrent() < - Current Fault Clear Threshold
(1) Clear is detected and controlled by the bq2084-V140.(2) On if there is a discharge current ≤150 mA(3) On if there is a charge current ≤50 mA
1
st
Level Cell Voltage Thresholds
The cell undervoltage (VUV) and overvoltage (VOV) limits are programmed in Cell Under Voltage and Cell OverVoltage DF 0x65-0x66, DF 0x63-0x64, respectively. Both value sare stored in mV. Cell Over Voltage Reset DF0xe0-0xe1 and Cell Under Voltage Reset 0xe2-0xe3 set the reset points in mV for these safety parameters.
Safety Overvoltage Threshold
The safety voltage threshold is programmed in Safety Over Voltage DF 0x6b-0x6c. It is stored in mV. Exceedingthe Safety Voltage for a period determined by the MISC Config VOD bit causes permanent failure if enabled byPFConfig.
Overcurrent Thresholds
Discharge current threshold is programmed in Discharge OC Threshold DF 0x12d-0x12e. The dischargeovercurrent must exist for time programmed in Discharge OC Time DF 0x12f. When a discharge overcurrentcondition is detected the discharge FET is turned off. Similarly, a charge overcurrent is programmed in ChargeOC ThresholdDF 0x12a-0x12b. The charge overcurrent must exist for the time programmed in Charge OC TimeDF 0x12c or Charge OC Time DF 0x12c. When a charge overcurrent condition is detected, the charge FET isturned off.
Temperature Thresholds
The Safety Over Temperature in Charge (SOTC) threshold is programmed in Safety Over Temperature inCharge DF 0x75-0x76 and Safety Over Temperature in Discharge (SOTD) threshold is programmed in SafetyOver Temperature in Discharge DF 0x77-0x78.
SOTC is stored as Safety Over Temperature in Charge = SOTC/0.1 ( °C) as an unsigned integer
SOTD is stored as Safety Over Temperature in Discharge = SOTD/0.1 ( °C) as an unsigned integer. Exceedingthe Safety Temperatures for a period exceeding Over Temperature Time DF 0x162 causes permanent failure ifenabled by PFConfig.
There are also temperature thresholds to disable both charge and discharge FETs and to set the SBS BatteryStatus Overtemperature bit. The thresholds are set according to whether discharge or charge is detected. TheCharge Suspend Temp High threshold is stored in DF 0x6d-0x6e with the reset threshold stored in DF0x6f-0x70. Likewise, the Over Temperature Discharge threshold is stored in DF 0x71-0x72 with the resetthreshold stored in DF 0x73-0x74. If the OT bit in Misc Configuration is set then all temperature protection isdisabled except for Safety Over Temperature.
The Charge Suspend Temp Low threshold (CSTL) is stored in Charge Suspend Temp Low DF 0x79-0x7a and isstored as Charge Suspend Temp Low = CSTL/0.1 ( °C) as a signed integer. A Charge Suspend Temp Low turnsoff the charge FET. The maximal value of Charge Suspend Temp Low setting is 12.7 °C.
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
AFE Configuration
The AFE protection limits are programmed as specified in the bq29312 data sheet.AFE Over Load DF 0xc5 sets the AFE overload protection threshold.AFE Over Load Delay DF 0xc6 sets the delay timing for overload protection.AFE Short Circuit in Charge DF 0xc7 sets the AFE short circuit in charge protection threshold and delaytime.
AFE Short Circuit in Discharge DF 0xc8 sets the AFE short circuit in discharge protection threshold anddelay time.
SMBus command 0x46 can be used to string-read the AFE RAM with the AFE address 0x00 first, if thebq2084-V140 is not sealed as indicated by bit 5 of PackStatus.
Table 11. Overcurrent Protection
FAILURE FET STATUS CLEAR CONDITIONS
NR=1
AFE OLV CHG on, ZVCHG off, DSG off Same AFE SCDAverage Current ()< Clear Fail Current (DF 0x61/2) forAFE SCC CHG off, ZVCHG off, DSG on Fault Reset Time (DF 0x130), or discharge current >discharge detection current (DF 0x115/6)Average Current () ≤-Clear Fail Current (DF 0x61/2) forAFE SCD CHG on, ZVCHG off, DSG off Fault Reset Time (DF 0x130), or charge current > chargedetection current (DF 0x113/4)GG Charge OC (set by DF 0x12a to 0x12c) CHG off, ZVCHG off, DSG on Same AFE SCCGG Discharge OC (set by DF 0x12d to 0x12f) CHG on, ZVCHG off, DSG off Same AFE SCD
NR=0
FAILURE FET STATUS EXIT CONDITIONS
AFE OLV All FETs off RRES=highAFE SCC All FETs off PRES=highAFE SCD All FETs off PRES=highGG Charge OC (set by DF 0x12a to 0x12c) All FETs off PRES=highGG Discharge OC (set by DF 0x12d to 0x12f) All FETs off PRES=high
The AFE protection features can also recover automatically after AFE Recovery Time (DF 0x160) if the AFERecovery Time is set to a nonzero value. When the protection feature is recovered in this manner, it does notre-trigger for AFE Hold Off Time (DF 0x161).
AFE Integrity Check
The bq2084-V140 checks the programming of the AFE registers at a period determined by AFE Check Time DF0xfb. The units of the check period are seconds unless the bq2084-V140 is in sleep mode, in which case theperiod is AFE Check Time xSleep Current Multiplier (DF 0xfd). If the data is not correct, the bq2084-V140increments an internal counter until it reaches the AFE Fail Limit (DF 0xe4). Setting AFE Check Time to 0disables this function.
When the internal AFE Fail counter reaches AFE Fail Limit, then the AFE bit in PF Status is set.
AFE Watchdog Fault and Clear
The bq29312 has a feature where the 32-kHz output (CLKOUT, pin 35) of the bq2084-V140 is used to drive itsinternal clock. If this clock fails, a fault is declared in the AFE. See the bq29312 data sheet for further details.
The fault is cleared automatically on return of the 32-kHz input via the bq2084-V140 CLKOUT pin.
Permanent Failure Mode ( SAFE Output)
The SAFE output of the bq2084-V140 provides an additional level of safety control. The active low safety outputcan blow a fuse or control another switch on the basis of temperature, pack-voltage cell-voltage, CHG FETFailure, severe cell imbalance, or an integrity check of the AFE and Data Flash configuration registers.
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Permanent Failure Status (PF Status)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The bq2084-V140 can also activate the SAFE output and set the PF Flag based on the PFIN input. If this pin islow for PFIN Time seconds ±1 s, then the PFIN bit in PF Status is set.
The SAFE output can be driven low in any of the following conditions, and the bq2084-V140 sets the PF Flagregister (DF 0x11e) to 0x66 (011001100). The activation of the SAFE output and the setting of the PF Flag canbe enabled or disabled for different safety option per the PF Config (DF 0x11f) register settings.
The SAFE output and PF Flag register can only be cleared using a series of ManufacturerAccess() commands.
Table 12. SAFE Activation Conditions
(1)
CONDITION ACTIONS
Voltage() > Safety Over Voltage (DF 0x6b and 0x6c), SOV and PF setTemperature() > Safety Over Temperature in Charge (DF 0x75 and 0x76) SOTC and PF setTemperature() > Safety Over Temperature in Discharge (DF 0x77 and 0x78) SOTD and PF setWhen Miscellaneous Configuration (0x2a) bit 13 AC is set, and the number of AFE failures has reached the AFE Fail AFE and PF setLimit (DF 0xe4)When VCELL
(MAX)
- VCELL
(MIN)
>Cell Imbalance Threshold (DF 0xee, 0xef) during charging CIM and PF setIf charge FET is off, and charge current greater than FET Fail charge current stored in DF 0x125-0x126 for the time FETF and PF setdetermined by FET Fail time in DF 0x129, or if discharge FET is off and discharge current greater than FET Faildischarge current stored in DF 0x127-0x128 for the time determined by FET Fail time in DF 0x129.The PFIN input has detected a low state for PFIN Time in consecutive seconds, as determined by DF 0x120 PFIN, PF set
(1) SAFE output activated and PF Flag set only if enabled by PF Config (DF 0x0x11f)
PF Status DF 0x11d contains the flags for the cause of the permanent failure mode.b7 b6 b5 b4 b3 b2 b1 b0
PFF PFIN FETF CIM AFE SOTD SOTC SOV
SOV
The SOV bit indicates a safety overvoltage occurred which if enabled by PF Config would cause the SAFEoutput to activate.0 SOV fault not detected (default)1 SOV fault detectedSOTC
The SOTC bit indicates a safety overtemperature in charge occurred which if enabled by PF Config wouldcause the SAFE output to activate.0 SOTC fault not detected (default)1 SOTC fault detectedSOTD
The SOTD bit indicates a safety overtemperature in discharge occurred which if enabled by PF Config wouldcause the SAFE output to activate.0 SOTD fault not detected (default)1 SOTD fault detectedAFE
The AFE bit indicates an AFE integrity fault state occurred which if enabled by PF Config would cause theSAFE output to activate.0 AFE is operating correctly (default)1 AFE Integrity check fail limit reached
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Permanent Failure Configuration (PF Config)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
CIM
The CIM bit indicates that a severe cell imbalance occurred during charging, which if enabled by PF Config,would cause the SAFE output to activate.0 All cells are within the Cell Imbalance Threshold (default)1 There is a severe cell imbalanceFETF
The FETF bit indicates a FET or FET driver failure occurred, which if enabled by PF Config would cause theSAFE output to activate.0 The FETs are operating normally (default)1 The FETs or FET drivers have a faultPFIN
The PFIN bit is used to indicate that the output of the 2
nd
level protector has activated.0 The PFIN input is high (default)1 The PFIN input drive and held low by 2
nd
level protector outputFPP
The FPP bit is used to indicate that current has been detected when the fuse has been set to be blown.0 Current not detected with fuse blown1 Current detected with fuse blown
PF Config DF 0x11f contains the enable/disable configuration that determines if the SAFE output is activatedand the PF Flag set for each possible failure mode.b7 b6 b5 b4 b3 b2 b1 b0
- XPFIN XFETF XCIM XAFE XSOTD XSOTC XSOV
XSOV
The XSOV bit enables or disables the activation of SAFE and the setting of the PF Flag when PF Status SOVis set.
0 Activation disabled (default)1 Activation enabledXSOTC
The XSOTC bit enables or disables the activation of SAFE and the setting of the PF Flag when PF StatusSOTC is set.0 Activation disabled (default)1 Activation enabledXSOTD
The XSOTD bit enables or disables the activation of SAFE and the setting of the PF Flag when PF StatusSOTD is set.0 Activation disabled (default)1 Activation enabledXAFE
The XAFE bit enables or disables the activation of SAFE and the setting of the PF Flag when PF Status AFE isset. Bit 13 of Miscellaneous Config DF 0x2a also needs to be set for activation.
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Permanent Failure Flag (PF Flag)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
0 Activation disabled (default)1 Activation enabledXCIM
The XCIM bit enables or disables the activation of SAFE and the setting of the PF Flag when PF Status CIM isset.
0 Activation disabled (default)1 Activation enabledXFETF
The XFETF bit enables or disables the activation of SAFE and the setting of the PF Flag when PF Status FETFis set.
0 Activation disabled (default)1 Activation enabledXPFIN
The XPFIN bit enables or disables the activation of SAFE and the setting of the PF Flag when PF Status PFINis set.
0 Activation disabled (default)1 Activation enabled
PF Flag DF 0x11e contains the flag indicating if the /SAFE output has been activated.STATE b7 b6 b5 b4 b3 b2 b1 b0
Clear 00000000Set 01100110
PF FLAG
The PF Flag indicates that the SAFE output of the bq2084-V140 has been activated.0x00 SAFE output high (default)0x66 SAFE output activated
An example circuit using the SAFE output to blow a fuse is shown in Figure 2 .
Figure 2. Example SAFE Circuit Implementation
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Low-Power Modes
Shutdown Mode
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The bq2084-V140 enters sleep mode when the charge and discharge current is less than the thresholdprogrammed in Sleep Current Threshold DF 0xfc, the SMBus lines are low for at least 2s, and bit 12 of Misc.Configuration DF 0x2a is set to zero. Additionally, PRES must be pulled high if the NR bit in Misc Config is set to0. The bq2084-V140 wakes up periodically to monitor voltage and temperature and to apply self-dischargeadjustment. The sleep period is set in Sleep Timer DF 0xfe. The bq2084-V140 wakes up at a period set bySleep Current Multiplier DF 0xfd multiplied by Sleep Time to measure current. The bq2084-V140 comes out ofsleep when either of the SMBus lines go high or when the current is measured and it is greater than the SleepCurrent Threshold.
The sleep current threshold, SLP (mA), is stored in Sleep Current Thresh DF 0xfc as:Sleep Current Thresh = SLP(mA)/0.5
The wake-up period for current measurement, WAT(s), is set using the following formula:Sleep Current Multiplier x Sleep Time = WAT(s)
During sleep mode, both charge and discharge FETs are turned off if the NR bit in Misc Config is cleared. If thebq2084-V140 is in Non-Removable mode where NR=1, then the discharge FET retains its state on entry tosleep.
The bq2084-V140 goes into shutdown, in which all FETs are turned off and the pack electronics are powereddown (including the bq2084-V140), when SBS.Voltage() falls below Shutdown Voltage DF 0x7c-0x7d andVoltage at the Pack pin is less than VPACK threshold (DF 0x131, 0x132) both for 2 consecutive samples (1 to 2s).
Vpack is programmed in units of 0.935 mV/count and has tolerance of ±6%. For example, to set 12 V as VpackThreshold, the program value should be 12000/0.935 = 12834.
When the DSG FET is turned on, the pack voltage is close to the battery voltage even with no charger attached.Therefore, to enter shutdown, the Vpack threshold should be set higher than the shutdown threshold plus thetolerance.
The bq2084-V140 can also be instructed to enter Shutdown mode via the ManufacturerAccess() command.When the command is sent to the bq2084-V140, the bq29312 is instructed to enter shutdown mode by thebq2084-V140. This forces the chipset into its lowest power mode. The bq2084-V140 does not issue a shutdowncommand to the AFE unless the pack voltage is less than the Vpack Threshold. Program the Vpack thresholdhigher than the SBS.Voltage() when ship command is issued. Exit from this mode is only achieved byapplication of a charger.
After exiting shutdown mode, the bq2084-V140 does not enter the shutdown mode again until the ShutdownTimer (DF 0x133, units are seconds) has expired even if the correct conditions are present. After the ShutdownTimer has expired, the SMBus command or voltage and current conditions enables the bq2084-V140 to entershutdown mode.
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SBS.VCELLx( ) Measured
SBS.PackVoltage( ) Measured
SBS.Voltage( ) calculated
SBS.Voltage( ) <=
DF.Shutdown
Threshold ?
Yes
No
Normal Operation
SBS.Current( ) <= 0?
No
Yes
Yes
No
bq2084 Enters Shutdown
Has Time since exit
from last Shutdown >
DF.Shutdown Timer?
Yes
No
SBS.PackVoltage( ) <
DF.Vpack Threshold ?
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
DEFAULTS:
Non-Removable PackDF.ShutdownVoltage = 2.8 V x Number of Series cells; DF.ShutdownTimer = 2 sNOTE: VpackThreshold must be greater than Shutdown voltage + 6%.Removable Pack
DF.ShutdownVoltage = 2.8 V x Number of Series cells; DF.ShutdownTimer = 20 sNOTE: VpackThreshold must be greater than Shutdown voltage + 6%.
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Reset Conditions
COMMUNICATION
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Figure 3. Shutdown Flow Chart in Normal Operation
Figure 4. Shutdown Flow Chart in SBS MAC
On power up, the entire IC is reset and data is loaded from Data Flash to configure the SBS Data and thebattery management solution. On a partial reset (loss of VCC but RBI holds RAM valid), a limited number oflocations are taken. These actions are the following:•The AFE registers are rewritten.•PackStatus() EDV2 flag is cleared.•BatteryStatus() DISCHARGING flag is cleared.•The charger and alarm broadcast period is set to 10 seconds between broadcasts.
The bq2084-V140 includes an SMBus communication port. The SMBus interface is a 2-wire bidirectionalprotocol using the SMBC (clock) and SMBD (data) pins. The communication lines are isolated from V
CC
andmay be pulled up higher than VCC. Also, the bq2084-V140 does not pull these lines low if V
CC
to the part iszero. The communication ports allow a host controller, an SMBus compatible device, or other processor toaccess the memory registers of the bq2084-V140. In this way a system can efficiently monitor and manage thebattery.
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SMBus
SMBus Protocol
SMBus Packet Error Checking
PEC Protocol
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The SMBus interface is a command-based protocol. A processor acting as the bus master initiatescommunication to the bq2084-V140 by generating a start condition. A start condition consists of a high-to-lowtransition of the SMBD line while the SMBC is high. The processor then sends the bq2084-V140 device addressof 0001011 (bits 7-1) plus a R/W bit (bit 0) followed by an SMBus command code. The R/W bit (LSB) and thecommand code instruct the bq2084-V140 to either store the forthcoming data to a register specified by theSMBus command code or output the data from the specified register. The processor completes the access witha stop condition. A stop condition consists of a low-to-high transition of the SMBD line while the SMBC is high.With SMBus, the most-significant bit (MSB) of a data byte is transmitted first. In some instances, thebq2084-V140 acts as the bus master. This occurs when the bq2084-V140 broadcasts charging requirementsand alarm conditions to device addresses 0x12 (SBS Smart Charger) and 0x10 (SBS Host Controller.)
The bq2084-V140 supports the following SMBus protocols:•Read word•Write word•Block read
A processor acting as the bus master uses the three protocols to communicate with the bq2084-V140. Thebq2084-V140 acting as the bus master uses the write word protocol.
The SMBD and SMBC pins are open drain and require external pullup resistors. A 1-M Ωpulldown resistor in thebattery pack on SMBC and SMBD is required to ensure the detection of the SMBus off-state, the performance ofautomatic offset calibration, and the initiation of the low-power sleep mode when the battery pack is removed.
The bq2084-V140 supports packet error checking as a mechanism to confirm proper communication between itand another SMBus device. Packet error checking requires that both the transmitter and receiver calculate apacket error code (PEC) for each communication message. The device that supplies the last byte in thecommunication message appends the PEC to the message. The receiver compares the transmitted PEC to itsPEC result to determine if there is a communication error.
The bq2084-V140 can receive or transmit data with or without PEC. Figure 5 shows the communication protocolfor the read word, write word, and read block messages without PEC. Figure 6 includes PEC.
In the read word protocol, the bq2084-V140 receives the PEC after the last byte of data from the host. If the hostdoes not support PEC, the last byte of data is followed by a stop condition. After receipt of the PEC, thebq2084-V140 compares the value to its calculation. If the PEC is correct, the bq2084-V140 responds with anACKNOWLEDGE (ACK). If it is not correct, the bq2084-V140 responds with a NOT ACKNOWLEDGE (NACK)and sets an error code. In the write word and block read, the host generates an ACK after the last byte of datasent by the bq2084-V140. The bq2084-V140 then sends the PEC and the host acting as a master-receivergenerates a NACK and a stop condition.
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Gas Gauge
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Figure 5. SMBus Communication Protocol Without PEC
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Gas Gauge
PEC Calculation
PEC Enable in Master Mode
SMBus On- and Off-State
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Figure 6. SMBus Communication Protocol With PEC
The basis of the PEC calculation is an 8-bit cyclic redundancy check (CRC-8) based on the polynomial C(X) =X8 + X2 + X1 + 1. The PEC calculation includes all bytes in the transmission, including address, command, anddata. The PEC calculation does not include ACKNOWLEDGE, NOT ACKNOWLEDGE, start, stop, and repeatedstart bits.
For example, the host requests RemainingCapacity() from the bq2084-V140. This includes the host following theread word protocol. The bq2084-V140 calculates the PEC based on the following 5 bytes of data, assuming theremaining capacity of the battery is 1001 mAh.•Battery Address with R/W = 0: 0x16•Command Code for RemainingCapacity(): 0x0f•Battery Address with R/W = 1: 0x17•RemainingCapacity(): 0x03e9
For 0x160f17e903, the bq2084-V140 transmits a PEC of 0xe8 to the host.
The PEC for master mode broadcasts to the charger, host, or both can be enabled/disabled with thecombination of the bits HPE and CPE in Pack Configuration DF 0x28.
The bq2084-V140 detects whether the SMBus enters the Off State by monitoring the SMBC and SMBD lines.When both signals are continually low for at least 2.0 s, the bq2084-V140 detects the Off State. When theSMBC and SMBD lines go high, the bq2084-V140 detects the On State and can begin communication within 1ms. One-M Ωpulldown resistors on SMBC and SMBD are recommended for reliable Off State detection.
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Command Codes
Manufacturer Access() (0x00)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The SMBus command codes are in (). Temperature(),Voltage(),Current(), and AverageCurrent(), performancespecifications are at bq29312 regulated VCC (V(REG)) and a temperature of -20 °C to 85 °C.
Description: This function provides writable command codes to control the bq2084-V140 during normaloperation and pack manufacture. Writing the command code to SMB command 0x00 causes the following readswith the SMB command 0x00 to return the word indicated in the table. The following commands are available:COMMAND CODE NAME DESCRIPTION
0x0001 Device Type Returns IC part number so it can be read, i.e., 2084 (0x0824)0x0002 Firmware Rev Returns firmware version so it can be read0x0003 EDV Level Returns the pending end-of-discharge voltage level so it can be read0x0004 Manufacturer Status Returns the battery system status so it can read0x0005 SHIP Command Instructs the bq2084-V140 to instruct the bq29312 to enter ship modeInstructs the bq2084-V140 to restrict access to those functions listed in Table 3 . The0x062b Seal
bq2084-V140 completes the seal function and clears ManufacturerAccess().
The Manufacture Status word is defined as:
b15 b14 b13 b12 b11 b10 b9 b8
FET1 FET0 PF1 PF0 STATE3 STATE2 STATE1 STATE0
b7 b6 b5 b4 b3 b2 b1 b0
00001010
FET1, FET0Indicated the state of the charge and discharge FETs0,0 Both charge and discharge FETs are on.0,1 Charge FET is off, discharge FET is on.1,0 Both charge and discharge FETs are off.1,1 Charge FET is on, discharge FET is off.PF1, PF0Indicates permanent failure cause when permanent failure indicated by STATE3-STATE00,0 Fuse is blown0,1 Cell imbalance failure1,0 Safety voltage failure1,1 FET failureSTATE3, STATE2, STATE1, STATE0Indicates battery state as defined in the State and Status bit Summary.
Purpose: The ManufacturerAccess() function provides the system host access to bq2084-V140 functions thatare not defined by the SBD.
SMBus protocol: Read or write word
Input/Output: Word
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RemainingCapacityAlarm() (0x01)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Table 13. State and Status Bit Summary
CHG ZVCHG PowerState MAC Mode (MSB) CC() CV() DSG FET FUSEFET
(1)
FET Mode
wakeup 0x00 Wake up 0 0 off
(2)
on on
(3)
ok normalprecharge 0x03 Precharge PC CV of
(2)
f on on
(4)
ok normalchargesusp 0x04 Charge Suspension FC CV off on off ok normalterminatecharge 0x07 Charge Terminate MC CV off on off ok normalnormalcharge 0x05 Charge FC
(5)
CV on on off ok normalprovisionalcharge 0 0 off on off ok normal0x01 Normalnormaldischarge FC CV on on off ok normaldepleted PC CV off off off ok normaldepleted_ac PC CV off off off
(
(4)
)
ok normaloverheatdischarge FC CV off off off ok normal0x0e System Presentoverheatcharge FC CV off off off ok normalbattfail_overcharge 0 0 off on off ok normalbattfail_lowtemp 0 0 off on off ok normalbattfail_chargeterminate 0x08 Fault Charge Terminate 0 0 off on off ok normalbattfail_afe_chg 0 0 off of
(6)
f off ok normal0x0c Battery Failurebattfail_afe_dsg FC CV off
(6)
off off ok normalbattfail_chg 0 0 off off
(6)
off ok normal0x0a Over Currentbattfail_dsg FC CV off
(6)
off off ok normalremoved 0x0f Battery Out FC CV off off off ok normalsleep 0x0d Sleep 0 0 off off
(7)
off ok lowpermanent_failure 0x09 Permanent Failure 0 0 off off off blow low
(1) CHG FET always on if discharge current greater than Discharge Detection Current (DF 0x115, 0x116)(2) On if FET Config = 01 (Common precharge, charge FET)(3) ZVCHG FET on, OD FET off if FET Config = 00 or 02 (ZVCHG FET or precharge FET)(4) ZVCHG FET on, OD FET off if FET Config = 00 (ZVCHG FET), or ZVCHG FET off, OD FET on if FET Config = 02 (precharge FET)(5) 0 if CVOV or PC is not CVOV and minimum cell voltage is less than the precharge cell voltage threshold(6) If MiscConfig.Nonremoveable Battery is set, then FET is on.
Description: Sets or gets the low-capacity threshold value. Whenever the RemainingCapacity() falls below thelow-capacity value, the bq2084-V140 sends AlarmWarning() messages to the SMBus host with theREMAINING_CAPACITY_ALARM bit set. A low-capacity value of 0 disables this alarm. The bq2084-V140initially sets the low-capacity value to Remaining Capacity Alarm value programmed in DF 0x02-0x03. Thelow-capacity value remains unchanged until altered by the RemainingCapacityAlarm() function. The low-capacityvalue may be expressed in either current (mA) or power (10 mWh) depending on the setting of theBatteryMode() CAPACITY_MODE bit.
Purpose: The RemainingCapacityAlarm() function can be used by systems that know how much power theyrequire to save their operating state. It enables those systems to more finely control the point at which theytransition into suspend or hibernate state. The low-capacity value can be read to verify the value in use by thebq2084-V140 low-capacity alarm.
SMBus protocol: Read or write word
Input/Output: Unsigned integer-value below which Low Capacity messages are sent.BATTERY MODES
CAPACITY_MODE CAPACITY_MODEBIT = 0 BIT = 1
Units mAh at C/5 10 mWh at P/5Range 0-65,535 mAh 0-65,535 10 mWhGranularity Not applicableAccuracy See RemainingCapacity()
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RemainingTimeAlarm() (0x02)
BatteryMode() (0x03)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Description: Sets or gets the Remaining Time Alarm value. Whenever the AverageTimeToEmpty() falls belowthe remaining time value, the bq2084-V140 sends AlarmWarning() messages to the SMBus host with theREMAINING_TIME_ALARM bit set. A remaining time value of 0 effectively disables this alarm. Thebq2084-V140 initially sets the remaining time value to the Remaining Time Alarm value programmed in DF0x00-0x01. The remaining time value remains unchanged until altered by the RemainingTimeAlarm() function.
Purpose: The RemainingTimeAlarm() function can be used by systems that want to adjust when the remainingtime alarm warning is sent. The remaining time value can be read to verify the value in use by the bq2084-V140RemainingTimeAlarm().
SMBus protocol: Read or write word
Input/Output: Unsigned integer—the point below which remaining time messages are sent.
Units: Minutes
Range: 0 to 65,535 minutes
Granularity: Not applicable
Accuracy: See AverageTimeToEmpty().
Description: Selects the various battery operational modes and reports the battery's mode and requests.
Defined modes include•Whether the battery capacity information is specified in units of mAh or 10 mWh (CAPACITY_MODE bit)•Whether the ChargingCurrent() and ChargingVoltage() values are broadcast to the smart battery chargerwhen the CHARGER_MODE bit is set.•Whether all broadcasts to the smart battery charger and host are disabled
The defined request condition is the battery requesting a conditioning cycle ( RELEARN_FLAG).
Purpose: The CAPACITY_MODE bit allows power management systems to best match their electricalcharacteristics with those reported by the battery. For example, a switching power supply represents a constantpower load, whereas a linear supply is better represented by a constant current model. The CHARGER_MODEbit allows a SMBus host or smart battery charger to override the smart battery desired charging parameters bydisabling the bq2084-V140 broadcasts. The RELEARN_FLAG bit allows the bq2084-V140 to request aconditioning cycle.
SMBus protocol: Read or write word
Input/Output: Unsigned integer—bit mapped—see Table 14 .
Units: Not applicable
Range: 0-1
Granularity: Not applicable
Accuracy: Not applicable
The BatteryMode() word is divided into two halves, the MSB (bits 8-15) which is read/write and the LSB (bits0-7) which is read only. The bq2084-V140 forces bits 0-6 to zero and prohibits writes to bit 7.
Table 14 summarizes the meanings of the individual bits in the BatteryMode() word. Specified default values,where applicable, are noted. INTERNAL_CHARGE_CONTROLLER bit is not used by the bq2084-V140.
PRIMARY_BATTERY_SUPPORT bit is not used by the bq2084-V140.
RELEARN_FLAG bit set indicates that the bq2084-V140 is requesting a capacity relearn cycle for the battery.The bq2084-V140 sets the RELEARN_FLAG on a full reset and if it detects 20-cycle counts without an FCCupdate. The bq2084-V140 clears this flag after a learning cycle has been completed.
CHARGE_CONTROLLER_ENABLED bit is not used by the bq2084-V140. The bq2084-V140 forces this bit tozero.
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
PRIMARY_BATTERY bit is not used by the bq2084-V140. The bq2084-V140 forces this bit to zero.
Table 14. Battery Mode Bits and Values
Battery Mode() BITS BITS USED FORMAT ALLOWABLE VALUES
INTERNAL_CHARGE_CONTROLLER 0 Read only bit flag 1 - always onePRIMARY_BATTERY_SUPPORT 1 Read only bit flag 0 - always zeroReserved 2-6 0 - always zeroRELEARN_FLAG 7 Read only bit flag 0—Battery OK1—Relearn cycle requestedCHARGE_CONTROLLER_ENABLED 8 R/W bit flag Not usedPRIMARY_BATTERY 9 R/W bit flag Not usedReserved 10-12 0 - always zero0—Enable alarm broadcast (default)1—DisableALARM_MODE 13 R/W bit flag
alarm broadcast
0—Enable charging broadcastCHARGER_MODE 14 R/W bit flag
(default)1—Disable charging broadcast0—Report in mA or mAh (default)1—Report inCAPACITY_MODE 15 R/W bit flag
10 mW or 10 mWh
ALARM_MODE bit is set to disable the bq2084-V140s ability to master the SMBus and send AlarmWarning()messages to the SMBus host and the smart battery charger. When set, the bq2084-V140 does not master theSMBus, and AlarmWarning() messages are not sent to the SMBus host and the smart battery charger for aperiod of no more than 60s and no less than 59s. When cleared (default), the smart battery sends theAlarmWarning() messages to the SMBus host and the smart battery charger any time an alarm condition isdetected.
•The ALARM broadcast does not occur more often than once every 10 s. Whenever the BATTERY_MODEcommand is received, the bq2084-V140 resets the bit and starts or restarts a 60-s (nominal) timer. After thetimer expires, the bq2084-V140 automatically enables alarm broadcasts to ensure that the accidentaldeactivation of broadcasts does not persist. An SMBus host that does not want the bq2084-V140 to be amaster on the SMBus must therefore continually set this bit at least once per 59 s to keep the bq2084-V140from broadcasting alarms.•The ALARM_MODE bit defaults to a cleared state when the bq2084-V140 enters SLEEP mode.•The condition of the ALARM-MODE bit does not affect the operation or state of the CHARGER_MODE bit,which is used to prevent broadcasts of ChargingCurrent() and ChargingVoltage() to the smart batterycharger. CHARGER_MODE bit enables or disables the bq2084-V140's transmission of ChargingCurrent()and ChargingVoltage() messages to the smart battery charger. When set, the bq2084-V140 does nottransmit ChargingCurrent() and ChargingVoltage() values to the smart battery charger. When cleared, thebq2084-V140 transmits the ChargingCurrent() and ChargingVoltage() values to the smart battery charger.The CHARGER_MODE bit defaults to a cleared state when the bq2084-V140 enters SLEEP mode.
CAPACITY_MODE bit indicates if capacity information is reported in mA/mAh or 10 mW/10 mWh. When set, thebq2084-V140 reports capacity information in 10 mW/10 mWh as appropriate. When cleared, the bq2084-V140reports capacity information in mA/mAh as appropriate. The CAPACITY_MODE bit defaults to a cleared statewhen the bq2084-V140 enters SLEEP mode.
The following functions are changed to accept or return values in mA/mAh or 10 mW/10 mWh depending on theCAPACITY_MODE bit:•RemainingCapacityAlarm()
•AtRate()
•RemainingCapacity()
•FullChargeCapacity()
•DesignCapacity()
The following functions are calculated on the basis of capacity and may be calculated differently depending onthe CAPACITY_MODE bit:•AtRateOK()
•AtRateTimeToEmpty()
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AtRate() (0x04)
AtRateTimeToFull() (0x05)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
•AtRateTimeToFull()
•RunTimeToEmpty()
•AverageTimeToEmpty()
•AverageTimeToFull()
•Remaining Time Alarm()•BatteryStatus()
The bq2084-V140 updates the non-AtRate related register values immediately after changing the state of theCAPACITY_MODE bit. The AtRate() values are updated after the next AtRate() value is written to thebq2084-V140 (or after the next 1-s scheduled refresh calculation).
Description: The AtRate() function is the first half of a two-function call-set used to set the AtRate value used incalculations made by the AtRateTimeToFull(),AtRateTimeToEmpty(), and AtRateOK() functions. The AtRatevalue may be expressed in either current (mA) or power (10 mW) depending on the setting of the BatteryMode()CAPACITY_MODE bit.
Purpose: Because the AtRate() function is the first half of a two-function call-set, it is followed by the secondfunction of the call-set that calculates and returns a value based on the AtRate value and the battery's presentstate.
•When the AtRate() value is positive, the AtRateTimeToFull() function returns the predicted time to full chargeat the AtRate value of charge.•When the AtRate() value is negative, the AtRateTimeToEmpty() function returns the predicted operating timeat the AtRate value of discharge.•When the AtRate() value is negative, the AtRateOK() function returns a Boolean value that predicts thebattery's ability to supply the AtRate value of additional discharge energy (current or power) for 10 seconds.
The default value for AtRate() is zero.
SMBus protocol: Read or write word
Input/Output: Signed integer-charge or discharge; the AtRate() value is positive for charge, negative fordischarge, and zero for neither (default).
BATTERY MODES
CAPACITY_MODE CAPACITY_MODEBIT = 0 BIT = 1
Units mA 10 mWCharge range 1 to 32,767 mA 1 to 32,767 10 mWDischarge range –1 to –32,768 mA –1 to –32,768 10 mWGranularity 1 UnitAccuracy NA
Description: Returns the predicted remaining time to fully charge the battery at the AtRate() value (mA).
Purpose: The AtRateTimeToFull() function is part of a two-function call-set used to determine the predictedremaining charge time at the AtRate value in mA. The bq2084-V140 updates AtRateTimeToFull() within 5 msafter the SMBus host sets the AtRate value. The bq2084-V140 automatically updates AtRateTimeToFull() basedon the AtRate() value every 1 s.
SMBus protocol: Read word
Output: Unsigned integer—predicted time in minutes to fully charge the battery.
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
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AtRateTimeToEmpty() (0x06)
AtRateOK() (0x07)
Temperature() (0x08)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Accuracy: ±MaxError() * FullChargeCapacity()/|AtRate()|
Invalid Data Indication: 65,535 indicates the AtRate = 0.
Description: Returns the predicted remaining operating time if the battery is discharged at the AtRate() value.
Purpose: The AtRateTimeToEmpty() function is part of a two-function call-set used to determine the remainingoperating time at the AtRate() value. The bq2084-V140 updates AtRateTimeToEmpty() within 5 ms after theSMBus host sets the AtRate() value. The bq2084-V140 automatically updates AtRateTimeToEmpty() based onthe AtRate() value every 1 s.
SMBus protocol: Read word
Output: Unsigned integer—estimated operating time left.
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
Accuracy: -0, +MaxError() ×FullChargeCapacity/|AtRate()|
Invalid Data Indication: 65,535 indicates AtRate = 0.
Description: Returns a Boolean value that indicates whether or not the battery can deliver the AtRate() value ofadditional energy for 10 s. If the AtRate value is zero or positive, the AtRateOK() function ALWAYS returns OK(logic 1).
Purpose: The AtRateOK() function is part of a two-function call-set used by power management systems todetermine if the battery can safely supply enough energy for an additional load. The bq2084-V140 updatesAtRateOK() within 5 ms after the SMBus host sets the AtRate() value. The bq2084-V140 automatically updatesAtRateOK() based on the At Rate() value every 1 second.
SMBus protocol: Read word
Output: Boolean—indicates if the battery can supply the additional energy requested.
Units: Boolean
Range: 1, 0
Granularity: Not applicable
Accuracy: Not applicable
Description: Returns the temperature (K) measured by the bq2084-V140.
Purpose: The Temperature() function provides accurate cell temperatures for use by battery chargers andthermal management systems. A battery charger can use the temperature as a safety check. Thermalmanagement systems may use the temperature because the battery is one of the largest thermal sources in asystem.
SMBus protocol: Read word
Output: Unsigned integer—cell temperature in tenth-degree Kelvin increments.
Units: 0.1 °K
Range: 0 to +6553.5 °K {real range}
Granularity: 0.1 °K
Accuracy: ±1.5 °K (from ideal Semitec 103AT thermistor performance, after calibration)
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Voltage() (0x09)
Current() (0x0a)
AverageCurrent() (0x0b)
MaxError() (0x0c)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Description: Returns the cell-pack voltage (mV).
Purpose: The Voltage() function provides power management systems with an accurate battery terminalvoltage. Power management systems can use this voltage, along with battery current information, tocharacterize devices they control. This ability helps enable intelligent, adaptive power-management systems.
SMBus protocol: Read word
Output: Unsigned integer—battery terminal voltage in mV.
Units: mV
Range: 0 to 20,000 mV
Granularity: 1 mV
Accuracy: ±0.25% (after calibration)
Description: Returns the current being supplied (or accepted) by the battery (mA).
Purpose: The Current() function provides a snapshot for the power management system of the current flowinginto or out of the battery. This information is of particular use in power-management systems because they cancharacterize individual devices and tune their operation to actual system power behavior.
SMBus protocol: Read word
Output: Signed integer—charge/discharge rate in mA increments: positive for charge, negative for discharge.
Units: mA
Range: -32,768 to 32,767 mA
Granularity: 1 mA
Accuracy: 0.25% or 5 mA, whichever is greater
Description: Returns a value that approximates a one-minute rolling average of the current being supplied (oraccepted) through the battery terminals (mA). AverageCurrent() is implemented as a single pole IIR filter with a14.5-s time constant.
Purpose: The AverageCurrent() function provides the average current flowing into or out of the battery for thepower management system.
SMBus protocol: Read word
Output: Signed integer—charge/discharge rate in mA increments: positive for charge, negative for discharge.
Units: mA
Range: -32,768 to 32,767 mA
Granularity: 1 mA
Accuracy: 0.25% or 5 mA, whichever is greater
Description: Returns the expected margin of error (%) in the state of charge calculation. For example, whenMaxError() returns 10% and RelativeStateOfCharge() returns 50%, the RelativeStateOfCharge() is more likelybetween 50% and 60%. The bq2084-V140 sets MaxError() to 100% on a full reset. The bq2084-V140 setsMaxError() to 2% on completion of a learning cycle, unless the bq2084-V140 limits the learning cycle to the+512/-256 mAh maximum adjustment values. If the learning cycle is limited, the bq2084-V140 sets MaxError() to8% unless MaxError() was already below 8%. In this case, MaxError() does not change. The bq2084-V140increments MaxError( ) by 1% after four increments of CycleCount() without a learning cycle. If voltage-basedcorrections are applied to the coulomb counter, MaxError() is set to 25%.
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RelativeStateOfCharge() (0x0d)
AbsoluteStateOfCharge()(0x0e)
RemainingCapacity() (0x0f)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Purpose: The MaxError() function has real value in two ways: first, to give the user a confidence level about thestate of charge and second, to give the power management system information about how aggressive it shouldbe, particularly as the battery nears the end of its life.
SMBus protocol: Read word
Output: Unsigned integer—percent uncertainty for selected information.
Units: %
Range: 2-100%
Granularity: 1%
Accuracy: Not applicable
Description: Returns the predicted remaining battery capacity expressed as a percentage ofFullChargeCapacity() (%).
Purpose: The RelativeStateOfCharge() function is used to estimate the amount of charge remaining in thebattery relative to the last learned capacity.
SMBus protocol: Read word
Output: Unsigned integer-percent of remaining capacity.
Units: %
Range: 0-100%
Granularity: 1%
Accuracy: -0, +MaxError()
Description: Returns the predicted remaining battery capacity expressed as a percentage of DesignCapacity()(%). Note that AbsoluteStateOfCharge() can return values greater than 100%.
Purpose: The AbsoluteStateOfCharge() function is used to estimate the amount of charge remaining in thebattery relative to the nominal or DesignCapacity().
SMBus protocol: Read word
Output: Unsigned integer—percent of remaining capacity.
Units: %
Range: 0-100+%
Granularity: 1%
Accuracy: -0, +MaxError()
Description: Returns the predicted charge or energy remaining in the battery. The RemainingCapacity() value isexpressed in either charge or energy, depending on the setting of the BatteryMode() CAPACITY_MODE bit.
Purpose: The RemainingCapacity() function returns the battery's remaining capacity. This information is anumeric indication of remaining charge or energy given by the AbsoluteStateOfCharge() orRelativeStateOfCharge() functions and may be in a better form for use by power management systems.
SMBus protocol: Read word
Output: Unsigned integer—remaining charge in units of mAh or 10 mWh.
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FullChargeCapacity() (0x10)
RunTimeToEmpty() (0x11)
AverageTimeToEmpty() (0x12)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
BATTERY MODES
CAPACITY_MODE CAPACITY_MODEBIT = 0 BIT = 1
Units mAh 10 mWhRange 0-65,535 mAh 0-65,535 10 mWhGranularity mAh 10 mWhAccuracy -0, +MaxError() * FullCharageCapacity()
Description: Returns the predicted pack capacity when it is fully charged. The FullChargeCapacity() value isexpressed in either current (mAh at a C/5 discharge rate) or power (10 mWh at a P/5 discharge rate) dependingon the setting of the BatteryMode()CAPACITY_MODE bit.
Purpose: The FullChargeCapacity() function provides a means of understanding the tank size of the battery.This information, along with information about the original capacity of the battery, indicates battery wear.
SMBus protocol: Read word
Output: Unsigned integer—estimated full-charge capacity in units of mAh or 10 mWh.BATTERY MODES
CAPACITY_MODE CAPACITY_MODEBIT = 0 BIT = 1
Units mAh 10 mWhRange 0-65,535 mAh 0-65,535 10 mWhGranularity mAh 10 mWhAccuracy -0, +MaxError() ×FullCharageCapacity()
Description: Returns the predicted remaining battery life at the present rate of discharge (minutes).The RunTimeToEmpty() value is calculated based on either current or power depending on the setting of theBatteryMode() CAPACITY_MODE bit.
Purpose: The RunTimeToEmpty() provides the power management system with information about the relativegain or loss in remaining battery life in response to a change in power policy. This information is not the sameas the AverageTimeToEmpty(), which is not suitable to determine the effects that result from a change in powerpolicy.
SMBus protocol: Read word
Output: Unsigned integer—minutes of operation left.
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
Accuracy: -0, + MaxError()×FullChargeCapacity() /Current()
Invalid Data Indication: 65,535 indicates battery is not being discharged.
Description: Returns a predicted remaining battery life (minutes), based on AverageCurrent. TheAverageTimeToEmpty() value is calculated based on either current or power depending on the setting of theBatteryMode()CAPACITY_MODE bit.
Purpose: The AverageTimeToEmpty() displays state-of-charge information in a more useful way. It averagesthe instantaneous estimations so that the remaining time does not appear to jump around.
SMBus protocol: Read word
Output: Unsigned integer—minutes of operation left.
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AverageTimeToFull() (0x13)
ChargingCurrent() (0x14)
ChargingVoltage() (0x15)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
Accuracy: -0, + MaxError() *FullChargeCapacity() /AverageCurrent()
Invalid Data Indication: 65,535 indicates battery is not being discharged.
Description: Returns a predicted remaining time until the battery reaches full charge (minutes), based onAverageCurrent.
Purpose: The AverageTimeToFull() function can be used by the SMBus host's power management system toaid in its policy. It may also be used to find out how long the system must be left on to achieve full charge.
SMBus protocol: Read word
Output: Unsigned integer—remaining time in minutes.
Units: Minutes
Range: 0 to 65,534 minutes
Granularity: 2 minutes or better
Accuracy: -0, + MaxError() *FullChargeCapacity() /AverageCurrent()
Invalid Data Indication: 65,535 indicates the battery is not being charged.
Description: Returns the desired charging rate in mA.
Purpose: The ChargingCurrent() function sets the maximum charge current of the battery.TheChargingCurrent() value should be used in combination with the ChargingVoltage() value to set the charger'soperating point. Together, these functions permit the bq2084-V140 to dynamically control the charging profile(current/voltage) of the battery. The bq2084-V140 can effectively turn off a charger by returning a value of 0 forthis function. The charger may be operated as a constant-voltage source above its maximum regulated currentrange by returning a ChargingCurrent() value of 65,535.
SMBus protocol: Read word
Output: Unsigned integer—maximum charger output current in mA.
Units: mA
Range: 0 to 65,535 mA
Granularity: 1 mA
Accuracy: Not applicable
Invalid Data Indication: 65,535 indicates that a charger should operate as a voltage source outside itsmaximum regulated current range.
Description: Returns the desired charging voltage in mV.
Purpose: The ChargingVoltage() function sets the maximum charge voltage of the battery. TheChargingVoltage() value should be used in combination with the ChargingCurrent() value to set the charger'soperating point. Together, these functions permit the bq2084-V140 to dynamically control the charging profile(current/voltage) of the battery. The charger may be operated as a constant-current source above its maximumregulated voltage range by returning a ChargingVoltage() value of 65,535.
SMBus protocol: Read word
Output: Unsigned integer—charger output voltage in mV.
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BatteryStatus() (0x16)
ALARM BITS
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Units: mV
Range: 0 to 65,535 mV
Granularity: 1 mV
Accuracy: Not applicable
Invalid Data Indication: 65,535 indicates the charger should operate as a current source outside its maximumregulated voltage range.
Description: Returns the bq2084-V140 status word (flags). Some of the BatteryStatus() flags ( andREMAINING_TIME_ALARM) are calculated on the basis of either current or power depending on the setting ofthe BatteryMode()CAPACITY_MODE bit. This is important because use of the wrong calculation mode mayresult in an inaccurate alarm.
Purpose: The BatteryStatus() function is used by the power management system to get alarm and status bits,as well as error codes from the bq2084-V140. This is basically the same information broadcast to both theSMBus host and the smart battery charger by the AlarmWarning() function except that the AlarmWarning()function sets the error code bits all high before sending the data.
SMBus protocol: Read word
Output: Unsigned Integer-status register with alarm conditions bit-mapped as follows:ALARM BITS
0x8000 OVER_CHARGED_ALARM
0x4000 TERMINATE_CHARGE_ALARM
0x2000 Reserved0x1000 OVER_TEMP_ALARM
0x0800 TERMINATE_DISCHARGE_ALARM
0x0400 Reserved0x0200 REMAINING_CAPACITY_ALARM
0x0100 REMAINING_TIME_ALARM
STATUS BITS
0x0080 Initialized0x0040 DISCHARGING0x0020 FULLY_CHARGED
0x0010 FULLY_DISCHARGED
ERROR CODES
0x0007 Unknown Error0x0006 BadSize0x0005 Overflow/Underflow
0x0004 AccessDenied0x0003 UnsupportedCommand
0x0002 ReservedCommand
0x0001 Busy0x0000 OK
OVER_CHARGED_ALARM bit is set whenever the bq2084-V140 detects that the battery is being chargedbeyond the maximum overcharge limit, which is full capacity plus Maximum Overcharge DF 0x51-0x52. This bitis cleared when the bq2084-V140 detects that the battery is no longer being charged and there are 2 mAh ofcontinuous discharge (i.e., the bq2084-V140 detects discharge activity or no activity above the digital filter).
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STATUS BITS
ERROR CODES
CycleCount()(0x17)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
TERMINATE_CHARGE_ALARM bit is set when the bq2084-V140 detects a primary charge termination. This bitis cleared when the bq2084-V140 detects that the battery is no longer being charged.
OVER_TEMP_ALARM bit is set when the bq2084-V140 detects that the internal battery temperature is greaterthan or equal to the OverTemperature Charge threshold while charging or OverTemperature Dischargethreshold while discharging. This bit is cleared when the internal temperature falls back below theOverTemperature Charge Reset or OverTemperature Discharge Reset as appropriate.
TERMINATE_DISCHARGE_ALARM bit is set when RM = 0, Voltage() = Terminate Voltage DF 0x67-0x68, thebattery temperature is less than or equal to the Charge Suspend Temp Low DF 0x79 or the CVUV bit in packstatus is set indicating that a Li-ion cell voltage has dropped below the limit programmed in Cell Under. The bit iscleared when Voltage() > Terminate Voltage,RM() > 0, and the CVUV bit is cleared.
REMAINING_CAPACITY_ALARM bit is set when the bq2084-V140 detects that RemainingCapacity() is lessthan that set by the RemainingCapacityAlarm() function. This bit is cleared when either the value set by theRemainingCapacityAlarm() function is lower than the RemainingCapacity() or when the RemainingCapacity() isincreased by charging.
REMAINING_TIME_ALARM bit is set when the bq2084-V140 detects that the estimated remaining time at thepresent discharge rate is less than that set by the RemainingTimeAlarm() function. This bit is cleared wheneither the value set by the RemainingTimeAlarm() function is lower than the AverageTimeToEmpty() or when theAverageTimeToEmpty() is increased by charging.
The initialized bit is set when the bq2084-V140 has detected a valid load of data flash at full or partial reset. It iscleared when the bq2084-V140 detects an improper data flash load.
DISCHARGING bit is set when the bq2084-V140 determines that the battery is not being charged. This bit iscleared when the bq2084-V140 detects that the battery is being charged.
FULLY_CHARGED bit is set when the bq2084-V140 detects a primary charge termination or an Overchargecondition. It is cleared when RelativeStateOfCharge() is less than the programmed Fully Charged Clear % in DF0x4a.
FULLY_DISCHARGED bit is set when Voltage() or VCELL is less than the EDV2 threshold and Current() <Overload Current or when RelativeStateOfCharge() <Battery Low %. This bit is cleared whenRelativeStateOfCharge() is greater than or equal to 20%.
ERROR CODES DESCRIPTION
OK The bq2084-V140 processed the function code without detecting any errors.Busy The bq2084-V140 is unable to process the function code at this time.Reserved The bq2084-V140 detected an attempt to read or write to a function code reserved by this version of thespecification.
The bq2084-V140 detected an attempt to access an unsupported optional manufacturer function code.Unsupported The bq2084-V140 does not support this function code which is defined in this version of the specification.AccessDenied The bq2084-V140 detected an attempt to write to a read-only function code.Overflow/Underflow The bq2084-V140 detected a data overflow or underflow.BadSize The bq2084-V140 detected an attempt to write to a function code with an incorrect data block.UnknownError The bq2084-V140 detected an unidentifiable error.
Description: Returns the number of cycles the battery has experienced. The mAh value of each count isdetermined by programming the Cycle Count Threshold value in DF 0x38-0x39. The bq2084-V140 saves thecycle count value to Cycle Count DF 0x0c-0x0d after an update to CycleCount().
Purpose: The CycleCount() function provides a means to determine the battery wear. It may be used to giveadvance warning that the battery is nearing its end of life.
SMBus protocol: Read word
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DesignCapacity() (0x18)
DesignVoltage() (0x19)
SpecificationInfo() (0x1a)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Output: Unsigned integer—count of total charge removed from the battery over its life.
Units: cycle
Range: 0 to 65,534 cycles; 65,535 indicates battery has experienced 65,535 or more cycles.
Granularity: 1 cycle
Accuracy: Absolute count
Description: Returns the theoretical or nominal capacity of a new pack. The DesignCapacity() value isexpressed in either current (mAh at a C/5 discharge rate) or power, (10 mWh at a P/5 discharge rate) dependingon the setting of the BatteryMode()CAPACITY_MODE bit.
Purpose: The DesignCapacity() function is used by the SMBus host's power management along withFullChargeCapacity() to determine battery wear. The power management system may present this information tothe user and also adjust its power policy as a result.
SMBus protocol: Read word
Output: Unsigned integer—battery capacity in units of mAh or 10 mWh.BATTERY MODES
CAPACITY_MODE CAPACITY_MODEBIT = 0 BIT = 1
Units mAh 10 mWhRange 0-65,535 mAh 0-65,535 10 mWhGranularity Not applicable Not applicableAccuracy Not applicable Not applicable
Description: Returns the theoretical voltage of a new pack (mV). The bq2084-V140 sets DesignVoltage() to thevalue programmed in Design Voltage DF 0x04-0x05.
Purpose: The DesignVoltage() function can be used to give additional information about a particular smartbattery expected terminal voltage.
SMBus protocol: Read word
Output: Unsigned integer—the battery's designed terminal voltage in mV
Units: mV
Range: 0 to 65,535 mV
Granularity: Not applicable
Accuracy: Not applicable
Description: Returns the version number of the smart battery specification the battery pack supports, as well asvoltage and current scaling information in a packed unsigned integer. Power scaling is the product of the voltagescaling times the current scaling. The SpecificationInfo() is packed in the following fashion:(SpecID_H ×0x10 + SpecID_L) + (VScale + IPScale ×0x10) ×0x100.
The bq2084-V140 VScale (voltage scaling) and IPScale (current scaling) should always be set to zero. Thebq2084-V140 sets SpecificationInfo() to the value programmed in Specification Information DF 0x06-0x07.
Purpose: The SpecificationInfo() function is used by the SMBus host's power management system to determinewhat information the smart battery can provide.
SMBus protocol: Read word
Output: Unsigned integer—packed specification number and scaling information:
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ManufactureDate() (0x1b)
SerialNumber() (0x1c)
ManufacturerName() (0x20)
DeviceName() (0x21)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
FIELD BITS USED FORMAT ALLOWABLE VALUES
SpecID_L 0...3 4-bit binary value 0–15SpecID_H 4...7 4-bit binary value 0–15VScale 8...11 4-bit binary value 0 (multiplies voltage by 10^ VScale)IPScale 12...15 4-bit binary value 0 (multiplies current by 10 ^ IPScale)
Description: This function returns the date the cell pack was manufactured in a packed integer. The date ispacked in the following fashion: (year-1980) * 512 + month * 32 + day. The bq2084-V140 setsManufactureDate() to the value programmed in Manufacture Date DF 0x08-0x09.
Purpose: The ManufactureDate() provides the system with information that can be used to uniquely identify aparticular battery pack when used along with SerialNumber().
SMBus protocol: Read word
Output: Unsigned integer-packed date of manufacture:FIELD BITS USED FORMAT ALLOWABLE VALUES
Day 0...4 5-bit binary value 0-31 (corresponds to date)Month 5...8 4-bit binary value 1-12 (corresponds to month number)Year 9...15 7-bit binary value 0-127 (corresponds to year biased by 1980)
Description: This function is used to return a serial number. This number, when combined with theManufacturerName(), the DeviceName(), and the ManufactureDate(), uniquely identifies the battery (unsignedinteger). The bq2084-V140 sets SerialNumber() to the value programmed in Serial Number DF 0x0a-0x0b.
Purpose: The SerialNumber() function can be used to identify a particular battery. This may be important insystems that are powered by multiple batteries where the system can log information about each battery that itencounters.
SMBus protocol: Read word
Output: Unsigned integer
Description: This function returns a character array containing the battery manufacturer's name. For example,MyBattCo identifies the smart battery manufacturer as MyBattCo. The bq2084-V140 sets ManufacturerName() tothe value programmed in Manufacturer Name DF 0x0e-0x19. When Misc Configuration 2 SSTRING is set thenthe extended manufacturer name data flash is appended (0x151-0x15f).
Purpose: The ManufacturerName() function returns the name of the smart battery manufacturer. Themanufacturer's name can be displayed by the SMBus host's power management system display as both anidentifier and as an advertisement for the manufacturer. The name is also useful as part of the informationrequired to uniquely identify a battery.
SMBus protocol: Read block
Output: String—character string with maximum length of 11 characters (11 + length byte).
Description: This function returns a character string that contains the battery name. For example, aDeviceName() of bq2084-V140 indicates that the battery is a model bq2084-V140. The bq2084-V140 setsDeviceName() to the value programmed in Device Name DF 0x1a-0x21. When Misc Configuration 2 SSTRINGis set then the extended device name data flash is appended (0x141-0x14f)
Purpose: The DeviceName() function returns the battery name for identification purposes.
SMBus protocol: Read block
Output: String—character string with maximum length of 7 characters (7 + length byte).
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DeviceChemistry() (0x22)
The ManufacturerData() (0x23)
Pack Status and Pack Configuration (0x2f)
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Description: This function returns a character string that contains the battery chemistry. For example, if theDeviceChemistry() function returns NiMH, the battery pack contains nickel metal hydride cells. The bq2084-V140sets DeviceChemistry() to the value programmed in Device Chemistry DF 0x22-0x26.
Purpose: The DeviceChemistry() function gives cell chemistry information for use by charging systems. Thebq2084-V140 does not use DeviceChemisty() values for internal charge control or fuel gauging.
SMBus protocol: Read block
Output: String—character string with maximum length of 4 characters (4 + length byte).
The following is a partial list of chemistries and their expected abbreviations. These abbreviations are not casesensitive.
CHEMISTRY ABBREVIATIONS
Lead acid PbAcLithium ion LIONNickel cadmium NiCdNickel metal hydride NiMHNickel zinc NiZnRechargeable alkaline-manganese RAMZinc air ZnAr
Description: This function allows access to the manufacturer data contained in the battery (data). Thebq2084-V140 stores seven critical operating parameters in this data area.
Purpose: The ManufacturerData() function may be used to access the manufacturer's data area. The data fieldsof this command reflect the programming of eight critical data flash locations and can be used to facilitateevaluation of the bq2084-V140 under various programming sets. The ManufacturerData() function returns thefollowing information in order: Pack Configuration, Gauge Configuration, Misc Configuration (2 bytes), DigitalFilter, Self Discharge Rate, Pack Load Estimate, Battery Low%, and Near Full (2 bytes) AFE Status, and thepending EDV threshold voltage (low byte and high byte).
SMBus protocol: Read block
Output: Block data—data that reflects data flash programming as assigned by the manufacturer with maximumlength of 13 characters (13 + length byte).
This function returns the pack status and pack configuration registers. The pack status register contains anumber of status bits relating to bq2084-V140 operation. The pack status register is the least significant byte ofthe word. The pack configuration register reflects how the bq2084-V140 is configured as defined by the valueprogrammed in Pack Configuration in DF 0x28.
The pack status register consists of the following bits:b7 b6 b5 b4 b3 b2 b1 b0PRES EDV2 SS VDQ AFEFAIL PF CVOV CVUV
PRES
The PRES bit indicates that the bq2084-V140 has been inserted into the system.0 bq2084-V140 is out of the system1 bq2084-V140 is inserted into a system
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VCELL4-VCELL1 (0x3c-0x3f)
DATA FLASH
General
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
EDV2
The EDV2 bit indicates that pack or cell voltage (program option) is less than the EDV2 threshold.0 Voltage > EDV2 threshold (discharging)1 Voltage = EDV2 thresholdSS
The SS bit indicates the seal state of the bq2084-V140.0 The bq2084-V140 is in the unsealed state.1 The bq2084-V140 is in the sealed state.AFEFAIL
The AFEFAIL bit indicates that AFE communications has failed.0 AFE communications are okay.1 AFE communications have failed.VDQ
The VDQ bit indicates if the present discharge cycle is valid for an FCC update.0 Discharge cycle not valid1 Discharge cycle validPF
The PF bit indicates that the bq2084-V140 PF Flag has been set. It is cleared only when the PF Flag has beencleared.
0 bq2084-V140 PF Flag = 0x001 bq2084-V140 PF Flag = 0x66CVOV
The CVOV bit indicates that a protection limit has been exceeded including Prolonged Overcurrent,Overvoltage, or Overtemperature conditions. The bit is not latched and merely reflects the present fault status.0 No secondary protection limits exceeded1 A secondary protection limit exceededCVUV
The CVUV bit indicates that a protection limit has been exceeded including overload or overdischargeconditions. The bit is not latched and merely reflects the present fault status.0 No secondary protection limits exceeded1 A secondary protection limit exceeded
These functions return the calculated individual cell voltages in mV. If NVCELL is set in Misc Configuration 2then the SMBus commands are changed to 0x38-0x3b). The alternative commands are NACK'ed when notselected.
The bq2084-V140 accesses the internal data flash during reset and when storing historical data. The data flashstores basic configuration information for use by the bq2084-V140. The data flash must be programmedcorrectly for proper bq2084-V140 operation.
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Memory Map
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The following table shows the memory map for the data flash. It shows the default programming for thebq2084-V140. The default programming reflects example data for a 3s2p Li-ion battery pack with a 0.02- Ωsense resistor. The data flash must be reprogrammed to meet the requirements of individual applications.DATA FLASH ADDRESS DATANAME LI-ION EXAMPLEHIGH BYTE LOW BYTE MSB LSB
0x00 0x01 Remaining Time Alarm 10 minutes 00 0a0x02 0x03 Remaining Capacity Alarm 360 mAh 01 680x04 0x05 Design Voltage 14400 mV 38 400x06 0x07 Specification Information v1.1/PEC 00 310x08 0x09 Manufacture Date 1/1/2003=11809 2e 210x0a 0x0b Serial Number 1 00 010x0c 0x0d Cycle Count 0 00 000x0e Manufacturer Name Length 11 0b0x0f Character 1 T 540x10 Character 2 e 450x11 Character 3 x 580x12 Character 4 a 410x13 Character 5 s 530x14 Character 6 200x15 Character 7 I 490x16 Character 8 n 4e0x17 Character 9 s 530x18 Character 10 t 540x19 Character 11 . 2e0x1a Device Name Length 6 060x1b Character 1 b 420x1c Character 2 q 510x1d Character 3 2 320x1e Character 4 0 300x1f Character 5 8 380x20 Character 6 4 340x21 Character 7 — 000x22 Device Chemistry Length 4 040x23 Character 1 L 4c0x24 Character 2 I 490x25 Character 3 O 4f0x26 Character 4 N 4e0x27 Manufacturer Data Length 9 090x28 Pack Configuration DMODE, 4-LEDs, 4-CELL c30x29 Gauge Configuration CSYNC, OTVC 410x2a 0x2b Misc Configuration OT, VOD 0b 000x2c Digital Filter (Dead Band) 9860 nV 220x2d Self-Discharge Rate 0.2% 140x2e Electronics Load 0 mA 000x2f Battery Low % (MSB) 7.03% 120x30 0x31 Near Full 200 mAh 00 c80x32 0x33 Design Capacity 7200 mAh 1c 200x34 0x35 Reserved 0 00 00
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
DATA FLASH ADDRESS DATANAME LI-ION EXAMPLEHIGH BYTE LOW BYTE MSB LSB
0x36 0x37 Full Charge Capacity 7200 mAh 1c 200x38 0x39 Cycle Count Threshold 5200 mAh 14 500x3a 0x3b Charging Voltage 16800 mV 41 a00x3c 0x3d Precharge Voltage 2500 mV 09 c40x3e 0x3f Fast-Charging Current 2500 mA 09 c40x40 0x41 Maintenance Charging Current 0 mA 00 000x42 0x43 Precharge Current 100 mA 00 640x44 Precharge Temperature 9.6 °C 600x45 Precharge Temperature Hysteresis 3.0 °C 1e0x46 Charge Inhibit Temp Low 0.0 °C 000x47 0x48 Charge Inhibit Temp High 50 °C 01 f40x49 Fast Charge Termination % 100% ff0x4a Fully Charged Clear % 95% 5f0x4b 0x4c Current Taper Threshold 240 mA 00 f00x4d 0x4e Current Taper Qual Voltage 300 mV 01 2c0x4f Current Taper Window 40s 280x50 Reserved 400x51 0x52 Maximum Overcharge 300 mAh 01 2c0x53 Reserved 020x54 Charge Efficiency 100% ff0x55 Reserved 640x56 0x57 Reserved 02 220x58 Reserved 320x59 0x5a Reserved 01 ae0x5b 0x5c Overload Current 5000 mA 13 880x5d 0x5e Over Voltage Margin 700 mV 02 bc0x5f 0x60 Reserved 01 f40x61 0x62 Clear Fail Current 256 mA 01 000x63 0x64 Cell Over Voltage 4350 mV 10 fe0x65 0x66 Cell Under Voltage 2300 mV 08 fc0x67 0x68 Terminate Voltage 11300 mV 2c 240x69 0x6a Reserved 00 000x6b 0x6c Safety Over Voltage 20000 mV 3a 980x6d 0x6e Charge Suspend Temp High 60 °C 02 580x6f 0x70 Charge Suspend Temp High Reset 55 °C 02 260x71 0x72 Over Temperature Discharge 70 °C 02 bc0x73 0x74 Over Temperature Discharge Reset 60 °C 02 580x75 0x76 Safety OverTemperature Charge 75 °C 02 ee0x77 0x78 Safety OverTemperature Discharge 75 °C 02 ee0x79 Charge Suspend Temp Low 0°C 000x7a Reserved ef0x7b Current Deadband 3 mA 030x7c 0x7d Shutdown Voltage 8800 mV 22 600x7e 0x7f VOC75 15848 mV 3d e80x80 Reserved bf0x81 Reserved 560x82 Reserved 40
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
DATA FLASH ADDRESS DATANAME LI-ION EXAMPLEHIGH BYTE LOW BYTE MSB LSB
0x83 0x84 VOC50 15240 mV 3b 880x85 Reserved 7f0x86 Reserved 3d0x87 Reserved 270x88 0x89 VOC25 15024 mV 3a b00x8a Reserved 3f0x8b Reserved 240x8c Reserved 0e0x8d Reserved 140x8e Voltage Average Time 1 s 010x8f Correction Current Limit 64 mA 400x90 0x91 Reserved 0b e10x92 0x93 Reserved 0b 680x94 Reserved 190x95 0x96 EMF/EDV0 3000 mV 0b b80x97 0x98 EDV C0 Factor/EDV1 3250 mV 0c b20x99 0x9a EDV R0 Factor/EDV2 3400 mV 0d 480x9b 0x9c EDV T0 Factor 0 00 000x9d 0x9e EDV R1 Factor 0 00 000x9f EDV TC Factor 0 000xa0 EDV C1 Factor 0 000xa1 Reserved 080xa2 Reserved 9b0xa3 Reserved c70xa4 Reserved 640xa5 Reserved 140xa6 0xa7 Reserved 02 000xa8 0xa9 Reserved 01 000xaa Reserved 080xab Reserved 020xac Learning Low Temp 11.9 °C 770xad Reserved 0a0xae 0xaf Reserved 01 800xb0 0xb1 Reserved 01 000xb2 Reserved 080xb3 Reserved 180xb4 Reserved 140xb5 0xb6 TS Const 1 91 830xb7 0xb8 TS Const 2 51 700xb9 0xba TS Const 3 e2 8f0xbb 0xbc TS Const 4 0f ac0xbd 0xbe TS Const 5 00 000xbf 0xc0 Reserved 0f ac0xc1 Reserved 020xc2 AFE State Control 000xc3 AFE Function Control 000xc4 AFE Cell Select 00
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
DATA FLASH ADDRESS DATANAME LI-ION EXAMPLEHIGH BYTE LOW BYTE MSB LSB
0xc5 AFE Overload 140 mV 120xc6 AFE Overload Delay 31 ms 0f0xc7 AFE Short Circuit Charge 170xc8 AFE Short Circuit Discharge 170xc9 0xca AFE Vref*
(1)
9750 mV 26 160xcb 0xcc Sense Resistor Gain*
(1)
0.02 & 3b d00xcd 0xce CC Delta*
(1)
0.0000323 mAh 92 0a0xcf 0xd0 CC Delta*
(1)
16 000xd1 Reserved fa0xd2 0xd3 CC Offset*
(2)
49701 c2 250xd4 DSC Offset*
(2)
38 260xd5 ADC Offset*
(2)
38 260xd6 Temperature Offset*
(1)
0 000xd7 Board Offset*
(1)
0 000xd8 0xd9 Reserved 00 400xda 0xdb Reserved 01 000xdc Reserved 050xdd 0xde Version 1.0 01 000xdf Reserved 00 320xe0 0xe1 Cell Over Voltage Reset 4150 mV 10 360xe2 0xe3 Cell Under Voltage Reset 3000 mV 0b b80xe4 0xe5 AFE Fail Limit 2 counts 00 020xe6 0xe7 Reserved ff ff0xe8 0xe9 Cell Balance Thresh 3900 mV 0f 3c0xea 0xeb Cell Balance Window 100 mV 00 640xec Cell Balance Min 40 mV 280xed Cell Balance Interval 20 s 140xee 0xef Cell Imbalance Threshold 01 f40xf0 0xf1 Balance Vcell Max 10 360xf2 0xf3 Balance Imax 00 9e0xf4 0xf5 Reserved a5 5a0xf6 0xf7 Reserved 7a 430xf8 0xf9 Reserved 20 830xfa Battery Low (LSB) 7.03 % 120xfb AFE Check Time 0 s 000xfc Sleep Current Thresh 2 mA 040xfd Sleep Current Multiplier 5 counts 050xfe Sleep Time 20 s 140xff 0x100 Manufacturer Info 1 00 000x101 0x102 Manufacturer Info 2 00 000x103 0x104 Manufacturer Info 3 00 000x105 0x106 Vmax Charge Voltage 4280 mv 10 b80x107 0x108 Voff Charge Voltage 4280 mv 10 b80x109 0x10a Von Charge Voltage 4200 mv 10 68
(1) Reserved locations must be set as shown. Locations marked with an * are typical calibration values that can be adjusted for maximumaccuracy. For these locations, the table shows the appropriate default or initial setting.(2) Reserved locations must be set as shown. Locations marked with an * are typical calibration values that can be adjusted for maximumaccuracy. For these locations, the table shows the appropriate default or initial setting.
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
DATA FLASH ADDRESS DATANAME LI-ION EXAMPLEHIGH BYTE LOW BYTE MSB LSB
0x10b 0x10c Pulse Max On Time 60 s 01 e00x10d 0x10e Pulse Min Off Time 0.125 s 00 010x10f 0x110 Max Charge Time 7200 s 1c 200x111 0x112 Precharge Detection Current 10 mA 00 0a0x113 0x114 Charge Detection Current 100 mA 00 640x115 0x116 Discharge Detection Current -150 mA ff 6a0x117 0x118 Reserved 10 680x119 0x11a Reserved 10 360x11b 0x11c Reserved 000x11d Permanent Fail Status 0 000x11e Permanent Fail Flag 0 000x11f Permanent Fail Config 0 000x120 Permanent Fail Input Time 0 000x121 0x122 Reserved 17 120x123 0x124 Reserved 26 730x125 0x126 FET Fail Charge Current 20 mA 00 200x127 0x128 FET Fail Discharge Current -20 mA ff ec0x129 FET Fail Time 20 s 140x12a 0x12b Charge OC Threshold 4000 mA 0f a00x12c Charge OC Time 6 s 060x12d 0x12e Discharge OC Threshold 10970 mA 2a da0x12f Discharge OC Time 10 s 000x130 Fault Reset Time 30 s 1e0x131 0x132 VPACK Threshold 07 d00x133 Shutdown Timer 20 s 140x134 Cell Imbalance Time 20 s 140x135 0x136 Reserved0x137 0x138 EDV0 3000mV 0b b80x139 Misc Configuration 2 000x13a 13b Reserved ff ff0x13c 13d Reserved ff ff0x13e 13f Reserved ff ff0x140 Aux Device Name Length 0 bytes 000x141 0x14f Aux Device Name 00 000x150 Aux Manufacturer Name Length 0 bytes 000x151 0x15f Aux Manufacturer Name 00 000x160 AFE Recovery 3s 030x161 AFE Holdoff 30s 1e0x162 Over Temperature Time 10s 0a0x163 0x164 Reserved 00 0a0x165 Reserved 0a
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ADDITIONAL PROGRAMMING INFORMATION
ADDITIONAL DATA FLASH PROGRAMMING
Fundamental Parameters
Sense Resistor Value
CELL AND PACK CHARACTERISTICS
Battery Pack Capacity and Voltage
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
The following sections describe the function of each data flash location and how the data is to be stored.
The 32-bit CC Delta DF 0xcd-0xd0 corrects the coulomb counter for sense resistor variations. It represents thegain factor for the coulomb counter. The 16-bit Sense Resistor Gain in DF 0xcb-0xcc scales each integratingconverter conversion to mAh. The Current() related measurement Sense Resistor Gain is based on theresistance of the series sense resistor. The following formula computes a nominal or starting value for SenseResistor Gain from the sense resistor value (in Ω).Sense Resistor Gain = 306.25/Rs
RSNS Value (m Ω)Sense Resistor Gain
5 6125010 3062520 15312
CC offset
CC offset DF 0xd2-0xd3, contains the offset for the coulomb counter. It is automatically updated when the packhas met the conditions for sleep, before it enters sleep mode.DSC offset
DSC offset DF 0xd4, contains the offset for the pack ground reference. It is automatically updated when thepack has met the conditions for sleep, before it enters sleep mode.ADC offset
ADC offset DF 0xd5, contains the offset for the a/d converter. It is automatically updated when the pack hasmet the conditions for sleep, before it enters sleep mode.Digital FilterThe desired digital filter threshold, VDF (V), is set by the value stored in Digital Filter DF 0x2c.Digital Filter = VDF / 290 nV
Pack capacity in mAh units is stored in Design Capacity, DF 0x32-0x33. In mAh mode, the bq2084-V140 copiesDesign Capacity to DesignCapacity(). In mWh mode, the bq2084-V140 multiplies Design Capacity by DesignVoltage DF 0x04-0x05 to calculate DesignCapacity() scaled to 10 mWh. Design Voltage is stored in mV.
The initial value for Full Charge Capacity, in mAh, is stored in DF 0x36-0x37. Full Charge Capacity is modifiedover the course of pack usage to reflect cell aging under the particular use conditions. The bq2084-V140updates Full Charge Capacity in mAh after a capacity learning cycle.
Remaining Time Alarm and Capacity Alarm
Remaining Time Alarm in DF 0x02-0x03 set the alarm thresholds used in the SMBus command codes 0x01 and0x02, respectively. Remaining Time Alarm is stored in minutes and Remaining Capacity Alarm in units of mAh or10 mWh, depending on the BatteryMode() setting.
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PACK OPTIONS
Pack Configuration
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Cycle Count Initialization
Cycle Count DF 0x0c-0x0d stores the initial value for the CycleCount() function. It should be programmed to0x0000.
Cycle Count Threshold
Cycle Count Threshold 0x37-0x38 sets the number of mAh that must be removed from the battery to incrementCycleCount(). Cycle Count threshold is a 16-bit value stored in mAh.
Charge Efficiency
The bq2084-V140 applies the efficiency factor, EFF%, to all charge added to the battery. EFF% is encoded inCharge Efficiency DF 0x54 according to the following equation:Charge Efficiency = (EFF% w 2.56-1)
Pack Configuration DF 0x28 contains bit-programmable features.b7 b6 b5 b4 b3 b2 b1 b0
DMODE LED1 LED0 HPE CPE SM CC1 CC0
DMODE
The DMODE bit determines whether the LED outputs indicate AbsoluteStateOfCharge() orRelativeStateOfCharge().
0 LEDs reflect AbsoluteStateOfCharge()
1 LEDs reflect RelativeStateOfCharge()
LED1–LED0
The LED bits set the number of LEDs for Remaining Capacity () indication.0-0 Configures the bq2084-V140 for five LEDs0-1 Configures the bq2084-V140 for three LEDs1-0 Configures the bq2084-V140 for four LEDs1-1 Configures the bq2084-V140 for five LEDsHPE
The HPE bit enables/disables PEC transmissions to the smart battery host for master mode alarm messages.0 No PEC byte on alarm warning to host1 PEC byte on alarm warning to hostCPE
The CPE bit enables/disables PEC transmissions to the smart battery charger for master mode messages.0 No PEC byte on broadcasts to charger1 PEC byte on broadcasts to chargerSM
The SM bit enables/disables master mode broadcasts by the bq2084-V140.0 Broadcasts to host and charger enabled1 Broadcasts to host and charger disabledIf the SM bit is set, modifications to bits in BatteryMode() do not re-enable broadcasts.
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Gauge Configuration
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
CC1–CC0
The CC bits configure the bq2084-V140 for the number of series cells in the battery pack.1-1 Configures the bq2084-V140 for four series cells1-0 Configures the bq2084-V140 for three series cells0-1 Configures the bq2084-V140 for two series cells
Gauge Configuration DF 0x29 contains bit-programmable features:b7 b6 b5 b4 b3 b2 b1 b0
FEDV0 CSYNC SC CEDV EDVV OVSEL VCOR OTVC
FEDV0
When this bit is set, the EDV0 voltage is fixed while the EDV1 and EDV2 are left as compensated values ifCEDV is also set. When this bit is set, the compensated values of EDV1 and EDV2 are limited from goingbelow EDV0.
0 EDV0 acted upon per CEDV bit setting1 EDV0 fixed regardless of CEDV settingCSYNC
In usual operation of the bq2084-V140, the CSYNC bit is set so that the coulomb counter is adjusted when afast charge termination is detected. In some applications, especially those where an externally controlledcharger is used, it may be desirable not to adjust the coulomb counter. In these cases the CSYNC bit shouldbe cleared.
0 The bq2084-V140 does not alter RM at the time of a valid charge termination.1 The bq2084-V140 updates RM with a programmed percentage of FCC at a valid charger termination.SC
The SC bit enables learning cycle optimization for a Smart Charger or independent charge.1 Learning cycle optimized for independent charger0 Learning cycle optimized for Smart ChargerCEDV
The CEDV bit determines whether the bq2084-V140 implements automatic EDV compensation to calculate theEDV0, EDV1, and EDV2 thresholds base on rate, temperature, and capacity. If the bit is cleared, thebq2084-V140 uses the fixed values programmed in data flash for EDV0, EDV1, and EDV2. If the bit is set, thebq2084-V140 calculates EDV0, EDV1, and EDV2.0 EDV compensation disabled1 EDV compensation enabledEDVV
The EDVV bit selects whether EDV termination is to be done with regard to Voltage () or the lowest single-cellvoltage.
0 EDV conditions determined on the basis of the lowest single-cell voltage1 EDV conditions determined on the basis of Voltage()OVSEL
The OVSEL bit determines if Safety Over Voltage is based on Voltage () or highest cell voltages.0 Safety overvoltage based on Voltage ()
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Miscellaneous Configuration
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
1 Safety overvoltage based on highest cell voltage multiplied by the number of cells and then comparedto the safety voltage.VCOR
The VCOR bit enables the midrange voltage correction algorithm. When it is set, the bq2084-V140 comparesthe pack voltage to RM and may adjust RM according to the values programmed in VOC25, VOC50, andVOC75.
0 Continuous midrange corrections disabled1 Continuous midrange corrections enabledOTVC
The OTVC bit programs the bq2084-V140 to perform a midrange voltage one time after a device reset0 One-time midrange correction disabled1 One-time midrange correction enabled
Misc Configuration DF 0x2a (high) and 0x2b (low) contains additional bit programmable features.
Misc Configuration (high) DF 0x2ab15 b14 b13 b12 b11 b10 b9 b8
IT 0 AFEDET DS OT ECLED 1 VOD
IT
The IT bit configures the bq2084-V140 to use its internal temperature sensor. The DF constants 0xb5-0xc0need to match the required thermistor on internal temperature sensor. See the Data Flash Settings for Internalor External Temperature Sensor Table.0 bq2084-V140 requires an external thermistor.1 bq2084-V140 uses its internal temperature sensor.AFEDET
The AFEDET bit programs the bq2084-V140 to look for errors with I
2
C communications and the AFE andenables the detection of the AFE permanent failure if bit 3 of PF Config 0x11f is set.0 Does not verify AFE communications.1 Does verify AFE communications.DS
The DS bit programs the bq2084-V140 to enter sleep mode on SMBus inactivity.0 bq2084-V140 enters sleep mode when the SMBus is low for 2 s.1 bq2084-V140 does not enter sleep mode.OT
The OT bit enables the bq2084-V140 to turn off the FETs when the bq2084-V140 detects an overtemperaturecondition.
1 bq2084-V140 turns the appropriate FET off under over temperature conditions0 bq2084-V140 takes no FET action at all on over temperature conditionsECLED
The ECLED bit programs the LED activity during charging (DSG bit = 0).0 The LEDs are not enabled during charging.1 The LEDs are enabled during charging.
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bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
VOD
The VOD bit enables a 1-s time delay in the setting of the CVOV and CVUV bits in PackStatus.0 No delay1 1-s delay
Misc Configuration (low) DF 0x2bb7 b6 b5 b4 b3 b2 b1 b0LEDRCA PFET1 PFET0 NR CHGFET 0 0 DSGOT
LEDRCA
The LEDRCA bit programs the LED to blink when there is a RemainingCapacityAlarm.0 The LEDs blink when there is a RemainingCapacityAlarm.1 The LEDs are off when there is a RemainingCapacityAlarm.PFET1, PFET0The PFETx bits define the precharge FET operation. See the bq29312 data sheet for more detail.0,0 The bq29312 ZVCHG FET is turned on for precharge. Assumes charger has precharge function.0,1 The charge FET is turned on for precharge. Assumes charger has precharge function.1,0 The bq29312 OD FET is turned on for precharge. Assumes charger does not have precharge function.1,1 Not defined, unpredictable operationNR
The NR bit defines whether the bq2084-V140 is to be used with a nonremovable system battery. If set toindicate a nonremovable system battery there are additional clear conditions for a battery failure due toovercharge, overcurrent, and overload. The additional conditions besides battery removal (defined as the losssystem present pin going high) are either detection of an opposite current of that caused the failure or whenAverageCurrent() is less than Clear Fail Current DF 0x61, 0x62 for a time defined by Fault Reset Time DF0x130. Also, for a nonremovable battery the charge FET is left on for discharge current failures and thedischarge FET is left on for charge current failures.0 Removable battery, battery fail conditions cleared by battery removal only.1 Nonremovable system battery.CHGFET
The CHGFET bit programs the charge FET to remain on even after a charge terminate condition.0 The charge FET is turned off after a charge termination condition.1 The charge FET is turned on after a charge termination condition.DSGOT
When this bit is set, it allows the DSG FET to remain on after overtemperature in charge conditions0 bq2084-V140 turns both FETs off during an overtemperature in charge1 bq2084-V140 only turns off the CHG FET during overtemperature in charge
Misc Configuration 2 (low byte) (0x139)b7 b6 b5 b4 b3 b2 b1 b00 0 SSTRING NVCELL CCDSG SOCL CVFC DEPFET
SSTRING
When this bit is set, it enables an additional 15 characters of storage for both SBS.ManufacturerName( ) andSBS.DeviceName( ). (Storage is in separate area of data flash)0 ManufacturerName( ) and DeviceName( ) strings are 11 and 7 characters respectively
56
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Constants and String Data
Specification Information
Manufacture Date
Serial Number
Manufacturer Name Data
Device Name Data
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
1 ManufacturerName( ) and DeviceName( ) strings are 26 and 22 characters respectivelyNVCELL
When this bit is set, it forces SBS.VCELL1..4( ) to be accessible via alternative commands.0 SBS.VCELL1..4( ) available via 0x3c-0x3f1 SBS.VCELL1..4( ) available via 0x38-0x3bCCDSG
When this bit is set, it forces SBS.ChargingCurrent( ) to be reported as 0 when SBS.BatteryStatus( )DISCHARGING is also set.0 SBS.ChargingCurrent( ) is not modified just because SBS.BatteryStatus( ) DISCHARGING is set.1 SBS.ChargingCurrent( ) is set to 0 when SBS.BatteryStatus( ) DISCHARGING is set.SOCL
When this bit is set, it limits both RSOC and ASOC to 99% until a valid charge termination is detected.0 RSOC and ASOC are not limited.1 RSOC and ASOC are limited to 99% until charge termination.CVFC
When this bit is set, it causes SBS.ChargingVoltage( ) to be set to 0 when SBS.BatteryStatus( ) FC = 1.0 SBS.ChargingVoltage( ) is not modified1 SBS.ChargingVoltage( ) is set to 0 when FC = 1DEPFET
When this bit is set, it enables the CHG FET to be turned on when in depleted mode and when the lowest cellvoltage reading is greater than the precharge voltage threshold0 No FET action taken1 CHG FET turned on
Specification Information DF 0x06-0x07 stores the default value for the SpecificationInfo() function. It is stored indata flash in the same format as the data returned by the SpecificationInfo().
Manufacture Date DF 0x08-0x09 stores the default value for the ManufactureDate() function. It is stored in dataflash in the same format as the data returned by the ManufactureDate().
Serial Number DF 0x0a-0x0b stores the default value for the SerialNumber() function. It is stored in data flash inthe same format as the data returned by the SerialNumber().
Manufacturer Name Length DF 0x0e stores the length of the desired string that is returned by theManufacturerName() function. Locations DF 0x0f-0x19 store the characters for ManufacturerName() in ASCIIcode.
Device Name Length DF 0x1a stores the length of the desired string that is returned by the DeviceName()function. Locations DF 0x1b-0x21 store the characters for DeviceName() in ASCII code.
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Device Chemistry Data
Manufacturers Data Length
Temperature Limits
Charge Suspend Temp Low
Charge Inhibit Temp Low
Charge Inhibit Temp High
Charge Suspend Temp High
Charge Suspend Temp High Reset
Over Temperature Discharge
Over Temperature Discharge Reset
Failure Detection Thresholds
Safety OverTemperature Charge
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Device Chemistry Length DF 0x22 stores the length of the desired string that is returned by theDeviceChemistry() function. Locations DF 0x23-0x26 store the characters for DeviceChemistry() in ASCII code.
Manufacturers Data Length DF 0x27 stores the length of the desired number of bytes that is returned by theManufacturersData() function. It should be set to 9.
The limits described below are extensions to those limits detailed in the safety and charging sections of this datasheet.
Charge Suspend Temp Low DF 0x79 sets the lowest temperature, in degrees C/10, at which normal operation isallowed. If the temperature falls below this limit, the pack goes into a temporary failure state, the charge FET isturned off, and the MAC status is set to system present. It is cleared when the pack warms, or the pack isremoved.
Charge Inhibit Temp Low DF 0x46 inhibits charging by setting ChargingCurrent() and ChargingVoltage() to 0and turn off the CHG FET. It is programmed in degrees C/10 and the range of -12.8 °C to 12.7 °C.
Charge Inhibit Temp High DF 0x47 - 0x48 inhibits charging by setting ChargingCurrent() and ChargingVoltage()to 0
Charge Suspend Temp High DF 0x6d-0x6e sets the highest temperature, in degrees C/10, at which chargingwill be allowed to continue. If this temperature is exceeded during charging, the pack goes into a temporaryfailure state, and the MAC status is set to system present. It is cleared when the pack cools belowOverTemperature Charge Reset, or ac adapter is removed, or the pack is removed. Charging can only resumewhen the temperature returns to within the charge start temperature limits.
Charge Suspend Temp High Reset DF 0x6f-0x70 sets the temperature, in degrees C/10, at which the packrecovers from Charge Suspend Temp High fault.
Over Temperature Discharge DF 0x71-0x72 sets the highest temperature, in degrees C/10, at which dischargingwill be allowed. If the pack exceeds this temperature, charge and discharge FETs are turned off, and MACstatus is set to system present. The pack returns to normal operation when the temperature falls below OverTemperature Discharge Reset, or if the pack is removed.
Over Temperature Discharge Reset DF 0x73-0x74 sets the temperature, in degrees C/10, at which the pack willrecover from Over Temperature Discharge Over temperature will also reset when the pack is removed from thesystem if not in the non-removable mode.
Safety OverTemperature Charge DF 0x75-0x76 sets the temperature, in degrees C/10, above which, duringcharging, the pack enters permanent failure, if the XSOTC bit in Permanent Failure Configuration is set.
58
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Safety OverTemperature Discharge
Charge Detection Current
Discharge Detection Current
FET Fail Charge Current
FET Fail Discharge Current
FET Fail Time
Terminate Voltage
Offsets and Limits
Temperature offset
Board offset
Current Deadband
Shutdown Voltage
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Safety OverTemperature Discharge DF 0x77-0x78 sets the temperature, in degrees C/10, above which, duringdischarging, the pack enters permanent failure, if the XSOTD bit in Permanent Failure Configuration is set.
Charge Detection Current DF 0x113-0x114 sets the threshold in milliamperes for detecting charge current. Thisis a signed value and is positive. This threshold is used for detecting cross-conduction, and ensuring that chargetermination is not improperly detected due to loss of charging current.
Discharge Detection Current DF 0x115-0x116 sets the threshold in milliamperes for detecting discharge current.This is a signed value and is negative. This threshold is used for detecting cross-conduction and determiningthat the charge FET should be turned on during discharge to reduce IR losses.
FET Fail Charge Current DF 0x125-0x126 sets the threshold in milliamperes for detecting current in a chargeFET which is turned off. This is a signed value and is positive.
FET Fail Discharge Current DF 0x127-0x128 sets the threshold in milliamperes for detecting current in adischarge FET which is turned off. This is a signed value and is negative.
FET Fail Time DF 0x129 sets the time in seconds that current must be detected in a FET which is turned off, inorder to determine that the FET has failed.
Terminate Voltage DF 0x67-0x68 ,sets the threshold below which the Terminate Discharge Alarm bit is set. Thealarm is cleared when the voltage rises above this threshold, if the CVUV bit in Pack Status is not set.
Temperature offset DF 0xd6, contains a signed offset for the pack's temperature measurements, in degreesC/10. It is set at board test during pack calibration.
Board offset DF 0xd7, contains a signed offset for the pack's coulomb counter measurements. If used, it is set atboard design time.
Current Deadband DF 0x7b, sets the threshold in mA below which a current measurement is not detected.
Shutdown Voltage DF 0x7c-0x7d sets the pack voltage below which the pack's electronics, including thebq2084-V140, is shut down to conserve power. All FETs are turned off by the AFE.
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APPLICATION INFORMATION
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Figure 7 shows a typical bq2084-V140-based battery pack application. The circuit consists of the bq29312 AFEIC, bq29400 second-level protection IC, LED, temperature measurement network, data flash connections, serialport, and the sense resistor. The data flash stores basic battery pack configuration information andmeasurement calibration values. The data flash must be programmed properly for bq2084-V140 operation.
60
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11
CELL
17
TOUT
16
XALERT
14
SDATA
10
WDI
13
SCLK
24
OD
22
PACK 18
REG
20
21
8
SR1 12GND
15
GND
9
SR2
bq29312
U2
R3 100
R4 1 k
0.1µF C3
R5 1 k
1 kR6
R7 1 k
C4
0.1µF
C5
0.1µF
C6
0.1µF
0.1µFC7
1
2
3
45
6
7
8
VC1
VC2
VC3
GND
OUT
VDD
CD
VC4
U1
bq29400 BAV99
D2 2N7002
Q1
JP1
3
3
12
F1
6A
2
100 k
R43
1
2N7002
Q2 3
2
1
C12
0.1µF
BAT54LT1
D3
Q3
BSS84
BAV99
D1
R11
100
R10
100
R9
100
R8
100
R2
100
C1
0.1µF0.1µF 0.1µF 0.1µF 0.1µF
C2 C8 C9 C10 C11
1µF 50 V
X1
X2
X3
X4
X5
BAT4P
BAT3P
BAT2P
BAT1P
BATIN
VCC
100 k
R45
100 k
R12
BAT
SLEEP
VC1
VC2
VC3
VC4
VC5
PMS
1
19
3
4
5
6
7
23
2
3
DSG ZVCHG CHG
R15
100
R16
100 0.1µF
C16 0.1µF
C18
0.1µF
C19 1
2
R1 .020 75 PPM
1
1
R20 100
C20
0.1µF
8.45 k
R19
4.7µF
C17
VCC
R13
5 k
R14
5 k R17
5 k BAT54LT1
D4
VCC
R44
100 k
R42 100 k
C21
0.47µF
R21
61.9 k
RT1
10 k
1
1
C13
0.1µFC14
0.1µF
Si4435DY
Q4
21
865
4 4
8765
4
2
31
Si4435DY
Q5
R18
1 M R22
300
1 W
R23
1 M
C22
0.047 µFSi4435DY
Q6
R27
C24 0.47µF
C25 68 PF
VCC
R28
10
C27 0.47µF
C28 68 PF
1
4
11
19
38
18
12
37
2
6
10
36
25
35
1
4
5
28
27
26 9 13 17
30
29
3
34
33
15
16
32
7
20
21
22
23
24
14
VSSA
VSSD
VDDD VDDA
8 31
VSSD
VSSD
PFIN
SAFE
NC
TS
SCLK
SDATA
NC
EVENT
CLKOUT
VIN
PU
PRES
SR1
SR2
MRST RBI NC DISP
VSSAVSSA
OC
VSSA/XCK1
ROSC/XCK2
SMBC
SMBD
FLT
NC
LED5
LED4
LED3
LED2
LED1
NC
bq2084
U3
R24 5 k
R25 100
C26
0.1µF3
1
SW1
2
4
VCC
100 k
R29
R34 470
R33 470
R32 470
R31 470
R30 470
VCC
2
1
GREEN
D5
2
12
12
12
1
GREEN
GREEN
GREEN
GREEN
D6
D7
D8
D9
R35
100 k
R37
100
R38
100
R36 61.9 k
C30 2200 pF
C29 150 pF
R41 100
R40 100
D11
AZ23C5V6
SMBC
SMBD X8
X9
D10
AZ23C5V6
R39 100
Sys Pres X7
PACK− X10
4
3
2
1
1 M
7
865
7
3
21
3
R46
1 M1 M R47
1 M
0.47 µF
bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
APPLICATION INFORMATION (continued)
Figure 7. bq2084-V140 Based Battery Pack Schematic
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PACKAGE OPTION ADDENDUM
www.ti.com 17-Aug-2012
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status (1) Package Type Package
Drawing Pins Package Qty Eco Plan (2) Lead/
Ball Finish MSL Peak Temp (3) Samples
(Requires Login)
BQ2084DBTR-V140 NRND TSSOP DBT 38 TBD Call TI Call TI
BQ2084DBTR-V140G4 NRND TSSOP DBT 38 TBD Call TI Call TI
BQ2084RTTR-V140 NRND VQFN RTT 36 3000 TBD Call TI Call TI
BQ2084RTTR-V140G4 NRND VQFN RTT 36 3000 TBD Call TI Call TI
BQ2084RTTT-V140 NRND VQFN RTT 36 TBD Call TI Call TI
BQ2084RTTT-V140G4 NRND VQFN RTT 36 TBD Call TI Call TI
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
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