BQ27541 Datasheet, PDF (13/38 Pages) Texas Instruments – Single Cell Li-Ion Battery Fuel Gauge for Battery Pack Integration

bq27541
www.ti.com ........................................................................................................................................................................................... SLUS861 – DECEMBER 2008
CAL_MODE: 0X0040
This command instructs the fuel gauge to enter calibration mode. This command is only available when the fuel
gauge is UNSEALED
RESET : 0X0041
This command instructs the fuel gauge to perform a full reset. This command is only available when the fuel
gauge is UNSEALED.
AtRate( ): 0x02/0x03
The AtRate( ) read-/write-word function is the first half of a two-function command set used to set the AtRate
value used in calculations made by the AtRateTimeToEmpty( ) function. The AtRate( ) units are in mA.
The AtRate( ) value is a signed integer, with negative values interpreted as a discharge current value. The
AtRateTimeToEmpty( ) function returns the predicted operating time at the AtRate value of discharge. The
default value for AtRate( ) is zero and will force AtRateTimeToEmpty( ) to return 65,535. Both the AtRate( ) and
AtRateTimeToEmpty( ) commands should only be used in NORMAL mode.
AtRateTimeToEmpty( ): 0x04/0x05
This read-only function returns an unsigned integer value of the predicted remaining operating time if the battery
is discharged at the AtRate( ) value in minutes with a range of 0 to 65,534. A value of 65,535 indicates AtRate( )
= 0. The fuel gauge updates AtRateTimeToEmpty( ) within 1 s after the system sets the AtRate( ) value. The fuel
gauge automatically updates AtRateTimeToEmpty( ) based on the AtRate( ) value every 1s. Both the AtRate( )
and AtRateTimeToEmpty( ) commands should only be used in NORMAL mode.
Temperature( ): 0x06/0x07
This read-only function returns an unsigned integer value of the battery temperature in units of 0.1K measured by
the fuel gauge.
Voltage( ): 0x08/0x09
This read-only function returns an unsigned integer value of the measured cell-pack voltage in mV with a range
of 0 to 6000 mV.
Flags( ): 0x0a/0x0b
This read-only function returns the contents of the gas-gauge status register, depicting the current operating
status.
High Byte
Low Byte
bit7
OTC
––
Table 4. Flags Bit Definitions
bit6
OTD
–
bit5
bit4
bit3
bit2
–
–
CHG_INH
XCHG
–
–
–
SOC1
bit1
FC
SOCF
bit0
CHG
DSG
OTC = Over-Temperature in Charge condition is detected. True when set
OTD = Over-Temperature in Discharge condition is detected. True when set
CHG_INH =
Charge Inhibit indicates the temperature is outside the range [Charge Inhibit Temp Low, Charge Inhibit Temp
High]. True when set
XCHG =
Charge Suspend Alert indicates the temperature is outside the range [Suspend Temperature Low, Suspend
Temperature High]. True when set
FC = Full-charged condition reached (RMFCC=1; Set FC_Set%=-1% when RMFCC=0). True when set
CHG = (Fast) charging allowed. True when set
SOC1 = State-of-Charge-Threshold 1 (SOC1 Set) reached. True when set
SOCF = State-of-Charge-Threshold Final (SOCF Set %) reached. True when set
DSG = Discharging detected. True when set
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