BQ27350 Datasheet, PDF (12/33 Pages) Texas Instruments – Single Cell Li-Ion Battery Manager With Impedance Track Fuel Gauge Technology

bq27350
Single Cell Li-Ion Battery Manager
With Impedance Track Fuel Gauge Technology
SLUS754 – MARCH 2007
Table 4-5. Flags Bit Definitions
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bit7
bit6
bit5
bit4
bit3
bit2
bit1
bit0
High Byte
OTC
OTD
–
–
–
XCHG
CHG_INH
CHG
Low Byte
CC_OFF
–
–
–
FC
RCA
TDA
DSG
OTC = Over-Temperature in Charge condition is detected
CC_OFF = Coulomb Counter Offset measurement is being performed
OTD = Over-Temperature in Discharge condition is detected
FC = Fully Charged, set when Charge termination condition is met
RCA = Remaining Capacity Alert
XCHG = Charge Suspend Alert (temp outside the range –5°C to 55°C)
CHG_INH = Charge Inhibit: unable to begin charging (temp outside the range 0°C to 45°C)
TDA = Terminate Discharge Alert
CHG = (Fast)charging allowed
DSG = Discharging detected
4.1.1.7 NominalAvailableCapacity( ): 0x0c/0x0d
This read-only command pair returns the uncompensated (no or light load) battery capacity remaining.
Units are 1mAh per bit.
4.1.1.8 FullAvailableCapacity( ): 0x0e/0x0f
This read-only command pair returns the uncompensated (no or light load) capacity of the battery when
fully charged. Units are 1mAh per bit. FullAvailableCapacity( ) is updated at regular intervals, as specified
by the IT algorithm.
4.1.1.9 RemainingCapacity( ): 0x10/0x11
This read-only command pair returns the compensated battery capacity remaining. Units are 1mAh per bit.
4.1.1.10 FullChargeCapacity( ): 0x12/13
This read-only command pair returns the compensated capacity of the battery when fully charged. Units
are 1mAh per bit. FullChargeCapacity( ) is updated at regular intervals, as specified by the IT algorithm.
4.1.1.11 AverageCurrent( ): 0x14/0x15
This read-only command pair returns a signed integer value that is the average current flow through the
sense resistor. It is updated every 1 second. Units are 1mA per bit.
4.1.1.12 TimeToEmpty( ): 0x16/0x17
This read-only function returns an unsigned integer value of the predicted remaining battery life at the
present rate of discharge, in minutes. A value of 65535 indicates battery is not being discharged.
4.1.1.13 TimeToFull( ): 0x18/0x19
This read-only function returns an unsigned integer value of predicted remaining time until the battery
reaches full charge, in minutes, based upon AverageCurrent( ). The computation should account for the
taper current time extension from the linear TTF computation based on a fixed AverageCurrent( ) rate of
charge accumulation. A value of 65535 indicates the battery is not being charged.
4.1.1.14 StandbyCurrent( ): 0x1a/0x1b
This read-only function returns a signed integer value of the measured standby current through the sense
resistor. The StandbyCurrent( ) is an adaptive measurement. Initially it reports the standby current
programmed in Initial Standby, and after spending some time in standby, reports the measured standby
current.
The register value is updated every 1 second when the measured current is above the Deadband (3mA
default) and is less than or equal to 2 x Initial Standby. The first and last values that meet this criteria
should not be averaged in, since they may not be stable values. To approximate a 1 minute time constant,
each new StandbyCurrent( ) value is computed as follows:
StandbyCurrent( )_NEW = (239/256) × StandbyCurrent( )_OLD + (17/256) × AverageCurrent( ).
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GENERAL DESCRIPTION
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