BQ2063_15 Datasheet, PDF (31/60 Pages) Texas Instruments – SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

Not Recommended For New Designs
bq2063
SBS v1.1ĆCOMPLIANT LiĆION GASĆGAUGE IC
WITH PROTECTOR INTERFACE
SLUS468E− MAY 2001 − REVISED APRIL 2002
command codes (continued)
AverageCurrent( ) (0x0b); [0x0b]
Description: Returns a value that approximates a one-minute rolling average of the current being supplied (or
accepted) through the battery terminals (mA). The AverageCurrent( ) function returns meaningful values during
the battery’s first minute of operation.
Purpose: The AverageCurrent( ) function provides the average current flowing into or out of the battery for the
power management system.
SMBus Protocol: Read Word
Output: Signed integer-charge/discharge rate in mA increments-positive for charge, negative for discharge.
Units: mA
Range: (± 250 mV/R_S) mA
Granularity: 0.038 mV/R_S (integer value)
Accuracy: ±0.4 mV/R_S (after calibration)
MaxError( ) (0x0c); [0x0c]
Description: Returns the expected margin of error (%) in the state of charge calculation. For example, when
MaxError( ) returns 10% and RelativeStateOfCharge( ) returns 50%, the Relative StateOfCharge( ) is more
likely between 50% and 60%. The bq2063 sets MaxError( ) to 100% on a full reset. The bq2063 sets MaxError( )
to 2% on completion of a learning cycle, unless the bq2063 limits the learning cycle to the +512/-256 mAh
maximum adjustment values. If the learning cycle is limited, the bq2063 sets MaxError( ) to 8% unless
MaxError( ) was already below 8%. In this case MaxError( ) does not change. The bq2063 increments
MaxError( ) by 1% after four increments of CycleCount( ) without a learning cycle.
If voltage-based corrections are applied to the coulomb counter, MaxError( ) is set to 25%.
Purpose: The MaxError( ) function has real value in two ways: first, to give the user a confidence level about
the state of charge and second, to give the power management system information about how aggressive it
should be, 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
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