BQ2060SS Datasheet, PDF (27/59 Pages) Texas Instruments – SBS V1.1-COMPLIANT GAS GAUGE IC

bq2060
www.ti.com
Accuracy: ±0.65% (after calibration)
SLUS035E – JANUARY 2000 – REVISED OCTOBER 2005
Current() (0x0a); [0x0a]
DESCRIPTION
Returns the current being supplied (or accepted) through the battery’s terminals (mA).
PURPOSE
The Current() function provides a snapshot for the power management system of the current
flowing into or out of the battery. This information is of particular use in power-management
systems because they can characterize individual devices and tune their operation to actual system
power behavior.
SMBus PROTOCOL ReadWord
OUTPUT
Signed integer—charge/discharge rate in mA increments—positive for charge, negative for
discharge.
Units: mA
Range: (±250 mV/RS) mA
Granularity: 0.038 mV/RS (integer value)
Accuracy: ±1 mV/RS (after calibration)
AverageCurrent() (0x0b); [0x0b]
DESCRIPTION
Returns a value that approximates a 1-minute rolling average of the current being supplied (or
accepted) through the battery’s 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 ReadWord
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: ±1m V/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 bq2060 sets MaxError() to 100% on a full reset. The
bq2060 sets MaxError() to 2% on completion of a learning cycle, unless the bq2060 limits the
learning cycle to the +512/–256 mAh maximum adjustment values. If the learning cycle is limited,
the bq2060 sets MaxError() to 8% unless MaxError() was already below 8%. In this case
MaxError() does not change. The bq2060 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
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