BQ2060A_15 Datasheet, PDF (30/61 Pages) Texas Instruments – SBS v1.1-Compliant Gas Gauge IC

bq2060A
SLUS500D – OCTOBER 2001 – REVISED OCTOBER 2011
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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 bq2060A sets MaxError() to 100% on a full reset. The bq2060A sets MaxError() to
2% on completion of a learning cycle, unless the bq2060A limits the learning cycle to the +512/–256-mAh
maximum adjustment values. If the learning cycle is limited, the bq2060A sets MaxError() to 8% unless
MaxError() was already below 8%. In this case MaxError() does not change. The bq2060A 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% to 100%
• Granularity: 1%
• Accuracy: not applicable
RelativeStateOfCharge() (0x0d); [0x0d]
Description: Returns the predicted remaining battery capacity expressed as a percentage of
FullChargeCapacity() (%).
Purpose: The RelativeStateOfCharge() function is used to estimate the amount of charge remaining in the
battery relative to the last learned capacity.
SMBus Protocol: Read Word
Output:
Unsigned integer—percent of remaining capacity.
• Units: %
• Range: 0% to 100%
• Granularity: 1%
• Accuracy: –0, +MaxError()
AbsoluteStateOfCharge()(0x0e); [0x0e]
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 the
battery relative to the nominal or DesignCapacity().
SMBus Protocol: Read Word
Output:
RemainingCapacity() (0x0f); [0x0f]
Description: Returns the predicted charge or energy remaining in the battery. The RemainingCapacity() value is
expressed in either charge (mAh at a C/5 discharge rate) or energy (10 mWh at a P/5 discharge rate) depending
on the setting of the BatteryMode() CAPACITY_MODE bit.
Purpose: The RemainingCapacity() function returns the remaining battery capacity. This information is a numeric
indication of remaining charge or energy given by the Absolute or Relative StateOfCharge() functions and may
be in a better form for use by power management systems.
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