BQ2085 Datasheet, PDF (31/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085
SLUS541 – OCTOBER 2002
Units
Range
Granularity
Accuracy
BATTERY MODES
CAPACITY_MODE
BIT = 0
CAPACITY_MODE
BIT = 1
mAh
10 mWh
0–65,535 mAh
0–65,535 10 mWh
mAh
10 mWh
–0, +MaxError( ) _* FullCharageCapacity( )
RunTimeToEmpty( ) (0x11)
Description: Returns the predicted remaining battery life at the present rate of discharge (minutes). The
RunTimeToEmpty( ) value is calculated based on either current or power depending on the setting of the
BatteryMode( ) CAPACITY_MODE bit.
Purpose: The RunTimeToEmpty( ) provides the power management system with information about the relative
gain or loss in remaining battery life in response to a change in power policy. This information is not the same
as the AverageTimeToEmpty( ), which is not suitable to determine the effects that result from a change in power
policy.
SMBus protocol: Read word
Output: Unsigned integer—minutes of operation left.
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
Accuracy: –0, +MaxError( ) _* FullChargeCapacity( ) / Current( )
Invalid Data Indication: 65,535 indicates battery is not being discharged.
AverageTimeToEmpty( ) (0x12)
Description: Returns a one-minute rolling average of the predicted remaining battery life (minutes). The
AverageTimeToEmpty( ) value is calculated based on either current or power depending on the setting of the
BatteryMode( ) CAPACITY_MODE bit.
Purpose: The AverageTimeToEmpty( ) displays state-of-charge information in a more useful way. It averages
the instantaneous estimations so the remaining time does not appear to jump around.
SMBus protocol: Read word
Output: Unsigned integer—minutes of operation left.
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
Accuracy: –0, +MaxError( ) _* FullChargeCapacity( ) / AverageCurrent( )
Invalid Data Indication: 65,535 indicates battery is not being discharged.
AverageTimeToFull( ) (0x13)
Description: Returns a one-minute rolling average of the predicted remaining time until the battery reaches
full charge (minutes).
Purpose: The AverageTimeToFull( ) function can be used by the SMBus host’s power management system
to aid in its policy. It may also be used to find out how long the system must be left on to achieve full charge.
SMBus protocol: Read word
Output: Unsigned integer—remaining time in minutes.
Units: Minutes
Range: 0 to 65,534 minutes
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