BQ2085 Datasheet, PDF (26/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085
SLUS541 – OCTOBER 2002
CAPACITY_MODE bit indicates if capacity information is reported in mA/mAh or 10mW/10 mWh. When set,
the bq2085 reports capacity information in 10 mW/10 mWh as appropriate. When cleared, the bq2085 reports
capacity information in mA/mAh as appropriate. The CAPACITY_MODE bit defaults to a cleared state when the
bq2085 enters SLEEP mode.
The following functions are changed to accept or return values in mA/mAh or 10 mW/10 mWh depending on
the CAPACITY_MODE bit:
D RemainingCapacityAlarm( )
D AtRate( )
D RemainingCapacity( )
D FullChargeCapacity( )
D DesignCapacity( )
The following functions are calculated on the basis of capacity and may be calculated differently depending on
the CAPACITY_MODE bit:
D AtRateOK( )
D AtRateTimeToEmpty( )
D AtRateTimeToFull( )
D RunTimeToEmpty( )
D AverageTimeToEmpty( )
D AverageTimeToFull( )
D Remaining Time Alarm( )
D BatteryStatus( )
The bq2085 updates the non-AtRate related register values within 1 s of changing the state of the
CAPACITY_MODE bit. The AtRate( ) values are updated after the next AtRate value is written to the bq2085
(or after the next 1 s scheduled refresh calculation).
AtRate( ) (0x04)
Description: The AtRate( ) function is the first half of a two-function call-set used to set the AtRate value used
in calculations made by the AtRateTimeToFull( ), AtRateTimeToEmpty( ), and AtRateOK( ) functions. The
AtRate value may be expressed in either current (mA) or power (10 mW) depending on the setting of the
BatteryMode( ) CAPACITY_MODE bit.
Purpose: Since the AtRate( ) function is the first half of a two-function call-set, it is followed by the second
function of the call-set that calculates and returns a value based on the AtRate value and the battery’s present
state.
D When the AtRate( ) value is positive, the AtRateTimeToFull( ) function returns the predicted time to
full-charge at the AtRate value of charge.
D When the AtRate( ) value is negative, the AtRateTimeToEmpty( ) function returns the predicted operating
time at the AtRate value of discharge.
D When the AtRate( ) value is negative, the AtRateOK( ) function returns a Boolean value that predicts the
battery’s ability to supply the AtRate value of additional discharge energy (current or power) for 10 seconds.
The default value for AtRate( ) is zero.
SMBus protocol: Read or write word
26
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