BQ2084-V140_14 Datasheet, PDF (36/64 Pages) Texas Instruments – SBS v1.1-COMPLIANT GAS GAUGE FOR USE WITH THE bq29312

bq2084-V140
SLUS664B – JULY 2005 – REVISED AUGUST 2006
Accuracy: ± MaxError() * FullChargeCapacity()/|AtRate()|
Invalid Data Indication: 65,535 indicates the AtRate = 0.
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AtRateTimeToEmpty() (0x06)
Description: Returns the predicted remaining operating time if the battery is discharged at the AtRate() value.
Purpose: The AtRateTimeToEmpty() function is part of a two-function call-set used to determine the remaining
operating time at the AtRate() value. The bq2084-V140 updates AtRateTimeToEmpty() within 5 ms after the
SMBus host sets the AtRate() value. The bq2084-V140 automatically updates AtRateTimeToEmpty() based on
the AtRate() value every 1 s.
SMBus protocol: Read word
Output: Unsigned integer—estimated operating time left.
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
Accuracy: -0, +MaxError() × FullChargeCapacity/|AtRate()|
Invalid Data Indication: 65,535 indicates AtRate = 0.
AtRateOK() (0x07)
Description: Returns a Boolean value that indicates whether or not the battery can deliver the AtRate() value of
additional energy for 10 s. If the AtRate value is zero or positive, the AtRateOK() function ALWAYS returns OK
(logic 1).
Purpose: The AtRateOK() function is part of a two-function call-set used by power management systems to
determine if the battery can safely supply enough energy for an additional load. The bq2084-V140 updates
AtRateOK() within 5 ms after the SMBus host sets the AtRate() value. The bq2084-V140 automatically updates
AtRateOK() based on the At Rate() value every 1 second.
SMBus protocol: Read word
Output: Boolean—indicates if the battery can supply the additional energy requested.
Units: Boolean
Range: 1, 0
Granularity: Not applicable
Accuracy: Not applicable
Temperature() (0x08)
Description: Returns the temperature (K) measured by the bq2084-V140.
Purpose: The Temperature() function provides accurate cell temperatures for use by battery chargers and
thermal management systems. A battery charger can use the temperature as a safety check. Thermal
management systems may use the temperature because the battery is one of the largest thermal sources in a
system.
SMBus protocol: Read word
Output: Unsigned integer—cell temperature in tenth-degree Kelvin increments.
Units: 0.1°K
Range: 0 to +6553.5°K {real range}
Granularity: 0.1°K
Accuracy: ±1.5°K (from ideal Semitec 103AT thermistor performance, after calibration)
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