BQ2085 Datasheet, PDF (28/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085
SLUS541 – OCTOBER 2002
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 bq2085 updates
AtRateOK( ) within 5 ms after the SMBus host sets the AtRate( ) value. The bq2085 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 bq2085.
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)
Voltage( ) (0x09)
Description: Returns the cell-pack voltage (mV).
Purpose: The Voltage( ) function provides power management systems with an accurate battery terminal
voltage. Power management systems can use this voltage, along with battery current information, to
characterize devices they control. This ability helps enable intelligent, adaptive power-management systems.
SMBus protocol: Read word
Output: Unsigned integer—battery terminal voltage in mV.
Units: mV
Range: 0 to 20,000 mV
Granularity: 1 mV
Accuracy: ±0.25% (after calibration)
Current( ) (0x0a)
Description: Returns the current being supplied (or accepted) by the battery (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: Read word
Output: Signed integer—charge/discharge rate in mA increments-positive for charge, negative for discharge.
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