BQ2084-V140_14 Datasheet, PDF (33/64 Pages) Texas Instruments – SBS v1.1-COMPLIANT GAS GAUGE FOR USE WITH THE bq29312

bq2084-V140
www.ti.com
SLUS664B – JULY 2005 – REVISED AUGUST 2006
RemainingTimeAlarm() (0x02)
Description: Sets or gets the Remaining Time Alarm value. Whenever the AverageTimeToEmpty() falls below
the remaining time value, the bq2084-V140 sends AlarmWarning() messages to the SMBus host with the
REMAINING_TIME_ALARM bit set. A remaining time value of 0 effectively disables this alarm. The
bq2084-V140 initially sets the remaining time value to the Remaining Time Alarm value programmed in DF
0x00-0x01. The remaining time value remains unchanged until altered by the RemainingTimeAlarm() function.
Purpose: The RemainingTimeAlarm() function can be used by systems that want to adjust when the remaining
time alarm warning is sent. The remaining time value can be read to verify the value in use by the bq2084-V140
RemainingTimeAlarm().
SMBus protocol: Read or write word
Input/Output: Unsigned integer—the point below which remaining time messages are sent.
Units: Minutes
Range: 0 to 65,535 minutes
Granularity: Not applicable
Accuracy: See AverageTimeToEmpty().
BatteryMode() (0x03)
Description: Selects the various battery operational modes and reports the battery's mode and requests.
Defined modes include
• Whether the battery capacity information is specified in units of mAh or 10 mWh (CAPACITY_MODE bit)
• Whether the ChargingCurrent() and ChargingVoltage() values are broadcast to the smart battery charger
when the CHARGER_MODE bit is set.
• Whether all broadcasts to the smart battery charger and host are disabled
The defined request condition is the battery requesting a conditioning cycle (RELEARN_FLAG).
Purpose: The CAPACITY_MODE bit allows power management systems to best match their electrical
characteristics with those reported by the battery. For example, a switching power supply represents a constant
power load, whereas a linear supply is better represented by a constant current model. The CHARGER_MODE
bit allows a SMBus host or smart battery charger to override the smart battery desired charging parameters by
disabling the bq2084-V140 broadcasts. The RELEARN_FLAG bit allows the bq2084-V140 to request a
conditioning cycle.
SMBus protocol: Read or write word
Input/Output: Unsigned integer—bit mapped—see Table 14.
Units: Not applicable
Range: 0-1
Granularity: Not applicable
Accuracy: Not applicable
The BatteryMode() word is divided into two halves, the MSB (bits 8-15) which is read/write and the LSB (bits
0-7) which is read only. The bq2084-V140 forces bits 0-6 to zero and prohibits writes to bit 7.
Table 14 summarizes the meanings of the individual bits in the BatteryMode() word. Specified default values,
where applicable, are noted. INTERNAL_CHARGE_CONTROLLER bit is not used by the bq2084-V140.
PRIMARY_BATTERY_SUPPORT bit is not used by the bq2084-V140.
RELEARN_FLAG bit set indicates that the bq2084-V140 is requesting a capacity relearn cycle for the battery.
The bq2084-V140 sets the RELEARN_FLAG on a full reset and if it detects 20-cycle counts without an FCC
update. The bq2084-V140 clears this flag after a learning cycle has been completed.
CHARGE_CONTROLLER_ENABLED bit is not used by the bq2084-V140. The bq2084-V140 forces this bit to
zero.
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