BQ2084-V140_14 Datasheet, PDF (35/64 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
• AtRateTimeToFull()
• RunTimeToEmpty()
• AverageTimeToEmpty()
• AverageTimeToFull()
• Remaining Time Alarm()
• BatteryStatus()
The bq2084-V140 updates the non-AtRate related register values immediately after changing the state of the
CAPACITY_MODE bit. The AtRate() values are updated after the next AtRate() value is written to the
bq2084-V140 (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: Because 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.
• When the AtRate() value is positive, the AtRateTimeToFull() function returns the predicted time to full charge
at the AtRate value of charge.
• When the AtRate() value is negative, the AtRateTimeToEmpty() function returns the predicted operating time
at the AtRate value of discharge.
• 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
Input/Output: Signed integer-charge or discharge; the AtRate() value is positive for charge, negative for
discharge, and zero for neither (default).
Units
Charge range
Discharge range
Granularity
Accuracy
BATTERY MODES
CAPACITY_MODE
BIT = 0
CAPACITY_MODE
BIT = 1
mA
10 mW
1 to 32,767 mA
1 to 32,767 10 mW
–1 to –32,768 mA
–1 to –32,768 10 mW
1 Unit
NA
AtRateTimeToFull() (0x05)
Description: Returns the predicted remaining time to fully charge the battery at the AtRate() value (mA).
Purpose: The AtRateTimeToFull() function is part of a two-function call-set used to determine the predicted
remaining charge time at the AtRate value in mA. The bq2084-V140 updates AtRateTimeToFull() within 5 ms
after the SMBus host sets the AtRate value. The bq2084-V140 automatically updates AtRateTimeToFull() based
on the AtRate() value every 1 s.
SMBus protocol: Read word
Output: Unsigned integer—predicted time in minutes to fully charge the battery.
Units: Minutes
Range: 0 to 65,534 min
Granularity: 2 min or better
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