BQ2083-V1P3 Datasheet, PDF (11/56 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

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bq2083-V1P3
SLVS508 − OCTOBER 2003
D No more than 256 mAh of self-discharge or battery load estimation occurs during the discharge period.
D The temperature does not drop below the low temperature thresholds programmed in Learning Low Temp DF
0x9b when EDV2 is detected.
D The battery voltage reaches the EDV2 threshold during the discharge period and the voltage is greater than or
equal to the EDV2 threshold minus 384 mV when the bq2083−V1P3 detected EDV2.
D No midrange voltage correction occurs during the discharge period.
D Current remains ≥ 3C/32 when EDV2 or Battery Low % level is reached.
D No overload condition exists when EDV2 threshold is reached or if RM( ) has dropped to Battery Low% x FCC.
The bq2083−V1P3 sets VDQ=1 in pack status when qualified discharge begins. The bq2083−V1P3 sets VDQ=0 if
any disqualifying condition occurs. FCC cannot be reduced by more than 256 mAh or increased by more than
512 mAh during any single update cycle. The bq2083−V1P3 saves the new FCC value to the data flash within 4
seconds of being updated.
End-of-Discharge Thresholds and Capacity Correction
The bq2083−V1P3 monitors the battery for three low-voltage thresholds, EDV0, EDV1, and EDV2. The EDV
thresholds can be programmed for determination based on the overall pack voltage or an individual cell level. The
EDVV bit in Pack Configuration DF 0x28 configures the bq2083−V1P3 for overall voltage or single-cell EDV
thresholds. If programmed for single cell EDV determination, the bq2083−V1P3 determines EDV on the basis of the
lowest single-cell voltage. Fixed EDV thresholds may be programmed in EMF/EDV0 DF 0x84-0x85, EDV C0
Factor/EDV1 DF 0x86-0x87, and EDV R Factor/EDV2 DF 0x88-0x89. If the CEDV bit in Gauge Configuration DF
0x29 is set, automatic EDV compensation is enabled and the bq2083−V1P3 computes the EDV0, EDV1, and EDV2
thresholds based on the values in DF 0x84-0x8d and the battery’s current discharge rate and temperature. The
bq2083−V1P3 disables EDV detection if Current( ) exceeds the Overload Current threshold programmed in DF 0x58
− DF 0x59. The bq2083−V1P3 resumes EDV threshold detection after Current( ) drops below the Overload Current
threshold. Any EDV threshold detected is reset after charge is applied and VDQ is cleared after 10mAh of charge.
Table 2. State of Charge Based on Low Battery Voltage
THRESHOLD
EDV0
EDV1
EDV2
RELATIVE STATE
OF CHARGE
0%
3%
Battery Low %
The bq2083−V1P3 uses the EDV thresholds to apply voltage-based corrections to the RM register according to
Table 1. The bq2083−V1P3 performs EDV-based RM adjustments with Current( ) ≥ C/32. No EDVs are set if current
< C/32. The bq2083−V1P3 adjusts RM as it detects each threshold. If the voltage threshold is reached before the
corresponding capacity on discharge, the bq2083−V1P3 reduces RM to the appropriate amount as shown in Table
2. This reduction occurs only if current ≥ C/32 when the EDV threshold is detected. If RM reaches the capacity level
before the voltage threshold is reached on discharge, the bq2083−V1P3 prevents RM from decreasing further until
the battery voltage reaches the corresponding threshold only on a full learning cycle discharge. RM is not held at the
associated EDV percentage on a nonlearning discharge cycle (VDQ=0) or if current < C/32.
If Battery Low % is set to zero, EDV1 and EDV0 corrections are disabled.
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