BQ2063_15 Datasheet, PDF (9/60 Pages) Texas Instruments – SBS v1.1-COMPLIANT Li-ION GAS-GAUGE IC

Not Recommended For New Designs
bq2063
SBS v1.1ĆCOMPLIANT LiĆION GASĆGAUGE IC
WITH PROTECTOR INTERFACE
SLUS468E− MAY 2001 − REVISED APRIL 2002
gas gauge operation (continued)
capacity learning (FCC update) and qualified discharge
The bq2063 updates FCC with an amount based on the value in DCR if a qualified discharge occurs. The new
value for FCC equals the DCR value plus the programmable nearly full and low battery levels, according to the
following equation:
FCC (new) + DCR (final) + DCR (initial) ) Measured Discharge to EDV2 ) (FCC Battery Low%)
(1)
Battery Low % = (value stored in EE 0x54) ÷ 2.56
A qualified discharge occurs if the battery discharges from RM ≥ FCC − Near Full × 2 to the EDV2 voltage
threshold with the following conditions:
D No valid charge activity occurs during the discharge period. A valid charge is defined as a charge of 10 mAh
into the battery.
D No more than 256 mAh of self-discharge, battery load estimation, and/or light discharge estimation occurs
during the discharge period.
D The temperature does not drop below the low temperature thresholds programmed in Max T_LowT or 12°C
during the discharge period. The threshold depends on the programming of the LLTF bit in Pack
Programming, EE 0x63.
D The battery voltage reaches the EDV2 threshold during the discharge period and the voltage was less than
the EDV2 threshold minus 256 mV when the bq2063 detected EDV2.
D No midrange voltage correction occurs during the discharge period.
D Current remains ≥ 3C/32 or C/32, depending on Pack Programming selection, when EDV2 or Battery Low
% level is reached.
The bq2063 sets VDQ=1 in Pack Status when qualified discharge begins. The bq2063 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 bq2063 saves the new FCC value to the EEPROM within 4
seconds of being updated.
end-of-discharge thresholds and capacity correction
The bq2063 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 Programming configures the bq2063 for overall voltage or single-cell EDV thresholds.
If programmed for single cell EDV determination, the bq2063 determines EDV on the basis of the lowest
single-cell voltage. Fixed EDV thresholds may be programmed in EDVF/EDV0 EE 0x72-0x73, EMF/EDV1 EE
0x74-0x75, and EDV C0 Factor/EDV2 EE 0x78-0x79. If the CEDV bit in Pack Configuration is set, automatic
EDV compensation is enabled and the bq2063 computes the EDV0, EDV1, and EDV2 thresholds based on the
values in EE 0x72-0x7d, 0x06, and the battery’s current discharge rate and temperature. The bq2063 disables
EDV detection if Current( ) exceeds the Overload Current threshold programmed in EE 0x46 − EE 0x47. The
bq2063 resumes EDV threshold detection after Current( ) drops below the overload current threshold. Any EDV
threshold detected is reset after 10 mAh of charge are applied.
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