BQ2085-V1P3 Datasheet, PDF (45/57 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

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bq2085-V1P3
SLUS598 − FEBRUARY 2004
Change Control
Charging Voltage
The 16-bit value, Charging Voltage DF 0x39−0x3a programs the ChargingVoltage( ) value broadcast to a smart
charger. It also sets the base value for determining overvoltage conditions during charging and voltage
compliance during a constant-voltage charging methodology. It is stored in mV.
Over Voltage
The 16-bit value, Over Voltage Margin DF 0x5a−0x5b, sets the limit over ChargingVoltage( ) in mV that is to
be considered as an overvoltage charge-suspension condition.
Charging Current
ChargingCurrent( ) values are either broadcast to a Level 2 smart battery charger or read from the
bq2085−V1P3 by a Level 3 smart battery charger. The bq2085−V1P3 sets the value of ChargingCurrent( ),
depending on the charge requirements and charge conditions of the pack.
When fast charge is allowed, the bq2085−V1P3 sets ChargingCurrent( ) to the rate programmed in
Fast-Charging Current DF 0x3d−0x3e. Fast-Charging Current is stored in mA.
When fast charge terminates, the bq2085−V1P3 sets ChargingCurrent( ) to zero and then to the Maintenance
Charging Current DF 0x3f, 0x40 when the termination condition ceases. The desired maintenance current is
stored in mA.
When Voltage( ) is less than EDV0, the bq2085−V1P3 sets ChargingCurrent( ) to Precharge Current DF 0x41,
0x42. Typically this rate is larger than the maintenance rate to charge a deeply depleted pack up to the point
where it may be fast charged. The desired precharge rate is stored in mA.
If temperature is between 0° and the precharge threshold PC (°C), the bq2085−V1P3 sets ChargingCurrent( )
to PreCharge Current. The threshold is programmed in the Precharge Temp DF 0x43.
Precharge
Temp
+
PC (°C)
0.1
(10)
The bq2085−V1P3 also sets ChargingCurrent( ) to the precharge rate if Voltage( ) is less than the value
programmed in Precharge Voltage DF 0x3b−0x3c. Precharge Voltage is programmed in mV.
Charge Suspension
During charge, the bq2085−V1P3 compares the current to the ChargingCurrent( ) plus the value in OverCurrent
Margin DF 0x5c−0x5d. If the pack is charged at a current above or equal to the ChargingCurrent( ) plus the
programmed value, the bq2085−V1P3 sets ChargingCurrent( ) to zero to stop charging.
The desired Overcurrent Margin is programmed in mA.
The desired temperature threshold for charge suspension, MAXTEMP (°C), is programmed in Max
Temperature DF 0x53, 0x54 and is stored as shown:
Max Temperature +
MAXTEMP
0.1
(11)
The bq2085−V1P3 clears the maximum temperature condition when Temperature( ) drops by the amount
programmed in Temperature Hysteresis DF 0x55 from MAXTEMP or when the temperature is less than or equal
to 43.0°C. Temperature Hysteresis is stored in °C.
The bq2085−V1P3 suspends fast charge when fast charge continues past full by the amount programmed in
Maximum Overcharge DF 0x4e-0x4f. Maximum Overcharge is programmed in mAh.
FULLY_CHARGED Bit Clear Threshold
The bq2085−V1P3 clears the FULLY_CHARGED bit in BatteryStatus( ) when RelativeStateOfCharge( )
reaches the value, Fully Charged Clear % DF 0x47. Fully Charged Clear % is an 8-bit value and is stored in
percent.
Fast Charge Termination Percentage
The bq2085−V1P3 sets RM to a percentage of FCC on charge termination if the CSYNC bit is set in the gauge
configuration register. The percentage of FCC, FCT%, is stored in Fast Charge Termination % in DF 0x46. The
value is stored as shown:
45