BQ2085-V1P3 Datasheet, PDF (16/57 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085-V1P3
SLUS598 − FEBRUARY 2004
www.ti.com
Table 6. Alarm and Status Bit Summary (Continued)
BATTERY STATE
CONDITIONS
CC( ) CURRENT AND
STATUS BITS SET
STATUS CLEAR CONDITION
Primary Charge
Termination
Current taper
FC = 1, TCA = 1
CC( ) = Maintenance
Charging Current
RSOC( ) < Fully Charged Clear%
Fully Discharged
RM( ) < Battery Low % and
DISCHARGING = 1
FD = 1
RSOC( ) ≥ 20%
Overdischarged
Low Capacity
RM( ) = 0
V( ) ≤ Terminate Voltage
VCELL1, 2, 3 or 4 ≤ Cell Under Voltage
RM( ) < RCA( )
TDA = 1
TDA = 1, CVUV = 1
RCA = 1
V( ) > Terminate Voltage and RM( ) > 0
V( ) > Terminate Voltage
VCELL(all) ≥ Cell Under Voltage Reset
RM( ) ≥ RCA( )
Low Run Time
ATTE( ) < RTA( )
RTA = 1
ATTE( ) ≥ RTA( )
NOTE: AC( ) = AverageCurrent( ), C( ) = Current( ), CV( ) = ChargingVoltage( ), CC( ) = ChargingCurrent( ), V( ) = Voltage( ),
T( ) = Temperature( ), TCA = TERMINATE_CHARGE_ALARM, OTA = OVER_TEMPERATURE_ALARM,
OCA = OVER_CHARGED_ALARM, TDA = TERMINATE_DISCHARGE_ALARM, FC = FULLY_CHARGED,
FD = FULLY_DISCHARGED, RSOC( ) = RelativeStateOfCharge( ). RM( ) = RemainingCapacity( ),
RCA = REMAINING_CAPACITY_ALARM, RTA = REMAINING_TIME_ALARM, ATTE( ) = AverageTimeToEmpty( ),
RTA( ) = RemainingTimeAlarm( ), RCA( ) = RemainingCapacityAlarm( ). LTF = Low Temperature Fault threshold
FCC( ) = Full Charge Capacity
Cell Balancing
The bq2085−V1P3 balances the cells during charge by discharging those cells above the threshold set in Cell
Balance Threshold DF 0xd7−0xd8, if the maximum difference in cell voltages exceeds the value programmed
in Cell Balance Min DF 0xdb. For cell balancing, the bq2085−V1P3 measures the cell voltages at an interval
set in Cell Balance Interval DF 0xdc. On the basis of the cell voltages, the bq2085−V1P3 either selects the
appropriate cell to discharge or adjusts the cell balance threshold up by the value programmed in Cell Balance
Window 0xd9−0xda when all cells exceed the cell balance threshold or the highest cell exceeds the cell balance
threshold by the cell balance window.
The cell balance threshold is reset to the value in Cell Balance Threshold at the start of every charge cycle.
The threshold can be adjusted no more than once during a balance interval.
DISPLAY PORT
General
The display port drives a 3-, 4-, or 5-LED bar-graph display. The display is activated by a logic signal on the
DISP input. The bq2085−V1P3 can display RM in either a relative or absolute mode with each LED representing
a percentage of the full-battery reference. In relative mode, the bq2085−V1P3 uses FCC as the full-battery
reference; in absolute mode, it uses Design Capacity (DC).
The DMODE bit in Pack Configuration DF 0x28 programs the bq2085−V1P3 for the absolute or relative display
mode. The LED bits program the 3-, 4-, or 5-LED option.
Activation
The display may be activated at any time by a high-to-low transition on the DISP input. This is usually
accomplished with a pullup resistor and a pushbutton switch. Detection of the transition activates the display
and starts a four second display timer. Reactivation of the display requires that the DISP input return to a
logic-high state and then transition low again. The second high-to-low transition can be detected only after the
display timer expires. If unused, the DISP input must be pulled up to V_CC.
If the EDV0 bit is set, the bq2085−V1P3 disables the LED display.
Display Modes
In relative mode, each LED output represents 20%, 25%, or 33% of the RelativeStateOfCharge( ) value. In
absolute mode, each LED output represents 20%, 25% or 33% of the AbsoluteStateOfCharge( ) value. Table 7
shows the display options for 5 LEDs Table 8 for 4 LEDs, and Table 9 for 3 LEDs.
In either mode, the bq2085−V1P3 blinks the LED display if RemainingCapacity( ) is less than Remaining
CapacityAlarm( ). The display is disabled if EDV0 = 1.
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