BQ2085-V1P3 Datasheet, PDF (18/57 Pages) Texas Instruments – SBS-COMPLIANT GAS GAUGE IC FOR USE WITH THE bq29311

bq2085-V1P3
SLUS598 − FEBRUARY 2004
www.ti.com
Table 10. bq2085−V1P3 to bq29311 Interface (FET Protection Control)
Battery State (Table 6)
CVOV = 1: Prolonged Overcurrent, Overvoltage, Overtemperature
CVOV = CVUV = 0
CVUV = 1: Overload, Overdischarged
(1) _{State determined by bq29311}
(2) _{On if there is a discharge current ≥ 50 mA}
(3) _{On if there is a charge current ≥50 mA.}
DISCHARGING FET
Normal ⁽¹⁾
Normal ⁽¹⁾
Off(3)
CHARGING FET
Off (2)
Normal ⁽¹⁾
Normal ⁽¹⁾
Table 11. Stand-Alone bq29311 Protection Control
MODE
CONDITION
Over Load
AFE Over Curr Dsg (DF 0xb2) is breached for Over Curr Delay (DF 0xb4)
Over Current
AFE Over Curr Chg (DF 0x0b3) is breached for Over Curr Delay (DF 0xb4)
Short Circuit, Discharge AFE Short Circ Thresh (DF 0xb6) is breached for AFE Short Circuit Delay
(DF 0xb7, lower nibble)
Short Circuit, Charge
AFE Short Circ Thresh (DF 0xb6) is breached for AFE Short Circuit Delay
(DF 0xb7, upper nibble)
(1) _{Clear is detected and controlled by the bq2085−V1P3.}
CLEAR(1)
AverageCurrent() = 0 mA
AverageCurrent() = 0 mA
Normal: AverageCurrent() = 0 mA
Sleep: Recovery delay of 20 s
Normal: AverageCurrent() = 0 mA
Sleep: Recovery delay of 20 s
SAFE Output
The SAFE output of the bq2085−V1P3 provides an additional level of safety control. The active low safety output
can blow a fuse or control another switch on the basis of temperature, a pack-voltage cell-voltage, or an integrity
check of the AFE registers.
The SAFE output is driven low in any of the following 4 conditions if the SAFE output activates, the
bq2085−V1P3 sets the SOV bit in pack status. SOV remains set until the bq2085−V1P3 is reset. The SAFE
output can be pulled high (cleared) by a POR of the bq2085−V1P3 only.
SAFE activation conditions:
D When CVOV = 1 AND after a minimum of 1s Voltage() > Safety Over Voltage (DF 0x68 and 0x69), or
D When CVOV = 1 AND after a minimum of 1s the Temperature() > Safety Temperature (DF 0x6a and 0x6b)
D When Miscellaneous Configuration (0x2a) bit 5 AC is set, and the AFE has failed at least AFE Fail Times
(DF 0xd3, d4)
The bq2085−V1P3 checks the programming of the AFE registers at a period determined by AFE Check Time
DF 0xe4. The units of the check period are seconds unless the bq2085−V1P3 is in sleep mode, in which case
the period is AFE Check Time x Sleep Current Time (DF 0xe7) If the data is not correct, the bq2085−V1P3
increments an internal counter.
The CVOV flag in PackStatus() (0x2f) is set in any of the following ways
D Voltage() = ChargingVoltage() + OverVoltageMargin (DF 0x5a, 0x5b)
D AverageCurrent() = FastCurrent + OvercurrentMargin (DF 0x5c, 0x5d)
D Any cell voltage = CellOverVoltage (DF 0x60, 0x61)
D The BatteryStatus() Over temperature bit is set
An example circuit using the SAFE output to blow a fuse is shown in Figure 5.
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