STBC21 Datasheet, PDF (20/54 Pages) STMicroelectronics – LI+ battery charger with thermal regulation

Detailed description
STBC21
Figure 9. Battery temperature alarm during charge flowchart
BaƩery Temperature
Alarm DetecƟon /
During charge
YES
BaƩery Temperature >
60°C
NO
YES
BaƩery Temperature < -
2°C
NO
Charge on going
NO
LED SET
Charge
0°C < BaƩery Temperature < 43°C
YES
Charge on going
LED SET
BaƩery Temperature
Alarm occurrence
Stop charging
Timers keep counƟng
BaƩery Temp Alarm /
During charge
LED SET
NO
BaƩery Temperature
> 60°C
YES
Increase
alarm counter
NO
Alarm asserƟons =2 Ɵmes
YES
Charging CompleƟon
LED SET
Restart charging from the
interrupted point
BaƩery
NO
removed
YES
BaƩery UnistallaƟon
LED SET
AM10420v 1
END
The chip also includes an NVM to allow the temperature thresholds above to be
programmable few times by the battery manufacturer.
The temperature thresholds are sensed by the NTC inside the battery pack. A reference
voltage is properly partitioned to translate the variable resistance in a variable voltage as
shown in Figure 10.
Figure 10. Temperature detector schematic
VREF
R₁
R₃
NTC R₂
R_PART2
+
TEMP
R_PART1
_
20/54
BATTERY PACK
Doc ID 023256 Rev 1
STBC21
AM10421v 1