STBC21 Datasheet, PDF (23/54 Pages) STMicroelectronics – LI+ battery charger with thermal regulation

STBC21
Detailed description
Battery alarm occurs when:
● TIMER-1 during pre-charge phase elapses;
● TIMER-4 during 0V-charge phase elapses;
● Overvoltage on the BAT pin occurs (V_BAT > 4.23 V ± 20 mV, infringement of JEITA/PSE
regulation);
● Undervoltage, during fast-charge or end of charge, on the BAT pin occurs (V_BAT < 3.0
V);
● Undervoltage on the TEMP pin occurs (V_TEMP < 0.505 V, battery overheating);
● Battery connection detection error occurs.
In all these cases the charge stops, the LEDs show a “Battery alarm” and a battery removal
is required to reset the charger. The battery removal is spotted because the voltage on the
TEMP pin rises above 2.425 V.
The battery alarm's flowchart is presented in Figure 13.
Charger alarm occurs when:
● Overvoltage on the V_CC pin occurs (V_CC > 9.0 V);
● Undervoltage on the V_CC pin occurs (V_CC < 2.8 V, except for the power-up transition
when the charger is switched on);
● Current increases over 1.1 A.
In these cases the charge is stopped, LEDs show a “charger alarm” and it's kept in this state
even if the battery is removed. A V_CC removal is required to reset the charger.
The charger alarm's flowchart is depicted in Figure 14.
Other alarms occur when:
● V_CC and V_BATT are very close (V_{CC_ASD} is lower than threshold);
● Die temperature increases over 115 °C (thermal shutdown).
In these cases the battery charge is stopped, the LEDs continue to show “charge ongoing” if
the charger was in charge, and “end of charge” if the charger was in the termination phase
and the timers keep on counting. Once the alarm condition is removed, the charger restarts
the operations restoring the status it was in before the interruption.
During this phase, all other alarms (battery alarms and charger alarms) are active.
Doc ID 023256 Rev 1
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