Battery Removal During Charging - Nokia Mobile Phones NSE-5 Series Service Manual

PAMS
Technical Documentation
VCH
VCH<VOUT
VOUT
VLIM1 or VLIM2
SWITCH
PWM (32Hz)

Battery Removal During Charging

Output overvoltage protection is also needed in case the main battery is
removed when charger connected or charger is connected before the
battery is connected to the phone.
With a charger connected, if VOUT exceeds VLIM1 (or VLIM2), CHAPS
turns switch OFF until the charger input has sunken below Vpor (nominal
3.0V, maximum 3.4V). MCU software will stop the charging (turn off PWM)
when it detects that battery has been removed. The CHAPS remains in
protection state as long as PWM stays HIGH after the output overvoltage
situation has occured.
Issue 1 07/99
ON OFF ON
NSE–5
System Module
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