LG -P990 Service Manual page 51

3. TECHNICAL BRIEF
Battery Voltage Regulation (CV Mode)
The battery voltage regulation feedback is through BATT pin. The RT954 monitors the battery valrage vetween
BATT and GND pins. When the battery voltage closes to battery regulation voltage threshold, the voltage
regulation phase begins and the charging current falls below the programmed end-of-charge current threshold,
the CHG_S pin gose high to indicate the termination of charge cycle.
The end-of-charge cyrrent threshold is set by the IEOC pin. The resistor R is connected to IEOC and GND.
ieoc
The parameters K and IEOC are specified in the specification table.
ieoc
RIEOC
I EOC (%) =
00
The current threshold of IEOC (%) is defined as the percentage of fast-charge current set by R . After the CHGSB
iset
pin pulled to high, the RT954 still monitors the vattery voltage. Charge current is resymed when the battery
voltagr goes to lower then the battery regulation voltage threshold.
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