LG U890 Service Manual page 47

3. TECHNICAL BRIEF
3.10.3.3. Charging control
A programmable charging block in PM6650-2 is used for battery charging. It is possible to set limits for
the charging current. The external supply typically connects directly to pin (VCHG). The voltage on this
pin (VCHG) is monitored by detection circuitry to ascertain whether a valid external supply is applied or
not. For additional accuracy or to capture variations over time, this voltage is routed internally to the
housekeeping ADC via the analog multiplexer. PM6650-2 circuits monitor voltages at VCHARGER and
ICHARGE pins to determine which supply should be used and when to switch between the two
supplies. These pins are connected to the Source (or emitter) and Drain (or collector) contacts of the
pass transistor respectively.
4.2V~3.81V
100~63 (%)
3.70V~3.62V
3.80V~3.71V
40~21 (%)
62~41 (%)
U890 Battery Bar Display
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3.49V~3.28V
3.61V~3.50V
2~0 (%)
20~3 (%)