Usb Charging Circuit - LG KE600 - Cell Phone Service Manual

3. TECHNICAL BRIEF

3.14. USB charging circuit

The USB charging circuit is a fully integrated USB VBUS voltage single-cell Li-ion battery charger
circuit. The charger uses a CC/CV charge profile required by Li-ion batteries. CC charging current and
End of charging current is programmable I
I resistor between this pin and the GND pin to set the charge current limit determined by the
REF
following equation:
I = 12089/33K = 366mA
CC
The End Of Charging current is set by I
I = 11000/220K = 50mA
EOC
2V72_IO
R250
10K
USB_EOCn
USB_CHG_ENn
& IMIN resistors.
REF
That can be programmed by the as following equation:
MIN
VBUS_USB
TP217
R221 0
R216 0
C242
R251
1u
NA
Figure 26 USB charging circuit
- 52 -
U205 ISL6294
1 8
VIN BAT
2 7
_PPR IREF
3 6
_CHG IMIN
4 5
_EN GND
9
PGND
VBAT
C243
1u