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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 IREF & IMIN resistors.
IREF resistor between this pin and the GND pin to set the charge current limit determined by the
following equation:software debugging purpose.
ICC = 6820/33K = 207mA
The End Of Charging current is set by IMIN That can be programmed by the as following equation:
IEOC = 550/5.1K = 107mA
LGE Internal Use Only
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
CHARGING IC
DNI
R414
R420
5.1K
VDC_BYP
VUSB
2
4
_CHG
5
_EN
_PPR
3
ISL9221
U403
BAT
11
8
GND
6
IMIN
7
IUSB
9
IVDC
PGND
13
USB_BYP
10
1
VDC
12
C413
1u
R421
33K
C415
1u
VBAT
1u
C414
VBUS_USB
R415
100K
R498
DNI
VRTC_2V0
VIO_2V62
VCHG
R497
DNI
15K
R419
PPR
OVP_VUSB
OVP_VCHG
CHG_EN
CHG_EOC
Figure 26 USB charging circuit
Summary of Contents for KC550
Page 1: ...Date May 2008 Issue 1 0 Service Manual Model KC550 Service Manual KC550 Internal Use Only ...
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