Charging Circuit - LG KF350 Service Manual

3. TECHNICAL BRIEF
3.12.2 Microphone circuit
MAIN_MIC_P
MAIN_MIC_N
MAIN_MIC_N

3.13 Charging circuit

ISL9221 accepts two power inputs, normally one from a USB (Universal Serial Bus) port and the other
from a desktop cradle.
The ISL9221 features 28V and 7V maximum voltages for the cradle and the USB inputs respectively.
Due to the 28V rating for the cradle input, low-cost, large output tolerance adapters can be used
safely.
_EOC
CHG_EN
LGE Internal Use Only
VMIC_P
Figure 18 Microphone circuit
2V62_VIO 2V62_VIO VUSB_USB
VCHG
R222
100K
_PPR C257
1u
Figure 19 Charging circuit
MIC100
1
OUT
2
G1
3
G2
4
G3
5
PWR
6
G4
SPM0204LE5-QB
U204 ISL9221
13
PGND
1
VDC
12
VDC_BYP
2
VUSB
11
BAT
3
_PPR
10
USB_BYP
4
_CHG
9
IVDC
5
_EN
8
GND
6
IMIN
7
IUSB
R223
10K
(1%)
Copyright © 2008 LG Electronics. Inc. All right reserved.
- 48 -
VBAT
OVP_VCHG
OVP_VUSB
R225 R224
C256
18K 16K
1u
(1%) (1%)
Only for training and service purposes