LG GW520 - LCD Back-Light Illumination

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Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. BB Circuit Technical brief
GW520 service manual
3.11 LCD back-light illumination
SC654 is high efficiency charge pump LED driver using
.The load and supply conditions determine whether the charge pump operates 1X, 1.5X, or 2X mode.
[Figure 3.11-1] LCD charge pump circuit diagram
1u C805C804 1u
VA801
ICVL0518100Y500FR
4.7u
C803
C802
4.7u
ICVL0518100Y500FR
VA800
100K R805
SPIF
ICVL0518100Y500FR
VA802
SC654ULTRT
EUSY0369701
BL1
13
14
BL2
1
BL3
BL4
2
3
BL5
BL6
4
9
C1+
8
C1- C2+
10
C2-
7
6
GND
IN
12
OUT
11
5
U800
ICVL0518100Y500FR
VA803 VA804
ICVL0518100Y500FR
ICVL0518100Y500FR
VA805
MLED5
VBAT
MLED1
MLED2
MLED3
MLED4
MLED
LCD_BL_CTRL