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Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
3. Technical Brief
3.9. Keypad back-light illumination
There are 2 snow white color LEDs on Key FPCB for keypad illumination. Keypad Back-light is controlled by
SM-Power Flash LED port which has constant current control function. The whole configuration of the
SM-POWER Flash LED drivers is shown in below Figure11.
Figure 12. Keypad Back-light LEDs
VBAT
R100
47ohms
47ohms
R101
R
F
0
5
1
X
5
0
5
0
N
V
CI
0
0
1
A
V
LEWWS44-E
LD101
1
2
4
0
1
A
V
R
F
0
5
1
X
5
0
5
0
N
V
CI
LEWWS44-E
LD100
1
2
KEY_BACKLIGHT