Keypad Back-Light Illumination - LG GW520 Service Manual

3.10 keypad back-light illumination

3.10.1 Qwerty keypad back-light illumination
There are 2 snow white color LEDs on Key for keypad illumination. Keypad Back-light is controlled by SM-
Power3 Flash LED port which has constant current control function. The whole configuration of the SM-
POWER3 Flash LED drivers is shown in below Figure.
VBAT
[Figure 3.10.1-2] Qwerty key back-light LED circuit diagram
Copyright © 2009 LG Electronics. Inc. All right reserved.
Only for training and service purposes
[Figure 3.10.1-1] LED driver in the SM-POWER3
EDLH0013701
R439
LD400
LEWWS44-E
R442
LD401
LEWWS44-E
R444
LD402
LEWWS44-E
R445
LD403
LEWWS44-E
3. BB Circuit Technical brief
GW520 service manual
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QWERTY_KEY_BL
LGE Internal Use Only