Keypad Back-Light Illumination; Lcd Back-Light Illumination; Only For Training And Service Purposes - LG KC780 Service Manual

3.10. Keypad back-light illumination

There are two kind of white LEDs on the Key FPCB and Key PCB for keypad illumination. Keypad
Back-light is controlled by GPIO port of the S-GOLDRADIO(KEY_BL) and by Backlight charge pump
IC(BD6095).
KEY BACKLIGHT
KEY_BL

3.11. LCD back-light illumination

Employed the BD6095 is a dual charge pump designed to support both the white LED backlight and flash
applications for systems operating with lithium-ion/polymer batteries. The backlight charge pump is
capable of driving up to five LEDs at a total of 65mA for backlight. The current sinks may be operated
individually or in parallel for driving higher current LEDs. To maximize power efficiency, the charge pump
operates in 1X, 1.33X, 1.5X, or 2X mode, where the mode of operation is automatically selected by
comparing the forward voltage of each LED with the input voltage.
Copyright © 2008 LG Electronics. Inc. All right reserved.

Only for training and service purposes

R709
0
C710
R711
1u
47
LD700
R714 12K
UPPER_KEY_BL
R715
C711
12K 1u
Figure 16 Slide Key PCB Back-light LEDs
LEWWS44-E
LEWWS44-E
Figure 17 Key FPCB Back-light LEDs
VBAT
R710
MLED
DNI
R712
47
LD701
R713
DNI
3
Q700
2
KTC4075E
1
R716 R717
10 10
LD600
R609
R610
LD601
- 45 -
3. TECHNICAL BRIEF
SUB_KEY_BL
VBAT
10
10
LGE Internal Use Only