Lcd Back-Light Illumination - LG KF350 Service Manual

3. TECHNICAL BRIEF

3.9 LCD back-light illumination

The AS3675 is a highly-integrated CMOS Power and Lighting Management Unit for operating with
lithium-ion/polymer batteries. And AS3675 support 13 Current sinks, the RGB and white LEDs. The
AS3675 is capable of driving up to three LEDs at a total of 500mA. 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, 1.5X, or 2X mode, where the mode of operation is automatically selected by
comparing the forward voltage of each LED with the input voltage.
AUDIO_IN
1V8_CAM
C118
2.2u
PHOTO_ADC_IN
Figure 12 LCD Back light unit and Flash LED charge pump IC
LGE Internal Use Only
CHARGE PUMP
C111 1u
B1
AUDIO_IN
D2
LED1
RGB1
E2
LED2
RGB2
C2
LED3
RGB3
C1
LED4
CURR41
E1
LED5
CURR42
D1 U101
LED6
CURR43
AS3675
C117
1u
E6
V2_5
A2
VANA_GPI
A1
GPIO
- 44 -
B5
DCDC_GATE
C6
DCDC_SNS
D6
C112
DCDC_FB
1u
C4
VBAT
B4
C2_P
A3
C115
C2_N
A4
1u
C1_P
B3
C1_N
B2
VSS_CP
A5
CP_OUT
C5
CURR30 MLED1
D4
CURR31 MLED2
E3
CURR32 MLED3
D3
CURR33 MLED4
E5
CURR1 MLED5
D5
CURR2
E4
CURR6
B6
CLK SCL
A6
DATA SDA
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
VBAT
C113
1u
MLED
C116
2.2u