Keypad Back-Light Illumination; Lcd Illumination - LG L1150 Service Manual

3.3.13. Keypad back-light Illumination

There are 12 Deep Blue LEDs in Main Board for Keypad Backlight.
Keypad Back-light is driven by 'LEDB' line from IOTA .

3.3.14. LCD Illumination

There are 4 LEDs in the LCD module for LCD backlighting.
(3LEDs for main LCD and 1 LED for sub LCD)
LCD_BACKLIGHT
Figure 19. Keypad Back-light Scheme
VBAT
R422
LEDB
20
R423
VA402
20
AVL5M02-200
Figure 20. LCD Back-light(Charge Pump) Scheme
VBAT
VA707
AVL5M02-200
N.A
- 37 -
3. H/W Circuit Description
KEY BACKLIGHT
CHARGE PUMP
U701 AAT3132ITP-T1
10 4
IN C1+
C741
1uF
3
C1-
1
C2+
2
OUT C744
1uF
12
C2-
9 8
EN_SET D1
6
D2
5
D3
11 7
GND D4
C746
39p
MLED
SLED
C747
39p