8-7
LCD Backlight Block Diagram
A7121BLLB
CURRENT
CONTR
O
L
SWITCH
Q421
Q424
T401
CN401
LCD MODULE
BA
CK
LIGHT
BA
CK
LIGHT
O
VER V
O
LT
A
G
E
PR
O
TECT
OR
Q422
1
2
CN403
1
2
INV+22V
9
7
3
5
2
6
1
4
10
8
TO
PO
WER
SUPPL
Y
BLOCK
DIA
GRAM
MAIN CB
A
CURRENT
CONTR
O
L
SWITCH
Q461
Q464
T403
O
VER V
O
LT
A
G
E
PR
O
TECT
OR
Q462
9
7
3
5
2
6
1
4
10
8
O
VER V
O
LT
A
G
E
PR
O
TECT
OR
Q404
Q406
+10V REG.
O
VER CURERENT
PR
O
TECT
OR
Q425
Q405
SWITCHING
SWITCHING
SWITCHING
BA
CKLIGHT
-ADJ
Q401
SW+22V
T
O
SYSTEM
CONTR
OL
BLOCK
DIA
GRAM
SWITCHING
Q407
NOTE: CBA AND PWB MEANS PRINTED WIRING BOARD.