Sylvania 6620LCT A - LCD Backlight Control Diagram

7-6
LCD Backlight Block Diagram
L3219BLIV
CURRENT CONTROL SWITCH
CURRENT CONTROL SWITCH
BACKLIGHT-SW
RL401
Q426
IC401 (DC-AC INVERTER CONTROL)
Q403
Q412
VCC
1 2
T450
CN450
LCD MODULE
INVERTER CBA
P-ON-H BACKLIGHT-ADJ
Q433
Q411
BACK LIGHT BACK LIGHT BACK LIGHT
26 27 23 24 28 14 11
9
13 12
1
16
+8V REG.
OUTPUT LOGIC1 OUTPUT LOGIC2
LOGIC
OVER VOLTAGE PROTECT
SLOW START
OSC
PWM2 PWM1
STANDBY MODE SW
4 5 7
OVER VOLTAGE PROTECTOR
Q451,452
OVER VOLTAGE PROTECTOR
Q454,455
7 6 98 1 2
13 14
T490
CN490
OVER VOLTAGE PROTECTOR
Q491,492
1 2
1 2
T460
CN460
OVER VOLTAGE PROTECTOR
Q461,462
10
IC402
(OP AMP)
TO SYSTEM CONTROL BLOCK DIAGRAM
AL+21V
9 7
3 1
6 4 2 5
10
8
9 7
3 1
6 4 2 5
10
8
9 7
3 1
6 4 2 5
10
8
TO POWER SUPPLY BLOCK DIAGRAM
MAIN CBA
AL+21V22
CN411
CLN411
AL+21V11 AL+21V33
CURRENT CONTROL SWITCH
Q421