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ViewSonic Corporation
Confidential - Do Not Cop
VP950b
4.3 PWPC BOARD BLOCK FUNCTION DESCRIPTION
PWPC board combines to adapter and inverter, Adapter which commonly consists
of bridge rectifier and filter, start circuit, PWM control circuit, protection circuits and
convert to 12V, 5V DC voltage by input 90V-240V AC voltage that provide power supply
for each chips in the main board and inverter. Inverter is DC TO AC circuit. It changes
the 12v DC of power supply to about 600-800v AC that drives the backlight. It mostly
consists of starting circuit, PWM controller, DC changing circuit, LC surging circuit,
output circuit and protection circuit etc.
AC input
EMI filter
Bridge
Rectifier
and Filter
Start Circuit
R905
PWM
Control IC
Over
Voltage
Protect
Rectifier
CMOS
ON/OFF
Control
PWM
Control IC
Feedback
Circuit
OSC and
Output
Circuit
DC Convert
Circuit
MOSFET
Q804
,
Q809
Over
Voltage
CN902
Transformer
Lamp
5V
12V
ON/OF
DIM
Summary of Contents for VP950B - 19" LCD Monitor
Page 25: ... 25 ViewSonic Corporation Confidential Do Not Cop VP950b Block Diagram ...
Page 39: ... 39 ViewSonic Corporation Confidential Do Not Cop VP950b ...
Page 41: ... 41 ViewSonic Corporation Confidential Do Not Cop VP950b ...
Page 48: ... 48 ViewSonic Corporation Confidential Do Not Cop VP950b 5 9 Packing Procedure ...
Page 49: ... 49 ViewSonic Corporation Confidential Do Not Cop VP950b 6 Troubleshooting Flow Chart ...
Page 68: ... 68 ViewSonic Corporation Confidential Do Not Cop VP950b Packing For Shipping ...
Page 83: ... 83 ViewSonic Corporation Confidential Do Not Cop VP950b 12 2 MAIN BOARD PCB BUTTON VIEW ...
Page 84: ... 84 ViewSonic Corporation Confidential Do Not Cop VP950b 12 3 POWER PCB TOP VIEW ...
Page 85: ... 85 ViewSonic Corporation Confidential Do Not Cop VP950b 12 4 POWER PCB BUTTON VIEW ...