Pwpc Board Block Function Description - ViewSonic VX2262WM - 22" LCD Monitor Service Manual

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 16V, 5V,5.1V 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 16v 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
OSC and
Output
Circuit
Lamp
Feedback
Circuit
ViewSonic Corporation
Bridge
Rectifier
and Filter
Start Circuit
R904, R905, R906
PWM
Control IC
DC Convert
Circuit
Over
Voltage
Transformer
MOSFET
Q804,Q809
PWM
Control IC
- 18 –
Confidential - Do Not Cop
Rectifier
CMOS
Over
Voltage
Protect
16V
ON/OFF
Control
DIM
VX2262wm/wmp
CN902
5V
5.1V
ON/OF