Pwpc Board; Block Diagram - Sony HS75 Service Manual

5.2 PWPC board

5.2.1 Block diagram

PWPC board combines to adapter and inverter, this design has the merits in predigesting
constructions, reducing cost and improving product's capability.
Adapter which commonly consists of bridge rectifier and filter, start circuit, PWM control circuit
(TOP247Y), 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, output circuit and protection circuit etc.
AC input
EMI filter
Royer –type L,C Resonance
circuit & Boost circuit
Lamp
Feedback
Circuit
Bridge
Rectifier
and Filter
Start Circuit
R906、R907
PWM
Control IC
Rectifier
Transformer
CMOS
MOSFET
Q903
Voltage
Feedback
Circuit
PWM convert &DC
Current Circuit
PWM
Control IC
30
HS75 Sony
Over
12V
Voltage
Protect
ON/OFF
ON/OFF
Control
BL ADJ
CN902
5V