BenQ MP611 - Feedback Circuit and Photo Coupler; Secondary Rectifier and Filter

148
5.8 Feedback circuit and photo coupler
1206F
0805F
1206J
0805
0805F
R
K
A
3
4
2
1
0805J
+
R753
R751
R750
C751
R754IC750
IC652
R706
C750
1%
1.2K
1%2.87K
360
50V
0.1U
1%
10KTL431
PC123
1K
105C
50V
22U
(EL)
12V
2.5V
The power supply adapt a single feedback circuit of 12V. It used IC750 for voltage regulation and
IC652 for primary-secondary isolation. The output voltage will be controlled by IC750 pin 1 (feedback) ,the
duty cycle of MOSFET will be decided to control the output voltage.
5.9 Secondary rectifier and filter
+
D703
C709
T651
2.5V
GND
Since the transformer T651 acts as a storing energy inductance , Diode D703 is rectifier and
capacitor C709 is to reduce the output ripple and noise.