Feedback Circuit - BenQ G2220HD Product Service Manual

Feedback Circuit

R810
1M F
C808
0.01U K
PR827
C814
0.033U K R827
365 F
Fig.3 shows a feedback circuit consists of a lamp, R816, D805, R827 and C814. With the
lamp current through D805, a half sin-waveform voltage signal is produced. We may get the
Maximum value through R827 and C814.
After OZ9933 gets the feedback voltage signal from PIN14, the duty of the PWM driver
outputs is decided.
T801
.
5
1
.
2
C829
15P J
6
7
C830
3
15P J
4
.
8
1J.26051.041
PD806
D806
J
BAV70
Fig.3
- 63 -
F1
R831
C819 3M
5PF D
R819
100K
C820
470P J
R820
20K F
F3
C821
5PF D R832
3M
C821-2
R821
100K
C822
470P J
R822
20K F
A1 A2
D801
BAV70
R815
2.2K
C838 R841
0.1U 33K
R816
2.2K
D805
BAV99
K A
TP801
CN801
1
1
TP802
2
2
2K62272102
TP803
CN802
1
1
TP804
2
2
2K62272102