Qls 21M62US (CHASSIS: NX56-LA) Service Manual page 57

STV8172A
4.2 AC-Coupled Applications
In AC-coupled applications (See
the scanning cannot be adjusted with input bias (for that purpose, usually some current is injected
or sunk with a resistor in the low side of the yoke).
470μF
R
3
V
M
V
m
(*) recommended:
4.2.1 Application Hints
Gain is defined as in the previous case:
Choose R then either R
1
or
Figure 6), only one supply (V
Figure 6: AC-coupled Application
C (47 to 100μF)
F
0.1μF
6
Power
Amplifier
7
+
1
-
Thermal
4
Ly Ly
------------ - < Rd < -------------
50ms 20ms
V
M
= ----------------------- -
I p
or R . For good output centering, V
2 3
V
S
–
------- - V 7 V
2
--------------------- - = ------------------------------------- -
R 4 + R 5
æ 1 --------------------- - ø ö
1 1
´
V 7 ------- + ------- +
è
R 2
R 3 R 4 + R 5
) is needed. The vertical position of
S
3 2
Flyback
Generator
Safety
R
5
–
V R
m 2
´
--------------------- -
´
2 R 1 R 3
must fulfill the following equation:
7
V + V
M m
–
------------------------
V
7
2 7
+ -------
R 3 R 2
V V
æ
S M
ç
= ------------------------------ + ------------------------
( ) ´
2 R 4 + R 5 2
è
STMicroelectronics Confidential
Application Hints
+Vs
Output
Voltage
Output
Current
5
1.5W
Rd(*)
R
C 4
s
C
L
R
2
R
1
+ V
ö
m
÷
R 3
ø
I
p
Yoke
Ly
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