TCL 21M63S-NX56E - AC-Coupled Applications

STMicroelectronics Confidential 7/14
STV8172A Application Hints
4.2 AC-Coupled Applications
In AC-coupled applications (See Figure 6), only one supply (V
S
) is needed. The vertical position of
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).
4.2.1 Application Hints
Gain is defined as in the previous case:
Choose R
1
then either R
2
or R
3
. For good output centering, V
7
must fulfill the following equation:
or
Figure 6: AC-coupled Application
R
3
+Vs
R
2
R
1
Rd(*)
Yoke
Ly
(*) recommended:
Ly
50ms
------------- R d
Ly
20ms
-------------<<
0.1µF
C
F
(47 to 100µF)
Power
Amplifier
Flyback
Generator
Thermal
Safety
470µF
Output
Current
Output
Voltage
I
p
7
32
5
6
1
4
V
M
V
m
+
-
C
s
R
4
C
L
R
5
0.22µF
1.5W
I
p
V
M
V
m
–
2
------------------------
R
2
R
1
R
3
´
--------------------- -
´=
V
S
2
--------V
7
–
R
4
R
5
+
----------------------
V
7
V
M
V
m
+
2
------------------------–
R
3
--------------------------------------
V
7
R
2
-------+=
V
7
1
R
3
-------
è
æ
1
R
2
-------+´
1
R
4
R
5
+
----------------------
ø
ö
V
S
2R
4
R
5
+()
------------------------------
V
M
V
m
+
2R
3
´
------------------------+
èø
ç÷
æö
=+