STV9302A
Application Hints
4.2
AC-Coupled Applications
In AC-coupled applications (See Figure 6), only one supply (V ) is needed. The vertical position of
S
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).
Figure 6: AC-coupled Application
+Vs
Output
Voltage
CF (47 to 100µF)
3
470µF
0.1µF
6
2
Output
Current
Flyback
Generator
Ip
Power
Amplifier
7
1
+
5
-
Yoke
Ly
Thermal
Safety
R3
1.5Ω
Rd(*)
VM
Vm
4
R5
R4
Cs
CL
R1
Ly
50µs
Ly
20µs
R2
(*) recommended:
------------- < R d < -------------
4.2.1 Application Hints
Gain is defined as in the previous case:
V
– V
R
M
m
2
----------------------- ---------------------
I
=
×
p
2
R × R
1
3
Choose R then either R or R . For good output centering, V must fulfill the following equation:
1
2
3
7
V
V
+ V
S
M
m
V –
------- – V
------------------------
V
7
7
2
2
7
--------------------- = -------------------------------------- + -------
R + R
4
R
R
5
3
2
or
V
V
+ V
ꢀ
ꢀ
ÿ
ꢀ
m
1
R
2
S
M
1
1
ꢀ
ÿ
ꢀ
þ
V ×
+ ------- +
=
------------------------------ + ------------------------
-------
R
---------------------
R + R
ꢀ
7
2(R + R )
2 × R
þ
3
4
5
3
4
5
7/15
STMICROELECTRONICS [ ST ]
