STMicroelectronics Confidential
5/14
STV8172A
Application Hints
4
Application Hints
The yoke can be coupled either in AC or DC.
4.1
DC-coupled Application
When DC coupled (see
Figure 4
), the display vertical position can be adjusted with input bias. On
the other hand, 2 supply sources (V
S
and -V
EE
) are required.
A Stand-by state will be reached by switching OFF the positive supply alone. In this state, where
both inputs are the same voltage as pin 2 or higher, the output will sink negligible current from the
deviation coil.
4.1.1
Application Hints
For calculations, treat the IC as an op-amp, where the feedback loop maintains V
1
= V
7
.
Figure 4: DC-coupled Application
R3
+Vs
R2
R1
Rd(*)
Yoke
Ly
Vertical Position
Adjustment
-V
EE
Vref
(*) recommended:
Ly
50
m
s
-------------
Rd
Ly
20
m
s
-------------
<
<
0.1μF
0.1μF
C
F
(47 to 100μF)
Power
Amplifier
Flyback
Generator
Thermal
Safety
470μF
470μF
Output
Current
Output
Voltage
I
p
7
3
2
5
6
1
4
V
M
V
m
+
-
0.
2
2
μ
F
1.5
W
