
Pin Functions
OPTIMWATT
TM
STV9382
2/10
1
Pin Functions
2
Functional Description
The STV9382 is a vertical deflection circuit operating in Class D. Class D is a modulation method
where the output transistors work in switching mode at high frequency. The output signal is restored
by filtering the output square wave with an external LC filter. The major interest of this IC is the
comparatively low power dissipation in regards to traditional amplifiers operating in class AB,
eliminating the need of an heatsink.
Except for the output stage which uses Class D modulation, the circuit operation is similar to
the
one of a traditional linear vertical amplifier.
A (sawtooth) reference signal has to be applied to the circuit which can accept a differential or
single ended signal. This sawtooth is amplified and applied as a current to the deflection yoke. This
current is measured by means of a low value resistor. The resulting voltage is used as a feedback
signal to guarantee the conformity of the yoke current with the reference input signal.
The overvoltage necessary for a fast retrace is obtained with a chemical capacitor charged
at the
power supply voltage of the circuit. At the flyback moment, this capacitor is connected in series with
the output stage power supply. This method, used for several years with the linear vertical boosters
and called “internal flyback” or “flyback generator”, avoids the need of an additional power supply,
while reducing the flyback duration.
The circuit uses a BCD process that combines Bipolar, CMOS and DMOS devices. The output
stage is composed of low-R
ON
N-channel DMOS transistors.
Table 1: STV9382 Pin Descriptions
Pin
Name
Function
Pin
Name
Function
1
-V
CC
Negative Supply
11
SGND
Signal Ground
2
-V
CC
Negative Supply
12
IN-
Error Amplifier Inverting Input
3
-V
CC
Negative Supply
13
IN+
Error Amplifier Non-inverting Input
4
OUT
PWM Output
14
EA out
Error Amplifier Output
5
CFLY+
Flyback Capacitor
15
+V
CC
Positive Supply
6
CFLY-
Flyback Capacitor
16
+V
CC
POW
Positive Power Supply
7
BOOT
Bootstrap Capacitor
17
-VccPOW
Negative Power Supply
8
FEEDCAP1
Feed-back Integrating Capacitor
18
-V
CC
Negative Supply
9
FEEDCAP
Feed-back Integrating Capacitor
19
-V
CC
Negative Supply
10
FREQ
Frequency Setting Capacitor
20
-V
CC
Negative Supply