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TDA9103-USER

TDA9103 USER’S MANUAL DEMONSTRATION BOARD

STMicroelectronics 

TDA9103

USER’S MANUAL

DEMONSTRATION BOARD

I - INTRODUCTION

This demonstationboard has beenrealized in order

to provide the user with a complete and simple

evaluation tool of the deflection processor for mul-

tisync monitor TDA9103 (and possibly of the verti-

cal booster TDA8172).

This demoboard is in fact the core of a monitor

chassis. To have a complete monitor, we have only

to add a command board (microprocessor + key-

board), a line power board (EHT, S-correction, de-

flection transistor), a SMPS board and a video

board.

Besides the TDA9103 described in a separate data

sheet, we will find on this board the following func-

tions :

- A vertical deflection circuit based on the TDA8172

- A class A power amplifier for the EW correction

- A line transistor driver stage

- A DC/DC converter for the scanning supply (so

called B+)

- A separable analog command board with poten-

tiometers for the generation (from an external 5V

power supply) of the 11 control voltages required

by the TDA9103 and with a simulator of horizontal

flyback

In this way, the user will be able in a first step to

evaluate the performances of the IC under clean

conditions. In a second step, after having broken

the printed board, he will be able to connect the

demoboard to a monitor and to use the commands

of an existing monitor and thus use his own soft-

ware to drive the TDA9103.

II - TECHNICAL INFORMATIONS

II.1 - Board Description

II.1.1 - Main Board

II.1.1.1 - Core

The board is built around the IC TDA9103 and very

few external components :

- C2-R32

Line oscillator.

- C3-C7-R31 Filter of the line PLL.

- C4

Vertical oscillator.

- C5

Memory capacitor for the

vertical AGC.

- C26-R68-R67 Gain of the error amplifier

of DC/DC converter.

- D4-R80-C48

Circuit for improvement

behaviour with Composite Sync

(See Section II.1.1.8. These

components may be omitted

if such standards are not used).

II.1.1.2 - 0/5V to 2/6V Interface

The IC TDA9103 uses two 8V internal voltage

references VREF (for the vertical part) and HREF (for

the horizontal one). So, the analog voltage range is

2 to 6V.

As a microprocessor usually delivers a voltage in

the range 0-5V, we must implement an interface

with 3 resistors for each of the 10 adjustments

required by the TDA9103 (R1 to R30).

The four circuits for horizontal (resp vertical) adjust-

ments are connected to HREF (resp VREF).

II.1.1.3 - EW Amplifier

The parabola generated by the TDA9103 for the

EW correction must be amplified in order to drive

the diode modulator.

This function is performed by the class A amplifier

Q3-Q4-Q9. A DC voltage is added to the parabola

to achieve the horizontal size adjustments.

For a proper working, this amplifier must be loaded

(100Ω connected to Vp = 24V).

II.1.1.4 - Horizontal Line Driver Stage

The HOUT pulse delivered by the TDA9103 is used

to turn on a MOS transistor via a push pull stage.

The pulse is transmitted to the line transistor by a

driver transformer. When Q2 is ON (HOUT at high

level), the line transistor is off.

You will find in annexe the specification of the

transformer used on this board. Two key points of

the spec must be highlighted :

- Leakage inductor ≤2µH (this data set the turnoff

time of the power transistor).

- Parasitic capacitor < 50pf (a too high value leads

to a transmission of a commutation spike to the

secondary side and the chassisground and could

make some trouble in the working of the chassis).

April 1995

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