Changhong Electric 34T18, Руководство по обслуживанию, Страница: 38 / 61

SERVICE MANUAL
36
1.8 Vertical deflection output TDA8359J
(1) Introduction
The TDA8359J is an integrated power circuit for use in 90° and 110° colour deflection systems. It
contains a vertical deflection bridge output, operating as a high efficiency class G system and can
handle field frequencies from 25 to 200 Hz. The vertical coil of a 4 : 3 as well a 16 : 9 picture tube
can be connected to this vertical deflection device. Due to the bridge configuration a DC deflection
output application can be designed with a positive main supply of typical 12 Volts and a positive
flyback supply of typical 45 Volt. (Depending on the coil data).
This integrated circuit is designed in a Low Voltage DMOS (LVDMOS) process that combines
bipolar, CMOS and DMOS components. DMOS output transistors (MOSFETs) are used because of
the absence of secondary breakdown, which gives a better SOAR performance. The internal circuits
are designed in such way that only a few external components are needed to get a correct working
application.
The TDA8359J is functional the same as the TDA8357J vertical deflection output stage. The
TDA8359J differs in only one aspect from the TDA8357J, it is able to deliver a higher output current
which is more suitable for large picture tubes.
A detailed investigation procedure to determine an optimum application is given at the end of this
report.
(2) Features
· Few external components required
· High efficiency fully DC coupled vertical bridge output circuit
· Short rise and fall time of the vertical flyback switch
· Picture tube burn in protection signal (guard circuit)
· Temperature (thermal) protection circuit
· Differential mode inputs
· Blanking pulse generator (guard)
· Improved EMC performance due to differential inputs
(3) Pinning
Table 10
Symbol Pin Description
INA 1 Input A
INB 2 Input B
VP 3 Supply voltage
OUTB 4 Output B
GND 5 Ground
VFB 6 Flyback supply voltage
OUTA 7 Output A
GUARD 8 Guard output
FEEDB 9 Feedback input
2
3
4
5
6
7
8
9
TDA8359J
INA
INB
V
P
OUTB
GND
VFB
OUTA
GUARD
FEEDB
Fig. 20