Service manual

26
7.2)TDA 8357
GENERAL DESCRIPTION
The TDA8357J is a power circuit for use in 90° and
110° colour deflection systems for 25 to 200 Hz field
frequencies, and for 4 : 3 and 16 : 9 picture tubes. The IC
contains a vertical deflection output circuit, operating as a
high efficiency class G system. The full bridge output
circuit allows DC coupling of the deflection coil in
combination with single positive supply voltages.
The IC is constructed in a Low Voltage DMOS (LVDMOS)
process that combines bipolar, CMOS and DMOS
devices. DMOS transistors are used in the output stage
because of absence of second breakdown.
FEATURES
• Few external components required
• High efficiency fully DC coupled vertical bridge outputcircuit
• Vertical flyback switch with short rise and fall times
• Built-in guard circuit
• Thermal protection circuit
• Improved EMC performance due to differential inputs
SYMBOL PARAMETERS CONDITIONS MIN. TYP. MAX UNIT
Vp Supply voltage 7.5 12 18 V
VFB flyback supply voltage 2 x VP 45 66 V
Iq(P)(av) average quiescent supply current during scan - 10 15 mA
Iq(FB)(av) Iq(FB)(av) during scan - - 10 mA
Ptot total power dissipation - - 8 W
Vi(p-p) input voltage (peak-to-peak value) - 1000 1500 mV
Io(p-p) output current (peak-to-peak value) - - 2.0 A
Io(peak) maximum (peak) output current
t ≤ 1.5 ms
--± 1.2A
Tstg storage temperature -55 - +150
ºC
Tj junction temperature - - +150
ºC
Supplies
Inputs and outputs
Flyback switch
Thermal data; in accordance with IEC 60747-1
7.3)MC14052B
The MC14052B analog multiplexer is a digitally–controlled analog switch.
The MC14052B effectively implements a DP4T solid state switch. This
device’s feature low ON impedance and very low OFF leakage current.
Control of analog signals up to the complete supply voltage range can be
achieved.
• Triple Diode Protection on Control Inputs
• Switch Function is Break Before Make
• Supply Voltage Range = 3.0 Vdc to 18 Vdc