Technicolor - Thomson ICC19, Principles And Maintenance

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IC001, STV2151
POWER SUPPLY
9VREG is the IC001 power source. Through a regulator built into IC001 and
power Transistor TC001, it powers the IC001 (Pin 18) with a typical voltage
of 7.7 V. Resistor RC007 sets the reference current required for this
regulation.
Diode DC001 brings this voltage down to a typical value of 7 V, which powers
the internal logic circuits of the IC001.
A reference voltage value of 3.85 V typical (VCC/2) is obtained from the
regulation stage.
IDENTIFICATION
During a colour standard search phase, IC001 is configured in PAL, SECAM,
and then NTSC successively, until the standard is identified (four frames
each).
The SECAM colour standard is identified by the frequency demodulation of
the subcarrier bursts.
The PAL/NTSC colour standards are identified by the amplitude
demodulation of the bursts.
The dc voltages obtained are memorised in Capacitors CC002 and CC003
(Pins 23 and 25), and supply the identification criteria.
CENTRE DE
FORMATION TECHNIQUE
93
93
25 IC01
ID1 ( B )
3.8V
4.85V
5.15V
5.25V
23 IC01
ID3 (+R )
STANDARD
NO BURSTS
PAL
SECAM
NTSC
3.8V
2.75V
2.85V
3.75V