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Start up Operation-3
< from AC plug in to
When the TV is plugged in, the rectifier start to produce DC voltage which leads
through PFC circuit directly to the power switches Q7301, Q7302. (PFC circuit
IC7201 does not operate at this moment.) Besides this DC voltage is provided also for
D7104, D7105 which provide start voltage to pin 1 of power supply IC 7301. When
the voltage on pin 1 rise up to predefined value IC7301 starts supplyinng of switching
pulses for Q7301, Q7302. Due to this current starts to lead through winding of T7301
which starts to generate output voltages. One of these voltages VCC is used for
power supplying of the IC 7301 to its pin 10.
When the power supply starts up, the 16V is providing by D7406,07/C7424. This
voltage leads to IC7405, which is 5 volts DCDC converter.
This voltage (STB5V) is provided to A board via connector P2 pin7. So if the TV is
plugged in, STB5V is provided to A board without trigger signal.
1
: P board >
<A+P>
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