Panasonic TH-37PX60U, Technical Manual

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P15V/P5V Circuit
The P15V is generated when the power is turned on. The high (3.2V) “Panel Main On” command from the
D board is applied to pin 24 of the Power MCU (IC501) on the Power Supply board. When IC501 receives
this command on pin 24 (3.2V), pin 10 goes high (4.8V).
When the power on command is received, the F_STB_ON command (3.2V) is applied to pin 23 of IC501.
When pin 23 goes high, just like during standby, the relays are closed, the PFC circuit is on, and pin 15
goes high to turn on the low voltage power control (IC520) to drive the oscillator circuit (Q408, Q409,
Q412, and Q413).
When this happens, voltages are developed by the secondary circuit.
The rectified 15V from T404, is applied to the DC-DC converter (Q555).
The output of Q555 is controlled by the voltage on pin 4.
The high from pin 10 changes the bias of Q569 to provide 22V to pin 4 of Q555, turning it on. When Q555
is on, 15V is output on pins 1, 2, and 3. This voltage is applied to the 5V DC-DC converter (IC510) to
output the P5V.
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