Gd Board - Sony FWD-32LX1R Service Manual

3-12. GD Board

DC-DC converter
The output voltage (13 V) of a main converter is output to D3.3 V using a step-down converter consisting
of IC7500, Q7501, L7502, and C7522 on the GD board. Similarly, A3.3 V is output from IC7500, Q7500,
L7501, and C7521. 5V is output from IC7600, Q7600, L7601, and C7621. D5 V is output from IC7600,
Q7601, L7602, and C7622. A3.3 V is output to CN7405 (1-3 pins) and CN7402 (3-5 pins), and D3.3 V is
output to CN7405 (6-8 pins) and CN7402 (9-11 pins). 5 V is output to CN7403 (1-3 pins), and D5 V is
output from CN7404 (8-9 pins) and CN7401. The DC-DC converter is turned on and off by setting the
POWER_ON signal (CN7203 (pin 9) on the G4 board, CN7202 (pin 3), and CN7501 (pin 3) on the GD
board) and PON-PANEL signal (at pin 7 of CN6404) from a microcomputer to high and low. A high-
level signal is first input from CN7501 (3 pins)(POWER_ON signal) to IC7500 (9-10 pins) and IC7600
(10 pins), and A5 V, A3.3 V, and D3.3 V are output. After two seconds, a high-level signal is input from
the PON-PANEL signal (CN7501 (6 pins)) from a microcomputer to IC7600 (9 pins) and a PNL_Vcc
signal is output.
Also, 13 V is converted into 5 V and 10.5 V for output using a chopper regulator (consisting of IC7400
and IC7401).
A5 V is output to CN7404 (4-5 pins) and 10.5 V is output to CN7404 (1 pin) and CN7401 (3 pin).
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FWD-32LX1R