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P
o
w
e
r
B
o
a
rd
+12V
IC 503
AP1506
U511
Standby
control circuit
INVERTER
BOARD
U506
+5VEXT
FOR PANEL
3.2.5 Power circuit
1. Power circuit block diagram
(1) Power circuit supplies stable and pure power for each unit circuit to ensure normal working of the
player. Power circuit block diagram is shown in the figure 3.2.5.1:
Figure 3.2.5.1 Power circuit block diagram
AP1506
5V
U507
Lm1085
MST718
U505
AMS1117
U521
Lm1085
U1
AMS1117
U513
+12V
U502
Si9435
+2.5V
MST718
+3.3V
Dv33
1.8V
STBY
3.3V
(2) Working principle: after AC power is being rectified and filtered through power board, 12V power
outputs. This power is inputted to voltage stabilizing circuit of video main board through socket Cn6 for
voltage stabilizing. The power outputted after being voltage stabilized is working power of each circuit.
Voltage stabilizing circuit on video main board is divided to 3 parts: 1) +5VEXT outputted after being
voltage stabilized by Ic503 is mainly supplied for system control circuit; 2) +5V power outputted after
being voltage stabilized by is mainly supplied for DVD/DVB circuit; 3) +12V voltage stabilizing and
control circuit supply working voltage for rear audio circuit.
(3) Introduction to each functional module in the picture: U502 is display screen power control pipe,
controlled by PANELON signal outputted by MST718; U511 is 12V power control pipe; U505/U507 is
voltage stabilizing IC, which supplies working power for MST718; U516/U1/U521 is voltage stabilizing
IC and voltage outputted after voltage stabilizing is supplied for DVD circuit. Please refer to the following
part “Principle analysis” for working principle.
2. +5VEXT
(1) +5VEXT
3.2.5.3:
Voltage stabilizing circuit and display screen Power control circuit
Voltage stabilizing circuit and display screen Power control circuit diagram is shown in
the figure
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