Power Supply Board Section - Panasonic KX-FP81BX Service Manual

6.13. POWER SUPPLY BOARD SECTION

This power supply board uses the switching regulator method.
AC
Input
Input
Rectifier
Circuit
Circuit
A-B Voltage Wave Form
0
C-D Voltage Wave Form
0
E-F
G-H Voltage Wave Form
0
[Input Circuit]
The input current goes into the input rectifier circuit through the filter circuit. The filter circuit decreases the noise voltage and
the noise electric field strength.
[Rectifier Circuit]
The input current is rectified by D101,D102,D103 and D104 and charges C106 to make DC voltage. Then it supplies power to
the converter circuit.
[Kick-on voltage circuit]
Bias is applied to the Q101 gate via this circuit when the AC power is turned on and Q101 begins operating.
Block Diagram
A
+
C106
R136
-
Kick-on
R137
B
Voltage
Circuit
Surge
absorber
Converter circuit
Circuit
C
Q101
Surge
absorber
D
circuit
Control
Circuit
E
IC101
• O.C.L
• Over voltage
F
Error Detecting
Circuit
171
KX-FP81BX / KX-FP81CX / KX-FP82CX
G
24V
24V
Output
Circuit
GND
5V
5V
Output
Circuit
H