Power Supply Board Section - Panasonic KX-FT937LA-B Service Manual

6.12. 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 D10, D11, D12 and D13 and charges C5 to make DC voltage. Then it supplies power to the con-
verter circuit.
[Kick-on voltage circuit]
Bias is applied to the Q1 gate via this circuit when the AC power is turned on and Q1 begins operating.
Block Diagram
A
+
C5
R2
-
Kick-on
R3
B
Voltage
Circuit
R4
Converter
Circuit
C
Q1
Surge
absorber
D
circuit
E
Control
Circuit
O.C.L
F
Error Detecting
Circuit
45
KX-FT937LA-B
G
24V
24V
Output
Circuit
Over
voltage
GND
9~6V
6V
Output
Circuit
H