Kyocera Mita DC-2060, Service Manual

Page: 106 / 437

1AH
2-3-1
2-3-1 Composite PCB
(1) Power source section
AC
input
Switching control/
overcurrent
detection circuit
TRNS
24 V DC
output
5 V DC
output
5 V DC
output
circuit
FET
Q102
24 V DC
output/
error
detection
circuit
PC2
MSW
PC1
Noise filter
circuit 2
Noise filter
circuit 1
Rectifier
/active
filter
circuit
Overvoltage
detection
circuit
Figure 2-3-1 Power source section block diagram
Power source section of the composite PCB (CPCB) consists of the circuit shown in
Figure 2-3-1 to generate from the AC input into stable 24 V and 5 V DC output.
In the power source circuit, the AC input is converted into DC voltage, after it is
stabilized in the active filter circuit, and the DC voltage is converted to the pulse
waveform switching with FET (Q102).
The pulse waveform is applied to the primary side of transformer (TRNS), the pulse
waveform induced on the secondary side is rectified and smoothed into a 24 V DC
output.
5 V DC output is obtained by step-down 24 V DC output with the switching regulator.