Kyocera Mita DC-2060, Service Manual

Page: 110 / 437

1AH
2-3-5
d. 24 V DC output (smoothing)/error detection circuit
C201 R201
AB2
D201
R202
C202
C203
L201
AB3
TRNS
C205
R204
R203
R206
R207
C206
C207
R205
PC1
IC3
24 V DC output
+
Figure 2-3-5 24 V DC output (smoothing)/error detection circuit
In the 24 V DC output circuit, the voltage generated on the secondary side of the
transformer (TRNS) is rectified by diode (D201) and is then smoothed into 24 V DC by
the choke coil (L201) and the capacitor (C203).
Capacitors and resistors (C201, R201, C202, R202) that are arranged in parallel with
each diode of (D201) form a CR snubber circuit to absorb the surge voltage generated
during rectification, so noise is kept to a minimum.
Element (AB2, AB3) that are arranged in serial with each diode of (D201) form a
magnetic snubber to absorb the surge current generated during rectification, so noise is
kept to a minimum.
The error detection circuit detects fluctuations in the 24 V DC output using the shunt
regulator (IC3). These are isolated by the photocoupler (PC1) and fed back to the
switching control circuit in the form of control signal. The switching control circuit then
regulates the secondary side output by increasing the pulse width if the received output
voltage is too low and decreasing the pulse width if it is too high.