Power Supply Section; Block Diagram Of Power Supply Section; Power Supply Section Structure - Canon BJC-8500 Service Manual

BJC-8500

4.3 Power Supply Section

The power supply section is a switching regulator that converts the input AC to the
various DC voltages to be used on the printer, and supplies these DC voltages to the
logic board.

4.3.1 Block diagram of power supply section

Protective Circuits
AC
Protective
Circuit
Inlet
Connected to
Power Cord

4.3.2 Power supply section structure

1) AC inlet
The AC inlet incorporates a GND terminal. The input voltages are as follows:
102V (120V
2) Internal circuits
Protective circuits
The protective circuits protect the internal circuits from overvoltage input and
eliminate electrical noise.
The protective circuits are provided with a fuse. This fuse blows to protect the
internal circuits in the event of an overvoltage input.
The fuse is installed in a fuse holder, and can be replaced if it blows due to
overvoltage.
Primary side circuits
The primary side circuits rectify and smooth the input AC voltage. This voltage is
then converted by the DC/DC converter, and supplied through the switching
circuit to the primary side of the transformer.
Secondary side circuits
The respective voltages are generated from the voltage at the transformer's
secondary voltage. VH and VM are generated by the switching circuit, and VCC is
generated by the constant voltage circuit.
Primary Side Circuits
Rectifier
Noise
and
Filter Smoothing
Circuit
Switching
Figure 4-39 Block Diagram of Power Supply Section
) to 264V (240V
-15% +10%
Secondary Side Circuits
Rectifier
and
Smoothing
Circuit
Circuit
Trans-
former
Rectifier
and
Smoothing
Circuit
)
4-41
Part 4: Technical Reference
VH
Switch
Circuit
VM
Output
Connector
Constant
VCC
Voltage
Circuit
Logic Board