Power Supply System; Power Supply; Outline Of The Power Supply; Protection Function - Canon ImageRunner iR8500 Series Service Manual

11.4 Power Supply System

11.4.1 Power Supply

11.4.1.1 Outline of the Power Supply

iR105i/iR105+ / iR9070 / iR85+ / iR8070
The machine's DC power is supplied by the DC power supply PCB and the relay PCB.
PCB
DC power supply
PCB
Relay PCB

11.4.2 Protection Function

11.4.2.1 Protective Functions

iR105i/iR105+ / iR9070 / iR85+ / iR8070
The machine is designed to automatically stop the output of the DC power supply as soon as the overcurrent protective mechanism turns on.
If an overcurrent is detected by the overcurrent detection circuit A, outputs [1] and [2] are stopped; this is to prevent malfunction of the machine, as output
[1] is used by the logic system.
If the overcurrent detection circuit B detects an overcurrent, output [2] is stopped.
Detection by
Overcurrent detection
circuit A
Function
- Generates DC power from AC power.
- Protects against overcurrent.
- Generates DC power from DC power (24V->18V)
- Distributes DC power to loads.
- Protects each load against overcurrent.
DC power supply PCB
Converter
Overcurrent
circuit 1
protection
circuit 1
3.3V/5V/+8V
-8V/12V/15V
Overcurrent
Converter
protection
circuit 2
circuit 2
24V/38V
Sequence
control
circuit
Machine operation
Stops outputs [1] and [2]
from the DC power
supply PCB.
T-11-17
Relay PCB
Output [1]
5V
Overcurrent
detection
circuit A
12V
3.3V
+8V
-8V
15V
Output [2]
Overcurrent
detection
38V circuit B
24V
Overcurrent
J1701
detection signal 2
5
Overcurrent detection signal 1
4
Outputs [1] and [2] are stopped.
Output [2] is stopped.
F-11-12
T-11-18
Resetting
Turn off the main power switch, and remove the
cause; then, leave the machine alone for about 3
min, and turn on the main power switch.
Chapter 11
0007-0790
0007-0808
11-15