Oki PACEMARK 4410 - 2.1.15 Power supply circuit

40496501TH Rev.1 34
2.1.15 Power supply circuit
This switching type power supply circuit supplies the +5 VDC, ±12 VDC and +44 VDC.
Rectification and
smoothing circuit
+44 V primary
switching circuit
Noise filter
circuit
Alarm control
circuit
Switching
control circuit
AC input monitoring
circuit
Rectification and
regulating circuit
+5 V and ±12 V
primaty switching
circuit
Rectification and
smoothing circuit
POWONREST
circuit
+44V
POWALM-P
POWOFF-P
POWDWN-P
+5V
+12V
-12V
POWONRST-N
ACDOWN-P
SW
ACIN
FUSE
The uses of output voltages and signals are described below.
Voltage/ signal Use
+5V Logic IC/ LED drive voltage
+12V Logic IC drive voltage, option interface line voltage and LF motor locking
voltage
-12V Option interface line voltage
+44V Printhead, SP motor, LF motor, Other motors drive voltage
POW ALM-P Out put from the power supply circuit upon detection of an abnormal
temperature rise in the power supply circuit or an overcurrent of +44V.
The control unit suppresses the overcurrent by two-pass printing. If the
output does not change, the power supply circuit shuts off all DC output.
POW OFF-P Output from the main PCB upon detection of an abnormality in the print head,
SP motor, LF motor, Other motor driver circuit, and shut all DC output off.
AC DOWN-P Output from the power supply circuit to the main PCB upon detection of no
AC input with the AC switch turned off. Then the main PCB outputs the
POWOFF-P signal to the power supply circuit to have the necessary
information written into EEPROM.
POW DWN-P Output from the main PCB to the power supply circuit upon detection of no
host or operator access for approx. 10 min., to start the power-save mode.
In this mode, the power supply circuit cuts off 44V output.
POW ONRST-N Output form the power supply reset circuit to the main PCB. On receiving the
POWONRST-N signal, the main PCB prepares the main PCB RESET-N
signal and +5VD.
Figure 2.19