B. DC Power Supply
+24V (UA)
GND (UA)
Figure 3-68 Block diagram of DC power supply
The DC power supply, which is contained in the
DC power supply
&
main motor driver, generates and
outputs five DC voltages and two sequence control
signals.
When the main switch is turned ON, line voltage
is sent to low-voltage transformer PTL Low-voltage
transformer PT 1 changes the line voltage to lower AC
voltage, and sends the AC voltage to the DC power
supply.
The DC power supply full-wave rectifies the low
AC voltage with rectifiers 1, 2 and 3, and outputs
full-wave rectified pulses (ACP) from rectifier 2 as a.
sequence control signal.
The outputs from the three rectifiers are sent to
capacitors CSOl, C502, C503 and C504 for smooth-
ing, and output +24V(UA) by C504. The unregulated
DC voltage smoothed by CSOl, C502 and C503 is
sent to the series regulator. Since the +24V(UA) is
not regulated, it varies in response to line voltage.
The series regulator changes the unregulated DC
voltage to regulated DC voltage, and outputs its as
+SV, -SV, +24V(R) and +30V(UB). +30V(UB) is an
unregulated DC voltage
which
fluctuates with
AC voltage fluctuations.
The +SV series regulator outputs sequence
control signal (A), which causes +25V(R) and +30V
(UB) to switch ON and OFF after +SV does. Using
sequence control signal (A), the HVRST generator
outputs a TRUE HVRST signal, which actuates the
high-voltage power supply and microcomputer IC208
on the DC controller only when +SV is provided (and
HVRST is FALSE).
Power ON
'
Power OFF
'
+5V
(A)
HVRST
+24V
(R)
+30V (UB)
i--------·-------
1
I
I
Figure 3-69 Power-up sequence
In 220V /240V models, the over-voltage protec-
tion circuit detects the +30V (UB) voltage. If the
voltage exceeds the specified voltage, this circuit ac-
tuates the relay RLSOl, and cuts off +30V (UB) and
+24V(R).
COPYRIGHT
©
BY CANON INC. CANON LBP·CX SERIES REV.2 JULY 1985 PRINTED IN JAPAN (IMPRIME AU JAPONJ