2GL/2FV/2FW
2-3-1
2-3 Operation of the PWBs
2-3-1 Power source PWB
Figure 2-3-1 Power source PWB block diagram
The power source PWB consists of the switching regulator section that is the main part, other zero cross signal detection
circuit and heater lamp control circuit. The switching regulator circuit consists of the noise filter circuit, rectification smooth-
ing circuit, switching control circuit, 5 V DC rectification/smoothing output circuit, 24 V DC rectification/smoothing output
circuit and overvoltage detection circuit, and this circuit converts the AC power input to the 5 V DC and 24 V DC power
source by the switching operation and outputs it to the engine/high voltage PWB. The zero cross signal detection circuit
detects the 0 V point (zero cross) of the AC wave form and outputs to the engine/high voltage circuit, and the engine/ high
voltage PWB outputs the heater lamp ON signal (HEATN) to the heater lamp control circuit based on the timing of zero
cross signal (ZCROSS) and controls the AC power loading to the heater lamp.
D
10 to 13
D
31
D
32
C8
F
1
F
2
SW1
NTC1
Q1
T1
Switchin
g
control
circuit
24 V
D
C
rectification/
smoothin
g
output circuit
TRA1
Heater
lamp
Thermal
cutout
Heater
lamp
control
circuit
Power source PWB
PC1
PC5
PC2
Noise
filter
circuit
(L1)
Rectification
smoothin
g
circuit
24V1
5V
G
N
D
G
N
D
HEATN
24V2
Power
switch
AC
input
Exit sensor
Z
CROSS
SLEEP
5 V
D
C
rectification/
smoothin
g
output circuit
EXITN
PC3
Pulse
O
v
er
v
olta
g
e
d
etection
circuit
(IC101)
PC4
Z
ero cross
si
g
nal
d
etection
circuit
Summary of Contents for LP 3118
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