2-11
3. Function and overview of each board
3.4 LINE FIL (05P0707)
The LINE FIL Board located between the power connector and the SW REG board is a EMC line filter.
Protection against power short-circuiting is performed by a polymer switch.
LINE FIL block diagram LINE FIL block diagram
LINE FIL block diagram LINE FIL block diagram
LINE FIL block diagram
FF
FF
F
or ror r
or ror r
or r
efef
efef
ef
erer
erer
er
ence:ence:
ence:ence:
ence:
P P
P P
P
olol
olol
ol
ymer symer s
ymer symer s
ymer s
witcwitc
witcwitc
witc
hh
hh
h
The polymer switch is a polymer base PTC (Positive Tem-
perature Coefficient) thermistor , which is a device whose
resistance rapidly changes when element temperature rises
above a certain value. Change of resistance is as large as 10
4
to 10
6
. The polymer switch is an overcurrent and overheating
protection component that restricts current amperage mini-
mum utilizing this characteristic, in which temperature and
resistance rise when the electric circuit allows overcurrent to
flow or is heated by rise of ambient temperature. The change
of resistance is reversible, and component temperature falls
when power is once turned off and resistance returns to
original value, so that it need not be replaced unlike a fuse.
FL1
1 24V+
2 24V-
1 24V+
2 24V-
C1
C2
C4 C3
J1
J1
J2
F1
F2
4A
4A
SW REG
05P0705
0
50 100 150 200
0.1
1
10
100
1000
10000
TEMPERATURE (degree)
RESISTANCE ohms
3.5 SW REG (05P0705)
The SW REG Board is a switching regulator of I/O isolating type, whose input voltage is 24V DC
+30%, -10% and output voltage is +15V, 3A. The oscillation frequency of the switching regulator
depends on capacity of C26 connected to U2, and is set at 200kHz approximately. Over-input voltage is
set by Zener voltage of VR3 and VR4. When power more than the Zener voltage of 35V is input, Q4 is
turned ON, controlling “18V AVR” of Q2, Q3, and the switching regulator stops oscillating.
Further, overcurrent is detected by source resistor R21 to R23 of Q1. Amperage through the 24V input
line is restricted to under 3.1A.
Reverse connection of the power supply is protected by diode CR1, inserted to power input line in series.
Q1
CR1
CR2
R19
TP1
TP2
IS+
OUT
CT
FB
Cs
REC
Vcc
GND
T1
FL1
FL2
U2
U4
U3
AVR
5,6 +15V
7,8 GND
1 24V+
2 24V-
1 24V+
2 24V-
3 Power ON
Power ON
Q2,3,VR1
18V AVR
R21-23
FA5304P
2SK1432
C26
220pF
TLP521
-1GB
PC1093J
C16C17
J1
J2
F1
1.35A
FML-22S
FML-22S
IN-
VR2
Power SW
35V Overvolt DET
VR3VR4
Q4
Q5
Q6
SW REG block diagramSW REG block diagram
SW REG block diagramSW REG block diagram
SW REG block diagram
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