
A
A
A E
E
E E
E
E 0
0
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1
1 L
L
L 2
2
2 4
4
4 ////L
L
L 4
4
4 8
8
8 D
D
D C
C
C --D
D
D C
C
C C
C
C o
o
o n
n
n v
v
v e
e
e rrrrtttte
e
e rrrrs
s
1
1 8
8
8 --3
3
3 6
6
6 V
V
V d
d
d c
c
c a
a
a n
n
n d
d
d 3
3
3 6
6
6 --7
7
7 2
2
2 V
V
V d
d
d c
c
c IIIIn
n
n p
p
p u
u
u tttt,,,, 1
1
1 0
0
0 W
W
Wa
a
a tttttttt S
S
S iiiin
n
n g
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-17-
47
F/100V electrolytic capacitor is recom-
mended for C1.
For conditions where EMI is a concern, a differ-
ent input filter can be used. Figure 4 shows an
input filter designed to reduce EMI effects. L1 is
a 12
H differential inductor, C1is a 47F/100V
electrolytic capacitor, and C2 is a 1
F/100V
metal film or ceramic high frequency capacitor.
When a filter inductor L1 is connected in series
with the power converter input, an input capac-
itor C2 should be added. An input capacitor C2
should also be used when the input wiring is
long, since the wiring can act as an inductor.
Failure to use an input capacitor under these
conditions can produce large input voltage
spikes and an unstable output.
Input-Output
Characteristic
Isolation
The isolation voltage between input to output,
input to case and case to output are all greater
than 500 Volt DC. If the system using the power
module needs to meet safety agency approval,
certain rules must be followed in the design of
the system using the module. In particular, all of
the creepage and clearance requirements of
the end-use safety requirement must be
observed. These documents include EN60950,
UL-1950, and CSA 22.2-960. Also specific
applications need to receive other or additional
requirements.
Safety Consideration
For safety-agency approval of the system in
which the power module is used, the power
module must be installed in compliance with the
spacing and separation requirements of the
end-use safety agency standard, i.e., UL1950,
CSA C22.2 No. 950-95, and EN60950. The
input-to-output 500VDC isolation is an opera-
tional insulation. The DC/DC power module
should be installed in end-use equipment, in
compliance with the requirements of the ulti-
mate application, and is intended to be supplied
by an isolated secondary circuit. When the sup-
ply to the DC/DC power module meets all the
requirements for SELV(<60Vdc), the output is
considered to remain within SELV limits (level
3). If connected to a 60Vdc power system, dou-
ble or reinforced insulation must be provided in
the power supply that isolates the input from
any hazardous voltages, including the ac
mains. One Vi pin and one Vo pin are to be
grounded or both the input and output pins are
to be kept floating. Single fault testing in the
power supply must be performed in combina-
tion with the DC/DC power module to demon-
strate that the output meets the requirement for
SELV. The input pins of the module are not
operator accessible.
Note: Do not ground either of the input pins of
the module, without grounding one of the output
pins. This may allow a non-SELV voltage to
appear between the output pin and ground.
+Vin
-Vin
C1
Fig.3 Ripple Rejection Input Filter
+Vin
-Vin
C1
C2
L1
Fig.4 EMI Reduction Input Filter
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