IMX35 Series: 35W DC-DC Converters
9-36V, 18-75V, 40-121V & 60-150V Inputs
Dual/Triple/Quad Outputs 3.3V, 5V, 12V & 15V
Safety of operator accessible output circuit
Product Specifications
Aug 2002
IEC/EN 60950 up to a configured output voltage (sum of
nominal voltages if in series or +/– configuration) of 42 V.
If the output circuit of a DC-DC converter is operator acces-
sible, it shall be an SELV circuit according to the IEC/EN
60950 related safety standards
However, it is the sole responsibility of the installer to en-
sure the compliance with the relevant and applicable safety
regulations. More information is given in: Technical Infor-
mation: Safety.
The following table shows some possible installation con-
figurations, compliance with which causes the output circuit
of the DC-DC converter to be an SELV circuit according to
Table 19: Insulation concept leading to an SELV output circuit
Conditions Front end
DC-DC converter
Result
Supply
voltage
Minimum required grade Maximum Minimum required
of isolation, to be provided DC output safety status of the
Type
Measures to achieve the Safety status of
specified safety status of the DC-DC
by the AC-DC front end,
including mains supplied
battery charger
voltage
from the
front end 1
front end output
circuit
the output circuit
converter output
circuit
Mains
≤250 V AC
Basic
<60 V
<75 V
Earthed SELV circuit 2 IMX 35 Operational insulation
(provided by the DC-DC
SELV circuit
converter)
Hazardous voltage
secondary circuit
IMX 35 Input fuse 3 output sup-
pressor diodes 4, and
Earthed SELV
circuit
2
earthed output circuit
1 The front end output voltage should match the specified input voltage range of the DC-DC converter.
2 The earth connection has to be provided by the installer according to the relevant safety standard, e.g. IEC/EN 60950.
3 The installer shall provide an approved fuse (type with the lowest rating suitable for the application) in a non-earthed input conductor
directly at the input of the DC-DC converter (see fig.: Schematic safety concept). For UL’s purpose, the fuse needs to be UL-listed.
See also: Input Fuse.
4 Each suppressor diode should be dimensioned in such a way, that in the case of an insulation fault the diode is able to limit the output
voltage to SELV (<60 V) until the input fuse blows (see fig.22: Schematic safety concept).
10004
Fuse
+
~
Mains
Suppressor
diode
AC-DC
front
DC-DC
con-
Battery
SELV
end
verter
–
~
Earth
connection
Earth
connection
Fig. 22
Schematic safety concept. Use fuse, suppressor diode and earth connection as per table: Safety concept leading to an
SELV output circuit.
Description of Options
Table 20: List of options
Option
Function of option
Extended temperature range
Inhibit
Characteristic
–8
i
TA = –40...110°C, with airflow and derating
-
-
Z
Open frame
AUG 13, 2002
Rev 1.0
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