Industrial Environment
Thermal Considerations
DC/DC Converters < 40W
Output overvoltage protection
IMS6 Series
If a converter, mounted on a PCB, is located in free, quasi-
stationary air (convection cooling) at the indicated maxi-
mum ambient temperature
T
A max
(see table:
Temperature
specifications)
and is operated at its nominal input voltage
and output power, the case temperature
T
C
measured at
the:
Measuring point of case temperature T
C
(see:
Me-
chanical Data)
will approach the indicated value
T
C max
af-
ter the warm-up phase. However, the relationship between
T
A
and
T
C
depends heavily on the conditions of operation
and integration into a system. The thermal conditions are
influenced by input voltage, output current, airflow, tem-
perature of surrounding components and surfaces and the
properties of the printed circuit board.
T
A max
is therefore
only an indicative value and under practical operating con-
ditions, the ambient temperature
T
A
may be higher or lower
than this value.
Caution:
The case temperature
T
C
measured at the
Measuring point of case temperature T
C
(see:
Mechani-
cal Data)
may under no circumstances exceed the speci-
fied maximum value. The installer must ensure that un-
der all operating conditions
T
C
remains within the limits
stated in the table
Temperature specifications.
Short Circuit Behaviour
The current limit characteristic shuts down the converter
whenever a short circuit is applied to its output. It acts self-
protecting and automatically recovers after removal of the
overload condition.
Typical Performance Curves
U
o
[V]
5.25
5.0
4.75
4.5
4.25
4.0
0
0.5
1.0
05056
The outputs of the IMS 6 converters are protected against
overvoltages by Zener diodes. In the event of an overvolt-
age on the output, the unit will shut-down and attempt to
restart automatically. The main purpose of this feature is to
protect against possible overvoltages which could occur
due to a failure in the feedback control circuit. The units are
not designed to withstand external overvoltages applied to
the outputs.
Connection in series
The outputs of single or dual output units can be connected
in series without any precautions, taking into consideration
that the highest output voltage should remain below 60 V for
SELV operation.
Connection in parallel
The outputs of several units with equal nominal output volt-
age can be connected in parallel. Approximate current
sharing between 2 or several units is ensured by their load
dependent output characteristic.
U
o1
+
U
o2
[V]
31.5
31
30.5
30
29.5
29
28.5
05057
I
o
[A]
0
33
66
100
133
166
200
233
I
o
[mA]
Fig. 12
U
o
versus I
o
(typ) of single output units (example for
48IMS6-05-9
U
o1
[V]
16.5
16
15.5
I
o2
= 140 mA
15
14.5
14
0
33
66
100
33
66
200
233
I
o1
[mA]
I
o2
= 14 mA
05058
Fig. 13
U
o
versus I
o
(typ) of dual output units ( 15 V), with 30 V
load connected to Vo+ and Vo–.
U
o1
,
U
o2
[V]
12.8
12.4
12
11.6
11.2
I
o1
[%]
I
o1 no
U
o2
U
o1
05059
0
150
300
Fig. 14
Cross load regulation of dual output units. U
o1
versus
I
o1
(typ) for various I
o2
(48IMS6-1515-9).
Fig. 15
Flexible load distribution on dual outputs (2
x
12 V) with
load variation from 0...150% of P
o1 nom
on output 1.
Output 2 loaded with 25% of P
o2 nom
.
Edition 1 06.00
POWER-ONE [ POWER-ONE ]
