40IMX7-05-8 Datasheet, PDF (8/14 Pages) Power-One – IMX7, IMS7 Series Data Sheet 7-Watt DC-DC Converters

IMX7, IMS7 Series Data Sheet
®
7-Watt DC-DC Converters
Thermal Considerations
If the converter, mounted on a PCB, is located in free, quasi-
stationary air (convection cooling) at the maximum ambient
temperature T_{A max} (see table Temperature specifications) and
is operated at nominal input voltage and output power, the
case temperature T_C measured at the measuring point of
case temperature (see Mechanical Data) will approach T_{C max}
after 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, such as input voltage, output
current, airflow, temperature 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 conditions, T_A may be higher or lower.
Caution: The case temperature T_C measured at the measuring
point of case temperature (see Mechanical Data) may under no
circumstances exceed the specified maximum. The installer must
ensure that under all operating conditions T_C remains within the
limits stated in the table Temperature specifications.
P_o/P_{o max}
JM017
Output Overvoltage Protection
The outputs are protected against overvoltage by Zener
diodes. In the event of an overvoltage, the converter will shut
down and attempt to restart automatically. The main purpose
of this feature is to protect against possible overvoltage,
which could occur due to a failure in the feedback control
circuit. The converters are not designed to withstand external
overvoltages applied to the outputs.
Connection in Series or Parallel
The outputs of single- or double-output models can be
connected in series without any precautions, taking into
consideration that the output voltage should remain below 60
V for SELV operation.
Both outputs of double-output models can be connected in
parallel without any precautions. Several converters (single-
or double-output models) with equal output voltage can be put
in parallel and will share their output current quite equally.
However, this may cause start-up problems and is only
recommended in applications, where one converter is able to
deliver the full load current, e.g., in true redundant systems.
1.0
0.8
0.5 m/s = 100 LFM
0.6
natural cooling
0.4
0.2
0
20 40 60
80 100 °C ^TA
Fig. 6
Maximum allowed output power versus ambient temperature
Short-Circuit Behavior
The current limitation shuts down the converter, when a short
circuit is applied to the output. It acts self-protecting, and
automatically recovers after removal of the overload condition.
V_o [%]
100
70
overload short-circuit condition
switch-off
05041b
0
Fig. 7
Overload switch-off (hiccup mode).
t
0.3 s
V_o [V]
5.5
05087a
5.0
4.5
4.0
3.5
3.0
0
0.4
0.8
1.2
1.6
I_o [A]
Fig. 8a
V_o versus I_o (typ.) of single-output models with V_o = 5.1 V
V_o [V]
13
05086b
12
11
10
9
8
7
0
0.2
0.4
0.6
0.8 I_{o total} [A]
Fig. 8b
V_o versus I_o (typ.) of double-output models (2 ×12 V) with both
outputs in parallel
BCD20007-G Rev AE, 14-May-2012
Page 8 of 14
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