
6
THERMAL CONSIDERATIONS
Thermal management is an important part of the
system design. To ensure proper, reliable operation,
sufficient cooling of the power module is needed over
the entire temperature range of the module.
Convection cooling is usually the dominant mode of
heat transfer.
Hence, the choice of equipment to characterize the
thermal performance of the power module is a wind
tunnel.
Thermal Testing Setup
Delta’s DC/DC power modules are characterized in
heated vertical wind tunnels that simulate the thermal
environments
encountered
in
most
electronics
equipment. This type of equipment commonly uses
vertically mounted circuit cards in cabinet racks in
which the power modules are mounted.
The
following
figure
shows
the
wind
tunnel
characterization setup. The power module is mounted
on a test PWB and is vertically positioned within the
wind tunnel. The space between the facing PWB and
PWB is constantly kept at 25.4mm (1’’).
Figure 7: Wind tunnel test setup
Thermal Derating
Heat can be removed by increasing airflow over the
module. To enhance system reliability, the power
module should always be operated below the maximum
operating temperature. If the temperature exceeds the
maximum module temperature, reliability of the unit
may be affected.
THERMAL CURVES
DDW1000series Output Current vs. Ambient Temperature and Air Velocity
(Either Orientation)
0%
20%
40%
60%
80%
100%
120%
25
35
45
55
65
75
85
Ambient Temperature (℃)
Output Power (%)
Natural
Convection
Figure 8: Derating Curves