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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 height of this fan duct is constantly kept
at 25.4mm (1'').
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.
PWB
FACING PWB
MODULE
AIR VELOCITY
AND AMBIENT
TEMPERATURE
MEASURED BELOW
50.8 (2.0")
THE MODULE
AIR FLOW
12.7 (0.5")
25.4 (1.0")
Figure 31: Wind tunnel test setup figure dimensions are in
millimeters and (inches)
DS_IPM24S0B0_03202007
10
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