Thermal Considerations; Thermal Curves - Delta Electronics Delphi Q48SP Datasheet

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
equipment. This type of equipment commonly uses
vertically mounted circuit cards in cabinet racks in which
the power modules are mounted.
The following
characterization setup. The power module is mounted
on a test PWB and is vertically positioned within the
wind tunnel. The space between the neighboring PWB
and the top of the power module is constantly kept at
6.35mm (0.25'').
Thermal Derating
Heat can be removed by increasing airflow over the
module. The module's maximum hot spot temperature
is pending to release and the measured location is
illustrated in Figure 22. 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.
FACING PWB
AIR VELOCITY
AND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
Figure 21: Wind tunnel test setup
DS_Q48SP12017_05302008
in most
figure shows the wind
PWB
MODULE
50.8 (2.0")
AIR FLOW
12.7 (0.5")

THERMAL CURVES

Figure 22: Temperature measurement location
electronics
The allowed maximum hot spot temperature is defined at 120
Output Current(A)
20
18
tunnel
16
14
12
10
Natural
8
Convection
6
4
2
0
20 25
Figure 23: Output current vs. ambient temperature and air
velocity@ V
Q48SP12017(Standard) Output Current vs. Ambient Temperature and Air Velocity
@Vin = 48V (Transverse Orientation)
100LFM
200LFM
300LFM
30 35 40 45 50 55 60
=48V (Transverse orientation)
in
℃
600LFM
500LFM
400LFM
65 70 75 80 85
Ambient Temperature (℃)
10