Thermal Considerations; Thermal Curves - Delta Electronics Delphi Q48DR 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 figure
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 hottest spot is less than + 120°C.
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 26: Wind tunnel test setup
DS_Q48DR1R533_03152007
in most electronics
shows the wind tunnel
PWB
MODULE
50.8 (2.0")
AIR FLOW
12.7 (0.5")

THERMAL CURVES

Figure 27: Hot spot temperature measured point
＊
The allowed maximum hot spot temperature is defined at 120
Q48DR1R533(standard) Output Load vs. Ambient Temperature and Air Velocity
Output Load(%)
@Vin = 48V (Transverse Orientation)
110%
100%
90%
80%
Natural
Convection
70%
60% 100LFM
200LFM
50%
300LFM
40%
30%
20%
10%
0%
20 25 30 35 40 45
Figure 28: Output load vs. ambient temperature and air velocity
@V =48V(Transverse Orientation)
in
400LFM
500LFM
50 55 60 65 70 75 80
Ambient Temperature (℃)
13
℃
85