THERMAL CONSIDERATIONS | THERMAL CURVES |
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 |
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heated vertical wind tunnels that simulate the thermal | Figure 22: Temperature measurement location |
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environments | encountered | in | most | electronics |
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The allowed maximum hot spot temperature is defined at 120℃ | ||||||||||||||||||||
equipment. This type of equipment commonly uses | ||||||||||||||||||||
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vertically mounted circuit cards in cabinet racks in which |
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| Q48SP12017(Standard) | Output Current vs. Ambient Temperature and Air Velocity |
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the power modules are mounted. |
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| @Vin = 48V (Transverse Orientation) |
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| Output Current(A) |
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| 600LFM |
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The following figure shows the wind tunnel | 18 |
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| 500LFM |
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characterization setup. The power module is mounted | 16 |
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| 400LFM |
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on a test PWB and is vertically positioned within the | 14 |
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wind tunnel. The space between the neighboring PWB | 12 |
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and the top of the power module is constantly kept at | 10 |
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6.35mm (0.25’’). |
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| 8 | Natural |
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| Convection |
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Thermal Derating |
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| 100LFM |
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| 200LFM |
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| 4 |
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| 300LFM |
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Heat can be removed by increasing airflow over the |
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2 |
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module. The module’s maximum hot spot temperature | 0 |
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| Ambient Temperature (℃) | ||||||||
is pending to | release | and | the measured | location is | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | |||||
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| 75 | 80 | 85 | ||||||||||||
illustrated in Figure 22. | To enhance system reliability, | Figure 23: Output current vs. ambient temperature and air |
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the power module should always be operated below the | velocity@ Vin=48V (Transverse orientation) |
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maximum operating temperature. If the temperature |
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exceeds the maximum module temperature, reliability of |
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the unit may be affected. |
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FACING PWB
AIR VELOCITY
AND AMBIENT
TEMPERATURE
MEASURED BELOW
THE MODULE
PWB
MODULE
50.8 (2.0”)
AIR FLOW
12.7 (0.5”)
Note: Wind Tunnel Test Setup Figure Dimensions are in millimeters and (Inches)
Figure 21: Wind tunnel test setup
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DS_Q48SP12017_05302008