HWD075DGE Datasheet, PDF (9/15 Pages) Power-One – HWD Series . 75 Watt, Half-Brick DC/DC Converter Wide Input Range Dual Output

HWD Series – 75 Watt, Half-Brick DC/DC Converter
Wide Input Range
Dual Output
Datasheet
Thermal Considerations
The power converter operates in a variety of thermal environments: however, sufficient cooling should be
provided to help ensure reliable operation of the converter. Heat-dissipating components are thermally coupled
to the case. Heat is removed by conduction, convection, and radiation to the surrounding environment. Proper
cooling can be verified by measuring the case temperature.
Heat Transfer Characteristics
Increasing airflow over the converter enhances the heat transfer via convection. Figure 3 shows the maximum
power that can be dissipated by the converter without exceeding the maximum case temperature versus local
ambient temperature (T_A) for natural convection through 400 ft/min.
Systems in which these converters are used generate airflow rates of 50 ft/min due to other heat dissipating
components in the system. Therefore, the natural convection condition represents airflow rates of approximately
50 ft/min. Use of Figure 3 is shown in the following example.
Example
What is the minimum airflow required for the device operating at 24 V, an output power of 60 W, and maximum
ambient temperature of 60 ºC.
Solution:
Given: Vi = 24 V, Po = 60 W, T_A = 60 ºC.
Determine P_D (Figure 4): P_D = 13 W.
Determine airflow (Figure 3): v = 200 ft/min
HWD15DGE - Power Derating
Natural
100 LFM
200 LFM
300 LFM
400 LFM
22
20
18
16
14
12
10
8
6
4
2
0
0
10
20
30
40
50
60
70
80
90
100
Ambient Temperature (C)
Figure 3. Power Derating Curve
REV. 9/01
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