EPR-21 Datasheet, PDF (19/32 Pages) Power Integrations, Inc. – Engineering Prototype Report (EP-21) - 30 W DC-DC Converter with DPA424

19-Nov-02
EPR-21 – 5 V, 30 W DC-DC Converter
11 Thermal Performance
Thermal performance of the EP-21 was measured in still air at room temperature with no
heat sink and with a Wakefield 628-65AB heat sink attached to the aluminum substrate
using Berquist Bond Ply 105 thermal adhesive. The supply was also tested in still air in a
thermal chamber with the ambient temperature adjusted for 110 °C base plate
temperature, both with and without a heat sink. The results are tabulated below.
Input Voltage
Item
Ambient
DPA-Switch (U1)
Transformer (T1)
Output Choke (L2)
Output Rectifier (D2)
Base Plate
36 VDC
25 °C
68 °C
67 °C
67 °C
73 °C
66 °C
48 VDC
25 °C
64.5 °C
64 °C
67 °C
71 °C
63 °C
72 VDC
25 °C
64 °C
64 °C
68.5 °C
72 °C
62 °C
Figure 12 – EP-21 Thermal Performance with Attached Heat Sink,
Room Temperature, Maximum Load.
Input Voltage
Item
Ambient
DPA-Switch (U1)
Transformer (T1)
Output Choke (L2)
Output Rectifier (D2)
Base Plate
36 VDC
76 °C
115° C
116 °C
112.5 °C
113 °C
110 °C
48 VDC
77 °C
113° C
115 °C
113 °C
113 °C
110 °C
72 VDC
82.5 °C
113 °C
117 °C
118 °C
117 °C
110 °C
Figure 13 – EP-21 Thermal Performance with Attached Heat Sink, Ambient
Temperature Adjusted for 110 °C Base Plate Temperature.
Input Voltage
Item
Ambient
DPA-Switch (U1)
Transformer (T1)
Output Choke (L2)
Output Rectifier (D2)
Base Plate
36 VDC
30 °C
87 °C
86 °C
82 °C
95 °C
86 °C
48 VDC
30 °C
82 °C
82 °C
80 °C
91 °C
81 °C
72 VDC
29 °C
80 °C
81.5 °C
82 °C
90.5 °C
80 °C
Figure 14 – EP-21 Thermal Performance, No Heat Sink, Room Temperature,
Maximum Load.
Page 19 of 32
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