17-May-04
EPR-16 – LinkSwitch 2.75 W Charger/Adapter
9.5 Thermal Measurements
Figure 23 shows two thermal image photographs with a visual photograph as a
reference. With the board in free air, the first thermal image shows the hottest
components were LinkSwitch and the output diode, reaching 47 °C with an external
ambient of 22 °C.
When in the case, the internal ambient was measured by inserting a thermocouple into
the case (just visible in the lower image). Running the unit for 12 hours at 85 VAC input
and peak power output, the maximum internal ambient was 37 °C. This is confirmed by
the lower thermal image, which recorded a similar case temperature.
This additional 13 °C rise gives a device and diode temperature of 60 °C at 22 °C
ambient and 75 °C at 50 °C ambient, both very acceptable results.
LinkSwitch
Output Diode
LinkSwitch
Output Diode
Thermocouple
inserted into
case above
LinkSwitch
Figure 23 - Thermal Image Measurements of Board and Sealed Adapter, 85 VAC Input,
5.3 V, 500 mA Output, 22 °C External Ambient
Power Integrations
Page 23 of 36
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