AN3014

Thermal map

Doc ID 16064 Rev 2

17/29

5

Thermal map

In order to check design reliability, thermal mapping by means of an IR camera was done.

Below, thermal measurements of the component side of the board at nominal input voltage

are shown. The pointers on the images have been placed across key components. The

ambient temperature during both measurements was 27 °C.

Figure 16.

Thermal map at 115 Vac - 60 Hz - full load

Figure 17.

Thermal map at 230 Vac - 50 Hz - full load

The pictures highlight that although both the synchronous rectifier MOSFETs at secondary

side are working without a heatsink, their operating case temperature is lower than 60 °C.

Table 4.

Thermal map reference points

Point

Reference

Description

A

L1

EMI filtering inductor

B

D1

Bridge rectifier

C

L2

PFC inductor

D

D4

PFC output diode

E

Q3

Resonant high-side MOSFET

F

T1

Resonant power transformer

G

Q11

Output rectifier MOSFETs (hottest spot)