Datasheet

Thermal measurements AN2838
14/23 DocID15099 Rev 2
4 Thermal measurements
To check the reliability of the design, thermal mapping by means of an IR camera was
carried out. Figure 20 and Figure 21 show thermal measurements on the component side of
the board at nominal input voltages and full load. Some pointers visible on the pictures
placed across key components show the relevant temperature. Table 1 provides the
correlation between the measured points and components, for both thermal maps. The
ambient temperature during both measurements was 27 °C. According to these
measurement results, all components on the board function within their temperature limits.
Figure 20. Thermal map at 90 V
AC
- full
load
Figure 21. Thermal map at 265 V
AC
- full
load
Table 2. Measured temperature @ 90 V
AC
and 265 V
AC
- full load
Component Temperature @ 90 V
AC
Temperature @ 265 V
AC
MOSFET Q1 57.8 °C 43.8 °C
Secondary diode D5 58.9 °C 58.1 °C
Diode bridge D1 65.9 °C 45.6 °C
Transformer TR1 (bobbin) 64.3 °C 65.1 °C
Transformer TR1 (core) 54.5 °C 55 °C
Choke T1 55.7 °C 36. 2 °C
Choke T2 56 °C 38.2 °C
Transil D2 70 °C 59 °C