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AN1376 APPLICATION NOTE

The highest temperatures are for the NTC thermistor, the filter inductor, the input bridge, the

clamp diode (D9), the 5V regulator and the output diodes D7 and D6. The temperature rise of

the transformer is around 40 °C.

Regarding the thermistor, the bridge and the output diodes the temperature rise is compatible

with reliable operation of the circuit.

Figure 29.

At 220Vac the input circuitry is thermally less stressed and generally the component temper-

ature rise is lower.

@220VAC - FULL LOAD

COMPONENT SIDE

A 39.31°C

B 54.21°C

C 80.15°C

D 60.05°C

E 72.00°C

SMD SIDE