Conclusion

AN2252

20/21

Note that the ESBT switch does not have any external heat sink attached to its case. The

other most heating elements and sources of loss are the mains transformer and output

capacitors. Even when the loss generated by these passive components is minimized by a

suitable component selection and a good design, they are still significant overall converter

loss sources.

3

Conclusion

This application note shows how to build a high-input voltage power supply operating in

quasiresonant mode. The obtained efficiency is around the target value and can be further

improved by introducing a synchronous rectifier in the place of the secondary diode. With its

high speed, low conduction loss and low turn-on loss, the ESBT does not need a heatsink to

be used as a primary switch.

As this power supply is designed for use as an auxiliary supply, and only part of the

application is supplied from its input bulk capacitor, the EMI filter was not accommodated on

the board and the power supply was not tested for EMC compliance.

4

References

●

enhance the switching performances”

●

AN1889, “ESBT STC03DE170 IN 3-PHASE AUXILIARY POWER SUPPLY”

5

Revision history

Table 7.

Temperatures of the power switches at full load

Input voltage [VDC]

ESBT temperature [°C]

Diode D12 temperature [°C]

450

80.5

82

620

79.7

80.2

Table 8.

Revision history

Date

Revision

Changes

Dec-2005

1

First issue

28-Nov-2006

2

- The document has been reformatted

- Table 2. and Figure 5. modified