April 2011 Doc ID 13127 Rev 5 1/36
AN2495
Application note
3-phase 80 W SMPS with very wide-range input voltage
based on the L6565 and ESBT
®
STC04IE170HV
1 Introduction
The purpose of this application note is to explain the design of an 80 W 3-phase auxiliary
power supply for motor drives and welding applications. To reach a high level system in
terms of both efficiency and cost, the L6565 PWM controller has been selected as well as
the STC04IE170HV as the main switch. The combination of these STMicroelectronics™
parts provides a highly efficient solution for high DC input voltage, a typical requirement of
any three-phase application. The L6565 driver is a variable frequency PWM driver suitable
for a design flyback converter working in quasi-resonant mode. It also includes some very
useful additional features.
The frequency response study reported in the this document is carried out using MATLAB.
All the design choices are thoroughly discussed to allow the user to adapt the project to
specific needs. The input voltage can also be extended up to 1000 VDC as enough margin
exists to do so. Finally, the experimental results are analyzed to better understand the
benefits offered by the use of ESBT
®
in this application.
The document is associated with demonstration boards STEVAL-ISA019V1, STEVAL-
ISA019V2 and STEVAL-ISA019V3 (Figure 1).
Figure 1. 80 W 3-phase SMPS (working prototype)
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