An Isolated Power Factor Corrected Power Supply Utilizing the Transformer Leakage Inductance

TL;DR

This paper presents a compact isolated power factor corrected power supply that uses transformer leakage inductance for boost functionality, enabling controlled startup and improved power factor correction.

Contribution

It introduces a novel approach utilizing transformer leakage inductance for power factor correction in isolated power supplies, eliminating the need for dedicated boost inductors.

Findings

Prototype confirms effective power factor correction

Controlled startup without surge components achieved

Waveform analysis validates design performance

Abstract

The widespread use of electronic devices increases the need for compact power factor corrected power supplies. This paper describes an isolated power factor corrected power supply that utilizes the leakage inductance of the isolation transformer to provide boost inductor functionality. The bulk capacitor is in the isolated part of the power supply allowing for controlled startup without dedicated surge limiting components. A control method based on switch timing and input/output voltage measurements is developed to jointly achieve voltage regulation and input power factor control. A prototype design is implemented with detailed measurements and waveforms shown to confirm the desired functionality.