A high-switching-frequency flyback converter in resonant mode

Jianting Li, Frank B.M. van Horck, Bobby J. Daniel, Henk Jan Bergveld

Research output: Contribution to journalArticleAcademicpeer-review

30 Citations (Scopus)


The demand of miniaturization of power systems has accelerated the research on high-switching-frequency power converters. A flyback converter in resonant mode that features low switching losses, less transformer losses, and low switching noise at high switching frequency is investigated in this paper as an alternative to a conventional quasi-resonant (QR) flyback topology to increase power density. In order to find a compromise between magnet size, electromagnetic interference (EMI), and efficiency, the concept utilizes the resonant behavior between transformer leakage inductance and snubber capacitor to achieve near-zero-voltage switching at both turn-on and turn-off of the primary switch, low core loss due to a continuous transformer magnetizing current, and reduced EMI due to low di/dt and dv/dt values. Meanwhile, the concept uses the regenerative snubber to recycle the transformer leakage energy with two snubber diodes and one snubber capacitor. The proposed concept has been validated on a 340-kHz 65-W prototype. Compared to the conventional QR flyback converter operating at the same switching frequency, the proposed concept has 2% efficiency improvement and better EMI performance.

Original languageEnglish
Article number7792114
Pages (from-to)8582-8592
Number of pages11
JournalIEEE Transactions on Power Electronics
Issue number11
Publication statusPublished - 1 Nov 2017


  • Flyback
  • high switching frequency
  • regenerative snubber
  • resonant power conversion
  • switching loss


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