A 2.2-MHz Active-Clamp Buck Converter for Automotive Applications

Chenhao Nan, Raja Ayyanar, Youhao Xi

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Automotive point-of-load dc-dc converters have a wide input voltage range from 4.5 to 42 V and, in order to avoid the AM band interference and comply with the strict CISPR-25 standard for electromagnetic interference (EMI) performance, the switching frequency is desired to be higher than 2 MHz. Buck converter is currently employed for such applications owing to its simplicity and low cost, but it has low efficiency at high switching frequencies and high EMI noise emission due to hard switching. A new active-clamp buck converter is proposed in this paper, which features zero-voltage-switching for main and auxiliary switches, and soft turnoff for synchronous rectifier over a wide input voltage range. The detailed operating principle analysis and several important design considerations are presented. Extensive design equations that can be adapted for other specifications and applications are also derived. A 2.2 MHz, 5V/5A prototype converter with only Silicon mosfets has been designed, built, and tested. The experimental results verify the converter operation and demonstrate the superior performance of the proposed active-clamp buck converter.

Original languageEnglish (US)
Article number7862295
Pages (from-to)460-472
Number of pages13
JournalIEEE Transactions on Power Electronics
Issue number1
StatePublished - Jan 2018


  • 2.2 MHz
  • Active-clamp
  • automotive DC-DC
  • buck converter
  • soft switching

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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