Asymmetric slope compensation for digital hybrid current mode control of a three-level flying capacitor buck converter

Abdulkerim Uǧur, Murat YILMAZ*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The three-level flying capacitor (3LFC) buck converter has the potential to provide better efficiency and higher power density as compared to the traditional buck converter. However, due to the flying capacitor's instability issues, control is challenging. In this paper, the digital hybrid current mode (DHCM) control method, which combines the average and peak current mode control techniques, is modified and implemented to a 3LFC buck converter. For flying capacitor (FC) voltage balancing, a novel asymmetric slope compensation (ASC) technique is presented. The proposed ASC technique achieves FC voltage balancing by adjusting the slope compensation of the two switching pairs asymmetrically, and therefore is applicable to any type of digital peak current mode control (PCM) method. The ASC technique for DHCM control of the 3LFC buck converter is verified in simulations and experimentally with an ARMbased mixed-signal microcontroller on a 250-kHz, 24-V input, and 35-W/4-A output prototype. The overall control method enables the implementation of the 3LFC buck converter for accurate and fast current regulation, and therefore is especially advantageous for LED and laser diode driver applications.

Original languageEnglish
Pages (from-to)2345-2359
Number of pages15
JournalTurkish Journal of Electrical Engineering and Computer Sciences
Volume28
Issue number4
DOIs
Publication statusPublished - Jul 2020

Bibliographical note

Publisher Copyright:
© 2020 Turkiye Klinikleri. All rights reserved.

Keywords

  • Current mode control
  • DC-DC converters
  • Three-level flying capacitor buck converter

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