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PhD Thesis Defense: Ziyu Xia



9:00am - 11:00am ET

Jackson Conference Rm (C232) / Online

For info on how to attend via Zoom, please email

"Modeling and control of direct-conversion hybrid switched-capacitor DC-DC converters"


Efficient power delivery is increasingly important in modern computing, communications, consumer and other electronic systems, due to the high-power demand and thermal concerns accompanied by performance advancements and tight packaging. In pursuit of high efficiency, small physical volume, and flexible regulation, hybrid switched-capacitor topologies have emerged as promising candidates for such applications. By incorporating both capacitors and inductors as energy storage elements, hybrid topologies achieve high power density while still maintaining soft charging and efficient regulation characteristics. However, challenges exist in the hybrid approach. In terms of reliability, each flying capacitor should be maintained at a nominal 'balanced' voltage for robust operation (especially during transients and startup), complicating the control system design. In terms of implementation, switching devices in hybrid converters often need complex gate driving circuits which add cost, area, and power consumption.

This dissertation explores techniques that help to mitigate the aforementioned challenges. With various modeling, control, and design techniques, the application of hybrid switched-capacitor converters may be extended to scenarios that were previously challenging for them, allowing enhanced performance compared to using traditional topologies. For problems that may require future attention, this dissertation also points to possible directions for further improvements.

Thesis Committee

  • Prof. Jason T. Stauth (Chair)
  • Prof. Charles R. Sullivan
  • Prof. Minh Q. Phan
  • Prof. Robert C.N. Pilawa-Podgurski (External)


For more information, contact Theresa Fuller at