A High-Efficiency 4-Phase Series-Parallel Resonant Switched-Capacitor 48-to-3 V DC-DC Converter

A High-Efficiency 4-Phase Series-Parallel Resonant Switched-Capacitor 48-to-3 V DC-DC Converter

Lin, Ningchao (TU Delft Electrical Engineering, Mathematics and Computer Science)

Du, S. (mentor)

Delft University of Technology

Electrical Engineering | Electronic Instrumentation

2023-07-28

Resonant switch-capacitor (ReSC) is a type of hybrid switched-capacitor (HSC) which utilizes both inductor and capacitor, bearing the potential to overpower conventional switched-capacitor (SC) and magnetic-based converters. This work introduces a novel four-phase series-parallel resonant switch-capacitor (ReSC) DC-DC converter topology, which provides 16-to-1 conversion ratio and can serve as the unregulated first stage of two-stage 48V step-down voltage regulated module (VRM) for data centers. This topology can be treated as the cascade of one 4-to-1 SC stage and one 4-1 series parallel stage, the latter stage could reduce current stress on corresponding capacitors. The proposed converter uses 16 GaN switches, 5 flying capacitors and 1 inductor under the soft-switching condition. Phase changes under zero current switching (ZCS) conditions which greatly reduce their degradation to switches and extend their lifespan. Subsequently, when this topology serves as the first stage of two-stage VRM it could generate a 3V intermediate voltage, reducing voltage stress on the second regulation stage compared with a conventional 12V intermediate bus. A discrete prototype validates the analysis and achieves a fixed 16:1 conversion ratio, 96.5\% peak efficiency, and up to 460W/in$^3$ power density with a 48-V input voltage level.

DC-DC power conversion
two-stage VRM
multi-phase resonant switched capacitor
zero-current-switch

http://resolver.tudelft.nl/uuid:e6018037-c995-4de2-9f3b-b06be43d42b9

Student theses

master thesis

© 2023 Ningchao Lin