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A Resonant Switched-Capacitor Converter With GaN Transistors for High-Efficiency Power Delivery to Series-Stacked Processors

2019; Institute of Electrical and Electronics Engineers; Volume: 8; Issue: 3 Linguagem: Inglês

10.1109/jestpe.2019.2917658

2168-6785

Andrew Stillwell, Robert C. N. Pilawa-Podgurski,

Energy Harvesting in Wireless Networks

The series-stacked architecture provides a method to increase power delivery efficiency to multiple processors by leveraging the inherent voltage step-down properties of series-connected elements. With a series stack, differential power processing (DPP) is needed to ensure that processor voltages remain within design limits, as the individual loads vary. This paper demonstrates a switched-capacitor (SC) converter to balance a stack of four ARM Cortex-A8-based embedded computers. We investigate hard-switched and resonant modes of operation in a ladder SC DPP converter implemented with GaN transistors. Operation within supply limits of each embedded computer is demonstrated in a four-series-stack configuration with realistic computational workloads. Moreover, we demonstrate hot-swapping of individual computers with maintained voltage regulation at all nodes. A peak stack power delivery of 99% is experimentally measured, and DPP switching frequencies from 200 kHz to 2 MHz are demonstrated.