TY - JOUR
T1 - A Resonant Switched-Capacitor Converter with GaN Transistors for High-Efficiency Power Delivery to Series-Stacked Processors
AU - Stillwell, Andrew
AU - Pilawa-Podgurski, Robert C.N.
N1 - Manuscript received November 29, 2018; revised March 4, 2019; accepted April 29, 2019. Date of publication May 20, 2019; date of current version August 4, 2020. This work was supported in part by the National Science Foundation, under Grant 1837924 and in part by the UIUC Strategic Research Initiative. Recommended for publication by Associate Editor Henry S. H. Chung. (Corresponding author: Robert C. N. Pilawa-Podgurski.) A. Stillwell is with the Department of Electrical and Computer Engineering, University of Illinois at Urbana\u2013Champaign, Urbana, IL 61801 USA (e-mail: [email protected]).
PY - 2020/9
Y1 - 2020/9
N2 - 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.
AB - 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.
KW - DC-DC power converters
KW - differential power processing (DPP)
KW - digital control
KW - resonant power converters
KW - switched capacitor (SC) circuits
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U2 - 10.1109/JESTPE.2019.2917658
DO - 10.1109/JESTPE.2019.2917658
M3 - Article
AN - SCOPUS:85090381447
SN - 2168-6777
VL - 8
SP - 3139
EP - 3150
JO - IEEE Journal of Emerging and Selected Topics in Power Electronics
JF - IEEE Journal of Emerging and Selected Topics in Power Electronics
IS - 3
M1 - 8718626
ER -