2026-09-19T19:42:19Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/88081 2023-07-11 col_2142_5131 col_2142_8888 com_2142_5130 com_2142_8887 com_2142_234

Pilawa, Robert Stillwell, Andrew R 2015-09-29T20:38:39Z 2015-09-29T20:38:39Z 2015-08 2015-07-21 The series-stacked architecture provides a method to increase power delivery efficiency to multiple processors. 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 work demonstrates a switched-capacitor (SC) converter to balance a stack of four ARM Cortex-A8 based embedded computers. A model of a series-stack with no DPP is first discussed for the case when loads can be controlled with no power electronics. We investigate hard-switched and resonant modes of operation in a ladder SC DPP converter, implemented with GaN transistors. Excellent 5 V regulation of each embedded computer is demonstrated in a 4-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 99.8% is demonstrated, and DPP switching frequencies from 250 kHz to 2 MHz. Finally, the reliability of a series-stacked system is compared to an electrically parallel system. Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2015-09-29 without embargo terms The student, Andrew Stillwell, accepted the attached license on 2015-07-17 at 16:25. The student, Andrew Stillwell, submitted this Thesis for approval on 2015-07-17 at 16:32. This Thesis was approved for publication on 2015-07-21 at 13:39. DSpace SAF Submission Ingestion Package generated from Vireo submission #8546 on 2015-09-29 at 13:23:10 Made available in DSpace on 2015-09-29T20:38:39Z (GMT). No. of bitstreams: 2 STILLWELL-THESIS-2015.pdf: 2931945 bytes, checksum: 270e6fb62ba81f1024deed384e37ff1f (MD5) LICENSE.txt: 4213 bytes, checksum: 0b67bec5a2e0c093368ac0dda8273b13 (MD5) Previous issue date: 2015-07-21 application/pdf http://hdl.handle.net/2142/88081 en Copyright 2015 Andrew Stillwell power switched-capacitor Differential power processing for series-stacked processors text text 2015-8 Electrical & Computer Engineering Electrical & Computer Engineering University of Illinois at Urbana-Champaign Thesis M.S.