{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/98442"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/98442","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Voltage regulation of a series stacked system of digital loads by differential power processing","abstract":"A modern high-end multi-core microprocessor has very stringent power supply requirements. It can draw hundreds of amperes of current at supply voltages as low as 0.8 V. As the supply voltages keep decreasing, the power delivery to meet the supply requirements is becoming increasingly difficult and inefficient. However, the presence of multiple cores in the microprocessor offers us a way to power it at a higher voltage by series-stacking the cores. Differential power processing has been shown to be an efficient way to series-stack server loads. In this work we study the dynamics of the element-to-element DPP topology implemented with bi-directional buck-boost converters. Some of its dynamic drawbacks are pointed out and a topological modification to counter those drawbacks is proposed. We then develop a linear control to regulate processor core voltages in a series stack of 4 cores. A hysteretic control to accommodate light load modes in the bi-directional regulating converters is also discussed. Both the linear and the hysteretic controller are implemented successfully in hardware and efficiency improvement due to light-load modes is demonstrated.","abstract_html":"A modern high-end multi-core microprocessor has very stringent power supply requirements. It can draw hundreds of amperes of current at supply voltages as low as 0.8 V. As the supply voltages keep decreasing, the power delivery to meet the supply requirements is becoming increasingly difficult and inefficient. However, the presence of multiple cores in the microprocessor offers us a way to power it at a higher voltage by series-stacking the cores. Differential power processing has been shown to be an efficient way to series-stack server loads. In this work we study the dynamics of the element-to-element DPP topology implemented with bi-directional buck-boost converters. Some of its dynamic drawbacks are pointed out and a topological modification to counter those drawbacks is proposed. We then develop a linear control to regulate processor core voltages in a series stack of 4 cores. A hysteretic control to accommodate light load modes in the bi-directional regulating converters is also discussed. Both the linear and the hysteretic controller are implemented successfully in hardware and efficiency improvement due to light-load modes is demonstrated.","abstract_has_math":false,"creators":["Das, Dipanjan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"M.S.","degree_level":"Thesis","degree_discipline":"Electrical & Computer Engr","degree_department":null,"school":null,"contributors":["Krein, Philip T."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2017,"date_issued":"2017-09-29T17:57:13Z","date_published":"2017-09-29T17:57:13Z","updated_at":"2026-07-22T22:24:35Z","subjects":["Differential Power Processing","Series-stacked power delivery","Series stacking","Bidirectional power converters","Light-load"],"languages":["en"],"rights":["Copyright 2016 Dipanjan Das"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/98442","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Krein, Philip T."]},{"key":"dc:creator","label":"Author","values":["Das, Dipanjan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2017-09-29T17:57:13Z","2016-04-28","2016-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Electrical & Computer Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.S."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Differential Power Processing","Series-stacked power delivery","Series stacking","Bidirectional power converters","Light-load"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2016 Dipanjan Das"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/98442"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["A modern high-end multi-core microprocessor has very stringent power supply requirements. It can draw hundreds of amperes of current at supply voltages as low as 0.8 V. As the supply voltages keep decreasing, the power delivery to meet the supply requirements is becoming increasingly difficult and inefficient. However, the presence of multiple cores in the microprocessor offers us a way to power it at a higher voltage by series-stacking the cores. Differential power processing has been shown to be an efficient way to series-stack server loads. In this work we study the dynamics of the element-to-element DPP topology implemented with bi-directional buck-boost converters. Some of its dynamic drawbacks are pointed out and a topological modification to counter those drawbacks is proposed. We then develop a linear control to regulate processor core voltages in a series stack of 4 cores. A hysteretic control to accommodate light load modes in the bi-directional regulating converters is also discussed. Both the linear and the hysteretic controller are implemented successfully in hardware and efficiency improvement due to light-load modes is demonstrated.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-09-29 without embargo terms","The student, Dipanjan Das, accepted the attached license on 2016-04-25 at 16:13.","The student, Dipanjan Das, submitted this Thesis for approval on 2016-04-25 at 16:40.","This Thesis was approved for publication on 2016-04-28 at 10:43.","DSpace SAF Submission Ingestion Package generated from Vireo submission #9481 on 2017-09-29 at 11:25:03","Made available in DSpace on 2017-09-29T17:57:13Z (GMT). No. of bitstreams: 2 DAS-THESIS-2016.pdf: 14266075 bytes, checksum: dd1c6aa83c08e154ad9f7ecc78c8cd0a (MD5) LICENSE.txt: 4209 bytes, checksum: ad00c3658dac54fe1896f78b05a5641f (MD5) Previous issue date: 2016-04-28"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Voltage regulation of a series stacked system of digital loads by differential power processing"]}]}],"canonical_facts":{"dc:contributor":["Krein, Philip T."],"dc:creator":["Das, Dipanjan"],"dc:date":["2017-09-29T17:57:13Z","2016-04-28","2016-05"],"dc:description":["A modern high-end multi-core microprocessor has very stringent power supply requirements. It can draw hundreds of amperes of current at supply voltages as low as 0.8 V. As the supply voltages keep decreasing, the power delivery to meet the supply requirements is becoming increasingly difficult and inefficient. However, the presence of multiple cores in the microprocessor offers us a way to power it at a higher voltage by series-stacking the cores. Differential power processing has been shown to be an efficient way to series-stack server loads. In this work we study the dynamics of the element-to-element DPP topology implemented with bi-directional buck-boost converters. Some of its dynamic drawbacks are pointed out and a topological modification to counter those drawbacks is proposed. We then develop a linear control to regulate processor core voltages in a series stack of 4 cores. A hysteretic control to accommodate light load modes in the bi-directional regulating converters is also discussed. Both the linear and the hysteretic controller are implemented successfully in hardware and efficiency improvement due to light-load modes is demonstrated.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-09-29 without embargo terms","The student, Dipanjan Das, accepted the attached license on 2016-04-25 at 16:13.","The student, Dipanjan Das, submitted this Thesis for approval on 2016-04-25 at 16:40.","This Thesis was approved for publication on 2016-04-28 at 10:43.","DSpace SAF Submission Ingestion Package generated from Vireo submission #9481 on 2017-09-29 at 11:25:03","Made available in DSpace on 2017-09-29T17:57:13Z (GMT). No. of bitstreams: 2 DAS-THESIS-2016.pdf: 14266075 bytes, checksum: dd1c6aa83c08e154ad9f7ecc78c8cd0a (MD5) LICENSE.txt: 4209 bytes, checksum: ad00c3658dac54fe1896f78b05a5641f (MD5) Previous issue date: 2016-04-28"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/98442"],"dc:language":["en"],"dc:rights":["Copyright 2016 Dipanjan Das"],"dc:subject":["Differential Power Processing","Series-stacked power delivery","Series stacking","Bidirectional power converters","Light-load"],"dc:title":["Voltage regulation of a series stacked system of digital loads by differential power processing"],"dc:type":["text"],"thesis:degree_discipline":["Electrical & Computer Engr"],"thesis:degree_level":["Thesis"],"thesis:degree_name":["M.S."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:35Z"}