Voltage regulation of a series stacked system of digital loads by differential power processing

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.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2016

Author dc:creator

• Das, Dipanjan

Contributors dc:contributor

• Krein, Philip T.

• Differential Power Processing
• Series-stacked power delivery
• Series stacking
• Bidirectional power converters
• Light-load

Statement dc:rights

• Copyright 2016 Dipanjan Das

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/94164

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/94164