Differential power processing for series-stacked processors

power;switched-capacitor

Stillwell, Andrew R ; Pilawa ; Robert

关键词: power;    switched-capacitor;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/88081/STILLWELL-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

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 switchingfrequencies from 250 kHz to 2 MHz. Finally, the reliability of a series-stacked system is compared to an electrically parallel system.