CUED Publications database

Energy recovery from high-frequency clocks using DC-DC converters

Alimadadi, M and Sheikhaei, S and Lemieux, G and Mirabbasi, S and Dunford, W and Palmer, P (2008) Energy recovery from high-frequency clocks using DC-DC converters. Proceedings - IEEE Computer Society Annual Symposium on VLSI: Trends in VLSI Technology and Design, ISVLSI 2008. pp. 162-167.

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Abstract

Large digital chips use a significant amount of energy to distribute a multi-GHz clock. By discharging the clock network to ground every cycle, the energy stored in this large capacitor is wasted. Instead, the energy can be recovered using an on-chip DC-DC converter. This paper investigates the integration of two DC-DC converter topologies, boost and buck-boost, with a high-speed clock driver. The high operating frequency significantly shrinks the required size of the L and C components so they can be placed on-chip; typical converters place them off-chip. The clock driver and DC-DC converter are able to share the entire tapered buffer chain, including the widest drive transistors in the final stage. To achieve voltage regulation, the clock duty cycle must be modulated; implying only single-edge-triggered flops should be used. However, this minor drawback is eclipsed by the benefits: by recovering energy from the clock, the output power can actually exceed the additional power needed to operate the converter circuitry, resulting in an effective efficiency greater than 100%. Furthermore, the converter output can be used to operate additional power-saving features like low-voltage islands or body bias voltages. ©2008 IEEE.

Item Type: Article
Subjects: UNSPECIFIED
Divisions: Div B > Electronics, Power & Energy Conversion
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 12:36
Last Modified: 28 Nov 2014 19:05
DOI: 10.1109/ISVLSI.2008.102