Chip promises 50% cut in mobile power consumption

Harvard researcher offers device that shuts off power to parts of core not in use

A Harvard researcher is developing a technology that could cut power to parts of a microprocessor that are not in use, saving energy and improving the efficiency of the device by as much as 50%.

Harvard graduate student Wonyoung Kim says his on-chip, multi-core voltage regulator (MCVR) addresses what amounts to a mismatch between power supply and demand.

More on energy:  10 hot energy projects that could electrify the world 

"The multi-core voltage regulator responds almost instantaneously to changes in power demand from each core of the processor."  As a result, the power supply matches the demand more closely, conserving energy, according to a Harvard release.  "The on-chip design means that the power supply can be managed not just for each processor chip, but for each individual core on the chip. The short distance that signals then have to travel between the voltage regulator and the cores allows power scaling to happen quickly - in a matter of nanoseconds rather than microseconds - further improving efficiency."

The idea is pretty simple, the device basically shuts off parts of the CPU that are not being used.  "For example, a graphics processor element is heavily used when playing a game, but not used when listening to music. Further, within a game, the graphics processor is more heavily used in scenes with a lot of action when compared to relatively inactive scenes. Consequently, utilization of each processing element in the processor chip changes dramatically across user activities, but the voltages dedicated to each element does not.  The amount each element is utilized changes based on the application and fluctuates over time. However, each processing element receives the same voltage regardless of utilization," according to the university.

In current handset processors, electrical power is wasted because multiple processing elements share a single voltage and that voltage lacks the ability to rapidly fluctuate to meet changing processing demand. The MCVR can work at 2.4 volts and can output anywhere from 1.4 volts to 0.4 volts depending on the current computing demands rapidly by increasing or decreasing voltage in about 20 nanoseconds. 

Although Kim estimates that the greatest demand for the MCVR could be in the mobile phone market, the device would also have applications in other computing scenarios. Used in laptops, the MCVR might reduce the heat output of the processor, which is currently one barrier to making slimmer notebooks. In stationary scenarios, the rising cost of powering servers of ever-increasing speed and capacity could be reduced, Kim states.

According to Harvard, Kim has obtained a provisional patent for the MCVR with his Ph.D. co-advisers at SEAS, Gu-Yeon Wei, Gordon McKay Professor of Electrical Engineering, and David Brooks, Gordon McKay Professor of Computer Science, who are coauthors on the paper he recently presented at the Institute of Electrical and Electronics Engineers' (IEEE) International Solid-State Circuits Conference (ISSCC).

Follow Michael Cooney on Twitter: nwwlayer8  

Layer 8 Extra

Check out these other hot stories:

NASA recruiting sponsors for new high-tech competitions

FBI activates electronic posse to go after serial rapist

US House crimps consumer safety database money

FBI: Internet crime high but types of misdeeds changing

Is IT skills gap keeping companies from hiring?

Former Avaya chief D'Ambrosio takes reigns at Sears

Want your own, sort of, personal submarine?

NASA wants spacecraft designed for Mars return trip

NASA satellite primed for first ever Mercury orbit

Join the Network World communities on Facebook and LinkedIn to comment on topics that are top of mind.

Copyright © 2011 IDG Communications, Inc.