[AI] An energy-efficient microchip with myriad uses

renuka warriar erenuka at gmail.com
Thu Feb 14 07:17:29 EST 2008

Date:14/02/2008 URL: http://www.thehindu.com/thehindu/seta/2008/02/14/stories/2008021450051500.htm 

Sci Tech 

An energy-efficient microchip with myriad uses 

Embedded medical devices based on such chips will consume only a tenth of the current power

Commercial applications could become available in five years or, perhaps, even sooner

A cell phone dying at a crucial moment, a digital camera that warns of low power at a perfect photo opportunity or a laptop inopportunely running out of
juice - many of us have had such vexing experiences firsthand. 

Researchers at the Massachusetts Institute of Technology and Texas Instruments (TI) have designed a chip, ten times more energy-efficient than existing
ones, to keep portable devices going longer. 

Because of the lower power consumption, the batteries of these mobile devices and vital medical implants do not have to be recharged or replaced as frequently
as they are now.

Although users tend to be excited by new features on gadgets, every additional feature - like the ability to watch video clips or take snapshots on a cell
phone - puts a burden on the battery's limited power.

Clearly, a new approach to chip design was in order because saddling such portable devices with bigger and better batteries can only take us so far. In
such devices, the key to turn down power consumption was the voltage, says Anantha Chandrakasan, Director of MIT's Microsystems Technology Laboratories
and the Joseph F. and Nancy P. Keithley Professor of Electrical Engineering. 

The longevity of the battery comes from the chip's lower voltage requirement. 

The operating voltage for circuits on a chip is typically 1 volt but the new chip can operate at just 0.3 volts. An important feature of this new chip's
design is a high-efficiency DC-to-DC converter - akin to an in-situ step-down transformer - that slashes the input voltage to one third of its strength.

Huge implications 

Traditionally, the circuits on such chips have been optimised to operate at a supply voltage of around 1 volt. Scaling down the supply voltage has huge

Memory and logic circuits had to be redesigned to operate at 0.3 volts, a voltage low enough to disrupt the chip's very functionality, says Chandrakasan,
the leader of the chip's re-architecture team. 

Besides, the team also had to overcome the variability inherent in chip manufacturing. At this lower supply voltage, variations and imperfections in the
silicon chip could throw the electronic circuit out of whack; in the binary system what was registered as 1 could become 0 and vice versa. Designing the
chip to minimize its vulnerability at the new voltage was a huge challenge. 

The team demonstrated an ultra-low-power version of TI's MSP430, a widely used microcontroller. "These design techniques show great potential for TI's future
low-power integrated circuit products and applications including wireless terminals, battery-operated instrumentation, sensor networks and medical electronics,"
says Dr. Dennis Buss, chief scientist at Texas Instruments.

Networking devices 

Portable and embedded medical devices, such as hearing aids and retinal implants, communications and networking devices based on such chips will consume
only a tenth of the current power. 

A person who now watches short clips on a cell phone, for instance, can view longer videos without the need to recharge. There could also be a variety of
military applications in the production of tiny, self-contained sensor networks that could be dispersed in a battlefield. 

Eventually, in medical devices the idea is to make the power requirement so low that they could run on 'ambient energy' - using the body's own heat or movement
to provide the requisite power. 

The ultimate goal is to design a generator on a chip, eliminating the need for a battery, says Chandrakasan. 


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