[Editors] Team develops energy-efficient microchip

[Elizabeth Thomson]

MIT News Office
Massachusetts Institute of Technology
Room 11-400
77 Massachusetts Avenue
Cambridge, MA  02139-4307
Phone: 617-253-2700
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Team develops energy-efficient microchip

--Could lead to longer-lasting, self-charging cellphones, more

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For Immediate Release
MONDAY, FEB. 4, 2008
Contact: Elizabeth A. Thomson, MIT News Office -- Phone: 617-258-5402  
-- Email: thomson at mit.edu

PHOTO AVAILABLE

CAMBRIDGE, Mass.-- Researchers at MIT and Texas Instruments have  
unveiled a new chip design for portable electronics that can be up to  
10 times more energy-efficient than present technology. The design  
could lead to cell phones, implantable medical devices and sensors  
that last far longer when running from a battery.

The innovative design will be presented Feb. 5 at the International  
Solid-State Circuits Conference in San Francisco by Joyce Kwong, a  
graduate student in MIT's Department of Electrical Engineering and  
Computer Science (EECS).

Kwong carried out the project with MIT colleagues Anantha  
Chandrakasan, the Joseph F. and Nancy P. Keithley Professor of  
Electrical Engineering, and EECS graduate students Yogesh Ramadass  
and Naveen Verma. Their Texas Instruments (TI) collaborators are  
Markus Koesler, Korbinian Huber and Hans Moormann. The team  
demonstrated the ultra-low-power design techniques on TI's MSP430, a  
widely used microcontroller. The work was conducted at the MIT  
Microsystems Technology Laboratories, which Chandrakasan directs.

The key to the improvement in energy efficiency was to find ways of  
making the circuits on the chip work at a voltage level much lower  
than usual, Chandrakasan explains. While most current chips operate  
at around one volt, the new design works at just 0.3 volts.

Reducing the operating voltage, however, is not as simple as it might  
sound, because existing microchips have been optimized for many years  
to operate at the higher standard-voltage level. “Memory and logic  
circuits have to be redesigned to operate at very low power supply  
voltages,” Chandrakasan says.

One key to the new design, he says, was to build a high-efficiency DC- 
to-DC converter-which reduces the voltage to the lower level-right on  
the same chip, reducing the number of separate components. The  
redesigned memory and logic, along with the DC-to-DC converter, are  
all integrated to realize a complete system-on-a-chip solution.

One of the biggest problems the team had to overcome was the  
variability that occurs in typical chip manufacturing. At lower  
voltage levels, variations and imperfections in the silicon chip  
become more problematic. “Designing the chip to minimize its  
vulnerability to such variations is a big part of our strategy,”  
Chandrakasan says.

So far the new chip is a proof of concept. Commercial applications  
could become available “in five years, maybe even sooner, in a number  
of exciting areas,” Chandrakasan says. For example, portable and  
implantable medical devices, portable communications devices and  
networking devices could be based on such chips, and thus have  
greatly increased operating times. There may also be a variety of  
military applications in the production of tiny, self-contained  
sensor networks that could be dispersed in a battlefield.

In some applications, such as implantable medical devices, the goal  
is to make the power requirements so low that they could be powered  
by “ambient energy,” Chandrakasan says-using the body's own heat or  
movement to provide all the needed power. In addition, the technology  
could be suitable for body area networks or wirelessly enabled body  
sensor networks.

“Together, TI and MIT have pioneered many advances that lower power  
in electronic devices, and we are proud to be part of this  
revolutionary, world-class university research,” said Dr. Dennis  
Buss, chief scientist at Texas Instruments. “These design techniques  
show great potential for TI future low-power integrated circuit  
products and applications including wireless terminals, battery- 
operated instrumentation, sensor networks and medical electronics.”

The research was funded in part by a grant from the U.S. Defense  
Advanced Research Projects Agency.

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Written by David Chandler, MIT News Office