Energy-efficient microchip provides fresh slate for students in India

Margaret W. Bushee, margaret.bushee@laurin.com

According to the District Information System for Education, which tracks statistics on education in rural India, nearly 106 million schoolchildren do not have access to electricity, and more than 417,000 attend primary schools with fewer than three teachers. However, thanks to a new computer chip that uses 30 times less power and runs seven times faster than any other microchip available, many students soon will be the beneficiaries of a solar-powered electronic teaching tool called the I-slate, which will teach math through a visually based curriculum.

The microchip technology, invented by Rice University computer science professor Krishna V. Palem, along with doctoral student Lakshmi N.B. Chakrapani, was driven largely by the downside of Moore’s law. This trend was described in 1965 by Intel Corp. co-founder Gordon Moore, who observed that the number of transistors that can be placed on an integrated circuit increases exponentially. The density creates signal “noise” that engineers have compensated for with increased voltage, which overrides the noise to ensure accurate calculations. However, this solution raises the energy consumption and generates more heat.

Theoretical foundations

About six years ago, with the goal of addressing impediments to the progress of semiconductor technology – including the high energy consumption of transistors – Palem revisited the principles of thermodynamics and began laying the theoretical foundations for a new chip. His team worked in conjunction with the Institute for Sustainable Nanoelectronics at Nanyang Technological University in Singapore, whose researchers were involved with circuit design, simulation and testing, as well as with chip testing and measurement.

The new chip, called probabilistic complementary metal oxide semiconductor, or PCMOS, is made of silicon, but its design is based on what the researchers call probabilistic Boolean logic rather than on the traditional Boolean logic that all digital computers have used to date. In probabilistic Boolean logic, which renders less precise data but costs less in terms of energy, the key operators such as AND, OR and NOT function with less reliability but with an accuracy that is suitable for applications such as the I-slate.

The user-friendly technology, compatible with CMOS technology, will have widespread use in signal processing and graphics applications, Palem said. The chip should enable the development of ultralow-energy devices, such as a cell phone that needs infrequent charging and a low-cost DVD player. His team also envisions bioprosthetic applications, including a completely in-canal hearing aid and a silicon retina.

Palem expects that the I-slate, which his group is developing, along with its curriculum, will be tested beginning in the spring of 2010 and that evaluating both the technology and content should take about a year. The outreach team he is leading includes educational technologists from the International Institute of Information Technology in Hyderabad, India, and the Indian nonprofit Villages in Development and Learning Foundation in the southern Mahboobnagar district. Besides providing schoolchildren with I-slates, the researchers’ purpose is to create a self-sustaining economic model for disseminating them in the future.