A solar cell the size of a stamp. That's all Intel Corp. researchers needed to power a computer processor that could hold a tantalizing vision for the low-power chips of the future.
The company showed off the feat this week at its annual developer conference in San Francisco.
The achievement was less about the fact the chip ran on solar power and more about how Intel employees were able to create a chip that ran on little more than the power needed to turn on its transistors, the so-called "threshold" voltage.
Intel's chief technology officer, Justin Rattner, said the experimental processor was 5 times more energy-efficient than today's processors. But he emphasized that it is nowhere near ready for prime time.
The chip was based on a redesign of a Pentium processor that's more than a decade old, and the underlying technology was so dated that employees needed to scour eBay for a motherboard to plug the chip into, he said.
The decision to base their work on an old chip design speaks to the difficulty of the engineering challenge.
The Pentium had a vastly simpler design than today's chips, which made the task of redesigning nearly all of the circuits to work right at such low power a more manageable goal for a small team of researchers, Rattner said.
The point of the research was to demonstrate that extreme power savings are possible.
"People these days will kill for another 15 or 20 minutes of battery life, and here you're saying you can improve battery life by a factor of 5 or 10," Rattner said in an interview.
The chip itself was the only part of Intel's demonstration computer that was solar-powered. The computer itself, which was running Windows, ran on regular electricity.
The concept of a solar-powered computer isn't new, and there are already a slew of solar chargers for consumer electronics. But the promise of Intel's research is that solar-powered processors could one day start tackling small projects, such as powering small sensors that communicate wirelessly with computers, and potentially be incorporated into more complicated computers to tackle bigger challenges.
"The applications are almost endless for it," Rattner said.