Engineers at the University of Michigan have developed a new microchip that
uses 30,000 times less power in sleep mode and ten times less power when
working than other comparable chips on the market.
The processor -- called The
Phoenix Processor -- set a low-power record by consuming only 30 picowatts
when in sleep mode. A picowatt is one-trillionth of a watt. The researchers say
that theoretically the low power requirements of the chip when in sleep mode
would allow a standard watch battery to power the processor for 263 years.
The processor isn’t any smaller physically than other chips on the market,
which routinely measure the same one square millimeter size or even smaller.
What is unique about the Phoenix is that its thin-film battery is the same size
as the Phoenix chip.
In most cases the batteries used with processors are much larger than the
processor itself making the overall size of the device much larger. Professor
David Blaauw of the Department of Electrical Engineering and Computer Science
said in a statement, “Low power consumption allows us to reduce battery size
and thereby overall system size. Our system, including the battery, is
projected to be 1,000 times smaller than the smallest known sensing system
today. It could allow for a host of new sensor applications."
The engineers see the Phoenix chip being used in devices like medical
implants, environment monitors and surveillance equipment.
To get the huge power savings the engineers employed old processor
technology and used much smaller power gates that let smaller amounts of
electricity leak past the power gates when in sleep mode. The trade off for the
much smaller power gates is that they severely limit processing power of the
chip.
To remedy the performance loss the researchers run the Phoenix at a higher
operating voltage of about 20% greater than needed when the chip is awake.
Despite the higher power sent to the chip when awake it still consumes only 0.5
volts. By comparison the Intel
Atom processor needs 1.1V to operate.
The chip defaults to sleep mode and is woke up by a low-power timer every
ten minutes for 1/10th of a second to run a set of 2,000 instructions. These
instructions include checking the sensor for new data, processing the data and
storing it before going back to sleep.