Die micrograph of the fully integrated DC-DC converter chip. Image courtesy of Wonyoung Kim.
To promote energy-efficient multitasking, Harvard graduate student Wonyoung Kim has developed and demonstrated a new device with the potential to reduce the power usage of modern processing chips.
The advance could allow the creation of “smarter” smartphones, slimmer laptops, and more energy-friendly data centers.
Kim’s on-chip, multi-core voltage regulator (MCVR) addresses what amounts to a mismatch between power supply and demand.
If you’re listening to music on your MP3 player, you don’t need to send power to the image and graphics processors at the same time
Essentially a DC-DC converter, the MCVR can take a 2.4-volt input and scale it down to voltages ranging from 0.4 to 1.4V. Built for speed, it can increase or decrease the output by 1V in under 20 nanoseconds.
The MCVR also uses an algorithm to recognize parts of the processor that are not in use and cuts power to them, saving energy. Kim says it results in a longer battery life (or, in the case of stationary data centers, lower energy bills), while providing the same performance.
The on-chip design means that the power supply can be managed not just for each processor chip, but for each individual core on the chip. The short distance that signals then have to travel between the voltage regulator and the cores allows power scaling to happen quickly—in a matter of nanoseconds rather than microseconds—further improving efficiency.
The multi-core voltage regulator responds almost instantaneously to changes in power demand from each core of the processor. As a result, the power supply matches the demand more closely, conserving energy. Image courtesy of Wonyoung Kim.