MIT scientists have developed a new electronic chip that could mark a critical first step towards battery-free systems. The potent chip is able to operate on extremely low levels of power, and it can harvest energy from a range of sources – including sunlight, heat and environmental vibrations – at the same time, meaning it won’t go offline if one energy source cuts out.
The team developing the new chip is led by MIT professor Anantha Chandrakasan. He describes the new energy-combining chip in the IEEE Journal of Solid-State Circuits, stating that the team’s goal is to create a chip that achieves efficient use of multiple power sources in a single device. By doing so, it would not be reliant on any one source.
“Energy harvesting is becoming a reality,” says Chandrakasan, the Keithley Professor of Electrical Engineering and head of MIT’s Department of Electrical Engineering and Computer Science. “The key here is the circuit that efficiently combines many sources of energy into one.”
Most computer systems that generate electricity from environmental factors focus on one particular source or switch among them in order to take advantage of whichever one is generating the most energy at a given moment, but the MIT team believes that they can make use of a range of energy sources at the same time
“We extract power from all the sources,” says doctoral student Saurav Bandyopadhyays. “At one particular instant, energy is extracted from one source by our chip, but the energy from other sources is stored in capacitors and later picked up, so none goes to waste.”
The system uses an innovative dual-path architecture. Typically, power sources would be used to charge up a storage device, such as a battery or a supercapacitor, which would then power an actual sensor or other circuit. But in this control system, the sensor can either be powered from a storage device or directly from the source, bypassing the storage system altogether.
“That makes it more efficient,” Bandyopadhyay says. The chip uses a single time-shared inductor, a crucial component to support the multiple converters needed in this design, rather than three separate ones.”
In a statement, David Freeman, chief technologist for power-supply solutions at Texas Instruments, said: “The work being done at MIT is very important to enabling energy harvesting in various environments. The ability to extract energy from multiple different sources helps maximize the power for more functionality from systems like wireless sensor nodes.”