Establishing a network of environmental sensors all over a forest is one thing. Keep the circuits properly powered is another. Imagine traipsing around the forest to replace 600 batteries every week! Makers need systems with ultra-low power sensors that can efficiently harvest energy from the environment.
Researchers at MIT recently presented their work on such a system at the Symposia on VLSI Technology and Circuits. The team’s power converter chip is extremely efficient, harvesting more than 80 percent of the energy trickling into it, even when tiny solar cells were used. Similar systems have only been able to harvest 50 percent or less. Another advantage: this new system can charge a battery and directly power a circuit. Previous systems could only do one or the other.
“We still want to have battery-charging capability, and we still want to provide a regulated output voltage,” Dina Reda El-Damak said in a statement. Dina was lead author on a paper about the system and is also a MIT graduate student in electrical engineering and computer science. “We need to regulate the input to extract the maximum power, and we really want to do all these tasks with inductor sharing and see which operational mode is the best. And we want to do it without compromising the performance, at very limited input power levels — 10 nanowatts to 1 microwatt — for the Internet of things.”