Temperature sensor to extend battery life

1 min read

A temperature sensor that runs on 113pW of power has been developed by electrical engineers at the University of California San Diego as part of their work boosting energy efficiencies of individual parts of an integrated circuit to reduce the power requirement of the system as a whole.

The sensor could help extend the battery life of wearable or implantable devices that monitor body temperature, smart home monitoring systems, IoT devices and environmental monitoring systems.

According to the researchers, the technology could also enable a new class of devices that could be powered by harvesting energy from low power sources, such as the body or the surrounding environment.

"Our vision is to make wearable devices that are so unobtrusive that users are virtually unaware that they're wearing them. Our near-zero-power technology could one day eliminate the need to ever change or recharge a battery," said electrical engineering professor Patrick Mercier.

The researchers approach involved minimising power in two domains: the current source and the conversion of temperature to a digital readout.

The researchers built an ultra-low power current source using gate leakage transistors. "Many researchers are trying to get rid of leakage current, but we are exploiting it to build an ultra-low power current source," said PhD student Hui Wang.

Using these current sources, the research team developed an innovative system to digitise temperature directly and save power.

The temperature sensor is integrated into a small chip measuring 0.15 × 0.15mm2 and operates at temperatures ranging from -20 to 40°C.