6. Could this temperature sensor reduce power consumption in medical devices?A new temperature sensor that runs at 113 pW could make wearables and even implantable medical devices less power dependent, according to research from the University of California at San Diego.
The temperature sensor, developed by electrical engineers at UCSD, uses about 628 times lower power than state-of-the-art power sources and is 10 billion times smaller than a watt. Considered “near zero power,” the engineers suggest that the temperature sensor could extend battery life in a variety of wearable or implantable devices that measure body temperature. It could able be used to create a new class of devices that is capable of harvesting its energy from the body or surrounding environments.
Temperature sensors on healthcare devices have power requirements of as low as tens of nanowatts. The new approach reduces power in the current source and the conversion temperature to a digital readout, making temperature sensors up at 628 times less power.
Researchers used “gate leakage” transistors to build an ultra-low power current source. Usually, gate leakage is a problem in microprocessors and precision analog circuits because the gate material is too thin and can’t block electrons from leaking through. But the researchers are using that to their advantage.
Using the low-power source, the researchers created a way to digitize temperature without consuming a lot of energy. Normally, as temperature changes, so does its resistance. Then they measure the resulting voltage and convert it to its corresponding temperature using a high power analog to digital converter. In the low-power method, researchers can directly digitize temperature by using two ultra-low power current sources: one that charges a capacitor in a time frame regardless of temperature and one that charges at a rate that changes with temperature. The lower the temperature, the slower the charge. The higher the temperature, the faster the charge.