New IoT chip could make sensors in the body last much, much longer

20 Feb 2017

Image: Gansstock/Shutterstock

IoT researchers are constantly trying to make the devices that gather and send data more energy efficient. One team has made a major breakthrough.

Technologies like micropower, which can create and store electric energy in the smallest of devices, is set to become crucial in a future where billions of connected internet of things (IoT) devices are sending reams and reams of information to each other.

While major steps have been achieved to make the gathering of this data as energy efficient as possible, ‘waking up’ only when needed, the same can’t be said for sending that information to distant radio receivers.

But now, researchers from MIT’s Microsystems Technology Laboratories have revealed a new method of power conversion that could drastically improve a device’s ability to remain efficient by as much as 50pc.

The step down converter design means that a device’s output voltage is less than the amount of energy being put into it, by taking input voltages of between 1.2 and 3.3 volts and reducing them by between 0.7 and 0.9 volts.

“The way these power converters work, it’s not based on a continuous flow of energy,” said Arun Paidimarri, who was involved in the research.

“It’s based on these packets of energy. You have these switches, and an inductor and a capacitor in the power converter, and you basically turn on and off these switches.”

From sensors in the body to energy-harvesting devices

Even when a device is not drawing current from a converter, between one and a few hundred packets of energy per second will be released, but when a radio signal is being transmitted, this increases to around 1m packets each second.

To accommodate such a range of outputs, the average converter will perform at this higher rate. This does little to drain the power of a standard device, but for IoT, it becomes unsustainable.

The MIT team created a converter on a chip that features a variable clock, which can run the switch controllers at a wide range of rates, resulting in the 50pc reduction in power consumed during downtime.

This breakthrough could pave the way for a future of sustainable electronics within the human body, as well as new types of energy-harvesting sources.

“This work pushes the boundaries of the state of the art in low-power DC-DC converters,” said Yogesh Ramadass, director of power management research at Texas Instruments’ Kilby Labs.

Colm Gorey was a senior journalist with Silicon Republic