A PhD student at the University of Eindhoven has designed a microcontroller that can optimise energy harvesting for IoT devices.

The IoT connects billions of devices that sense, process and transmit data across diverse applications, including healthcare, environmental monitoring and industrial automation. Yet, most IoT devices rely on batteries, which limit their lifetime, require regular maintenance, and pose environmental concerns due to production and disposal.

In her PhD research, Shima Sedighiani investigated how to enable energy-autonomous IoT devices that operate reliably by harvesting ambient energy from the environment. Because such energy sources are typically weak and highly variable, her work focused on developing a microcontroller optimised for efficient operation under intermittent and low-power conditions.

The low-leakage microcontroller has integrated power management designed through a hardware–software co-design approach. Her research presents three key innovations: a fully digital voltage monitor that estimates available energy with low power overhead and a wide operating range; a data-retention flip-flop that preserves data during power interruptions with record-low leakage of 380 femtowatts; and a dual-path power management architecture that separates energy storage for active and idle modes, eliminating the need for voltage regulators and reducing energy losses.

The system was fabricated using 28nm FD-SoI (full depleted silicon-on-insulator) technology and achieved a 4400-fold reduction in leakage power compared with conventional microcontrollers. In one representative measurement scenario, the conventional system required its backup battery for approximately 85% of its operating time. By contrast, Sedighiani’s design operated entirely on harvested energy, demonstrating its potential for true energy autonomy.

This research offers a holistic and scalable method for sustainable, maintenance-free IoT systems powered solely by ambient energy. By combining low-power circuit techniques with intelligent energy management, it contributes to the development of long-lasting, environmentally responsible electronics.

These innovations could lay the foundation for future smart and autonomous applications that are not only technologically robust but also sustainable.

For more on Sedighiani’s paper, go to research.tue.nl/nl/publications/ultra-low-leakage-microcontroller-with-power-control-for-sustaina/. She studied at the department of electrical engineering at the University of Eindhoven (www.tue.nl) in the Netherlands. Her supervisors were Jose Pineda de Gyvez, Pieter Harpe and Roel Jordans.