Bringing Robustness and Power Efficiency to Autonomous Energy Harvesting Microsystems

Autonomous devices that are self-powered by extracting their energy from their environment are a new opportunity for monitoring purposes. A multi-energy sources and multi-sensors microsystem targeting autonomous wireless sensor node applications is presented. Since the available energy is not constant over time and due to very low harvested power levels, an efficient energy and power management strategy is mandatory. In this paper, we propose to use the benefits of an event-based asynchronous controller to reduce the overall power consumption and bring voltage level robustness to the microsystem. The proposed architecture is energy-driven by detecting environmental energy events which are translated in data events to the controller, implemented in asynchronous logic. The data-driven controller dynamically reconfigures the power paths between sources and sensors to optimize the microsystem power efficiency. Compared to classical harvesting systems proposing a single power path through a battery, our proposal allows up a 40% power efficiency gain.