Power conversion and integrated circuit architecture for high voltage piezoelectric energy harvesting

Using harvesting energy to extend Wireless Sensor Nodes (WSN) operating life or even supply them, has become a topic of growing interest over the last decades. This paper presents the architecture of a fully autonomous Integrated Circuit which efficiently harvests energy from low frequency mechanical stresses. This circuit uses a high voltage piezoelectric transducer and provides energy to a storage element (battery or capacitor) at lower voltage (2.8 to 3.4V). We propose an innovative way to extract the electrostatic energy by using a modified Flyback topology and multiple magnetic transfers. Measurements show that our solution increases the energy transfer with a gain of 15% compared to the classical technique. We show that this work improves the efficiencies of both power and control stages. Finally, the control circuit of the Flyback converter will perform a self-starting operation from an empty energy storage element and is currently being designed in AMS0.35 CMOS technology.