Design, Fabrication and Characterization of a Piezoelectric Microgenerator Including a Power Management Circuit

We report in this paper the design, fabrication and experimental characterization of a piezoelectric MEMS microgenerator. This device scavenges the energy of ambient mechanical vibrations characterized by frequencies in the range of 1 kHz. This component is made with Aluminum Nitride thin film deposited with a CMOS compatible process. Moreover we analyze two possible solutions for the signal rectification: a discrete doubler-rectifier and a full custom power management circuit. The ASIC developed for this application takes advantage of diodes with very low threshold voltage and therefore allows the conversion of extremely low input voltages corresponding to very weak input accelerations. The volume of the proposed generator is inferior to 1mm and the generated powers are in the range of 1μW. This system is intended to supply power to autonomous wireless sensor nodes.