A Full-Wave Rectifier for Interfacing with Multi-Phase Piezoelectric Energy Harvesters

This paper describes an asynchronous full-wave rectifier for use with a multiple-electrode disk-shaped piezoelectric generator. By using quarter-circle shaped electrodes, similar to an ultrasonic motor, multiple output voltage phases are obtained from a single resonating piezoelectric disk. Two-electrode transducer outputs are often rectified using a full-wave diode bridge rectifier, which requires a significant voltage drop between input and output, decreasing the rectifier's voltage efficiency. Previous asynchronous rectifiers use MOS switches to avoid the diode drop, however they lack the ability to efficiently rectify the multiple output phases generated from a disk-shaped transducer. Other CMOS rectifiers need two input waveforms that are equal and opposite, which a piezoelectric transducer may not generate for many input vibrations.