A Parallel-SSHI Rectifier for Piezoelectric Energy Harvesting of Periodic and Shock Excitations

Piezoelectric harvesters are capable of generating energy out of ambient vibrations. Dedicated interface circuits can significantly increase the harvesting capabilities compared with passive rectifiers. This paper presents an autonomous piezoelectric energy harvesting system in a 0.35-μm CMOS process. The implemented interface is based on the parallel-SSHI technique and can harvest from periodic and shock excitations. Regular operation is enabled for input voltages as low as 670 mV. It extracts up to 6.81 times more power compared with an ideal full-bridge rectifier depending on the generator characteristics and excitation conditions. The device is capable of cold startup and provides a stable output voltage for powering an application.