A Synchronized Switch Harvesting Rectifier With Reusable Storage Capacitors for Piezoelectric Energy Harvesting

Synchronized ac-dc rectifiers are widely used for energy rectification in piezoelectric energy harvesting (PEH), which have to employ a bulky inductor or some dedicated flying capacitors for high energy conversion efficiency. This article proposes a synchronized switch harvesting on shared capacitors (SSHSC) rectifier achieving synchronized voltage flipping without inductors or dedicated flying capacitors for PEH. The proposed SSHSC rectifier employs only three energy-storage capacitors with a specific capacitance ratio (3:3:1). These three capacitors mainly serve as storage capacitors; they can also be reused as flying capacitors for bias-flip operations. Thanks to the capacitor-sharing technique, this SSHSC rectifier takes a small volume and fewer I/O pads compared to prior SSHC rectifiers. This design was fabricated in a 180-nm BCD process, and the measured results show 78% voltage flipping efficiency and 7.58 $\times$ power enhancement.

Automated summary

This article proposes a synchronized switch harvesting on shared capacitors (SSHSC) rectifier for piezoelectric energy harvesting without the need for bulky inductors or dedicated flying capacitors. The SSHSC rectifier utilizes three energy-storage capacitors with a specific capacitance ratio, serving as both storage and flying capacitors. The capacitor-sharing technique enables a smaller volume and fewer I/O pads compared to prior designs.