A 0.25-μm HV-CMOS Synchronous Inversion and Charge Extraction Interface Circuit with a Single Inductor for Piezoelectric Energy Harvesting

This paper presents an on-chipSynchronous Inversion and Change Extraction (SICE) interface circuit, which combines the advantages of both the Synchronous Switch Harvesting on Inductor (SSHI) and Synchronous Electric Charge Extraction (SECE) interface circuits while utilizing a shared inductor. The SICE employs a bias-flip operation, similar to the SSHI, by inverting the piezoelectric voltage at each extremum multiple times to achieve higher power gain. Subsequently, SICE transfers all energy in Piezoelectric Harvester to the output capacitor, similar to the harvesting operation used in an SECE, thereby making the transferred energy independent of the loading impedance. A prototype AC-DC converter with the proposed SICE interface circuit was fabricated in a TSMC 0.25-μm process. Experimental results demonstrate an output power (POUT) of 130μW when the piezoelectric voltage (VPZ) is 10V. The SICE interface circuit has been theoretically and experimentally shown to harvest more than 624% compared to the conventional full-bridge rectifier, validating its superior performance.