Design of a Self-Investing Circuit for Synchronous Electrical Charge Extraction for Piezoelectric Energy Harvester

This paper focuses on harvesting piezoelectric energy using the Synchronous Electrical Charge Extraction (SECE) as the interface between the Piezoelectric transducer and the load. Though SECE is flexible because there is no need to do impedance matching, it does not extract high power in comparison with other nonlinear methods of energy harvesting. An additional method must be integrated into the SECE to increase extracted power. In this study, a Self-Investing circuit tailored to TSMC 180nm IP6M CMOS technology was designed, simulated, and integrated into a Synchronous Electrical Charge Extraction (SECE) circuit for enhanced power extraction from piezoelectric transducers. The proposed SI-SECE core layout occupies a modest area of 183.675 μm × 213.72 μm. The proposed SI-SECE circuit harvests 2.14 μW, indicating an increase of 11.2% compared to conventional SECE, which yields 1.90 μW under similar conditions with a 250 Hz PEH excitation frequency and 1.08 V piezoelectric open circuit voltage amplitude. Furthermore, proposed circuit achieved a maximum output power of 6.42 μW and a peak power conversion efficiency of 69.7%, attributed to effective charge investment and the management of conduction and switching losses on investing transistors.