Fast-Convergence Self-Adjusting SECE Circuit With Tunable Short-Circuit Duration Exhibiting 368% Bandwidth Improvement

The harvesting frequency bandwidth (HBW) of a resonant-based electromechanical harvester is inherently limited by its quality factor. Electrical tuning of the resonant frequency leveraged by a significant electromechanical coupling is a promising approach to enhance the HBW and paves the way toward industrialization of robust vibration energy harvesting system. However, it remains challenging to design a self-powered harvesting IC that includes self-tuning capabilities, especially at low vibration amplitude. This letter describes the shorted synchronous electrical charge extraction (SSECE) strategy and proposes a dedicated self-powered integrated circuit, including power stage, sensors to sequence the harvesting phases, and power sensing. An on-chip tracker dynamically maximizes the harvesting power when the piezoelectric-based harvester characteristics or excitation frequency shifts. The experimental results show a 368% HBW enlargement with the highest convergence FoM (0.213) and the lowest power-peak frequency compared to the prior art.