A Flipping-Input Interface Circuit with Hybrid Storage Component for Piezoelectric Energy Harvesting

The chapter delves into the challenges of traditional battery power supplies in meeting the demands of the Internet of Things (IoT), highlighting piezoelectric energy harvesting (PEH) as a promising alternative. It examines the limitations of existing interface circuits, particularly the energy loss associated with flipping charge loss in piezoelectric harvesters. The core innovation presented is the Flipping-Input Synchronous Switch Harvesting on Inductor and Capacitor (FI-SSHIC) structure, which optimizes the flipping process to achieve a remarkable 93.5% flipping efficiency. This is accomplished using microhenry-level inductors and capacitors equal to the parasitic capacitance of the piezoelectric harvester, significantly reducing the size of external passive devices. The chapter provides a detailed analysis of the system's architecture, including the switch array, buck-boost module, and control section, which collectively enhance the efficiency and output power of the energy harvesting system. Simulation results demonstrate a 28.3% and 53.4% increase in output power compared to existing Synchronous Switch Harvesting on Capacitor (SSHC) and Synchronous Switch Harvesting on Inductor (SSHI) structures, respectively. The chapter also compares the performance of the proposed FI-SSHIC with previously published piezoelectric energy harvesting chips, underscoring its superior efficiency and reduced component size. Overall, the chapter offers a compelling exploration of advanced interface circuits for piezoelectric energy harvesting, providing valuable insights for researchers and engineers seeking to improve the efficiency and reliability of energy harvesting technologies.