Extensible Multi-Input Synchronous Electronic Charge Extraction Circuit Based on Triple Stack Resonance for Piezoelectric and Thermoelectric Energy Harvesting

At present, research on interface circuits for environmental energy harvesting is mainly carried out around a single transducer. However, rich ambient energy sources can be harvested with multiple transducers. Hence, in this article, extensible multi-input synchronous electronic charge extraction (EMI-SECE) interface circuit based on triple-stack LC resonance for piezoelectric and thermoelectric energy harvesting is proposed. proposed EMI-SECE interface circuit can simultaneously extract energy from multiple piezoelectric transducers (PZTs) and thermoelectric generators when the peak open-circuit voltage of the PZTs is detected by the passive peak detectors. Theoretical analysis and experiments verify the effectiveness of the circuit. The experimental results show that the proposed EMI-SECE circuit can harvest energy from two PZTs with any phase difference (0−2π) based on single inductor. In addition, the circuit can harvest thermoelectric energy at an open-circuit voltage as low as 20 mV, and the maximum harvesting efficiency can be reached 85.7% at $V_{{\rm{oc}}}$ = 200 mV.