A Fully Integrated Sequential Synchronized Switch Harvesting on Capacitors Rectifier Based on Split- Electrode for Piezoelectric Energy Harvesting

Synchronized rectifiers offer promising solutions for piezoelectric energy harvesting; however, achieving the promised energy extraction performance necessitates using either a bulky inductor or multiple large capacitors, which cannot be on-chip integrated and increase the system form factor. This article introduces a fully integrated sequenced synchronized switch harvesting on capacitors (3SHC) rectifier. The input piezoelectric transducer (PT) uses microelectromechanical system technology. The cantilever is equally split into multiple strongly coupled subcantilevers, with each cantilever treated as an individual PT connected to the proposed rectifier. The 3SHC rectifier cyclically operates multiple times to synchronously flip the voltage of each cantilever sequentially. With the proposed design, all the flying capacitors only need to match the capacitance of each subcantilever; hence, they can be fully integrated on-chip. The design is fabricated using standard 0.18
$\mu \text{m}$
CMOS technology. Measurement results show that the proposed 3SHC rectifier attains an 80% voltage flip efficiency and achieves a 730% power enhancement compared to a full-bridge rectifier.