A cold-startup SSHC rectifier for piezoelectric energy harvesting

To solve the conversion efficiency of piezoelectric energy harvesting (PEH), this brief presents a cold-startup synchronous switch harvesting on capacitors (SSHC) technology, which based on the traditional full-bridge rectifier (FBR) and synchronous switch harvesting on inductor (SSHI). The circuit can provide a high open-circuit voltage in the cold state, and accelerates into a normal working state. The internal switched capacitors (SCs) replace the inductor to quickly flip the charge, reduces energy consumption, and achieves high flip efficiency. The design is fabricated using TSMC 0.18 μm CMOS process. The efficiency calculations show that the piezoelectric harvester is up to 5.5 X at 4.5 V open-circuit voltage compared to traditional full-bridge rectifier, surpassing most SSHI rectifier circuits and significantly reducing system area. The simulation results show that the voltage turnover efficiency of the designed four-capacitor SSHC rectifier is 66.36%.