A zero bias highly efficient active diode circuit for piezoelectric energy harvester

Abstract

This paper presents a MOS based active diode circuit for efficient rectification of piezoelectric energy harvester (PZEH). The active diode consists of a PMOS switch along with auto tuned control circuit to control the gate of the PMOS. The strength of gate voltage of the PMOS in conducting state has been improved to provide the low forward resistance at high current. In the on-state, the voltage drop across the active diode is 33 mV at diode current of 136 µA. The maximum reverse leakage current in the non conduction state of PMOS has been reduced from 18 µA of conventional MOS diode to 1.5 µA. The auto tuned control circuit does not require external bias. The active rectifier using proposed active diode used for ac to dc conversion of PZEH output has been presented in this paper. The circuit provides a power conversion efficiency of 94% which is 36% better than the conventional MOS based rectifier.