Self-powered ultra-low-power low-threshold synchronous circuit for weak piezoelectric energy harvesting

Abstract

Existing piezoelectric energy harvesting circuits consume significant amount of power and have high input power threshold, creating challenges when the ambient input power is limited. This paper proposes a self-powered, ultra-low power control circuit for weak input power and heavy loads, operating intermittently at an extremely low duty cycle while only consuming 0.3 μW. By drawing power from the piezoelectric transducer at the maximum power point, the proposed circuit can operate efficiently when cold-starting at an input power threshold of 2 μW, ideal for harvesting natural vibrational energy which are often interrupted. When using a large 1 F storage capacitor and the DR-DSSH circuit, the proposed circuit can significantly outperform other synchronous circuits, achieving 21.3 % and 897.7 % better than DSSH and SEH, respectively, in terms of final charging voltage. The proposed circuit and control strategy can be applied to similar weak piezoelectric transducers for harvesting ambient energy.