Note: Weak acoustic energy harvesting and high-efficiency storage-energy management circuit for wireless sensor

A Helmholtz resonator can harvest the weak acoustic energy, but the traditional management circuits hardly efficiently obtain the weak energy due to the diode drop of the rectifier. A high-efficiency management circuit for the weak energy is developed, and the conjugate impedance matching of the piezoelectric transducer and the energy storage of the inductance are realized. The proposed circuit has 59% and 94% higher charging voltages than traditional double synchronized switch harvesting and series synchronized switching harvesting with inductor circuits. The Helmholtz resonator with the proposed circuit can drive wireless sensors at a weak acoustic pressure of 0.2 Pa and can be used in other weak energy harvesters.