Abstract:For a low energy density piezoelectric transducer which powers wireless microsensors, it harvests little energy, and its output voltage is low. When the storage capacitor is charged by conventional management circuit, the energy transmission in low power leads to a high proportion of harvested energy dissipated in rectifying circuit, and little energy is transferred to the storage capacitor, which means low charging power. To overcome the large power dissipation and low charging power issues in low energy density environment, a novel management circuit is proposed, which involves quartz crystals with the high quality factor. The circuit uses quartz crystals to accumulate the harvested energy in little consumption. When the energy stored in the quartz crystal is high enough, it is released quickly, and then a higher input power is produced for the rectification circuit, which can reduce the proportion of energy dissipated in rectifying circuit. Hence, more energy is transferred to the storage capacitor, and a larger charging power can be obtained. Experiments show that for a piezoelectric transducer which harvests 50 Hz energy and produces 8 V voltage, the proposed circuit can improve the charging voltage and the charging power by 163% and 110% respectively, compared with the management circuit just using frequencyconversion matching technique.