| 摘要 |
PURPOSE:To improve power efficiency by a method wherein the voltage of a DC power source is subjected to step-up and step-down in respect to a control signal, a piezoelectric element is driven by a DC-DC converter which transfers electric power in birateral direction, and electric charge stored in the piezoelectric element is regenerated in the power source. CONSTITUTION:When a signal V1 is applied to the base of a transistor Tr31, it turns on and, from a DC power source 1, a current flows through a coil 50, in which magnetic energy is stored. When the Tr31 turns off, the energy stored in the coil 50 is supplied to the piezoelectric element 2 via a diode 41, and charges up the piezoelectric element 2, which generates displacement. After that, when Tr32 is made to turn on, the stored charge is supplied to the coil 50, in which magnetic energy is stored. When the Tr32 is made to turn off, the energy stored in the coil 50 flows into the DC power source 1 via a diode 42, and the power is regenerated.
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