| 摘要 |
PURPOSE:To reduce in size and cost by providing a control circuit for oscillating a drive signal and a brake signal as a pulse train in which a ratio of application times of high to low level voltage is differentiated in an aging manner. CONSTITUTION:Assume that a brake signal has a low level voltage and a switch circuit 5 is interrupted. When a drive signal has a high level voltage, a switch circuit 4 is conducted, and with an exciting voltage V as an electromotive force a series closed circuit of a coil 3 and a piezoelectric actuator 1 is formed. When the drive signal has a low level voltage, the circuit 4 is interrupted. In this case, electromagnetic energy stored in the coil 3 is moved to the actuator 1 when the high level voltage of the drive signal is applied, and the terminal voltage Va of the actuator 1 is raised that much. That is, since the terminal voltage is raised in one step of conducting and interrupting the circuit 4, the terminal voltage can be additionally raised by repeating the step. The rising gradient and shape of the voltage Va can be variably controlled by a pulse train in which the ratio of application times of high to low level voltage is differentiated in an aging manner. |
