| 摘要 |
PURPOSE:To oscillate and drive a piezoelectric element at the high speed of response while following up a voltage command by forming a discharge circuit to surplus charges charged to the piezoelectric element at an initial stage every time set voltage is changed over from high voltage to low voltage in a chopper circuit. CONSTITUTION:Voltage commands corresponding to two kinds of high and low set voltage are transmitted alternately over a comparison circuit 7 from a voltage-command changeover circuit 8 while being synchronized with a pulse oscillating signal output from an oscillation circuit 9, The switching-transistors Tr1 and Tr4 of a chopper circuit 3 are turned ON and a Tr2 and Tr3 OFF on the basis of the voltage commands. The voltage of a DC power 2 is applied to an element 1 at a positive mode. When charging is started at first set voltage V1 first in the element 1 at that time, a feedback signal corresponding to the terminal voltage of the piezoelectric element 1 and voltage V1 are compared by the circuit 7 in a charging process, and the switching-transistors Tr1, Tr4 of the chopper circuit 3 are chopping-controlled so that the terminal voltage of the element 1 is maintained at set voltage V1. |
