| 摘要 |
PURPOSE: To make it possible to perform charging and discharging operations by making electrical insulation unnecessary for a signal transmitting system and thus applying a high voltage to a capacitive load. CONSTITUTION: A high-voltage (200V) charging power supply 24 is so connected as to be grounded through an emitter-collector of a pnp type charging transistor 23 and a collector-emitter of an npn type discharging transistor 27; and a piezoelectric actuator 21 as a capacitive load and a current detecting resistor 26 are connected in series to a common collector. For the base drive of transistors 32 and 27, an npn type transistor 29 for charging control and a pnp type transistor 32 for discharging control are respectively connected with the emitters in common, and a 5-V control power supply 31 is connected to the emitter. When an output voltage of a differential amplifier circuit 33 comprising a linear IC is given to the bases of the transistors 29 and 32, a high voltage of the charging power supply 24 is applied to the piezoelectric actuator 21 for performing charging and discharging operations. |
