Ultrasonic surgical device

An ultrasonic surgical device having an ultrasonic oscillation circuit and an ultrasonic transducer with an electrostriction type vibrator, said oscillation circuit comprising:

• power supply means including a rectifier circuit means for converting AC current from an AC power source into DC current,
• means for connecting said AC power source and said rectifier circuit means to reduce rush current from said AC power source to said rectifier circuit means;
• a smoothing circuit means connected to said rectifier circuit means for reducing ripples of the DC current;
• a power amplifier circuit means connected to said smoothing circuit means to produce an amplified electric signal,
• means connected to said amplifier circuits means for suppressing spike wave of the amplified electric signal,
• matching-circuit means connected to said spike-suppressing means for supplying an electric signal of a reduced loss to said ultrasonic transducer in response to load increase thereof,
• means connected to said matching-circuit means for setting an amplitude level of the supplied electric signal to stably operate said transducer with a low loss,
• means for connecting said amplitude-level setting means and said transducer to drive said transducer and produce a feedback signal,
• means for feeding back the feedback signal to said power amplifier circuit means, said feedback means including quality-factor adjusting means and feedback signal filtering means for filtering out spurious frequency signals,
• means connected to said power amplifier circuit means to adjust the amplitude of said amplified electric signal, and
• starting-impulse reducing means connected between said smoothing circuit means and said power amplifier circuit means to reduce the impulse of the DC current to the latter at start of oscillation.