| 摘要 |
The apparatus includes an ultrasonic transducer having a hand piece, an ultrasonic vibrating element secured to the hand piece and a probe coupled with the hand piece for propagating the ultrasonic oscillation produced by the ultrasonic vibrating element, a driving circuit for producing a driving signal for the ultrasonic vibrating element, a voltage controlled amplifier for amplifying the driving signal, an impedance matching transformer having a plurality of primary windings connected to the output of the voltage controlled amplifier via a switching circuit and a secondary winding connected to the ultrasonic vibrating element, a probe identification circuit for detecting the probe connected to the hand piece to produce a probe identification signal, a feedback control loop for generating a control voltage which is applied to the voltage controlled amplifier for controlling the amplification factor thereof in accordance with a driving current of the driving signal, an impedance detecting circuit for detecting the impedance of the ultrasonic transducer and controlling, the switching circuit such that a given primary winding is connected to attain the impedance matching between the driving circuit and the ultrasonic transducer, and a voltage limiter arranged in the feedback control loop such that the maximum value of the control voltage is limited in accordance with the probe identification signal.
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