Method of actuating ultrasonic drive device, ultrasonic drive device, and ultrasonic treatment system

A method of actuating an ultrasonic drive device, the method comprising:

• sweeping, by a first control circuit, a frequency at which an ultrasonic transducer oscillates from a predetermined frequency toward a resonant frequency;
• predicting, by a prediction circuit, whether or not ringing occurs based on a first parameter representing a driving state of the ultrasonic transducer;
• and
• responsive to the prediction circuit predicting that ringing does not occur and when a second parameter representing a frequency at which the ultrasonic transducer is driven satisfies a predetermined condition, resonantly driving, by a second control circuit, the ultrasonic transducer at a resonant frequency by phase locked loop (PLL) control, wherein:
• when the prediction circuit predicts that the ringing occurs, the second control circuit adjusts a third parameter for controlling driving of the ultrasonic transducer to prevent the ringing from occurring, and wherein when the second parameter satisfies a predetermined condition, the second control circuit resonantly drives the ultrasonic transducer at a resonant frequency by PLL control:
• the predetermined condition is a set value that triggers a resonant drive phase during which the ultrasonic transducer is resonantly driven at the resonant frequency;
• and
• satisfying the predetermined condition corresponds to the second parameter being equal to or greater than the set value.