Phacoemulsification device and method for using dual loop frequency and power control

Abstract

The invention is an improved phacoemulsification probe drive circuit for supplying electrical power to an ultrasonic transducer. The drive circuit has a power control loop and a frequency control loop. The power control loop has a variable gain amplifier whose output is an input to a power amplifier. After the power amplifier amplifies power, power is delivered to a transformer and, thereafter, to a transducer. The voltage and current applied to the primary of the transformer are sensed to generate a signal proportional to the power (real or apparent) and the result is compared against a power command originating from a foot pedal. Once compared, the result of this comparison is sent to a first controller which acts upon the information by sending a corrective signal to the variable gain amplifier. Also, the phase of the voltage and current waveforms applied to the primary of the transformer are sensed by a phase detector. The phase angle is then derived and compared against a phase command which is determined from the initial calibration of the system. The summer/difference block sends its resulting comparison to a second controller which sends a control signal to the voltage controlled oscillator (VCO). The VCO receives the signal and sends a specific frequency at a fixed voltage to the variable gain amplifier.

Dependencies are inferred from the claim text.