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

• US 6,203,516 B1
• Filed: 08/21/1997
• Issued: 03/20/2001
• Est. Priority Date: 08/29/1996
• Status: Expired due to Term

• Current Assignee: Bausch & Lomb Incorporated (Bausch Health Cos., Inc.)
• Original Assignee: Bausch & Lomb Incorporated (Bausch Health Cos., Inc.)
• Inventors: Kepley, Kevin Paul
• Primary Examiner(s): Kennedy, Sharon
• Assistant Examiner(s): Hayes, Michael J.
• Application Number:
  US08/915,991
• Time in Patent Office: 1,307 Days
• Field of Search: 604/20, 604/22, 606/34, 606/38, 606/127, 606/128, 606/107, 601/2, 310/316.01, 310/317, 323/282, 323/285, 702/64, 702/71, 702/72
• US Class Current: 604/22
• CPC Class Codes: A61B 17/00 Surgical instruments, devices or methods, e.g. tourniquets A61B18/00 takes precedence; contraceptive devices, pessaries, or applicators therefor A61F6/00; eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 50/10 Furniture specially adapted for surgical or diagnostic appliances or instruments
• CPC Class Codes: A61B 90/36 Image-producing devices or illumination devices not otherwise provided for
• CPC Class Codes: A61F 9/00745 using mechanical vibrations, e.g. ultrasonic
• CPC Class Codes: A61M 2205/505 Touch-screens; Virtual keyboard or keypads; Virtual buttons; Soft keys; Mouse touches
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: H01H 2003/008 with a haptic or a tactile feedback controlled by electrical means, e.g. a motor or magnetofriction
• CPC Class Codes: H01H 2300/04 Programmable interface between a set of switches and a set of functions, e.g. for reconfiguration of a control panel

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.

Claims

1. A circuit for a phacoemulsification probe system comprising:

a frequency loop controller having an output connected to an input of a voltage controlled oscillator;

a power loop controller having an output connected to an input of a variable gain amplifier;

said voltage controlled oscillator having an output connected to an input of said variable gain amplifier;

a power amplifier connected to an output of said variable gain amplifier;

said power amplifier delivering power including voltage and current waveforms to an isolated power transformer;

a power monitor connected to and sensing said power delivered to said isolated power transformer;

a power summer having an input connected to an output of said power monitor, and having an output connected to said power loop controller;

a phase detector connected to and sensing said voltage and current waveforms delivered to said isolated power transformer; and

a phase summer having an input connected to an output of said phase detector, and having an output connected to said frequency loop controller.

2. A circuit for a phacoemulsification probe system according to claim 1, wherein said power monitor comprises:

a voltage RMS to DC converter connected to and sensing the voltage waveform delivered to said isolated power transformer;

a current RMS to DC converter connected to and sensing the current waveform delivered to said isolated power transformer;

a multiplier having one input connected to said voltage RMS to DC converter and another input connected to said current RMS to DC converter, and having an output connected to said power summer.

3. A circuit for a phacoemulsification probe system according to claim 1, wherein said power monitor comprises:

a multiplier having one input connected to and sensing the voltage waveform delivered to said isolated power transformer and another input connected to and sensing the current waveform delivered to said isolated power transformer; and

a low pass filter having an input connected to an output of said multiplier, and having an output connected to said phase summer.