Switched resonant ultrasonic power amplifier system

• US 7,396,336 B2
• Filed: 10/27/2004
• Issued: 07/08/2008
• Est. Priority Date: 10/30/2003
• Status: Active Grant

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Sherwood Services AG
• Inventors: Orszulak, James H., McPherson, James W.
• Primary Examiner(s): Gibson; Roy D.
• Assistant Examiner(s): VRETTAKOS, PETER J
• Application Number:
  US10/974,332
• Publication Number:
  US 20050149151A1
• Time in Patent Office: 1,350 Days
• Field of Search: 607/96, 606 27- 52, 601/2, 310311- 16
• US Class Current: 601/2
• CPC Class Codes: A61N 2007/0056 Beam shaping elements
• CPC Class Codes: A61N 7/00 Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092
• CPC Class Codes: B06B 1/0253 taken directly from the generator circuit
• CPC Class Codes: B06B 1/0261 taken from a transducer or electrode connected to the driving transducer
• CPC Class Codes: B06B 2201/76 Medical, dental
• CPC Class Codes: H10N 30/802 Drive or control circuitry or methods for piezoelectric or electrostrictive devices not otherwise provided for

Abstract

A switched resonant power amplifier system for ultrasonic transducers is disclosed. The system includes an amplifier that receives and processes a driver output signal for generating a drive signal that is provided to an ultrasonic device for controlling output of the ultrasonic device. An output control circuit receives and processes a signal related to a feedback signal generated by the ultrasonic device and a divider reference signal, and generates a compensated clock signal that is adjusted for at least one of phase and frequency differences between the received feedback signal and the divider reference signal. A compensated drive circuit receives and processes the compensated clock signal for generating the divider reference signal, and for generating the driver output signal.

Claims

1. A system for controlling an output of a surgical ultrasonic device, the system comprising:

a switched resonant power amplifier receiving and processing a driver output signal for generating a drive signal that is provided to an ultrasonic device for controlling the output of the ultrasonic device;

an output control circuit comprising;

a wave shaping circuit comprising;

a zero crossing detector receiving and processing a feedback signal related to the output of the ultrasonic device and generated by the ultrasonic device, the zero crossing detector generating a corresponding square wave signal; and

a comparator comparing the square wave signal to a reference signal for generating a reset signal having a substantially identical frequency to the feedback signal;

a compensating circuit comprising;

a reference timer for receiving and processing the reset signal for generating a compensated reference signal having substantially the same frequency as the reset signal and substantially 180°

out-of-phase with respect to the reset signal, wherein frequency and amplitude characteristics of the compensated reference signal are determined at least by the reset signal; and

a phase locked loop (PLL) receiving first and second input signals, wherein the first input signal is the compensated reference signal and the second input signal is a divider reference signal, and wherein the PLL processes the first and second input signals for generating a compensated clock signal that is adjusted for at least one of phase and frequency differences between the received first and second input signals; and

a compensated drive circuit operatively coupled to the compensating circuit, the compensated drive circuit comprising;

divider circuitry for stepping down the frequency of the compensated clock signal to a selectable frequency for generating a counter output signal;

flip-flop circuitry for splitting the counter output signal into first and second complementary square waves together forming a driver input signal, wherein a sample of at least one of the first and second complementary square waves is the divider reference signal; and

a driver for amplifying the driver input signal for generating the driver output signal.

2. The system of claim 1, wherein the feedback signal is indicative of the output of the ultrasonic device, and the output of the ultrasonic device is controlled in real time.

3. The system of claim 2, wherein the switched resonant power amplifier includes a transformer having primary and secondary windings, wherein the drive signal is coupled to the secondary winding of the transformer.

4. The system of claim 2, wherein the switched resonant power amplifier includes at least one tuning circuit having a tuned period selected to correspond to a particular resonant frequency of the driver output signal.

5. The system of claim 2, wherein the amplifier includes first and second switching elements receiving the driver output signal, and the first and second complementary signals of the driver output signal are coupled to the first and second switching elements, respectively.

6. The system of claim 2, wherein the driver includes a phase delay circuit for selectively adjusting at least one of the phase relationship between the first and second complementary signals of the driver output signal and pulse width of pulses of at least one of the first and second complementary signals of the driver output signal.

7. The system of claim 6, wherein the adjusting by the phase delay circuit provides for controlling the output of the ultrasonic device for producing a pulsed output from the ultrasonic device.