ULTRASOUND WAVE GENERATING APPARATUS

• US 20110285244A1
• Filed: 07/10/2009
• Published: 11/24/2011
• Est. Priority Date: 07/10/2008
• Status: Active Grant

• Current Assignee: Cornell University
• Original Assignee: Cornell University
• Inventors: Olbricht, William, Lewis, George K.
• Granted Patent: US 9,024,507 B2
• Time in Patent Office: Days
• US Class Current: 310/317
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: B06B 1/023 and stepped in amplitude, e.g. square wave, 2-level signal

Abstract

In one embodiment, there is provided in an ultrasound wave generating apparatus a low output impedance transistor based driver circuit that has the ability to apply a drive signal at a frequency corresponding to an ultrasound transducer'"'"'s resonant frequency. The low output impedance of the driver circuit allows for a substantial portion of the energy to be delivered to the ultrasound transducer and converted to ultrasound energy. The power transfer efficiency of the presented circuit allows ultrasound drivers to be powered by portable battery packs, while still delivering high ultrasound acoustic power. The ultrasound driver can provide energy in sufficient amounts making it suitable for a range of ultrasound driving applications including but not limited to therapeutic low and high power clinical systems, high intensity focused ultrasound HIFU, acoustical welding, industrial inspection, and other various forms of low-to-high power acoustic devices. Other embodiments of ultrasound transducer drivers and of other components of portable ultrasound generator apparatus in various embodiments are set forth herein.

Claims

1. An ultrasound wave generating apparatus comprising:

a power supply having a power source, a timing circuit, and a transistor based driver circuit for output of a drive signal, wherein the driver circuit includes a transistor pair including first and second transistors, and first and second clamping voltage terminals, the first and second transistors having respective first and second gates, wherein the timing circuit is operative to output a timing signal for controlling timing of the drive signal output by the driver circuit;

an ultrasound transducer configured to emit ultrasound energy, the ultrasound transducer being coupled to the driver circuit so that the drive signal output by the driver circuit drives the ultrasound transducer, wherein a frequency at which the ultrasound transducer emits maximum power when driven by the output drive signal defines a resonant frequency of the ultrasound transducer;

wherein the driver circuit is operative to output a drive signal having a frequency corresponding to the resonant frequency; and

wherein the apparatus is configured so that the transducer has an associated load voltage when the driver circuit outputs the drive signal to drive the transducer at a frequency corresponding to the resonant frequency, wherein the apparatus is further configured so that the driver circuit has an associated source voltage when the driver circuit outputs the drive signal at a frequency corresponding to the resonant frequency, and wherein the apparatus is configured so that the amplitude of the load voltage is at least 90 percent of the amplitude of the source voltage when the driver circuit outputs a drive signal at a frequency corresponding to the resonant frequency.

2. The ultrasound wave generating apparatus of claim 1, wherein the ultrasound transducer is operative so that compression force is imparted to the ultrasound transducer when the drive signal is of a first voltage polarity, and further so that an expansion force is imparted to the ultrasound transducer when the drive signal is of a second voltage polarity, and further so that the drive signal is a continuous bipolar drive signal so that both of compression forces and expansion forces are imparted to the ultrasound transducer.

3. The ultrasound wave generating apparatus of claim 1, wherein the ultrasound transducer is operative so that compression force is imparted to the ultrasound transducer when the drive signal is of a first voltage polarity, and further so that an expansion force is imparted to the ultrasound transducer when the drive signal is of a second voltage polarity, and further so that the drive signal is an imbalanced continuous bipolar drive signal so that both of compression forces and expansion forces are imparted to the ultrasound transducer, and further so that the compression forces are of greater magnitude than the expansion forces.

4. The ultrasound wave generating apparatus, of claim 1, wherein the driver circuit is operative so that the drive signal has an output current capacity of greater than 50 amperes.

5. The ultrasound wave generating apparatus of claim 1, wherein the power supply includes a capacitive coupling circuit coupling the timing signal to the first and second gates of the transistor pair, wherein the timing signal is a unipolar timing signal, and wherein the capacitive coupling circuit converts the unipolar timing signal into a bipolar input signal for input into the driver circuit.

6. The ultrasound wave generating apparatus of claim 1, wherein the transistor based driver circuit includes a plurality of transistor pairs connected in parallel, each of the transistor pairs having first and second transistors, wherein each of the transistor pairs is coupled to the first and second clamping voltage terminals.

7. The ultrasound wave generating apparatus of claim 1, wherein the ultrasound wave generating apparatus includes a user interface and is operative so that at least one characteristic of the drive signal can be changed in response to an operator control input that is input utilizing the user interface.

8. The ultrasound wave generating apparatus of claim 1, wherein the ultrasound wave generating apparatus is adapted so that the ultrasound transducer is incorporated in a replaceable ultrasound transducer assembly that is one of a plurality of candidate ultrasound transducer assemblies that can be associated to the ultrasound wave generating apparatus, and wherein the ultrasound wave generating apparatus is operative so that the drive signal has at least one characteristic that is responsive to which of the plurality of candidate ultrasound transducer assemblies is presently associated to the ultrasound wave generating apparatus.

9. The ultrasound wave generating apparatus of claim 1, wherein the ultrasound wave generating apparatus includes a user interface and is adapted so that the ultrasound transducer is incorporated in a replaceable ultrasound transducer assembly that is one of a plurality of candidate ultrasound transducer assemblies that can be associated to the ultrasound wave generating apparatus, wherein the ultrasound wave generating apparatus is operative so that the drive signal output by the driver circuit is responsive to each of (a) a switching of a candidate transducer assembly, and (b) a control input that is input by an operator utilizing the user interface.

10. The ultrasound wave generating apparatus of claim 9, wherein each of the plurality of candidate transducer assemblies includes a timing device disposed therein for controlling a timing of the driver circuit.

11. The ultrasound wave generating apparatus of claim 1, wherein the ultrasound wave generating apparatus is operative in a first mode of operation and in a second mode of operation, wherein the ultrasound wave generating apparatus in the first mode of operation outputs an imbalanced bipolar output drive signal, wherein the apparatus in the second mode of operation outputs an output drive signal that is selected from the group consisting of a unipolar output drive signal and a balanced output drive signal.

12. The ultrasound wave generating apparatus of claim 11, wherein the ultrasound wave generating apparatus includes a replaceable transducer assembly incorporating the transducer, the transducer assembly being one of a plurality of candidate transducer assemblies, wherein the ultrasound wave generating apparatus is operative so that the ultrasound wave generating apparatus switches operation from the first mode of operation to the second mode of operation responsively to the transducer assembly being replaced with another of the plurality of candidate transducer assemblies.

13. The ultrasound wave generating apparatus of claim 1, wherein the apparatus further includes a housing for housing the ultrasound transducer, the housing having a distal end at which the ultrasound transducer is disposed, wherein there is further disposed at the distal end a standoff component defining a cavity for carrying ultrasound coupling medium, the standoff component having a light transmissive wall adapted to permit visual viewing of an interior of the cavity through the light transmissive wall.

14. The ultrasound wave generating apparatus of claim 1, wherein the apparatus includes a transmission line coupling the driver circuit and the transducer, the transmission line including a plurality of coaxial cables arranged in parallel, and further being arranged in a braid configuration.

15. The ultrasound wave generating apparatus of claim 1, wherein the apparatus includes a transmission line coupling the driver circuit and the transducer, the transmission line including a plurality of coaxial cables arranged in parallel, and further being arranged in a twisted configuration.

16. The ultrasound wave generating apparatus of claim 1, wherein the transducer comprises a single transducer element having a first associated nominal frequency of resonance.

17. The ultrasound wave generating apparatus of claim 1, wherein the transducer comprises a plurality of transducer elements.

18. The ultrasound wave generating apparatus of claim 1, wherein the transducer comprises first and second transducer elements, the first transducer element having a first resonant frequency, the second transducer element having a second resonant frequency.

19. The ultrasound wave generating apparatus of claim 1, wherein the ultrasound transducer comprises first and second transducer elements, the first transducer element having a first resonant frequency, the second transducer element having a second resonant frequency, and wherein the apparatus is configured so that the driver circuit is operative to output a frequency sweeping drive signal, the frequency sweeping drive signal having a frequency corresponding to the first resonant frequency during a first period, the frequency sweeping drive signal having a frequency corresponding to the second resonant frequency during a second period.

20. The ultrasound wave generating apparatus of claim 1, wherein the power supply has a plurality of power supply stages, each power supply stage having an associated driver circuit and power source, wherein the plurality of the power supply stages include first and second power supply stages, the second power supply stage being successive in relation to the first power supply stage, and wherein an output of the first of the power supply stages is input into a stage ground of the second power supply stage.

21. The ultrasound wave generating apparatus of claim 1, wherein the power supply includes a user interface configured to permit an operator to independently adjust the first terminal clamping voltage and the second terminal clamping voltage via input of control inputs utilizing the user interface.

22. The ultrasound wave generating apparatus of claim 1, wherein the power source includes a battery power source.

23. The ultrasound wave generating apparatus of claim 1, wherein the power source includes an AC/DC converter.

24. The ultrasound wave generating apparatus of claim 1, wherein the driver circuit includes a MOSFET integrated circuit, and wherein the apparatus includes a housing and printed circuit board for carrying the MOSFET integrated circuit, the printed circuit having a peripheral edge that is proximate the housing when the printed circuit board is disposed in the housing, wherein the MOSFET integrated circuit is disposed on the printed circuit at a location that is more proximate the peripheral edge of the circuit board that a longitudinal centerline of the printed circuit board.

25. The ultrasound wave generating apparatus of claim 1, wherein the driver circuit includes a plurality of transistor pairs and a plurality of pin drivers for providing switching of the plurality of transistor pairs, wherein the driver circuit is configured so that each of the plurality of pin drivers for providing switching drives a common number of transistor pairs.

26. The ultrasound wave generating apparatus of claim 1, wherein the apparatus includes a printed circuit board carrying the first and second transistors of the driver circuit and wherein an output of the driver circuit includes common node that combines outputs of the first and second transistors, wherein the common output node is constituted by an output voltage plane having a planar surface area partially defining a surface of the printed circuit board.

27. An ultrasound wave generating apparatus comprising:

a power supply having a power source, a timing circuit, and a transistor based driver circuit for output of a drive signal, wherein the driver circuit includes a transistor pair including first and second transistors, and first and second clamping voltage terminals, the first and second transistors having respective first and second gates, wherein the timing circuit is operative to output a timing signal for controlling timing of the drive signal output by the driver circuit;

a hand held housing for housing the power supply;

an ultrasound transducer configured to emit ultrasound energy, the ultrasound transducer being coupled to the driver circuit so that the drive signal output by the driver circuit drives the ultrasound transducer, wherein a frequency at which the ultrasound transducer emits maximum power when driven by the output drive signal defines a resonant frequency of the ultrasound transducer;

wherein the driver circuit is operative to output a drive signal having a frequency corresponding to the resonant frequency; and

wherein the apparatus is configured so that the transducer has an associated load voltage when the driver circuit outputs the drive signal to drive the transducer at a frequency corresponding to the resonant frequency, wherein the apparatus is further configured so that driver circuit has an associated source voltage when the driver circuit outputs the drive signal at a frequency corresponding to the resonant frequency, and wherein the apparatus is configured so that the amplitude of the load voltage is at least 90 percent of the amplitude of the source voltage when the driver circuit outputs a drive signal at a frequency corresponding to the resonant frequency;

wherein the ultrasound transducer is operative so that compression force is imparted to the ultrasound transducer when the drive signal is of a first voltage polarity, and further so that an expansion force is imparted to the ultrasound transducer when the drive signal is of a second voltage polarity, and further so that the drive signal is an imbalanced continuous bipolar drive signal so that both of compression forces and expansion forces are imparted to the ultrasound transducer, and further so that the compression forces are of greater magnitude than the expansion forces;

wherein the driver circuit is operative so that the drive signal has an output current capacity of greater than 50 amperes.

wherein the power supply includes a capacitive coupling circuit coupling the timing signal to the first and second gates of the transistor pair, wherein the timing signal is a unipolar timing signal, and wherein the capacitive coupling circuit converts the unipolar timing signal into a bipolar input signal for input into the driver circuit;

wherein the transistor based driver circuit includes a plurality of transistor pairs connected in parallel, each of the transistor pairs having first and second transistors, wherein each of the transistor pairs is coupled to the first and second clamping voltage terminals;

wherein the ultrasound wave generating apparatus includes a user interface and is adapted so that the ultrasound transducer is incorporated in a replaceable ultrasound transducer assembly that is one of a plurality of candidate ultrasound transducer assemblies that can be associated to the ultrasound wave generating apparatus, wherein the ultrasound wave generating apparatus is operative so that the drive signal output by the driver circuit is responsive to each of (a) a switching of a candidate transducer assembly, and (b) a control input that is input by an operator utilizing the user interface;

wherein the apparatus further includes a housing for housing the ultrasound transducer, the housing having a distal end at which the ultrasound transducer is disposed, wherein there is further disposed at the distal end a standoff component defining a cavity for carrying ultrasound coupling medium, the standoff component having a light transmissive wall adapted to permit visual viewing of an interior of the cavity through the light transmissive wall;

wherein the apparatus includes a transmission line coupling the driver circuit and the transducer, the transmission line including a plurality of coaxial cables arranged in parallel, and further being arranged in one of a braid or twisted configuration;

wherein the power supply has a plurality of power supply stages, each power supply stage having an associated driver circuit and power source, wherein the plurality of the power supply stages include first and second power supply stages, the second power supply stage being successive in relation to the first power supply stage, and wherein an output of the first of the power supply stages is input into a stage ground of the second power supply stage.

wherein the user interface is configured to permit an operator to independently adjust the first terminal clamping voltage and the second terminal clamping voltage via input of control inputs utilizing the user interface;

wherein the power source includes a battery power source;

wherein the driver circuit includes a MOSFET integrated circuit, and wherein the apparatus includes a housing and printed circuit board for carrying the MOSFET integrated circuit, the printed circuit having a peripheral edge that is proximate the housing when the printed circuit board is disposed in the housing, wherein the MOSFET integrated circuit is disposed on the printed circuit at a location that is more proximate the peripheral edge of the circuit board that a longitudinal centerline of the printed circuit board;

wherein the driver circuit includes a plurality of transistor pairs and a plurality of pin drivers for providing switching of the plurality of transistor pairs, wherein the driver circuit is configured so that each of the plurality of pin drivers for providing switching drives a common number of transistor pairs; and

wherein the apparatus includes a printed circuit board carrying the first and second transistors of the driver circuit and wherein an output of the driver circuit includes common node that combines outputs of the first and second transistors, wherein the common output node is constituted by an output voltage plane having a planar surface area partially defining a surface of the printed circuit board.

28. An ultrasound wave generating apparatus comprising:

a power supply having a timing circuit for outputting a timing signal, and a transistor based driver circuit for output of a drive signal, wherein the driver circuit includes a transistor pair including first and second transistors, and first and second clamping voltage terminals, the first and second transistors having respective first and second gates, wherein the timing circuit is operative to output a timing signal for controlling timing of the drive signal output by the driver circuit;

an ultrasound transducer configured to emit ultrasound energy, the ultrasound transducer being coupled to the driver circuit so that the drive signal output by the driver circuit drives the ultrasound transducer, wherein the ultrasound transducer includes an impedance rating and a frequency rating and wherein the driver circuit is operative to output the drive signal at a frequency of about the frequency rating of the ultrasound transducer; and

wherein the driver circuit includes an output impedance and wherein the apparatus is configured so a value of the output impedance of the driver circuit is less than 10 percent of a value of the impedance rating of the ultrasound transducer.

29. The ultrasound wave generating apparatus of claim 28, wherein the ultrasound wave generating apparatus is operative to output more than 50 Watts of ultrasound energy.

30. The ultrasound wave generating apparatus of claim 28, wherein the power supply includes a capacitive coupling circuit coupling the timing signal to the first and second gates of the transistor pair, wherein the timing signal is a unipolar timing signal, and wherein the capacitive coupling circuit converts the unipolar timing signal into a bipolar input signal for input into the driver circuit.

31. The ultrasound wave generating apparatus of claim 28, wherein the transistor based driver circuit includes a plurality of transistor pairs connected in parallel, each of the transistor pairs having first and second transistors, wherein each of the transistor pairs is coupled to the first and second clamping voltage terminals.

32. The ultrasound wave generating apparatus of claim 28, wherein the apparatus includes a battery power source.

33. The ultrasound wave generating apparatus of claim 28, wherein the power supply includes a user interface configured to permit an operator to independently adjust the first terminal clamping voltage and the second terminal clamping voltage via input of control inputs utilizing the user interface.

34. An ultrasound wave generating apparatus comprising:

a power supply having a timing circuit for outputting a timing signal, and a transistor based driver circuit for output of a drive signal, wherein the driver circuit includes a transistor pair including first and second transistors, and first and second clamping voltage terminals, the first and second transistors having respective first and second gates, wherein the timing circuit is operative to output a timing signal for controlling timing of the drive signal output by the driver circuit;

an ultrasound transducer configured to emit ultrasound energy, the ultrasound transducer being coupled to the driver circuit so that the drive signal output by the driver circuit drives the ultrasound transducer, wherein the ultrasound transducer includes an impedance rating and a frequency rating and wherein the driver circuit is operative to output the drive signal at a frequency of about the frequency rating of the ultrasound transducer;

wherein the driver circuit includes an output impedance and wherein the apparatus is configured so a value of the output impedance of the driver circuit is less than 10 percent of a value of the impedance rating of the ultrasound transducer;

wherein the ultrasound wave generating apparatus is operative to output more than 50 Watts of ultrasound energy;

wherein the power supply includes a capacitive coupling circuit coupling the timing signal to the first and second gates of the transistor pair, wherein the timing signal is a unipolar timing signal, and wherein the capacitive coupling circuit converts the unipolar timing signal into a bipolar input signal for input into the driver circuit;

wherein the transistor based driver circuit includes a plurality of transistor pairs connected in parallel, each of the transistor pairs having first and second transistors, wherein each of the transistor pairs is coupled to the first and second clamping voltage terminals;

wherein the apparatus includes a battery power source; and

wherein the power supply includes a user interface configured to permit an operator to independently adjust the first terminal clamping voltage and the second terminal clamping voltage via input of control inputs utilizing the user interface.