System and method for generating radio frequency energy

• US 20070225698A1
• Filed: 03/21/2006
• Published: 09/27/2007
• Est. Priority Date: 03/21/2006
• Status: Active Grant

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Sherwood Services AG
• Inventors: McPherson, James, Orszulak, James
• Granted Patent: US 7,648,499 B2
• Time in Patent Office: Days
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor

Abstract

An electrosurgical generator is disclosed. The electrosurgical generator includes a power supply for generating a DC voltage. The electrosurgical generator also includes a first parallel inductor-capacitor circuit being driven by a first signal at a first predetermined frequency and a second parallel inductor-capacitor inductor-capacitor circuit driven by a second signal at the first predetermined frequency phase shifted 180°. The electrosurgical generator further includes a series inductor-capacitor resonant circuit operably connected in series with a primary winding of a transformer. The first and second parallel inductor-capacitor circuits are operably connected to the transformer, such that the first inductor-capacitor circuit generates a positive half sine wave and the second inductor-capacitor circuit generates a 180° phase-shifted positive half sine wave to generate a full sine wave in a secondary winding of the transformer.

Claims

1. An electrosurgical generator comprising:

a power supply operable to generate a DC voltage;

a first parallel inductor-capacitor circuit configured to be driven by a first signal at a first predetermined frequency;

a second parallel inductor-capacitor circuit configured to be driven by a second signal at the first predetermined frequency phase-shifted 180°

; and

a series inductor-capacitor resonant circuit operably connected in series with a primary winding of a transformer, the first and second parallel inductor-capacitor circuits operably connected to the transformer, the first parallel inductor-capacitor circuit being configured to generate a positive half sine wave from the DC voltage and the second parallel inductor-capacitor circuit being configured to generate a 180°

phase-shifted positive half sine wave from the DC voltage to generate a full sine wave in a secondary winding of the transformer.

2. An electrosurgical generator as in claim 1, wherein the first parallel inductor-capacitor resonant circuit is tuned to a first self-resonant frequency that is substantially equivalent to the first predetermined frequency.

3. An electrosurgical generator as in claim 2, wherein the first parallel inductor-capacitor resonant circuit includes a first inductor having a first inductance value and a first capacitor having a first capacitance value, wherein the first inductance value and the first capacitance correspond to the first self-resonant frequency.

4. An electrosurgical generator as in claim 1, wherein the second parallel inductor-capacitor resonant circuit is tuned to a second self-resonant frequency that is substantially equivalent to the first predetermined frequency.

5. An electrosurgical generator as in claim 4, wherein the second parallel inductor-capacitor resonant circuit includes a second inductor having a second inductance value and a second capacitor having a second capacitance value, wherein the second inductance value and the second capacitance correspond to the second self-resonant frequency.

6. An electrosurgical generator as in claim 1, wherein the first and second parallel inductor-capacitor circuit are driven by switching on and off first and second switching components respectively.

7. An electrosurgical generator as in claim 6, wherein the first and second switching components are selected from the group consisting of transistors, relays, metal-oxide semiconductor field-effect transistors and insulated gate bipolar transistors.

8. An electrosurgical generator as in claim 1, wherein the series inductor-capacitor resonant circuit is tuned to a third self-resonant frequency that is substantially equivalent to the predetermined frequency.

9. An electrosurgical generator as in claim 8, wherein the series inductor-capacitor resonant circuit includes a third inductor having a third inductance value and a third capacitor having a third capacitance value, wherein the third inductance value and the third capacitance correspond to the third self-resonant frequency.

10. A method for generating high frequency electrosurgical current comprising the steps of:

providing a power supply operable to generate a DC voltage, a first parallel inductor-capacitor circuit, a second parallel inductor-capacitor circuit, a series inductor-capacitor resonant circuit, wherein the first parallel inductor-capacitor circuit, the second parallel inductor-capacitor circuit, and the series inductor-capacitor resonant circuit are operably connected in series with a primary winding of a transformer;

driving the first parallel inductor-capacitor circuit by a first signal at a first predetermined frequency;

driving the second parallel inductor-capacitor inductor-capacitor circuit by a second signal at the first predetermined frequency phase-shifted 180°

; and

generating a positive half sine wave at the first inductor-capacitor parallel circuit;

generating a 180°

phase-shifted positive half sine wave at the second parallel inductor-capacitor circuit; and

combining the positive half sine wave and the 180°

phase-shifted positive half sine wave at a secondary winding of the transformer to generate a full sine wave.

11. A method as in claim 10, wherein the first parallel inductor-capacitor resonant circuit of the providing step is tuned to a first self-resonant frequency that is substantially equivalent to the first predetermined frequency.

12. A method as in claim 11, wherein the first parallel inductor-capacitor resonant circuit of the providing step includes a first inductor having a first inductance value and a first capacitor having a first capacitance value, wherein the first inductance value and the first capacitance correspond to the first self-resonant frequency.

13. A method as in claim 10, wherein the second parallel inductor-capacitor resonant circuit of the providing step is tuned to a second self-resonant frequency that is substantially equivalent to the first predetermined frequency.

14. A method as in claim 13, wherein the second parallel inductor-capacitor resonant circuit includes a second inductor having a second inductance value and a second capacitor having a second capacitance value, wherein the second inductance value and the second capacitance correspond to the second self-resonant frequency.

15. A method as in claim 10, wherein the first and second parallel inductor-capacitor circuits of the providing step are each driven in the respective driving steps by switching on and off first and second switching components respectively.

16. A method as in claim 15, wherein the first and second switching components are selected from the group consisting of transistors, relays, metal-oxide semiconductor field-effect transistors and insulated gate bipolar transistors.

17. A method as in claim 10, wherein the series inductor-capacitor resonant circuit of the providing step is tuned to a third self-resonant frequency that is substantially equivalent to the predetermined frequency.

18. A method as in claim 17, wherein the series inductor-capacitor resonant circuit of the providing step includes a third inductor having a third inductance value and a third capacitor having a third capacitance value, wherein the third inductance value and the third capacitance correspond to the third self-resonant frequency.

19. A radio frequency output stage circuit, comprising:

a first parallel inductor-capacitor circuit configured to generate a positive half sine wave driven by a first signal at a first predetermined frequency, the first parallel inductor-capacitor circuit being operably connected to a transformer which includes a first winding and a series inductor-capacitor resonant circuit connected in series to a second winding;

a second parallel inductor-capacitor circuit configured to generate a 180°

phase-shifted positive half sine wave driven by a second signal at the first predetermined frequency phase-shifted 180°

, the second parallel inductor-capacitor circuit being operably connected to the transformer such that the positive half sine wave and the 180°

phase-shifted positive half sine wave are combined at the secondary winding of the transformer to generate a full sine wave.