System and method for generating radio frequency energy
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.
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°;
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;
and
a temperature circuit configured to determine temperature at a surgical site and adjust the DC voltage generated by the power supply.
2. An electro surgical 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. An electrosurgical generator as in claim 1 , wherein temperature is sensed proximate the surgical site by a temperature sensor disposed on a remote electrode.
11. 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, the series inductor-capacitor resonant circuit are operably connected in series with a primary winding of a transformer, and a temperature circuit configured to determine temperature at a surgical site and adjust the DC voltage generated by the power supply;
driving the first parallel inductor-capacitor circuit by a first signal at a first predetermined frequency;
driving the second parallel 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;
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; and
determining temperature at the surgical site by the temperature circuit to adjust the DC voltage generated by the power supply.
12. A method as in claim 11 , 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.
13. A method as in claim 12 , 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.
14. A method as in claim 11 , 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.
15. A method as in claim 14 , 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.
16. A method as in claim 11 , 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.
17. A method as in claim 16 , 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.
18. A method as in claim 11 , 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.
19. A method as in claim 18 , 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.
20. A method as in claim 11 , wherein the temperature circuit of the determining step senses temperature proximate the surgical site by a temperature sensor disposed on a remote electrode.