Electrosurgical Apparatus With High Speed Energy Recovery

• US 20100063497A1
• Filed: 09/05/2008
• Published: 03/11/2010
• Est. Priority Date: 09/05/2008
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Tyco Healthcare Group LP (Medtronic Plc)
• Inventors: Orszulak, James H.
• Granted Patent: US 8,377,053 B2
• Time in Patent Office: Days
• US Class Current: 606/35
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/1445 at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod
• CPC Class Codes: A61B 2018/00345 Vascular system
• CPC Class Codes: A61B 2018/00404 Blood vessels other than those in or around the heart
• CPC Class Codes: A61B 2018/00619 Welding
• CPC Class Codes: A61B 2018/0063 Sealing
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00892 Voltage

Abstract

A circuit for controlling the discharging of stored energy in an electrosurgical generator includes a pulse modulator which controls an output of a power supply. At least one comparator is configured to provide an error signal to the pulse modulator based on a comparison between an output signal generated by the power supply and a feedback signal generated in response to the application of energy to tissue. A discharge circuit is configured to control the discharge of the output of the power supply to an inductive load disposed in parallel with the output of the power supply based on the comparison between the output signal and the feedback signal. The discharge circuit provides a rapid response and time rate control of the delivered electrosurgical energy by controlling the power supply and delivered RF energy in real time, based on a feedback signal generated in response to the application of energy to tissue.

Claims

1. A circuit for controlling the discharging of stored energy in an electrosurgical generator comprising:

a pulse modulator which controls an output of a power supply;

at least one comparator configured to provide an error signal to the pulse modulator based on a comparison between an output generated by the power supply and a feedback signal generated in response to the application of energy to tissue; and

a discharge circuit configured to control the discharge of the output of the power supply to an inductive load disposed in parallel therewith based on the comparison between the output generated by the power supply and the feedback signal.

2. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 1, wherein the error signal is generated based on the feedback signal being less than the output generated by the power supply.

3. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 1, wherein the discharge circuit includes a first switching component configured to discharge the output of the power supply to the inductive load and a second switching component configured to control switching of the first switching component based on the discharge of the output to the inductive load.

4. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 3, wherein the discharge circuit further includes a resistive element connected in series between the first switching component and ground.

5. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 4, wherein a switching of the second switching component is controlled by a voltage across the resistive element generated by the discharge of the output of the power supply.

6. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 3, wherein the discharge circuit includes at least one comparator configured to switch the first switching component based on the comparison between the output generated by the power supply and the feedback signal.

7. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 3, wherein at least one of the first and second switching components is a transistor.

8. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 7, wherein the transistor is selected from the group consisting of a field-effect transistor (FET), a metal-oxide semiconductor field-effect transistor (MOSFET), and an insulated gate bipolar transistor (IGBT).

9. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 1, wherein the discharge circuit further includes at least one diode configured to direct current from the inductive load.

10. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 1 further comprising a power supply output filter comprising an inductor and a capacitor.

11. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 1, wherein the at least one comparator is an operational amplifier.

12. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 1, wherein the pulse modulator is a pulse width modulator.

13. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 1, wherein the pulse modulator is a phase shift modulator.

14. A circuit for controlling the discharging of stored energy in an electrosurgical generator comprising:

a pulse modulator which controls an output of a power supply;

at least one comparator configured to provide an error signal to the pulse modulator based on a comparison between an output generated by the power supply and a feedback signal generated in response to the application of energy to tissue; and

a discharge circuit having a first switching component configured to discharge the output of the power supply to an inductive load disposed in parallel therewith if feedback signal is less than the output signal and a second switching component configured to control switching of the first switching component based on the discharge of the output to the inductive load.

15. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 14, further comprising a full bridge power stage controlled by the pulse modulator, the full bridge power stage configured to provide a direct current to the output of the power supply.

16. A circuit for controlling the discharging of stored energy in an electrosurgical generator according to claim 15, further comprising a power supply output filter comprising an inductor and a capacitor.

17. A method for controlling the discharging of stored energy in an electrosurgical generator comprising the steps of:

applying energy stored in an output of a power supply to tissue;

generating at least one control signal based on at least one of a sensed tissue property and a sensed power delivery property;

generating an error signal based on a comparison between the at least one control signal and the energy stored in the output; and

discharging the stored energy to an inductive load in parallel with the output of the power supply based upon the comparison between the energy stored in the output and the control signal.

18. A method according to claim 17, wherein the error signal of the generating step is based on the feedback signal being less than the output signal.

19. A method according to claim 17, wherein the driving step further comprises the steps of:

activating a first switching component to discharge the stored energy to the inductive load; and

activating a second switching component based on the discharge of the stored energy to control the activation of the first switching component.

20. A method according to claim 19, further comprising the steps of;

providing a resistive element connected in series between the first switching component and ground; and

controlling a second switching component based on a voltage across the resistive element generated by the discharge of stored energy to selectively activate the first switching component.

21. A method according to claim 17, further comprising the step of directing current from the inductive load to at least one diode.

22. A method according to claim 17, wherein the output of the power supply of the applying step includes an output filter comprising an inductor and a capacitor adapted to store energy.