RF Generator System for Surgical Vessel Sealing

• US 20120098351A1
• Filed: 10/20/2011
• Published: 04/26/2012
• Est. Priority Date: 10/22/2010
• Status: Active Grant

• Current Assignee: Bolder Surgical, LLC (Hologic Incorporated)
• Original Assignee: JustRight Surgical, LLC (Hologic Incorporated)
• Inventors: Ross, David
• Granted Patent: US 9,039,694 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: A61B 18/1233 with circuits for assuring patient safety
• CPC Class Codes: A61B 18/1442 Probes having pivoting end effectors, e.g. forceps
• CPC Class Codes: A61B 2018/0063 Sealing
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00779 Power or energy
• CPC Class Codes: A61B 2018/00827 Current
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00892 Voltage
• CPC Class Codes: H02M 7/48 using discharge tubes with control electrode or semiconductor devices with control electrode
• CPC Class Codes: H02M 7/539 with automatic control of output wave form or frequency H02M7/5375 - H02M7/5387 take precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Systems, methods, and apparatus for providing power to an electrosurgical instrument. In particular, a power supply is disclosed in which non-sinusoidal (e.g., pulsed) constant frequency voltage having a variable amplitude is passed to an LC circuit to produce a quasi-sinusoidal current in the LC circuit. The constant driving frequency can be one half the resonant frequency of the LC circuit allowing the LC circuit to operate as an impedance, and thus limit current spikes and arcing. The frequency and phasing of the driving voltage also enables the LC circuit to discharge energy back into a power provider of the power supply so that energy does not build up in the LC circuit. These features result in less severe current spikes and arcing, as well as reduced cutoff times.

Claims

1. A method of providing power to an electrosurgical instrument comprising:

generating a non-sinusoidal driving voltage having a substantially constant driving frequency;

providing the non-sinusoidal driving voltage to an LC circuit having a resonant frequency of substantially twice the substantially constant driving frequency;

generating a quasi-sinusoidal current in the LC circuit from the non-sinusoidal driving voltage; and

providing the quasi-sinusoidal current to an electrical output, wherein the electrical output is configured for coupling to an electrical input of a surgical instrument.

2. The method of claim 1, further comprising, presenting an impedance to the quasi-sinusoidal current in the LC circuit that limits current spikes.

3. The method of claim 1, wherein the non-sinusoidal driving voltage is a pulsed waveform.

4. The method of claim 3, wherein the non-sinusoidal driving voltage is a square wave.

5. The method of claim 4, further comprising discharging substantially all energy stored in the LC circuit during a time period that occurs once per resonant cycle of the LC circuit.

6. The method of claim 5, further comprising discharging substantially all energy stored in the LC circuit during the time period that occurs once per resonant cycle of the LC circuit so that the quasi-sinusoidal current in the LC circuit approaches 0 amperes during switching of the square wave.

7. The method of claim 6, wherein the time period is a second half of each half cycle of the square wave.

8. A power supply for an electrosurgical instrument comprising:

a power provider configured to provide a non-sinusoidal voltage at a substantially constant driving frequency and a variable amplitude;

an LC circuit configured to receive the non-sinusoidal voltage and provide a quasi-sinusoidal current, and wherein the resonant frequency of the LC series circuit is substantially twice that of the substantially constant driving frequency; and

an electrical output configured to provide the quasi-sinusoidal current to an electrosurgical instrument.

9. The power supply of claim 8, wherein the power supply includes a power source in series with a pulse generator.

10. The power supply of claim 9, wherein the power source includes a buck-boost converter configured to provide and receive DC current to and from the pulse generator, where the amplitude of the DC current controls the variable amplitude of the power provider.

11. The power supply of claim 10, wherein the pulse generator includes an h-bridge for receiving and providing the DC current from and to the buck-boost converter via a DC bus, and providing pulsed voltage to the LC circuit at the substantially constant driving frequency.

12. The power supply of claim 11, wherein the pulsed voltage is a square wave.

13. The power supply of claim 12, wherein:

energy passes from the DC bus to the h-bridge and to the LC circuit during a first half of each pulse of the square wave; and

energy passes from the LC circuit to the h-bridge to the DC bus during a second half of each pulse of the square wave.

14. The power supply of claim 13, wherein the LC circuit presents an impedance that limits current spikes in the quasi-sinusoidal current.

15. The power supply of claim 13, wherein the LC circuit discharges substantially all energy stored therein to the DC bus during the second half of each pulse of the square wave.

16. A power supply for an electrosurgical instrument comprising:

a power source configured to provide DC power at a variable amplitude;

a pulse generator configured to receive the DC power and produce pulsed voltage at a substantially constant driving frequency and at an amplitude dependent upon the variable amplitude of the power source;

an LC circuit comprising an inductive component and a capacitive component in series, the LC circuit configured to receive the pulsed voltage from the pulse generator and generate a quasi-sinusoidal current that returns energy to the pulse generator and the power source when the pulsed voltage and the quasi-sinusoidal current are of opposite polarity; and

an electrical output configured to provide the quasi-sinusoidal current to an electrosurgical instrument.

17. The power supply of claim 16, wherein the power source and pulse generator both source and absorb power.

18. The power supply of claim 16, wherein the power source operates in a constant power mode to maintain a desired power.

19. The power supply of claim 16, wherein the power source includes a buck-boost converter.

20. The power supply of claim 16, wherein the pulse generator includes an h-bridge.

21. The power supply of claim 16, wherein a resonant frequency of the LC circuit is substantially twice the substantially constant driving frequency.

22. The power supply of claim 16, wherein the LC circuit provides an impedance to the quasi-sinusoidal current.

23. A method of providing power to an electrosurgical instrument comprising:

generating a non-sinusoidal driving voltage having a substantially constant driving frequency;

providing the non-sinusoidal driving voltage to an LC circuit, wherein the first generating and providing is performed via a power provider;

generating a quasi-sinusoidal current from the non-sinusoidal driving voltage;

periodically discharging the LC circuit by returning energy to the power provider; and

providing the quasi-sinusoidal current to an electrical output, wherein the electrical output is configured for coupling to an electrical input of a surgical instrument.

24. The method of claim 23, wherein energy is returned to the power provider for a period of time during each cycle of the quasi-sinusoidal current.

25. The method of claim 24, wherein the non-sinusoidal driving voltage is pulsed.

26. The method of claim 25, wherein the period of time is a second half of each cycle of the quasi-sinusoidal current.