METHOD AND SYSTEM OF AN ELECTROSURGICAL CONTROLLER WITH WAVE-SHAPING

• US 20120296328A1
• Filed: 07/27/2012
• Published: 11/22/2012
• Est. Priority Date: 06/17/2009
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Marion, Duane W.
• Granted Patent: US 9,138,282 B2
• Time in Patent Office: Days
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/1286 having a specific transformer
• CPC Class Codes: A61B 2218/002 Irrigation
• CPC Class Codes: A61B 2218/007 Aspiration

Abstract

An electrosurgical controller with wave-shaping. At least some embodiments are methods including generating an alternating current (AC) voltage signal within an electrosurgical controller. The generating may be by inducing an intermediate AC voltage signal on a secondary winding of a first transformer, and wave-shaping the intermediate AC voltage signal by a second winding of a second transformer coupled to the first transformer, and thereby creating a final AC voltage signal. Thereafter, the method includes applying the final AC voltage signal to electrical pins of a connector configured to couple to an electrosurgical wand.

Claims

1. An electrosurgical controller comprising:

a wand connector configured to couple to a connector of an electrosurgical wand, and the wand connector comprising a plurality of electrical pins;

a voltage generator comprising;

a first transformer comprising a primary winding and a secondary winding, the secondary winding defines a first terminal coupled to a first electrical pin of the wand connector and a second terminal coupled to a second electrical pin of the wand connector;

a second transformer, different than the first transformer, the second transformer comprises a first winding and a second winding, and the second winding coupled to the secondary winding of the first transformer;

wherein the electrosurgical controller is configured to modify voltage of an alternating current (AC) signal induced on the secondary winding and applied to the first electrical pin relative to the second electrical pin, the modifying by selective control of the impedance of the second winding of the second transformer.

2. The electrosurgical controller of claim 1 wherein the electrosurgical controller is configured to modify the AC signal within only a portion of each half cycle of the AC signal.

3. The electrosurgical controller of claim 1 further comprising:

the first winding of the second transformer defines a first terminal and a second terminal;

an electrically controlled switch coupled to the first terminal, wherein electrical current flow in the first winding also flows through the electrically controlled switch; and

wherein the impedance of the second winding of the second transformer is controlled by selective control of electrical current flow through the electrically controlled switch.

4. The electrosurgical controller of claim 3 further comprising:

wherein the electrically controlled switch is a transistor;

a control circuit coupled to the transistor; and

wherein the control circuit is configured to drive the transistor between a conductive state and an off state at a frequency, and the impedance of the second winding is proportional to the frequency.

5. The electrosurgical controller of claim 3 further comprising:

wherein the electrically controlled switch is a transistor;

a control circuit coupled to the transistor; and

wherein the control circuit is configured to drive the transistor between a conductive state and an off state with a duty cycle, and the impedance of the second winding is proportional to the duty cycle.

6. The electrosurgical controller of claim 3 further comprising:

wherein the electrically controlled switch is a transistor;

a control circuit coupled to the transistor; and

wherein the control circuit is configured to drive the transistor to a state within an active region of the transistor, and the impedance of the second winding is proportional to the electrical current flow through the transistor.

7. The electrosurgical controller of claim 1 wherein the second winding of the second transformer is coupled in series with the secondary winding of the first transformer.

8. The electrosurgical controller of claim 1 wherein the second winding of the second transformer is coupled in parallel with the secondary winding of the first transformer.

9. The electrosurgical controller of claim 1 further comprising:

the first winding of the second transformer defines a first terminal and a second terminal;

a first transistor coupled to the first terminal;

a second transistor, different than the first transistor, coupled to the second terminal;

a control circuit coupled to the first and second transistors, wherein the control circuit is configured to force the first transistor to a conductive state during a positive half cycle of the AC signal induced on the secondary winding, and the control circuit is configured to force the second transistor to a conductive state during a negative half cycle of the AC signal; and

wherein the impedance of the second winding during the positive half cycle is proportional to the electrical current flow through first transistor; and

the impedance of the second winding during the negative half cycle is proportional to the electrical current flow through second transistor.

10. The electrosurgical controller of claim 9 wherein the electrosurgical controller is configured to modify the AC signal applied to the first electrical pin relative to the second electrical pin such that the AC signal has a direct current (DC) bias.

11. The electrosurgical controller of claim 9 wherein the first winding of the second transformer further comprises a center tap, and wherein the center tap is at least one selected from the group consisting of:

coupled to a ground;

coupled to a source of direct current (DC) voltage; and

electrically floated.

12. A system comprising:

a means for generating an alternating current (AC) signal, the AC signal applied to electrical pins of a means for connecting to an electrosurgical wand; and

a means for selectively modifying the AC signal, the means for selectively modifying coupled to the means for generating, and wherein the means for selectively modifying configured to apply and rescind modifications to the AC signal within a half-cycle of the AC signal.

13. The system of claim 12 wherein the means for selectively modifying further comprising:

a means for implementing a controlled impedance, the means for implementing coupled to means for connecting; and

a means for selectively controlling impedance of the means for implementing, the means for selectively controlling coupled to the means for implementing.

14. The system of claim 13 means for selectively controlling further comprises:

a first means for controlling electrical current flow coupled to the means for implementing; and

a second means for controlling electrical current flow coupled to the means for implementing;

wherein the first means for controlling is configured to enable and disable electrical current flow in a first half-cycle of the AC signal, and the second means for controlling is configured to enable and disable electrical current in a second half-cycle of the AC signal.