ELECTROSURGICAL GENERATORS AND SENSORS

• US 20160151106A1
• Filed: 12/02/2014
• Published: 06/02/2016
• Est. Priority Date: 12/02/2014
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Covidien LP (Medtronic Plc)
• Inventors: Buck, Dean C., BRANNAN, EDWARD L., Johnston, Mark A.
• Granted Patent: US 10,278,764 B2
• Time in Patent Office: Days
• 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 18/16 Indifferent or passive electrodes for grounding
• CPC Class Codes: A61B 2018/00077 high, i.e. electrically conducting
• CPC Class Codes: A61B 2018/00083 low, i.e. electrically insulating
• CPC Class Codes: A61B 2018/00827 Current
• CPC Class Codes: A61B 2018/00898 Alarms or notifications created in response to an abnormal condition
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils

Abstract

An electrosurgical generator includes a radio frequency output stage, a sensor for sensing current, and an active lead. The radio frequency output stage is configured to output at least one radio frequency waveform. The sensor includes a current sensor coil including an outer coil including an opening therethrough and an inner coil coupled to and disposed within the outer coil. The active lead is coupled to the radio frequency output stage and passes through the current sensor coil opening. The current sensor coil is configured to output a first signal indicative of a current within the active lead.

Claims

1. An electrosurgical generator, comprising:

a radio frequency output stage configured to output at least one radio frequency waveform, the radio frequency output stage including at least one active lead and at least one return lead, each of the at least one active lead and at least one return lead includes common-mode current and differential-mode current;

a sensor for sensing current, the sensor including;

a current sensor coil including;

an outer coil including an opening therethrough; and

an inner coil coupled to and disposed within the outer coil; and

wherein the at least one active lead and the at least one return lead pass through the current sensor coil opening such that the common-mode currents are canceled and the differential-mode currents are added.

2. The electrosurgical generator according to claim 1, wherein the current sensor coil is configured to output a signal indicative of the differential-mode currents.

3. The electrosurgical generator according to claim 1, wherein the current sensor coil is disposed within a printed circuit board.

4. The electrosurgical generator according to claim 3, wherein the sensor further includes at least one shielding member disposed over the outer coil.

5. The electrosurgical generator according to claim 4, wherein the printed circuit board includes:

a plurality of outer conductive traces each being coupled to the at least one active lead, the plurality of outer conductive traces being interconnected by at least one via through the printed circuit board.

6. The electrosurgical generator according to claim 5, wherein the printed circuit board includes:

a top dielectric layer;

a first dielectric intermediate layer;

a bottom dielectric layer; and

a second dielectric intermediate layer, and

wherein the outer coil includes;

a plurality of top conductive traces disposed between the top dielectric layer and the first dielectric intermediate layer of the printed circuit board;

a plurality of bottom conductive traces disposed between the bottom dielectric layer and the second dielectric intermediate layer of the printed circuit board, wherein the plurality of outer conductive traces are disposed over outer surfaces the bottom and top dielectric layers; and

a plurality of inner and outer vias interconnecting the pluralities of top and bottom conductive traces.

7. The electrosurgical generator according to claim 6, wherein the at least one shielding member is disposed over an outer dielectric layer disposed over the outer surface of at least one of the top dielectric layer or the bottom dielectric layer.

8. The electrosurgical generator according to claim 6, wherein the inner coil includes:

at least one conductive trace disposed within the outer coil and between the first and second dielectric intermediate layers of the printed circuit board.

9. The electrosurgical generator according to claim 2, wherein the current sensor coil includes diametrically opposed first and second ends and each of the outer coil and the inner coil includes first and second portions, the first and second portions being separated at the second end.

10. The electrosurgical generator according to claim 9, wherein the sensor further includes:

a fully-differential conditioning circuit configured to at least one of integrate, amplify, or filter the signal to output a processed signal indicative of the differential-mode currents.

11. The electrosurgical generator according to claim 10, wherein the conditioning circuit includes first and second terminals coupled to the first and second portions of the outer coil, respectively, and the first and second portions of the inner coil are coupled to a third terminal at the first end.

12. The electrosurgical generator according to claim 11, wherein the first portions of the outer coil and the inner coil are coupled to each other at the second end and the second portions of the outer coil and the inner coil are coupled to each other at the second end.

13. The electrosurgical generator according to claim 10, wherein the at least one active lead and the at least one return lead are symmetrically disposed over the current sensor coil about an axis defined between the first and second ends.

14. The electrosurgical generator according to claim 13, wherein the at least one active lead and the at least one return lead are disposed at a non-zero angle relative to the axis.

15. The electrosurgical generator according to claim 14, wherein the at least one active lead and the at least one return lead are disposed transversely relative to the axis.

16. An electrosurgical generator, comprising:

a radio frequency output stage configured to output at least one radio frequency waveform, the radio frequency output stage including at least one active lead and at least one return lead, each of the at least one active lead and at least one return lead includes common-mode current and differential-mode current;

a sensor for sensing current, the sensor including;

a current sensor coil defining an opening therethrough and diametrically opposed first and second ends, the current sensor coil including;

an outer coil including a first semi-circular portion and a second semi-circular portion; and

an inner coil disposed within the outer coil and including a first semi-circular portion and a second semi-circular portion, wherein the first semi-circular portions and the second semi-circular portions of the inner and outer coils are separated at the second end; and

wherein the at least one active lead and at least one return lead pass through the current sensor coil opening such that the common-mode currents are canceled and the differential-mode currents are added and the current sensor coil is configured to output a differential signal indicative of the differential-mode currents.

17. The electrosurgical generator according to claim 16, wherein the current sensor coil further includes at least one shielding member disposed over the outer coil and defining a second opening therethrough in alignment with the opening of the current sensor coil.

18. The electrosurgical generator according to claim 16, wherein the sensor further includes:

a conditioning circuit coupled to the inner and outer coils at the first end of the current sensor coil and configured to at least one of integrate, amplify, or filter the differential signal to output a processed signal indicative of the current.

19. The electrosurgical generator according to claim 16, wherein the at least one active lead and the at least one return lead are symmetrically disposed over the current sensor coil about an axis defined between the first and second ends of the current sensor coil.

20. The electrosurgical generator according to claim 19, wherein the at least one active lead and the at least one return lead are disposed at a non-zero angle relative to the axis.

21. The electrosurgical generator according to claim 20, wherein the at least one active lead and the at least one return lead are disposed transversely relative to the axis.