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Control circuit for electrosurgical units

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US3913583A
US3913583A US47566874A US3913583A US 3913583 A US3913583 A US 3913583A US 47566874 A US47566874 A US 47566874A US 3913583 A US3913583 A US 3913583A
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patient
control
current
circuit
reactor
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William T Bross
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Castle Co
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Sybron Corp
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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/1206Generators therefor
    • A61B18/1233Generators therefor with circuits for assuring patient safety
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B18/00Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body
    • A61B18/04Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating
    • A61B18/12Surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body by heating by passing a current through the tissue to be heated, e.g. high-frequency current
    • A61B18/14Probes or electrodes therefor
    • A61B18/16Indifferent or passive electrodes for grounding
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/04Detecting, measuring or recording bioelectric signals of the body or parts thereof
    • A61B5/0402Electrocardiography, i.e. ECG
    • A61B5/0408Electrodes specially adapted therefor
    • A61B5/0424Protection against electrode failure
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S323/00Electricity: power supply or regulation systems
    • Y10S323/911Medical electronics

Abstract

A control circuit for electrosurgical units which controls power levels to patient electrode in response to load conditions thereof. A saturable reactor is connected in series between the output of the electrosurgical unit and the patient electrodes. The saturable reactor is biased by a control coil activated by a rectified current corresponding to the alternating current flowing between the patient electrodes which is an indication of the area of contact between the patient and one of the electrodes.

Description

United States Patent 'Bross Oct. 21, 1975 [54] CONTROL CIRCUIT FOR 3,699,967 10/1972 Anderson l28/303.14

ELECTROSURGICAL UNITS FOREIGN PATENTS OR APPLICATIONS Inventor: William BPOSS, Cincinnati, Ohio 1,439,302 l/1969 Germany 128/303.14 Assignee: Sybron Corporation, Rochester 642,239 5/1932 Germany 323/56 N.Y. I Primary ExaminerRichard A. Gaudet 22] Fled: June 1974 Assistant Examiner-Lee S. Cohen 2 APPL 475, 3 Attorney, Agent, or FirmTheodore B. Roessel; J.

Stephen Yeo [52] US. Cl. 128/303.l4; 323/6; 323/56;

330/8; 336/155 [571 ABSTRACT [51] Int. Cl. A6lB 17/36 A ontrol ir uit for electrosurgical units which conl Field Of 128/303J4, trols power levels to patient electrode in response to 33 /8; 6 load conditions thereof. A saturable reactor is connected in series between the output of the electrosur- References Cited gical unit and the patient electrodes. The saturable re- UNIT ED STATES PATENTS actor is biased by a control coil activated by a recti- 2,581,202 1/1952 Post 336/155 fied current crresponding the alternating current 2,735,979 2/1956 323,6 flowing between the patient electrodes which is an in- 2,856,498 l0/1958 Jones..... dication of the area of contact between the patient 3,061,828 10/1962 Hauck 323/6 and one of the electrodes. 3,601,126 8 1971 Estes 128 303.14 3,658,067 4/1972 Bross 128/303.14 7 Clams, 2 Drawlng Flgllres INDICATINGJ MEANS J 34 l l l l l 3,

US. Patent Oct. 21, 1975 OSCILLATOR MODULATION MEANS FIG. I

FROM OSCILLATOR ACTIVE PROBE l6 PALIgNT as W I? INDICATING MEANS PATIENT PLATE TO RECTIFIER DC OUTPUT FIG. 2

TO ACTIVE PROBE CONTROL CIRCUIT FOR ELECTROSURGICAL UNITS BACKGROUND OF THE INVENTION This invention relates generally to RF control circuits and more particularly concerns RF control circuits that are used in electrosurgical units. Electrosurgical units generate high frequency power for the cutting and collagulation of tissue under surgical conditions. The electrosurgical units supply a high frequency alternating current at power levels up to several hundred watts to electrodes usually consisting of an active probe and a relatively large dispersive plate generally known as a patient plate. The electrodes are available in various configurations to be selected by the surgeon according to the intended use. Alternating current enters at the surgical site from the active probe, passes through the body of the patient to the patient plate and then returns to the low or grounded terminal of the electrical surgical unit. The physiological effects produced by electrosurgery are a result of a very high current density at the interface of the surgical active probe and the body tissue. There are no physiological effects at the patient plate site because the same current flows out of the patient through a relatively large area. During an operation the active probe is placed in contact with the patient. The patient should be in continual electrical communication with the patient plate. In the case of low power coagulators, capacitive coupling between patient and ground is satisfactory. The current levels produced by high powered equipment, such as used in general and transurethral surgery require a direct contact patient plate return connection. In the latter situation there is potential danger associated with electrosurgery should the patient plate by improperly applied or if an initial electrical contact becomes interrupted. If there is no other ground connections and if no other part of the patient is in contact with electrical ground, the available surgical current will be so reduced that in most cases, the surgeon will be immediately aware of the problem and he would either stop the procedure and investigate or request that the power should'be increased. The latter could be dangerous as a subsequent return of electrical continuity would result in excessive power being dissipated at the surgical site. Also, should the resistance of the patient plate interface be high, any extraneous ground connection, such as a cardioscope ground lead, would act as a high frequency ground connection. The contact area of such an extraneous ground connection is likely to be too small for the magnitude of current present and a burn at this site is almost a certainty.

It is possible to include a monitoring device that insures high frequency continuity to the patient plate. However, this monitor cannot determine if the patient plate has sufficient area in contact with the patient. If

area contact isnt proper, some surgical current could is effective, but complicated because it requires filter circuits to prevent high frequency from adversely effecting electrosurgical device control circuitry.

It would be, therefore, highly desirable to provide a simpler control circuit,- either to be used alone or to supplement one of the prior types of patient plate monitoring systems to additionally determine whether the patient plate electrode is contacting the patient. Such a monitoring system should be passive and be able to reduce high frequency to a low value should there be a impedance condition at the patient plate interface or return cable.

It is the object of this invention to provide a new and improved control circuit for electrosurgical units to monitor the impedance of a patient plate interface and connecting cable.

It is also an object of this invention to provide a new and improved control circuit for electrosurgical units for controlling output as a function of contact area between patient and patient plate.

It is another object of this invention to provide a new and improved control circuit for connection in the output circuit of an electrosurgical unit for reducing high frequency current to a low value for sensing and increasing RF current to normal level only if a complete circuit exists between the active and the patient plate electrodes.

An additional object of this invention is to provide a new and improved control circuit for monitoring circuit conditions between active and patient plate electrodes and having a switching time in microseconds.

SUMMARY OF THE INVENTION A control circuit is disclosed that controls the high frequency output current of an electrosurgical unit as applied across patient electrodes in response to the load between said patient electrodes.

The control circuit includes a saturable reactor means having variable reactance windings connected in seriesbetween the electrosurgical unit and the active patient electrode. The high frequency return current is conducted through a bridge rectifier which produces a DC current which passes through a control winding of the saturable reactor. Under normal high frequency current flow the DC current will be sufficient to saturate the reactor, minimizing the impedance thereof. Should the high frequency current be less than normal the DC current will be correspondingly reduced, causing the reactor to appear as a series inductive reactance, further reducing the high frequency current flow. Since the reactor reactance is a function of patient to patient plate impedance, the control sequence requires that sufficient area'of contact be made between the patient and the patient plate electrode for the application of full power.

The saturable reactor means can include a three legged ferromagnetic core, with the variable reactance winding wound on the outer legs and connected so as to null out induced voltages that would adversely effect the control winding which is wound about the middle leg.

Electrostatic sheild material may be used between windings to prevent capacitive coupling.

An alternate construction of the variable reactor is to use two cores, which may be cup, U, vor toroid cores, each core having a variable reactance winding and a control coil.

Indicating means can be provided to alert the operator of the state of the variable reactor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of an electrosurgical unit which includes the control circuit of the invention.

FIG. 2 is an alternative embodiment of the control circuit of the invention.

DETAILED DESCRIPTION'OF THE DRAWING FIG. 1, an electrosurgical unit having an oscillator generates RF signals at hectowatt power levels. Such an oscillator may be a spark gap, a vacuum tube oscillator, or a solid state oscillator. Modulation means 12 are used by the surgeon to select the desired amplitude and modulation mode suitable to the surgical functions of the cutting, hemostasis, and coagulation which are dependent upon the shape of the output wave form. The oscillator 10 means also includes a activating switch which may be hand or foot operated. The output of the oscillator 10 goes to the control circuit 14 of the present invention and therefrom to patient electrodes comprising of an active probe 16 and a patient plate 17.

A saturable reactor 18 is used in the control circuit 14. The reactor 18 includes a three-legged magnetic core 20 substantially symmetrical. About the two outer legs 22, 24 of the core 20 are wound variable reactance windings 26, 28 having substantially equal number of turns. The variable reactance windings 26, 28 are wound and interconnected so as to cancel any induced voltage caused by magnetic flow in the core 20. The two variable reactance windings 26, 28 are connected in series with the output oscillator 10 of the electical surgical unit and the active probe l6.

About the center leg 30 of the core is wound a control winding 32.

The leads of the control winding 32 are connected to the DC terminals of a high frequency bridge rectifier 34. The AC terminals of the high frequency bridge rectifier are connected in series from the patient plate 17 to electrical ground through a first capacitor 36. A second capacitor 38 is placed across control winding 32 to level the ripple on the DC voltage. The amount of RF current passing through the patient will be dependent upon the impedance between the active probe 16 and the patient plate 17. The impedance is the sum of the patient resistance, typically between 400 and 500 ohms, and the interface resistance between the patient and the patient plate electrode 17. Should the patient plate 17 be improperly attached so as to have insufficient contact area between the patient and the patient electrode, the interface resistance will be high and the current at a given setting will be low campared to what it would be if the patient plate was correctly applied. The alternating RF current flows from the active probe 16 through the patient to the patient plate 17, through the high frequency rectifier 34 across the capacitor 36 to ground. The higher the amplitude of the RF current, the higher will be the rectified DC current passing through the control winding 32. Conversely, a poor connection will reduce the alternating RF current". The rectified DC current will be correspondingly lower reducing the current flowing through the control winding 32. When no DC current is present, the core material is unsaturated, and inductively loads the variable reactance windings 26, 28, effectively introducing a series reactance into the output circuit. This limits the output current to a low value typically..50 to milliamps when no DC control current is present. When a completed high frequency circuit is established, returning current passes through the rectified circuit 34, causing a DC current to flow through the reactor control winding 32 partly, saturating the core 20. This lowers the impedance of the reactance winding 26, 28 and increases the output current. The higher output current passes through the rectifier 34 further increasing the control winding current which completely saturates the reactor minimizing the reactance.

The core may be made of suitable ferromagnetic material such as ferrite. Unlike the usual saturable reactor it is not necessary for the core material to exhibit a square hysteresis loop. Details of the RF variable reactance windings include that the two coils are series connected but opposed so as to cancel any induced voltages in the DC control circuit. It is also important that the variable reactance windings 26, 28 are not coupled to the bias control circuit as RF passing through these windings could conceivably be coupled into the control winding 32 to be rectified by the high frequency rectifier 34 and affect the reactor. Therefore, electrostatic shield material 42 may be interposed between the outer 26, 28 and inner 30 legs to prevent capacitive coupling.

It would be desirable for the surgeon to be made aware of the condition of the control circuit. Indicating means 44 may be provided across the DC leads of the rectifier bridge circuit so as to be responsive to the amount of DC voltage and to provide indication thereof.

As shown in FIG. 2, an alternative method of making the saturable reactor is to use two cup cores 44, each having one RF winding 46 and one control winding 48 wherein the RF windings are connected so to cancel the induced voltage in the DC control winding. As herein defined, cup cores include U and toroid shaped cores.

The control circuit for disclosed units is a simple passive device that when connected in the output circuit of an electrosurgical unit, reduces high frequency current to a low value for sensing andincreases to normal level only if a complete circuit exists between the active probe and the patient plate. Switching time is in microseconds. Tests have been conducted with actual electrosurgical units using tubes, solid state and spark gap technologies over the frequency range of 500 kiloherz to 2.3 megaherz and the control circuit has been found to be both reliable and efficient.

I claim: i 1. In combination with an electrosurgical unit having an oscillator applying variable high frequency current to a plurality of patient electrodes, a control circuit comprising:

a saturable reactor connected between said oscillator and at least one of said patient electrodes; and

bias means responsive to current flow through said patient electrodes for biasing said saturable reactor to control the impedance thereof, whereby for a first range of current flow through said patient electrodes said saturable reactor represents an inductive reactance'to said oscillator and during a second range of current flow through said patient electrodes substantially greater than said first current flow said reactor represents a lower inductive reactance to said oscillator.

2. A control circuit as defined in claim 1, wherein said saturable reactor includes:

a ferromagnetic core;

a plurality of variable reactances windings, and

a control winding.

3. A control circuit as defined in claim 2, wherein said bias means includes:

a diode rectifying bridge connected between one of said patient electrodes and said control winding, said bridge having a DC current output corresponding to the amplitude of AC current flow, said DC output being applied to said control winding for biasing said saturable reactor.

4. A control circuit as defined in claim 3 which further includes an indicator means connected across said bias means so as to be indicative of said bias current and load conditions across said patient electrodes.

5. A control circuit as defined in claim 2, wherein said variable reactance windings are interconnected so as to nullify any induced voltage in said control winding.

6. A control circuit as defined in claim 5, which further includes an electrostatic shield means interposed between said variable reactance windings and said control windings.

7. A control circuit defined in claim 1, wherein said saturable reactor is comprised of:

two cup cores; at least one variable reactance winding wound abou each of said cup cores; and at least one DC control bias winding wound about each of said cup cores, whereas said variable reactance windings are connected in series so as to nullify the effect on said DC control coils winding.

UNITED STATES PATENT GFFICE CERTIFIQATE 0F COERECTEON Patent 3, 913, 583 I v D d October 21; 1975 Inventor(s) William T. Bross It is certified that error appears in the above-identified patent and that said Letters Patent: are hereby corrected as shown below:

Column 1, line 6L1- "exists" should be 7 --exits--. v

Column 2, line 63 "s heild" should be "Sm 91d".

Column 3, line 53 "camp ared" should be --compared--.

Signed and Scaled this tenth D3) Of February 1976 [SEAL] Arrest:

RUTH C. MA SON C. MARSHALL DANN Arresting Officer Commissioner ofParents and Trademarks UNITED STATES PATEP-ZT 0mm; CERTIFICATE 9F CGRRECHON Patent No, 3,913,583 Dated Octoloer 21,- 1975 Inventor(s) William T; Bross It is certified that error appears in the above-identified. patent and that said Letters Patent are hereby corrected as shown below: r

Column 1, line 6A "exists" should be --exits--.

Column 2, line 63 "s heild" 7 should be --sfii eld--,

Column 3, line 53 "campared" should be --compared--.

Engncd and Scaled this D tenth Day Of February 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Offive Commissioner oj'larents and Trademarks

Claims (7)

1. In combination with an electrosurgical unit having an oscillator applying variable high frequency current to a plurality of patient electrodes, a control circuit comprising: a saturable reactor connected between said oscillator and at least one of said patient electrodes; and bias means responsive to current flow through said patient electrodes for biasing said saturable reactor to control the impedance thereof, whereby for a first range of current flow through said patient electrodes said saturable reactor represents an inductive reactance to said oscillator and during a second range of current flow through said patient electrodes substantially greater than said first current flow said reactor represents a lower inductive reactance to said oscillator.
2. A control circuit as defined in claim 1, wherein said saturable reactor includes: a ferromagnetic core; a plurality of variable reactances windings, and a control winding.
3. A control circuit as defined in claim 2, wherein said bias means includes: a diode rectifying bridge connected between one of said patient electrodes and said control winding, said bridge having a DC current output corresponding to the amplitude of AC current flow, said DC output being applied to said control winding for biasing said saturable reactor.
4. A control circuit as defined in claim 3 which further includes an indicator means connected across said bias means so as to be indicative of said bias current and load conditions across said patient electrodes.
5. A control circuit as defined in claim 2, wherein said variable reactance windings are interconnected so as to nullify any induced voltage in said control winding.
6. A control circuit as defined in claim 5, which further includes an electrostatic shield means interposed between said variable reactance windings and said control windings.
7. A control circuit defined in claim 1, wherein said saturable reactor is comprised of: two cup cores; at least one variable reactance winding wound about each of said cup cores; and at least one DC control bias winding wound about each of said cup cores, whereas said variable reactance windings are connected in series so as to nullify the effect on said DC control coils winding.
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Cited By (99)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3964487A (en) * 1974-12-09 1976-06-22 The Birtcher Corporation Uncomplicated load-adapting electrosurgical cutting generator
FR2409487A1 (en) * 1977-11-17 1979-06-15 Valleylab Inc An apparatus and method for measuring the contact area with the tissues of an electrosurgical electrode and cryosurgery
US4184492A (en) * 1975-08-07 1980-01-22 Karl Storz Endoscopy-America, Inc. Safety circuitry for high frequency cutting and coagulating devices
US4303073A (en) * 1980-01-17 1981-12-01 Medical Plastics, Inc. Electrosurgery safety monitor
DE3239640A1 (en) * 1981-10-26 1983-05-19 Valleylab Inc Monitoring arrangement for a return electrode
US4494541A (en) * 1980-01-17 1985-01-22 Medical Plastics, Inc. Electrosurgery safety monitor
US4590934A (en) * 1983-05-18 1986-05-27 Jerry L. Malis Bipolar cutter/coagulator
US5335668A (en) * 1993-04-30 1994-08-09 Medical Scientific, Inc. Diagnostic impedance measuring system for an insufflation needle
US5413574A (en) * 1992-09-04 1995-05-09 Fugo; Richard J. Method of radiosurgery of the eye
US5417687A (en) * 1993-04-30 1995-05-23 Medical Scientific, Inc. Bipolar electrosurgical trocar
FR2735009A1 (en) * 1995-06-09 1996-12-13 Aquitaine Technologie Medical High-frequency current generator for tissue cutting or coagulation
US5611798A (en) * 1995-03-02 1997-03-18 Eggers; Philip E. Resistively heated cutting and coagulating surgical instrument
US5688269A (en) * 1991-07-10 1997-11-18 Electroscope, Inc. Electrosurgical apparatus for laparoscopic and like procedures
US5713896A (en) * 1991-11-01 1998-02-03 Medical Scientific, Inc. Impedance feedback electrosurgical system
US5772659A (en) * 1995-09-26 1998-06-30 Valleylab Inc. Electrosurgical generator power control circuit and method
WO1998047436A1 (en) * 1997-04-24 1998-10-29 Gyrus Medical Limited An electrosurgical instrument
EP1034747A1 (en) * 1999-03-05 2000-09-13 Gyrus Medical Limited Electrosurgery system and instrument
US6156036A (en) * 1999-06-11 2000-12-05 Alcon Laboratories, Inc. Surgical handpiece tip
US6162216A (en) * 1998-03-02 2000-12-19 Guziak; Robert Andrew Method for biopsy and ablation of tumor cells
US6211749B1 (en) * 1998-11-27 2001-04-03 Kyosan Electric Mfg. Co., Ltd. Impedance matching device
US6258085B1 (en) 1999-05-11 2001-07-10 Sherwood Services Ag Electrosurgical return electrode monitor
US6409725B1 (en) 2000-02-01 2002-06-25 Triad Surgical Technologies, Inc. Electrosurgical knife
US6589239B2 (en) 2000-02-01 2003-07-08 Ashok C. Khandkar Electrosurgical knife
WO2004028385A1 (en) 2002-09-25 2004-04-08 Sherwood Services Ag Multiple rf return pad contact detection system
US20040119577A1 (en) * 2002-12-20 2004-06-24 Robert Weger Coil arrangement with variable inductance
US20050192566A1 (en) * 2004-02-26 2005-09-01 Madden Sean C. Surgical handpiece tip
US20050273091A1 (en) * 2002-10-29 2005-12-08 Cathrxptyltd System for, and method of, heating a biological site in a patient's body
US20060041252A1 (en) * 2004-08-17 2006-02-23 Odell Roger C System and method for monitoring electrosurgical instruments
US20060041251A1 (en) * 2004-08-17 2006-02-23 Odell Roger C Electrosurgical system and method
US20060041253A1 (en) * 2004-08-17 2006-02-23 Newton David W System and method for performing an electrosurgical procedure
US7044948B2 (en) 2002-12-10 2006-05-16 Sherwood Services Ag Circuit for controlling arc energy from an electrosurgical generator
US7131860B2 (en) 2003-11-20 2006-11-07 Sherwood Services Ag Connector systems for electrosurgical generator
US7137980B2 (en) 1998-10-23 2006-11-21 Sherwood Services Ag Method and system for controlling output of RF medical generator
US7255694B2 (en) 2002-12-10 2007-08-14 Sherwood Services Ag Variable output crest factor electrosurgical generator
US20070222458A1 (en) * 2004-05-25 2007-09-27 Erbe Elektromedizin Gmbh Method And Measurement Apparatus For Determining The Transition Impedance Between Two Parts Of A Subdivided Neutral Electrode
US7300435B2 (en) 2003-11-21 2007-11-27 Sherwood Services Ag Automatic control system for an electrosurgical generator
US7303557B2 (en) 1998-10-23 2007-12-04 Sherwood Services Ag Vessel sealing system
US7364577B2 (en) 2002-02-11 2008-04-29 Sherwood Services Ag Vessel sealing system
USRE40388E1 (en) 1997-04-09 2008-06-17 Covidien Ag Electrosurgical generator with adaptive power control
US7396336B2 (en) 2003-10-30 2008-07-08 Sherwood Services Ag Switched resonant ultrasonic power amplifier system
US7473145B2 (en) 2001-06-01 2009-01-06 Covidien Ag Return pad cable connector
US7513896B2 (en) 2006-01-24 2009-04-07 Covidien Ag Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling
US20090112204A1 (en) * 2007-10-26 2009-04-30 Encision, Inc. Multiple Parameter Fault Detection in Electrosurgical Instrument Shields
US20090198229A1 (en) * 2008-02-05 2009-08-06 Tyco Healthcare Group Lp Hybrid Contact Quality Monitoring Return Electrode
US7628786B2 (en) 2004-10-13 2009-12-08 Covidien Ag Universal foot switch contact port
US7637907B2 (en) 2006-09-19 2009-12-29 Covidien Ag System and method for return electrode monitoring
US7648499B2 (en) 2006-03-21 2010-01-19 Covidien Ag System and method for generating radio frequency energy
US7651492B2 (en) 2006-04-24 2010-01-26 Covidien Ag Arc based adaptive control system for an electrosurgical unit
US7651493B2 (en) 2006-03-03 2010-01-26 Covidien Ag System and method for controlling electrosurgical snares
US7722603B2 (en) 2006-09-28 2010-05-25 Covidien Ag Smart return electrode pad
US7722601B2 (en) 2003-05-01 2010-05-25 Covidien Ag Method and system for programming and controlling an electrosurgical generator system
US7731717B2 (en) 2006-08-08 2010-06-08 Covidien Ag System and method for controlling RF output during tissue sealing
US7736359B2 (en) 2006-01-12 2010-06-15 Covidien Ag RF return pad current detection system
US7749217B2 (en) 2002-05-06 2010-07-06 Covidien Ag Method and system for optically detecting blood and controlling a generator during electrosurgery
US7766905B2 (en) 2004-02-12 2010-08-03 Covidien Ag Method and system for continuity testing of medical electrodes
US7780662B2 (en) 2004-03-02 2010-08-24 Covidien Ag Vessel sealing system using capacitive RF dielectric heating
US7794457B2 (en) 2006-09-28 2010-09-14 Covidien Ag Transformer for RF voltage sensing
US7834484B2 (en) 2007-07-16 2010-11-16 Tyco Healthcare Group Lp Connection cable and method for activating a voltage-controlled generator
US7880577B1 (en) * 2006-08-25 2011-02-01 Lockheed Martin Corporation Current doubler rectifier with current ripple cancellation
US7901400B2 (en) 1998-10-23 2011-03-08 Covidien Ag Method and system for controlling output of RF medical generator
US20110071520A1 (en) * 2009-09-23 2011-03-24 Tyco Healthcare Group Lp Methods and Apparatus for Smart Handset Design in Surgical Instruments
US20110077631A1 (en) * 2009-09-28 2011-03-31 Tyco Healthcare Group Lp Electrosurgical Generator User Interface
US7927328B2 (en) 2006-01-24 2011-04-19 Covidien Ag System and method for closed loop monitoring of monopolar electrosurgical apparatus
US7927329B2 (en) 2006-09-28 2011-04-19 Covidien Ag Temperature sensing return electrode pad
US7947039B2 (en) 2005-12-12 2011-05-24 Covidien Ag Laparoscopic apparatus for performing electrosurgical procedures
US7972328B2 (en) 2006-01-24 2011-07-05 Covidien Ag System and method for tissue sealing
US8007494B1 (en) 2006-04-27 2011-08-30 Encision, Inc. Device and method to prevent surgical burns
US8021360B2 (en) 2007-04-03 2011-09-20 Tyco Healthcare Group Lp System and method for providing even heat distribution and cooling return pads
US8034049B2 (en) 2006-08-08 2011-10-11 Covidien Ag System and method for measuring initial tissue impedance
US8080007B2 (en) 2007-05-07 2011-12-20 Tyco Healthcare Group Lp Capacitive electrosurgical return pad with contact quality monitoring
US8100898B2 (en) 2007-08-01 2012-01-24 Tyco Healthcare Group Lp System and method for return electrode monitoring
US8104956B2 (en) 2003-10-23 2012-01-31 Covidien Ag Thermocouple measurement circuit
US8147485B2 (en) 2006-01-24 2012-04-03 Covidien Ag System and method for tissue sealing
US8216220B2 (en) 2007-09-07 2012-07-10 Tyco Healthcare Group Lp System and method for transmission of combined data stream
US8216223B2 (en) 2006-01-24 2012-07-10 Covidien Ag System and method for tissue sealing
US8226639B2 (en) 2008-06-10 2012-07-24 Tyco Healthcare Group Lp System and method for output control of electrosurgical generator
US8231614B2 (en) 2007-05-11 2012-07-31 Tyco Healthcare Group Lp Temperature monitoring return electrode
US8251989B1 (en) 2006-06-13 2012-08-28 Encision, Inc. Combined bipolar and monopolar electrosurgical instrument and method
US20120239025A1 (en) * 2011-03-17 2012-09-20 Tyco Healthcare Group Lp Isolated Current Sensor
US8388612B2 (en) 2007-05-11 2013-03-05 Covidien Lp Temperature monitoring return electrode
US8486061B2 (en) 2009-01-12 2013-07-16 Covidien Lp Imaginary impedance process monitoring and intelligent shut-off
US8512332B2 (en) 2007-09-21 2013-08-20 Covidien Lp Real-time arc control in electrosurgical generators
US8663214B2 (en) 2006-01-24 2014-03-04 Covidien Ag Method and system for controlling an output of a radio-frequency medical generator having an impedance based control algorithm
US8685016B2 (en) 2006-01-24 2014-04-01 Covidien Ag System and method for tissue sealing
US8734438B2 (en) 2005-10-21 2014-05-27 Covidien Ag Circuit and method for reducing stored energy in an electrosurgical generator
US8753334B2 (en) 2006-05-10 2014-06-17 Covidien Ag System and method for reducing leakage current in an electrosurgical generator
US8777940B2 (en) 2007-04-03 2014-07-15 Covidien Lp System and method for providing even heat distribution and cooling return pads
US8777941B2 (en) 2007-05-10 2014-07-15 Covidien Lp Adjustable impedance electrosurgical electrodes
US8801703B2 (en) 2007-08-01 2014-08-12 Covidien Lp System and method for return electrode monitoring
US8808161B2 (en) 2003-10-23 2014-08-19 Covidien Ag Redundant temperature monitoring in electrosurgical systems for safety mitigation
US8821487B2 (en) 2005-03-31 2014-09-02 Covidien Ag Temperature regulating patient return electrode and return electrode monitoring system
US9116179B2 (en) 2012-12-17 2015-08-25 Covidien Lp System and method for voltage and current sensing
US9186200B2 (en) 2006-01-24 2015-11-17 Covidien Ag System and method for tissue sealing
US9314294B2 (en) 2008-08-18 2016-04-19 Encision, Inc. Enhanced control systems including flexible shielding and support systems for electrosurgical applications
US9474564B2 (en) 2005-03-31 2016-10-25 Covidien Ag Method and system for compensating for external impedance of an energy carrying component when controlling an electrosurgical generator
US9636165B2 (en) 2013-07-29 2017-05-02 Covidien Lp Systems and methods for measuring tissue impedance through an electrosurgical cable
US9833281B2 (en) 2008-08-18 2017-12-05 Encision Inc. Enhanced control systems including flexible shielding and support systems for electrosurgical applications
US9863983B2 (en) 2012-12-17 2018-01-09 Covidien Lp System and method for voltage and current sensing
US9872719B2 (en) 2013-07-24 2018-01-23 Covidien Lp Systems and methods for generating electrosurgical energy using a multistage power converter

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2581202A (en) * 1949-11-25 1952-01-01 Rca Corp Multistage variable-saturation tuning system and apparatus
US2735979A (en) * 1956-02-21 Input
US2856498A (en) * 1950-11-30 1958-10-14 Delapena & Son Ltd High frequency electric induction heating systems
US3061828A (en) * 1958-03-11 1962-10-30 Basic Products Corp Circuit means
US3601126A (en) * 1969-01-08 1971-08-24 Electro Medical Systems Inc High frequency electrosurgical apparatus
US3658067A (en) * 1969-05-19 1972-04-25 Sybren Corp Electro-surgical apparatus
US3699967A (en) * 1971-04-30 1972-10-24 Valleylab Inc Electrosurgical generator

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2735979A (en) * 1956-02-21 Input
US2581202A (en) * 1949-11-25 1952-01-01 Rca Corp Multistage variable-saturation tuning system and apparatus
US2856498A (en) * 1950-11-30 1958-10-14 Delapena & Son Ltd High frequency electric induction heating systems
US3061828A (en) * 1958-03-11 1962-10-30 Basic Products Corp Circuit means
US3601126A (en) * 1969-01-08 1971-08-24 Electro Medical Systems Inc High frequency electrosurgical apparatus
US3658067A (en) * 1969-05-19 1972-04-25 Sybren Corp Electro-surgical apparatus
US3699967A (en) * 1971-04-30 1972-10-24 Valleylab Inc Electrosurgical generator

Cited By (167)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3964487A (en) * 1974-12-09 1976-06-22 The Birtcher Corporation Uncomplicated load-adapting electrosurgical cutting generator
US4184492A (en) * 1975-08-07 1980-01-22 Karl Storz Endoscopy-America, Inc. Safety circuitry for high frequency cutting and coagulating devices
FR2409487A1 (en) * 1977-11-17 1979-06-15 Valleylab Inc An apparatus and method for measuring the contact area with the tissues of an electrosurgical electrode and cryosurgery
US4200104A (en) * 1977-11-17 1980-04-29 Valleylab, Inc. Contact area measurement apparatus for use in electrosurgery
US4303073A (en) * 1980-01-17 1981-12-01 Medical Plastics, Inc. Electrosurgery safety monitor
US4494541A (en) * 1980-01-17 1985-01-22 Medical Plastics, Inc. Electrosurgery safety monitor
DE3239640A1 (en) * 1981-10-26 1983-05-19 Valleylab Inc Monitoring arrangement for a return electrode
DE3249766C2 (en) * 1981-10-26 1988-08-18 Valleylab, Inc., Boulder, Col., Us Monitoring arrangement in a high-frequency surgical instrument
US4590934A (en) * 1983-05-18 1986-05-27 Jerry L. Malis Bipolar cutter/coagulator
US5688269A (en) * 1991-07-10 1997-11-18 Electroscope, Inc. Electrosurgical apparatus for laparoscopic and like procedures
US5713896A (en) * 1991-11-01 1998-02-03 Medical Scientific, Inc. Impedance feedback electrosurgical system
US5413574A (en) * 1992-09-04 1995-05-09 Fugo; Richard J. Method of radiosurgery of the eye
US5335668A (en) * 1993-04-30 1994-08-09 Medical Scientific, Inc. Diagnostic impedance measuring system for an insufflation needle
US5658279A (en) * 1993-04-30 1997-08-19 Medical Scientific, Inc. Bipolar electrosurgical trocar
US5417687A (en) * 1993-04-30 1995-05-23 Medical Scientific, Inc. Bipolar electrosurgical trocar
US5611798A (en) * 1995-03-02 1997-03-18 Eggers; Philip E. Resistively heated cutting and coagulating surgical instrument
FR2735009A1 (en) * 1995-06-09 1996-12-13 Aquitaine Technologie Medical High-frequency current generator for tissue cutting or coagulation
US5772659A (en) * 1995-09-26 1998-06-30 Valleylab Inc. Electrosurgical generator power control circuit and method
US6251106B1 (en) 1995-09-26 2001-06-26 Sherwood Services Ag Electrosurgical generator power control circuit and method
USRE40388E1 (en) 1997-04-09 2008-06-17 Covidien Ag Electrosurgical generator with adaptive power control
WO1998047436A1 (en) * 1997-04-24 1998-10-29 Gyrus Medical Limited An electrosurgical instrument
US6325799B1 (en) 1997-04-24 2001-12-04 Gyrus Medical Limited Electrosurgical instrument
US6162216A (en) * 1998-03-02 2000-12-19 Guziak; Robert Andrew Method for biopsy and ablation of tumor cells
US9168089B2 (en) 1998-10-23 2015-10-27 Covidien Ag Method and system for controlling output of RF medical generator
US7137980B2 (en) 1998-10-23 2006-11-21 Sherwood Services Ag Method and system for controlling output of RF medical generator
US7303557B2 (en) 1998-10-23 2007-12-04 Sherwood Services Ag Vessel sealing system
US8105323B2 (en) 1998-10-23 2012-01-31 Covidien Ag Method and system for controlling output of RF medical generator
US7901400B2 (en) 1998-10-23 2011-03-08 Covidien Ag Method and system for controlling output of RF medical generator
US8287528B2 (en) 1998-10-23 2012-10-16 Covidien Ag Vessel sealing system
US9113900B2 (en) 1998-10-23 2015-08-25 Covidien Ag Method and system for controlling output of RF medical generator
US6211749B1 (en) * 1998-11-27 2001-04-03 Kyosan Electric Mfg. Co., Ltd. Impedance matching device
EP1034747A1 (en) * 1999-03-05 2000-09-13 Gyrus Medical Limited Electrosurgery system and instrument
US6565559B2 (en) 1999-05-11 2003-05-20 Sherwood Services Ag Electrosurgical return electrode monitor
US6258085B1 (en) 1999-05-11 2001-07-10 Sherwood Services Ag Electrosurgical return electrode monitor
US6156036A (en) * 1999-06-11 2000-12-05 Alcon Laboratories, Inc. Surgical handpiece tip
US6589239B2 (en) 2000-02-01 2003-07-08 Ashok C. Khandkar Electrosurgical knife
US6409725B1 (en) 2000-02-01 2002-06-25 Triad Surgical Technologies, Inc. Electrosurgical knife
US7722412B2 (en) 2001-06-01 2010-05-25 Covidien Ag Return pad cable connector
US7473145B2 (en) 2001-06-01 2009-01-06 Covidien Ag Return pad cable connector
US7364577B2 (en) 2002-02-11 2008-04-29 Sherwood Services Ag Vessel sealing system
US7749217B2 (en) 2002-05-06 2010-07-06 Covidien Ag Method and system for optically detecting blood and controlling a generator during electrosurgery
EP2258295A2 (en) 2002-09-25 2010-12-08 Covidien AG Multiple RF return pad contact detection system
EP1719471A2 (en) 2002-09-25 2006-11-08 Sherwood Services AG Multiple RF return pad contact detection system
WO2004028385A1 (en) 2002-09-25 2004-04-08 Sherwood Services Ag Multiple rf return pad contact detection system
US7938825B2 (en) 2002-09-25 2011-05-10 Covidien Ag Multiple RF return pad contact detection system
US7871410B2 (en) * 2002-10-29 2011-01-18 Cathrx Ltd System for, and method of, heating a biological site in a patient's body
US20050273091A1 (en) * 2002-10-29 2005-12-08 Cathrxptyltd System for, and method of, heating a biological site in a patient's body
US8523855B2 (en) 2002-12-10 2013-09-03 Covidien Ag Circuit for controlling arc energy from an electrosurgical generator
US7255694B2 (en) 2002-12-10 2007-08-14 Sherwood Services Ag Variable output crest factor electrosurgical generator
US7824400B2 (en) 2002-12-10 2010-11-02 Covidien Ag Circuit for controlling arc energy from an electrosurgical generator
US7044948B2 (en) 2002-12-10 2006-05-16 Sherwood Services Ag Circuit for controlling arc energy from an electrosurgical generator
US20040119577A1 (en) * 2002-12-20 2004-06-24 Robert Weger Coil arrangement with variable inductance
US8298223B2 (en) 2003-05-01 2012-10-30 Covidien Ag Method and system for programming and controlling an electrosurgical generator system
US8303580B2 (en) 2003-05-01 2012-11-06 Covidien Ag Method and system for programming and controlling an electrosurgical generator system
US8267929B2 (en) 2003-05-01 2012-09-18 Covidien Ag Method and system for programming and controlling an electrosurgical generator system
US8080008B2 (en) 2003-05-01 2011-12-20 Covidien Ag Method and system for programming and controlling an electrosurgical generator system
US7722601B2 (en) 2003-05-01 2010-05-25 Covidien Ag Method and system for programming and controlling an electrosurgical generator system
US8012150B2 (en) 2003-05-01 2011-09-06 Covidien Ag Method and system for programming and controlling an electrosurgical generator system
US8104956B2 (en) 2003-10-23 2012-01-31 Covidien Ag Thermocouple measurement circuit
US8808161B2 (en) 2003-10-23 2014-08-19 Covidien Ag Redundant temperature monitoring in electrosurgical systems for safety mitigation
US8647340B2 (en) 2003-10-23 2014-02-11 Covidien Ag Thermocouple measurement system
US8113057B2 (en) 2003-10-30 2012-02-14 Covidien Ag Switched resonant ultrasonic power amplifier system
US8485993B2 (en) 2003-10-30 2013-07-16 Covidien Ag Switched resonant ultrasonic power amplifier system
US7396336B2 (en) 2003-10-30 2008-07-08 Sherwood Services Ag Switched resonant ultrasonic power amplifier system
US8966981B2 (en) 2003-10-30 2015-03-03 Covidien Ag Switched resonant ultrasonic power amplifier system
US9768373B2 (en) 2003-10-30 2017-09-19 Covidien Ag Switched resonant ultrasonic power amplifier system
US8096961B2 (en) 2003-10-30 2012-01-17 Covidien Ag Switched resonant ultrasonic power amplifier system
US7766693B2 (en) 2003-11-20 2010-08-03 Covidien Ag Connector systems for electrosurgical generator
US7416437B2 (en) 2003-11-20 2008-08-26 Sherwood Services Ag Connector systems for electrosurgical generator
US7131860B2 (en) 2003-11-20 2006-11-07 Sherwood Services Ag Connector systems for electrosurgical generator
US7300435B2 (en) 2003-11-21 2007-11-27 Sherwood Services Ag Automatic control system for an electrosurgical generator
US7766905B2 (en) 2004-02-12 2010-08-03 Covidien Ag Method and system for continuity testing of medical electrodes
US7276060B2 (en) 2004-02-26 2007-10-02 Alcon, Inc. Surgical handpiece tip
US20050192566A1 (en) * 2004-02-26 2005-09-01 Madden Sean C. Surgical handpiece tip
US7780662B2 (en) 2004-03-02 2010-08-24 Covidien Ag Vessel sealing system using capacitive RF dielectric heating
US7554341B2 (en) 2004-05-25 2009-06-30 Erbe Elektromedizin Gmbh Method and measurement apparatus for determining the transition impedance between two parts of a subdivided neutral electrode
US7425835B2 (en) 2004-05-25 2008-09-16 Erbe Elektromedizin Gmbh Method and measurement apparatus for determining the transition impedance between two parts of a subdivided neutral electrode
US20080278179A1 (en) * 2004-05-25 2008-11-13 Florian Eisele Method and measurement apparatus for determining the transition impedance between two parts of a subdivided neutral electrode
US20070222458A1 (en) * 2004-05-25 2007-09-27 Erbe Elektromedizin Gmbh Method And Measurement Apparatus For Determining The Transition Impedance Between Two Parts Of A Subdivided Neutral Electrode
US8758336B2 (en) 2004-08-17 2014-06-24 Encision, Inc. System and method for monitoring electrosurgical systems
US20060041253A1 (en) * 2004-08-17 2006-02-23 Newton David W System and method for performing an electrosurgical procedure
US7422589B2 (en) 2004-08-17 2008-09-09 Encision, Inc. System and method for performing an electrosurgical procedure
US20060041252A1 (en) * 2004-08-17 2006-02-23 Odell Roger C System and method for monitoring electrosurgical instruments
US20060041251A1 (en) * 2004-08-17 2006-02-23 Odell Roger C Electrosurgical system and method
US7465302B2 (en) 2004-08-17 2008-12-16 Encision, Inc. System and method for performing an electrosurgical procedure
US7628786B2 (en) 2004-10-13 2009-12-08 Covidien Ag Universal foot switch contact port
US8025660B2 (en) 2004-10-13 2011-09-27 Covidien Ag Universal foot switch contact port
US8821487B2 (en) 2005-03-31 2014-09-02 Covidien Ag Temperature regulating patient return electrode and return electrode monitoring system
US9474564B2 (en) 2005-03-31 2016-10-25 Covidien Ag Method and system for compensating for external impedance of an energy carrying component when controlling an electrosurgical generator
US9522032B2 (en) 2005-10-21 2016-12-20 Covidien Ag Circuit and method for reducing stored energy in an electrosurgical generator
US8734438B2 (en) 2005-10-21 2014-05-27 Covidien Ag Circuit and method for reducing stored energy in an electrosurgical generator
US8241278B2 (en) 2005-12-12 2012-08-14 Covidien Ag Laparoscopic apparatus for performing electrosurgical procedures
US7947039B2 (en) 2005-12-12 2011-05-24 Covidien Ag Laparoscopic apparatus for performing electrosurgical procedures
US7736359B2 (en) 2006-01-12 2010-06-15 Covidien Ag RF return pad current detection system
US9642665B2 (en) 2006-01-24 2017-05-09 Covidien Ag Method and system for controlling an output of a radio-frequency medical generator having an impedance based control algorithm
US8685016B2 (en) 2006-01-24 2014-04-01 Covidien Ag System and method for tissue sealing
US7927328B2 (en) 2006-01-24 2011-04-19 Covidien Ag System and method for closed loop monitoring of monopolar electrosurgical apparatus
US8475447B2 (en) 2006-01-24 2013-07-02 Covidien Ag System and method for closed loop monitoring of monopolar electrosurgical apparatus
US8663214B2 (en) 2006-01-24 2014-03-04 Covidien Ag Method and system for controlling an output of a radio-frequency medical generator having an impedance based control algorithm
US8267928B2 (en) 2006-01-24 2012-09-18 Covidien Ag System and method for closed loop monitoring of monopolar electrosurgical apparatus
US7513896B2 (en) 2006-01-24 2009-04-07 Covidien Ag Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling
US8147485B2 (en) 2006-01-24 2012-04-03 Covidien Ag System and method for tissue sealing
US8187262B2 (en) 2006-01-24 2012-05-29 Covidien Ag Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling
US8202271B2 (en) 2006-01-24 2012-06-19 Covidien Ag Dual synchro-resonant electrosurgical apparatus with bi-directional magnetic coupling
US7972328B2 (en) 2006-01-24 2011-07-05 Covidien Ag System and method for tissue sealing
US8216223B2 (en) 2006-01-24 2012-07-10 Covidien Ag System and method for tissue sealing
US9186200B2 (en) 2006-01-24 2015-11-17 Covidien Ag System and method for tissue sealing
US7972332B2 (en) 2006-03-03 2011-07-05 Covidien Ag System and method for controlling electrosurgical snares
US7651493B2 (en) 2006-03-03 2010-01-26 Covidien Ag System and method for controlling electrosurgical snares
US7648499B2 (en) 2006-03-21 2010-01-19 Covidien Ag System and method for generating radio frequency energy
US8556890B2 (en) 2006-04-24 2013-10-15 Covidien Ag Arc based adaptive control system for an electrosurgical unit
US9119624B2 (en) 2006-04-24 2015-09-01 Covidien Ag ARC based adaptive control system for an electrosurgical unit
US7651492B2 (en) 2006-04-24 2010-01-26 Covidien Ag Arc based adaptive control system for an electrosurgical unit
US8007494B1 (en) 2006-04-27 2011-08-30 Encision, Inc. Device and method to prevent surgical burns
US8753334B2 (en) 2006-05-10 2014-06-17 Covidien Ag System and method for reducing leakage current in an electrosurgical generator
US8251989B1 (en) 2006-06-13 2012-08-28 Encision, Inc. Combined bipolar and monopolar electrosurgical instrument and method
US7731717B2 (en) 2006-08-08 2010-06-08 Covidien Ag System and method for controlling RF output during tissue sealing
US8034049B2 (en) 2006-08-08 2011-10-11 Covidien Ag System and method for measuring initial tissue impedance
US7880577B1 (en) * 2006-08-25 2011-02-01 Lockheed Martin Corporation Current doubler rectifier with current ripple cancellation
US7637907B2 (en) 2006-09-19 2009-12-29 Covidien Ag System and method for return electrode monitoring
US7722603B2 (en) 2006-09-28 2010-05-25 Covidien Ag Smart return electrode pad
US8231616B2 (en) 2006-09-28 2012-07-31 Covidien Ag Transformer for RF voltage sensing
US8216222B2 (en) 2006-09-28 2012-07-10 Covidien Ag Temperature sensing return electrode pad
US8062291B2 (en) 2006-09-28 2011-11-22 Covidien Ag Smart return electrode pad
US7794457B2 (en) 2006-09-28 2010-09-14 Covidien Ag Transformer for RF voltage sensing
US7927329B2 (en) 2006-09-28 2011-04-19 Covidien Ag Temperature sensing return electrode pad
US20110190761A1 (en) * 2006-09-28 2011-08-04 Covidien Ag Temperature Sensing Return Electrode Pad
US8021360B2 (en) 2007-04-03 2011-09-20 Tyco Healthcare Group Lp System and method for providing even heat distribution and cooling return pads
US8777940B2 (en) 2007-04-03 2014-07-15 Covidien Lp System and method for providing even heat distribution and cooling return pads
US8235980B2 (en) 2007-05-07 2012-08-07 Tyco Healthcare Group Lp Electrosurgical system for measuring contact quality of a return pad
US8080007B2 (en) 2007-05-07 2011-12-20 Tyco Healthcare Group Lp Capacitive electrosurgical return pad with contact quality monitoring
US8777941B2 (en) 2007-05-10 2014-07-15 Covidien Lp Adjustable impedance electrosurgical electrodes
US8388612B2 (en) 2007-05-11 2013-03-05 Covidien Lp Temperature monitoring return electrode
US8690867B2 (en) 2007-05-11 2014-04-08 Covidien Lp Temperature monitoring return electrode
US8231614B2 (en) 2007-05-11 2012-07-31 Tyco Healthcare Group Lp Temperature monitoring return electrode
US8382749B2 (en) 2007-05-11 2013-02-26 Covidien Lp Temperature monitoring return electrode
US7834484B2 (en) 2007-07-16 2010-11-16 Tyco Healthcare Group Lp Connection cable and method for activating a voltage-controlled generator
US8801703B2 (en) 2007-08-01 2014-08-12 Covidien Lp System and method for return electrode monitoring
US8430873B2 (en) 2007-08-01 2013-04-30 Covidien Lp System and method for return electrode monitoring
US9539051B2 (en) 2007-08-01 2017-01-10 Covidien Lp System and method for return electrode monitoring
US8100898B2 (en) 2007-08-01 2012-01-24 Tyco Healthcare Group Lp System and method for return electrode monitoring
US8353905B2 (en) 2007-09-07 2013-01-15 Covidien Lp System and method for transmission of combined data stream
US8216220B2 (en) 2007-09-07 2012-07-10 Tyco Healthcare Group Lp System and method for transmission of combined data stream
US9271790B2 (en) 2007-09-21 2016-03-01 Coviden Lp Real-time arc control in electrosurgical generators
US8512332B2 (en) 2007-09-21 2013-08-20 Covidien Lp Real-time arc control in electrosurgical generators
US9757183B2 (en) 2007-10-26 2017-09-12 Encision Inc. Multiple parameter fault detection in electrosurgical instrument shields
US9254165B2 (en) 2007-10-26 2016-02-09 Encision, Inc. Multiple parameter fault detection in electrosurgical instrument shields
US8460284B2 (en) 2007-10-26 2013-06-11 Encision, Inc. Multiple parameter fault detection in electrosurgical instrument shields
US20090112204A1 (en) * 2007-10-26 2009-04-30 Encision, Inc. Multiple Parameter Fault Detection in Electrosurgical Instrument Shields
US20090198229A1 (en) * 2008-02-05 2009-08-06 Tyco Healthcare Group Lp Hybrid Contact Quality Monitoring Return Electrode
US8523853B2 (en) 2008-02-05 2013-09-03 Covidien Lp Hybrid contact quality monitoring return electrode
US8226639B2 (en) 2008-06-10 2012-07-24 Tyco Healthcare Group Lp System and method for output control of electrosurgical generator
US9833281B2 (en) 2008-08-18 2017-12-05 Encision Inc. Enhanced control systems including flexible shielding and support systems for electrosurgical applications
US9314294B2 (en) 2008-08-18 2016-04-19 Encision, Inc. Enhanced control systems including flexible shielding and support systems for electrosurgical applications
US8486061B2 (en) 2009-01-12 2013-07-16 Covidien Lp Imaginary impedance process monitoring and intelligent shut-off
US20110071520A1 (en) * 2009-09-23 2011-03-24 Tyco Healthcare Group Lp Methods and Apparatus for Smart Handset Design in Surgical Instruments
US8568400B2 (en) * 2009-09-23 2013-10-29 Covidien Lp Methods and apparatus for smart handset design in surgical instruments
US8652125B2 (en) 2009-09-28 2014-02-18 Covidien Lp Electrosurgical generator user interface
US20110077631A1 (en) * 2009-09-28 2011-03-31 Tyco Healthcare Group Lp Electrosurgical Generator User Interface
US20120239025A1 (en) * 2011-03-17 2012-09-20 Tyco Healthcare Group Lp Isolated Current Sensor
JP2012192189A (en) * 2011-03-17 2012-10-11 Tyco Healthcare Group Lp Isolated current sensor
US9116179B2 (en) 2012-12-17 2015-08-25 Covidien Lp System and method for voltage and current sensing
US9863983B2 (en) 2012-12-17 2018-01-09 Covidien Lp System and method for voltage and current sensing
US9366703B2 (en) 2012-12-17 2016-06-14 Covidien Lp System and method for voltage and current sensing
US9872719B2 (en) 2013-07-24 2018-01-23 Covidien Lp Systems and methods for generating electrosurgical energy using a multistage power converter
US9655670B2 (en) 2013-07-29 2017-05-23 Covidien Lp Systems and methods for measuring tissue impedance through an electrosurgical cable
US9636165B2 (en) 2013-07-29 2017-05-02 Covidien Lp Systems and methods for measuring tissue impedance through an electrosurgical cable

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