A control console that provides drive signals to the surgical instrument

Abstract

To provide a control console and a method for supplying a drive signal to a surgical instrument.SOLUTION: A control console 22 includes a transformer 90 having a primary coil 84 and a secondary coil 88. The primary coil receives an input signal from a power source 82 and induces a drive signal in the secondary coil so as to supply the drive signal 105 to a surgical instrument 28. A first current source having a leakage control coil 92 is connected to a route of the drive signal. The primary coil induces a first cancellation current to be injected inside the route of the drive signal so as to cancel a leakage current in the leakage control coil. A sensor 108 connected to the route of the drive signal outputs a detection signal 110 so as to provide feedback on the leakage current. The sensor can be connected to a second leakage current cancellation source and / or a disorder detection stage. The power source can be made variable, and can feed a current to a second current source as well.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure generally relates to a method for providing a drive signal to a powered surgical instrument, and more particularly to a method for providing a drive signal to a powered surgical instrument. Control consoles are designed to reduce patient leakage current from the signal / drive signals. Regarding Lu.

[0002] [CROSS-REFERENCE TO RELATED APPLICATIONS] This patent application is incorporated herein by reference in its entirety. Priority and all of the foregoing is claimed under U.S. Provisional Patent Application No. 62 / 595,235, filed December 6, 2007. Claim the benefits of [Background technology]

[0003] A powered surgical tool system can be thought of as having three basic components: The control console creates the second component of the system: the power generator. The power generator generates a drive signal having the characteristics required to operate the drive signal. Converting energy into another form of energy. Energy into which electrical energy is converted Types of energy include mechanical energy, thermal energy (heat), and photon energy (light). The third component of the instrument system is the energy applicator. The energy applicator receives the energy output by the power generator and Some instrument systems apply energy to target tissue to perform a specific therapeutic task. This type of system is designed to apply electrical energy that is directed at the target tissue. In this system, the power generator is essentially a conductor through which the drive signal is transmitted to the exposed electrical The electrodes are then energized and the electrical current is delivered to the tissue through the exposed electrodes. The electrodes are placed on the patient or integrated into the handpiece. Other implement systems are designed to provide mechanical energy. In this type of system, a power generator converts electrical energy, e.g., an AC drive signal, into a mechanical The energy is converted into vibrations, which are then applied to the patient through the handpiece.

[0004] An integral part of many surgical instrument systems is the surgical instrument, which is the handpiece At a minimum, the handpiece is designed to be held by the physician. It is a physical component that has an energy applicator extending from it. In most cases, the power generator is housed within the surgical instrument. Such a surgical instrument system is an ultrasonic surgical instrument system. The instrument includes a power generator that includes one or more drivers. Each driver receives an AC signal. The horn is mechanically coupled to the driver in close proximity. A tip that functions as an applicator extends distally from the horn. The vibrations promote similar vibrations in the horn and also in the tip. Vibrating Tip Against Tissue The movement of the tissue results in ablation, i.e., removal, of the tissue.

[0005] A unique feature that many powered surgical tool systems share with other powered assemblies is that The parasitic capacitance exists across the components of these systems. Capacitance is the capacitance that exists across two components under unequal voltages The presence of this capacitance results in a parasitic AC current flowing through one of the components. For example, a surgical instrument may be powered by a power generating unit to which an AC drive signal is applied. When equipped with a surgical instrument, the metallic structural components of the surgical instrument and the internal parts of the surgical instrument through which the current flows are through metal structural components due to parasitic capacitance between power generating components Parasitic currents can flow, which contribute to what is known as leakage current. Leakage current generally flows through components of a system to which current is applied for other purposes. More specifically, patient leakage current is the unintended flow of electrical current through the patient. This is the flow of current that cannot be detected.

[0006] During the procedure, it is possible that the patient could be inadvertently connected to earth ground. If the instrument is in use, leakage current can flow from the surgical instrument into the patient. To avoid danger, the powered surgical tool system must be earth grounded to the patient. should be designed to minimize leakage current through the patient in certain scenarios. When surgical instruments that may have leakage currents are applied to the patient, the leakage current This current could theoretically flow through the patient to this ground. It may have a negative impact on the functioning of government and organizations.

[0007] For these reasons, surgical instrument systems with surgical instruments intended to be applied to patients The stem is designed to ensure normal leakage current is less than 100µA. A surgical instrument system comprising a surgical instrument intended to be applied to cardiac tissue. The system is designed to have a normal leakage current of less than 10 microamps when used in the United States. These requirements are based on the IEC 60601 Medical Design Standard. The IEC 60601 standard is based on the IEC 60601 Design Standards. It also describes a process for testing powered surgical instruments to ensure compliance. do.

[0008] A further requirement is that the equipment applied to the patient cannot serve as a connection to earth. Mainly, if any voltage from another source is applied to the patient, the instrument will It should not serve as a connection to ground that would otherwise be passed through the patient.

[0009] The powered surgical tool system has outputs that are isolated from earth ground to prevent current leakage. However, the isolated output circuit alone cannot tolerate leakage. Some powered surgical tool systems are not sufficient to reduce the It has the ability to detect the path and reduce the peak output voltage of the system accordingly. This leads to some performance issues. The peak output voltage is To initiate the spark necessary for proper coagulation effect, leakage current must be minimized. Reducing the peak output voltage for this purpose may degrade the performance of the fixture system. Additionally, the amount of time required for the generator to detect an open circuit condition can cause instantaneous voltage This can lead to pressure spikes, which can cause leakage currents.

[0010] One way is to reduce the parasitic capacitance so as to reduce the parasitic current. If the ultrasonic surgical instrument is a surgical instrument, it may have a driver and a device intended to be vibrated by the driver. There is an electrical insulating insulation between the horn, which is one of the mechanical components of the surgical instrument being used. By providing an impedance disk, the parasitic capacitance can be reduced. The disadvantage associated with providing discs is that such discs can easily deflect the horn from the driver. This mechanical damping reduces the transmission of vibrations to the surgical tip. The efficiency of the equipment used decreases. Summary of the Invention [Problem to be solved by the invention]

[0011] Therefore, there is a need to address at least the above-mentioned technical shortcomings of conventional systems and methods. There is. [Means for solving the problem]

[0012] In one embodiment, a control console provides drive signals to the surgical instrument, and and a method for operating the control console. The control console includes a primary winding and a secondary winding. The transformer includes a primary winding adapted to receive an input signal from a power source and an external and configured to induce a drive signal in the secondary winding to provide the drive signal to the surgical instrument. The control console includes a first current source having a leakage control winding coupled to the path of the drive signal. The primary winding further comprises a leakage control winding configured to cancel out leakage current of the drive signal. The control circuit is configured to induce a first countercurrent to be injected into the path of the drive signal. The console also includes a sensor coupled to the path of the drive signal, the sensor detecting a voltage related to the leakage current. The sensor is configured to output a sense signal to provide feedback to the sensor.

[0013] In another embodiment, a control console that provides drive signals to the surgical instrument and a control system for controlling such a control console are provided. The control console includes a primary winding and a secondary winding. The primary winding is adapted to receive an input signal from a power source and to configured to induce a drive signal in the secondary winding to provide the drive signal to the appliance. The control console includes a first current source having a leakage control winding coupled to the path of the drive signal. The primary winding is further provided with a leakage control winding, which is driven so as to cancel out the leakage current of the drive signal. The sensor is configured to induce a first countercurrent to be injected into the path of the motional signal. , to detect a feature of an input signal and to output a detection signal related to the feature of the input signal. A second current source is coupled to the path of the drive signal. A variable gain device is coupled to the second current source. a variable gain device coupled to the current source and for selecting one of a plurality of leakage current adjustment settings; and to provide a selected leakage current adjustment setting to the variable gain device. The variable gain device is configured to receive the detection signal and to The second current source is configured to change the detection signal based on the leakage current adjustment setting. generates a second canceling current based on the modified sense signal from the variable gain device. and a second offset current is introduced into the path of the drive signal so as to offset the leakage current of the drive signal. It is configured to inject

[0014] In another embodiment, a control console that provides drive signals to the surgical instrument and a control system for controlling such a control console are provided. The control console includes a variable power supply, a transformer, and a method for operating the control console. The transformer includes a primary winding and a secondary winding. The primary winding is connected to a variable power supply. to receive an input signal from the variable power supply and to provide a drive signal to the surgical instrument. The current source is configured to induce a drive signal in the secondary winding to supply the drive current. The variable power supply is coupled to the path of the differential signal and to a variable power supply. The current source is configured to adjust the path of the drive signal so as to cancel out leakage current of the drive signal. It is configured to generate a countercurrent to be injected into the path.

[0015] These embodiments require the use of cumbersome additional devices that reduce the output power of the surgical instrument. This allows the control console to maintain low leakage current without the need for a and the ability to monitor the drive signal for leakage currents (which may prevent further leakage). control and fault detection stages) and / or to excite the drive signal to the leakage control source. It offers multiple benefits, including simplifying the control console by using a single power supply to power the The control console and methods described herein and their embodiments provide Further advantages will be appreciated with reference to the description provided herein.

[0016] The advantages of the present invention may be better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. This will be readily understood as the present invention becomes better understood. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 illustrates one embodiment of a powered surgical tool system including a control console and a surgical tool. [Figure 2]1 is a diagram of the operation of a leakage current measurement and cancellation feedback loop, according to one example. [Figure 3] FIG. 1 is a schematic diagram of two sources for canceling leakage current in a powered surgical tool system, according to one example. [Figure 4] FIG. 1 is a schematic diagram of an embodiment of a powered surgical tool system with a control console including two leakage current cancellation stages and current-based detection of leakage current. [Figure 5] FIG. 10 is a schematic diagram of another embodiment of a powered surgical tool system with a control console including two leakage current cancellation stages and voltage-based sensing of the drive signal. [Figure 6] 10 is a schematic diagram of an alternative embodiment of another embodiment of a powered surgical tool system with a control console including two leakage current cancellation stages and a technique for adjusting leakage current settings. [Figure 7] 1 is a schematic diagram of another embodiment of a powered surgical tool system with a control console including two leakage current cancellation stages and a leakage current fault detection stage. [Figure 8] FIG. 2 is a schematic diagram of the circuitry included in the fault detection stage according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] I. Overview Reference is made to the drawings, in which like numerals indicate like or corresponding parts throughout the several views. 2, a powered surgical tool system 20 is provided, and includes a control console 22 configured to provide a drive signal 105 to a surgical instrument 28. Has.

[0019] Reference will now be made to the exemplary embodiments illustrated in the drawings and specific language will be used to describe the embodiments. By using specific language to describe exemplary embodiments, It is not intended to limit the scope of the disclosure. Any modifications and further variations of the features of the invention exemplified herein that would normally occur to one skilled in the art are also contemplated. Modifications and any further applications of the principles of the present disclosure as illustrated herein are contemplated by the claims. should be considered within the scope of this disclosure.

[0020] A powered surgical tool system 20 will now be generally described with reference to FIG. The powered surgical tool system 20 will be referred to hereinafter as "system 20" for simplicity. The stem 20 carries a surgical instrument 28. The surgical instrument 28 may be an ultrasonic surgical instrument, or R The surgical instrument may be a surgical instrument for applying electrosurgical energy. The surgical instrument 28 may comprise a shell or body 30. The body 30 defines the medical portion of the surgical instrument 28. The body 30 forms the proximal end 29 of the surgical instrument. The term "proximal" refers to the side closest to the surgeon holding the surgical instrument and the The proximal end 29 is understood to mean the end farther from the site 33 where the surgical instrument 28 is applied. Opposite the distal end 31 of the surgical instrument 28 is located. and closer to the site 33 to which the surgical instrument 28 is applied. It is understood.

[0021] A control console 22 is part of the system 20. The control console 22 controls the surgical instruments. 28 is connected to a cable 32, which provides a drive signal 105 (described below). In embodiments where instrument 28 is an ultrasonic surgical instrument, cable 32 and external It is desirable to assemble the surgical instrument 28 into a single unit. These components include components that function as a surgical instrument 2 8 generates a drive signal 105, e.g., an AC signal, that is applied to the power generator 27 of the transformer. The power generator 27, also called a transducer, generates an AC signal from the type of surgical instrument to be applied to the patient. For example, in an ultrasonic surgical instrument 28, the power generator 27 converts electrical energy into Alternatively, the RF surgical instrument 2 may be a piezoelectric stack that converts energy into vibrations. In the device 8, electrical energy is applied directly to the patient through the electrodes, so a power generator 27 is not required. The surgical instrument 28 shown in FIG. 1 has a surgical instrument tip at its distal end 31. The surgical instrument is configured to apply ultrasonic or RF energy to the patient through the surgical energy The surgical instrument may be inserted into the patient's tissue 33 through an electrode or other surgical instrument other than those described herein. Regardless of the type of energy applied, the control console 2 2 is designed to minimize the possibility of leakage current into the patient's body.

[0022] A control interface 24 is connected to the control console 22. In FIG. The control interface 24 is a foot pedal. The state of the control interface 24 is displayed on the control console. The control interface 24 is monitored by a processor 35 in the control console 22. Regulating activation and / or specific control of surgical instrument 28 via sole 22 In FIG. 1, the control interface 24 is a user-operated control member. Shown as part of a foot pedal assembly that includes an irrigation pump, a suction pump, Or additional pedals can be used to control devices such as lights. Interface 24 may include configurations other than a foot pedal as shown in FIG.

[0023] The control console 22 may be a graphical user interface or a user interface such as a switch. The control interface 24 may further include a user interface 26. The interface 26 is monitored by a processor 35 within the control console 22. The user interface 26 allows the physician to control operating parameters for the surgical instrument 28. In ultrasound embodiments, such operating parameters include surgical The magnitude of the vibration amplitude of the instrument 28 can be mentioned.

[0024] The control interface 24 and user interface 26 provide commands to the system 20. It is understood to be a general representation of the means for inputting. In some configurations of the system 20, A single control unit can perform both functions, e.g. lever or footpeg. When the dial is first depressed, the system 20 causes the tip head of the surgical instrument 28 to Configuring system 20 so that the rod undergoes vibration cycles that are relatively small in amplitude As a result of successive depressions of the lever or foot pedal, the control console 22 , the surgical instrument 28 is subjected to a vibration cycle with a larger amplitude of the tip head. The applied drive signal 105 is reset.

[0025] The control console 22 may include a display 34. The image may be generated by a processor 35 in the control console 22. Information shown on the play 34 may include, but is not limited to, information related to the user interface 26. information identifying the surgical instrument 28 and the tip, and information regarding the operation, configuration, and operation of the system 20. The display 34 may include a touchscreen. In these versions, the display 34 By pressing the image of the button provided, the processor 35 in the control console 22 The display 34 displays the image and the processor 35 between the display 34 and the processor 35 to facilitate the input of commands to the Any suitable interface component may be provided. Further details regarding processors that can be used are provided in International Application PCT / US2016 / 031651, the contents of which are incorporated herein by reference in their entirety in International Publication No. WO 2016 / 183084 / US National Patent Application Publication No. No. 6,299,523, filed on Dec. 1, 2002, the contents of which applications are hereby incorporated by reference. The entire disclosure is incorporated herein by reference.

[0026] The processor 35 regulates the output of the drive signal 105 from the control console 22. The physician control input that sets the drive signal 105 through the processor 35 is connected to the control interface 24 and / or or based on the state of the user interface 26. Through the display 34 The input commands can also be used to control the settings of the drive signal 105. The characteristics of the drive signal 105 are based on data read from the memory of the surgical instrument 28. The characteristics of the drive signal 105 can be set by the control console 22. It is also employed as a feedback signal that further contributes to the setting of signal 105. Based on the input, the processor 35 outputs a signal that controls the drive signal 105 .

[0027] 4-7, the control console 22 includes a power supply 82 or is otherwise The transformer 90 is coupled to a power supply 82 which applies an input signal to a primary winding 84 of the transformer 90. The input signal from the power supply 82 is fed to the sensor of the primary winding 84 of the transformer 90. The transformer 90 electrically isolates the patient circuit from the power supply 82. The voltage regulator 90 prevents any DC component of the signal in the primary winding 84 from being transmitted to the secondary winding 88. 4-7 as core 98 to minimize capacitive coupling. It can be designed to have a body.

[0028] The taps at both ends of the primary winding 84 are each coupled to a linear amplifier 86. 6 applies an AC signal of varying potential and frequency to the taps of the primary winding 84. The base signal applied to the amplifier 86 as a control signal is the signal output by the amplifier 86. In one embodiment, the system 20 includes an ultrasonic surgical instrument 28. Now, the AC signal generated across the primary winding 84 has a frequency between 10 kHz and 100 kHz. The signal may have a peak-to-peak voltage of at least 200 volts or more. In other applications, such as RF treatment, the AC signal may have a voltage. The frequency and voltage ranges may be other than those mentioned above.

[0029] The structure of the power supply 82 and the linear amplifier 86 is not limited to the specific embodiment shown herein. , may include different configurations for generating an AC signal across the primary winding 84. Further understanding of this subassembly can be found in International Application No. PCT / US2016 / 031651. The content of the application is as follows: WO 2016 / 183084 / U.S. Patent Application Public release Nos. 6,299,262, 6,29 ... This document shall form part of the Detailed Description.

[0030] The AC signal developed across the primary winding 84 is converted into an AC signal across the secondary winding 88 of the transformer 90. This signal across the secondary winding 88 of the transformer 90 is transmitted through the cable 32 to The drive signal 105 is applied to the power generator 27 in the surgical instrument 28. The cable 32 a high voltage side conductor 100 containing high potential current flowing toward the surgical instrument 28; and a low-voltage conductor 102 that carries a low-potential current flowing in a direction away from the drive signal 28. A path 104 (also called a "drive path") is defined by these conductors 100, 102. The drive signal 105 is a current passing through the drive path 104. In one embodiment used to operate a driver, the drive signal is at least 500V It has an AC voltage and can exceed 1000 VAC.

[0031] The drive path 104 is surrounded by a shield 99. The shield 99 is Prevent parasitic capacitance between conductor 100 and ground or any object near drive path 104. Additionally, a shield may be coupled to the low voltage side conductor 102 within the surgical instrument 28 . In embodiments where this connection is present, the shield 99 also serves as a secondary path for return current. This provides patient protection in the event of a break in the low voltage conductor 102.

[0032] II. Leakage Current Detection and Cancellation Techniques In accordance with the techniques described herein, the system 20 measures patient leakage current (also known as "leakage current"). Leakage cancellation techniques can be employed to cancel out leakage currents (referred to as leakage currents). The leakage current is the current flowing through the patient connected to the instrument 28. can flow from the patient to the surgical instrument 28 and then to earth ground. Leakage current is generally the unintended flow of electrical current through a patient.

[0033] As will be appreciated from the examples provided herein, the system 20 may utilize active control and A combination of active and passive control may be used to employ leakage current cancellation. Control techniques employ elements that make decisions based on input or feedback signals. Dynamic control techniques passively provide leakage current cancellation without making active decisions. Active control techniques complement active devices by employing elements such as resistors, capacitors, and inductors. Among these active and passive leakage current cancellation systems, One or more may be included in the control console 22 .

[0034] In one embodiment shown in FIG. 3, a first source 68' and a second source 68' are provided to cancel leakage current. An equivalent circuit illustrating the operation of the source 74' is provided. The first source 68' is passive and , AC voltage source. The second source 74' is active and is shown as a variable AC voltage source. The first source 68' generates a first canceling current 80' and the second source 74' generates a To this end, the first source 68' and the second source 7 4' in that they generate canceling currents 80' and 122', respectively, as shown in FIG. Current Sources The sources 68', 74' are referred to herein as current sources.

[0035] A power supply indicator 56 (comprising a power supply 82 and a transformer 90) supplies a drive signal 1 for the surgical instrument 28. The offset currents 80', 122' are generated by these sources 68', 74'. and injected into the drive signal 105 or into the path 104 of the drive signal 105 .

[0036] In this equivalent schematic, the first current source 68' is illustrated in series with a capacitor 70. , the second current source 74' is in series with a capacitor 76. Resistor 66 represents the known impedance of instrument 28 and the variable impedance through surgical site 33. capacitors 60 and 64 represent the impedance of the high voltage conductor 100 and the low voltage conductor 110, respectively. represents the capacitance to the conductor 102. Such capacitance may be parasitic, This results in a leakage current 62. In this example, the leakage current in the drive signal 105 The leakage current 62 travels through the capacitor 60 .

[0037] According to the IEC 60601 medical design standard, the powered surgical tool system 20 must The power supply voltage should be maintained at 100 μA or less. If designed for use on or near a fabric, the maximum leakage current is 10 µA. They are a pair.

[0038] In some embodiments, the first current source 68' may be configured to provide a majority (e.g., 5 The second current source 74' is designed to offset the first offset current (0% to 90%). 3, which cancels at least some of the residual leakage current 62 remaining after the cancellation by current 80'. 2. Such residual leakage current 62 generates a countervailing current 122′ of, for example, the total leakage current 62. In one example, the first current source 68' may be 1% to 40% of Residual leakage current, for example, ±40µA patient leakage current, leaving ±500µA maximum patient leakage current In another example, the second current source 74' can be designed to cancel the leakage current. Most of the leakage current 62 can be canceled out.

[0039] In an ideal control console 22, the leakage current 62 of the drive signal 105 is a first offset current 80′ plus a second offsetting current 122′. Active or passive current sources, any combination of active and / or passive current injection sources Any of these groups, or any combination thereof, can be used.

[0040] As will be appreciated from the embodiments described herein, the second (active) current source 74 is 2. The offset current 122 is generated by the inverter 121. Such additional components may include, for example, a second counterbalancing current 122. This can help determine how or when to generate the The phrase "second current source" in this document is limited to current generating components only. do not have.

[0041] 4-7, further aspects of the first current source 68 and the second current source 74 will be described. The first current source 68 may also be referred to as a matched current source. The first current source 68 in this configuration includes a leakage control winding 92. The leakage control winding 92 is The transformer 90 includes a leakage control winding 92. In this case, the leakage control winding 92 can be integrated with the transformer 90. An example of how both the capacitor 94 and the transformer 90 can be integrated is given in International Application PCT / US2017 / 034437, the contents of which are incorporated herein by reference in their entirety. No. 6,299,523, the contents of which are incorporated herein by reference in their entireties. The first current source 68 may also include a capacitor 96.

[0042] A current is induced across the leakage control winding 92 by the primary winding 84. The conduction facilitates the generation of a first cancellation current 80 by the first current source 68. Current 80 is injected into the low voltage conductor 102 of the drive signal path 104. A first cancellation current 80 is shown injected into the side conductor 102 to cancel the leakage current 62. In addition, a counter-current of opposite polarity can be injected into the high voltage side conductor 100. In an embodiment in which the driver 22 includes a transformer 90 through which the drive signal 105 is generated, the first current source One or all of the components forming 68 may be combined into a single unit with transformer 90. It can be constructed.

[0043] Further details regarding the construction of the transformer 90 and the first current source 68 are found in International Application PCT / US The contents of that application can be found in International Publication No. 2017 / 034437. No. 6,299,523, the contents of which application have been previously incorporated by reference.

[0044] A. Closed-loop leakage current cancellation control 2, 4, 5 and 7, it is possible to cancel at least some of the leakage current 62. Regarding the embodiment of the second current source 74 employed by the control console 22 to In one example, the second current source 74 is configured to absorb at least some of the leakage current 62. feedback, which can be a measurement of the current or voltage of the drive signal 105, Use the signal.

[0045] The cancellation of leakage current 62 by using a feedback signal is illustrated in the control loop of FIG. One or more sensors 36 measure characteristics of the drive signal 105 and measure the leakage current 62. The detection signal 110' is a signal related to the leakage current 62. The target value can be a current, voltage, or any characteristic that exhibits a known or determinable relationship. 14' is set, which can be 0 or any other positive or negative value The target value 114' can be a target signal including a current amplitude or a voltage. The sense signal 110' and the target value 14' can include both AC and DC components. 14' is then differenced to generate error signal 44. In one embodiment, error signal 44 is calculated by summing the positive target value 114' with the negative of the sensed signal 110' by the summation stage 40. Instead of this summation process, the sensed signal 110' and the target value 114' are calculated as Many additional methods of determining the difference can be used.

[0046] The error signal 44 is multiplied by a gain device 46. The gain device 46 multiplies the error signal 44. The signal 44 can be increased, decreased, or left the same. The gain device 46 can be implemented as a circuit, software, or a combination of the two. , outputting a cancellation current 122′ that is injected into the drive signal 105 to cancel the leakage current 62. The human body model 50, which represents the surgical instrument 28 applied to the patient, includes a countervailing current 122'. The power is supplied by a drive signal 105 containing the +S×G), where G represents the gain 46 and S represents the sensed signal 110′. The principles illustrated in FIG. 2 are implemented in the surgical tool system 20 shown in FIGS. 4, 5 and 7. This is implemented in the embodiment.

[0047] 4-7 show surgical instrument systems related to reducing or eliminating leakage current 62. 4, 5 and 7 show the components of the stem 20. An embodiment is shown that includes a leakage current cancellation source 68 and an active (second) leakage current cancellation source 74 .

[0048] The second current source 74 receives two inputs: a sense signal 110 and a target value 114. In one embodiment shown in FIG. A transformer 106 is used to generate the detection signal 110. The transformer 106 is The primary winding of the transformer 106 is the drive path 104. In other words, the primary winding of the transformer 106 is The transformer 106 includes a high-voltage conductor 100 and a low-voltage conductor 102. The transformer 106 implements a sensor 108. It has a secondary winding that applies

[0049] The sensor 108 detects the common mode current in the drive path 104 and The common mode current is a leakage current. 62. The high voltage side conductor 100 is primarily The low voltage conductor 102 conducts current to the device, and the low voltage conductor 102 conducts current from the surgical instrument 28. These low voltage side current 100 and high voltage side current 102 are ideally equal in magnitude. When leakage current 62 exists, the current in high-voltage conductor 100 increases. The magnitude of the current in the low voltage conductor 102 is different from the magnitude of the current in the low voltage conductor 102. This difference in current Common mode current is a measure of current that flows in a single direction. If a common mode current exists across path 104, it will flow through the secondary winding, i.e., the In this embodiment, the high voltage conductor 10 generates a magnetic field that is sensed by the sensor 108. Only if there is some amount of current loss between the common mode conductor 100 and the low voltage conductor 102 Since there will be a common mode current, the common mode current will be the leakage current 6 of the drive signal 105. 2. In the absence of leakage current 62, the high voltage conductor 100 is In this case, the common Both the power supply current and the leakage current 62 in the powered surgical tool system are zero or substantially It is 0.

[0050] In FIG. 5, sensor 108 is replaced with sensor 126, shown as a capacitor. The sensor 126 senses the voltage in the low voltage conductor 102 of the drive path 104. When there is no current 62, the voltage on the low voltage conductor is 0 volts relative to the power supply 82; Or approximately 0 volts.

[0051] The shield 99 is also electrically connected to the low voltage conductor 102 of the surgical instrument 28. In an embodiment, the common mode current is instead the current in the high voltage side conductor 100 and the current in the low voltage side conductor 101. This is the difference between the current in the pressure side conductor 102 plus the current in the shield 99.

[0052] In Figures 4, 5 and 7, leakage current 62 leaks from drive signal 105 and takes a different path. To represent the current that travels through the low voltage conductor 102 to ground, This leakage current 62 is illustrated as a small opposing current due to capacitive coupling between elements of the system 20. and / or loss of electrical current in multiple ways and places throughout the system, including leakage of electrical current through the patient. Leakage current 62 is the result of current that may be lost. In some cases, the first counter current 80 and A second countervailing current 122 causes leakage current 62 to flow in the opposite direction to the direction of leakage current 62 shown in the figure. A leakage current 62 may result.

[0053] The sensed signal 110 is then fed to one or more amplifiers shown as amplifiers 112 in FIGS. The sense signal 110 can be changed by a second offsetting current 122. This is input to a second current source 74 for determination.

[0054] The second input to the second current source 74 is the target value 1 shown on the right side in FIGS. 14. The sensed signal 110 and the target value 114 are fed into a summing amplifier 118 with amplification 120. 4 and 7, the target value 114 is , which is a target current that is compared with the sense signal 110 to determine the second offset current 122. In this example, the target current is, for example, the ideal state where leakage current is eliminated. 5, the target value 114 may be, for example, 0 amperes, which represents a leakage current. The target voltage can be set to 0 volts, representing the ideal state where the current is removed. Other target values ​​114 than those described herein are contemplated and may be utilized. can be done.

[0055] As shown in Figures 4, 5 and 7, the power supply drives a second current source 74. In the illustrated example This is the same power supply 82 that energizes the transformer 90. The power supply 82 is a second current source 74, further aspects of which are described below. Alternatively, the second current source 74 The power supply that supplies power to the second offset current 1 can be different from the power supply 82. Since a DC power supply 82 is used to excite the 22, the target value 114 is set to some amount of D The target value 114 may have a C offset. The target value 114 is changed by the gain device 116. and then used as an input to a summing amplifier 118 that includes an additional amplification stage 120. A summing amplifier 118 with amplification 120 can be used to combine the target value 114 and the sensed signal 116. 10. A summing amplifier 118 with amplification 120 then subtracts the second cancellation current 1 Outputs 22.

[0056] Before the second counterbalancing current is injected into the drive path 104, any of the second counterbalancing current 122 In order to block the DC component from entering the drive path 104, a capacitor 124 is used. In some embodiments, the capacitor 124 uses a low capacitance. .

[0057] This second counterbalancing current 122 replaces the residual current remaining when the first counterbalancing current 80 is injected. This offsets at least some of the leakage current 62. Regardless of the type, the second counterbalancing current 122 is equal to the magnitude of the current in the low voltage conductor 102. to more closely match the magnitude of the current in the high voltage side conductor 100, and At this time, the voltage to the power supply 82 approaches 0 volts.

[0058] Undisclosed equivalents of the active leakage current cancellation techniques shown in FIGS. 4, 5, and 7 are fully contemplated. The schematic diagrams shown in Figures 4, 5 and 7 still provide suitable cancellation currents, as contemplated. may include additional or different components to those specifically illustrated. It can be done.

[0059] B. Open-loop leakage current cancellation control FIG. 6 illustrates another example of the second current source 74 used to generate the second cancellation current 122. In this embodiment, measurements from the drive signal 105 are not utilized. Additionally, a sensor 130 is included that measures the AC signal generated by the transformer 90. In this example, the AC signal is the voltage at the handpiece of the surgical instrument 28. The sensor 130 It may be part of the transformer 90 or may be added to the transformer 90. In the embodiment of FIG. In this example, the sensor 130 is a transformer winding.

[0060] The sensor 130 measures the AC signal generated across the transformer 90 and gains or reduces the sensed signal. The AC signal from the sensor 130 is sent to a gain stage 132 which scales the AC signal. The variable gain device 132 may be part of the second current source 74. or may be separate from the second current source 74.

[0061] A selection interface 134 is coupled to the second current source 74 and to the gain stage 132. The selection interface 134 allows selection of one of several leakage current adjustment settings. The leakage current adjustment setting is configured to allow user-selectable fine adjustment of the leakage current 62. The leakage current adjustment setting is looked up in the memory of the control console 22. The data can be stored in a table.

[0062] In the example shown in FIG. 6, the selection interface 134 is a potentiometer, which This may be an adjustable circuit or a digital potentiometer controlled by software. The selection interface 134 may also be used to select a desired item from the display 34 of the control console 22. This can also be done through the user interface in Other types of selection interfaces are contemplated that allow.

[0063] The selection interface 134 allows easier adjustment of the positive or negative leakage current. If the control console 22 complies with IEC 60601 or any additional Adjustments can be made to meet different standards.

[0064] The selection interface 134 is coupled to the sensor 130 through the first gain stage 132. The selection interface 134 receives the scaled version of the AC signal from the first gain stage 132. The selection interface 134 receives the selected version. A variable gain amplifier 138 that can adjust the gain from -1 to +1 based on an adjustment setting When the selection interface 134 is a potentiometer, the variable gain The amplifier 138 interfaces with the potentiometer to variably operate the potentiometer. The output 136 includes:

[0065] In one embodiment, the selection interface 134 is prepared as part of the manufacturing process. This allows for higher manufacturing tolerances and allows each control console 22 to minimize leakage current. This ensures that the minimum requirements are met.

[0066] The output of the amplifier 138 is supplied by a power source such as the power source 82 which is the power source for the drive signal 105. Alternatively, the second current source 74 may use a separate power supply. The amplifier 140 outputs the second cancellation current 122 to the drive signal path 104. The second cancellation current 122 is then applied to a capacitor 124 before being injected into the drive signal 104. This blocks DC.

[0067] Similar to the embodiments described in the preceding sections with respect to FIGS. 4, 5, and 7, In this embodiment, the second cancellation current 122 is generated by the first current source 68. 6. The leakage current 62 can be offset by the first offset current 80. Killing tweaks are provided.

[0068] Undisclosed equivalents of the active leakage current cancellation technique shown in FIG. 6 are fully contemplated. The schematic diagram specifically illustrates the current flow while still producing suitable cancellation currents, as contemplated. It may include additional or different components than those shown.

[0069] C. Variable power supply for the second current source For any of the embodiments described herein and shown in FIGS. 4-7, the transformer 90 The power supply 82 coupled to the primary winding 84 of the inverter may be a variable power supply. For example, power supply 82 has a variable output DC voltage level that can be set. In most cases, this voltage is between 25VDC and 250VDC. The voltage of the signal from power supply 82 is The power supply 82 is set based on the applied power supply control signal. A DC input signal can be applied to the center tap of the power supply 82. , can have a varying potential. Specifically, the potential of this input signal varies depending on the surgical instrument. 28 to vary as a function of the potential of the drive signal 105 to be applied to the power generator 27. can be set to.

[0070] This variable power supply 82 is connected to any of the second current sources 74 shown throughout the figure. can be used to power, drive, or otherwise provide input to The second current source 74 is coupled to the path of the drive signal 104 and is also coupled to the variable power supply 82. The variable power supply 82 is configured to energize the current source 74 (variable power supply 82) is applied to the drive signal to offset leakage current in the drive signal. 104. The offset current 122 is configured to be injected into the path 104.

[0071] Specifically, the DC input signal from the power supply 82 applied to the primary winding 84 is and the second current source 74 shown in FIG. 7 as an input to one or more of the amplifiers 120 or 140. Specifically, this DC input signal is converted by a second current source 74. to facilitate amplification of the signal generated by the This DC signal can be used as a positive voltage. In these versions, this DC signal is 4, 5 and 7, the second current source 74 may be applied as a signal. (shown as power supply 82 which supplies power to the stage that generates the target value 114). , including a feedback subcircuit that adjusts the target value 114 from the variable power supply 82, Therefore, this signal appears as a result of a change in the DC positive voltage applied to one or more amplifiers. In the embodiment shown in FIG. 6, the second current source 74 is connected to the amplifier 140. The power supply is supplied by a variable power supply 82.

[0072] The variable power supply 82 drives a second offsetting current 122. In one embodiment, this is This is the same power supply 82 that powers the drive path 104 to the surgical instrument 28. By using 2, the power required to drive the second counter current 122 is reduced by the drive signal This is advantageous because it varies proportionally with the power of No. 105. Alternatively, a separate power supply can be used. , which can drive the second leakage current source 74.

[0073] While it may be advantageous to reuse the variable power supply 82 to energize the leakage current cancellation source, The configuration may include a separate power supply that generates the second counterbalancing current 122 .

[0074] Variable power supply 82 may have configurations and capabilities other than those shown and described herein. Additionally, variable power supply 82 may be used with components of control console 22 other than those shown. It can be bound to the

[0075] D. Fault detection techniques for leakage current FIG. 7 adds a fault detection stage 144 that can be implemented in circuitry and / or software. This shows the same components as Figure 4.

[0076] The fault detection stage 144 is coupled to the sensor 106 or alternatively to the sensor 126 of FIG. The fault detection stage 144 receives the detection signal 110 from the sensors 106, 126 and detects the leakage current 6 2. The method of claim 1, wherein the fault detection signal 158 is configured to detect a fault condition associated with the are.

[0077] If the detection signal 110 indicates a level of leakage current 62 that exceeds a specified threshold, it This may be due to a fault in the system 20, such as a short circuit or connection to the patient's ground. If 62 is excessive, the fault detection stage 144 detects a fault on the GPIO (general purpose input / output) line. Triggers the harm detection signal 158.

[0078] A controller 160 is coupled to the fault detection stage 144, for example at a GPIO line. 144. The fault detection stage 144 is adapted to receive a fault detection signal 158 from the fault detection stage 144. The fault detection signal 158 is adapted to receive a leakage current 6 2. The controller 160 is configured to issue instructions Algorithms stored in memory that process or control the operation of the control console 22 Additionally or alternatively, the device may have one or more microprocessors for processing the logic. Typically, the controller 160 may include one or more microcontrollers, a field programmer, A gate array, a system on a chip, a discrete circuit, and / or Any other suitable hardware, software, or firmware capable of performing the functions described. The fault detection stage 144 and the controller 160 may be coupled It can be a combined element or a separate element.

[0079] The fault detection stage 144 is configured to detect the presence of a fault detection signal 158 for a predetermined period of time, and When the predetermined period is reached, a fault detection signal 158 is sent to the controller 160. The fault detection stage 144 is configured to ensure that persistent faults are detected and , so as to avoid false alarms based on very small or intermittent signal spikes. This can be done.

[0080] The controller 160 receives the fault detection signal 158 from the GPIO line and The controller is configured to compare the output signal 158 with a target value to determine a fault condition. The controller 160 reduces or terminates power to the surgical instrument 28 in response to the determination of the fault condition. The controller 160 may be connected to a control console other than those described herein. Other responses to the rule 22 or surgical instrument 28 may be triggered.

[0081] 8 illustrates one embodiment of the fault detection stage 144. In some particular embodiments, The fault detection stage 144 detects whether the sensed common mode current or low side voltage exceeds a specified level. The sense signal 110 is modified by an amplifier 112. This amplifier 112 is used to generate a second cancellation current 122. This may be the same as the first gain stage used in the first gain stage, or it may be a separate gain device. The sensed signal 110 is then provided to a low pass filter 146 and a rectifier 148. The low pass filter 146 removes higher frequency signals above a specified threshold. The low pass filter 146 attenuates signals that are relatively close to the filter frequency. A gain device, shown as amplifier 148, can be used to accommodate any attenuation. During a fault condition, the sense signal 110 is , a pulse is emitted every drive period (for example, when the drive signal 105 is at its maximum amplitude, the sensor The common mode current sensed by the sensor 108 is at a maximum and the drive signal 105 is at a minimum amplitude. (When the width is 1 / 3, the common mode current approaches 0.) A filter is placed in place to hold the fault condition at its maximum level between pulses. The RC time constant of the filter is the capacitance of capacitor 150 multiplied by the resistance of resistor 152. The fault signal is then output to the inverter 154, which , inverting the applied signal to output a fault signal 158 to the controller 160. The controller 160 monitors this signal and takes action as necessary if a fault condition exists for a specified period of time. The system can then take appropriate action. The operator of the surgical instrument 28 is alerted via the display 34, and the power supply 8 reducing the power output by the surgical instrument 28 and / or cutting off power to the surgical instrument 28; Examples include:

[0082] The fault detection stage 144, the controller 160 and their components are described herein. While still embodying the ability to detect leakage current faults as described herein, It may be different from that listed.

[0083] Several embodiments have been discussed in the above description. However, the embodiments discussed herein are It is not intended to be exhaustive or to limit the present invention to any particular form. The terms used are in the nature of words of description rather than limiting. Many modifications and variations are possible in light of the above teachings and may be practiced in accordance with the present invention. may be implemented in ways other than those specifically stated.

[0084] The numerous features and advantages of the present invention are apparent from the detailed specification, and it is, therefore, intended by the appended claims to cover all such features and advantages of the present invention that fall within the true spirit and scope of the invention. Further, because numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation as illustrated and described, and therefore, all suitable modifications and equivalents may be employed that fall within the scope of the invention. In order to maintain the disclosure of the present application as originally filed, the contents of claims 1 to 46 as originally filed are added below. (Claim 1) a control console for providing a drive signal to a surgical instrument, a transformer having a primary winding and a secondary winding, the primary winding configured to receive an input signal from a power source and to induce the drive signal on the secondary winding to provide the drive signal to the surgical instrument; a first current source having a leakage control winding coupled to a path of the drive signal, the primary winding configured to induce in the leakage control winding a first cancellation current to be injected into the path of the drive signal to cancel a leakage current of the drive signal; a sensor coupled to the path of the drive signal, the sensor configured to output a sense signal to provide feedback related to leakage current; A control console comprising: (Claim 2) The control console of claim 1 , wherein the power supply is a variable power supply. (Claim 3) 3. The control console of claim 1, wherein the transformer and the first current source are integrated into a single package. (Claim 4) 4. The control console of claim 1, wherein the first current source further comprises a capacitor coupled in series with the leakage control winding. (Claim 5) 5. The control console of claim 1, wherein the primary winding, the leakage control winding, and the secondary winding are collectively configured to generate a capacitance between the leakage control winding and the secondary winding. (Claim 6) 6. The control console of claim 1, wherein the drive signal is configured to drive an ultrasonic surgical instrument. (Claim 7) 7. The control console of claim 1, wherein the drive signal is configured to drive a radio frequency surgical instrument. (Claim 8) 8. The control console of claim 1, further comprising a second current source configured to cancel out the leakage current, the second current source coupled to the path of the drive signal and to the sensor. (Claim 9) The control console of claim 8 , wherein the second current source is energized by the power supply. (Claim 10) 10. The control console of claim 8 or 9, wherein the second current source is configured to receive the sensed signal and a target value as inputs and to determine a second cancellation current to be injected into the path of the drive signal to cancel out residual leakage current. (Claim 11) 11. The control console of claim 10, wherein the second current source comprises a gain device coupled to the sensor, the gain device configured to determine a difference between the sensed signal and the target value and to determine the second offset current based on the difference. (Claim 12) 12. The control console of claim 11, wherein the second current source further comprises a capacitor coupled to the gain device, the capacitor configured to block a DC component of the second cancellation current. (Claim 13) 13. The control console of claim 8, wherein the first current source and the second current source are configured to collectively reduce leakage current to 10 μA or less. (Claim 14) 14. The control console according to claim 1, wherein the sensor is configured to detect a current of the drive signal and output the current of the drive signal as the detection signal. (Claim 15) 15. The control console of claim 1, wherein the sensor is configured to detect a common mode current of the drive signal and to output the common mode current of the drive signal as the detection signal, the common mode current being related to a leakage current of the drive signal. (Claim 16) 15. The control console of claim 14, wherein the path of the drive signal comprises a high-voltage side conductor and a low-voltage side conductor, and the sensor is further defined as a transformer winding disposed around both the high-voltage side conductor and the low-voltage side conductor, the transformer winding configured to output a common-mode current of the drive signal. (Claim 17) 17. The control console of claim 16, further comprising: a second current source coupled to the path of the drive signal and to the sensor, the second current source configured to receive the common-mode current and a target current as inputs and to determine a second cancellation current to be injected into the path of the drive signal to cancel out residual leakage current, the second current source comprising a gain device configured to determine a difference between the common-mode current and the target current and to determine the second cancellation current based on the difference. (Claim 18) 18. The control console of claim 17, wherein the target current is 0 amps. (Claim 19) 19. The control console of claim 1, wherein the path of the drive signal includes a high-voltage side conductor and a low-voltage side conductor, and the sensor is coupled to the low-voltage side conductor and configured to detect a voltage from the low-voltage side conductor and output the voltage as the detection signal. (Claim 20) 20. The control console of claim 1, wherein the sensor is a capacitor. (Claim 21) 20. The control console of claim 19, further comprising: a second current source coupled to the sensor, the second current source configured to receive the sensed voltage and a target voltage as inputs and to determine a second cancellation current to be injected into the path of the drive signal to cancel out residual leakage current, the second current source comprising a gain device configured to determine a difference between the sensed voltage and the target voltage and to determine the second cancellation current based on the difference. (Claim 22) 22. The control console of claim 21, wherein the second current source is configured to inject the second countervailing current into the low voltage side conductor. (Claim 23) 22. The control console of claim 21, wherein the target voltage is 0 volts. (Claim 24) 24. The control console according to any one of claims 1 to 23, wherein the control console further comprises a fault detection stage coupled to the sensor and configured to receive the sensing signal and to generate a fault detection signal for detection of a fault condition related to leakage current. (Claim 25) 25. The control console of claim 24, wherein the fault detection stage comprises a low pass filter, a rectifier, and a filter configured to modify the sense signal to generate the fault detection signal. (Claim 26) 25. The control console of claim 24, further comprising a controller coupled to the fault detection stage and configured to receive the fault detection signal from the fault detection stage and to determine the fault condition related to leakage current. (Claim 27) 27. A control console according to any one of claims 24 to 26, wherein the fault detection stage is configured to detect the presence of the fault detection signal for a predetermined period of time and to transmit the fault detection signal to a controller once the predetermined period of time has been reached. (Claim 28) 28. The control console of claim 24, wherein the controller is configured to compare the fault detection signal to a target value to determine the fault condition, and to reduce or terminate power to the surgical instrument in response to the determination of the fault condition. (Claim 29) a control console for providing a drive signal to a surgical instrument, a transformer having a primary winding and a secondary winding, the primary winding configured to receive an input signal from a power source and to induce the drive signal on the secondary winding to provide the drive signal to the surgical instrument; a first current source having a leakage control winding coupled to a path of the drive signal, the primary winding configured to induce in the leakage control winding a first cancellation current to be injected into the path of the drive signal to cancel a leakage current of the drive signal; a sensor configured to sense a characteristic of the input signal and to output a sensed signal related to the characteristic of the input signal; a second current source coupled to the path of the drive signal; a variable gain device coupled to the sensor and to the second current source; a selection interface coupled to the second current source and to the variable gain device, the selection interface configured to enable selection of one of a plurality of leakage current adjustment settings and to provide the selected leakage current adjustment setting to the variable gain device; It is equipped with the variable gain device is configured to receive the sense signal and to modify the sense signal based on the selected leakage current adjustment setting; the second current source is configured to generate a second cancellation current based on the modified sense signal from the variable gain device and to inject the second cancellation current into the path of the drive signal to cancel leakage current of the drive signal, a control console. (Claim 30) 30. The control console of claim 29, wherein the second current source comprises a variable gain amplifier. (Claim 31) 30. The control console of claim 29, wherein the sensor is a transformer winding. (Claim 32) 30. The control console of claim 29, wherein the selection interface is a potentiometer. (Claim 33) 33. The control console of claim 32, wherein the potentiometer is a digital potentiometer controlled by software. (Claim 34) 34. A control console according to any one of claims 29 to 33, wherein the leakage current adjustment settings are stored in a look-up table in non-transitory memory. (Claim 35) 35. The control console of any one of claims 29 to 34, wherein the primary winding of the transformer is coupled to a variable power supply. (Claim 36) 36. The control console of claim 35, wherein the variable power supply also energizes the second current source. (Claim 37) a control console for providing a drive signal to a surgical instrument, A variable power supply; a transformer having a primary winding and a secondary winding, the primary winding coupled to the variable power supply and configured to receive an input signal from the variable power supply and to induce a drive signal in the secondary winding to provide the drive signal to the surgical instrument; a current source coupled to a path of the drive signal and coupled to the variable power supply, the variable power supply configured to energize the current source, the current source configured to generate a cancellation current to be injected into the path of the drive signal to cancel leakage current of the drive signal; A control console comprising: (Claim 38) 38. The control console of claim 37, further comprising a sensor coupled to the path of the drive signal, the sensor configured to output a sensed signal to provide feedback related to leakage current. (Claim 39) 39. The control console of claim 38, wherein the current source is coupled to the sensor. (Claim 40) 40. The control console of claim 39, wherein the current source comprises a gain device coupled to the sensor, the gain device configured to receive the sensed signal and a target value as inputs, to determine a difference between the sensed signal and the target value, and to determine the offset current based on the difference. (Claim 41) The control console a sensor configured to sense a characteristic of the input signal and to output a sensed signal related to the characteristic of the input signal; a variable gain device coupled to the sensor and to the current source; a selection interface coupled to the current source and to the variable gain device, the selection interface configured to enable selection of one of a plurality of leakage current adjustment settings and to provide the selected leakage current adjustment setting to the variable gain device; Further provided with the variable gain device is configured to receive the sense signal and to modify the sense signal based on the selected leakage current adjustment setting; 41. The control console of any one of claims 37 to 40, wherein the current source is configured to generate the cancellation current based on the modified sense signal from the variable gain device. (Claim 42) 42. A control console according to any one of claims 37 to 41, wherein the variable power supply is variable within a range defined between 25VDC and 250VDC. (Claim 43) 41. The control console of claim 40, wherein the variable power supply energizes the source to the target value, the variable power supply configured to provide the target value including a DC offset in addition to an AC value. (Claim 44) 1. A method of operating a control console that provides a drive signal to a surgical instrument, the control console comprising: a transformer having a primary winding and a secondary winding, the secondary winding coupled to a path of the drive signal; a first current source having a leakage control winding coupled to the path of the drive signal; and a sensor coupled to the path of the drive signal, the method comprising: receiving an input signal from a power source via the primary winding; inducing the drive signal in the secondary winding by the primary winding; providing the drive signal to the surgical instrument through the secondary winding; inducing a first canceling current in the leakage control winding by the primary winding; injecting the first cancellation current into the path of the drive signal with the first current source; canceling a leakage current of the drive signal with the first cancellation current; outputting, by the sensor, a detection signal to provide feedback related to leakage current; The method comprising: (Claim 45) 1. A method of operating a control console that provides a drive signal to a surgical instrument, the control console comprising: a transformer having a primary winding and a secondary winding; a first current source having a leakage control winding coupled to a path of the drive signal; a sensor; a second current source coupled to the path of the drive signal; a variable gain device coupled to the sensor and to the second current source; and a selection interface coupled to the second current source and to the variable gain device, the method comprising: receiving an input signal from a power source via the primary winding; inducing the drive signal in the secondary winding by the primary winding; providing the drive signal to the surgical instrument through the secondary winding; inducing a first canceling current in the leakage control winding by the primary winding; injecting the first cancellation current into the path of the drive signal with the first current source; detecting a characteristic of the input signal with the sensor; outputting, by the sensor, a sensed signal related to the characteristic of the input signal; enabling selection of one of a plurality of leakage current adjustment settings via the selection interface; providing the selected leakage current adjustment setting to the variable gain device via the selection interface; receiving, by the variable gain device, the sensed signal; modifying, with the variable gain device, the sense signal based on the selected leakage current adjustment setting; generating, by the second current source, a second cancellation current based on the modified sense signal from the variable gain device; injecting, by the second current source, the second cancellation current into the path of the drive signal to cancel leakage current of the drive signal; The method comprising: (Claim 46) 1. A method of operating a control console that provides a drive signal to a surgical instrument, the control console comprising: a variable power supply; a transformer having a primary winding and a secondary winding, the primary winding coupled to the variable power supply; and a current source coupled to a path of the drive signal and coupled to the variable power supply, the method comprising: receiving an input signal from the variable power supply via the primary winding; inducing the drive signal in the secondary winding by the primary winding; providing the drive signal to the surgical instrument through the secondary winding; energizing the current source with the variable power supply; causing the energized current source to generate a cancellation current to be injected into the path of the drive signal to cancel leakage current of the drive signal; The method comprising:

Claims

1. a control console for providing a drive signal to a surgical instrument, A variable power supply; a transformer having a primary winding and a secondary winding, the primary winding connected to the variable power supply to receive an input signal from the variable power supply and induce a drive signal in the secondary winding to provide the drive signal to the surgical instrument; a current source connected to a path of the drive signal and connected to the variable power supply; a sensor that senses a characteristic of the input signal and outputs a sensed signal related to the characteristic of the input signal; a variable gain device connected to the sensor and the current source; a selection interface connected to the current source and the variable gain device, the selection interface enabling selection of one of a plurality of leakage current adjustment settings and providing the selected leakage current adjustment setting to the variable gain device; It is equipped with the variable power supply energizes the current source; the current source generates a cancellation current to be injected into the path of the drive signal to cancel a leakage current of the drive signal; the variable gain device receives the sensed signal and modifies the sensed signal based on the selected leakage current adjustment setting; The current source generates the cancellation current based on the modified sense signal from the variable gain device, a control console.

2. 2. The control console of claim 1, wherein the variable power supply is variable within a range defined by 25 VDC to 250 VDC.

3. 3. The control console of claim 1, further comprising a second current source having a leakage control winding connected to the path of the drive signal, the primary winding inducing a second cancellation current in the leakage control winding to inject the second cancellation current into the path of the drive signal to cancel leakage currents in the drive signal.

4. A control console according to any preceding claim, wherein the current source comprises a variable gain amplifier.

5. A control console according to any preceding claim, wherein the sensor is a transformer winding.

6. A control console according to any one of claims 1 to 5, wherein the selection interface is a potentiometer.

7. 7. The control console of claim 6, wherein the potentiometer is a software controlled digital potentiometer.

8. A control console according to any preceding claim, wherein the leakage current adjustment settings are stored in a look-up table in non-transitory memory.

9. A control console according to any preceding claim, wherein the output of the variable gain device is fed to a power amplifier driven by the variable power supply, the power amplifier outputting a cancellation current.

10. A control console as described in claim 9, wherein the input signal is a DC input signal having a varying potential, and the variable power supply applies the DC input signal to a center tap of a primary winding of the transformer to induce the drive signal, and applies the DC input signal to the power amplifier to energize the current source.

11. A control console as described in any one of claims 1 to 10, wherein the offset current is DC blocked by a capacitor before being injected into the path of the drive signal.

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