Console comprising transformer having leakage control winding and having capacitor

Abstract

A console for an electrically powered surgical tool (310) includes a transformer (250) having a secondary winding (264) on which a tool drive signal is present. The transformer is also internally provided with a matched current source which comprises a leakage control winding (246) and a capacitor. The current supplied by the matched current source at least partially counteracts the possibly present leakage current.

Description

[0001] This application is a divisional application of the invention patent application with application date of May 25, 2017, application number 202110940643.4, and invention name “Control console including a transformer with a leakage control winding and a capacitor”, and the latter is a divisional application of the invention patent application with application date of May 25, 2017, application number 201780047057.9, and invention name “Control console including a transformer with a leakage control winding and a capacitor”. Field of the Invention

[0002] The present invention generally relates to a power console for supplying a drive signal to an electric surgical tool. The power console of the present invention includes a transformer having an internal matching current source. The current source generates a current matched to a parasitic current to minimize leakage current. Background Art

[0003] It can be generally considered that an electric surgical tool system has three basic components. The control component generates a drive signal having the characteristics required for actuating the second component of the system, the power generator. The power generator typically converts the electrical energy of the drive signal into another form of energy. The types of energy converted into electrical energy include mechanical energy, thermal energy (heat) and photon (light) energy. The third component of the tool system is an energy applicator. The energy applicator receives the energy output by the power generator and applies the energy to the target tissue to perform a specific treatment task. Some tool systems are designed to apply electrical energy directed to the target tissue. In this type of system, the power generator is essentially a conductor to which the drive signal is applied to an exposed electrode, through which current is provided to the tissue. These electrodes serve as energy applicators.

[0004] An integral component of many surgical tool systems is the handpiece. At a minimum, the handpiece is a physical component designed to be held by a physician, with an energy applicator extending from the handpiece. Typically, a power generator is contained in the handpiece. A surgical tool system designed in this way is an ultrasonic surgical tool system. The handpiece of the system includes a power generator consisting of one or more drivers. Each driver vibrates in response to the application of an AC signal. The flared portion is tightly mechanically coupled to the driver. The tip used as an energy applicator extends distally from the flared portion. The vibration of the driver causes similar vibrations in the flared portion and even in the tip. The vibrating tip moves against the tissue, causing ablation and removal of the tissue.

[0005] An inherent characteristic shared by many powered surgical tool systems and other powered components is the presence of parasitic capacitance across the components of these systems. Parasitic capacitance is the capacitance that exists across two components that are at unequal voltages. As a result of the presence of this capacitance, a parasitic current can flow through one of the components. For example, when the handpiece includes a power generation unit that applies an AC drive signal, a parasitic current can flow through the metal structural components due to the parasitic capacitance between the handpiece and the metal structure of the power generating components within the handpiece (through which the current flows). This parasitic current contributes to what is known as leakage current. Leakage current is an unwanted current that flows through a system component to which the current is applied for other purposes.

[0006] For safety reasons, the patient to whom the handpiece of an electric surgical tool is applied is considered to be connected to the earth. If a handpiece in which leakage current may exist is applied to a patient, then theoretically the leakage current can flow through the patient to the ground. This current may adversely affect the function of the patient's own organs and tissues. This is why surgical tool systems with handpieces intended to be applied to most patients are generally designed to ensure that the rated leakage current is less than 100 microamperes. Surgical tool systems with handpieces intended to be applied to cardiac tissue typically must be designed to have a rated leakage current of less than 10 microamperes. These requirements are based on the IEC60601 medical design standard. The IEC60601 standard also describes the process of testing electric surgical tools to ensure that the leakage current is below these maximum values.

[0007] There is also a requirement that, for safety reasons, a tool applied to a patient cannot serve as a connection to earth ground. Thus, if a voltage from another source were somehow applied to the patient, the tool would not function as a ground, which could cause current to flow through the patient.

[0008] A number of approaches are employed to reduce the flow of leakage current from an electrically powered surgical handpiece. One approach is to reduce parasitic capacitance to reduce the parasitic current. If the tool is an ultrasonic handpiece, the parasitic capacitance may be reduced by providing electrically insulating impedance disks between the driver and the horn where the mechanical components of the handpiece will be vibrated by the driver. A disadvantage associated with providing these disks is that they inhibit the transfer of vibrations from the driver to the horn and tip. This mechanical damping reduces the efficiency of the handpiece.

[0009] A second method of reducing leakage current is to provide a matching current source. The matching current source applies a current to the low-side conductor associated with the handpiece power generation unit. Ideally, this matching current is opposite in direction and equal in magnitude to the parasitic current present on the high-side conductor. The matching current cancels the parasitic current. Ideally, the cancellation of the parasitic current eliminates the contribution of the parasitic current to the leakage current. The leakage current is primarily composed of parasitic currents. Therefore, the elimination of parasitic currents substantially eliminates the flow of leakage current from the handpiece through the patient.

[0010] The matching current source is formed by two components. The first of these components is a supplementary winding integral with the transformer, which is part of the control assembly. The second of these components is a capacitor distinct from the transformer.

[0011] Components of the type described above work fairly well for providing a matched current source that provides current to counteract the leakage current flowing through the high side conductor. However, current practice is to employ a Y-type capacitor as the second component of the current source. The maximum voltage that can be allowed to be developed across the Y-type capacitor is typically 250VAC or less. The voltage present across the conductors of an ultrasound handpiece may typically exceed 1000VAC. Therefore, it has proven difficult to demonstrate that a surgical tool system having an ultrasound driver with a matched current source is able to reduce the magnitude of the leakage current.

[0012] Another difficulty associated with providing a matched current source for reducing leakage current for an electric surgical tool system is that it can be difficult to regulate the current flowing out of the current source. This can cause the tool system to enter a state where the parasitic current and the matching current are not substantially equal. If the handpiece enters this state, there is a potential for leakage current above an allowable level to flow through the patient. Summary of the invention

[0013] The present invention relates to a novel and useful power console for a surgical tool system. The power console is used as a system component for providing a drive signal to a power generation unit of the system. More specifically, the power console of the surgical tool system of the present invention includes a transformer with an independent matching current source.

[0014] The power supply console of the present invention includes a transformer, which is used as a console component to output a drive signal, which is applied to the power generation unit of the system head. The input signal is applied to the primary winding of the transformer. The signal present on the secondary winding of the transformer is the drive signal.

[0015] The transformer also includes a matching current source. The matching current source generates a current that is equal in magnitude and opposite in direction to the parasitic current existing between the high-side conductors, and the drive signal is applied to the power generation unit of the tool system on the high-side conductors. The matching current source includes a winding and a capacitor. The winding is called a leakage control winding. One end of the leakage control winding is grounded. The capacitor is connected in series between the free end of the leakage control winding and the low-side conductor.

[0016] Typically, the capacitor matching the current source comprises at least one layer of conductive foil wrapped around a winding of a transformer. The conductive sheath serves as one plate of the capacitor.

[0017] In some forms of the invention, the transformer includes a second conductive sheath disposed around the windings. In some types of the invention, the second sheath serves as a second plate of the capacitor. In some types of this version of the invention, the second conductive sheath serves as a shield around the one or more windings wrapped by the conductive material layer.

[0018] In some forms of the invention, a portion of one of these windings also serves as a second plate of a capacitor matching the current source. In some types of this form of the invention, at least a portion of the secondary winding serves as a second plate of the capacitor. In other types of this form of the invention, the leakage current winding serves as a second plate of the capacitor.

[0019] In some forms of the invention, the leakage current winding includes a plurality of sub-windings. One or more switches connect these sub-windings together. This feature of the invention allows the voltage, and even the current, produced by the matching current source to be selectively set for a given voltage on the primary winding. This allows the current level supplied by the matching current source to be selectively set. This provides the ability to set the current level provided by the matching current source with increased accuracy during the manufacture of the console integrated with the transformer, so that the current level is substantially equal to the parasitic current. In some structures of the invention, this ability to set the current level provided by the matching current source also makes it possible to use a single console to provide drive signals to heads that require drive signals of significantly different frequencies.

[0020] In many forms of the invention, the transformer also includes a sensing winding. The signal on the sensing winding is used by other components of the system as a signal representing the voltage of the drive signal. In some forms of the invention where there is a sensing winding, the sensing winding is connected to the leakage control winding.

[0021] Some of the electric surgical tool systems of the present invention are ultrasonic tool systems. The ultrasonic tool system includes one or more drivers. The drivers are transducers that serve as the power generating units of the system. When an AC drive signal is applied to these drivers, they contract and expand periodically. The tips are mechanically connected to these drivers. The expansion / contraction of the drivers causes a vibratory motion of the tips. The tips are applied to the patient's tissue so that the vibration action produces the appropriate therapeutic effect on the tissue. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention to which this application is directed is pointed out in detail in the claims. The above and other features and advantages of the invention will be understood from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0023] Figure 1 The basic components of a powered surgical tool system incorporating features of the present invention are depicted;

[0024] Figure 2 It is a diagrammatic representation of the mechanical parts and the machine head of the tool of the system;

[0025] Figure 3 is a block diagram of the basic electrical components of both the console and the handpiece of the system;

[0026] Figure 4 It is a schematic diagram of the transformer inside the console, the handpiece, and the patient to which the handpiece is applied.

[0027] Figure 5 is a cross-sectional view of a first transformer of the present invention;

[0028] Figure 6 yes Figure 5 Schematic diagram of the transformer;

[0029] Figure 7 is a cross-sectional view of a second transformer of the present invention;

[0030] Figure 8 yes Figure 7 Schematic diagram of the transformer;

[0031] Fig. 9 is a cross-sectional view of a third transformer of the present invention;

[0032] Fig.10 yes Fig. 9 Schematic diagram of the transformer;

[0033] Fig.11 is a schematic diagram of a fourth transformer of the present invention. DETAILED DESCRIPTION

[0034] Reference now Figure 1 and 2 The electric surgical tool system 40 of the present invention is generally described. The system 40 includes a handpiece 310. The handpiece 310 is an ultrasonic surgical tool. Therefore, in this form of the invention, the system 40 can be described as an ultrasonic surgical tool system. The handpiece 310 includes a body or shell 312 that forms the proximal end of the handpiece. ("Proximal" should be understood to mean toward the physician holding the handpiece and away from the area where the handpiece is applied. "Distal" should be understood to mean away from the physician and toward the area where the handpiece is applied.) The body 312 is the part of the handpiece 310 that is actually held by the physician.

[0035] One or more vibration piezoelectric drivers 324 (four are shown) are disposed within the housing 312. Figure 2In the embodiment of the present invention, the handpiece housing 312 is not visible, so the internal components of the handpiece 310 are exposed. Each driver 324 is formed of a material that undergoes a transient expansion or contraction when an AC voltage is applied to the driver. These expansions / contractions are located on the longitudinal axis of the driver 324, which extends between the proximal and distal faces of the driver. A pair of leads 328, at Figure 2 Only two leads are seen extending away from each driver 324. Leads 328 are attached to the above-mentioned opposite proximal and distal faces of the driver 324. Many, but not all, heads 310 include a disc-shaped piezoelectric driver 324. These drivers 324 are arranged end to end in a stack. Leads 328 are the components of the system 40 that apply voltage to the driver 324 in the form of a drive signal. Figure 2 In the embodiment, the drivers 324 are shown as being spaced apart from each other. This is for the convenience of illustrating these components. In fact, the drivers 324 are closely abutted.

[0036] The driver 324 is understood to convert the electrical energy applied to the driver into mechanical power. Therefore, the driver 324 functions together as a (mechanical) power generator of the system 40.

[0037] The post 330 extends longitudinally through the driver 324. The post 330 extends through the driver 324 along the colinear longitudinal axis of each driver. The hole located inside the driver 324 through which the post 330 extends is not visible in the figure. The post 330 protrudes outwardly from the driver 324 located at the most side and the driver 324 located at the most side.

[0038] The proximal end mass 320 is disposed adjacent to the proximally directed face of the proximal-most driver 324. The exposed proximal end portion of the post 330 is fixedly attached to the mass 320. If the post 330 has threads, the mass 320 may be a nut.

[0039] The flared portion 334 extends forward from the distally directed face of the most distal driver 324. Although not shown, an insulating disk may be located between the distal driver 324 and the flared portion 334. The flared portion 334 has a proximal end base having a diameter substantially equal to the diameter of the driver 324. Extending distally and forwardly from the driver 324, the diameter of the flared portion 334 decreases. The exposed distal end portion of the post 330 is attached to the flared portion 334. If the post 330 is threaded, the flared portion base may be formed with a threaded hole (not identified) for receiving the post 330. The nose 310 is configured such that the stack of drivers 324 is compressed between the proximal end mass 320 and the flared portion 334.

[0040] The tip 340 extends forward from the distal end of the flare 334. A coupling assembly, represented by cylinder 336, extends forward from the flare 334. The coupling assembly removably holds the tip 340 to the flare 334 and, therefore, to the remainder of the handpiece 310. The structure of the coupling assembly is not part of the present invention. The tip 340 includes an elongated rod 342. The rod 342 is that portion of the tip that is attached to the flare 334 by the coupling assembly. The rod 342 extends forward of the handpiece housing 312. The tip 340 is formed with a head 344 at the distal end of the rod 342. Some tip heads 344 have a smooth surface. Some heads 344 are formed with teeth 346. The geometry of the head 344 is not part of the present invention. The tip head 344 is that portion of the handpiece 310 that is applied to the surgical site of the patient. At Figure 1 , the tip head 344 is shown applied to a portion of tissue 380.

[0041] Some tip heads 344 are provided with teeth designed to be applied directly to hard tissue, such as bone. When this type of tip is reciprocated, the teeth cut tissue in the same manner as a conventional saw blade cuts tissue.

[0042] Typically, the cannula 350 is disposed on the tip shaft 342. Typically, the cannula 350 extends from near the location where the shaft 342 is attached to the trumpet 334 to a location approximately 0.5 cm proximal to the head 344. In general, the handpiece 310, the tip 340 and the cannula 350 are configured such that the cannula defines a fluid flow conduit extending between the outer surface of the tip and the surrounding inner surface of the cannula. The cannula 350 has a joint 352 adjacent to the proximal end of the cannula extending to this conduit. The conduit opens at the distal end of the cannula 350. When the handpiece 310 is used, the irrigation solution starts from the cannula joint, flows along the cannula and is discharged adjacent to the tip head 344. In some forms of this system, the fluid is used as a medium through which the mechanical vibrations of the tip head are transmitted to the tissue. Due to the vibration of the head 344, the irrigation solution also serves as a heat sink for the heat energy generated by the tip head.

[0043] Although not seen, the handpiece post 330, flared portion 334 and tip 340 are typically formed with conduits. These conduits together define a fluid flow path from the tip head 344 to the proximal end of the handpiece 310. When the handpiece 310 is in operation, suction is applied through these conduits. Irrigation fluid is suctioned away from the area to which the tip is applied through the cannula 350. Entrained in this irrigation fluid is debris generated by the actuation of the tip 340. This suction also draws these tissues toward the tip head 344. Shortening the distance between the tip head and the tissue improves the transmission of mechanical vibrations from the tip head to the tissue.

[0044] The handpiece 310 of the system 40 capable of applying suction is sometimes referred to as an aspirator or ultrasonic aspirator.

[0045] The nose 310 also includes Figure 3 Memory 338 is seen in the form of a block in the figure. Memory 338 contains data describing the characteristics of the head. Memory 338 can be in the form of an EPROM, EEPROM or RFID tag. The structure of the memory is not part of the present invention. Memory 338 contains data identifying the head 310. Memory 338 also contains data describing the characteristics of the drive signal that can be applied to the head driver 324. Most heads 310 of the present invention include a memory that, in addition to containing data that can be read, can also store data that is written to the memory after the head 310 is manufactured. Auxiliary components not shown are mounted on the head to facilitate reading data from and writing data to the memory. These components include one or more of the following: conductors; exposed contacts / styluses; coils / antennas; or isolation circuits.

[0046] Reference now Figure 1 and 3 The console 50 described is also part of the system 40 of the present invention. The console 50 supplies the drive signal through the cable 304 connected to the handpiece 310. In the form of the present invention where the handpiece 310 is an ultrasound handpiece, it is common, but not necessary, to assemble the cable 304 and the handpiece 310 into a single unit. The drive signal is applied to the driver 324. At any given moment, the same drive signal is applied to each driver 324. The application of the drive signal causes the driver to expand and contract simultaneously and periodically. The length of the driver 324 stack is generally between 1 and 5 cm. The distance and amplitude of a single expansion / contraction cycle of the driver can be between 1 and 10 microns. The flared portion 334 amplifies this movement. Therefore, when moving from a fully retracted position to a fully extended position, the distal end of the flared portion 334, and even the tip head 344, generally moves a maximum of 1000 microns, typically 500 microns or less. Some tips 340 are also designed so that the longitudinal extension / contraction of the tip rod 342 also causes a rotational movement in the head 344. This rotational motion is sometimes referred to as torsional motion.When the handpiece 310 is actuated to cause cyclical motion of the tip, the head 344 is considered to be vibrating.

[0047] Generally in Figure 3The components inside the console 50 as seen in FIG. 4 include a power supply 52. ​​The power supply 52 outputs a DC voltage of a set level. The voltage is typically between 25 and 250 VDC. The voltage of the signal output from the power supply 52 is set based on the POWER_SUPPLY_CONTROL (PS_CNTRL) signal applied to the power supply. The signal output by the power supply 52 is applied to the center tap of the primary winding 252 of the transformer 250. The opposite ends of the primary winding 252 of the transformer are connected to a linear amplifier 58. The amplifier 58 applies an AC signal of varying potential and frequency to both ends of the primary winding 252 of the transformer. The BASE signal applied to the amplifier 58 regulates the frequency and potential of the signal output by the amplifier 58 as a control signal. In a form of the present invention in which the system 40 includes an ultrasound handpiece 310, the AC signal generated on the primary winding has a frequency between 10 kHz and 100 kHz. The peak-to-peak voltage of the signal is at least 200 volts, more preferably at least 300 volts.

[0048] The structure of power supply 52 and linear amplifier 58 is not part of the present invention. Further understanding of these subcomponents can be found in PCT Patent Application No. PCT / US2016 / 031651, the contents of which are included in WO 2016 / 183084A1 / US Patent Publication No. _, both of which are expressly incorporated herein by reference.

[0049] The AC signal generated on the primary winding 252 of the transformer 250 induces an AC signal on the secondary winding 264 of the transformer 250. This signal on the secondary winding of the transformer 250 is the drive signal applied to the handpiece driver 324 via the cable 304. In a form of the invention, the drive signal is used to actuate the ultrasonic driver, and the drive signal typically has a voltage of at least 500VAC and typically at least 1000VAC.

[0050] Transformer 250 includes a sense winding 256. Sometimes, sense winding 256 is referred to as a tickle coil. The voltage of the signal present on sense winding 256 is applied to voltage measurement circuit 66. Based on the signal on sense winding 256, circuit 66 generates a signal representing the magnitude and phase of the potential of the drive signal on driver 324. Coil 86, also provided in console 50, is provided in close proximity to one of the conductors extending from transformer secondary winding 264. The signal on coil 86 is applied to current measurement circuit 68. Circuit 68 generates a signal representing the current i S A signal of the magnitude and phase (of the current of the drive signal supplied to the head driver 324).

[0051] Signals representing the voltage and current of the drive signal applied to the handpiece 310 are applied to a processor 80 also inside the console 50. The console 50 also includes a memory reader 78. The memory reader 78 is capable of reading data in the handpiece memory 338. The structure of the memory reader 78 supplements the handpiece memory 338. Therefore, the memory reader can be: a component capable of reading data in an EPROM or EEPROM or a component capable of interrogating an RFID tag and reading data from an RFID tag. In the following form of the invention: in which the data read from the memory 338 is read on the conductor on which the drive signal is supplied to the handpiece 310, the memory reader 78 may include an isolation circuit. The data read by the reader 78 is applied to the processor 80.

[0052] Connected to the console 50 is an on / off switch. Figure 1 and 3 , the on / off switch is represented by a foot pedal 54. The state of the pedal 54 is monitored by the processor 80. The on / off switch is a user-actuated control member that adjusts the on / off state of the system 40. Figure 1 In the embodiment of the present invention, the foot pedal 54 is shown as being part of a foot pedal assembly that includes multiple pedals. The additional pedals can be used to control devices such as irrigation pumps, suction pumps, or lights. These auxiliary devices are not part of the present invention.

[0053] The console 50 is shown with a slide switch 56. As with the foot pedal 54, the state of the switch 56 is monitored by the processor 80. The switch 56 is set by the physician to control the magnitude of the amplitude of the vibration of the tip head 344. The foot pedal 54 and switch 56 should be understood as a general representation of inputting on / off and amplitude setting commands to the system 40. In some configurations of the present system, a single control member can perform both functions. Thus, the system 40 can be configured so that upon initial depression of the control lever or foot pedal, the system causes the tip head to undergo a vibration cycle with a relatively small amplitude. With continued depression of the control lever or foot pedal, the console resets the drive signal applied to the handpiece so that the tip head 344 undergoes a vibration cycle with a larger amplitude.

[0054] The display 82 is built into the console 50. The images on the display 82 are displayed as generated by the processor 80. The information depicted on the display 82 includes information identifying the handpiece and possible tip and information describing the characteristics of the operating rate of the system. The display 82 can be a touch screen display. In these forms of the invention, commands can be input into the processor 80 by pressing the image of a button presented on the display 82. The interface components between the display 82 and the processor 80 are not shown, which facilitate the display of images on the display and the input of commands into the processor.

[0055] The processor 80 adjusts the drive signal output from the console 50. The inputs of the physician control are the state of the on / off pedal 54 and the state of the slide switch 56, and the processor 80 sets the drive signal based on the inputs of the physician control. The commands input through the display 82 can also be used to control the setting of the drive signal. The characteristics of the drive signal are also set based on the data read from the head memory 338. The characteristics of the drive signal are also used by the console as feedback signals, which further contribute to the setting of the drive signal. Based on these multiple inputs, the processor 80 outputs signals that control the drive signal. These signals are the POWER_SUPPLY_CONTROL signal applied to the power supply 52 and the BASE signal applied to the amplifier 58.

[0056] By reference Figure 4 Gain an understanding of the theory of operation of the transformer 250 of the present invention. Figure 4 2 is a schematic diagram of the active electrical components of transformer 250 and the components to which the drive signals generated by the components are applied. The transformer is thus shown to have a core 270. On the left side of the core 270, the transformer 250 is shown to include a primary winding 252. Figure 3 It will be appreciated that opposite ends of the primary winding 252 are connected to the linear amplifier 58. The voltage output by the power supply 52 is applied to the center tap of the primary winding 252. To reduce the complexity of the drawing, Figure 4 The sensing winding 256 is not shown.

[0057] The secondary winding 264 is shown on the right side of the core 270, directly opposite the primary winding 252. Figure 4 In the embodiment, the driver 324 is connected to the capacitor C by their electrical equivalent. D Resistor R HP As shown in the figure with capacitor C D Resistor R HP 310 and the tip 340. The impedance may actually have a resistive component, a capacitive component, and an inductive component. Conductor 278 represents the high side conductor inside the console 50, cable 304, and handpiece 310 that connects the secondary winding 264 to the driver 324. Conductor 284 is the low side conductor, the return conductor, between the driver 324 and the secondary winding 264. The current flowing into the secondary winding 264 and from the secondary winding 264 to the driver is the current i HP Current i HP is a function of the voltage of the drive signal and the impedance of the handpiece, capacitor C D With impedance R Hp The impedance of the mechanically equivalent parallel circuit.

[0058] exist Figure 4Also seen in Figure 6 is a circuit that is considered to represent the human body for leakage current analysis and testing. This circuit is based on the standards contained in IEC 60601. The circuit consists of a parallel circuit with two branches. The first branch of the circuit is a resistor R T1 The second branch of the model is with capacitor C T The second resistor R in parallel T2 In this model, a surgical tool is applied to one end of the circuit. The opposite end of the circuit is considered to be grounded. To prevent damage to the tissue, current flows from the surgical instrument to the tissue, and the leakage current i through the circuit is L should be zero. Since the current i HP is the result of the drive signal, so all of this current flows from the high-side conductor 278 through the driver 324 and back through the low-side conductor. Therefore, the current i HP Leakage current i L No contribution.

[0059] The circuit that applies the drive signal from the secondary winding 264 to the driver 324 also has parasitic capacitances. These capacitances are represented by the series connection of capacitors C PH and C PL . Connected to capacitor C PH and C PL The conductors and ground are shown as dashed components because they do not actually exist in the circuit. Capacitor C PH and C PL The connection point of capacitor C is grounded. PH , i.e., the capacitor connected to the high side conductor 278, represents the parasitic capacitance between the high side conductor and ground. Capacitor C PL , i.e., the capacitor connected to the low side conductor 284, represents the parasitic capacitance between the low side conductor 284 and ground.

[0060] The presence of these parasitic capacitances causes parasitic currents to flow through the conductive components of the system 40. Specifically, through the capacitor C PH The parasitic current is the parasitic current i PH Through capacitor C PL The parasitic capacitance leads to the parasitic current i PL If parasitic currents flow through the low side conductor 284, then these currents will form a component of the leakage current iL. Again, in order to prevent damage to tissue, it should be understood that the current iL should be zero or at least as close to zero as possible.

[0061] In order to prevent parasitic current from flowing through the low-side conductor 284, the transformer 250 has a variable matching current source inside. The current source generates a matching current iM, which is applied to the low-side conductor 284 and is proportional to the current i PH The magnitude is equal and the direction is opposite, the current i PH is due to the high-side capacitance CPH The matching current i M The application of has two effects on the parasitic current flowing on conductor 284 to tissue 380. First, since the matching current iM is equal to or substantially equal to the parasitic current i PH , so the parasitic current i PH The contribution to the presence of current iL applied to the tissue is reduced, if not substantially eliminated. For the purposes of the present invention, the matching current iM is considered to be substantially equal to the parasitic current iL if the matching current cancels the parasitic current to the extent necessary to keep the leakage current below the standard for the system integrated with the transformer 250. PH When transformer 250 is included in console 50 and console 50 is the part of surgical tool system 40 that must meet the IEC 60601 body floating standard, if the matching current is within the parasitic current i PH If the matching current is within 100 microamperes of the parasitic current i , the matching current is considered to be substantially equal to the parasitic current. When transformer 250 is included in console 50 and console 50 is the part of surgical tool system 40 that must meet the IEC60601 cardiac floating standard, if the matching current is within 100 microamperes of the parasitic current i PH If the matching current is within the range of 10 microamperes, it is considered that the matching current is basically equal to the parasitic current.

[0062] Matching current i M The presence of the low-side parasitic current i PL Specifically, since the matching current iM is substantially equal to the high-side parasitic current i PH , so the parasitic capacitor C PL The voltage on the 380 is essentially zero. Due to this voltage balance, there is almost no low-side parasitic current i that contributes to the leakage current iL through the tissue 380. PL , if it exists, it is very rare.

[0063] The matching current source consists of two parts, namely, leakage control winding 246 and capacitor 248, both of which are components of transformer 250. Winding 246 is called a leakage control winding because the parasitic currents are largely, if not entirely, composed of leakage current i L One end of the leakage control winding 246 is grounded. A capacitor 248 is connected in series between the free end of the leakage control winding 246 and the low-side conductor 284. The voltage on the winding 246 varies with the voltage on the primary winding 252. Therefore, the matching current source formed by the winding 246 and the capacitor 248 can be considered as a variable voltage source.

[0064] exist Figure 4The base of the console is shown as ground. This connection is made through capacitor C g . Capacitor C g Represents the parasitic capacitance between the console and ground.

[0065] Figure 5 2 shows the structure of a basic transformer 250 of the present invention. The transformer 250 is formed of an E-shaped core 270 formed of ferrite. The core 270 is formed to have a base 272. Three parallel legs extend outwardly from the base 272. A first leg, a center leg 274, extends outwardly from the center of the base 272. The transformer 250 should be understood to be centered around a longitudinal axis ( Figure 5 The outer legs 275 extend outwardly from opposite ends of the base, one of which is shown. The windings 246, 252, 256 and 264 are wound around the center leg 274 and are contained within the perimeter of a circle defined by the opposing inner surfaces of the outer legs 275.

[0066] The transformer 250 is constructed so that the winding closest to the core center leg 274 is the primary winding 252. In the illustrated form of the invention, the primary winding 252 is shown as having two layers of turns. The layers of turns are separated by a dielectric insulating wrap 276. As described below, the transformer 250 includes a plurality of insulating wraps 276. The wraps 276 are formed by sheets of polyethylene terephthalate resin. One such resin is sold by Dupont Teijin Films under the trademark Mylar. The thickness of the wrap is at least 0.005 mm, and the thickness is usually at least 0.008 mm. The wraps 276 between the layers of turns forming the primary winding 252 are shown as not extending to the base 272 of the core 270. This indicates that the layers of turns forming the primary winding 252 are connected together. The insulating layer 276 disposed on the outer layer of the primary winding 256 is shown as extending over the entire length of the space defined by the core in which these windings are arranged. This means that the primary winding is isolated from the next winding adjacent on the outside.

[0067] The sensing winding 256 is the winding arranged immediately around the primary winding 252. Of any of these windings, the sensing winding 256 has the fewest turns. This is why in Figure 5 , 7 and 9, the sensing winding 252 is shown as comprising a single layer of turns, which comprises relatively few individual turns. In many forms of the invention, the relative orientation of the turns of the winding must be properly set to ensure that the transformer 250 operates properly. Figure 5 The transformer 250 is configured such that the turns of the sensing winding 256 are in the same direction as the turns of the primary winding 252 .

[0068] An insulating layer 276 extends over the sensing winding 256 .

[0069] The leakage control winding 246 is a winding disposed on the sensing winding 256. In many forms of the invention, the leakage control winding 246 has more turns of wire than the sensing winding 256 and fewer turns of wire than the secondary winding 252. The turns of wire forming the leakage control winding are wound around the core center leg 274 in the opposite direction to the turns of wire forming the primary winding 252. An insulating layer 276 extends over the leakage control winding 246.

[0070] An inner conductive sheath 280 extends around an insulating layer 276 disposed on the leakage control winding 246. The sheath 280 is formed of a conductive material such as copper and has a thickness of at least about 0.002 mm and typically at least 0.003 mm. The sheath 280 and the conductive sheaths 288 and 290 described below are non-shorting. This means that the opposite ends of the sheath should not be connected together. The insulating layer 276 is disposed on the conductive sheath 280.

[0071] The secondary winding 264 is a winding disposed on an insulating layer 276 disposed on an inner conductive sheath 280. This secondary winding generally has the most individual wire turns and the most turns of the windings of the transformer 250. Figure 5 , 7 and 9, this is symbolically illustrated by a secondary winding 264 having four layers of turns. The transformer 250 is formed so that the turns of the secondary winding are wound around the core center leg 274 in the opposite direction to the direction in which the turns of wire forming the primary winding 252 are wound. An insulating layer 276 (one of which is identified) that does not extend the entire length of the space (within the core in which these windings are arranged) is shown interleaved with the turns of the secondary winding 264.

[0072] The console 50 is configured so that the wire terminals forming the ends of the innermost turns of the secondary winding are the terminals of the secondary winding connected to the low side conductor 284. The secondary winding 264 of the transformer 250 is wound around the core center leg 274 in the opposite direction to the direction in which the primary winding 252 is wound.

[0073] An insulating layer 276 is shown disposed over the entire length of the outermost turns of the secondary winding 264 .

[0074] The second conductive sheath, sheath 290, is disposed on the insulating layer 276 disposed on the secondary winding 264. An insulating layer 276 is disposed on the second conductive sheath 290.

[0075] By reference Figure 6 Understand the electrical connections between the windings of transformer 250. Figure 6 In and compare Figure 8 and 10, the primary winding 252 is shown as a bifilar winding as it is actually constructed. One end of each bifilar winding is connected to the variable power supply 52. ​​The opposite end of each bifilar winding is connected to the linear amplifier 58, schematically represented as two current sinks.

[0076] One end of the sensing winding 256 is connected to one end of the leakage control winding 246. The two common winding ends are grounded. The free end of the sensing winding 256 is the end of the winding attached to the voltage measurement circuit 66. The free end leakage control winding 246 (the high side of the winding 246) is connected to the inner conductive sheath 280.

[0077] The outer conductive sheath 290 is connected to the end of the secondary winding 264 that is connected to the low side conductor 264. The outer conductive sheath 290 thus acts as an electromagnetic shield around the outside of the transformer winding.

[0078] exist Figure 5 , 7 and 9, the low side conductor 284 is shown connected to the shield 306. The shield 306 is internal to the cable 304. The high side conductor 278 is shown extending through the shield 306.

[0079] When the system 40 of the present invention is actuated, the console 50 causes an AC voltage to be generated across the primary winding 252. The electromagnetic field generated by this voltage induces voltages in the other windings 246, 256, and 264. The voltage induced in the secondary winding 264 is applied as a drive signal to the handpiece driver 324. The voltage generated across the sense winding 256 is applied to the voltage measurement circuit 66 as a measure of the drive signal voltage.

[0080] The voltage generated across the leakage control winding 246 is applied to an inner conductive sheath 280. The sheath is within 2 mm, and more preferably within 1 mm, of the adjacent inner sheaths of the wire turns forming the secondary winding 246. The inner conductive sheath 280 is separated from the adjacent turns of the secondary winding 264 by an insulating layer 276 located between the wire sheaths. Thus, the inner conductive sheath 280, the adjacent sheaths of the turns of the secondary winding, and the insulating layer 276 between the sheaths act as a capacitor 248 for the matching current source of the system 40. Ideally, the components forming the present system are constructed so that the current generated by the current source is equal to the current i that exists due to the high-side parasitic capacitance. PH equal and opposite. The leakage current i PH The cancellation reduces, if not eliminates, the leakage current i L Flow from this system to within the organization.

[0081] Another feature of the transformer 250 of the present invention is that the voltage on the capacitor 248 may exceed 500 volts, more preferably at least 1000 volts, without causing breakdown of the capacitor or the transformer itself. This means that the transformer 250 can output a drive signal of at least 500 volts, more preferably at least 1000 volts, on the secondary winding 264. Drive signals with these voltages are necessary to power the power generation unit of certain powered surgical tools, such as the ultrasound handpiece 310 of the system 40.

[0082] Figure 7 The structure of an alternative transformer 250a is shown, which may be incorporated into the console 50 of the system 40 of the present invention. To minimize redundancy, the identification numbers associated with the portions of the core, windings and insulation associated with the alternative transformer 250a and the alternative transformers 250b and 250c described below are the same, where these components are the same as those of the transformer 250. Furthermore, to minimize redundancy and drawing complexity, the Figure 7 and 9 The insulating layer 276 between the layers of the primary winding and the layers of the secondary winding is not identified.

[0083] As in the first embodiment of the invention, transformer 250a is configured so that primary winding 252 is wound closest to center leg 274 of core 270. Insulation layer 276 is disposed on the outer layer of the primary winding. Inner conductive sheath 280 is disposed on insulation layer 276 surrounding the primary winding.

[0084] The inner conductive sheath 280 is surrounded by an insulating layer 276. The sensing winding 256 is wound around the insulating layer 276 that is wound around the inner conductive sheath 280. The turns of wire forming the sensing winding 256 are wound in the same direction as the turns of wire forming the primary winding 252.

[0085] The secondary winding 264 is wound on an insulating layer 276 disposed on the sensing winding 256. The transformer 250a is configured so that the turns of wire forming the secondary winding 264 are wound in the opposite direction to the turns of wire forming the primary winding. The insulating layer 276 is disposed on the outer layer of the turns forming the secondary winding.

[0086] The outer conductive sheath 290 is disposed on the insulating layer 276 disposed on the secondary winding 276. The insulating layer 276 is disposed on the outer conductive sheath 290.

[0087] The leakage control winding 246 is disposed on an insulating layer surrounding an outer conductive sheath 290. The transformer 250a is formed such that the turns of the leakage control winding 246 are wound in a direction opposite to the direction in which the turns of the primary winding 252 are wound. An insulating layer 276 is wound around the leakage control winding 246 to form an outer skin of a winding subassembly integral with the transformer 250a.

[0088] like Figure 8 As shown, transformer 250a is constructed so that the inner conductive sheath 280 is connected to the high side terminal of the leakage control winding 246. The low side of the leakage control winding 246 is grounded. Also grounded is the low side of the sensing winding 256. The high side of the sensing winding is connected to the voltage measurement circuit 66.

[0089] The outer conductive sheath 290 is connected to the low side of the secondary winding 264. The low side of the secondary winding 264 is also connected to the shield 306 inside the cable 304.

[0090] The transformer 250a is constructed so that the inner conductive sheath 280 serves as one plate of the capacitor 248. The second plate of the capacitor 248 is the innermost turn layer of the secondary winding 264. The dielectric layer of the capacitor 248 consists of an insulating layer disposed around opposite sides of the sensing winding 256. In this form of the invention, the sensing winding 256 is disposed between the two parts of the transformer 250a that form the capacitor 248. The voltage across the sensing winding 256 is relatively low, typically 5% or less of the voltage across the secondary winding 264. As a result, the electric field generated around the sensing winding 256 is also relatively low. Therefore, the presence of the sensing winding 256 between the two parts of the transformer 250a that form the capacitor 248 does not significantly affect the function of the capacitor 248. This means that the capacitor 248 in combination with the leakage control winding 246 can produce a voltage that is proportional to the parasitic current i PH The currents are substantially matched even though there is a sense winding 256 between the plates of the capacitor.

[0091] The outer conductive sheath 290 serves as a shield around the windings 252 , 256 , and 258 disposed within the sheath 290 .

[0092] This form of transformer 250a operates in the same general manner as the first transformer 250. As an AC signal is applied to the primary winding 252, a drive signal is generated on the secondary winding 264. A voltage is also generated on the leakage control winding 246. This voltage to the low side conductor 284, when applied through the capacitor 248, causes a current to exist on the low side conductor that is equal to and opposite to the parasitic current generated between the high side conductor and ground. This matching current reduces, if not eliminates, the extent to which the parasitic current contributes to the leakage current applied to the tissue to which the handpiece is applied.

[0093] Another feature of transformer 250a is that the leakage control winding 246 is the outermost winding of the transformer. This means that the transformer can be placed in a test fixture after all other windings are in place. By applying a voltage to the primary winding and measuring the current through the test fixture and the voltage across it, it can be determined how many turns of wire should be used to build the leakage control winding to ensure that the current produced at the matching current source matches the high-side leakage current as closely as possible.

[0094] Now first refer to Fig. 9 1 and 2. The second alternative transformer 250b of the present invention is described below. The transformer 250b is constructed such that, like the transformer 250, the primary winding 252 is the winding closest to the core center leg 272. An insulating layer 276 is disposed around the primary winding 252. A sensing winding 256 is wound around the insulating layer 276 that wraps around the primary winding 252. The sensing winding 256 is wound in the same direction that the primary winding 252 is wound. The insulating layer 276 is wrapped around the sensing winding 256.

[0095] The inner conductive sheath 280 is disposed on the insulating layer 276 disposed around the sensing winding 256. The insulating layer 276 is disposed around the sensing winding 256. The secondary winding 264 is disposed on the insulating layer 276 disposed on the sensing winding. The transformer 250b is configured so that the secondary winding 264 is wound in the same direction as the primary winding 252. The insulating layer 276 is disposed on the secondary winding 264.

[0096] The middle conductive sheath 288 is disposed on the insulating layer 276 wrapped on the secondary winding 264. The insulating layer 276 is disposed on the middle conductive sheath 288. The outer conductive sheath 290 is disposed on the insulating layer 276 disposed on the middle conductive sheath 288. The insulating layer 276 is disposed on the outer conductive sheath 290.

[0097] The leakage control winding 246 is disposed on an insulating layer surrounding the outer conductive sheath 290. The leakage control winding 246 is wound around the core center leg in the same direction as the primary winding 252 is wound. An insulating layer 276 is wrapped around the leakage control winding 246 to form an outer skin of a winding subassembly integral with the transformer 250b.

[0098] As reference Fig.10As shown, transformer 250b is constructed such that both the inner conductive sheath 280 and the middle conductive sheath 288 are connected to the low side of the transformer secondary winding 264. Thus, the sheaths 280 and 288 together form one plate of capacitor 248. The outer conductive sheath 290 is connected to the high side of the leakage control winding 246. The outer conductive sheath 290 thus forms the second plate of capacitor 248 in transformer 250b. The insulating layer 276 between the conductive sheaths 288 and 290 serves as part of the dielectric layer of capacitor 248.

[0099] Transformer 250b is constructed so that both plates of capacitor 248 are formed by conductive layers. One of the plates, the plate connected to secondary winding 264, is actually formed by two conductive layers, layers 280 and 288. Therefore, capacitor 248 of transformer 250b has a higher capacitance than capacitor 248 of transformers 250 and 252a. This makes it possible to reduce the size of the leakage control winding while still providing a circuit that produces substantially equal parasitic current i PH The current is matched to the current source.

[0100] Fig.11 2 is a schematic block diagram of a third alternative transformer, transformer 250c, which may be incorporated into the system 40 of the present invention. Transformer 250c is provided with the previously described windings 252, 258 and 264 and conductive sheaths 280, 288 and 290. The windings 252, 258 and 264 and conductive windings 280, 288 and 290 of transformer 250c are arranged in the same order relative to the center leg 274 of core 270 as the same windings and conductive sheaths of transformer 250b.

[0101] The difference between transformers 250b and 250c is that transformer 250c has three transformer control sub-windings 246a, 246b and 246c instead of a single leakage control winding. Physically, sub-windings 246a, 246b and 246c are arranged in the same position relative to windings 252, 256 and 264, and single winding 246 is positioned relative to the same winding in transformer 250b. In some / but not all forms of the invention, the turns of wire forming the leakage control windings 246a, 246b and 246c occupy the same number of layers as the winding turns of the single leakage control winding 246a.

[0102] from Fig.11 As can be seen in FIG. 1 , the high side of the sensing winding 256 is connected to the voltage measurement circuit 66. The low side of the sensing winding 256 is grounded. The inner conductive layer 280 and the middle conductive layer 288 are connected to the low side of the secondary winding 264, respectively.

[0103] Integral to the transformer 250c is a switch array 294. The switch array 294 can be physically attached to the transformer 250c or separate from the transformer 250c. The opposite ends of each sub-winding 246a, 246b and 246c are connected to the switch array 294. Also connected to the switch array 294 is an external conductive winding 290. The switch array 294 also has a ground connection. Inside the switch array 294 are many switches, not shown in the figure. The switches inside the switch array are configured to: connect the high side of any one of the sub-windings 246a, 246b, 246c to the external conductive cladding group 290; connect the low side of the sub-winding to the high side of the external winding; and ground the low side of any one of the self-windings.

[0104] As with transformer 250b, transformer 250c is configured such that conductive sheaths 280 and 288 function as one plate of capacitor 248. Conductive sheath 290 functions as a second plate of capacitor 248.

[0105] The transformer 250c is further formed so that by selectively setting the switches, switch arrays 294, 296 are formed. By selectively setting the switches of the switch array 294, any one of the sub-windings 246a, 246b or 246c, any combination of two of the sub-windings or all three of the sub-windings can be connected between the outer conductive sheath 290 and ground. This means that any one, two or all of the sub-windings 246a, 246b and 246c can be used as leakage control windings for matching current sources. This feature of the present invention helps to adjust the matching current source of the transformer 250c to ensure that the current i output by the source is M Basically equal to the high side parasitic capacitance C PH This adjustment process is typically performed after the transformer 250c is assembled or after the transformer 250c is installed to the rest of the console 50.

[0106] The foregoing is directed to specific forms of the invention. Alternative forms of the invention may have different features than those described.

[0107] For example, features of different forms of the invention may be combined. Thus, the leakage control sub-windings 246a, 246b, 246c and switch array 294 of transformer 250c may be incorporated into transformers 250, 250a and 250b.

[0108] In forms of the invention where there are a plurality of leakage control windings that are selectively connected together to form a matched current source, there may be two or four or more individual windings.

[0109] The structures of the components forming the invention may also be different from those described. For example, some forms of the invention may include a transformer having an E / I core assembly, a U core assembly, a U / I core assembly or an I core.

[0110] In some forms of the invention it may not be necessary to provide the transformer with an internal sensing coil.

[0111] Other components for forming the capacitor 248 integral with the matching current source are also possible. Thus, in some forms of the invention, a conductive sheath may be attached to the low side of the secondary winding 264. The conductive sheath may be sufficiently close to a portion of the high side of the leakage control winding 246 that the conductive sheath serves as one plate of the capacitor 248 and a portion of the leakage control winding serves as a second plate of the capacitor 248.

[0112] Likewise, it is not required that in all forms of the invention, the control station be configured so that an AC voltage is generated across the transformer primary winding by applying a voltage to the center tap of the winding and periodically grounding the opposite ends of the winding. In alternative forms of the invention, the AC voltage source may be an AC signal source applied to opposite ends of the transformer primary winding 252. Likewise, in all configurations of the invention, the AC voltage applied or induced across the transformer may be constant, depending on the specific application of the transformer.

[0113] Although in most forms of the invention the transformer has at least one conductive sheath, it is not required that in all forms of the invention the transformer have multiple conductive sheaths. When there is a single conductive sheath, the sheath typically, but not always, forms one plate of a capacitor 248 that matches the current source. If there are three conductive sheaths, it is not required that each sheath form part of capacitor 248. Two sheaths may form a plate or plates of capacitor 248; the third sheath is a shield. Likewise, transformers having four or more plates are within the scope of the invention. Thus, it is within the scope of the invention for a transformer to include five conductive sheaths, specifically where: two sheaths form a first plate of capacitor 248; two sheaths form a second plate of capacitor 248; and a single sheath serves as a shield around the outer winding of the capacitor.

[0114] Likewise, the order of windings 246, 252, 256, and 264 relative to the center of core 270 is different than that already described.

[0115] Not all features may be present in all forms of the invention. For example, alternative consoles of the invention may include a matching current source that is not completely built into the transformer. In some forms of the invention, the transformer may include a set of leakage current windings 246a, 246b, and 246c and a switch that selectively connects the windings together. In these forms of the invention, the capacitor 248 integral with the matching current source may be separate from the transformer 250.

[0116] Although not shown, it will be appreciated that in some embodiments of these forms of the invention, transistors (typically FETs) may be used as individual switches of the switch array 294 .

[0117] With regard to the feature of providing a plurality of leakage current windings selectively connected together for matching current sources, it should be understood that it is not required that there are always three sub-windings that can be selectively connected together. In some forms of the invention, there may be only two sub-windings. In other forms of the invention, there may be four or more sub-windings that can be selectively connected together. In addition, the present invention may have a structure in which one of the plurality of sub-windings is always a sub-winding of the leakage control winding.

[0118] In most forms of the invention, the conductive layer serving as the capacitor plate extends 360° around the underlying transformer winding or windings. In some forms of the invention, the conductive layer may not extend completely around the underlying winding or windings. Alternatively, the conductive layer may extend more than 360° around the windings. It should be understood that regardless of the extent to which the layer extends around the windings, opposite sides of the layer should not be electrically connected to each other. This is to prevent the conductive layer from shorting.

[0119] It should also be understood that the electric surgical tools to which the consoles of various forms of the present invention supply drive signals are not limited to tools in which the power generation unit includes a set of ultrasonic transducers. Other systems of the present invention can be configured such that the tool power generation unit is a device that emits light (photon energy). Another system of the present invention may include a handpiece with a monopolar or bipolar electrode assembly. In this type of system, the conductor extending through the handpiece can be considered to be a power generation unit. One or more electrodes applied to the tissue will be energy application. This type of system operates by applying an electric current to the tissue. The electric current heats the tissue to cause the desired ablation or cauterization of the tissue.

[0120] Furthermore, the console of the present invention, as well as the transformer of the present invention, can be used for purposes other than applying an AC signal in a relatively low leakage current manner to a device other than an electric surgical handpiece. Such devices include bipolar forceps. In this type of assembly, the tip of the forceps can be considered the energy applicator of the handpiece. The conductors integral with the arms of the forceps, to which the AC signal is applied at the tip, can be considered the power generating unit of the handpiece.

[0121] Therefore, it is the object of the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention.

Claims

1. An electric surgical tool system, comprising: A surgical tool including a power generating unit; A control console for supplying a driving signal to a power generation unit of a surgical tool, the control console comprising: a transformer having a primary winding to which an AC voltage is applied and a secondary winding to which a drive signal is induced so that the drive signal can be applied to a power generation unit of a surgical tool; a matching current source connected to the secondary winding and configured to generate a current that at least partially cancels a leakage current present in the drive signal caused by parasitic capacitance; a high-side conductor and a low-side conductor connected to different ends of the secondary winding and a power generation unit of a surgical tool, respectively, to supply a driving signal induced on the secondary winding to the power generation unit of the surgical tool; and A cable connected to a console and a surgical tool, the cable comprising a portion of the high-side conductor, a portion of the low-side conductor, and an inner shield through which the portion of the high-side conductor extends, wherein the low-side conductor is electrically coupled to the inner shield.

2. The electric surgical tool system according to claim 1, wherein the matching current source comprises: A leakage control winding, an AC voltage existing on the primary winding induces a voltage on the leakage control winding, and a capacitor connected between the leakage control winding and the secondary winding, the leakage control winding and the capacitor being built in a transformer. 3 . The electric surgical tool system of claim 2 , wherein a set of turns of at least one of the leakage control winding and the secondary winding of the transformer are configured to function as plates of a capacitor. 4 . The electric surgical tool system according to claim 2 , wherein the leakage control winding is arranged outside the primary and secondary windings.

5. The electric surgical tool system according to any one of claims 2 to 4, further comprising a sensing winding located inside the transformer for measuring a voltage of the driving signal induced on the secondary winding. 6 . The powered surgical tool system of claim 5 , wherein the sensing winding is disposed between components of the transformer that form the capacitor.

7. An electric surgical tool system according to any one of claims 2-4, wherein the rated voltage of the capacitor is greater than 500 volts.

8. An electric surgical tool system according to any one of claims 1-4, wherein the matching current source is coupled to the low-side conductor and is configured to generate a current substantially equal to a parasitic current present on the high-side conductor.

9. The powered surgical tool system of any one of claims 1-4, wherein the portion of the low-side conductor extends through the inner shield.

10. The electric surgical tool system according to any one of claims 1-4 further includes a conductive material layer inside the transformer and connected to the end of the secondary winding connected to the low-side conductor, the conductive material layer being wound around the primary winding and the secondary winding to serve as an electromagnetic shield.

11. The electric surgical tool system according to any one of claims 1-4, wherein the cable and the surgical instrument are assembled into a single unit, the cable being detachably connectable to the console to form the high-side conductor and the low-side conductor.

12. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: A transformer, comprising: a primary winding to which an AC voltage is applied; a secondary winding on which a driving signal is induced, the driving signal being applied to a power generation unit of the surgical tool, the secondary winding including a high-side terminal and a low-side terminal for supplying the driving signal to the power generation unit of the surgical tool; a leakage control winding on which the AC voltage present on the primary winding induces a voltage for generating a current that at least partially cancels a leakage current present in the drive signal caused by a parasitic capacitance; and A layer of conductive material is connected to the low side end of the secondary winding and is wound around the primary winding, the secondary winding and the leakage control winding to serve as an electromagnetic shield.

13. The console of claim 12, further comprising a capacitor inside the transformer and connected between the leakage control winding and the secondary winding.

14. The console according to claim 12 or 13, wherein the leakage control winding is provided outside the primary and secondary windings.

15. A transformer for supplying a driving signal to a power generation unit of a surgical tool, the transformer comprising: a primary winding for receiving an AC voltage; a secondary winding for sensing a driving signal applied to a power generation unit of a surgical tool, the secondary winding including a high-side terminal and a low-side terminal for supplying the driving signal to the power generation unit of the surgical tool; a leakage control winding, wherein the AC voltage present on the primary winding is configured to induce a voltage for generating a current that at least partially cancels a leakage current present in the drive signal caused by the parasitic capacitance; and A layer of conductive material is connected to the low side end of the secondary winding and is wound around the primary winding, the secondary winding and the leakage control winding to serve as an electromagnetic shield.

16. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: a transformer having a primary winding to which an AC voltage is applied; and a secondary winding on which a drive signal is induced so that the drive signal can be applied to a power generation unit of the surgical tool; and A matching current source is provided inside the transformer, the matching current source comprising a leakage control winding and a capacitor, the AC voltage present on the primary winding induces a voltage on the leakage control winding, the capacitor is connected between the leakage control winding and the secondary winding, and the matching current source is designed to generate a current that at least partially offsets the leakage current present in the drive signal caused by the parasitic capacitance.

17. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: a transformer having a primary winding to which an AC voltage is applied; and a secondary winding on which a drive signal is induced so that the drive signal can be applied to a power generation unit of the surgical tool; and a matching current source, comprising a leakage control winding and a capacitor, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding, the capacitor being connected between the leakage control winding and the secondary winding, the matching current source being designed to generate a current that at least partially cancels the leakage current present in the drive signal caused by the parasitic capacitance, Therein, the capacitor includes at least one plate formed by a layer of conductive material wound around at least one of the primary winding and the secondary winding of the transformer.

18. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: a transformer having a primary winding to which an AC voltage is applied; and a secondary winding on which a drive signal is induced so that the drive signal can be applied to a power generation unit of the surgical tool; and a matching current source, comprising a leakage control winding and a capacitor, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding, the capacitor being connected between the leakage control winding and the secondary winding, the matching current source being designed to generate a current that at least partially cancels the leakage current present in the drive signal caused by the parasitic capacitance, Therein, a group of turns of at least one of the leakage control winding and the secondary winding of the transformer is used as a plate of a capacitor.

19. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: a transformer having a primary winding to which an AC voltage is applied; and a secondary winding on which a drive signal is induced so that the drive signal can be applied to a power generation unit of the surgical tool; and A matching current source includes a leakage control winding and a capacitor, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding, the capacitor is connected between the leakage control winding and the secondary winding, and the rated voltage of the capacitor is greater than 500 volts. The matching current source is designed to generate a current that at least partially offsets the leakage current present in the drive signal caused by parasitic capacitance.

20. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: A transformer, comprising: a primary winding to which an AC voltage is applied; a secondary winding on which a drive signal is induced so that the drive signal can be applied to a power generation unit of the surgical tool; and A leakage control winding, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding for generating a current, wherein the current at least partially offsets the leakage current present in the drive signal caused by the parasitic capacitance, and the leakage control winding is arranged outside the primary and secondary windings.

21. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: A transformer, comprising: a primary winding to which an AC voltage is applied; a secondary winding on which a drive signal is induced so that the drive signal can be applied to a power generation unit of the surgical tool; a leakage control winding, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding for generating a current that at least partially cancels a leakage current present in the drive signal caused by a parasitic capacitance; and A sensing winding is used to measure the voltage of the drive signal induced on the secondary winding.

22. A control console for supplying a drive signal to a power generation unit of a surgical tool via a high-side conductor and a low-side conductor, the console comprising: a transformer having a primary winding to which an AC voltage is applied; and a secondary winding on which a drive signal is induced, the drive signal being applied to a power generation unit of the surgical tool via a high-side conductor and a low-side conductor; and A matching current source includes a leakage control winding, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding, and the matching current source is designed to generate a current that is substantially equal to the parasitic current present on the high-side conductor and at least partially offsets the leakage current present in the drive signal caused by the parasitic current.

23. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: A transformer, comprising: a primary winding to which an AC voltage is applied; a secondary winding on which a drive signal is induced, the drive signal being applied to a power generation unit of the surgical tool; and a leakage control winding, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding for generating a current that at least partially offsets the leakage current present in the drive signal caused by the parasitic capacitance, The primary winding is formed with turns wound in a first direction, and the secondary winding and the leakage control winding are respectively formed with turns wound in a second direction opposite to the first direction.

24. A console for supplying a driving signal to a power generation unit of a surgical tool, the console comprising: A transformer, comprising: a primary winding to which an AC voltage is applied; a secondary winding on which a drive signal is induced, the drive signal being applied to a power generation unit of the surgical tool; and a leakage control winding, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding for generating a current that at least partially offsets the leakage current present in the drive signal caused by the parasitic capacitance, The primary winding, the secondary winding and the leakage control winding are respectively formed with turns wound in the same direction.

25. A transformer for supplying a driving signal to a power generation unit of a surgical tool, the transformer comprising: a primary winding for receiving an AC voltage; a secondary winding for sensing a drive signal applied to a power generation unit of a surgical tool; and A leakage control winding is provided, wherein the AC voltage present on the primary winding induces a voltage on the leakage control winding for generating a current which at least partially cancels the leakage current present in the drive signal caused by the parasitic capacitance.

26. The transformer of claim 25, wherein the leakage control winding is disposed outside the primary and secondary windings. 27 . The transformer according to claim 25 , wherein the leakage control winding is disposed outside the primary winding, and the secondary winding is disposed outside the leakage control winding.

28. The transformer according to any one of claims 25-27, further comprising a layer of conductive material wound around the primary winding, the secondary winding and the leakage control winding to act as an electromagnetic shield.

29. The transformer according to any one of claims 25-27 further includes a built-in capacitor connected between the leakage control winding and the secondary winding, the capacitor and the leakage control winding forming a matching current source within the transformer, and the matching current source is designed to generate a current that at least partially offsets the leakage current present in the drive signal caused by parasitic capacitance.

30. The transformer of claim 29, wherein the capacitor comprises a plate formed from a layer of conductive material wound around at least one of the primary winding and the secondary winding of the transformer.

31. The transformer of claim 29, wherein a group of turns of at least one of the leakage control winding and the secondary winding of the transformer function as plates of a capacitor.

32. The transformer according to any one of claims 25-27, further comprising an E-shaped core, the E-shaped core comprising outer legs and a center leg located between the outer legs, wherein the primary winding, the secondary winding and the leakage control winding are wound around the center leg inside the outer legs.

33. The transformer of any one of claims 25-27, further comprising a sensing winding for measuring a voltage of the drive signal induced on the secondary winding.

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