USRE47996E1 - Surgical generator for ultrasonic and electrosurgical devices - Google Patents

Surgical generator for ultrasonic and electrosurgical devices Download PDF

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Publication number
USRE47996E1
USRE47996E1 US15/795,156 US201715795156A USRE47996E US RE47996 E1 USRE47996 E1 US RE47996E1 US 201715795156 A US201715795156 A US 201715795156A US RE47996 E USRE47996 E US RE47996E
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Prior art keywords
generator
switch
tissue
surgical
surgical device
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US15/795,156
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Douglas J. Turner
Jeffrey L. Aldridge
Vincent P. Battaglia, JR.
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Cilag GmbH International
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Ethicon LLC
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Priority claimed from US12/896,360 external-priority patent/US9060775B2/en
Priority claimed from US13/251,766 external-priority patent/US10441345B2/en
Priority claimed from US13/448,175 external-priority patent/US9168054B2/en
Application filed by Ethicon LLC filed Critical Ethicon LLC
Priority to US15/795,156 priority Critical patent/USRE47996E1/en
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Assigned to CILAG GMBH INTERNATIONAL reassignment CILAG GMBH INTERNATIONAL ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ETHICON LLC
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Definitions

  • Various embodiments are directed to surgical devices, and generators for supplying energy to surgical devices, for use in open or minimally invasive surgical environments.
  • Ultrasonic surgical devices such as ultrasonic scalpels, are finding increasingly widespread applications in surgical procedures by virtue of their unique performance characteristics. Depending upon specific device configurations and operational parameters, ultrasonic surgical devices can provide substantially simultaneous transection of tissue and homeostasis by coagulation, desirably minimizing patient trauma.
  • An ultrasonic surgical device may comprise a handpiece containing an ultrasonic transducer, and an instrument coupled to the ultrasonic transducer having a distally-mounted end effector (e.g., a blade tip) to cut and seal tissue.
  • the instrument may be permanently affixed to the handpiece. In other cases, the instrument may be detachable from the handpiece, as in the case of a disposable instrument or an instrument that is interchangeable between different.
  • the end effector transmits ultrasonic energy to tissue brought into contact with the end effector to realize cutting and sealing action.
  • Ultrasonic surgical devices of this nature can be configured for open surgical use, laparoscopic, or endoscopic surgical procedures including robotic-assisted procedures.
  • Ultrasonic energy cuts and coagulates tissue using temperatures lower than those used in electrosurgical procedures and can be transmitted to the end effector by an ultrasonic generator in communication with the handpiece. Vibrating at high frequencies (e.g., 55,500 times per second), the ultrasonic blade denatures protein in the tissue to form a sticky coagulum. Pressure exerted on tissue by the blade surface collapses blood vessels and allows the coagulum to form a haemostatic seal. A surgeon can control the cutting speed and coagulation by the force applied to the tissue by the end effector, the time over which the force is applied and the selected excursion level of the end effector.
  • the ultrasonic transducer may be modeled as an equivalent circuit comprising first branch having a static capacitance and a second “motional” branch having a serially connected inductance, resistance and capacitance that define the electromechanical properties of a resonator.
  • Known ultrasonic generators may include a tuning inductor for tuning out the static capacitance at a resonant frequency so that substantially all of generator's drive signal current flows into the motional branch. Accordingly, by using a tuning inductor, the generator's drive signal current represents the motional branch current, and the generator is thus able to control its drive signal to maintain the ultrasonic transducer's resonant frequency.
  • the tuning inductor may also transform the phase impedance plot of the ultrasonic transducer to improve the generator's frequency lock capabilities.
  • the tuning inductor must be matched with the specific static capacitance of an ultrasonic transducer at the operational resonance frequency. In other words, a different ultrasonic transducer having a different static capacitance requires a different tuning inductor.
  • the generator's drive signal exhibits asymmetrical harmonic distortion that complicates impedance magnitude and phase measurements.
  • the accuracy of impedance phase measurements may be reduced due to harmonic distortion in the current and voltage signals.
  • Electrosurgical devices for applying electrical energy to tissue in order to treat and/or destroy the tissue are also finding increasingly widespread applications in surgical procedures.
  • An electrosurgical device may comprise a handpiece and an instrument having a distally-mounted end effector (e.g., one or more electrodes). The end effector can be positioned against the tissue such that electrical current is introduced into the tissue.
  • Electrosurgical devices can be configured for bipolar or monopolar operation. During bipolar operation, current is introduced into and returned from the tissue by active and return electrodes, respectively, of the end effector. During monopolar operation, current is introduced into the tissue by an active electrode of the end effector and returned through a return electrode (e.g., a grounding pad) separately located on a patient's body.
  • a return electrode e.g., a grounding pad
  • Heat generated by the current flow through the tissue may form haemostatic seals within the tissue and/or between tissues and thus may be particularly useful for sealing blood vessels, for example.
  • the end effector of an electrosurgical device may also comprise a cutting member that is movable relative to the tissue and the electrodes to transect the tissue.
  • RF energy is a form of electrical energy that may be in the frequency range of 300 kHz to 1 MHz.
  • an electrosurgical device can transmit low frequency RF energy through tissue, which causes ionic agitation, or friction, in effect resistive heating, thereby increasing the temperature of the tissue. Because a sharp boundary may be created between the affected tissue and the surrounding tissue, surgeons can operate with a high level of precision and control, without sacrificing un-targeted adjacent tissue.
  • the low operating temperatures of RF energy may be useful for removing, shrinking, or sculpting soft tissue while simultaneously sealing blood vessels.
  • RF energy may work particularly well on connective tissue, which is primarily comprised of collagen and shrinks when contacted by heat.
  • ultrasonic and electrosurgical devices Due to their unique drive signal, sensing and feedback needs, ultrasonic and electrosurgical devices have generally required different generators. Additionally, in cases where the instrument is disposable or interchangeable with a handpiece, ultrasonic and electrosurgical generators are limited in their ability to recognize the particular instrument configuration being used and to optimize control and diagnostic processes accordingly. Moreover, capacitive coupling between the non-isolated and patient-isolated circuits of the generator, especially in cases where higher voltages and frequencies are used, may result in exposure of a patient to unacceptable levels of leakage current.
  • ultrasonic and electrosurgical devices have generally required different user interfaces for the different generators.
  • one user interface is configured for use with an ultrasonic instrument whereas a different user interface may be configured for use with an electrosurgical instrument.
  • Such user interfaces include hand and/or foot activated user interfaces such as hand activated switches and/or foot activated switches.
  • additional user interfaces that are configured to operate with both ultrasonic and/or electrosurgical instrument generators also are contemplated.
  • Additional user interfaces for providing feedback, whether to the user or other machine, are contemplated within the subsequent disclosure to provide feedback indicating an operating mode or status of either an ultrasonic and/or electrosurgical instrument.
  • Providing user and/or machine feedback for operating a combination ultrasonic and/or electrosurgical instrument will require providing sensory feedback to a user and electrical/mechanical/electro-mechanical feedback to a machine.
  • Feedback devices that incorporate visual feedback devices (e.g., an LCD display screen, LED indicators), audio feedback devices (e.g., a speaker, a buzzer) or tactile feedback devices (e.g., haptic actuators) for use in combined ultrasonic and/or electrosurgical instruments are contemplated in the subsequent disclosure.
  • the generator may comprise a power amplifier to receive a time-varying drive signal waveform.
  • the drive signal waveform may be generated by a digital-to-analog conversion of at least a portion of a plurality of drive signal waveform samples.
  • An output of the power amplifier may be for generating a drive signal.
  • the drive signal may comprise one of: a first drive signal to be communicated to an ultrasonic surgical device, a second drive signal to be communicated to an electrosurgical device.
  • the generator may also comprise a sampling circuit to generate samples of current and voltage of the drive signal when the drive signal is communicated to the surgical device.
  • the generator may also comprise at least one device programmed to, for each drive signal waveform sample and corresponding set of current and voltage samples, store the current and voltage samples in a memory of the at least one device to associate the stored samples with the drive signal waveform sample.
  • the at least one device may also be programmed to, when the drive signal comprises the first drive signal: determine a motional branch current sample of the ultrasonic surgical device based on the stored current and voltage samples, compare the motional branch current sample to a target sample selected from a plurality of target samples that define a target waveform, the target sample selected based on the drive signal waveform sample, determine an amplitude error between the target sample and the motional branch current sample, and modify the drive signal waveform sample such that an amplitude error determined between the target sample and a subsequent motional branch current sample based on current and voltage samples associated with the modified drive signal waveform sample is reduced.
  • the generator may comprise a memory and a device coupled to the memory to receive for each of a plurality of drive signal waveform samples used to synthesize the drive signal, a corresponding set of current and voltage samples of the drive signal.
  • the device may store the samples in a memory of the device to associate the stored samples with the drive signal waveform sample.
  • the device may, when the drive signal comprises a first drive signal to be communicated to an ultrasonic surgical device, determine a motional branch current sample of the ultrasonic surgical device based on the stored samples, compare the motional branch current sample to a target sample selected from a plurality of target samples that define a target waveform, the target sample selected based on the drive signal waveform sample, determine an amplitude error between the target sample and the motional branch current sample, and modify the drive signal waveform sample such that an amplitude error determined between the target sample and a subsequent motional branch current sample based on current and voltage samples associated with the modified drive signal waveform sample is reduced.
  • the method may comprise, at each of a plurality of frequencies of the transducer drive signal, oversampling a current and voltage of the transducer drive signal, receiving, by a processor, the current and voltage samples, and determining, by the processor, the motional branch current based on the current and voltage samples, a static capacitance of the ultrasonic transducer and the frequency of the transducer drive signal.
  • the method may comprise generating a transducer drive signal by selectively recalling, using a direct digital synthesis (DDS) algorithm, drive signal waveform samples stored in a look-up table (LUT), generating samples of current and voltage of the transducer drive signal when the transducer drive signal is communicated to the surgical device, determining samples of the motional branch current based on the current and voltage samples, a static capacitance of the ultrasonic transducer and a frequency of the transducer drive signal, comparing each sample of the motional branch current to a respective target sample of a target waveform to determine an error amplitude, and modifying the drive signal waveform samples stored in the LUT such that an amplitude error between subsequent samples of the motional branch current and respective target samples is reduced.
  • DDS direct digital synthesis
  • a surgical generator for providing a drive signal to a surgical device may comprise a first transformer and a second transformer.
  • the first transformer may comprise a first primary winding and a first secondary winding.
  • the second transformer may comprise a second primary winding and a second secondary winding.
  • the surgical generator may further comprise a generator circuit to generate the drive signal.
  • the generator circuit may be electrically coupled to the first primary winding to provide the drive signal across the first primary winding.
  • the surgical generator may also comprise a patient-side circuit electrically isolated from the generator circuit.
  • the patient-side circuit may be electrically coupled to the first secondary winding.
  • the patient-side circuit may comprise first and second output lines to provide the drive signal to the surgical device.
  • the surgical generator may comprise a capacitor.
  • the capacitor and the second secondary winding may be electrically coupled in series between the first output line and ground.
  • a surgical generator for providing a drive signal to a surgical device may comprise a first transformer, a patient-side circuit, and a capacitor.
  • the first transformer may comprise a primary winding, a first secondary winding, and a second secondary winding. A polarity of the first secondary winding relative to the primary winding may be opposite the polarity of the second secondary winding.
  • the generator circuit may generate the drive signal and may be electrically coupled to the first primary winding to provide the drive signal across the first primary winding.
  • the patient-side circuit may be electrically isolated from the generator circuit and may be electrically coupled to the first secondary winding.
  • the patient-side circuit may comprise first and second output lines to provide the drive signal to the surgical device.
  • the capacitor and second secondary winding may be electrically coupled in series between the first output line and ground.
  • a surgical generator for providing a drive signal to a surgical device may comprise a first transformer, a generator circuit, a patient-side circuit and a capacitor.
  • the first transformer may comprise a primary winding and a secondary winding.
  • the generator circuit may generate the drive signal and may be electrically coupled to the first primary winding to provide the drive signal across the first primary winding.
  • the patient-side circuit may be electrically isolated from the generator circuit and may be electrically coupled to the secondary winding. Further, the patient-side circuit may comprise first and second output lines to provide the drive signal to the surgical device.
  • the capacitor may be electrically coupled to the primary winding and to the first output line.
  • a surgical generator for providing a drive signal to a surgical device may comprise a first transformer, a generator circuit, a patient-side circuit, as well as first, second and third capacitors.
  • the first transformer may comprise a primary winding and a secondary winding.
  • the generator circuit may generate the drive signal and may be electrically coupled to the first primary winding to provide the drive signal across the first primary winding.
  • the patient-side circuit may be electrically isolated from the generator circuit and may be electrically coupled to the secondary winding. Further, the patient-side circuit may comprise first and second output lines to provide the drive signal to the surgical device.
  • a first electrode of the first capacitor may be electrically coupled to the primary winding.
  • a first electrode of the second capacitor may be electrically coupled to the first output line and a second electrode of the second capacitor may be electrically coupled to a second electrode of the first capacitor.
  • a first electrode of the third capacitor may be electrically coupled to the second electrode of the first capacitor and the second electrode of the second capacitor.
  • a second electrode of the third capacitor may be electrically coupled to ground.
  • control circuits for surgical devices are also disclosed.
  • the control circuit may comprise a first circuit portion comprising at least one first switch.
  • the first circuit portion may communicate with a surgical generator over a conductor pair.
  • the control circuit may also comprise a second circuit portion comprising a data circuit element.
  • the data circuit element may be disposed in an instrument of the surgical device and transmit or receive data.
  • the data circuit element may implement data communications with the surgical generator over at least one conductor of the conductor pair.
  • the control circuit may comprise a first circuit portion comprising at least one first switch.
  • the first circuit portion may communicate with a surgical generator over a conductor pair.
  • the control circuit may also comprise a second circuit portion comprising a data circuit element.
  • the data circuit element may be disposed in an instrument of the surgical device and transmit or receive data.
  • the data circuit element may implement data communications with the surgical generator over at least one conductor of the conductor pair.
  • the first circuit portion may receive a first interrogation signal transmitted from the surgical generator in a first frequency band.
  • the data circuit element may communicate with the surgical generator using an amplitude-modulated communication protocol transmitted in a second frequency band.
  • the second frequency band may be higher than the first frequency band.
  • the control circuit may comprise a first circuit portion comprising at least one first switch.
  • the first circuit portion may receive a first interrogation signal transmitted from a surgical generator over a conductor pair.
  • the control circuit may also comprise a second circuit portion comprising at least one of a resistive element and an inductive element disposed in an instrument of the device.
  • the second circuit portion may receive a second interrogation signal transmitted from the surgical generator over the conductor pair.
  • the second circuit portion may be frequency-band separated from the first circuit portion.
  • a characteristic of the first interrogation signal, when received through the first circuit portion may be indicative of a state of the at least one first switch.
  • a characteristic of the second interrogation signal, when received through the second circuit portion may uniquely identify the instrument of the device.
  • control circuit may comprise a first circuit portion comprising a first switch network and a second switch network.
  • the first switch network may comprise at least one first switch
  • the second switch network may comprise at least one second switch.
  • the first circuit portion may communicate with a surgical generator over a conductor pair.
  • the control circuit may also comprise a second circuit portion comprising a data circuit element.
  • the data circuit element may be disposed in an instrument of the surgical device and may transmit or receive data.
  • the data circuit element may be in data communication with the surgical generator over at least one conductor of the conductor pair.
  • a surgical generator for providing a drive signal to a surgical device may comprise a surgical generator body having an aperture.
  • the surgical generator may also comprise a receptacle assembly positioned in the aperture.
  • the receptacle assembly may comprise a receptacle body and a flange having an inner wall and an outer wall.
  • the inner wall may be comprised of at least one curved section and at least one linear section.
  • the inner wall may define a cavity.
  • a central protruding portion may be positioned in the cavity and may comprise a plurality of sockets and a magnet.
  • An outer periphery of the central protruding portion may comprise at least one curved section and at least one linear section.
  • a surgical instrument may comprises an electrical connector assembly.
  • the electrical connector assembly may comprise a flange defining a central cavity and a magnetically compatible pin extending into the central cavity.
  • the electrical connector assembly may comprise a circuit board and a plurality of electrically conductive pins coupled to the circuit board. Each of the plurality of electrically conductive pins may extend into the central cavity.
  • the electrical connector assembly may further comprise a strain relief member and a boot.
  • a surgical instrument system may comprise a surgical generator comprising a receptacle assembly.
  • the receptacle assembly may comprise at least one curved section and at least one linear portion.
  • the surgical instrument system may comprise a surgical instrument comprising a connector assembly and an adapter assembly operatively coupled to the receptacle assembly and the connector assembly.
  • the adapter assembly may comprise a distal portion contacting the receptacle assembly.
  • the distal portion may comprise a flange with the flange having at least one curved section and at least one linear portion.
  • the adapter assembly may comprise a proximal portion contacting the connector assembly.
  • the proximal portion may define a cavity dimensioned to receive at least a portion of the connector assembly.
  • the adapter assembly may further comprise a circuit board.
  • methods to control electrical power provided to tissue via first and second electrodes may comprise providing a drive signal to the tissue via the first and second electrodes and modulating a power provided to the tissue via the drive signal based on a sensed tissue impedance according to a first power curve.
  • the first power curve may define, for each of a plurality of potential sensed tissue impedances, a first corresponding power.
  • the methods may also comprise monitoring a total energy provided to the tissue via the first and second electrodes. When the total energy reaches a first energy threshold, the methods may comprise determining whether an impedance of the tissue has reached a first impedance threshold.
  • the methods may further comprise, conditioned upon the impedance of the tissue failing to reach the first impedance threshold, modulating the power provided to the tissue via the drive signal based on the sensed tissue impedance according to a second power curve.
  • the second power curve may define, for each of the plurality of potential sensed tissue impedances, a second corresponding power.
  • methods for controlling electrical power provided to tissue via first and second electrodes may comprise providing a drive signal to the tissue via the first and second electrodes and determining a power to be provided to the tissue.
  • the determining may comprise receiving an indication of a sensed tissue impedance; determining a first corresponding power for the sensed tissue impedance according to a power curve; and multiplying the corresponding power by a multiplier.
  • the power curve may define a corresponding power for each of a plurality of potential sensed tissue impedances.
  • the methods may further comprise modulating the drive signal to provide the determined power to the tissue and, conditioned upon the impedance of the tissue failing to reach a first impedance threshold, increasing the multiplier as a function of the total energy provided to the tissue.
  • methods for controlling electrical power provided to tissue via first and second electrodes may comprise providing a drive signal to the tissue via the first and second electrodes and determining a power to be provided to the tissue.
  • the determining may comprise receiving an indication of a sensed tissue impedance; determining a first corresponding power for the sensed tissue impedance according to a power curve; and multiplying the corresponding power by a first multiplier to find a determined power.
  • the power curve may define a corresponding power for each of a plurality of potential sensed tissue impedances.
  • the methods may further comprise modulating the drive signal to provide the determined power to the tissue and monitoring a total energy provided to the tissue via the first and second electrodes.
  • the methods may comprise, when the total energy reaches a first energy threshold, determining whether the impedance of the tissue has reached a first impedance threshold; and, conditioned upon the impedance of the tissue not reaching the first impedance threshold, increasing the first multiplier by a first amount.
  • methods for controlling electrical power provided to tissue via a surgical device may comprise providing a drive signal to a surgical device; receiving an indication of an impedance of the tissue; calculating a rate of increase of the impedance of the tissue; and modulating the drive signal to hold the rate of increase of the impedance greater than or equal to a predetermined constant.
  • methods for controlling electrical power provided to tissue via a surgical device may comprise providing a drive signal.
  • a power of the drive signal may be proportional to a power provided to the tissue via the surgical device.
  • the methods may also comprise periodically receiving indications of an impedance of the tissue and applying a first composite power curve to the tissue, wherein applying the first composite power curve to the tissue comprises.
  • Applying the first composite power curve to the tissue may comprise modulating a first predetermined number of first composite power curve pulses on the drive signal; and for each of the first composite power curve pulses, determining a pulse power and a pulse width according to a first function of the impedance of the tissue
  • the methods may also comprise applying a second composite power curve to the tissue.
  • Applying the second composite power curve to the tissue may comprise modulating at least one second composite power curve pulse on the drive signal; and for each of the at least one second composite power curve pulses, determining a pulse power and a pulse width according to a second function of the impedance of the tissue.
  • a generator to generate a drive signal to a surgical device.
  • the generator includes an ultrasonic generator module to generate a first drive signal to drive an ultrasonic device, an electrosurgery/radio frequency (RF) generator module to generate a second drive signal to drive an electrosurgical device, and a foot switch coupled to each of the ultrasonic generator module and the electrosurgery/RF generator module.
  • the foot switch is configured to operate in a first mode when the ultrasonic device is coupled to the ultrasonic generator module and the foot switch is configured to operate in a second mode when the electrosurgical device is coupled to the electrosurgery/RF generator module.
  • a generator includes a user interface to provide feedback in accordance with the operation of any one of the ultrasonic device and the electrosurgical device in accordance with a predetermined algorithm.
  • a control circuit of a surgical device comprises a first circuit portion coupled to at least one switch operable between an open state and a closed state.
  • the first circuit portion communicates with a surgical generator over a conductor pair to receive a control signal to determine a state of the at least one switch.
  • a control circuit of a surgical device comprises a first circuit portion coupled to at least one switch operable between an open state and a closed state.
  • the first circuit portion communicates with a surgical generator over a conductor pair to receive a control signal from input terminals to determine a state of the at least one switch.
  • the control signal having a positive phase and a negative phase.
  • a first transistor is coupled between the input terminals, a first capacitor, and a first resistor is coupled in series with the first capacitor.
  • the first transistor During the positive phase of the control signal the first transistor is held in cutoff mode while the first capacitor charges to a predetermined voltage and during an initial portion of the negative phase of the control signal the first transistor transitions from cutoff mode to saturation mode and is held in saturation mode until the first capacitor discharges through the first resistor. During a final portion of the negative phase of the control signal the first transistor transitions from saturation mode to cutoff mode when the first capacitor voltage drops below a predetermined threshold.
  • a method comprises receiving a control signal at a control circuit of a surgical device and determining the state of the at least one switch based on the value of the resistor.
  • the control circuit comprising a first circuit portion coupled to at least one switch operable between an open state and a closed state.
  • the circuit portion to communicate with a surgical generator over a conductor pair to receive the control signal.
  • the first circuit portion comprising at least one resistor coupled to the at least one switch.
  • FIG. 1 illustrates one embodiment of a surgical system comprising a generator and various surgical instruments usable therewith;
  • FIG. 2 illustrates one embodiment of an example ultrasonic device that may be used for transection and/or sealing
  • FIG. 3 illustrates one embodiment of the end effector of the example ultrasonic device of FIG. 2 .
  • FIG. 4 illustrates one embodiment of an example electrosurgical device that may also be used for transection and sealing
  • FIGS. 5, 6 and 7 illustrate one embodiment of the end effector shown in FIG. 4 ;
  • FIG. 8 is a diagram of the surgical system of FIG. 1 ;
  • FIG. 9 is a model illustrating motional branch current in 30 one embodiment
  • FIG. 10 is a structural view of a generator architecture in one embodiment
  • FIGS. 11A-11C are functional views of a generator architecture in one embodiment
  • FIG. 12 illustrates a controller for monitoring input devices and controlling output devices in one embodiment
  • FIGS. 13A-13B illustrate structural and functional aspects of one embodiment of the generator
  • FIGS. 14-32 and 33A-33C illustrate embodiments of control circuits
  • FIG. 33D-33I illustrate embodiments of cabling and adaptor configurations for connecting various generators and various surgical instruments
  • FIG. 34 illustrates one embodiment of a circuit 300 for active cancellation of leakage current.
  • FIG. 35 illustrates one embodiment of a circuit that may be implemented by the generator of FIG. 1 to provide active cancellation of leakage current
  • FIG. 36 illustrates an alternative embodiment of a circuit that may be implemented by the generator of FIG. 1 to provide active cancellation of leakage current
  • FIG. 37 illustrates an alternative embodiment of a circuit that may be implemented by the generator of FIG. 1 to provide active cancellation of leakage current
  • FIG. 38 illustrates yet another embodiment of a circuit that may be implemented by the generator of FIG. 1 to provide active cancellation of leakage current
  • FIG. 39 illustrates an embodiment of a circuit that may be implemented by the generator of FIG. 1 to provide cancellation of leakage current
  • FIG. 40 illustrates another embodiment of a circuit that may be implemented by the generator of FIG. 1 to provide cancellation of leakage current
  • FIG. 41 illustrates a receptacle and connector interface in one embodiment
  • FIG. 42 is an exploded side view of the receptacle assembly in one embodiment
  • FIG. 43 is an exploded side view of the connector assembly in one embodiment
  • FIG. 44 is a perspective view of the receptacle assembly shown in FIG. 41 ;
  • FIG. 45 is a exploded perspective view of the receptacle assembly in one embodiment
  • FIG. 46 is a front elevation view of the receptacle assembly in one embodiment
  • FIG. 47 is a side elevation view of the receptacle assembly in one embodiment
  • FIG. 48 is an enlarged view of a socket in one embodiment
  • FIG. 49 is a perspective view of the connector assembly in one embodiment:
  • FIG. 50 is an exploded perspective view of the connector assembly in one embodiment
  • FIG. 51 is a side elevation view of a connector body in one embodiment
  • FIG. 52 is perspective view of the distal end of a connector body in one embodiment
  • FIG. 53 is perspective view of the proximal end of a connector body in one embodiment
  • FIG. 54 illustrates a ferrous pin in one embodiment
  • FIG. 55 illustrates electrically conductive pins and a circuit board in one embodiment
  • FIG. 56 illustrates a strain relief member in one embodiment
  • FIG. 57 illustrates a boot in one embodiment
  • FIG. 58 illustrates two adaptor assemblies in accordance with various non-limiting embodiments
  • FIG. 59 illustrates a surgical generator in one embodiment
  • FIG. 60 illustrates a connector assembly connected to an adaptor assembly in one embodiment
  • FIG. 61 illustrates an adaptor assembly inserted into a receptacle assembly of a surgical generator in one embodiment
  • FIG. 62 illustrates a connector assembly connected to an adaptor assembly in one embodiment
  • FIG. 63 illustrates a perspective view of a back panel of a generator in one embodiment
  • FIG. 64 illustrates a back panel of a generator in one embodiment
  • FIGS. 65 and 66 illustrate different portions of a back panel of a generator in one embodiment
  • FIG. 67 illustrates a neural network for controlling a generator in one embodiment
  • FIG. 68 illustrates measured temperature versus estimated temperature output by a surgical instrument controlled by a generator in one embodiment
  • FIG. 69 illustrates one embodiment of a chart showing example power curves
  • FIG. 70 illustrates one embodiment of a process flow for applying one or more power curves to a tissue bite
  • FIG. 71 illustrates one embodiment of a chart showing example power curves that may be used in conjunction with the process flow of FIG. 70 ;
  • FIG. 72 illustrates one embodiment of a chart showing example common shape power curves that may be used in conjunction with the process flow of FIG. 70 ;
  • FIG. 73A illustrates one embodiment of a routine that may be performed by a digital device of the generator of FIG. 1 to act upon a new tissue bite;
  • FIG. 73B illustrates one embodiment of a routine that may be performed by a digital device of the generator of FIG. 1 to monitor tissue impedance;
  • FIG. 73C illustrates one embodiment of a routine that may be performed by a digital device of the generator of FIG. 1 to provide one or more power curves to a tissue bite;
  • FIG. 74 illustrates one embodiment of a process flow for applying one or more power curves to a tissue bite
  • FIG. 75 illustrates one embodiment of a block diagram describing the selection and application of composite load curves by the generator of FIG. 1 ;
  • FIG. 76 illustrates shows a process flow illustrating one embodiment of the algorithm of FIG. 75 , as implemented by the generator of FIG. 1 ;
  • FIG. 77 illustrates one embodiment of a process flow for generating a first composite load curve pulse
  • FIG. 78 illustrates one embodiment of a pulse timing diagram illustrating an example application of the algorithm of FIG. 76 by the generator of FIG. 1 ;
  • FIG. 79 illustrates a graphical representation of drive signal voltage, current and power according to an example composite load curve
  • FIGS. 80-85 illustrate a graphical representations of example composite load curves
  • FIG. 86 illustrates one embodiment of a block diagram describing the application of an algorithm for maintaining a constant tissue impedance rate of change
  • FIG. 87 illustrates one embodiment of a control circuit comprising parallel switched resistance circuit with high speed data communication support and at least one data element comprising at least one memory device.
  • FIG. 88 is a graphical representation of one aspect of a control signal in the form of a constant current pulse waveform that may be generated by the signal conditioning circuit of the generator as shown in FIG. 10 .
  • FIG. 88A is a graphical representation of one aspect of a control signal in the form of the constant current pulse waveform of FIG. 88 showing numerical values of various features of the waveform according to one example embodiment.
  • FIG. 89 is a graphical representation of various detection regions associated with the aspect of the control signal shown in FIG. 88 .
  • FIG. 90 is a graphical representation of one aspect of a control signal in the form of a current pulse waveform measured at the generator with SW 1 closed and a zero ohm cable/connector impedance.
  • FIG. 90A is a graphical representation of one aspect of a control signal in the form of the current pulse waveform of FIG. 90 showing numerical values of various features of the waveform according to one example embodiment.
  • FIG. 91 is an oscilloscope trace of an actual measured analog-to-digital (ADC) input waveform using a generator and a control circuit.
  • ADC analog-to-digital
  • FIG. 92 illustrates another embodiment of a control circuit comprising parallel switched resistance circuit and at least one data element comprising at least one memory device memory device.
  • FIG. 93 illustrates one embodiment of a control circuit comprising a serial switched resistance circuit and at least one data element comprising at least one memory device.
  • FIG. 94 illustrates one embodiment of a control circuit comprising a serial switched resistance circuit with a precision voltage reference and at least one data element comprising at least one memory device.
  • FIG. 95 illustrates one embodiment of a control circuit comprising a variable frequency switched resistance circuit and at least one data element comprising at least one memory device.
  • FIG. 96 is a graphical representation of one embodiment of a detection method showing detection regions for the control circuit comprising a variable frequency switched resistance circuit and a memory device, as described in connection with FIG. 95 .
  • FIG. 97 illustrates one embodiment of a control circuit comprising a parallel switched resistance circuit with a precision voltage reference and at lease one data element comprising at least one memory device employing a variable slope waveform to determine switch states.
  • FIG. 98 is a graphical representation of one embodiment of a detection method showing detection regions for the control circuit comprising a variable ramp/slope switched resistance circuit and a memory device, as described in connection with FIG. 97 .
  • FIG. 99 illustrates one embodiment of a control circuit comprising a one-wire multi-switch input device.
  • Embodiments of the ultrasonic surgical devices can be configured for transecting and/or coagulating tissue during surgical procedures, for example.
  • Embodiments of the electrosurgical devices can be configured for transecting, coagulating, scaling, welding and/or desiccating tissue during surgical procedures, for example.
  • Embodiments of the generator utilize high-speed analog-to-digital sampling (e.g., approximately 200 ⁇ oversampling, depending on frequency) of the generator drive signal current and voltage, along with digital signal processing, to provide a number of advantages and benefits over known generator architectures.
  • the generator may determine the motional branch current of an ultrasonic transducer. This provides the benefit of a virtually tuned system, and simulates the presence of a system that is tuned or resonant with any value of the static capacitance (e.g., C 0 in FIG. 9 ) at any frequency.
  • control of the motional branch current may be realized by tuning out the effects of the static capacitance without the need for a tuning inductor. Additionally, the elimination of the tuning inductor may not degrade the generator's frequency lock capabilities, as frequency lock can be realized by suitably processing the current and voltage feedback data.
  • High-speed analog-to-digital sampling of the generator drive signal current and voltage, along with digital signal processing, may also enable precise digital filtering of the samples.
  • embodiments of the generator may utilize a low-pass digital filter (e.g., a finite impulse response (FIR) filter) that rolls off between a fundamental drive signal frequency and a second-order harmonic to reduce the asymmetrical harmonic distortion and EMI-induced noise in current and voltage feedback samples.
  • the filtered current and voltage feedback samples represent substantially the fundamental drive signal frequency, thus enabling a more accurate impedance phase measurement with respect to the fundamental drive signal frequency and an improvement in the generator's ability to maintain resonant frequency lock.
  • the accuracy of the impedance phase measurement may be further enhanced by averaging falling edge and rising edge phase measurements, and by regulating the measured impedance phase to 0°.
  • Various embodiments of the generator may also utilize the high-speed analog-to-digital sampling of the generator drive signal current and voltage, along with digital signal processing, to determine real power consumption and other quantities with a high degree of precision. This may allow the generator to implement a number of useful algorithms, such as, for example, controlling the amount of power delivered to tissue as the impedance of the tissue changes and controlling the power delivery to maintain a constant rate of tissue impedance increase.
  • Various embodiments of the generator may have a wide frequency range and increased output power necessary to drive both ultrasonic surgical devices and electrosurgical devices.
  • the lower voltage, higher current demand of electrosurgical devices may be met by a dedicated tap on a wideband power transformer, thereby eliminating the need for a separate power amplifier and output transformer.
  • sensing and feedback circuits of the generator may support a large dynamic range that addresses the needs of both ultrasonic and electrosurgical applications with minimal distortion.
  • Various embodiments may provide a simple, economical means for the generator to read from, and optionally write to, data circuit (e.g., a single-wire bus device, such as a one-wire protocol EEPROM known under the trade name “1-Wire”) disposed in an instrument attached to the handpiece using existing multi-conductor generator/handpiece cables.
  • data circuit e.g., a single-wire bus device, such as a one-wire protocol EEPROM known under the trade name “1-Wire”
  • the generator is able to retrieve and process instrument-specific data from an instrument attached to the handpiece. This may enable the generator to provide better control and improved diagnostics and error detection.
  • the ability of the generator to write data to the instrument makes possible new functionality in terms of, for example, tracking instrument usage and capturing operational data.
  • frequency band permits the backward compatibility of instruments containing a bus device with existing generators.
  • Disclosed embodiments of the generator provide active cancellation of leakage current caused by unintended capacitive coupling between non-isolated and patient-isolated circuits of the generator. In addition to reducing patient risk, the reduction of leakage current may also lessen electromagnetic emissions.
  • proximal and distal are used herein with reference to a clinician gripping a handpiece.
  • an end effector is distal with respect to the more proximal handpiece.
  • spatial terms such as “top” and “bottom” may also be used herein with respect to the clinician gripping the handpiece.
  • surgical devices are used in many orientations and positions, and these terms are not intended to be limiting and absolute.
  • FIG. 1 illustrates one embodiment of a surgical system 100 comprising a generator 102 configurable for use with surgical devices.
  • the generator 102 may be configurable for use with surgical devices of different types, including, for example, the ultrasonic surgical device 104 and electrosurgical or RF surgical device 106 .
  • the generator 102 is shown separate from the surgical devices 104 , 106 , in certain embodiments the generator 102 may be formed integrally with either of the surgical devices 104 , 106 to form a unitary surgical system.
  • FIG. 2 illustrates one embodiment of an example ultrasonic device 104 that may be used for transection and/or sealing.
  • the device 104 may comprise a hand piece 116 which may, in turn, comprise an ultrasonic transducer 114 .
  • the transducer 114 may be in electrical communication with the generator 102 , for example, via a cable 122 (e.g., a multi-conductor cable).
  • the transducer 114 may comprise piezoceramic elements, or other elements or components suitable for converting the electrical energy of a drive signal into mechanical vibrations.
  • the ultrasonic transducer 114 When activated by the generator 102 , the ultrasonic transducer 114 may cause longitudinal vibration.
  • the vibration may be transmitted through an instrument portion 124 of the device 104 (e.g., via a waveguide embedded in an outer sheath) to an end effector 126 of the instrument portion 124 .
  • FIG. 3 illustrates one embodiment of the end effector 126 of the example ultrasonic device 104 .
  • the end effector 126 may comprise a blade 151 that may be coupled to the ultrasonic transducer 114 via the wave guide (not shown). When driven by the transducer 114 , the blade 151 may vibrate and, when brought into contact with tissue, may cut and/or coagulate the tissue, as described herein.
  • the end effector 126 may also comprise a clamp arm 155 that may be configured for cooperative action with the blade 151 of the end effector 126 . With the blade 151 , the clamp arm 155 may comprise a set of jaws 140 .
  • the clamp arm 155 may be pivotally connected at a distal end of a shaft 153 of the instrument portion 124 .
  • the clamp arm 155 may include a clamp arm tissue pad 163 , which may be formed from TEFLON® or other suitable low-friction material.
  • the pad 163 may be mounted for cooperation with the blade 151 , with pivotal movement of the clamp arm 155 positioning the clamp pad 163 in substantially parallel relationship to, and in contact with, the blade 151 .
  • a tissue bite to be clamped may be grasped between the tissue pad 163 and the blade 151 .
  • the tissue pad 163 may be provided with a saw-tooth-like configuration including a plurality of axially spaced, proximally extending gripping teeth 161 to enhance the gripping of tissue in cooperation with the blade 151 .
  • the clamp arm 155 may transition from the open position shown in FIG. 3 to a closed position (with the clamp arm 155 in contact with or proximity to the blade 151 ) in any suitable manner.
  • the hand piece 116 may comprise a jaw closure trigger 138 . When actuated by a clinician, the jaw closure trigger 138 may pivot the clamp arm 155 in any suitable manner.
  • the generator 102 may be activated to provide the drive signal to the transducer 114 in any suitable manner.
  • the generator 102 may comprise a foot switch 120 coupled to the generator 102 via a footswitch cable 122 ( FIG. 8 ).
  • a clinician may activate the transducer 114 , and thereby the transducer 114 and blade 151 , by depressing the foot switch 120 .
  • some embodiments of the device 104 may utilize one or more switches positioned on the hand piece 116 that, when activated, may cause the generator 102 to activate the transducer 114 .
  • the one or more switches may comprise a pair of toggle buttons 136 a, 136 b, for example, to determine an operating mode of the device 104 .
  • the toggle button 136 a When the toggle button 136 a is depressed, for example, the ultrasonic generator 102 may provide a maximum drive signal to the transducer 114 , causing it to produce maximum ultrasonic energy output. Depressing toggle button 136 b may cause the ultrasonic generator 102 to provide a user-selectable drive signal to the transducer 114 , causing it to produce less than the maximum ultrasonic energy output.
  • the device 104 additionally or alternatively may comprise a second switch to, for example, indicate a position of a jaw closure trigger 138 for operating jaws 140 of the end effector 126 .
  • the ultrasonic generator 102 may be activated based on the position of the jaw closure trigger 138 , (e.g., as the clinician depresses the jaw closure trigger 138 to close the jaws 140 , ultrasonic energy may be applied.
  • the one or more switches may comprises a toggle button 136 c that, when depressed, causes the generator 102 to provide a pulsed output.
  • the pulses may be provided at any suitable frequency and grouping, for example.
  • the power level of the pulses may be the power levels associated with toggle buttons 136 a, b (maximum, less than maximum), for example.
  • a device 104 may comprise any combination of the toggle buttons 136 a, b, c.
  • the device 104 could be configured to have only two toggle buttons: a toggle button 136 a for producing maximum ultrasonic energy output and a toggle button 136 c for producing a pulsed output at either the maximum or less than maximum power level per.
  • the drive signal output configuration of the generator 102 could be 5 continuous signals and 5 or 4 or 3 or 2 or 1 pulsed signals.
  • the specific drive signal configuration may be controlled based upon, for example, EEPROM settings in the generator 102 and/or user power level selection(s).
  • a two-position switch may be provided as an alternative to a toggle button 136 c.
  • a device 104 may include a toggle button 136 a for producing a continuous output at a maximum power level and a two-position toggle button 136 b. In a first detented position, toggle button 136 b may produce a continuous output at a less than maximum power level, and in a second detented position the toggle button 136 b may produce a pulsed output (e.g., at either a maximum or less than maximum power level, depending upon the EEPROM settings).
  • the end effector 126 may also comprise a pair of electrodes 159 , 157 .
  • the electrodes 159 , 157 may be in communication with the generator 102 , for example, via the cable 122 .
  • the electrodes 159 , 157 may be used, for example, to measure an impedance of a tissue bite present between the clamp arm 155 and the blade 151 .
  • the generator 102 may provide a signal (e.g., a non-therapeutic signal) to the electrodes 159 , 157 .
  • the impedance of the tissue bite may be found, for example, by monitoring the current, voltage, etc. of the signal.
  • FIG. 4 illustrates one embodiment of an example electrosurgical device 106 that may also be used for transection and sealing.
  • the transection and sealing device 106 may comprise a hand piece assembly 130 , a shaft 165 and an end effector 132 .
  • the shaft 165 may be rigid (e.g., for laparoscopic and/or open surgical application) or flexible, as shown, (e.g., for endoscopic application).
  • the shaft 165 may comprise one or more articulation points.
  • the end effector 132 may comprise jaws 144 having a first jaw member 167 and a second jaw member 169 .
  • the first jaw member 167 and second jaw member 169 may be connected to a clevis 171 , which, in turn, may be coupled to the shaft 165 .
  • a translating member 173 may extend within the shaft 165 from the end effector 132 to the hand piece 130 .
  • the shaft 165 may be directly or indirectly coupled to a jaw closure trigger 142 ( FIG. 4 ).
  • the jaw members 167 , 169 of the end effector 132 may comprise respective electrodes 177 , 179 .
  • the electrodes 177 , 179 may be connected to the generator 102 via electrical leads 187 a, 187 b ( FIG. 5 ) extending from the end effector 132 through the shaft 165 and handpiece 130 and ultimately to the generator 102 (e.g., by a multiconductor cable 128 ).
  • the generator 102 may provide a drive signal to the electrodes 177 , 179 to bring about a therapeutic effect to tissue present within the jaw members 167 , 169 .
  • the electrodes 177 , 179 may comprise an active electrode and a return electrode, wherein the active electrode and the return electrode can be positioned against, or adjacent to, the tissue to be treated such that current can flow from the active electrode to the return electrode through the tissue.
  • the end effector 132 is shown with the jaw members 167 , 169 in an open position.
  • a reciprocating blade 175 is illustrated between the jaw members 167 , 169 .
  • FIGS. 5, 6 and 7 illustrate one embodiment of the end effector 132 shown in FIG. 4 .
  • a clinician may cause the jaw closure trigger 142 to pivot along arrow 183 from a first position to a second position. This may cause the jaws 144 to open and close according to any suitable method.
  • motion of the jaw closure trigger 142 may, in turn, cause the translating member 173 to translate within a bore 185 of the shaft 165 .
  • a distal portion of the translating member 173 may be coupled to a reciprocating member 197 such that distal and proximal motion of the translating member 173 causes corresponding distal and proximal motion of the reciprocating member.
  • the reciprocating member 197 may have shoulder portions 191 a, 191 b, while the jaw members 167 , 169 may have corresponding cam surfaces 189 a, 189 b. As the reciprocating member 197 is translated distally from the position shown in FIG. 6 to the position shown in FIG. 7 , the shoulder portions 191 a, 191 b may contact the cam surfaces 189 a, 189 b, causing the jaw members 167 , 169 to transition to the closed position. Also, in various embodiments, the blade 175 may be positioned at a distal end of the reciprocating member 197 . As the reciprocating member extends to the fully distal position shown in FIG.
  • the blade 175 may be pushed through any tissue present between the jaw members 167 , 169 , in the process, severing it.
  • a clinician may place the end effector 132 and close the jaws 144 around a tissue bite to be acted upon, for example, by pivoting the jaw closure trigger 142 along arrow 183 as described.
  • the clinician may initiate the provision of RF or other electro-surgical energy by the generator 102 and through the electrodes 177 , 179 .
  • the provision of RF energy may be accomplished in any suitable way.
  • the clinician may activate the foot switch 120 ( FIG. 8 ) of the generator 102 to initiate the provision of RF energy.
  • the hand piece 130 may comprise one or more switches 181 that may be actuated by the clinician to cause the generator 102 to begin providing RF energy.
  • RF energy may be provided based on the position of the jaw closure trigger 142 . For example, when the trigger 142 is fully depressed (indicating that the jaws 144 are closed), RF energy may be provided.
  • the blade 175 may be advanced during closure of the jaws 144 or may be separately advanced by the clinician after closure of the jaws 144 (e.g., after a RF energy has been applied to the tissue).
  • FIG. 8 is a diagram of the surgical system 100 of FIG. 1 .
  • the generator 102 may comprise several separate functional elements, such as modules and/or blocks. Different functional elements or modules may be configured for driving the different kinds of surgical devices 104 , 106 .
  • an ultrasonic generator module 108 may drive an ultrasonic device, such as the ultrasonic device 104 .
  • An electrosurgery/RF generator module 110 may drive the electrosurgical device 106 .
  • the respective modules 108 , 110 may generate respective drive signals for driving the surgical devices 104 , 106 .
  • the ultrasonic generator module 108 and/or the electrosurgery/RF generator module 110 each may be formed integrally with the generator 102 .
  • one or more of the modules 108 , 110 may be provided as a separate circuit module electrically coupled to the generator 102 .
  • the modules 108 and 110 are shown in phantom to illustrate this option.
  • the electrosurgery/RF generator module 110 may be formed integrally with the ultrasonic generator module 108 , or vice versa.
  • the ultrasonic generator module 108 may produce a drive signal or signals of particular voltages, currents, and frequencies, e.g. 55,500 cycles per second (Hz).
  • the drive signal or signals may be provided to the ultrasonic device 104 , and specifically to the transducer 114 , which may operate, for example, as described above.
  • the generator 102 may be configured to produce a drive signal of a particular voltage, current, and/or frequency output signal that can be stepped with high resolution, accuracy, and repeatability.
  • the electrosurgery/RF generator module 110 may generate a drive signal or signals with output power sufficient to perform bipolar electrosurgery using radio frequency (RF) energy.
  • RF radio frequency
  • the drive signal may be provided, for example, to the electrodes 177 , 179 of the electrosurgical device 106 , for example, as described above.
  • the generator 102 may be configured for therapeutic purposes by applying electrical energy to the tissue sufficient for treating the tissue (e.g., coagulation, cauterization, tissue welding, etc.).
  • the generator 102 may comprise an input device 145 ( FIG. 1 ) located, for example, on a front panel of the generator 102 console.
  • the input device 145 may comprise any suitable device that generates signals suitable for programming the operation of the generator 102 . In operation, the user can program or otherwise control operation of the generator 102 using the input device 145 .
  • the input device 145 may comprise any suitable device that generates signals that can be used by the generator (e.g., by one or more processors contained in the generator) to control the operation of the generator 102 (e.g., operation of the ultrasonic generator module 108 and/or electrosurgery/RF generator module 110 ).
  • the input device 145 includes one or more of buttons, switches, thumbwheels, keyboard, keypad, touch screen monitor, pointing device, remote connection to a general purpose or dedicated computer.
  • the input device 145 may comprise a suitable user interface, such as one or more user interface screens displayed on a touch screen monitor, for example. Accordingly, by way of the input device 145 , the user can set or program various operating parameters of the generator, such as, for example, current (I), voltage (V), frequency (f), and/or period (T) of a drive signal or signals generated by the ultrasonic generator module 108 and/or electrosurgery/RF generator module 110 .
  • the generator 102 may also comprise an output device 147 ( FIG. 1 ) located, for example, on a front panel of the generator 102 console.
  • the output device 147 includes one or more devices for providing a sensory feedback to a user.
  • Such devices may comprise, for example, visual feedback devices (e.g., an LCD display screen, LED indicators), audio feedback devices (e.g., a speaker, a buzzer) or tactile feedback devices (e.g., haptic actuators).
  • modules and/or blocks of the generator 102 may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used and still fall within the scope of the embodiments.
  • various embodiments may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components, e.g., processors, Digital Signal Processors (DSPs), Programmable Logic Devices (PLDs), Application Specific Integrated Circuits (ASICs), circuits, registers and/or software components, e.g., programs, subroutines, logic and/or combinations of hardware and software components.
  • DSPs Digital Signal Processors
  • PLDs Programmable Logic Devices
  • ASICs Application Specific Integrated Circuits
  • the ultrasonic generator drive module 108 and electrosurgery/RF drive module 110 may comprise one or more embedded applications implemented as firmware, software, hardware, or any combination thereof.
  • the modules 108 , 110 may comprise various executable modules such as software, programs, data, drivers. application program interfaces (APIs), and so forth.
  • the firmware may be stored in nonvolatile memory (NVM), such as in bit-masked read-only memory (ROM) or flash memory. In various implementations, storing the firmware in ROM may preserve flash memory.
  • the NVM may comprise other types of memory including, for example, programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or battery backed random-access memory (RAM) such as dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), and/or synchronous DRAM (SDRAM).
  • PROM programmable ROM
  • EPROM erasable programmable ROM
  • EEPROM electrically erasable programmable ROM
  • RAM battery backed random-access memory
  • DRAM dynamic RAM
  • DDRAM Double-Data-Rate DRAM
  • SDRAM synchronous DRAM
  • the modules 108 , 110 comprise a hardware component implemented as a processor for executing program instructions for monitoring various measurable characteristics of the devices 104 , 106 and generating a corresponding output drive signal or signals for operating the devices 104 , 106 .
  • the drive signal may drive the ultrasonic transducer 114 in cutting and/or coagulation operating modes. Electrical characteristics of the device 104 and/or tissue may be measured and used to control operational aspects of the generator 102 and/or provided as feedback to the user.
  • the drive signal may supply electrical energy (e.g., RF energy) to the end effector 132 in cutting, coagulation and/or desiccation modes. Electrical characteristics of the device 106 and/or tissue may be measured and used to control operational aspects of the generator 102 and/or provided as feedback to the user.
  • the hardware components may be implemented as DSP, PLD, ASIC, circuits, and/or registers.
  • the processor may be configured to store and execute computer software program instructions to generate the step function output signals for driving various components of the devices 104 , 106 , such as the ultrasonic transducer 114 and the end effectors 126 , 132 .
  • FIG. 9 illustrates an equivalent circuit 150 of an ultrasonic transducer, such as the ultrasonic transducer 114 , according to one embodiment.
  • the circuit 150 comprises a first “motional” branch having a serially connected inductance L s , resistance R s and capacitance C s that define the electromechanical properties of the resonator, and a second capacitive branch having a static capacitance C 0 .
  • Drive current I g may be received from a generator at a drive voltage V g , with motional current I m flowing through the first branch and current I g ⁇ I m flowing through the capacitive branch.
  • Control of the electromechanical properties of the ultrasonic transducer may be achieved by suitably controlling I g and V g .
  • known generator architectures may include a tuning inductor L t (shown in phantom in FIG. 9 ) for tuning out in a parallel resonance circuit the static capacitance C 0 at a resonant frequency so that substantially all of generator's current output I g flows through the motional branch. In this way, control of the motional branch current I m is achieved by controlling the generator current output I g .
  • the tuning inductor L t is specific to the static capacitance C 0 of an ultrasonic transducer, however, and a different ultrasonic transducer having a different static capacitance requires a different tuning inductor L t .
  • the tuning inductor L t is matched to the nominal value of the static capacitance C 0 at a single resonant frequency, accurate control of the motional branch current I m is assured only at that frequency, and as frequency shifts down with transducer temperature, accurate control of the motional branch current is compromised.
  • the generator 102 may not rely on a tuning inductor L t to monitor the motional branch current I m . Instead, the generator 102 may use the measured value of the static capacitance C 0 in between applications of power for a specific ultrasonic surgical device 104 (along with drive signal voltage and current feedback data) to determine values of the motional branch current I m on a dynamic and ongoing basis (e.g., in real-time). Such embodiments of the generator 102 are therefore able to provide virtual tuning to simulate a system that is tuned or resonant with any value of static capacitance C 0 at any frequency, and not just at a single resonant frequency dictated by a nominal value of the static capacitance C 0 .
  • FIG. 10 is a simplified block diagram of one embodiment of the generator 102 for proving inductorless tuning as described above, among other benefits.
  • FIGS. 11A-11C illustrate an architecture of the generator 102 of FIG. 10 according to one embodiment.
  • the generator 102 may comprise a patient isolated stage 152 in communication with a non-isolated stage 154 via a power transformer 156 .
  • a secondary winding 158 of the power transformer 156 is contained in the isolated stage 152 and may comprise a tapped configuration (e.g., a center-tapped or non-center tapped configuration) to define drive signal outputs 160 a, 160 b, 160 c for outputting drive signals to different surgical devices, such as, for example, an ultrasonic surgical device 104 and an electrosurgical device 106 .
  • drive signal outputs 160 a, 160 c may output a drive signal (e.g., a 420V RMS drive signal) to an ultrasonic surgical device 104
  • drive signal outputs 160 b, 160 c may output a drive signal (e.g., a 100V RMS drive signal) to an electrosurgical device 106 , with output 160 b corresponding to the center tap of the power transformer 156
  • the non-isolated stage 154 may comprise a power amplifier 162 having an output connected to a primary winding 164 of the power transformer 156 .
  • the power amplifier 162 may comprise a push-pull amplifier, for example.
  • the non-isolated stage 154 may further comprise a programmable logic device 166 for supplying a digital output to a digital-to-analog converter (DAC) 168 , which in turn supplies a corresponding analog signal to an input of the power amplifier 162 .
  • the programmable logic device 166 may comprise a field-programmable gate array (FPGA), for example.
  • FPGA field-programmable gate array
  • the programmable logic device 166 by virtue of controlling the power amplifier's 162 input via the DAC 168 , may therefore control any of a number of parameters (e.g., frequency, waveform shape, waveform amplitude) of drive signals appearing at the drive signal outputs 160 a, 160 b, 160 c.
  • the programmable logic device 166 in conjunction with a processor (e.g., processor 174 discussed below), may implement a number of digital signal processing (DSP)-based and/or other control algorithms to control parameters of the drive signals output by the generator 102 .
  • DSP digital signal processing
  • Power may be supplied to a power rail of the power amplifier 162 by a switch-mode regulator 170 .
  • the switch-mode regulator 170 may comprise an adjustable buck regulator, for example.
  • the non-isolated stage 154 may further comprise a processor 174 . which in one embodiment may comprise a DSP processor such as an Analog Devices ADSP-21469 SHARC DSP, available from Analog Devices, Norwood, Mass., for example.
  • the processor 174 may control operation of the switch-mode power converter 170 responsive to voltage feedback data received from the power amplifier 162 by the processor 174 via an analog-to-digital converter (ADC) 176 .
  • ADC analog-to-digital converter
  • the processor 174 may receive as input, via the ADC 176 , the waveform envelope of a signal (e.g., an RF signal) being amplified by the power amplifier 162 .
  • the processor 174 may then control the switch-mode regulator 170 (e.g., via a pulse-width modulated (PWM) output) such that the rail voltage supplied to the power amplifier 162 tracks the waveform envelope of the amplified signal.
  • PWM pulse-width modulated
  • the programmable logic device 166 may implement a direct digital synthesizer (DDS) control scheme to control the waveform shape, frequency and/or amplitude of drive signals output by the generator 102 .
  • DDS direct digital synthesizer
  • the programmable logic device 166 may implement a DDS control algorithm 268 by recalling waveform samples stored in a dynamically-updated look-up table (LUT), such as a RAM LUT which may be embedded in an FPGA.
  • LUT dynamically-updated look-up table
  • This control algorithm is particularly useful for ultrasonic applications in which an ultrasonic transducer, such as the ultrasonic transducer 114 , may be driven by a clean sinusoidal current at its resonant frequency. Because other frequencies may excite parasitic resonances, minimizing or reducing the total distortion of the motional branch current may correspondingly minimize or reduce undesirable resonance effects.
  • voltage and current feedback data based on the drive signal may be input into an algorithm, such as an error control algorithm implemented by the processor 174 , which compensates for distortion by suitably pre-distorting or modifying the waveform samples stored in the LUT on a dynamic, ongoing basis (e.g., in real-time).
  • the amount or degree of pre-distortion applied to the LUT samples may be based on the error between a computed motional branch current and a desired current waveform shape, with the error being determined on a sample-by sample basis.
  • the pre-distorted LUT samples when processed through the drive circuit, may result in a motional branch drive signal having the desired waveform shape (e.g., sinusoidal) for optimally driving the ultrasonic transducer.
  • the LUT waveform samples will therefore not represent the desired waveform shape of the drive signal, but rather the waveform shape that is required to ultimately produce the desired waveform shape of the motional branch drive signal when distortion effects are taken into account.
  • the non-isolated stage 154 may further comprise an ADC 178 and an ADC 180 coupled to the output of the power transformer 156 via respective isolation transformers 182 , 184 for respectively sampling the voltage and current of drive signals output by the generator 102 .
  • the ADCs 178 , 180 may be configured to sample at high speeds (e.g., 80 Msps) to enable oversampling of the drive signals. In one embodiment, for example, the sampling speed of the ADCs 178 , 180 may enable approximately 200 ⁇ (depending on drive frequency) oversampling of the drive signals.
  • the sampling operations of the ADCs 178 , 180 may be performed by a single ADC receiving input voltage and current signals via a two-way multiplexer.
  • Voltage and current feedback data output by the ADCs 178 , 180 may be received and processed (e.g., FIFO buffering, multiplexing) by the programmable logic device 166 and stored in data memory for subsequent retrieval by, for example, the processor 174 .
  • voltage and current feedback data may be used as input to an algorithm for pre-distorting or modifying LUT waveform samples on a dynamic and ongoing basis.
  • this may require each stored voltage and current feedback data pair to be indexed based on, or otherwise associated with, a corresponding LUT sample that was output by the programmable logic device 166 when the voltage and current feedback data pair was acquired. Synchronization of the LUT samples and the voltage and current feedback data in this manner contributes to the correct timing and stability of the pre-distortion algorithm.
  • the voltage and current feedback data may be used to control the frequency and/or amplitude (e.g., current amplitude) of the drive signals.
  • voltage and current feedback data may be used to determine impedance phase.
  • the frequency of the drive signal may then be controlled to minimize or reduce the difference between the determined impedance phase and an impedance phase setpoint (e.g., 0°), thereby minimizing or reducing the effects of harmonic distortion and correspondingly enhancing impedance phase measurement accuracy.
  • the determination of phase impedance and a frequency control signal may be implemented in the processor 174 , for example, with the frequency control signal being supplied as input to a DDS control algorithm implemented by the programmable logic device 166 .
  • the current feedback data may be monitored in order to maintain the current amplitude of the drive signal at a current amplitude setpoint.
  • the current amplitude setpoint may be specified directly or determined indirectly based on specified voltage amplitude and power setpoints.
  • control of the current amplitude may be implemented by control algorithm, such as, for example, a proportional-integral-derivative (PID) control algorithm, in the processor 174 .
  • PID proportional-integral-derivative
  • Variables controlled by the control algorithm to suitably control the current amplitude of the drive signal may include, for example, the scaling of the LUT waveform samples stored in the programmable logic device 166 and/or the full-scale output voltage of the DAC 168 (which supplies the input to the power amplifier 162 ) via a DAC 186 .
  • the non-isolated stage 154 may further comprise a processor 190 for providing, among other things user interface (UI) functionality.
  • the processor 190 may comprise an Atmel AT91 SAM9263 processor having an ARM 926EJ-S core, available from Atmel Corporation, San Jose, Calif., for example.
  • Examples of UI functionality supported by the processor 190 may include audible and visual user feedback, communication with peripheral devices (e.g., via a Universal Serial Bus (USB) interface), communication with the footswitch 120 , communication with an input device 112 (e.g., a touch screen display) and communication with an output device 147 (e.g., a speaker).
  • USB Universal Serial Bus
  • the processor 190 may communicate with the processor 174 and the programmable logic device (e.g., via serial peripheral interface (SPI) buses). Although the processor 190 may primarily support UI functionality, it may also coordinate with the processor 174 to implement hazard mitigation in certain embodiments. For example, the processor 190 may be programmed to monitor various aspects of user input and/or other inputs (e.g., touch screen inputs, footswitch 120 inputs, temperature sensor inputs) and may disable the drive output of the generator 102 when an erroneous condition is detected.
  • SPI serial peripheral interface
  • both the processor 174 and the processor 190 may determine and monitor the operating state of the generator 102 .
  • the operating state of the generator 102 may dictate, for example, which control and/or diagnostic processes are implemented by the processor 174 .
  • the operating state of the generator 102 may dictate, for example, which elements of a user interface (e.g., display screens, sounds) are presented to a user.
  • the processors 174 , 190 may independently maintain the current operating state of the generator 102 and recognize and evaluate possible transitions out of the current operating state.
  • the processor 174 may function as the master in this relationship and determine when transitions between operating states are to occur.
  • the processor 190 may be aware of valid transitions between operating states and may confirm if a particular transition is appropriate. For example, when the processor 174 instructs the processor 190 to transition to a specific state, the processor 190 may verify that requested transition is valid. In the event that a requested transition between states is determined to be invalid by the processor 190 , the processor 190 may cause the generator 102 to enter a failure mode.
  • the non-isolated stage 154 may further comprise a controller 196 for monitoring input devices 145 (e.g., a capacitive touch sensor used for turning the generator 102 on and off, a capacitive touch screen).
  • the controller 196 may comprise at least one processor and/or other controller device in communication with the processor 190 .
  • the controller 196 may comprise a processor (e.g., a Mega168 8-bit controller available from Atmel) configured to monitor user input provided via one or more capacitive touch sensors.
  • the controller 196 may comprise a touch screen controller (e.g., a QT5480 touch screen controller available from Atmel) to control and manage the acquisition of touch data from a capacitive touch screen.
  • the controller 196 may continue to receive operating power (e.g., via a line from a power supply of the generator 102 , such as the power supply 211 discussed below). In this way, the controller 196 may continue to monitor an input device 145 (e.g., a capacitive touch sensor located on a front panel of the generator 102 ) for turning the generator 102 on and off.
  • an input device 145 e.g., a capacitive touch sensor located on a front panel of the generator 102
  • the controller 196 may wake the power supply (e.g., enable operation of one or more DC/DC voltage converters 213 of the power supply 211 ) if activation of the “on/off” input device 145 by a user is detected.
  • the controller 196 may therefore initiate a sequence for transitioning the generator 102 to a “power on” state. Conversely, the controller 196 may initiate a sequence for transitioning the generator 102 to the power off state if activation of the “on/off” input device 145 is detected when the generator 102 is in the power on state. In certain embodiments, for example, the controller 196 may report activation of the “on/off” input device 145 to the processor 190 , which in turn implements the necessary process sequence for transitioning the generator 102 to the power off state. In such embodiments, the controller 196 may have no independent ability for causing the removal of power from the generator 102 after its power on state has been established.
  • the controller 196 may cause the generator 102 to provide audible or other sensory feedback for alerting the user that a power on or power off sequence has been initiated. Such an alert may be provided at the beginning of a power on or power off sequence and prior to the commencement of other processes associated with the sequence.
  • the isolated stage 152 may comprise an instrument interface circuit 198 to, for example, provide a communication interface between a control circuit of a surgical device (e.g., a control circuit comprising handpiece switches) and components of the non-isolated stage 154 , such as, for example, the programmable logic device 166 , the processor 174 and/or the processor 190 .
  • the instrument interface circuit 198 may exchange information with components of the non-isolated stage 154 via a communication link that maintains a suitable degree of electrical isolation between the stages 152 , 154 , such as, for example, an infrared (IR)-based communication link.
  • Power may be supplied to the instrument interface circuit 198 using, for example, a low-dropout voltage regulator powered by an isolation transformer driven from the non-isolated stage 154 .
  • the instrument interface circuit 198 may comprise a programmable logic device 200 (e.g., an FPGA) in communication with a signal conditioning circuit 202 .
  • the signal conditioning circuit 202 may be configured to receive a periodic signal from the programmable logic device 200 (e.g., a 2 kHz square wave) to generate a bipolar interrogation signal having an identical frequency.
  • the interrogation signal may be generated, for example, using a bipolar current source fed by a differential amplifier.
  • the interrogation signal may be communicated to a surgical device control circuit (e.g., by using a conductive pair in a cable that connects the generator 102 to the surgical device) and monitored to determine a state or configuration of the control circuit. As discussed below in connection with FIGS.
  • the control circuit may comprise a number of switches, resistors and/or diodes to modify one or more characteristics (e.g., amplitude, rectification) of the interrogation signal such that a state or configuration of the control circuit is uniquely discernable based on the one or more characteristics.
  • the signal conditioning circuit 202 may comprise an ADC for generating samples of a voltage signal appearing across inputs of the control circuit resulting from passage of interrogation signal therethrough. The programmable logic device 200 (or a component of the non-isolated stage 154 ) may then determine the state or configuration of the control circuit based on the ADC samples.
  • the instrument interface circuit 198 may comprise a first data circuit interface 204 to enable information exchange between the programmable logic device 200 (or other element of the instrument interface circuit 198 ) and a first data circuit disposed in or otherwise associated with a surgical device.
  • a first data circuit 206 may be disposed in a cable integrally attached to a surgical device handpiece, or in an adaptor for interfacing a specific surgical device type or model with the generator 102 .
  • the first data circuit may comprise a non-volatile storage device, such as an electrically erasable programmable read-only memory (EEPROM) device.
  • EEPROM electrically erasable programmable read-only memory
  • the first data circuit interface 204 may be implemented separately from the programmable logic device 200 and comprise suitable circuitry (e.g., discrete logic devices, a processor) to enable communication between the programmable logic device 200 and the first data circuit. In other embodiments, the first data circuit interface 204 may be integral with the programmable logic device 200 .
  • the first data circuit 206 may store information pertaining to the particular surgical device with which it is associated. Such information may include, for example, a model number, a serial number, a number of operations in which the surgical device has been used, and/or any other type of information. This information may be read by the instrument interface circuit 198 (e.g., by the programmable logic device 200 ), transferred to a component of the non-isolated stage 154 (e.g., to programmable logic device 166 , processor 174 and/or processor 190 ) for presentation to a user via an output device 147 and/or for controlling a function or operation of the generator 102 .
  • the instrument interface circuit 198 e.g., by the programmable logic device 200
  • a component of the non-isolated stage 154 e.g., to programmable logic device 166 , processor 174 and/or processor 190
  • any type of information may be communicated to first data circuit 206 for storage therein via the first data circuit interface 204 (e.g., using the programmable logic device 200 ).
  • Such information may comprise, for example, an updated number of operations in which the surgical device has been used and/or dates and/or times of its usage.
  • a surgical instrument may be detachable from a handpiece (e.g., instrument 124 may be detachable from handpiece 116 ) to promote instrument interchangeability and/or disposability.
  • known generators may be limited in their ability to recognize particular instrument configurations being used and to optimize control and diagnostic processes accordingly.
  • the addition of readable data circuits to surgical device instruments to address this issue is problematic from a compatibility standpoint, however. For example, designing a surgical device to remain backwardly compatible with generators that lack the requisite data reading functionality may be impractical due to, for example, differing signal schemes, design complexity and cost.
  • Embodiments of instruments discussed below in connection with FIGS. 16-32 address these concerns by using data circuits that may be implemented in existing surgical instruments economically and with minimal design changes to preserve compatibility of the surgical devices with current generator platforms.
  • embodiments of the generator 102 may enable communication with instrument-based data circuits, such as those described below in connection with FIGS. 16-32 and FIGS. 33A-33C .
  • the generator 102 may be configured to communicate with a second data circuit (e.g., data circuit 284 of FIG. 16 ) contained in an instrument (e.g., instrument 124 or 134 ) of a surgical device.
  • the instrument interface circuit 198 may comprise a second data circuit interface 210 to enable this communication.
  • the second data circuit interface 210 may comprise a tri-state digital interface, although other interfaces may also be used.
  • the second data circuit may generally be any circuit for transmitting and/or receiving data.
  • the second data circuit may store information pertaining to the particular surgical instrument with which it is associated. Such information may include, for example, a model number, a serial number, a number of operations in which the surgical instrument has been used, and/or any other type of information. Additionally or alternatively, any type of information may be communicated to second data circuit for storage therein via the second data circuit interface 210 (e.g., using the programmable logic device 200 ). Such information may comprise, for example, an updated number of operations in which the instrument has been used and/or dates and/or times of its usage.
  • the second data circuit may transmit data acquired by one or more sensors (e.g., an instrument-based temperature sensor).
  • the second data circuit may receive data from the generator 102 and provide an indication to a user (e.g., an LED indication or other visible indication) based on the received data.
  • the second data circuit and the second data circuit interface 210 may be configured such that communication between the programmable logic device 200 and the second data circuit can be effected without the need to provide additional conductors for this purpose (e.g., dedicated conductors of a cable connecting a handpiece to the generator 102 ).
  • information may be communicated to and from the second data circuit using a one-wire bus communication scheme implemented on existing cabling, such as one of the conductors used transmit interrogation signals from the signal conditioning circuit 202 to a control circuit in a handpiece. In this way, design changes or modifications to the surgical device that might otherwise be necessary are minimized or reduced.
  • the isolated stage 152 may comprise at least one blocking capacitor 296 - 1 connected to the drive signal output 160 b to prevent passage of DC current to a patient.
  • a single blocking capacitor may be required to comply with medical regulations or standards, for example. While failure in single-capacitor designs is relatively uncommon, such failure may nonetheless have negative consequences.
  • a second blocking capacitor 296 - 2 may be provided in series with the blocking capacitor 296 - 1 , with current leakage from a point between the blocking capacitors 296 - 1 , 296 - 2 being monitored by, for example, an ADC 298 for sampling a voltage induced by leakage current. The samples may be received by the programmable logic device 200 , for example.
  • the generator 102 may determine when at least one of the blocking capacitors 296 - 1 , 296 - 2 has failed. Accordingly, the embodiment of FIG. 10 may provide a benefit over single-capacitor designs having a single point of failure.
  • the non-isolated stage 154 may comprise a power supply 211 for outputting DC power at a suitable voltage and current.
  • the power supply may comprise, for example, a 400 W power supply for outputting a 48 VDC system voltage.
  • the power supply 211 may further comprise one or more DC/DC voltage converters 213 for receiving the output of the power supply to generate DC outputs at the voltages and currents required by the various components of the generator 102 .
  • one or more of the DC/DC voltage converters 213 may receive an input from the controller 196 when activation of the “on/off” input device 145 by a user is detected by the controller 196 to enable operation of, or wake, the DC/DC voltage converters 213 .
  • FIGS. 13A-13B illustrate certain functional and structural aspects of one embodiment of the generator 102 .
  • Feedback indicating current and voltage output from the secondary winding 158 of the power transformer 156 is received by the ADCs 178 , 180 , respectively.
  • the ADCs 178 , 180 may be implemented as a 2-channel ADC and may sample the feedback signals at a high speed (e.g., 80 Msps) to enable oversampling (e.g., approximately 200 ⁇ oversampling) of the drive signals.
  • the current and voltage feedback signals may be suitably conditioned in the analog domain (e.g., amplified, filtered) prior to processing by the ADCs 178 , 180 .
  • the programmable logic device 166 comprises an FPGA.
  • the multiplexed current and voltage feedback samples may be received by a parallel data acquisition port (PDAP) implemented within block 214 of the processor 174 .
  • the PDAP may comprise a packing unit for implementing any of a number of methodologies for correlating the multiplexed feedback samples with a memory address.
  • feedback samples corresponding to a particular LUT sample output by the programmable logic device 166 may be stored at one or more memory addresses that are correlated or indexed with the LUT address of the LUT sample.
  • feedback samples corresponding to a particular LUT sample output by the programmable logic device 166 may be stored, along with the LUT address of the LUT sample, at a common memory location.
  • the feedback samples may be stored such that the address of an LUT sample from which a particular set of feedback samples originated may be subsequently ascertained. As discussed above, synchronization of the LUT sample addresses and the feedback samples in this way contributes to the correct timing and stability of the pre-distortion algorithm.
  • a direct memory access (DMA) controller implemented at block 216 of the processor 174 may store the feedback samples (and any LUT sample address data, where applicable) at a designated memory location 218 of the processor 174 (e.g., internal RAM).
  • Block 220 of the processor 174 may implement a pre-distortion algorithm for pre-distorting or modifying the LUT samples stored in the programmable logic device 166 on a dynamic, ongoing basis.
  • pre-distortion of the LUT samples may compensate for various sources of distortion present in the output drive circuit of the generator 102 .
  • the pre-distorted LUT samples, when processed through the drive circuit, will therefore result in a drive signal having the desired waveform shape (e.g., sinusoidal) for optimally driving the ultrasonic transducer.
  • the current through the motional branch of the ultrasonic transducer is determined.
  • the motional branch current may be determined using Kirchoff's Current Law based on, for example, the current and voltage feedback samples stored at memory location 218 (which, when suitably scaled, may be representative of I g and V g in the model of FIG. 9 discussed above), a value of the ultrasonic transducer static capacitance C 0 (measured or known a priori) and a known value of the drive frequency.
  • a motional branch current sample for each set of stored current and voltage feedback samples associated with a LUT sample may be determined.
  • each motional branch current sample determined at block 222 is compared to a sample of a desired current waveform shape to determine a difference, or sample amplitude error, between the compared samples.
  • the sample of the desired current waveform shape may be supplied, for example, from a waveform shape LUT 226 containing amplitude samples for one cycle of a desired current waveform shape.
  • the particular sample of the desired current waveform shape from the LUT 226 used for the comparison may be dictated by the LUT sample address associated with the motional branch current sample used in the comparison. Accordingly, the input of the motional branch current to block 224 may be synchronized with the input of its associated LUT sample address to block 224 .
  • the LUT samples stored in the programmable logic device 166 and the LUT samples stored in the waveform shape LUT 226 may therefore be equal in number.
  • the desired current waveform shape represented by the LUT samples stored in the waveform shape LUT 226 may be a fundamental sine wave.
  • Other waveform shapes may be desirable. For example, it is contemplated that a fundamental sine wave for driving main longitudinal motion of an ultrasonic transducer superimposed with one or more other drive signals at other frequencies, such as a third order harmonic for driving at least two mechanical resonances for beneficial vibrations of transverse or other modes, could be used.
  • Each value of the sample amplitude error determined at block 224 may be transmitted to the LUT of the programmable logic device 166 (shown at block 228 in FIG. 13A ) along with an indication of its associated LUT address. Based on the value of the sample amplitude error and its associated address (and, optionally, values of sample amplitude error for the same LUT address previously received), the LUT 228 (or other control block of the programmable logic device 166 ) may pre-distort or modify the value of the LUT sample stored at the LUT address such that the sample amplitude error is reduced or minimized.
  • Current and voltage amplitude measurements, power measurements and impedance measurements may be determined at block 230 of the processor 174 based on the current and voltage feedback samples stored at memory location 218 .
  • the feedback samples may be suitably scaled and, in certain embodiments, processed through a suitable filter 232 to remove noise resulting from, for example, the data acquisition process and induced harmonic components.
  • the filtered voltage and current samples may therefore substantially represent the fundamental frequency of the generator's drive output signal.
  • the filter 232 may be a finite impulse response (FIR) filter applied in the frequency domain.
  • FFT fast Fourier transform
  • the resulting frequency spectrum may be used to provide additional generator functionality.
  • the ratio of the second and/or third order harmonic component relative to the fundamental frequency component may be used as a diagnostic indicator.
  • a root mean square (RMS) calculation may be applied to a sample size of the current feedback samples representing an integral number of cycles of the drive signal to generate a measurement I rms representing the drive signal output current.
  • RMS root mean square
  • a root mean square (RMS) calculation may be applied to a sample size of the voltage feedback samples representing an integral number of cycles of the drive signal to determine a measurement V rms representing the drive signal output voltage.
  • RMS root mean square
  • the current and voltage feedback samples may be multiplied point by point, and a mean calculation is applied to samples representing an integral number of cycles of the drive signal to determine a measurement P r of the generator's real output power.
  • measurement P a of the generator's apparent output power may be determined as the product V rms ⁇ I rms .
  • measurement Z m of the load impedance magnitude may be determined as the quotient V rms /I rms .
  • the quantities I rms , V rms , P r , P a and Z m determined at blocks 234 , 236 , 238 , 240 and 242 may be used by the generator 102 to implement any of number of control and/or diagnostic processes.
  • any of these quantities may be communicated to a user via, for example, an output device 147 integral with the generator 102 or an output device 147 connected to the generator 102 through a suitable communication interface (e.g., a USB interface).
  • Various diagnostic processes may include, without limitation, handpiece integrity, instrument integrity, instrument attachment integrity, instrument overload, approaching instrument overload, frequency lock failure, over-voltage, over-current, over-power, voltage sense failure, current sense failure, audio indication failure, visual indication failure, short circuit, power delivery failure, blocking capacitor failure, for example.
  • Block 244 of the processor 174 may implement a phase control algorithm for determining and controlling the impedance phase of an electrical load (e.g., the ultrasonic transducer) driven by the generator 102 .
  • an electrical load e.g., the ultrasonic transducer
  • Block 244 of the processor 174 may implement a phase control algorithm for determining and controlling the impedance phase of an electrical load (e.g., the ultrasonic transducer) driven by the generator 102 .
  • an impedance phase setpoint e.g., 0°
  • the phase control algorithm receives as input the current and voltage feedback samples stored in the memory location 218 .
  • the feedback samples may be suitably scaled and, in certain embodiments, processed through a suitable filter 246 (which may be identical to filter 232 ) to remove noise resulting from the data acquisition process and induced harmonic components, for example.
  • the filtered voltage and current samples may therefore substantially represent the fundamental frequency of the generator's drive output signal.
  • the current through the motional branch of the ultrasonic transducer is determined. This determination may be identical to that described above in connection with block 222 of the pre-distortion algorithm.
  • the output of block 248 may thus be, for each set of stored current and voltage feedback samples associated with a LUT sample, a motional branch current sample.
  • impedance phase is determined based on the synchronized input of motional branch current samples determined at block 248 and corresponding voltage feedback samples.
  • the impedance phase is determined as the average of the impedance phase measured at the rising edge of the waveforms and the impedance phase measured at the falling edge of the waveforms.
  • the value of the impedance phase determined at block 222 is compared to phase setpoint 254 to determine a difference, or phase error, between the compared values.
  • a frequency output for controlling the frequency of the drive signal is determined.
  • the value of the frequency output may be continuously adjusted by the block 256 and transferred to a DDS control block 268 (discussed below) in order to maintain the impedance phase determined at block 250 at the phase setpoint (e.g., zero phase error).
  • the impedance phase may be regulated to a 0° phase setpoint. In this way, any harmonic distortion will be centered about the crest of the voltage waveform, enhancing the accuracy of phase impedance determination.
  • Block 258 of the processor 174 may implement an algorithm for modulating the current amplitude of the drive signal in order to control the drive signal current, voltage and power in accordance with user specified setpoints, or in accordance with requirements specified by other processes or algorithms implemented by the generator 102 . Control of these quantities may be realized, for example, by scaling the LUT samples in the LUT 228 and/or by adjusting the full-scale output voltage of the DAC 168 (which supplies the input to the power amplifier 162 ) via a DAC 186 .
  • Block 260 (which may be implemented as a PID controller in certain embodiments) may receive as input current feedback samples (which may be suitably scaled and filtered) from the memory location 218 .
  • the current feedback samples may be compared to a “current demand” I d value dictated by the controlled variable (e.g., current, voltage or power) to determine if the drive signal is supplying the necessary current.
  • the current demand I d may be specified directly by a current setpoint 262 A (I sp ).
  • an RMS value of the current feedback data (determined as in block 234 ) may be compared to user-specified RMS current setpoint I sp to determine the appropriate controller action.
  • LUT scaling and/or the full-scale output voltage of the DAC 168 may be adjusted by the block 260 such that the drive signal current is increased. Conversely, block 260 may adjust LUT scaling and/or the full-scale output voltage of the DAC 168 to decrease the drive signal current when the current feedback data indicates an RMS value greater than the current setpoint I sp .
  • Block 268 may implement a DDS control algorithm for controlling the drive signal by recalling LUT samples stored in the LUT 228 .
  • the DDS control algorithm be a numerically-controlled oscillator (NCO) algorithm for generating samples of a waveform at a fixed clock rate using a point (memory location)-skipping technique.
  • the NCO algorithm may implement a phase accumulator, or frequency-to-phase converter, that functions as an address pointer for recalling LUT samples from the LUT 228 .
  • the phase accumulator may be a D step size, modulo N phase accumulator, where D is a positive integer representing a frequency control value, and N is the number of LUT samples in the LUT 228 .
  • the phase accumulator may skip addresses in the LUT 228 , resulting in a waveform output having a higher frequency.
  • the frequency of the waveform generated by the DDS control algorithm may therefore be controlled by suitably varying the frequency control value.
  • the frequency control value may be determined based on the output of the phase control algorithm implemented at block 244 .
  • the output of block 268 may supply the input of DAC 168 , which in turn supplies a corresponding analog signal to an input of the power amplifier 162 .
  • Block 270 of the processor 174 may implement a switch-mode converter control algorithm for dynamically modulating the rail voltage of the power amplifier 162 based on the waveform envelope of the signal being amplified, thereby improving the efficiency of the power amplifier 162 .
  • characteristics of the waveform envelope may be determined by monitoring one or more signals contained in the power amplifier 162 .
  • characteristics of the waveform envelope may be determined by monitoring the minima of a drain voltage (e.g., a MOSFET drain voltage) that is modulated in accordance with the envelope of the amplified signal.
  • a minima voltage signal may be generated, for example, by a voltage minima detector coupled to the drain voltage.
  • the minima voltage signal may be sampled by ADC 176 , with the output minima voltage samples being received at block 272 of the switch-mode converter control algorithm. Based on the values of the minima voltage samples, block 274 may control a PWM signal output by a PWM generator 276 , which, in turn, controls the rail voltage supplied to the power amplifier 162 by the switch-mode regulator 170 . In certain embodiments, as long as the values of the minima voltage samples are less than a minima target 278 input into block 262 , the rail voltage may be modulated in accordance with the waveform envelope as characterized by the minima voltage samples.
  • block 274 may cause a low rail voltage to be supplied to the power amplifier 162 , with the full rail voltage being supplied only when the minima voltage samples indicate maximum envelope power levels.
  • block 274 may cause the rail voltage to be maintained at a minimum value suitable for ensuring proper operation of the power amplifier 162 .
  • FIGS. 33A-33C illustrate control circuits of surgical devices according to various embodiments.
  • a control circuit may modify characteristics of an interrogation signal transmitted by the generator 102 .
  • the characteristics of the interrogation signal which may uniquely indicate a state or configuration of the control circuit, can be discerned by the generator 102 and used to control aspects of its operation.
  • the control circuits may be contained in an ultrasonic surgical device (e.g., in the handpiece 116 of the ultrasonic surgical device 104 ), or in an electrosurgical device (e.g., in the handpiece 130 of the electrosurgical device 106 ).
  • a control circuit 300 - 1 may be connected to the generator 102 to receive an interrogation signal (e.g., a bipolar interrogation signal at 2 kHz) from the signal conditioning circuit 202 (e.g., from generator terminals HS and SR ( FIG. 10 ) via a conductive pair of cable 112 or cable 128 ).
  • the control circuit 300 - 1 may comprise a first branch that includes series-connected diodes D 1 and D 2 and a switch SW 1 connected in parallel with D 2 .
  • the control circuit 300 - 1 may also comprise a second branch that includes series-connected diodes D 3 , D 4 and D 5 , a switch SW 2 connected in parallel with D 4 , and a resistor R 1 connected in parallel with D 5 .
  • D 5 may be a Zener diode.
  • the control circuit 300 - 1 may additionally comprise a data storage element 302 that, together with one or more components of the second branch (e.g., D 5 , R 1 ), define a data circuit 304 .
  • the data storage element 302 may be contained in the instrument (e.g., instrument 124 , instrument 134 ) of the surgical device, with other components of the control circuit 300 - 1 (e.g., SW 1 , SW 2 , D 1 , D 2 , D 3 , D 4 ) being contained in the handpiece (e.g., handpiece 116 , handpiece 130 ).
  • the data storage element 302 may be a single-wire bus device (e.g., a single-wire protocol EEPROM), or other single-wire protocol or local interconnect network (LIN) protocol device.
  • the data storage element 302 may comprise a Maxim DS28EC20 EEPROM, available from Maxim Integrated Products, Inc., Sunnyvale, Calif., known under the trade name “1-Wire.”
  • the data storage element 302 is one example of a circuit element that may be contained in the data circuit 304 .
  • the data circuit 304 may additionally or alternatively comprise one or more other circuit elements or components capable of transmitting or receiving data.
  • Such circuit elements or components may be configured to, for example, transmit data acquired by one or more sensors (e.g., an instrument-based temperature sensor) and/or receive data from the generator 102 and provide an indication to a user (e.g., an LED indication or other visible indication) based on the received data.
  • an interrogation signal (e.g., a bipolar interrogation signal at 2 kHz) from the signal conditioning circuit 202 may be applied across both branches of the control circuit 300 - 1 .
  • the voltage appearing across the branches may be uniquely determined by the states of SW 1 and SW 2 .
  • SW 1 when SW 1 is open, the voltage drop across the control circuit 300 - 1 for negative values of the interrogation signal will be sum of the forward voltage drops across D 1 and D 2 .
  • SW 1 is closed, the voltage drop for negative values of the interrogation signal will be determined by the forward voltage drop of D 1 only.
  • open and closed states of SW 1 may correspond to voltage drops of 1.4 volts and 0.7 volts, respectively.
  • the voltage drop across the control circuit 300 - 1 for positive values of the interrogation signal may be uniquely determined by the state of SW 2 .
  • the voltage drop across the control circuit 300 - 1 will be the sum of the forward voltage drops across D 3 and D 4 (e.g., 1.4 volts) and the breakdown voltage of D 5 (e.g., 3.3 volts).
  • the voltage drop across the control circuit 300 - 1 will be the sum of the forward voltage drop across D 3 and the breakdown voltage of D 5 . Accordingly, the state or configuration of SW 1 and SW 2 may be discerned by the generator 102 based on the interrogation signal voltage appearing across the inputs of the control circuit 300 - 1 (e.g., as measured by an ADC of the signal conditioning circuit 202 ).
  • the generator 102 may be configured to communicate with the data circuit 304 , and, in particular, with the data storage element 302 , via the second data circuit interface 210 ( FIG. 10 ) and the conductive pair of cable 112 or cable 128 .
  • the frequency band of the communication protocol used to communicate with the data circuit 304 may be higher than the frequency band of the interrogation signal.
  • the frequency of the communication protocol for the data storage element 302 may be, for example, 200 kHz or a significantly higher frequency
  • the frequency of the interrogation signal used to determine the different states of SW 1 and SW 2 may be, for example, 2 kHz.
  • Diode D 5 may limit the voltage supplied to the data storage element 302 to a suitable operating range (e.g., 3.3-5V).