WO2011146498A2 - Configurable pulse generator - Google Patents

Abstract

Disclosed are devices, systems, and methods, including a device that includes a dynamically configurable pulse generator to generate one or more electrical pulses with one or more adjustable attributes, the one or more pulses to be applied to a load (e.g., cardiac tissue) through electrodes. The configurable pulse generator is operable to be reconfigured after generating at least one of the one or more pulses. The device also includes a controller to dynamically configure the pulse generator to generate the one or more electrical pulses. The device may further include at least one sensor to measure at least one characteristic (e.g., impedance) associated with the load (e.g., the cardiac tissue of a patient). The pulse generator may be adapted to generate the one or more pulses with the attributes determined based, at least in part, on the measured at least one characteristic associated with the load.

Description

CONFIGURABLE PULSE GENERATOR

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 61/395,588, filed on May 17, 2010 and entitled "A Flexible Reconfigurable High Voltage Pulse Generator for Cardiac Stimulation and/or Defibrillation," the disclosure of which is incorporated herein by reference in its entirety.

FIELD

[0002] Systems, methods and devices for a pulse generator that delivers one or more short and/or high-voltage pulses or pulse trains to a load, e.g., pulse train delivered to the heart for cardiac stimulation, are described herein. Pulse generator embodiments of the present disclosure may include one or more Marx generators having a plurality of capacitors, switches and other electrical components dynamically configurable to provide customized pulse generation.

BACKGROUND

[0003] High- voltage ("HV") pulse generators are known in the art. One type of HV pulse generator, known as a "Marx Generator," contains a plurality of capacitors that may be charged in parallel and discharged in, for example, a series configuration to generate HV pulses having voltages greater than the voltage of the power supply of the pulse generator. Among the numerous possible applications for HV pulse generators is the generation of defibrillation pulses for treating ventricular fibrillation ("VF") and/or atrial fibrillation ("AF"). AF is the most common cardiac arrhythmia and involves at least one of the upper chambers of the heart, such as the right atrium or the left atrium. One way to defibrillate the atrium is to deliver electrical defibrillation pulses to the heart at specific times during the cardiac cycle.

[0004] Systems and devices for delivering HV defibrillation pulses may be external to, and/or implanted within, the body of a patient. Atrial defibrillation ("ADF") using an implantable atrial defibrillator generally includes automated detection of AF and automated delivery of an electrical pulse to the left and/or right atrium of the heart. Delivering an electrical pulse however may be intolerably painful for a patient and, thus, may discourage the use of automatic implantable atrial defibrillators. While delivering an electrical pulse having an energy that is too high may cause pain to a patient, delivering, on the other hand, an electrical pulse having an energy that is too low will result in an unsuccessful defibrillation attempt. Accordingly, ADF that is tolerable, effective and/or reduces the discomfort to a patient may be desired.

SUMMARY

[0005] The current example embodiments of the present disclosure provide a configurable, fiexible HV pulse generator to facilitate, for example, cardiac stimulation such as defibrillation, in which one, some or all of parameters, including number of pulses in a train, pulse duration of each pulse, voltage and/or energy in each pulse, time interval between pulses (when more than one pulse exist in the train), polarity of each pulse, etc., may be dynamically selected and controlled. In some embodiments, the pulse generator may be reconfigured (e.g., change internal electrical paths using switches, after delivering at least one of the pulses in the train).

[0006] In some embodiments, the parameters of a train of pulses having one or more pulses are determined before the train of pulses commences. In some embodiments, the parameters of a train of pulses are determined or updated in response to measured characteristics (e.g., impedance of the load) prior to the application of the train.

[0007] In some embodiments, train parameters may be changed or selected in response to measurements performed during application of the train. In some variations, pulse duration may be shortened or lengthened based on voltage, energy, and/or current measurements performed during application of pulse train. In some embodiments, measurement(s) performed during one pulse affects the selection of parameters of the following pulse or pulses. In some embodiments, pulse duration may be shortened or lengthened based on voltage, energy, and/or current measurements performed during said pulse. In some embodiments, measurement(s) performed during one pulse affects the selection of parameters of the same pulse.

[0008] Additionally and/or optionally, the capacitance associated with each pulse may be controlled, leading to controllable "tilt" (voltage drop during the pulse). Additionally and optionally, the capacitance associated with each pulse may be selected to vary during a pulse train, leading to controllable inconstant pulse tilt. For example, through controllable configuration of the switches of the pulse generator, the capacitance can be controlled so that a desired pulse tilt is obtained for the generated pulses.

[0009] One possible application of the pulse generator according to the current disclosure is to provide a high voltage pulse or a train of pulses for heart defibrillation such as atrial or ventricle defibrillation.

[0010] According to an example embodiment of the disclosure, the HV pulse generator is used in an Atrial and/or Ventricular defibrillator device. The device may be external or implanted or may be external with a lead or leads and electrodes inserted into the patient's body. In some embodiments, the defibrillator using the example HV pulse generator causes minimum discomfort to the patient due to the unique properties of the pulse trains delivered to the heart by the pulse generator, as described, for example, in the PCT Application number PCT/US2009/033786 entitled "Atrial Defibrillation Using Short Pulses," filed on February 11, 2009, the content of which is hereby incorporated by reference in its entirety.

[0011] In some implementations, a high voltage pulse generator capable of delivering a single or multiple HV short pulses is provided. The pulse generator includes, in some embodiment, a flexible Marx generator including a plurality of capacitors and a plurality of HV diodes and controlled switches that act to controllably and flexibly combine the capacitors in variety of parallel and serial arrangements/configurations. Optionally, in some embodiments, the generator includes a configurable main Marx generator that enables configuring delivery of voltage pulses at a coarse resolution (e.g., at increments of 400V), and/or a configurable fine tune Marx generator (which may be part of the main Marx generator) that enable setting the voltage of the pulses to be delivered at a finer resolution (e.g., at increments of 50V). The output voltage delivered to the load may then be the sum of the controllable voltages produced by, for example, the configurable main Marx generator and the configurable fine tune Marx generator. In some embodiments, the usage of the generators is controllable. The output voltage may be either the output of one of the generators, or it can be the sum of the two outputs, depending on the configuration of the switches.

[0012] In some embodiments, impedance sensing is provided for measuring the load impedance before the pulse train. Current, voltage and power sensors are configured to sense the pulse in real time. The generator may be controlled by a controller which may be configured (e.g., pre-programmed) to respond to the measurements of the real time sensors. The generator may be used for cardiac defibrillation. Optional waveforms used for defibrillation may be provided.

[0013] Thus, in some embodiments, a cardiac treatment device is disclosed. The device includes a dynamically configurable pulse generator to generate one or more electrical pulses with one or more adjustable attributes, the one or more electrical pulses to be applied to target cardiac tissue of a patient through electrodes. The dynamically configurable pulse generator is operable to be reconfigured after generating at least one of the one or more electrical pulses. The device also includes a controller to dynamically configure the pulse generator to generate the one or more electrical pulses with the one or more adjustable attributes.

[0014] Embodiments of the method may include any of the features described in the present disclosure, as well as any one or more of the following features.

[0015] The one more electrical pulses may include a pulse train with each of the pulses in the train associated with a corresponding set of attributes. The pulse generator may be adapted to be reconfigured after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated.

[0016] The pulse generator may include a Marx generator including a plurality of capacitors configured to be controllably charged with current from an energy source, and to be adjustably electrically coupled to the electrodes in accordance with signals generated by the controller adapted to dynamically configure the Marx generator to generate the one or more electrical pulses.

[0017] At least some of the plurality of capacitors may be charged before a first of the one or more electrical pulses is generated. The energy source may be electrically uncoupled from the plurality of capacitors until a last of the one or more electrical pulses has been generated.

[0018] The Marx generator may further include one or more switches controllable by the controller, the one or more switches facilitating selectively establishing electrical paths between at least some of the plurality of capacitors and the electrodes. The one or more switches may include at least one insulated gate bipolar transistor (IGBT) switch. The one or more switches may include at least one polarity switch to reverse voltage polarity of at least one of the one or more electrical pulses generated by the Marx generator. The one or more switches may include at least one crowbar switch to perform a fast discharge of the plurality of capacitors of the Marx generator.

[0019] The device may further include one or more diodes to block electrical discharge not directed to the target cardiac tissue.

[0020] The Marx generator may include a configurable fine tune Marx generator with fine tune capacitors configured to be arranged to produce a plurality of possible voltage levels in a first range, and a configurable main Marx generator with main capacitors configured to be arranged to produce a plurality of possible incremental voltage levels that are each separated by a value of at least the first range.

[0021] An initial voltage level of the Marx generator available for delivery of pulses may be equal to a sum of a voltage from the first range produced by the fine tune Marx generator and a voltage produced by the main Marx generator.

[0022] The plurality of capacitors configured to be controllably charged with current from an energy source, and to be adjustably electrically coupled to the electrodes, may include at least a first capacitor controllably coupled in a parallel arrangement to at least another first capacitor, and at least a second capacitor controllably coupled in a series arrangement to at least another second capacitor.

[0023] The device may further include two or more electrode-pairs, with the pulse generator being configured to generate a pulse train comprising a plurality of pulses, with at least one of the plurality of pulses delivered through one of the two or more electrode-pairs, and at least another of the plurality of pulses delivered through another of the two or more electrode pairs, the plurality of pulses being delivered without having to recharge the plurality of capacitors.

[0024] The Marx generator may be configured for fast charging of at least one of the plurality of capacitors using one or more of a switch and a diode to implement charging resistance electrically coupled to the at least one of the plurality of capacitors.

[0025] At least some of the capacitors may be arranged to enable at least one of the generated one or more pulses to have a varying tilt.

[0026] The device may further include a feedback monitor including at least one generator sensor to measure values of electrical characteristics of one or more of, for example, the one or more generated electrical pulses, and/or electrical characteristics in at least one location of electrical paths established in the dynamically configured pulse generator. The controller to dynamically configure the pulse generator may be adapted to configure the pulse generator based on the values of the electrical characteristics measured by the at least one generator sensor of the feedback monitor.

[0027] The device may further include a main switch configured to be opened to terminate the flow of the one or more pulses in response to a comparison of the values of the electrical characteristics measured by the at least one generator sensor and respective one or more predetermined threshold values.

[0028] The device may further include at least one sensor to measure at least one characteristic associated with the target cardiac tissue of the patient. The pulse generator may be adapted to generate the one or more electrical pulses with the one or more attributes determined based, at least in part, on the measured at least one characteristic associated with the target cardiac tissue.

[0029] The at least one sensor to measure the at least one characteristic associated with the target cardiac tissue of the patient may be configured to measure electrical impedance of the target cardiac tissue.

[0030] The at least one sensor configured to measure the electrical impedance of the target cardiac tissue may be configured to determine the electrical impedance of the target cardiac tissue substantially in real-time by dividing data representative of a measured realtime voltage applied to the target cardiac tissue by data representative of a measured realtime current applied to the target cardiac tissue.

[0031] The pulse generator may further be configured to terminate the one or more pulses based, at least in part, on the determined substantially real-time electrical impedance.

[0032] The device may further include an impedance measurement relay to disconnect the at least one sensor configured to measure the electrical impedance of the target cardiac tissue from a circuitry through which the generated one or more pulses are delivered.

[0033] The controller may be adapted to dynamically configure the pulse generator to generate the one or more pulses with the one or more attributes determined based, at least in part, on the measured electrical impedance of the target cardiac tissue. [0034] The one or more attributes of the one more electrical pulses to be generated may include one or more of, for example, initial voltage of the one or more pulses, end voltage of the one or more pulses, voltage tilt of the one or more pulses representative of a difference between the initial voltage and the end voltage of the one or more pulses as a percentage of the initial voltage, pulse duration of the one or more pulses, and/or interval between pulses in the one or more pulses.

[0035] The pulse generator may be configured to terminate delivery of the one or more pulses in response to one or more of, for example, sensing over current condition, sensing that pulse current is too low, sensing over voltage condition, sensing that pulse voltage is too low, sensing that the pulse voltage is decaying too fast, sensing that the pulse voltage is decaying too slowly, and/or sensing unusual energy reading.

[0036] In some embodiments, a method is disclosed. The method includes determining one or more attributes associated with one or more electrical pulses to be applied to target cardiac tissue of a patient through electrodes, and configuring a dynamically configurable pulse generator to generate the one or more electrical pulses with the determined one or more attributes, the dynamically configurable pulse generator being operable to be reconfigured after generating at least one of the one or more electrical pulses.

[0037] Embodiments of the method may include any of the features described in the present disclosure, including any of the features described above in relation to the device, as well as any one or more of the following features.

[0038] The one more electrical pulses may include a pulse train with each of the pulses in the train associated with a corresponding set of attributes, and configuring the pulse generator may include reconfiguring the pulse generator after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated.

[0039] Configuring the pulse generator to generate the one or more electrical pulses with the determined one or more attributes may include configuring a Marx generator including a plurality of capacitors configured to be controllably charged, and to be adjustably electrically coupled to the electrodes, to generate the one or more electrical pulses.

[0040] Configuring the Marx generator may include configuring at least one of the one or more switches to one of open and close positions to selectively establish electrical paths between at least some of the plurality of capacitors and the electrodes. [0041] The method may further include measuring at least one characteristic associated with the target cardiac tissue of the patient. Determining the one or more attributes associated with the one or more electrical pulses may include determining the one or more attributes based, at least in part, on the measured at least one characteristic.

[0042] Measuring the at least one characteristic associated with the target cardiac tissue of the patient may include measuring electrical impedance of the target cardiac tissue.

[0043] Determining the one or more attributes may include determining the one or more attributes based, at least in part, on the measured electrical impedance of the target cardiac tissue.

[0044] In some embodiments, a system is disclosed. The system includes a dynamically configurable pulse generator to generate one or more electrical pulses with determined one or more adjustable attributes, the one or more electrical pulses to be applied to target cardiac tissue of a patient through electrodes. The dynamically configurable pulse generator is operable to be reconfigured after generating at least one of the one or more electrical pulses. The system also includes an energy source coupled to the pulse generator to power and charge the pulse generator, and a controller to dynamically configure the pulse generator to generate the one or more electrical pulses with the determined one or more attributes.

[0045] Embodiments of the system may include any of the features described in the present disclosure, including any of the features described above in relation to the device and the method.

[0046] In some embodiments, a device is disclosed. The device includes a dynamically configurable pulse generator to generate one or more electrical pulses with one or more adjustable attributes, the one or more electrical pulses to be applied to a load through electrodes. The dynamically configurable pulse generator is operable to be reconfigured after generating at least one of the one or more electrical pulses. The device also includes a controller to dynamically configure the pulse generator to generate the one or more electrical pulses with the one or more adjustable attributes.

[0047] Embodiments of the device may include any of the features described in the present disclosure, including any of the features described above in relation to the first device, the method, and the system.

[0048] The details of one or more variations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features and advantages of the subject matter described herein will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Fig. la shows a block diagram of an example pulse generator according to some embodiments of the present disclosure.

[0050] Fig. lb shows an electrical circuit diagram of an example pulse generator according to some embodiments of the present disclosure.

[0051] Fig. lc schematically indicates some of the components used in the electrical circuit diagram of a configurable pulse generator in accordance with some embodiments of the present disclosure.

[0052] Fig. 2 shows an electrical circuit diagram of an example embodiment of a power supply unit (section) used for charging capacitors of a pulse generator according to some embodiments of the present disclosure.

[0053] Fig. 3 shows an electrical circuit diagram of embodiments of example fine-tune and main Marx generators of a pulse generator according to some embodiments of the present disclosure.

[0054] Figs. 4a-4d show electrical circuit diagrams of examples fine-tune Marx generator configurations according to some embodiments of the present disclosure.

[0055] Fig. 4e is an electrical circuit diagram showing a fast discharge path for an example fine-tune Marx generator according to some embodiments of the present disclosure.

[0056] Figs. 5a-5g show example illustrations of various switch configurations of electrical circuit diagram of a main Marx generator according to some embodiments of the present disclosure.

[0057] Fig. 5h is an electrical circuit diagram showing a fast discharge path for an example main Marx generator according to some embodiments of the present disclosure.

[0058] Fig. 5i is an electrical circuit diagram of an example embodiment of a configurable main Marx generator that includes switches and diodes to implement charging resistance for at least some of the capacitors of the main Marx generator. [0059] Fig. 6 shows an example illustration of an electrical circuit diagram of an optically-driven HV switch of a pulse generator according to some embodiments of the present disclosure.

[0060] Fig. 7 shows an example illustration of an electrical circuit diagram of a discharge, main and polarity reversing switches section/unit of a pulse generator according to some embodiments of the present disclosure.

[0061] Fig. 8 shows an example illustration of an electrical circuit diagram of an impedance measuring, pulse sensing and defibrillation leads section (unit) of a pulse generator according to some embodiments of the present disclosure.

[0062] Fig. 9 shows an example illustration of an electrical circuit diagram of a controller of a pulse generator according to some embodiments of the present disclosure.

[0063] Fig. 10a shows an example equivalent electrical circuit diagram of a Marx generator, including capacitors Ci and C₂ connected in series (C₂>Ci) and including a blocking diode, during pulse discharge of a pulse generator, according to some embodiments of the present disclosure.

[0064] Fig. 10b shows an example pulse waveform with varying tilt generated by the equivalent electrical circuit depicted in Fig. 10a according to some embodiments of the present disclosure.

[0065] Figs. 11a and l ib show example first and second stages of the pulse path of a varying tilt pulse during the pulse discharge of the equivalent electrical circuit diagram of Fig. 10a according to some embodiments of the present disclosure.

[0066] Fig. 12a shows an example equivalent electrical circuit diagram of a main Marx generator, including capacitors Ci and C₂ in series with blocking diodes, during pulse discharge of a pulse generator according to some embodiments of the present disclosure.

[0067] Fig. 12b shows a pulse waveform with varying tilt generated by the equivalent electrical circuit depicted in Fig. 12a according to some embodiments of the present disclosure.

[0068] Figs. 13a and 13b show example first and second stages of the pulse path of a varying tilt pulse during the pulse discharge of the equivalent electrical circuit diagram of Fig. 12a according to some embodiments of the present disclosure. [0069] Figs. 14a-14d show pulse train waveforms generated by a pulse generator according to some embodiments of the present disclosure.

[0070] Fig. 15 shows a flowchart of an example procedure to configure a pulse generator for delivery of electrical pulses.

[0071] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0072] The subject matter of the present disclosure is not limited in its application to the details set forth in the following disclosure or in examples of the illustrative embodiments. The subject matter is capable of other embodiments or of being practiced or carried out in various ways.

[0073] Moreover, features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the present disclosure. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

[0074] Disclosed herein are devices, systems, and methods, including a device (e.g., a cardiac treatment devices) that includes a dynamically configurable pulse generator to generate one or more electrical pulses with one or more controllable/adjustable attributes, the one or more electrical pulses to be applied to target cardiac tissue of a patient through electrodes, the dynamically configurable pulse generator operable to be reconfigured after generating at least one of the one or more electrical pulses. The pulse generator (or a device including the pulse generator) may also include a controller to dynamically configure the pulse generator to generate the one or more electrical pulses with the one or more adjustable attributes. In some embodiments, the one or more electrical pulses include a pulse train with each of the pulses in the train associated with a corresponding set of attributes, and the pulse generator is adapted to be reconfigured after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated. In some embodiments, the pulse generator is a dynamically configurable Marx generator. In yet some further embodiments, the device (which may be the pulse generator itself) may include at least one sensor to measure at least one characteristic associated with the target load (e.g., cardiac tissue of a patient). In such embodiments, the pulse generator may be adapted to generate the one or more electrical pulses with one or more attributes that are determined based, at least in part, on the measured at least one characteristic associated with the load.

[0075] With reference to Fig. la, a block diagram of a pulse generator 100 (which may be part of a device, such as a cardiac treatment device) configurable for use in cardiac stimulation procedures according to some embodiments of the present disclosure is shown. The pulse generator 100 depicted in Fig. la is dynamically configured to generate various pulses and/or pulse train waveforms as needed to accommodate a wide spectrum of parameters associated with delivering, for example, appropriate atrial defibrillation ("ADF") pulses and/or ventricular defibrillation ("VDF") pulses to the heart. In some implementations, the dynamically configurable pulse generator 100 is adapted to be reconfigured after generating at least one of the one or more electrical pulses. Parameters such as voltage, duration, dwell time and pulse tilt may be dynamically changed according to embodiments of the present disclosure. For example, short-duration HV pulses, and/or pulse trains having one or more short-duration HV pulses with short dwell time between pulses, may be produced using embodiments of pulse generator 100. Such parameters may be selected before a pulse and/or pulse train delivery is initiated and/or such parameters may be changed during a pulse train delivery during the dwell time. For example, such parameters may be adjusted in response to measurements of properties (e.g., electrical characteristics) of the pulses of the train being delivered to the load and/or measurements of properties of various locations within the pulse generator 100 (e.g., voltage levels at various points in the internal circuitry of the pulse generator). As will be described in greater details below, in some embodiments, the initial determination of attributes of the pulse(s) to be delivered, and thus determination of the configuration of the pulse generator, may be based, at least in part, on at least one sensed/measured property of the load (e.g., the load's impedance, capacitance, etc.) In such embodiments, the measured at least one property of the load is used to determine the attributes of the pulses before the first pulse is delivered to the load. Termination of a pulse in a pulse train may also be dynamically set according to embodiments of the pulse generator 100 such that a pulse may be terminated, for example, when its accumulated charge or delivered energy has reached a preset value, when its voltage has dropped to a preset value or when the current of the pulse has surpassed a preset limit. The pulse generator 100 may be controlled, at least in part, by a controller 1 10, e.g., a controller implemented using a central processing unit ("CPU") for ease of use and flexible operation. The controller 1 10 may be part of the pulse generator, or may be a device separate from the pulse generator (e.g., may be situated at a remote location), and may thus establish a communication link with the pulse generator to communicate control signals and data to the pulse generator 100, including control signals to configure or reconfigure the pulse generator 100.

[0076] As further shown in Fig, la, the pulse generator 100 may be connected to a load 180 (e.g., the heart of a patient) to provide for the delivery of an HV pulse and/or pulse train to the load 180 via shock leads 182 (as also depicted in Fig. 8) including one or more electrodes coupled to the load 180. In some embodiments, the shock leads 182 may be connected to the pulse generator 100 at a connector 184 via one or more lead connectors (see Fig. 8).

[0077] As noted, in some embodiments, the pulse generator 100 may be controlled, at least in part, by the controller 1 10. In some embodiments, the controller 1 10 may include a CPU and/or a complex programmable logic device ("CPLD"). The controller 1 10 may also be configured to operate in connection with other systems and/or subsystems, such as a memory 1 1 1 , a clock 1 12, input devices 1 13 (e.g., a keyboard, mouse, and/or keypad) and/or an output device 1 14 (e.g., a display and/or indicators, such as light-emitting diodes, or LEDs). In some embodiments, the controller 1 10 may be connected to a computing device, such as a personal computer ("PC), a laptop computer, a personal digital assistance ("PDA") and/or a Smartphone to program the controller 1 10 and/or act as an input device 1 13 and/or output device 1 14. The controller 1 10 is configured to facilitate, for example, the controlling (e.g., configuring) the dynamically configurable pulse generator 100, e.g., by determining control signals to actuate switches (as will be described in greater details below) that establish a sequence of changing electrical paths to cause one or more pulses with determined associated attributes (e.g., voltage, duration, etc.) to be generated. In some implementations, the memory 1 1 1 may thus also include a computer program product comprising instructions that when executed on a processor-based controller, such as the controller 1 10, cause the processor-based controller to perform operations to control (configure) the dynamically configurable pulse generator 100.

[0078] The controller 1 10 may be connected to control lines 1 18 for controlling the operation of the pulse generator 100. In some embodiments, the controller 1 10 may receive data from sensors that detect/measure characteristics/parameters, such as load impedance, and/or pulse behavior data, such as pulse voltage, pulse current, pulse charge, pulse power and/or pulse discharge energy. The controller 110 may thus, in such embodiments, dynamically configure the pulse generator 110 based on the data representative of detected/measured characteristics/parameters.

[0079] Coupled to the pulse generator 100 is a power supply 130 that generates a charge voltage (V_c), for example, HV direct current ("DC") on two or more charging lines 132 of the pulse generator 100. In some implementations, the power supply may be disposed outside of a housing that houses the circuitry (modules/components) used to generate and deliver the one or more pulses to the load. The charging lines 132 may be in communication with a configurable fine tune Marx generator 140 and/or a configurable main Marx generator 150 of the pulse generator 100 and provide for the charging of one or more capacitors C„ (not shown in Fig. la) contained within the fine tune Marx generator 140 and/or main Marx generator 150. The term "Marx generator" as used herein refers to a type of electrical circuit that provide for the delivery of HV pulses by charging two or more capacitors C„ in parallel and discharging them in series.

[0080] The pulse generator 100 may also include a charging feedback circuit 120 connected to charging lines 132 which generates a signal indicative of the charging voltage (V_c) generated by the power supply 130. In some embodiments, the signal may be digitized by an analog-to-digital converter 124 ("ADC"). Data from the ADC may be used by the controller 110 to verify charging voltage V_c generated by the power supply 130 and used for charging the capacitors in the fine tune and/or main Marx generators 140 and 150. Before pulse generation occurs within the pulse generator 100, the power supply 130 may be, in some embodiments, disconnected from the fine tune Marx generator 140 and/or the main Marx generator 150 such that HV transients are isolated from the power supply 130. In embodiments of the present disclosure, the power supply 130 may generate a nominal charging voltage (V) (e.g., 400 V) that results in a much higher output voltage (e.g., 3,550 V) by, for example, serially connecting the capacitors of the fine tune Marx generator 140 and/or the main Marx generator 150.

[0081] During pulse creation, the voltage output by the fine tune Marx generator 140 and/or the main Marx generator 150 may be determined and/or preset by configuring one or more switches (e.g., IGBT switches, other types of transistor-based switches, electromechanical switches, etc.) within the Marx generators 140 and 150 (in embodiments of the pulse generators based on Marx generator implementations) which connect the capacitors in the Marx generators 140 and 150 to each other in parallel/series arrangements as a capacitor network. By varying which switches are opened and/or closed between different capacitors, the voltage output by the configurable fine tune Marx generator 140 and the configurable main Marx generator 150 may be customized to generate HV pulses and/or pulse trains of different desired voltages. As noted, the use of a fine tune Marx generator 140 enables achieving finer voltage resolution than can be obtained only by the main Marx generator 150. For example, the fine tune generator 140 includes controllably connectable capacitors to establish voltages that can be varied by a multiple of the smallest voltage that can be established using the various capacitors in the fine tune generator 140. In some embodiments, the position (i.e., open or closed) of the switches within the fine tune Marx generator 140 and the main Marx generator 150 may be controlled, at least in part, by the controller 110. For example, the controller 110 may generate control signals to actuate transistor-based switches to open or close those switches in order to connect the capacitors of the Marx generator 140 and/or the main Marx generator 150 to achieve the desired voltage level.

[0082] According to some embodiments, the voltage output by the configurable fine tune Marx generator 140 may be used to provide low- voltage ("LV") pulses when a high/low selector 136 is in an "open" state. In this configuration, the fine tune Marx may be connected through an LV bypass diode 138 to the load. In some embodiments, an HV pulse may be generated by adding the voltage output of the fine tune Marx generator 140 to the voltage output of the main Marx generator 150 by closing the high/low selector 136. The combined voltage of the Marx generators 140 and 150 may thus appear at the input of main, polarity and discharge switches section 160. The main switch of the main, polarity and discharge switches section 160 may be used for disconnecting the voltage output generated by the Marx generators 140 and 150 from the shock leads 182. The polarity switches of section 160 may be used to reverse the polarity of the voltage output generated by the Marx generators 140 and 150. The discharge switch (or crowbar switch) may be used to safely and rapidly discharge capacitors within the fine tune Marx generator 140 and/or main Marx generator 150 at the end of a pulse, pulse train and/or the operation of the pulse generator 100. In some embodiments, the discharge switch may be activated when an "abort" button is activated. The polarity switches may be controlled by the controller 110 and, in some embodiments, the main and discharge switches may be manually controlled to minimize risk due to controller error.

[0083] In some embodiments, the pulse generator 100 may include a current and voltage sensing section 170 that includes one or more real-time current and/or voltage sensors that monitor the current and voltage delivered to the load 180. Signals indicative of pulse voltage output by the Marx generators 140 and 150 may be multiplied, in some implementations, using a real-time multiplier 172 to generate a signal indicative of the power (P) delivered to the load 180. In some embodiments, analog accumulator or accumulators (not shown) may be used to generate signals indicative of accumulated delivered charge and energy by integrating the signal of the current and power, respectively. In some embodiments, threshold devices may create trigger signals when current, charge, voltage, power and/or energy exceeds a predetermined value. Thus, in some embodiments, the pulse generator 100 (or some other device that includes the pulse generator 100) may include a monitor that includes at least one generator sensor to measure values of electrical characteristics of one or more of, for example, the one or more electrical pulses generated by the pulse generator, and/or electrical characteristics in at least one location of electrical paths established in the dynamically configured pulse generator. A controller (such as the controller 110 depicted in Fig. la) may be adapted to configure the pulse generator based on the values of the electrical characteristics measured by the at least one generator sensor of the monitor. In such embodiments, a switch may be opened to terminate the flow of the one or more pulses in response to a comparison of the values of the electrical characteristics measured by the at least one generator sensor and respective one or more predetermined threshold values.

[0084] In some embodiments of the present disclosure, over current protection may be implemented to avoid risk of arcing or harm/damage to the load 180 when the shock leads 182 are shorted. According to some embodiments, a high-speed current sensor may be optionally used in conjunction with an analog threshold trigger, to initiate pulse termination and/or inhibition of subsequent pulses in a train. In some embodiments, a separate sensor may be used for the high-speed current sensing.

[0085] In some embodiments, the ADC 124 may digitize the signals indicative of current, voltage and/or power and the controller 110 may use one or more of these signals to dynamically determine/control pulse parameters or pulse train parameters, such as pulse duration and accumulated charge or energy, and to dynamically configure the configurable pulse generator based on such dynamically determined pulse or pulse train parameters. In some embodiments, a signal threshold determination, signal integration and/or scaling may be performed by, for example software implemented within the controller 110 and/or hardware implementation of at least some of the operations to determine parameter values and configure the configurable pulse generator.

[0086] According to some embodiments of the present disclosure, the lead connectors of the pulse generator 100 may be connected directly or indirectly to the main Marx generator 150 and/or the fine tune Marx generator 140, or to a load impedance sensing circuit 190 via a HV relay. The load impedance sensing circuit 190 may be used for determining the load alternating current ("AC") impedance, for example, at frequencies similar to the frequencies present in the pulse, but at low voltage.

[0087] In some embodiments, the pulse generator 100 (or a device including the pulse generator 100) may include a communication module 175 configured to interface (e.g., wirelessly or using wire-based link) with an external device using any type of a communication protocol (e.g., RS-232, Bluetooth, IEEE 802.11, etc.) The communication module 175 may be used for remotely controlling the pulse generator 100 (e.g., remotely determining/setting pulse parameters or operational parameters and/or triggering pulse generation), for receiving information from the pulse generator 100 (e.g., status, confirmation, actual measured pulse parameters). In some embodiments, a computer (e.g., a remote server, a PC or a laptop computer) connected to the controller 110 via the communication module 175 may be used to program the controller 100 for receiving measured pulse parameters, determining control signals to cause the pulse generator to be reconfigured based on those parameters, and perform any other operation in the course of controlling operation of the pulse generator 110. In some embodiments, the pulse or pulse train may be triggered by an electrocardiography ("ECG") monitoring unit (not shown) which may determine the necessity of one or more defibrillation pulses and/or synchronize the delivery of such pulses to the ECG cycle of a patient's heart.

[0088] Fig. lb shows an example electrical circuit diagram showing a possible implementation of at least part of the pulse generator 100 described with respect to Fig. la. Fig. lc schematically indicates some of the components used in the electrical circuit diagram of a configurable pulse generator in accordance with an example embodiment of the present disclosure of Fig. lb. Generally, components in figure lb are depicted using commonly used convention. Parts numbers, types, values are given in these figures for demonstration and/or clarification purpose and should not be viewed as limiting. [0089] Fig. 2 shows an electrical circuit diagram of an embodiment of a power supply section 200 used for charging capacitors (the capacitors are not depicted in Fig. 2) of a pulse generator according to some embodiments of the present disclosure. The power supply section 200 may include a power supply 230 in communication with one or more discharge resistors 210 and current limiting resistors 215 via charging lines 232. The discharge resistors 210 may ensure discharge of internal capacitors of the power supply 230. In some embodiments, the power supply section may be a floating high voltage zone.

[0090] The power supply 230 may also be in communication with a controller (such as the controller 110 of Fig. la) via a control line 218. To charge the capacitors, in some implementations, the power supply 230 may generate a voltage (e.g., 400 V) in response to a command or request sent along control line 218 from a controller of the pulse generator to the power supply 230. As the power supply 230 generates a voltage, the charging relays 260 may be closed to allow charge to flow along charging lines 232. In some embodiments, the charge relays 260 may be actuated to open or close them using control signals from a controller such as the controller 110 of Fig. la. The charging lines 232 may be denoted as having a positive (+) charge portion and a negative (-) charge. Current in the (+) and (-) charging lines 232 may be limited by the current limiting resistors 215. In some embodiments, the power supply section 200 may have an optical coupler 250 configured for sampling in an isolated manner the voltage along the charging lines 232. An ADC (not shown in Fig. 2) may be used to digitize the signal and relay it to the controller that uses the data to verify that the capacitors are/were charged to a desired voltage.

[0091] Before delivery of an HV pulse by the pulse generator is initiated, the charging relays 260 may be opened to disconnect, and thus protect, the power supply section 200 from transients flowing back along the charging lines 232. In some embodiments, activation of the pulse forming switches in the pulse generator (e.g., a Marx generator) may be disabled as long as the charging relays 260 are closed. After the power supply 230 generates a voltage and charges the capacitors in the pulse generator (e.g., in the configurable fine tune Marx generator and/or the configurable main Marx generator), the power supply 230 may be turned off and the voltage on the charge voltage sensor rapidly discharges. This decay may be monitored to ensure that the charging relays have indeed been opened.

[0092] According to some embodiments of the present disclosure, the power supply section 200 may be configured to work at ¼, ½, ¾ or full output voltage. Other fractions/percentages of the output voltages may also be implemented. For example, if full output voltage is 400 V, the voltage between the position (+) charging line 232 and the negative (-) charging line 232 may be selected to be 100, 200, 300 or 400V. In some embodiments, the position (+) charging line 232 and negative (-) charging line 232 may be floating with respect to actual ground. In some embodiments, the power supply section 200 may include more than one power supply (energy source) 230, individually controlled or controlled in groups, that may be connected in series such that their floating output voltages are summed.

[0093] Some embodiments of the power supply section 200 may include a charging feedback circuit that may include, or may be in electrical communication with, an ADC, a signal resistor 226 and a variable resistor 228, as shown in Fig. 2. The charging feedback circuit may function to generate a signal indicative of the charging voltage. In some embodiments, the charging voltage feedback circuit may be optically isolated from the rest of the circuit of the power supply section 200 by the optical coupler 250. In some embodiments, a trimming potentiometer 228 may be used for calibration.

[0094] Fig. 3 shows an electrical circuit diagram of an example embodiment of a configurable main Marx generator 350 and a configurable fine tune Marx generator 340 of a pulse generator according to some embodiments of the present disclosure. Prior to and/or during pulse creation, the output voltages of the fine tune Marx generator 340 and the main Marx generator 350 may be preset or dynamically determined, or altered by reconfiguring (i.e., opening or closing), one or more of the fine tune switches 300, 301 and 302 of the configurable fine tune Marx generator 340 and/or the switches 303, 304, 305, 306, 307, 308, 309 and 310 of the configurable main Marx generator to controllably establish electrical paths to enable a desired voltage on the capacitors to be reached, and consequently to generate the one or more pulses (pulse train) to be delivered to the load. In some implementations, the fine tune Marx generator may be connected in series to the main Marx generator, and the fine tune Marx generator may be configured to establish different series capacitor arrangements. In some implementations, the main Marx generator may be configured (through different switch configurations) to establish different serial/parallel capacitor arrangements. Thus, through the numerous possible configurations of opened and closed switch combinations, the pulse generator embodiments of the present disclosure provide for flexible and customized generation of HV and LV pulses of different desired voltages. In some embodiments, the switches may be controlled by a controller with or without human input or interaction, e.g., by having the controller generate control signal to actuate the switches of the fine tune and/or the main Marx generators

[0095] Figs. 4a-4d show electrical circuit diagrams of an embodiment of a fine tune Marx generator 400 and, in particular, various fine tune switches 410, 411, 412 and 413 and pulse current flow path configurations, according to the present disclosure. In these figures, the pulse current flow path may be established by the configuration of switches 410, 411 and 412 and is depicted in the figures as a thick line with a beginning marked as 420 and an ending marked 422. While alternative pulse current flow paths may exist, only one or a few have been depicted for sake of clarity in the figures. Some embodiments may also include one or more blocking diodes within the circuit, where one or more of such diodes may be reverse biased during parts of the operation of the circuit, thus channeling the pulse current along particular flow paths. For purposes of describing the embodiments illustrated in Figs. 4a-4e, a charging voltage of 400V has been used. However, the charging voltage may be any desired voltage and is not limited to this example.

[0096] The configurable fine tune Marx generator 400 may be configured as a modified version of Marx generator. The fine tune Marx generator 400 may include any number of capacitors. The embodiments depicted in Figs. 4a-4e each contain three capacitors (marked as CO, CI and C2 in Fig. 4a). Capacitors CO, CI and C2 may each be charged to any desired voltage, such as for example 50, 100 and 200 V, respectively. Charging the capacitors CO, CI and C2 may be performed through charging resistors connected to positive (+) and negative (-) charging lines 432. In some implementations, the charging resistors may be replaced with transistors and diodes so that, for example, charging time is reduced (because of lower charging resistance), and the charging circuit is more energy efficient, as less energy is dissipated by the charging resistors. For example, in some embodiments, the charging resistors on the (+) side of the charging lines may be replaced with diodes, while the charging resistors of (-) side of the charging lines may be replaced with switches (e.g., transistors). Furthermore, the use of diodes and transistors in place of charging resistors may enable the use of a current supply or power source supply (as opposed to using a voltage source) to thus increase the efficiency of the pulse generator. The use of a current source or a power source in conjunction with a pulse generator implemented with diode and transistors instead of charging resistors, may be of particular interest in relation implanted devices, where energy storage issues are of critical importance. [0097] Based on the example voltages above, if capacitors CO, CI and C2 are charged to 50, 100 and 200 V by a 400 V power supply, the total voltage on the capacitor chain would be 350 V. In some embodiments, correct voltage distribution may be maintained by 50, 100 and 200V Zener diodes 419.

[0098] In some embodiments, the capacitors CO, CI and C2 of the fine tune Marx generator 400 may be HV electrolytic capacitors having capacities of approximately 100 μΡ, 94 μΡ and 44 μΡ, respectively. In some embodiments, the capacitors CO, CI and C2 may be HV electrolytic capacitors having capacities of approximately 800 μΡ, 400 μΡ and 200 μΡ, respectively. The nominal charge on each of the main Marx generator capacitors is q = 400V * 40 μΡ = 16mQ. By choosing the values of capacitors CO, CI and C2, their charge is equal and 2.5 times that of the capacitors of the main Marx generator 470, as shown in the equation: 50V * 800 μΡ = 100V * 400 μΡ = 200V * 200 μΡ = 40mQ = 2.5q. Having the charge on capacitors of the fine tuning Marx generator 400 be 2.5 times the charge on the capacitors of the main Marx generator 470 ensures the ability to use the fine tuning Marx generator 400 for a pulse train having at least two or three pulses.

[0099] In some embodiments of the configurable fine tune Marx generator 400, the fine tune switches 410, 411, and 412 may be opened or closed by commands, or other types of control signals, from a controller. The switches 410, 411, and 412 may be fast acting and configured to withstand high voltages and high currents during pulse generation. By various combinations of opening and closing switches 410, 411 and 412, the voltage level on the fine tune out (+) terminal 493 may be, for example, 0, 50, 100, 150, 200, 250, 300 or 350 V. Closing switch 410 adds 50V to the voltage output of the fine tune Marx generator 400. Also closing switch 411 adds 100V to the output of the fine tune Marx generator 400, and closing switch 412 adds a further 200V to the output of the fine tune Marx generator 400. In some embodiments, a current limiting resistor 488 may be used for prevent over current when discharging into a low impedance load.

[00100] With continued reference to Fig. 4a showing an electrical circuit diagram of the fine-tune Marx generator 400 in which the generator 400 is configured, in this example, to be set to have an output voltage level of 0 volts which, in turn, may cause the overall voltage of the pulse generated by the pulse generator (including the fine tune and main Marx generator sections) to be 400-volts (e.g., using the main Marx generator unit of the pulse generator). In the configuration depicted in Fig. 4a, a high/low voltage selector switch 413 is closed, thus forming a path between the fine tune out (-) terminal 492 and the input 498 of the main Marx generator 470. In some embodiments, when all of the main Marx generator switches (only switches 414 and 415 of the main Marx generator are shown) are open, the pulse voltage that appears between the out (+) terminal 493 and the out (-) terminal 492 would be voltage on any of the capacitors of the main Marx generator, which is nominally 400V.

[00101] With reference to Fig. 4b, an electrical circuit diagram is shown of another embodiment of the fine-tune Marx generator 400 corresponding to another example switch configuration that causes the output of the generator 400 to be set to 50V (rather than to 0V as in the configuration of Fig. 4a). Setting the voltage output to 50V causes the generation of a 50V pulse according to some embodiments of the present disclosure. More specifically, the fine tune switch 410 may be closed while fine tune switches 411 and 412 are opened, causing a 50V output at the fine tune out (+) terminal 494. Because the high/low voltage selector switch 413 is open, the main Marx generator 470 is disconnected from the pulse path. As a result, voltage on fine tune out (+) terminal 494 appears on the out (+) terminal 493 after flowing through the bypass diode 468.

[00102] With reference to Fig. 4c, an electrical circuit diagram is shown of another embodiment of the fine-tune Marx generator 400 corresponding to another example switch configuration that causes the output of the generator 400 to be set to 50V to cause the generation of a 450V pulse according to some embodiments of the present disclosure. It is to be noted that in the example embodiments described in relation to Figs. 4a-d, the main Marx generator is configured to produce and to output a voltage level of 400V, which, depending on the configuration of the switch connecting the fine tune Marx generator to the main Marx generator, may be added to the voltage produced by the fine tune Marx generator 400. The main Marx generator may, however, be configured to produce various other voltage levels. Thus, in the example embodiment of Fig. 4c, and in contrast to the configuration depicted in Fig. 4b, the high/low voltage selector switch 413 is closed in Fig. 4c and, as consequently, the voltage on fine tune out (+) terminal 493 appears on the input of the main Marx generator 470 and is added to the 400V of the capacitors of the main Marx generator 470 (which includes the depicted capacitors 3 and 4).

[00103] Fig. 4d shows an electrical circuit diagram of an embodiment of the fine-tune Marx generator 400 corresponding to another example switch configuration, with the output of the generator 400 being set to 250V to cause the generation of a 650V pulse according to some embodiments of the present disclosure. To create a voltage of 250 V at the fine tune out (+) terminal 493, switches 410 and 412 are closed and switch 411 is opened. As a result, a voltage of: 1 *50 + 0* 100 + 1 *200 = 250V is generated. An arrow in Fig. 4d indicates the pulse current flow path created by the switches 410 and 412 being closed. In some embodiments, one or more forward or reversed biased diodes may be included in the pulse current flow path to provide for additional configurations. As described herein, each configuration involving the switches 410, 411 and 412 creates a different pulse current flow path and a different voltage at the fine tune out (+) terminal 493. As in Fig. 4c, the high/low voltage selector switch 413 is closed and, thus, voltage on fine tune out (+) terminal 493 is applied to the input of the main Marx generator 470 and is added to, for example, the 400V enabled by the capacitors of the main Marx generator 470.

[00104] Fig. 4e shows an electrical circuit diagram of an embodiment of the fine-tune Marx generator 400 during a fast discharge stage according to some embodiments of the present disclosure. A crowbar (or fast discharge) switch 444 may be closed for fast discharge of all the fine tune and main Marx capacitors. In such embodiments, the capacitors CO, CI and C2 of the fine tune Marx generator 400 are prevented from equalizing their voltage by the low voltage discharge diodes, which now closes the discharge paths. Fine tune blocking diodes prevent the voltage on capacitors CO, CI and C2 from appearing on the fine tune out (+) terminal. Note that due to the low voltage discharge diodes, the capacitor having the highest voltage among capacitors CO, CI and C2 may be the first to start discharging. Other capacitors join the discharging path as the LV discharge diode becomes forward biased and conducting. As shown in Fig. 4e, in some embodiments, the input line of the main Marx generator may be separated from the fine tune Marx out (-) terminal 492 by two back-to-back diodes, having their polarity such that the discharge path of the fine tune Marx generator 400 may be closed through the lower one. In some embodiments, the crowbar switch 444 may rapidly discharge the main Marx generator's 470 capacitors, with the discharge path passing through the top main Marx input/ fine tune Marx out (-) separation diode.

[00105] Fig. 5a shows an electrical circuit diagram of an embodiment of a configurable main Marx generator 500, where the output voltage is set to 400V according to some embodiments of the present disclosure. For purposes of describing the following embodiments illustrated in Figs. 5a-5g, a charging voltage of 400V is used. However, the charging voltage may be any desired voltage and is not limited to this example. The configurable main Marx generator 500 may be a modified implementation of Marx generator. In some embodiments of the present disclosure, the main Marx generator 500 may include one or more capacitors. The embodiments depicted in Figs. 5a-5g contain eight capacitors, numbered 503 through 510; however, the main Marx generator embodiments according to the present disclosure may contain any number of capacitors of any variety of given capacitances to achieve the desired objectives.

[00106] In some embodiments, all of the capacitors 503-510 of the generator 500 may be charged in parallel to 400V using charging line 521 and charging line 522 through of a chain of charging resistors 533 and a chain of charging resistors 534. As described herein, in some implementations, the charging resistors may be replaced with switches (e.g., transistors) and diodes to enable the charging time to be reduced, and to enable the charging process to be more energy efficient (because less energy will be dissipated due to the lower resistance of the diodes and/or transistors). For example, and with reference to Fig. 5i, an electrical circuit diagram of an example embodiment of a configurable main Marx generator 500 is shown. In the example depicted in Fig. 5i, the charging resistors 533 and 534 shown, for example, in Fig. 5a, are replaced with switches 535 (which may be implemented using transistors controllable by, for example, a controller such as the controller 110) and diodes 536. These switches and/or diodes are electrically coupled to at least some of the capacitors 503-510 of the main Marx generator 500, and enable a faster charging operation of the at least some of the capacitors as a result of their lower resistance (e.g., when these components are active). Thus, in some embodiments, the Marx generator (which may include a configurable fine tune section and a configurable main section) may be configured for fast charging of at least some of the plurality of capacitors using one or more of a switch (e.g., a transistor) and a diode to implement charging resistance electrically coupled to the at least some of the plurality of capacitors. Although Fig. 5i shows the implementation of charging resistance using switches and diodes in relation to a main Marx generator, a similar implementation of charging resistance using switches and/or diodes can also be done for fine tune Marx generators, such as the fine tune Marx generator 400 depicted in Figs. 4a-e.

[00107] In some embodiments, the capacitors 503-510 may be grouped in pairs, such as for example the pairs 503/504, 505/506, 507/508 and 509/510. In some such paired configurations, the paired capacitors may be connected in parallel via pair blocking diodes dl l/d21, dl2/d22, dl3/d23, dl4/d24, d31/d41, d32/d42, d33/d43 and d34/d44. Some paired capacitor embodiments may be connected in series with gap switches 514, 516, 518 and 520, as shown in Figs. 5a-5g.

[00108] The four capacitor pairs, namely 503/504, 505/506, 507/508 and 509/510, shown in Figs. 5a-5g may be connected in parallel to the main Marx input line 550 and the out (+) line 560 via HV group blocking diodes D01, D02, D03, D04, Dl l, D12, D13 and D14. The number of group blocking diodes and pair blocking diode arrangements may vary according to the voltage used and the selection of diodes and the maximum voltage they can withstand. In some embodiments, capacitor pairs adjacent to one another, for example 503/504 and 505/506, may be connected in series by closing gap switches 515, 517 and 519.

[00109] According to some embodiments, the gap switches 514-520 may be controlled by a controller (such as the controller 110 of Figs, la and lb) configured to connect the capacitors 503-510 in various ways/arrangements to achieve a desired voltage output of the main Marx generator 500. For example, connecting two or more of the capacitors 503-510 in series causes voltages to be added. However, connecting two or more of the capacitors 503-510 in parallel causes capacitances to be added and the charge available for the pulse increases. The gap switches 514-520 may be any suitable type of electrical switch (e.g., IXGR32N170AH1 solid state HV switches, other insulated gate bipolar transistor-based switches, other transistor-based switches, electromechanical switches, etc.) and, in some embodiments, may be fast-acting and configured to withstand high voltages and/or high currents during pulse generation operations. In some embodiments, the group blocking diodes (D01, D02, D03, D04, Dl l, D12, D13 and D14) and/or pair blocking diodes dl l/d21, dl2/d22, dl3/d23, dl4/d24, d31/d41, d32/d42, d33/d43 and d34/d44 may be forward biased so as to act as (nearly) shorts and/or reversed biased so as to act as a substantially open circuit. Embodiments of the main Marx generator 500 may also include current limiting resistors 555 to limit the pulse current so as to avoid over current in the event of low impedance load.

[00110] As shown in Fig. 5a, when a switch 513 is closed, the voltage between out (-) line 540 and the out (+) line 560 may be the sum of the voltage of the main Marx generator 500 plus the voltage of the configurable fine tune Marx generator (not shown in Fig. 5a). This summed voltage will appear at the input of the main, polarity and discharge switches section (not shown). As also depicted in Fig. 5a, the gap switches 514-520 may be open and all capacitors 503-510 may thus, in that situation, be connected in parallel and be collectively connected in series to the fine tune Marx generator, resulting in an output voltage equal to the "fine tune" voltage, plus the voltage from the main Marx generator 500. In this configuration, the main Marx generator 500 may act as a gang (bank) of capacitors, all connected in parallel. The pulse current flow path is depicted by arrows positioned along the various charging, input and output lines in Fig. 5a. In some embodiments, such as that shown in Fig. 5a, all the capacitors 503-510 of the main Marx generator 500 participate in the pulse generation. Accordingly, the total equivalent capacitance of the main Marx is 8*C, where C is the capacitance of a single capacitor.

[00111] Fig. 5b shows an electrical circuit diagram of an embodiment of another configuration of the main Marx generator 500, in which output voltage of the generator 500 is set to 800V according to some embodiments of the present disclosure. By closing switch 514, capacitors 503 and 504 are connected in series and yield a voltage of 800V between the main Marx input line 550 and the out (+) line 560. This voltage may cause reverse biasing of the group blocking diodes pairs D02/D12, D03/D13 and D04/D14, such that only the first group of capacitors 503/504 are along the pulse current flow path. Moreover, in some embodiments, the pair blocking diodes dl l and d41 may be reversed biased so as to leave capacitors 503 and 504 connected in series such that the pulse current flow path passes through pair blocking diode d31, through the capacitor 503, across the gap switch 514, through the capacitor 504, through pair blocking diode d21 and the group blocking diode Dl 1, as shown by the arrows in Fig. 5b.

[00112] In turn, the total charge available to the pulse is a charge of two capacitors, while the equivalent capacitance is C/2 (in circumstances where the capacitors have substantially equal capacitance). The capacitors not on the marked pulse path, namely the capacitors 505- 510, do not participate in the pulse discharge due to the reversed biased diodes that act as open circuits. Thus, capacitors 505-510 stay fully or nearly fully charged and may be discharged immediately or later in a following pulse in a pulse train. Thus, in such implementations, after one pulse is delivered, the pulse generator may be reconfigured (e.g., by reconfiguring the open/close states of the switches) to enable the next pulse in the train (having determined attributes such as starting and end voltage levels, duration, etc.) to be delivered. The reconfiguration of the pulse generator (the generator 500 and/or the generator 400) may be performed by control signals generated by the controller. Accordingly, in some embodiments, where a pulse train is to be delivered to the load, with each of the pulses in the train associated with a corresponding set of attributes, the pulse generator may be operable/adapted to be reconfigured after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated. The pulses generated can thus be generated by reconfiguring the electrical pathways, and without recharging the capacitors, until the last pulse in the train has been delivered. In some embodiments, some recharging functionality of the capacitors during delivery of a pulse train may be allowed and implemented.

[00113] In some implementations, and as further discussed below, as soon as the voltage on C3 and C4 drops to 200V each, the pair and group blocking diodes of the other capacitor pairs become conductive and capacitors 505-510 join the pulse current flow path in parallel.

[00114] In some embodiments, a pulse may be terminated before the capacitors are completely discharged. This may be done by limiting the pulse duration or by opening the polarity switches shown in Figs, la, lb and 7 (as described in the accompanying descriptions). Pulse termination may be timed or determined using pulse feedback (as more fully detailed in Figs, la-b, 8, 9 and 14a-d, and in the descriptions accompanying these figures). Higher capacitance may be introduced to the pulse current flow path by, for example, also closing any of switches 516, 518 or 520, or any combination of switches 514, 516, 518 or 520. In some embodiments, it may be advantageous to use all the capacitors pairs (where each pair may be connected in series), to thus obtain an equivalent capacitance of 4*C (less tilt), with the charge distributed evenly, in some embodiments, between all the capacitors so as to enable such a configuration to be in a better position to generate the next pulse.

[00115] Fig. 5c shows an electrical circuit diagram of an embodiment of the main Marx generator 500, in which the voltage output of the generator 500 is set to 1,200V according to some embodiments of the present disclosure. In the example embodiment illustrated in Fig. 5 c, gap switches 514 and 515 are closed such that capacitors 503 and 504 are connected in series with each other and with capacitors 505 and 506 (the capacitors 505 and 506 are connected in parallel to each other). In some embodiments, twice the capacitance may be introduced to the pulse current flow path by also closing gap switches 518 and 519. It is to be noted that this configuration provides an equivalent circuit of 3 different capacitors (C, C, 2*C) connected in series, or of two capacitors C/2 and C, where the first one is charged to 2V and the second one to V.

[00116] It is to be noted that the configurations of Figs. 5b and 5c are low capacitance configurations. By properly controlling the switch configurations, the capacitance of the pulse generator can be increased, e.g., by engaging the capacitors on the right side of the main Marx generator. [00117] Figs. 5d-f demonstrate the flexibility of embodiments of the main Marx generator 500 according to the present disclosure by depicting various ways to generate the same output voltage of 1,600V. First, Fig. 5d shows an electrical circuit diagram of an embodiment of the main Marx generator 500, in which the voltage output of the generator 500 is set to 1,600V according to some embodiments of the present disclosure. In this example embodiment, the gap switches 514, 515, and 516 are closed such that only capacitors 503, 504, 505 and 506 are part of the pulse current flow path while connected in series. The capacitors 507, 508, 509 and 510 are blocked by the group blocking diodes D02, D03, D04, D13 and D14 and/or pair blocking diodes d42, d33, d43, d34, d44, dl3, d23, dl4 and d24 from the pulse path. The equivalent capacitance is one quarter of the individual capacitance; however, capacitors 507, 508, 509 and 510 retain full charge as long as the pulse terminates before its voltage drops to 400V. Thus, a second pulse with starting voltage of 1,600V may be generated by closing the gap switches 518, 519 and 520.

[00118] Fig. 5e shows an electrical circuit diagram of an embodiment of the main Marx generator 500, in which the voltage output of the generator 500 is again set to 1,600V. In this example embodiment, the gap switches 514, 515 and 516 are closed, along with the gap switches 518, 519, and 520 such that all the capacitors 503-510 are on the pulse current flow path forming two capacitor chains, namely, 503-506 and 507-510 connected in parallel. The equivalent capacitance is one half of the individual capacitance; however, all the capacitors 503-510 are partially discharged during the pulse. Thus, a second pulse with starting voltage of 1,600V may be generated, for example, by compensating for the drop of voltage in the main Marx generator (500) by adding voltage by the fine tune Marx generator (not shown). The six gap switches 514-516 and 518-520 that are in operation in this configuration, are arranged in two chains of three switches connected in series. If each switch has impedance of R, the contribution of the switches to the path total impedance is 1.5*R.

[00119] Fig. 5f shows an electrical circuit diagram of an embodiment of the main Marx generator 500, in which the voltage output of the generator 500 is again set to 1,600V according to some embodiment of the present disclosure. In this embodiment, the gap switches 515, 517 and 519 are closed such that all the capacitors 503-510 are on the pulse current flow path forming four parallel-connected capacitor pairs, namely, 503-504, 505- 506, 507-508 and 509-510, with those four pairs being connected in series. The equivalent capacitance is one half of the individual capacitance. As in the example embodiment of Fig. 5e, all the capacitors 503-510 are partially discharged during the pulse. Thus, a second pulse with a starting voltage of 1,600V may be generated by, for example, compensating for the drop of voltage in the main Marx generator 500 by adding voltage by the fine tune Marx generator (not shown). Thus, in this configuration, three switches arranged in a single chain are in operation. If each switch has impedance of R, the contribution of the switches to the path total impedance is 3*R.

[00120] Fig. 5g shows an electrical circuit diagram of an embodiment of the main Marx generator 500, in which the voltage output of the generator 500 is set to a maximal voltage of 3,200V. In this embodiment, all of the gap switches 514-510 are closed, such that all of the capacitors 503-510 are part of the pulse current flow path forming a chain connected in series to yield a maximum main Marx generator voltage of 3,200V. Thus, the maximum pulse voltage attainable is the sum of the 350V voltage produced by the example fine tune Marx generator described herein (not shown in this figure), and the 3,200V voltage produced by the example main Marx generator 500, for a total voltage of 3,550V.

[00121] In some embodiments, when capacitance is larger for the capacitors in the fine tune Marx generator, the voltage drop during a pulse is small in those capacitors. Thus, repeated pulses may be fine tuned by the fine tune Marx generator. Moreover, by knowing or measuring the amount of discharge in each pulse, it is generally possible to configure the entire generator to produce a desirable voltage within the limit availability of charge in the capacitors and available switches.

[00122] As there may be several switches configurations yielding the same initial voltage of a pulse, there are several considerations for selecting a desired configuration. First, to reduce pulse tilt, it may be better to have capacitors connected in parallel to increase the available charge. Second, it may be better to use fewer switches in series on the pulse current flow path because the switches may present parasitic resistance. Other consideration may also be taken into account when determining (e.g., by a controller, such as the controller 110 of Fig. la) a configuration of the pulse generator.

[00123] The pulse generator according to the embodiments of the present disclosure may be reconfigured in many various ways to generate a plurality of different pulses and pulse trains. In some embodiments, some configurations may cause over voltage on one or some of the switches and/or diodes. Generally, it may be desirable to avoid such configurations. Optional appropriate protection circuitry may limit the voltage on the switches and the connection of several diodes in series prevent their over voltage condition. Additionally, preferred switch configurations may be stored in and selected by a controller. Additionally, some configurations may be marked as unsafe or illegal and may thus be avoided by the controller.

[00124] Fig. 5h shows an electrical circuit diagram of an embodiment of the main Marx generator 500 during a fast discharge stage according to some embodiments of the present disclosure. In such embodiments, a fast discharge switch 595, or crowbar, may be closed for fast discharge of all the fine tune and main Marx capacitors. The discharge path for the capacitor 510 is depicted in Fig. 5h with arrows. Similar discharge paths for the capacitors in the fine tune generator (not shown) and the capacitors 503-506 and 509 of the main Marx generator 500 may be similar and not marked. The discharge path for the serially connected capacitors 507 and 508 is also depicted by arrows in Fig. 5h. In this embodiment, in which only the gap switch 518 is closed, the capacitors 507 and 508 will start to discharge first, keeping any and all blocking diodes leading to other capacitors in a reversed biased state. However, whatever combination of switches is selected, all the capacitors 504-510 will be eventually discharged. As also shown in Fig. 5h, the main Marx input line is separated from the out (-) line 540 by two back-to-back separation diodes 585, where the polarity of the diodes 585 is such that the discharge path of the main Marx generator 500 may be closed through the top one. In some embodiments of Fig. 5h, discharge current may also be limited by a fast discharge current limiting resistor 556 as well as current limiting resistors 555 within the pulse current flow path.

[00125] In some implementations, the load may be disconnected while the fast discharge takes place. This may be done, for example, by opening the main output switch, and then closing the fast discharge switch 595. Any manipulation of switches during the discharge should be avoided, since it might result in large voltage transients which might damage the switches.

[00126] Fig. 6 shows an electrical circuit diagram of an embodiment of an optically-driven switch 600 configured for use in a pulse generator according to some embodiments of the present disclosure. Various switches in the circuit may differ depending on the voltage they need to withstand during hold-off "open stage," the current they need to conduct during conduction "closed stage," and the speed in which they need to switch between closed to open stages. In some embodiments, the switch 600 may be floating and powered during its operation by an energy storage capacitor 610, charged by a 20V power supply. To activate the switch 600, a TTL drive pulse 620 may be delivered to an optical coupler 630 (e.g., Optek OPIl lOC), which becomes conductive and delivers, for example, the 20V charge on the capacitor to a gate driver 640 (e.g., the IXDD509), which boosts the output of the optical coupler 630 before it is delivered to the gate of the transistor 645, thus closing the switch 600. A chain of Zener diodes 650 (e.g., BZG03C270) may be used across the switch terminals for over voltage protection. In some embodiments, the circuit in Fig. 6 is for a 4kV IGBT, which can be readily seen by the values and number of the Zener diodes 650. The same or similar circuitry is used for the 1.7kV switches, but with the appropriate types and/or number of Zener diodes. In some embodiments, a Zener diode may be used at the transistor gate. In some embodiments, an LED indicator may be connected to the driver output to indicate closing of a switch 600. Some of the switches may be slowed down by adding a capacitor 660 and resistor 670 to the transistor gate connection. These elements may have different values depending on the desired rise/fall time of the switch. It is to be noted that a reason to slow down the operation of the switch is to prevent large transients due to the large d//dt (current time derivative) values and the parasitic inductance of the circuit (mainly due to the patient leads).

[00127] Fig. 7 shows an electrical circuit diagram of an embodiment of a discharge, main and polarity reversing switches section 700 of a pulse generator according to some embodiments of the present disclosure. A main pulse relay or switch 710 may be used for disconnecting the pulse generated by the Marx generators from the shock leads (not shown). The main pulse switch 710 is depicted in Fig. 7 along the out (+) line 720; however, it may be situated on the out (-) line 730 as well. In some embodiments, two main pulse switches may be used, one on the out (-) line 730 and the other on the out (+) line 720. In some embodiments, opening the main pulse switch 710 may be used for terminating a pulse. In these embodiments, transients caused by inductance in the pulse path (which includes also the shock leads and load) may cause over voltage. Slowing down of the main pulse switch 710, as well as Zener diodes protection may be used in this switch. In some embodiments, the main pulse switch 710 may be controlled by a controller (such as the controller 110 of Fig. la).

[00128] Fig. 7 also shows that polarity switches 750 and 760 may be used for reversing the polarity of a generated pulse. The polarity switches 750 and 760 may also be controlled by a controller (such as the controller 110, or by a different controller). Moreover, when all of the polarity switches are open, no HV voltage will appear between a first shock line 770 and a second shock line 780. When the two direct polarity switches 750 are closed, the out (+) line 720 is connected to the first shock line 770 and the out (-) line 730 is connected to the second shock line 780. When the two reversed polarity switches 760 are closed, the out (-) line 730 is connected to the first shock line 770 and the out (+) line 720 is connected to the second shock line 780. Thus, the polarity switches 750 and 760 can start, reverse and/or terminate the generated pulse and/or any one or several pulses in a pulse train. In some embodiments, polarity reversing switches change states before a pulse or between pulses.

[00129] Fig. 8 shows an electrical circuit diagram of an embodiment of a load impedance measuring, pulse sensing and lead connectors section 800 of a pulse generator according to some embodiments of the present disclosure. Embodiments of the section 800 may include a voltage sensor 802, a current sensor 804 and an over current sensor 806, as well as first and second shock lines 812 and 814 and a chain of one or more resistors 816 therebetween. The voltage sensor 802 and/or current sensor 804 may be used to monitor the voltage and current delivered to the load 880, respectively. These sensors may include isolated pickup coils so that their output is isolated from the high voltage pulse (e.g., Rogowski coils). In some embodiments, readings of the sensors may be amplified or otherwise conditioned before being digitized by an ADC. Some embodiments of section 800 may include the ADC to digitize the signals indicative of current, voltage and/or power, which may then be used by a controller (such as the controller 110 of Fig. la) to dynamically determine pulse parameters or pulse train parameters, including without limitation, pulse duration or accumulated charge and/or energy, and configure the pulse generators (e.g., through control signals corresponding to the determined parameters) for the determined parameters/attributes. In some embodiments, the controller may determine control signals directly based on the measurements without determining (as an intermediate operation) pulse attributes. In some embodiments, signal threshold determination, signal integration and scaling may be performed by software in a controller. Thus, in some implementations, a device or a system (which may include, or may itself be, the pulse generator) may include at least one sensor to measure at least one characteristic associated with the target load (e.g., the cardiac tissue of the patient). In such implementations, the pulse generator may be adapted to generate the one or more electrical pulses with one or more attributes/parameters that are determined based, at least in part, on the measured at least one characteristic associated with the target load. The section 800 may further include a real-time analog multiplier 830. In some embodiments, voltage signals may be multiplied by the current signal using the real-time analog multiplier 830 to generate a signal indicative of the power delivered to the leads. In some embodiments, one or more analog accumulators (not shown) may be used to generate signals indicative of accumulated delivered charge and energy by integrating the signal of the current and power, respectively. In some embodiments, threshold devices (not shown) may create trigger signals when current, charge, voltage, power and/or energy surpasses a predetermine value. These accumulated signals or triggers may be used for monitoring the pulse and/or load behavior or as indications that a pulse may need to be terminated. In some embodiments, real-time impedance is calculated by real-time division of the voltage signal by the current signal. The real-time calculated impedance may be used to dynamically control the pulse parameters by reconfiguring the switches in the fine tune and/or main Marx generators of the present disclosure. The latter may be done either for the present pulse that it to be delivered to the load, or for consecutive subsequent pulse(s) in the pulse train. In some embodiments, the controller may monitor pulse voltage and current and may act to terminate a pulse should the pulse exceed a desired or safe operation parameters. In some embodiments, a fast analog threshold unit connected to the pulse voltage sensor acts to terminate the pulse on detecting over voltage.

[00130] In some embodiments, an extra current transformer 840 may be provided to allow a faster shutdown in the case of a short or a spark breakdown between electrodes 884 (e.g., caused by them being too close). The transformer 840 may be configured to enable an isolated measurement of the impedance. The load impedance is reflected to its primary winding, and thus, a voltage divider is provided between the reflected load impedance and the 50 Ohm resistor 842 shown in Fig. 8. The voltage on the resistor 842 can then be measured to determine from that measurement the load impedance. The over current sensor 806 may be used to stop very high current building up before the precision programmable current trip has time to respond. In some embodiments, the over current sensor 806 may have a fixed current threshold set to trip at about, e.g., 70 amps.

[00131] In some embodiments, the unit/section 800 may also include one or more lead connectors 882 connected to corresponding leads 886 having two or more electrodes 884 in contact with a load 880 (e.g., heart of a patient). As will be discussed in greater detail below, in some implementations, 3, 4, or more electrodes may be used. Devices/systems that include more than 2 electrodes may be implemented, for example, using a single pulse generator device that includes extra relays and switches to enable delivery of pulses via different arrangements of the electrodes, and/or may include multiple devices/systems (such as the device/system depicted in Fig. la) that each has two or more electrodes through which pulses may be delivered to different locations of the load. When using implementations that include two or more devices, the two or more devices may be configured and synchronized to operate in concert. For example, the various multiple devices used may be coupled to each other in a master/slave configuration. Use of one implementation or another (e.g., using a single pulse generator device with multiple electrodes as opposed to using multiple pulse generators) may depend, for example, on whether a simultaneous delivery of pulses is required for different pairs of electrodes.

[00132] The leads 886 may be connected either to the pulse generating circuit or to a low voltage load impedance sensing circuit via a HV impedance sense/shock relay 890. The load impedance sensing circuit may be used for determining the load AC impedance, for example, at frequencies similar to the frequencies present in the pulse, but at low voltage. An AC signal generator 844, for example at 100 kHz, may send a low voltage signal through the leads 886 and to the load 880. The resulting current may be used for calculating the impedance. In some embodiments, both current and phase relative to excitation voltage may be measured so that complex impedance may be measured. In some embodiments, several frequencies may be monitored. Knowing the impedance before generating and/or delivering a pulse allows, for example, the determination of proper electrode placement and computing the voltage needed for delivering a desired energy within a desired pulse duration, or, for example, whether the desired pulse parameters would exceed the energy or current limits. Measuring the impedance following the pulse may indicate load or load-electrode contact change due to the pulse. The leads 886 may be connected to the pulse generator via the connectors 882 such that the leads 886 may be replaced, for example, before they are used for defibrillating a different patient. Thus, in some embodiments, the at least one sensor to measure the at least one characteristic associated with target cardiac tissue of the patient may be configured to measure electrical impedance of the load (e.g., the target cardiac tissue). In such embodiments, a controller may be adapted to dynamically configure the pulse generator to generate the one or more pulses with the one or more attributes determined based, at least in part, on the measured electrical impedance of the load.

[00133] Fig. 9 shows an electrical circuit diagram of an embodiment of a controller unit/section 900 of a pulse generator according to some embodiments of the present disclosure. The controller section 900 may include a controller 910 (which may be similar to the controller 110 of Fig. la) for controlling the operations and functionality of an associated pulse generator within which the controller section 900 may be contained. In some embodiments, the controller section 900 may be external to an associated pulse generator. As noted herein, the controller 910 may be a processor-based device including, for example, a CPU, a complex programmable logic device (CPLD) or any other appropriate computing device or mechanism. To facilitate operation of the controller section 900, the controller 910 itself may be connected to one or more subsystems, including without limitation, a memory, a clock, one or more input devices (e.g., a keyboard, mouse and/or keypad) and one or more output devices (e.g., a display and/or indicators, such as LEDs). The controller 910 may be connected to one or more control lines for controlling the operation of the pulse generation circuitry. The controller 910 is configured to receive, in some implementation, digital data from sensors sensing parameters, such as load impedance and HV charge voltage and pulse behavior data (e.g., pulse voltage, pulse current and/or discharge energy), and based on the received data to compute adjustable attribute values for pulses that are to be applied to the load and/or to generate the control signals to reconfigure the pulse generator.

[00134] In some embodiments, the controller 910 may control the power supply (see, for example, Fig. 2), the gap switches (shown, for example, in Figs. 4a-4e, and 5a-5h), and/or the HV relays. The controller 910 may also receive digital information from one or more ADC components and use at least some of this data for real-time control of a pulse or a pulse train. Some embodiments of the present disclosure may involve the controller 910 functioning as a real-time, high-speed controller, such as a CPLD, that controls the gap switches of the fine tune Marx generator and/or the main Marx generator during pulse creation. Such a real time, high speed controller may monitor the ADC and other inputs, such as external triggers and clock inputs, to dynamically control the pulse. A non-real-time processor may be used to program and prepare the parameters for the real-time controller. The non-real-time processor may be used, for example, for interfacing with a user (e.g., via a keyboard, a mouse, and/or some other input device) and/or with an external or a remote server via a communication module.

[00135] Embodiment of the controller section 900 may employ one processor to perform all necessary operative tasks and functions or, alternatively, the controller section 900 may divide operatives tasks and function among a plurality hardware and software modules. The section 900 may also have an abort button 924 to disable any pulse generation and/or the power supply and discharge all the capacitors. The abort button 924 may act directly on switches and relays and/or through the controller 910. The controller 910 memory may include a plurality of pulse and pulse train pre-programmed parameters. In some embodiments, the generation of a pulse or pulse train is activated by an input device. In some embodiments, the generation of a pulse or pulse train may be activated by receiving a trigger command. The controller 910 programming may include a rule or set of rules that determines the switch configuration for generation of a desired pulse voltage or a specific pulse train. In some embodiments, the controller 910 programming may be configured to prevent impermissible/invalid switch configurations, such as shorting the out (+) line and the out( -) line by, for example, closing both direct and reverse switches at once.

[00136] Fig. 10a shows an equivalent electrical circuit diagram of Marx generator capacitors Ci and C₂ during pulse discharge of a pulse generator according to some embodiments of the present disclosure. In some switch configurations, not all capacitors connected in series in the pulse path may be of the same capacitance. The smaller capacitor Ci may be fully discharged before the large capacitor C₂ is discharged. Continuing the pulse current after this point may cause reverse charging of the smaller capacitor Ci by current from the larger capacitor C₂ (or an equivalent capacitor if a few are connected). Additionally, in pulses other than the first pulse in a pulse train, some capacitors may not be fully charged as they were at least partially discharged in a previous pulse or pulses. In some embodiments, a capacitor along the pulse path, which is fully discharged during a pulse, may start to be negatively charged by the pulse current itself. This causes a rapid decrease in pulse voltage and drains energy which could have been used for pulse generation or for capacitor charging.

[00137] To prevent such reverse charging, a bypass diode 1040 may be placed in the circuit, as seen in Fig. 10a. In Fig. 10a, capacitors Ci and C₂ may be charged to voltages Vi and V₂, respectively. One bypass diode 1040 is positioned across the smaller capacitor Ci in Fig. 10a; however, bypass diodes 1040 may be placed across both capacitors Ci and C₂. When capacitor C_ls having the smaller charge, is completely discharged, the reversed biased bypass diode 1040 becomes forward biased and acts as a short across capacitor Ci. The role of a bypass diode is taken by various blocking diodes in the fine tune Marx generator and blocking diodes d and blocking diode chains D in main Marx generator embodiments. It is to be noted that the blocking diodes prevent the lower capacitance from being reversely charged.

[00138] Fig. 10b shows a pulse waveform generated by the electrical circuit depicted in Fig. 10a according to some embodiments of the present disclosure, showing schematically the waveform with and without the bypass diode. The equivalent capacitance of the serially- connected capacitors Ci and C₂ is smaller than the capacitance of capacitor C₂ alone. This causes a relatively fast decay of pulse voltage. When capacitor Ci is fully discharged, the pulse current bypasses capacitor Ci. In the bypass diode configuration, the pulse decay continues at a slower rate, as depicted by the heavy-lined graph, instead of continuing to decay rapidly, as seen in the dashed graph.

[00139] Figs. 11a and l ib show an embodiment of an implementation of Figs. 10a and 10b in a main Marx generator 1100 according to some embodiments of the present disclosure. In Figs. 11a and l ib, a gap switch was replaced with dual switches si and s2 serially connected and Zener diodes 1117 connected across the dual switches si and s2 according to an embodiment of the present disclosure. During pulse generation, the voltage across the dual switches si and s2 may be as high as 1600V (or higher). In some embodiments, the Zener diodes 1117 may ensure that the voltage across a single switch does not exceed its hold-off limit. As also shown in Figs. 11a and l ib, capacitors 1103 and 1104 may be connected in parallel and exhibit an equivalent capacitor of C₂ = 2*C, where C is the capacitance of any of the individual capacitors. The voltage across capacitors 1103 and 1104 may thus be V₂ = 400V. In some embodiments, capacitors 1105 and 1106 may be connected in series by closure of gap switch 1115, exhibiting an equivalent capacitor of Ci = C/2, where C is the capacitance of all the individual capacitors. The voltage across the equivalent capacitor Ci may thus be Vi = 800V. Capacitor groups Ci and C₂ may be connected in series by closure of gap switch 1115, resulting in 400V + 800V = 1,200V total voltage. The equivalent circuit is then the one showed in Fig. 10a. An identical configuration may be replicated with respect to capacitors 1107-1110 and gap switches 1119 and 1120; while open dual switches si and s2 keep the left and right hand sides of the main Marx generator 1100 independent of each other and thus connected in parallel to each other. During pulse discharge, the behaviors of the right and left hand sides may be similar and thus will not be repeated.

[00140] Fig. 1 lb shows the discharge current path during the later part of the pulse. When the capacitor chain is discharged, voltage across each of the capacitors 1105 and 1106 may decrease at a rate twice the decrease in voltage on capacitors 1103 and 1104. If the pulse duration is long enough, capacitors 1105 and 1106 may become fully discharged to zero voltage. The role of bypass diodes across equivalent capacitor Ci (e.g., the capacitors 1105 and 1106) may be played by the blocking (bypass) diodes Dl 1 marked, as shown in Fig. 1 lb, which shorts circuit the equivalent capacitor C₂ to the out (+) line 1140. In some embodiments, actual bypass diodes may be placed across some or all capacitors in the main Marx generator and/or the fine tune Marx generator. The circuit may be analyzed to predict pulse evolution/development for a plurality of initial charges, capacitor values and switch configurations (e.g., static or changing). For example, an LV bypass diode may be used to bypass the entire main Marx generator if the fine tune Marx generator retains some charge while the main Marx generator is sufficiently discharged, even if a switch is closed. Diodes in the fine tune Marx generator may be used for bypassing capacitors within the fine tune Marx generator.

[00141] Fig. 12a shows an equivalent electrical circuit diagram of a configurable main Marx generator's capacitors Ci and C₂ during pulse discharge of a pulse generator according to some embodiments of the present disclosure. In some embodiments, the capacitors Ci and C₂ may be connected in parallel, where capacitor C₂ is charged to a voltage V₂ that is greater than a voltage Vi to which capacitor Ci is charged. A blocking diode 1240 may be connected in series to capacitor Ci. In some embodiments, blocking diodes may be placed in series with both capacitors Ci and C₂. When a capacitor is connected in parallel to another capacitor, current from the capacitor having higher voltage flows into and charges the capacitor with the lower voltage. In some embodiments, it may be advantageous to prevent charging a capacitor using the charge of another capacitor with higher voltage during the pulse. This may lead to a waste of charge and energy and decrease the voltage that can be delivered to a load. To prevent such undesired charging, blocking diodes may be placed in the circuit.

[00142] Fig. 12b shows a pulse waveform generated by the electrical circuit depicted in Fig. 12a according to some embodiments of the present disclosure and, more specifically, shows the pulse waveform with and without the blocking diode. At the beginning of the pulse, capacitor C₂ alone contributes to the pulse. This causes a relatively fast decay of pulse voltage. When capacitor C₂ is discharged to the voltage V_{l s} the blocking diode 1240 may become conductive and capacitor Ci becomes connected in parallel to capacitor C₂. Thus, the equivalent capacitance becomes Ci+C₂, and pulse decay continues at slower rate as depicted by the heavy line in Fig. 12b, instead of continuing to decay rapidly along the dashed line shown in Fig. 12b.

[00143] Figs. 13a and 13b show an embodiment of an implementation of Figs. 12a and 12b in a main Marx generator 1300 according to some embodiments of the present disclosure. More specifically, Figs. 13a and 13b show first and second stages, respectively, of the pulse path of a pulse during the pulse discharge of the equivalent electrical circuit of Figs. 12a and 12b. Fig. 13a shows an embodiment of implementation of Figs. 12a and 12b in a pulse generator in a first stage of discharge. As shown in Fig. 13a, a first group of capacitors 1303 and 1304 may be connected in parallel, as well as a second group of capacitors 1305 and 1306. The first and second groups of capacitors, in some embodiments, may be connected in series by the closure of a gap switch 1315. As a result, the output voltage of the first and second groups together may be 800V, when the voltage feeding/powering the main Marx generator 1300 is, for example, 400V. The first and second capacitor groups may be viewed as one equivalent capacitor C₂, as denoted in Fig. 13a, that is charged to V₂ = 800V. The remaining capacitors 1307-1310 in the main Marx generator 1300 may be connected in parallel and viewed as a third capacitor group that acts as an equivalent capacitor Ci, also denoted in Fig. 13a, that is charged to Vi = 400V.

[00144] While, for the sake of clarity in the figures, only a few blocking diodes have been depicted, any number of blocking diodes may be implemented. In some embodiments, a single blocking diode may be used within any of the first, second and/or third capacitor groups. Moreover, a chain of three diodes may be used between the groups and/or the out (-) line 1370 and fine tune out (+) line due to the higher blocking voltage needed.

[00145] Fig. 13b shows an embodiment of an implementation of Figs. 12a and 12b in a pulse generator in the second stage of discharge, namely at and after the time when equivalent capacitor C₂ has discharged to the voltage of equivalent capacitor Ci (i.e., to 400V). At this point, blocking diodes become bypass diodes and equivalent capacitor C₂ becomes connected in parallel with equivalent capacitor Ci. From this point on, the two equivalent capacitors Ci and C₂ discharge together to the load as depicted by the solid and dashed arrows of Fig. 12b.

[00146] Figs. 14a-14d show pulse train waveforms generated by a pulse generator according to some embodiments of the present disclosure. In Fig. 14a, a dual pulse train of two pulses having the same polarity is displayed. Parameters of the pulses, including, without limitations, initial pulse voltage, end of pulse voltage, voltage drop (also termed "tilt," which refers to the difference between initial and final pulse voltage as a percentage of the initial pulse voltage), pulse duration and interval between pulses are marked in Fig. 14a. In some embodiments, tilt may be determined by the impedance and equivalent capacitance (e.g., selected during manufacturing by using specific capacitor values and/or by selecting switch configurations). Pulse rise-time and fall-time may be determined by the switches and impedance of the pulse path. [00147] Before a pulse is initiated, a power supply of the pulse generator may be turned on. In some embodiment, a desired HV voltage to be delivered by the power supply may be selected. As a result of turning on the power supply, one or more capacitors in the pulse generator may be charged. Charging of the capacitors may be verified by a monitoring system. Before initiating the delivery of a generated pulse, the power supply may be disconnected by opening charging relays or switches as a safety measure. In some embodiments, impedance sense/shock relays may be switched to connect shock lines to shock leads, disconnecting and protecting the impedance sensing section from the pulse.

[00148] To initiate pulse generation, the configuration of switches may be set by a controller (e.g., such as the controller 110 of Fig. la) and the pulse may be initiated by closing the main switch. In some embodiments, one or more polarity switches may be opened. The pulse may be terminated by opening the main switch. Abrupt termination of a pulse may be initiated, for example, in response to a fast current sensor sensing over current, a current sensor sensing current that is too high or too low, a voltage sensor sensing over voltage, voltage that is too low or voltage that decays too fast or too slow, an unusual reading by an energy sensor and/or any other anomalous sensor data reading.

[00149] In some embodiments, pre-programmed termination of a pulse may be initiated, for example, based on (i) time, where a controller monitors the elapsed time since initiation of the pulse, (ii) an accumulated charge reaching a preset value (e.g., an accumulated charge in a pulse may be determined by analog or digital integration of the current sensor reading or by monitoring the voltage drop sensed by the voltage sensor and knowing the effective capacitance), (iii) cumulated delivered energy reaching a preset value (e.g., the accumulated energy delivered in a pulse may be determined by analog or digital integration of the power, as sensed by an analog multiplier of the current and voltage signals), (iv) voltage dropping to a preset value and/or (v) current dropping to a preset value.

[00150] Some embodiments of the present disclosure may involve an optional second pulse and a re-configuration of the switches adapted to facilitate the second pulse parameters, where the desired polarity switches are closed and opened. In some embodiments, a controller may process/analyze sensors' readings from a pulse to determine the switch configuration or other parameters of the next pulse. For example, current or voltage readings during one pulse may be used to determine the charge drop in the capacitors and to determine a configuration of an associated fine tune and/or main Marx generator that would compensate for the charge drop and yield a desired voltage and/or charge for the next pulse. Actual impedance of the load (e.g., tissue) and/or other characteristics, may be determined from, for example, current and voltage readings and used for determining desired pulse parameters for the next pulse. The process may be repeated for additional pulses as long as sufficient charge remains on some of the capacitors. In some applications, an identical pulse in a pulse train may be produced by using a "fresh" set of, for example, main Marx generator capacitors for each pulse. However, in some embodiments, this option may be limited to 800V, 1200V and 1600V pulses.

[00151] Fig. 14b shows a two-pulse, bipolar pulse train waveform generated by a pulse generator according to some embodiments of the present disclosure. In some embodiments, the bipolarity of the pulse train may be initiated using one or more polarity switches. In some embodiments, the bipolar pulse train may deliver a zero net charge, where the pulse train has a first pulse characterized by accumulated positive charge that equals an accumulated negative charge of a second pulse. In some embodiments, a pulse train delivering pulses culminating in zero net charge may be advantageous in some applications, for example, defibrillation shocks delivering zero net charge to a patient's heart may cause less discomfort than other waveforms.

[00152] The charge of Pulse 1 shown in Fig. 14b may be determined by integrating the current, as measured by a current sensor, during Pulse 1. In some embodiments, the charge of Pulse 1 may be determined by measuring the voltage drop and/or the known capacitance. In some embodiments, the charge Pulse 1 may be pre-determined by terminating Pulse 1 at a specific integrated current value or a specific voltage drop. In some embodiments, the charge of Pulse 2 shown in Fig. 14b may be configured to match the charge of Pulse 1, even if the voltages of Pulse 1 and Pulse 2, respectively, are different. Configuring Pulse 2 to have a charge equal to Pulse 1 may be accomplished, according to some embodiments, by terminating Pulse 2 at a specific integrated current value or a specific voltage drop. Furthermore, in some embodiments, Pulse 1 may be terminated when energy delivered by Pulse 1 reaches a predetermined value, and Pulse 2 may be terminated when the charge delivered by Pulse 2 equals the charge delivered by Pulse 1. Alternatively, in some embodiments, one or more parameters of Pulse 1 and Pulse 2 may be different and/or independent of each other.

[00153] Fig. 14c shows a three-pulse, or tri-phase, pulse train waveform generated by a pulse generator according to embodiments of the present disclosure, with the pulse train waveform including a Pulse 1, Pulse 2, and Pulse 3. Each of Pulse 1, Pulse 2 and Pulse 3 may have parameters selected from initial voltage, polarity, duration, tilt, delivered energy, accumulated charge and time between it and adjacent pulses. These parameters may be computed, in some embodiments, based on input provided by a user and/or one or more sensors (e.g., sensors measuring characteristics of the load, sensors measuring characteristics of delivered pulses, etc.) Some or all of these parameters may be different for all or some of the three pulses.

[00154] Fig. 14d shows another pulse train waveform having two bipolar main pulses, namely, Pulse 1 and Pulse 2, and a third, charge-trimming pulse, namely, Pulse 3, generated by a pulse generator according to embodiments of the present disclosure.

[00155] In some embodiments, the parameters of Pulse 1 and Pulse 2 may be configured to deliver a predetermined energy, while Pulse 3 may be configured to ensure that the total accumulated charge delivered by the pulse train is zero, or some other predetermined value. When each of Pulse 1 and Pulse 2 are delivered, a controller tracks the accumulated value of the power or energy delivered by monitoring and/or integrating signals from one or more voltage and/or current sensors (and/or performing some other processing on signals from the various sensors). In some embodiments, the controller may monitor the total charge delivered by Pulse 1 and/or Pulse 2, as explained herein. After Pulse 2 ends, as shown in Fig. 14d, the controller may determine the polarity and one or more parameters of Pulse 3 and deliver it as a third "charge-trimming" pulse that brings the total charge of the pulse train to, for example, zero. Because impedance of the load (e.g., biological tissue) may change during and/or as a result of the delivered pulse train, a charge-trimming pulse like Pulse 3 may be needed. However, in some embodiments, its parameters may not be known before delivering Pulse 1 and/or Pulse 2. Pulse 3 may be of short duration and/or low voltage. In some embodiments, Pulse 3 may be monitored for accumulated charge and/or terminated when the total charge of the pulse train equals zero (or approximately zero). In some embodiments, Pulse 1 and Pulse 2 may be configured to have the same voltage and duration, and Pulse 3 may follow to nullify the total accumulated charge to zero.

[00156] The pulse trains depicted in Figs. 14a-14d are to be viewed as non-limiting and partial examples of pulse trains that the pulse generator embodiments of the present disclosure may deliver. Other pulse shapes and/or pulse trains may be possible and are indeed contemplated within the scope of this disclosure. Similarly, the switch configurations depicted and described herein are to be viewed as non-limiting and partial examples of switch configurations that may be contained within the pulse generator embodiments of the present disclosure. Other switch configurations may be possible and are indeed contemplated within the scope of this disclosure. In some embodiments, the command to terminate a pulse may take into account system response time.

[00157] Furthermore, with current capacitor values, the capacitors are typically not significantly discharged during a single pulse train and especially not during a single pulse in a pulse train. However, if a miniature pulse generator (e.g., an implantable defibrillator) is to be implemented according to the present disclosure, smaller capacitors may have to be selected. In this case, capacitors may be significantly discharged during a single pulse or pulse train and switch configurations may need to be charged between pulses to produce two or more pulses.

[00158] Embodiments of the fine tune and/or main Marx generators disclosed herein may optimize the use of stored energy for delivering HV pulses to a patient's heart. For example, a 400V pulse may be initiated when all switches in a fine tune and/or main Marx generator open. When the voltage drops to 200V, one or more switches may be closed to bring the voltage back to 400V. When the voltage again drops to 200V, one or more other switches may be closed to bring the voltage back to 400V. Finally, when the voltage again drops to 200V, one or more other switches may be closed to bring the voltage back to 400V.

[00159] In some implementations, the devices and systems describes herein, including the pulse generators, may be coupled to multiple electrodes (e.g., 3, 4, or more) with one set of electrodes placed at or near one area of the load, and another set of electrodes (which may commonly share at least one electrode from the first set) placed at another area of the load. Any number of electrode sets may be used in such multiple electrode configurations. In such implementations, some of the pulses generated by the pulse generator (or by the device/system that includes a pulse generator) may be delivered via the first set of electrodes, and some of the other pulses may be delivered via the other set of electrodes. Such electrode configurations may enable a greater coverage of the load than would be possible with only a single set of electrodes. For example, in some embodiments, different parts of a particular pulse train may be delivered via one pair of electrodes of the single pulse generator, and other parts of the particular pulse train may be delivered via another pair of electrodes. Such multi- electrode -pair delivery of the particular pulse train may be performed without having to recharge the pulse generator's capacitors during delivery of the pulse train. Thus, in some embodiments, a device/system that includes a configurable pulse generator may include two or more electrode -pairs, with at least one of a plurality of pulses delivered through one of the two or more electrode-pairs, and at least another of the plurality of pulses delivered through another of the two or more electrode pairs, the plurality of pulse being delivered without having to recharge the plurality of capacitors.

[00160] In some embodiments, two pulse trains may need to be produced and delivered to the load, with the first train being delivered to the load via the first set and the second train to be delivered by the other electrode set. Upon completion of the delivery of the first pulse train, the capacitors of the pulse generator may be recharged, and the configuration of the pulse generators may be reconfigured (to enable delivery of the pulses of the second pulse train) by, for example, controlling the configuration of the capacitors (e.g., through opening and closing of switches electrically connecting the capacitors to each other and to the electrodes) using a controller. Once the capacitors are charged and the required configuration of the pulse generator properly established, the power supply may be electrically disconnected from the pulse generator, and delivery of the first pulse in the second pulse train may be commenced. In some embodiments, delivery of pulses may alternate from one set of electrodes to another (i.e., a first pulse of a pulse train may be delivered through one set of electrodes, and a second pulse of the pulse train may be delivered via a second electrode set).

[00161] In some embodiments, systems may be provided that include two or more pulse generators that can each be coupled to a load via respective electrodes of the two or more pulse generators. Like with the multiple electrode sets implementations described above, use of multiple pulse generators enables delivery of pulse trains to multiple locations at the load to provide a more optimal distribution of the energy delivered to the load. In some embodiments, delivery of pulses from one pulse generator may proceed only upon completion of pulse delivery by a first pulse generator. In some embodiments, delivery of pulses may alternate between the two or more pulse generators (e.g., one pulse is delivered from one pulse generator, and then the next pulse to be delivered by that generator can only be delivered when a first pulse from the second generator has been delivered). In situations where multiple simultaneous pulses need to be delivered to the load, use of multiple pulse generator devices may be required, with two or more of such devices simultaneously delivering pulses to the load via their respective electrodes.

[00162] With reference to Fig. 15, a flowchart of an example procedure 1500 to configure a pulse generator for delivery of electrical pulses is shown. The procedure 1500 includes determining 1510 one or more attributes associated with one or more electrical pulses to be applied to a load (e.g., target cardiac tissue of a patient) through electrodes. For example, the attributes of the pulses may have been predetermined (e.g., by a remote user or computing device) and provided as input to a device including a pulse generator (such as the pulse generator 100 depicted in Fig. la). Such input can be processed by a controller (such as the controller 110 of Fig. la) to determine control signal to configure the pulse generator to deliver the required pulses. In some embodiments, determination of the pulse attributes may be based on, for example, data measured by one or more sensors with respect to the load characteristics, and data measured by one or more sensors with respect to pulse characteristics.

[00163] Having determined attributes of the pulses to be delivered to a load (e.g. cardiac tissue of a patient), a dynamically configurable pulse generator to generate the one or more electrical pulses with the determined one or more attributes is configured 1520. The dynamically configurable pulse generator (e.g., a Marx generator with multiple chargeable capacitors that can be controllably arranged) is adapted to be reconfigured after generating at least one of the one or more electrical pulses. For example, if a pulse train of two or more pulses is desired, with the first pulse having a different amplitude, shape and/or duration from another of the pulses, upon delivery of the first pulse, the pulse generator may need to be reconfigured (e.g., by changing the electrical connections of the generator's capacitors) to enable the delivery of the other pulses having different attributes then the pulse just delivered. Thus, in some embodiments, one more electrical pulses may include a pulse train with each of the pulses in the train associated with a corresponding set of attributes, and configuring the pulse generator may include, in such embodiments, reconfiguring the pulse generator after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated.

[00164] In some implementations the procedure 1500 may include measuring at least one characteristic associated with a load (e.g., target cardiac tissue of a patient), and, in such implementations, determining the one or more attributes associated with the one or more electrical pulses may include determining the one or more attributes based, at least in part, on the measured at least one characteristic.

[00165] Various embodiments of the devices and systems described herein may be implemented in hardware using, for example, components such as application specific integrated circuits ("ASICs"), or field programmable gate arrays ("FPGAs"). Implementation of a hardware state machine capable of performing the functions described herein may also be used. Various embodiments may also be implemented using a combination of both hardware and software.

[00166] The various illustrative logical blocks, modules, circuits, and methods described in connection with the above described figures and the embodiments disclosed herein can often be implemented as electronic hardware, computer software, or combinations of both.

[00167] Moreover, the various illustrative logical blocks, modules, and methods described in connection with the embodiments disclosed herein can be implemented or performed with a general purpose processor, a digital signal processor ("DSP"), an ASIC, FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general- purpose processor can be a microprocessor, but in the alternative, the processor can be any processor, controller, microcontroller, or state machine. A processor can also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[00168] Additionally, the methods/procedures described in connection with the embodiments disclosed herein can be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium including a network storage medium. An exemplary storage medium can be coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium can be integral to the processor. The processor and the storage medium can also reside in an ASIC.

[00169] The embodiments set forth in the foregoing description do not represent all embodiments consistent with the subject matter described herein. It is evident that many alternatives, modifications and variations of such embodiments will be apparent to those skilled in the art. As noted elsewhere, these embodiments have been described for illustrative purposes only and are not intended to be limiting. Thus, other embodiments are possible and are covered by the disclosure, which will be apparent from the teachings contained herein. The breadth and scope of the disclosure should not be limited by any of the above-described embodiments but should be defined only in accordance with claims supported by the present disclosure and their equivalents. Moreover, embodiments of the subject disclosure may include methods, systems and devices which may further include any and all elements from any other disclosed methods, systems, and devices; that is, elements from one or another of the disclosed embodiments may be interchangeable with elements from another of the disclosed embodiments. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to any of the disclosed embodiments.

[00170] A number of implementations of the invention have been described.

Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A cardiac treatment device comprising:

a dynamically configurable pulse generator to generate one or more electrical pulses with one or more adjustable attributes, the one or more electrical pulses to be applied to target cardiac tissue of a patient through electrodes, the dynamically configurable pulse generator operable to be reconfigured after generating at least one of the one or more electrical pulses; and

a controller to dynamically configure the pulse generator to generate the one or more

electrical pulses with the one or more adjustable attributes.

2. The device of claim 1, wherein the one more electrical pulses include a pulse train with each of the pulses in the train associated with a corresponding set of attributes;

wherein the pulse generator is adapted to be reconfigured after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated.

3. The device of claim 1, wherein the pulse generator comprises:

a Marx generator including a plurality of capacitors configured to be controllably charged with current from an energy source, and to be adjustably electrically coupled to the electrodes in accordance with signals generated by the controller adapted to dynamically configure the Marx generator to generate the one or more electrical pulses.

4. The device of claim 3, wherein at least some of the plurality of capacitors are charged before a first of the one or more electrical pulses is generated, and wherein the energy source is electrically uncoupled from the plurality of capacitors until a last of the one or more electrical pulses has been generated.

5. The device of claim 3, wherein the Marx generator further comprises one or more

switches controllable by the controller, the one or more switches facilitating selectively establishing electrical paths between at least some of the plurality of capacitors and the electrodes.

6. The device of claim 5, wherein the one or more switches include at least one insulated gate bipolar transistor (IGBT) switch.

7. The device of claim 5, wherein the one or more switches include at least one polarity

switch to reverse voltage polarity of at least one of the one or more electrical pulses generated by the Marx generator.

8. The device of claim 5, wherein the one or more switches include at least one crowbar switch to perform a fast discharge of the plurality of capacitors of the Marx generator.

9. The device of claim 3, further comprising one or more diodes to block electrical discharge not directed to the target cardiac tissue.

10. The device of claim 3, wherein the Marx generator comprises:

a configurable fine tune Marx generator with fine tune capacitors configured to be arranged to produce a plurality of possible voltage levels in a first range; and

a configurable main Marx generator with main capacitors configured to be arranged to

produce a plurality of possible incremental voltage levels that are each separated by a value of at least the first range.

11. The device of claim 10, wherein an initial voltage level of the Marx generator available for delivery of pulses is equal to a sum of a voltage from the first range produced by the fine tune Marx generator and a voltage produced by the main Marx generator.

12. The device of claim 3, wherein the plurality of capacitors configured to be controllably charged with current from an energy source, and to be adjustably electrically coupled to the electrodes, includes:

at least a first capacitor controllably coupled in a parallel arrangement to at least another first capacitor, and at least a second capacitor controllably coupled in a series arrangement to at least another second capacitor.

13. The device of claim 3, further comprising two or more electrode-pairs, wherein the pulse generator is configured to generate a pulse train comprising a plurality of pulses, with at least one of the plurality of pulses delivered through one of the two or more electrode -pairs, and at least another of the plurality of pulses delivered through another of the two or more electrode pairs, the plurality of pulses being delivered without having to recharge the plurality of capacitors.

14. The device of claim 3, wherein the Marx generator is configured for fast charging of at least one of the plurality of capacitors using one or more of a switch and a diode to implement charging resistance electrically coupled to the at least one of the plurality of capacitors.

15. The device of claim 3, wherein at least some of the capacitors are arranged to enable at least one of the generated one or more pulses to have a varying tilt.

16. The device of claim 1, further comprising:

a feedback monitor including at least one generator sensor to measure values of electrical characteristics of one or more of: the one or more generated electrical pulses, and electrical characteristics in at least one location of electrical paths established in the dynamically configured pulse generator;

wherein the controller to dynamically configure the pulse generator is adapted to configure the pulse generator based on the values of the electrical characteristics measured by the at least one generator sensor of the feedback monitor.

17. The device of claim 16, further comprising a main switch configured to be opened to terminate the flow of the one or more pulses in response to a comparison of the values of the electrical characteristics measured by the at least one generator sensor and respective one or more predetermined threshold values.

18. The device of claim 1, further comprising:

at least one sensor to measure at least one characteristic associated with the target cardiac tissue of the patient;

wherein the pulse generator is adapted to generate the one or more electrical pulses with the one or more attributes determined based, at least in part, on the measured at least one characteristic associated with the target cardiac tissue.

19. The device of claim 18, wherein the at least one sensor to measure the at least one characteristic associated with the target cardiac tissue of the patient is configured to: measure electrical impedance of the target cardiac tissue.

20. The device of claim 19, wherein the at least one sensor configured to measure the

electrical impedance of the target cardiac tissue is configured to determine the electrical impedance of the target cardiac tissue substantially in real-time by dividing data representative of a measured real-time voltage applied to the target cardiac tissue by data representative of a measured real-time current applied to the target cardiac tissue.

21. The device of claim 20, wherein the pulse generator is further configured to terminate the one or more pulses based, at least in part, on the determined substantially real-time electrical impedance.

22. The device of claim 19, wherein the device further comprises:

an impedance measurement relay to disconnect the at least one sensor configured to measure the electrical impedance of the target cardiac tissue from a circuitry through which the generated one or more pulses are delivered.

23. The device of claim 19, wherein the controller is adapted to dynamically configure the pulse generator to generate the one or more pulses with the one or more attributes determined based, at least in part, on the measured electrical impedance of the target cardiac tissue.

24. The device of claim 1, wherein the one or more attributes of the one more electrical pulses to be generated include one or more of: initial voltage of the one or more pulses, end voltage of the one or more pulses, voltage tilt of the one or more pulses representative of a difference between the initial voltage and the end voltage of the one or more pulses as a percentage of the initial voltage, pulse duration of the one or more pulses, and interval between pulses in the one or more pulses.

25. The device of claim 1, wherein the pulse generator is configured to terminate delivery of the one or more pulses in response to one or more of: sensing over current condition, sensing that pulse current is too low, sensing over voltage condition, sensing that pulse voltage is too low, sensing that the pulse voltage is decaying too fast, sensing that the pulse voltage is decaying too slowly, and sensing unusual energy reading.

26. A method comprising:

determining one or more attributes associated with one or more electrical pulses to be applied to target cardiac tissue of a patient through electrodes; and

configuring a dynamically configurable pulse generator to generate the one or more electrical pulses with the determined one or more attributes, the dynamically configurable pulse generator operable to be reconfigured after generating at least one of the one or more electrical pulses.

27. The method of claim 26, wherein the one more electrical pulses include a pulse train with each of the pulses in the train associated with a corresponding set of attributes;

wherein configuring the pulse generator comprises:

reconfiguring the pulse generator after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated.

28. The method of claim 26, wherein configuring the pulse generator to generate the one or more electrical pulses with the determined one or more attributes comprises:

configuring a Marx generator including a plurality of capacitors configured to be controllably charged, and to be adjustably electrically coupled to the electrodes, to generate the one or more electrical pulses.

29. The method device of claim 28, wherein configuring the Marx generator comprises: configuring at least one of the one or more switches to one of open and close positions to selectively establish electrical paths between at least some of the plurality of capacitors and the electrodes.

30. The method of claim 26, further comprising:

measuring at least one characteristic associated with the target cardiac tissue of the patient; wherein determining the one or more attributes associated with the one or more electrical pulses comprises determining the one or more attributes based, at least in part, on the measured at least one characteristic.

31. The method of claim 30, wherein measuring the at least one characteristic associated with the target cardiac tissue of the patient comprises:

measuring electrical impedance of the target cardiac tissue.

32. The method of claim 31 , wherein determining the one or more attributes comprises: determining the one or more attributes based, at least in part, on the measured electrical impedance of the target cardiac tissue.

33. The method of claim 26, wherein the one or more attributes of the one more electrical pulses to be generated include one or more of: initial voltage of the one or more pulses, end voltage of the one or more pulses, voltage tilt of the one or more pulses representative of a difference between the initial voltage and the end voltage of the one or more pulses as a percentage of the initial voltage, pulse duration of the one or more pulses, and interval between pulses in the one or more pulses.

34. A system comprising:

a dynamically configurable pulse generator to generate one or more electrical pulses with determined one or more adjustable attributes, the one or more electrical pulses to be applied to target cardiac tissue of a patient through electrodes, the dynamically configurable pulse generator operable to be reconfigured after generating at least one of the one or more electrical pulses;

an energy source coupled to the pulse generator to power and charge the pulse generator; and a controller to dynamically configure the pulse generator to generate the one or more

electrical pulses with the determined one or more attributes.

35. The system of claim 34, wherein the one more electrical pulses include a pulse train with each of the pulses in the train associated with a corresponding set of attributes;

wherein the pulse generator is adapted to be reconfigured after generating one pulse from the pulse train to cause a next pulse in the pulse train having an associated set of attributes to be generated.

36. The system of claim 34, wherein the pulse generator comprises: a Marx generator including a plurality of capacitors configured to be controllably charged with current from the energy source, and to be adjustably electrically coupled to the electrodes in accordance with signals generated by the controller adapted to dynamically configure the Marx generator to generate the one or more electrical pulses.

37. The system of claim 34, further comprising:

at least one sensor to measure at least one characteristic associated with the target cardiac tissue of the patient;

wherein the pulse generator is adapted to generate the one or more electrical pulses with the one or more attributes determined based, at least in part, on the measured at least one characteristic associated with the target cardiac tissue.

38. The system of claim 34, further comprising:

at least one other pulse generator to generate additional one or more electrical pulses with determined one or more adjustable attributes, the additional one or more electrical pulses to be applied to the target cardiac tissue of the patient through at least one other set of electrodes.

39. A device comprising:

a dynamically configurable pulse generator to generate one or more electrical pulses with one or more adjustable attributes, the one or more electrical pulses to be applied to a load through electrodes, the dynamically configurable pulse generator operable to be reconfigured after generating at least one of the one or more electrical pulses; and a controller to dynamically configure the pulse generator to generate the one or more

electrical pulses with the one or more adjustable attributes.