Single frequency switched mode power supply generator with phase shifter

Abstract

To provide a power generator for use with a medical tool used to perform a medical ablation procedure.SOLUTION: The power generator comprises a power supply configured to generate a DC voltage, a phase shifter configured to shift signal transmission phase angles, and multiple switched-mode amplifiers each configured to convert the DC voltage received from the power supply to an AC voltage signal. The power generator also comprises a processor configured to control a phase shift of each AC voltage signal converted by the switched-mode amplifiers and an amplitude of each AC voltage signal converted by the switched-mode amplifiers. Each AC voltage signal is provided to one of multiple ablation electrodes of a medical tool.SELECTED DRAWING: Figure 1

Description

[Background technology]

[0001] Conventional ablation methods and systems (e.g., radio frequency (RF) catheter ablation) are used to ablate dysfunctional tissue portions, such as tissue in the heart, lungs, ears, nose, throat, or other organs of a patient's anatomy. For example, during a medical procedure such as an RF catheter ablation procedure, a catheter is typically inserted through an incision in the skin and guided to the organ where the catheter is used to create an ablation lesion in the organ tissue.

[0002] The position of a medical tool in three-dimensional (3D) space within a patient's anatomy is determined using electromagnetic navigation, which includes an electromagnetic emitter and an electromagnetic sensor on the tool to determine the tool's position. Based on the determined position, the patient's anatomical information is displayed to the medical practitioner. A dynamic map of the patient's anatomy (e.g., an organ) is created to facilitate accurate determination of a region for ablation. By viewing this map, a target ablation site (i.e., a region of interest (ROI)) of the organ is identified. Based on the identified ablation site, an ablation procedure (including one or more ablations) is performed on the organ. [Brief explanation of the drawings]

[0003] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, in which: [Figure 1] FIG. 1 illustrates an exemplary medical system for navigating a tool in 3D space, according to embodiments disclosed herein. [Figure 2] FIG. 1 is a diagram of components of an exemplary electromagnetic navigation system for use with embodiments described herein. [Figure 3] FIG. 1 is a diagram of components of a medical tool including a switched mode power supply generator operating at signal frequencies that can be used to implement features of the present disclosure. [Figure 4]FIG. 1 is a diagram of components of a medical tool including a class D inverter power amplifier that can be used to implement features of the present disclosure. [Figure 5] FIG. 1 is a flow diagram illustrating an exemplary method for controlling power delivered for a medical ablation procedure. DETAILED DESCRIPTION OF THE INVENTION

[0004] The methods and systems used to identify ablation sites and perform ablation procedures are time-consuming (e.g., several hours) and rely on medical personnel with specific expertise and experience (which typically require significant training hours). Successful treatment depends on accurate identification of the ablation site and accurate assessment of the ablation performed on the organ.

[0005] Typically, ablation is performed by applying RF energy to an organ through multiple electrodes of a medical tool, such as a catheter. A radio frequency (RF) generator is used to power the electrodes of the medical tool for ablation.

[0006] Conventional RF generators include a linear power supply that applies an AC voltage to a transformer to change (e.g., reduce) the voltage before applying it to a regulator to regulate the voltage. The components of these conventional linear power supplies (e.g., the transformer and regulator circuitry) used to regulate the voltage are relatively large and generate more heat, resulting in lower energy efficiency. For example, conventional linear power generators have limited power yield (e.g., 25 watts of RF energy) and require a large amount of power for ablation.

[0007] Additionally, in the case of multi-catheter ablation, conventional RF generators control the power delivered to each electrode by driving the electrodes with signals having different frequencies, resulting in intermodulation distortion (IMD). IMD occurs when multiple signals of different frequencies mix together, typically forming additional signals at frequencies that are not harmonic frequencies of any of the signals. Therefore, IMD can cause the ablation signal to interfere with other signals, such as electrocardiogram (ECG) signals.

[0008] The present application provides a medical tool, such as a catheter, that includes a switch-mode power supply generator that operates at a single frequency. The power generator includes multiple switch-mode amplifiers, each electrically connected to one of multiple ablation electrodes of the medical tool, such as a catheter. In contrast to conventional linear power supply RF generators, the switch-mode power supply RF generator directly converts AC power to a DC voltage without using a transformer. Therefore, the switch-mode power supply generator is smaller and more efficient (e.g., has a higher power conversion ratio) than conventional linear power supply generators used for RF ablation.

[0009] Additionally, the switch mode power supply generator disclosed herein controls the power supplied to the electrodes by the applied voltage and phase shift. That is, the amplitude is controlled for signals output to each of the electrodes with the same frequency but different phase shift to control the power obtained by each electrode. Because the power is controlled using a single frequency, there is no IMD and the ablation signal does not interfere with other signals.

[0010] This application discloses a power generator for use with a medical tool used to perform medical ablation procedures. The power generator includes a power source configured to generate a DC voltage, a phase shifter configured to shift a signal transmission phase angle, and multiple switch-mode amplifiers each configured to convert the DC voltage received from the power source into an AC voltage signal. The power generator also includes a processor configured to control the phase shift of each AC voltage signal converted by the switch-mode amplifier and the amplitude of each AC voltage signal converted by the switch-mode amplifier.

[0011] This application discloses a system for performing a medical ablation procedure. The system includes a medical tool including a plurality of electrodes used to apply radio frequency (RF) energy to ablate tissue and a power generator including a power source configured to generate a DC voltage. The power generator includes a power source configured to generate the DC voltage, a phase shifter configured to shift a signal transmission phase angle, and a plurality of switch-mode amplifiers each electrically connected to a corresponding one of the electrodes and each configured to convert the DC voltage received from the power source into an AC voltage signal provided to the corresponding electrode. The power generator also includes a processor configured to control the power obtained by each electrode by controlling the phase shift of each AC voltage signal converted by the switch-mode amplifier and controlling the amplitude of each AC voltage signal converted by the switch-mode amplifier.

[0012] The present application discloses a method for controlling power supplied for a medical ablation procedure, the method including: providing a DC voltage, converting the DC voltage into a corresponding AC voltage signal by each of a plurality of switch-mode amplifiers, controlling a phase shift of each AC voltage signal converted by the switch-mode amplifier, and controlling an amplitude of each AC voltage signal converted by the switch-mode amplifier.

[0013] Referring now to FIG. 1 , a diagram of an example medical system 20 is shown that can be used to generate and display information 52 (e.g., charts, anatomical models of a portion of a patient, and signal information). A tool (i.e., a medical tool), such as tool 22, may be any tool including catheters and sheaths (e.g., steerable and deflectable sheaths) used for diagnostic or therapeutic procedures, such as for mapping electrical potentials within a heart 26 of a patient 28. Alternatively, the tool may be used for other therapeutic and / or diagnostic purposes in different anatomical parts, such as within the heart, lungs, or other body organs (e.g., ear, nose, and throat (ENT)), mutatis mutandis. Tools may include, for example, probes, catheters, cutting tools, and aspiration devices.

[0014] An operator 30 can insert the tool 22 into a portion of the patient's anatomy (e.g., the vascular system of the patient 28) so that a tip 56 of the tool 22 enters a cavity of the heart 26. The control console 24 can use magnetic position sensing to determine the position coordinates of the tool (e.g., the coordinates of the tip 56) within 3D space inside the heart 26. As described in more detail below, magnetic position sensing is used to determine the position of both the catheter and sheath of the tool 22 within 3D space. To determine the position coordinates, a driver circuit 34 within the control console 24 can drive a magnetic field generator 36 via a connector 44 to generate a magnetic field within the anatomy of the patient 28.

[0015] The magnetic field generator 36 includes one or more emitter coils (not shown in FIG. 1 ) positioned at known locations external to the patient 28 and configured to generate a magnetic field within a predetermined working volume that includes a target portion of the patient's anatomy. Each emitter coil is driven at a different frequency and emits a constant magnetic field in 3D space. For example, in the exemplary medical system 20 shown in FIG. 1 , one or more emitter coils may be positioned under the torso of the patient 28, each configured to generate a magnetic field within a predetermined working volume that includes the patient's heart 26.

[0016] One or more electromagnetic sensors (i.e., magnetic field position sensors) 38 are disposed on the catheter of tool 22 that generate electrical signals based on the amplitude and phase of the magnetic field to determine the position of the catheter in 3D space. As described in more detail below, three separate electromagnetic sensors 38 are also disposed on the sheath of tool 22 to precisely determine the position of the sheath using electromagnetic navigation.

[0017] The signals may be wirelessly communicated to the control console 24 by a wireless communication interface (e.g., interface 312 shown in FIG. 3 ) in the tool 22 and communicated with a corresponding input / output (I / O) interface 42 in the control console 24. The wireless communication interface 312 and the I / O interface 42 may operate according to any suitable wireless communication standard known in the art, such as infrared (IR), radio frequency (RF), Bluetooth, one of the IEEE 802.11 family of standards (e.g., Wi-Fi), or the HiperLAN standard. The body surface electrodes 46 may include one or more wireless sensor nodes integrated on a flexible substrate. The one or more wireless sensor nodes may include a wireless transmit / receive unit (WTRU), a wireless link, and a small secondary battery to enable local digital signal processing, as described in more detail below.

[0018] The I / O interface 42 may enable the control console 24 to interface with the tools 22, the body surface electrodes 46, and position sensors (not shown). Based on the electrical impulses received from the body surface electrodes 46 and the electrical signals received from the tools 22 using the I / O interface 42 and other components of the medical system 20, the signal processor 40 may determine the position of the catheter and sheath of the tools 22 in 3D space and generate display information 52, which may be shown on the display 50.

[0019] The signal processor 40 is configured to process the signals to determine position coordinates, including both position and orientation coordinates, of the catheter and sheath of the tool 22 in 3D space. The magnetic field position sensor 38 sends signals to the control console 24 indicating the position coordinates of the tool 22 in 3D space (e.g., the position coordinates of the catheter and sheath of the tool 22 in 3D space).

[0020] The signal processor 40 may be included in a general-purpose computer having suitable front-end and interface circuitry for receiving signals from the tool 22 and controlling other components of the control console 24. The signal processor 40 may be programmed using software to perform the functions described herein. The software may be downloaded to the control console 24 in electronic form, for example, over a network, or may be provided on a non-transitory tangible medium, such as an optical, magnetic, or electronic storage medium. Alternatively, some or all of the functions of the signal processor 40 may be performed by dedicated or programmable digital hardware components.

[0021] In the embodiment shown in FIG. 1 , the control console 24 is connected to the body surface electrodes 46 via a cable 44, and each of the body surface electrodes 46 is attached to the patient 28 using a patch (e.g., shown in FIG. 1 as a circle around the electrode 46) that adheres to the patient's skin. In addition to or instead of a patch, the body surface electrodes 46 may also be positioned on the patient using an article worn by the patient 28 that includes the body surface electrodes 46 and may also include one or more position sensors (not shown) that indicate the position of the worn article. For example, the body surface electrodes 46 may be embedded in a vest configured to be worn by the patient 28. During surgery, the body surface electrodes 46 help provide the position of a tool (e.g., a catheter) in 3D space by detecting electrical impulses caused by polarization and depolarization of cardiac tissue and transmitting the information to the control console 24 via the cable 44. The body surface electrodes 46 may also be equipped with a magnetic position tracking device, which may help identify and track the patient 28's respiratory cycle.

[0022] Additionally or alternatively, the tools 22, body surface electrodes 46, and other sensors (not shown) can communicate with the control console 24 and each other via a wireless interface. For example, a wireless catheter that is not physically connected to a signal processing and / or computing device can communicate with the control console 24. For example, a transceiver is attached to the catheter and communicates with the signal processing and / or computing device using a wireless communication method, such as IR transmission, RF transmission, Bluetooth transmission, or acoustic transmission.

[0023] During a diagnostic procedure, the signal processor 40 may present the displayed information 52 and store data representing the information 52 in memory 58. The memory 58 may include any suitable volatile and / or non-volatile memory, such as random access memory or a hard disk drive. The operator 30 may be able to manipulate the displayed information 52 using one or more input devices 59. Alternatively, the medical system 20 may include a second operator who operates the control console 24 while the operator 30 operates the tool 22. It should be noted that the configuration shown in FIG. 1 is exemplary. Any suitable configuration of the medical system 20 may be used and implemented.

[0024] FIG. 2 is a block diagram illustrating example components of a medical system 200 for use with embodiments described herein. As shown in FIG. 2, the system 200 includes a medical tool 201, a processing unit 204, a display unit 206, and a memory 212. The medical tool 201 includes a catheter 202 and a sheath 220. The catheter 202 is, for example, an ablation catheter used to ablate a portion (e.g., tissue) within a patient's anatomy. The sheath 220 is, for example, steerable and deflectable to facilitate catheter access, stability, and tissue contact at a target site within the patient's anatomy. For example, during a procedure, the catheter 202 is guided within the patient's anatomy (e.g., via a blood vessel) to a target location (e.g., the heart) through the steerable and deflectable sheath 220.

[0025] 2, processing unit 204, display device 206, and memory 212 are part of an exemplary computing device 214. In some embodiments, display device 206 may be separate from computing device 214. Computing device 214 may further include an I / O interface, such as I / O interface 42 of FIG.

[0026] 2, the example catheter 202 includes one or more sensors 216, including, for example, magnetic field position sensors (e.g., sensors 38 of FIG. 1) that provide position signals indicative of the 3D position coordinates of the catheter 202. Similarly, the example sheath 220 includes one or more sensors 218, including, for example, magnetic field position sensors that provide position signals indicative of the 3D position coordinates of the sheath 220. In some processes, as shown in the example system 200, one or more additional sensors 210 separate from the catheter 202 are used to provide further position signals. In some embodiments, the catheter 202 also includes catheter electrodes 208 for mapping cardiac electrical potentials.

[0027] The sensors 216 (and 218) may also include, for example, position sensors, pressure or force sensors, temperature sensors, impedance sensors, or other sensors that provide ablation parameter signals indicative of ablation parameters during ablation of tissue of an organ. During an ablation procedure, the RF generator 230 delivers radio frequency electrical energy through the catheter 202 to ablate tissue at the location where the catheter 202 is engaged. The sensors 216, 218 sense ablation parameters (e.g., positional stability, temperature, ablation time, ablation power, and ablation impedance of the catheter 202 or sheath 220) during the ablation procedure. The catheter 202 or sheath 220 may be in wired or wireless communication with the processing unit 204 to communicate information acquired by the sensors 216, 218.

[0028] The location signals are processed as location data and stored, for example, in memory 212. The processing unit 204 receives (e.g., reads from memory) the location data corresponding to the location signals and generates mapping information from the location data to display one or more maps of the organ being ablated. The ablation parameter signals are processed as ablation parameter data and stored, for example, in memory 212.

[0029] The processing unit 204 receives ablation parameter data corresponding to the ablation parameter signal and generates first object information from the ablation parameter data for displaying a first geometric object having a first dimension representing an estimated depth of ablation of the organ, and further receives second object information from the ablation parameter data for displaying a second geometric object having a second dimension representing an estimated width of ablation of the organ simultaneously with the first geometric object.

[0030] That is, processing unit 204 receives ablation parameter data corresponding to ablation parameter signals acquired during the ablation procedure (e.g., via one or more sensors 216), determines an estimated depth and width of the ablation from the ablation parameter data, and generates object information from the ablation parameter data to display a geometric object visually representing the estimated depth and width of the ablation. For example, using the ablation parameter data, processing unit 204 executes a plurality of program instructions (e.g., a lesion estimation and assessment algorithm) to determine the estimated depth and width of the ablation. Processing unit 204 then generates first object information for displaying a first geometric object having a first dimension representing the estimated depth of the cardiac ablation. Processing unit 204 further generates second object information for displaying a second geometric object having a second dimension representing the estimated width of the cardiac ablation simultaneously with the first geometric object.

[0031] The processing unit 204 can further execute program instructions using the ablation parameter data to generate blood flow information for displaying indicia on a map of the organ to visually represent portions of organ tissue that are not in contact during the ablation procedure. For example, during an ablation procedure, an ablation parameter signal can be obtained via the sensor 216 that indicates whether the catheter 202 is in contact with organ tissue in a portion of the heart. The ablation parameter signal can include, for example, information identifying the position of the catheter in 3D space at a particular time, information identifying the force applied by the catheter, impedance information, and other information indicative of whether the catheter 202 is in contact with organ tissue in a portion of the organ.

[0032] The processing unit 204 processes the ablation parameter signals as ablation parameter data and uses the ablation parameter data to determine whether the catheter 202 is in contact with organ tissue in the portion of the organ. If it is determined that there is no contact between the ablation device and cardiac tissue in the portion of the organ, the processing unit 204 generates blood index information indicative of blood ablation (as opposed to ablation of organ tissue).

[0033] The processing unit 204 uses the mapping information to drive the display unit 206 to display a map of the organ on the display unit 206. The processing unit 204 further uses the first object information and the second object information to drive the display unit 206 to display the first and second geometric objects and the determined blood indices (if any) on the display unit 206.

[0034] The display device 206 may include one or more displays, each configured to display one or more maps of an organ. For example, the display device 206 is configured to display a map representing the spatiotemporal expression of an organ (e.g., the heart) along with a geometric object representing the estimated ablation depth and width. The display device 206 may be in wired or wireless communication with the processing device 204. In some embodiments, the display device may be separate from the computing device 214.

[0035] Memory 212 may include, for example, volatile and non-volatile memory, such as random access memory (RAM), dynamic RAM, or cache. Memory 212 may also include storage devices, such as, for example, fixed storage devices (e.g., hard disk drives and solid state drives) and removable storage devices (e.g., optical disks and flash drives).

[0036] 3, the system 200 also includes a switched-mode power supply generator 230. The generator 230 is in communication (e.g., wired or wireless communication) with, for example, the computing device 214 (e.g., the processing unit 204 of the computing device 214). The generator 230 is configured to supply power to each of the electrodes 208 to perform ablation. The generator 230 is described in more detail below with reference to FIG. 3.

[0037] 3 is a diagram of components of an exemplary medical system 300 for use during an ablation procedure. As shown in FIG. 3, the medical system 300 includes a switch-mode power supply generator 230 and a catheter 202. The switch-mode power supply generator 230 includes a power source (e.g., a battery) 302, a processor 304, a phase shifter 306, which may be implemented as hardware (e.g., a voltage-controlled phase shifter), software, or a combination of hardware and software, for shifting the transmission phase angle of a signal, and amplifiers 308. Each of the amplifiers 308 is electrically connected to one of the electrodes 208 of the catheter 202.

[0038] The processor 304 is configured to control the amount of power obtained by each electrode 208 via the phase shifter 306 and amplifier 308. The processor 304 communicates with each amplifier 308 to control the amplitude of the output signal and the phase at which the signal is provided to each electrode 208. The signals for each electrode 208 use the same frequency but are transmitted at different phases. That is, the processor 304 controls the phase shift of the various signals so that each signal to one of the electrodes is identified through a corresponding phase. For example, if the catheter 202 includes ten electrodes, ten different signals would use the same frequency (e.g., 480 kHz) but be transmitted at different phases. Because power is controlled using a single frequency, there is no intermodulation and the ablation signals do not interfere with the ECG signals.

[0039] Figure 4 is a diagram illustrating exemplary components of the amplifier 308 shown in Figure 3. As shown in Figure 4, the amplifier 400 includes a buck-boost converter 402, two pairs of N-channel metal-oxide-semiconductor field-effect (MOSFET) transistors 404, and a filter 408.

[0040] The buck-boost converter 402 is a DC-DC power converter that is controlled by the processor 304 to increase or decrease the input DC voltage to facilitate power control. The buck-boost converter 402 receives a DC voltage signal from the power supply 302 and adjusts the DC voltage provided to the MOSFET transistor 404.

[0041] An N-channel MOSFET transistor 404 is controlled by the processor 304 to switch between different states to convert the DC signal into amplitude pulses. These pulses are amplified through a transformer 405 to provide a digital AC voltage signal 406 in the form of a square wave (e.g., at a frequency of 480 kHz).

[0042] While the transistor 404 shown in FIG. 4 includes two pairs of N-channel MOSFET transistors, the number and type of transistors shown in FIG. 4 are merely exemplary. The amplifier may also include other types of semiconductor or switching components to implement features of the present disclosure. The transformer 405 shown in FIG. 4 includes a turns ratio (number of primary windings Np / number of secondary windings Ns) equal to 0.5. The turns ratio is merely exemplary. The amplifier may include transformers with various turns ratios to implement features disclosed herein. Additionally, while the example of FIG. 4 describes MOSFET transistors, IGBT transistors may be utilized in accordance with the present teachings.

[0043] Filter 408 is, for example, a low-pass filter configured to convert AC voltage signal 406 into an analog AC voltage signal 410 that is delivered to one of the electrodes 208 shown in Figure 3. As shown in Figure 4, square wave AC voltage signal 406 having a frequency of 480 kHz is converted into an analog sinusoidal AC voltage signal 410 having a frequency of 480 kHz, which is delivered to one of the electrodes 208. Filter 408 is, for example, a low-pass filter such as a Butterworth filter, and may include inductors, capacitors, or other electrical components that can be used to attenuate high frequency switching components and pass a frequency band (e.g., a band that includes 480 kHz).

[0044] Because the switched-mode power supply RF generator 230 includes multiple switched-mode amplifiers 308, the switched-mode power supply generator 308 is smaller and more efficient (e.g., has a higher power conversion ratio) than conventional linear power supply generators used for RF ablation.

[0045] Additionally, because the switched mode power supply RF generator 230 controls the power delivery to the electrodes through an applied voltage and phase shift, the power delivered to each of the electrodes 208 is controlled using a single frequency. Thus, the power signal provided to each of the electrodes 208 does not interfere with other signals (e.g., ECG signals) because the IMD present in conventional power generators is avoided.

[0046] It should be noted that although a switch mode amplifier 308 is shown in Figure 3, alternative embodiments may utilize one or more linear power amplifiers. Such operational amplifiers are well known to those skilled in the art.

[0047] FIG. 5 is a flow diagram illustrating an exemplary method 500 for controlling power delivered for a medical ablation procedure.

[0048] As indicated in block 502, the method 500 includes providing a DC voltage, for example, via a battery in an RF switch mode power supply generator.

[0049] As indicated at block 504, the method 500 includes converting a DC voltage into a corresponding AC voltage signal via each of a plurality of switch-mode amplifiers.

[0050] As indicated at block 506, the method 500 includes controlling the phase shift and amplitude of each AC voltage signal converted by the switch-mode amplifier.

[0051] The method can be implemented in a general-purpose computer, processor, or processor core. Suitable processors include, by way of example, a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with a DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), and / or a state machine. Such a processor can be manufactured by configuring a manufacturing process using the results of processed hardware description language (HDL) instructions and other intermediate data, such as a netlist (such instructions can be stored on a computer-readable medium). The result of such processing can be a mask work, which is then used in a semiconductor manufacturing process to produce a processor implementing features of the present disclosure.

[0052] The methods or flow diagrams provided herein may be implemented in a computer program, software, or firmware embodied in a non-transitory computer-readable storage medium for execution by a general-purpose computer or processor. Examples of non-transitory computer-readable storage media include read only memory (ROM), random access memory (RAM), registers, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks and digital versatile disks (DVDs).

[0053] It should be understood that many variations are possible based on the disclosure herein, and although features and elements are described above in particular combinations, each feature or element may be used alone without other features and elements, or in various combinations with other features and elements, with or without other features and elements.

[0054] [Embodiment] (1) A power generator for use with a medical tool used to perform a medical ablation procedure, comprising: a power supply configured to generate a DC voltage; a phase shifter configured to shift a signal transmission phase angle; a plurality of switch-mode amplifiers each configured to convert the DC voltage received from the power source into an AC voltage signal; 1. A processor, comprising: a phase shift of each AC voltage signal converted by the switch-mode amplifier; the amplitude of each AC voltage signal converted by the switch-mode amplifier; a processor configured to control 1. A power generator comprising: (2) A power generator as described in embodiment 1, wherein each AC voltage signal is provided at the same frequency. (3) A power generator as described in embodiment 1, wherein the processor is configured to provide each AC voltage signal to one of multiple ablation electrodes of a medical tool. (4) A power generator as described in embodiment 3, wherein the amplitude of each AC voltage signal corresponds to the power obtained by each ablation electrode. (5) A power generator as described in embodiment 1, wherein no intermodulation distortion (IMD) exists between the AC voltage signals.

[0055] (6) The power generator of embodiment 1, wherein each of the plurality of switch-mode amplifiers includes an N-channel metal-oxide-semiconductor field-effect (MOSFET) transistor. (7) The power generator of embodiment 1, wherein the processor is configured to control the MOSFET transistor to switch between different states to convert the DC voltage into amplitude pulses. (8) A system used to perform a medical ablation procedure, comprising: a medical tool including a plurality of electrodes used to apply radio frequency (RF) energy to ablate tissue; 1. A power generator comprising a power supply configured to generate a DC voltage, a phase shifter configured to shift a signal transmission phase angle; a plurality of switch-mode amplifiers each electrically connected to a corresponding one of the electrodes and each configured to convert the DC voltage received from the power source into an AC voltage signal provided to the corresponding electrode; a processor for calculating the power obtained by each electrode by: Controlling a phase shift of each AC voltage signal converted by the switch-mode amplifier; Controlling the amplitude of each AC voltage signal converted by the switch-mode amplifier; a processor configured to control the a power generator comprising: A system comprising: (9) The system of embodiment 8, wherein each AC voltage signal is provided at the same frequency. (10) The system described in embodiment 8, wherein the plurality of ablation electrodes are part of a medical tool.

[0056] (11) The system of embodiment 10, wherein the medical tool is a catheter. (12) The system of embodiment 10, wherein the amplitude of each AC voltage signal corresponds to the power obtained by each electrode. (13) The system of embodiment 8, wherein no intermodulation distortion (IMD) exists between the AC voltage signals. (14) The system of embodiment 8, wherein each of the plurality of switch-mode amplifiers includes an N-channel metal-oxide-semiconductor field-effect (MOSFET) transistor. (15) The system of embodiment 8, wherein the processor is configured to control the MOSFET transistor to switch between different states to convert the DC voltage into amplitude pulses.

[0057] (16) A method of controlling power delivered for a medical ablation procedure, comprising: providing a DC voltage; converting the DC voltage into a corresponding AC voltage signal by each of a plurality of switch mode amplifiers; Controlling a phase shift of each AC voltage signal converted by the switch-mode amplifier; Controlling the amplitude of each AC voltage signal converted by the switch-mode amplifier; A method comprising: (17) The method of embodiment 16, wherein each AC voltage signal is provided at the same frequency. (18) The method of embodiment 16, further comprising providing each AC voltage signal to one of a plurality of ablation electrodes of a medical tool. (19) The method of embodiment 16, wherein the amplitude of each AC voltage signal corresponds to the power delivered by each ablation electrode. (20) The method of embodiment 16, wherein no intermodulation distortion (IMD) is present between the AC voltage signals.

Claims

1. 1. A power generator for use with a medical tool used to perform a medical ablation procedure, comprising: a power supply configured to generate a DC voltage; a phase shifter configured to shift a signal transmission phase angle; a plurality of switch mode amplifiers each configured to convert the DC voltage received from the power source into an AC voltage signal; 1. A processor, comprising: a phase shift by the phase shifter of each AC voltage signal converted by the switch-mode amplifier; the amplitude of each AC voltage signal converted by the switch-mode amplifier; and a processor configured to control the power supply to each of the electrodes by controlling 1. A power generator comprising:

2. 10. The power generator of claim 1, wherein each AC voltage signal is provided at the same frequency.

3. The power generator of claim 1 , wherein the processor is configured to provide each AC voltage signal to one of a plurality of ablation electrodes of a medical tool.

4. 4. The power generator of claim 3, wherein the amplitude of each AC voltage signal corresponds to the power delivered by each ablation electrode.

5. 10. The power generator of claim 1, wherein power is controlled using a single frequency such that no intermodulation distortion (IMD) exists between the AC voltage signals.

6. 10. The power generator of claim 1, wherein each of the plurality of switch-mode amplifiers includes an N-channel metal-oxide-semiconductor field-effect (MOSFET) transistor.

7. 7. The power generator of claim 6, wherein the processor is configured to control the MOSFET transistors to switch between different states to convert the DC voltage into amplitude pulses.

8. 1. A system for use in performing a medical ablation procedure, comprising: a medical tool including a plurality of electrodes used to apply radio frequency (RF) energy to ablate tissue; 1. A power generator comprising a power supply configured to generate a DC voltage, a phase shifter configured to shift a signal transmission phase angle; a plurality of switch-mode amplifiers each electrically connected to a corresponding one of the electrodes and each configured to convert the DC voltage received from the power source into an AC voltage signal provided to the corresponding electrode; a processor for controlling the power supply to each electrode; controlling a phase shift by the phase shifter of each AC voltage signal converted by the switch-mode amplifier; Controlling the amplitude of each AC voltage signal converted by the switch-mode amplifier; a processor configured to control the a power generator comprising: A system comprising:

9. 9. The system of claim 8, wherein each AC voltage signal is provided at the same frequency.

10. The system of claim 8 , wherein the plurality of ablation electrodes are part of a medical tool.

11. The system of claim 10 , wherein the medical tool is a catheter.

12. The system of claim 10 , wherein the amplitude of each AC voltage signal corresponds to the power available from each electrode.

13. 9. The system of claim 8, wherein power is controlled using a single frequency so that no intermodulation distortion (IMD) exists between the AC voltage signals.

14. 9. The system of claim 8, wherein each of the plurality of switch-mode amplifiers comprises an N-channel metal-oxide-semiconductor field-effect (MOSFET) transistor.

15. 15. The system of claim 14, wherein the processor is configured to control the MOSFET transistor to switch between different states to convert the DC voltage into amplitude pulses.

16. 1. A method of operating a power generator for supplying power to a medical tool for a medical ablation procedure, the power generator comprising a plurality of switch mode amplifiers and a processor, the method comprising: the processor: converting a DC voltage into a corresponding AC voltage signal by each of the plurality of switch mode amplifiers; Controlling a phase shift of each AC voltage signal converted by the switch-mode amplifier; Controlling the amplitude of each AC voltage signal converted by the switch-mode amplifier; and controlling the power supply to each of the electrodes by

17. 17. The method of claim 16, wherein each AC voltage signal is provided at the same frequency.

18. The method of claim 16, further comprising the processor providing each AC voltage signal to one of a plurality of ablation electrodes of a medical tool.

19. 17. The method of claim 16, wherein the amplitude of each AC voltage signal corresponds to the power delivered by each ablation electrode.

20. 17. The method of claim 16, wherein power is controlled using a single frequency so that no intermodulation distortion (IMD) is present between the AC voltage signals.

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