CN218165361U - Pulsed electric field ablation apparatus - Google Patents
Pulsed electric field ablation apparatus Download PDFInfo
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- CN218165361U CN218165361U CN202221757115.1U CN202221757115U CN218165361U CN 218165361 U CN218165361 U CN 218165361U CN 202221757115 U CN202221757115 U CN 202221757115U CN 218165361 U CN218165361 U CN 218165361U
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Abstract
The utility model provides a pulsed electric field melts equipment, it includes pulse generating circuit, current sensor and short-circuit protection module, pulse generating circuit includes a DC power supply, relay and constitutes two half-bridge circuit of full-bridge structure, two half-bridge circuit's positive polarity input side passes through the relay with DC power supply's positive voltage output links to each other and negative polarity input side links to each other with ground, two half-bridge circuit's output connection load, current sensor is used for detecting DC power supply's output current to feed back corresponding voltage, short-circuit protection module connects pulse generating circuit with current sensor, short-circuit protection module is used for judging whether the voltage of current sensor output exceeds a reference voltage, if, then breaks off the relay to can effectively avoid overflowing the influence to melting the object, improve pulsed electric field and melt equipment's security.
Description
Technical Field
The utility model relates to the field of medical equipment, especially, relate to a pulsed electric field melts equipment.
Background
A normal sinus rhythm of the heart begins at the sinoatrial node, which generates a depolarization wave causing depolarization of the myocardial tissue cells, depolarization of adjacent myocardial tissue cells, and transatrial propagation of depolarization to contract the atrium and empty blood from the atrium into the ventricle, which is then delivered to the myocardial tissue cells of the ventricle via the atrioventricular node and the his bundle. Depolarization of the cells propagates across the ventricles, causing them to contract. The conduction system implements an organized myocardial contraction sequence, resulting in a regular heartbeat.
The uneven distribution of the refractoriness of the cardiomyocytes in certain parts of the heart may lead to abnormal conduction paths in the heart tissue, possibly resulting in wavelets of the cardiac electrical signal circulating around certain tissues. Abnormal conduction pathways cause abnormal, irregular and possibly fatal cardiac arrhythmias. Arrhythmias may occur in the atria, such as in the form of atrial tachycardia, atrial fibrillation or atrial flutter. Arrhythmias may also occur in the ventricles, such as in the form of ventricular tachycardia.
A method of treating cardiac arrhythmias includes creating one or more lesions in myocardial tissue that divide independent linear lesions in the myocardium such that aberrant conduction pathways cannot be formed. The method for manufacturing the above-mentioned lesion may be to apply radio frequency energy to myocardial cells of the target site or to perform cryogenic cooling, etc., but has a potential disadvantage in that non-target tissues such as the esophagus or the phrenic nerve may be damaged at the same time.
Pulsed Field Ablation (PFA) is an ablation method in which a plurality of short-duration, high-voltage electric pulses are used to release ablation energy by designing an appropriate pulsed electric field, so that irreversible electroporation (IRE) is formed in a cell membrane, thereby causing a change in permeability of the cell membrane, disrupting homeostasis of the cell, and finally causing apoptosis. Pulsed electric field ablation has attracted attention in recent years for its applications in cardiac ablation, particularly atrial fibrillation, due to its advantages such as non-thermal ablation, tissue specificity, etc.
Research shows that when pulsed electric field ablation is performed, a large current is sometimes generated between two electrodes arranged on an ablation tissue, namely, an overcurrent phenomenon, and the excessive current passing through the ablation tissue may have adverse effects on the ablation tissue, so that the excessive current passing through the ablation tissue for a long time should be avoided as much as possible, and in order to solve the overcurrent problem, the current pulsed electric field ablation apparatus needs to be improved.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problems, the present invention provides a pulsed electric field ablation apparatus.
The utility model provides a pulsed electric field melts equipment includes:
the pulse generation module comprises a direct-current power supply, a relay and two half-bridge circuits forming a full-bridge structure, wherein positive polarity input sides of the two half-bridge circuits are connected with a positive voltage output end of the direct-current power supply through the relay, negative polarity input sides of the two half-bridge circuits are connected with the ground, and output ends of the two half-bridge circuits are connected with a load;
the current sensor is used for detecting the output current of the direct current power supply and feeding back corresponding voltage;
and the short-circuit protection module is connected with the pulse generation module and the current sensor and is used for judging whether the voltage output by the current sensor exceeds a reference voltage or not, and if so, the relay is disconnected.
Optionally, the current sensor is a hall sensor.
Optionally, each of the half-bridge circuits includes:
an upper switch connected to a positive voltage output terminal of the DC power supply; and
a lower switch connected to ground, the upper switch and the lower switch forming a push-pull output structure.
Optionally, the pulse generating circuit further includes:
the first current limiting resistor is connected between the relay and the upper switches of the two half-bridge circuits, and the second current limiting resistor is connected between the lower switches of the two half-bridge circuits and the ground.
Optionally, the pulse generating circuit further includes:
and the energy storage capacitor and the discharge resistor are respectively connected between the serial node of the relay and the first current limiting resistor and the ground.
Optionally, each of the half-bridge circuits includes a first parallel structure disposed between the dc power supply and the upper switch, the first parallel structure includes a plurality of first adjusting resistors connected in parallel and switches disposed on at least some of the parallel branches, and a total resistance of the first parallel structure is the first current limiting resistor.
Optionally, each half-bridge circuit includes a second parallel structure disposed between the lower switch and ground, the second parallel structure includes a plurality of second adjusting resistors connected in parallel and switches disposed on at least some of the parallel branches, and the total resistance of the second parallel structure is the second current limiting resistor.
Optionally, the short-circuit protection module includes:
a first comparator, a positive input end of which is connected with the voltage fed back by the current sensor, a negative input end of which is connected with the reference voltage, and when the feedback voltage is greater than the reference voltage, the first comparator outputs a high level;
a negative input end of the second comparator is connected with the output end of the first comparator, a positive input end of the second comparator is connected with a constant voltage, and when the first comparator outputs a high level, the second comparator outputs a low level;
a base electrode and a collector electrode of the triode Q4 are connected with the output end of the second comparator, an emitting electrode of the triode Q4 is grounded, and when the second comparator outputs low level, the triode Q4 is disconnected;
the anode of the thyristor Q2 is connected with a first power supply voltage, the cathode of the thyristor Q2 is grounded, the gate of the thyristor Q2 is connected with the collector of the triode Q4, and when the triode Q4 is disconnected, the thyristor Q2 is switched on;
the input end of the optocoupler OC1 is connected with the thyristor Q2, when the thyristor Q2 is conducted, the optocoupler OC1 is conducted, and a current protection signal node connected with the output end of the optocoupler OC1 is at a high level;
a base electrode of the triode Q1 is connected with the current protection signal node, and when the current protection signal node is at a high level, the triode Q1 is conducted;
first relay JK1, the input is connected triode Q1, and the output is connected the relay works as triode Q1 switches on, first relay JK1 circular telegram actuation, the input of relay is the suspension state, the relay disconnection.
Optionally, the short-circuit protection module includes:
a base electrode of the triode Q5 is connected with the current protection signal node, and when the current protection signal node is at a high level, the triode Q5 is conducted;
the input end of the second relay JK2 is connected with the triode Q5, the output end of the second relay JK2 is connected with the direct current power supply, when the triode Q5 is conducted, the second relay JK2 is electrified and attracted, the input end of the direct current power supply is in a suspension state, and the output of the direct current power supply is disconnected.
Optionally, the short-circuit protection module includes:
and a collector of the triode Q3 is connected with the anode of the thyristor Q2, an emitter is grounded, a base is connected with a reset signal, when the reset signal is high level, the triode Q3 is switched on, the thyristor Q2 is switched off, a current protection signal node is low level, a pin of the first relay JK1 is connected with the input end of the relay, and the relay is closed.
The utility model provides a pulsed electric field melts equipment includes impulse generation circuit, current sensor and short-circuit protection module, current sensor is used for detecting DC power supply's output current among the impulse generation circuit to feedback corresponding voltage, short-circuit protection module connects impulse generation circuit with current sensor, short-circuit protection module is used for judging whether the voltage of current sensor output exceeds a reference voltage, if, then breaks off the relay to can effectively avoid overflowing to melting the influence of object, improve pulsed electric field and melt the security of equipment.
Drawings
Fig. 1 is a block diagram of a pulsed electric field ablation device according to an embodiment of the present invention.
Fig. 2 is a circuit diagram of a pulse generator according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of a push-pull output structure employed by the pulse generating circuit shown in fig. 2.
Fig. 4 is a schematic diagram of a pulse train output by the pulse generator according to an embodiment of the present invention.
Fig. 5 is a circuit diagram of a positive charging of a capacitive load using the pulse generating circuit shown in fig. 2.
Fig. 6 is a circuit diagram of a case where the pulse generating circuit shown in fig. 2 is used to reversely charge the capacitive load.
Fig. 7 is a circuit diagram of a pulse generator in a pulse generator according to another embodiment of the present invention.
Fig. 8 is a schematic diagram of the trigger pulse signal, the edge count, the pulse output control signal, and the channel control signal in the pulsed electric field ablation device according to an embodiment of the present invention.
Fig. 9 is a circuit diagram of a short circuit protection module in a pulsed electric field ablation device in accordance with an embodiment of the present invention.
Detailed Description
The pulsed electric field ablation device of the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are in simplified form and are not to precise scale, and are provided for convenience and clarity in describing the embodiments of the present invention. The terms "first" and "second," and the like, hereinafter are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances.
Referring to fig. 1, embodiments of the present invention relate to a pulsed electric field ablation device 100 by which a pulse train of a certain frequency and a certain energy can be delivered to cardiac tissue, such as cardiac tissue of a patient with atrial fibrillation. Illustratively, the pulse train includes 20 and more pulse trains, such as 30-150 pulse trains, which may have an inter-phase delay of 0-200 μ s and a pulse width of from nanoseconds to microseconds, illustratively 0.5-150 μ s. The pulse train is relatively safe, effective, flexible and adjustable. In some embodiments, the pulsed electric field ablation device 100 can also include a plurality of ECG electrodes that are placed on the patient's body during the ablation procedure, through which the patient's cardiac activity is detected, and burst delivery can be performed during specific portions of the cardiac cycle, such as during the ventricular refractory period.
The disclosed cardiac pulse ablation system 100 includes a pulse generator 110 and a delivery device 120, where the delivery device 120 may be coupled directly to the pulse generator 110, or coupled to the pulse generator 110 through other intermediate devices. The delivery device 120 may include an elongated body, such as a catheter or sheath. The body has a proximal end and a distal end and may have one or more lumens therethrough inside to enable electrical and/or fluid communication between the proximal and distal ends. The distal end of the body may also have an energy delivery element, such as an electrode, which may be one or more and configured as two poles, cathode and anode, opposite, to deliver energy to the cardiac tissue. The pulse generator 110 includes a pulse generating device, an energy control, and communication therebetween.
The pulse generator 110 includes a pulse generator 111 and an energy control module 112, and may further include a processing module 113, an input and output module 114, and a short-circuit protection module 115, which will be described in detail below.
The pulse generating means 111 comprises a pulse generating circuit. Referring to fig. 2, in some embodiments, the pulse generating circuit includes a DC power source DC and two half-bridge circuits forming a full-bridge structure, wherein a positive polarity input side of each of the two half-bridge circuits is connected to a positive voltage output terminal of the DC power source DC, a negative polarity input side of each of the two half-bridge circuits is connected to ground, and an output terminal of each of the two half-bridge circuits is connected to a load Cx. The load Cx is here a capacitive load. The pulsed electric field ablation device 100 of the present embodiment is used to perform pulsed electric field ablation, whereby the target tissue at the load Cx to which energy is delivered by the electrodes of the delivery device 120, such as endocardial tissue of the circum-pulmonary vein of an atrial fibrillation patient.
The utility model discloses among the pulse generating circuit of pulse generating device 111 of embodiment, two half-bridge circuits that are located load Cx both sides constitute the full-bridge structure. The switches S of each half-bridge circuit include an upper switch connected to the positive voltage output of the DC power supply DC and a lower switch connected to ground. The upper switch and the lower switch can be implemented by using a solid-state switch module, and more specifically, a high-voltage solid-state switch module, for example, with an operating voltage (peak-to-peak value) of about 500V to 8kV. Each of the solid state switching modules may include a plurality of power field effect transistors connected in series. In this embodiment, the DC power supply DC is a high voltage DC power supply, and the output voltage thereof can be as high as 2kV.
Referring to fig. 3, the upper and lower switches in each of the half-bridge circuits, for example, constitute a push-pull output structure as shown in fig. 3, in which the upper and lower switches use the same control terminal (V) IN ) Controlling the upper and lower switches to be alternately turned on when the control terminal is switched between a high level and a low level, so that the output terminal (V) OUT ) Is the input terminal voltage (V) VDD ) Or ground (0V). Referring to fig. 2, the left half-bridge circuit includes an upper switch S1 and a lower switch S2 arranged in a push-pull output configuration, and the right half-bridge circuit includes an upper switch S3 and a lower switch S4 arranged in a push-pull output configuration. Because a push-pull output structure is adopted, when the full-bridge structure works, the upper switch S1 and the lower switch S2 are always kept to be oneIn the off state and the other on state, the upper switch S3 and the lower switch S4 always keep one off and the other on state. By using the push-pull output structure, the high level and the low level applied to the load Cx can have driving capability under the condition of not increasing the circuit complexity, and the ablation effectiveness is enhanced. The switches S of the two half-bridge circuits are both in a push-pull output structure, namely double push-pull output is formed, an external trigger pulse signal drives an upper switch or a lower switch in each push-pull output structure to be repeatedly switched on and off, and input direct-current voltage is chopped, so that bipolar pulses can be output.
Fig. 4 is a schematic diagram of a pulse train output by the pulse generator according to an embodiment of the present invention. In fig. 4, CH1 represents the trigger pulse signal received by the push-pull output structure of the left half-bridge in fig. 2, CH2 represents the trigger pulse signal received by the push-pull output structure of the right half-bridge in fig. 2, CH1 and CH2 have a certain phase difference (e.g., 0 μ s to 200 μ s), and what is actually applied to the load Cx is a bipolar pulse train, as shown by "output waveform" in fig. 4.
Fig. 5 is a circuit diagram of the pulse generating circuit shown in fig. 2 for positively charging the capacitive load. For simplicity, the relay KA1, the energy storage capacitor C1 and the discharge resistor R1 in fig. 2 are omitted in fig. 5. Referring to fig. 4 and 5, when CH1 is high and CH2 is low, the upper switch S1 of the left half-bridge in fig. 2 is turned on, the lower switch S2 is turned off, the upper switch S3 of the right half-bridge in fig. 2 is turned off, and the lower switch S4 is turned on, and the charging direction is as shown by the arrow in fig. 5. At this time, the load Cx is positively charged, and the polarity of the voltage across the load Cx after the positive charging is completed appears positive left and negative right, i.e., positive polarity.
Fig. 6 is a circuit diagram of a case where the pulse generating circuit shown in fig. 2 is used to reversely charge the capacitive load. For simplicity, the relay KA1, the energy storage capacitor C1 and the discharge resistor R1 in fig. 2 are omitted in fig. 6. Referring to fig. 4 and 6, when CH1 is low and CH2 is high, the upper switch S1 of the left half-bridge in fig. 2 is turned off, the lower switch S2 is turned on, the upper switch S3 of the right half-bridge is turned on, and the lower switch S4 is turned off, and the charging direction is as shown by the arrow in fig. 6. At this time, the load Cx is reversely charged, and the polarity of the voltage across the load Cx after the reverse charging is completed appears negative left and positive right, i.e., negative polarity.
It can be seen that the polarity of the voltage developed on the specimen Cx by the trigger pulse signal CH1 is opposite to the polarity of the voltage developed on the load Cx by the trigger pulse signal CH 2. By alternately performing the above-described forward charging process and reverse charging process for the load Cx and repeating these processes a plurality of times, the pulse train actually applied to the load Cx is a bipolar pulse train. The purpose of generating a bipolar pulse is to apply a positive pulse and a negative pulse alternately to a load Cx, and when the electrical stimulation of the positive pulse to a cell does not stimulate nerve fibers yet and generates an action potential having an influence, the action potential of a cell membrane is lowered by the negative pulse, thereby preventing muscle contraction. By repeating the above steps, the action potential can be always kept below the threshold potential for generating muscle contraction, thereby solving the problem of muscle contraction in the operation process and improving the effectiveness and safety of pulse ablation.
Referring to fig. 2, the pulse generating circuit can include relay KA1, first current-limiting resistor R2, second current-limiting resistor R3, energy-storage capacitor C1 and discharge resistor R1, and relay KA1 sets up in direct current power supply DC and two between the half-bridge circuit, first current-limiting resistor R2 is connected between relay KA1 and two half-bridge circuit's last switch, and second current-limiting resistor R3 is connected between two half-bridge circuit's lower switch and ground, and energy-storage capacitor C1 connects between relay KA1 and first current-limiting resistor R2's series node and ground, and discharge resistor R1 connects between relay KA1 and first current-limiting resistor R2's series node and ground. In this embodiment, the DC power supply DC, the relay KA1, the first current limiting resistor R2, the second current limiting resistor R3, the energy storage capacitor C1, and the discharging resistor R1 are a set of devices, and are shared by two half-bridge circuits.
The relay KA1 is used for controlling the on-off of the DC power supply DC input, after the relay KA1 is closed, the DC voltage output by the DC power supply DC is input into the two half-bridge circuits, after the relay KA1 is opened, the output of the DC power supply DC is cut off, for example, when the short circuit of the load Cx is detected, the relay KA1 can be opened, so that the electrical safety of the pulsed electric field ablation device 100 and the biological safety of an ablation object are protected. The energy storage capacitor C1 is used for storing electric energy and stabilizing the output voltage of the direct current power supply DC. The discharging resistor R1 is used for releasing the electric energy stored in the energy storage capacitor C1 through a loop formed by the energy storage capacitor C1 and the discharging resistor R1 when the relay KA1 is disconnected. The first current limiting resistor R2 and the second current limiting resistor R3 function as follows: on one hand, the load Cx is a capacitive load, the process of changing the voltage polarity of the load Cx is equivalent to rapid charging and discharging of the capacitive load, and the arrangement of the first current limiting resistor R2 and the second current limiting resistor R3 can adjust the current peak value in the charging and discharging processes of the load Cx, so that the current peak value can be ensured to be smaller than the maximum conduction peak value current which can be borne by the upper switch and the lower switch, and the upper switch and the lower switch are protected from being damaged by overcurrent; on the other hand, during the ablation process, the energy is delivered to the target tissue, i.e. the target tissue may be affected, the values of the time constant RC of the charging and discharging process can be adjusted by changing the resistance values of the first current limiting resistor R2 and the second current limiting resistor R3, so as to adjust the duration of the rising edge and the falling edge of the output pulse, and the duration of the rising edge and the falling edge of the pulse is controlled so that the duration of the pulse power reaching the high level is short enough to reduce the effect of the energy on the target tissue during the pulse generation, and the duration is expected to be in the order of nanoseconds, such as not higher than 200ns.
In the embodiment of the present invention, the first current limiting resistor R2 and the second current limiting resistor R3 connected in series with the unilateral bridge arm can adopt a multi-path resistor, and switch on by selecting a part or all of the multi-path resistors, and adjust the resistance of the current limiting resistor connected in series with the unilateral bridge arm, and then adjust the rise time and fall time of the bipolar pulse edge applied to the load Cx. Fig. 7 is a circuit diagram of a pulse generator according to another embodiment of the present invention. The main difference between fig. 7 and the pulse generating circuit shown in fig. 2 is that the first current limiting resistor R2 and the second current limiting resistor R3 are connected in parallel. Therefore, the parallel structure will be mainly described below.
Referring to fig. 7, alternatively, in each of the half-bridge circuits, a direct current power source DC and two of the half-bridgesThe upper switches of the circuit are provided with a first parallel structure which comprises a plurality of first adjusting resistors (R in figure 7) connected in parallel lim1 ，R lim2 ，R lim3 ，R lim4 ，R lim5 ) And a switch arranged on at least part of the parallel branches, the first parallel structure can be shared by the two half-bridge circuits, and the total resistance of the first parallel structure is a first current limiting resistor R2. In the first parallel structure, the resistance values of the first adjusting resistors may be the same, not completely the same, or different from each other. By controlling the switches in the respective parallel branches to be on or off (each switch being controllable by the processing module 113), the total resistance of the first parallel structure can be adjusted, i.e. the resistance of the first current limiting resistor R2 is changed. Specifically, when the first current limiting resistor R2 is increased, the rise time of the bipolar pulse edge applied to the load Cx is increased, and when the first current limiting resistor R2 is decreased, the rise time of the bipolar pulse edge applied to the load Cx is decreased.
Referring to fig. 7, optionally, in each of the half-bridge circuits, a second parallel structure may be disposed between the lower switch and the ground, and the second parallel structure includes a plurality of second regulating resistors (e.g., R in fig. 7) connected in parallel lim6 ，R lim7 ，R lim8 ，R lim9 ，R lim10 ) And a switch disposed on at least a portion of the parallel branches. This second parallel configuration may be shared by the two half-bridge circuits, the total resistance of which is a second current limiting resistor R3. In the second parallel structure, the resistance values of the second adjusting resistors may be the same, not completely the same, or different from each other. By controlling the on/off of the switches in each parallel branch (each switch may be controlled by the processing module 113), the total resistance of the second parallel structure may be adjusted, i.e., the resistance of the second current limiting resistor R3 may be changed. Specifically, when the second current limiting resistor R3 is increased, the fall time of the bipolar pulse edge applied to the load Cx is increased, and when the second current limiting resistor R3 is decreased, the fall time of the bipolar pulse edge applied to the load Cx is decreased.
The parameters of the bipolar pulse train applied to the load Cx can be adjusted by adjusting the trigger pulse signals of the two aforementioned push-pull output structures, for example, the on/off times of the upper switch and the lower switch of the corresponding two half-bridge circuits in fig. 2 can be changed by controlling the trigger pulse signal CH1 and/or the trigger pulse signal CH2 shown in fig. 4, so as to control the parameters such as the frequency and the duty ratio of the bipolar pulse train.
Referring to fig. 1, in the present embodiment, the energy control module 112 is used to provide trigger pulse signals to two half-bridge circuits in the pulse generator 111. The energy control module 112 includes, for example, an FPGA chip. The FPGA (Field Programmable gate array) has good stability and low delay, so that the working speed can be fast, the FPGA utilizes the advantage of hardware parallelism, breaks through a sequential execution mode, completes more processing tasks in each clock period, surpasses the operational capability of a Digital Signal Processor (DSP), and is favorable for improving the effectiveness of pulsed electric Field ablation.
Specifically, the energy control module 112 includes a pulse sequence generation program 112a implemented by using FPGA resources, and pulses generated by the pulse sequence generation program 112a are used for forming trigger pulse signals of the two half-bridge circuits. The pulse sequence generating program 112a can be written in a hardware description language (such as Verilog HDL) and downloaded into the circuitry of the FPGA, so as to implement the pulse sequence generating program 112a using FPGA resources.
Fig. 8 is a schematic diagram of a trigger pulse signal, an edge count, a pulse output control signal, and a channel control signal in the pulsed electric field ablation apparatus according to an embodiment of the present invention. Referring to fig. 8, under a set start signal (e.g., a power-on signal of the energy control module 112), a pulse sequence generation routine 112a is executed to generate an electrical pulse (as indicated by "repetitive pulses" in fig. 8) at a set period. By way of example, the pulse width of the electrical pulse generated by the pulse sequence generation program 112a is 0.5 μ s to 150 μ s, and a preferred range may be 50 μ s to 150 μ s, and more specifically, for example, 100 μ s, the interval between two adjacent electrical pulses is 100 μ s to 300 μ s, and more specifically, for example, 200 μ s, and the electrical pulse generation period of the pulse sequence generation program 112a is 150 μ s to 450 μ s, and more specifically, for example, 300 μ s.
In this embodiment, the upper switch and the lower switch of each half-bridge circuit are push-pull output structures, and each push-pull output structure is triggered by one trigger pulse signal, and a dual push-pull output structure formed by two half-bridge circuits needs two trigger pulse signals (such as CH1 and CH2 described above). Accordingly, the energy control module 112 may include a first output channel (shown as channel (1) in fig. 8) and a second output channel (shown as channel (2) in fig. 8), which correspond to the two push-pull output structures, respectively, and the electric pulses generated by the pulse sequence generating program 112a are provided to the two push-pull output structures through the first output channel and the second output channel, respectively.
The power control module 112 may further include a channel control signal 112b (shown as "channel enable/disable" in fig. 8) formed by using FPGA resources to control the first output channel and the second output channel to be turned on in turn, so as to control the trigger pulse signals sent to the two push-pull output structures. Referring to fig. 8, the channel control signal 112b is, for example, a square wave signal, when the channel control signal 112b is in an enable state (e.g., high level), the first output channel outputs the electrical pulses generated by the pulse sequence generation program 112a, and the second output channel is disabled, when one of the push-pull output structures (e.g., the push-pull output structure formed by the upper switch S1 and the lower switch S2 in fig. 2) of the pulse generation device 111 receives the trigger pulse signal, when the channel control signal 112b is in a disable state (e.g., low level), the second output channel outputs the electrical pulses generated by the pulse sequence generation program 112a, and the first output channel is disabled, when the other push-pull output structure (e.g., the push-pull output structure formed by the upper switch S3 and the lower switch S4 in fig. 2) of the pulse generation device 111 receives the trigger pulse signal.
The half period of the channel control signal 112b may be an integer multiple (where the integer multiple is at least 1) of the period of the electrical pulses generated by the pulse train generation program 112a, i.e., the channel control signal 112b may allow an integer number of electrical pulses to be sent to both push-pull output structures during the high level period and the low level period of the same period, respectively. Further, the channel control signal 112b may allow the same number of electrical pulses to be transmitted to both of the push-pull output structures during the high level period and the low level period of the same cycle, respectively. As an example, the period of the channel control signal 112b is, for example, 600 μ s, wherein the high level and the low level are both 300 μ s, and the period of the electric pulse generated by the above-mentioned pulse sequence generation program 112a is, for example, 300 μ s, that is, the channel control signal 112b sends one electric pulse to both of the push-pull output structures during the high level period and the low level period of the same period, respectively.
Since only one switch is on at the same time in each push-pull output structure, in this embodiment, a trigger pulse signal is alternately output to the two push-pull output structures by using the channel control signal 112b, so that bipolar pulses can be formed across the ablation load.
When the energy control module 112 transmits the trigger pulse signal to the pulse generator 111, the energy control module 112 may periodically transmit the electric pulse to the pulse generator 111 as a trigger pulse signal of two push-pull output structures as needed, and may transmit a plurality of electric pulses to the pulse generator 111 to form a pulse train for each period. To control the output of the electrical pulses every cycle, a pulse output control signal may be set within the energy control module 112 to enable or disable the output of the electrical pulses.
Specifically, referring to fig. 1, the energy control module 112 may include a pulse counting unit 112c and a pulse output control unit 112d; wherein the pulse counting unit 112c counts the electric pulses generated by the pulse train generation program 112a by detecting the rising edges of the electric pulses; the pulse output control unit 112d determines whether the number of the electric pulses is less than or equal to a first set value according to the counting result of the pulse counting unit 112 c; if yes, the pulse output control signal output by the pulse output control unit 112d is in an enable state (i.e., a pulse output enable signal), and at this time, the electrical pulse generated by the pulse sequence generation program 112a is sent to the corresponding push-pull output structure through the first output channel or the second output channel; if not, the pulse output control signal output by the pulse output control unit 112d is in a disable state (i.e. the pulse output disable signal), and at this time, the electrical pulse generated by the pulse sequence generation program 112a does not output the trigger pulse signal to any of the push-pull output structures. The first setting value here represents the maximum number of electrical pulses that can be output by the energy control module 112 in a single trigger pulse signal output period. In addition, the pulse output control unit 112d controls the start of the next trigger pulse signal output period, specifically, it may determine whether the pulse number is less than or equal to a second set value by reading the pulse number accumulated by the pulse counting unit 112c, if so, the pulse output control signal remains disabled, the electric pulse is not output to the pulse generating device 111, and if not, the pulse output control signal is switched to an enabled state to recover the output of the electric pulse, that is, the electric pulse generated by the pulse sequence generating program 112a is sent to the corresponding push-pull output structure through the first output channel or the second output channel, and the counting result of the pulse counting unit 112c is set to zero to count the electric pulse in a new period again.
In order to make the trigger pulse signal sent to the pulse generator 111 by the energy control module 112 conveniently adjust, so as to meet the requirements of different occasions, referring to fig. 1, the pulse generator 110 of the embodiment of the present invention further includes a processing module 113, the processing module 113 is connected with the energy control module 112, so as to adjust the parameter of the trigger pulse signal output by the energy control module 112. The processing module 113 includes, for example, a single chip microcomputer, and can modify the parameters of the pulse sequence generation program 112a through the setting of a software program, so that the flexibility is high, for example, the processing module 113 can adjust the parameters of the amplitude, the pulse width, the polarity, the duty cycle, the frequency, and the like of the electric pulses generated by the pulse sequence generation program 112a. The processing module 113 and the energy control module 112 may be configured by a System on Chip (SoC) architecture, and the two are connected through an SPI bus, for example, and the processing module 113 may also receive data fed back by the energy control module 112 through the SPI bus. In addition, the processing module 113 may be further connected to the pulse generating device 111, for example, may be connected to the DC power source DC in the pulse generating device 111 and the solid-state switches in the two half-bridge circuits, so as to control the output of the DC power source DC to be turned on and off and control the amplitude of the output voltage of the DC power source DC, and may also monitor whether the solid-state switches operate normally.
Referring to fig. 1, the pulse generator 110 of the present embodiment may further include an input and output module 114 to facilitate an operator to interact with the pulsed electric field ablation apparatus 100, where the input and output module 114 includes a terminal device, for example, an operator may read and adjust parameters of the pulsed electric field through the input and output module 114, or the input and output module 114 may be utilized to display environmental parameters at the load. For example, the operator may set parameters of the pulse train generation program 112a, the first and second setting values, and the like, by the input and output module 114, may set the output voltage amplitude of the DC power supply DC of the pulse generator 111, and may display the trigger pulse signal output by the energy control module 112 by a terminal device. After receiving the parameters set by the input and output module 114, the processing module 113 controls the energy control module 112 and the pulse generator 111 to operate according to the set parameters. In addition, the pulse generator 110 of the present embodiment may further include a power system, which converts an alternating current (e.g., 220V) into a direct current (e.g., 24V) and supplies power to other components in the pulse generator 110 through the input and output module 114.
It has been found that during pulsed electric field ablation, a large current, i.e., an overcurrent, is sometimes generated between two electrodes disposed on the ablated tissue, and the excessive current passing through the ablated tissue may adversely affect the ablated tissue, so that it is desirable to avoid the excessive current passing through the ablated tissue for a long time.
In order to reduce the effect of overcurrent on the ablated tissue, in the pulse generator 110 of the present embodiment, the pulse generating device 111 may further include a current sensor for detecting the output current of the DC power supply DC shown in fig. 2 or fig. 7 and outputting a corresponding voltage signal. The current sensor is for example a hall sensor. Referring to fig. 1, the pulse generator 110 may further include a short-circuit protection module 115, where the short-circuit protection module 115 is connected to the pulse generating device 111, and the short-circuit protection module 115 is configured to determine whether a voltage fed back by the current sensor exceeds a reference voltage, and if so, disconnect a relay KA1 (see fig. 2 or fig. 7) disposed at the DC output terminal of the DC power supply. By utilizing the current sensor and the short-circuit protection module 115, when an overcurrent phenomenon occurs, the relay KA1 is disconnected, so that the upper switch and the lower switch in the half-bridge circuit are disconnected, the overcurrent phenomenon cannot be sustained, and adverse effects on ablation tissues can be reduced. The magnitude of the reference voltage may be set by the processing module 113 or a potentiometer.
In this embodiment, the short-circuit protection module 115 may include a comparator and a hardware circuit connected to the comparator, when the voltage fed back by the current sensor exceeds the reference voltage, the hardware circuit controls the relay KA1 to be turned off, and the control response is faster through the hardware circuit, so that the influence of overcurrent on the ablated tissue can be better reduced. The hardware circuit may be disposed on a PCB board. Some elements in the hardware circuit are powered by a 5V power supply, and some elements are powered by a 24V power supply, so that a 24V and 5V conversion circuit is further provided in the circuit of the short-circuit protection module 115 shown in fig. 9.
Specifically, referring to fig. 9, the short-circuit protection module 115 includes the first comparator 10, the reference voltage Current _ Ref is input to the negative input terminal of the first comparator 10, and the voltage Current _ OUT fed back by the Current sensor is input to the positive input terminal of the first comparator 10. R1 is a pull-up resistor. Current _ Ref _ Res represents a threshold voltage set by the potentiometer RP1, and Current _ Ref _ DAC represents a threshold voltage set by a DAC built in the processing module 113. GND represents ground for a 5V power supply. The processing module 113 has an MCU output pin 50.
When the voltage Current _ OUT fed back by the Current sensor is greater than the reference voltage Current _ Ref (representing that the circuit of the pulse generating device 111 is in an overcurrent state), pin 7 of the first comparator 10 in fig. 9 outputs a high impedance state, the pin 7 is connected to the power supply voltage VCC _5VDC through the pull-up resistor, and the first comparator 10 outputs a high level. If the voltage Current _ OUT fed back by the Current sensor is greater than the reference voltage Current _ Ref (indicating that the circuit of the pulse generating device 111 is in a normal state), the first comparator 10 outputs a low level.
The base and collector of the transistor Q4 are connected to the output terminal of the second comparator 20, and the emitter is grounded, so that when the second comparator 20 outputs a low level (indicating that the circuit of the pulse generator 111 is in an overcurrent state), the transistor Q4 is turned off (disconnected). The positive pole of thyristor Q2 is connected to first mains voltage VCC, and the negative pole ground connection, and the gate pole is connected with triode Q4's collecting electrode, and when triode Q4 does not switch on, thyristor Q2's gate level is the high level, and thyristor Q2 switches on. If the second comparator 20 outputs a high level (indicating that the circuit of the pulse generator 111 is in a normal state), the transistor Q4 is turned on, and at this time, the gate of the thyristor Q2 is grounded, no current flows, and the thyristor Q2 is not turned on. If the thyristor Q2 is not turned on, the following circuit will not operate, the closed state of the relay KA1 in the pulse generating device 111 will not change, the voltage across the relay JK1 in fig. 9 is the power voltage VIN _24VDC, and the relay KA1 in fig. 2 or fig. 7 is in the closed state.
Thyristor Q2 is connected to opto-coupler OC 1's input, when thyristor Q2 switches on (representing that the circuit of pulse generation device 111 is in the overcurrent state), opto-coupler OC1 can switch on, current protection signal node Current _ ProtectCtlS is the high level, triode Q1's base is the high level promptly, triode Q1 switches on, pilot lamp LED2 is bright, can make relay JK1 (note first relay JK1 simultaneously, triode Q1 is connected to its input, relay KA1 in pulse generation device 111 is connected to the output), then relay JK1 switch actuation, on pin 5 can be hit to relay JK 1's pin 4, two port terminals 30 are the suspended state this moment, relay KA1 among the above-mentioned pulse generation device 111 is connected on two port terminals 30, therefore when two port terminals 30 are the suspended state, relay KA 1's in pulse generation device 111 input is the suspended state, relay KA1 breaks off.
The short-circuit protection module 115 may also control the output of the DC power supply DC to be disconnected through a hardware circuit. Referring to fig. 9, when the Current protection signal node Current _ ProtectCtlS is at a high level (representing that the circuit of the pulse generator 111 is in an overcurrent state), the transistor Q5 is turned on, the indicator light LED3 is turned on, the relay JK2 (denoted as a second relay JK2, an input end of the relay JK2 is connected to the transistor Q5, an output end of the relay JK2 is connected to the DC power supply DC in the pulse generator 111) is turned on and pulled, the two port terminal 40 connected to the relay JK2 is in a floating state, one input end of the DC power supply DC in the pulse generator 111 is connected to the two port terminal 40 connected to the relay JK2, and thus the output of the DC power supply DC is cut off.
The relay KA1 and the DC power supply DC can be reset by a reset signal. Referring to fig. 9, in this embodiment, the anode terminal of the thyristor Q2 is an overcurrent signal node Current _ ProtectState, when the thyristor Q2 is turned on, the overcurrent signal node Current _ ProtectState is at a low level, the indicator light LED1 is turned on, and the processing module 113 may obtain information of whether the circuit of the pulse generating device 111 is in an overcurrent state by reading a voltage of the overcurrent signal node Current _ ProtectState. When resetting is performed, the processing module 113 may provide a high level to the reset signal node Current _ Rst in fig. 9, so that the triode Q3 is turned on, after the triode Q3 is turned on, a voltage drop between an anode and a cathode of the thyristor Q2 is 0, and thus the thyristor Q2 is turned off, the Current protection signal node Current _ ProtectCtlS is a low level, at this time, the pin 4 of the relay JK1 hits the pin 5, the port voltage of the two port terminal 30 connected to the relay JK1 is 24V, and the relay KA1 connected to the two port terminal 30 is closed. When the output of the DC power supply DC needs to be reset, the reset signal of the pulse generating circuit can be used to reset the output.
In the pulsed electric field ablation device 100 of this embodiment, be provided with relay KA1 between pulse generation circuit's DC power supply and the full-bridge structure, relay KA1 can control the output of full-bridge structure, pulsed electric field ablation device 100 still includes current sensor and short-circuit protection module 115, current sensor is used for detecting DC power supply's output current to feed back corresponding voltage, short-circuit protection module 115 is through judging whether the voltage of current sensor feedback exceeds a reference voltage and judges whether pulse generation circuit overflows, if, then breaks off relay KA1 can effectively avoid overflowing the influence to melting the object, improves the security of pulsed electric field ablation device 100.
The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the claims, and any person skilled in the art can use the above-disclosed method and technical contents to make possible changes and modifications to the technical solution of the present invention without departing from the spirit and scope of the present invention, and therefore, any simple modifications, equivalent changes and modifications made to the above embodiments by the technical substance of the present invention all belong to the protection scope of the technical solution of the present invention.
Claims (10)
1. A pulsed electric field ablation device, comprising:
the pulse generating circuit comprises a direct current power supply, a relay and two half-bridge circuits forming a full-bridge structure, wherein positive polarity input sides of the two half-bridge circuits are connected with a positive voltage output end of the direct current power supply through the relay, negative polarity input sides of the two half-bridge circuits are connected with the ground, and output ends of the two half-bridge circuits are connected with a load;
the current sensor is used for detecting the output current of the direct current power supply and feeding back corresponding voltage;
and the short-circuit protection module is connected with the pulse generation circuit and the current sensor and is used for judging whether the voltage output by the current sensor exceeds a reference voltage or not, and if so, the relay is disconnected.
2. The pulsed electric field ablation device of claim 1 wherein the current sensor is a hall sensor.
3. The pulsed electric field ablation device of claim 1, wherein each of the half-bridge circuits comprises:
an upper switch connected to a positive voltage output terminal of the DC power supply; and
a lower switch connected to ground, the upper switch and the lower switch forming a push-pull output structure.
4. The pulsed electric field ablation device of claim 3, wherein the pulse generation circuit further comprises:
the first current limiting resistor is connected between the relay and the upper switches of the two half-bridge circuits, and the second current limiting resistor is connected between the lower switches of the two half-bridge circuits and the ground.
5. The pulsed electric field ablation device of claim 4 wherein the pulse generation circuit further comprises:
and the energy storage capacitor and the discharge resistor are respectively connected between the serial node of the relay and the first current limiting resistor and the ground.
6. The pulsed electric field ablation device of claim 4 wherein each of said half bridge circuits includes a first parallel configuration disposed between said relay and said upper switch, said first parallel configuration including a plurality of first conditioning resistors connected in parallel and switches disposed in at least some of the parallel branches, with the total resistance of said first parallel configuration being said first current limiting resistor.
7. The pulsed electric field ablation device of claim 4 wherein each of said half-bridge circuits includes a second parallel configuration disposed between said lower switch and ground, said second parallel configuration including a plurality of second regulating resistors connected in parallel and switches disposed in at least some of the parallel branches, with the total resistance of said second parallel configuration being said second current limiting resistor.
8. The pulsed electric field ablation device of claim 1, wherein the short-circuit protection module comprises:
a positive input end of the first comparator is connected with the voltage fed back by the current sensor, a negative input end of the first comparator is connected with the reference voltage, and when the voltage fed back by the current sensor is greater than the reference voltage, the first comparator outputs a high level;
a negative input end of the second comparator is connected with the output end of the first comparator, a positive input end of the second comparator is connected with a constant voltage, and when the first comparator outputs a high level, the second comparator outputs a low level;
a base electrode and a collector electrode of the triode Q4 are connected with the output end of the second comparator, an emitting electrode of the triode Q4 is grounded, and when the second comparator outputs low level, the triode Q4 is disconnected;
the anode of the thyristor Q2 is connected with a first power supply voltage, the cathode of the thyristor Q2 is grounded, the gate of the thyristor Q2 is connected with the collector of the triode Q4, and when the triode Q4 is disconnected, the thyristor Q2 is switched on;
the input end of the optocoupler OC1 is connected with the thyristor Q2, when the thyristor Q2 is conducted, the optocoupler OC1 is conducted, and a current protection signal node connected with the output end of the optocoupler OC1 is at a high level;
a base electrode of the triode Q1 is connected with the current protection signal node, and when the current protection signal node is at a high level, the triode Q1 is conducted;
first relay JK1, the input is connected triode Q1, and the output is connected the relay works as triode Q1 switches on, first relay JK1 circular telegram actuation, the input of relay is the suspended state, the relay disconnection.
9. The pulsed electric field ablation device of claim 8, wherein the short-circuit protection module comprises:
a base electrode of the triode Q5 is connected with the current protection signal node, and when the current protection signal node is at a high level, the triode Q5 is conducted;
the input end of the second relay JK2 is connected with the triode Q5, the output end of the second relay JK2 is connected with the direct current power supply, when the triode Q5 is conducted, the second relay JK2 is electrified and attracted, the input end of the direct current power supply is in a suspension state, and the output of the direct current power supply is disconnected.
10. The pulsed electric field ablation device of claim 8 wherein the short circuit protection module comprises:
and a collector of the triode Q3 is connected with an anode of the thyristor Q2, an emitter of the triode Q3 is grounded, a base of the triode Q3 is connected with a reset signal, when the reset signal is at a high level, the triode Q3 is switched on, the thyristor Q2 is switched off, a current protection signal node is at a low level, a pin of the first relay JK1 is connected with an input end of the relay, and the relay is closed.
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| CN116509534A (en) * | 2023-03-13 | 2023-08-01 | 浙江伽奈维医疗科技有限公司 | IGBT current detection and control device, system and method for steep pulse therapy |
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| CN116509534A (en) * | 2023-03-13 | 2023-08-01 | 浙江伽奈维医疗科技有限公司 | IGBT current detection and control device, system and method for steep pulse therapy |
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