CN112386328B - Cordless radio frequency ablation instrument - Google Patents

Abstract

The disclosure relates to the field of medical equipment, and discloses a cordless radio frequency ablation instrument. The cordless radiofrequency ablation instrument comprises: a radiofrequency ablation catheter; a handle sheath mechanically connected to the radiofrequency ablation catheter; the radio frequency ablation module is used for providing radio frequency current for the radio frequency ablation catheter; the handle sheath is including having the hollow structure that can open and shut the lid, and when the lid was opened, the radio frequency melts the module and can install in the handle sheath and with the radio frequency ablation catheter electricity coupling, when the lid was closed, the handle sheath inner space that the radio frequency melted the module place was isolated with handle sheath external seal for the aseptic environment of handle sheath inner space's aseptic environment outside can't be influenced.

Description

Cordless radio frequency ablation instrument

Technical Field

The present disclosure relates to the field of medical devices, and more particularly to cordless radiofrequency ablation techniques.

Background

When the vein is thermally ablated, the target vein vessel is heated by generating and releasing heat, so that the vein vessel is atrophied and closed. Currently, most radiofrequency ablation products adopt a reusable radiofrequency generator (usually a table type, using an alternating current power supply) and a disposable radiofrequency ablation catheter. The radio frequency generator is not generally sterilized, and the sterilized radio frequency ablation catheter is taken out during the operation and is connected to the radio frequency generator by a cable for operation.

The disadvantages of this design are:

1. the sterile product (radio frequency ablation catheter) and the bacteria product (radio frequency generator) are mixed, so that pollution is easily caused, and inflammation of a patient is caused;

2. during treatment, a doctor needs to pay attention to the radio frequency ablation catheter and the table radio frequency generator beyond a certain distance, and because the radio frequency generator with bacteria cannot be touched, another person needs to operate the radio frequency generator, so that inconvenience is brought, and misoperation is easy to occur;

3. the desk-top radio frequency generator is heavy and inconvenient to carry and circulate among different operating rooms.

Many physicians would therefore desire to be able to miniaturize the radiofrequency generator, such as a cordless radiofrequency ablation device that can be self-contained with a battery. However, if the rf generator containing the battery is integrated into the hand-held portion, the rf generator containing the battery needs to be sterilized, and the sterilization process may greatly affect the life of the active components such as the battery.

Disclosure of Invention

It is an object of the present disclosure to provide a cordless rf ablation instrument that meets the regulations for sterile surgery without requiring sterilization of active components such as batteries.

The application discloses, wireless radio frequency ablation apparatus includes:

a radiofrequency ablation catheter;

a handle sheath in mechanical communication with the radiofrequency ablation catheter;

the radiofrequency ablation module is used for providing radiofrequency current for the radiofrequency ablation catheter, comprises a battery and does not need sterilization before being used;

the handle sheath comprises a hollow structure with an openable cover, a sealing device is arranged between the cover and the handle sheath, when the cover is opened, the radio frequency ablation module can be installed in the handle sheath and electrically coupled with the radio frequency ablation catheter, and when the cover is closed, the inner space of the handle sheath where the radio frequency ablation module is located is sealed and isolated from the outer portion of the handle sheath, so that the sterile environment outside the handle sheath cannot be influenced by the sterile environment in the inner space of the handle sheath.

In a preferred embodiment, the variation range of the impedance of the tail end of the radio frequency ablation catheter is less than 25%, and the impedance of the tail end is not less than 20 ohms and not more than 500 ohms.

In a preferred embodiment, the cover portion includes a pressure limiting structure, and when the cover portion receives inward and outward pressure greater than a predetermined threshold, the pressure limiting structure can automatically release the locking of the cover portion and release the internal pressure.

In a preferred embodiment, the handle sheath comprises a transparent window for enabling a display device on the radiofrequency ablation module to be visually visible outside the handle sheath.

In a preferred embodiment, the handle sheath includes one or more buttons for controlling the rf ablation module.

In a preferred embodiment, the rf ablation module further comprises a modulation module, a fixed voltage transformation module, a buffer circuit, and an impedance matching network, wherein,

the impedance matching network is electrically coupled to a load of the radio frequency ablation catheter for matching an impedance of the load;

the fixed voltage conversion module is used for converting the direct-current voltage output by the battery into a preset direct-current voltage;

the modulation module is electrically coupled with the impedance matching network and the fixed voltage transformation module respectively and is used for modulating the direct current output by the fixed voltage transformation module into a pulse signal of rectangular wave, driving the load through the impedance matching network, and regulating and controlling the effective pulse width of the load through relatively translating the output complementary signal;

the buffer circuit is electrically coupled to the impedance matching network for absorbing transient signals caused by relative translation of the complementary signals.

In a preferred embodiment, the impedance matching network is an LC impedance transformation circuit.

In a preferred embodiment, the buffer circuit comprises a resistor and a capacitor connected in series and connected across two input terminals of the impedance matching network.

In a preferred embodiment, the modulation module comprises a push-pull driver and four field effect transistors;

among the four field effect transistors, a source electrode and a drain electrode of a first field effect transistor are respectively coupled to a first output end of the fixed voltage transformation module and a first input end of the LC impedance transformation circuit, a source electrode and a drain electrode of a second field effect transistor are respectively coupled to a second output end of the fixed voltage transformation module and a second input end of the LC impedance transformation circuit, a source electrode and a drain electrode of a third field effect transistor are respectively coupled to a first input end of the LC impedance transformation circuit and ground, and a source electrode and a drain electrode of a fourth field effect transistor are respectively coupled to a second input end of the LC impedance transformation circuit and ground;

and four output ends of the push-pull driver are electrically coupled with four gates of the four field effect transistors respectively, and are used for controlling the four field effect transistors to generate pulse signals in a push-pull mode and driving the load through the impedance matching network.

In a preferred embodiment, the fixed voltage conversion module comprises N stacked voltage boosting circuits, N sampling comparison circuits and a controller;

the first booster circuit comprises a field effect transistor and an inductor in the N booster circuits, wherein the grid electrode of the field effect transistor is the control end of the booster circuit, one end of the inductor is coupled with a battery, the other end of the inductor is coupled to a first node, the source electrode and the drain electrode of the field effect transistor are bridged between the first node and the ground, and the first node is the output end of the booster circuit;

each of the N boosting circuits except for the first boosting circuit comprises a field effect transistor, an inductor and a capacitor, wherein the grid electrode of the field effect transistor is a control end of the boosting circuit, one end of the inductor is coupled with a battery, the other end of the inductor is coupled to a second node, one end of the capacitor is coupled to the second node, the other end of the capacitor is an output end of the boosting circuit, and a source electrode and a drain electrode of the field effect transistor are connected between the second node and the ground in a bridging mode;

the output end of each booster circuit is coupled with the output end of the booster circuit on the upper layer through a diode, the output end of the booster circuit on the uppermost layer is coupled with the output end of the fixed voltage conversion module through a diode, and a capacitor is connected between the output end of the fixed voltage conversion module and the ground in a bridging manner;

each sampling comparison circuit comprises a current sampler and a comparator; the current sampler is used for sampling the current in the inductor of the corresponding booster circuit and outputting a sampling voltage signal; one input end of the comparator is coupled with the output end of the current sampler, the other input end of the comparator is coupled with a fixed voltage, and the output end of the comparator is coupled with the controller;

the N control output signals of the controller are respectively coupled with the control ends of the N boosting circuits and are used for controlling the N boosting circuits to realize boosting in a stacking relay mode according to signals output by the comparators in the N sampling comparison circuits.

In a preferred embodiment, the rf ablation module further includes a battery management circuit for controlling charging and discharging and safety of the battery.

In the embodiment of the disclosure, the sterile handle sheath is sterile, and although the rf ablation module is not sterile, by opening the cap of the handle sheath, placing the rf ablation module in the handle sheath, and then closing the cap of the handle sheath, an enclosed space capable of isolating the propagation of germs can be formed in the handle sheath, and the exterior of the handle sheath that can be contacted by a doctor is still sterile. Therefore, the requirement of sterile operation is met, and the problem that active parts of the radio frequency ablation module are damaged due to sterilization treatment is solved.

Furthermore, the transformer is replaced by the LC impedance conversion circuit, the variable output voltage conversion module which needs the transformer or a large inductor is replaced by the fixed voltage conversion module, the filtering of the LC circuit is omitted by replacing the sine wave electric signal with the pulse electric signal of the rectangular wave, and the power is controlled by replacing the voltage change with the pulse width modulation, so that the problem that the existing radio frequency ablation module depends on the transformer or the large inductor with a large volume is solved, and the miniaturization of the system is realized.

Further, the fixed voltage conversion module can adopt a laminated converter structure to distribute the output voltage to a plurality of layers, and the voltage born by the switching device of each layer is reduced, so that the volume of the fixed voltage conversion module can be greatly reduced.

The respective technical features disclosed in the above summary, the respective technical features disclosed in the following embodiments and examples, and the respective technical features disclosed in the drawings can be freely combined with each other to constitute various new technical solutions (which should be regarded as having been described in the present specification) unless such a combination of the technical features is technically impossible. For example, in one example, the feature a + B + C is disclosed, in another example, the feature a + B + D + E is disclosed, and the features C and D are equivalent technical means for the same purpose, and technically only one feature is used, but not simultaneously employed, and the feature E can be technically combined with the feature C, then the solution of a + B + C + D should not be considered as being described because the technology is not feasible, and the solution of a + B + C + E should be considered as being described.

Drawings

FIG. 1 is a schematic structural view of a cordless thermal ablation instrument according to one embodiment of the present disclosure;

FIG. 2 is a schematic view of a prior art RF ablation module;

FIG. 3 is a schematic diagram of impedance matching using an LC impedance matching network in one embodiment of the present disclosure;

FIG. 4 is a schematic view of a radio frequency ablation module according to one embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of a radio frequency ablation module according to one embodiment of the present disclosure;

FIG. 6 is a schematic structural view of a cordless thermal ablation instrument according to another embodiment of the present disclosure;

FIG. 7 is a waveform diagram illustrating a full load driving condition according to one embodiment of the present disclosure;

FIG. 8 is a waveform schematic in a non-full load driving state according to one embodiment of the present disclosure;

FIG. 9 is a schematic diagram of a fixed voltage conversion module according to one embodiment of the present disclosure;

FIG. 10 is a schematic diagram of a battery management circuit according to one embodiment of the present disclosure;

FIG. 11 is a schematic view of a pressure limiting structure according to one embodiment of the present disclosure.

Detailed Description

In the following description, numerous technical details are set forth in order to provide a better understanding of the present disclosure. However, it will be understood by those of ordinary skill in the art that the claimed embodiments of the present disclosure may be practiced without these specific details and with various changes and modifications based on the following embodiments.

To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

A first embodiment of the present disclosure is directed to a cordless thermal ablation instrument, as shown in fig. 1, comprising:

the rf ablation catheter 1 may be sterile, for example, and may be a disposable product or a product that can be sterilized and used multiple times.

And the handle sheath 2 is mechanically connected with the radio frequency ablation catheter. The handle sheath is also sterile, and may be, for example, a disposable product or a product that can be sterilized and used multiple times.

And the radio frequency ablation module 3 is used for providing radio frequency current to the radio frequency ablation catheter. The radiofrequency ablation module does not need sterilization and can be sterile.

The handle sheath comprises a hollow structure with a cover part 21 capable of being opened and closed, when the cover part is opened, the radio frequency ablation module can be installed in the handle sheath and electrically coupled with the radio frequency ablation catheter, and when the cover part is closed, the inner space of the handle sheath where the radio frequency ablation module is located is isolated from the outer part of the handle sheath in a sealing mode, so that the sterile environment outside the handle sheath cannot be influenced by the sterile environment in the inner space of the handle sheath. The radio frequency ablation module comprises a battery, and the radio frequency ablation catheter and the handle sheath do not comprise the battery. Optionally, in one embodiment, the portion of the cap 21 that engages the handle sheath 2 is provided with a sealing ring to ensure a sealing effect.

Optionally, in one embodiment, the tip impedance of the radiofrequency ablation catheter is substantially fixed. For example, the terminal impedance typically varies by less than 25%, and the terminal impedance typically is not less than 20 ohms, typically not more than 500 ohms.

Optionally, in one embodiment, the cover includes a pressure limiting structure that automatically unlocks the cover to release the internal pressure when the cover is subjected to an inward-outward pressure greater than a predetermined threshold. When the battery of the radiofrequency ablation module expands due to unexpected reasons, the pressure limiting structure can timely release the locking of the cover part to release the internal pressure, so that further damage is avoided. A specific example of the pressure limiting structure is shown in fig. 11. The pressure limiting structure comprises a pressure control spring 41, a pressure control buckle 42 and a sealing ring 43. When the pressure inside the handle sheath 2 exceeds the preset pressure of the pressure control spring 41, the pressure control buckle 42 moves leftwards, the cover part 21 is disengaged downwards, and the pressure inside the handle sheath is released. The user can also pry the press button 42 externally to move it to open the cover 21. The pressure limiting structure may be implemented in other ways, and is not necessarily limited to the way of fig. 11.

Optionally, in one embodiment, the handle sheath includes a transparent window 22 for enabling a display device (e.g., a liquid crystal display) on the rf ablation module to be visually visible outside of the handle sheath. The transparent window may be made of transparent plastic or glass.

Optionally, in some embodiments, the handle sheath includes one or more buttons 23 for controlling the radiofrequency ablation module. The button on the handle sheath can be implemented in a variety of ways. Optionally, in one embodiment, a button on the handle sheath may be electrically coupled to a radio frequency ablation module within the handle sheath. Optionally, in another embodiment, the button on the handle sheath corresponds in position to a physical button on the rf ablation module, and when the button on the handle sheath is pressed, the button on the handle sheath can apply pressure to the physical button on the rf ablation module, thereby activating the physical button on the rf ablation module.

Alternatively, in one embodiment, the rf ablation module 3 is configured as shown in fig. 5, and includes a 2-cell 18650 lithium battery 30, a battery management circuit 31, a controller circuit 32, a liquid crystal panel 33, and a connector 34 connected in series, enclosed in a housing 35. After the radiofrequency ablation module 3 is inserted into the handle sheath 2, the connector 34 is connected with an internal connector in the handle sheath 2, and the button 23 and the indicator light 24 on the handle sheath 2 are electrically connected with the connector 34 of the radiofrequency ablation module 3 through the internal connector.

The sterile handle sheath is sterile, although the radio frequency ablation module is not sterile, the cover of the handle sheath is closed after the sterile radio frequency ablation module is placed into the handle sheath by opening the cover of the handle sheath, a closed space capable of isolating the propagation of germs can be formed in the handle sheath, and the outside of the handle sheath which can be contacted by a doctor is still sterile. Therefore, the requirement of sterile operation is met, and the problem that active parts of the radio frequency ablation module are damaged due to sterilization is avoided.

Other variations of the structure of fig. 1 are possible. Optionally, in an embodiment, as shown in fig. 6, the handle may be split into two parts, and the two parts are connected by a flexible cable, wherein the first part is directly mounted with the rf ablation catheter, the second part is a hollow structure with a cover, when the cover is opened, the rf ablation module may be inserted into the hollow structure in the second part, and then the cover is closed, so that the second part forms a sealing structure, and the rf ablation module is sealed in the second part, so that the sterile environment outside the second part is not affected by the rf ablation module with bacteria. In this embodiment, the two portions of the handle are also sterile (which may be a disposable product, for example), and the rf ablation module does not require sterilization (which may be sterile).

Miniaturization of rf ablation modules is a difficult point. The prior art generally adopts an alternating current point of 220V or 110V as an energy source, and generates a controllable radio frequency signal after the energy is converted for multiple times and then inputs the radio frequency signal into a radio frequency guide pipe. Because the radio frequency ablation catheter is physically connected to high-voltage alternating current, the safety standard of medical equipment requires that multiple electrical isolation measures are adopted in the radio frequency generator, and various leakage currents, insulation distances and the like are forcibly required. This further hinders the miniaturization or even miniaturization of the design of the radiofrequency generator.

Fig. 2 shows a schematic circuit diagram of a conventional rf generator.

The conventional rf generator includes a variable output voltage conversion module, and controls output power by adjusting a voltage output from the voltage conversion module. In order to improve the efficiency, most of the voltage conversion modules with variable output are switch circuits, and the switch circuits comprise inductors with larger volumes, so that the problem of the independent generators with cabinets is solved, and the inductors protrude out of a circuit board when the independent generators are miniaturized, occupy too much space and hinder the miniaturization of the whole system.

The conventional rf transmitter also typically uses a class D power amplifier with a transformer as an output, one function of the transformer is to provide isolation to the conduit load, and the other function is to change the higher impedance transducer in the conduit load into a load that appears to the output power amplifier as a means of impedance matching, thereby reducing the voltage at the power amplifier end. The presence of the transformer further increases the circuit size and becomes a big obstacle in miniaturization design.

The conventional rf transmitter also filters the output signal of the transformer (e.g., using an LC filter circuit) to obtain a near sinusoidal signal for feedback measurement and control. LC filter circuits, especially the large inductance thereof, increase the circuit size and also hinder the miniaturization of the system.

In summary, the main reason that the conventional rf transmitter is not easily miniaturized is the use of a transformer and a large inductor.

The design of the radio frequency ablation module avoids the use of a transformer and a larger inductor, thereby greatly reducing the volume and enabling miniaturization. The main innovation points of the radio frequency ablation module of the present disclosure are as follows:

1. the voltage conversion circuit needing the inductor is abandoned, and the pulse width modulation is used for controlling the power, so that the space is saved.

2. Transient fluctuations caused by the pulse width modulation mechanism are eliminated by a buffer circuit.

3. And giving up the pursuit of a feedback Signal in a sine form, performing Fast Fourier Transform (FFT) through Digital Signal Processing (DSP), and extracting the phase and the amplitude of a corresponding frequency component, so that a hardware filter with a large size is omitted. How to extract the amplitude and phase of a specific frequency component using FFT is the prior art in the field and will not be described in detail here.

4. For applications with load impedances in a narrow range, such as load impedances of 20 ohms or 500 ohms with a deviation of less than 20% for some rf ablation catheters, the output transformer is eliminated and an LC impedance matching network is used to further reduce the circuit size. Fig. 3 shows a schematic diagram of impedance matching using an LC impedance matching network. The circuit on the left side of the LC impedance matching network is abstracted into a driving amplifier, the driving amplifier comprises a voltage source with voltage Vg and an internal resistance Rg, and the angular frequency of a voltage signal output by the voltage source is omega; the circuit on the right side of the LC impedance matching network is abstracted into a transducer model which comprises a resistor Rs and a capacitor Co which are connected in parallel; the LC impedance matching network includes an inductance Lm and a capacitance Cm. Wherein,

one embodiment of a radio frequency ablation module is shown in fig. 4, the radio frequency ablation module comprising a battery (not shown in fig. 4), a modulation module (including a push-pull driver and 4 fets), a fixed voltage transformation module, a buffer circuit, an impedance matching network, and a battery management circuit (not shown in fig. 4), wherein:

an impedance matching network is electrically coupled to a load of the radio frequency ablation catheter for matching an impedance of the load.

The fixed voltage conversion module is used for converting the direct-current voltage output by the battery into preset direct-current voltage, and the multiple of voltage change is fixed. For example, a dc boost circuit.

The modulation module is electrically coupled with the impedance matching network and the fixed voltage transformation module respectively and is used for modulating the direct current output by the fixed voltage transformation module into a pulse signal of rectangular wave, driving a load through the impedance matching network, and regulating and controlling the effective pulse width of the load through a complementary signal output by the relative translation.

The buffer circuit is electrically coupled to the impedance matching network for absorbing transient signals caused by relative translation of the complementary signals. Alternatively, in one embodiment, as shown in fig. 4, the buffer circuit comprises a resistor and a capacitor connected in series across two input terminals of the impedance matching network. In other embodiments, the buffer circuit may be in other forms as long as it can suppress the transient glitch signal.

The battery management circuit is used for controlling the charging and discharging of the battery and the safety. The battery may be a rechargeable battery, such as a lithium ion battery. When the radiofrequency ablation module is taken out of the handle sheath, the battery can be charged in a wired or wireless mode.

Optionally, in an embodiment, the impedance matching network is an LC impedance transformation circuit. In other embodiments, other forms may be used, so long as the impedance of the load of the rf ablation catheter can be matched.

Optionally, in an embodiment, the modulation module further includes a push-pull driver, and four field effect transistors. Of the four field effect transistors, a source and a drain of the first field effect transistor are respectively coupled to the first output terminal of the fixed voltage transformation module and the first input terminal of the LC impedance transformation circuit, a source and a drain of the second field effect transistor are respectively coupled to the second output terminal of the fixed voltage transformation module and the second input terminal of the LC impedance transformation circuit, a source and a drain of the third field effect transistor are respectively coupled to the first input terminal of the LC impedance transformation circuit and the ground, and a source and a drain of the fourth field effect transistor are respectively coupled to the second input terminal of the LC impedance transformation circuit and the ground.

Four output ends of the push-pull driver are respectively and electrically coupled with four grids of the four field effect transistors, and the push-pull driver is used for controlling the four field effect transistors to generate pulse signals in a push-pull mode and driving a load through an impedance matching network.

In other embodiments, the modulation module may be in other forms, for example, a push-pull driver may be used to drive two fets to generate the pulse signal.

Optionally, in another embodiment, the duty cycle of the 4 signal pulses A, B, C, D is changed to control the power output to the load. The larger the duty cycle, the greater the power output.

Alternatively, in one embodiment, the push-pull driver of fig. 4 has 4 output signals, forming two pairs of complementary signals (a-C versus B-D), and the power output to the load is controlled by adjusting the effective pulse width of the load by relatively shifting the complementary signals (fig. 7 is the waveform of the fully-driven state without shifting, and fig. 8 is the waveform of the non-fully-driven state after the B-D signal is shifted by Δ T relative to the a-C signal). The output power varies linearly with Δ T, the larger Δ T, the smaller the output power. Specifically, as shown in fig. 8, during Δ T, although A, C is high and 2 fets A, C are on, B, D is low and 2 fets B, D are off, there is no current on the catheter load. Only when the 4 signals A, B, C, D are all in high level state, the controlled 4 fets are all in on state, there is current on the catheter load. Therefore A, B, C, D these 4 signals can use exactly the same rectangular wave (e.g. square wave) without changing the waveform of any one signal, and the time that there is current on the catheter load can be easily controlled to control the actual power of the catheter load by controlling the relative time difference between a-C and B-D so that the duration of the 4 signals A, B, C, D all in the high state changes. During at the current is momentarily blocked and the resulting large amplitude transient signal (glitch) can be absorbed by the buffer circuit (i.e., the absorption network). Compared with the scheme of directly changing the pulse duty ratio, the scheme of the embodiment does not need to change the waveform of the pulse, and is lower in implementation cost.

The cordless design does not need an isolation transformer in the angle of safety isolation, and the isolation transformer is further eliminated from the angle of engineering realization by the circuit, so that the transformer is not needed to realize three functions of power regulation, impedance conversion and safety isolation on the premise of cordless. The variable output voltage converter needs a large output voltage range change, and often needs a transformer to realize a certain dynamic performance, and the design of the fixed output voltage converter only needs to improve the voltage to a fixed value in the application, so that the design is much simpler. Changing the variable output voltage DC-DC (DC stands for direct current) to a fixed output voltage DC-DC also further improves the possibility of avoiding the use of a transformer in the DC-DC circuit. Therefore, the combination of fixed supply voltage, pulse translation, impedance matching and absorption network forms a miniaturized driving power amplifier, which essentially eliminates a transformer and reduces the volume.

Alternatively, in one embodiment, the fixed voltage converter module may be implemented with a stacked converter configuration as shown in fig. 9.

The fixed voltage conversion module is a switch type boost converter. A typical boost converter includes a switching device, an inductor, and a capacitor, and utilizes the freewheeling characteristic of the inductor to perform voltage conversion. However, in the application scenario of the present disclosure, the fixed voltage conversion module generally needs to convert a voltage of about 7v of the battery pack into a direct current voltage of several hundreds of v, or even close to kilovolts, and therefore, a conventional switching device needs a high withstand voltage when selecting, resulting in a large volume of the selected switching device. The bulky switching device further brings big parasitic capacitance, forces switching frequency to become the step-down to make output fluctuate seriously, and supporting inductance and capacitance grow moreover, leads to whole circuit volume huge, and the big device brings the loss big simultaneously, and it is serious to generate heat, is unsuitable for totally enclosed miniature handheld device.

The present disclosure therefore proposes a stacked converter structure as shown in fig. 9, which distributes the output voltage over several layers, and the switching devices of each layer are thus subjected to a lower voltage. The 4-layer structures Q1-Q4 of FIG. 9 need only withstand Vout/4 voltage, respectively, and the volume can be greatly reduced.

The working principle of the circuit in fig. 9 is that when Q1 is turned on (Vg 1 is high), the current i1 on the inductor L1 increases, and when the corresponding current sampling signal reaches the specified voltage Vi of the controller, the output of the comparator turns over, so that the controller Vg1 becomes low, Q1 is turned off, and the current i1 decreases accordingly; vg1 becomes high, vg2 becomes high in 1/4 period, Q2 is turned on, so that the current i2 on the inductor L2 is increased, the voltage of the point A jumps to Vin/(1-D) after Q1 is turned off, D is the duty ratio, and therefore C2 is charged to Vin/(1-D); vg2 then goes low, Q2 turns off, and the voltage at point E becomes 2 Vin/(1-D), so capacitor C2 acts as a hold-up for the output voltage. In the same way, the voltage at the point E is boosted to 4 Vin/(1-D) after 4 layers of lamination. If the duty cycle is 85% and the battery voltage is 7.4V, vout =26.7 vin, the output Vout =197V, and Q1 only needs to bear less than 50V, a very small MOSFET tube may be selected.

The switching frequency of the whole converter control circuit can be improved by reducing the volume of the switching tube, and the volumes of the matched inductor and capacitor are further reduced; meanwhile, the loss can be reduced, the heat generation of the converter circuit is reduced, and the miniaturization and the sealing performance are facilitated.

For convenience of description, fig. 9 shows a 4-layer structure, the principle of which can be easily extended to an N-layer structure, where N is an integer greater than 1. The inputs i1-i4 of the comparator in fig. 9 represent sampled signals of the currents i1-i4 (which are a voltage signal), and sampling of the currents may be implemented using sampling resistors or other current sensors (sampling of the currents is prior art and is not shown in fig. 9). The above circuit can be implemented by a discrete device or by an integrated circuit.

Alternatively, in one embodiment, the battery management circuit may be implemented with a circuit as shown in fig. 10. The charging and discharging and transportation of lithium batteries in surgical instruments are required to ensure safety. The acceleration sensor of fig. 10 is used to determine whether the battery module has been transported, and if there is a vibration (e.g., the acceleration value output by the acceleration sensor exceeds a predetermined threshold), the battery is put to sleep (i.e., the external connection is disconnected, such as disconnecting the battery from the load). The over-voltage protection and the current sampling ensure the safety of charging and discharging. Lithium batteries cannot completely discharge electricity, otherwise the battery life is severely shortened. The BMS controller is provided with a battery capacity detection circuit, so that the electric quantity of the battery pack can be accurately detected and controlled; the charging and discharging circuit can ensure that charging and discharging do not interfere with each other.

It should be noted that in the disclosure, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the use of the verb "comprise a" to define an element does not exclude the presence of another, same element in a process, method, article, or apparatus that comprises the element. In the present disclosure, if it is mentioned that a certain action is performed according to a certain element, it means that the action is performed at least according to the element, and two cases are included: performing the action based only on the element, and performing the action based on the element and other elements. The expression of a plurality of, a plurality of and the like includes 2, 2 and more than 2, more than 2 and more than 2.

This specification includes combinations of the various embodiments described herein. Separate references to embodiments (e.g., "one embodiment" or "some embodiments" or "a preferred embodiment") do not necessarily refer to the same embodiment; however, these embodiments are not mutually exclusive, unless indicated as mutually exclusive or as would be apparent to one of ordinary skill in the art. It should be noted that the term "or" is used in this specification in a non-exclusive sense unless the context clearly dictates otherwise.

All documents mentioned in this disclosure are to be considered to be integrally included in the disclosure of the present disclosure so as to be subject to modification as necessary. Further, it is understood that various changes or modifications may be made to the disclosure by those skilled in the art after reading the disclosure, and such equivalents are also within the scope of the disclosure as claimed.

Claims (8)

1. A cordless rf ablation device, comprising:

the radio frequency ablation catheter has a tip impedance variation range of less than 25%, and the tip impedance is not less than 20 ohms and not more than 500 ohms;

a handle sheath mechanically connected to the radiofrequency ablation catheter;

the radiofrequency ablation module is used for providing radiofrequency current for the radiofrequency ablation catheter, comprises a battery and does not need sterilization before being used;

the handle sheath comprises a hollow structure with an openable cover part, a sealing device is arranged between the cover part and the handle sheath, when the cover part is opened, the radio frequency ablation module can be installed in the handle sheath and electrically coupled with the radio frequency ablation catheter, and when the cover part is closed, the inner space of the handle sheath where the radio frequency ablation module is located is sealed and isolated from the outer part of the handle sheath, so that the sterile environment of the outer part of the handle sheath cannot be influenced by the sterile environment of the inner space of the handle sheath;

the radiofrequency ablation module further comprises a modulation module, a fixed voltage transformation module, a buffer circuit, and an LC impedance transformation circuit, wherein,

the LC impedance transformation circuit is electrically coupled with a load of the radio frequency ablation catheter and used for matching the impedance of the load;

the fixed voltage conversion module is used for converting the direct-current voltage output by the battery into a preset direct-current voltage;

the modulation module is electrically coupled with the LC impedance conversion circuit and the fixed voltage conversion module respectively and is used for modulating the direct current output by the fixed voltage conversion module into a pulse signal of rectangular wave, driving the load through the LC impedance conversion circuit and regulating and controlling the effective pulse width of the load through relatively translating the output complementary signal;

the buffer circuit is electrically coupled to the LC impedance transformation circuit for absorbing transient signals caused by relative translation of the complementary signals.

2. The cordless rf ablation device of claim 1, wherein the cover includes a pressure limiting structure which automatically unlocks the cover to release internal pressure when the cover receives an inward and outward pressure greater than a predetermined threshold.

3. The cordless rf ablation instrument of claim 1, wherein the handle sheath includes a transparent window for enabling a display device on the rf ablation module to be visually visible outside the handle sheath.

4. The cordless rf ablation instrument of claim 1, wherein the handle sheath includes one or more buttons for controlling the rf ablation module.

5. The cordless rf ablation device of claim 1, wherein the snubber circuit comprises a resistor and a capacitor connected in series across the LC impedance transformation circuit between the two inputs.

6. The cordless rf ablation device of claim 1, wherein the modulation module comprises a push-pull driver, and four field effect transistors;

among the four field effect transistors, a source electrode and a drain electrode of a first field effect transistor are respectively coupled to a first output end of the fixed voltage conversion module and a first input end of the LC impedance conversion circuit, a source electrode and a drain electrode of a second field effect transistor are respectively coupled to a second output end of the fixed voltage conversion module and a second input end of the LC impedance conversion circuit, a source electrode and a drain electrode of a third field effect transistor are respectively coupled to a first input end of the LC impedance conversion circuit and ground, and a source electrode and a drain electrode of a fourth field effect transistor are respectively coupled to a second input end of the LC impedance conversion circuit and ground;

and four output ends of the push-pull driver are electrically coupled with four gates of the four field effect transistors respectively, and are used for controlling the four field effect transistors to generate pulse signals in a push-pull mode, and the load is driven through the LC impedance transformation circuit.

7. The cordless rf ablation device of claim 1, wherein the fixed voltage conversion module comprises N stacked boost circuits, N sample-and-compare circuits and a controller;

in the N boosting circuits, a first boosting circuit comprises a field effect transistor and an inductor, wherein a grid electrode of the field effect transistor is a control end of the boosting circuit, one end of the inductor is coupled with a battery, the other end of the inductor is coupled to a first node, a source electrode and a drain electrode of the field effect transistor are bridged between the first node and the ground, and the first node is an output end of the boosting circuit;

each of the N boosting circuits except for the first boosting circuit comprises a field effect transistor, an inductor and a capacitor, wherein the grid electrode of the field effect transistor is a control end of the boosting circuit, one end of the inductor is coupled with a battery, the other end of the inductor is coupled to a second node, one end of the capacitor is coupled to the second node, the other end of the capacitor is an output end of the boosting circuit, and a source electrode and a drain electrode of the field effect transistor are connected between the second node and the ground in a bridging mode;

the output end of each booster circuit is coupled with the output end of the booster circuit on the upper layer through a diode, the output end of the booster circuit on the uppermost layer is coupled with the output end of the fixed voltage conversion module through a diode, and a capacitor is connected between the output end of the fixed voltage conversion module and the ground in a bridging manner;

each sampling comparison circuit comprises a current sampler and a comparator; the current sampler is used for sampling the current in the inductor of the corresponding booster circuit and outputting a sampling voltage signal; one input end of the comparator is coupled with the output end of the current sampler, the other input end of the comparator is coupled with a fixed voltage, and the output end of the comparator is coupled with the controller;

the N control output signals of the controller are respectively coupled with the control ends of the N boosting circuits and are used for controlling the N boosting circuits to realize boosting in a stacking relay mode according to signals output by the comparators in the N sampling comparison circuits.

8. The cordless rf ablation device of claim 1, wherein the rf ablation module further comprises a battery management circuit for controlling the charging and discharging and safety of the battery.

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