Lightning protection circuit, impedance matcher and plasma generation equipment

Abstract

The utility model discloses a lightning protection circuit, an impedance matcher and plasma generation equipment, and relates to the technical field of lightning protection. The controlled end of the switching circuit is electrically connected with the control end of the main control circuit; the first ends of the plurality of bleeder circuits are electrically connected with the first input end of the impedance matching circuit through the switching circuit, the second ends of the plurality of bleeder circuits are electrically connected with the second input end of the impedance matching circuit, and the third ends of the plurality of bleeder circuits are grounded; the output ends of the plurality of over-temperature protection circuits are electrically connected with the signal receiving end of the main control circuit; the utility model aims to solve the technical problems that when the lightning protection circuit is aged, the lightning protection effect is poor, and safety accidents such as fire disasters can be caused.

Description

Technical Field

[0001] The utility model relates to the technical field of lightning protection, in particular to a lightning protection circuit, an impedance matcher and a plasma generating device. Background Art

[0002] The plasma generating equipment includes a plasma chamber and an RF power supply. The impedance of the nonlinear load in the plasma chamber is not equal to the constant output impedance of the RF power supply. Therefore, there is a serious impedance mismatch between the RF power supply and the plasma chamber, resulting in a large amount of reflected power on the transmission line. The power generated by the RF power supply cannot be fully transmitted to the plasma chamber, resulting in a large power loss.

[0003] To solve this problem, the impedance matching network in the RF power supply system is adjusted so that the sum of the impedance of the matching network and the impedance of the nonlinear load in the plasma chamber is equal to the impedance of the RF power supply, thereby achieving impedance matching and achieving maximum output power.

[0004] During thunderstorms, if plasma generating equipment is used in areas with high altitudes, it is prone to lightning strikes. If the plasma generating equipment does not take effective lightning protection measures, lightning may directly strike the equipment, causing damage to the internal circuits of the equipment, or even causing fires or explosions. Therefore, existing plasma generating equipment is generally equipped with lightning protection circuits. However, existing lightning protection circuits are prone to aging. Once aged, the lightning protection effect of the lightning protection circuit is poor. When lightning surges flow into the aged lightning protection circuit, the temperature of the lightning protection circuit is likely to rise sharply. The excessively high temperature will affect the normal operation of surrounding circuits and may even cause safety accidents such as fires. Utility Model Content

[0005] The main purpose of the utility model is to propose a lightning protection circuit, an impedance matcher and a plasma generating device, aiming to solve the technical problem that when the lightning protection circuit ages, the lightning protection effect is poor and safety accidents such as fire may occur.

[0006] To achieve the above objectives, the present invention proposes a lightning protection circuit, which is applied to a plasma generating device. The plasma generating device includes a radio frequency power supply, an impedance matching circuit, and a plasma chamber. The positive and negative electrodes of the radio frequency power supply are electrically connected to the first input terminal and the second input terminal of the impedance matching circuit, respectively. The first output terminal and the second output terminal of the impedance matching circuit are both used to electrically connect to the electrodes of the plasma chamber. The lightning protection circuit includes:

[0007] Main control circuit;

[0008] a switch circuit, wherein a controlled end of the switch circuit is electrically connected to a control end of the main control circuit;

[0009] a plurality of discharge circuits, wherein first ends of the plurality of discharge circuits are electrically connected to the first input end of the impedance matching circuit via the switch circuit, second ends of the plurality of discharge circuits are electrically connected to the second input end of the impedance matching circuit, and third ends of the plurality of discharge circuits are grounded;

[0010] When a lightning surge flows into the first input terminal and the second input terminal of the impedance matching circuit, the discharge circuit is used to discharge the lightning surge to the ground;

[0011] a plurality of over-temperature protection circuits, wherein the output ends of the plurality of over-temperature protection circuits are electrically connected to the signal receiving end of the main control circuit;

[0012] Each of the over-temperature protection circuits is used to detect the temperature of the corresponding discharge circuit. When the temperature of one of the discharge circuits is greater than a preset temperature, the corresponding over-temperature protection circuit outputs a corresponding control signal, so that the main control circuit controls the switch circuit to disconnect the path between the corresponding discharge circuit and the first input end of the impedance matching circuit, and to connect the path between the other discharge circuit and the first input end of the impedance matching circuit.

[0013] In one embodiment, the discharge circuit includes:

[0014] A varistor circuit, wherein a first end of the varistor circuit is electrically connected to the first input end of the impedance matching circuit via the switching circuit, a second end of the varistor circuit is electrically connected to the second input end of the impedance matching circuit, and a third end of the varistor circuit is grounded.

[0015] In one embodiment, the over-temperature protection circuit includes:

[0016] A temperature fuse circuit and a photoelectric coupler circuit, wherein the temperature fuse circuit is arranged around the varistor circuit and blows when the temperature of the varistor circuit is greater than a preset temperature; a first end of the temperature fuse circuit is connected to a first voltage-stabilizing source, a second end of the temperature fuse circuit is electrically connected to the input end of the photoelectric coupler circuit, and an output end of the photoelectric coupler circuit is electrically connected to the signal receiving end of the main control circuit.

[0017] In one embodiment, the piezoresistive resistor circuit includes:

[0018] A first varistor, a second varistor, a third varistor and a ceramic gas discharge tube, wherein the first end of the first varistor and the first end of the third varistor are both electrically connected to the first input end of the impedance matching circuit via the switching circuit, the second end of the first varistor is electrically connected to the second input end of the impedance matching circuit, the first end of the second varistor is electrically connected to the second input end of the impedance matching circuit, the second end of the second varistor and the second end of the third varistor are both electrically connected to the first end of the ceramic gas discharge tube, and the second end of the ceramic gas discharge tube is grounded.

[0019] In one embodiment, the optocoupler circuit includes:

[0020] A voltage regulator diode, a first resistor, a second resistor, a first capacitor and a photoelectric coupler, wherein the cathode of the voltage regulator diode is electrically connected to the second end of the temperature fuse circuit and the first end of the first resistor respectively, the second end of the first resistor is electrically connected to the first end of the first capacitor, the first end of the first capacitor is also electrically connected to the anode of the photodiode of the photoelectric coupler, the anode of the voltage regulator diode, the second end of the first capacitor and the cathode of the photodiode of the photoelectric coupler are electrically connected, the input end of the phototransistor of the photocoupler is electrically connected to the second end of the second resistor and the signal receiving end of the main control circuit respectively, the first end of the second resistor is connected to a second voltage regulator source, and the output end of the phototransistor of the photocoupler is grounded.

[0021] In one embodiment, the lightning protection circuit includes:

[0022] A first inductor and a second inductor, wherein a first end of the first inductor is electrically connected to the first output end of the impedance matching circuit, a first end of the second inductor is electrically connected to the second output end of the impedance matching circuit, and a second end of the first inductor and a second end of the second inductor are both electrically connected to an electrode of the plasma chamber.

[0023] In one embodiment, the lightning protection circuit further includes:

[0024] a second capacitor, a third capacitor and a fourth capacitor, wherein the first end of the first inductor is electrically connected to the first end of the second capacitor and the first end of the third capacitor respectively, the second end of the second inductor is electrically connected to the second end of the second capacitor and the second end of the fourth capacitor respectively, the second end of the third capacitor and the second end of the fourth capacitor are both grounded, and the first end of the third capacitor and the second end of the fourth capacitor are both electrically connected to the electrode of the plasma chamber.

[0025] The utility model also provides an impedance matcher, comprising an impedance matching circuit and any one of the above-mentioned lightning protection circuits.

[0026] The utility model also provides a plasma generating device, comprising a plasma chamber and the impedance matching device described above.

[0027] The lightning protection circuit of the utility model includes multiple discharge circuits, switch circuits and multiple over-temperature protection circuits. When the plasma generating device is struck by lightning, so that the lightning surge flows into the first input terminal and the second input terminal of the impedance matching circuit, the discharge circuit connected to the first input terminal can discharge the lightning surge to the ground, thereby preventing the lightning surge from entering the subsequent circuit, effectively reducing the risk of damage to the equipment due to lightning strikes. Moreover, when one of the discharge circuits ages and causes its temperature to rise sharply when discharging the lightning surge, if the temperature exceeds a preset value, the corresponding over-temperature protection circuit outputs a corresponding control signal to the main control circuit, so that the main control circuit controls the switch circuit to disconnect the discharge circuit from the impedance matching circuit. The lightning protection circuit of the utility model is configured to connect the first input terminal of the lightning protection circuit with the discharge circuit of the first input terminal of the impedance matching circuit and conduct the path between the discharge circuit of the first input terminal of the impedance matching circuit. With such an arrangement, in actual application, when one of the discharge circuits ages and the temperature rises, the lightning protection circuit of the utility model can promptly disconnect the path between the discharge circuit of the overly high temperature and the impedance matching circuit, and replace it with another normal discharge circuit. Compared with the existing lightning protection circuit, the lightning protection circuit of the utility model can promptly replace the other discharge circuit before one of the discharge circuits ages and causes an excessively high temperature, so that the lightning protection circuit can still achieve a normal lightning protection effect, and will not affect the internal circuit due to excessive temperature and cause safety accidents such as fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0029] Figure 1 This is a schematic diagram of a module according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of a module of another embodiment of the present utility model;

[0031] Figure 3 This is a module diagram of another embodiment of the present utility model;

[0032] Figure 4 This is a schematic diagram of the circuit structure of another embodiment of the present utility model;

[0033] Figure 5This is a schematic diagram of the circuit structure of another embodiment of the present utility model;

[0034] Description of Figure Numbers:

[0035] 10. Main control circuit; 20. Switching circuit; 30. Discharge circuit; 31. Varistor circuit; 40. Over-temperature protection circuit; 40. Over-temperature protection circuit; 41. Thermal fuse circuit; 42. Optocoupler circuit.

[0036] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0038] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0039] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0040] The plasma generating equipment includes a plasma chamber and an RF power supply. The impedance of the nonlinear load in the plasma chamber is not equal to the constant output impedance of the RF power supply. Therefore, there is a serious impedance mismatch between the RF power supply and the plasma chamber, resulting in a large amount of reflected power on the transmission line. The power generated by the RF power supply cannot be fully transmitted to the plasma chamber, resulting in a large power loss.

[0041] To solve this problem, the impedance matching network in the RF power supply system is adjusted so that the sum of the impedance of the matching network and the impedance of the nonlinear load in the plasma chamber is equal to the impedance of the RF power supply, thereby achieving impedance matching and achieving maximum output power.

[0042] However, existing plasma generating equipment usually does not have lightning protection functions. In thunderstorm weather, if it is used in areas with high altitudes, it is prone to lightning strikes. If the plasma generating equipment does not take effective lightning protection measures, lightning may directly hit the equipment, causing damage to the internal circuit of the equipment, or even causing a fire or explosion. The surge voltage generated by lightning may interfere with the normal working signals of the plasma generating equipment, causing the equipment to fail to operate according to the predetermined program, thereby affecting its production efficiency and product quality.

[0043] To this end, the present invention proposes a lightning protection circuit, an impedance matcher, and a plasma generating device, which are intended to prevent lightning strikes from damaging a plasma device or interfering with the normal operation of the plasma device.

[0044] refer to Figures 1 to 5 The utility model provides a lightning protection circuit for use in a plasma generating device. The plasma generating device includes a radio frequency power supply, an impedance matching circuit, and a plasma chamber. The positive and negative electrodes of the radio frequency power supply are electrically connected to a first input terminal and a second input terminal of the impedance matching circuit, respectively. The first output terminal and the second output terminal of the impedance matching circuit are both electrically connected to electrodes of the plasma chamber. The lightning protection circuit includes:

[0045] Main control circuit 10;

[0046] A switch circuit 20, wherein a controlled end of the switch circuit 20 is electrically connected to a control end of the main control circuit 10;

[0047] a plurality of discharge circuits 30, wherein first ends of the plurality of discharge circuits 30 are electrically connected to the first input end of the impedance matching circuit via the switch circuit 20, second ends of the plurality of discharge circuits 30 are electrically connected to the second input end of the impedance matching circuit, and third ends of the plurality of discharge circuits 30 are grounded;

[0048] When a lightning surge flows into the first input terminal and the second input terminal of the impedance matching circuit, the discharge circuit 30 is used to discharge the lightning surge to the ground;

[0049] A plurality of over-temperature protection circuits 40, wherein the output ends of the plurality of over-temperature protection circuits 40 are electrically connected to the signal receiving end of the main control circuit 10;

[0050] Each over-temperature protection circuit 40 is used to detect the temperature of the corresponding discharge circuit 30. When the temperature of one of the discharge circuits 30 is greater than a preset temperature, the corresponding over-temperature protection circuit 40 outputs a corresponding control signal to cause the main control circuit 10 to control the switch circuit 20 to disconnect the path between the corresponding discharge circuit 30 and the first input end of the impedance matching circuit, and to connect the path between the other discharge circuit 30 and the first input end of the impedance matching circuit.

[0051] In this embodiment, the main control circuit 10 can be implemented by a main controller, such as an MCU (Microcontroller Unit), a DSP (Digital Signal Process), an FPGA (Field Programmable Gate Array), a SOC (System On Chip), etc.

[0052] In this embodiment, the impedance matching circuit can adopt one of an L-type impedance matching circuit, a T-type impedance matching circuit or a Π-type impedance matching circuit. The L-type matching circuit is usually composed of an inductor and a capacitor, and these two elements can be connected in series or in parallel; the T-type network impedance matching circuit is composed of two inductors connected in series and two capacitors connected in parallel; the Π-type network impedance matching circuit is composed of two capacitors connected in parallel and two inductors connected in series. By adjusting the values ​​of the inductor and the capacitor, the impedance of the signal source and the impedance of the load can be converted into matching impedances, thereby achieving maximum power transmission and minimum reflection loss.

[0053] In this embodiment, the switching circuit 20 uses multiple single-pole single-throw switches, one end of the single-pole single-throw switch is electrically connected to the first end of the discharge circuit 30, the other end of the single-pole single-throw switch is electrically connected to the first input end of the impedance matching circuit, and the controlled end of the single-pole single-throw switch is electrically connected to the control end of the main control circuit 10.

[0054] Specifically, the lightning protection circuit of the present invention includes multiple discharge circuits 30, a switch circuit 20 and multiple over-temperature protection circuits 40. When the plasma generating device is struck by lightning, so that the lightning surge flows into the first input terminal and the second input terminal of the impedance matching circuit, the discharge circuit 30 connected to the first input terminal can discharge the lightning surge to the ground, thereby preventing the lightning surge from entering the subsequent circuit, effectively reducing the risk of damage to the equipment due to lightning strikes, and when one of the discharge circuits 30 ages and causes its temperature to rise sharply when discharging the lightning surge, if the temperature exceeds a preset value, the corresponding over-temperature protection circuit 40 outputs a corresponding control signal to the main control circuit 10, so that the main control circuit 10 controls the switch circuit 20 to disconnect the discharge circuit 30 from the impedance matching circuit. The path between the first input end of the impedance matching circuit is connected, and the path between another normal discharger circuit 30 and the first input end of the impedance matching circuit is connected. With such an arrangement, in actual application, when one of the discharger circuits 30 ages and the temperature rises, the lightning protection circuit of the present invention can promptly disconnect the path between the discharger circuit 30 with too high a temperature and the impedance matching circuit, and replace it with another normal discharger circuit 30. Compared with the existing lightning protection circuit, the lightning protection circuit of the present invention can promptly replace the other discharger circuit 30 before one of the discharger circuits 30 ages and causes an excessively high temperature, so that the lightning protection circuit can still achieve a normal lightning protection effect, and will not affect the internal circuit due to excessive temperature and cause safety accidents such as fire.

[0055] refer to Figure 2 In one embodiment of the present invention, the discharge circuit 30 includes:

[0056] The varistor circuit 31 has a first end electrically connected to the first input end of the impedance matching circuit via the switch circuit 20, a second end electrically connected to the second input end of the impedance matching circuit, and a third end grounded.

[0057] In this embodiment, the varistor circuit 31 uses multiple varistors. Since the resistance of the varistor is extremely large under normal circumstances, the varistor circuit 31 is equivalent to an open circuit under normal circumstances and does not affect the normal operation of the plasma generating device. When an overvoltage (such as a lightning surge) occurs in the circuit, the voltage across the varistor rises rapidly. When the voltage exceeds the threshold voltage of the varistor, the impedance of the varistor drops sharply, which is equivalent to a short circuit, thereby guiding the lightning surge to the ground, thereby protecting the discharge circuit 30 and the device from damage. If one or more varistors in one of the varistor circuits 31 increase in temperature due to aging when a lightning surge flows in, the overtemperature protection circuit 40 disconnects the path between the varistor circuit 31 and the first input end of the impedance matching circuit, and connects the path between the other varistor circuit 31 and the first input end of the impedance matching circuit.

[0058] Furthermore, the over-temperature protection circuit 40 includes:

[0059] A temperature fuse circuit 41 and a photocoupler circuit 42, the temperature fuse circuit 41 is arranged around the varistor circuit 31, and when the temperature of the varistor circuit 31 is greater than a preset temperature, the temperature fuse circuit 41 melts; the first end of the temperature fuse circuit 41 is connected to the first voltage stabilization source, the second end of the temperature fuse circuit 41 is electrically connected to the input end of the photocoupler circuit 42, and the output end of the photocoupler circuit 42 is electrically connected to the signal receiving end of the main control circuit 10.

[0060] In this embodiment, the temperature fuse circuit 41 uses the same number of temperature fuses F1 as the number of varistors in the varistor circuit 31. Since the temperature fuse circuit 41 is arranged around the varistor circuit 31, the temperature fuse and the varistor have a good thermal coupling effect. When one of the varistors ages and its temperature reaches the melting point of the temperature fuse, the corresponding temperature fuse blows, and the current of the first voltage-stabilizing source cannot be output to the photoelectric coupler circuit 42. If the photoelectric coupler circuit 42 does not receive the current output by the first voltage-stabilizing source, it outputs a corresponding control signal to the main control circuit 10, so that the main control circuit 10 controls the switch circuit 20 to disconnect the path between the corresponding discharge circuit 30 and the first input end of the impedance matching circuit. Among them, the optocoupler circuit 42 uses at least one optocoupler, which can play a role in electrical isolation. Since lightning surges are often accompanied by strong electromagnetic interference and noise, if the over-temperature protection circuit 40 directly outputs the control signal to the main control circuit 10, electromagnetic interference and noise may enter the main control circuit 10 together with the control signal, and electromagnetic interference and noise will affect the normal operation of the main control circuit 10. The electrical isolation function of the optocoupler can reduce the impact of electromagnetic interference and noise on the main control circuit 10, thereby improving the stability and reliability of the circuit.

[0061] For further reference, Figure 3 , the varistor circuit 31 includes:

[0062] A first varistor R1, a second varistor R2, a third varistor R3 and a ceramic gas discharge tube EA, the first end of the first varistor R1 and the first end of the third varistor R3 are both electrically connected to the first input end of the impedance matching circuit via the switching circuit 20, the second end of the first varistor R1 is electrically connected to the second input end of the impedance matching circuit, the first end of the second varistor R2 is electrically connected to the second input end of the impedance matching circuit, the second end of the second varistor R2 and the second end of the third varistor R3 are both electrically connected to the first end of the ceramic gas discharge tube EA, and the second end of the ceramic gas discharge tube EA is grounded.

[0063] In this embodiment, when the varistor fails due to aging or other reasons, if the current passing through the varistor is too large, the temperature of the first varistor R1 will rise sharply. The excessively high temperature will melt the first temperature fuse, so that the circuit is quickly cut off before the varistor catches fire, thereby preventing the excessively high temperature of the varistor from affecting the surrounding circuit structure and even causing accidents such as fire. Under normal circumstances, the ceramic gas discharge tube EA has a very large resistance, which is equivalent to an open circuit, with no leakage current or very small leakage current; in the case of overvoltage, it will quickly discharge and conduct, discharging the overvoltage to the ground.

[0064] For further reference, Figure 4 , the optocoupler circuit 42 includes:

[0065] A voltage regulator diode D1, a first resistor RF1, a second resistor RF2, a first capacitor C1 and a photoelectric coupler U1, the cathode of the voltage regulator diode D1 is electrically connected to the second end of the temperature fuse circuit 41 and the first end of the first resistor RF1 respectively, the second end of the first resistor RF1 is electrically connected to the first end of the first capacitor C1, the first end of the first capacitor C1 is also electrically connected to the anode of the photodiode of the photoelectric coupler U1, the anode of the voltage regulator diode D1, the second end of the first capacitor C1 and the cathode of the photodiode of the photoelectric coupler U1 are electrically connected, the input end of the phototransistor of the photoelectric coupler U1 is electrically connected to the second end of the second resistor RF2 and the signal receiving end of the main control circuit 10 respectively, the first end of the second resistor RF2 is connected to the second voltage regulator source, and the output end of the phototransistor of the photoelectric coupler U1 is grounded.

[0066] In this embodiment, under normal circumstances, the temperature fuse circuit 41 is not open, the current output by the first voltage-stabilizing source passes through the photodiode to make the photodiode emit light, and accordingly, the phototransistor is also turned on, and the current output by the second voltage-stabilizing source is output to the ground through the phototransistor, so that the signal receiving end of the main control circuit 10 cannot receive the current of the second voltage-stabilizing source; when the temperature of one of the varistor circuits 31 is too high and causes the temperature fuse circuit 41 to open, the photodiode goes out to turn off the phototransistor, and the current of the second voltage-stabilizing source is output to the signal receiving end of the main control circuit 10. After receiving the current from the second voltage-stabilizing source, the main control circuit 10 controls the switch circuit 20 to disconnect the path between the varistor circuit 31 and the first input end of the impedance matching.

[0067] refer to Figure 5 In one embodiment of the present invention, the lightning protection circuit includes:

[0068] A first inductor L1 and a second inductor L2, wherein a first end of the first inductor L1 is electrically connected to a first output end of the impedance matching circuit, a first end of the second inductor L2 is electrically connected to a second output end of the impedance matching circuit, and a second end of the first inductor L1 and a second end of the second inductor L2 are both electrically connected to an electrode of the plasma chamber.

[0069] In this embodiment, the first inductor L1 and the second inductor L2 form a common-mode filter circuit. The common-mode inductor can effectively suppress common-mode interference signals generated in the circuit due to sudden voltage, lightning strikes, etc. When the common-mode interference signal enters the circuit, the common-mode inductor will use the principle of electromagnetic induction to generate an induced electromotive force on the inductor, thereby forming a reverse current. The reverse current will offset the common-mode interference signal and achieve the purpose of suppressing interference.

[0070] Furthermore, the lightning protection circuit also includes:

[0071] The second capacitor C2, the third capacitor C3 and the fourth capacitor C4, the first end of the first inductor L1 is electrically connected to the first end of the second capacitor C2 and the first end of the third capacitor C3 respectively, the second end of the second inductor L2 is electrically connected to the second end of the second capacitor C2 and the second end of the fourth capacitor C4 respectively, the second end of the third capacitor C3 and the second end of the fourth capacitor C4 are both grounded, and the first end of the third capacitor C3 and the second end of the fourth capacitor C4 are both electrically connected to the electrodes of the plasma chamber.

[0072] In this embodiment, the second capacitor C2 is a safety X-type capacitor, which is connected between the first output terminal and the second output terminal of the impedance matching circuit to suppress differential mode interference input to the plasma chamber. The third capacitor C3 and the fourth capacitor C4 are both safety Y-type capacitors. The third capacitor C3 and the fourth capacitor C4 are both used to filter out common mode interference in the signal. When a common mode interference signal appears, the third capacitor C3 and the fourth capacitor C4 will provide a low impedance path, allowing most of the common mode noise to flow directly to the ground through the capacitors instead of being input into the plasma chamber.

[0073] The utility model also provides an impedance matcher, which comprises an impedance matching circuit and the above-mentioned lightning protection circuit.

[0074] It is worth noting that since the impedance matcher of the present invention is based on the above-mentioned lightning protection circuit, the embodiments of the impedance matcher of the present invention include all technical solutions of all embodiments of the above-mentioned lightning protection circuit, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0075] The utility model also provides a plasma generating device, comprising the impedance matching device as described above.

[0076] It is worth noting that since the plasma generating device of the present invention is based on the above-mentioned impedance matcher, the embodiments of the plasma generating device of the present invention include all technical solutions of all embodiments of the above-mentioned impedance matcher, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0077] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A lightning protection circuit, applied to a plasma generating device, the plasma generating device comprising a radio frequency power supply, an impedance matching circuit, and a plasma chamber, wherein the positive and negative electrodes of the radio frequency power supply are electrically connected to the first input terminal and the second input terminal of the impedance matching circuit, respectively, and the first output terminal and the second output terminal of the impedance matching circuit are both electrically connected to the electrodes of the plasma chamber, characterized in that: The lightning protection circuit comprises: Main control circuit; a switch circuit, wherein a controlled end of the switch circuit is electrically connected to a control end of the main control circuit; a plurality of discharge circuits, wherein first ends of the plurality of discharge circuits are electrically connected to the first input end of the impedance matching circuit via the switch circuit, second ends of the plurality of discharge circuits are electrically connected to the second input end of the impedance matching circuit, and third ends of the plurality of discharge circuits are grounded; When a lightning surge flows into the first input terminal and the second input terminal of the impedance matching circuit, the discharge circuit is used to discharge the lightning surge to the ground; a plurality of over-temperature protection circuits, wherein the output ends of the plurality of over-temperature protection circuits are electrically connected to the signal receiving end of the main control circuit; Each of the over-temperature protection circuits is used to detect the temperature of the corresponding discharge circuit. When the temperature of one of the discharge circuits is greater than a preset temperature, the corresponding over-temperature protection circuit outputs a corresponding control signal, so that the main control circuit controls the switch circuit to disconnect the path between the corresponding discharge circuit and the first input end of the impedance matching circuit, and to connect the path between the other discharge circuit and the first input end of the impedance matching circuit.

2. The lightning protection circuit according to claim 1, characterized in that: The discharge circuit includes: A varistor circuit, wherein a first end of the varistor circuit is electrically connected to the first input end of the impedance matching circuit via the switching circuit, a second end of the varistor circuit is electrically connected to the second input end of the impedance matching circuit, and a third end of the varistor circuit is grounded.

3. The lightning protection circuit according to claim 2, characterized in that: The over-temperature protection circuit includes: A temperature fuse circuit and a photoelectric coupler circuit, wherein the temperature fuse circuit is arranged around the varistor circuit and blows when the temperature of the varistor circuit is greater than a preset temperature; a first end of the temperature fuse circuit is connected to a first voltage-stabilizing source, a second end of the temperature fuse circuit is electrically connected to the input end of the photoelectric coupler circuit, and an output end of the photoelectric coupler circuit is electrically connected to the signal receiving end of the main control circuit.

4. The lightning protection circuit according to claim 3, characterized in that: The varistor circuit comprises: A first varistor, a second varistor, a third varistor and a ceramic gas discharge tube, wherein the first end of the first varistor and the first end of the third varistor are both electrically connected to the first input end of the impedance matching circuit via the switching circuit, the second end of the first varistor is electrically connected to the second input end of the impedance matching circuit, the first end of the second varistor is electrically connected to the second input end of the impedance matching circuit, the second end of the second varistor and the second end of the third varistor are both electrically connected to the first end of the ceramic gas discharge tube, and the second end of the ceramic gas discharge tube is grounded.

5. The lightning protection circuit according to claim 4, characterized in that: The photocoupler circuit comprises: A voltage regulator diode, a first resistor, a second resistor, a first capacitor and a photoelectric coupler, wherein the cathode of the voltage regulator diode is electrically connected to the second end of the temperature fuse circuit and the first end of the first resistor respectively, the second end of the first resistor is electrically connected to the first end of the first capacitor, the first end of the first capacitor is also electrically connected to the anode of the photodiode of the photoelectric coupler, the anode of the voltage regulator diode, the second end of the first capacitor and the cathode of the photodiode of the photoelectric coupler are electrically connected, the input end of the phototransistor of the photocoupler is electrically connected to the second end of the second resistor and the signal receiving end of the main control circuit respectively, the first end of the second resistor is connected to a second voltage regulator source, and the output end of the phototransistor of the photocoupler is grounded.

6. The lightning protection circuit according to claim 1, characterized in that: The lightning protection circuit comprises: A first inductor and a second inductor, wherein a first end of the first inductor is electrically connected to the first output end of the impedance matching circuit, a first end of the second inductor is electrically connected to the second output end of the impedance matching circuit, and a second end of the first inductor and a second end of the second inductor are both electrically connected to an electrode of the plasma chamber.

7. The lightning protection circuit according to claim 6, characterized in that: The lightning protection circuit also includes: a second capacitor, a third capacitor and a fourth capacitor, wherein the first end of the first inductor is electrically connected to the first end of the second capacitor and the first end of the third capacitor respectively, the second end of the second inductor is electrically connected to the second end of the second capacitor and the second end of the fourth capacitor respectively, the second end of the third capacitor and the second end of the fourth capacitor are both grounded, and the first end of the third capacitor and the second end of the fourth capacitor are both electrically connected to the electrode of the plasma chamber.

8. An impedance matching box, characterized in that: The invention comprises an impedance matching circuit and a lightning protection circuit according to any one of claims 1 to 7.

9. A plasma generating device, characterized in that: The device comprises a plasma chamber and the impedance matching box as claimed in claim 8.

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