Marx generator and operation method thereof

Abstract

The invention belongs to the technical field of pulse power, and particularly discloses a Marx generator and an operation method thereof. The Marx generator comprises a double-sided PCB (Printed Circuit Board) and N stages of charge-discharge cascade units which are connected in sequence, in the N stages of charge-discharge cascade units, the first units with an odd cascade sequence are sequentially arranged on one surface of the double-sided PCB, and the second units with an even cascade sequence are sequentially arranged on the other surface of the double-sided PCB; each first unit is electrically connected with a second unit which is adjacently connected with the first unit through a through hole preset in the double-sided PCB, and the first-stage unit in the N-stage charge-discharge cascade units drives the generator to perform avalanche discharge under the condition that the charge-discharge cascade units at all stages are charged and trigger signals are received; the last-stage unit is connected with a load so as to generate target pulse signals at the two ends of the load. According to the Marx generator, the parasitic inductance of the internal circuit of the Marx generator can be effectively reduced, and the quality of the output pulse signal is improved.

Description

Technical Field

[0001] The present application belongs to the field of pulse power technology, and more specifically, relates to a Marx generator and an operating method thereof. Background Art

[0002] High-amplitude, fast-front pulse power technology is widely used in the fields of plasma generation, ultra-wideband positioning, ultra-wideband communication, etc. Avalanche triodes are ultra-high-speed, fast-front semiconductor pulse power devices used in nanosecond (ns) and picosecond (ps) pulse power systems, with a series of excellent characteristics such as high speed and high reliability.

[0003] The main method of using avalanche transistors to generate ultra-high-speed, fast-front high-voltage pulses is the Marx generator. In the prior art, due to the numerous cascade circuits in the Marx generator, the traditional line layout is simple, and the cascade line is long, a large parasitic inductance will be generated on the line when the Marx generator is running, which seriously affects the quality of the output pulse signal.

[0004] Therefore, how to reduce the parasitic inductance of the internal circuit of the Marx generator and improve the quality of the output pulse signal has become a technical problem that needs to be solved urgently in the industry. Summary of the invention

[0005] In view of the defects of the prior art, the purpose of this application is to reduce the parasitic inductance of the internal circuit of the Marx generator and improve the quality of the output pulse signal. It aims to solve the problem in the prior art that the parasitic inductance generated on the circuit when the Marx generator is running is very large, which seriously affects the quality of the output pulse signal.

[0006] To achieve the above objectives, in a first aspect, the present application provides a Marx generator, comprising:

[0007] Double-sided PCB board and N-stage charge and discharge cascade units connected in sequence;

[0008] In the N-stage charge-discharge cascade unit, each first unit with an odd cascade sequence is sequentially arranged on one side of the double-sided PCB board, and each second unit with an even cascade sequence is sequentially arranged on the other side of the double-sided PCB board; each first unit and its adjacent second unit are electrically connected through a preset through hole in the double-sided PCB board, wherein the value range of N is 4 to 10;

[0009] The first-level unit in the N-level charge-discharge cascade unit is used to drive the generator to perform avalanche discharge when the charge-discharge cascade units at each level complete charging and receive a trigger signal; the last-level unit is used to connect the load to generate a target pulse signal at both ends of the load.

[0010] Optionally, each level of the charge-discharge cascade unit includes a plurality of avalanche triode modules connected in sequence, the last avalanche triode module among the plurality of avalanche triode modules serves as a signal input side, and the first avalanche triode module serves as a signal output side;

[0011] The avalanche transistor module includes an avalanche transistor and a resistor connected in parallel at both ends of the avalanche transistor.

[0012] Optionally, each level of the charge-discharge cascade unit further includes a first capacitor and a first isolation resistor; one end of the first isolation resistor in each level of the charge-discharge cascade unit is connected in common as a DC power supply input end; the other end of the first isolation resistor in each level of the charge-discharge cascade unit is connected to one end of each first capacitor, and connected to each last avalanche transistor module;

[0013] Except for the last level unit, the other end of the first capacitor in each other level of the charge and discharge cascade unit is connected to the first avalanche transistor module of the next level of the charge and discharge cascade unit; the other end of the first capacitor in the last level unit is connected to the load.

[0014] Optionally, in addition to the first-level unit, each other level of the charging and discharging cascade unit also includes a second isolation resistor; one end of the second isolation resistor of each level is connected to the respective first avalanche transistor module, and the other end of the second isolation resistor of each level is connected to the output end of the first avalanche transistor module in the first-level unit and grounded.

[0015] Optionally, the generator further includes a trigger signal processing unit, which is used to receive an external square wave signal when the generator completes charging, and convert the external square wave signal into a narrow pulse signal and transmit it to the first-stage unit; the trigger signal is the narrow pulse signal.

[0016] Optionally, the trigger signal processing unit includes a second capacitor and a resistor;

[0017] One end of the second capacitor is used to receive the external square wave signal; the other end of the second capacitor, one end of the resistor and the base of the avalanche transistor in the first avalanche transistor module are connected in common, and the other end of the resistor is connected to the emitter of the avalanche transistor in the first avalanche transistor module and grounded.

[0018] Optionally, the generator includes four-stage charge-discharge cascade units, and each stage of the charge-discharge cascade units includes four avalanche triode modules.

[0019] Optionally, one side and the other side of the double-sided PCB board are both provided with a DC power input terminal and a ground terminal; the DC power input terminal and the ground terminal on one side of the double-sided PCB board are arranged along a first direction; the DC power input terminal and the ground terminal on the other side of the double-sided PCB board are arranged along a second direction; the first direction is opposite to the second direction.

[0020] Optionally, the avalanche transistor includes a FMMT415 series transistor, a FMMT417 series transistor or a C1815 series transistor.

[0021] In a second aspect, the present application further provides an operating method for a Marx generator applied to any of the aforementioned methods, comprising:

[0022] Charging the charge-discharge cascade units of each level cascaded on the double-sided PCB board;

[0023] When the charging and discharging cascade units of each stage complete charging and the first stage unit in the N stages of charging and discharging cascade units receives a trigger signal, driving the charging and discharging cascade units of each stage to discharge in sequence;

[0024] A target pulse signal is generated at both ends of a load connected to the last-stage unit in the N-stage charge-discharge cascade unit.

[0025] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0026] The present application provides a Marx generator and an operating method thereof. The Marx generator includes a double-sided PCB board and N-stage charge-discharge cascade units connected in sequence. By arranging the N-stage charge-discharge cascade units in sequence on both sides of the double-sided PCB board in an interlaced manner according to a cascade odd-even order, and using preset through holes in the double-sided PCB board for electrical connection, the line length between the charge-discharge cascade units can be greatly shortened, the parasitic inductance of the internal line of the Marx generator can be effectively reduced, and a pulse output with a higher amplitude and a shorter rise time can be generated, thereby greatly improving the quality of the pulse signal output by the Marx generator. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a Marx generator provided by the present application;

[0028] Figure 2 This is one of the internal circuit structure diagrams of the Marx generator provided by the present application;

[0029] Figure 3 This is the second schematic diagram of the internal circuit structure of the Marx generator provided by the present application;

[0030] Figure 4 1 is a graph showing the comparison of the output pulse signals of the Marx generator provided in the embodiment of the present application and the traditional Marx generator;

[0031] Figure 5 1 is a schematic diagram comparing simulation results of output pulse signals of the Marx generator provided in the embodiment of the present application and the traditional Marx generator;

[0032] Figure 6 It is a flow chart of the operation method of the Marx generator provided in the embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] The terms "first" and "second" in the specification and claims herein are used to distinguish different objects rather than to describe a specific order of the objects. For example, the first unit and the second unit are used to distinguish different charge-discharge cascade units rather than to describe a specific order of the charge-discharge cascade units; for another example, the first capacitor and the second capacitor are used to distinguish different capacitive devices rather than to describe a specific order of the capacitive devices.

[0035] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0036] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more than two. For example, “plurality of avalanche transistors” means two or more than two avalanche transistors.

[0037] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0038] Figure 1 Schematic diagram of the structure of the Marx generator provided by the present application. Figure 1 As shown, the Marx generator includes:

[0039] A double-sided PCB board 1 and N-stage charge-discharge cascade units 2 connected in sequence;

[0040] In the N-stage charge-discharge cascade unit 2, each first unit 21 with an odd cascade sequence is sequentially arranged on one side of the double-sided PCB board 1, and each second unit 22 with an even cascade sequence is sequentially arranged on the other side of the double-sided PCB board 1; each first unit 21 and its adjacent second unit 22 are electrically connected through a through hole 11 preset in the double-sided PCB board 1, wherein the value range of N is 4 to 10;

[0041] The first-stage unit in the N-stage charge-discharge cascade unit 2 is used to drive the generator to perform avalanche discharge when each stage of the charge-discharge cascade unit 2 completes charging and receives a trigger signal; the last-stage unit is used to connect the load to generate a target pulse signal at both ends of the load.

[0042] Specifically, the charge-discharge cascade unit described in the embodiment of the present application is a circuit unit composed of devices such as an avalanche transistor cascade circuit, a charging capacitor, and a resistor. It is a core circuit module of a Marx generator and is used for energy storage and pulse discharge.

[0043] It can be understood that the N-level charge-discharge cascade unit includes a first-level unit, a second-level unit, ..., an N-th-level unit, the first-level unit is the first charge-discharge cascade unit to be cascaded, the last-level unit is the last charge-discharge cascade unit to be cascaded, and so on. Wherein, the value range of N is 4 to 10. That is to say, in the embodiment of the present application, the Marx generator may include a 4-level charge-discharge cascade unit, or a 5-level charge-discharge cascade unit, ..., or a 10-level charge-discharge cascade unit.

[0044] The target pulse signal described in the embodiment of the present application refers to a pulse signal generated on the load connected to the last unit after each level of charge-discharge cascade unit discharges one by one to form an avalanche discharge. In the embodiment of the present application, the target pulse signal is a pulse output with a higher amplitude and a shorter rise time.

[0045] It should be noted that the avalanche transistor is a specially designed semiconductor device that can withstand high voltage without breakdown under specific working conditions. The design of this transistor allows avalanche breakdown to occur at the PN junction, that is, under the action of a high electric field, carriers (electrons and holes) collide in the lattice to produce more electron-hole pairs, thereby forming a current multiplication effect.

[0046] Based on the content of the above embodiment, as an optional embodiment, the avalanche transistor includes a transistor of the FMMT415 series, a transistor of the FMMT417 series or a transistor of the C1815 series.

[0047] The Marx generator of the embodiment of the present application can be adapted to a variety of different types of avalanche transistors to meet the needs of different application scenarios, improve the flexibility of circuit manufacturing and circuit performance, improve the reliability and stability of the system, and reduce costs and power consumption.

[0048] In an embodiment of the present application, the Marx generator is mainly composed of a double-sided printed circuit board (PCB) and N-level charge-discharge cascade units connected in sequence, and each level of charge-discharge cascade units is arranged on the double-sided PCB board. Among them, according to the cascade sequence, the N-level charge-discharge cascade units are divided into two types of units, specifically including a first unit with an odd cascade sequence and a second unit with an even cascade sequence. For example, in a 4-level charge-discharge cascade unit, the first and third level units belong to the first unit, and the second and fourth level units belong to the second unit.

[0049] Wherein, both sides of the double-sided PCB board can be used to arrange the conductive copper layer and install the electronic devices. This design can make the layout of the Marx generator circuit more compact, help to improve the density and complexity of the circuit, and reduce the size of the circuit board. Specifically, each first unit is arranged in sequence on one side of the double-sided PCB board, and each second unit with an even number of cascade sequences is arranged in sequence on the other side of the double-sided PCB board.

[0050] In the embodiments of the present application, electrical connections can be established between the two layers by utilizing through holes in the double-sided PCB board, which are small holes filled or coated with metal tin, which allow the circuits of the top layer and the bottom layer to be connected to each other. In this way, each first unit and its adjacently connected second unit can be electrically connected through the preset through holes in the double-sided PCB board.

[0051] Further, in an embodiment of the present application, the first-stage unit in the N-stage charge-discharge cascade unit can receive a trigger signal transmitted from the outside when each stage of the charge-discharge cascade unit completes charging, and starts to drive the Marx generator to perform avalanche discharge when receiving the trigger signal. Specifically, the first-stage unit first performs an overvoltage conduction of the internal transistor circuit to discharge, thereby triggering the second-stage unit to discharge, and so on, until the last-stage unit connected to the load is triggered to discharge, and finally generates a target pulse signal at both ends of the load.

[0052] The Marx generator of the embodiment of the present application includes a double-sided PCB board and N-stage charge-discharge cascade units connected in sequence. By arranging the N-stage charge-discharge cascade units in sequence on both sides of the double-sided PCB board in an interlaced manner according to the cascade odd-even order, and using preset through holes in the double-sided PCB board for electrical connection, the line length between the charge-discharge cascade units can be greatly shortened, the parasitic inductance of the internal circuit of the Marx generator can be effectively reduced, and a pulse output with a higher amplitude and a shorter rise time is generated, which greatly improves the quality of the pulse signal output by the Marx generator.

[0053] Figure 2 This is one of the internal circuit structure diagrams of the Marx generator provided by the present application. Figure 2 As shown, as an optional embodiment, each stage of the charge-discharge cascade unit 2 includes a plurality of avalanche triode modules 201 connected in sequence, the last avalanche triode module 201 of the plurality of avalanche triode modules 201 serves as a signal input side, and the first avalanche triode module 201 serves as a signal output side;

[0054] The avalanche transistor module 201 includes an avalanche transistor and a resistor connected in parallel at both ends of the avalanche transistor.

[0055] Specifically, in the embodiment of the present application, each stage of the charge-discharge cascade unit includes a plurality of avalanche transistor modules connected in cascade in sequence, wherein each avalanche transistor module includes an avalanche transistor Q Ni And a parallel connection in the avalanche transistor Q Ni The resistance R at both ends Ni ; At the same time, the last avalanche triode module among the multiple avalanche triode modules serves as the signal input side, and the first avalanche triode module serves as the signal output side.

[0056] It is understandable that the total number N of charge-discharge cascade units can be an odd number or an even number. When the cascade sequence of the last unit is an odd number, it belongs to the first unit; when the cascade sequence of the last unit is an even number, it belongs to the second unit.

[0057] Specifically, in each charge-discharge cascade unit, the avalanche transistor Q in the first avalanche transistor module N1 The collector of the avalanche transistor Q N2 The emitter of the second avalanche transistor module is connected to the avalanche transistor Q N2 The collector of the avalanche transistor Q N3 The emitter of the penultimate avalanche transistor module is connected to N(i-1) The collector of the last avalanche transistor module is connected to the avalanche transistor Q NiThe emitter of the avalanche transistor is connected; wherein the base of each avalanche transistor is connected to its own emitter.

[0058] In an embodiment of the present application, the number i of avalanche transistor modules in each stage of the charge-discharge cascade unit may range from 4 to 8.

[0059] For cascade circuits, it is necessary to ensure that the DC bias is evenly distributed between the avalanche transistors. If the collector-emitter bias of some transistors is relatively high, these transistors may be turned on prematurely due to overvoltage, resulting in a decrease in the output performance of the pulse source. At the same time, when multiple avalanche transistors are used in series, the voltage distribution on the series devices is uneven and self-breakdown occurs because the off-state impedance and distribution parameters of each device are not exactly the same. Therefore, in actual operation, each avalanche transistor needs to be connected in parallel with a resistor greater than 1MΩ for static voltage balancing.

[0060] In the embodiment of the present application, a resistor R of about 2MΩ can be connected in parallel between the collector and emitter of each avalanche transistor. Ni To achieve the purpose of pressure equalization.

[0061] The Marx generator of the embodiment of the present application forms an avalanche transistor cascade unit by connecting a voltage-dividing resistor in parallel at both ends of the avalanche transistor, which can effectively avoid the risk of self-breakdown caused by uneven voltage division of the avalanche transistor cascade circuit, and at the same time can improve the output performance and stability of the generator circuit.

[0062] Continue to refer to Figure 2 , based on the content of the above embodiment, as an optional embodiment, each level of charge and discharge cascade unit 2 also includes a first capacitor C and a first isolation resistor R; one end of the first isolation resistor R in each level of charge and discharge cascade unit is connected in common as a DC power supply input end; the other end of the first isolation resistor in each level of charge and discharge cascade unit is connected to one end of each first capacitor, and connected to the last avalanche transistor module of each level;

[0063] Except for the last unit, the other end of the first capacitor in each of the other charge-discharge cascade units is connected to the first avalanche transistor module of the next charge-discharge cascade unit; the other end of the first capacitor in the last unit is connected to the load.

[0064] Specifically, in the embodiment of the present application, each charging and discharging cascade unit further includes a first capacitor C and a first isolation resistor R. The first capacitor C includes a capacitor C1 in the first-stage unit, a capacitor C2 in the second-stage unit, ..., a capacitor C in the Nth-stage unit, and a first isolation resistor R. N The first isolation resistor R includes the isolation resistor R in the first level unit c1 , the isolation resistor R in the second-level unit c2, ..., the isolation resistor R in the Nth level unit cN .

[0065] In the embodiment of the present application, one end of the first isolation resistor R in each level of the charge-discharge cascade unit is connected in common as a DC power supply input end, which is used to connect an external DC power supply and input a DC voltage. The other end of the first isolation resistor R in each level of the charge-discharge cascade unit is connected to one end of each first capacitor C, and is connected to the last avalanche transistor module of each level to form a charge-discharge loop.

[0066] In the embodiment of the present application, except for the last level unit, the other end of the first capacitor C in each level of the charge-discharge cascade unit is connected to the first avalanche triode module of the next level of the charge-discharge cascade unit to form an avalanche discharge loop. N The other end of the generator is connected to the load, so as to generate a target pulse signal at both ends of the load when the generator forms an avalanche discharge.

[0067] The Marx generator of the embodiment of the present application can effectively build an avalanche discharge circuit of the generator by introducing a capacitor and connecting it to the first avalanche triode module of its next-level unit, and can limit the charging current during the circuit charging process by introducing an isolation resistor. At the same time, the DC charging source and the potential at both ends of the main capacitor are isolated to improve the stability of the Marx generator circuit.

[0068] Continue to refer to Figure 2 Based on the contents of the above embodiments, as an optional embodiment, in addition to the first-stage unit, each of the other charge-discharge cascade units also includes a second isolation resistor R'; one end of the second isolation resistor of each stage is connected to the respective first avalanche transistor module, and the other end of the second isolation resistor of each stage is connected to the output end of the first avalanche transistor module in the first-stage unit and grounded.

[0069] Specifically, in the embodiment of the present application, in the N-stage charge-discharge cascade unit, except for the first-stage unit, each other stage of the charge-discharge cascade unit further includes a second isolation resistor R', wherein the second isolation resistor R' specifically includes the isolation resistor R' in the second-stage unit. c1 , Isolation resistor R' in the second-level unit c2 , ..., and the isolation resistor R' in the Nth level unit cN .

[0070] In addition, one end of the second isolation resistor R' of each stage is connected to the avalanche transistor Q in the first avalanche transistor module of each stage. N1 The emitter of each second isolation resistor R' is connected, and the other end of each second isolation resistor R' is connected to the avalanche transistor Q of the first avalanche transistor module in the first level unit. 11The emitter of the first avalanche transistor module is connected to the ground, where it can be understood that the avalanche transistor Q 11 The emitter of is the output end of the first avalanche transistor module.

[0071] The Marx generator of the embodiment of the present application can prevent electrostatic discharge from damaging circuit components by introducing a second isolation resistor on the ground side of each level of charging and discharging cascade unit except the first level unit, further improve the stability and reliability of the generator circuit charging process, and protect the circuit safety.

[0072] Continue to refer to Figure 2 Based on the content of the above embodiment, as an optional embodiment, the generator also includes a trigger signal processing unit 3, which is used to receive an external square wave signal when the generator completes charging, and convert the external square wave signal into a narrow pulse signal and transmit it to the first-level unit; the trigger signal is a narrow pulse signal.

[0073] Specifically, in an embodiment of the present application, the Marx generator further includes a trigger signal processing unit, which may specifically adopt a differential circuit, and by performing differential processing on the input square wave signal, the input square wave signal may be effectively converted into a narrow pulse signal.

[0074] Based on the content of the above embodiment, as an optional embodiment, the trigger signal processing unit 3 includes a second capacitor C0 and a resistor R0;

[0075] One end of the second capacitor C0 is used to receive an external square wave signal; the other end of the second capacitor C0, one end of the resistor R0 and the avalanche transistor Q in the first avalanche transistor module 11 The base of the resistor is connected in common, and the other end of the resistor is connected to the avalanche transistor Q in the first avalanche transistor module. 11 The emitter of is connected and grounded.

[0076] Specifically, in the embodiment of the present application, a differential circuit composed of an RC circuit is introduced to process the square wave signal generated by the external trigger. The second capacitor C0 and the resistor R0 are the trigger signal input capacitor and input resistor respectively.

[0077] In an embodiment of the present application, after each level of the charge and discharge cascade units completes charging, an external trigger triggers a square wave signal. The square wave signal is processed by the second capacitor C0 and the resistor R0 to convert it into a narrow pulse signal and transmit it to the first-level unit in the N-level charge and discharge cascade units. By utilizing the overvoltage conduction method, each avalanche transistor in the first-level unit is triggered to turn on one by one to form a discharge loop, and then the charge and discharge cascade units of each level are turned on in turn to form an avalanche discharge until the required high-voltage pulse signal is generated on the load connected to the last-level unit.

[0078] In the embodiments of the present application, by using only one resistor and one capacitor to construct a trigger signal processing unit, it is possible to achieve fast response while also having the advantages of simple structure, clear functions, strong adjustability and low cost.

[0079] The Marx generator of the embodiment of the present application can transform the external rectangular pulse trigger signal into a narrow pulse signal by introducing an RC differential circuit, effectively extract the leading edge or trailing edge of the pulse signal, and can more efficiently trigger and control the conduction of the avalanche transistor in the charge and discharge cascade unit, which is beneficial to further improve the quality of the output pulse signal.

[0080] Figure 3 This is the second schematic diagram of the internal circuit structure of the Marx generator provided by the present application. Figure 3 As shown, as an optional embodiment, the generator includes four charge-discharge cascade units 2, and each charge-discharge cascade unit 2 includes four avalanche transistor modules 201. Among them, the first-level unit and the third-level unit are the first unit 21, the second-level unit and the fourth-level unit are the second unit 22, and the generator also includes a trigger signal processing unit 3.

[0081] It should be noted that in the embodiments of the present application, the more the number of cascaded N-stage charge and discharge cascade units in the Marx generator circuit, and the more the number of cascaded avalanche transistor modules in each charge and discharge cascade unit cascade, the more likely it is that the output voltage of the generator circuit will be saturated, thereby affecting the quality of the output pulse signal; at the same time, it will also bring the risk of high-voltage damage.

[0082] Specifically, in the embodiments of the present application, in order to reliably generate high-quality pulse outputs with higher amplitudes and shorter rise times on the Marx generator, a novel double-sided layout 4×4-stage avalanche triode Marx generator is designed, that is, the generator includes four-stage charge and discharge cascade units, and each stage of the charge and discharge cascade unit includes four avalanche triode modules.

[0083] Different from the traditional single-sided layout, the present application distributes the 4-level charge and discharge cascade units (each level contains 4 avalanche transistor modules) to the front and back sides of the double-sided PCB board, wherein the first-level unit and the third-level unit are placed on the front side, and the second-level unit and the fourth-level unit are placed on the back side. In the N×i-level Marx generator, the collector of the i-th avalanche transistor in each level will be connected to the base of the first avalanche transistor in the next level through the first capacitor. In the traditional single-sided layout, the length of the wire connecting each level is long, and the parasitic inductance is large. In the embodiment of the present application, the through holes connecting the avalanche transistors of each level on the front and back sides pass through the 2mm thick double-sided PCB board, which can greatly reduce the parasitic inductance of the loop.

[0084] Specifically, if Figure 3 As shown, in the embodiment of the present application, in the Marx generator cascade circuit, four avalanche transistor modules are grouped together from top to bottom, with a total of four groups. 11 The base of is connected to the square wave trigger signal from the signal generator through the second capacitor C0 and the resistor R0. 11 The collector of the first-stage unit is connected to the second avalanche transistor Q 12 The emitter and base of the third and fourth transistors are connected in this way. The fourth avalanche transistor Q 14 The collector of c1 Connected to the DC power supply terminal Vcc, and connected to the first capacitor C1 through the through hole and the first avalanche transistor Q of the second-level unit 21 The base and emitter of the second to fourth stages are connected, and the same is true for the second to fourth stages. Each stage is electrically connected through a through hole in turn; the first avalanche transistor Q 21 , Q 31 , Q 41 The emitter of the c1 , R' c2 , R' c3 Ground, the fourth avalanche transistor Q of the last stage unit 44 The collector of is connected to one end of the first capacitor C4, and the first capacitor C4 is connected to the load R L In each avalanche transistor module, a voltage-equalizing resistor R is connected in parallel between the emitter and collector of the avalanche transistor. Ni .

[0085] The working principle of the Marx generator is as follows: During the charging process, the power supply terminal Vcc passes through the first isolation resistor R c1 ~R c3 and the second isolation resistor R' c1 ~R' c3 The first capacitors C1 to C3 are charged through the first isolation resistor R c4 and load R L The capacitor C4 is charged, making the avalanche transistor Q 11 ~Q 44 It works in the critical avalanche region. When the charging is completed, the external trigger signal triggers the avalanche transistor Q 11 Open, Q 12 ~Q 14 Overvoltage turns on, triggering the first capacitor C1 through the avalanche transistor Q 11 ~Q 14 Discharge forming loop C1-Q 14 -Q 13 -Q 12 -Q11 -R' c1 -C1, in R' c1 A negative pulse is generated on the Q 21 The voltage ramp that generates dv / dt on the 21 The two ends exceed a certain withstand voltage value, and then the overvoltage opens, causing C2 to discharge in series with C1, forming a loop C2-Q 24 -Q 23 -Q 22 -Q 21 -C1-Q 14 -Q 13 -Q 12 -Q 11 -R' c2 -C2, in R' c2 A negative pulse is generated on the load, and then the remaining avalanche transistors are turned on in sequence, so that the capacitors C1 to C4 are discharged in series, and finally the load R L A high voltage target pulse signal is generated on the surface to complete a pulse discharge.

[0086] It is understandable that, by analogy, according to the above avalanche discharge principle, it can be extended to the case of N×i-level Marx generator circuits, which will not be elaborated in this application.

[0087] For the traditional single-sided layout, the loops all occur on one side of the circuit board. There are three long connections on the PCB board in the 4×4-level Marx generator circuit, with a length of about 27mm. As shown in Table 1, after the simulation tool Ansys Slwave extracts the paths on the PCB board and imports them into the simulation tool Ansys Q3D simulation, the parasitic inductance of each long connection is obtained to be 18.2621nH, 18.7925nH and 18.2391nH respectively, and the sum of the three is 55.2937nH.

[0088] According to the new double-sided layout 4×4-level Marx generator circuit proposed in the embodiment of the present application, the capacitor connected to the fourth avalanche transistor in each level of the charging and discharging cascade unit is connected to the base of the first avalanche transistor of the next level through a through hole, which can transform the connection of the planar loop with a length of 27 mm into a vertical loop with a thickness of only 2 mm, thereby greatly reducing the parasitic inductance of the line.

[0089] Table 1

[0090]

[0091] Further, in the embodiment of the present application, as shown in Table 1, the parasitic inductances of the three through holes and the shorter, necessary connections are 4.7013nH, 1.7541nH, and 2.8334nH, respectively, and the total is only 9.2888nH. Compared with the above-mentioned traditional single-sided layout, this has an excellent parasitic inductance improvement of 83.20%. The size of the parasitic inductance affects the amplitude, rise time, pulse quality, turn-on stability, etc. of the output pulse. The smaller the parasitic inductance, the larger the final output pulse amplitude and the shorter the rise time.

[0092] Figure 4 FIG. 1 is a schematic diagram comparing the experimental results of the output pulse signals of the Marx generator provided in the embodiment of the present application and the traditional Marx generator, as shown in FIG. Figure 4 As shown, in the embodiment of the present application, after simulation experiment test verification, the Marx generator of the embodiment of the present application can generate an output pulse with an amplitude of 2.50kV and a rise time of 1.93ns; compared with the traditional single-sided layout Marx generator of the same specification, the output pulse amplitude is 1.79kV and the rise time is 4.76ns under the same test conditions. The Marx generator of the embodiment of the present application has increased the pulse amplitude and rise time by 39.7% and 59.5% respectively.

[0093] Figure 5 FIG. 1 is a schematic diagram comparing simulation results of output pulse signals of the Marx generator provided in the embodiment of the present application and the traditional Marx generator, as shown in FIG. Figure 5 As shown, in the simulation results, the output pulse amplitude of the traditional single-sided Marx generator is 2.01 kV, while the output pulse amplitude of the double-sided vertical Marx generator in the embodiment of the present application is 2.36 kV, which is an increase of 17.4%, which is roughly consistent with the above experimental test results.

[0094] The Marx generator of the embodiment of the present application is constructed by utilizing a four-stage charge and discharge cascade unit in which each stage of the charge and discharge cascade unit includes four avalanche transistor modules, and adopts a double-sided circuit layout. It can extract high-amplitude and short rise time high-quality pulse output while ensuring circuit safety and reducing device costs.

[0095] Based on the contents of the above embodiments, as an optional embodiment, one side and the other side of a double-sided PCB board are both provided with a DC power input terminal and a ground terminal; the DC power input terminal and the ground terminal on one side of the double-sided PCB board are arranged along a first direction; the DC power input terminal and the ground terminal on the other side of the double-sided PCB board are arranged along a second direction; the first direction is opposite to the second direction.

[0096] Specifically, in the embodiment of the present application, because the emitter of the first avalanche transistor in each level unit needs to pass through the second isolation resistor R' c1 ~R' c(N-1) Ground (except for the avalanche transistor Q in the first stage unit 11 The emitter of the transistor is directly grounded), and the collector of the fourth avalanche transistor in each unit level must pass through the first isolation resistor R c1 ~R cN Connecting Vcc, i.e. the DC power input terminal of the power supply, introducing a through hole on the double-sided PCB board will inevitably cause the adjacent two-stage avalanche transistor cascade circuit to be turned upside down.

[0097] Therefore, in the embodiment of the present application, Vcc terminals and ground terminals are designed on the front and back sides of the double-sided PCB board respectively. In order to prevent the PCB board from being broken down by high voltage (such as the high voltage of the four avalanche transistor module circuits can reach 1300V), the Vcc terminals and ground terminals on the front and back sides are completely staggered, that is, the Vcc terminals and ground terminals on one side of the double-sided PCB board are arranged along a first direction, and the Vcc terminals and ground terminals on the other side of the double-sided PCB board are arranged along an opposite second direction. In addition, the Vcc terminals on each side can be connected to a DC power supply through two power lines that are divided into two.

[0098] The Marx generator of the embodiment of the present application adopts a double-sided layout mode of the Marx generator circuit on the double-sided PCB board. By adopting a double-sided design and staggered arrangement of the DC power input terminal and the ground terminal, the influence of high voltage on the operation of the generator circuit can be effectively prevented, and the risk of high voltage breaking through the PCB circuit board and burning out electronic devices can be avoided, thereby further improving the stability and reliability of the operation of the Marx generator.

[0099] The operating method of the Marx generator provided by the present invention is described below. The operating method of the Marx generator described below and the Marx generator described above can be referred to each other.

[0100] Figure 6 is a flow chart of the operation method of the Marx generator provided in the embodiment of the present application, which can be applied to any of the aforementioned Marx generators, such as Figure 6 As shown, the method includes:

[0101] Step S1, charging each level of the charge-discharge cascade units cascaded on the double-sided PCB board;

[0102] Step S2, when each level of the charge-discharge cascade unit completes charging and the first level unit in the N levels of the charge-discharge cascade unit receives a trigger signal, the charge-discharge cascade units at each level are sequentially driven to discharge;

[0103] Step S3, generating a target pulse signal at both ends of a load connected to the last-stage unit in the N-stage charge-discharge cascade unit.

[0104] It should be understood that the above-mentioned device is used to execute the method in the above-mentioned embodiment. The implementation principle and technical effect of the corresponding program module in the device are similar to those described in the above-mentioned method. The working process of the device can refer to the corresponding process in the above-mentioned method, which will not be repeated here.

[0105] The operating method of the Marx generator of the embodiment of the present application comprises a double-sided PCB board and N-stage charge-discharge cascade units connected in sequence. By arranging the N-stage charge-discharge cascade units in sequence on both sides of the double-sided PCB board in an interlaced manner according to the cascade odd-even order, and using preset through holes in the double-sided PCB board for electrical connection, the line length between the charge-discharge cascade units can be greatly shortened, the parasitic inductance of the internal line of the Marx generator can be effectively reduced, and a pulse output with a higher amplitude and a shorter rise time can be generated, thereby greatly improving the quality of the pulse signal output by the Marx generator.

[0106] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0107] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. Among them, "fixed connection" means that the two are connected to each other and the relative position relationship remains unchanged after the connection. "Rotational connection" means that the two are connected to each other and can rotate relative to each other after the connection. "Sliding connection" means that the two are connected to each other and can slide relative to each other after the connection.

[0108] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A Marx generator, characterized in that: include: Double-sided PCB board and N-stage charge and discharge cascade units connected in sequence; In the N-stage charge-discharge cascade unit, each first unit with an odd cascade sequence is sequentially arranged on one side of the double-sided PCB board, and each second unit with an even cascade sequence is sequentially arranged on the other side of the double-sided PCB board; each first unit and its adjacent second unit are electrically connected through a preset through hole in the double-sided PCB board, wherein the value range of N is 4 to 10; The first-level unit in the N-level charge-discharge cascade unit is used to drive the generator to perform avalanche discharge when the charge-discharge cascade units at each level complete charging and receive a trigger signal; the last-level unit is used to connect the load to generate a target pulse signal at both ends of the load.

2. The Marx generator according to claim 1, characterized in that: Each level of the charge-discharge cascade unit comprises a plurality of avalanche triode modules connected in sequence, wherein the last avalanche triode module among the plurality of avalanche triode modules serves as a signal input side, and the first avalanche triode module serves as a signal output side; The avalanche transistor module includes an avalanche transistor and a resistor connected in parallel at both ends of the avalanche transistor.

3. The Marx generator according to claim 2, characterized in that: Each level of the charge-discharge cascade unit further includes a first capacitor and a first isolation resistor; one end of the first isolation resistor in each level of the charge-discharge cascade unit is connected in common as a DC power supply input end; the other end of the first isolation resistor in each level of the charge-discharge cascade unit is connected to one end of each first capacitor, and connected to the last avalanche transistor module of each level; Except for the last level unit, the other end of the first capacitor in each other level of the charge and discharge cascade unit is connected to the first avalanche transistor module of the next level of the charge and discharge cascade unit; the other end of the first capacitor in the last level unit is connected to the load.

4. The Marx generator according to claim 3, characterized in that: In addition to the first-level unit, each other level of the charging and discharging cascade unit also includes a second isolation resistor; one end of the second isolation resistor of each level is connected to the respective first avalanche transistor module, and the other end of the second isolation resistor of each level is connected to the output end of the first avalanche transistor module in the first-level unit and grounded.

5. The Marx generator according to claim 2, characterized in that: The generator further includes a trigger signal processing unit, which is used to receive an external square wave signal when the generator is fully charged, and convert the external square wave signal into a narrow pulse signal and transmit it to the first stage unit; The trigger signal is the narrow pulse signal.

6. The Marx generator according to claim 5, characterized in that: The trigger signal processing unit includes a second capacitor and a resistor; One end of the second capacitor is used to receive the external square wave signal; the other end of the second capacitor, one end of the resistor and the base of the avalanche transistor in the first avalanche transistor module are connected in common, and the other end of the resistor is connected to the emitter of the avalanche transistor in the first avalanche transistor module and grounded.

7. The Marx generator according to claim 6, characterized in that: The generator comprises four-stage charge-discharge cascade units, and each stage of the charge-discharge cascade units comprises four avalanche triode modules.

8. The Marx generator according to any one of claims 1 to 7, characterized in that: One side and the other side of the double-sided PCB board are both provided with a DC power input terminal and a ground terminal; the DC power input terminal and the ground terminal on one side of the double-sided PCB board are arranged along a first direction; the DC power input terminal and the ground terminal on the other side of the double-sided PCB board are arranged along a second direction; the first direction is opposite to the second direction.

9. The Marx generator according to any one of claims 1 to 7, characterized in that: The avalanche transistor includes a transistor of the FMMT415 series, a transistor of the FMMT417 series or a transistor of the C1815 series.

10. An operating method for a Marx generator according to any one of claims 1 to 9, characterized in that: include: Charging the charge-discharge cascade units of each level cascaded on the double-sided PCB board; When the charging and discharging cascade units of each stage complete charging and the first stage unit in the N stages of charging and discharging cascade units receives a trigger signal, driving the charging and discharging cascade units of each stage to discharge in sequence; A target pulse signal is generated at both ends of a load connected to the last-stage unit in the N-stage charge-discharge cascade unit.

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