Marx generator and method of operation thereof

Abstract

The application belongs to the technical field of pulse power, and specifically discloses a Marx generator and a running method thereof. The Marx generator comprises a double-sided PCB board and N-stage charge-discharge cascade units connected in sequence. In the N-stage charge-discharge cascade units, each first unit with an odd cascade order is arranged on one side of the double-sided PCB board in sequence, and each second unit with an even cascade order is arranged on the other side of the double-sided PCB board in sequence. Each first unit and its adjacent second unit are electrically connected through a preset through hole in the double-sided PCB board. The first unit in the N-stage charge-discharge cascade units drives the generator to perform avalanche discharge when the charge of each stage of the charge-discharge cascade units is completed and a trigger signal is received. The last unit is connected to a load to generate a target pulse signal across the load. Through the application, the parasitic inductance of the internal circuit of the Marx generator can be effectively reduced, and the quality of the output pulse signal can be improved.

Description

Technical Field

[0001] This application belongs to the field of pulse power technology, and more specifically, relates to a Marx generator and its operating method. Background Technology

[0002] High-amplitude, fast-leading-edge pulsed power technology is widely used in plasma generation, ultra-wideband positioning, and ultra-wideband communication. Avalanche transistors, as ultra-high-speed, fast-leading-edge semiconductor pulsed power devices used in nanosecond (ns) and picosecond (ps) pulsed power systems, possess a series of excellent characteristics such as high speed and high reliability.

[0003] The main method for generating ultra-high-speed, fast-leading-edge high-voltage pulses using avalanche transistors is the Marx generator. In existing technologies, due to the numerous cascaded circuits in Marx generators, the traditional wiring layout is simple but the cascaded lines are lengthy, resulting in significant parasitic inductance on the lines during operation. This severely affects the quality of the output pulse signal.

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

[0005] In view of the shortcomings 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 that the parasitic inductance generated on the circuit of the Marx generator during operation is very large, which seriously affects the quality of the output pulse signal.

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

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

[0008] In the N-level charge-discharge cascaded unit, each first unit with an odd cascade order is arranged sequentially on one side of the double-sided PCB board, and each second unit with an even cascade order is arranged sequentially on the other side of the double-sided PCB board; each first unit and its adjacent second unit are electrically connected through a pre-set through hole in the double-sided PCB board, wherein the value of N ranges from 4 to 10.

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

[0010] Optionally, each stage of the charge-discharge cascade unit includes multiple avalanche transistor modules connected in sequence, wherein the last avalanche transistor module among the multiple avalanche transistor modules serves as the signal input side and the first avalanche transistor module serves as the signal output side.

[0011] The avalanche transistor module includes an avalanche transistor and a resistor connected in parallel across the avalanche transistor.

[0012] Optionally, each of the charge-discharge cascade units further includes a first capacitor and a first isolation resistor; one end of the first isolation resistor in each of the charge-discharge cascade units is connected together as a DC power input terminal; the other end of the first isolation resistor in each of the charge-discharge cascade units is connected to one end of its respective first capacitor and connected to its respective last avalanche transistor module.

[0013] Except for the last stage 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 stage charge-discharge cascade unit; the other end of the first capacitor in the last stage unit is connected to the load.

[0014] Optionally, in addition to the first stage unit, each of the other charge-discharge cascade units further includes a second isolation resistor; one end of the second isolation resistor in each stage is connected to its respective first avalanche transistor module, and the other end of the second isolation resistor in each stage is connected to the output terminal of the first avalanche transistor module in the first stage 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 has completed 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 together, 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 a four-stage charge-discharge cascade unit, and each stage of the charge-discharge cascade unit includes four avalanche transistor modules.

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

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

[0021] Secondly, this application also provides a method for operating a Marx generator as described above, comprising:

[0022] The cascaded charge-discharge units connected in each stage on the double-sided PCB are charged.

[0023] When each of the charging and discharging cascaded units completes charging and the first unit in the N-stage charging and discharging cascaded unit receives a trigger signal, each of the charging and discharging cascaded units is driven to discharge sequentially.

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

[0025] Overall, the technical solutions conceived in this application have the following beneficial effects compared with the prior art:

[0026] This application provides a Marx generator and its operating method. 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 an alternating order on both sides of the double-sided PCB board and electrically connecting them using pre-set through holes in the double-sided PCB board, the line length between the charge-discharge cascade units can be greatly shortened, effectively reducing the parasitic inductance of the internal circuitry of the Marx generator, generating pulse outputs with higher amplitude and shorter rise time, and greatly improving the quality of the pulse signal output by the Marx generator. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the Marx generator provided in this application.

[0028] Figure 2 This is one of the schematic diagrams of the internal circuit structure of the Marx generator provided in this application;

[0029] Figure 3 This is the second schematic diagram of the internal circuit structure of the Marx generator provided in this application.

[0030] Figure 4 This is a comparative experimental result diagram of the output pulse signals of the Marx generator provided in the embodiments of this application and a conventional Marx generator;

[0031] Figure 5 This is a schematic diagram comparing the simulation results of the output pulse signals of the Marx generator provided in this embodiment with those of a conventional Marx generator;

[0032] Figure 6 This is a flowchart illustrating the operation method of the Marx generator provided in the embodiments of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] The terms "first" and "second," etc., used in the specification and claims herein are used to distinguish different objects, not to describe a specific order of objects. For example, "first unit" and "second unit" are used to distinguish different charge-discharge cascade units, not to describe a specific order of charge-discharge cascade units; similarly, "first capacitor" and "second capacitor" are used to distinguish different capacitor components, not to describe a specific order of capacitor components.

[0035] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0036] In the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more, for example, multiple avalanche transistors means two or more avalanche transistors, etc.

[0037] The embodiments of this application are described below with reference to the accompanying drawings.

[0038] Figure 1 This is a schematic diagram of the Marx generator provided in this application, as shown below. Figure 1 As shown, the Marx generator includes:

[0039] Double-sided PCB board 1 and N-stage charge-discharge cascaded units 2 connected in sequence;

[0040] In the N-level charge-discharge cascade unit 2, each first unit 21 with an odd cascade order is arranged sequentially on one side of the double-sided PCB board 1, and each second unit 22 with an even cascade order is arranged sequentially 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 pre-set through hole 11 in the double-sided PCB board 1, wherein the value of N ranges from 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 has completed charging and received 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 this application embodiment is a circuit unit composed of avalanche transistor cascade circuit, charging capacitor, resistor and other devices. It belongs to the core circuit module of the Marx generator and is used for energy storage and pulse discharge.

[0043] It is understood that an N-stage charge-discharge cascade unit includes a first-stage unit, a second-stage unit, ..., an Nth-stage unit, where the first-stage unit is the first charge-discharge cascade unit to be cascaded, the last-stage unit is the last charge-discharge cascade unit to be cascaded, and so on. The value of N ranges from 4 to 10. That is, in the embodiments of this application, the Marx generator may include 4-stage charge-discharge cascade units, or 5-stage charge-discharge cascade units, ..., or 10-stage charge-discharge cascade units.

[0044] The target pulse signal described in the embodiments of this application refers to the pulse signal generated on the load connected to the last stage unit after each stage of the cascaded charge-discharge units has discharged sequentially to form an avalanche discharge. In the embodiments of this application, the target pulse signal is characterized by a pulse output with a higher amplitude and a shorter rise time.

[0045] It should be noted that an avalanche transistor is a specially designed semiconductor device that can withstand high voltages under specific operating conditions without breaking down. This type of transistor is designed to allow avalanche breakdown at the PN junction, meaning that under a high electric field, charge carriers (electrons and holes) collide in the crystal lattice, generating more electron-hole pairs, thus creating a current multiplication effect.

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

[0047] The Marx generator of this application embodiment can be adapted to various avalanche transistors to meet the needs of different application scenarios, improve the flexibility of circuit fabrication and circuit performance, enhance the reliability and stability of the system, and reduce cost and power consumption.

[0048] In the embodiments of this application, the Marx generator mainly consists of a double-sided printed circuit board (PCB) and N-stage charge-discharge cascade units connected in sequence. Each stage of the charge-discharge cascade unit is arranged on the double-sided PCB. The N-stage charge-discharge cascade unit is divided into two types of units according to the cascade order: a first unit with an odd cascade order and a second unit with an even cascade order. For example, in a 4-stage charge-discharge cascade unit, the first and third stages belong to the first stage, while the second and fourth stages belong to the second stage.

[0049] In this design, both sides of the double-sided PCB can be used to arrange conductive copper layers and mount electronic components. This design allows for a more compact layout of the Marx generator circuit, helping to increase circuit density and complexity while reducing the size of the circuit board. Specifically, each first unit is arranged sequentially on one side of the double-sided PCB, and each second unit with an even-numbered cascade sequence is arranged sequentially on the other side of the double-sided PCB.

[0050] In embodiments of this application, electrical connections can be established between two layers using through-holes in a double-sided PCB. These through-holes are small holes filled or coated with tin, allowing the circuitry of the top and bottom layers to be interconnected. Thus, each first unit can be electrically connected to its adjacent second unit through pre-defined through-holes in the double-sided PCB.

[0051] Furthermore, in the embodiments of this application, the first-stage unit in the N-stage charge-discharge cascade unit can receive an externally transmitted trigger signal when each stage of the charge-discharge cascade unit completes charging. Upon receiving the trigger signal, it begins to drive the Marx generator to perform avalanche discharge. Specifically, the first-stage unit first performs overvoltage conduction of its internal transistor circuit, thereby discharging, which in turn triggers the second-stage unit to discharge, and so on, until the last-stage unit connected to the load is triggered to discharge, ultimately generating a target pulse signal at both ends of the load.

[0052] The Marx generator of this application embodiment 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 an alternating order on both sides of the double-sided PCB board and connecting them electrically using pre-set through holes in the double-sided PCB board, the line length between the charge-discharge cascade units can be greatly shortened, effectively reducing the parasitic inductance of the internal circuit of the Marx generator, generating pulse output with higher amplitude and shorter rise time, and greatly improving the quality of the pulse signal output by the Marx generator.

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

[0054] The avalanche transistor module 201 includes an avalanche transistor and a resistor connected in parallel across the avalanche transistor.

[0055] Specifically, in the embodiments of this application, each charge-discharge cascade unit includes multiple avalanche transistor modules connected in sequence, wherein each avalanche transistor module includes an avalanche transistor Q. Ni and a parallel connection to the avalanche transistor Q Ni The resistance R at both ends Ni Meanwhile, the last avalanche transistor module in the multiple avalanche transistor modules serves as the signal input side, and the first avalanche transistor module serves as the signal output side.

[0056] Understandably, the total number of stages N in the charge-discharge cascade unit can be either odd or even. When the cascade order of the last stage unit is odd, it belongs to the first stage; when the cascade order of the last stage unit is even, it belongs to the second stage.

[0057] Specifically, in each stage of the charge-discharge cascade unit, the avalanche transistor Q in the first avalanche transistor module N1 The collector of the second avalanche transistor module and the avalanche transistor Q N2 The emitter connection is made to the second avalanche transistor module's avalanche transistor Q. N2 The collector of the third avalanche transistor module and the avalanche transistor Q N3 The emitter connection is repeated, and so on, with the second-to-last avalanche transistor module's avalanche transistor Q... N(i-1) The collector of the avalanche transistor and the avalanche transistor Q of the last avalanche transistor module NiThe emitter is connected; wherein, the base of each avalanche transistor is connected to its respective emitter.

[0058] In the embodiments of this application, the number i of avalanche transistor modules in each charge-discharge cascade unit can range from 4 to 8.

[0059] For cascaded circuits, it is crucial to ensure that the DC bias is evenly distributed across all avalanche transistors. If some transistors have relatively high collector-emitter biases, they may conduct prematurely due to overvoltage, leading to a degraded pulse source output performance. Furthermore, when multiple avalanche transistors are connected in series, the uneven voltage distribution across the series components due to differences in off-state impedance and distributed parameters can cause self-breakdown. Therefore, in practice, each avalanche transistor requires a resistor greater than 1MΩ connected in parallel for static voltage equalization.

[0060] In the embodiments of this application, a resistor R of approximately 2MΩ can be connected in parallel between the collector and emitter of each avalanche transistor. Ni This is to achieve the purpose of equalizing pressure.

[0061] The Marx generator in this application embodiment forms an avalanche transistor cascade unit by connecting a voltage divider resistor in parallel across the avalanche transistor. This effectively avoids the risk of self-breakdown caused by uneven voltage division in the avalanche transistor cascade circuit, and also improves the output performance and stability of the generator circuit.

[0062] Continue to refer to Figure 2 Based on the above embodiments, as an optional embodiment, each charge-discharge cascade unit 2 further includes a first capacitor C and a first isolation resistor R; one end of the first isolation resistor R in each charge-discharge cascade unit is connected together as a DC power input terminal; the other end of the first isolation resistor in each charge-discharge cascade unit is connected to one end of its respective first capacitor and connected to its respective last avalanche transistor module.

[0063] Except for the last stage 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 stage charge-discharge cascade unit; the other end of the first capacitor in the last stage unit is connected to the load.

[0064] Specifically, in the embodiments of this application, each charge-discharge cascade unit further includes a first capacitor C and a first isolation resistor R. The first capacitor C includes capacitor C1 in the first-stage unit, capacitor C2 in the second-stage unit, ..., capacitor C in the Nth-stage unit. N The first isolation resistor R includes the isolation resistor R in the first-stage unit. c1 The isolation resistor R in the second-stage unit c2The isolation resistor R in the Nth level unit... cN .

[0065] In the embodiments of this application, one end of the first isolation resistor R in each of the charging and discharging cascade units is shared and used as a DC power input terminal to connect to an external DC power supply and input DC voltage. The other end of the first isolation resistor R in each of the charging and discharging cascade units is connected to one end of its respective first capacitor C, and then connected to its respective last avalanche transistor module to form a charging and discharging circuit.

[0066] In the embodiments of this application, except for the last stage unit, the other end of the first capacitor C in each of the other charge-discharge cascade units is connected to the first avalanche transistor module of the next stage charge-discharge cascade unit to form an avalanche discharge circuit. The first capacitor C in the last stage unit... N The other end is connected to the load and is used to generate a target pulse signal at both ends of the load when the generator forms an avalanche discharge.

[0067] The Marx generator in this embodiment of the application can effectively build an avalanche discharge circuit by introducing a capacitor and connecting it to the first avalanche transistor module of its next-level unit. By introducing an isolation resistor, the charging current is limited during the circuit charging process. At the same time, the potentials at both ends of the DC charging source and the main capacitor are isolated, thereby improving the stability of the Marx generator circuit.

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

[0069] Specifically, in the embodiments of this application, in the N-stage charge-discharge cascade unit, in addition to the first-stage unit, each other 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 The isolation resistor R' in the second-stage unit c2 ... and the isolation resistor R' in the Nth level unit. cN .

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

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

[0072] Continue to refer to Figure 2 Based on the above embodiments, as an optional embodiment, the generator further includes a trigger signal processing unit 3. The trigger signal processing unit 3 is used to receive an external square wave signal when the generator has completed 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 a narrow pulse signal.

[0073] Specifically, in the embodiments of this application, the Marx generator further includes a trigger signal processing unit, which may be a differentiating circuit. By differentiating the input square wave signal, it can be effectively converted into a narrow pulse signal.

[0074] Based on the above embodiments, 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 is connected and grounded.

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

[0077] In the embodiments of this application, after each stage of the charge-discharge cascade unit completes charging, an external trigger triggers a square wave signal. Through the processing of the square wave signal by the second capacitor C0 and resistor R0, it can be converted into a narrow pulse signal and transmitted to the first stage unit in the N-stage charge-discharge cascade unit. Using the overvoltage conduction method, each avalanche transistor in the first stage unit is triggered to conduct one by one, forming a discharge circuit. Then, each stage of the charge-discharge cascade unit is turned on in sequence to form an avalanche discharge until the required high-voltage pulse signal is generated on the load connected to the last stage unit.

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

[0079] The Marx generator in this embodiment of the application, by introducing an RC differentiating circuit, can transform an external rectangular pulse trigger signal into a narrow pulse signal, effectively extracting the leading edge or trailing edge of the pulse signal. This allows for more efficient triggering and control of the avalanche transistor in the charge-discharge cascade unit, which is beneficial for further improving 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 in this application, as shown below. Figure 3 As shown, in one optional embodiment, the generator includes a four-stage charge-discharge cascade unit 2, each stage of which includes four avalanche transistor modules 201. The first and third stages are designated as first units 21, and the second and fourth stages are designated as second units 22. The generator also includes a trigger signal processing unit 3.

[0081] It should be noted that, in the embodiments of this application, the more units cascaded in the N-stage charge-discharge cascade unit of the Marx generator circuit, and the more avalanche transistor modules cascaded in each charge-discharge cascade unit, the more the generator circuit output voltage will eventually saturate, 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 this application, in order to reliably generate high-quality pulse output with higher amplitude and shorter rise time on the Marx generator, a novel double-sided layout 4×4 stage avalanche triode Marx generator is designed, that is, the generator includes four stages of charge-discharge cascaded units, and each stage of charge-discharge cascaded unit includes four avalanche triode modules.

[0083] Unlike traditional single-sided layouts, this application distributes four cascaded charge / discharge units (each containing four avalanche transistor modules) across both sides of a double-sided PCB board. The first and third stage units are placed on the front, while the second and fourth stage units are placed on the back. In an N×i-stage Marx generator, the collector of the i-th avalanche transistor in each stage is connected to the base of the first avalanche transistor in the next stage via a first capacitor. In traditional single-sided layouts, the connecting wires between stages are quite long, resulting in significant parasitic inductance. In this embodiment, the vias connecting the avalanche transistors on both sides penetrate the 2mm thick double-sided PCB board, greatly reducing the parasitic inductance of the circuit.

[0084] Specifically, such as Figure 3 As shown in the embodiment of this application, in the Marx generator cascade circuit, four avalanche transistor modules are arranged in a group from top to bottom, for a total of four groups. The first avalanche transistor Q in the first stage unit... 11 The base of the signal generator is connected to the square wave trigger signal Q through the second capacitor C0 and resistor R0. 11 The collector is connected to the second avalanche transistor Q in the first stage unit. 12 The emitter and base are connected in the same manner, the third and fourth are connected in the same way, and the fourth avalanche transistor Q is connected in the same manner. 14 The collector is connected to the first isolation resistor R. c1 It is connected to the DC power supply terminal Vcc, and the first capacitor C1 is connected through a through-hole to the first avalanche transistor Q of the second stage unit. 21 The base and emitter are connected, and the same applies to the second to fourth stages, with each stage connected sequentially via a through-hole; the first avalanche transistor Q in the second to fourth stages... 21 Q 31 Q 41 The emitters are all connected through a second isolation resistor R' c1 、R' c2 、R' c3 Grounded, the fourth avalanche transistor Q in the last stage unit 44 The collector of the capacitor is connected to one end of the first capacitor C4, and the first capacitor C4 is connected to the load R. L Grounding. 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 is connected to the first isolation resistor R. c1 ~R c3 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 Charging capacitor C4 causes the avalanche transistor Q to... 11 ~Q 44 It operates in the critical avalanche region. Upon completion of charging, an external trigger signal activates the avalanche transistor Q. 11 To activate, please use Q in sequence. 12 ~Q 14 Overvoltage turn-on triggers the first capacitor C1 to activate the avalanche transistor Q. 11 ~Q 14 Discharge forming circuit C1-Q 14 -Q 13 -Q 12 -Q11 -R' c1 -C1, in R' c1 A negative pulse is generated on Q, causing Q to... 21 A voltage ramp is generated on Q, resulting in dv / dt. 21 When the voltage across both ends exceeds a certain withstand voltage, it subsequently overvoltages and turns on, causing C2 and C1 to discharge in series, forming a circuit 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, and then the remaining avalanche transistors are turned on sequentially, causing capacitors C1 to C4 to discharge in series, ultimately discharging at the load R. L A high-voltage target pulse signal is generated, completing one pulse discharge.

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

[0087] For a traditional single-sided layout, all loops occur on one side of the circuit board. The 4×4 level Marx generator circuit has three long connections on the PCB, each approximately 27mm long. As shown in Table 1, the paths on the PCB were extracted using the Ansys Slwave simulation tool and imported into the Ansys Q3D simulation tool. The parasitic inductances at each long connection were found to be 18.2621nH, 18.7925nH, and 18.2391nH, respectively, totaling 55.2937nH when added together.

[0088] According to the novel double-sided layout 4×4 stage Marx generator circuit proposed in the embodiments of this application, the capacitor connected to the fourth avalanche transistor in each stage of the charge-discharge cascade unit is connected to the base of the first avalanche transistor in the next stage through a through hole. This can transform the 27mm long connection of the planar loop into a vertical loop with a thickness of only 2mm, thereby greatly reducing the parasitic inductance of the line.

[0089] Table 1

[0090]

[0091] Furthermore, in the embodiments of this application, as shown in Table 1, simulation results show that the parasitic inductances at the three vias and the shorter, necessary connections are 4.7013nH, 1.7541nH, and 2.8334nH, respectively, totaling only 9.2888nH. This represents a significant improvement in parasitic inductance compared to the traditional single-sided layout, representing an 83.20% improvement. The magnitude of the parasitic inductance affects the amplitude, rise time, pulse quality, and turn-on stability 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 This is a schematic diagram comparing the experimental results of the output pulse signals of the Marx generator provided in this application embodiment with those of a conventional Marx generator, as shown below. Figure 4 As shown in the embodiments of this application, simulation experiments have verified that the Marx generator of this embodiment can generate an output pulse with an amplitude of 2.50kV and a rise time of 1.93ns. Compared with a conventional single-sided Marx generator of the same specifications, its output pulse amplitude is 1.79kV and its rise time is 4.76ns under the same test conditions. The Marx generator of this embodiment improves the pulse amplitude and rise time by 39.7% and 59.5%, respectively.

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

[0094] The Marx generator in this application embodiment is constructed by using a four-stage charge-discharge cascade unit, each stage of which includes four avalanche transistor modules. By adopting 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 above embodiments, as an optional embodiment, a DC power input terminal and a ground terminal are provided on one side and the other side of the double-sided PCB board; 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 and the second direction are opposite.

[0096] Specifically, in the embodiments of this application, because the emitter of the first avalanche transistor in each stage unit needs to be connected to the second isolation resistor R' c1 ~R' c(N-1) Grounding (except for the avalanche transistor Q in the first-stage unit) 11 (The emitter is directly grounded), and the collector of the fourth avalanche transistor in each stage unit must be connected through the first isolation resistor R. c1 ~R cN Connecting the DC power input terminal to Vcc (which provides power) and introducing through-holes on a double-sided PCB board will inevitably cause the cascaded circuit of two adjacent avalanche transistors to be upside down.

[0097] Therefore, in this embodiment, Vcc and ground terminals are designed on both the front and back sides of the double-sided PCB board. To prevent high voltage (such as the high voltage of four avalanche transistor module circuits reaching 1300V) from causing breakdown of the PCB board, the Vcc and ground terminals on the front and back sides are completely staggered. That is, the Vcc and ground terminals on one side of the double-sided PCB board are arranged along a first direction, and the Vcc and ground terminals on the other side of the double-sided PCB board are arranged along the opposite second direction. Furthermore, the Vcc terminals on each side can be connected to a DC power supply through two 1-to-2 power lines to complete the power supply.

[0098] The Marx generator of this application embodiment, with its double-sided layout on a double-sided PCB board, adopts a double-sided design and staggers the DC power input terminal and ground terminal. This effectively prevents the impact of high voltage on the operation of the generator circuit, avoids the risk of high voltage damaging the PCB board and burning out electronic components, and further improves the stability and reliability of the Marx generator operation.

[0099] The following describes the operation method of the Marx generator provided by the present invention. The operation method of the Marx generator described below can be referred to in correspondence with the Marx generator described above.

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

[0101] Step S1: Charge the cascaded charge and discharge units of each stage on the double-sided PCB board.

[0102] Step S2: After each level of the charge-discharge cascade unit has completed charging and the first level unit in the N-level charge-discharge cascade unit has received a trigger signal, each level of the charge-discharge cascade unit is sequentially driven to discharge.

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

[0104] It should be understood that the above-described device is used to execute the methods in the above embodiments. The implementation principle and technical effect of the corresponding program modules in the device are similar to those described in the above methods. The working process of the device can be referred to the corresponding process in the above methods, and will not be repeated here.

[0105] The Marx generator operation method of this application embodiment 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 an alternating order on both sides of the double-sided PCB board and electrically connecting them using pre-set through holes in the double-sided PCB board, the line length between the charge-discharge cascade units can be greatly shortened, effectively reducing the parasitic inductance of the internal circuit of the Marx generator, generating pulse output with higher amplitude and shorter rise time, and greatly improving the quality of the pulse signal output by the Marx generator.

[0106] It should be understood that expressions such as “comprising” and “may include” used in this 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 this application, terms such as “comprising” and / or “having” are to be interpreted as indicating a particular characteristic, number, operation, constituent element, component, or combination thereof, but not to exclude 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 this application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. 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. "Fixed connection" refers to a connection where the relative positional relationship remains unchanged after connection. "Rotary connection" refers to a connection where the two parts can rotate relative to each other after connection. "Sliding connection" refers to a connection where the two parts can slide relative to each other after connection.

[0108] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A Marx generator, characterized in that, include: Double-sided PCB board and N-stage charge / discharge cascaded units connected in sequence; In the N-level charge-discharge cascaded unit, each first unit with an odd cascade order is arranged sequentially on one side of the double-sided PCB board, and each second unit with an even cascade order is arranged sequentially on the other side of the double-sided PCB board; each first unit and its adjacent second unit are electrically connected through a pre-set through hole in the double-sided PCB board, wherein the value of N ranges from 4 to 10. The first stage unit in the N-stage charge-discharge cascade unit is used to drive the generator to perform avalanche discharge when each stage of the charge-discharge cascade unit has completed charging and a trigger signal has been received; the last stage unit is used to connect to the load to generate a target pulse signal at both ends of the load. Each of the charge-discharge cascaded units includes multiple avalanche transistor modules connected in sequence, with the last avalanche transistor module serving as the signal input side and the first avalanche transistor module serving as the signal output side. The avalanche transistor module includes an avalanche transistor and a resistor connected in parallel across the avalanche transistor. Each stage of the charge-discharge cascade unit also includes a first capacitor and a first isolation resistor; one end of the first isolation resistor in each stage of the charge-discharge cascade unit is connected together as a DC power input terminal; the other end of the first isolation resistor in each stage of the charge-discharge cascade unit is connected to one end of its respective first capacitor and connected to its respective last avalanche transistor module. Except for the last stage 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 stage charge-discharge cascade unit; the other end of the first capacitor in the last stage unit is connected to the load. The generator further includes a trigger signal processing unit, which is used to receive an external square wave signal when the generator has finished 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.

2. The Marx generator according to claim 1, characterized in that, In addition to the first-stage unit, each of the other charge-discharge cascaded units also includes a second isolation resistor; one end of the second isolation resistor in each stage is connected to its respective first avalanche transistor module, and the other end of the second isolation resistor in each stage is connected to the output terminal of the first avalanche transistor module in the first-stage unit and grounded.

3. The Marx generator according to claim 1, 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 together, and the other end of the resistor is connected to the emitter of the avalanche transistor in the first avalanche transistor module and grounded.

4. The Marx generator according to claim 3, characterized in that, The generator includes a four-stage charge-discharge cascade unit, and each stage of the charge-discharge cascade unit includes four avalanche transistor modules.

5. The Marx generator according to any one of claims 1-4, characterized in that, The double-sided PCB board has a DC power input terminal and a ground terminal on one side and the other side; 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 and the second direction are opposite.

6. The Marx generator according to any one of claims 1-4, characterized in that, The avalanche transistor includes the FMMT415 series transistor, the FMMT417 series transistor, or the C1815 series transistor.

7. A method of operating a Marx generator as described in any one of claims 1-6, characterized in that, include: The cascaded charge-discharge units connected in each stage on the double-sided PCB are charged. When each of the charging and discharging cascaded units completes charging and the first unit in the N-stage charging and discharging cascaded unit receives a trigger signal, each of the charging and discharging cascaded units is driven to discharge sequentially. The target pulse signal is generated at both ends of the load connected to the last stage unit in the N-stage charge-discharge cascade unit.

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