A design method of a cold cathode trigger tube circuit simulation SPICE model

Abstract

The application belongs to the technical field of cold cathode trigger tube, and discloses a cold cathode trigger tube circuit simulation SPICE design method, which comprises the following steps: main gap channel design; trigger gap channel design; control module design; cold cathode trigger tube characteristic parameter verification and problem analysis; cold cathode trigger tube SPICE model improvement based on gas discharge theory and characteristic parameter verification; improved cold cathode trigger tube application simulation and result analysis. The cold cathode trigger tube SPICE model provided by the application meets the functions of the modern cold cathode trigger tube, and is verified by simulation; and different parameters of the model can be modified to meet the requirements of different scenes.

Description

Technical Field

[0001] This invention belongs to the field of cold cathode trigger tube technology, and particularly relates to a SPICE design method for cold cathode trigger tube circuit simulation. Background Technology

[0002] As a type of triggered spark gap switch, the cold cathode trigger tube has some characteristics that cannot be replaced by other types of devices. It has a wide range of applications, mainly as a high-voltage pulse switch, used in various high-voltage pulse generators, aircraft engine ignition, and protection of high-voltage equipment and components. However, there is currently no SPICE model that is fully functional and simple and reliable. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a SPICE design method for cold cathode triggering tube circuit simulation.

[0004] This invention is implemented as follows: a SPICE design method for cold cathode triggering transistor circuit simulation, the method comprising:

[0005] S1: Main clearance channel design;

[0006] S2: Trigger gap channel design;

[0007] S3: Control module design;

[0008] S4: Verification of cold cathode trigger tube characteristic parameters and problem analysis;

[0009] S5: Improved SPICE model and characteristic parameter verification of cold cathode trigger tube based on gas discharge theory;

[0010] S6: Simulation and Result Analysis of the Application of the Improved Cold Cathode Trigger.

[0011] Furthermore, S1 specifically includes:

[0012] Under specific triggering conditions, when an external working voltage is applied to both ends of the main gap channel, the cold cathode trigger tube will exhibit either a working state or a non-working state depending on the magnitude and direction of the applied voltage. In the non-working state, the main gap channel of the cold cathode trigger tube will exhibit a large insulation resistance value, generally above 10MΩ, while the resistance value of the main gap channel of the trigger tube after conduction drops to a few tenths of an ohm, which is close to a short circuit state.

[0013] Furthermore, S2 specifically includes:

[0014] Under normal circumstances, when the voltage applied across the main gap channel is lower than the self-breakdown voltage of the trigger transistor, the trigger transistor will not break down and conduct. If a trigger pulse of a certain amplitude and width is applied to the trigger electrode, the trigger gap between the trigger electrode and the adjacent electrode breaks down and conducts, generating a discharge. This discharge process is the breakdown and conduction of the trigger transistor. Due to external uncertainties, a minimum trigger current I needs to be set to avoid mis-conduction of the trigger transistor. Tkmin .

[0015] Furthermore, S3 specifically includes:

[0016] (1) Self-breakdown voltage control module

[0017] The self-breakdown voltage of a cold cathode trigger tube is mainly affected by a combination of factors, including the type and pressure of the gas inside the tube, the distance between adjacent electrodes, the electrode material, size, shape, and surface condition of the electrodes. A formula for calculating the self-breakdown voltage of a cold cathode trigger tube based on three parameters—ionization constant, distance between adjacent electrodes, and gas pressure inside the trigger tube—is provided.

[0018]

[0019] In the formula: a is the gas constant; e is the gap distance between adjacent electrodes in the trigger tube; p is the gas pressure in the trigger tube;

[0020] The output voltages of three different DC voltage sources are used to replace the three parameters mentioned above, so as to realize the input of parameters and the calculation of self-breakdown voltage;

[0021] (2) Working voltage control module

[0022] An external trigger pulse with a certain amplitude and width is applied, and the required operating voltage is calculated from the general operating characteristic curve of the cold cathode trigger tube. However, the actual general operating characteristic curve of the cold cathode trigger tube is difficult to express in the form of a mathematical function.

[0023] (3) Operating current limiting module

[0024] According to the typical operating characteristic curve of a cold cathode trigger tube, when a large operating voltage is applied, a large operating current will appear in the main gap channel circuit, while a typical cold cathode trigger tube has a limited operating current range; when the main gap current is less than the maximum operating current I... opmax At that time, the voltage at node Open causes the voltage-controlled switch S_Open to close, closing the entire main gap channel, allowing the cold cathode trigger tube to work normally.

[0025] Furthermore, S4 specifically includes:

[0026] (1) Self-breakdown voltage test

[0027] Connect the tube under test, and slowly increase the DC voltage applied across the main gap within the specified voltage rise time until the main gap breaks down. Record the breakdown voltage value, which is the self-breakdown voltage value of the trigger tube.

[0028] (2) Self-breakdown voltage test

[0029] Connect the tube under test, apply the specified working voltage across the main gap, gradually increase the trigger voltage to make the trigger tube work, and record the DC voltage value of the trigger tube at this time, which is the minimum trigger voltage of the trigger tube.

[0030] (3) Working voltage range test

[0031] Connect the tube under test, and under the specified triggering conditions, gradually increase the DC voltage applied across the main gap to make the trigger tube work, and record the DC voltage value, which is the minimum operating voltage of the trigger tube.

[0032] (4) Operating current range test

[0033] Connect the tube under test, apply the specified trigger voltage and operating voltage to make the trigger tube work normally, and measure the maximum operating current value.

[0034] Furthermore, S5 specifically includes:

[0035] (1) Gap switch control;

[0036] (2) Channel resistance;

[0037] (3) Channel inductance;

[0038] (4) Model validation and parameter setting.

[0039] Furthermore, step (1) includes:

[0040] The breakdown of the gas discharge switch is equivalent to the closing of the voltage-controlled switch S_Ch. The closing of S_Ch is controlled by the voltage source B_Ch_On, and its output is determined by the logic composed of V(Delay_Over) and V(Maintain). If either V(Delay_Over) or V(Maintain) is greater than 0.5V, then the output of B_Ch_On is 1V, and the switch S_Ch is turned on. The presence of resistor R1 and capacitor C1 provides a finite time for the rise of the node voltage V(Ch_On), thereby ensuring that the transition time of switch S_Ch is finite.

[0041] Breakdown delay:

[0042] The node voltage V(Delay_Over) is determined by the behavioral voltage source B_Dly_Ovr, and its output is a logic decision expression. If the node voltage V(T_Over) is greater than V(delay), it is true, the output jumps to 1V, and the switch S_Ch closes. These two nodes represent the time when the gap voltage exceeds the static breakdown voltage and the breakdown delay time, respectively.

[0043] The time during which the gap voltage exceeds the static breakdown voltage is represented by the voltage at node T_Over, generated by the behavioral voltage source B_T_Ovr. Its output is the simulation time minus the voltage value at node T_B, in seconds. When V(Over) is greater than 0.5V, B_! When Ovr drops from 1V to 0V, switch S1 turns off—freezing the voltage of C2, and thus freezing the voltage of node T_B. The voltage value of node Over is generated by voltage source B_Ovr, whose output is an IF statement. If the gap voltage is greater than the static breakdown voltage, the output is 1V; otherwise, it remains 0V. Here, when the IF statement condition is true, the result uses the tanh function to smooth the transition of switch S1 from the off to the on state, so as to avoid discontinuities that prevent the convergence of the simulation solution. The gap voltage is represented by the voltage at node V_Gap, generated by behavioral voltage source B_V_Gap, whose output is the absolute value of the voltage difference between nodes T1 and T2. The static breakdown voltage is represented by the voltage at node V_Break, generated by behavioral voltage source B_V_Brk, whose output uses the following formula, which is applicable to very small gaps under high voltage, and the unit is kV.

[0044]

[0045] The breakdown delay time is the time from when the gas discharge switch exceeds the static breakdown voltage to when the switch closes and the channel is turned on. It is expressed as the voltage at the node delay and is generated by the behavioral voltage source B_Dly. Its output is determined by Martin's empirical formula and is in seconds.

[0046]

[0047] In the formula: E is the gap electric field, in kV / cm, calculated at node E_Gap, generated by the behavioral voltage source B_E_Gap, and its output is the ratio of node voltage V_Gap to channel spacing D; ρ is the gap gas volume density, in g / cm3, calculated at node Rho_V, generated by the behavioral voltage source B_Rho, and its output is related to the gap gas pressure and atmospheric pressure.

[0048] Channel sustaining current:

[0049] After switch S_Ch is initially closed, the gap voltage will drop rapidly, and the current will begin to fill the entire loop. To maintain the continuity of switch S_Ch closure, it is assumed that there is a minimum current value. When the channel current is greater than this minimum value, the breakdown delay issue does not need to be considered, and the switch will remain closed, with B_Ch_On maintaining an output of 1V. This minimum current value is represented by node I_Min and is generated by the DC voltage source B_I_Min. When the channel current I_Ch is greater than this minimum value, the output V(Maintain) is 1V. The channel current I_Ch is represented by the voltage at node I_Ch and is generated by the behavioral current source B_I_Ch, whose output is the absolute value of the channel current.

[0050] Furthermore, step (2) includes:

[0051] The output of voltage source B_Res is the product of its own current and the voltage at node R_Ch, representing the channel gap resistance after the gas discharge switch is broken down, in Ω; a formula for calculating the channel resistance based on three parameters: gap distance, channel radius, and channel current:

[0052]

[0053] Where c is the given proportionality constant 876, d is the gap distance, i is the channel current, and r is the calculated channel radius in meters;

[0054]

[0055] Where i is the channel current in kA, t is the channel formation time in μs, and ρ is the interstitial gas density in g / cm³. 3 The formula is used by the current source B_Ch_Rad to drive the voltage at node Ch_Rad, which represents the channel radius. D4 limits the charging of C5 to the peak output of B_Ch_Rad, and then decays it through R3. This combination exists because the derivation of the channel radius calculation formula proposed by Braginskii only considers the pulse-driven channel growth and does not ignore any contraction or dissipation. At the same time, when the channel is not conducting, a switch controlled by the voltage of node Ch_On can be used to keep C6 discharging. The Braginskii channel radius expression requires the time after arc formation as an input variable. Therefore, a circuit is added to the model to calculate the time of the last transition of switch S_Ch from off to on. This time is represented by the voltage of node T_Arc and is generated in the same way as the overvoltage time described above. The logic inverse of the voltage of node Ch_On is used as the control signal of the sample and hold circuit, which determines the arc start time of node T_C.

[0056] Furthermore, step (3) specifically includes:

[0057] In the main circuit, the closed-loop inductance is modeled using a behavioral current source B_Ind. The voltage across the inductor is converted into current by B_Ind, and the current is integrated through capacitor C4. The result of the integration generates a voltage at node Int_V_L, with units of V∙S×10⁹. The current generated by B_Ind is then set as the voltage at Int_V_L divided by the voltage at L_Ch, which represents the channel inductance in nH. The voltage at node L_Ch is generated by the voltage source B_L_Ch, and its output uses the inductance expression of an isolated thin line, with units of nH.

[0058]

[0059] In the formula: d is the gap distance, in cm; r is the channel radius, in m;

[0060] The output of voltage source B_L_Ch uses the limit function because when the inductance is too small, the output of voltage source B_Ind will reach infinity. For a small channel radius, setting an upper limit prevents the inductance from becoming too large.

[0061] Furthermore, step (4) specifically includes:

[0062] A trigger voltage with a certain amplitude and width is applied to activate switches S3 and S4. Capacitors C7 and C8 have initial voltages of the same magnitude but opposite directions. When the switches are activated, capacitors C7 and C8 begin to discharge. The lossy transmission line Rg218 is used to simulate the same type of coaxial cable connecting the pulse transmitter and the test unit.

[0063] Based on the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solution to be protected by this invention are as follows:

[0064] First, the SPICE model of the cold cathode trigger tube proposed in this invention meets the functions of modern cold cathode trigger tubes and has been verified by simulation. Furthermore, the model can be modified with different parameters to meet the needs of different scenarios.

[0065] This invention, using the simulation software LTspice, focuses on the model design, characteristic parameter testing, improvement, and simulation verification of a cold cathode trigger tube. This invention proposes and studies a novel SPICE model of a cold cathode trigger tube. Under set parameters, its self-breakdown voltage is 15.51kV, the minimum trigger voltage is 3.00kV, the operating voltage range is 7.03-10.00kV, and the operating current is less than 7.14kA. All characteristic parameters conform to the detailed specifications of the RQ-10 type cold cathode trigger tube. To address the issues of self-breakdown and uncontrollable conduction delay time, two improved cold cathode trigger tube models (Type I and Type II) were designed. The gas discharge switch used in these models is based on the gas discharge principle. When pulses arrive at the measurement unit simultaneously, a voltage approximately 3.5 times the initial charging voltage of the capacitor appears on the switch. The pulse arrival time at the switch is approximately 3ns, the peak duration is approximately 8ns, and the rise and fall times are both approximately 8ns. To verify the correctness of these two improved cold cathode trigger tubes, parameter characteristic simulations were performed on both types as described above. The results were similar to those of the original model. To verify the universality of these two improved cold cathode trigger tubes, application simulations were conducted on the two improved cold cathode trigger tube models in three mainstream circuit simulation software programs: Ltspice, Multisim, and PSpice. Under applied operating voltages of 16kV, 18kV, and 20kV, the improved cold cathode trigger tube (Type I) effectively suppressed self-breakdown. For the improved cold cathode trigger tube (Type II), the effects of gap distance, gas pressure, and gap voltage on the conduction delay time were simulated. The simulation results showed that the conduction delay time was directly proportional to the gap distance and gas pressure, and inversely proportional to the gap voltage. Under the parameter conditions set in this invention, the conduction delay time ranged from 81.30ns to 481.71ns.

[0066] Secondly, the SPICE model of the cold cathode trigger tube proposed in this invention meets the functional requirements of modern cold cathode trigger tubes, and simulation verification has been performed. Furthermore, the model can be modified with different parameters to meet the needs of different scenarios. Addressing some issues discovered during simulation verification, improved cold cathode trigger tube models (Type I and Type II) are proposed based on the gas discharge principle. These two improved models effectively solve the self-breakdown phenomenon and uncontrollable conduction delay time problems of traditional cold cathode trigger tubes, respectively. Simulation verification has been performed using three mainstream circuit simulation software programs: LTspice, Multisim, and PSpice. The simulation results further verify the universality of the model established in this invention and its strong feasibility, laying the foundation for subsequent research.

[0067] Third, as supplementary evidence of the inventive step of the claims of this invention, it is also reflected in the following important aspects:

[0068] (1) The expected benefits and commercial value of the technical solution of this invention after transformation;

[0069] (2) The technical solution of this invention fills a technical gap in the industry both domestically and internationally;

[0070] (3) Whether the technical solution of the present invention solves the technical problem that people have long wanted to solve but have never been able to solve successfully;

[0071] (4) Whether the technical solution of the present invention overcomes technical bias. Attached Figure Description

[0072] Figure 1 This is the main gap channel circuit provided in the embodiments of the present invention;

[0073] Figure 2 This is the trigger gap channel circuit provided in the embodiments of the present invention;

[0074] Figure 3 This is the self-breakdown voltage control module provided in the embodiments of the present invention;

[0075] Figure 4 This is a general characteristic curve of the cold cathode trigger tube provided in the embodiments of the present invention;

[0076] Figure 5 This is an approximate polyline provided in the embodiments of the present invention;

[0077] Figure 6 This is the minimum trigger voltage control module provided in the embodiments of the present invention;

[0078] Figure 7 This is the operating current limiting module provided in the embodiments of the present invention;

[0079] Figure 8 This is a circuit diagram for a self-breakdown voltage test provided in an embodiment of the present invention;

[0080] Figure 9 This is a simulation waveform diagram of the self-breakdown voltage test provided in an embodiment of the present invention;

[0081] Figure 10 This is a circuit diagram for testing the minimum trigger voltage provided in an embodiment of the present invention;

[0082] Figure 11 This is a simulation waveform diagram of the minimum trigger voltage test provided in an embodiment of the present invention;

[0083] Figure 12 This is a simulation waveform diagram of the lowest operating voltage test provided in an embodiment of the present invention;

[0084] Figure 13This is the highest operating voltage test simulation waveform provided in the embodiments of the present invention;

[0085] Figure 14 These are simulation waveforms for testing the operating current range provided in this embodiment of the invention;

[0086] Figure 15 This is the main circuit of the gas discharge switch provided in the embodiment of the present invention;

[0087] Figure 16 This is the gap switch control module provided in the embodiments of the present invention;

[0088] Figure 17 This is the channel resistance calculation module provided in the embodiments of the present invention;

[0089] Figure 18 This is the gas discharge switch verification circuit provided in the embodiment of the present invention;

[0090] Figure 19 This is the verification waveform of the gas discharge switch provided in the embodiment of the present invention;

[0091] Figure 20 This is the self-breakdown suppression module provided in the embodiments of the present invention;

[0092] Figure 21 This is the static breakdown voltage reduction module provided in the embodiments of the present invention;

[0093] Figure 22 This is an improved cold cathode trigger tube model (Type I) (main gap channel) provided in the embodiments of the present invention.

[0094] Figure 23 This is an improved cold cathode trigger tube model (Type II) (trigger gap channel) provided in the embodiments of the present invention.

[0095] Figure 24 This is a simulation waveform diagram of the self-breakdown voltage test provided in an embodiment of the present invention;

[0096] Figure 25 This is a simulation waveform diagram of the minimum trigger voltage test provided in an embodiment of the present invention;

[0097] Figure 26 This is a simulation waveform diagram of the lowest operating voltage test provided in an embodiment of the present invention;

[0098] Figure 27 This is a simulation waveform diagram of the highest operating voltage test provided in the embodiments of the present invention;

[0099] Figure 28 This is a simulation waveform diagram of the operating current range test provided in an embodiment of the present invention;

[0100] Figure 29The improved cold cathode trigger tube model (Type I) provided in the embodiments of the present invention has the following self-breakdown suppression effects: (a) self-breakdown suppression effect (16kV); (b) self-breakdown suppression effect (18kV); (c) self-breakdown suppression effect (20kV). Detailed Implementation

[0101] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0102] This invention provides a SPICE design method for cold cathode trigger transistor circuit simulation, the method comprising:

[0103] S1: Main clearance channel design;

[0104] S2: Trigger gap channel design;

[0105] S3: Control module design;

[0106] S4: Verification of cold cathode trigger tube characteristic parameters and problem analysis;

[0107] S5: Improved SPICE model and characteristic parameter verification of cold cathode trigger tube based on gas discharge theory;

[0108] S6: Simulation and Result Analysis of the Application of the Improved Cold Cathode Trigger.

[0109] S1 specifically includes:

[0110] Under specific triggering conditions, when an external working voltage is applied to both ends of the main gap channel, the cold cathode trigger tube will exhibit either a working state or a non-working state depending on the magnitude and direction of the applied voltage. In the non-working state, the main gap channel of the cold cathode trigger tube will exhibit a large insulation resistance value, generally above 10MΩ, while the resistance value of the main gap channel of the trigger tube after conduction drops to a few tenths of an ohm, which is close to a short circuit state. Figure 1 In this diagram, R_On and R_Off represent the channel resistance of the main gap channel in the working and non-working states, respectively; C_On and L_On represent the distributed capacitance and distributed inductance of the main gap channel in the conducting state, respectively; and C_Off and L_Off represent the distributed capacitance and distributed inductance of the main gap channel in the non-conducting state, respectively. The output voltages of the behavioral voltage sources B_E_FwBreak and B_E_ReBreak represent the forward and reverse breakdown threshold voltages, respectively. The output voltage of the behavioral voltage source B_E_On represents the working voltage of the main gap channel. D1, D2, and D3 serve as shunt switches for the three branches. The voltage-controlled switch S_Open is used to limit the working current of the main gap channel.

[0111] S2 specifically includes:

[0112] Under normal circumstances, when the voltage applied across the main gap channel is lower than the self-breakdown voltage of the trigger transistor, the trigger transistor will not break down and conduct. If a trigger pulse of a certain amplitude and width is applied to the trigger electrode, the trigger gap between the trigger electrode and the adjacent electrode breaks down and conducts, generating a discharge. This discharge process is the breakdown and conduction of the trigger transistor. Due to external uncertainties, a minimum trigger current I needs to be set to avoid mis-conduction of the trigger transistor. Tkmin . Figure 2 In this context, W1 acts as a current-controlled switch; when the trigger gap channel current is greater than I... Tkmin When the switch is closed, the trigger pulse can reach the adjacent electrode. R_Tk, C_Tk and L_Tk represent the distributed resistance, distributed inductance and distributed capacitance of the trigger gap channel circuit, respectively.

[0113] Furthermore, S3 specifically includes:

[0114] (1) Self-breakdown voltage control module

[0115] The self-breakdown voltage of a cold cathode trigger tube is mainly affected by a combination of factors, including the type and pressure of the gas inside the tube, the distance between adjacent electrodes, the electrode material, size, shape, and surface condition of the electrodes. A formula for calculating the self-breakdown voltage of a cold cathode trigger tube based on three parameters—ionization constant, distance between adjacent electrodes, and gas pressure inside the trigger tube—is provided.

[0116]

[0117] In the formula: a is the gas constant; e is the gap distance between adjacent electrodes in the trigger tube; p is the gas pressure in the trigger tube;

[0118] The output voltages of three different DC voltage sources are used to replace the three parameters mentioned above, thus realizing the input of parameters and the calculation of self-breakdown voltage; for example... Figure 3 As shown, R_A, R_D, and R_P represent the series internal resistances of the three DC voltage sources, respectively.

[0119] (2) Working voltage control module

[0120] An external trigger pulse with a certain amplitude and width is applied. The required operating voltage can be calculated from the general operating characteristic curve of a cold cathode trigger tube. However, the actual general operating characteristic curve of a cold cathode trigger tube is difficult to express in the form of a mathematical function; for example... Figure 4As shown. Here, a TBL-type current source in LTspice is used to simulate the characteristic curve. According to the requirements of a TBL-type current source, different outputs cannot be obtained with the same input. Therefore, an approximation is made to the general characteristic curve of the cold cathode trigger tube, that is, data from as many key nodes as possible are taken to clamp several points on the curve, resulting in the following... Figure 5 The relationship shown is represented by a broken line.

[0121] like Figure 6 As shown, the behavioral voltage source B_Tril provides the absolute value of the applied trigger voltage to the TBL-type current source G_Omin, so that the output of G_Omin is numerically the same as the operating voltage VAK corresponding to the approximate processing piecewise linear curve of the cold cathode trigger tube. The resistor R_Omin is the equivalent series internal resistance of B_Tril and G_Omin. The voltage value of node Tmin is generated by the behavioral voltage source B_Tmin, representing the set minimum trigger voltage VTmin. The voltage of node Ctrl is generated by the behavioral voltage source B_Ctrl, and its output uses an IF statement.

[0122] (3) Operating current limiting module

[0123] like Figure 7 As shown, according to the general operating characteristic curve of a cold cathode trigger tube, when a large operating voltage is applied, a large operating current will appear in the main gap channel circuit, while a typical cold cathode trigger tube has a limited operating current range; when the main gap current is less than the maximum operating current I... opmax At that time, the voltage at node Open causes the voltage-controlled switch S_Open to close, closing the entire main gap channel, allowing the cold cathode trigger tube to work normally.

[0124] S4 specifically includes:

[0125] (1) Self-breakdown voltage test

[0126] like Figure 8 As shown, connect the tube under test, and slowly increase the DC voltage applied across the main gap within a specified voltage rise time until the main gap breaks down. Record this breakdown voltage value, which is the self-breakdown voltage value of the trigger tube. Keep the output voltage of the behavioral voltage source B_Open constant at 1V, so that the voltage-controlled switch S_Open remains closed. Voltage source V3 generates a pulse voltage with an initial value of 0, a peak value of 30kV, a delay time of 0s, a rise time of 50ns, a duration of 0s, and a fall time of 50ns. CTT is the equivalent model of the cold cathode trigger tube. The measurement of the main gap channel current is equivalent to measuring the current flowing through the resistor R_On. The simulation waveform is shown below. Figure 9 As shown.

[0127] (2) Self-breakdown voltage test

[0128] like Figure 10 As shown, connect the tube under test, apply the specified working voltage across the main gap, and gradually increase the trigger voltage to activate the trigger tube. Record the DC voltage value of the trigger tube at this point; this is the minimum trigger voltage of the trigger tube. Voltage source V3 generates a constant DC voltage with an amplitude of 9kV, and voltage source V4 generates a pulse voltage with an initial value of 0, a peak value of 30kV, a delay time of 0s, a rise time of 50ns, a duration of 0s, and a fall time of 50ns. The simulated waveform is shown below. Figure 11 As shown.

[0129] (3) Working voltage range test

[0130] according to Figure 10 Connect the tube under test. Under the specified triggering conditions, gradually increase the DC voltage applied across the main gap to activate the trigger tube, and record this DC voltage value, which is the minimum operating voltage of the trigger tube. Voltage source V3 generates a pulse voltage with an initial value of 0, a peak value of 10kV, a delay time of 0s, a rise time of 50ns, a duration of 0s, and a fall time of 50ns. Voltage source V4 generates a constant DC voltage with an amplitude of 20kV. The simulated waveform is as follows. Figure 12 As shown.

[0131] Based on the test results, the minimum trigger voltage of the trigger tube is WTmin = 3.00kV. If the output of DC voltage source V4 is changed to be slightly greater than WTmin, the peak output of voltage source V3 will change to 15kV. Record the moment when the trigger tube starts working and record the DC voltage value, which is the maximum operating voltage of the trigger tube.

[0132] (4) Operating current range test

[0133] according to Figure 10 Connect the transistor under test, apply the specified trigger voltage and operating voltage to enable the trigger transistor to operate normally, and measure the maximum operating current value. Voltage source V3 generates a pulse voltage with an initial value of 0, a peak value of 15kV, a delay time of 0s, a rise time of 50ns, a duration of 150ns, and a fall time of 10ns. Voltage source V4 generates a pulse voltage with an initial value of 0, a peak value of 20kV, a delay time of 0s, a rise time of 50ns, a duration of 0s, and a fall time of 50ns. The simulated waveforms are as follows: Figure 14 As shown.

[0134] Furthermore, S5 specifically includes:

[0135] The basic circuit of a gas discharge switch consists of four basic components. T1 and T2 serve as the input and output terminals of the external power supply. The current source B_Ind represents the distributed inductance of the channel. The voltage-controlled switch S_Ch controls the conduction and disconnection of the channel. The voltage source B_Res represents the distributed resistance of the channel. These three components are connected in series and then in parallel with C_Gap, which represents the distributed capacitance of the channel. The basic circuit configuration is as follows: Figure 15 As shown.

[0136] (1) Gap switch control;

[0137] (2) Channel resistance;

[0138] (3) Channel inductance;

[0139] (4) Model validation and parameter setting.

[0140] Furthermore, such as Figure 16 As shown, step (1) includes:

[0141] The breakdown of the gas discharge switch is equivalent to the closing of the voltage-controlled switch S_Ch. The closing of S_Ch is controlled by the voltage source B_Ch_On, and its output is determined by the logic composed of V(Delay_Over) and V(Maintain). If either V(Delay_Over) or V(Maintain) is greater than 0.5V, then the output of B_Ch_On is 1V, and the switch S_Ch is turned on. The presence of resistor R1 and capacitor C1 provides a finite time for the rise of the node voltage V(Ch_On), thereby ensuring that the transition time of switch S_Ch is finite.

[0142] Breakdown delay:

[0143] The node voltage V(Delay_Over) is determined by the behavioral voltage source B_Dly_Ovr, and its output is a logic decision expression. If the node voltage V(T_Over) is greater than V(delay), it is true, the output jumps to 1V, and the switch S_Ch closes. These two nodes represent the time when the gap voltage exceeds the static breakdown voltage and the breakdown delay time, respectively.

[0144] The time during which the gap voltage exceeds the static breakdown voltage is represented by the voltage at node T_Over, generated by the behavioral voltage source B_T_Ovr. Its output is the simulation time minus the voltage value at node T_B, in seconds. When V(Over) is greater than 0.5V, B_! When Ovr drops from 1V to 0V, switch S1 turns off—freezing the voltage of C2, and thus freezing the voltage of node T_B. The voltage value of node Over is generated by voltage source B_Ovr, whose output is an IF statement. If the gap voltage is greater than the static breakdown voltage, the output is 1V; otherwise, it remains 0V. Here, when the IF statement condition is true, the result uses the tanh function to smooth the transition of switch S1 from the off to the on state, so as to avoid discontinuities that prevent the convergence of the simulation solution. The gap voltage is represented by the voltage at node V_Gap, generated by behavioral voltage source B_V_Gap, whose output is the absolute value of the voltage difference between nodes T1 and T2. The static breakdown voltage is represented by the voltage at node V_Break, generated by behavioral voltage source B_V_Brk, whose output uses the following formula, which is applicable to very small gaps under high voltage, and the unit is kV.

[0145]

[0146] The breakdown delay time is the time from when the gas discharge switch exceeds the static breakdown voltage to when the switch closes and the channel is turned on. It is expressed as the voltage at the node delay and is generated by the behavioral voltage source B_Dly. Its output is determined by Martin's empirical formula and is in seconds.

[0147]

[0148] In the formula: E is the gap electric field, in kV / cm, calculated at node E_Gap, generated by the behavioral voltage source B_E_Gap, and its output is the ratio of node voltage V_Gap to channel spacing D; ρ is the gap gas volume density, in g / cm3, calculated at node Rho_V, generated by the behavioral voltage source B_Rho, and its output is related to the gap gas pressure and atmospheric pressure.

[0149] Channel sustaining current:

[0150] After switch S_Ch is initially closed, the gap voltage will drop rapidly, and the current will begin to fill the entire loop. To maintain the continuity of switch S_Ch closure, it is assumed that there is a minimum current value. When the channel current is greater than this minimum value, the breakdown delay issue does not need to be considered, and the switch will remain closed, with B_Ch_On maintaining an output of 1V. This minimum current value is represented by node I_Min and is generated by the DC voltage source B_I_Min. When the channel current I_Ch is greater than this minimum value, the output V(Maintain) is 1V. The channel current I_Ch is represented by the voltage at node I_Ch and is generated by the behavioral current source B_I_Ch, whose output is the absolute value of the channel current.

[0151] like Figure 17 As shown, step (2) includes:

[0152] The output of voltage source B_Res is the product of its own current and the voltage at node R_Ch, representing the channel gap resistance after the gas discharge switch is broken down, in Ω; a formula for calculating the channel resistance based on three parameters: gap distance, channel radius, and channel current:

[0153]

[0154] Where c is the given proportionality constant 876, d is the gap distance, i is the channel current, and r is the calculated channel radius in meters;

[0155]

[0156] Where i is the channel current in kA, t is the channel formation time in μs, and ρ is the interstitial gas density in g / cm³. 3 The formula is used by the current source B_Ch_Rad to drive the voltage at node Ch_Rad, which represents the channel radius. D4 limits the charging of C5 to the peak output of B_Ch_Rad, and then decays it through R3. This combination exists because the derivation of the channel radius calculation formula proposed by Braginskii only considers the pulse-driven channel growth and does not ignore any contraction or dissipation. At the same time, when the channel is not conducting, a switch controlled by the voltage of node Ch_On can be used to keep C6 discharging. The Braginskii channel radius expression requires the time after arc formation as an input variable. Therefore, a circuit is added to the model to calculate the time of the last transition of switch S_Ch from off to on. This time is represented by the voltage of node T_Arc and is generated in the same way as the overvoltage time described above. The logic inverse of the voltage of node Ch_On is used as the control signal of the sample and hold circuit, which determines the arc start time of node T_C.

[0157] Step (3) specifically includes:

[0158] In the main circuit, the closed-loop inductance is modeled using a behavioral current source B_Ind. The voltage across the inductor is converted into current by B_Ind, and the current is integrated through capacitor C4. The result of the integration generates a voltage at node Int_V_L, with units of V∙S×10⁹. The current generated by B_Ind is then set as the voltage at Int_V_L divided by the voltage at L_Ch, which represents the channel inductance in nH. The voltage at node L_Ch is generated by the voltage source B_L_Ch, and its output uses the inductance expression of an isolated thin line, with units of nH.

[0159]

[0160] In the formula: d is the gap distance, in cm; r is the channel radius, in m;

[0161] The output of voltage source B_L_Ch uses the limit function because when the inductance is too small, the output of voltage source B_Ind will reach infinity. For a small channel radius, setting an upper limit prevents the inductance from becoming too large.

[0162] Step (4) specifically includes:

[0163] like Figure 18 As shown, a trigger voltage with a certain amplitude and width is applied to activate switches S3 and S4. Capacitors C7 and C8 have initial voltages of the same magnitude but opposite directions. When the switches are activated, capacitors C7 and C8 begin to discharge. The lossy transmission line Rg218 is used to simulate the same type of coaxial cable connecting the pulse transmitter and the test unit.

[0164] like Figure 19 As shown, when the pulses arrive at the measuring unit simultaneously, a voltage approximately 3.5 times the initial charging voltage of the capacitor appears on the switch. The time for the pulses to reach the gas discharge switch is approximately 3 ns, the peak duration is approximately 8 ns, and the rise and fall times are both approximately 8 ns.

[0165] like Figure 20 As shown, when the input voltage is greater than the self-breakdown voltage of the cold cathode trigger tube, the gap channel will not be open, and theoretically no current will flow through the main gap channel of the cold cathode trigger tube, thereby suppressing the self-breakdown phenomenon of the cold cathode trigger tube.

[0166] like Figure 21As shown, the principle is to introduce a weakening coefficient r. The existence of r ensures that the gap voltage is always greater than the static breakdown voltage. At the same time, the output voltage of node Over becomes a judgment on whether the voltage of node V_Gap is greater than the weakened static breakdown voltage V_Break_End, thereby ensuring that the switch can be broken down and turned on.

[0167] like Figure 22 As shown; the main circuit of the gas discharge switch and the static breakdown voltage reduction module are respectively added to the trigger gap channel circuit of the cold cathode trigger tube and the gas discharge switch control module to realize the function of controlling the conduction delay time of the cold cathode trigger tube, as shown. Figure 23 As shown.

[0168] Referring to the People's Republic of China Electronic Industry Standard for Cold Cathode Trigger Test Method, the improved cold cathode trigger tube SPICE model was tested and verified for its characteristic parameters. In the simulation, the verification circuit and parameter settings were the same as in Section 3. In the improved cold cathode trigger tube model (Type I), the gas discharge switch distributed capacitance C was set to 1pF, and diodes D1, D2, and D3 were MBR0520L, 1N5817, and an ideal diode, respectively. In the improved cold cathode trigger tube model (II), the gas discharge switch distributed capacitance C was set to 100nF, diodes D1, D2, and D3 were all 1N5817, and the attenuation coefficient r was set to 0.1. Simulation waveforms for various characteristic parameters are shown below. Figures 24-28 As shown.

[0169] A specific implementation scheme of this invention, the working principle of the SPICE design method for cold cathode triggering transistor circuit simulation, can be explained in detail as follows:

[0170] 1. Main clearance channel design (S1):

[0171] In the SPICE simulation environment, the first step is to design the main gap channel. The main gap channel is the main part of the cold cathode trigger tube and determines the basic electrical characteristics of the trigger tube.

[0172] During the design process, the electrical parameters of the main gap, such as breakdown voltage and discharge current, need to be considered. These parameters will directly affect the performance of the trigger tube.

[0173] 2. Trigger gap channel design (S2):

[0174] The trigger gap channel is the channel in the cold cathode trigger tube used to trigger the main gap discharge.

[0175] When designing the trigger gap channel, it is necessary to determine parameters such as trigger voltage and trigger current to ensure that the main gap discharge can be reliably triggered under given conditions.

[0176] 3. Control Module Design (S3):

[0177] The control module is used to control the working status of the main gap and the trigger gap.

[0178] In SPICE simulation, the control module can be programmed to adjust the electrical parameters of the main gap and trigger gap, such as voltage and current, according to the actual needs of the circuit.

[0179] 4. Verification of cold cathode trigger tube characteristic parameters and problem analysis (S4):

[0180] After completing the design of the main gap channel, trigger gap channel, and control module, the characteristic parameters of the cold cathode trigger tube need to be verified.

[0181] Run the circuit model using SPICE simulation software, observe and record the electrical characteristics of the trigger transistor, such as trigger voltage, trigger current, and discharge delay time.

[0182] If the simulation results are found to be inconsistent with expectations or to have problems, the reasons need to be analyzed and appropriate adjustments made.

[0183] 5. Improved SPICE model and characteristic parameter verification of cold cathode trigger tube based on gas discharge theory (S5):

[0184] Based on the gas discharge theory, the SPICE model of the cold cathode trigger tube is improved.

[0185] When improving the model, it is necessary to consider the physical phenomena and electrical characteristics of the gas discharge process, such as gas ionization, electron generation and transport.

[0186] By improving the model, the electrical characteristics of the cold cathode trigger tube can be simulated more accurately.

[0187] The improved model needs to be verified using SPICE simulation software to ensure the accuracy and reliability of the simulation results.

[0188] 6. Simulation and Result Analysis of the Improved Cold Cathode Trigger (S6):

[0189] The improved SPICE model of the cold cathode trigger tube was applied to a real circuit for simulation analysis.

[0190] The operating state of the circuit is simulated using simulation software, and the performance of the trigger transistor in the actual circuit is observed and recorded.

[0191] The simulation results are analyzed to evaluate whether the performance of the trigger tube meets the design requirements, and further optimization and adjustment are made as needed.

[0192] In summary, this SPICE simulation design method for cold cathode trigger transistors provides an effective tool and approach for designing and optimizing cold cathode trigger transistors through detailed steps and principles. The application of SPICE simulation software allows for more accurate simulation and analysis of the electrical characteristics of cold cathode trigger transistors, providing strong support for circuit design and optimization.

[0193] The specific implementation method for SPICE design of cold cathode trigger transistor circuit simulation can be carried out by referring to the following steps:

[0194] I. Preliminary Preparations

[0195] 1. Understand the working principle of cold cathode trigger tubes: Cold cathode trigger tubes utilize the principle of gas discharge and have the characteristics of high reliability and strong environmental adaptability. They are widely used in military, medical, aerospace and scientific research fields.

[0196] 2. Familiarity with SPICE software: SPICE is a circuit-level simulation program developed by the University of California, Berkeley, suitable for nonlinear DC, transient, and linear AC analysis.

[0197] II. Model Design

[0198] 1. Main clearance channel design:

[0199] Based on the working principle of the cold cathode trigger tube, determine the electrical parameters of the main gap, such as breakdown voltage and discharge current.

[0200] In SPICE, the main gap channel is simulated by editing and modifying existing models or creating new models.

[0201] 2. Trigger gap channel design:

[0202] The design of the trigger gap channel needs to ensure that the main gap discharge can be reliably triggered under given conditions.

[0203] Set parameters such as trigger voltage and trigger current, and simulate the trigger gap channel in SPICE.

[0204] 3. Control Module Design:

[0205] The control module is designed to control the working status of the main gap and the trigger gap.

[0206] In SPICE, the functions of the control module, such as adjusting voltage and current, are implemented through programming.

[0207] III. Model Validation and Improvement

[0208] 1. Verification of the characteristic parameters of the cold cathode trigger tube:

[0209] Run the circuit model using SPICE simulation software, observe and record the electrical characteristics of the trigger transistor, such as trigger voltage, trigger current, and discharge delay time.

[0210] Compare the simulation results with the expected values ​​or experimental data to ensure the accuracy of the simulation model.

[0211] 2. Improved model based on gas discharge theory:

[0212] Based on the gas discharge theory, the physical phenomena and electrical characteristics of the cold cathode trigger tube during the discharge process are analyzed.

[0213] Based on the analysis results, the SPICE model was improved to more accurately simulate the electrical characteristics of the cold cathode trigger tube.

[0214] 3. Verification of characteristic parameters again:

[0215] The improved model was used for simulation to verify the electrical characteristics of the trigger tube again.

[0216] To ensure that the improved model can more accurately reflect the performance of the cold cathode trigger tube.

[0217] IV. Application Simulation and Result Analysis

[0218] 1. Apply the improved model to a real circuit:

[0219] The improved SPICE model of the cold cathode trigger tube was embedded into the actual circuit.

[0220] Simulate the circuit's operating state in SPICE, observe and record the performance of the trigger transistor in the actual circuit.

[0221] 2. Results Analysis:

[0222] Analyze the simulation results to evaluate whether the performance of the trigger transistor meets the design requirements.

[0223] If the performance does not meet the requirements, further optimization and adjustments should be made based on the simulation results.

[0224] The above steps demonstrate the specific operation of the SPICE design method for simulating cold cathode trigger transistor circuits. Throughout the process, it is crucial to ensure the accuracy of the model, the reliability of the simulation results, and the rationality of optimization adjustments.

[0225] It should be noted that embodiments of the present invention can be implemented in hardware, software, or a combination of both. The hardware portion can be implemented using dedicated logic; the software portion can be stored in memory and executed by a suitable instruction execution system, such as a microprocessor or dedicated-design hardware. Those skilled in the art will understand that the above-described devices and methods can be implemented using computer-executable instructions and / or included in processor control code, for example, such code provided on a carrier medium such as a disk, CD, or DVD-ROM, a programmable memory such as read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuitry such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field-programmable gate arrays, programmable logic devices, etc., or by software executed by various types of processors, or by a combination of the above-described hardware circuitry and software, such as firmware.

[0226] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cold cathode trigger tube circuit simulation SPICE design method, characterized by, The method comprises: S1: main gap channel design; S2: trigger gap channel design; S3: control module design; S4: cold cathode trigger tube characteristic parameter verification and problem analysis; S5: improving the cold cathode trigger tube SPICE model based on the gas discharge theory and verifying the characteristic parameters; S6: application simulation of the improved cold cathode trigger tube and result analysis; According to the working principle of the cold cathode trigger tube, the electrical parameters of the main gap, such as breakdown voltage and discharge current, are determined, and the main gap channel is simulated in SPICE by editing and modifying the existing model or creating a new model; The design of the trigger gap channel needs to ensure that the main gap discharge can be reliably triggered under given conditions, and the trigger voltage and trigger current parameters are set, and the trigger gap channel is simulated in SPICE; The control module is designed to control the working state of the main gap and the trigger gap, and the function of the control module is realized by programming in SPICE, and the electrical parameters of the main gap and the trigger gap are adjusted according to the actual needs of the circuit; Run the circuit model through the SPICE simulation software, observe and record the electrical characteristics of the trigger tube, such as trigger voltage, trigger current and discharge delay time, and compare the simulation results with the expected values or experimental data. If the simulation results do not match the expectations or there are problems, the reasons need to be analyzed and adjusted accordingly; Based on the principle of gas discharge, a gas discharge switch is constructed, and the main circuit and static breakdown voltage weakening module of the gas discharge switch are added to the cold cathode trigger tube trigger gap channel circuit and the gas discharge switch control module respectively to realize the function of controlling the conduction delay time of the cold cathode trigger tube. The improved model is used for simulation to verify the electrical characteristics of the trigger tube again; The improved cold cathode trigger tube SPICE model is applied to the actual circuit for simulation analysis, the working state of the circuit is simulated in SPICE, the performance of the trigger tube in the actual circuit is observed and recorded, the simulation results are analyzed, and whether the performance of the trigger tube meets the design requirements is evaluated, and further optimization and adjustment are made according to the needs.

2. The cold cathode ignitron circuit simulation SPICE design method of claim 1, wherein, The S1 specifically comprises: Under the trigger condition, when the applied working voltage acts on both ends of the main gap channel, the cold cathode trigger tube as a whole will show a working state or a non-working state according to the size and direction of the applied voltage. In the non-working state, the main gap channel of the cold cathode trigger tube shows an insulation resistance of more than 10MΩ, while the resistance of the main gap channel of the triggered tube decreases to zero point several ohms, which is similar to a short circuit state.

3. The cold cathode ignitron circuit emulation SPICE design method of claim 1, wherein, The S2 specifically comprises: Normally, when the voltage applied to both ends of the main gap channel is lower than the self-breakdown voltage of the trigger tube, the trigger tube does not break down and conduct. At this time, if a trigger pulse with a certain amplitude and width is applied to the trigger electrode, the trigger gap between the trigger electrode and the adjacent electrode breaks down and conducts, and the process of discharge is also the breakdown and conduction of the trigger tube. Due to the interference of external uncertain factors, in order to avoid the mis-conduction of the trigger tube, it is necessary to set the minimum trigger current Tkmin .

4. The cold cathode ignitron circuit simulation SPICE design method of claim 1, wherein, The S3 specifically comprises: (1) Self-breakdown voltage control module The self-breakdown voltage of the cold cathode trigger tube is influenced by many factors such as the type and pressure of the gas in the tube, the gap distance between adjacent electrodes, the electrode material, size, shape and surface condition; a formula for calculating the self-breakdown voltage of the cold cathode trigger tube based on three parameters: ionization constant, adjacent electrode gap distance and gas pressure in the trigger tube: ; wherein: is the gas constant; d is the gap distance between adjacent electrodes in the trigger tube; is the gas pressure in the trigger tube; The output voltages of three different DC voltage sources are used to replace the above three parameters to realize the input of parameters and the calculation of self-breakdown voltage; (2) Working voltage control module The trigger pulse with a certain amplitude and width is added, and the working voltage required is calculated from the general working characteristic curve of the cold cathode trigger tube; (3) Working current limiting module According to the general operating characteristic curve of the cold cathode trigger tube, when the main gap current is less than the maximum operating current opmax the voltage at the node Open makes the voltage-controlled switch S_Open close, the whole main gap channel is closed, and the cold cathode trigger tube can work normally.

5. The cold cathode ignitron circuit emulation SPICE design method of claim 1, wherein, The S4 specifically comprises: (1) Self-breakdown voltage test The measured tube is connected, the DC voltage applied to the main gap is slowly increased within the specified voltage rise time, the main gap is broken down, and the breakdown voltage value is recorded, which is the self-breakdown voltage value of the trigger tube; (2) Minimum trigger voltage test The measured tube is connected, a specified working voltage is applied to the main gap, the trigger voltage is gradually increased, the trigger tube is worked, and the voltage value of the trigger tube DC voltage at this time is recorded, which is the minimum trigger voltage of the trigger tube; (3) Working voltage range test The measured tube is connected, the DC voltage applied to the main gap is gradually increased under the specified trigger condition, the trigger tube is worked, and the DC voltage value is recorded, which is the minimum working voltage of the trigger tube; (4) Working current range test The measured tube is connected, the specified trigger voltage and working voltage are applied, the trigger tube is normally worked, and the maximum working current value is measured.

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