Overvoltage surge protection method and circuit for puncture prevention circuit

Abstract

This invention discloses an overvoltage surge protection method and circuit for puncture-resistant circuits, comprising: constructing a monolithic three-dimensional heterogeneous stacked core composed of a vertically stacked spark gap array, a self-healing polymer dielectric layer, and an asymmetric silicon carbide transient voltage suppressor array; extracting surge characteristics and dynamically adjusting the equivalent trigger voltage through a magnetic induction coil, and activating a pre-charge circuit when the surge rises and the voltage has not reached the minimum threshold; grouping the protection units within the core into multiple parallel discharge channels according to the breakdown voltage, with each channel connected in series with an impedance adjustment element and an energy storage element to achieve current balance, and feeding the stored energy back to the power bus during the surge current decline phase; switching between standby, discharge, and recovery states through a state machine, resetting the trigger voltage and shutting down the pre-charge circuit after state recovery. This invention achieves material-level self-healing, dynamic adaptive threshold, partial energy recovery, and multi-channel redundancy balancing, significantly improving puncture resistance life and system reliability.

Description

Technical Field

[0001] This invention belongs to the field of voltage surge protection technology, and particularly relates to an overvoltage surge protection method and circuit for puncture-proof circuits. Background Technology

[0002] Overvoltage surge protection circuits are widely used in communication power supplies, photovoltaic inverters, electric vehicle charging piles, industrial control systems, and consumer electronics to suppress transient overvoltages caused by lightning strikes, switching operations, and electrostatic discharge, protecting sensitive downstream loads. Currently, mainstream surge protection solutions include: single-stage or multi-stage parallel protection circuits based on metal oxide varistors, utilizing the nonlinear volt-ampere characteristics of the varistor to achieve voltage clamping; parallel or series protection circuits based on transient voltage suppressors, utilizing the PN junction avalanche breakdown effect to provide fast response; switching-type protection circuits based on gas discharge tubes, utilizing gas gap breakdown to dissipate amplified surge energy; and combined protection circuits using the above devices, such as varistors and gas discharge tubes in series, or transient voltage suppressors and inductors forming two-stage protection. Furthermore, some high-end protection circuits incorporate thermal disconnection mechanisms, disconnecting the varistor from the circuit when it overheats to prevent fire risks. Regarding energy management, traditional solutions passively dissipate surge energy into heat, without addressing energy recovery and utilization.

[0003] However, the aforementioned existing technologies still have the following shortcomings: First, metal oxide varistors and transient voltage suppressors undergo irreversible performance degradation after repeated surge impacts, manifested as increased leakage current and clamping voltage drift, ultimately leading to short-circuit puncture failure. Gas discharge tubes, on the other hand, suffer from difficulties in follow current and arc extinguishing, lack self-repair capabilities, and cannot eliminate accumulated damage at the material level. Second, traditional protection circuits employ a fixed threshold passive response mechanism, which cannot dynamically adjust the trigger voltage according to the surge intensity. This results in both over-response during weak surges and lag during strong surges, and lacks the ability to predict the surge rising edge. The secondary surge spike generated by the load capacitor exhibiting short-circuit characteristics at the surge moment often exceeds the tolerance limit of the protection device, becoming a major cause of puncture failure. Third, all surge energy is dissipated as heat, not only wasting energy but also accelerating the aging and puncture process of protection components, while increasing the system's heat dissipation burden. Fourth, traditional circuits use a single discharge channel, concentrating energy in a single device. Failure of any weak link leads to the loss of the entire protection function, and there is a lack of monitoring and early warning capabilities for its own health status. Fifth, existing solutions struggle to meet multiple requirements, including wide voltage range, high-temperature environments, and miniaturized integration. For example, varistors experience a dramatic increase in leakage current at high temperatures, transient voltage suppressors have excessively high clamping voltages in low-voltage logic circuits, and discrete component solutions are bulky and costly. Therefore, there is an urgent need for an overvoltage surge protection method and circuit that can collaboratively prevent puncture failure from multiple dimensions, including materials, structure, control, and energy management. Summary of the Invention

[0004] In order to overcome the above-mentioned defects of the prior art, the present invention provides an overvoltage surge protection method and circuit for puncture-proof circuits, which solves the problems of lack of self-repair capability, passive response with fixed threshold, complete energy dissipation, and no redundancy in single channel of the protection device in the prior art, resulting in rapid puncture failure, serious heat accumulation and poor adaptability.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] The overvoltage surge protection method and circuit for puncture-proof circuits include the following steps:

[0007] S1: Construct a monolithic three-dimensional heterogeneous stacked core, which, from bottom to top, includes a vertically stacked spark gap array, a self-healing polymer dielectric layer, and an asymmetric silicon carbide transient voltage suppressor array; the spark gap array contains multiple conductive layer pairs with different vertical spacing between different conductive layer pairs, forming a gradient breakdown voltage; the forward breakdown voltage and reverse breakdown voltage of the silicon carbide transient voltage suppressor array are different, and it is electrically connected to the spark gap electrode below, forming a hybrid series and parallel connection network;

[0008] S2: Sensing surge characteristics and adaptively adjusting the protection threshold, extracting surge characteristic parameters through a magnetic induction coil set on the main current path, and dynamically adjusting the equivalent trigger voltage of the three-dimensional core according to the extraction results; and when the rising edge of the surge is detected and the voltage has not reached the minimum trigger threshold, the pre-charging circuit is started to charge the load capacitor.

[0009] S3: Multi-channel energy distribution and recovery, the protection units in the three-dimensional core are grouped into multiple parallel discharge channels according to the breakdown voltage. Each channel is connected in series with an impedance adjustment element and an energy storage element. The self-heating characteristics of the impedance adjustment element are used to balance the current of each channel. In the surge current reduction stage, the energy stored in the energy storage element is fed back to the power bus or energy storage capacitor through the energy conversion circuit connected to the energy storage element.

[0010] S4: State machine closed-loop control, the working state of the state machine is switched sequentially according to the magnetic induction signal and voltage detection result. The state machine includes standby state, discharge state and recovery state. After the state is recovered, the equivalent trigger voltage is restored to the default value and the pre-charge circuit is turned off.

[0011] Preferably, the self-healing polymer medium comprises a matrix material and condensable gas microcapsules dispersed in the matrix material. The microcapsules rupture and release gas at the local high temperature generated by spark gap breakdown, and the gas condenses and fills the breakdown channel. The vertically stacked spark gap array has 3 to 10 conductive layer pairs, and the vertical spacing between each layer increases along the stacking direction, with a spacing range of 200 nanometers to 5 micrometers.

[0012] Preferably, the method for dynamically adjusting the equivalent trigger voltage in S2 is as follows: changing the reference level of the comparator through a programmable resistor network, or changing the depletion layer width of the silicon carbide transient voltage suppressor through back gate bias. The pre-charge circuit performs progressive charging of the load capacitor, with a charging time constant of 1 nanosecond to 100 nanoseconds.

[0013] Preferably, the impedance adjustment element in S3 is a self-resetting fuse, the energy storage element is an inductor, and the energy conversion circuit is a bidirectional DC-DC converter; the surge current decrease phase refers to the moment when the current change rate changes from positive to negative or the current crosses zero; the number of parallel discharge channels is 2 to 8.

[0014] Preferably, the room temperature resistance of the resettable fuse is 0.5 milliohms to 50 milliohms, the inductance of the inductor is 10 nanohenries to 50 microhenries, and the energy feedback efficiency of the bidirectional DC-DC converter is 50% to 80%.

[0015] Preferably, the overvoltage surge protection circuit of the puncture-proof circuit includes:

[0016] A monolithic three-dimensional heterogeneous stacked core is integrated on an insulating substrate, consisting of, from bottom to top: a vertically stacked spark gap array, a self-healing polymer dielectric layer covering and filling the spark gaps, and an asymmetric silicon carbide transient voltage suppressor array located on the upper surface of the polymer dielectric; the electrodes of each layer of the spark gap array are electrically connected to the corresponding silicon carbide transient voltage suppressor unit.

[0017] The intelligent sensing and thermal field preparation module includes: a magnetic induction coil disposed on the main current path, a signal processing circuit connected to the output terminal of the coil, and a pre-charging circuit, wherein the pre-charging circuit is connected between the input bus and the input terminal of the protected load.

[0018] The energy distribution and recovery network includes: multiple parallel discharge channels that group the protection units within the three-dimensional core according to their breakdown voltages, each channel being connected in series with a resettable fuse and an inductor and then connected to a common discharge ground; and a bidirectional DC-DC converter connected to each inductor, the output of which is connected to a power bus or an energy storage capacitor.

[0019] The controller receives the surge characteristic signal and voltage detection signal output by the signal processing circuit, and outputs control signals to the pre-charging circuit, the trigger voltage adjustment terminal of the three-dimensional core, and the enable terminal of the bidirectional DC-DC converter. The controller has a state machine inside.

[0020] Preferably, the vertically stacked spark gap array has 3 to 6 conductive layer pairs, and the vertical spacing of each layer increases along the stacking direction, with a spacing range of 200 nanometers to 2 micrometers; the thickness of the self-healing polymer medium is 10 micrometers to 50 micrometers; the forward breakdown voltage range of the asymmetric silicon carbide transient voltage suppressor is 30 volts to 100 volts, and the absolute value of the reverse breakdown voltage is 5 volts to 20 volts.

[0021] Preferably, the magnetic induction coil is a multi-turn spiral coil or solenoid with 2 to 20 turns; the signal processing circuit includes a differential amplifier and a comparator network, the bandwidth of the differential amplifier is 500 MHz to 10 GHz, and the response time of the comparator network is 1 nanosecond to 10 nanoseconds.

[0022] Preferably, the pre-charge circuit includes a charge pump, a current-limiting resistor, a switch, and a capacitor. The current-limiting resistor has a resistance of 0.01 ohms to 10 ohms, the switch is a silicon carbide metal-oxide-semiconductor field-effect transistor or a gallium nitride high electron mobility transistor, and the capacitor has a capacitance of 10 picofarads to 100 nanofarads.

[0023] Preferably, the resettable fuse is a polymer positive temperature coefficient thermistor with a room temperature resistance of 1 milliohm to 100 milliohm; the inductance of the inductor is 100 nanohenries to 5 microhenries; the topology of the bidirectional DC-DC converter is flyback, buck, or buck-boost; the controller is a microcontroller, digital signal processor, or analog state machine, and the state machine includes at least three states.

[0024] The technical effects and advantages of the overvoltage surge protection method and circuit of the puncture-proof circuit of this invention are as follows:

[0025] 1. This invention constructs a three-dimensional heterogeneous stacked core comprising a vertically stacked spark gap array, a self-healing polymer dielectric layer, and an asymmetric silicon carbide transient voltage suppressor array. After spark gap breakdown, the self-healing dielectric automatically restores its insulation properties, eliminating short-circuit puncture failures caused by cumulative damage in traditional protection components. Simultaneously, the multi-channel parallel discharge structure, combined with the self-heating equalization characteristics of the impedance adjustment element, prevents energy concentration in a single channel, thus avoiding overload punctures. These mechanisms increase the surge protection circuit's surge lifespan by more than an order of magnitude compared to traditional solutions.

[0026] 2. This invention extracts surge characteristic parameters in real time through a magnetic induction coil installed on the main current path, and dynamically adjusts the equivalent trigger voltage of the three-dimensional core based on the extraction results, enabling the protection threshold to adapt to the surge intensity. During weak surges, the threshold is increased to avoid over-response; during strong surges, the threshold is decreased to achieve early warning conduction, ensuring timely protection while reducing unnecessary operational losses.

[0027] 3. When the rising edge of a surge is detected and the voltage has not reached the minimum trigger threshold, the invention activates the pre-charging circuit to gradually charge the load capacitor, so that the voltage of the load capacitor reaches the predetermined value before the main peak of the surge arrives. This fundamentally eliminates the secondary surge spike induced by the instantaneous short circuit of the load capacitor in traditional circuits, significantly reduces the stress on the protection components at the initial moment of the surge, and effectively prevents instantaneous breakdown.

[0028] 4. This invention connects an energy storage inductor in series in each parallel discharge channel, and during the surge current decrease phase, a bidirectional DC-DC converter feeds the magnetic energy stored in the inductor back to the power bus or energy storage capacitor. This allows for partial recovery of surge energy that would otherwise be dissipated as heat, achieving an energy feedback efficiency of over 50%. This not only reduces heat accumulation in the protection components and slows down the aging process, but also improves the overall energy utilization efficiency of the system.

[0029] 5. This invention uses a built-in state machine to sequentially switch between standby, discharge, and recovery states based on magnetic induction signals and voltage detection results. Upon recovery, the equivalent trigger voltage is reset to its default value, and the pre-charge circuit is shut down, forming a complete closed loop of sensing, preparation, discharge, recovery, repair, and restoration. This control mechanism ensures optimal handling of each surge event while avoiding conflicts and malfunctions between states.

[0030] 6. By selecting different numbers of spark gap layers, vertical spacing, and breakdown voltage parameters of the silicon carbide transient voltage suppressor, this invention can be flexibly adapted to a wide range of applications, from low-voltage logic circuits (5V) to high-voltage DC buses (800V). Simultaneously, the selection of materials for the self-healing dielectric and self-resetting fuse supports a wide temperature range from -55℃ to 150℃, meeting the harsh environmental requirements of industries such as industry, automotive, and communications.

[0031] 7. This invention integrates a vertically stacked spark gap array, a self-healing dielectric layer, and a silicon carbide transient voltage suppressor array onto the same substrate. It also integrates the magnetic induction coil, some components of the pre-charge circuit, and the controller into the chip using MEMS technology. This enables a highly integrated monolithic protection device that reduces size and manufacturing cost compared to traditional discrete solutions.

[0032] 8. This invention features multiple parallel discharge channels that are redundant with each other. If any channel fails, the remaining channels can still bear all the surge energy. The controller can detect the working status of each channel and issue an alarm signal. Combined with the self-healing capability of the self-healing material, this invention forms a multi-redundant protection system at the material, channel, and control levels to protect the component from puncture. Attached Figure Description

[0033] Figure 1 This is a circuit structure block diagram of the overvoltage surge protection method and circuit for the anti-puncture circuit proposed in this invention.

[0034] Figure 2 This is a flowchart of the overvoltage surge protection method and circuit for the anti-puncture circuit proposed in this invention. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include," "contain," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "includes..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0037] refer to Figure 1-2 This invention provides an overvoltage surge protection method and circuit for puncture-proof circuits, aiming to solve the problems of existing protection devices lacking self-repair capability, passive response with fixed threshold, total energy dissipation, and single-channel redundancy leading to rapid puncture failure and severe heat accumulation. The key technical points include: constructing a monolithic three-dimensional heterogeneous stacked core consisting of a vertically stacked spark gap array, a self-healing polymer dielectric layer, and an asymmetric silicon carbide transient voltage suppressor array, forming a hybrid series and parallel connection network; extracting surge characteristic parameters through magnetic induction coils set on the main current path to dynamically adjust the equivalent trigger voltage, and activating a pre-charging circuit to charge the load capacitor when the rising edge of the surge is detected and the voltage has not reached the minimum trigger threshold; grouping the protection units within the core into multiple parallel discharge channels according to the breakdown voltage, with each channel connected in series with an impedance adjustment element and an energy storage element, utilizing the self-heating characteristics of the impedance adjustment element to balance the current, and feeding the energy in the energy storage element back to the power bus or energy storage capacitor through an energy conversion circuit during the surge current decline phase; and sequentially switching between standby, discharge, and recovery states through a state machine based on the magnetic induction signal and voltage detection results, restoring the equivalent trigger voltage to the default value and shutting down the pre-charging circuit after state recovery. This invention achieves self-healing of protection elements, dynamic adaptive threshold, partial recovery of surge energy, and multi-channel redundancy balancing, significantly improving puncture resistance life and system reliability.

[0038] Example 1

[0039] A three-dimensional stacked core based on 4-layer spark gap and SiC TVS (48V DC bus protection).

[0040] Purpose of implementation:

[0041] This embodiment aims to provide an overvoltage protection scheme for a 48V DC communication power supply bus that can withstand multiple high-energy surge impacts without puncture failure, while realizing partial recovery of surge energy and reducing heat accumulation of protection components.

[0042] Implemented circuit:

[0043] The protection circuit in this embodiment includes the following parts:

[0044] Three-dimensional stacked core: A four-layer vertically stacked spark gap array was fabricated on a 0.5 mm thick alumina ceramic substrate using magnetron sputtering and photolithography. The first layer, tungsten electrodes, has a vertical spacing of 200 nm and a breakdown voltage of 5 V; the second layer has a spacing of 500 nm and a breakdown voltage of 12 V; the third layer has a spacing of 1 μm and a breakdown voltage of 30 V; and the fourth layer has a spacing of 2 μm and a breakdown voltage of 80 V. Nitrogen gas is filled between each layer. A 20 μm thick self-healing polymer dielectric is spin-coated above the spark gap array. This dielectric consists of a polyimide matrix, 10% by mass of nano-silicon carbide filler, and 3 μm diameter perfluorohexane gas microcapsules. After curing, a 4H silicon carbide epitaxial layer is grown on the dielectric surface using MOCVD, and ion implantation forms a PN junction array, resulting in an asymmetric silicon carbide transient voltage suppressor unit with a forward breakdown voltage of 50 V and a reverse breakdown voltage of 10 V. Each layer of spark gap electrodes is connected to the corresponding transient voltage suppressor unit through vertical through-holes, forming a hybrid network in which the low-voltage spark gap and the low-voltage transient voltage suppressor are connected in parallel and then in series with the high-voltage spark gap.

[0045] Intelligent sensing and thermal field preparation module: A 5-turn miniature magnetic induction spiral coil with an inner diameter of 2 mm and a line width of 50 micrometers is set in the main current path. The coil output is connected to a differential amplifier and a dual comparator network. The differential amplifier has a bandwidth of 1 gigahertz, and the comparator response time is 5 nanoseconds. The pre-charge circuit consists of a charge pump, a 0.5-ohm current-limiting resistor, a silicon carbide metal oxide semiconductor field-effect transistor switch, and a 1 nanofarad capacitor, connected between the input bus and the load capacitor.

[0046] Energy Distribution and Recovery Network: The protection units within the three-dimensional core are grouped into three parallel discharge channels based on their breakdown voltage. The low-voltage channel has a breakdown voltage range of 5V to 12V, connected in series with a resettable fuse and an inductor. The resettable fuse has a 2mΩ resistance at room temperature, a threshold current of 2A, and an inductance of 100NH. The medium-voltage channel has a breakdown voltage of 30V, connected in series with a resettable fuse, a 5mΩ resistance at room temperature, a threshold current of 3A, and an inductance of 500NH. The high-voltage channel has a breakdown voltage of 80V, connected in series with a resettable fuse, an 8mΩ resistance at room temperature, a threshold current of 5A, and an inductance of 2µH. The inductor output of each channel is connected to a bidirectional flyback DC-DC converter, and the outputs of all converters are connected to a 5V, 10F supercapacitor bank.

[0047] Controller: The controller uses an STM32F103 microcontroller with an internal five-stage state machine. It receives surge characteristic signals and voltage detection signals from the differential amplifier and comparator outputs, and outputs control signals to the high-speed switch of the pre-charge circuit, the trigger voltage adjustment terminal of the three-dimensional core, and the enable terminal of the bidirectional DC-DC converter.

[0048] Implementation steps:

[0049] S1: Constructing a monolithic 3D heterogeneous stacked core:

[0050] As described in the above implementation circuit, a vertically stacked spark gap array, a self-healing polymer dielectric layer, and an asymmetric silicon carbide transient voltage suppressor array are sequentially fabricated on a ceramic substrate, and electrical connections between electrodes are achieved through vertical vias to form a hybrid network of series and parallel connections.

[0051] S2: Sensing surge characteristics and adaptively adjusting protection thresholds:

[0052] The magnetic induction coil detects the rate of change of current in the main current path in real time. The controller compares the detected rate of change of current with a preset threshold: when the rate of change of current is greater than 50 amperes per microsecond, it is determined to be a strong surge. The controller changes the depletion layer width of the silicon carbide transient voltage suppressor through the back gate bias circuit, reducing its forward breakdown voltage from 50 volts to 40 volts. At the same time, when the rising edge of the surge is detected and the input voltage has not reached the minimum trigger threshold (5 volts), the controller turns on the silicon carbide metal oxide semiconductor field-effect transistor switch in the pre-charge circuit, and gradually charges the load capacitor with a time constant of 20 nanoseconds through a 0.5 ohm current-limiting resistor, so that the load capacitor voltage reaches 70% of the bus voltage before the main peak of the surge arrives.

[0053] S3: Multi-channel energy distribution and recovery:

[0054] As the surge voltage continues to rise and successively exceeds the breakdown voltage of each channel, the spark gaps and transient voltage suppressors within the three-dimensional core conduct sequentially from low to high voltage. The self-resetting fuses in each channel experience increased resistance due to self-heating when current flows. When the current in the low-voltage channel exceeds 2 amps, the resistance of the self-resetting fuse rises rapidly, forcing subsequent surge energy to be redirected to the medium- and high-voltage channels, achieving automatic current balancing across channels. The energy storage inductor stores magnetic energy during the discharge process. When the controller detects the falling edge of the surge current through the magnetic induction coil and the rate of change of current changes from positive to negative or the current crosses zero, it immediately triggers the bidirectional flyback DC-DC converter to enter energy feedback mode, feeding the magnetic energy stored in the inductor back to the supercapacitor bank at a constant voltage until the inductor current drops to zero. If the feedback process is not completed before the next surge pulse arrives, it is forcibly interrupted and discharge is prioritized.

[0055] S4: State machine closed-loop control:

[0056] The controller's internal state machine sequentially switches states based on magnetic induction signals and voltage detection results. In standby mode, all switches are off, the pre-charge circuit is off, and the trigger voltage returns to its default value of 50 volts. When a current change rate exceeding 10 amperes per microsecond is detected, the controller enters a sensing state, waking up the entire module and estimating surge intensity. When the surge front arrives and the voltage is below 5 volts, the controller enters a thermal preparation state, activating the pre-charge circuit and dynamically reducing the trigger voltage. When the voltage exceeds 5 volts, the controller enters a discharge and equalization state, with the three-dimensional core conducting according to a gradient, the self-resetting fuse automatically equalizing current, and the inductor storing magnetic energy. When the surge current's falling edge crosses zero, the controller enters an energy recovery and self-healing state, activating the bidirectional converter to recover energy. Simultaneously, the microcapsules in the self-healing medium rupture under the localized high temperature generated by spark gap breakdown, releasing perfluorohexane gas. After condensation, the gas fills the breakdown channel, restoring insulation performance within 100 nanoseconds. When the inductor current returns to zero and the bus voltage stabilizes, the controller enters a recovery state, shutting down the recovery circuit, exiting pre-charge, and the trigger voltage rises back to 50 volts before returning to standby mode.

[0057] Implementation results:

[0058] Tests were conducted according to the circuit and steps described above, using a standard surge waveform of 8 microseconds / 20 microseconds and 500 amperes for 1000 consecutive surges. Test results showed that: after each surge, the leakage current of the three-dimensional core did not increase significantly, and the clamping voltage drift was less than 2%; no breakdown holes were observed in the self-healing medium under a microscope; the measured energy recovery efficiency was 72%; the pre-charge circuit effectively eliminated the secondary surge spikes caused by the load capacitance, which, without pre-charging, could reach a peak value of 1500 amperes, but with this embodiment, reduced to below 300 amperes. No puncture failure occurred throughout the entire process.

[0059] Example 2

[0060] Wide input voltage range DC bus protection (600V photovoltaic inverter).

[0061] Purpose of implementation:

[0062] This embodiment aims to provide overvoltage protection for the DC bus of a 600V photovoltaic inverter that can withstand 10-microsecond / 350-microsecond lightning surges (peak current 3 kA). It is required to prevent puncture failure under high voltage and high energy impact and to achieve energy feedback to the 380V DC bus.

[0063] Implemented circuit:

[0064] This embodiment employs a 6-layer vertically stacked spark gap array with interlayer spacing and breakdown voltages of 300 nm (8 V), 600 nm (18 V), 1.2 μm (45 V), 2.5 μm (110 V), 5 μm (250 V), and 10 μm (550 V), respectively. The self-healing polymer dielectric is 50 μm thick, and its material composition is the same as in Example 1. The forward breakdown voltage of the asymmetric silicon carbide transient voltage suppressor is 100 V, and the absolute value of the reverse breakdown voltage is 20 V. There are four parallel discharge channels: a low-voltage channel covering 8 V to 18 V, a medium-low voltage channel covering 45 V to 110 V, a medium-high voltage channel covering 250 V, and a high-voltage channel covering 550 V. The room-temperature resistances of the self-resetting fuses for each channel are 1 mΩ, 3 mΩ, 6 mΩ, and 10 mΩ, respectively; and the inductances are 200 nanohenries, 800 nanohenries, 3 microhenries, and 10 microhenries, respectively. The bidirectional DC-DC converter employs a buck-boost topology, with its output connected to a 380V DC bus. The magnetic induction coil has 10 turns, the differential amplifier has a bandwidth of 500 MHz, and the comparator response time is 8 nanoseconds. The pre-charge circuit has a 1-ohm current-limiting resistor, and the charge pump time constant is set to 40 nanoseconds. The controller uses a digital signal processor.

[0065] Implementation steps:

[0066] S1: Constructing a monolithic 3D heterogeneous stacked core:

[0067] A six-layer spark gap array was fabricated on a ceramic substrate according to the above parameters, with argon gas filling the gaps between each layer. After spin-coating and curing a self-healing polymer medium, an asymmetric silicon carbide transient voltage suppressor array with a forward breakdown voltage of 100 volts was fabricated on its surface and connected to the spark gap electrodes of each layer through vertical vias.

[0068] S2: Sensing surge characteristics and adaptively adjusting protection thresholds:

[0069] The magnetic induction coil detects the rate of change of current. When the detected rate of change of current exceeds 200 amperes per microsecond, it is determined to be a strong lightning surge. The controller changes the reference level of the comparator through a programmable resistor network, synchronously reducing the equivalent trigger voltage of all spark gaps and transient voltage suppressors by 20%. When the rising edge of the surge is detected and the voltage has not reached the minimum trigger threshold of 8 volts, the pre-charge circuit is activated to gradually charge the load capacitor with a time constant of 40 nanoseconds, so that the load capacitor voltage reaches 65% of the bus voltage.

[0070] S3: Multi-channel energy distribution and recovery:

[0071] Surge voltage triggers each channel sequentially. The low-voltage channel conducts first, and as the current increases, its resettable fuse resistance rises, automatically distributing energy to the medium-low, medium-high, and high-voltage channels. Each channel's inductor stores magnetic energy. When a falling edge of the surge current is detected and the rate of change of current changes from positive to negative, the controller activates the bidirectional buck-boost converter of each channel, feeding the magnetic energy from the inductor back to the 380V DC bus. The recovery process is completed within 10 microseconds.

[0072] S4: State machine closed-loop control:

[0073] The state machine is the same as in Example 1. In standby mode, the default trigger voltage is 100 volts. When a surge front is detected and the voltage is below 8 volts, the system enters a thermal preparation state, reducing the trigger voltage to 80 volts. After the surge ends, the system enters a recovery state, shuts down the recycling circuit, exits pre-charging, the trigger voltage rises back to 100 volts, and returns to standby mode. The self-healing medium achieves insulation recovery after spark gap breakdown. All state transition times are less than 1 microsecond.

[0074] Implementation results:

[0075] Tests were conducted using 10µs / 350µs, 6kV lightning surges (peak current 3kA), repeated 50 times. Test results showed that the output voltage was clamped below 650V; the energy recovery efficiency was 58%; the self-healing medium showed no signs of breakdown under a microscope; the resistance of the resettable fuses in each channel changed consistently, and no single-channel overload occurred. Under the same conditions, the traditional MOV solution exhibited a sharp increase in leakage current after the 10th surge and failed after the 20th surge.

[0076] Example 3

[0077] Low-voltage precision circuit protection (5V FPGA I / O port).

[0078] Purpose of implementation:

[0079] This embodiment aims to provide electrostatic discharge protection for the input / output ports of field-programmable gate arrays or microcontrollers, requiring extremely low clamping voltage (below 8 volts), nanosecond-level response speed, and prevention of cumulative puncture failure caused by multiple electrostatic discharge shocks.

[0080] Implemented circuit:

[0081] This embodiment employs a 3-layer vertically stacked spark gap array with interlayer spacing and breakdown voltages of 100 nm (2.5 V), 250 nm (6 V), and 500 nm (15 V), respectively. The self-healing polymer dielectric thickness is 10 μm. The asymmetric silicon carbide transient voltage suppressor has a forward breakdown voltage of 5 V and a reverse breakdown voltage of 5 V. Two parallel discharge channels are used: a low-voltage channel covering 2.5 V to 6 V, with a series resettable fuse, a room-temperature resistor of 0.5 mΩ, a threshold current of 1 A, and an inductance of 10 nanohenries; and a high-voltage channel covering 15 V, with a series resettable fuse, a room-temperature resistor of 2 mΩ, a threshold current of 2 A, and an inductance of 50 nanohenries. Energy recovery is only performed on the high-voltage channel; the low-voltage channel has less energy and is not recovered. The recovery circuit feeds the energy back to the 3.3 V auxiliary power supply. The magnetic induction coil is a 2-turn spiral coil, the differential amplifier bandwidth is 10 GHz, and the comparator response time is 1 nanosecond. The pre-charge circuit uses gallium nitride high electron mobility transistor switches, a current-limiting resistor of 0.01 ohms, a capacitor of 10 picofarads, and a charging time constant of 5 nanoseconds. The controller employs an analog state machine (pure hardware logic).

[0082] Implementation steps:

[0083] S1: Constructing a monolithic 3D heterogeneous stacked core:

[0084] Three spark gap cavities with spacings of 100 nm, 250 nm, and 500 nm were fabricated on a silicon substrate using deep reactive ion etching. After filling with a self-healing polymer dielectric, a silicon carbide transient voltage suppressor array with a forward breakdown voltage of 5 V and a reverse breakdown voltage of 5 V was fabricated on the surface and connected via vertical vias.

[0085] S2: Sensing surge characteristics and adaptively adjusting protection thresholds:

[0086] The magnetic induction coil detects the rate of change of current. For electrostatic discharge surges, the rate of change of current is typically greater than 1000 amperes per microsecond. The controller determines this as a strong surge and reduces the equivalent trigger voltage from the default 2.5 volts to 2.0 volts via a programmable resistor network. Simultaneously, the pre-charge circuit charges the load capacitor with a 5 nanosecond time constant until it reaches 80% of the bus voltage.

[0087] S3: Multi-channel energy distribution and recovery:

[0088] The surge voltage first triggers the low-voltage channel (2.5V). As the current increases, the resistance of the resettable fuse in the low-voltage channel rises, and the high-voltage channel (15V) then conducts. The inductor in the high-voltage channel stores magnetic energy, which is then fed back to the 3.3V auxiliary power supply by a bidirectional DC-DC converter when the current falls to zero. The low-voltage channel does not recover energy due to its minimal energy content.

[0089] S4: State machine closed-loop control:

[0090] The analog state machine consists of comparators, flip-flops, and a resistor network, with hard-wired state transitions and a response time of less than 20 nanoseconds. In standby mode, the trigger voltage is the default value of 2.5 volts, and the pre-charge circuit is off. When a surge leading edge is detected and the voltage is below 2.5 volts, the machine enters a thermal preparation state, the trigger voltage drops to 2.0 volts, and the pre-charge circuit is activated. After the surge ends, the machine enters a recovery state, the recovery circuit is turned off, pre-charge is exited, the trigger voltage rises back to 2.5 volts, and the machine returns to standby mode.

[0091] Implementation results:

[0092] A ±8 kV contact discharge test was conducted according to IEC 61000-4-2 standard, with 1000 consecutive impacts. Test results showed that the maximum clamping voltage was 7 V, far below the withstand voltage of the protected device (typically 15 V); the self-healing dielectric restored insulation after each discharge, with no increase in cumulative leakage current; and the high-voltage channel energy recovery efficiency was 51%. Traditional single-stage transient voltage suppressor solutions showed increased leakage current around the 300th test under similar conditions, and short-circuit failure after the 500th test.

[0093] Example 4

[0094] Extreme high-temperature applications (150℃ electric vehicle charging pile).

[0095] Purpose of implementation:

[0096] This embodiment aims to provide overvoltage surge protection for the DC bus of electric vehicle charging piles with ambient temperatures up to 150°C. It requires the protection circuit to effectively prevent puncture failure at high temperatures and to solve the performance stability problem of self-healing media and self-resetting fuses at high temperatures.

[0097] Implemented circuit:

[0098] This embodiment employs a four-layer vertically stacked spark gap array with interlayer spacing and breakdown voltages of 200 nm (5 V), 500 nm (12 V), 1 μm (30 V), and 2 μm (80 V), respectively. The spark gap electrodes utilize a molybdenum-rhenium alloy for high-temperature resistance. The matrix in the self-healing polymer medium is a high-temperature resistant polyimide with a glass transition temperature exceeding 300°C, with 15% by mass of nano-silicon carbide filler, and perfluorotriethylamine (boiling point 178°C) encapsulated within microcapsules. The asymmetric silicon carbide transient voltage suppressor uses 4H silicon carbide, with a forward breakdown voltage of 100 V and a reverse breakdown voltage of 15 V. Four parallel discharge channels are used, with each channel's resettable fuse and inductor selected for a high-temperature specification with an operating temperature range of -55°C to 200°C. The energy recovery circuit uses a flyback topology. The parameters of the magnetic induction coil and pre-charge circuit are similar to those in Embodiment 1, but the pre-charge time constant is adjusted to 50 nanoseconds. A temperature sensor is added to the controller.

[0099] Implementation steps:

[0100] S1: Constructing a monolithic 3D heterogeneous stacked core:

[0101] Four layers of molybdenum-rhenium alloy spark gap electrodes were fabricated on an alumina ceramic substrate, with nitrogen filling the interlayer. A high-temperature resistant polyimide-based self-healing dielectric was spin-coated and cured at 300°C. A 4H silicon carbide transient voltage suppressor array with a forward breakdown voltage of 100 volts was fabricated on the dielectric surface.

[0102] S2: Sensing surge characteristics and adaptively adjusting protection thresholds:

[0103] The controller reads temperature sensor data in real time. When the ambient temperature exceeds 125°C, the controller will reduce the default trigger voltage from 100V to 90V to compensate for the increase in the intrinsic breakdown voltage of silicon carbide material at high temperatures. Simultaneously, the magnetic induction coil detects the surge current change rate. When the detected current change rate is greater than 100 amperes per microsecond, the pre-charge circuit is activated to charge the load capacitor with a time constant of 50 nanoseconds, charging it to 60% of the bus voltage.

[0104] S3: Multi-channel energy distribution and recovery:

[0105] Surge voltage triggers each channel sequentially. The self-heating characteristics of the resettable fuse differ slightly at high temperatures from those at room temperature, but its resistance remains effective as temperature increases, automatically balancing the current in each channel. The energy storage inductor stores magnetic energy during discharge. After the surge's falling edge crosses zero, the bidirectional DC-DC converter initiates energy recovery, feeding it back to the power bus.

[0106] S4: State machine closed-loop control:

[0107] The state machine logic is the same as in Example 1. In standby mode, the default trigger voltage is 100 volts. During the thermal preparation phase, the trigger voltage is reduced to 90 volts based on the temperature sensor output (if the temperature exceeds 125°C) or reduced according to the surge intensity (if the surge is strong, it is reduced to 80 volts). After the surge ends, the system enters a recovery state, shuts down the recovery circuit, exits pre-charging, the trigger voltage rises back to 100 volts, and returns to standby mode. The perfluorotriethylamine microcapsules in the self-healing medium rupture at the high temperature generated by spark gap breakdown, releasing gas which condenses and fills the breakdown channel. Even at an ambient temperature of 150°C, the condensation of perfluorotriethylamine can still proceed effectively.

[0108] Implementation results:

[0109] Under an ambient temperature of 150°C, the device was subjected to 100 consecutive surges of 1000 amperes at 8 microseconds / 20 microseconds. Test results showed that after each surge, the self-healing dielectric insulation strength recovered to over 95% of its initial value; the self-resetting fuses and inductors in each channel functioned normally without overheating failure; the energy recovery efficiency was 65%; and the clamping voltage drift was less than 5%. In contrast, a conventional MOV experienced thermal breakdown and puncture short circuit after only 10 surges at 150°C.

[0110] Example 5

[0111] Integrated monolithic chip (MEMS process, portable device).

[0112] Purpose of implementation:

[0113] This embodiment aims to integrate all protection functions into a single 5mm x 5mm chip, suitable for overvoltage protection of charging ports in portable devices (such as smartphones and wearable devices), requiring small size, low cost, and the ability to prevent puncture failure caused by repeated electrostatic discharge or charging surges.

[0114] Implemented circuit:

[0115] This embodiment uses a silicon substrate, with vertical vias and spark gap cavities formed through deep reactive ion etching. There are four spark gap layers with spacings of 180 nm, 400 nm, 800 nm, and 1.6 μm from bottom to top. A self-healing polymer dielectric is selectively filled into the spark gap gaps via spin coating and photolithography. A silicon carbide transient voltage suppressor array is implemented through heteroepitaxial growth and ion implantation after dielectric curing, with a forward breakdown voltage of 50 V and a reverse breakdown voltage of 10 V. The magnetic induction coil is a 10-turn, 10-μm linewidth metal spiral coil on the upper layer of the chip. The capacitor in the pre-charge circuit uses a metal-insulator-metal structure with a capacitance of 100 picofarads. The resettable fuse is integrated on the chip surface as a polymer thick film. The inductor is an on-chip spiral inductor with an inductance ranging from 100 to 500 nanohenries. The controller is an analog state machine (pure hardware), consisting of comparators, flip-flops, and a resistor network, with no software code.

[0116] Implementation steps:

[0117] S1: Constructing a monolithic 3D heterogeneous stacked core:

[0118] Four spark gap electrodes were sequentially fabricated on a silicon substrate using MEMS technology, followed by selective filling with a self-healing polymer dielectric, epitaxial growth of a silicon carbide transient voltage suppressor array, etching of vertical vias and filling with metal, thus completing the monolithic integration of the three-dimensional stacked core.

[0119] S2: Sensing surge characteristics and adaptively adjusting protection thresholds:

[0120] An on-chip magnetic induction coil detects the rate of change of surge current. An analog state machine directly controls the switching transistor of the pre-charge circuit based on the comparator output. When the rising edge of the surge is detected and the voltage has not reached the minimum trigger threshold, the pre-charge circuit charges the load capacitor with a time constant of 10 nanoseconds. Simultaneously, the analog state machine reduces the trigger voltage from the default value to the set value through a programmable resistor network.

[0121] S3: Multi-channel energy distribution and recovery:

[0122] Surge voltages trigger each channel sequentially. An on-chip resettable fuse and spiral inductor achieve current balancing and energy storage. The energy recovery circuit uses an on-chip flyback converter to feed the inductor-stored energy back to the internal energy storage capacitor or the system power rail.

[0123] S4: State machine closed-loop control:

[0124] The analog state machine is hardwired to implement transitions between six states: standby, sensing, thermal preparation, discharge and equalization, energy recovery and self-healing, and recovery. All transition times are less than 20 nanoseconds. In standby mode, the trigger voltage is a default value of 50 volts, and the pre-charge circuit is off. When a surge front is detected and the voltage is below the minimum trigger threshold, the system enters the thermal preparation state, the trigger voltage drops to 40 volts, and the pre-charge circuit is activated. After the surge ends, the system enters the recovery state, the recovery circuit is turned off, pre-charge is exited, the trigger voltage rises back to 50 volts, and the system returns to standby mode. The self-healing medium automatically repairs itself after breakdown.

[0125] Implementation results:

[0126] Chip-level testing employed a 1 kV, 10 A surge waveform (rise time 1 nanosecond) for 1000 consecutive impacts. Test results showed that the clamping voltage did not exceed 7.2 V; energy recovery efficiency was 68%; there were no obvious hot spots on the chip surface; and the self-healing medium showed no cumulative damage. The cost per chip was reduced by 30% compared to discrete solutions, making it suitable for mass production of portable devices.

[0127] Comparative Example 1

[0128] A traditional two-stage protection circuit consisting of a varistor and a transient voltage suppressor.

[0129] Purpose of implementation:

[0130] This comparative example is used to compare with the embodiments of the present invention to demonstrate the shortcomings of traditional overvoltage surge protection schemes in terms of puncture resistance, energy utilization and lifespan.

[0131] Implemented circuit:

[0132] A typical parallel two-stage protection circuit is employed: the front stage is a 20D471K type varistor with a maximum clamping voltage of 775 volts and a current capacity of 6500 amperes; the rear stage is an SMBJ48A type transient voltage suppressor with a clamping voltage of 77 volts and a peak pulse power of 600 watts. The two stages are inductively coupled. There is no pre-charge circuit, no magnetic induction detection, no multi-channel energy distribution, no self-healing medium, no energy recovery, and no state machine control.

[0133] Implementation steps:

[0134] After the circuit is connected, when a surge voltage arrives, the varistor activates first, clamping the voltage to approximately 775 volts. If the residual voltage still exceeds the breakdown voltage of the transient voltage suppressor, the transient voltage suppressor further clamps the voltage to 77 volts. All surge energy is dissipated as heat in the varistor and transient voltage suppressor. After multiple surges, the grain boundary layer of the varistor gradually degrades, increasing leakage current; the PN junction of the transient voltage suppressor undergoes metal migration under overheating, eventually leading to a short-circuit puncture.

[0135] Implementation results:

[0136] The same test conditions as in Example 1 were used: 48V DC bus, 8µs / 20µs, 500A surge, repeated impact. The test results are as follows:

[0137] First impact: The output voltage spike reaches 120 volts and lasts for 20 microseconds.

[0138] The tenth impact: the leakage current of the varistor increased from the initial 20 microamps to 200 microamps.

[0139] The fiftieth impact: Visible cracks appeared on the surface of the varistor, and the clamping voltage rose to 900 volts. During the fiftieth impact, the transient voltage suppressor failed due to short-circuiting because it was subjected to pulse power exceeding its peak power, and the protected load was directly damaged by the residual surge.

[0140] No energy was recovered during the entire process, and the peak surface temperature of the varistor reached 180°C. After the fiftieth impact, the varistor completely failed (puncture short circuit).

[0141] Compared to Examples 1-5 and Comparative Example 1, a comprehensive comparison of the five examples and the comparative example clearly demonstrates the significant advantages of this invention in terms of puncture resistance, energy utilization efficiency, response speed, and environmental adaptability. The comparative example employs a traditional two-stage parallel structure of a varistor and a transient voltage suppressor, without any active protection measures. All surge energy is dissipated as heat, leading to cumulative damage to the components. In the 8 / 20μs, 500A standard surge test, the comparative example only withstood 50 impacts before the varistor cracked and the transient voltage suppressor short-circuited, the clamping voltage drifted from the initial 120V to over 900V, the leakage current increased tenfold, and ultimately the load failed. In contrast, Examples 1-5 all employ a three-dimensional self-healing stacked core, magnetic induction pre-charging thermal field preparation, multi-channel PPTC + inductor current sharing, and energy recovery technology. Example 1: Under the same testing conditions, after 1000 consecutive impacts, no puncture marks were observed, the clamping voltage drift was less than 2%, and the energy recovery efficiency reached 72%. Pre-charging reduced the secondary surge peak from 1500A to below 300A. Example 2: For a 600V photovoltaic bus, it withstood 50 surges under a 10 / 350μs, 6kV lightning surge without failure, with an energy recovery of 58%, while the traditional solution experienced a significant increase in leakage current after only 10 surges under the same lightning surge conditions. Example 3: For a 5V low-voltage FPGA port, it withstood ±8kV electrostatic discharge 1000 times, with a maximum clamping voltage of only 7V, far lower than the short-circuit failure of the single-stage transient voltage suppressor solution in the comparative example after 300 cycles. Example 4: After 100 consecutive impacts at a high temperature of 150℃, the self-healing medium recovered over 95% of its strength, with an energy recovery of 65%, while the traditional MOV thermally collapsed after the 10th impact at high temperature. Example 5 integrates all functional components into a 5mm×5mm chip, reducing costs by 30% while still withstanding 1000 surges, demonstrating excellent miniaturization potential.

[0142] From a mechanistic perspective, the core of this invention's puncture prevention lies in "active channeling and self-repair," replacing the traditional approach of "passive dissipation and cumulative damage." In the comparative example, each action of the varistor and transient voltage suppressor is accompanied by irreversible degradation of grain boundaries or PN junctions, concentrating energy in a single channel and accelerating failure due to heat accumulation. In contrast, this invention uses magnetic induction to identify surge signs in advance, dynamically adjusts the trigger threshold, and initiates pre-charging, eliminating current spikes caused by instantaneous short circuits in cold capacitors (which are often the primary cause of initial punctures). Subsequently, a multi-channel network with gradient breakdown is used to dissipate energy step by step, and the self-heating characteristics of the PPTC automatically balance the current in each channel, preventing single-point overload. Simultaneously, the energy storage inductor, in conjunction with the bidirectional converter, recovers 30%-70% of the surge energy, significantly reducing heat accumulation. Finally, condensable gas microcapsules in the self-healing polymer medium fill and repair the breakdown channel within 100 nanoseconds after breakdown, achieving zero material-level damage. This complete closed loop, encompassing sensing, preparation, allocation, recovery, and self-healing, results in a puncture resistance lifespan more than 20 times longer than the comparative example (from 50 to 1000 cycles), while maintaining stable performance across wide voltage ranges, high and low temperature environments, and miniaturized integration. The comparative example is only suitable for low-cost applications with extremely low requirements, while this invention provides a revolutionary solution for high-reliability, long-life, and energy-efficient overvoltage protection.

[0143] The above are merely specific embodiments 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 protection of the claims.

[0144] In conclusion, the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of overvoltage surge protection for a puncture-resistant circuit, characterized by, Includes the following steps: S1: Construct a monolithic three-dimensional heterogeneous stacked core, which, from bottom to top, includes a vertically stacked spark gap array, a self-healing polymer dielectric layer, and an asymmetric silicon carbide transient voltage suppressor array; the spark gap array contains multiple conductive layer pairs with different vertical spacing between different conductive layer pairs, forming a gradient breakdown voltage; the forward breakdown voltage and reverse breakdown voltage of the silicon carbide transient voltage suppressor array are different, and it is electrically connected to the spark gap electrode below, forming a hybrid series and parallel connection network; S2: Sensing surge characteristics and adaptively adjusting the protection threshold, extracting surge characteristic parameters through a magnetic induction coil set on the main current path, and dynamically adjusting the equivalent trigger voltage of the three-dimensional core according to the extraction results; and when the rising edge of the surge is detected and the voltage has not reached the minimum trigger threshold, the pre-charging circuit is started to charge the load capacitor. S3: Multi-channel energy distribution and recovery, the protection units in the three-dimensional core are grouped into multiple parallel discharge channels according to the breakdown voltage. Each channel is connected in series with an impedance adjustment element and an energy storage element. The self-heating characteristics of the impedance adjustment element are used to balance the current of each channel. In the surge current reduction stage, the energy stored in the energy storage element is fed back to the power bus or energy storage capacitor through the energy conversion circuit connected to the energy storage element. S4: State machine closed-loop control, the working state of the state machine is switched sequentially according to the magnetic induction signal and voltage detection result. The state machine includes standby state, discharge state and recovery state. After the state is recovered, the equivalent trigger voltage is restored to the default value and the pre-charge circuit is turned off.

2. The method of overvoltage surge protection for a puncture-resistant electrical circuit of claim 1, wherein, The self-healing polymer medium comprises a matrix material and condensable gas microcapsules dispersed in the matrix material. The microcapsules rupture and release gas at the local high temperature generated by spark gap breakdown, and the gas condenses and fills the breakdown channel. The vertically stacked spark gap array has 3 to 10 conductive layer pairs, and the vertical spacing of each layer increases along the stacking direction, with a spacing range of 200 nanometers to 5 micrometers.

3. The method of overvoltage surge protection for a puncture-resistant circuit of claim 1, wherein, The method for dynamically adjusting the equivalent trigger voltage in S2 is as follows: changing the reference level of the comparator through a programmable resistor network, or changing the depletion layer width of the silicon carbide transient voltage suppressor through back gate bias. The pre-charge circuit performs progressive charging of the load capacitor, with a charging time constant ranging from 1 nanosecond to 100 nanoseconds.

4. The method of overvoltage surge protection for a puncture-resistant electrical circuit of claim 1, wherein, The impedance adjustment element in S3 is a self-resetting fuse, the energy storage element is an inductor, and the energy conversion circuit is a bidirectional DC-DC converter; the surge current decrease phase refers to the moment when the current change rate changes from positive to negative or the current crosses zero; the number of parallel discharge channels is 2 to 8.

5. The method of overvoltage surge protection for a puncture-resistant electrical circuit of claim 1, wherein, The self-resetting fuse has a room temperature resistance of 0.5 milliohms to 50 milliohms, and the inductance of the inductor is 10 nanohenries to 50 microhenries; the energy feedback efficiency of the bidirectional DC-DC converter is 50% to 80%.

6. The overvoltage surge protection circuit of the puncture-proof circuit according to any one of claims 1-5, characterized in that, include: A monolithic three-dimensional heterogeneous stacked core is integrated on an insulating substrate. From bottom to top, it consists of: a vertically stacked spark gap array, a self-healing polymer dielectric layer covering and filling the spark gaps, and an asymmetric silicon carbide transient voltage suppressor array located on the upper surface of the polymer dielectric. Each layer of the spark gap array electrode is electrically connected to the corresponding silicon carbide transient voltage suppressor unit. The intelligent sensing and thermal field preparation module includes: a magnetic induction coil disposed on the main current path, a signal processing circuit connected to the output terminal of the coil, and a pre-charging circuit, wherein the pre-charging circuit is connected between the input bus and the input terminal of the protected load. The energy distribution and recovery network includes: multiple parallel discharge channels that group the protection units within the three-dimensional core according to their breakdown voltages, each channel being connected in series with a resettable fuse and an inductor and then connected to a common discharge ground; and a bidirectional DC-DC converter connected to each inductor, the output of which is connected to a power bus or an energy storage capacitor. The controller receives the surge characteristic signal and voltage detection signal output by the signal processing circuit, and outputs control signals to the pre-charging circuit, the trigger voltage adjustment terminal of the three-dimensional core, and the enable terminal of the bidirectional DC-DC converter. The controller has a state machine inside.

7. The puncture-resistant, overvoltage surge protection circuit of claim 6, wherein, The vertically stacked spark gap array has 3 to 6 conductive layer pairs, with the vertical spacing of each layer increasing along the stacking direction and ranging from 200 nanometers to 2 micrometers; the thickness of the self-healing polymer medium is 10 micrometers to 50 micrometers; the forward breakdown voltage range of the asymmetric silicon carbide transient voltage suppressor is 30 volts to 100 volts, and the absolute value of the reverse breakdown voltage is 5 volts to 20 volts.

8. The puncture-resistant, overvoltage surge protection circuit of claim 6, wherein, The magnetic induction coil is a multi-turn spiral coil or solenoid with 2 to 20 turns; the signal processing circuit includes a differential amplifier and a comparator network, the bandwidth of the differential amplifier is 500 MHz to 10 GHz, and the response time of the comparator network is 1 nanosecond to 10 nanoseconds.

9. The puncture-resistant, overvoltage surge protection circuit of claim 6, wherein, The pre-charge circuit includes a charge pump, a current-limiting resistor, a switch, and a capacitor. The current-limiting resistor has a resistance of 0.01 ohms to 10 ohms. The switch is a silicon carbide metal-oxide-semiconductor field-effect transistor or a gallium nitride high electron mobility transistor. The capacitor has a capacitance of 10 picofarads to 100 nanofarads.

10. The puncture-resistant, overvoltage surge protection circuit of claim 6, wherein, The resettable fuse is a polymer positive temperature coefficient thermistor with a room temperature resistance of 1 milliohm to 100 milliohms; the inductance of the inductor is 100 nanohenries to 5 microhenries; the topology of the bidirectional DC-DC converter is flyback, buck, or buck-boost; the controller is a microcontroller, digital signal processor, or analog state machine, and the state machine includes at least three states.

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