Lightning stroke protection circuit

Abstract

The invention discloses a lightning stroke protection circuit, and relates to the technical field of electronics. The circuit comprises a semiconductor switching device, a first resistor, a first voltage stabilizing diode, a second voltage stabilizing diode and a second resistor, the first end of the semiconductor switching device is connected with the negative electrode of the first voltage stabilizing diode, the connection point between the first end of the semiconductor switching device and the negative electrode of the first voltage stabilizing diode is connected with the positive electrode of a bus, and the positive electrode of the first voltage stabilizing diode is connected with the first end of the first resistor and the first end of the second resistor. The second end of the first resistor is connected with the second end of the semiconductor switching device, the third end of the semiconductor switching device is connected with the negative electrode of the bus, and the second end and the third end of the semiconductor switching device are reversely connected in parallel with a second voltage stabilizing diode; the second end of the second resistor is connected with the cathode of the bus. The circuit is small in size.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and particularly to a lightning protection circuit. Background Art

[0002] Currently, lightning strikes are a major threat to electronic products. In certain specific scenarios (such as airplanes, iron towers, etc.), lightning protection becomes of utmost importance. With the development of electronic technology, more and more products will face the test of lightning strikes. Some products that originally had no lightning protection requirements will also be used in environments with lightning strike risks due to technological iterations and changing needs, which also poses new requirements for these products.

[0003] Conventional lightning protection circuits often have a relatively large volume. The fundamental reason is that lightning surges often have a long duration and a large current (and thus the energy they carry is relatively large). For general electronic devices, the volume is positively correlated with the power they can withstand. Due to changing needs and technological iterations, miniaturization, high density, and high integration will be the development path of future products.

[0004] Therefore, there is an urgent need in the prior art for a lightning protection circuit with a relatively small volume. Summary of the Invention

[0005] Based on this, in order to address the above technical problems, it is necessary to provide a lightning protection circuit with a relatively small volume.

[0006] The present invention adopts the following technical solutions:

[0007] The present invention provides a lightning protection circuit, including: a semiconductor switching device, a first resistor, a first zener diode, a second zener diode, and a second resistor; the first end of the semiconductor switching device is connected to the negative electrode of the first zener diode, and the connection point between the first end of the semiconductor switching device and the negative electrode of the first zener diode is connected to the positive pole of the busbar. The positive electrode of the first zener diode is respectively connected to the first end of the first resistor and the first end of the second resistor. The second end of the first resistor is connected to the second end of the semiconductor switching device. The third end of the semiconductor switching device is connected to the negative pole of the busbar. The second zener diode is reversely connected in parallel between the second end and the third end of the semiconductor switching device; the second end of the second resistor is connected to the negative pole of the busbar;

[0008] The second resistor is used to limit the current flowing through the first zener diode.

[0009] When a high-voltage surge signal generated by lightning strikes is introduced into the bus, the voltage on the bus exceeds the clamping voltage of the first zener diode, and the first zener diode conducts. The high-voltage surge signal is transmitted to the first resistor. After passing through the first resistor, the high-voltage surge signal is clamped by the second zener diode within the safe voltage range for the semiconductor switching device to turn on.

[0010] Optionally, the semiconductor switching device is an NMOS transistor. The first end of the semiconductor switching device is the drain of the NMOS transistor, the second end of the semiconductor switching device is the gate of the NMOS transistor, and the third end of the semiconductor switching device is the source of the NMOS transistor.

[0011] Optionally, the semiconductor switching device is a triac. The first end of the semiconductor switching device is the first anode of the triac, the second end of the semiconductor switching device is the G pole of the triac, and the third end of the semiconductor switching device is the second anode of the triac.

[0012] Optionally, the lightning protection circuit further includes: an energy-consuming direct-through device. The first end of the semiconductor switching device is connected to the negative electrode of the first zener diode through the energy-consuming direct-through device; the connection point between the energy-consuming direct-through device and the first end of the semiconductor switching device is connected to the positive electrode of the bus.

[0013] The energy-consuming direct-through device is used to consume the energy of the high-voltage surge signal after the semiconductor switching device conducts.

[0014] Optionally, the first resistor and the second resistor are resistors in the hundreds of kiloohm range.

[0015] Optionally, the clamping voltage level of the lightning protection circuit is determined according to the clamping voltage of the first zener diode.

[0016] Optionally, the lightning protection circuit further includes a transient voltage suppressor diode TVS, which is connected in parallel between the first end and the third end of the semiconductor switching device.

[0017] The above at least one technical solution adopted by the present invention can achieve the following beneficial effects:

[0018] When a high-voltage surge signal generated by lightning strikes is introduced into the bus, the voltage on the bus exceeds the clamping voltage of the first zener diode, and the first zener diode conducts. The high-voltage surge signal is transmitted to the first resistor. After passing through the first resistor, the high-voltage surge signal is clamped by the second zener diode within the safe voltage range for the semiconductor switching device to turn on. In this way, the subsequent circuit is protected from being damaged by lightning surges. The circuit includes a semiconductor switching device, a first resistor, a second resistor, and two zener diodes, which can greatly reduce the volume of the lightning protection circuit. Description of the Drawings

[0019] The accompanying drawings described herein are used to provide a further understanding of the present invention and form a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0020] Figure 1 is a schematic structural diagram of a lightning protection circuit provided by the present invention;

[0021] Figure 2 is a schematic structural diagram of another lightning protection circuit provided by the present invention;

[0022] Figure 3 is a structural diagram of a lightning protection circuit when the semiconductor switching device is an NMOS transistor;

[0023] Figure 4 is a structural diagram of a lightning protection circuit when the semiconductor switching device is a triac;

[0024] Figure 5 is a simulation waveform diagram of the protection effect of a lightning protection circuit provided by the present invention.

[0025] Description of reference numerals:

[0026] 100, lightning protection circuit; 101, semiconductor switching device; 102, first resistor; 103, first zener diode; 104, second zener diode; 105, second resistor; 106, positive pole of the bus; 107, negative pole of the bus;

[0027] 201, current limiting resistor. Detailed embodiments

[0028] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0029] It is understandable that the serial numbers assigned to components in this application, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. The terms "connection" and "coupling" as used in this application, unless otherwise specified, both include direct and indirect connection (coupling). In the description of this application, it should be understood that the orientation or positional relationship indicated by orientation terms such as "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to this application. In this application, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In this application, the way to distinguish elements is not based on the difference in names, but on the difference in functions of the elements.

[0030] In the prior art, the following three methods are usually used for lightning protection:

[0031] (1) The lightning protection circuit based on a gas discharge tube is relatively common in conventional lightning protection. Its main device is a gas discharge tube (Gas Discharge Tube, GDT). The biggest advantage of this device is that it basically has specifications with discharge power ranging from small to large. When it is conventionally used as a protection circuit, it is usually connected in parallel between the " + " and " - " of the busbar, or between " + " and the ground and between " - " and the ground.

[0032] (2) A transient voltage suppressor (TVS) is a semiconductor type of protection device. The protection circuit using a TVS often connects the TVS in parallel between the protected interface and the ground plane. When a surge comes, the TVS turns on and clamps the lightning surge within its protection threshold.

[0033] (3) A semiconductor discharge tube (Transient Solid State Switch, TSS) device, that is, a semiconductor solid - state discharge tube, is designed in a PNPN structure. When in use, it is generally directly connected in parallel between the protected interface and the ground, or between the two protected busbars. When a lightning surge comes, the TSS device turns on to achieve the function of clamping the surge voltage.

[0034] However, the above - mentioned methods have the following disadvantages:

[0035] (1) The characteristics of a gas discharge tube are high insulation resistance, very small parasitic capacitance, and strong surge protection ability. However, this type of device often has a large volume, and the gas discharge tube has a large discharge delay and a high operating voltage threshold, so its protection ability for surges with a relatively fast rising edge is not so strong. Therefore, in a lightning surge protection circuit designed with a gas discharge tube, other protection devices with smaller discharge delays need to be added to achieve effective protection, further increasing the area of the protection circuit. At the same time, the device height of the gas discharge tube itself is relatively high, and it cannot be used in some products with height limitations.

[0036] (2) The protection power of conventional TVS devices is not very large. When facing strong and long-lasting lightning surges, the devices may be damaged, thus losing their protection function. Moreover, the protection power of TVS devices is strongly related to their volume. Larger surges require a larger volume to be protected, and the device height is also relatively high. The junction capacitance of TVS devices also increases with the increase of their protection power, and it has a relatively large impact on signals during normal operation.

[0037] (3) Although TSS devices have good switching characteristics, small junction capacitance, and large absorption power, they have a fatal defect, that is, there will still be a residual voltage spike after absorbing the surge. If you want to remove this spike, you must add a protection device with a faster response speed behind it. If this spike is not removed, it will damage the protected device at the subsequent stage.

[0038] Based on this, the present invention provides a lightning protection circuit, which solves the problems of large volume and high device height of the conventional lightning surge protection circuit, so that lightning surge protection can be applied to smaller and thinner products. At the same time, conventional devices can also be used for lightning surge protection design, expanding the range of device usage for this type of application and achieving a more flexible design. It can also achieve a higher level of lightning surge protection without increasing the volume through the selection of device parameters.

[0039] The following will describe in detail the technical solutions provided by each embodiment of the present invention with reference to the accompanying drawings.

[0040] Figure 1Schematic diagram of the structure of a lightning protection circuit in the present invention. The circuit 100 includes: a semiconductor switching device 101, a first resistor 102, a first zener diode 103, a second zener diode 104, and a second resistor 105; a first end of the semiconductor switching device 101 is connected to the negative electrode of the first zener diode 103, and a connection point between the first end of the semiconductor switching device 101 and the negative electrode of the first zener diode 103 is connected to the positive electrode 106 of the bus. The positive electrode of the first zener diode 103 is respectively connected to the first end of the first resistor 102 and the first end of the second resistor 105. The second end of the first resistor 102 is connected to the second end of the semiconductor switching device 101. The third end of the semiconductor switching device 101 is connected to the negative electrode 107 of the bus. The second zener diode 104 is reversely connected in parallel between the second end and the third end of the semiconductor switching device 101; the second end of the second resistor 105 is connected to the negative electrode 107 of the bus.

[0041] The second resistor 105 is used to limit the current flowing through the first zener diode 103.

[0042] When a high-voltage surge signal generated by lightning strikes is introduced into the bus, the voltage on the bus exceeds the clamping voltage of the first zener diode 103, and the first zener diode 103 conducts. The high-voltage surge signal is transmitted to the first resistor 102. After passing through the first resistor 102, the high-voltage surge signal is clamped by the second zener diode 104 within the safe voltage range for the semiconductor switching device 101 to turn on.

[0043] In one embodiment, the lightning protection circuit further includes: an energy-consuming direct-through device. The first end of the semiconductor switching device 101 is connected to the negative electrode of the first zener diode 103 through the energy-consuming direct-through device; the connection point between the energy-consuming direct-through device and the first end of the semiconductor switching device 101 is connected to the positive electrode 106 of the bus; the energy-consuming direct-through device is used to consume the energy of the high-voltage surge signal after the semiconductor switching device 101 conducts.

[0044] The energy-consuming direct-through device can be a resistor, an inductor, a magnetic bead, or a self-recovery fuse. Taking the energy-consuming direct-through device as a current-limiting resistor as an example for illustration, as Figure 2 shown, the first end of the semiconductor switching device 101 is connected to the negative electrode of the first zener diode 103 through a current-limiting resistor 201; the connection point between the current-limiting resistor 201 and the first end of the semiconductor switching device 101 is connected to the positive electrode 106 of the bus.

[0045] The current-limiting resistor 201 is used to consume the energy of the high-voltage surge signal after the semiconductor switching device 101 conducts.

[0046] Among them, the first resistor 102 and the second resistor 105 are resistors in the order of hundreds of kiloohms. The current-limiting resistor 201 is less than a preset resistor threshold, and the resistance value of the current-limiting resistor 201 should not be too large. The instantaneous power is selected according to the tolerance level. The clamping voltage level of the lightning protection circuit is determined according to the clamping voltage of the first zener diode 103.

[0047] Among them, the semiconductor switching device 101 can be an N-channel Metal-Oxide-Semiconductor Field-Effect Transistor (NMOS). The first end of the semiconductor switching device 101 is the drain of the NMOS transistor, the second end of the semiconductor switching device 101 is the gate of the NMOS transistor, and the third end of the semiconductor switching device 101 is the source of the NMOS transistor; as Figure 3 shown, Figure 3 is the structural diagram of the lightning protection circuit when the semiconductor switching device is an NMOS transistor.

[0048] Specifically, taking the semiconductor switching device 101 as an NMOS transistor as an example, the working principle of the lightning protection circuit is described. When a lightning surge signal comes, the voltage on the bus exceeds the clamping voltage V1 of the first zener diode 103. At this time, the first zener diode conducts, and then the lightning surge signal is transmitted to the first resistor 102 in front of the gate of the NMOS transistor. After passing through the first resistor 102, the lightning surge signal is clamped within the safe voltage V2 range for the NMOS transistor to turn on by the zener diode D2. The function of the first resistor 102 is to limit the current flowing through the second zener diode 104 so that the second zener diode 104 is not damaged. The function of the second resistor 105 is to limit the current flowing through the first zener diode 103 so that the first zener diode 103 is not damaged. The current-limiting resistor 201 is an absorption resistor in the circuit. After the NMOS conducts, the current on the NMOS transistor and the current-limiting resistor 201 will increase instantaneously. At this time, the energy of the surge will be consumed on the current-limiting resistor 201 and the NMOS transistor, thereby protecting the subsequent stage of the circuit from being damaged by the lightning surge. The clamping voltage level of this lightning protection circuit is determined by the clamping voltage of the zener diode D1.

[0049] Among them, the subsequent stage of the circuit is connected in parallel between the first end and the third end of the semiconductor switching device 101.

[0050] The lightning protection circuit also includes a transient voltage suppression diode TVS, which is connected in parallel between the first end and the third end of the semiconductor switching device 101. The transient voltage suppression diode TVS is located between the semiconductor switching device 101 and the subsequent stage of the circuit.

[0051] When the semiconductor switch device 101 in the circuit is a triac, the same function can also be achieved, and the protection level of the circuit can be improved. The connection method of the triac in the lightning protection circuit is as follows: the first end of the semiconductor switch device 101 is the first anode of the triac, the second end of the semiconductor switch device 101 is the G pole of the triac, and the third end of the semiconductor switch device 101 is the second anode of the triac; as Figure 4 shown, Figure 4 Figure Figure 4 is the structural diagram of the lightning protection circuit when the semiconductor switch device is a triac.

[0052] It should be noted that when using a triac to implement this lightning protection circuit, it is necessary to pay attention to stress elimination of the voltage on the protected bus after completing the lightning surge protection, that is, reducing the bus voltage level to 0 level for a certain time (in milliseconds) before the clamping state can be released.

[0053] As Figure 5 shown, Figure 5 Figure Figure 5 is the simulation waveform diagram of the protection effect of the lightning protection circuit. The solid line waveform in the figure is the input surge waveform, the signal internal resistance is 1 ohm, and the dotted line waveform is the waveform of the subsequent stage of the circuit. When the simulation result is formed, a 28V DC voltage is continuously applied to the signal bus, and the designed surge clamping voltage of the circuit is 28V. It can be seen from the simulation result that the circuit can effectively clamp the lightning surge within the specified range.

[0054] The beneficial effects of the lightning protection circuit of the present invention include: (1) greatly reducing the design volume of the lightning protection circuit, especially in the protection requirements of low power, the volume is very small, and it can be widely promoted in miniaturized applications. (2) At the same time, the height of the lightning protection circuit is also reduced, which is very friendly to some products with height restrictions. Thus, the application product range of the lightning surge protection circuit is expanded. (3) At the same time, it provides a new idea for lightning surge protection, enabling the device selection range in the design of this type of circuit to be extended to the range of conventional devices, reducing the selection difficulty and design difficulty. (4) At the same time, the present invention can also arbitrarily change the form and device parameters according to the design requirements to achieve complete matching with the requirements.

[0055] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded by the present invention.

Claims

1. A lightning protection circuit, characterized in that: The lightning protection circuit comprises: a semiconductor switch device, a first resistor, a first voltage stabilizing diode, a second voltage stabilizing diode and a second resistor; The first end of the semiconductor switch device is connected to the cathode of the first voltage-stabilizing diode, and the connection point between the first end of the semiconductor switch device and the cathode of the first voltage-stabilizing diode is connected to the anode of the busbar, the anode of the first voltage-stabilizing diode is connected to the first end of the first resistor and the first end of the second resistor respectively, the second end of the first resistor is connected to the second end of the semiconductor switch device, the third end of the semiconductor switch device is connected to the cathode of the busbar, the second voltage-stabilizing diode is connected in reverse parallel to the second end and the third end of the semiconductor switch device; the second end of the second resistor is connected to the cathode of the busbar; The second resistor is used to limit the current flowing through the first voltage stabilizing diode; When a high-voltage surge signal generated by a lightning strike is introduced into the bus, the voltage on the bus exceeds the clamping voltage of the first Zener diode, the first Zener diode is turned on, and the high-voltage surge signal is transmitted to the first resistor. After passing through the first resistor, the high-voltage surge signal is clamped by the second Zener diode to within the safe voltage range for turning on the semiconductor switching device.

2. The lightning protection circuit according to claim 1, characterized in that: The semiconductor switch device is an NMOS tube, the first end of the semiconductor switch device is the drain of the NMOS tube, the second end of the semiconductor switch device is the gate of the NMOS tube, and the third end of the semiconductor switch device is the source of the NMOS tube.

3. The lightning protection circuit according to claim 1, characterized in that: The semiconductor switch device is a bidirectional thyristor, the first end of the semiconductor switch device is the first anode of the bidirectional thyristor, the second end of the semiconductor switch device is the G pole of the bidirectional thyristor, and the third end of the semiconductor switch device is the second anode of the bidirectional thyristor.

4. The lightning protection circuit according to claim 1, characterized in that: The lightning protection circuit further includes an energy-consuming direct-pass device, through which the first end of the semiconductor switch device is connected to the cathode of the first voltage-stabilizing diode; and a connection point between the energy-consuming direct-pass device and the first end of the semiconductor switch device is connected to the anode of the busbar; The energy-consuming direct-through device is used to consume the energy of the high-voltage surge signal after the semiconductor switch device is turned on.

5. The lightning protection circuit according to claim 1, characterized in that: The first resistor and the second resistor are resistors in the order of hundreds of kilo-ohms.

6. The lightning protection circuit according to claim 1, characterized in that: The clamping voltage level of the lightning protection circuit is determined according to the clamping voltage of the first voltage stabilizing diode.

7. The lightning protection circuit according to claim 1, characterized in that: The lightning protection circuit further includes a transient suppression diode TVS, which is connected in parallel between the first end of the semiconductor switch device and the third end of the semiconductor switch device.

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