DC power supply anti-surge circuit

Abstract

The utility model provides a DC power supply anti-surge circuit, comprising an overcurrent protection module, the input end of which is connected with the positive input end of input DC; the input end of the TVS tube is connected with the output end of the overcurrent protection module, and the output end of the TVS tube is connected with the negative input end of the input direct current; the input end of the diode is connected with the output end of the overcurrent protection module; the input end of the filtering module is connected with the output end of the diode and the output end of the TVS tube, and the output end of the filtering module outputs direct current voltage. The DC power supply anti-surge circuit can realize DC power supply surge protection based on the TVS tube, and is simple in circuit structure and easy to realize.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a direct current power supply surge protection circuit. Background Art

[0002] Surge is a transient disturbance that causes the instantaneous voltage on the power grid to exceed the rated normal voltage range under certain conditions. Usually this transient does not last too long, but the amplitude may be quite high, and it may be a sudden surge within just one millionth of a second. For example, thunder, disconnecting inductive loads, or connecting large loads will have a great impact on the power grid. In most cases, if the equipment or circuits connected to the power grid do not have surge protection measures, it is easy to damage the device, and the degree of damage is related to the voltage resistance level of the device.

[0003] Therefore, in order to improve the reliability of electronic products and the safety of human body, it is necessary to take protective measures against voltage transients and surges. Figure 1 As shown, it is mainly designed for AC power supply, such as using varistors, gas discharge tubes, common mode inductors, differential mode inductors and other devices, which results in the surge protection devices being too large in size and high in cost. Utility Model Content

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the utility model is to provide a DC power supply surge protection circuit, which can realize DC power supply surge protection based on TVS tube, has a simple circuit structure and is easy to implement.

[0005] To achieve the above-mentioned purpose and other related purposes, the utility model provides a DC power supply surge protection circuit, comprising: an overcurrent protection module, the input end of the overcurrent protection module is connected to the positive input end of the input DC power; a TVS tube, the input end of the TVS tube is connected to the output end of the overcurrent protection module, and the output end is connected to the negative input end of the input DC power; a diode, the input end of the diode is connected to the output end of the overcurrent protection module; a filter module, the input end of the filter module is connected to the output end of the diode and the output end of the TVS tube, and the output end outputs a DC voltage.

[0006] In an embodiment of the present invention, the overcurrent protection module adopts a resettable fuse.

[0007] In an embodiment of the present invention, the filter module adopts a π-type filter.

[0008] In one embodiment of the utility model, the π-type filter includes a first capacitor, a common-mode inductor and an inductor; the input end of the first capacitor is connected to the output end of the diode, and the output end is connected to the output end of the TVS tube; the two input ends of the common-mode inductor are connected to the input end and the output end of the first capacitor, one output end is grounded, and the other output end is connected to the input end of the inductor; the output end of the inductor outputs the DC voltage.

[0009] In one embodiment of the present invention, a second capacitor is further included, wherein an input end of the second capacitor is connected to the output end of the diode, and an output end of the second capacitor is connected to the output end of the TVS tube.

[0010] In an embodiment of the present invention, a third capacitor, a fourth capacitor and a fifth capacitor are further included, and the input ends of the third capacitor, the fourth capacitor and the fifth capacitor are connected to the output end of the filter module, and the output end is grounded.

[0011] In an embodiment of the present invention, the leakage current of the TVS tube is not less than 500A.

[0012] As described above, the DC power supply surge protection circuit described in the utility model has the following beneficial effects:

[0013] (1) Able to realize DC power supply surge protection based on TVS tube;

[0014] (2) The circuit structure is simple, the cost is low, and it is easy to implement;

[0015] (3) It can be applied to different DC power supply application scenarios and is extremely practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Shown is a schematic structural diagram of a DC power supply surge protection circuit in an embodiment of the prior art;

[0017] Figure 2 Shown is a schematic structural diagram of a DC power supply surge protection circuit in one embodiment of the utility model;

[0018] Figure 3 FIG. 1 is a circuit diagram of a DC power supply surge protection circuit in one embodiment of the present utility model. DETAILED DESCRIPTION

[0019] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0020] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0021] The DC power supply surge protection circuit of the utility model realizes surge protection of the DC power supply based on the TVS tube, ensures the stability and reliability of the circuit structure, and has a simple structure, low cost, and is easy to implement, thus being extremely practical.

[0022] like Figure 2 As shown, in one embodiment, the DC power supply surge protection circuit of the utility model includes an overcurrent protection module 1, a TVS tube 2, a diode 3 and a filter module 4. The overcurrent protection module 1, the TVS tube 2, the diode 3 and the filter module 4 are connected in sequence.

[0023] like Figure 3 As shown, the input end of the overcurrent protection module 1 is connected to the positive input end of the input DC power J20. In this embodiment, the input DC power is 24 V. The overcurrent protection module 1 uses a self-recovery fuse to prevent circuit damage caused by excessive load current.

[0024] The input end of the TVS tube 2 is connected to the output end of the overcurrent protection module 1, and the output end is connected to the negative input end of the input DC power J20. The TVS tube 2 has surge protection capability, thereby realizing surge protection function.

[0025] The input end of the diode 3 is connected to the output end of the overcurrent protection module 1 to realize the reverse plug-in protection function. When the positive and negative input ends of the input DC power are reversely connected, the DC power supply surge protection circuit will not work.

[0026] The input end of the filter module 4 is connected to the output end of the diode 3 and the output end of the TVS tube 2, and the output end outputs a DC voltage. In one embodiment, the filter module 4 adopts a π-type filter, which is conducive to overconduction experiments and transient pulse group experiments. Among them, the π-type filter includes a first capacitor 41, a common mode inductor 42 and an inductor 43. The input end of the first capacitor 41 is connected to the output end of the diode 3, and the output end is connected to the output end of the TVS tube 2. The two input ends of the common mode inductor 42 are connected to the input end and output end of the first capacitor 41, one output end is grounded, and the other output end is connected to the input end of the inductor 43. The output end of the inductor 43 outputs the DC voltage.

[0027] In addition, in order to prevent the system from restarting due to voltage drop and current shock at the moment of the surge test, in one embodiment, the DC power supply surge protection circuit of the utility model also includes multiple capacitors, such as a second capacitor 5, a third capacitor 6, a fourth capacitor 7 and a fifth capacitor 8. The input end of the second capacitor 5 is connected to the output end of the diode 3, and the output end is connected to the output end of the TVS tube 2. The input ends of the third capacitor 6, the fourth capacitor 7 and the fifth capacitor 8 are connected to the output end of the filter module 4, and the output end is grounded.

[0028] The DC power supply surge protection circuit of the utility model can pass the surge level 3 test based on a single TVS tube. The surge level 3 parameters are: waveform is 8 / 20uS, differential mode is +-1000V, and internal resistance is 2 ohms. Therefore, the leakage current of the TVS tube is not less than 500A.

[0029] When the TVS tube uses 5.0SMDJ26CA, VC=42.1V, IPP=119A, P=5000W. According to the TVS tube manual, 5000W power is measured according to 10 / 1000us surge waveform. It can be seen that at 20us, power=25KW, that is, leakage current=25KW / 42.1V=593A, thus meeting the surge level 3 test.

[0030] In summary, the DC power supply surge protection circuit of the utility model can realize DC power supply surge protection based on TVS tube; the circuit structure is simple, the cost is low, and it is easy to implement; it can be applied to different DC power supply application scenarios and is very practical. Therefore, the utility model effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

[0031] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. A DC power supply surge protection circuit, characterized in that: include: An overcurrent protection module, wherein an input terminal of the overcurrent protection module is connected to a positive input terminal of an input direct current; A TVS tube, wherein the input end of the TVS tube is connected to the output end of the overcurrent protection module, and the output end of the TVS tube is connected to the negative input end of the input direct current; A diode, the input end of the diode is connected to the output end of the overcurrent protection module; A filter module, wherein the input end of the filter module is connected to the output end of the diode and the output end of the TVS tube, and the output end outputs a DC voltage.

2. The DC power supply surge protection circuit according to claim 1, characterized in that: The overcurrent protection module adopts a self-recovering fuse.

3. The DC power supply surge protection circuit according to claim 1, characterized in that: The filtering module adopts a π-type filter.

4. The DC power supply surge protection circuit according to claim 3, characterized in that: The π-type filter includes a first capacitor, a common-mode inductor and an inductor; the input end of the first capacitor is connected to the output end of the diode, and the output end is connected to the output end of the TVS tube; the two input ends of the common-mode inductor are connected to the input end and the output end of the first capacitor, one output end is grounded, and the other output end is connected to the input end of the inductor; the output end of the inductor outputs the DC voltage.

5. The DC power supply surge protection circuit according to claim 1, characterized in that: It also includes a second capacitor, wherein the input end of the second capacitor is connected to the output end of the diode, and the output end of the second capacitor is connected to the output end of the TVS tube.

6. The DC power supply surge protection circuit according to claim 1, characterized in that: It also includes a third capacitor, a fourth capacitor and a fifth capacitor, the input ends of the third capacitor, the fourth capacitor and the fifth capacitor are connected to the output end of the filter module, and the output end is grounded.

7. The DC power supply surge protection circuit according to claim 1, characterized in that: The leakage current of the TVS tube is not less than 500A.

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