Lightning protection and insulation voltage-withstanding protection circuit

Abstract

The utility model relates to a lightning protection and insulation withstand voltage protection circuit, which is characterized in that a circuit is formed by piezoresistors MOV1, MOV2, MOV3 and MOV4, when surge voltage such as lightning stroke and the like exceeds rated voltage, the values of the piezoresistors in a parallel circuit are suddenly reduced to be conducted, high voltage passes through gas discharge tubes G1 and G2, and after lightning transient overvoltage is discharged, the circuit is discharged by a grounding wire. Meanwhile, the resistance value of a piezoresistor MOV5 connected in the LN circuit in parallel is sharply reduced to be switched on, and a fuse Ft is burnt out by instantaneous strong current, so that electric equipment such as an LED power supply and the like is prevented from being damaged. In addition, the technical scheme has a protection mode of lightning protection and discharge resistor combination of resistors R1, R2 and R3, can meet the requirements of lightning protection and high voltage, has the characteristics of no leakage current, no follow current and the like, and effectively prolongs the service life of an LED system.

Description

Technical Field

[0001] The utility model relates to the field of LED lighting equipment, in particular to a lightning protection and insulation withstand voltage protection circuit. Background Art

[0002] Surge, also called surge, is an instantaneous overvoltage that exceeds the normal voltage. It generally refers to a high current caused by a short-term high voltage like a "wave" in the power grid. There are two reasons for the generation of surge voltage, one is lightning, and the other is when the load on the circuit is connected or disconnected. The AC-DC switching power supply connected to the mains is often used as a primary power supply to provide a stable bus voltage for the subsequent system. Since the AC-DC switching power supply is connected to the mains, and the mains is often affected by some natural factors (such as lightning and lightning) and application environment (such as the opening or closing of a large inductive or capacitive load on the mains), a transient voltage or current spike is generated. This surge voltage will damage the LED and affect its life and performance. Especially in LED lamps, due to the large number of LEDs, the impact of surge voltage is more obvious. Therefore, measures need to be taken to prevent surge voltage from damaging the LED.

[0003] China Patent Publication (Announcement) No.: CN205753380U, Patent Title: Lightning Surge Protection Circuit, which discloses "A lightning surge protection circuit, which is formed by connecting a first discharge circuit and a noise filtering circuit, wherein the first discharge circuit is formed by connecting a varistor MOV1 and a resistor R1, wherein the resistor R1 is connected in series after the varistor MOV1; the varistor MOV1 is used to provide a low-resistance discharge path for the impact current generated by the lightning surge; the resistor R1 is used to increase the input impedance so that more impact current passes through the varistor MOV1. OV1 discharge; the noise filtering circuit is composed of a differential mode inductor L1 and a safety X capacitor CX, and the differential mode inductor L1 is connected in series before the safety X capacitor; when a lightning surge generates an impact current, the noise filtering circuit is used to further filter out the residual voltage spike of the first discharge circuit; and when the noise of the subsequent circuit is transmitted forward, the noise filtering circuit is used to filter out the noise from the subsequent circuit. The technical solution has achieved the beneficial effect of "greatly reducing the damage of the switching power supply suffered by lightning surge in actual use; and improving the electromagnetic compatibility (EMI) performance of the switching power supply".

[0004] However, the circuit uses large electronic components such as differential mode inductor L1 and capacitor CX, which increases the size of the entire switching power supply, which is not conducive to the development trend of lightweight design. Summary of the invention

[0005] The utility model aims to provide a lightning protection and insulation withstand voltage protection circuit to solve the problems raised in the above background technology.

[0006] In order to solve the above technical problems, the utility model is achieved through the following technical measures: a lightning protection and insulation withstand voltage protection circuit, including a live wire input Lin terminal, a neutral wire input Nin terminal, a live wire output Lout terminal, a neutral wire output Nout terminal, and a ground FG terminal, wherein there are three parallel branches between the live wire and the neutral wire, the first parallel branch is formed by a varistor MOV1 and a varistor MOV3 connected in series, the second parallel branch is formed by a varistor MOV2 and a varistor MOV4 connected in series, and the third parallel branch is formed by a varistor MOV5 and a fuse Ft connected in series; after the gas discharge tube G1 and the gas discharge tube G2 are connected in series, one end is connected to the middle part of the varistor MOV1 and the varistor MOV3, and then connected to the middle part of the varistor MOV2 and the varistor MOV4, and the other end is connected to the ground FG terminal; after the resistors R1, R2, and R3 are connected in series, they are connected in parallel with the gas discharge tube G1 and the gas discharge tube G2.

[0007] Compared with the prior art, the utility model has the advantages that: by forming a circuit with varistors MOV1, MOV2, MOV3, and MOV4, when the voltage exceeds the rated voltage due to surge voltage such as lightning, the varistor value in the parallel circuit drops sharply and conducts, allowing the high voltage to pass through the gas discharge tubes G1 and G2, and discharge the transient overvoltage of lightning, and then discharge it from the grounding wire. At the same time, the resistance value of the varistor MOV5 connected in parallel in the LN circuit drops sharply and conducts, and the instantaneous strong current burns the fuse Ft, so that the LED power supply and other electrical equipment are protected from damage. In addition, the technical solution has a protection mode of lightning protection and a combination of resistors R1, R2, and R3 discharge resistors, which can meet the requirements of lightning protection high voltage, and has the characteristics of no leakage current, no continuous current, etc., and effectively prolongs the life of the LED system. This new circuit greatly reduces the damage of the switching power supply to lightning surges in actual use, and because there are no large-volume components such as inductors and capacitors, the entire switching power supply is lightweight and compact. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0009] In the attached picture:

[0010] Figure 1 This is the lightning protection and insulation withstand voltage protection circuit diagram described in the utility model. DETAILED DESCRIPTION

[0011] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0012] Example 1

[0013] Please refer to Figure 1 The present embodiment provides a lightning protection and insulation withstand voltage protection circuit, including a live wire input Lin terminal, a neutral wire input Nin terminal, a live wire output Lout terminal, a neutral wire output Nout terminal, and a ground FG terminal, wherein there are three parallel branches between the live wire and the neutral wire, the first parallel branch is formed by a varistor MOV1 and a varistor MOV3 connected in series, the second parallel branch is formed by a varistor MOV2 and a varistor MOV4 connected in series, and the third parallel branch is formed by a varistor MOV5 and a fuse Ft connected in series; after the gas discharge tube G1 and the gas discharge tube G2 are connected in series, one end is connected to the middle part of the varistor MOV1 and the varistor MOV3, and then connected to the middle part of the varistor MOV2 and the varistor MOV4, and the other end is connected to the ground FG terminal; after the resistor R1, the resistor R2, and the resistor R3 are connected in series, they are connected in parallel with the gas discharge tube G1 and the gas discharge tube G2.

[0014] The present embodiment provides a lightning protection and insulation withstand voltage protection circuit, the working principle of which is: by forming a circuit with varistors MOV1, MOV2, MOV3, and MOV4, when the voltage exceeds the rated voltage due to surge voltage such as lightning, the varistor value in the parallel circuit drops sharply and conducts, allowing the high voltage to pass through the gas discharge tubes G1 and G2, and discharge the lightning transient overvoltage, and then discharge it from the grounding wire. At the same time, the resistance value of the varistor MOV5 connected in parallel in the LN circuit drops sharply and conducts, and the instantaneous strong current causes the fuse Ft to burn out, so that the electrical equipment such as the LED power supply is protected from damage. In addition, the technical solution has a protection mode of lightning protection and a combination of resistors R1, R2, and R3 discharge resistors, which can meet the requirements of lightning protection high voltage, and has the characteristics of no leakage current, no continuous current, etc., effectively extending the life of the LED system.

[0015] The beneficial effects of the utility model are as follows: the novel circuit greatly reduces the damage of the switching power supply caused by lightning surge in actual use, and since there are no large-volume components such as inductors and capacitors, the entire switching power supply is lightweight and compact.

[0016] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "horizontal", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0017] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0018] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. Although the utility model is described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions recorded in the above embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A lightning protection and insulation withstand voltage protection circuit, comprising a live wire input Lin terminal, a neutral wire input Nin terminal, a live wire output Lout terminal, a neutral wire output Nout terminal, and a ground FG terminal, characterized in that: There are three parallel branches between the live wire and the neutral wire, the first parallel branch is formed by the varistor MOV1 and the varistor MOV3 connected in series, the second parallel branch is formed by the varistor MOV2 and the varistor MOV4 connected in series, and the third parallel branch is formed by the varistor MOV5 and the fuse Ft connected in series; after the gas discharge tube G1 and the gas discharge tube G2 are connected in series, one end is connected to the middle part of the varistor MOV1 and the varistor MOV3, and then connected to the middle part of the varistor MOV2 and the varistor MOV4, and the other end is connected to the ground FG end; after the resistor R1, the resistor R2, and the resistor R3 are connected in series, they are connected in parallel with the gas discharge tube G1 and the gas discharge tube G2.

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