Power supply lightning protection device

Abstract

The utility model discloses a power supply lightning protection device comprising a housing and a circuit board in the housing, and the circuit board is provided with a lightning protection circuit, a rectifier bridge and a switching power supply chip. The lightning protection circuit comprises a power input end, an isolation transformer, a power output end, a first discharge tube, a second discharge tube, a first varistor, a second varistor, a third varistor, a fourth varistor and a first capacitor. The first piezoresistor is connected between the L end and the N end of the power input end, the L end of the power input end is further connected with one end of the first discharge tube through the second piezoresistor, and the N end of the power input end is further connected with one end of the first discharge tube through the third piezoresistor. The secondary side of the isolation transformer is respectively connected with a first capacitor and a fourth piezoresistor in parallel, the fourth piezoresistor is also grounded through the second discharge tube, and the secondary side of the isolation transformer is connected with the power supply output end; the beneficial effects are that the lightning protection performance is improved through multi-device and multi-stage lightning protection processing.

Description

Technical Field

[0001] The utility model relates to the technical field of lightning protection, in particular to a power supply lightning protection device. Background Art

[0002] At present, efficient and comprehensive monitoring systems are widely used in all walks of life. Due to the characteristics of low voltage and micro current, the monitoring system has weak anti-interference ability, which greatly increases the possibility of monitoring system equipment being struck by lightning.

[0003] Especially in mountainous areas, the terrain is complex, especially in areas with an average altitude of 4,000 meters, where cold and warm air currents meet, rainfall is frequent, and in some areas with high lightning incidence, the annual lightning period is as long as 4-5 months; continuous strong lightning strikes have caused great damage to various ground communication equipment (mostly monitoring equipment) deployed in the field, especially the power module of the communication equipment is severely damaged.

[0004] In thunderstorm weather, lightning current and strong electromagnetic pulses often couple into the equipment through the power line, making the power supply system vulnerable to lightning strikes, which in turn causes damage to the equipment. Most common power supply lightning protection products only use lightning arresters. Although they can discharge most of the lightning current, there is still residual pressure, which causes damage to subsequent equipment. Therefore, it is necessary to improve the lightning protection circuit of the power supply to improve the lightning protection performance. Utility Model Content

[0005] In view of the defects in the prior art, the utility model provides a power supply lightning protection device to improve the lightning protection performance.

[0006] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0007] A power supply lightning protection device comprises a housing and a circuit board arranged in the housing, wherein the circuit board is provided with a lightning protection circuit, a rectifier bridge and a switching power supply chip, wherein the lightning protection circuit comprises a power supply input terminal, an isolation transformer, a power supply output terminal, a first discharge tube, a second discharge tube, a first varistor, a second varistor, a third varistor, a fourth varistor and a first capacitor;

[0008] The power input terminal is respectively connected to the primary side of the isolation transformer, the first varistor is connected between the L and N terminals of the power input terminal, the L terminal of the power input terminal is also connected to one end of the first discharge tube through the second varistor, the N terminal of the power input terminal is also connected to one end of the first discharge tube through the third varistor, and the other end of the first discharge tube is grounded;

[0009] The secondary side of the isolation transformer is respectively connected in parallel with the first capacitor and the fourth varistor, and the fourth varistor is also grounded through the second discharge tube. The secondary side of the isolation transformer is connected to the power output end, and the power output end is connected to the input end of the rectifier bridge. The output end of the rectifier bridge is connected to the switching power chip, and the switching power chip is further connected to an external monitoring device.

[0010] Preferably, the L end of the power input end is also connected to a wire-wound resistor R1 for protection.

[0011] Preferably, a high-voltage filter capacitor is also connected in parallel to the output end of the rectifier bridge.

[0012] Preferably, a clamping circuit is also connected between the rectifier bridge and the switching power supply chip.

[0013] Preferably, the clamping circuit includes a decoupling capacitor, a resistor R2, a capacitor C2 and a diode; the resistor R2 and the capacitor C2 are connected in parallel, and one of the common ends is grounded through the decoupling capacitor, the other common end is connected to the cathode of the diode, and the anode of the diode is connected to the switching power supply chip.

[0014] Preferably, the rectifier bridge adopts a surface-mount rectifier module.

[0015] Preferably, a signal surge protector is installed at the serial port of the monitoring device.

[0016] Preferably, the first varistor, the second varistor, the third varistor and the fourth varistor are 561K-10D varistors.

[0017] The beneficial effects of the utility model are embodied in: by adding an isolation transformer, a varistor, a discharge tube and a capacitor to the lightning protection circuit, a variety of protection devices are combined with the isolation transformer, the value is first quickly reduced by the varistor and the discharge tube to prevent the isolation transformer from being impacted by a large lightning current, and then the isolation transformer is connected to isolate the lightning surge, and the varistor and capacitor connected to the secondary side are used to further absorb the energy of the residual lightning current; the entire scheme improves the lightning protection performance through multi-device and multi-level lightning protection processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the specific implementation or the prior art description. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, each element or part is not necessarily drawn according to the actual scale.

[0019] Figure 1A circuit schematic diagram of a lightning protection circuit in a power lightning protection device provided by an embodiment of the utility model;

[0020] Figure 2 A circuit schematic diagram of a clamping circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0021] The following embodiments of the technical solution of the utility model are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and are therefore only used as examples, and cannot be used to limit the protection scope of the utility model.

[0022] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by technicians in the field to which the utility model belongs.

[0023] like Figure 1 As shown, the utility model provides a power supply lightning protection device, including a shell and a circuit board arranged in the shell, the circuit board is provided with a lightning protection circuit, a rectifier bridge and a switching power supply chip, characterized in that the lightning protection circuit includes a power input end, an isolation transformer, a power output end, a first discharge tube, a second discharge tube, a first varistor, a second varistor, a third varistor, a fourth varistor and a first capacitor;

[0024] The power input terminal is respectively connected to the primary side of the isolation transformer, the first varistor is connected between the L and N terminals of the power input terminal, the L terminal of the power input terminal is also connected to one end of the first discharge tube through the second varistor, the N terminal of the power input terminal is also connected to one end of the first discharge tube through the third varistor, and the other end of the first discharge tube is grounded;

[0025] The secondary side of the isolation transformer is respectively connected in parallel with the first capacitor and the fourth varistor, and the fourth varistor is also grounded through the second discharge tube. The secondary side of the isolation transformer is connected to the power output end, and the power output end is connected to the input end of the rectifier bridge. The output end of the rectifier bridge is connected to the switching power chip, and the switching power chip is further connected to an external monitoring device.

[0026] In this embodiment, the lightning protection circuit is partially integrated into the front end of the power supply to avoid affecting subsequent devices; the power input end is an AC interface of the mains;

[0027] The rectifier bridge adopts a surface-mount rectifier module; the first varistor, the second varistor, the third varistor and the fourth varistor adopt 561K-10D varistors; the first capacitor is represented by C1; the discharge tube can also be understood as a discharge gap, and the two discharge gaps are different based on their positions and functions. The former adopts a switch-type discharge gap, and the latter adopts a voltage-limiting discharge gap. The first discharge tube is represented by G1, the first varistor is represented by MOV1, the second varistor is represented by MOV2, and so on; it should be noted that the above is only an example and is not intended to be limiting.

[0028] Furthermore, in order to improve the safety of the lightning protection circuit, the L end of the power input end is also connected to a wire-wound resistor R1 for protection; thus, even when the first varistor fails due to a short circuit, the wire-wound resistor R1 can act as a fuse.

[0029] Furthermore, in order to improve the power quality, a high-voltage filter capacitor is connected in parallel to the output end of the rectifier bridge.

[0030] At the same time, in order to protect the subsequent switching power supply chip, a clamping circuit is also connected between the rectifier bridge and the switching power supply chip.

[0031] Specifically, refer to Figure 2 , the clamping circuit includes a decoupling capacitor, a resistor R2, a capacitor C2 and a diode; the resistor R2 and the capacitor C2 are connected in parallel, and one of the common ends is grounded through the decoupling capacitor, the other common end is connected to the cathode of the diode, and the anode of the diode is connected to the switching power chip; the switching power chip is the power IC in the figure.

[0032] The utility model combines multiple protection devices with the isolation transformer by adding an isolation transformer, a varistor, a discharge tube and a capacitor into the lightning protection circuit. The value is first quickly reduced by the varistor and the discharge tube to prevent the isolation transformer from being impacted by a large lightning current. The isolation transformer is then connected to isolate the lightning surge, and the varistor and capacitor connected to the secondary side are used to further absorb the energy of the residual lightning current. The entire solution improves the lightning protection performance through multi-device and multi-level lightning protection processing.

[0033] Furthermore, in another embodiment, a signal surge protector is installed at the serial port of the monitoring device; this not only takes into account the protection of the power supply end, but also provides lightning protection for signal transmission.

[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the utility model, and they should all be included in the scope of the claims and specification of the utility model.

Claims

1. A power supply lightning protection device, comprising a housing and a circuit board arranged in the housing, wherein the circuit board is provided with a lightning protection circuit, a rectifier bridge and a switching power supply chip, Features , the lightning protection circuit includes a power input terminal, an isolation transformer, a power output terminal, a first discharge tube, a second discharge tube, a first varistor, a second varistor, a third varistor, a fourth varistor and a first capacitor; The power input terminal is respectively connected to the primary side of the isolation transformer, the first varistor is connected between the L and N terminals of the power input terminal, the L terminal of the power input terminal is also connected to one end of the first discharge tube through the second varistor, the N terminal of the power input terminal is also connected to one end of the first discharge tube through the third varistor, and the other end of the first discharge tube is grounded; The secondary side of the isolation transformer is respectively connected in parallel with the first capacitor and the fourth varistor, and the fourth varistor is also grounded through the second discharge tube. The secondary side of the isolation transformer is connected to the power output end, and the power output end is connected to the input end of the rectifier bridge. The output end of the rectifier bridge is connected to the switching power chip, and the switching power chip is further connected to an external monitoring device.

2. A power supply lightning protection device according to claim 1, Features The L end of the power input terminal is also connected to a wire-wound resistor R1 for protection.

3. A power supply lightning protection device according to claim 2, Features , a high-voltage filter capacitor is also connected in parallel to the output end of the rectifier bridge.

4. A power supply lightning protection device according to claim 1, Features A clamping circuit is also connected between the rectifier bridge and the switching power supply chip.

5. A power supply lightning protection device according to claim 4, Features The clamping circuit includes a decoupling capacitor, a resistor R2, a capacitor C2 and a diode; the resistor R2 and the capacitor C2 are connected in parallel, and one of the common ends is grounded through the decoupling capacitor, the other common end is connected to the cathode of the diode, and the anode of the diode is connected to the switching power supply chip.

6. A power supply lightning protection device according to any one of claims 1 to 5, Features ,The rectifier bridge adopts a surface-mount rectifier module.

7. A power supply lightning protection device according to claim 6, Features ,A signal surge protector is installed at the serial port of the monitoring device.

8. A power supply lightning protection device according to claim 6, Features The first varistor, the second varistor, the third varistor and the fourth varistor are 561K-10D varistors.

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