A network port lightning protection circuit

Abstract

The invention provides a lightning protection circuit used for an internet port. The lightning protection circuit is arranged on a PCB which comprises a non-lightning-protection circuit; the lightning protection circuit used for the internet port comprises a first-stage line which is in termination between an RJ45 connector and a network isolation transformer, and a second-stage line which is in termination between the network isolation transformer and a network chip, wherein a transformer coil between the network isolation transformer and the RJ45 connector is defined as a primary coil; a transformer coil between the network isolation transformer and the network chip is defined as a secondary coil; the lightning protection circuit used for the internet port also comprises a first routing line group which is formed by the first-stage line in a connecting way and a second routing line group which is formed by the second-stage line in a connecting way, wherein the spacings between the first routing line group and routing lines on the non-lightning-protection circuit on the PCB are set to be 60mil. By adoption of the lightning protection circuit used for the internet port, the port lightning protection test requirement of an unshielded balance signal of a common mode 2kV and a differential mode 1kV can be satisfied through an IEC61000-4-5 or GB17626.5 standard; and therefore, the adopted devices are relatively small in number, and the occupied space is relatively small.

Description

technical field [0001] The invention relates to the technical field of circuits, and more specifically, to a network port lightning protection circuit and method. Background technique [0002] The currently used network port lightning protection circuit and its RJ45 interface device are based on adding a bidirectional transient voltage regulator TVS tube or discharge tube device, and applying the lightning protection circuit scheme on a printed circuit board (PCB). However, this kind of network lightning protection circuit basically requires a lot of devices, and in order to ensure the lightning protection effect and network transmission performance, it is usually necessary to use gas discharge tubes, TVS tubes, diodes, resistors and other devices, and the number of devices used Many, large volume, need to occupy a large proportion of the board space, the cost is quite expensive, more importantly, because of the large number of devices used in this lightning protection circu...

AI Technical Summary

Problems solved by technology

However, this kind of network lightning protection circuit basically requires a lot of devices, and in order to ensure the lightning protection effect and network transmission performance, it is usually necessary to use gas discharge tubes, TVS tubes, diodes, resistors and other devices, and the number of devices used Many, large volume, need to occupy a large proportion of the board space, the cost is quite expensive, more importantly, because of the large number of devices used in this lightning protection circuit, the size of the lightning protection devices used is quite large, and it is impossible to design in many occasions On the motherboard or on the NIC

[0003] In the existing lightning protection scheme, devices such as transient voltage regulators (TVS tubes) and diodes are directly applied to the network signal lines, and the two resistors connected in series on each network signal line will cause a huge loss in the performance of the gigabit network. Attenuation, affecting network transmission performance

When using this lightning protection circuit on a Gigabit network, the TVS tube is directly applied to the network signal transmission line. Due to the very large junction capacitance of the TVS tube, and the two resistors connected in series on each network signal line and a professional lightning protection IC, Both will cause a great attenuation of gigabit network performance and affect network transmission performance. At the same time, professional lightning protection ICs are expensive, resulting in high cost of lightning protection solutions

[0004] In summary, the existing lightning protection schemes use many devices and are quite expensive. The lightning protection devices used are relatively large in size and cannot be designed on the motherboard or network card in many occasions. It is necessary to independently design the lightning protection inside the chassis. circuit, or by using an external lightning protection method outside the chassis, but this method is also expensive, bulky, unreliable and inconvenient to assemble and use, and the excessive insertion loss of network signals will affect the quality of network transmission

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