Differential interface protection circuit suitable for RS422 or RS485 communication

A technology of protection circuit and differential interface, applied in the field of RS422 or RS485 communication, can solve problems such as communication interface damage, achieve low cost, improve protection effect, and achieve the effect of triple protection

Inactive Publication Date: 2019-04-12
XIAN MICROELECTRONICS TECH INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] At present, the mainstream RS422 or RS485 communication products on the market usually use transient suppression diodes for protection on their interfaces, which have a certain anti-interference ability. However, in some complex electrical systems, due to the harsh electromagnetic environment, they will still cause damage to the communication interface.

Method used

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  • Differential interface protection circuit suitable for RS422 or RS485 communication

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Embodiment Construction

[0019] The present invention is described in further detail below in conjunction with accompanying drawing:

[0020] see figure 1 As shown, the gas discharge tube Q1 is connected between the first signal terminal and the second signal terminal, the gas discharge tube Q2 and the gas discharge tube Q3 are arranged in series at both ends of the gas discharge tube Q1, and are arranged near the outside of the board. The discharge tube Q2 and the gas discharge tube Q3 are grounded; the models of the gas discharge tube Q1, the gas discharge tube Q2 and the gas discharge tube Q3 are all BK2RN090L-8.

[0021] The transient suppression diode T1 is connected between the first signal terminal and the second signal terminal, and is set close to the inside of the board, and its model is SA5.0CA.

[0022] The varistor Y1 and the varistor Y2 are connected in series and connected between the first signal terminal and the second signal terminal, and the varistor Y1 and the varistor Y2 are loca...

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Abstract

The invention discloses a differential interface protection circuit suitable for RS422 or RS485 communication, which comprises a first signal terminal, a second signal terminal, a first protection circuit and a second protection circuit. A gas discharge tube Q1 of the first protection circuit is connected between the first signal terminal and the second signal terminal, and a gas discharge tube Q2and a gas discharge tube Q3 are arranged at both ends of the gas discharge tube Q1 in series and close to the outside of a board, and the part between the gas discharge tube Q2 and the gas dischargetube Q3 is grounded. The second protection circuit adopts a transient suppression diode T1, which is connected between the first signal terminal and the second signal terminal, and is arranged close to the board. The first signal terminal is provided with a current limiting resistor R1, and the second signal terminal is provided with a current limiting resistor R2. The current limiting resistor R1and the current limiting resistor R2 are arranged between the first protection circuit and the second protection circuit. Dual protection of the interface is improved, and the interface security of the product is improved.

Description

technical field [0001] The invention belongs to the field of RS422 or RS485 communication, and relates to a differential interface protection circuit suitable for RS422 or RS485 communication. Background technique [0002] At present, the mainstream RS422 or RS485 communication products on the market usually use transient suppression diodes for protection on their interfaces, which have a certain anti-interference ability. However, in some complex electrical systems, due to the harsh electromagnetic environment, they will still cause damage to the communication interface. . Contents of the invention [0003] The purpose of the present invention is to overcome the shortcoming of above-mentioned prior art, provide a kind of differential interface protection circuit that is applicable to RS422 or RS485 communication, realize the double protection of interface, can be applied to the computer product that uses RS422 or RS485 communication interface, improve the safety of produc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H9/04H02H9/06
Inventor 李卫国侯建华
Owner XIAN MICROELECTRONICS TECH INST
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