Intrinsic safety output Ethernet transmission circuit

Abstract

The invention relates to the field of explosion-proof electrical technology, and discloses an intrinsically safe output Ethernet transmission circuit, which comprises an Ethernet physical layer transceiver chip U6, a network transformer U7, an electrostatic protection diode D17, an electrostatic protection diode D18, voltage stabilizing diodes D13-16, capacitors C46-62, resistors R42-45, resistors R59-65, thick film resistors R74-77, fuses F1-4, a safety Y capacitor CY1, an inductor L2, a gas discharge tube TV1, a gas discharge tube TV2 and an RJ45 connector RJ1. The intrinsically safe output Ethernet transmission circuit provided by the invention realizes 3000V voltage isolation, has the characteristics of low cost and easiness in implementation, not only has strong anti-interference and lightning surge protection capabilities and stable transmission performance, but also is easy to calculate and check intrinsically safe parameters through multi-stage isolation and current-limiting and voltage-limiting protection, and has a wide application prospect. And multiple key problems in intrinsic safety Ethernet transmission are effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of explosion-proof electrical technology, and in particular to an intrinsically safe output Ethernet transmission circuit. Background Art

[0002] In environments with flammable and explosive hazards, such as the petrochemical industry and coal mining, the design of intrinsically safe Ethernet transmission circuits is crucial. In the past, network transformers, current-limiting resistors, and disposable fuses were commonly used to construct intrinsically safe circuits. Network transformers, with their electrical isolation, signal amplification, and common-mode rejection, are widely used in Ethernet transmission circuits. They effectively enhance signal transmission distance and stability, prevent damage when connecting devices with different voltages, and reduce common-mode radiation interference. Current-limiting resistors, based on Ohm's law, adjust their resistance to limit circuit current, preventing excessive current from damaging circuit components such as Zener diodes and LEDs. Disposable fuses melt when current increases abnormally, disconnecting the circuit and protecting downstream circuits and equipment from potential hazards such as short circuits. However, with the advancement and in-depth research of explosion-proof technology, network transformers, according to the latest explosion-proof standards and related technical specifications, pose safety risks in certain hazardous environments due to their inherent structure and operating principles, and are no longer suitable for use as isolation devices. This change has necessitated new design ideas and solutions for intrinsically safe Ethernet transmission circuits to meet the dual requirements of safety and functionality. Summary of the Invention

[0003] The present invention provides an intrinsically safe output Ethernet transmission circuit that achieves 3000V voltage isolation and is low-cost and easy to implement. Through multi-level isolation and current and voltage limiting protection, it not only has strong anti-interference and lightning surge protection capabilities and stable transmission performance, but also facilitates the calculation and verification of intrinsic safety parameters, effectively solving multiple key issues in intrinsically safe Ethernet transmission.

[0004] The present invention provides an intrinsically safe output Ethernet transmission circuit, including an Ethernet physical layer transceiver chip U6, a network transformer U7, an electrostatic protection diode D17, an electrostatic protection diode D18, voltage-stabilizing diodes D13-16, capacitors C46-62, resistors R42-45, resistors R59-65, thick-film resistors R74-77, fuses F1-4, a safety Y capacitor CY1, an inductor L2, a gas discharge tube TV1, a gas discharge tube TV2, and an RJ45 connector RJ1; Pin 24 of the Ethernet physical layer transceiver chip U6 is connected to one end of the resistor R64, and the other end of the resistor R64 is grounded. Pins 1, 9, and 19 of the Ethernet physical layer transceiver chip U6 are connected to one end of the capacitor C50, capacitor C51, and capacitor C52. Pin 6 of the Ethernet physical layer transceiver chip U6 is connected to one end of the capacitor C53 and capacitor C54. The other ends of the capacitors C50, C51, C52, C53, and C54 are all connected to pin 0 of the Ethernet physical layer transceiver chip U6 and grounded. Pin 21 of the Ethernet physical layer transceiver chip U6 is connected to one end of the electrostatic protection diode D17, one end of the resistor R42, one end of the capacitor C46, ​​and the network variable Pin 1 of the voltage transformer U7, pin 20 of the Ethernet physical layer transceiver chip U6 is connected to the other end of the electrostatic protection diode D17, one end of the resistor R43, one end of the capacitor C47, and pin 3 of the network transformer U7, pin 23 of the Ethernet physical layer transceiver chip U6 is connected to one end of the electrostatic protection diode D18, one end of the resistor R44, one end of the capacitor C48, and pin 6 of the network transformer U7, pin 22 of the Ethernet physical layer transceiver chip U6 is connected to the other end of the electrostatic protection diode D18, one end of the resistor R45, one end of the capacitor C49, and pin 8 of the network transformer U7, the other ends of the resistors R42~45D are all connected to the power supply, and the other ends of the capacitors C46~49 are all grounded; Pin 16 of the network transformer U7 is connected to one end of the capacitor C55, the other end of the capacitor C55 is connected to one end of the capacitor C56, the other end of the capacitor C56 is connected to one end of the fuse F1, the other end of the fuse F1 is connected to the cathode of the Zener diode D13, the anode of the Zener diode D14, and one end of the thick-film resistor R74, and the other end of the thick-film resistor R74 is connected to the first electrode of the gas discharge tube TV1 and pin 1 of the RJ45 connector RJ1; Pin 14 of the network transformer U7 is connected to one end of the capacitor C57, the other end of the capacitor C57 is connected to one end of the capacitor C58, the other end of the capacitor C58 is connected to one end of the fuse F2, the other end of the fuse F2 is connected to the anode of the Zener diode D13, the cathode of the Zener diode D14, and one end of the thick-film resistor R75, the other end of the back-mold resistor R75 is connected to the second electrode of the gas discharge tube TV1 and pin 2 of the RJ45 connector RJ1, and the common electrode of the gas discharge tube TV1 is grounded; Pin 11 of the network transformer U7 is connected to one end of the capacitor C59, the other end of the capacitor C59 is connected to one end of the capacitor C60, the other end of the capacitor C60 is connected to one end of the fuse F3, the other end of the fuse F3 is connected to the cathode of the Zener diode D15, the anode of the Zener diode D16, and one end of the thick-film resistor R76, and the other end of the thick-film resistor R76 is connected to the second electrode of the gas discharge tube TV2 and pin 3 of the RJ45 connector RJ1; Pin 9 of the network transformer U7 is connected to one end of the capacitor C61, the other end of the capacitor C61 is connected to one end of the capacitor C62, the other end of the capacitor C62 is connected to one end of the fuse F4, the other end of the fuse F4 is connected to the anode of the Zener diode D15, the cathode of the Zener diode D16, and one end of the thick-film resistor R77, the other end of the back-mold resistor R77 is connected to the first electrode of the gas discharge tube TV2 and pin 6 of the RJ45 connector RJ1, and the common electrode of the gas discharge tube TV2 is grounded; Pin 13 of the network transformer U7 is connected to one end of the resistor R60, the other end of the resistor R60 is connected to one end of the safety Y capacitor CY1, one end of the resistor R61, and one end of the resistor R62, the other end of the resistor R61 is connected to pins 4 and 5 of the RJ45 connector RJ1, the other end of the resistor R62 is connected to pins 7 and 8 of the RJ45 connector RJ1, the other end of the safety Y capacitor CY1 is connected to pin 0 of the RJ45 connector RJ1 and one end of the inductor L2, the other end of the inductor L2 is connected to one end of the resistor R65, and is connected to pins 9 and 11 of the RJ45 connector RJ1 and grounded, the other end of the resistor R65 is connected to one end of the resistor R59, the other end of the resistor R59 is connected to pin 10 of the RJ45 connector RJ1, and pin 12 of the RJ45 connector RJ1 is connected to the resistor R63.

[0005] Furthermore, the model of the Ethernet physical layer transceiver chip U6 is LAN8720Ai-CP-TR.

[0006] Furthermore, the model of the network transformer U7 is TRC9016NLE.

[0007] Furthermore, the electrostatic protection diode D17 and the electrostatic protection diode D18 are both of the type ULC3311CDN.

[0008] Furthermore, the models of the voltage stabilizing diodes D13-16 are all BZX384-B5V1,115.

[0009] Furthermore, the capacitance of the capacitors C46~49 is 10pF, the capacitance of the capacitor C54 is 10uF, the capacitance of the capacitors C50~52 and C53 is 100nF, the parameter identification of the capacitors C55~62 is 1nF±10%3kV, and the parameter identification of the safety Y capacitor CY1 is 10nF / 2KV.

[0010] Furthermore, the resistance values ​​of the resistors R42 to R45 are all 49.9 ohms, the resistance values ​​of the resistors R59 and R63 are all 560 ohms, the resistance values ​​of the resistors R60 to R62 are all 75 ohms, the resistance value of the resistor R65 is 10K ohms, and the resistance value of the resistor R64 is 12K ohms.

[0011] Furthermore, the parameter identifications of the thick film resistors R74-77 are all 10Ω±5%750mW.

[0012] Furthermore, the overcurrent protection value of the fuses F1-4 is 125 mA, and the inductance of the inductor L2 is 10 uH.

[0013] Furthermore, the models of the gas discharge tube TV1 and the gas discharge tube TV2 are both 3R090A-5S, and the RJ45 connector RJ1 is an RJ45 interface with an LED indicator light.

[0014] The beneficial effects of the present invention are: The intrinsically safe output Ethernet transmission circuit of the present invention adopts a hierarchical and comprehensive design composed of a PHY chip U6, a network transformer, an isolation capacitor, a current-limiting resistor, a disposable fuse and a TVS. While being able to quickly adapt to the latest explosion-proof requirements, it follows the principle of minor changes and no cost increase, effectively balancing safety and economy. Its stable transmission performance advantage ensures efficient and reliable transmission of Ethernet signals in hazardous environments such as flammable and explosive environments, thereby guaranteeing the continuity of data communications. Its high protection level and strong anti-interference capability enable it to fully resist interference and risks such as static electricity, surges, and overcurrent through multi-level protection components (such as transient voltage suppression of TVS tubes, overcurrent protection of current-limiting resistors and fuses, and electrical isolation supplementation of isolation capacitors), thus meeting the stringent safety standards of intrinsically safe circuits. Its low cost advantage is due to minor changes to the existing circuit structure and the selection of mature components. While achieving an upgrade in explosion-proof performance, it avoids the cost increase brought about by large-scale design adjustments. It is suitable for intrinsically safe environments such as petrochemicals and coal mining that have high requirements for safety and economy. It can quickly replace existing Ethernet network transmission circuits, making the product meet explosion-proof requirements and seize the market. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1This is a circuit diagram of the intrinsically safe output Ethernet transmission circuit of the present invention.

[0016] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0017] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0018] This invention is primarily used in the field of explosion-proof electrical technology, particularly in network communication equipment in explosive environments such as coal mines and petrochemicals. It achieves safe Ethernet signal transmission through intrinsically safe circuit design. Examples include flameproof power supplies, encapsulated power supplies, flameproof switches, and intrinsically safe substations.

[0019] like Figure 1 As shown, the present invention provides an intrinsically safe output Ethernet transmission circuit, including an Ethernet physical layer (PHY) transceiver chip U6, a network transformer U7, an electrostatic protection diode D17, an electrostatic protection diode D18, Zener diodes D13-16, capacitors C46-62, resistors R42-45, resistors R59-65, thick film resistors R74-77, fuses F1-4, a safety Y capacitor CY1, an inductor L2, a gas discharge tube TV1, a gas discharge tube TV2, and an RJ45 connector RJ1; Pin 24 of the Ethernet physical layer transceiver chip U6 is connected to one end of the resistor R64, and the other end of the resistor R64 is grounded. Pins 1, 9, and 19 of the Ethernet physical layer transceiver chip U6 are connected to one end of the capacitor C50, capacitor C51, and capacitor C52. Pin 6 of the Ethernet physical layer transceiver chip U6 is connected to one end of the capacitor C53 and capacitor C54. The other ends of the capacitors C50, C51, C52, C53, and C54 are all connected to pin 0 of the Ethernet physical layer transceiver chip U6 and grounded. Pin 21 of the Ethernet physical layer transceiver chip U6 is connected to one end of the electrostatic protection diode D17, one end of the resistor R42, one end of the capacitor C46, ​​and the network variable Pin 1 of the voltage transformer U7, pin 20 of the Ethernet physical layer transceiver chip U6 is connected to the other end of the electrostatic protection diode D17, one end of the resistor R43, one end of the capacitor C47, and pin 3 of the network transformer U7, pin 23 of the Ethernet physical layer transceiver chip U6 is connected to one end of the electrostatic protection diode D18, one end of the resistor R44, one end of the capacitor C48, and pin 6 of the network transformer U7, pin 22 of the Ethernet physical layer transceiver chip U6 is connected to the other end of the electrostatic protection diode D18, one end of the resistor R45, one end of the capacitor C49, and pin 8 of the network transformer U7, the other ends of the resistors R42~45D are all connected to the power supply, and the other ends of the capacitors C46~49 are all grounded; Pin 16 of the network transformer U7 is connected to one end of the capacitor C55, the other end of the capacitor C55 is connected to one end of the capacitor C56, the other end of the capacitor C56 is connected to one end of the fuse F1, the other end of the fuse F1 is connected to the cathode of the Zener diode D13, the anode of the Zener diode D14, and one end of the thick-film resistor R74, and the other end of the thick-film resistor R74 is connected to the first electrode of the gas discharge tube TV1 and pin 1 of the RJ45 connector RJ1; Pin 14 of the network transformer U7 is connected to one end of the capacitor C57, the other end of the capacitor C57 is connected to one end of the capacitor C58, the other end of the capacitor C58 is connected to one end of the fuse F2, the other end of the fuse F2 is connected to the anode of the Zener diode D13, the cathode of the Zener diode D14, and one end of the thick-film resistor R75, the other end of the back-mold resistor R75 is connected to the second electrode of the gas discharge tube TV1 and pin 2 of the RJ45 connector RJ1, and the common electrode of the gas discharge tube TV1 is grounded; Pin 11 of the network transformer U7 is connected to one end of the capacitor C59, the other end of the capacitor C59 is connected to one end of the capacitor C60, the other end of the capacitor C60 is connected to one end of the fuse F3, the other end of the fuse F3 is connected to the cathode of the Zener diode D15, the anode of the Zener diode D16, and one end of the thick-film resistor R76, and the other end of the thick-film resistor R76 is connected to the second electrode of the gas discharge tube TV2 and pin 3 of the RJ45 connector RJ1; Pin 9 of the network transformer U7 is connected to one end of the capacitor C61, the other end of the capacitor C61 is connected to one end of the capacitor C62, the other end of the capacitor C62 is connected to one end of the fuse F4, the other end of the fuse F4 is connected to the anode of the Zener diode D15, the cathode of the Zener diode D16, and one end of the thick-film resistor R77, the other end of the back-mold resistor R77 is connected to the first electrode of the gas discharge tube TV2 and pin 6 of the RJ45 connector RJ1, and the common electrode of the gas discharge tube TV2 is grounded; Pin 13 of the network transformer U7 is connected to one end of the resistor R60, the other end of the resistor R60 is connected to one end of the safety Y capacitor CY1, one end of the resistor R61, and one end of the resistor R62, the other end of the resistor R61 is connected to pins 4 and 5 of the RJ45 connector RJ1, the other end of the resistor R62 is connected to pins 7 and 8 of the RJ45 connector RJ1, the other end of the safety Y capacitor CY1 is connected to pin 0 of the RJ45 connector RJ1 and one end of the inductor L2, the other end of the inductor L2 is connected to one end of the resistor R65, and is connected to pins 9 and 11 of the RJ45 connector RJ1 and grounded, the other end of the resistor R65 is connected to one end of the resistor R59, the other end of the resistor R59 is connected to pin 10 of the RJ45 connector RJ1, and pin 12 of the RJ45 connector RJ1 is connected to the resistor R63.

[0020] In one embodiment, in the intrinsically safe output Ethernet transmission circuit provided by the present invention, the model of the Ethernet physical layer transceiver chip U6 is LAN8720Ai-CP-TR; the model of the network transformer U7 is TRC9016NLE; the model of the electrostatic protection diode D17 and the electrostatic protection diode D18 are both ULC3311CDN; the model of the voltage regulator diodes D13-16 are all BZX384-B5V1,115; In one embodiment, in the intrinsically safe output Ethernet transmission circuit provided by the present invention, the capacitance of the capacitors C46~49 is 10pF, the capacitance of the capacitor C54 is 10uF, the capacitance of the capacitors C50~52 and the capacitor C53 is 100nF, the parameter identification of the capacitors C55~62 is 1nF±10%3kV, and the parameter identification of the safety Y capacitor CY1 is 10nF / 2KV.

[0021] The resistance values ​​of the resistors R42~45 are all 49.9 ohms, the resistance values ​​of the resistors R59 and R63 are all 560 ohms, the resistance values ​​of the resistors R60~62 are all 75 ohms, the resistance value of the resistor R65 is 10K ohms, and the resistance value of the resistor R64 is 12K ohms; the parameter identifications of the thick film resistors R74~77 are all 10Ω±5%750mW.

[0022] In one embodiment, in the intrinsically safe output Ethernet transmission circuit provided by the present invention, the overcurrent protection value of the fuses F1-4 is 125mA, the inductance of the inductor L2 is 10uH; the model of the gas discharge tube TV1 and the gas discharge tube TV2 are both 3R090A-5S, and the RJ45 connector RJ1 is an RJ45 interface with an LED indicator.

[0023] The working principle of the intrinsically safe output Ethernet transmission circuit provided by the present invention is as follows: based on a physical layer protocol, the mutual conversion between digital signals and analog signals is realized through the protocol, thereby ensuring that data can be transmitted stably and reliably in various transmission media; at the same time, the circuit integrates an electrical isolation function, which can effectively isolate the electrical connections between different circuits to avoid the transmission of hazardous energy; the EMC protection capability can resist electromagnetic interference and ensure the integrity of signal transmission; combined with the current limiting and overcurrent protection mechanisms, the current in the circuit can be strictly controlled within a safe range to prevent danger caused by excessive current, thereby achieving safe Ethernet data transmission while meeting intrinsic safety requirements.

[0024] The intrinsically safe output Ethernet transmission circuit of the present invention achieves three levels of protection through anti-surge components with different parameters: (1) Model 3R090A-5S of the gas discharge tube TV1 and gas discharge tube TV2 is a ceramic gas discharge tube (GDT), which is mainly used for overvoltage protection in circuits. It is used for surge protection in power supplies, communication equipment and other fields, and can withstand high transient current shocks (such as lightning strikes and electrostatic discharge).

[0025] (2) The voltage regulator diodes D13 to D16 are model BZX384-B5V1,115, which are surface mount Zener (voltage regulator) diodes that limit the peak-to-peak value of the circuit to approximately 5.1V.

[0026] (3) The ESD protection diodes D17 and D18, model ULC3311CDN, are ESD protection diodes primarily used for static and surge protection of electronic equipment. Their primary purpose is to limit energy and protect the Ethernet physical layer transceiver chip U6, enabling it to function properly. In the intrinsically safe output Ethernet transmission circuit provided by the present invention, F1 is a one-time fuse with an overcurrent protection value of 125mA, and R74 is a resistor that limits the current in the circuit.

[0027] In this invention, network transformer U7 and capacitors C55 and C56 all provide electrical isolation, with a single capacitor rated at 3kV. Through its four-pronged mechanism of isolation, coupling, filtering, and matching, network transformer U7 addresses signal attenuation, electrical compatibility, and interference mitigation in long-distance transmission, fundamentally ensuring the high-speed and stable operation of modern Ethernet equipment. Capacitors C55 and C56 utilize their AC-passing, DC-blocking properties to completely block the DC voltage between upstream and downstream circuits when transmitting AC signals (such as audio and data pulses), preventing DC bias interference.

[0028] The Bob Smith circuit composed of the network transformer U7 and the resistor R75 in the present invention has the following functions: a. Common-mode noise filtering: A resistor-capacitor (RC) network provides a low-impedance discharge path for common-mode interference, reducing EMI radiation by approximately 10 dB and suppressing the impact of external electromagnetic interference on differential signals.

[0029] b. Surge protection: High-voltage capacitors (such as 1000pF / 2kV) can conduct transient high voltage during lightning strikes or electrostatic shocks, protecting the backend PHY chip.

[0030] c. Impedance matching: The 75Ω resistor matches the characteristic impedance of the transmission line to reduce signal reflections.

[0031] Based on the above circuit working principles and circuit characteristics, the intrinsically safe output Ethernet transmission circuit provided by the present invention can stably withstand 3000V voltage isolation and meet the stringent requirements of high voltage isolation; at the same time, it has the advantages of low cost and has been put into practical application, and can be put into use without high investment; through multi-level isolation and current limiting and voltage limiting protection design, a comprehensive safety protection system is formed to effectively avoid overcurrent and overvoltage risks in the circuit; its intrinsic safety parameters are easy to calculate and verify, which simplifies the circuit design and verification process; in addition, the circuit has strong anti-interference and lightning surge protection capabilities, can maintain stable operation in complex electromagnetic environments, and has stable and reliable transmission performance, ensuring efficient and continuous transmission of Ethernet signals, and can quickly replace existing Ethernet network transmission circuits, so that the product meets explosion-proof requirements, seizes the market, and comprehensively solves multiple key problems in the intrinsically safe output Ethernet transmission process, providing strong guarantees for safe communications in related fields.

[0032] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, apparatus, article, or method comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, apparatus, article, or method. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, apparatus, article, or method comprising the element.

[0033] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An intrinsically safe output Ethernet transmission circuit, characterized in that: Includes Ethernet physical layer transceiver chip U6, network transformer U7, electrostatic protection diode D17, electrostatic protection diode D18, Zener diodes D13~16, capacitors C46~62, resistors R42~45, resistors R59~65, thick film resistors R74~77, fuses F1~4, safety Y capacitor CY1, inductor L2, gas discharge tube TV1, gas discharge tube TV2, and RJ45 connector RJ1; Pin 24 of the Ethernet physical layer transceiver chip U6 is connected to one end of the resistor R64, and the other end of the resistor R64 is grounded. Pins 1, 9, and 19 of the Ethernet physical layer transceiver chip U6 are connected to one end of the capacitor C50, capacitor C51, and capacitor C52. Pin 6 of the Ethernet physical layer transceiver chip U6 is connected to one end of the capacitor C53 and capacitor C54. The other ends of the capacitors C50, C51, C52, C53, and C54 are all connected to pin 0 of the Ethernet physical layer transceiver chip U6 and grounded. Pin 21 of the Ethernet physical layer transceiver chip U6 is connected to one end of the electrostatic protection diode D17, one end of the resistor R42, one end of the capacitor C46, ​​and the network variable Pin 1 of the voltage transformer U7, pin 20 of the Ethernet physical layer transceiver chip U6 is connected to the other end of the electrostatic protection diode D17, one end of the resistor R43, one end of the capacitor C47, and pin 3 of the network transformer U7, pin 23 of the Ethernet physical layer transceiver chip U6 is connected to one end of the electrostatic protection diode D18, one end of the resistor R44, one end of the capacitor C48, and pin 6 of the network transformer U7, pin 22 of the Ethernet physical layer transceiver chip U6 is connected to the other end of the electrostatic protection diode D18, one end of the resistor R45, one end of the capacitor C49, and pin 8 of the network transformer U7, the other ends of the resistors R42~45D are all connected to the power supply, and the other ends of the capacitors C46~49 are all grounded; Pin 16 of the network transformer U7 is connected to one end of the capacitor C55, the other end of the capacitor C55 is connected to one end of the capacitor C56, the other end of the capacitor C56 is connected to one end of the fuse F1, the other end of the fuse F1 is connected to the cathode of the Zener diode D13, the anode of the Zener diode D14, and one end of the thick-film resistor R74, and the other end of the thick-film resistor R74 is connected to the first electrode of the gas discharge tube TV1 and pin 1 of the RJ45 connector RJ1; Pin 14 of the network transformer U7 is connected to one end of the capacitor C57, the other end of the capacitor C57 is connected to one end of the capacitor C58, the other end of the capacitor C58 is connected to one end of the fuse F2, the other end of the fuse F2 is connected to the anode of the Zener diode D13, the cathode of the Zener diode D14, and one end of the thick-film resistor R75, the other end of the back-mold resistor R75 is connected to the second electrode of the gas discharge tube TV1 and pin 2 of the RJ45 connector RJ1, and the common electrode of the gas discharge tube TV1 is grounded; Pin 11 of the network transformer U7 is connected to one end of the capacitor C59, the other end of the capacitor C59 is connected to one end of the capacitor C60, the other end of the capacitor C60 is connected to one end of the fuse F3, the other end of the fuse F3 is connected to the cathode of the Zener diode D15, the anode of the Zener diode D16, and one end of the thick-film resistor R76, and the other end of the thick-film resistor R76 is connected to the second electrode of the gas discharge tube TV2 and pin 3 of the RJ45 connector RJ1; Pin 9 of the network transformer U7 is connected to one end of the capacitor C61, the other end of the capacitor C61 is connected to one end of the capacitor C62, the other end of the capacitor C62 is connected to one end of the fuse F4, the other end of the fuse F4 is connected to the anode of the Zener diode D15, the cathode of the Zener diode D16, and one end of the thick-film resistor R77, the other end of the back-mold resistor R77 is connected to the first electrode of the gas discharge tube TV2 and pin 6 of the RJ45 connector RJ1, and the common electrode of the gas discharge tube TV2 is grounded; Pin 13 of the network transformer U7 is connected to one end of the resistor R60, the other end of the resistor R60 is connected to one end of the safety Y capacitor CY1, one end of the resistor R61, and one end of the resistor R62, the other end of the resistor R61 is connected to pins 4 and 5 of the RJ45 connector RJ1, the other end of the resistor R62 is connected to pins 7 and 8 of the RJ45 connector RJ1, the other end of the safety Y capacitor CY1 is connected to pin 0 of the RJ45 connector RJ1 and one end of the inductor L2, the other end of the inductor L2 is connected to one end of the resistor R65, and is connected to pins 9 and 11 of the RJ45 connector RJ1 and grounded, the other end of the resistor R65 is connected to one end of the resistor R59, the other end of the resistor R59 is connected to pin 10 of the RJ45 connector RJ1, and pin 12 of the RJ45 connector RJ1 is connected to the resistor R63.

2. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The model of the Ethernet physical layer transceiver chip U6 is LAN8720Ai-CP-TR.

3. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The model of the network transformer U7 is TRC9016NLE.

4. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The electrostatic protection diode D17 and the electrostatic protection diode D18 are both of model ULC3311CDN.

5. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The models of the voltage stabilizing diodes D13 to D16 are all BZX384-B5V1,115.

6. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The capacitance of the capacitors C46~49 is 10pF, the capacitance of the capacitor C54 is 10uF, the capacitance of the capacitors C50~52 and C53 is 100nF, the parameter markings of the capacitors C55~62 are 1nF±10%3kV, and the parameter marking of the safety Y capacitor CY1 is 10nF / 2KV.

7. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The resistance values ​​of the resistors R42 to R45 are all 49.9 ohms, the resistance values ​​of the resistors R59 and R63 are all 560 ohms, the resistance values ​​of the resistors R60 to R62 are all 75 ohms, the resistance value of the resistor R65 is 10K ohms, and the resistance value of the resistor R64 is 12K ohms.

8. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The parameter markings of the thick film resistors R74-77 are all 10Ω±5%750mW.

9. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The overcurrent protection value of the fuses F1-4 is 125 mA, and the inductance of the inductor L2 is 10 uH.

10. The intrinsically safe output Ethernet transmission circuit according to claim 1, characterized in that: The gas discharge tube TV1 and the gas discharge tube TV2 are both of model 3R090A-5S, and the RJ45 connector RJ1 is an RJ45 interface with an LED indicator light.

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