Circuit for improving interference resistance of network port and inhibiting radiation disturbance
By combining ESD protection diodes, common-mode inductors, and network transformers at the network port, the problems of poor network port protection and high cost were solved, enabling stable operation of the equipment in extreme environments and improving electromagnetic compatibility.
Patent Information
- Application Number
- CN202423009591.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-06
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2034-12-06
AI Technical Summary
Existing network port protection methods are ineffective in extreme environments, costly, and cannot completely protect against lightning strikes and ESD, making equipment prone to damage in harsh environments. Cost control becomes a problem, especially in large-scale production.
The circuit design employs a combination of ESD protection diodes, common-mode inductors, and a network transformer. The ESD protection diodes absorb transient voltages, the common-mode inductors suppress common-mode interference signals, and the network transformer isolates and converts signals, while increasing common-mode impedance matching to improve anti-interference capability.
It improves the equipment's stable operation in complex electromagnetic environments, reduces interference with surrounding equipment, lowers the complexity and cost of the equipment structure, and enhances electromagnetic compatibility.
Smart Images
Figure CN223527785U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of electromagnetic compatibility especially relates to a circuit that improves network mouth anti -interference and restrain radiation harassment. BACKGROUND
[0002] Electromagnetic compatibility (EMC) refers to the ability that equipment can work normally in electromagnetic environment and cannot cause unacceptable electromagnetic interference to other equipment. EMC test is the comprehensive evaluation of the interference size (EMI) and anti-interference ability (EMS) of electronic products in electromagnetic field, and is an important index for measuring product quality. EMC test is completed by professional test site and test instrument together, and ensures the accuracy and reliability of test result.
[0003] At present, for the electronic product with Ethernet interface (RJ45), the common network mouth protection technical scheme mainly includes external protection equipment and high-specification isolation transformer. Since in the EMC certification process, the network circuit needs to be tested for radiation and anti-interference to ensure that the equipment will not interfere with the surrounding electronic equipment and can work normally in complex electromagnetic environment. The external protection equipment may not fully meet the strict standard requirements in some cases; the isolation transformer can reduce electromagnetic interference to a certain extent, but its cost is high, and in the face of extreme environment (such as lightning, ESD, etc.), the protection effect is limited and the hardware cost is increased. Even if a high-specification isolation transformer is used, it cannot completely resist lightning and ESD and other extreme conditions, resulting in that the equipment is easily damaged in harsh environment, especially in the case of large-scale production, cost control becomes a big problem. SUMMARY
[0004] The utility model provides a kind of circuit that improves network mouth anti-interference and restrain radiation harassment, to solve the problem of the protection effect of the existing network mouth protection means is poor, high cost.
[0005] The utility model provides a kind of circuit that improves network mouth anti-interference and restrain radiation harassment, including the ESD protection tube group for absorbing transient voltage, the common mode inductance group for inhibiting common mode interference signal and network transformer, the input end of the ESD protection tube group is connected with network end interface, the output end of the ESD protection tube group is connected with the input end of the common mode inductance group, the output end of the common mode inductance group is connected with the input end of the network transformer, the output end of the network transformer is connected with chip.
[0006] As a further improvement of the utility model, the ESD protection tube group includes protection diode D1, protection diode D2, protection diode D3 and protection diode D4, one end of protection diode D1 is connected with the 1 pin of network end interface, the other end of protection diode D1 is connected with the 2 pin of network end interface, one end of protection diode D2 is connected with the 4 pin of network end interface, the other end of protection diode D2 is connected with the 5 pin of network end interface, one end of protection diode D3 is connected with the 3 pin of network end interface, the other end of protection diode D3 is connected with the 6 pin of network end interface, one end of protection diode D4 is connected with the 7 pin of network end interface, the other end of protection diode D4 is connected with the 8 pin of network end interface.
[0007] As a further improvement of the utility model, the ESD protection tube group adopts TVS diode.
[0008] As a further improvement of the utility model, the common mode inductance group includes common mode inductance TL1, common mode inductance TL2, common mode inductance TL3 and common mode inductance TL4, the 1 pin of common mode inductance TL1 is connected with one end of protection diode D1, the 2 pin of common mode inductance TL1 is connected with the other end of protection diode D1, the 1 pin of common mode inductance TL2 is connected with one end of protection diode D2, the 2 pin of common mode inductance TL2 is connected with the other end of protection diode D2, the 1 pin of common mode inductance TL3 is connected with one end of protection diode D3, the 2 pin of common mode inductance TL3 is connected with the other end of protection diode D3, the 1 pin of common mode inductance TL4 is connected with one end of protection diode D4, the 2 pin of common mode inductance TL4 is connected with the other end of protection diode D4.
[0009] As a further improvement of the utility model, the 4 pin of common mode inductance TL1 is connected with the 13 pin of network transformer, the 3 pin of common mode inductance TL1 is connected with the 14 pin of network transformer, the 4 pin of common mode inductance TL2 is connected with the 16 pin of network transformer, the 3 pin of common mode inductance TL2 is connected with the 17 pin of network transformer, the 4 pin of common mode inductance TL3 is connected with the 19 pin of network transformer, the 3 pin of common mode inductance TL3 is connected with the 20 pin of network transformer, the 4 pin of common mode inductance TL4 is connected with the 22 pin of network transformer, the 3 pin of common mode inductance TL4 is connected with the 23 pin of network transformer.
[0010] As a further improvement of the utility model, the 1-12 pin of network transformer is connected with the chip respectively.
[0011] As a further improvement of the utility model, one end of the 15th pin of the network transformer is connected with the resistor R1, one end of the 18th pin of the network transformer is connected with the resistor R2, one end of the 21st pin of the network transformer is connected with the resistor R3, one end of the 24th pin of the network transformer is connected with the resistor R4, the other end of the resistor R1, the other end of the resistor R2, the other end of the resistor R3 and the other end of the resistor R4 are all connected with one end of the capacitor C1, and the other end of the capacitor C1 is grounded.
[0012] The utility model discloses the beneficial effect is: the utility model scheme is from the protection of ethernet entrance, through the effective combination of ESD protection diode and common mode inductance, improve the anti -interference ability of equipment, ensure stable operation under complex electromagnetic environment, reduce the interference to surrounding equipment, improve the electromagnetic compatibility of overall system. BRIEF DESCRIPTION OF DRAWINGS
[0013] Figure 1 It is the specific connection diagram of the utility model circuit. CONCRETE IMPLEMENTING METHOD
[0014] In order to make the purpose, technical scheme and advantage of the utility model more clear and obvious, the following combines the drawing and example, and further detailedly explains the utility model.
[0015] As Figure 1 The utility model discloses a kind of circuit for improving network mouth anti-interference and inhibiting radiation disturbance, including ESD protection tube group for absorbing transient voltage, common mode inductance group for inhibiting common mode interference signal and network transformer, the input end of the ESD protection tube group is connected with network end interface, the output end of the ESD protection tube group is connected with the input end of the common mode inductance group, the output end of the common mode inductance group is connected with the input end of the network transformer, and the output end of the network transformer is connected with chip.
[0016] As an embodiment of the utility model, the ESD protection tube group includes protection diode D1, protection diode D2, protection diode D3 and protection diode D4, one end of the protection diode D1 is connected with the 1st pin of network end interface, the other end of the protection diode D1 is connected with the 2nd pin of network end interface, one end of the protection diode D2 is connected with the 4th pin of network end interface, the other end of the protection diode D2 is connected with the 5th pin of network end interface, one end of the protection diode D3 is connected with the 3rd pin of network end interface, the other end of the protection diode D3 is connected with the 6th pin of network end interface, one end of the protection diode D4 is connected with the 7th pin of network end interface, and the other end of the protection diode D4 is connected with the 8th pin of network end interface.
[0017] As another embodiment of the utility model, the ESD protection tube group adopts TVS diode.
[0018] As another embodiment of the utility model, the common mode inductance group includes common mode inductance TL1, common mode inductance TL2, common mode inductance TL3 and common mode inductance TL4, the 1 pin of common mode inductance TL1 is connected with one end of protection diode D1, the 2 pin of common mode inductance TL1 is connected with the other end of protection diode D1, the 1 pin of common mode inductance TL2 is connected with one end of protection diode D2, the 2 pin of common mode inductance TL2 is connected with the other end of protection diode D2, the 1 pin of common mode inductance TL3 is connected with one end of protection diode D3, the 2 pin of common mode inductance TL3 is connected with the other end of protection diode D3, the 1 pin of common mode inductance TL4 is connected with one end of protection diode D4, and the 2 pin of common mode inductance TL4 is connected with the other end of protection diode D4.
[0019] As another embodiment of the utility model, the 4 pin of common mode inductance TL1 is connected with the 13 pin of network transformer, the 3 pin of common mode inductance TL1 is connected with the 14 pin of network transformer, the 4 pin of common mode inductance TL2 is connected with the 16 pin of network transformer, the 3 pin of common mode inductance TL2 is connected with the 17 pin of network transformer, the 4 pin of common mode inductance TL3 is connected with the 19 pin of network transformer, the 3 pin of common mode inductance TL3 is connected with the 20 pin of network transformer, the 4 pin of common mode inductance TL4 is connected with the 22 pin of network transformer, and the 3 pin of common mode inductance TL4 is connected with the 23 pin of network transformer.
[0020] As another embodiment of the utility model, the 1-12 pin of network transformer is connected with the chip respectively.
[0021] As another embodiment of the utility model, the 15 pin of network transformer is connected with one end of resistance R1, the 18 pin of network transformer is connected with one end of resistance R2, the 21 pin of network transformer is connected with one end of resistance R3, the 24 pin of network transformer is connected with one end of resistance R4, the other end of resistance R1, the other end of resistance R2, the other end of resistance R3 and the other end of resistance R4 are all connected with one end of capacitor C1, and the other end of capacitor C1 is grounded.
[0022] The utility model provides a kind of circuit for improving network mouth anti-interference and inhibiting radiation disturbance, for improving RJ45 network mouth anti-interference performance and inhibiting network mouth radiation disturbance this technical field, specifically cover EMC protection circuit and inhibiting circuit etc. with network mouth related aspects.
[0023] The utility model discloses hardware circuit design, increase the ESD protection pipe group and common mode inductance group between the network interface and the network transformer.
[0024] The working principle of the circuit is that the signal entering through the network interface is a differential signal based on the Ethernet standard (such as IEEE802.3). When an external electrostatic discharge interference signal enters the device through the RJ45 interface, the protection diodes D1, D2, D3 and D4 have a specific clamping voltage. When the input voltage exceeds this value, the diode will quickly conduct, clamping the excessive voltage within a safe range. The signal processed by the ESD protection tube group enters the common mode inductance group. When a common mode interference signal enters, the common mode inductors TL1, TL2, TL3 and TL4 will generate currents with the same direction on the two wires. These currents will generate a superimposed magnetic field in the core of the common mode inductor, causing the core to be magnetized. Due to the high inductance of the common mode inductor, the superimposed magnetic field forms a high impedance path, effectively preventing the common mode interference signal from passing through. As a result, the common mode interference signal is attenuated or reflected back, and does not reach the backend circuit, reducing the impact on the subsequent circuit. Finally, the signal is transmitted to the chip (PHY) through the network transformer, realizing signal isolation and conversion. In the circuit, the circuit composed of resistors R1, R2, R3, R4 and capacitor C1 provides a 150Ω common mode impedance matching for the differential line pair, providing a low impedance return path for the common mode signal, improving the anti-interference ability of the device. The common mode inductance group not only suppresses the common mode interference signal entering the device, but also reduces the radiation interference of the device to the outside world. By replacing different models of common mode inductors, the common mode interference suppression capability can be further improved, thereby improving the radiation problem of the EMC protection circuit device.
[0025] During the electrostatic discharge (ESD) test on the Ethernet interface (RJ45) of the test device (EUT), it was found that the EUT appeared gray screen and dead machine phenomenon, and needed to be manually restarted to restore normal work. After adding the ESD protection tube group between the differential signal lines of the RJ45 interface, the instantaneous high voltage generated by the electrostatic discharge is absorbed, and the protection effect of the EUT against electrostatic discharge (ESD) is enhanced.
[0026] In the low frequency radiation emission test, the Ethernet interface (RJ45) of the tested equipment (EUT) is a high-speed signal interface with strong electromagnetic field radiation interference, and when the test is carried out, the external network cable presents an antenna effect to amplify the electromagnetic field radiation interference. In this case, the increase of the radiation field strength causes the radiation to exceed the standard; after the 90Ω common mode inductor group dedicated to the gigabit network port is added to the differential signal line of the RJ45 interface, the common mode impedance of the differential signal is improved, thereby suppressing the electromagnetic wave generated by the high-speed signal line from radiating outward.
[0027] The utility model scheme protects from the Ethernet entrance, and the protection is more thorough, does not need the external protection equipment, simplifies the equipment structure, improves the protection effect, can select the conventional isolation transformer, and the component selection range is loose, and the cost is reduced, through the effective combination of ESD protection diode and common mode inductor, the anti-interference ability of the equipment is improved, and the stable operation under the complex electromagnetic environment is ensured, the equipment is smaller to the outside radiation interference signal, reduces the interference to the surrounding equipment, improves the electromagnetic compatibility of the whole system.
[0028] The above content is the further detailed description of the utility model made in combination with the specific preferred implementation mode, and the specific implementation of the utility model cannot be limited to these descriptions. For ordinary skilled persons in the technical field to which the utility model belongs, on the premise of not departing from the utility model concept, a plurality of simple deductions or replacements can be made, and all should be regarded as belonging to the protection scope of the utility model.
Claims
1. A circuit for improving network port anti-interference and suppressing radiated interference, characterized in that, The application relates to a network transformer, which comprises an ESD protection tube group for absorbing transient voltage, a common-mode inductor group for suppressing common-mode interference signals and the network transformer, wherein the input end of the ESD protection tube group is connected with a network interface, the output end of the ESD protection tube group is connected with the input end of the common-mode inductor group, the output end of the common-mode inductor group is connected with the input end of the network transformer, and the output end of the network transformer is connected with a chip.
2. The circuit for improving the anti-interference and suppressing the radiation disturbance of the network port according to claim 1, characterized in that, The ESD protection tube group comprises protection diodes D1, D2, D3 and D4, one end of the protection diode D1 is connected with a 1 pin of the network interface, the other end of the protection diode D1 is connected with a 2 pin of the network interface, one end of the protection diode D2 is connected with a 4 pin of the network interface, the other end of the protection diode D2 is connected with a 5 pin of the network interface, one end of the protection diode D3 is connected with a 3 pin of the network interface, the other end of the protection diode D3 is connected with a 6 pin of the network interface, one end of the protection diode D4 is connected with a 7 pin of the network interface, and the other end of the protection diode D4 is connected with a 8 pin of the network interface.
3. The circuit for improving the anti-interference and suppressing the radiation disturbance of the network port according to claim 1, characterized in that, The ESD protection tube group adopts a TVS diode.
4. The circuit for improving the anti-interference and suppressing the radiation disturbance of the network port according to claim 2, characterized in that, The common-mode inductor group comprises common-mode inductors TL1, TL2, TL3 and TL4, a 1 pin of the common-mode inductor TL1 is connected with one end of the protection diode D1, a 2 pin of the common-mode inductor TL1 is connected with the other end of the protection diode D1, a 1 pin of the common-mode inductor TL2 is connected with one end of the protection diode D2, a 2 pin of the common-mode inductor TL2 is connected with the other end of the protection diode D2, a 1 pin of the common-mode inductor TL3 is connected with one end of the protection diode D3, a 2 pin of the common-mode inductor TL3 is connected with the other end of the protection diode D3, a 1 pin of the common-mode inductor TL4 is connected with one end of the protection diode D4, and a 2 pin of the common-mode inductor TL4 is connected with the other end of the protection diode D4.
5. The circuit for improving the anti-interference and suppressing the radiation disturbance of the network port according to claim 4, characterized in that, A 4 pin of the common-mode inductor TL1 is connected with a 13 pin of the network transformer, a 3 pin of the common-mode inductor TL1 is connected with a 14 pin of the network transformer, a 4 pin of the common-mode inductor TL2 is connected with a 16 pin of the network transformer, a 3 pin of the common-mode inductor TL2 is connected with a 17 pin of the network transformer, a 4 pin of the common-mode inductor TL3 is connected with a 19 pin of the network transformer, a 3 pin of the common-mode inductor TL3 is connected with a 20 pin of the network transformer, a 4 pin of the common-mode inductor TL4 is connected with a 22 pin of the network transformer, and a 3 pin of the common-mode inductor TL4 is connected with a 23 pin of the network transformer.
6. The circuit for improving the anti-interference and suppressing the radiation disturbance of the network port according to claim 1, characterized in that, 1-12 pins of the network transformer are connected with the chip respectively.
7. The circuit for improving the anti-interference and suppressing the radiation disturbance of the network port according to claim 1, characterized in that, The 15th pin of the network transformer is connected with one end of the resistor R1, the 18th pin of the network transformer is connected with one end of the resistor R2, the 21st pin of the network transformer is connected with one end of the resistor R3, the 24th pin of the network transformer is connected with one end of the resistor R4, the other end of the resistor R1, the other end of the resistor R2, the other end of the resistor R3 and the other end of the resistor R4 are all connected with one end of the capacitor C1, and the other end of the capacitor C1 is grounded.