CN204733134U - Network signal noise filtering circuit - Google Patents

Abstract

The utility model discloses a network signal noise filtering circuit, which comprises a processing circuit arranged on a circuit board, wherein a circuit channel is connected between a first connecting end and a second connecting end of the processing circuit, a common mode inductance unit is connected in parallel between any two adjacent circuit channels, a coupling capacitor is respectively connected in series on each circuit channel at one side adjacent to the common mode inductance unit, an autotransformer is respectively connected in parallel between any two adjacent circuit channels, electromagnetic waves or noise and the like mixed in network signals transmitted in each circuit channel can be filtered, the processing circuit can carry out grounding circuit design by respectively connecting a first wiring and a second wiring which are extended through the connection of the autotransformer, a resistor, a first capacitor and a second capacitor on the circuit board are respectively connected in series, so as to be applied to the existing circuit board, and electronic parts on the circuit board do not need to be matched to change the circuit layout, the purpose of reducing the production cost is achieved, and the practicability and the applicability are better.

Description

Network signal noise filter circuit

technical field

The utility model relates to a network signal noise filtering circuit, especially a circuit design in which a processing circuit can be connected in series with a resistance on a circuit board, a first capacitor and a second capacitor through an autotransformer to be grounded, so as to be applied to the existing The circuit board achieves the purpose of reducing the production cost and is more practical and applicable.

Background technique

Nowadays, with the rapid development of computer technology, the development trend of its computer is also moving towards the direction of powerful computing function, fast speed and small size. Because network communication technology is also developing rapidly and vigorously, it brings people's life, study, work and leisure into another It is a new realm that is different from the past, so that people can transmit the required real-time information, advertisements, or e-mails to each other through network communication, and at the same time search for various information, instant messaging or online games through the network, allowing people to communicate with The relationship between networks is more intense and inseparable.

In addition, two methods of cable connection and wireless transmission are used to transmit data in the network. The cable connection technology needs to be equipped with a network connector. As the network is used more and more widely, the data capacity of network transmission is also increasing. , from the early 10Mbps, 100Mbps and 1Gbps, and even the optical fiber network transmission speed introduced now can reach more than 10Gbps. or surges, the electronic components and network chips on the processing circuit will be damaged due to instantaneous high voltage or surges, resulting in unstable, interrupted or inaccessible network signal transmission, and even damage to the circuit board connected to the network chip. Or electronic devices (such as computer hosts or hubs, etc.) are all faulted or damaged by the impact of instantaneous high voltage or surge; the types of general networks can be roughly divided into local area networks, metropolitan networks, wide area networks, and wireless networks according to the geographical scope covered. Network and Internet, etc., and in the process of network signal transmission, it is easy to be affected by the interference of electromagnetic waves or noise from surrounding electronic parts, resulting in unstable network signal transmission, and the general practice is to set filter elements inside the network connector to The network signal is filtered to reduce the interference of electromagnetic waves and noise.

In the current network signal processing circuit, in order to prevent instantaneous high voltage or surge damage to the network chip and circuit board, some manufacturers install multiple transformers in the network connector, as shown in Figure 4, in which the lightning protection module A The transformer A1 has a primary side coil A11 and a secondary side coil A12, and a resistor A2 and a first capacitor A3 are respectively connected in series at the center tap A121 of the secondary side coil A12 and then connected to the ground terminal A31, and the primary side coil The middle tap A111 of A11 is connected in series with the second capacitor A4 and then connected to the ground terminal A41. When high voltage or surge occurs during network signal transmission, the instantaneous high voltage and surge can be eliminated through the coupling of transformer A1. The voltage is lowered, and transmitted to the ground terminal A31 through each resistor A2 and the first capacitor A3 for exclusion, so that high voltage or surge will not be transmitted to the network chip to avoid damage to it. However, the internal processing of the network connector The complex circuit layout of the transformer A1 is required in the circuit, and the area of the circuit board used for the processing circuit is relatively large, and the overall man-hour and cost are difficult to effectively reduce, and the network connector is considered to comply with Power over Ethernet (Power over Ethernet, Referred to as PoE power supply, through the twisted pair to transmit power and data) technical specifications, then in the transformer A1, the resistor A2 and the first capacitor A3 are connected in series to achieve the function of eliminating interference signals, but the transformer A1 connects the resistor A2 and the first capacitor A3 Capacitor A3 is not a necessary circuit design. Even if the resistor A2 and the first capacitor A3 are not set, the application function of the transformer A1 will not be affected. Capacitor A3 forms unnecessary waste for transformer A1, but cannot substantially enhance or improve the efficiency of transformer A1 in application.

In addition, in order to solve the problem of noise interference during signal transmission in the above-mentioned network signal processing circuit, the applicant in this case used the existing electronic components and circuit design to carry out research and development and improvement, and provided a signal processing circuit on the circuit board, as shown in the figure As shown in 5, a plurality of circuit channels B3 are connected between the first connection terminal B1 and the second connection terminal B2 of the processing circuit B, and a coupling capacitor B4 and an autotransformer B5 are respectively connected to each circuit channel B3 Then connect to the ground terminal B51, and a common mode inductance unit C is connected in parallel between any two adjacent circuit channels B3, when the network signal is transmitted to the circuit channel B3 through the first connection terminal B1, it can pass through each common mode The mode inductance unit C performs low-pass filtering (Low Pass) or eliminates the electromagnetic wave interference generated by the common mode current, and isolates the electrical appliances and coupling signals through each coupling capacitor B4, and after the autotransformer B5 filters out the noise in the network signal, It is then transmitted to the ground terminal B51 for exclusion, so that the electromagnetic wave or noise interference in the network signal can be filtered out, so as to achieve the purpose of stably transmitting the network signal. However, the circuit board that meets the PoE power supply specification on the market Both are provided with a resistor A2 and a first capacitor A3, the circuit design of the processing circuit B cannot be applied to the existing circuit board, and it is necessary to produce suitable circuit boards for the processing circuit B, or need to cooperate with the circuit board Electronic components change the circuit layout, increase the complexity of the circuit layout, and use more electronic components to occupy more circuit board area, and the man-hours and costs required for the overall production are also relatively increased. Industry players are eager to study the direction of improvement.

Utility model content

In view of the problems and deficiencies in the above-mentioned prior art, the inventor of this case designed this kind of network signal by collecting relevant data, evaluating and considering it in many ways, and using years of experience in research and development in this industry for continuous trial production and modification. noise filtering circuit.

The main purpose of the utility model is that a circuit channel is connected between the first connection end and the second connection end of the processing circuit, and a common-mode inductance unit is connected in parallel between any two adjacent circuit channels, and each circuit channel On one side adjacent to the common mode inductance unit, there are coupling capacitors connected in series and autotransformers connected in parallel between any two adjacent circuit channels, so that the electromagnetic wave or noise mixed in the network signal transmitted by the circuit channel can be filtered. In addition, this kind of processing circuit can be connected and extended by the autotransformer to connect and extend the first connection and the second connection, and respectively connect the resistor on the circuit board and the first capacitor and the second capacitor in series for grounding circuit design, so as to be applied to the existing Circuit boards that meet PoE power supply specifications do not need to change the circuit layout in conjunction with the electronic components set on the circuit board, and achieve the purpose of reducing production costs, which is more practical and applicable.

The secondary purpose of the present invention is that the first connection end and the second connection end of the processing circuit are respectively electrically connected to the network connector and the network chip, when the network connector is disturbed by electromagnetic waves or noise during the transmission of network signals, The noise in each circuit channel can be filtered through the common-mode inductance unit, and then passed through the coupling capacitor and autotransformer, and then transmitted to the ground terminal through the resistor, first capacitor and second capacitor on the circuit board for elimination , so that the network signal can be stably transmitted to the network chip for processing, so as to avoid instability or interruption in the process of signal transmission, and ensure a more stable quality of network signal transmission.

In order to achieve the above object, the utility model provides a network signal noise filtering circuit, including a processing circuit arranged on a circuit board, the processing circuit has a first connection end electrically connected to a preset network connector and an electrical Connected to the second connection end of the preset network chip, and at least one circuit channel is connected between the first connection end and the second connection end, and any two adjacent circuit channels are connected in parallel with a common-mode inductance unit, Then, on each circuit channel, a coupling capacitor is connected in series adjacent to one side of the common-mode inductance unit, and an autotransformer is connected in parallel between any two adjacent circuit channels, and the first connection extended by the autotransformer is connected in series There is a resistor and a first capacitor on the circuit board, and the second connection is connected in series with the second capacitor on the circuit board.

In one embodiment of the present invention, the circuit board is provided with a resistor, a first capacitor and a second capacitor, and the first connection of the autotransformer connects the resistor and the first capacitor in series to the ground terminal for grounding. And the second wire is connected in series with the second capacitor and then connected to the ground terminal for grounding.

Description of drawings

Fig. 1 is the simple and easy circuit diagram of the present utility model;

Fig. 2 is a block diagram of the utility model;

Fig. 3 is the block diagram of preferred embodiment of the present utility model;

Fig. 4 is a simple circuit diagram of an existing lightning protection module;

FIG. 5 is a simplified circuit diagram of an existing network signal processing circuit.

Description of reference signs: 1-processing circuit; 10-circuit board; 10a-ground terminal; 10b-ground terminal; 101-resistance; 102-first capacitor; 103-second capacitor; 11-first connection terminal; 13-circuit channel; 14-coupling capacitor; 15-autotransformer; 151-first wiring; 152-second wiring; 2-common mode inductance unit; 3-network chip; 4-network connector ;A-lightning protection module; A1-transformer; A11-primary side coil; A111-middle tap; A12-secondary side coil; A121-middle tap; A2-resistor; A3-first capacitor; A31-grounding terminal; A4-second capacitor; A41-ground terminal; B-processing circuit; B1-first connection terminal; B2-second connection terminal; B3-circuit channel; B4-coupling capacitor; B5-autotransformer; B51-ground terminal ; C-common mode inductance unit.

Detailed ways

In order to achieve the above-mentioned purpose and effect, the technical means and the structure adopted by the utility model are hereby illustrated in detail with respect to the preferred embodiment of the utility model and its structure and function are as follows.

Shown in Fig. 1, Fig. 2, Fig. 3 are respectively simple circuit diagram, block diagram and the block diagram of preferred embodiment of the present utility model, can clearly find out from the figure, the network signal noise filter circuit that the utility model provides It includes a processing circuit 1 arranged on a circuit board 10, and preset electronic components and circuit layouts such as a resistor 101, a first capacitor 102, and a second capacitor 103 are arranged on the circuit board 10, and the processing circuit 1 has a first The connection end 11, the second connection end 12, and at least one circuit channel 13 connected between the first connection end 11 and the second connection end 12, and a common mode inductance unit is connected in parallel between any two adjacent circuit channels 13 2. Each circuit channel 13 is connected in series with a coupling capacitor 14 on one side adjacent to the common mode inductance unit 2, and then an autotransformer 15 is connected in parallel between any two adjacent circuit channels 13, and the autotransformer The iron core of 15 is wound with a first coil winding and a second coil winding (not shown in the figure), and the first coil winding or the second coil winding is connected and extended with a first wire 151 and a second wire 152, and The resistor 101 and the first capacitor 102 on the circuit board 10 are connected in series by the first connection 151 and then connected to the ground terminal 10a for grounding, and the second connection 152 is connected in series to the second capacitor 103 on the circuit board 10 and then connected to The ground terminal 10b is grounded to form the network signal noise filtering circuit of the present invention.

In addition, the first connection ends 11 of the processing circuit 1 are respectively electrically connected to the terminal groups of the network connector 4, and the second connection ends 12 are respectively electrically connected to the pin groups of the network chip 3, and the network chip 3 and the processing The circuit 1 is preferably implemented as being arranged on the circuit board 10 and connected to the external network connector 4 by the circuit board 10, but in actual application, the network connector 4 and the processing circuit 1 can also be arranged on the circuit board 10 , or the circuit board 10 can be further arranged inside the network connector 4, and then the circuit board 10 is connected to the network chip 3 on the external circuit board; in addition, the circuit board 10 can be further provided with a power supply (such as a dry battery, a charging battery, lithium battery or button battery, etc., or can be connected to an external mains power supply through a power cord, etc.), and the circuit board 10 provides the required processing circuit 1, network chip 3 and network connector 4, etc. The power supply, how the network chip 3 and the network connector 4 are connected and configured in this part are prior art, and the detailed composition is not the main point of this case, so it will not be repeated.

However, there are eight pins on the first connecting terminal 11 at one side of the above-mentioned processing circuit 1, which are respectively MX0+, MX0-, MX1+, MX1-, MX2+, MX2-, MX3+ and MX3-, and are connected to the processing circuit 1. There are eight pins on the first connection end 11 at the other side, and each pin is respectively MD0+, MD0-, MD1+, MD1-, MD2+, MD2-, MD3+ and MD3-, which are only used to distinguish the pins Each number can still be changed according to the actual design requirements.

When the processing circuit 1 in the utility model is used in practice, if the terminal group of the network connector 4 receives an instantaneous high voltage or surge generated by an external lightning strike during the process of transmitting network signals, it can be transmitted to the processing circuit through the network connector 4 Each circuit channel 13 in 1, and through the coupling effect of each coupling transformer 15, the instantaneous high voltage, surge, etc. are reduced, and then the resistor 101 and the first capacitor 102 connected in series through the first connection 151 are transmitted to the ground terminal 10a for elimination , but because the second connection 152 of the autotransformer 15 is connected in series with the second capacitor 103 for grounding, although this processing circuit 1 does not have the function of lightning protection, the processing circuit 1 can be connected to the extended first capacitor through the autotransformer 15. The wiring 151 and the second wiring 152 are respectively connected in series with the resistor 101 on the circuit board 10, the first capacitor 102 and the second capacitor 103 are connected to the ground terminals 10a, 10b. The circuit design is applied to existing circuit boards that meet PoE power supply specifications. 10, and the processing circuit 1 does not need to change the circuit layout in conjunction with the electronic components arranged on the circuit board 10, so as to achieve the purpose of reducing production costs, which is more practical and applicable.

The above-mentioned processing circuit 1 is located on each circuit channel 13 and the capacitance value of the coupling capacitor 14 connected in series can be between 0.03μF～1.0μFμF, and the capacitance value of a better implementation can be 0.1μF, and the processing circuit 1 is located at any two The inductance value of the autotransformers 15 connected in parallel between adjacent circuit channels 13 can be between 30 μH to 350 μH, and the direct current resistance (DCR) can be between 0.5 and 2 ohms. The optimal implementation of the inductance value is 80 μH, The DC resistance (DCR) is 1 ohm.

When the network connector 4 receives interference such as external electromagnetic waves (EMI) or noise (Noise) in the process of transmitting network signals, in order to improve the capacitance or inductance value of the above-mentioned coupling capacitors 14 and autotransformer 15 due to too large or too large If the noise mixed in the network signal is not easy to filter out, it can be filtered through each common mode inductance unit 2, and the noise in each circuit channel 13 is passed through each coupling capacitor 14 and autotransformer 15, and then passed through The resistor 101 on the circuit board 10, the first capacitor 102, the ground terminal 10a, 10b of the second capacitor 103 are excluded, to filter out the noise interference in each circuit channel 13, and can meet the requirements of the detection specification (IEEE regulation), The network signal can be stably transmitted to the network chip 3 through the circuit channel 13 for processing, so as to avoid instability or interruption during the signal transmission process, thereby making the quality of network signal transmission more stable.

Furthermore, the inductance value of the common mode inductance unit 2 can be between 90 ohms and 1000 ohms, and according to the transmission of network signals by each circuit channel 13 in the processing circuit 1, the noise mixed in the signals of various frequency bands is different. , the inductance value of the common mode inductance unit 2 can preferably be 800 ohms, and in the process of signal transmission of each circuit channel 13, if other signals enter to generate interference such as electromagnetic waves or noise, the common mode inductance can pass through the common mode inductance unit 2. Unit 2 uses an inductance value of about 800 ohms to filter out the noise contained in the network signal, but in actual application, the inductance value can also be adjusted according to the actual application or circuit design to improve the stability of high-frequency network signal transmission .

To sum up, the processing circuit 1 in the present invention is arranged on the circuit board 10, and a circuit channel 13 is connected between the first connection end 11 and the second connection end 12, and any two adjacent circuit channels 13 A common-mode inductance unit 2 is connected in parallel between each circuit channel 13, and a coupling capacitor 14 is connected in series on each circuit channel 13, and an autotransformer 15 is connected in parallel between any two adjacent circuit channels 13, and the autotransformer 15 is connected to an extended The first connection 151 and the second connection 152 are respectively connected in series with the resistor 101 on the circuit board 10 and the first capacitor 102 and the second capacitor 103 to be grounded as the key point of protection. The circuit design of the autotransformer 15 in this processing circuit 1 It can be applied to the existing circuit board 10 conforming to the PoE power supply specification, and there is no need to change the circuit layout of the electronic components on the circuit board 10, so as to achieve the purpose of reducing the production cost, and is more practical and applicable.

The above detailed description is just a description of a preferred feasible embodiment of the present utility model, but this embodiment is not used to limit the protection scope of the present utility model, and all other works completed without departing from the technical spirit disclosed in the present utility model Equal changes and modified changes should be included in the protection scope of the present utility model.

Claims (2)

1. A network signal noise filtering circuit, characterized in that it includes a processing circuit arranged on a circuit board, the processing circuit has a first connection end electrically connected to a preset network connector and electrically connected to a preset The second connection end of the network chip, and at least one circuit channel is connected between the first connection end and the second connection end, and a common mode inductance unit is connected in parallel between any two adjacent circuit channels, and each circuit There are coupling capacitors connected in series on the channel adjacent to the side of the common mode inductance unit, and an autotransformer is connected in parallel between any two adjacent circuit channels, and the first wiring extended by the autotransformer is connected in series with a The resistance and the first capacitor are connected in series, and the second capacitor on the circuit board is connected in series. 2. The network signal noise filtering circuit according to claim 1, characterized in that, the circuit board is provided with a resistor, a first capacitor and a second capacitor, and the first connection of the autotransformer is connected in series with the resistor and the first capacitor. The capacitor is then connected to the ground terminal for grounding, and the second wire is connected in series with the second capacitor and then connected to the ground terminal for grounding.