CN201115282Y - A digital processing circuit board structure to prevent propagation of common-mode interference - Google Patents

Abstract

The utility model provides a digital processing circuit board structure for avoiding transmission of common mode interference; an isolated zone is arranged on the periphery of the signal lines of an interference source on the digital processing circuit board and the interference source is distributed in the isolated zone; the other leads of the circuit board are distributed outside the isolated zone. The technical proposal provided by the utility model can not only easily solve the interference problems, but also reduce the workload of the developers and greatly shorten the development cycle of the products.

Description

A digital processing circuit board structure to prevent propagation of common-mode interference

technical field

The utility model relates to electromagnetic compatibility technology, specifically, a digital processing circuit board in a TV set to prevent common-mode interference from propagating.

Background technique

Today, with the digitization of information, digital processing technology and corresponding integrated circuits are widely used in various electronic devices, such as computers, televisions, mobile phones and so on. The printed circuit boards of these devices are generally equipped with more than one integrated circuit. They are either digital ICs, or digital ICs and analog ICs. The operating frequencies of these circuits are high or low, and the high High-frequency signals, especially digital high-frequency signals, often cause interference to other circuits through various channels, making them unable to work normally. For example, the digital processing board of a TV set has more than one digital IC on it. Since the transmission of data signals between integrated circuits generally forms a loop through the ground wire, for high-frequency signals, the wire is equivalent to a For distributed parameter circuits, there is a potential difference at both ends of the circuit. For example, as long as there is signal transmission between any two ICs and the signal transmission is returned by the ground wire, there will inevitably be a difference between the ground points of the two ICs. There will be a potential difference, such as between A and B in Figure 1. Since this potential difference is a high-frequency potential difference, it can transmit signals to the space through the ground layer (the ground layer in the multilayer board) or other leads in the circuit, interfering with the normal operation of other electrical equipment, as shown in Figure 1 Indicated by the thick black line. In this case, in order to ensure that the equipment can work normally, countries or international organizations have formulated corresponding standards to limit the interference signals. Therefore, equipment manufacturers must take suppression measures against the interference signals to make the EMC ( Electromagnetic Compatibility) meet the standard.

There are various suppression measures. The traditional solution is to add common mode inductance to each lead (for example, put a ring magnetic bead on the lead), or ground the PCB and each lead as much as possible, or install a shielding box to attenuate the interference signal launch, but this not only increases the cost of materials, but also unsatisfactory in some cases.

Utility model content

The purpose of the utility model is to provide a digital processing circuit board structure to prevent the propagation of common-mode interference, aiming at solving the problem of common-mode interference propagation of the digital processing circuit board existing in the prior art.

The utility model is realized in this way, a digital processing circuit board prevents the structure of common mode interference from propagating, an isolation zone is arranged on the periphery of the signal line of the interference voltage source on the digital processing circuit board, and the distribution of the interference voltage source Within the isolation zone, other leads of the circuit board are distributed outside the isolation zone.

The signal line of the interference voltage source includes a power ground line as a signal return flow.

The isolation band is arranged tightly around the signal line of the interference source.

The isolation zone can be a conductor or an insulator.

The other leads include printed wires and non-printed wires.

The width of the isolation zone is more than 1 mm.

The utility model overcomes the deficiencies of the prior art and adopts the technical scheme of setting an isolation zone around the signal line forming the interference source, which not only can solve the interference problem simply, reliably and easily, but also has the greater advantage that it can reduce the workload of developers and greatly To shorten the product development cycle.

Description of drawings

FIG. 1 is a schematic diagram of a high-frequency digital signal line in the prior art;

Fig. 2 is a schematic diagram of an embodiment of the utility model.

Detailed ways

In order to make the purpose, technical solution and advantages of the utility model clearer, the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

In Fig. 1, 1 is a printed circuit board, 2 is an isolation strip arranged on a printed circuit board according to the technical scheme of the present application, 3 is an integrated circuit, 4 is a lead wire between circuits, and 5 is a wire on a printed circuit board. other circuits.

Assuming that there is high-frequency digital signal transmission between the two integrated circuits on the board, the circuit is generally composed of two upper and lower connections (thick black lines in Figure 1) distributed on the mirror layer of the PCB. For high-frequency digital signals, a wire is equivalent to a distributed parameter circuit, and there will be a potential difference at both ends of it, as shown in Figure 2. There is a potential difference between A and B. Due to the potential difference High-frequency characteristics, it can interfere with the normal operation of other devices by transmitting signals to the space through the ground layer (the ground layer in the multi-layer board) or by coupling to other leads in the circuit. In order to avoid this situation, the technical solution provided by the utility model has adopted the following measures:

Set a nearly closed isolation zone along the periphery of the high-frequency digital signal line on the circuit board, and use this isolation zone to isolate the interference source from other leads. There are no or few other signal lines other than the frequency digital signal lines.

The signal line of the interference source includes a power supply ground line or a Vcc lead line as a signal return flow.

The isolation zone should be tightly set around the signal line of the interference source.

The isolation zone can be a conductor or an insulator, and its width is more than 0.5 mm.

The other leads include printed wires and non-printed wires.

By adopting the technical solution provided by the utility model, both the basic model and its derived models can easily pass the EMC test, thereby greatly reducing the workload of developers and shortening the product development cycle.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present utility model shall be included in this utility model. within the scope of protection of utility models.

Claims (6)

1. A digital processing circuit board prevents the structure of common-mode interference from propagating, characterized in that an isolation zone is arranged on the periphery of the signal line of the interference source on the digital processing circuit board, and the interference source is distributed in the Inside the isolation zone, other leads of the circuit board are distributed outside the isolation zone. 2. The structure according to claim 1, wherein the signal line of the interference source includes a power line/ground line as a signal return flow. 3. The structure according to claim 1, characterized in that, said isolation zone is arranged tightly around said signal line of said interference source. 4. The structure according to claim 1, characterized in that the isolation zone can be a conductor or an insulator. 5. The structure according to claim 1, wherein said leads include printed wires and non-printed wires. 6. The structure according to claim 1, characterized in that the width of the isolation strip is more than 0.5 mm.

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