JP2005109261A - Printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed wiring board, wherein the value of impedance can easily be revised, the impedance can be provided to ground wiring itself, without the need for a wide mount area, and also interference of radiated noise components with an electrical signal or the like delivered through adjacent signal wires can be suppressed. <P>SOLUTION: The earth wire 6 is provided with a resistive element 7, a capacitive element 8, and a coil element 9, the impedance of which is a prescribed value which is being zero. Further, the both ends of the ground wire 6 are respectively provided with ground vias 10, 11. The noise component is superimposed from the signal wires 4 to the ground wire 6, through which the noise component A are delivered. The resistive element 7 can reduce the amplitude of the noise component A. Moreover, the capacitive element 8 and the coil element 9 adjust the phases of the noise components A, B in a way of being overlapped with each other, thereby canceling the respective amplitudes with each other and decreasing the amount of noise. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a printed wiring board on which electronic components are mounted, and more particularly to a printed wiring board in which measures are taken to suppress interference to adjacent signal wiring, peripheral circuits, and peripheral electronic equipment due to noise radiation.

Conventionally, printed circuit boards on which electronic components are mounted have electrical components that transmit the peripheral circuits and peripheral electronic devices, particularly adjacent signal wiring, by noise components radiated from the wiring that connects the electronic components and transmits electrical signals. There has been a problem of causing interference to the signal, and therefore, the performance deterioration of the entire electronic equipment using this printed wiring board has been caused.

In order to prevent problems such as performance degradation, a design method is used in which ground wiring is arranged / wired so as to surround the wiring that radiates noise components. However, it is difficult to completely surround a wiring that radiates a noise component with a ground wiring in a board of an electronic device in which the wiring is complicated. Also, inadequate ground wiring can sometimes promote radiation of noise components.

Also, by providing resistance elements and capacitor elements in the wiring that radiates noise components and adjacent signal wiring, radiation of noise components can be suppressed, but if this element value is not appropriate, electronic components mounted on the board There is a case in which an electric signal transmitted between the terminals is not accurately transmitted and a circuit does not operate normally.

On the other hand, the ground wiring provided to suppress the radiated noise component is radiated from the electrical signal transmitted in the adjacent wiring, unlike the wiring that is paired with the signal wiring to transmit the signal. Therefore, even if a device for suppressing the noise component radiated to the ground wiring itself is applied, the circuit performance is not adversely affected.

Therefore, it is ideal if the radiated noise component can be effectively suppressed by devising the ground wiring arranged / wired adjacent to the wiring that radiates the noise component.

As an example of this, the noise was radiated by forming an impedance in a grid pattern on the ground wiring to suppress interference with the electrical signal transmitted through the adjacent signal wiring. There are some (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-17304 (page 2-3, FIG. 1)

However, in the printed wiring board described in Patent Document 1, since the grid pattern is printed on the ground wiring, it is difficult to flexibly adjust the impedance value once set. Further, since a larger mounting area is required to form a grid pattern, it is not suitable for a printed wiring board of an electronic device that is to be miniaturized.

Therefore, according to the present invention, the impedance value can be easily changed, and the impedance can be provided in the ground wiring itself without requiring a large mounting area, and at the same time, the radiated noise component is transmitted through the adjacent signal wiring. An object of the present invention is to provide a printed wiring board capable of suppressing interference with signals and the like.

In order to achieve the above object, a printed wiring board according to the present invention includes a substrate, a signal wiring disposed on the substrate, a ground wiring disposed on the substrate adjacent to the signal wiring,
The ground wiring disposed at both end portions of the ground wiring, which reversely reflects the noise component superimposed on the ground wiring, and disposed on the substrate so as to be connected to the ground wiring, is generated from the signal wiring and the ground wiring And a resistance element that consumes a noise component superimposed on the.

According to the printed wiring board of the present invention, the impedance value can be easily changed, and the impedance can be provided in the ground wiring itself without requiring a large mounting area.
It is possible to suppress the radiated noise component from interfering with an electric signal transmitted through the adjacent signal wiring.

  An embodiment of an electronic circuit board according to the present invention will be described below with reference to FIG.

FIG. 1 shows a printed wiring board to which the present invention is applied. In this embodiment,
A case where two electronic components are mounted on a substrate as shown in FIG. 1 and these are electrically connected will be described as an example.

  In the printed wiring board shown in FIG. 1, an electronic component 2 and an electronic component 3 are mounted on a substrate 1.

In order to transmit an electric signal in both directions or a single direction between the electronic component 2 and the electronic component 3,
The signal wiring 4 and the signal wiring 5 are printed on the substrate 1. When a noise component is radiated from the electric signal transmitted through the signal wiring 4, the radiated noise component interferes with the electric signal transmitted through the signal wiring 5. The radiated noise component further generates noise radiation using the signal wiring 5 as a secondary noise source. Due to these phenomena, the radiated noise component also affects the electronic component 2, the electronic component 3, and other wirings and electrical circuits.

In order to suppress these radiated noise components, the ground wiring 6 is arranged / wired on the substrate 1 so as to be adjacent to the signal wiring 4. The ground wiring 6 is provided with a resistance element 7, a capacitor element 8 and a coil element 9 having a predetermined impedance value which is not zero. Further, ground vias 10 and 11 are provided at both end portions of the ground wiring 6, respectively.

In the above configuration, the ground wiring 6 is electromagnetically coupled to the signal wiring 4 in the noise radiation band,
Due to this electromagnetic coupling, a noise component is superimposed from the signal wiring 4 to the ground wiring 6,
Noise component A is transmitted through the ground wiring 6. This noise component A is reflected in reverse phase at the ground vias 10 and 11, and is transmitted through the ground wiring 6 in the opposite direction to the noise component A (this reverse-phase reflected component is referred to as noise component B). The resistance element 7 can reduce the amplitude of the noise component A and the noise component B. Further, the capacitor element 8 and the coil element 9 can change the transmission characteristics of the noise component A and the noise component B on the ground wiring. Specifically, by adjusting and superimposing the phases of the noise component A and the noise component B, it is possible to reduce the amount of noise that exists as a standing wave on the ground wiring 6 by acting so as to cancel each other's amplitude. . As described above, the effect of suppressing the noise component radiated from the signal wiring 4 can be obtained.

Therefore, according to the present embodiment, the noise component radiated from the signal wiring 4 is the resistance element 7,
Since it is suppressed by the capacitor element 8 and the coil element 9, it is possible to obtain an effect of suppressing interference with an electric signal transmitted through the signal wiring 5.

In addition, since the ground wiring 6 is provided with a resistance element 7, a capacitor element 8, and a coil element 9 instead of a printed wiring, it does not require a large mounting area, which is suitable for downsizing of electronic equipment. Therefore, the effect that the impedance value can be easily adjusted can be obtained.

FIG. 2 is a mounting diagram of a printed wiring board which is a modification of the above embodiment. In this modification, the resistor element 7, the capacitor element 8, and the coil element 9 connected in series in the above-described embodiment are converted and connected in parallel.

  Also in this modified example, the same effect as the above-described embodiment can be obtained.

Here, in the present embodiment, a configuration in which three types of the resistor element 5, the capacitor element 6 and the coil element 7 (hereinafter referred to as each element) are combined is taken as an example, but each element is used alone. May also be used in two types of combinations, and it does not matter if they are arranged in parallel or connected in series. Furthermore, each element may be used singly or in plural. Further, although two ground vias 10 and 11 are used for the ground wiring 6, the earth vias may be used singly or plurally, and it is questionable that the arrangement location is in the middle before and after each element. Absent.

Moreover, the board | substrate 1 consists of a phenol resin, a glass epoxy resin, etc., and includes all the board | substrates used for an electronic device etc. Moreover, if it is a 2 layer board | substrate, it does not ask | require that it is a multilayer board | substrate.

Further, in this embodiment, the signal wiring 4 and the like are printed on the surface of the substrate 1, but when the substrate 1 is a multilayer substrate, it may be printed on the inner layer portion thereof.

The mounting diagram of the embodiment of the printed wiring board to which the present invention is applied. The mounting diagram of the modification of embodiment of the printed wiring board to which this invention is applied.

Explanation of symbols

1 substrate, 2 electronic components, 3 electronic components, 4 signal wiring, 5 signal wiring, 6 ground wiring, 7 resistance element, 8 capacitor element, 9 coil element, 10 ground via, 11 ground via, A noise component, B noise component

Claims (3)

A substrate,
Signal wiring disposed on the substrate;
A ground wiring disposed on the substrate adjacent to the signal wiring; and
A ground that is disposed at both end portions of the ground wiring and reversely reflects a noise component superimposed on the ground wiring;
A printed wiring board comprising: a resistance element that is disposed on the substrate so as to be connected to the ground wiring, and that consumes a noise component generated from the signal wiring and superimposed on the ground wiring. A substrate,
Signal wiring disposed on the substrate;
A ground wiring disposed on the substrate adjacent to the signal wiring; and
A ground that is disposed at both end portions of the ground wiring and reversely reflects a noise component superimposed on the ground wiring;
A coil element that is disposed on the substrate so as to be connected to the ground wiring, and that changes a transmission characteristic of the noise component generated from the signal wiring and superimposed on the ground wiring on the ground wiring. Printed wiring board. A substrate,
Signal wiring disposed on the substrate;
A ground wiring disposed on the substrate adjacent to the signal wiring; and
A ground that is disposed at both end portions of the ground wiring and reversely reflects a noise component superimposed on the ground wiring;
A capacitor element that is arranged on the substrate so as to be connected to the ground wiring, and that changes a transmission characteristic of the noise component generated from the signal wiring and superimposed on the ground wiring on the ground wiring. Printed wiring board.

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