JP2001326432A - Connection structure of printed wiring board and cable, and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the connection structure of a printed wiring board and a cable and electronic equipment that can inhibit radiation noise caused by a standing wave phenomenon occurring at the cable by connecting a specific impedance element at a place where the printed wiring board is connected to the cable. SOLUTION: On a printed wiring board 1, a packaging land or the like is provided in advance in cable wiring 3a, a wiring pattern 4a corresponding to cable wiring 3b, and a wiring pattern 4b. An impedance element 6 such as the cable wiring 3a and resistance element having an impedance value that is equal to the characteristic impedance of the cable wiring 3b is connected to the packaging land by such method as soldering.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure between a printed wiring board and a cable and an electronic device, and more particularly to a connection structure between a printed wiring board and a cable in an electronic device having the printed wiring board and a cable. The present invention relates to a connection structure between a printed wiring board and a cable suitable for suppressing radiation noise from an electronic device and an electronic device.

[0002]

2. Description of the Related Art Conventionally, when an electric signal is transmitted by a cable between two printed wiring boards mounted on an electronic device, for example, a high frequency current which is a high frequency component of a digital clock signal of the printed wiring board is wired. And radiate it as a large unnecessary electromagnetic wave. The reason for this is that if the wiring configuration of the cable is thin or the cable length is long, it acts as an antenna that easily emits electromagnetic waves.

As a conventional method for preventing unnecessary electromagnetic waves from this cable, a cable having a ferrite core or a shield structure is often used. In the former, a high-frequency current is suppressed by performing a process such as winding a cable around a ferrite core containing a magnetic material, by the inductance and resistance of the ferrite core. In the latter case, a metal foil or the like is separately wound around each signal wiring of a cable, so that the electromagnetic wave is suppressed by the effect of shielding the electromagnetic wave by the metal. However,
The above method increases the manufacturing cost and also requires more wiring space when mounting the cable on the electronic device.

As shown in FIG. 7, when there is a digital signal wiring pattern 4d and a ground wiring pattern 4e for transmitting digital logic signals from an IC 12 mounted on the printed wiring board 1, the digital signal wiring There is a method of inserting a resistance element 6a or the like near the IC output pin of the pattern 4d to suppress a signal current flowing through the wiring. In the figure, 2 is a housing metal part, 3d is digital signal wiring of a cable, 3e is ground wiring of a cable, 5
Indicates a connector.

On the other hand, as a technique for suppressing radiation noise generated from a radiation electromagnetic wave of a high-frequency current, for example, Japanese Patent Laid-Open No. 7-2
No. 25634 has been proposed. The publication discloses a ground layer provided on a substrate on which a plurality of electronic components are mounted,
In an information processing apparatus for electrically connecting a conductive body frame having a low impedance to the ground layer at first and second at least two or more connection points, the connection point includes the ground layer and the An information processing device is disclosed, which is a connection point formed between a main frame and a main frame via a resistance member.

[0006]

However, in the above conventional example, the wiring provided on the cable is used for a plurality of purposes, for example, for an analog signal, a digital signal, a power supply, and a ground. Inserting a resistance element or the like into the power supply or ground wiring
Since the power supply potential and the ground potential are changed, it is not preferable in terms of circuit operation.

[0007] When wirings for a plurality of uses are mixed as described above, high-frequency currents such as harmonic components of digital signals flowing through a printed wiring board or a cable flow into wirings for other uses, or wirings for other purposes are used. You may be guided between.

When such a high-frequency current flows on the cable wiring, the printed wiring board and the cable have different impedances, and are transmitted while causing reflection. By repeating this reflection, a standing wave phenomenon occurs at a certain frequency. At the frequency of the standing wave, a strong electromagnetic wave is generated, which easily causes a problem of radiation noise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a standing wave generated in a cable portion is formed by connecting a predetermined impedance element between wirings at a connection point between a printed wiring board and a cable. It is an object of the present invention to provide a connection structure between a printed wiring board and a cable and an electronic device capable of suppressing radiation noise caused by a phenomenon.

[0010]

In order to achieve the above object, according to the present invention, at least two printed wiring boards and a plurality of wirings for transmitting electric signals between the two printed wiring boards are provided. A connection structure between a printed wiring board and a cable, which is applied to an electronic device in which a provided cable is mounted inside a housing, and connects between two wires via an impedance element corresponding to a characteristic impedance between two adjacent cable wires. It is characterized by being connected.

In order to achieve the above object, a second aspect of the present invention is characterized in that the impedance element has a resistance.

In order to achieve the above object, the invention according to claim 3 is characterized in that the impedance element has resistance and capacitance.

In order to achieve the above object, the invention according to claim 4 is characterized in that the impedance element has resistance, capacitance, and inductance.

According to a fifth aspect of the present invention, the printed wiring board includes a digital logic circuit, and the two wirings are a digital logic signal wiring and a ground wiring. .

In order to achieve the above object, the invention according to claim 6 is characterized in that the two wirings are a power supply wiring and a ground wiring, and the impedance element has resistance and capacitance. .

In order to achieve the above object, the invention according to claim 7 is characterized in that the inductance is formed by a wiring pattern having a folded shape.

In order to achieve the above object, the invention according to claim 8 is characterized in that the inductance is formed by a spiral wiring pattern.

In order to achieve the above object, the invention according to claim 9 is characterized in that the capacitance is constituted by a comb-shaped wiring pattern.

In order to achieve the above object, a tenth aspect of the present invention is characterized in that the connection structure is provided between a plurality of wirings.

In order to achieve the above object, according to the present invention, a cable having at least two printed wiring boards and a plurality of wirings for transmitting an electric signal between the two printed wiring boards is provided inside a housing. Wherein the two wirings are connected via an impedance element corresponding to a characteristic impedance between two adjacent cable wirings.

In order to achieve the above object, a twelfth aspect of the present invention is characterized in that the impedance element has a resistance.

In order to achieve the above object, the invention according to claim 13 is characterized in that the impedance element has resistance and capacitance.

In order to achieve the above object, the invention according to claim 14 is characterized in that the impedance element has resistance, capacitance and inductance.

In order to achieve the above object, the invention according to claim 15 is characterized in that the printed wiring board includes a digital logic circuit, and the two wirings are a digital logic signal wiring and a ground wiring. .

In order to achieve the above object, the invention according to claim 16 is characterized in that the two wirings are a power supply wiring and a ground wiring, and the impedance element has resistance and capacitance. .

In order to achieve the above object, the invention according to claim 17 is characterized in that the inductance is formed by a wiring pattern having a folded shape.

In order to achieve the above object, the invention according to claim 18 is characterized in that the inductance is formed by a spiral wiring pattern.

In order to achieve the above object, the invention according to claim 19 is characterized in that the capacitance is constituted by a comb-shaped wiring pattern.

In order to achieve the above object, the invention according to claim 20 is characterized in that the connection structure is provided between a plurality of wirings.

[0030]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[First Embodiment] FIG. 1 shows a first embodiment of the present invention.
FIG. 9 is a perspective view showing an enlarged configuration of a connection portion between a printed wiring board and a cable in the electronic device according to the embodiment. More specifically, a printed wiring board 1 is provided inside a housing of an electronic device, and a cable for transmitting an electric signal from the printed wiring board 1 to another printed wiring board (not shown). The wiring 3a and the cable wiring 3b are provided. In the figure, reference numeral 2 denotes a housing metal part. Printed wiring board 1
A wiring pattern 4a and a wiring pattern 4b respectively corresponding to the cable wiring 3a and the cable wiring 3b are provided thereon, and a connector 5 and an impedance element 6 are mounted thereon. Each cable wiring 3a, 3b and wiring patterns 4a, 4b are electrically connected via a connector 5.

Further, mounting lands (not shown) and the like are provided in advance on the wiring patterns 4a and 4b, and an impedance element 6 such as a resistance element is connected to the mounting lands by a method such as soldering. Here, the impedance element 6 has an impedance value equivalent to the characteristic impedance of the cable wirings 3a and 3b. Further, the impedance element 6 may be formed of an element having a characteristic that changes with respect to the frequency, such as an inductance element. Further, it is more desirable that the connection between the cable wirings 3a, 3b and the wiring patterns 4a, 4b is made near the connector, and the connector itself may not be provided.

As described above, according to the first embodiment of the present invention, at the connection point between the printed wiring board 1 and the cable, the mounting land on which the impedance element 6 can be arranged in advance between the wirings is formed. By providing an impedance element 6 corresponding to the characteristic impedance of the cable, a standing wave at the cable portion is suppressed. This is because the frequency at which a standing wave occurs depends on the length of the cable, the characteristic impedance, and the like. The characteristic impedance is determined by the dielectric and wiring shape that make up the wiring, the physical positional relationship between the two wirings, and the metal of the housing. It can be determined by the positional relationship with the parts.

Accordingly, by connecting a predetermined impedance element 6 between the wirings at the connection point between the printed wiring board 1 and the cable, it is possible to suppress radiation noise caused by the standing wave phenomenon occurring in the cable portion. An effect that is effective for

[Second Embodiment] FIG. 2 shows a second embodiment of the present invention.
FIG. 9 is a top view showing a configuration in which a connection portion between a printed wiring board and a cable in the electronic device according to the embodiment of the present invention is enlarged. More specifically, a printed wiring board 1 is provided inside a housing of an electronic device, and a cable for transmitting an electric signal from the printed wiring board 1 to another printed wiring board (not shown). The wiring 3a and the cable wiring 3b are provided. On the printed wiring board 1, the cable wiring 3
a, wiring patterns 4 respectively corresponding to the cable wiring 3b
a, a wiring pattern 4b is provided, and a connector 5, an impedance element 6, and an impedance element 6 'are mounted. Each cable wiring 3a, 3b and wiring patterns 4a, 4b are electrically connected via a connector 5.

Further, mounting lands 7 and 7 'are provided in advance between the wiring patterns 4a and 4b, and the impedance elements 6 and the impedance elements 6' having frequency characteristics different from those of the impedance elements 6 are soldered. The connection is made by the method described above. Here, each wiring may be a power supply wiring, a ground wiring, or the like.

As described above, according to the second embodiment of the present invention, at the connection point between the printed wiring board 1 and the cable, the impedance element 6,
By providing mounting lands 7 and 7 'on which the 6' can be arranged and attaching impedance elements 6 and 6 'corresponding to the characteristic impedance of the cable, standing waves in the cable portion are suppressed. This is because the frequency at which a standing wave occurs depends on the length of the cable, the characteristic impedance, and the like. It can be determined by the positional relationship with the parts.

Therefore, by connecting a predetermined impedance element 6 between the wirings at the connection point between the printed wiring board 1 and the cable, it is possible to suppress radiation noise caused by the standing wave phenomenon occurring in the cable portion. An effect that is effective for

[Third Embodiment] FIG. 3 shows a third embodiment of the present invention.
FIG. 9 is a top view showing a configuration in which a connection portion between a printed wiring board and a cable in the electronic device according to the embodiment of the present invention is enlarged. More specifically, a printed wiring board 1 is provided inside a housing of an electronic device, and a cable for transmitting an electric signal from the printed wiring board 1 to another printed wiring board (not shown). The wiring 3a and the cable wiring 3b are provided. On the printed wiring board 1, the cable wiring 3
a, wiring patterns 4 respectively corresponding to the cable wiring 3b
a, a wiring pattern 4b, a comb-shaped wiring pattern 8 and a connector 5, an impedance element 6
Is installed. Each cable wiring 3a, 3b and wiring patterns 4a, 4b are electrically connected via a connector 5.

Further, mounting lands 7 and 7 'are provided in advance between the wiring pattern 4a and the wiring patterns 4a and 4b, respectively, so that the impedance element 6 and the mounting lands 7 and the wiring patterns 4a and 4a on the wiring pattern 4a are provided. A connection is made between the mounting lands 7 'between the terminals 4b by a method such as soldering. Furthermore, the wiring pattern 4b and the mounting land 7 'are configured to be connected via a comb-shaped wiring pattern 8 having a capacitive property. Here, for example, if an element having an inductance property is selected as the impedance element 6, electrical connection is made as the LC circuit element.

As shown in a first modification of the third embodiment of the present invention shown in FIG. 4, instead of providing the comb-shaped wiring pattern 8 of FIG. 3 between the wiring patterns 4a and 4b, a folded shape is used. The connection may be performed by using the conductor pattern 9 so that the wiring pattern has inductance.

Further, as shown in a second modification of the third embodiment of the present invention in FIG.
The connection may be made by giving the wiring pattern an inductance property by using 0 and the through hole 11.

As described above, according to the third embodiment of the present invention, at the connection point between the printed wiring board 1 and the cable, the mounting land 7 on which the impedance element 6 can be arranged beforehand between the wirings. , 7 ′, and an impedance element 6 corresponding to the characteristic impedance of the cable.
By attaching the cable, standing waves in the cable portion are suppressed. This is because the frequency at which a standing wave occurs depends on the length of the cable, the characteristic impedance, and the like. The characteristic impedance is determined by the dielectric and wiring shape that make up the wiring, the physical positional relationship between the two wirings, and the metal of the housing. It can be determined by the positional relationship with the parts.

Therefore, by connecting a predetermined impedance element 6 between the wirings at the connection point between the printed wiring board 1 and the cable, it is possible to suppress radiation noise caused by the standing wave phenomenon occurring in the cable portion. An effect that is effective for

[Fourth Embodiment] FIG. 6 shows a fourth embodiment of the present invention.
FIG. 9 is a top view showing a configuration in which a connection portion between a printed wiring board and a cable in the electronic device according to the embodiment of the present invention is enlarged. More specifically, a printed wiring board 1 is provided inside a housing of an electronic device, and a cable for transmitting an electric signal from the printed wiring board 1 to another printed wiring board (not shown). Digital signal wiring 3d, ground wiring 3e, and power supply wiring 3f. On the printed wiring board 1, a digital signal wiring pattern 4d, a ground wiring pattern 4e corresponding to the digital signal wiring 3d, the ground wiring 3e, and the power supply wiring 3f of the cable, respectively.
A power supply wiring pattern 4f is provided, and a connector 4, a resistor 6a, a capacitor 6b, and a digital logic circuit (not shown) are mounted. Digital signal wiring 3d, ground wiring 3e, power supply wiring 3 of each cable
f, the digital signal wiring pattern 4d, the ground wiring pattern 4e, and the power supply wiring pattern 4f are electrically connected via the connector 4.

Further, each digital signal wiring pattern 4
d, ground wiring pattern 4e, power supply wiring pattern 4
The mounting lands 7 and 7 'are provided in advance between f and each wiring pattern, and the resistance element 6a and the capacitor 6b having a capacitance are connected by a method such as soldering.
With the above configuration, it is possible to suppress the standing wave phenomenon in the cable portion even if a high-frequency current flows not only in the signal wiring but also in the wiring for other uses. Here, the impedance element may exhibit inductance.

As described above, according to the fourth embodiment of the present invention, at the connection point between the printed wiring board 1 and the cable, the impedance elements (the resistance element 6a and the capacitor 6b) are previously provided between the wirings. By providing mounting lands 7 and 7 'that can be arranged and mounting an impedance element corresponding to the characteristic impedance of the cable, standing waves in the cable portion are suppressed. This is because the frequency at which a standing wave occurs depends on the length of the cable, the characteristic impedance, and the like. The characteristic impedance is determined by the dielectric and wiring shape that make up the wiring, the physical positional relationship between the two wirings, and the metal of the housing. It can be determined by the positional relationship with the parts.

Therefore, by connecting a predetermined impedance element between the wirings at the connection point between the printed wiring board 1 and the cable, it is possible to suppress radiation noise caused by a standing wave phenomenon occurring in the cable portion. It has an effective effect.

[Other Embodiments] The first embodiment of the present invention described above.
In the fourth to fourth embodiments, the connection structure between a printed wiring board and a cable in an electronic device has been described as an example. However, the application of the present invention is not limited to an electronic device alone, and includes a plurality of electronic devices. It is possible to apply to the system which is performed. That is, the present invention can be applied to a connection structure between a printed wiring board and a cable in each of a plurality of electronic devices constituting a system.

[0050]

As described above, according to the printed wiring board and cable connection structure of the first to tenth aspects, two printed wiring boards are connected via an impedance element corresponding to the characteristic impedance between two adjacent cable wirings. It is configured to connect between the wirings, and because the connection structure is configured to be provided between a plurality of wirings, that is, by connecting a predetermined impedance element between the wirings at a connection point between the printed wiring board and the cable. This has an effect that is effective in suppressing radiation noise caused by a standing wave phenomenon occurring in a cable portion.

According to the electronic device of the present invention, the connection structure between the printed wiring board and the cable is applied to the electronic device in the same manner as described above. By connecting a predetermined impedance element between the wirings, there is an effect that is effective in suppressing radiation noise caused by a standing wave phenomenon occurring in the cable portion.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a connection structure between a printed wiring board and a cable in an electronic device according to a first embodiment of the present invention.

FIG. 2 is a top view showing a connection structure between a printed wiring board and a cable in an electronic device according to a second embodiment of the present invention.

FIG. 3 is a top view showing a connection structure between a printed wiring board and a cable in an electronic device according to a third embodiment of the present invention.

FIG. 4 is a top view showing a connection structure between a printed wiring board and a cable in an electronic device according to a first modification of the third embodiment of the present invention.

FIG. 5 is a perspective view showing a connection structure between a printed wiring board and a cable in an electronic device according to a second modification of the third embodiment of the present invention.

FIG. 6 is a top view showing a connection structure between a printed wiring board and a cable in an electronic device according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view showing a connection structure between a printed wiring board and a cable in an electronic device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printed wiring board 2 Housing metal part 3a, 3b Cable wiring 3d Cable digital signal wiring 3e Cable ground wiring 3f Cable power wiring 4a, 4b wiring pattern 4d Digital signal wiring pattern 4e Ground wiring pattern 4f Power wiring pattern 5 Connector 6, 6 'Impedance element 6a Resistance element 6b Capacitor 7, 7' Mounting land 8 Comb-shaped wiring pattern 9 Turned-shaped conductor pattern 10 Spiral-shaped conductor pattern 11 Through hole

Claims (20)

[Claims] 1. A printed wiring board applied to an electronic device having at least two printed wiring boards and a cable having a plurality of wirings for transmitting an electric signal between the two printed wiring boards inside a housing. A connection structure between a printed wiring board and a cable, wherein the two wirings are connected via an impedance element corresponding to a characteristic impedance between two adjacent cable wirings. 2. The connection structure between a printed wiring board and a cable according to claim 1, wherein said impedance element has a resistance. 3. The connection structure between a printed wiring board and a cable according to claim 1, wherein the impedance element has resistance and capacitance. 4. The connection structure between a printed wiring board and a cable according to claim 1, wherein the impedance element has resistance, capacitance, and inductance. 5. The connection structure between a printed wiring board and a cable according to claim 1, wherein said printed wiring board includes a digital logic circuit, and said two wirings are a wiring for a digital logic signal and a wiring for a ground. . 6. A connection structure between a printed wiring board and a cable according to claim 1, wherein said two wirings are a power supply wiring and a ground wiring, and said impedance element has resistance and capacitance. . 7. The connection structure between a printed wiring board and a cable according to claim 4, wherein said inductance property is constituted by a folded wiring pattern. 8. The connection structure between a printed wiring board and a cable according to claim 4, wherein said inductance is constituted by a spiral wiring pattern. 9. The connection structure between a printed wiring board and a cable according to claim 4, wherein said capacitance is constituted by a comb-shaped wiring pattern. 10. The connection structure between a printed wiring board and a cable according to claim 1, wherein said connection structure is provided between a plurality of wirings. 11. At least two printed wiring boards,
An electronic device in which a cable provided with a plurality of wires for transmitting an electric signal between the two printed wiring boards is mounted in a housing, wherein the cable includes an impedance element corresponding to a characteristic impedance between two adjacent cable wires. An electronic device characterized by connecting two wirings. 12. The electronic device according to claim 11, wherein the impedance element has a resistance. 13. The electronic device according to claim 11, wherein the impedance element has a resistance and a capacitance. 14. The electronic device according to claim 11, wherein the impedance element has resistance, capacitance, and inductance. 15. The electronic device according to claim 11, wherein the printed wiring board includes a digital logic circuit, and the two wirings are a digital logic signal wiring and a ground wiring. 16. The electronic device according to claim 11, wherein the two wirings are a power supply wiring and a ground wiring, and the impedance element has resistance and capacitance. 17. The semiconductor device according to claim 1, wherein the inductance is formed by a folded wiring pattern.
4. The electronic device according to 4. 18. The electronic device according to claim 14, wherein the inductance is formed by a spiral wiring pattern. 19. The electronic device according to claim 14, wherein the capacitive element is configured by a comb-shaped wiring pattern. 20. The electronic device according to claim 11, wherein the connection structure is provided between a plurality of wirings.