JPH11145569A - Printed wiring board and its design method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize a printed wiring board in which generation of radiation noise is suppressed by suppressing generation of standing waves. A plurality of conductor patterns (2a) extending in the longitudinal direction of the base material (1) and signal wirings (5a) are formed on a component surface of a rectangular plate-shaped base material (1). A plurality of conductor patterns 2b and signal wires 5b extending in a direction perpendicular to the longitudinal direction of the base material are formed on a solder surface of the base material 1 opposite to the component surface. The conductor patterns 2a and 2b are used as a power supply pattern or a ground pattern. Conductor pattern 2a
And 2b are separated into two parts, and the conductor pattern 2a
And 2b are separated from each other by chip-type resistor 4
Connected via Thus, a decrease in the impedance of the conductor patterns 2a and 2b at the frequency of the standing wave generated from the relationship between the size of the substrate and the wavelength of the radiation noise is suppressed by the loss of the chip-type resistor 4, and the resonance of the standing wave is suppressed. Is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printed wiring board and a method for designing the same.

[0002]

2. Description of the Related Art In a conventional printed wiring board, a power supply pattern or a ground pattern (hereinafter referred to as a GND pattern) is used to reduce a current loop in order to prevent adverse effects due to radiation noise or to reduce a potential fluctuation of a power supply system. ), Or a power supply layer or a ground layer is formed in an inner layer of a printed wiring board. By designing these printed wiring boards, a power supply pattern or a GND pattern having a low impedance is formed uniformly on the entire printed wiring board.

On the other hand, in order to further suppress radiation noise generated from the printed wiring board, it is often the case that the ground of the printed wiring board is electrically connected to a conductive housing to strengthen the ground of the printed wiring board. Done.

[0004]

However, when a uniform power supply pattern or GND pattern is provided on the entire printed wiring board, or when the GND pattern is electrically connected to the conductive casing. In this case, the peak of the standing wave may occur. The peak of the standing wave is caused by the size of the printed wiring board or the distance between the printed wiring board and the housing at the connection portion when the GND pattern of the printed wiring board is electrically connected to the housing. . This standing wave occurs when the length or width of the printed wiring board is equivalent to λ / 4 or λ / 2, where λ is the wavelength of the radiation noise. Also, the frequency of the standing wave is actually the size of the printed wiring board, the distance between the printed wiring board and the housing at the connection between the GND pattern of the printed wiring board and the housing,
It is determined by the effective dielectric constant of the conductor of the printed wiring board and the surrounding dielectric surrounding the housing. Here, even if the size of the printed wiring board, the distance between the printed wiring board and the housing, or the material or thickness of the surrounding dielectric material is changed, only the frequency of the standing wave shifts. However, there is a problem that high peak radiation noise exists at any frequency of the standing wave.

An object of the present invention is to provide a printed wiring board in which generation of radiated noise is suppressed by suppressing generation of a standing wave, and a design method thereof.

[0006]

Means for Solving the Problems The present invention for achieving the above object provides a plate-like base material, and a plate-like base material formed on the plate-like base material.
In a printed wiring board including a power supply pattern or a conductor pattern used as a ground pattern, the conductor pattern is separated at a predetermined location, and the separated portions of the conductor pattern are connected via a circuit element with heat loss. It is characterized by being connected.

In the above invention, since the separated portions of the conductor pattern are connected to each other via the circuit element with heat loss, the length of the base material in the direction in which the separated portions of the conductor pattern are lined up. And the impedance of the conductor pattern at the frequency of the standing wave generated due to the relationship with the wavelength of the radiation noise is suppressed by the loss of the circuit element, and the Q value of the resonance of the standing wave is suppressed. Thereby, the generation of the standing wave is suppressed, the high-frequency current flowing through the conductor pattern is suppressed, and the radiation noise generated from the printed wiring board is suppressed.

It is preferable that a signal line for a clock is formed on the plate-shaped base material, and the conductor pattern is separated at a portion of the conductor pattern other than a portion near the signal line.

As described above, the conductor pattern is separated at a portion other than the portion near the signal line of the conductor pattern, and the portion of the conductor pattern near the signal line is not separated. In this part, the return current flowing through the conductor pattern due to the signal of the signal line can return without any obstacle. Therefore, an increase in radiation noise due to the charging current of the conductor pattern is suppressed.

The shape of the plate-shaped base material is rectangular, and the separated portions of the conductor pattern are arranged in the longitudinal direction of the plate-shaped base material, or the plate-shaped base material is Preferably, the conductor patterns are separated so as to be arranged in a direction perpendicular to the longitudinal direction of the conductor pattern.

As described above, the conductor pattern is separated so that the separated portions of the conductor pattern are arranged in the longitudinal direction of the base material, and the separated portions of the conductor pattern are connected via the circuit element. Accordingly, the generation of a standing wave due to the relationship between the length of the base material in the longitudinal direction and the wavelength of the radiation noise is suppressed, and the radiation noise generated from the printed wiring board is largely suppressed. Further, when the standing wave generated by the relationship between the length of the base material in the direction perpendicular to the longitudinal direction and the wavelength of the radiated noise is problematic in the relationship of the frequency, as described above, the conductor pattern is used. The conductive pattern is separated such that the separated portions are arranged in a direction perpendicular to the longitudinal direction of the base material. Then, by connecting the separated portions of the conductor pattern via circuit elements, the generation of radiation noise from the printed wiring board is suppressed.

In addition, a resistor is used as the circuit element, and the resistor is formed at the predetermined location where the conductor pattern is separated, and a resistance value of the resistor is set at the position of the predetermined location. Is preferably different depending on Furthermore, it is preferable that the resistance value of the resistor is larger as the position of the resistor is closer to the outer periphery of the plate-shaped substrate. Further, it is preferable that the resistor is of a lead type or a chip type, or is formed by printing.

Further, a ferrite element is used as the circuit element, and the ferrite element is formed at the predetermined location where the conductor pattern is separated, and an inductance value of the ferrite element is adjusted at the position of the predetermined location. Is preferably different depending on Further, it is preferable that the inductance value of the ferrite element is larger as the position of the ferrite element is closer to the outer periphery of the plate-shaped base material. Further, it is preferable that the ferrite element is a lead type or a chip type.

As described above, since the resistance value of the resistor and the inductance value of the ferrite element differ depending on the position where these circuit elements are formed, it is possible to effectively suppress the generation of standing waves. it can.

Further, as described above, the resistance value of the resistor,
Since the inductance value of the ferrite element is larger as the position of the circuit element is closer to the outer periphery of the base material, the generation of the standing wave can be suppressed efficiently.

Furthermore, it is preferable that a plane pattern used for power supply or ground is formed on one surface or an inner layer of the plate-shaped base material, and the plane pattern is separated at a predetermined position.

As described above, since the plane pattern formed on the base material is separated at a predetermined position,
The generation of a standing wave due to the relationship between the length of the base material in the direction in which the separated portions of the plain pattern are arranged and the wavelength of the radiation noise is suppressed.

Further, a clock signal line passing near the separated portion of the plane pattern is formed on the plate-shaped substrate, and the separated portions of the plane pattern are connected to each other. It is preferable that the connection is made electrically in the vicinity of the signal line by a connection portion made of the same material as the plain pattern.

As described above, the separated plane-shaped patterns are electrically connected to each other in the vicinity of the signal line by a connection portion made of the same material as that of the plane-shaped pattern. The return current flowing in the pattern passes through the connection, and the return current returns without any obstacles. Therefore, an increase in radiation noise due to the charging current of the plain pattern is suppressed.

Further, the shape of the plate-shaped substrate is rectangular, and the separated portion of the plane pattern is
It is preferable that the plane patterns are separated so as to be arranged in the longitudinal direction of the plate-shaped base material or in the direction perpendicular to the longitudinal direction of the plate-shaped base material.

The present invention also provides a method for designing a printed wiring board including a plate-shaped base material and a conductor pattern formed on the plate-shaped base material and used as a power supply pattern or a ground pattern. And a step of connecting the separated portions of the conductor pattern via a circuit element with heat loss.

In the above invention, it is possible to design a printed wiring board in which the generation of radiation noise as described above is suppressed.

The method may further include the step of forming a clock signal line on the plate-like base material.
It is preferable that the conductor pattern is separated at a portion excluding a portion near the signal line.

As described above, by separating the conductor pattern, the return current flowing through the conductor pattern by the signal of the signal line can be fed back without any obstacle, and the increase of the radiation noise due to the charging current of the conductor pattern is reduced. A suppressed printed wiring board can be designed.

The shape of the plate-like base material is rectangular, and the separated portions of the conductor pattern are arranged in the longitudinal direction of the plate-like base material, or the plate-like base material is Preferably, the conductor patterns are separated so as to be arranged in a direction perpendicular to the longitudinal direction of the material.

As described above, the conductor pattern is separated such that the separated portions of the conductor pattern are arranged in the longitudinal direction of the base material, and the separated portions of the conductor pattern are connected to each other via the circuit element. This makes it possible to design a printed wiring board in which the generation of standing waves due to the relationship between the length of the base material in the longitudinal direction and the wavelength of radiation noise is suppressed.
As described above, the conductor pattern is separated such that the separated portions are arranged in the longitudinal direction of the base material, and the separated portions of the conductor pattern are connected to each other via a circuit element. It is possible to design a printed wiring board in which generation of radiation noise is significantly suppressed. Further, when the standing wave generated by the relationship between the length of the base material in the direction perpendicular to the longitudinal direction and the wavelength of the radiated noise is problematic in the relationship of the frequency, as described above, the conductor pattern is used. The conductive pattern is separated such that the separated portions are arranged in a direction perpendicular to the longitudinal direction of the base material. Then, by connecting the separated portions of the conductor pattern via circuit elements, the generation of radiation noise from the printed wiring board is suppressed.

Further, a resistor is used as the circuit element,
Preferably, the position where the resistor is formed is the predetermined location where the conductor pattern is separated, and the resistance value of the resistor varies according to the location of the predetermined location.
Furthermore, it is preferable that the resistance value of the resistor is larger as the position of the resistor is closer to the outer periphery of the plate-shaped substrate.
Further, it is preferable that the resistor is of a lead type or a chip type, or is formed by printing.

Further, a ferrite element is used as the circuit element, and the position where the ferrite element is formed is the predetermined location where the conductor pattern is separated, and the inductance value of the ferrite element is the same as the predetermined location. Preferably, it differs depending on the position. Further, it is preferable that the inductance value of the ferrite element is larger as the position of the ferrite element is closer to the outer periphery of the plate-shaped base material. Further, it is preferable that the ferrite element is a lead type or a chip type.

Further, the method further includes a step of forming a plane pattern used for power supply or ground on one surface or an inner layer of the plate-like base material, and a step of separating the plane pattern at a predetermined position. Is preferred.

Further, a step of forming a clock signal line passing near the separated portion of the plane pattern on the plate-like base material, and forming the separated portions of the plane pattern together. And electrically connecting in the vicinity of the signal line by a connection portion made of the same material as that of the plane pattern.

The shape of the plate-shaped base material is rectangular, and the separated portions of the plane pattern are arranged in the longitudinal direction of the plate-shaped base material. It is preferable that the plain patterns are separated so as to be arranged in a direction perpendicular to the longitudinal direction of the substrate.

[0032]

Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a plan view showing a printed wiring board according to a first embodiment of the present invention. As the printed wiring board of the present embodiment, a two-layer printed wiring board formed by forming a conductor layer on each of the front and back surfaces of a plate-shaped base material is used. FIG. 1A is a plan view showing a component surface of the printed wiring board, and FIG. 1B is a plan view showing a solder surface of the printed wiring board opposite to the component surface.

In the printed wiring board of this embodiment, FIG.
As shown in (a), a plurality of conductor patterns 2a and signal wirings 5a extending in the longitudinal direction of the base 1 are formed on the component surface of the base 1 having a rectangular plate shape. Conductor pattern 2
a is used as a power supply pattern or a ground pattern. Via holes 3 are formed at predetermined positions of the respective conductor patterns 2a at specific intervals in the longitudinal direction of the base material 1.

Each of the conductor patterns 2a is separated into two parts at a substantially middle position of the conductor pattern 2a. Therefore, the conductor patterns 2a are separated such that the separated portions of the conductor patterns 2a are arranged in the longitudinal direction of the base material 1. A chip land is formed between two separated portions of each conductor pattern 2a, and a chip resistor 4 which is a circuit element with heat loss is mounted on each chip land. Through the chip-type resistor 4, the separated portions of the conductor pattern 2a are connected together with the loss of the chip-type resistor 4. Thus, a decrease in the impedance of the conductor pattern 2a at the frequency of the standing wave generated due to the relationship between the length of the base material 1 in the longitudinal direction and the wavelength of the radiation noise is suppressed by the loss of the chip-type resistor 4, and the constant The Q value of the resonance of the standing wave is suppressed.

As shown in FIG. 1B, a plurality of conductor patterns 2b and signal wires 5b extending in a direction perpendicular to the longitudinal direction of the substrate 1 are formed on the solder surface of the substrate 1. The conductor pattern 2b and the signal wiring 5b and the conductor pattern 2
B and the conductor pattern 2b and the signal wiring 5b perpendicular to the signal wiring 5b form a girder structure. The conductor pattern 2b is also used as a power supply pattern or a ground pattern similarly to the conductor pattern 1a. Each conductor pattern 2b is connected to the conductor pattern 2a through the via hole 3.
Is electrically connected to

Each conductor pattern 2b is separated into two parts at predetermined positions. A chip land is formed between the two separated portions of each conductor pattern 2b.
A chip-type resistor 4 which is a circuit element with heat loss is mounted. The separated portions of the respective conductor patterns 2b are connected to each other with the loss of the chip resistor 4 via the chip resistor 4. Thereby, the substrate 1
Of the conductor pattern 2b at the frequency of the standing wave generated due to the relationship between the length in the direction perpendicular to the longitudinal direction and the wavelength of the radiation noise.
And the Q value of the resonance of the standing wave is suppressed.

As described above, each of the conductor patterns 2a
And 2b, the separated portions are connected via the chip-type resistor 4, so that the size of the base 1 and
The decrease in the impedance of the conductor patterns 2a and 2b at the frequency of the standing wave generated due to the relationship with the wavelength of the radiation noise is suppressed by the loss of the chip-type resistor 4, and the Q value of the resonance of the standing wave is suppressed. Thereby, the generation of the standing wave is suppressed, and the conductor pattern 2 in this state is suppressed.
The high frequency currents a and 2b are suppressed. As a result, an increase in radiation noise generated from the printed wiring board is suppressed.

(Second Embodiment) FIG. 2 is a plan view showing a printed wiring board according to a second embodiment of the present invention. As the printed wiring board of the present embodiment, a two-layer printed wiring board formed by forming a conductor layer on each of the front and back surfaces of a plate-shaped base material is used. FIG. 2A is a plan view illustrating a component surface of the printed wiring board, and FIG. 2B is a plan view illustrating a solder surface of the printed wiring board opposite to the component surface.

In the printed wiring board of this embodiment, FIG.
As shown in (a), the ICs 16a, 16b, and 16c are mounted at different positions on the component surface of the base material 11 having a rectangular plate shape. A conductor pattern 12a is formed on the component surface of the base material 11. The conductive pattern 12a is formed at the short side end of the base material 11 by the base material 11a.
And a plurality of conductor portions extending in the longitudinal direction of the base material 11. A plurality of via holes 13 are formed in the conductor pattern 12a at predetermined intervals. The conductor pattern 12a is used as a power supply pattern or a ground pattern.

Further, the IC 16 is provided on the component side of the base material 11.
A clock signal line 17a extending in the longitudinal direction of the base material 11 is formed from each of a, 16b, and 16c. Via holes 18 are formed at predetermined positions of the clock signal line 17a.

Some of the plurality of conductor portions of the conductor pattern 12a extending in the longitudinal direction of the substrate 11
1 at approximately the middle in the longitudinal direction. That is,
The conductive pattern (12a) is separated such that the separated portions of the conductive pattern (12a) are arranged in the longitudinal direction of the substrate (11). However, among the plurality of conductor portions of the conductor pattern 12a extending in the longitudinal direction of the base material 11, the clock signal line 17
The portion extending in parallel with the clock signal line 17a in the vicinity of a is not separated. Substrate 1 of conductor pattern 12a
The conductor portion extending in a direction parallel to the short side of the first is also separated at a predetermined position.

Chip lands are formed between the separated conductor portions of the conductor pattern 12a, as in the first embodiment, and chip resistors 14 are mounted on those chip lands. Via the chip-type resistor 14, the separated conductor portions of the conductor pattern 12a are connected together with the loss of the chip-type resistor 14. Accordingly, the impedance of the conductor pattern 12a at the frequency of the standing wave generated due to the relationship between the length of the base material 11 in the longitudinal direction and the wavelength of the radiation noise is reduced.
4, and the Q value of the resonance of the standing wave is suppressed.

On the other hand, as shown in FIG.
The conductor pattern 12b is formed as shown in FIG. The conductor pattern 12b is formed at the end of the long side of the base 11 by the base 1
It is composed of a conductor portion extending in a direction parallel to one long side and a plurality of conductor portions extending in a direction perpendicular to the longitudinal direction of the base material 11. The conductor pattern 12b is electrically connected to the conductor pattern 12a via a plurality of via holes 13, and is used as a power supply pattern or a ground pattern.

At a predetermined position on the solder surface of the base 11, a clock signal line 17b extending in a direction perpendicular to the longitudinal direction of the base 11 is formed. Clock signal line 17b
Are electrically connected to the clock signal line 17a via via holes 18.

Some of the plurality of conductor portions of the conductor pattern 12b extending in the direction perpendicular to the longitudinal direction of the base material 11 and the conductor portion extending in the direction parallel to the long side of the base material 11 are formed at predetermined positions. Are separated. However, of the plurality of conductor portions of the conductor pattern 12b extending in a direction perpendicular to the longitudinal direction of the base material 11, the conductor portions extending in parallel with the clock signal line 17b near the clock signal line 17b are not separated. .

Chip lands are formed between the separated conductor portions of the conductor pattern 12b as in the first embodiment, and the chip resistors 14 are mounted on these chip lands. Via the chip-type resistor 14, the separated conductor portions of the conductor pattern 12b are connected together with the loss of the chip-type resistor 14. This allows
The decrease in the impedance of the conductor pattern 12b at the frequency of the standing wave generated by the relationship between the length of the base material 11 in the direction perpendicular to the longitudinal direction and the wavelength of the radiation noise is suppressed by the loss of the chip-type resistor 14, The Q value of the resonance of the standing wave is suppressed.

As described above, in the printed wiring board of the present embodiment, the separated conductor portions of the conductor patterns 12a and 12b are connected via the chip-type resistor 14. As a result, a decrease in the impedance of the conductor patterns 12a and 12b at the frequency of the standing wave caused by the relationship between the size of the base material 11 and the wavelength of the radiation noise is suppressed by the loss of the chip-type resistor 14, and the standing The Q value of wave resonance is suppressed. Accordingly, the generation of the standing wave is suppressed, and the conductor patterns 12a and 1a in this state are suppressed.
The high frequency current of 2b is suppressed. As a result, an increase in radiation noise from the printed wiring board is suppressed.

In addition, the conductor patterns 12a and 12b
Since the conductor portions near the clock signal line 17a or 17b are not separated, the conductor patterns 12a and 12b
The return current flowing through the unseparated conductor portion b returns without any obstacle. Thereby, the clock signal line 1
Conductor pattern 12a by high-speed signal of 7a or 17b
And 12b, the increase in radiation noise caused by the charging current is suppressed.

(Third Embodiment) FIGS. 3 and 4 are views for explaining a printed wiring board according to a third embodiment of the present invention. As the printed wiring board of the present embodiment, a four-layer printed wiring board in which a conductive layer is formed on each of the front and back surfaces of a plate-shaped base material and two conductive layers are formed on an inner layer of the base material Is used.

FIG. 3A is a plan view showing a component surface of the printed wiring board, and FIG. 3A is a diagram showing a pattern of an inner layer on the component surface side of the printed wiring board. FIG. 4C is a diagram showing a pattern of an inner layer on a surface side of the printed wiring board opposite to the component surface, and FIG. 4D is a diagram showing a solder surface of the printed wiring board on the side opposite to the component surface. FIG.

In the printed wiring board of this embodiment, FIG.
As shown in (a), a conductor pattern 22a and a signal wiring 25a are formed on a component surface of a base material 21 having a rectangular plate shape. The conductor pattern 22a includes a plurality of conductor portions extending in the longitudinal direction of the base 21. The signal wiring 25a is located at a position different from the conductor pattern 22a.
In the longitudinal direction. Via holes 23 are formed at predetermined positions of the conductor pattern 22a. The conductor pattern 22a is used as a power supply pattern or a ground pattern.

Of the plurality of conductor portions of the conductor pattern 22a, the conductor portion passing substantially in the middle of the base member 21 in the longitudinal direction is:
The substrate 21 is separated at substantially the middle in the longitudinal direction. A chip land is formed between the separated conductor portions of the conductor pattern 22a, and a chip resistor 24 as a circuit element with heat loss is mounted on the chip land.
Via the chip type resistor 24, the conductor pattern 22a
The separated conductor portions are connected together with the loss of the chip-type resistor 24. As a result, a decrease in the impedance of the conductor pattern 22a at the frequency of the standing wave generated due to the relationship between the length of the base material 21 in the longitudinal direction and the wavelength of the radiation noise is suppressed by the loss of the chip-type resistor 24. The Q value of the resonance of the standing wave is suppressed.

The inner layer on the component side of the substrate 21 has a structure shown in FIG.
As shown in (b), an inner solid pattern 29a is formed as a plain pattern. The inner layer solid pattern 29a is completely separated into two parts at predetermined positions by a separation part 30a extending in a direction perpendicular to the longitudinal direction of the base material 21. Therefore, the inner layer solid pattern 29a
The inner solid pattern 29a is separated such that the separated portions are arranged in the longitudinal direction of the base 21. The inner layer solid pattern 29a is used as a power supply pattern or a ground pattern. Each via hole 23 penetrates such an inner layer solid pattern 29a, and each via hole 23 and the inner layer solid pattern 29a are electrically connected.

As shown in FIG. 4C, an inner layer solid pattern 29b as a plain pattern is formed on the inner layer on the solder side of the base material 21. The inner layer solid pattern 29b includes a separation portion 30 extending in the longitudinal direction of the base material 21.
b completely separates it into two parts at a predetermined location. Each via hole 23 penetrates such an inner layer solid pattern 29b, and each via hole 23 and the inner layer solid pattern 29b are electrically connected. The inner layer solid pattern 29b is used as a power supply pattern or a ground pattern.

As shown in FIG. 4D, a conductor pattern 22b and a signal wiring 25b are formed on the solder surface of the base 21. The conductor pattern 22b is composed of a plurality of conductor portions extending in a direction perpendicular to the longitudinal direction of the base 21. The signal wiring 25b extends in a direction different from the conductor pattern 22b in a direction perpendicular to the longitudinal direction of the base 21. The conductor pattern 22b is electrically connected to the conductor pattern 22a via the via hole 23, and is used as a power supply pattern or a ground pattern. Some of the plurality of conductor portions of the conductor pattern 22b are separated into two conductor portions at predetermined positions.

A chip land is formed between the two separated conductor portions of the conductor pattern 22b, and a chip resistor 24 is mounted on the chip land. Via the chip-type resistor 24, the separated conductor portions of the conductor pattern 22b are connected together with the loss of the chip-type resistor 24. As a result, the impedance of the conductor pattern 22 b at the frequency of the standing wave generated due to the relationship between the length of the substrate 21 in the direction perpendicular to the longitudinal direction and the wavelength of the radiation noise is reduced by the loss of the chip-type resistor 24. The Q value of resonance of the standing wave is suppressed.

In such a printed wiring board, the inner layer solid pattern 29a and the inner layer solid pattern 29b have a bridging structure in which they are electrically connected via the via holes 23, and the via holes 23 have an inductance property. I have. As a result, the via hole 23 exhibits high impedance characteristics at high frequencies. However, since the inner layer solid pattern 29a is separated, generation of a standing wave due to the relationship between the length of the base material 21 in the longitudinal direction and the wavelength of radiation noise is suppressed. Similarly, since the inner solid pattern 29b is separated, the substrate 21
The generation of a standing wave caused by the relationship between the length in the direction perpendicular to the longitudinal direction and the wavelength of the radiation noise can be suppressed. At the same time, the high-frequency current of the conductor patterns 22a and 22b is suppressed, and as a result, an increase in noise radiated from the printed wiring board is suppressed.

As described above, in the printed wiring board of the present embodiment, the conductor patterns 22a and 22b are partially separated, and the separated conductor portions of the conductor patterns 22a and 22b are connected by the chip-type resistor 24. ing. As a result, a decrease in the impedance of the conductor patterns 22a and 22b at the frequency of the standing wave generated due to the relationship between the size of the substrate 21 and the wavelength of the radiation noise is suppressed by the loss of the chip-type resistor 24, The Q value of wave resonance is suppressed. Therefore, the generation of the standing wave is suppressed, and the high-frequency current of the conductor patterns 22a and 22b is suppressed. As a result, an increase in radiation noise from the printed wiring board is suppressed.

The inner layer solid patterns 29a and 29b
Are separated, the generation of a standing wave is suppressed, and the increase in radiation noise is suppressed.

(Fourth Embodiment) FIGS. 5 and 6 are views for explaining a printed wiring board according to a fourth embodiment of the present invention. As the printed wiring board of the present embodiment, a four-layer printed wiring board in which a conductive layer is formed on each of the front and back surfaces of a plate-shaped base material and two conductive layers are formed on an inner layer of the base material Is used.

FIG. 5A is a plan view showing a component surface of the printed wiring board, and FIG. 5B is a diagram showing a pattern of an inner layer on the component surface side of the printed wiring board. FIG. 6C is a diagram showing a pattern of an inner layer of the printed wiring board on the side opposite to the component side, and FIG. 6D is a view showing a solder surface of the printed wiring board on the side opposite to the component side. FIG.

In the printed wiring board of this embodiment, FIG.
As shown in (a), ICs 36a, 36b, and 36c are mounted at different positions on the component surface of a base 31 having a rectangular plate shape. A conductor pattern 32a is formed on the component surface of the base 31. The conductor pattern 32a is composed of a plurality of conductor portions extending in the longitudinal direction of the base material 31, and is used as a power supply pattern or a ground pattern.

Further, the IC 36
A clock signal line 37a extending in the longitudinal direction of the base material 31 is formed from each of a, 36b, and 36c. A via hole 38 is formed at a predetermined position of the clock signal line 37a.

Some of the conductor portions of the conductor pattern 32a are separated substantially at the center of the base material 31 in the longitudinal direction. However, among the plurality of conductor portions of the conductor pattern 32a, the clock signal line 37 is located near the clock signal line 37a.
The conductor portions extending parallel to a are not separated.

A chip land is formed between the separated conductor portions of the conductor pattern 32a, and a chip resistor 34 as a circuit element with heat loss is mounted on the chip land. Through the chip-type resistor 34, the separated conductor portions of the conductor pattern 32a are connected together with the loss of the chip-type resistor 34. As a result, the impedance of the conductor pattern 32a at the frequency of the standing wave generated due to the relationship between the length of the base material 31 in the longitudinal direction and the wavelength of the radiation noise is reduced.
4, and the Q value of the resonance of the standing wave is suppressed.

As shown in FIG. 5, the inner layer
As shown in (b), an inner solid pattern 39a as a plain pattern is formed. The inner layer solid pattern 39a is used as a power supply pattern or a ground pattern. The inner layer solid pattern 39a includes separation portions 40a, 40 extending in a direction perpendicular to the longitudinal direction of the base material 31.
b and 40c separate them at predetermined locations. The separation portions 40a, 40b, and 40c are arranged in this order in a direction perpendicular to the longitudinal direction of the substrate 31. In a portion sandwiched between the separation portion 40a and the separation portion 40b, a connection portion 42a of the same material as the conductor of the inner solid pattern 39a is formed. A connection portion 42b made of the same material as the conductor of the inner solid pattern 39a is also formed between the separation portion 40b and the separation portion 40c.

The separated portions of the inner layer solid pattern 39a are electrically connected to each other via the connection portions 42a and 42b. The connection portions 42a and 42b are portions near the clock signal line 37a. Therefore, the inner layer solid pattern 39a is generated by the high-speed signal of the clock signal line 37a.
Return current flowing through the connection portions 42a and 42b returns without any obstacle. Therefore, an increase in radiation noise due to the charging current of the inner layer solid pattern 39a is suppressed.

In the inner layer solid pattern 39a, the via hole 33 penetrates, and the inner layer solid pattern 39a and the via hole 33 are electrically connected. Further, in the portion of the inner layer solid pattern 39a through which the via hole 38 penetrates, a via hole clearance 41a having a hole larger than the via hole 38 is formed. When the via hole 38 penetrates the inside of the via hole clearance 41a, the via hole 38 becomes the inner layer solid pattern 39.
a.

The inner layer on the solder side of the base material 31 has a structure shown in FIG.
As shown in (c), an inner solid pattern 39b as a plain pattern is formed. The inner layer solid pattern 39b is used as a power supply pattern or a ground pattern. The inner layer solid pattern 39b is separated at predetermined locations by separation portions 40d, 40e, and 40f extending in the longitudinal direction of the base material 31. Separation portions 40d, 40
e and 40f are arranged in this order in the longitudinal direction of the base material 31.

Also in the inner layer solid pattern 39b, the via hole 33 penetrates similarly to the inner layer solid pattern 39a, and the inner layer solid pattern 39b and the via hole 33 are electrically connected. Also, the inner layer solid pattern 39b
In the portion where the via hole 38 penetrates, a via hole clearance 41 of a hole larger than the via hole 38 is provided.
b is formed. Via hole clearance 41b
The via hole 38 penetrates through the inside, so that the via hole 38 is insulated from the inner layer solid pattern 39b.

A connection part 42c is formed between the separation part 40d and the separation part 40e, and a connection part 42d is formed between the separation part 40e and the separation part 40f. The connection portions 42c and 42d are formed of the same material as the inner layer solid pattern 39b. The connection portions 42c and 42
The separated portions of the inner-layer solid pattern 39b are electrically connected to each other via d. Therefore, the return current flowing in the inner layer solid pattern 39b by the high-speed signal of the clock signal line 37b passes through the connection portions 42c and 42d and returns without any obstacle. Therefore, the inner layer solid pattern 3
An increase in radiation noise due to the charging current of 9b is suppressed.

As shown in FIG. 6D, a conductor pattern 32b is formed on the solder surface of the base 31. The conductor pattern 32b is constituted by a plurality of conductor portions extending in a direction perpendicular to the longitudinal direction of the base material 31, and the via holes 3
3, and is electrically connected to the conductor pattern 32a. The conductor pattern 32b is used as a power supply pattern or a ground pattern. Further, a clock signal line 37b extending in a direction perpendicular to the longitudinal direction of the base material 31 is formed on the solder surface of the base material 31 at a position different from the conductor pattern 32b. The clock signal line 37b is electrically connected to the clock signal line 37a via the via hole 38.

Some of the plurality of conductor portions of the conductor pattern 32b are separated into two conductor portions at predetermined positions. A chip land is formed between two separated conductor portions of the conductor pattern 32b, and a chip resistor 34 is mounted on the chip land. Through the chip-type resistor 34, the separated conductor portions of the conductor pattern 32b are connected together with the loss of the chip-type resistor 34. Accordingly, the impedance of the conductor pattern 32b at the frequency of the standing wave generated due to the relationship between the length of the base material 31 in the direction perpendicular to the longitudinal direction and the wavelength of the radiation noise is reduced by the loss of the chip-type resistor 34. The Q value of resonance of the standing wave is suppressed.

As described above, in the printed wiring board of the present embodiment, the separated conductor portions of the conductor patterns 32a and 32b are connected to each other through the chip-type resistor 34 so that A decrease in the impedance of the conductor patterns 32a and 32b at the frequency of the standing wave generated due to the relationship between the size and the wavelength of the radiation noise is suppressed by the loss of the chip resistor 34, and the Q value of the resonance of the standing wave is suppressed. Can be Therefore, the generation of the standing wave is suppressed, and the high-frequency current of the conductor patterns 32a and 32b is suppressed. As a result, an increase in radiation noise from the printed wiring board is suppressed.

The inner layer solid patterns 39a and 39b
Are separated, the generation of a standing wave is suppressed, and the increase in radiation noise is suppressed.

Further, the inner layer solid patterns 39a and 39a
b, the separated portions are electrically connected by the connection portion at a position near the clock signal line 37a or 37b, so that the high-speed signals of the respective clock signal lines flow to the inner layer solid patterns 39a and 39b. The return current returns without any obstacles. Therefore, an increase in radiation noise due to the charging current of the inner solid pattern 39a or 39b is suppressed.

In the first to fourth embodiments described above, the separated conductor portions of the conductor pattern are connected via the chip-type resistor, but instead of the chip-type resistor, A lead-type resistor may be used. Further, instead of the chip-type resistor, a resistor formed on the base material by printing may be used. Further, a chip-type or lead-type ferrite element may be used instead of the chip-type resistor.

In the first to fourth embodiments, a plurality of the same resistors are used on each surface of the base material.
This is not necessary, and resistors having different resistance values depending on the positions where the resistors are mounted may be used at respective locations. Thus, by changing the resistance value of the resistor according to the location of the base material, the generation of standing waves can be effectively suppressed. In this case, by increasing the resistance value of the resistor as the position of the resistor is closer to the outer periphery of the base material, the generation of standing waves can be efficiently suppressed. Even when using a ferrite element instead of a resistor, by changing the inductance value of the ferrite element according to the location of the base material,
The generation of a standing wave can be effectively suppressed. And
As in the case of the resistor, by increasing the inductance value of the ferrite element as the position of the ferrite element is closer to the outer periphery of the base material, the generation of standing waves can be suppressed efficiently.

Further, in the first to fourth embodiments, the direction of the wiring on the component surface of the rectangular base is defined as the longitudinal direction of the base,
Although the direction of the wiring on the solder side of the substrate is the direction perpendicular to the longitudinal direction of the substrate, the direction of the wiring on the component side is the direction perpendicular to the longitudinal direction of the substrate, and the direction of the wiring on the solder side is the base. It may be in the longitudinal direction of the material. Alternatively, the wiring direction may be partially different on each surface of the base material.

[0081]

As described above, according to the present invention, the separated portions of the conductor pattern used as the power supply pattern or the ground pattern are connected to each other via the circuit element with heat loss. In addition to suppressing the standing wave generated due to the relationship between the length of the base material in the direction in which the separated portions are arranged and the radiation noise, the high-frequency current of the conductor pattern is suppressed, and the radiation noise from the printed wiring board is reduced. This has the effect of being suppressed.

Further, since the conductor pattern is separated at a portion other than the portion near the clock signal line of the conductor pattern, and the portion of the conductor pattern near the signal line is not separated, the conductor pattern is separated. The return current of the conductor pattern due to the signal returns without any obstacle. Therefore, there is an effect that an increase in radiation noise due to the charging current of the conductor pattern is suppressed.

Further, since the base material of the printed wiring board is rectangular and the conductor portions are separated such that the separated portions of the conductor pattern are arranged in the longitudinal direction of the base material, The effect of suppressing radiated noise is greatly improved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a printed wiring board according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a printed wiring board according to a second embodiment of the present invention.

FIG. 3 is a diagram illustrating a printed wiring board according to a third embodiment of the present invention.

FIG. 4 is a diagram for describing a printed wiring board according to a third embodiment of the present invention.

FIG. 5 is a diagram for explaining a printed wiring board according to a fourth embodiment of the present invention.

FIG. 6 is a view for explaining a printed wiring board according to a fourth embodiment of the present invention.

[Explanation of symbols]

1, 11, 21, 31 Base materials 2a, 2b, 12a, 12b, 22a, 22b, 32
a, 32b Conductor pattern 3, 8, 13, 18, 23, 28, 33, 38 Via hole 4, 14, 24, 34 Chip-type resistor 5a, 5b, 25a, 25b Signal wiring 16a, 16b, 16c, 36a, 36b, 36c
IC 17a, 17b, 37a, 37b Clock signal line 29a, 29b, 39a, 39b Inner layer solid pattern 30a, 30b, 40a, 40b, 40c, 40d, 4d
0e, 40f Separation part 41a, 41b Via hole clearance 42a, 42b, 42c, 42d Connection part

Claims (34)

[Claims] In a printed wiring board including a plate-shaped base material and a conductor pattern formed on the plate-shaped base material and used as a power supply pattern or a ground pattern, the conductor pattern is separated at a predetermined position. A printed wiring board, wherein separated portions of the conductor pattern are connected to each other via the circuit element with heat loss. 2. The clock signal line is formed on the plate-like base material, and the conductor pattern is separated at a portion of the conductor pattern other than a portion near the signal line. Printed wiring board. 3. The plate-like substrate has a rectangular shape,
The printed wiring board according to claim 1, wherein the conductive pattern is separated such that separated portions of the conductive pattern are arranged in a longitudinal direction of the plate-shaped base material. 4. The shape of the plate-shaped substrate is rectangular,
The printed wiring board according to claim 1, wherein the conductive pattern is separated such that separated portions of the conductive pattern are arranged in a direction perpendicular to a longitudinal direction of the plate-shaped base material. 5. The printed wiring board according to claim 1, wherein a resistor is used as the circuit element. 6. The printed wiring according to claim 5, wherein the resistor is formed at the predetermined location where the conductor pattern is separated, and a resistance value of the resistor varies according to the location of the predetermined location. Board. 7. The printed wiring board according to claim 5, wherein the resistance value of the resistor increases as the position of the resistor approaches the outer periphery of the plate-shaped substrate. 8. The printed wiring board according to claim 5, wherein the resistor is a lead type or a chip type. 9. The printed wiring board according to claim 5, wherein the resistor is formed by printing. 10. The printed wiring board according to claim 1, wherein a ferrite element is used as the circuit element. 11. The printed wiring according to claim 10, wherein the ferrite element is formed at the predetermined location where the conductor pattern is separated, and an inductance value of the ferrite element varies depending on the location of the predetermined location. Board. 12. The printed wiring board according to claim 10, wherein an inductance value of the ferrite element is larger as a position of the ferrite element is closer to an outer periphery of the plate-shaped base. 13. The printed wiring board according to claim 10, wherein the ferrite element is a lead type or a chip type. 14. One surface or an inner layer of the plate-like base material,
The printed wiring board according to any one of claims 1 to 13, wherein a plain pattern used for power supply or ground is formed, and the plain pattern is separated at a predetermined position. 15. A signal line for a clock passing near a separated portion of the plane pattern is formed on the plate-shaped substrate, and the separated portions of the plane pattern are connected to the plane. The printed wiring board according to claim 14, wherein the printed wiring board is electrically connected in the vicinity of the signal line by a connection portion made of the same material as the pattern. 16. The planar pattern is separated such that the shape of the plate-shaped substrate is rectangular, and the separated portions of the plane-shaped pattern are arranged in the longitudinal direction of the plate-shaped substrate. The printed wiring board according to claim 14 or 15, wherein 17. The plane-shaped base material such that the shape of the plate-shaped base material is rectangular, and separated portions of the plane-shaped pattern are arranged in a direction perpendicular to a longitudinal direction of the plate-shaped base material. 16. The printed wiring board according to claim 14, wherein the patterns are separated. 18. A method for designing a printed wiring board including a plate-shaped base material and a conductor pattern formed on the plate-shaped base material and used as a power supply pattern or a ground pattern, the method comprising: And a step of connecting the separated portions of the conductor pattern via a circuit element involving heat loss. 19. The method according to claim 19, further comprising the step of forming a signal line for a clock on the plate-shaped base material, wherein the conductor pattern is separated from a portion of the conductor pattern other than a portion near the signal line. 19. The method for designing a printed wiring board according to 18. 20. The plate-shaped base material is rectangular in shape, and the conductive pattern is separated such that separated portions of the conductive pattern are arranged in the longitudinal direction of the plate-shaped base material. Or a method for designing a printed wiring board according to item 19. 21. A shape of the plate-shaped base material is rectangular, and the conductive pattern is formed such that separated portions of the conductive pattern are arranged in a direction perpendicular to a longitudinal direction of the plate-shaped base material. The method for designing a printed wiring board according to claim 18, wherein the separation is performed. 22. The method for designing a printed wiring board according to claim 18, wherein a resistor is used as the circuit element. 23. The method according to claim 22, wherein the position where the resistor is formed is the predetermined location where the conductor pattern is separated, and the resistance value of the resistor varies depending on the location of the predetermined location. The printed wiring board design method described. 24. The resistance value of the resistor increases as the position of the resistor approaches the outer periphery of the plate-shaped substrate.
24. The method for designing a printed wiring board according to 2 or 23. 25. The method for designing a printed wiring board according to claim 22, wherein the resistor is a lead type or a chip type. 26. The method for designing a printed wiring board according to claim 22, wherein the resistor is formed by printing. 27. The method for designing a printed wiring board according to claim 18, wherein a ferrite element is used as the circuit element. 28. The ferrite element according to claim 27, wherein the position where the ferrite element is formed is the predetermined location where the conductor pattern is separated, and an inductance value of the ferrite element varies depending on the location of the predetermined location. The printed wiring board design method described. 29. The printed wiring board design method according to claim 27, wherein the inductance value of the ferrite element is larger as the position of the ferrite element is closer to the outer periphery of the plate-shaped base material. 30. The method for designing a printed wiring board according to claim 27, wherein the ferrite element is a lead type or a chip type. 31. One surface or an inner layer of the plate-like base material,
4. The method according to claim 1, further comprising: forming a plane pattern used for power supply or ground; and separating the plane pattern at a predetermined position.
0. The method for designing a printed wiring board according to any one of 0 to 0. 32. A step of forming, on the plate-like base material, a clock signal line passing near a separated portion of the plane pattern, and separating the separated portions of the plane pattern from each other. 32. The method of designing a printed wiring board according to claim 31, further comprising a step of electrically connecting near the signal line by a connection portion made of the same material as the plane pattern. 33. The planar pattern is separated such that the shape of the plate-shaped substrate is rectangular, and the separated portions of the plane-shaped pattern are arranged in the longitudinal direction of the plate-shaped substrate. Item 34. The method for designing a printed wiring board according to Item 31 or 32. 34. The plane-shaped base material such that the shape of the plate-shaped base material is rectangular, and the separated portions of the plane-shaped pattern are arranged in a direction perpendicular to the longitudinal direction of the plate-shaped base material. The method for designing a printed wiring board according to claim 31, wherein the pattern is separated.