JPH01198100A - Printed wiring substrate - Google Patents

Abstract

PURPOSE:To define a loop of a magnetic core around wirings on a printed wiring substrate and to decrease noises, by providing openings near predetermined circuit patterns and arranging the magnetic core through these openings so as to define a closed magnetic circuit around the wirings of said predetermined wiring patterns. CONSTITUTION:A printed wiring substrate 1 has wiring patterns 2 thereon. Rectangular holes 3a, 3b are formed near the opposite sides of these circuit patterns 2, respectively. A ferrite core 4 is arranged through the holes 3a, 3b so as to form a loop around the wiring patterns 2. The ferrite core 3 is received in a molded case 7 and fixed to the printed wiring substrate 1 by means of screws 5 and nuts 6. If wiring in a predetermined wiring pattern region is passed through the loop of the magnetic core once or twice or more and a connection switching means is provided in a part of the wiring, the connection switching means can control whether and how many times the wiring is passed through the magnetic core loop.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a printed wiring board, and particularly to a printed wiring board in which a magnetic core is disposed on the board to reduce noise.

[Conventional weight] In recent years, standards regarding the noise generated by electronic devices have become increasingly strict, but it is said that the magnitude of the noise generated by electronic devices varies depending on the parts used, etc., and cannot be known unless it is actually measured. The current situation is that the countermeasures are often a process of trial and error.

Conventionally, when taking measures against noise on a printed wiring board, one end of the wire 15 is connected to the wiring pattern 2a, as shown in Fig. 1θ. ll, and the other end of the wire 15 is attached to the ferrite core 1.
This was done by soldering to the wiring pattern 2b after passing through the wiring pattern 6.

[Problem 1 to be Solved by the Invention] 2 In the conventional printed wiring board, the wire 15 is soldered to the wiring pattern 2a as described above.

Pass this wire 15 through the ferrite core 16 and further distribute the V
A Because half 111 was attached to pattern 2b, there was a
The set S7 required one number.

In particular, as the number of wires that require noise countermeasures increases, the number of wire rods 15 increases, and depending on the amount of noise, the number of turns in which the wire rods 15 are wound around the ferrite core 16 must be increased. However, there was a problem in that it required more assembly man-hours.

[Means for Solving the Problems] The printed wiring board of the present invention has an opening in the vicinity of a predetermined wiring pattern, and forms a closed magnetic circuit around the wiring of the predetermined wiring pattern through the opening. It is characterized by a magnetic core arranged so as to

[Function] The printed wiring board of the present invention has an opening in the vicinity of a predetermined wiring pattern, and a magnetic core is arranged so as to form a closed magnetic circuit around the wiring of the predetermined wiring pattern through the opening. By installing a magnetic core, a loop formed by the magnetic core is formed around the wiring on the printed wiring board to prevent noise.

Note that the wiring in the predetermined wiring pattern area is passed through the loop of the magnetic core once or twice or more.

By providing a connection switching stage F in a part of the wiring and using the connection switching means to switch whether or not the wire passes through the loop of the magnetic core or the number of times the wire passes through the loop, it is possible to avoid complicated wiring without changing the arrangement of the magnetic core. Whether or not the wire passes through the loop of the magnetic core or the number of times the wire passes can be changed by the connection switching means without performing any work.

[Example] Below, this ffil! Eleventh embodiment will be explained in detail using the drawings.

In addition, in each of the following embodiments, the same constituent members are given the same reference numerals.

FIG. 1 is a plan view of a magnetic core arrangement portion of a first embodiment of a printed wiring board according to the present invention.

FIG. 2 is a sectional view taken along the line AA' of the magnetic core arrangement section 1-.

As shown in both figures, print distribution! A wiring pattern 2 is formed on the a-substrate l, and square holes 3a and 3b are provided near both sides of the wiring pattern 2. The ferrite core 4 is arranged on the printed wiring board 1 so as to form a loop around the wiring pattern 72 through the holes 3a and 3b. The ferrite core 4 is placed in a molded case 7, and this molded case 7 is attached to the printed wiring board 1 with screws 5 and nuts 6, and printed circuit board 1 is installed! I
a Fixed to the substrate 1.

In the printed wiring board of this example, the ferrite core can be easily attached to the printed wiring board l using only screws and nuts, so installation during assembly is easy.
It is also easy to remove. As a result, the noise prevention effect can be easily confirmed by attaching and detaching the ferrite core, and even if the ferrite core is no longer necessary due to other noise countermeasure calculations, it can be removed without the need for complicated removal work such as soldering. be able to.

FIG. 3 is a plan view of the magnetic core arrangement portion of the second embodiment of the printed wiring board of the present invention.

As shown in FIG. 3, the printed wiring board of this embodiment has part of the wiring 2a passed through the loop of the ferrite core 4 and connected to the wiring 2b via the jumper wire 8a (solid line in the figure). , the wiring 2b is arranged to pass through the loop of the ferrite core 4. That is, the wiring 2a, 2b on the printed wiring board l and the jumper fj 8
A constitutes a structure in which a signal line is wound once around a ferrite core 4.

With this configuration, the number of times the wiring 2a passes through the loop of the ferrite core can be increased, and the noise countermeasures of the first embodiment can be further strengthened.

In this embodiment, if a jumper wire is used as a connection switching means and the connection is switched from the jumper wire 8a (solid line in the figure) to the jumper wire 8b (broken line in the figure), the wiring can be connected to the ferrite core 4 twice. The wiring pattern that runs through the ferrite core can be switched to a wiring pattern that runs the wire through the ferrite core once. Conversely, it is also possible to switch the wiring pattern in which the wiring passes through the ferrite core 4 twice to a wiring pattern in which the wiring passes through the ferrite core twice.

That is, by switching the jumper wires, it is possible to easily switch the number of times the wiring passes through the loop of the ferrite core 4 depending on the need for noise countermeasures.

FIG. 4 is a plan view of the magnetic core arrangement portion of the third embodiment of the printed wiring board of the present invention.

The printed wiring board of this embodiment uses a double-sided board 1a as a printed wiring board, and as shown in FIG. After passing through the loop, connect it to the wiring 2c on the back side of the board through the through hole, and connect the wiring 2c to the wiring 2c on the back side of the board.
is connected to the wiring 2b on the surface through a through hole.

The wiring 2b is arranged so as to pass through the loop of the ferrite core 4 again.

Unlike the second embodiment, this embodiment does not use jumper wires, so it can be mounted at high density, and is preferably used, for example, when there are many signal lines that require noise countermeasures. .

FIG. 5 is a plan view of the magnetic core arrangement portion of the fourth embodiment of the printed wiring board of the present invention.

In this embodiment, as shown in FIG. 5, the wiring pattern is placed at the end of the printed wiring board I, and one hole is made in the printed wiring board I.

This embodiment has the advantage that the printed wiring board can be used more effectively than the first embodiment because only one hole is formed, and the work can be simplified.

FIG. 6(A) is a plan view of the magnetic core arrangement portion of the fth embodiment of the printed wiring board of the present invention.

FIG. 6(B) is a perspective view of the connector connection section.

In FIGS. 6(A) and 6(B), the connector 9a.

9b is a connector for connecting to other units or parts. Conventionally, when noise countermeasures were taken at such a connector connection part, a ferrite core was attached to the wire bundle 10. In this case, the installation work is complicated,
In particular, when winding the east wire 10 around the ferrite core multiple times, there was a problem in that the efficiency was very low.

In this embodiment, as shown in FIG. 6(A), the connector 9a
A ferrite core 4 is arranged on a printed wiring board near the same as in the second embodiment. With such a configuration, the east line l
It is no longer necessary to pass the ferrite core 4 through O,
This embodiment, in which the ferrite core 4 is provided on the printed wiring board 1 side, is more effective than the conventional method of attaching the ferrite core to the bundled wire 10, because manufacturing is easier and the noise countermeasure is more effective when it is closer to the noise source. Has a noise reduction effect. Furthermore, when attaching a ferrite core to the east line 1O, it was impossible to determine the exact position to attach the ferrite core, but in this embodiment, the position can be fixed accurately.

Furthermore, when attaching a ferrite core to the east line, it was necessary to fix the ferrite core to the main body to prevent vibrations, but this is no longer necessary in this embodiment.

FIG. 7 is a sectional view of the magnetic core arrangement portion of the sixth embodiment of the printed wiring board of the present invention.

In this embodiment, as shown in FIG. 7, a buffer member 12 is inserted between a printed wiring board l and a ferrite core 4, and the ferrite core 4 is tightened with a binding member 11 to be fixed to the printed wiring board l. It is.

In this embodiment, compared to the first embodiment, the area of the screw fixing portion is unnecessary, and the printed wiring board 1 can be used effectively.

FIG. 8 is a sectional view of the magnetic core arrangement portion of the seventh embodiment of the printed circuit board of the present invention.

In this embodiment, as shown in FIG. 8, the ferrite core 4 consists of a flat plate part 4a and a U-shaped part 4b, and the flat plate part 4a is printed and bonded using an adhesive member 14. It is attached to the printed circuit board 1, and then the U-shaped portion is tightened with a binding member 13 to be fixed to the printed circuit board 1.

In this embodiment, the area of the screw fixing part is not required, and the printed wiring board can be used effectively, and the automation of the arrangement of the ferrite core 4 is 100 million times, so that the manufacturing cost can be reduced.

FIG. 9 is a sectional view of the magnetic core arrangement portion of the eighth embodiment of the printed wiring board of the present invention.

In the seventh embodiment, when the flat plate portion 4a of the ferrite core 4 deviates from the U-shaped portion 4b (the ninth embodiment
There is a problem in that the contact area between the flat plate portion 4a and the U-shaped portion 4b changes in the X direction in the figure, and the characteristics of the ferrite core 4 change.

In this embodiment, as shown in FIG. 9, the size of the flat plate portion 4a of the ferrite core 4 of the seventh embodiment is changed to the U-shaped portion 4b
Even if the flat plate part 4a is displaced from the U-shaped part 4b, the contact area between the flat plate part 4a and the U-shaped part 4b does not change, and the characteristics are stabilized. can be done.

[Effects of the Invention] As explained in detail above, according to the printed wiring board of the present invention, an opening is provided near a predetermined wiring pattern,
By arranging the magnetic core so as to form a closed magnetic circuit around the wiring in the predetermined wiring pattern area through this opening, the magnetic core is fixed around the wiring in the printed wiring (board 1-). This makes it possible to install the noise filter on a printed wiring board.

The printed wiring board of the present invention has a feature that the printed wiring board can be formed without increasing the number of work steps, especially when wiring is passed through the magnetic core multiple times.

Note that the wiring in the predetermined wiring pattern area is passed through the loop of the magnetic core once or twice or more, a connection switching means is provided in a part of the wiring, and the connection switching means is used to switch the wiring within the loop of the magnetic core. By switching the presence or absence of passage or the number of passages, the wiring can be easily passed through the loop of the magnetic core according to the need for noise countermeasures using the connection switching means without changing the arrangement of the magnetic core or performing complicated wiring work. It becomes possible to switch whether or not to pass or the number of passes.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a magnetic core arrangement portion of a first embodiment of the printed wiring board of the present invention. FIG. 2 is a sectional view of the magnetic core arrangement section. FIG. 3 is a plan view of the magnetic core arrangement portion of the second embodiment of the printed wiring board of the present invention. FIG. 4 is a plan view of the magnetic core arrangement portion of the third embodiment of the printed wiring board of the present invention. FIG. 5 is a Y-plane view of the magnetic core arrangement portion of the fourth embodiment of the printed wiring board of the present invention. FIG. 6 is a plan view of the magnetic core arrangement portion of the fifth embodiment of the printed wiring board of the present invention. FIG. 7 is a sectional view of the magnetic core arrangement portion of the sixth embodiment of the printed wiring board of the present invention. FIG. 8 is a sectional view of the magnetic core arrangement portion of the seventh embodiment of the printed wiring board of the present invention. FIG. 9 is a sectional view of the magnetic core arrangement portion of the eighth embodiment of the printed wiring board of the present invention. FIG. 10 is a top view of a magnetic core arrangement portion of a conventional printed wiring board. l Niblint wiring board, 2: wiring pattern. 3a, 3b: hole, 4: ferrite core, 5: screw, 6:
Nut, 7: Mold case, 8a, 8b: Jumper wire, 9a, 9b: Connector, IO22 wire 11.13: Binding member, 12: Buffer member, 14: Adhesive member. Agent JR Riju Yamashita Jo Taira Figure 1 Figure 2 Figure 6 Figure 7 b

Claims (2)

[Claims] (1) A printed wiring board in which an opening is provided near a predetermined wiring pattern, and a magnetic core is arranged so as to form a closed magnetic circuit around the wiring of the predetermined wiring pattern through the opening. (2) Passing the predetermined wiring pattern through the loop of the magnetic core once or twice or more, providing a connection switching means in a part of the wiring, and passing the wiring within the loop of the magnetic core by the connection switching means. 2. The printed wiring board according to claim 1, wherein the presence or absence of or the number of times of passing is switched.