JPS6410964B2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a chip type noise removal filter.
More specifically, the present invention relates to a chip type noise removal filter in which two flat ferrite plates are provided with an inductance function and a case function.

(Prior art) Conventionally, as a noise removal filter, the first
As shown in the figure, cylindrical ferrite beads 2 and 3 are arranged coaxially on both sides of a disk-shaped capacitor 1 with a hole in the center, and these capacitor 1 and ferrite beads 2 and 3 are connected to each other. The through terminal 4 is passed through and the whole is housed inside a cylindrical metal case 5, and the electrodes 1a and 1b formed on the outer peripheral wall and the inner peripheral wall of the capacitor 1, respectively, are soldered to the metal case 5 and the through terminal 4, respectively. It is generally known that the metal case 5 is attached and the inside of the metal case 5 is filled with resin 6.

As shown in Fig. 2, the above-mentioned noise filter is as follows.
Ferrite beads 2 and 3 are placed in the middle of the through terminal 4.
and _between these inductances _{L 2 and} L ₃ ,
It has an equivalent circuit in which the feedthrough terminal 4 is connected to the ground via the capacitor 1, but since the noise filter shown in Figure 1 is a feedthrough type, it is difficult to attach the noise filter to the printed circuit board. The size is also large, making it difficult to package small, high-density electronic devices that require noise filters.

(Object of the invention) The present invention has been made in view of the above-mentioned circumstances regarding conventional noise filters, and its object is to
By incorporating a conductive path and a capacitor between two flat ferrite plates, the ferrite plate acts as an inductance for the conductive path and also functions as a case for a noise filter. The object of the present invention is to obtain an inexpensive chip-type noise removal filter that can be drawn out and mounted on a printed circuit board or the like.

(Structure of the Invention) Therefore, in the present invention, a conductive path made of a metal plate is arranged on one main surface of a flat ferrite plate,
A chip-shaped capacitor is connected between the middle of this conductive path and a ground electrode provided on the ferrite plate, and another ferrite plate is joined to the main surface of the ferrite plate, and both ends of the conductive path and the ground electrode are connected to each other. are drawn out to the outside of the two ferrite plates as an input terminal, an output terminal, and a ground terminal, respectively.

(Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings.

In FIGS. 3 and 4, 11 and 12 are ferrite plates, 13 is a conductive path, 14 is a chip capacitor, 15 is an input terminal, 16 is an output terminal, and 17 is a ground terminal.

The ferrite plates 11 and 12 are rectangular flat plates having substantially equal dimensions, and
Of the ferrite plates 11 and 12, one of the ferrite plates 11 has a concave portion 18 formed therein for insertion of a conductive path, as shown in FIG.
Both ends of the conductive path insertion recess 18 are located on one side of the main surface of the ferrite plate 11, and both ends and the middle part are wider than the other parts.

A ground electrode insertion recess 19 is also formed on the main surface of the ferrite plate 11 between both ends of the conductive path insertion recess 18 .

A conductive path 13, which is made by punching a metal plate made of copper or the like with good conductivity into a shape suitable for the conductive path insertion recess 18, is inserted into the conductive path insertion recess 18 as shown in FIG. An input terminal 15 and an output terminal 16, which are extensions of both ends of the channel 13, are bent onto one end surface and the other main surface of the ferrite plate 11, respectively.

Similarly, in the ground electrode insertion recess 19,
A plate-shaped ground electrode 17a is fitted, and a ground terminal 17, which is an extension of the ground electrode 17a, is bent onto one end surface and the other main surface of the ferrite plate 11.

Chip capacitors 14 are provided in the wide portion 13a and the ground electrode 17a at the intermediate portion of the conductive path 13, respectively.
electrodes 14a and 14b are soldered.

Another ferrite plate 12 having a recess (not shown) into which the chip capacitor 14 is inserted is bonded to the main surface of the ferrite plate 11 on the side where the conductive path 13 and the ground electrode 17a are formed using an adhesive or the like. has been done.

By doing as described above, as can be seen from FIG. 4, the input terminal 15 of the conductive path 13 can be
and this wide portion 13 of the conductive path 13
From a to the output terminal 16, the ferrite plates 11 and 12 have inductances L ₁₅ and L ₁₆
These inductances L ₁₅ and
As shown in FIG. 6, L ₁₆ is connected between the input terminal 15 and the wide portion 13a and between the output terminal 16 and the wide portion 13a, and is connected to the wide portion 13a and the ground terminal. A chip type noise removal filter in which the chip capacitor 14 is connected between the chip capacitor 17 and the chip capacitor 17 can be obtained.

In addition, in the above embodiment, the ferrite plate 11
The slits 11a and 12a formed in and 12 are for making the magnetic flux contributing to the inductances _L15 and _L16 as large as possible. That is, now inside the ferrite plates 11 and 12, as shown in FIG.
Assuming that magnetic fluxes 31 and 32 run around the conductive paths 13 and 13, of the magnetic flux 31 that runs around one of the conductive paths 13, the magnetic flux 31 that runs on the outermost side
A is a magnetic flux 32a that goes around the inside of the ferrite plates 11, 12 because of the slits 11a, 12a, and out of the magnetic flux 32 that runs around the other conductive path 13, a magnetic flux 32a that runs on the outermost side of the ferrite plates 11, 12.
Because of the slits 11a and 12a, the magnetic flux 3 also goes around inside the ferrite plates 11 and 12, and these magnetic fluxes 3
1a, 32a reach between the conductive paths 13, 13 and strengthen each other.
It will move around to the 13th side.

Even when the directions of the magnetic fluxes 31 and 32 are opposite to the above, the same relationship as above can be obtained.

Therefore, magnetic fluxes 31a and 32a are different from other magnetic fluxes 3
The inductance is not weakened by interference with the conductive paths 13 and 31, but acts on the conductive paths 13 and 13, increasing the inductance.

Furthermore, in the above embodiment, the input terminal 15, output terminal 16, and ground terminal 17 may be drawn out only to one end surface of the ferrite plate 11, as shown in FIG.

Next, other embodiments of the present invention are shown in FIGS. 9 and 10.
11 and 12.

The noise removal filter shown in FIG. 9 is different from the noise removal filter shown in FIGS. 3 and 4.
The input terminal 15 and the output terminal 16 are respectively drawn out to two opposing end faces which are different from the lead out end face of the ground terminal 17 of the ferrite plate 11.

Moreover, the noise removal filter shown in FIG.
Among the ferrite plates 11 and 12, ferrite plate 1
2 is provided with a hole 12b for accommodating the chip capacitor 14, and the conductive path 13 and the chip capacitor 14 located between the ferrite plate 12 and the ferrite plate 11 are provided.
The ground electrode 17a and the electrode 14a of the chip capacitor 14 are soldered together.

The noise removal filters described above in FIGS. 9 and 10 each have an equivalent circuit shown in FIG. 6.

On the other hand, the noise removal filter shown in FIG.
In the noise removal filter described in FIGS. 3 and 4, chip capacitors 24a and 24b are connected between each end of the conductive path 13 and the ground electrode 17a, as shown in FIG. An inductance L ₁₃ acting on the conductive path 13 by the ferrite plates 11 and 12 is connected between the input terminal 15 and the output terminal 16, and between the input terminal 15 and the ground terminal 17 and between the output terminal 16 and the ground. It has an equivalent circuit in which chip capacitors 24a and 24b are connected between terminal 17, respectively.

Moreover, the noise removal filter shown in FIG.
Among the chip capacitors 24a and 24b of the noise removal filter shown in FIG.
As shown in FIG. 14, the circuit has an equivalent circuit in which the chip capacitor 24a is removed from the equivalent circuit in FIG. 12.

It should be noted that the above-mentioned embodiments of the present invention are not intended to limit the present invention. In particular, the conductive paths and terminals shown in each embodiment may be in the form of a film instead of a plate, and their shapes may be arbitrary. Furthermore, the shape of the chip capacitor and its connection method are also arbitrary.

(Effects of the Invention) As is clear from the above detailed description, the present invention allows the ferrite plate to act as an inductance on the conductive path incorporated between the flat ferrite plates, and also functions as a case for a noise removal filter. This eliminates the need for a metal case like conventional noise removal filters, and it is a chip-type noise reduction that can be directly mounted on inexpensive printed circuit boards, etc., with a small number of parts and no processes such as resin filling. You can get a filter.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a conventional noise removal filter, FIG. 2 is an equivalent circuit diagram of the noise removal filter of FIG. 1, and FIG. 3 is a perspective view of an embodiment of the noise removal filter according to the present invention. Fig. 4 is an exploded perspective view of the noise removal filter shown in Fig. 3, Fig. 5 is a perspective view of the ferrite plate on the conductive path formation side of the noise removal filter shown in Fig. 3, and Fig. 6 is an exploded perspective view of the noise removal filter shown in Fig. 3. An equivalent circuit diagram, FIG. 7 is an explanatory diagram of the operating function of the ferrite plate, and FIGS. 8, 9, and 10 are perspective views of modifications of the noise removal filter shown in FIG. 3, respectively.
FIG. 11 and FIG. 12 are perspective views of other embodiments of the chip-type noise removal filter according to the present invention, respectively;
FIGS. 13 and 14 are equivalent circuit diagrams of the chip type noise removal filters shown in FIGS. 11 and 12, respectively. 11, 12... Ferrite plate, 13... Conductive path, 14... Chip capacitor, 14a, 14b
... Electrode, 15 ... Input terminal, 16 ... Output terminal, 17 ... Earth terminal, 17a ... Earth electrode.

Claims (1)

[Claims] 1. A conductive path made of a metal plate is arranged on one main surface of a flat ferrite plate, and a chip-shaped capacitor is connected between the conductive path and a ground electrode provided on the ferrite plate. Another ferrite plate is bonded to the main surface of the ferrite plate, and both ends of the conductive path and the ground electrode are drawn out to the outside of the two ferrite plates as an input terminal, an output terminal, and a ground terminal, respectively. Chip type noise removal filter.