JP2000059168A - Laminated type lc noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated type LC noise filter capable of being miniaturized without damaging noise elimination performance. SOLUTION: For this noise filter, a first coil 1 is disposed on one end of a lamination body 4, a second coil 2 is disposed on the other end of the lamination body 4, and a ground side capacitor electrode 15 and a hot side capacitor electrode 16 for constituting a capacitor 3 are disposed between the first coil 1 and the second coil 2. A non-electrode part 15a is provided in the disposing area of the ground side capacitor electrode 15, and the tip part 1b of the first coil 1 is connected to the hot side capacitor electrode 16 and the tip part 2b of the second coil 2 through a line (via hole) 17 passing through the non- electrode part 15a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LC noise filter, and more particularly, to a multilayer LC noise filter.

[0002]

2. Description of the Related Art A laminated LC in which a coil element and a capacitor element are disposed in a ceramic by laminating a ceramic green sheet on which a coil pattern and a capacitor electrode pattern are formed on one of the LC noise filters. There is a noise filter.

[0006] As this laminated type LC noise filter, for example, as shown in FIGS. 6A and 6B, two coils of a first coil 51 and a second coil 52 and a hot-side capacitor electrode 63 are provided. And an element 54 in which a capacitor 53 including a ground-side capacitor electrode 65 is disposed.
A first external electrode 55a that is electrically connected to a base end (IN side end) 51a of the first coil 51, and a base end (O
A second external electrode 55b conducting to the UT side end) 52a;
There is a so-called T-type LC noise filter including a ground-side capacitor electrode 65 and a ground external electrode 56 which is conductive.

As shown in FIG. 7, this T-type LC noise filter has a plurality of ceramic green sheets 62 on which a coil pattern 61 constituting a first coil 51 is disposed.
A ceramic green sheet 64 on which a hot-side capacitor electrode 63 forming a capacitor 53 is disposed; a ceramic green sheet 66 on which a ground-side capacitor electrode 65 to be grounded is disposed; and a coil forming a second coil 52 After laminating a plurality of ceramic green sheets 68 on which the patterns 67 are disposed and upper and lower outer sheets (not shown), by pressing and firing, the external electrodes 55a, 55b
(FIG. 6).

[0005]

However, in the above-mentioned conventional laminated LC noise filter, as shown in FIG. 6, the coil pattern 61 constituting the first coil 51 is formed by the OUT-side end 52a of the second coil 52. (Proximal portion) 6 reaching a position near the second external electrode 55b connected to the second external electrode 55b
1a and the coil pattern 67 constituting the second coil 52
Is located near the first external electrode 55a connected to the IN-side end 51a of the first coil 51 (proximal portion)
Since the size of the product is reduced due to the presence of the external electrode 55b, the distance between the adjacent portion 61a of the coil pattern 61 and the external electrode 55b and the external portion 55a of the coil pattern 67 are reduced.
The interval of b becomes small, and the stray capacitance C between them becomes large. Then, for example, as shown in FIG. 8, the first coil 51 (specifically, the proximity portion 61a of the coil pattern 61 constituting the first coil 51) and the second external electrode 55b
When the capacitance C is formed between the first external electrodes 55a
Before the noise coming from
There is a problem in that the noise flows to the second external electrode 55b on the output side and noise cannot be sufficiently removed.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a laminated LC noise filter which can be reduced in size without impairing the noise removing performance.

[0007]

To achieve the above object, a laminated LC noise filter according to the present invention (claim 1) is a laminated LC noise filter in which a first inductance, a second inductance and a capacitor are connected in a T-shape. In the type LC noise filter, a first inductance coil (first coil) is provided from one end side, and a second inductance coil (second coil) is provided near the other end side; A laminate in which a ground-side capacitor electrode and a hot-side capacitor electrode constituting a capacitor are provided between the coil and the second coil; and one end of the laminate is electrically connected to a base end of the first coil. And a second external electrode disposed on the other end side of the laminate so as to be electrically connected to a base end of the second coil, and the ground-side capacitor electrode. And a tip end of the first coil is connected to the hot side capacitor electrode without being connected to the ground side capacitor electrode, and further connected to a tip end of the second coil. It is characterized by being.

A first coil is provided at one end of the laminated body, a second coil is provided at the other end of the laminated body, and a ground side constituting a capacitor is provided between the first coil and the second coil. By providing the capacitor electrode and the hot-side capacitor electrode, a sufficient distance is provided between the input side inductance coil (eg, the first coil) and the output side external electrode (eg, the second external electrode). , And the generation of stray capacitance can be suppressed or prevented, and the performance as a noise filter can be improved.

Further, in the laminated LC noise filter according to the second aspect, a portion where no electrode is formed (electrode-free portion) is provided in a region where the ground-side capacitor electrode is provided,
The tip of the first coil is connected to the hot-side capacitor electrode via a line passing through the electrodeless portion,
Furthermore, it is characterized in that it is connected to the tip of the second coil.

An electrodeless portion is provided in a region where the ground-side capacitor electrode is provided, and a first electrode is provided through a line passing through the electrodeless portion.
When the tip of the coil is connected to the tip of the hot-side capacitor electrode and the tip of the second coil, the tip of the first coil is connected to the ground-side capacitor electrode without requiring a large wiring space. Therefore, it is possible to reliably connect to the hot-side capacitor electrode and the tip of the second coil, and it is possible to reduce the size of the product while ensuring the performance.

Further, in the laminated LC noise filter according to a third aspect of the present invention, at least one of the ground-side capacitor electrode and the hot-side capacitor electrode, and the first coil or the second coil.
At least one of the coil patterns constituting the coil,
It is characterized by being arranged on the same surface in the laminate.

The configuration in which the ground-side capacitor electrode or the hot-side capacitor electrode and the coil pattern constituting the first coil or the second coil are arranged on the same surface in the laminate reduces the number of laminates and reduces the size. It is possible to simultaneously form the ground-side capacitor electrode or the hot-side capacitor electrode and the coil pattern, thereby simplifying the manufacturing process and reducing the cost.

Further, in the laminated LC noise filter according to a fourth aspect, the coil pattern constituting the first coil or the second coil is formed on a surface of the laminated body on which the ground-side capacitor electrode is provided. It is characterized in that it is arranged at a position close to the earth-side capacitor electrode.

By arranging a coil pattern constituting the first coil or the second coil on a surface on which the earth-side capacitor electrode is provided, at a position close to the earth-side capacitor electrode, the coil pattern and the earth-side capacitor can be formed. It becomes possible to form a local LC filter structure by causing a capacitor coupling between the electrode and the electrode, and it is possible to further improve the noise removal performance.

In the laminated LC noise filter according to a fifth aspect, when the hot-side capacitor electrode is viewed from the laminating direction, a part thereof enters the inside of the coil loop of the first coil and the second coil. It is characterized by being formed in such a pattern.

A part of the hot-side capacitor electrode is
By forming a pattern so as to enter the inside of the coil loop of the first coil and the second coil, it is possible to adjust the degree of entry of the hot-side capacitor electrode into the coil loop and change the state of magnetic flux. That is, the filter characteristics can be controlled.

According to a sixth aspect of the present invention, in the laminated LC noise filter, the ground-side capacitor electrode is formed of two electrodes, a first ground electrode and a second ground electrode, which are separately provided. Features.

When the earth-side capacitor electrode is divided into a first earth electrode and a second earth electrode, the inductance characteristic can be changed according to the state of division, and the filter characteristic can be adjusted. Will be able to

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described, and features thereof will be described in more detail.

[Embodiment 1] FIG. 1A is a sectional view showing a laminated LC noise filter according to an embodiment of the present invention.
FIG. 1B is a perspective view showing the external configuration, and FIG. 2 is a diagram schematically showing the laminated LC noise filter of this embodiment for easy understanding.

As shown in FIG. 1 and FIG.
In the C noise filter, a first inductance coil (first coil) 1 is disposed at a position from one end in a laminated body (chip) 4 made of a dielectric ceramic, and is arranged from the other end of the laminated body 4. A second inductance coil (second coil) 2 is disposed at a position, and a ground-side capacitor electrode 1 is provided between the first coil 1 and the second coil 2.
5 and a capacitor 3 including a hot-side capacitor electrode 16 are provided.

Further, a first external electrode 5a is provided on one end side of the laminated body 4 and is electrically connected to the base end 1a of the first coil 1. On the other end side, a base end of the second coil 2 is provided. A second external electrode 5b that conducts with the ground electrode 2a is provided, and a ground external electrode 6 that conducts with the ground-side capacitor electrode 15 is disposed at the center of the side surface of the laminate.

In this laminated type LC noise filter, the tip 1b of the first coil 1 is provided in the area where the ground-side capacitor electrode 15 is provided, where the electrode is not formed (electrodeless part). A hot-side capacitor electrode 16 is connected via a line (via hole) 17 penetrating
And further connected to the tip 2 b of the second coil 2. The multilayer LC noise filter of this embodiment has the same circuit configuration as the conventional T-type LC noise filter shown in FIG.

Next, a method of manufacturing the laminated LC noise filter of this embodiment will be described with reference to FIGS. 3 (a) and 3 (b). This laminated LC noise filter is shown in FIG.
As shown in (b) (see FIGS. 1 and 2), the first coil 1
Alternatively, the ceramic green sheets 22a and 22b on which the coil patterns 21 constituting the second coil 2 are disposed, and the earth-side capacitor electrode 15 constituting the capacitor 3 are formed, and the first and second coils are constituted. A ceramic green sheet 23 in which the coil pattern 21 is located at a position close to the ground-side capacitor electrode 15, and a ceramic green sheet in which the hot-side capacitor electrode 16 and the coil pattern 21 constituting the capacitor 3 are disposed 24 and the upper and lower outer layer sheets (not shown) are laminated and pressed in such a manner that the ceramic green sheets 23 and the ceramic green sheets 24 are alternately laminated, thereby connecting the coil patterns and the electrodes via the via holes. I do.

Then, after the pressed body is fired under predetermined conditions, a conductive paste for forming an external electrode is applied and baked to form external electrodes 5a and 5b (FIG. 1). Thus, a laminated LC noise filter as shown in FIG. 1 is obtained.

In the laminated LC noise filter configured as described above, the first coil 1 is disposed at one end of the laminated body 4, and the second coil 2 is disposed at the other end of the laminated body 4. In addition, since the ground-side capacitor electrode 15 and the hot-side capacitor electrode 16 constituting the capacitor 3 are disposed between the first coil 1 and the second coil 2, an inductance coil (for example, First
It is possible to secure a sufficient distance between the coil 1) and an external electrode on the output side (for example, the second external electrode 5b), thereby suppressing and preventing the generation of stray capacitance, and as a noise filter. Performance can be improved.

A non-electrode portion 15a is provided in a region where the ground-side capacitor electrode 15 is provided, and the tip 1b of the first coil 1 is connected to the hot-side capacitor electrode through a via hole 17 penetrating the non-electrode portion 15a. 16 and the second coil 2
Is connected to the tip 2b of the first coil 1 without requiring a large wiring space.
Can be reliably connected to the hot-side capacitor electrode 16 and the tip 2b of the second coil 2 without conducting to the ground-side capacitor electrode 15, and the product can be downsized while ensuring performance. be able to.

On the surface on which the ground-side capacitor electrode 15 is provided, the coil pattern 21 forming the first coil 1 and the second coil 2 is provided at a position close to the ground-side capacitor electrode 15. Therefore, it is possible to form a local LC filter structure by causing a capacitor coupling between the coil pattern 21 and the ground-side capacitor electrode 15, and it is possible to further improve noise removal performance.

[Embodiment 2] FIG. 4 is a diagram showing a configuration of a main part of a laminated LC noise filter according to another embodiment of the present invention. In the laminated LC noise filter according to the second embodiment, when the hot-side capacitor electrode 16 is viewed from the laminating direction, both ends 16 a and 16 b are located inside the coil loop of the first coil 1 and the second coil 2. It is formed in a pattern that penetrates. Other configurations are
This is the same as the multilayer LC noise filter of the first embodiment, and in order to avoid duplication, the corresponding parts of the description of the first embodiment will be referred to and the description will be omitted. In FIG. 4,
1 to 3 denote the same or corresponding parts.

In the multilayer LC noise filter of the second embodiment, the end 16 of the hot-side capacitor electrode 16
Since a and 16b enter the inside of the coil loop of the first coil 1 and the second coil 2, the state of the magnetic flux is changed by adjusting the degree of entry of the hot-side capacitor electrode into the coil loop. And the filter characteristics can be controlled.

[Embodiment 3] FIG. 5 is a view showing a pattern of a ground-side capacitor electrode of a multilayer LC noise filter according to still another embodiment of the present invention. In the multilayer LC noise filter according to the third embodiment, as shown in FIG. 5, the ground-side capacitor electrode 15 is formed by the first ground electrode 18 and the second ground electrode 19 which are separately provided. Have been. A via hole 17 is formed between the first ground electrode 18 and the second ground electrode 19. The other configuration is the same as that of the laminated LC noise filter of the first embodiment. To avoid duplication, the corresponding parts of the description of the first embodiment will be referred to and the description will be omitted. Note that, in FIG. 5, portions denoted by the same reference numerals as those in FIG. 3 indicate the same or corresponding portions.

As in the third embodiment, the ground-side capacitor electrode 15 is divided into the first ground electrode 18 and the second ground electrode 19 to change the inductance characteristic of the capacitor according to the state of division. And the filter characteristics can be adjusted.

The present invention is not limited to the above embodiment, but relates to the specific shape, coil pattern, number of layers, etc. of the earth-side capacitor electrode and the hot-side capacitor electrode constituting the capacitor. Within the range, various applications and modifications can be made.

[0034]

As described above, in the laminated LC noise filter according to the present invention (claim 1), the first coil is disposed at one end of the laminate, and the second coil is disposed at the other end of the laminate. In addition to the arrangement, the ground-side capacitor electrode and the hot-side capacitor electrode constituting the capacitor are arranged between the first coil and the second coil. Coil) and an external electrode (for example, a second external electrode) on the output side, it is possible to secure a sufficient distance, to suppress and prevent the generation of stray capacitance, and to perform as a noise filter. Can be improved.

Further, like the laminated LC noise filter according to the second aspect, an electrodeless portion is provided in a region where the ground-side capacitor electrode is provided, and the first electrode is provided through a line penetrating the electrodeless portion.
When the tip of the coil is connected to the tip of the hot-side capacitor electrode and the tip of the second coil, the tip of the first coil is connected to the ground-side capacitor electrode without requiring a large wiring space. Therefore, it is possible to reliably connect to the hot-side capacitor electrode and the tip of the second coil, and it is possible to reduce the size of the product while ensuring performance.

Also, as in the laminated LC noise filter according to the third aspect, the ground side capacitor electrode or the hot side capacitor electrode and the coil pattern constituting the first coil or the second coil are arranged on the same surface in the laminate. With this configuration, the number of layers can be reduced to reduce the size of the product, and the ground-side capacitor electrode or hot-side capacitor electrode and the coil pattern can be formed at the same time. The process can be simplified and cost can be reduced.

Further, as in the laminated type LC noise filter according to the fourth aspect, the coil pattern constituting the first coil or the second coil is arranged close to the ground-side capacitor electrode on the surface on which the ground-side capacitor electrode is provided. If it is arranged at a position where it is set, it is possible to form a local LC filter structure by generating a capacitor coupling between the coil pattern and the earth side capacitor electrode, further improving the noise removal performance Can be done.

Further, like the laminated LC noise filter of the fifth aspect, the hot-side capacitor electrode is partially
When the pattern is such that it enters the inside of the coil loop of the first coil and the second coil, the degree of entry of the hot-side capacitor electrode into the coil loop can be adjusted to change the state of magnetic flux, The filter characteristics can be controlled.

Further, when the earth-side capacitor electrode is divided into a first earth electrode and a second earth electrode as in the laminated LC noise filter of the sixth aspect, the inductance characteristic is changed according to the state of division. This makes it possible to adjust the filter characteristics.

[Brief description of the drawings]

FIG. 1 (a) is a laminated LC according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a noise filter, and FIG. 2B is a perspective view illustrating an external configuration thereof.

FIG. 2 is a diagram schematically illustrating a laminated LC noise filter according to an embodiment of the present invention.

FIG. 3 (a) is a laminated LC according to an embodiment of the present invention.
It is a figure explaining the manufacturing method of a noise filter, and (b) is a figure which expands and shows a principal part.

FIG. 4 is a diagram illustrating a laminated type L according to another embodiment of the present invention.
It is a figure showing composition of an important section of a C noise filter.

FIG. 5 is a view showing a laminated type L according to still another embodiment of the present invention.
It is a figure showing the pattern of the earth side capacitor electrode of C noise filter.

6A is a cross-sectional view illustrating a conventional laminated LC noise filter, and FIG. 6B is a diagram illustrating a circuit configuration thereof.

FIG. 7 is a view illustrating a method of manufacturing a conventional laminated LC noise filter.

FIG. 8 is a diagram showing a state in which stray capacitance has occurred in a conventional laminated LC noise filter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st coil 1a 1st end of 1st coil 1b 1st end of 1st coil 2 2nd coil 2a 2nd end of 2nd coil 2nd end of 3rd coil 3 Capacitor 4 Lamination (chip) 5a 1st outside Electrode 5b Second external electrode 6 External electrode for ground 15 Earth side capacitor electrode 15a Electrodeless part 16 Hot side capacitor electrode 16a, 16b End of hot side capacitor electrode 17 Via hole 18 First earth electrode 19 Second earth electrode 21 Coil pattern 22a, 22b, 23, 24 Ceramic green sheet

Continued on the front page F term (reference) 5E070 AA05 AB01 CB13 CB17 CB20 DB08 EA01 5E082 AA01 AB03 BB02 BC39 DD08 FF05 FG06 FG48 FG54 GG10 MM24 5J024 AA01 BA03 DA04 DA28 DA31 DA32 DA35 EA08

Claims (6)

[Claims] 1. A laminated LC noise filter in which a first inductance, a second inductance, and a capacitor are connected in a T-shape, wherein a first inductance coil (first coil) is provided from one end side, and An inductance coil (second coil) is disposed near the other end, and an earth-side capacitor electrode and a hot-side capacitor electrode constituting a capacitor are disposed between the first coil and the second coil. A stacked body; a first external electrode disposed on one end of the stacked body so as to be electrically connected to a base end of the first coil; and a second coil base mounted on the other end of the stacked body. A second external electrode disposed so as to be electrically connected to an end, and an earth external electrode electrically connected to the earth-side capacitor electrode, and a tip end of the first coil is connected to the earth-side electrode. Connected to the hot side capacitor electrode without connecting to the capacitor electrode,
Further, the laminated LC noise filter is connected to the tip of the second coil. 2. An area where no electrode is formed (electrode-free portion) is provided in a region where the ground-side capacitor electrode is provided, and the first electrode is provided via a line penetrating the electrode-free portion.
The laminated LC noise filter according to claim 1, wherein a tip of the coil is connected to the hot-side capacitor electrode, and further connected to a tip of the second coil. 3. At least one of the ground-side capacitor electrode and the hot-side capacitor electrode and at least one of coil patterns constituting the first coil or the second coil are arranged on the same surface in the laminate. 3. The multilayer LC noise filter according to claim 1, wherein: 4. A coil pattern constituting the first coil or the second coil is disposed at a position close to the ground-side capacitor electrode on a surface of the laminate on which the ground-side capacitor electrode is disposed. The multilayer LC noise filter according to any one of claims 1 to 3, wherein: 5. The hot-side capacitor electrode is formed in a pattern such that a part thereof enters a coil loop of the first coil and the second coil when viewed from the laminating direction. The laminated LC noise filter according to any one of claims 1 to 4. 6. The device according to claim 1, wherein the ground-side capacitor electrode is formed of two electrodes, a first ground electrode and a second ground electrode, which are separately provided. 4. The laminated LC noise filter according to 1.