JP3161455B2 - Common mode choke coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a common mode choke coil, and more particularly to a common mode choke coil used for removing common-mode noise in a high-frequency electronic circuit.

[0002]

2. Description of the Related Art As a conventional common mode choke coil, for example, as shown in FIG. 8, a laminated common mode choke coil 80 incorporating two coils is known. The laminated common mode choke coil 80 is composed of an insulating sheet 81 having coil conductors 82 to 85 and the like provided on the respective surfaces. Coil conductors 82 and 83
Are spirally connected electrically in series via via holes 87 provided in the insulating sheet 81, have a coil axis parallel to the stacking direction of the insulating sheets 81, and have a winding direction clockwise. The shape coil L1 is used. The coil conductors 84 and 85 are provided in the via holes 8 provided in the insulating sheet 81.
7 are electrically connected in series via the insulating sheet 81.
Having a coil axis parallel to the stacking direction of
The spiral coil L2 is wound in the clockwise direction.

[0003] After each insulating sheet 81 is stacked,
It is fired integrally to form a laminate 92 as shown in FIG. The input external electrodes 93a and 94 of the two coils L1 and L2 are provided on the front and rear side surfaces of the laminate 92, respectively.
a and output external electrodes 93b and 94b. One end of the coil L1 (specifically, the coil conductor 8
The second lead portion 82a) is electrically connected to the input external electrode 93a, and has the other end (the lead portion 83 of the coil conductor 83).
a) is electrically connected to the output external electrode 93b.
One end of the coil L2 (lead portion 8 of coil conductor 84)
4a) is electrically connected to the input external electrode 94a, and the other end (the lead portion 85a of the coil conductor 85) is electrically connected to the output external electrode 94b.

Here, the coil axes of the coils L1 and L2 and the input / output external electrodes 93a to 94b are perpendicular to the mounting surface 95 of the laminate 92 (in other words, the mounting surface of the choke coil 80). The coil axes of the coils L1 and L2 are parallel to the input / output external electrodes 93a to 94b. The common mode choke coil 80 has almost no influence on the normal mode signal, but acts as an inductance on the common mode signal (common mode noise).

[0005]

By the way, the conventional common mode choke coil 80 needs to be arranged so that the leading ends of the coils L1 and L2 do not overlap with each other in terms of structure. For this reason, the length of the pattern of the coil conductors 82 and 83 constituting the coil L1 is usually different from the length of the pattern of the coil conductors 84 and 85 constituting the coil L2.

Therefore, in the conventional common mode choke coil 80, the coil conductors 82 and 83 and the coil conductor 8
The impedance of the normal mode component of the coil L1 matches the impedance of the normal mode component of the coil L2 by making the pattern shapes of 4, 85 different. However, the coil conductor 8
The impedance difference of the normal mode component due to the difference between the shape of the coil conductors 2 and 83 and the shape of the coil conductors 84 and 85 will inevitably occur. Thereby, when a normal mode signal flows through each of the coils L1 and L2,
Magnetic fluxes acting on the coils L1 and L2 so as to cancel each other out are not generated substantially equally, and there is a problem that the normal mode signal is distorted.

When the pattern shapes of the coil conductors 82 and 83 and the pattern shapes of the coil conductors 84 and 85 are made different in order to match the impedance of the normal mode component, the coil conductors 82 to 83 constituting the coil L1 and the coil L2 are different. There is a problem that the number of types of pattern shapes of the 85 increases and the manufacturing cost of the common mode choke coil 80 increases.

Further, in the conventional common mode choke coil 80, the input / output external electrodes 93a to 94b are
Are provided on the upper surface and the mounting surface 95.
Is formed. These input / output external electrodes 93a-94b
Are close to the coil conductors 82 and 83 and part of the coil conductors 84 and 85 that constitute the coils L1 and L2, respectively. Therefore, a stray capacitance is generated between the input / output external electrodes 93a-94b and the coils L1 and L2, and the stray capacitance deteriorates the high frequency characteristics and lowers the common mode noise removal performance.

Further, a lead portion 82a of the coil conductor 82
The lead portion 84a of the coil conductor 84 does not face the stacking direction of the sheets 81, and the lead portion 83a of the coil conductor 83 and the lead portion 85a of the coil conductor 85 do not face the stacking direction of the sheet 81. Therefore, in the common mode choke coil 80, unnecessary normal mode component impedance is generated in the extraction portions 82a to 85a.

It is an object of the present invention to provide a common mode choke coil which is inexpensive to manufacture and has excellent high frequency characteristics.

[0011]

In order to achieve the above object, a common mode choke coil according to the present invention comprises: (a) a laminate formed by stacking a plurality of insulating layers and a plurality of coil conductors; b) a plurality of coils electrically connected to each other and magnetically coupled to each other, and (c) each of the plurality of coils is parallel to a mounting surface of the laminate. An input / output external electrode having a coil axis, wherein the coil conductor of each coil has the same pattern shape as the coil conductors of the other coils, and each of the plurality of coils has a lead portion formed on the mounting surface. Electrically connected to the

Since the coil conductors constituting each of the plurality of coils have the same pattern shape, the impedance of the normal mode component of each coil can be suppressed. In addition, the types of pattern shapes of the coil conductor are reduced. Further, since all of the input / output external electrodes are formed on the mounting surface, the stray capacitance generated between the external electrodes and the coil conductor is reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a common mode choke coil according to the present invention will be described with reference to the accompanying drawings.

[First Embodiment, FIGS. 1 to 3] As shown in FIG. 1, a laminated common mode choke coil 1 has insulating sheets 12, 13, 15 provided with coil conductors 23 to 26 on the surface thereof, respectively. , 16, a dummy sheet 14, a cover sheet 11, and the like. Coil conductor 23 ~
26, by a method such as printing, sputtering or vapor deposition,
It is formed on the surface of the insulating sheets 12, 13, 15, 16. As a material of the coil conductors 23 to 26, Ag,
Ag-Pd, Cu, Ni, etc. are used. Sheet 11
As the material 16, a magnetic material such as ferrite or an insulator material such as ceramic is used. Coil conductor 23,
Reference numeral 24 is electrically connected in series via a via hole 27 provided in the insulating sheet 12, and constitutes a spiral coil La whose winding direction is clockwise. One end of the coil La (that is, the lead portion 23a of the coil conductor 23) is exposed on the lower left side of the insulating sheet 12, and the other end (the coil conductor 24).
Of the insulating sheet 13 is exposed to the right side of the lower side.

The coil conductors 25 and 26 are electrically connected in series via a via hole 27 provided in the insulating sheet 15, and the spiral coil L is wound clockwise in a clockwise direction.
b. One end of the coil Lb (lead portion 25a of the coil conductor 25) is exposed on the lower left side of the insulating sheet 15, and the other end (lead portion 26a of the coil conductor 26) is exposed on the lower right side of the insulating sheet 16. I have.

The coil conductors 23 and 24 forming the coil La have exactly the same shape and dimensions as the coil conductors 25 and 26 forming the coil Lb. The coils La and Lb are magnetically coupled to each other.

After the above-mentioned insulating sheets 11 to 16 are stacked, they are integrally fired to form a laminate 28 as shown in FIG. FIG. 2 schematically shows the configuration of the common mode choke coil 1. The input external electrodes 2a, 3a are respectively provided on the left and right of the lower surface 30 (in other words, the mounting surface of the common mode choke coil 1) 30 of the multilayer body 28.
a and output external electrodes 2b and 3b. The input external electrode 2a and the output external electrode 2b are respectively connected to both ends of the coil La, specifically, the lead portion 2 of the coil conductor 23.
3a and the lead portion 24a of the coil conductor 24 are electrically connected. The input external electrode 3a and the output external electrode 3b
Both ends of the coil Lb, specifically, the coil conductor 2
5 and the lead portion 26a of the coil conductor 26
Is electrically connected to These input / output external electrodes 2
a to 3b are formed by applying a conductive paste of Ag, Ag-Pd, Cu, Ni, or the like, followed by baking or dry plating. FIG. 3 is an electric equivalent circuit diagram of the common mode choke coil 1.

As shown in FIG. 2, in the common mode choke coil 1 having the above configuration, the coil axes of the coils La and Lb are parallel to the stacking direction of the sheets 11 to 16 and the mounting surface 30 Is parallel to The coil axes of the coils La and Lb are the input / output external electrodes 2a to 3b.
Is parallel to The coil conductors 23 and 24 forming the coil La have exactly the same shape and dimensions as the coil conductors 25 and 26 forming the coil Lb. For this reason, the inductance of the normal mode component of the coil La becomes exactly equal to the inductance of the normal mode component of the coil Lb. Thus, when a normal mode signal flows through the coils La and Lb, it is possible to generate magnetic fluxes having equal magnitudes, opposite directions, and cancel each other in the coils La and Lb, and have almost no influence on the normal mode signal. It is possible to obtain the common mode choke coil 1 having no influence.

Moreover, the types of pattern shapes of the coil conductors are reduced, and the types of print masks for printing the coil conductors 23, 24, 25, 26 on the sheets 12, 13, 15, 16 are reduced. For example, in the first embodiment, if a print mask or a printed sheet is used upside down, all the coil conductors 23 to 26 can be formed by one type of mask.
Can be formed by printing. Thereby, the manufacture of the common mode choke coil 1 is simplified, and the manufacturing cost can be reduced.

Further, all the input / output external electrodes 2a to 3b
Are formed on the mounting surface 30, so that the input / output external electrodes 2
The stray capacitance generated between a to 3b and the coils La and Lb is reduced. Thereby, the inductance of the common mode component in the high frequency region can be increased, and the choke coil 1 having excellent common mode noise removal performance up to the high frequency region can be obtained.

The lead portion 23a of the coil conductor 23 and the lead portion 25a of the coil conductor 25 face in the direction in which the sheets 11 to 16 are stacked.
And the lead portion 26a of the coil conductor 26 also face the stacking direction of the sheets 11 to 16. Therefore, unlike the conventional common mode choke 80,
The common mode choke coil 1 of the embodiment can generate necessary impedance of the common mode component in the lead portions 23a to 26a. As a result, the common mode noise removal performance can be further improved.

[Second Embodiment, FIG. 4] FIG. 4 shows another embodiment of the common mode choke coil according to the present invention. The common mode choke coil 31 is different from the common mode choke coil 1 described with reference to FIGS. 1 and 2 in that the lamination position of the insulating sheet 15 provided with the coil conductor 25 and the lamination position of the insulating sheet 16 provided with the coil conductor 26. And has been changed. In FIG. 4, FIG.
Are denoted by the same reference numerals, and duplicate description will be omitted.

The coil conductors 25 and 26 are made of insulating sheet 1
6, and are electrically connected in series via a via hole 27, and constitute a spiral coil Lc whose winding direction is counterclockwise. Both ends of the coil Lc, specifically, the lead portion 25a of the coil conductor 25 and the lead portion 26a of the coil conductor 26 are electrically connected to the input external electrode 3a and the output external electrode 3b, respectively.

With the above configuration, the coil conductor 24 on the output side of the coil La and the coil conductor 26 on the output side of the coil Lc
Will be adjacent. By doing so, the magnetic coupling between the coil conductor 24 and the coil conductor 26 is increased, so that the common mode choke coil 1 of the first embodiment has an effect and the common mode noise elimination performance is further improved. .

[Third Embodiment, FIGS. 5 and 6] FIGS. 5 and 6 show another embodiment of the common mode choke coil according to the present invention. The common mode choke coil 41 is different from the common mode choke coil 1 described with reference to FIGS. 1 and 2 in that input / output external electrodes 2 a to 3 b are further provided on a surface 43 facing the mounting surface 30.
Can also be used as a mounting surface. 5 and FIG. 6, FIG. 1 and FIG.
Are denoted by the same reference numerals, and duplicate description will be omitted.

Leader portions 23a and 23b of coil conductor 23
Are exposed on the left side of the lower side and the upper side of the insulating sheet 12, respectively. Lead portions 24a, 2 of coil conductor 24
4b are exposed to the right of the lower side and upper side of the insulating sheet 13, respectively. Leader 25 of coil conductor 25
a and 25b are exposed to the left side of the lower side and upper side of the insulating sheet 15, respectively. The lead portions 26a and 26b of the coil conductor 26 are exposed on the lower side and the right side of the upper side of the insulating sheet 16, respectively. Here, the coil conductors 23 and 24 forming the coil La have exactly the same shape and dimensions as the coil conductors 25 and 26 forming the coil Lb.

The input external electrode 2a and the output external electrode 2b provided on the upper surface 43 of the laminate 28 are respectively provided at both ends of the coil La, specifically, a lead portion 23b of the coil conductor 23 and a lead portion 24b of the coil conductor 24. Are electrically connected. Similarly, the input external electrode 3a and the output external electrode 3b provided on the upper surface 43 of the laminate 28 are respectively provided with coils Lb
, Specifically, a lead portion 25b of the coil conductor 25
And the lead portion 26b of the coil conductor 26 are electrically connected.

With the above configuration, the upper surface 43 or the lower surface 30
Of the common mode choke coil 4 having no vertical direction
1 is obtained. As a result, in the common mode choke coil 41 of the third embodiment, in addition to the effects of the common mode choke coil 1 of the first embodiment, the degree of freedom in mounting is greatly improved.

[Other Embodiments] The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the gist.
For example, as shown in FIG. 7, in the common mode choke coil 1 described in FIG. 1, when a magnetic material is used as the material of the sheets 11 to 16, the coil conductors 23 to 2
Only the peripheral portions of the lead-out portions 23a to 26a may be non-magnetic portions 51 and 52 made of a non-magnetic material. With this configuration, the lead portions 23 of the coil conductors 23 to 26 are formed.
The inductance generated at a to 26a can be reduced, the generation of the impedance of the normal mode component is suppressed, and the deterioration of the signal waveform is suppressed.

In the above embodiment, the description has been given of the common mode choke coil having two coils. However, the present invention can be applied to a common mode choke coil having three or more coils.

Further, in the above-described embodiment, the insulating sheets on which the respective patterns are formed are stacked and then integrally fired, but the present invention is not necessarily limited to this.
As the insulating sheet, a pre-fired one may be used. Further, the choke coil may be formed by a manufacturing method described below. After an insulating layer is formed from a paste-like insulating material by a method such as printing, a paste-like conductive pattern material is applied to the surface of the insulating layer to form an arbitrary pattern. Next, a paste-like insulating material is applied from above the pattern to form an insulating layer in which the pattern is embedded.
Similarly, a choke coil having a laminated structure can be obtained by successively applying layers.

[0032]

As is clear from the above description, according to the present invention, since the coil conductors constituting each of the plurality of coils have the same pattern shape, the normal mode signal flows through each coil. In this case, magnetic fluxes acting on each coil so as to cancel each other are generated substantially equally.
Therefore, it is possible to obtain a common mode choke coil having little influence such as distorting a normal mode signal. In addition, the types of pattern shapes of the coil conductors are reduced, and accordingly, the manufacture of the common mode choke coil is simplified. Further, since all the input / output external electrodes are formed on the mounting surface, the stray capacitance generated between the input / output external electrodes and the coil conductor is reduced, and the high-frequency characteristics are improved. As a result, it is possible to obtain a common mode choke coil with low manufacturing cost and excellent performance.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration of a first embodiment of a common mode choke coil according to the present invention.

FIG. 2 is a perspective view of the common mode choke coil shown in FIG. 1;

FIG. 3 is an electric equivalent circuit diagram of the common mode choke coil shown in FIG.

FIG. 4 is a transparent perspective view of a second embodiment of the common mode choke coil according to the present invention.

FIG. 5 is an exploded perspective view showing a configuration of a third embodiment of the common mode choke coil according to the present invention.

FIG. 6 is a perspective view of the common mode choke coil shown in FIG. 5;

FIG. 7 is a perspective view of another embodiment of the common mode choke coil according to the present invention.

FIG. 8 is an exploded perspective view showing a configuration of a conventional common mode choke coil.

FIG. 9 is a perspective view of the common mode choke coil shown in FIG. 8;

[Explanation of symbols]

 1, 31, 41: common mode choke coil 2a, 3a: input external electrode 2b, 3b: output external electrode 11 to 16: insulating sheet 23 to 26: coil conductor 23a to 26a: lead-out section 28: laminated body 30: mounting Surface La, Lb, Lc ... coil

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-237106 (JP, A) JP-A-8-162328 (JP, A) JP-A-9-129447 (JP, A) JP-A-11-11 121251 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01F 17/00-17/08 H01F 27/00-30/16

Claims (4)

(57) [Claims] And 1. A laminate constituted by stacking a plurality of insulating layers and a plurality of coil conductors, said formed by connecting the coil conductors electrically, and a plurality of coils which are magnetically coupled to each other, the I / O external power provided substantially only on the mounting surface of the laminate
Poles, and each of the plurality of coils has a coil axis parallel to the mounting surface of the laminate, and the coil conductor of each coil has the same pattern shape as the coil conductor of the other coil. And a lead portion of each of the plurality of coils is pulled out to the same mounting surface and is electrically connected to the input / output external electrode. 2. A coil on an output side of each of the plurality of coils.
The conductor of claim 1 wherein the conductors are adjacent.
Common mode choke coil. 3. A laminate of a laminate facing a mounting surface of the laminate.
The second input / output external electrode is further provided substantially on the surface of
The drawer of each of the plurality of coils is also drawn to the second surface.
And is electrically connected to the second input / output external electrode.
And implements one of the mounting surface and the second surface.
3. A mounting surface as claimed in claim 1 or claim 2.
Common mode choke coil. 4. A circumference of each of the plurality of coils.
A non-magnetic material portion made of a non-magnetic material is formed on the side portion,
The laminated body is left except for the non-magnetic part and the coil conductor.
3. The method according to claim 1, wherein the material is made of a magnetic material.
The common mode choke coil according to claim 3.