JPH1197244A - Laminated inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated inductor, wherein with a large current capacity, a floating capacity occurring between an external input electrode and an external output electrode is small. SOLUTION: A plurality of ceramic sheets 12, where a first coil conductor 11 is formed on each of them, constitute a first laminated part 31. The first coil conductors 11 are connected electrically in parallel, which constitutes a first coil conductor group 33a. A plurality of ceramic sheets 14, where a second coil conductor 13 is formed respectively, constituting a second laminated part 32. The second coil conductors 13 are connected electrically in parallel to constitute a second coil conductor group 33b. The first and second coil conductor groups 33a and 33b are electrically connected through a via hole 15 provided on a spacer ceramic sheet 21, forming a spiral coil 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laminated inductor, and more particularly to a laminated inductor used as a choke coil for a power supply line.

[0002]

2. Description of the Related Art As shown in FIG. 7, in a conventional laminated inductor 1, for example, a ceramic sheet 2 provided with a coil conductor 3 on its surface and a coil conductor 4 provided on its surface in order to increase the current capacity. It is known that a plurality of ceramic sheets 2 are alternately stacked. In this case, one end of each of the coil conductors 3 and 4 is electrically connected in series via the via hole 5 to form a plurality of spiral coils 7. The plurality of coils 7 are electrically connected in parallel between the external input electrode and the external output electrode of the multilayer inductor 1.

[0003]

By the way, for example, a potential difference occurs between the coil conductor 3 connected to the external input electrode and the coil conductor 4 connected to the external output electrode. A stray capacitance is generated between the coil conductors 3 and 4. However, in the conventional laminated inductor 1, since the coil conductors 3 and 4 are alternately arranged via the ceramic sheet 2, there are many places where the stray capacitance occurs, and between the external input electrode and the external output electrode. The generated total stray capacitance increases. As a result, there is a problem that the impedance of the inductor is reduced in a high frequency band.

An object of the present invention is to provide a multilayer inductor having a large current capacity and a small stray capacitance generated between an external input electrode and an external output electrode.

[0005]

In order to achieve the above object, a laminated inductor according to the present invention comprises: (a) a laminate of a plurality of first coil conductors and a plurality of ceramic layers; (B) a plurality of second coil conductors and a plurality of ceramic layers are laminated, and a first laminated portion containing a first coil conductor group formed by electrically connecting the first coil conductors in parallel; and A second laminated portion having a built-in second coil conductor group formed by electrically connecting the second coil conductors in parallel, and (c) a distance between the first coil conductor group and the second coil conductor group. D is between the first coil conductors or the second coil conductor.
With the distance between the coil conductors being larger than d, the first
The laminated part and the second laminated part are laminated, and the first coil conductor group and the second coil conductor group are electrically connected in series to form a coil. Specifically, the interval D is set to be at least twice the interval d.

[0006]

According to the above construction, the place where the stray capacitance is generated is mainly limited to the boundary between the first coil conductor group and the second coil conductor group. Moreover, since the distance D between the first coil conductor group and the second coil conductor group is relatively wide, the stray capacitance generated at the boundary between the first coil conductor group and the second coil conductor group can be reduced.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the multilayer inductor 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 multilayer inductor 10 has a plurality of ceramic sheets 12 provided with first coil conductors 11 having the same pattern shape, respectively. The same second coil conductor 13
, A ceramic sheet for spacers 21, a ceramic sheet for protection 16, and the like. Seats 12, 14, 16,
As the material of No. 21, for example, a Ni—Zn based or Ni—Cu
-A Zn-based magnetic material is used. First coil conductor 1
In 1, the drawer 11 a is exposed on the left side of the ceramic sheet 11. The second coil conductor 13 has a lead portion 13 a exposed on the right side of the ceramic sheet 14. The first and second coil conductors 11 and 13 are made of Ag, Ag
-Formed on the sheets 11 and 14 by a method such as a printing method using a conductive paste such as Pd and Cu.

The plurality of ceramic sheets 12 on which the first coil conductors 11 are respectively formed are first laminated portions 31.
Is composed. One end of each first coil conductor 11 is electrically connected to each other via a via hole 15 provided in the sheet 12 to form a first coil conductor group 33a. Similarly, the plurality of ceramic sheets 14 on which the second coil conductors 13 are respectively formed constitute a second laminated portion 32. One end of each second coil conductor 13 is
Are electrically connected to each other through a via hole 15 provided in the second coil conductor group 33b. further,
The first coil conductor group 33a and the second coil conductor group 33b
Via hole 1 provided in ceramic sheet 21 for spacer
And a helical coil 3 electrically connected in series
Form 3

Each ceramic sheet 12, 14, 16, 2
1 are stacked and integrally fired to form a laminate. Next, as shown in FIG. 2, the external input electrode 18 and the external output electrode 1
9 are provided. The external input electrode 18 is the first coil conductor 1
1 is electrically connected to the lead portion 11a of the external output electrode 1
Reference numeral 9 is electrically connected to the lead portion 13a of the second coil conductor 13. These electrodes 18 and 19 are made of Ag, Ag-
It is formed by applying and baking a conductive paste such as Pd or by dry plating.

The multilayer inductor 10 having the above configuration
As shown in FIG. 3, a spiral coil 33 having an axis parallel to the laminating direction of the ceramic sheets 12, 14, 16, 21 is formed inside the laminate 28. The direction of the axis of the spiral coil 33 is determined by the external input / output electrodes 18,
It is parallel to 19 planes.

Each of the plurality of first coil conductors 11 has a via hole 15 formed at one end thereof and a corresponding one of the lead portions 11a.
Are electrically connected in parallel with the external input electrode 18 to which the external input electrode 18 is connected. Similarly, a plurality of second coil conductors 1
Numeral 3 is electrically connected in parallel between a via hole 15 formed at one end thereof and an external output electrode 19 to which each lead portion 13a is connected. Thereby, the cross-sectional area of the coil 33 formed in the multilayer body 28 is substantially increased, and the current capacity of the multilayer inductor 10 can be increased.

The location where the stray capacitance occurs is mainly at the boundary between the first coil conductor group 33a and the second coil conductor group 33b, specifically, the ceramic sheet 12 provided with the first coil conductor 11 and the spacer. It is limited to the portion of the ceramic sheet 21. Moreover, the first coil conductor group 33a and the second
The spacer ceramic sheet 21 is disposed between the coil conductor groups 33b, and the distance D between the first coil conductor group 33a and the second coil conductor group 33b is set between the first coil conductors 11 or between the second coil conductors 13b. The distance is set so as to be larger than the distance d between them (D> d). As a result, the stray capacitance between the external input electrode 18 and the external output electrode 19 is reduced, a decrease in impedance in a high frequency region is suppressed, and the multilayer inductor 10 having good high-frequency characteristics can be obtained. In the first embodiment, the interval D is set to be at least twice the interval d (D> 2d), so that the stray capacitance between the external input electrode 18 and the external output electrode 19 is surely and stably reduced.

[Second Embodiment, FIGS. 4 to 6] In a second embodiment, a laminated inductor in which the axial direction of a built-in coil is perpendicular to the external input / output electrode surface will be described. As shown in FIG.
Are a plurality of ceramic sheets 42 provided with the first coil conductors 41 having the same pattern shape, a plurality of ceramic sheets 44 provided with the second coil conductors 43 having the same pattern shape, and a spacer provided with only the via hole 45. It is composed of a ceramic sheet 47, a protective ceramic sheet 46 provided with only via holes 45, and the like.

The plurality of ceramic sheets 42 on which the first coil conductors 41 are respectively formed are connected to the first laminated portion 51.
Is composed. The first coil conductors are electrically connected in parallel by connecting both ends thereof via via holes 45 provided in the sheet 42, thereby forming a first coil conductor group 53a. Similarly, the second coil conductor 4
The plurality of ceramic sheets 44 on which the respective layers 3 are formed constitute a second laminated portion 52. The second coil conductors 43 are electrically connected in parallel by connecting both ends thereof via via holes 45 provided in the sheet 44 to form a second coil conductor group 53b. Further, the first coil conductor group 53a and the second coil conductor group 53b are electrically connected in series via a via hole 45 provided in the ceramic sheet 47 for a spacer to form a spiral coil 53.

Each of the ceramic sheets 42, 44, 46, 4
7 are stacked and integrally fired to form a laminate. Next, as shown in FIG. 5, the external input electrode 68 and the external output
9 are provided. The external input electrode 68 is electrically connected to an end of the first coil conductor 41 via a via hole 45 provided in the sheet 46 provided on the rightmost outermost layer of the stacked body 58. The external output electrode 69 is electrically connected to the end of the second coil conductor 43 via the via hole 45 provided in the sheet 46 provided on the outermost layer on the left side of the multilayer body 58.

The multilayer inductor 40 having the above configuration
As shown in FIG. 6, a spiral coil 53 having an axis parallel to the laminating direction of the ceramic sheets 42, 44, 46, 47 is formed inside a laminate 58. The direction of the axis of the spiral coil 53 is determined by the external input / output electrodes 68,
Perpendicular to the 69 plane.

Further, a spacer ceramic sheet 47 is provided between the first coil conductor group 53a and the second coil conductor group 53b, and a distance D between the first coil conductor group 53a and the second coil conductor group 53b is provided. Is set to be larger than the distance d between the first coil conductors 41 or between the second coil conductors 43 (D> d). The multilayer inductor 40 according to the second embodiment has substantially the same operation and effect as the multilayer inductor 10 according to the first embodiment.

[Other Embodiments] The multilayer inductor according to the present invention is not limited to the above-described embodiment.
Various changes can be made within the scope of the gist. In the above-described embodiment, the ceramic sheets 12, 14 and the like are made of a magnetic material. However, the ceramic sheets 12, 14 and the like are made of a normal dielectric material, and a so-called empty space is formed inside the ceramic laminate. The present invention can be applied to a laminated inductor having a core coil.

In the above embodiment, the ceramic sheets on which the respective patterns are formed are stacked and then integrally fired, but the invention is not necessarily limited to this. A ceramic sheet that has been fired in advance may be used. Further, the inductor may be manufactured by a manufacturing method described below. After a ceramic layer is formed from a paste-like ceramic material by printing or the like, an arbitrary pattern is formed by applying a paste-like conductive pattern material to the surface of the ceramic layer. Next, a paste-like ceramic material is applied from above the pattern to form a ceramic layer in which the pattern is embedded. Similarly, in order,
An inductor having a laminated structure can be obtained by applying the layers repeatedly.

[0021]

As is apparent from the above description, according to the present invention, the first coil conductor group in which the first coil conductors are electrically connected in parallel and the second coil conductor are electrically connected in parallel. The coil is formed by electrically connecting the second coil conductor group connected to the coil in series, so that a coil having a substantially large sectional area can be obtained, and a laminated inductor having a large current capacity can be obtained. it can.

Further, in a state where the distance D between the first coil conductor group and the second coil conductor group is larger than the distance d between the first coil conductors or the distance between the second coil conductors, the first laminated portion and the second laminated portion are separated. Since the parts are stacked, the location where the stray capacitance occurs is mainly limited to the boundary between the first coil conductor group and the second coil conductor group. Moreover, since the distance D between the first coil conductor group and the second coil conductor group is relatively wide, the stray capacitance generated at the boundary between the first coil conductor group and the second coil conductor group can be reduced.

As a result, the stray capacitance between the external input electrode and the external output electrode is reduced, and a device having excellent impedance characteristics in a high frequency region can be obtained. Further, by setting the interval D to be at least twice the interval d, the stray capacitance between the external input / output electrodes can be reliably and stably reduced.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of a multilayer inductor according to the present invention.

FIG. 2 is an external perspective view of the multilayer inductor shown in FIG.

FIG. 3 is a sectional view illustrating the structure of the multilayer inductor shown in FIG. 2;

FIG. 4 is an exploded perspective view showing a second embodiment of the multilayer inductor according to the present invention.

5 is an external perspective view of the multilayer inductor shown in FIG.

FIG. 6 is a sectional view for explaining the structure of the multilayer inductor shown in FIG. 5;

FIG. 7 is an exploded perspective view showing a conventional multilayer inductor.

[Explanation of symbols]

 10, 40 ... laminated inductor 11, 41 ... first coil conductor 12, 42 ... ceramic sheet 13, 43 ... second coil conductor 14, 44 ... ceramic sheet 15, 45 ... via hole 18 ... external input electrode 19 ... external output electrode 21, 47: Ceramic sheet for spacer 31, 51: First laminated portion 32, 52: Second laminated portion 33a, 53a: First coil conductor group 33b, 53b: Second coil conductor group 33, 53: Helical coil

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kotobuki Katsuta 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd.

Claims (2)

[Claims] A first built-in first coil conductor group formed by laminating a plurality of first coil conductors and a plurality of ceramic layers and electrically connecting the first coil conductors in parallel; A second laminate including a laminated portion, a plurality of second coil conductors and a plurality of ceramic layers laminated, and a second coil conductor group formed by electrically connecting the second coil conductors in parallel. And a distance D between the first coil conductor group and the second coil conductor group.
The first laminated portion and the second laminated portion are laminated in a state in which the distance between the first coil conductors or the distance d between the second coil conductors is larger, and the first coil conductor group and the A second coil conductor group is electrically connected in series to form a coil. 2. The multilayer inductor according to claim 1, wherein the distance D is at least twice the distance d.