JP2014207367A - Common mode choke coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a common mode choke coil capable of effectively removing a common mode noise.SOLUTION: A common mode choke coil 10 includes: a core 12 extending in a predetermined direction; and a coil 14 and a coil 16 wound around the core 12. A region E1 in which the coil 16 is wound around the core 12 and the coil 14 is wound around the coil 16 and a region E2 in which the coil 14 is wound around the core 12 and the coil 16 is wound around the coil 14 are provided.

Description

  The present invention relates to a common mode choke coil, for example, a wire wound common mode choke coil.

  As an invention related to a conventional common mode choke coil, for example, a common mode filter described in Patent Document 1 is known. In the common mode filter, a first winding is wound around the drum core, and a second winding is wound on the first winding.

  However, the common mode choke coil described in Patent Document 1 may not be able to effectively remove common mode noise. FIG. 5 is a graph showing the relationship between the position of the first winding and the potential and the relationship between the position of the second winding and the potential.

  In the common mode choke coil, the second winding is wound on the first winding. Therefore, the length of the second winding is longer than the length of the first winding. In this case, when a differential mode signal is transmitted to the first winding and the second winding, as shown in FIG. 5, the absolute potential is applied to one end of the first winding and one end of the second winding. Although the values are the same, the absolute values of the potentials are not always equal at the other end of the first winding and the other end of the second winding. For this reason, the differential mode signal is output as common mode noise.

JP 2005-56934 A

  Accordingly, an object of the present invention is to provide a common mode choke coil that can effectively remove common mode noise.

  A common mode choke coil according to an aspect of the present invention includes a core extending in a predetermined direction, and a first winding and a second winding wound around the core, A first region formed by winding the second winding on the core and winding the first winding on the second winding; and the first winding on the core. A second region that is wound and wound around the first winding is provided on the first winding.

  According to the present invention, common mode noise can be effectively removed.

It is a top view of the common mode choke coil which concerns on one Embodiment. It is a side view of the common mode choke coil which concerns on one Embodiment. It is a bottom view of the common mode choke coil which concerns on one Embodiment. 1B is a cross-sectional structural view taken along line AA in FIG. 1A. FIG. It is a bottom view of the common mode choke coil which concerns on a comparative example. It is a cross-section figure of a common mode choke coil concerning a comparative example. It is the graph which showed the electric potential of the coiling | winding when a differential mode signal is input into a common mode choke coil. It is the graph which showed the relationship between a frequency and Scd12. It is the graph which showed the relationship between a frequency and Sdd11.

  Below, the common mode choke coil which concerns on embodiment of this invention is demonstrated.

(Common mode choke coil configuration)
Below, the structure of the common mode choke coil 10 which concerns on one Embodiment is demonstrated, referring drawings. FIG. 1A is a top view of a common mode choke coil 10 according to an embodiment. FIG. 1B is a side view of the common mode choke coil 10 according to the embodiment. FIG. 1C is a bottom view of the common mode choke coil 10 according to the embodiment. FIG. 2 is a sectional structural view taken along line AA of FIG. 1A. Hereinafter, the longitudinal direction of the common mode choke coil 10 is defined as the left-right direction, and the directions orthogonal to the left-right direction are defined as the up-down direction and the front-rear direction.

  As shown in FIGS. 1A, 1B, 1C, and 2, the common mode choke coil 10 includes a core 12, windings 14 and 16, and external electrodes 18a, 18b, 20a, and 20b.

  The core 12 is made of a magnetic material (for example, NiCuZn-based ferrite), and has an H-shape when viewed from the upper side, the lower side, the front side, and the rear side. As shown in FIGS. 1A, 1B, 1C, and 2, the core 12 includes a core portion 12a and flange portions 12b and 12c.

  The winding core portion 12a has a quadrangular prism shape extending in the left-right direction. However, the core portion 12a may have another column shape such as a column shape.

  The flange portion 12b has a rectangular parallelepiped shape, and is connected to the left end of the core portion 12a. The flange portion 12b projects from the core portion 12a in the vertical direction and the front-rear direction when viewed from the left side.

  The collar portion 12c has a rectangular parallelepiped shape, and is connected to the right end of the core portion 12a. The flange portion 12c projects from the core portion 12a in the vertical direction and the front-rear direction when viewed from the right side.

  The external electrode 18a is provided in front of the center in the front-rear direction on the bottom surface of the flange 12b, and has a rectangular shape. The external electrode 18a is configured by performing Ni plating and Sn plating on a base electrode made of Ag.

  The external electrode 18b is provided in front of the center in the front-rear direction on the bottom surface of the flange 12c, and has a rectangular shape. The external electrode 18b is configured by performing Ni plating and Sn plating on a base electrode made of Ag.

  The external electrode 20a is provided behind the center in the front-rear direction on the bottom surface of the flange 12b, and has a rectangular shape. The external electrode 20a is configured by performing Ni plating and Sn plating on a base electrode made of Ag.

  The external electrode 20b is provided behind the center in the front-rear direction on the bottom surface of the flange 12c, and has a rectangular shape. The external electrode 20b is configured by performing Ni plating and Sn plating on a base electrode made of Ag.

  The windings 14 and 16 are wound around the core portion 12a of the core 12 so as to circulate in the same direction. In the present embodiment, the windings 14 and 16 are wound so as to advance while rotating in the same direction when viewed from the left.

  In the common mode choke coil 10, regions E1 and E2 are provided. The region E1 and the region E2 are adjacent to each other in the left-right direction. The region E1 is a region that occupies the left half of the core portion 12a. The region E2 is a region that occupies the right half of the core portion 12a. Therefore, the length in the left-right direction of the region E1 is equal to the length in the left-right direction of the region E2.

  In the region E1, as shown in FIG. 2, the winding 16 is wound on the winding core portion 12a, and the winding 14 is wound on the winding 16. That is, the winding 16 is located on the inner peripheral side with respect to the winding 14. As a result, the winding radius of the winding 14 is larger than the winding radius of the winding 16 in the region E1.

  On the other hand, in the region E2, as shown in FIG. 2, the winding 14 is wound on the winding core portion 12a, and the winding 16 is wound on the winding 14. That is, the winding 14 is located on the inner peripheral side of the winding 16. As a result, the winding radius of the winding 16 is larger than the winding radius of the winding 14 in the region E2.

  Further, both ends of the winding 14 are drawn from the core 12a. The left end of the winding 14 is connected to the external electrode 18a. The right end of the winding 14 is connected to the external electrode 18b.

  Further, both ends of the winding 16 are drawn from the core 12a. The left end of the winding 16 is connected to the external electrode 20a. The right end of the winding 16 is connected to the external electrode 20b.

  In the common mode choke coil 10 configured as described above, the windings 14 and 16 overlap when viewed in plan from the right side. Thereby, the magnetic flux generated by the winding 14 passes through the space surrounded by the winding 16, and the magnetic flux generated by the winding 16 passes through the space surrounded by the winding 14. Therefore, the winding 14 and the winding 16 are magnetically coupled, and the winding 14 and the winding 16 constitute a common mode choke coil. For example, the external electrodes 18a and 20a are used as input terminals, and the external electrodes 18b and 20b are used as output terminals. That is, a differential mode signal is input from the external electrodes 18a and 20a and output from the external electrodes 18b and 20b. When common mode noise is included in the differential mode signal, the windings 14 and 16 generate magnetic flux in the same direction due to the common mode noise. For this reason, the magnetic fluxes strengthen each other, an impedance to the common mode is generated, and the common mode noise is prevented from passing through the windings 14 and 16.

(Manufacturing method of coil parts)
Next, a method for manufacturing the common mode choke coil 10 will be described with reference to the drawings.

  First, a powder composed mainly of ferrite as a material for the core 12 is prepared. Then, the prepared ferrite powder is filled into a female mold. By pressing the filled powder with a male mold, the shape of the core portion 12a and the shapes of the flange portions 12b and 12c are formed. Further, the core 12 is fired. Thereby, the core 12 is completed.

  Then, external electrodes 18a, 18b, 20a, and 20b are formed on the bottom surfaces of the flange portions 12b and 12c of the core 12. Specifically, the bottom surfaces of the flanges 12b and 12c of the core 12 are immersed in a container filled with the Ag paste, and the Ag paste is attached to the bottom surface. Next, the attached Ag paste is dried and fired to form a base electrode on the bottom surfaces of the flanges 12b and 12c. Further, a Ni-based alloy metal film and a Sn-based alloy metal film are formed on the base electrode by electroplating or the like. Thus, the external electrodes 18a, 18b, 20a, and 20b are formed.

  Next, the windings 14 and 16 are wound around the core 12 a of the core 12. Specifically, after winding the winding 16 around the core 12a in the region E1, the winding 14 is wound on the winding 16 in the region E1. Next, after winding the winding 14 around the core 12a in the region E2, the winding 16 is wound on the winding 14 in the region E2. When winding the windings 14 and 16 around the core 12a, both ends of the windings 14 and 16 are pulled out from the core 12a by a predetermined amount.

  Finally, the drawn portions of the windings 14, 16 are connected to the external electrodes 18a, 18b, 20a, 20b by thermocompression bonding. Through the steps as described above, the common mode choke coil 10 is completed.

(effect)
According to the common mode choke coil 10 configured as described above, common mode noise can be effectively removed. FIG. 3 is a bottom view of the common mode choke coil 110 according to the comparative example. FIG. 4 is a cross-sectional structure diagram of the common mode choke coil 110 according to the comparative example. FIG. 5 is a graph showing the potentials of the windings 114 and 116 when a differential mode signal is input to the common mode choke coil 110.

  The common mode choke coil 110 includes a core 112 and windings 114 and 116. The winding 116 is wound around the core 112, and the winding 114 is wound on the winding 116.

  In the common mode choke coil 110 according to the comparative example, the length L1 of the winding 114 is longer than the length L2 of the winding 116. In this case, when a differential mode signal is transmitted to the winding 114 and the winding 116, the absolute values of the potentials are equal at the left end of the winding 114 and the left end of the winding 116 as shown in FIG. The absolute value of the potential is not always aligned at the right end of the winding and the right end of the winding 116. For this reason, the differential mode signal is output as common mode noise.

  On the other hand, in the common mode choke coil 10, in the region E1, the winding 16 is wound on the winding core portion 12a and the winding 14 is wound on the winding 16, as shown in FIG. As a result, the winding radius of the winding 14 is larger than the winding radius of the winding 16 in the region E1. In the region E2, as shown in FIG. 2, the winding 14 is wound on the winding core portion 12a, and the winding 16 is wound on the winding 14. As a result, the winding radius of the winding 16 is larger than the winding radius of the winding 14 in the region E2. As a result, the length of the winding 14 approaches the length of the winding 16. In the present embodiment, since the length of the region E1 in the left-right direction and the length of the region E2 in the left-right direction are equal, the length of the winding 14 and the length of the winding 16 are substantially equal. As a result, when the differential mode signal is transmitted to the winding 14 and the winding 16, the absolute values of the potentials at the respective times are aligned at the left end of the winding 14 and the left end of the winding 16, and the right end and the winding of the winding 14. At the right end of the line 16, the absolute value of the potential at each time is aligned. Therefore, the differential mode signal is suppressed from being output as common mode noise. As described above, the common mode choke coil 10 can effectively remove common mode noise.

  Here, the inventor of the present application conducted an experiment described below in order to clarify the effect of the common mode choke coil. First, the common mode choke coil 110 shown in FIGS. 3 and 4 is manufactured as the first sample, and the common mode choke coil 10 shown in FIGS. 1A, 1B, 1C, and 2 is manufactured as the second sample. did. The conditions for the first sample and the second sample are as follows.

Size: 4.5 × 3.2 × 2.6mm
Number of turns: 46 turns Wire diameter: 0.04 mm

  The S parameters of the first sample and the second sample as described above were measured. Specifically, Scd12 and Sdd11 of the first sample and the second sample were calculated. Scd12 is a parameter indicating the value of the ratio of the intensity of the common mode signal output from the external electrode 18a to the intensity of the differential mode signal input from the external electrode 18b. That is, Scd12 indicates the rate at which the differential mode signal is converted to the common mode signal. Sdd11 is a parameter indicating the value of the ratio of the intensity of the differential mode signal output from the external electrode 18a to the intensity of the differential mode signal input from the external electrode 18a. That is, Sdd11 indicates the reflection amount of the differential mode signal. FIG. 6 is a graph showing the relationship between frequency and Scd12. The vertical axis represents Scd12 and the horizontal axis represents frequency. FIG. 7 is a graph showing the relationship between the frequency and Sdd11. The vertical axis represents Sdd11 and the horizontal axis represents frequency.

  As shown in FIG. 6, it can be seen that Scd12 of the second sample is smaller than Scd12 of the first sample. Thereby, it can be seen that the differential mode signal is not converted into the common mode signal in the second sample than in the first sample. That is, it can be seen that common mode noise is more effectively removed in the common mode choke coil 10 than in the common mode choke coil 110.

  As shown in FIG. 7, it can be seen that Sdd11 of the second sample is smaller than Sdd11 of the first sample. Thus, it can be seen that the second sample reflects less differential mode signals than the first sample. The reason will be described below. As Scd12 becomes smaller, Sdc12 also becomes smaller for the same reason. That is, the value of the ratio of the intensity of the differential mode signal output from the external electrode 18a to the intensity of the common mode signal input from the external electrode 18b becomes small. Thereby, the intensity of the differential mode signal output from the external electrode 18a is reduced. Therefore, the value of the ratio of the intensity of the differential mode signal output from the external electrode 18a to the intensity of the common mode signal input from the external electrode 18b (that is, Sdd11) is also reduced. Thus, the second sample reflects less differential mode signals than the first sample.

(Other embodiments)
The common mode choke coil according to the present invention is not limited to the common mode choke coil 10 and can be changed within the scope of the gist thereof.

  Note that the length of the region E1 in the left-right direction and the length of the region E2 in the left-right direction may not be equal.

  One or more regions E1 and one or more regions E2 may be alternately arranged in the left-right direction. In this case, it is desirable that the total length in the left-right direction of the region E1 is equal to the total length in the left-right direction of the region E2.

  As described above, the present invention is useful for a common mode choke coil, and is particularly excellent in that common mode noise can be effectively removed.

10 Common mode choke coil 12 Core 14, 16 Winding 18a, 18b, 20a, 20b External electrode E1, E2 region

Claims (3)

A core extending in a predetermined direction;
A first winding and a second winding wound around the core;
With
A first region in which the second winding is wound on the core and the first winding is wound on the second winding; and the first winding on the core And a second region formed on the first winding and wound around the second winding,
A common mode choke coil. The length of the first region in a predetermined direction is equal to the length of the second region in a predetermined direction;
The common mode choke coil according to claim 1. A first external electrode and a second external electrode connected to both ends of the first winding;
A third external electrode and a fourth external electrode connected to both ends of the second winding;
Having
The common mode choke coil according to claim 1, wherein the common mode choke coil is characterized in that: