JPH08186034A - Wound coil component - Google Patents

Abstract

PURPOSE: To lessen the mounting area of a wound coil component and/or to contrive to enhance the noise removal performance of the coil component. CONSTITUTION: A coil component (a common-mode choke coil) is formed by winding two wires 21 and 22 on a drum part 11 of a ferrite core 10 into a bifilar winding. Electrodes 15a and 16a and 15b and 16b are respectively formed on both side surfaces of a flange 13 of the core 10. A starting end 21a and a terminal 21b of the wire 21 are respectively connected with the electrodes 15a and 15b and a starting end 22a and a terminal 22b of the wire are respectively connected with the electrodes 16a and 16b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire-wound coil component, and more particularly to a coil component used as a choke coil for removing common mode noise.

[0002]

2. Description of the Related Art Conventionally, as a choke coil for removing common mode noise in a high frequency circuit, as shown in FIG. 6, two wires are wound around a body portion 2 of a ferrite core 1 in a bifilar single-layer arrangement, and each wire is wound. Four electrodes 4a, 4b, 5 having the start and end of each of them on the bottom surface of the flange 3
The one connected to each of a and 5b is provided.
This choke coil has a resonance frequency of about 100, for example.
MHz, the height T is 4.0 mm, the length L of the flange 3 is 5.0 mm, the width W is 3.6 mm, and the distance D between the electrodes is 0.8 mm, and each electrode 4a, 4b, 5a, 5b. Has an area of 1.0 mm ² .

[0003]

By the way, in the conventional choke coil, the electrodes 4a, 4b, 5 are formed on the bottom surface of the flange 3.
Since the electrodes a and 5b are provided and the electrodes require a certain area, it is difficult to make the flange 3 itself small, which is a major obstacle to miniaturization of the choke coil (reduction of mounting area). It was

That is, the electrode 4 to which the starting end of each wire is connected
Stray capacitance is generated between a and 5a and the electrodes 4b and 5b to which the ends are connected, and this stray capacitance deteriorates the noise removal performance in a high frequency region. In the conventional choke coil, the distance D between the electrodes is 0.8 mm, and this value is said to be the limit of downsizing.

Therefore, an object of the present invention is to provide a wire-wound coil component which can reduce the mounting area and / or improve the noise removal performance.

[0006]

In order to achieve the above object, in the wire wound coil component according to the present invention, the starting end and the terminating end of two wires wound around the body of the core are provided on the side surface of the flange of the core. Connected to each of the four electrodes provided,
It is characterized in that the electrodes to which the starting ends of the two wires are connected and the electrodes to which the ends thereof are connected are respectively provided on side surfaces of the flange which are located on opposite sides.

[0007]

In the above structure, since the electrodes connecting the starting end and the terminating end of each of the two wires are provided on the side surfaces of the flange which are located on opposite sides, the distance between the electrodes is the distance between the side surfaces of the flange. Is equal to That is, the stray capacitance decreases as the distance between the electrodes increases, the insertion loss in the high frequency region increases, and the noise removal performance improves. On the other hand, even if the distance between the side surfaces of the flange is set small, the required insertion loss level can be maintained, and the mounting area is reduced by the size of the flange, which contributes to high-density mounting.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the wire wound coil component according to the present invention will be described below with reference to the accompanying drawings. 1 and 2 show the configuration of a common mode choke coil according to an embodiment of the present invention, which includes a ferrite core 10 and two wires 21,
22 and 22. Note that the wires are not shown in FIG. 1 for simplification.

The ferrite core 10 comprises a body 11 and upper and lower flanges 12, 13. Lower flange 1
Electrodes 15a, 15b, 16a, 16b are formed on side surfaces 13a, 13b located on the opposite sides of 3, by coating / baking of a conductive paste, sputtering of a conductive material, or the like. The wires 21 and 22 are wound around the body 11 by bifilar single-layer aligned winding. Wire 2
The starting end 21a and the terminating end 21b of the wire 1 are connected to the electrodes 15a and 15b, respectively.
Are connected to the electrodes 16a and 16b, respectively. The connection is made by thermocompression bonding or soldering.

FIG. 3 shows an equivalent circuit of the common mode choke coil having the above structure. The wires 21 and 22 function as inductors and reduce common mode noise. In this case, between the electrodes 15a, 15b and 16a, 16
Stray capacitance C is generated between points b, and the insertion loss in the high frequency region is deteriorated.

In this embodiment, when other conditions are the same and the distance between the electrodes is changed, the stray capacitance generated between the electrodes is as shown in FIG. When the distance between the electrodes is 0.8 mm, which is the same as the conventional example shown in FIG. 6, the stray capacitance is 0.53 pF.
Is. If the distance between the electrodes is increased to 1.8 mm, the stray capacitance is reduced to 0.44 pF, and if it is increased to 3.6 mm which is the width dimension of the flange 13, the stray capacitance is reduced to 0.4 mm.
It is reduced to 1 pF.

Numerical examples regarding the height T of the choke coil, the length L of the flange, the width W, and the distance D between the electrodes are shown in Table 1 below.

[0013]

[Table 1]

FIG. 5 shows the noise elimination characteristics of Examples 1, 2 and 3, and the curve shows the characteristic of Example 1, which is the same as the characteristic of the conventional choke coil shown in FIG. The curve shows the characteristics of Example 2. The curve shows the characteristics of Example 3. Example 3 is shown in Figure 1.
In the choke coil shown in FIG. 2, the width W of the flange 13 in Example 2 is halved.

Example 1 has the same insertion loss and noise reduction characteristics as the conventional example, but the area of the flange (mounting area) is 1 /
It will be 4.5. In Example 2, the mounting area is halved, the stray capacitance is reduced by 85%, and the insertion loss is improved by 1.5 dB. Example 3 has the same mounting area as the conventional example, but the stray capacitance is 77
%, And the insertion loss is improved by 2 dB.

The choke coil according to the present invention is not limited to the above embodiment, but can be variously modified within the scope of the invention. For example, if the interelectrode distance D is sufficiently large, the electrodes provided on the side surfaces of the flange may be extended to the bottom surface of the flange. Further, each electrode may be provided on each of the four side surfaces of the flange. Specifically, when the electrode 15a is provided on the side surface 13a, the electrode 1
6a is provided on the opposite side surface 13b, and the electrode 15
b and 16b, side surfaces 13c and 1 located on opposite sides, respectively.
It is provided in 3d.

[0017]

As is apparent from the above description, according to the present invention, the electrodes to which the starting ends and the terminating ends of the two wires are connected are provided on the side surfaces of the flange which are located on opposite sides of each other. It is possible to increase the distance between the electrodes to which the start ends of the cables are connected and the distance between the electrodes to which the terminals are connected to the distance between the side surfaces of the flange. By reducing the stray capacitance, noise removal performance is improved in the high frequency range Can be achieved. On the other hand, the distance between the side surfaces of the flange can be reduced within a range in which the stray capacitance does not increase more than necessary,
As a result, the mounting area of the coil component is reduced, which contributes to high-density mounting.

[Brief description of drawings]

FIG. 1 is a perspective view of a common mode choke coil that is an embodiment of the present invention, and wires are omitted.

FIG. 2 is a bottom view of the common mode choke coil.

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

FIG. 4 is a graph showing a relationship between a distance between electrodes and a stray capacitance.

FIG. 5 is a graph showing insertion loss of a common mode choke coil.

FIG. 6 is a perspective view of a conventional common mode choke coil,
Wires are omitted.

[Explanation of symbols]

 10 ... Core 11 ... Body part 13 ... Flange 13a, 13b, 13c, 13d ... Side surface 15a, 15b, 16a, 16b ... Electrode 21,22 ... Wire 21a, 22a ... Start end 21b, 22b ... Termination

Claims (1)

[Claims] 1. A wire-wound coil component in which two wires are wound around a body of a core, wherein four electrodes are provided on a side surface of a flange of the core, and a start end and an end of the wire are respectively connected to the electrodes. And an electrode to which a starting end of each of the two wires is connected and an electrode to which an end of each of the two wires are connected are provided on side surfaces of the flange that are located on opposite sides of each other, respectively. .