Coil component and filter circuit comprising same

Abstract

The present disclosure provides a coil component which generates different mutual inductance according to a connection path and a filter circuit comprising same. The coil component (10) of the present disclosure comprises: an insulator (1) having a first main surface (11A) and a second main surface (11B), and four side surfaces (12A-12D); a first coil (L1) disposed inside the insulator (1); and a second coil (L2) which is magnetically coupled with the first coil (L1). The first coil (L1) includes a first conductor pattern (2a) - a third conductor pattern (2c). The second coil (L2) includes a fourth conductor pattern (3a) – a sixth conductor pattern (3c). The second conductor pattern (2b) is derived from the position of the second side surface (12B) in a fourth side surface (12D) side from the fifth conductor pattern (3b), and the third conductor pattern (2c) is derived from the position of the third side surface (12C) in a fourth side surface (12D) side from the sixth conductor pattern (3c).

Description

Coil components and filter circuits including them

[0001] The present disclosure relates to a coil component and a filter circuit including the same.

[0002] In electronic devices, noise suppression using filter circuits is often used. Examples of filter circuits used for noise suppression include EMI (Electro-Magnetic Interference) filters, which allow necessary components of the current flowing through a conductor to pass through, while removing unnecessary components. Furthermore, because filter circuits use capacitors, which are capacitance elements, it is known that the noise suppression effect is reduced by the equivalent series inductance (ESL), which is the parasitic inductance of the capacitor.

[0003] A technology is known in which the mutual inductance (negative inductance) generated in a coil component in which two coils are magnetically coupled cancels out the equivalent series inductance (ESL) of a capacitor, thereby broadening the bandwidth of the noise suppression effect of a filter circuit (for example, International Publication No. 2021 / 053915: Patent Document 1).

[0004] International Publication No. 2021 / 053915

[0005] However, the value of the parasitic inductance generated in a filter circuit varies depending on the capacitors and board wiring used. Therefore, in order to determine the optimal mutual inductance for canceling the parasitic inductance generated in the filter circuit, it was necessary to prepare and test coil components having different mutual inductances. In the coil component structure described in International Publication No. 2021 / 053915 (Patent Document 1), the generated mutual inductance value was one, so it was necessary to prepare coil components for the number of mutual inductances required for testing.

[0006] Therefore, an object of the present disclosure is to provide a coil component that generates different mutual inductance depending on the connection path, and a filter circuit including the coil component.

[0007] A coil component according to one embodiment of the present disclosure includes a housing having a pair of opposing first and second main surfaces and four side surfaces connecting the first and second main surfaces, a first coil disposed inside the housing, and a second coil magnetically coupled to the first coil. The first coil includes a first conductor pattern extending from a first side surface of the housing, a second conductor pattern extending from the first conductor pattern toward the second side surface, and a third conductor pattern extending from the first conductor pattern toward a third side surface opposite the second side surface. The second coil includes a fourth conductor pattern extending from a fourth side surface opposite the first side surface of the housing, a fifth conductor pattern extending from the second conductor pattern toward the second side surface, and a sixth conductor pattern extending from the second conductor pattern toward the third side surface. The second conductor pattern extends from a position on the second side surface closer to the fourth side surface than the fifth conductor pattern, and the third conductor pattern extends from a position on the third side surface closer to the fourth side surface than the sixth conductor pattern.

[0008] A filter circuit according to one embodiment of the present disclosure includes the above-described coil component and a capacitor electrically connected to the second conductor pattern and the fifth conductor pattern of the coil component, or electrically connected to the third conductor pattern and the sixth conductor pattern of the coil component.

[0009] According to one embodiment of the present disclosure, the coil component can generate different mutual inductances depending on whether the coil component is electrically connected to the second conductor pattern and the fifth conductor pattern or the coil component is electrically connected to the third conductor pattern and the sixth conductor pattern.

[0010] 1 is a perspective view of a coil component according to a first embodiment. FIG. 2 is a schematic diagram of the coil component according to the first embodiment. FIG. 3 is a circuit diagram of a filter circuit including the coil component according to the first embodiment. FIG. 4 is a schematic diagram for explaining a connection path between the coil component according to the first embodiment and a land electrode of a substrate. FIG. 5 is a schematic diagram for explaining another connection path between the coil component according to the first embodiment and a land electrode of a substrate. FIG. 6 is a schematic diagram for explaining yet another connection path between the coil component according to the first embodiment and a land electrode of a substrate. FIG. 7 is a schematic diagram of a coil component according to a second embodiment. FIG. 8 is a schematic diagram of a coil component according to a third embodiment. FIG. 9 is a schematic diagram for explaining a connection path between the coil component according to the third embodiment and a land electrode of a substrate. FIG. 10 is a schematic diagram of a coil component according to a fourth embodiment. FIG. 11 is an exploded plan view showing the configuration of the coil component according to the fourth embodiment. FIG. 12 is a schematic diagram of a coil component according to the fourth embodiment.

[0011] Hereinafter, a coil component according to the present disclosure and a filter circuit including the coil component will be described with reference to the drawings.

[0012] First Embodiment First, a coil component according to the first embodiment will be described with reference to the drawings. Fig. 1 is a perspective view of a coil component 10 according to the first embodiment. Fig. 2 is a schematic diagram of the coil component 10 according to the first embodiment. Fig. 3 is a circuit diagram of a filter circuit 100 including the coil component 10 according to the first embodiment. Note that with respect to the X-axis, Y-axis, and Z-axis defined in Fig. 1, the X-axis direction represents the front-rear direction of the coil component 10, the Y-axis direction represents the left-right direction of the coil component 10, and the Z-axis direction represents the up-down direction of the coil component 10, respectively.

[0013] The coil component 10 is, for example, a transformer coil mounted in a filter circuit 100 used to reduce noise in a power line. As will be described later, the coil component 10 magnetically couples two coils to cancel the parasitic inductance of a capacitor mounted in the filter circuit 100.

[0014] The coil component 10 is a rectangular parallelepiped chip component in which two coils are stacked in the Z direction. As shown in FIG. 1 , the coil component 10 is composed of an insulator 1 (housing) in which multiple insulating substrates (insulator layers) on which coil conductor patterns are formed are stacked. The insulating substrates are stacked in the Z direction, with the arrow pointing upward. The insulating substrates are made of materials such as an insulating material primarily composed of borosilicate glass, or insulating resins such as alumina, zirconia, or polyimide resin. Furthermore, the interfaces between the multiple insulating substrates in the insulator 1 may be unclear due to processes such as firing and curing.

[0015] The insulator 1 has a pair of opposing first and second main surfaces 11A and 11B, and four side surfaces (a first side surface 12A, a second side surface 12B, a third side surface 12C, and a fourth side surface 12D) connecting the first and second main surfaces 11A and 11B. The first main surface 11A is also referred to as a top surface, and the second main surface 11B is also referred to as a bottom surface.

[0016] 1 , the coil component 10 has an external electrode 4a (first external electrode) arranged on the first side surface 12A, an external electrode 4c (second external electrode) and an external electrode 4e (fifth external electrode) arranged on the second side surface 12B, an external electrode 4d (third external electrode) and an external electrode 4f (sixth external electrode) arranged on the third side surface 12C, and an external electrode 4b (fourth external electrode) arranged on the fourth side surface 12D. The external electrodes 4a to 4f form electrodes not only on the side surfaces of the insulator 1 but also partially on the top and bottom surfaces of the insulator 1.

[0017] The coil component 10 includes two coils, a first conductor 2 that forms the first coil L1 and a second conductor 3 that forms the second coil L2, enclosed in an insulator 1, and the first coil L1 and the second coil L2 are magnetically coupled to form a transformer. Note that, although the first embodiment describes an example of the coil component 10 in which the first coil L1 and the second coil L2 form a transformer, the coil component 10 does not necessarily have to form a transformer as long as the first coil L1 and the second coil L2 are magnetically coupled.

[0018] The first conductor 2 of the first coil L1 is electrically connected to the external electrode 4a on the first side surface 12A, and is further electrically connected to the external electrode 4c on the second side surface 12B and to the external electrode 4d on the third side surface 12C. The second conductor 3 of the second coil L2 is electrically connected to the external electrode 4b on the fourth side surface 12D, and is further electrically connected to the external electrode 4e on the second side surface 12B and to the external electrode 4f on the third side surface 12C.

[0019] Next, the specific configurations of the first conductor 2 and the second conductor 3 will be described. The first conductor 2 and the second conductor 3 are each formed on one of multiple insulating substrates (e.g., ceramic green sheets) constituting the insulator 1. The first conductor 2 and the second conductor 3 are formed by printing, for example, a conductive paste (Ni paste) on the insulating substrate using a screen printing method. FIG. 2( a) is a diagram of the first conductor 2 and the second conductor 3 as viewed from the top surface of the coil component 10 (as viewed from the direction of the first main surface 11A). FIG. 2( b) is a plan view of the first conductor 2 formed on the insulating substrate 1b, and FIG. 2( c) is a plan view of the second conductor 3 formed on the insulating substrate 1c. The coil component 10 is formed by stacking and pressure-bonding multiple insulating substrates, including the insulating substrate 1b and the insulating substrate 1c, and then firing the stack, followed by baking external electrodes onto the side surfaces.

[0020] As shown in FIG. 2( a), the coil component 10 has external electrodes 4a and 4b provided on the side surfaces of the short sides (first side surface 12A, fourth side surface 12D), and external electrodes 4c to 4f provided on the side surfaces of the long sides (second side surface 12B, third side surface 12C). The external electrodes 4a and 4b are provided so as to cover the entire short side surfaces, while the external electrodes 4c to 4f are provided on only part of the long side surfaces. Specifically, the external electrode 4e provided on the second side surface 12B is located at a position (first position) closer to the first side surface 12A, and the external electrode 4c provided on the second side surface 12B is located at a position (second position) closer to the fourth side surface 12D. Furthermore, the position of the external electrode 4f provided on the third side surface 12C is at a position (third position) closer to the first side surface 12A, and the position of the external electrode 4d provided on the third side surface 12C is at a position (fourth position) closer to the fourth side surface 12D.

[0021] The distance from the fourth side surface 12D to the position of the external electrode 4c is approximately the same as the distance from the first side surface 12A to the position of the external electrode 4f, and the distance from the first side surface 12A to the position of the external electrode 4e is approximately the same as the distance from the fourth side surface 12D to the position of the external electrode 4d. In other words, the positions of the external electrodes 4c and 4e on the second side surface 12B and the positions of the external electrodes 4d and 4f on the third side surface 12C are point-symmetric when viewed from the direction of the first main surface 11A. Therefore, as will be described later, the coil component 10 can be connected to the land electrodes of the substrate even if it is rotated 180 degrees in a plane parallel to the substrate.

[0022] Next, as shown in FIG. 2( b), the first conductor 2 is a T-shaped conductor pattern formed on the insulating substrate 1b and includes a first conductor pattern 2a, a second conductor pattern 2b, and a third conductor pattern 2c. The first conductor pattern 2a is drawn out from the first side surface 12A of the insulator 1 and electrically connected to the external electrode 4a. The second conductor pattern 2b extends from an end of the first conductor pattern 2a toward the second side surface 12B, drawn out from the second side surface 12B, and electrically connected to the external electrode 4c. The third conductor pattern 2c extends from an end of the first conductor pattern 2a toward the third side surface 12C, drawn out from the third side surface 12C, and electrically connected to the external electrode 4d. The length D1 of the second conductor pattern 2b is longer than the length D2 of the third conductor pattern 2c. In other words, the first conductor pattern 2a is formed closer to the third side surface 12C than the second side surface 12B.

[0023] As shown in FIG. 2( c), the second conductor 3 is a T-shaped conductor pattern formed on the insulating substrate 1c and includes a fourth conductor pattern 3a, a fifth conductor pattern 3b, and a sixth conductor pattern 3c. The fourth conductor pattern 3a is drawn out from the fourth side surface 12D of the insulator 1 and electrically connected to the external electrode 4b. The fifth conductor pattern 3b extends from an end of the fourth conductor pattern 3a toward the second side surface 12B, drawn out from the second side surface 12B, and electrically connected to the external electrode 4e. The sixth conductor pattern 3c extends from an end of the fourth conductor pattern 3a toward the third side surface 12C, drawn out from the third side surface 12C, and electrically connected to the external electrode 4f. The length D1 of the fifth conductor pattern 3b is longer than the length D2 of the sixth conductor pattern 3c. In other words, the fourth conductor pattern 3a is formed closer to the third side surface 12C than the second side surface 12B.

[0024] As shown in FIG. 2( b ), the first conductor 2 is configured such that the first conductor pattern 2a is divided into the second conductor pattern 2b and the third conductor pattern 2c closer to the fourth side face 12D than the center of the insulating substrate 1b. As shown in FIG. 2( c ), the second conductor 3 is configured such that the fourth conductor pattern 3a is divided into the fifth conductor pattern 3b and the sixth conductor pattern 3c closer to the first side face 12A than the center of the insulating substrate 1c. Therefore, the second conductor pattern 2b is drawn out from a position on the second side face 12B closer to the fourth side face 12D than the fifth conductor pattern 3b, and the third conductor pattern 2c is drawn out from a position on the third side face 12C closer to the fourth side face 12D than the sixth conductor pattern 3c. As a result, when the coil component 10 is viewed from the top surface as shown in FIG. 2( a ), a portion of the first conductor pattern 2a and a portion of the fourth conductor pattern 3a overlap. The first coil L1 (first conductor 2) and the second coil L2 (second conductor 3) are magnetically coupled by a part of the overlapping first conductor pattern 2a and a part of the overlapping fourth conductor pattern 3a.

[0025] Next, a filter circuit 100 will be described that incorporates the coil component 10, in which two coils are magnetically coupled as described above. The filter circuit 100 is, for example, an EMI removal filter, as shown in FIG. 3 , and is a third-order T-type LC filter circuit. In this filter circuit 100, the external electrode 4 a of the coil component 10 is connected to a power supply (not shown), and the external electrode 4 b is connected to a circuit (not shown), such as a DC / DC converter or a power supply module. The filter circuit 100 passes necessary components of the current flowing from the power supply to the circuit and removes unnecessary components. Specifically, a direct current is passed through the filter circuit 100, and high-frequency noise contained in the direct current is dropped to GND via a capacitor C1.

[0026] The capacitor C1, which is a capacitance element, has an equivalent series inductance ESL (La) of the capacitor C1, which prevents high-frequency noise from passing through, resulting in a deterioration of noise removal performance. This filter circuit 100 uses the negative inductance generated by the magnetic coupling between the two coils to cancel the ESL (La) of the capacitor C1 and maintain high noise removal performance. In this disclosure, the negative inductance generated in series with the capacitor C1 is referred to as the mutual inductance M of the coil component 10. As will be described later, the mutual inductance M of the coil component 10 can be changed by changing the connection path.

[0027] In the following embodiments, a third-order T-type LC filter circuit will be used as the configuration of the filter circuit 100, but coil components of a similar configuration can also be applied to fifth-order T-type LC filter circuits or higher-order T-type LC filter circuits. As shown in Fig. 3, the filter circuit 100 includes a capacitor C1, external electrodes 4a and 4b, an intermediate terminal T (external electrodes 4c and 4e, or external electrodes 4d and 4f), a first coil L1, and a second coil L2.

[0028] As shown in FIG. 3, one end of the capacitor C1 is connected to the intermediate terminal T, and the other end is connected to the GND wiring. The capacitor C1 is made of BaTiO ３The present invention is not limited to multilayer ceramic capacitors primarily composed of barium titanate (barium titanate), but may also include multilayer ceramic capacitors primarily composed of other materials, or other types of capacitors other than multilayer ceramic capacitors, such as aluminum electrolytic capacitors. Capacitor C1 has an inductor La as a parasitic inductance (equivalent series inductance (ESL)), and is equivalent to a circuit configuration in which inductor La is connected in series with capacitor C1a. Capacitor C1 may also be equivalent to a circuit configuration in which parasitic resistance (equivalent series resistance (ESR)) is connected in series with inductor La and capacitor C1a.

[0029] In addition to the capacitor C1, a first coil L1 and a second coil L2 are connected to the intermediate terminal T. The first coil L1 and the second coil L2 are magnetically coupled and have a mutual inductance M. A negative inductance component equal in magnitude to the mutual inductance M is generated between the intermediate terminal T and the capacitor C1. This negative inductance component can be used to cancel out the parasitic inductance (inductor La) of the capacitor C1, thereby making the parasitic inductance component of the capacitor C1 appear smaller. In other words, the filter circuit 100, which is composed of the capacitor C1, the first coil L1, and the second coil L2, cancels out the parasitic inductance of the capacitor C1 with the negative inductance component due to the mutual inductance M between the first coil L1 and the second coil L2. This prevents a reduction in the noise suppression effect in the high frequency band caused by the parasitic inductance of the capacitor C1, thereby improving the noise suppression effect of the filter circuit 100.

[0030] However, the value of the parasitic inductance occurring in the filter circuit 100 varies depending on the capacitor C1 and board wiring used. Therefore, in order to determine the optimal mutual inductance M for canceling out the parasitic inductance occurring in the filter circuit 100, it was necessary to prepare and test coil components with different mutual inductances M. Therefore, by adopting the configuration described above in the coil component 10, different mutual inductances M can be generated simply by changing the connection path, and the number of coil components required for testing can be reduced.

[0031] Specifically, it will be described how the mutual inductance M can be changed by changing the connection path of the coil component 10. FIG. 4 is a schematic diagram for explaining the connection paths between the coil component 10 according to the first embodiment and the land electrodes 5a to 5e of the substrate. As shown in FIG. 4( a), the coil component 10 connects the external electrode 4a to the land electrode 5a, the external electrode 4b to the land electrode 5b, the external electrodes 4c and 4e to the land electrode 5c, the external electrode 4d to the land electrode 5d, and the external electrode 4f to the land electrode 5e. In the coil component 10, the land electrode 5c electrically connects the external electrode 4c to the external electrode 4e, and the external electrodes 4c and 4e serve as intermediate terminals T and are electrically connected to the capacitor C1. Note that FIG. 4( a) illustrates only the land electrodes 5a to 5e, and does not illustrate the substrate on which the land electrodes 5a to 5e are provided.

[0032] In the case of a connection path in which the external electrodes 4c, 4e serve as intermediate terminals T, a current flows through the path of the second conductor pattern 2b-external electrode 4c-land electrode 5c-external electrode 4e-fifth conductor pattern 3b, and the first coil L1 (first conductor 2) and the second coil L2 (second conductor 3) are magnetically coupled. In this case, when viewed in plan from the top surface of the coil component 10, the portion where a part of the first conductor pattern 2a and a part of the fourth conductor pattern 3a overlap is an effective magnetic coupling portion K.

[0033] Next, Fig. 4(b) illustrates a connection path of the coil component 10 that is different from the connection path of the coil component 10 shown in Fig. 4(a). Specifically, the connection path of the coil component 10 shown in Fig. 4(b) is a connection path that connects the coil component 10 to the land electrodes 5a to 5e of the substrate by rotating the coil component 10 180 degrees in a plane parallel to the substrate with respect to Fig. 4(a). As shown in Fig. 4(b), the coil component 10 connects the external electrode 4a to the land electrode 5b, the external electrode 4b to the land electrode 5a, the external electrodes 4d and 4f to the land electrode 5c, the external electrode 4e to the land electrode 5d, and the external electrode 4d to the land electrode 5e. In the coil component 10, the external electrode 4d is electrically connected to the external electrode 4f by the land electrode 5c, and the external electrodes 4d and 4f serve as intermediate terminals T and are electrically connected to the capacitor C1. In FIG. 4B, only the land electrodes 5a to 5e are shown, and the substrate on which the land electrodes 5a to 5e are provided is not shown.

[0034] In the case of a connection path in which the external electrodes 4d, 4f serve as intermediate terminals T, a current flows through the path of the third conductor pattern 2c-external electrode 4d-land electrode 5c-external electrode 4f-sixth conductor pattern 3c, and the first coil L1 (first conductor 2) and the second coil L2 (second conductor 3) are magnetically coupled. In this case, when viewed in plan from the top surface of the coil component 10, the portion where a part of the first conductor pattern 2a and a part of the fourth conductor pattern 3a overlap is an effective magnetic coupling portion K.

[0035] 4(a) and 4(b), the effective magnetic coupling portion K in the coil component 10 is the portion where a part of the first conductor pattern 2a and a part of the fourth conductor pattern 3a overlap. However, in the connection path shown in Fig. 4(a), the path from the magnetic coupling portion K to the external electrodes 4c and 4e, which are intermediate terminals T (the second conductor pattern 2b and the fifth conductor pattern 3b) becomes a parasitic inductance. In the connection path shown in Fig. 4(b), the path from the magnetic coupling portion K to the external electrodes 4d and 4f, which are intermediate terminals T (the third conductor pattern 2c and the sixth conductor pattern 3c) becomes a parasitic inductance.

[0036] 2(b) and 2(c), the length D1 of the second conductor pattern 2b and the fifth conductor pattern 3b is longer than the length D2 of the third conductor pattern 2c and the sixth conductor pattern 3c, and therefore the parasitic inductance of the second conductor pattern 2b and the fifth conductor pattern 3b is larger than the parasitic inductance of the third conductor pattern 2c and the sixth conductor pattern 3c. As a result, the mutual inductance M when the coil component 10 is connected to the land electrodes 5a to 5e via the connection path shown in Fig. 4(a) is larger than the mutual inductance M when the coil component 10 is connected to the land electrodes 5a to 5e via the connection path shown in Fig. 4(b) (the absolute value of the mutual inductance M is smaller).

[0037] A simulation of the mutual inductance M was performed when the coil component 10 was connected to the land electrodes 5a to 5e via the connection path shown in FIG. 4( a). The element size of the coil component 10 used in the simulation was 2.5 mm × 2.0 mm × 0.9 mm, the width of each conductor pattern was 0.2 mm, the distance between the second conductor pattern 2b and the fifth conductor pattern 3b in a top view was 0.6 mm, the length D1 was 0.5 mm, the length D2 was 1.3 mm, and the interlayer distance between the first coil L1 and the second coil L2 was 0.21 mm. As a result of the simulation, the value of the mutual inductance M was M = −1.15 nH. On the other hand, when the coil component 10 was connected to the land electrodes 5a to 5e via the connection path shown in FIG. 4( b), the simulated value of the mutual inductance M was M = −1.31 nH. The mutual inductance M can be varied by 0.15 nH (approximately 14%) simply by changing the connection path of the coil component 10.

[0038] Connection paths other than those shown in Figures 4(a) and 4(b) will also be described. Figure 5 is a schematic diagram for explaining another connection path between the coil component 10 according to the first embodiment and the land electrodes of the substrate. As shown in Figure 5(a), the coil component 10 connects the external electrode 4a to the land electrode 5a, the external electrode 4b to the land electrode 5b, the external electrodes 4c and 4e to the land electrode 5c, and the external electrodes 4d and 4f to the land electrode 5f. In the coil component 10, the land electrode 5c electrically connects the external electrode 4c to the external electrode 4e, thereby electrically connecting the external electrodes 4c and 4e to the capacitor C1 as intermediate terminals T, and the land electrode 5f electrically connects the external electrode 4d to the external electrode 4f.

[0039] In the case of the connection path shown in FIG. 5( a), a path of the third conductor pattern 2c-external electrode 4d-land electrode 5f-external electrode 4f-sixth conductor pattern 3c is added to the connection path shown in FIG. 4( a). The path flowing through the third conductor pattern 2c and the sixth conductor pattern 3c is further added as a positive inductance to the connection path shown in FIG. 4( a), thereby canceling out the negative component of the mutual inductance M. Furthermore, because the added path is shorter than the connection path shown in FIG. 4( a), current flows through the added path, and the positive inductance value of the added path becomes relatively large. Therefore, the simulated value of the mutual inductance M when the coil component 10 is connected to the land electrodes 5a to 5c and 5f via the connection path shown in FIG. 5( a) is M=+1.94 nH.

[0040] 5(b), the coil component 10 connects the external electrode 4a to the land electrode 5b, the external electrode 4b to the land electrode 5a, the external electrodes 4c and 4e to the land electrode 5f, and the external electrodes 4d and 4f to the land electrode 5c. In the coil component 10, the land electrode 5c electrically connects the external electrode 4d to the external electrode 4f, and thereby the external electrodes 4d and 4f serve as intermediate terminals T and are electrically connected to the capacitor C1, and the land electrode 5f electrically connects the external electrode 4c to the external electrode 4e.

[0041] In the case of the connection path shown in FIG. 5( b), a path from the second conductor pattern 2b to the external electrode 4c to the land electrode 5f to the external electrode 4e to the fifth conductor pattern 3b is added to the connection path shown in FIG. 4( b). The path through the second conductor pattern 2b and the fifth conductor pattern 3b is added as a positive inductance to the connection path shown in FIG. 4( b), thereby canceling out the negative component of the mutual inductance M. Because the added path is shorter than the connection path shown in FIG. 4( b), the amount of current flowing through it is also smaller than that of the connection path shown in FIG. 4( b), resulting in a relatively small positive inductance value. Therefore, the simulated value of the mutual inductance M when the coil component 10 is connected to the land electrodes 5a to 5c and 5f via the connection path shown in FIG. 5( b) is M = −0.83 nH.

[0042] Another connection path will also be described. Figure 6 is a schematic diagram for describing yet another connection path between the coil component 10 according to the first embodiment and the land electrodes of the substrate. As shown in Figure 6(a) , the coil component 10 has the external electrode 4a connected to the land electrode 5a, the external electrode 4b connected to the land electrode 5b, the external electrodes 4c and 4e connected to the land electrode 5c, the external electrodes 4d and 4f connected to the land electrode 5f, and the land electrode 5c and the land electrode 5f electrically connected by a wiring 6. In the coil component 10, the wiring 6 electrically connects the land electrode 5c to the land electrode 5f, so that the external electrodes 4c to 4f are electrically connected to the capacitor C1 as intermediate terminals T.

[0043] Fig. 6(b) is a circuit diagram of a filter circuit 100a including the coil component 10 mounted on a substrate via the connection path shown in Fig. 6(a). The filter circuit 100a is a circuit in which a coil L1a formed by the first conductor pattern 2a and the second conductor pattern 2b, a coil L1b formed by the first conductor pattern 2a and the third conductor pattern 2c, a coil L2a formed by the fourth conductor pattern 3a and the fifth conductor pattern 3b, and a coil L2b formed by the fourth conductor pattern 3a and the sixth conductor pattern 3c are electrically connected by wiring 6.

[0044] The simulated value of the mutual inductance M for the connection path shown in FIG. 6( a) is M = −1.21 nH. The simulated value of the mutual inductance M for a connection path in which the coil component 10 is rotated 180 degrees in a plane parallel to the substrate relative to the connection path shown in FIG. 6( a) is M = −1.41 nH. Note that, as shown in FIG. 6( a), the wiring 6 is formed with the same width of 1.1 mm as the land electrodes 5 c and 5 f, but this width may be narrower. For example, when the width of the wiring 6 is narrowed to 0.4 mm, which is approximately one-third the width, the simulated value of the mutual inductance M is M = −1.00 nH. In other words, the mutual inductance M can be increased by narrowing the width of the wiring 6.

[0045] <Embodiment 2> In embodiment 1, it was described that the first conductor 2 and the second conductor 3 included in the coil component 10 have a T-shape. In embodiment 2, a coil component including first conductors and second conductors of different shapes will be described in detail. FIG. 7 is a schematic diagram of a coil component 10A according to embodiment 2. Note that in the coil component 10A shown in embodiment 2, the same components as those in the coil component 10 according to embodiment 1 are designated by the same reference numerals and detailed description thereof will not be repeated. Furthermore, the coil component 10A shown in embodiment 2 can be applied to the filter circuit 100 according to embodiment 1 in place of the coil component 10 according to embodiment 1.

[0046] Coil component 10A includes two coils, a first conductor 21 that forms first coil L1 and a second conductor 31 that forms second coil L2, enclosed within insulator 1. The first coil L1 and second coil L2 are magnetically coupled to form a transformer. Fig. 7(a) is a diagram of first conductor 21 and second conductor 31 when viewed from the top surface of coil component 10A. Fig. 7(b) is a plan view of first conductor 21 formed on insulating substrate 1b, and Fig. 7(c) is a plan view of second conductor 31 formed on insulating substrate 1c. Coil component 10A is formed by stacking and pressure-bonding multiple insulating substrates, including insulating substrate 1b and insulating substrate 1c, and firing the stack, followed by baking external electrodes onto the side surfaces.

[0047] 7(b), the first conductor 21 is a conductor pattern formed on the insulating substrate 1b, combining a T-shape and an L-shape, and includes a first conductor pattern 21a, a second conductor pattern 21b, and a third conductor pattern 21c. The first conductor pattern 21a is drawn from the first side surface 12A of the insulator 1 and electrically connected to the external electrode 4a. The second conductor pattern 21b includes a conductor pattern 21b1 extending from an end of the first conductor pattern 21a toward the second side surface 12B, a conductor pattern 21b2 extending toward the first side surface 12A, and a conductor pattern 21b3 drawn from the second side surface 12B and electrically connected to the external electrode 4e. The third conductor pattern 21c extends from an end of the first conductor pattern 21a toward the third side surface 12C and is drawn from the third side surface 12C and electrically connected to the external electrode 4d.

[0048] The first conductor 21 has a T-shape formed by the first conductor pattern 21a, the conductor pattern 21b1, and the third conductor pattern 21c, and an L-shape formed by the conductor pattern 21b2 and the conductor pattern 21b3. The first conductor 21 has a conductor pattern 21b2 that folds back in the direction of the first side surface 12A on the second conductor pattern 21b. The second conductor pattern 21b is longer than the third conductor pattern 21c.

[0049] 7( c), the second conductor 31 is a conductor pattern formed on the insulating substrate 1c, combining a T-shape and an L-shape, and includes a fourth conductor pattern 31a, a fifth conductor pattern 31b, and a sixth conductor pattern 31c. The fourth conductor pattern 31a is drawn from the fourth side surface 12D of the insulator 1 and electrically connected to the external electrode 4b. The fifth conductor pattern 31b includes a conductor pattern 31b1 extending from an end of the fourth conductor pattern 31a toward the second side surface 12B, a conductor pattern 31b2 extending toward the fourth side surface 12D, and a conductor pattern 31b3 drawn from the second side surface 12B and electrically connected to the external electrode 4c. The sixth conductor pattern 31c extends from an end of the fourth conductor pattern 31a toward the third side surface 12C and is drawn from the third side surface 12C and electrically connected to the external electrode 4f.

[0050] The second conductor 31 has a T-shape formed by the fourth conductor pattern 31a, the conductor pattern 31b1, and the sixth conductor pattern 31c, and an L-shape formed by the conductor pattern 31b2 and the conductor pattern 31b3. The second conductor 31 has a conductor pattern 31b2 that is folded back in the direction of the fourth side surface 12D on the fifth conductor pattern 31b. The fifth conductor pattern 31b is longer than the sixth conductor pattern 31c.

[0051] In the coil component 10A, the second conductor pattern 21b includes a conductor pattern 21b2 that folds back toward the first side surface 12A, and the fifth conductor pattern 31b includes a conductor pattern 31b2 that folds back toward the fourth side surface 12D. Therefore, the conductor patterns 21b2 and 31b2 overlap in a plan view from the top surface. In other words, the coil component 10A has a portion where the second conductor pattern 21b and the fifth conductor pattern overlap. Therefore, magnetic coupling occurs in this portion of the coil component 10A, and the simulated value of the mutual inductance M for a connection path electrically connecting the external electrodes 4c and 4e is M = −1.24 nH. The mutual inductance M for the connection path shown in FIG. 7( a) is 0.09 nH smaller than that for the connection path shown in FIG. 4( a).

[0052] The coil component 10A may be configured to have an overlapping portion between the third conductor pattern 21c and the sixth conductor pattern 31c, rather than having an overlapping portion between the second conductor pattern 21b and the fifth conductor pattern 31b. Specifically, the third conductor pattern 21c includes a conductor pattern extending from an end of the first conductor pattern 21a in the direction of the third side face 12C, a conductor pattern extending in the direction of the first side face 12A, and a conductor pattern drawn from the third side face 12C to be electrically connected to the external electrode 4f. The sixth conductor pattern 31c includes a conductor pattern extending from an end of the fourth conductor pattern 31a in the direction of the third side face 12C, a conductor pattern extending in the direction of the fourth side face 12D, and a conductor pattern drawn from the third side face 12C to be electrically connected to the external electrode 4d.

[0053] <Embodiment 3> In embodiment 1, it was described that the coil component 10 has a value of mutual inductance M whether the connection path is the one shown in FIG. 4(a) or the connection path shown in FIG. 4(b). In embodiment 3, a coil component in which one connection path has a value of mutual inductance M and the value of mutual inductance M is 0 (zero) in the other connection path will be described in detail. FIG. 8 is a schematic diagram of a coil component 10B according to embodiment 3. Note that in the coil component 10B shown in embodiment 3, the same components as those in the coil component 10 according to embodiment 1 are designated by the same reference numerals and detailed description thereof will not be repeated. Furthermore, the coil component 10B shown in embodiment 3 can be applied to the filter circuit 100 according to embodiment 1 in place of the coil component 10 according to embodiment 1.

[0054] Coil component 10B includes two coils, a first conductor 22 that forms a first coil L1 and a second conductor 32 that forms a second coil L2, enclosed within insulator 1. The first coil L1 and the second coil L2 are magnetically coupled to form a transformer. Fig. 8(a) is a diagram of the first conductor 22 and the second conductor 32 when viewed from the top surface of coil component 10B. Fig. 8(b) is a plan view of the first conductor 22 formed on insulating substrate 1b, and Fig. 8(c) is a plan view of the second conductor 32 formed on insulating substrate 1c. Coil component 10B is formed by stacking and pressure-bonding multiple insulating substrates, including insulating substrate 1b and insulating substrate 1c, and firing the stack, followed by baking external electrodes onto the side surfaces.

[0055] 8(b), the first conductor 22 is a conductor pattern formed on the insulating substrate 1b by combining two L-shaped portions, and includes a first conductor pattern 22a, a second conductor pattern 22b, and a third conductor pattern 22c. The first conductor pattern 22a is drawn from the first side surface 12A of the insulator 1 and is electrically connected to the external electrode 4a. The second conductor pattern 22b extends from an end of the first conductor pattern 22a toward the second side surface 12B, is drawn from the second side surface 12B, and is electrically connected to the external electrode 4c. The third conductor pattern 22c extends from the middle of the first conductor pattern 22a toward the third side surface 12C, is drawn from the third side surface 12C, and is electrically connected to the external electrode 4f.

[0056] The first conductor 22 has a first conductor pattern 22a and a second conductor pattern 22b that form an L-shape, and a first conductor pattern 22a and a third conductor pattern 22c that form an L-shape. The second conductor pattern 22b is longer than the third conductor pattern 22c.

[0057] 8(c), the second conductor 32 is a conductor pattern formed on the insulating substrate 1c by combining two L-shaped portions, and includes a fourth conductor pattern 32a, a fifth conductor pattern 32b, and a sixth conductor pattern 32c. The fourth conductor pattern 32a is drawn from the fourth side surface 12D of the insulator 1 and electrically connected to the external electrode 4b. The fifth conductor pattern 32b extends from an end of the fourth conductor pattern 32a toward the second side surface 12B, is drawn from the second side surface 12B, and is electrically connected to the external electrode 4e. The sixth conductor pattern 32c extends from the middle of the fourth conductor pattern 32a toward the third side surface 12C, is drawn from the third side surface 12C, and is electrically connected to the external electrode 4d.

[0058] The second conductor 32 has a fourth conductor pattern 32 a and a fifth conductor pattern 32 b that form an L-shape, and a sixth conductor pattern 32 c that form an L-shape. The fifth conductor pattern 32 b is longer than the sixth conductor pattern 32 c.

[0059] Specifically, we will explain how changing the connection path of the coil component 10B can change the mutual inductance between M and 0 (zero). FIG. 9 is a schematic diagram illustrating the connection paths between the coil component 10B according to the third embodiment and the land electrodes 5a to 5e of the substrate. As shown in FIG. 9( a), the coil component 10B connects the external electrode 4a to the land electrode 5a, the external electrode 4b to the land electrode 5b, the external electrodes 4c and 4e to the land electrode 5c, the external electrode 4d to the land electrode 5d, and the external electrode 4f to the land electrode 5e. In the coil component 10B, the land electrode 5c electrically connects the external electrode 4c to the external electrode 4e, and the external electrodes 4c and 4e serve as intermediate terminals T, which are electrically connected to the capacitor C1. Note that FIG. 9( a) illustrates only the land electrodes 5a to 5e, and does not illustrate the substrate on which the land electrodes 5a to 5e are provided.

[0060] In the case of a connection path in which the external electrodes 4c, 4e serve as intermediate terminals T, a current flows through the path of the second conductor pattern 22b-external electrode 4c-land electrode 5c-external electrode 4e-fifth conductor pattern 32b, and the first coil L1 (first conductor 2) and the second coil L2 (second conductor 3) are magnetically coupled. In this case, in the coil component 10B, when viewed in plan from the top surface, the portion where a part of the first conductor pattern 22a and a part of the fourth conductor pattern 32a overlap is an effective magnetic coupling portion K.

[0061] Next, Figure 9(b) illustrates a connection path of the coil component 10B that is different from the connection path of the coil component 10B shown in Figure 9(a). Specifically, the connection path of the coil component 10B shown in Figure 9(b) is a connection path that connects the coil component 10B to the land electrodes 5a to 5e of the substrate by rotating the coil component 10B 180 degrees in a plane parallel to the substrate with respect to Figure 9(a). As shown in Figure 9(b), the coil component 10B connects the external electrode 4a to the land electrode 5b, the external electrode 4b to the land electrode 5a, the external electrodes 4d and 4f to the land electrode 5c, the external electrode 4e to the land electrode 5d, and the external electrode 4c to the land electrode 5e. In the coil component 10B, the external electrode 4d is electrically connected to the external electrode 4f via the land electrode 5c, and the external electrodes 4d and 4f serve as intermediate terminals T and are electrically connected to the capacitor C1. In FIG. 9B, only the land electrodes 5a to 5e are shown, and the substrate on which the land electrodes 5a to 5e are provided is not shown.

[0062] In the case of a connection path in which the external electrodes 4d and 4f serve as intermediate terminals T, a current flows through the path of the sixth conductor pattern 32c-external electrode 4d-land electrode 5c-external electrode 4f-third conductor pattern 22c, but when viewed from the top surface, no current flows through the portion where a part of the first conductor pattern 22a overlaps a part of the fourth conductor pattern 32a. In the connection path of the coil component 10B shown in FIG. 9(b), the portion where a part of the first conductor pattern 2a overlaps a part of the fourth conductor pattern 3a does not form an effective magnetic coupling portion K, and the current simply detours through the path I of the sixth conductor pattern 32c-external electrode 4d-land electrode 5c-external electrode 4f-third conductor pattern 22c. Therefore, in the connection path of the coil component 10B shown in FIG. 9(b), there is no effective magnetic coupling portion K, and the value of the mutual inductance M of the coil component 10B is 0 (zero).

[0063] As described above, in the coil component 10B, the second conductor pattern 22b extends from the end of the first conductor pattern 22a in the direction of the second side surface 12B, the third conductor pattern 22c extends from the middle of the first conductor pattern 22a in the direction of the third side surface 12C, the fifth conductor pattern 32b extends from the end of the fourth conductor pattern 32a in the direction of the second side surface 12B, and the sixth conductor pattern 32c extends from the middle of the fourth conductor pattern 32a in the direction of the third side surface 12C. However, in the coil component 10B, the second conductor pattern 22b may extend from the middle of the first conductor pattern 22a in the direction of the second side surface 12B, the third conductor pattern 22c may extend from an end of the first conductor pattern 22a in the direction of the third side surface 12C, the fifth conductor pattern 32b may extend from the middle of the fourth conductor pattern 32a in the direction of the second side surface 12B, and the sixth conductor pattern 32c may extend from the end of the fourth conductor pattern 32a in the direction of the third side surface 12C. In this way, by setting the value of the mutual inductance M of the path on one side to zero, it is possible to compare the noise suppression effects due to the mutual inductance M, or by forming multiple land electrodes on a substrate for mounting the coil component 10B, the mutual inductance M may be generated only in areas where the noise suppression effect is high, and the value of the mutual inductance M may be set to zero in other areas.

[0064] Fourth Embodiment In the first embodiment, the coil component 10 was described in which the first coil L1 is configured with a single layer of the first conductor 2 and the second coil L2 is configured with a single layer of the second conductor 3. In the fourth embodiment, a coil component will be described in which the first coil L1 is configured with multiple layers of the first conductor and the second coil L2 is configured with multiple layers of the second conductor. FIG. 10 is a schematic diagram of a coil component 10C according to the fourth embodiment. Note that in the coil component 10C shown in the fourth embodiment, the same components as those in the coil component 10 according to the first embodiment are designated by the same reference numerals and detailed description thereof will not be repeated. Furthermore, the coil component 10C shown in the fourth embodiment can be applied to the filter circuit 100 according to the first embodiment in place of the coil component 10 according to the first embodiment.

[0065] Coil component 10C includes two layers of first conductors 23 and 24 that form first coil L1 and two layers of second conductors 33 and 34 that form second coil L2, enclosed in insulator 1. First coil L1 and second coil L2 are magnetically coupled to form a transformer. Fig. 10(a) is a diagram of first conductors 23, 24 and second conductors 33, 34 when viewed from above from the top surface of coil component 10C. Fig. 10(b) is a side view of coil component 10C.

[0066] 10(b), the first conductors 23 and 24 are stacked in the Z direction and electrically connected by via conductors 51. The first conductor 23 includes a conductor pattern that is drawn from the first side surface 12A of the insulator 1 and electrically connected to the external electrode 4a, and a conductor pattern that is drawn from the third side surface 12C and electrically connected to the external electrode 4d. The first conductor 24 includes a conductor pattern that is drawn from the second side surface 12B and electrically connected to the external electrode 4c.

[0067] 10(b), the second conductors 33 and 34 are stacked in the Z direction and electrically connected by via conductors 52. The second conductor 33 includes a conductor pattern that is drawn from the fourth side surface 12D of the insulator 1 and electrically connected to the external electrode 4b, and a conductor pattern that is drawn from the third side surface 12C and electrically connected to the external electrode 4f. The second conductor 34 includes a conductor pattern that is drawn from the second side surface 12B and electrically connected to the external electrode 4e.

[0068] FIG. 11 is an exploded plan view showing the configuration of a coil component 10C according to a fourth embodiment. As shown in FIGS. 11( a) to 11(d), the coil component 10C includes an insulator 1 formed by stacking multiple insulating substrates, including insulating substrates 1a to 1d, on which coil conductors are formed. FIG. 11(a) is a plan view of a first conductor 23 formed on insulating substrate 1a, and FIG. 11(b) is a plan view of a first conductor 24 formed on insulating substrate 1b. FIG. 11(c) is a plan view of a second conductor 34 formed on insulating substrate 1c, and FIG. 11(d) is a plan view of a second conductor 33 formed on insulating substrate 1d. The coil component 10C is formed by stacking and pressure-bonding multiple insulating substrates, including insulating substrates 1a to 1d, and firing the stack, followed by baking external electrodes onto the side surfaces.

[0069] As shown in FIG. 11(a), conductor patterns 23a-23d of a first conductor 23 constituting a first coil L1 are formed on the insulating substrate 1a. The conductor pattern 23a is drawn out from the first side surface 12A of the insulator 1 shown in FIG. 10(a) and is electrically connected to the external electrode 4a. The conductor pattern 23b extends from the end of the conductor pattern 23a toward the second side surface 12B. The conductor pattern 23c extends from the end of the conductor pattern 23a toward the third side surface 12C and is drawn out from the third side surface 12C to be electrically connected to the external electrode 4d. The conductor pattern 23d extends from the end of the conductor pattern 23b toward the first side surface 12A. A connection portion 23A that connects to a via conductor 51 is provided at the end of the conductor pattern 23d.

[0070] As shown in FIG. 11(b), conductor patterns 24a to 24d of the first conductor 24 constituting the first coil L1 are formed on the insulating substrate 1b. The conductor pattern 24a extends toward the first side surface 12A of the insulator 1 shown in FIG. 10(a). A connection portion 24A that connects to the via conductor 51 is provided at the end of the conductor pattern 24a. The conductor pattern 24b extends from the end of the conductor pattern 24a toward the third side surface 12C. The conductor pattern 24c extends from the end of the conductor pattern 24b toward the fourth side surface 12D. The conductor pattern 24d extends from the end of the conductor pattern 24c toward the second side surface 12B and is drawn out from the second side surface 12B to be electrically connected to the external electrode 4c.

[0071] As shown in FIG. 11(c), conductor patterns 34a to 34d of the second conductor 34 constituting the second coil L2 are formed on the insulating substrate 1c. The conductor pattern 34a extends toward the fourth side surface 12D of the insulator 1 shown in FIG. 10(a). A connection portion 34A that connects to the via conductor 52 is provided at the end of the conductor pattern 34a. The conductor pattern 34b extends from the end of the conductor pattern 34a toward the third side surface 12C. The conductor pattern 34c extends from the end of the conductor pattern 34b toward the first side surface 12A. The conductor pattern 34d extends from the end of the conductor pattern 34c toward the second side surface 12B and is drawn out from the second side surface 12B to be electrically connected to the external electrode 4e.

[0072] As shown in FIG. 11(d), conductor patterns 33a to 33d of the second conductor 33 constituting the second coil L2 are formed on the insulating substrate 1d. The conductor pattern 33a is drawn out from the fourth side surface 12D of the insulator 1 shown in FIG. 10(a) and is electrically connected to the external electrode 4b. The conductor pattern 33b extends from the end of the conductor pattern 33a toward the second side surface 12B. The conductor pattern 33c extends from the end of the conductor pattern 33a toward the third side surface 12C and is drawn out from the third side surface 12C to be electrically connected to the external electrode 4f. The conductor pattern 33d extends from the end of the conductor pattern 33b toward the fourth side surface 12D. A connection portion 33A that connects to the via conductor 52 is provided at the end of the conductor pattern 33d.

[0073] 10A, in the coil device 10C, when viewed from above, the area where parts of the first conductors 23, 24 overlap with parts of the second conductors 33, 34 is greater than in the coil device 10, and therefore the effective magnetic coupling portions are increased. In the coil device 10C, the value of the mutual inductance M is reduced (the absolute value of the mutual inductance M is increased) due to the increased effective magnetic coupling portions.

[0074] Fifth Embodiment In the first embodiment, two coils, the first conductor 2 that forms the first coil L1 and the second conductor 3 that forms the second coil L2, are enclosed within the insulator 1, and the first conductor 2 and the second conductor 3 are each formed on one of a plurality of insulating substrates that form the insulator 1. In the fifth embodiment, the first conductor and the second conductor may be formed of a metal plate or a metal wire. FIG. 12 is a schematic diagram of a coil component 10D according to the fifth embodiment. Note that in the coil component 10D shown in the fifth embodiment, the same components as those in the coil component 10 according to the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof will not be repeated. Furthermore, the coil component 10D shown in the fifth embodiment can be applied to the filter circuit 100 according to the first embodiment in place of the coil component 10 according to the first embodiment.

[0075] Fig. 12(a) is a diagram of the first conductor 25 and the second conductor 35 when viewed from the top surface of the coil component 10D. Fig. 12(b) is a side view of the coil component 10D. The first conductor 25 is formed of a metal plate, integrally including a first conductor pattern 25a, a second conductor pattern 25b, and a third conductor pattern 25c that form the first coil L1, and lead wires 25a1, 25b1, and 25c1 that extend from the housing 1A. The second conductor 35 is formed of a metal plate, integrally including a fourth conductor pattern 35a, a fifth conductor pattern 35b, and a sixth conductor pattern 35c that form the second coil L2, and lead wires 35a1, 35b1, and 35c1 that extend from the housing 1A.

[0076] Coil component 10D includes two coils, a part of first conductor 25 that becomes first coil L1 and a part of second conductor 35 that becomes second coil L2, within housing 1A, and first coil L1 and second coil L2 are magnetically coupled to form a transformer. In coil component 10D, first coil L1 and second coil L2, which are formed from conductors, are fixed with the mold resin of housing 1A at an overlapping position, and lead wires 25a1, 25b1, 25c1, 35a1, 35b1, and 35c1 drawn from the side surface of housing 1A are bent along the side surface of housing 1A. Furthermore, in coil component 10D, ends of lead wires 25a1, 25b1, 25c1, 35a1, 35b1, and 35c1 are bent toward the bottom surface of housing 1A to form external electrodes 25a2, 25b2, 25c2, 35a2, 35b2, and 35c2 for electrical connection to land electrodes 5a to 5e. Note that external electrode 25a2 corresponds to external electrode 4a of coil component 10, external electrode 25b2 corresponds to external electrode 4c of coil component 10, external electrode 25c2 corresponds to external electrode 4d of coil component 10, external electrode 35a2 corresponds to external electrode 4b of coil component 10, external electrode 35b2 corresponds to external electrode 4e of coil component 10, and external electrode 35c2 corresponds to external electrode 4f of coil component 10, respectively.

[0077] 12(a), the housing 1A has side surfaces on the short sides (first side surface 12A and fourth side surface 12D) and side surfaces on the long sides (second side surface 12B and third side surface 12C). Of the positions at which the conductor pattern is drawn on the second side surface 12B, the side closer to the first side surface 12A is defined as a first position, and the side closer to the fourth side surface 12D is defined as a second position. Of the positions at which the conductor pattern is drawn on the third side surface 12C, the side closer to the first side surface 12A is defined as a third position, and the side closer to the fourth side surface 12D is defined as a fourth position.

[0078] As shown in Figures 12(a) and 12(b), the first conductor 25 includes a first conductor pattern 25a, a second conductor pattern 25b, and a third conductor pattern 25c, which are T-shaped conductor patterns. The first conductor pattern 25a is drawn from the first side surface 12A of the housing 1A and leads to a drawn-out wire 25a1 and an external electrode 25a2. The second conductor pattern 25b extends from an end of the first conductor pattern 25a toward the second side surface 12B, is drawn from a second position on the second side surface 12B, and leads to a drawn-out wire 25b1 and an external electrode 25b2. The third conductor pattern 25c extends from an end of the first conductor pattern 25a toward the third side surface 12C, is drawn from a fourth position on the third side surface 12C, and leads to a drawn-out wire 25c1 and an external electrode 25c2. The second conductor pattern 25b is longer than the third conductor pattern 25c.

[0079] As shown in Figures 12(a) and 12(b), the second conductor 35 includes a fourth conductor pattern 35a, a fifth conductor pattern 35b, and a sixth conductor pattern 35c, which are T-shaped conductor patterns. The fourth conductor pattern 35a is drawn out from the fourth side surface 12D of the housing 1A and leads to a drawn-out wire 35a1 and an external electrode 35a2. The fifth conductor pattern 35b extends from an end of the fourth conductor pattern 35a toward the second side surface 12B, is drawn out from a first position on the second side surface 12B, and leads to a drawn-out wire 35b1 and an external electrode 35b2. The sixth conductor pattern 35c extends from an end of the fourth conductor pattern 35a toward the third side surface 12C, is drawn out from a third position on the third side surface 12C, and leads to a drawn-out wire 35c1 and an external electrode 35c2. The fifth conductor pattern 35b is longer than the sixth conductor pattern 35c.

[0080] In the coil device 10D, the first conductor 25 and the second conductor 35 are formed from a metal plate or metal wire, which allows the thickness of the first conductor 25 and the second conductor 35 to be increased, thereby reducing the DC resistance and increasing the rated current. In the coil device 10D, the first conductor 25 and the second conductor 35 are described as including a T-shaped conductor pattern, but the configurations described in the second to fourth embodiments may also be employed. Also, FIG. 12 shows an example in which the external electrodes 25a2, 25b2, etc. are linear extensions of the lead wires 25a1, 25b1, etc. However, the shapes of the external electrodes 25a2, 25b2, etc. are not limited thereto, and the external electrodes 25a2, 25b2, etc. may be partially folded toward the underside of the housing 1A so as to be parallel to the land electrodes 5a, 5b, etc.

[0081] (Modifications) (1) The housings of the coil components 10, 10A to 10D have been described as being made of, for example, an insulating material primarily composed of borosilicate glass, or an insulating resin such as alumina, zirconia, or polyimide resin. However, the housings of the coil components 10, 10A to 10D may be made of either a magnetic or dielectric material. Examples of magnetic materials used for the housings of the coil components 10, 10A to 10D include ferrite. Examples of dielectric materials used for the housings of the coil components 10, 10A to 10D include titanium oxide and barium oxide. Insulating materials containing these magnetic or dielectric materials may also be used. Note that using a dielectric for the housings of the coil components 10, 10A to 10D prevents magnetic saturation, allowing a large current to flow through the coil components 10, 10A to 10D.

[0082] In the coil components 10, 10A to 10D, when viewed in plan from the top surface, the second conductor patterns 2b, 21b to 25b are longer than the third conductor patterns 2c, 21c to 25c, and the fifth conductor patterns 3b, 31b to 35b are longer than the sixth conductor patterns 3c, 31c to 35c. However, the coil components are not limited to this, and the second conductor patterns 2b, 21b to 25b may be shorter in length than the third conductor patterns 2c, 21c to 25c, or the fifth conductor patterns 3b, 31b to 35b may be shorter in length than the sixth conductor patterns 3c, 31c to 35c.

[0083] The value of mutual inductance M of the coil components 10, 10A to 10D can be changed by changing the ratio of the lengths of the second conductor patterns 2b, 21b to 25b and the third conductor patterns 2c, 21c to 25c when viewed in a plane from the top surface side, and by changing the ratio of the lengths of the fifth conductor patterns 3b, 31b to 35b and the sixth conductor patterns 3c, 31c to 35c.

[0084] In the coil components 10, 10A to 10D, the positions of the external electrodes 4c (second positions) and 4e (first positions) on the second side surface 12B and the positions of the external electrodes 4d (fourth positions) and 4f (third positions) on the third side surface 12C have been described as being point-symmetrical when viewed from the direction of the first main surface 11A. However, this is not limiting, and by devising the arrangement of the land electrodes on the substrate, the positions of the external electrodes 4c (second positions) and 4e (first positions) and the positions of the external electrodes 4d (fourth positions) and 4f (third positions) do not have to be point-symmetrical when viewed from the direction of the first main surface 11A.

[0085] In the coil components 10, 10A to 10C, when the external electrodes 4c to 4f are formed not only on the side surfaces of the insulator 1 but also on the top and bottom surfaces, even if the coil components are rotated 180 degrees in a plane parallel to the substrate, they do not need to be connected to the land electrodes of the substrate, and the coil components themselves can be turned over and connected to the land electrodes.

[0086] <Aspects> (1) A coil component according to the present disclosure includes a housing having a pair of first and second main surfaces opposing each other and four side surfaces connecting the first and second main surfaces, a first coil disposed inside the housing, and a second coil magnetically coupled to the first coil, wherein the first coil includes: a first conductor pattern drawn from a first side surface of the housing, a second conductor pattern extending from the first conductor pattern in a direction toward the second side surface, and a third conductor pattern extending from the first conductor pattern in a direction toward a third side surface opposite the second side surface, wherein the second coil includes: a fourth conductor pattern drawn from a fourth side surface opposite the first side surface of the housing, a fifth conductor pattern extending from the second conductor pattern in the direction toward the second side surface, and a sixth conductor pattern extending from the second conductor pattern in the direction toward the third side surface, wherein the second conductor pattern is drawn from a position on the second side surface closer to the fourth side surface than the fifth conductor pattern, The third conductor pattern is drawn out from a position on the third side surface that is closer to the fourth side surface than the sixth conductor pattern.

[0087] (2) In the coil component described in (1), the second conductor pattern has a different length from the third conductor pattern when viewed from the direction of the first principal surface, and the fifth conductor pattern has a different length from the sixth conductor pattern when viewed from the direction of the first principal surface.

[0088] (3) In the coil component described in (2), the first conductor pattern and the fourth conductor pattern are arranged on the second side surface side when viewed from the direction of the first main surface.

[0089] (4) In the coil component described in any one of (1) to (3), of the positions at which the conductor patterns are drawn on the second side surface, the side closer to the first side surface is defined as a first position and the side closer to the fourth side surface is defined as a second position; of the positions at which the conductor patterns are drawn on the third side surface, the side closer to the first side surface is defined as a third position and the side closer to the fourth side surface is defined as a fourth position; the second conductor pattern is drawn from the second position; the third conductor pattern is drawn from the fourth position; the fifth conductor pattern is drawn from the first position; and the sixth conductor pattern is drawn from the third position.

[0090] (5) In the coil component described in any one of (1) to (3), of the positions at which the conductor patterns are drawn on the second side surface, the side closer to the first side surface is defined as a first position and the side closer to the fourth side surface is defined as a second position; of the positions at which the conductor patterns are drawn on the third side surface, the side closer to the first side surface is defined as a third position and the side closer to the fourth side surface is defined as a fourth position; the second conductor pattern is drawn from the first position, the third conductor pattern is drawn from the fourth position, the fifth conductor pattern is drawn from the second position, and the sixth conductor pattern is drawn from the third position; or the second conductor pattern is drawn from the second position, the third conductor pattern is drawn from the third position, the fifth conductor pattern is drawn from the first position, and the sixth conductor pattern is drawn from the fourth position.

[0091] (6) The coil component described in (5) has an overlapping portion between the second conductor pattern and the fifth conductor pattern when viewed from the first main surface direction, when the second conductor pattern is drawn out from the first position and the fifth conductor pattern is drawn out from the second position, or has an overlapping portion between the third conductor pattern and the sixth conductor pattern when viewed from the first main surface direction, when the third conductor pattern is drawn out from the third position and the sixth conductor pattern is drawn out from the fourth position.

[0092] (7) In the coil component described in any one of (4) to (6), the first position and the second position on the second side surface and the third position and the fourth position on the third side surface are located in point-symmetric positions when viewed from the direction of the first main surface.

[0093] (8) In the coil component according to any one of (1) to (7), the second conductor pattern, the third conductor pattern, the fifth conductor pattern, and the sixth conductor pattern are electrically connected by wiring.

[0094] (9) In the coil component according to any one of (1) to (8), the housing is made of a dielectric material.

[0095] (10) The coil component described in any one of (1) to (9) is characterized in that the housing is an insulator formed by stacking a plurality of insulating substrates, each having a plurality of conductor patterns formed thereon, in a direction from the second main surface to the first main surface, and has a first external electrode electrically connected to the first conductor pattern on a first side surface, a second external electrode electrically connected to the second conductor pattern on a second side surface, a third external electrode electrically connected to the third conductor pattern on a third side surface, a fourth external electrode electrically connected to the fourth conductor pattern on a fourth side surface, a fifth external electrode electrically connected to the fifth conductor pattern on the second side surface, and a sixth external electrode electrically connected to the sixth conductor pattern on the third side surface.

[0096] (11) In the coil component according to (10), the first coil and the second coil are configured by electrically connecting a plurality of conductor patterns stacked inside the housing.

[0097] (12) In the coil component according to any one of (1) to (11), the first coil and the second coil are formed from a metal plate or a metal wire, and a portion of the metal plate or the metal wire is drawn out from a side surface of the housing.

[0098] (13) A filter circuit according to the present disclosure includes the coil component according to any one of (1) to (12) above, and a capacitor electrically connected to the second conductor pattern and the fifth conductor pattern of the coil component, or electrically connected to the third conductor pattern and the sixth conductor pattern of the coil component.

[0099] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0100] 1 Insulator, 2, 21 to 25 First conductor, 3, 31 to 35 Second conductor, 4a to 4f External electrode, 5a to 5f Land electrode, 6 Wiring, 10, 10A to 100 Coil component, 11A First main surface, 11B Second main surface, 12A First side surface, 12B Second side surface, 12C Third side surface, 12D Fourth side surface, 51, 52 Via conductor, 100, 100a Filter circuit.

Claims

1. A housing having a pair of first and second main surfaces facing each other and four side surfaces connecting between the first main surface and the second main surface; A first coil disposed inside the housing; A second coil magnetically coupled to the first coil, comprising: The first coil includes: A first conductor pattern drawn out from the first side surface side of the housing; A second conductor pattern extending from the first conductor pattern in the direction of the second side surface; A third conductor pattern extending from the first conductor pattern in the direction of the third side surface facing the second side surface; The second coil includes: A fourth conductor pattern drawn out from the fourth side surface side facing the first side surface of the housing; A fifth conductor pattern extending from the second conductor pattern in the direction of the second side surface; A sixth conductor pattern extending from the second conductor pattern in the direction of the third side surface; The second conductor pattern is drawn out from a position on the second side surface closer to the fourth side surface than the fifth conductor pattern; The third conductor pattern is drawn out from a position on the third side surface closer to the fourth side surface than the sixth conductor pattern. A coil component.

2. The length of the second conductor pattern is different from that of the third conductor pattern when viewed from the direction of the first main surface; The length of the fifth conductor pattern is different from that of the sixth conductor pattern when viewed from the direction of the first main surface. The coil component according to claim 1.

3. The first conductor pattern and the fourth conductor pattern are disposed on the second side surface side when viewed from the direction of the first main surface. The coil component according to claim 2.

4. Among the positions on the second side surface where the conductor pattern is drawn out, the side closer to the first side surface is defined as the first position, and the side closer to the fourth side surface is defined as the second position; Among the positions on the third side surface where the conductor pattern is drawn out, the side closer to the first side surface is defined as the third position, and the side closer to the fourth side surface is defined as the fourth position; The second conductor pattern is drawn out from the second position; The third conductor pattern is drawn out from the fourth position; The fifth conductor pattern is drawn out from the first position; The sixth conductor pattern is drawn out from the third position. The coil component according to claim 1.

5. Among the positions on the second side surface where the conductor pattern is drawn out, the side closer to the first side surface is defined as the first position, and the side closer to the fourth side surface is defined as the second position; Among the positions on the third side surface where the conductor pattern is drawn out, the side closer to the first side surface is defined as the third position, and the side closer to the fourth side surface is defined as the fourth position. The second conductor pattern is drawn out from the first position, the third conductor pattern is drawn out from the fourth position, the fifth conductor pattern is drawn out from the second position, and the sixth conductor pattern is drawn out from the third position. Or, the second conductor pattern is drawn out from the second position, the third conductor pattern is drawn out from the third position, the fifth conductor pattern is drawn out from the first position, and the sixth conductor pattern is drawn out from the fourth position. The coil component according to claim 1.

6. When the second conductor pattern is drawn out from the first position and the fifth conductor pattern is drawn out from the second position, there is a portion where the second conductor pattern and the fifth conductor pattern overlap when viewed from the direction of the first main surface. Or, when the third conductor pattern is drawn out from the third position and the sixth conductor pattern is drawn out from the fourth position, there is a portion where the third conductor pattern and the sixth conductor pattern overlap when viewed from the direction of the first main surface. The coil component according to claim 5.

7. The first position and the second position on the second side surface and the third position and the fourth position on the third side surface are in point-symmetrical positions when viewed from the direction of the first main surface. The coil component according to claim 4.

8. The second conductor pattern, the third conductor pattern, the fifth conductor pattern, and the sixth conductor pattern are electrically connected by wiring. The coil component according to claim 1.

9. The housing is made of a dielectric material. The coil component according to claim 1.

10. The housing is an insulator formed by laminating a plurality of insulating substrates having a plurality of conductor patterns formed thereon in the direction from the second main surface to the first main surface. On the first side surface, there is a first external electrode electrically connected to the first conductor pattern. On the second side surface, there is a second external electrode electrically connected to the second conductor pattern. On the third side surface, there is a third external electrode electrically connected to the third conductor pattern. On the fourth side surface, there is a fourth external electrode electrically connected to the fourth conductor pattern. On the second side surface, there is a fifth external electrode electrically connected to the fifth conductor pattern. The coil component according to any one of claims 1 to 9, having, on the third side surface, a sixth external electrode that is electrically connected to the sixth conductor pattern.

11. The coil component according to claim 10, wherein the first coil and the second coil are configured by electrically connecting a plurality of conductor patterns laminated inside the housing.

12. The coil component according to any one of claims 1 to 9, wherein the first coil and the second coil are formed from a metal plate or a metal wire, and a part of the metal plate or the metal wire is drawn out from a side surface of the housing.

13. The coil component according to any one of claims 1 to 9, and a filter circuit including a capacitor that is electrically connected to the second conductor pattern and the fifth conductor pattern of the coil component, or a capacitor that is electrically connected to the third conductor pattern and the sixth conductor pattern of the coil component.