Coil component and circuit device including same

Abstract

The present disclosure provides: a coil component that, with a simple structure, can constitute a coil having two or more turns when mounted on a substrate; and a circuit device including the coil component. A coil component (1) according to the present disclosure comprises a housing (4), a coil (L1) having a coil part (2a) that is disposed inside the housing (4) and is disposed substantially parallel to a main surface (40A), and a coil (L2) having a coil part (3a) that is disposed inside the housing (4) so that the opening of the coil (L2) overlaps the opening of the coil (L1) when viewed from the direction of the main surface (40A). The coil (L1) has a lead wire (2b) and a lead wire (2d) that are connected to the coil part (2a), the lead wires (2b, 2d) being led out from the side-surface (41) side of the housing (4) and being bent along the side-surface (41) side. The coil (L2) has a lead wire (3b) and a lead wire (3d) that are connected to the coil part (3a), the lead wires (3b, 3d) being led out from the side-surface (44) side adjacent to the side surface (41) and being bent along the side-surface (44) side.

Description

Coil components and circuit devices including the same

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

[0002] Various coil component structures have been proposed. For example, the coil component disclosed in Japanese Patent Laid-Open No. 2004-296630 (Patent Document 1) has a structure in which a coil formed by punching and bending a metal plate is embedded inside a magnetic body. Furthermore, for example, the coil component disclosed in Japanese Patent Laid-Open No. 2019-016642 (Patent Document 2) has a structure in which multiple ceramic substrates on which a metal paste is printed are stacked and fired.

[0003] JP 2004-296630 A JP 2019-016642 A

[0004] However, in the coil component disclosed in JP 2004-296630 A (Patent Document 1), in order to configure a coil with two or more turns to increase inductance, it is necessary to bend the metal plate so that the openings of the two coils overlap. When the metal plate is bent so that the openings of the two coils overlap, a portion where the metal plate is bent 180 degrees is formed, and the metal plate in that portion becomes thin, which may generate heat when a large current is passed through it.

[0005] In addition, in the coil component disclosed in JP 2019-016642 A (Patent Document 2), since the coil is formed by printing a metal paste on a ceramic substrate, it is difficult to form a thick coil. Furthermore, in this coil component, to form a coil with two or more turns, it is necessary to connect the coils formed on different layers with via conductors or the like provided between the layers.

[0006] Therefore, an object of the present disclosure is to provide a coil component that has a simple structure and can form a coil with two or more turns when mounted on a substrate, and a circuit device that includes the same.

[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, i.e., a first side surface, a second side surface, a third side surface, and a fourth side surface, connecting the first and second main surfaces; a first coil disposed inside the housing and having a first coil portion disposed substantially parallel to the first main surface; and a second coil disposed inside the housing such that an opening of the first coil overlaps an opening of the second coil when viewed from the direction of the first main surface. The first coil has first and second lead wires connected to the first coil portion, drawn from the first side surface of the housing and bent along the first side surface, and the second coil has third and fourth lead wires connected to the second coil portion, drawn from a second side surface adjacent to the first side surface and bent along the second side surface.

[0008] A circuit device according to an embodiment of the present disclosure includes the coil component described above and a circuit board on which the coil component is mounted, the circuit board including a first electrode electrically connecting the first lead wire, a second electrode electrically connecting the second lead wire and the third lead wire, and a third electrode connected to the fourth lead wire.

[0009] According to one embodiment of the present disclosure, the first coil has a first lead wire and a second lead wire connected to the first coil section, drawn out from the first side surface of the housing and bent along the first side surface, and the second coil has a third lead wire and a fourth lead wire connected to the second coil section, drawn out from the second side surface adjacent to the first side surface and bent along the second side surface, so that a two-turn coil can be formed by electrically connecting the second lead wire and the third lead wire with a substrate.

[0010] 1 is a perspective view of a circuit device according to embodiment 1. FIG. 2 is a plan view and a side view of a coil component according to embodiment 1. FIG. 3 is a circuit diagram of the circuit device according to embodiment 1. FIG. 4 is a perspective view of a circuit device according to a modified example of embodiment 1. FIG. 5 is a plan view and a side view of a coil component according to a modified example of embodiment 1. FIG. 6 is a perspective view of a circuit device according to embodiment 2. FIG. 7 is an example of a circuit diagram of a circuit device according to embodiment 2. FIG. 8 is a perspective view of a circuit device according to a modified example of embodiment 2. FIG. 9 is a plan view and a side view of a coil component according to a modified example of embodiment 2. FIG. 10 is a perspective view of a circuit device according to embodiment 3. FIG. 11 is an exploded plan view of the coil component according to embodiment 3. FIG. 12 is a circuit diagram of a circuit device according to embodiment 3.

[0011] Hereinafter, a coil component according to an embodiment of the present invention and a circuit device including the coil component will be described with reference to the drawings.

[0012] First Embodiment First, a coil component according to a first embodiment and a circuit device including the same will be described with reference to the drawings. Fig. 1 is a perspective view of a circuit device 100 according to the first embodiment. Fig. 2 is a plan view and a side view of the coil component 1 according to the first embodiment. Fig. 3 is a circuit diagram of the circuit device 100 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 left-right direction of the coil component 1, the Y-axis direction represents the front-rear direction of the coil component 1, and the Z-axis direction represents the up-down direction of the coil component 1, respectively.

[0013] The circuit device 100 includes a coil component 1 and a substrate 10 on which the coil component 1 is mounted. The coil component 1 includes two coils, and by mounting the coil component 1 on the substrate 10, a two-turn coil can be formed.

[0014] The coil component 1 includes a coil portion 2a (first coil portion) and a coil portion 3a (second coil portion) in a housing 4. The coil portion 2a has a lead wire 2b (first lead wire) connected to one end and a lead wire 2d (second lead wire) connected to the other end. The coil portion 2a and the lead wires 2b and 2d are collectively referred to as a coil L1 (first coil). The coil portion 3a has a lead wire 3b (third lead wire) connected to one end and a lead wire 3d (fourth lead wire) connected to the other end. The coil portion 3a and the lead wires 3b and 3d are collectively referred to as a coil L2 (second coil). Note that the coil portion 2a may be referred to as coil L1, and the coil portion 3a may be referred to as coil L2.

[0015] The coil portion 2a and the lead wires 2b, 2d are formed of a single conductor, for example, a metal plate or metal wire made of copper or an alloy of copper and other metals. Similarly, the coil portion 3a and the lead wires 3b, 3d are also formed of a single conductor. The coils L1 and L2, formed from metal plates, are covered with an insulating material (not shown). Specifically, the insulating material covering the coils L1 and L2 is a resin such as polyimide or epoxy. Note that the insulating material does not need to cover all surfaces of the coils L1 and L2. To prevent contact between the coils L1 and L2, it is sufficient that an insulating material is provided on at least one of the opposing surfaces of the coils L1 and L2.

[0016] The coil portion 2a has a U-shaped opening when viewed from the direction of the main surface 40A (first main surface), and is disposed inside the housing 4 substantially parallel to the main surface 40A. The coil portion 2a is a single-turn coil. The lead wires 2b and 2d are drawn out from the side surface 41 (first side surface) of the housing 4, bent along the side surface 41, and extended toward the main surface 40B (second main surface). The lead wire 2b shown in FIG. 1 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end 2c. The lead wire 2d extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end 2e. When the coil component 1 is mounted on a substrate 10, the end 2c is electrically connected to an electrode 11 (first electrode) on the substrate 10, and the end 2e is electrically connected to an electrode 12 (second electrode) on the substrate 10. Here, "lead-out wires 2b and 2d being bent along the side surface 41" does not necessarily mean that lead-out wires 2b and 2d are bent in a state where they are in contact with the side surface 41, but may mean that lead-out wires 2b and 2d are bent in the direction of the side surface 41. For example, lead-out wires 2b and 2d may be bent in a state where they are parallel to the side surface 41, and lead-out wires 2b and 2d may be arranged parallel to the side surface 41.

[0017] The coil portion 3a has a U-shaped opening when viewed from the direction of the main surface 40A, and is disposed above the coil portion 2a inside the housing 4, approximately parallel to the main surface 40A. The coil portion 3a is a single-turn coil. The lead wires 3b and 3d are drawn out from a side surface 44 (second side surface) adjacent to the side surface 41 of the housing 4, bent along the side surface 42, and extended toward the main surface 40B. The lead wire 3b shown in FIG. 1 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 3c. The lead wire 3d extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 3e. When the coil component 1 is mounted on the substrate 10, the end portion 3c is electrically connected to an electrode 12 on the substrate 10, and the end portion 3e is electrically connected to an electrode 13 (third electrode) on the substrate 10. Here, "lead-out wires 3b and 3d being bent along the side surface 42" does not necessarily mean that lead-out wires 3b and 3d are bent in a state where they are in contact with the side surface 42, but may mean that lead-out wires 3b and 3d are bent in the direction of the side surface 42. For example, lead-out wires 3b and 3d may be bent in a state where they are parallel to the side surface 42, and lead-out wires 3b and 3d may be arranged parallel to the side surface 42.

[0018] The ends 2e and 3c are electrically connected by an electrode 12 on the substrate 10. By connecting the ends 2e and 3c with the electrode 12, the coil L1 and the coil L2 are connected in series, and a two-turn coil is formed so that the opening of the coil L1 and the opening of the coil L2 overlap when viewed from the direction of the main surface 40A. The leads 2d and 3b, which are electrically connected by the same electrode 12, are drawn out near the corner between the side surface 41 and the side surface 44. This shortens the connection distance of the leads 2d and 3b, thereby reducing the influence of variations in inductance value due to the substrate 10 and heat generation at the electrode 12. Here, the lead-out position of at least the lead-out line 2d of the lead-out lines 2b and 2d is closer to the side surface 44 than to the side surface 43 adjacent to the side surface 41, and the lead-out position of at least the lead-out line 3b of the lead-out lines 3b and 3d is closer to the side surface 41 than to the side surface 42 adjacent to the side surface 44. The positions at which the lead wires 2b and 2d are arranged within the plane of the side surface 41 (first side surface) are not particularly limited, and the lead wires 2b (first lead wire) and 2d (second lead wire) may be arranged in a portion of the side surface 41 close to the side surface 43 (fourth side surface). The same applies to the lead wires 3b (third lead wire) and 3d (fourth lead wire).

[0019] When the electrode 11 of the coil L1 is connected to a power source, a current flows from the lead wire 2b to the coil portion 2a, and the current flows clockwise through the coil portion 2a as viewed from the main surface 40A. The current that flows through the coil portion 2a then flows through the lead wire 2d, the electrode 12, and the lead wire 3b. For the coil L2, a current flows from the lead wire 3b to the coil portion 3a, and the current flows clockwise through the coil portion 3a as viewed from the main surface 40A. Therefore, a magnetic field is generated in the coils L1 and L2 in the direction from the main surface 40A to the main surface 40B (-Z direction). Because the coil portions 2a and 3a are arranged so as to overlap as viewed from the main surface 40A, the coils L1 and L2 are magnetically coupled. Here, the opening of the coil L1 is defined as the portion surrounded by the three sides of the coil portion 2a and the one side of the coil portion 3a as viewed from the main surface 40A. Similarly, the opening of coil L2 is defined as the portion surrounded by three sides of coil portion 3a and one side of coil portion 2a when viewed from the direction of main surface 40A. While Fig. 2(a) shows an example in which the opening of coil L1 and the opening of coil L2 almost overlap, the openings may be offset as long as they are within the range of magnetic field coupling, and it is sufficient that 50% or more of one opening overlaps.

[0020] Furthermore, when capacitors C1 to C3 are connected to electrodes 11 to 13, respectively, circuit device 100 can easily configure a high-order filter circuit as shown in Fig. 3. Compared to configuring a high-order filter circuit by mounting multiple coils on substrate 10, circuit device 100 shown in Fig. 3 can save space, and the reduced number of components also increases the reliability of circuit device 100.

[0021] The housing 4 fixes the relative positions of the coil L1 and the coil L2 and is made of, for example, molded resin. Specifically, the molded resin may be an epoxy resin with silica filler, a silicone resin, a liquid crystal polymer, or various resins containing a metallic magnetic material. The housing 4 has a side surface 41 (first side surface) and a side surface 42 (third side surface) facing each other, with the side surface closer to the lead wire 2b designated as side surface 43 (fourth side surface) and the side surface closer to the lead wire 2d designated as side surface 44 (second side surface). While FIG. 1 depicts a rectangular parallelepiped shape, the side surfaces may be inclined as long as the second main surface, which serves as the mounting surface, and the coil surface are substantially parallel. For example, the housing 4 may be trapezoidal, with the second main surface having a larger area than the first main surface. While FIG. 1 illustrates an example in which the lead wires 2b and 2d are provided on the outside of the side surfaces of the housing 4, the lead wires 2b and 2d may be provided on the inside of the housing 4, or only the ends 2c and 2e connected to the substrate 10 may be provided on the outside of the housing 4.

[0022] As shown in FIG. 2( b), in the coil component 1, the lead wire 3b is routed with a gap from the side surface 44 of the housing 4, but the lead wire 3b may be routed directly along the side surface 44. Similarly, the lead wire 3d may be routed directly along the side surface 44. Similarly, the lead wires 2b and 2d may be routed directly along the side surface 41. Note that the coil component 1 is easy to manufacture and inexpensive because it is simply processed by bending a metal plate and there is no connection between the coil portion 2a and the coil portion 3a. Specifically, the size of the coil component 1 is, for example, 1 to 20 mm square, which is the size of a typical electronic component, and the allowable current of the coil component 1 is, for example, 1 to 20 A. Furthermore, in the coil component 1, the thickness of the metal plate is, for example, 0.1 to 0.5 mm, and the width between the coil L1 and the coil L2 is 0.2 to 0.4 mm. Furthermore, in the coil component 1, the coil portions 2a and 3a are both shown as having a linear shape, but because current concentration is likely to occur at the corners of the coil and stress concentration is likely to occur at the corners during processing, the corners of the coil may be rounded. For example, the shape of the coil portion 2a may be semicircular, extending from the vicinity of the side surface 43 to the vicinity of the side surface 42 and reaching the vicinity of the side surface 44. In this way, the shapes of the coil portions 2a and 3a are referred to as U-shaped, and include not only linear shapes but also rounded curved shapes.

[0023] (Modification) As shown in FIG. 2( a), coil component 1 has a U-shape when viewed from the direction of main surface 40A, with lead wires 2b and 2d extending from side surface 41 at positions spaced apart, and lead wires 3b and 3d extending from side surface 44 at positions spaced apart. However, coil component 1 may have lead wires extending from the side surface close to each other. FIG. 4 is a perspective view of a circuit device 100a according to a modification of embodiment 1. FIG. 5 is a plan view and a side view of coil component 1a according to a modification of embodiment 1. Note that in circuit device 100a and coil component 1a shown in the modification of embodiment 1, the same reference numerals are used for the same components as circuit device 100 and coil component 1 according to embodiment 1, and detailed description thereof will not be repeated.

[0024] The coil component 1a includes a coil portion 2a1 (first coil portion) and a coil portion 3a1 (second coil portion) in a housing 4. The coil portion 2a1 has a lead wire 2b1 (first lead wire) connected to one end and a lead wire 2d1 (second lead wire) connected to the other end. The coil portion 2a1 and the lead wires 2b1 and 2d1 are collectively referred to as a coil L1a (first coil). The coil portion 3a1 has a lead wire 3b1 (third lead wire) connected to one end and a lead wire 3d1 (fourth lead wire) connected to the other end. The coil portion 3a1 and the lead wires 3b1 and 3d1 are collectively referred to as a coil L2a (second coil). Note that the coil portion 2a1 may also be referred to as coil L1a, and the coil portion 3a1 may also be referred to as coil L2a.

[0025] The coil portion 2a1 has a rectangular shape when viewed from the direction of the main surface 40A and has an opening, and is disposed inside the housing 4 substantially parallel to the main surface 40A. Therefore, the lead wires 2b1 and 2d1 are close to each other and are drawn out from the side surface 41 close to the side surface 44. The lead wire 2b1 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 2c1. The lead wire 2d1 also extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 2e1. When the coil component 1a is mounted on the substrate 10, the end portion 2c1 is electrically connected to the electrode 11 on the substrate 10, and the end portion 2e1 is electrically connected to the electrode 12 on the substrate 10.

[0026] The coil portion 3a1 has a rectangular shape when viewed from the direction of the main surface 40A and has an opening. The coil portion 3a1 is disposed above the coil portion 2a1 inside the housing 4, approximately parallel to the main surface 40A. Therefore, the lead wires 3b1 and 3d1 are brought close to each other and drawn out from the side surface 44 close to the side surface 41. The lead wire 3b1 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 3c1. The lead wire 3d1 also extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 3e1. When the coil component 1a is mounted on the substrate 10, the end portion 3c1 is electrically connected to the electrode 12 on the substrate 10, and the end portion 3e1 is electrically connected to the electrode 13 (third electrode) on the substrate 10.

[0027] Note that end 2e1 and end 3c1 are electrically connected by electrode 12 on substrate 10. By connecting end 2e1 and end 3c1 by electrode 12, coil L1a and coil L2a are connected in series, and a two-turn coil is configured so that the opening of coil L1a and the opening of coil L2a overlap when viewed from the direction of main surface 40A. By bringing the lead wires closer to each other as in coil portion 2a1 and coil portion 3a1 in this way, the positions through which the magnetic lines of force pass are limited compared to coil portions 2a and 3a, the magnetic field is concentrated, and the inductance value can be improved.

[0028] <Embodiment 2> In the first embodiment, it has been described that coil L1 and coil L2 of coil component 1 mounted on substrate 10 are connected in series to form a two-turn coil. In the second embodiment, a coil component that forms a three-turn coil by being mounted on a substrate will be described. FIG. 6 is a perspective view of circuit device 100b according to the second embodiment. FIG. 7 is an example of a circuit diagram of circuit device 100b according to the second embodiment. Note that in circuit device 100b and coil component 1b shown in the second embodiment, the same reference numerals are used for the same components as circuit device 100 and coil component 1 according to the first embodiment, and detailed description thereof will not be repeated.

[0029] The circuit device 100b includes a coil component 1b and a substrate 10 on which the coil component 1b is mounted. The coil component 1b includes three coils, and by mounting the coil component 1b on the substrate 10, a three-turn coil can be formed.

[0030] Coil component 1b includes coil portion 2a (first coil portion), coil portion 3a (second coil portion), and coil portion 5a (third coil portion) in housing 4. Coil portion 2a has lead wire 2b (first lead wire) connected to one end and lead wire 2d (second lead wire) connected to the other end. Coil portion 2a and lead wires 2b and 2d are collectively referred to as coil L1 (first coil). Coil portion 3a has lead wire 3b (third lead wire) connected to one end and lead wire 3d (fourth lead wire) connected to the other end. Coil portion 3a and lead wires 3b and 3d are collectively referred to as coil L2 (second coil). Coil portion 5a has lead wire 5b (fifth lead wire) connected to one end and lead wire 5d (sixth lead wire) connected to the other end. The coil portion 5a and the lead wires 5b and 5d are collectively referred to as coil L3 (third coil). Note that the coil portion 2a may be referred to as coil L1, the coil portion 3a as coil L2, and the coil portion 5a as coil L3.

[0031] The coil portion 2a has a U-shape when viewed from the direction of the main surface 40A, has an opening, and is disposed inside the housing 4 substantially parallel to the main surface 40A. The coil portion 2a is a single-turn coil. The lead wires 2b and 2d are drawn out from the side surface 41 of the housing 4, bent along the side surface 41, and extend toward the main surface 40B. The lead wire 2b shown in FIG. 6 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes the end 2c. The lead wire 2d extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes the end 2e. When the coil component 1b is mounted on the substrate 10, the end 2c is electrically connected to the electrode 11 on the substrate 10, and the end 2e is electrically connected to the electrode 12 on the substrate 10.

[0032] The coil portion 3a has a U-shaped opening when viewed from the direction of the main surface 40A, and is disposed above the coil portion 2a inside the housing 4, approximately parallel to the main surface 40A. The coil portion 3a is a single-turn coil. The lead wires 3b and 3d are drawn out from a side surface 44 adjacent to the side surface 41 of the housing 4, bent along the side surface 44, and extended toward the main surface 40B. The lead wire 3b shown in FIG. 6 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 3c. The lead wire 3d extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes an end portion 3e. When the coil component 1b is mounted on the substrate 10, the end portion 3c is electrically connected to the electrode 12 on the substrate 10, and the end portion 3e is electrically connected to the electrode 13a on the substrate 10.

[0033] The coil portion 5a has a U-shape when viewed from the direction of the main surface 40A, has an opening, and is disposed above the coil portion 3a inside the housing 4, approximately parallel to the main surface 40A. The coil portion 5a is a single-turn coil. The lead wires 5b and 5d are drawn out from the side surface 42 adjacent to the side surface 44 of the housing 4, bent along the side surface 42, and extend toward the main surface 40B. The lead wire 5b shown in FIG. 6 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes the end 5c. The lead wire 5d extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes the end 5e. When the coil component 1b is mounted on the substrate 10, the end 5c is electrically connected to the electrode 13a on the substrate 10, and the end 5e is electrically connected to the electrode 14 on the substrate 10.

[0034] Note that end 2e and end 3c are electrically connected by electrode 12 on substrate 10, and end 3e and end 5c are electrically connected by electrode 13a on substrate 10. Coil L1 and coil L2 are connected in series by connecting end 2e and end 3c by electrode 12, and coil L2 and coil L3 are connected in series by connecting end 3e and end 5c by electrode 13a. Coil component 1b forms a three-turn coil such that the opening of coil L1, the opening of coil L2, and the opening of coil L3 overlap when viewed from the direction of main surface 40A.

[0035] Lead wires 2d and 3b electrically connected to the same electrode 12 are drawn out so as to be close to the corner between side surface 41 and side surface 44, and lead wires 3d and 5b electrically connected to the same electrode 13a are drawn out so as to be close to the corner between side surface 44 and side surface 42. This shortens the connecting distance of lead wires 2d and 3b and the connecting distance of lead wires 3d and 5b, thereby reducing the influence of fluctuations in inductance value due to substrate 10 and heat generation at electrodes 12 and 13a. Here, it is sufficient that the drawing position of at least lead wire 2d of lead wires 2b and 2d is closer to side surface 44 than to side surface 43 adjacent to side surface 41, the drawing position of at least lead wire 3b of lead wires 3b and 3d is closer to side surface 41 than to side surface 42 adjacent to side surface 44, and the drawing position of at least lead wire 5b of lead wires 5b and 5d is closer to side surface 44 than to side surface 43 adjacent to side surface 42.

[0036] When electrode 11 of coil L1 is connected to a power source, current flows from lead wire 2b to coil portion 2a, and the current flows clockwise through coil portion 2a when viewed from the main surface 40A. The current that flows through coil portion 2a flows in the order of lead wire 2d, electrode 12, and lead wire 3b. For coil L2, current flows from lead wire 3b to coil portion 3a, and the current flows clockwise through coil portion 3a when viewed from the main surface 40A. The current that flows through coil portion 3a flows in the order of lead wire 3d, electrode 13a, and lead wire 5b. For coil L3, current flows from lead wire 5b to coil portion 5a, and the current flows clockwise through coil portion 5a when viewed from the main surface 40A. Therefore, magnetic fields are generated in coils L1, L2, and L3 in the direction from main surface 40A to main surface 40B (the -Z direction). When viewed from the direction of the main surface 40A, the coil portion 2a, the coil portion 3a, and the coil portion 5a are arranged to overlap each other, so that the coil L1, the coil L2, and the coil L3 are magnetically coupled.

[0037] Furthermore, when capacitors C1 to C4 are connected to electrodes 11, 12, 13a, and 14, respectively, in circuit device 100b, a high-order filter circuit can be easily configured as shown in Fig. 7. Compared to configuring a high-order filter circuit by mounting multiple coils on substrate 10, circuit device 100b shown in Fig. 7 can save space, and reducing the number of components also increases the reliability of circuit device 100b. Furthermore, while circuit device 100b shown in Fig. 7 is an example of a circuit that combines coil component 1b and capacitors C1 to C4, it may also be a single coil with electrode 11 at one end and electrode 14 at the other end without using a capacitor.

[0038] Although not shown, a fourth coil may be added to coil component 1b. The fourth coil has a U-shape when viewed from the direction of main surface 40A, an opening, and is disposed above coil portion 5a inside housing 4, approximately parallel to main surface 40A. The fourth coil is a single-turn coil, with a lead wire drawn from side surface 43 adjacent to side surface 42 of housing 4, bent along side surface 43, and extending toward main surface 40B. One lead wire of the fourth coil is connected to electrode 14 and electrically connected to lead wire 5d, thereby forming a four-turn coil. Since coil component 1b has a rectangular parallelepiped housing 4, there are only four sides from which the lead wires can be drawn, making it possible to form a four-turn coil. However, if the housing were polygonal prism-shaped, lead wires could be drawn from n-face side surfaces, making it possible to form an n-turn coil.

[0039] (Modification) In coil component 1b, as shown in FIG. 6, lead wires 3b and 3d are bent along side surface 44 and extend straight from main surface 40A to main surface 40B. However, in coil component 1b, lead wires 3b and 3d do not have to be bent along side surface 44 and extend straight from main surface 40A to main surface 40B. FIG. 8 is a perspective view of circuit device 100c according to a modification of embodiment 2. FIG. 9 is a plan view and a side view of coil component 1c according to a modification of embodiment 2. Note that in circuit device 100c and coil component 1c shown in the modification of embodiment 2, the same reference numerals are used for the same components as circuit device 100b and coil component 1b according to embodiment 2, and detailed description thereof will not be repeated.

[0040] Coil component 1c includes coil portion 2a (first coil portion), coil portion 3a2 (second coil portion), and coil portion 5a (third coil portion) in housing 4. Coil portion 2a has one end connected to lead wire 2b (first lead wire) and the other end connected to lead wire 2d (second lead wire). Coil portion 2a and lead wires 2b and 2d are collectively referred to as coil L1 (first coil). Coil portion 3a2 has one end connected to lead wire 3b2 (third lead wire) and the other end connected to lead wire 3d2 (fourth lead wire). Coil portion 3a2 and lead wires 3b2 and 3d2 are collectively referred to as coil L2b (second coil). Coil portion 5a has one end connected to lead wire 5b (fifth lead wire) and the other end connected to lead wire 5d (sixth lead wire). The coil portion 5a and the lead wires 5b and 5d are collectively referred to as coil L3 (third coil). Note that the coil portion 2a may be referred to as coil L1, the coil portion 3a2 as coil L2b, and the coil portion 5a as coil L3.

[0041] The coil portion 3a2 has a rectangular shape when viewed from the direction of the main surface 40A and has an opening. The coil portion 3a2 is disposed above the coil portion 2a inside the housing 4, approximately parallel to the main surface 40A. Therefore, the lead wires 3b2 and 3d2 are drawn out from the center of the side surface 44, bent along the side surface 44, and extend toward the main surface 40B, spreading outward from the center. The lead wire 3b2 shown in FIG. 8 has a crank shape, spreading outward from the center to the main surface 40B, and its portion in contact with the main surface 40B constitutes the end portion 3c2. The lead wire 3d2 also has a crank shape, spreading outward from the center to the main surface 40B, and its portion in contact with the main surface 40B constitutes the end portion 3e2. When the coil component 1c is mounted on the substrate 10, the end portion 3c2 is electrically connected to the electrode 12 on the substrate 10, and the end portion 3e2 is electrically connected to the electrode 13a on the substrate 10.

[0042] As shown in FIG. 9( a), the housing 4 of the coil device 1c has a rectangular shape when viewed from the direction of the main surface 40A, with the shorter side surfaces of the housing 4 being side surfaces 41 and 42 and the longer side surfaces of the housing 4 being side surfaces 43 and 44. By drawing out the lead wires 3b2 and 3d2 from side surface 44, which is the longer side surface of the housing 4, at positions close to each other, the opening of the coil portion 3a2 is made as rectangular as possible, thereby confining the magnetic field lines and strengthening the magnetic coupling between the coil L1, the coil L2b, and the coil L3. As shown in FIG. 9( b), the distance D2 between the lead wires 3b2 and 3d2 at a position on the side surface 44 near the main surface 40B is wider than the distance D1 between the lead wires 3b2 and 3d2 at positions drawn out from side surface 44.

[0043] It should be noted that not only coil portion 3a2 but also coil portions 2a and 5a may have a rectangular shape when viewed from the direction of main surface 40A. The distance between lead wires 2b and 2d at a position on side surface 41 closer to main surface 40B is set wider than the distance between lead wires 2b and 2d at a position on side surface 41 closer to main surface 40B. Furthermore, the distance between lead wires 5b and 5d at a position on side surface 42 closer to main surface 40B is set wider than the distance between lead wires 5b and 5d at a position on side surface 42 closer to main surface 40B. By making the coil portions as closed as possible in this way, the magnetic coupling between the coils can be further strengthened.

[0044] <Third Embodiment> In the second embodiment, it was described that coil component 1b is a three-turn coil in which coils L1 to L3 are connected in series. In the third embodiment, a coil component in which the coils are connected in series and a tap is provided midway will be described. FIG. 10 is a perspective view of circuit device 100d according to the third embodiment. FIG. 11 is an exploded plan view of coil component 1d according to the third embodiment. FIG. 12 is a circuit diagram of circuit device 100d according to the third embodiment. Note that in circuit device 100d and coil component 1d shown in the third embodiment, the same reference numerals are used for the same components as circuit device 100b and coil component 1b according to the second embodiment, and detailed description thereof will not be repeated.

[0045] The circuit device 100d includes a coil component 1d and a substrate 10 on which the coil component 1d is mounted. The coil component 1d includes three coils, and by mounting the coil component 1d on the substrate 10, a three-turn coil can be formed.

[0046] Coil component 1d includes coil portion 2a (first coil portion), coil portion 3a3 (second coil portion), and coil portion 5a (third coil portion) in housing 4. Coil portion 2a has lead wire 2b (first lead wire) connected to one end and lead wire 2d (second lead wire) connected to the other end. Coil portion 2a and lead wires 2b and 2d are collectively referred to as coil L1 (first coil). Coil portion 3a3 has lead wire 3b3 (third lead wire) connected to one end and lead wire 3d3 (fourth lead wire) connected to the other end, with lead wire 3f (seventh lead wire) connected as a tap in the middle. Coil portion 3a and lead wires 3b3, 3d3, and 3f are collectively referred to as coil L2c (second coil). One end of the coil portion 5a is connected to a lead wire 5b (fifth lead wire) and the other end is connected to a lead wire 5d (sixth lead wire). The coil portion 5a and the lead wires 5b and 5d are collectively referred to as a coil L3 (third coil). Note that the coil portion 2a may be referred to as coil L1, the coil portion 3a3 as coil L2c, and the coil portion 5a as coil L3.

[0047] The coil portion 3a3 has a U-shaped opening when viewed from the direction of the main surface 40A, and is disposed below the coil portion 2a inside the housing 4, approximately parallel to the main surface 40A. The coil portion 3a3 is a single-turn coil. The lead wires 3b3 and 3d3 are drawn out from the side surface 44 adjacent to the side surface 41 of the housing 4, bent along the side surface 44, and extended toward the main surface 40B. The lead wire 3b3 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes the end portion 3c3 shown in FIG. 10. The lead wire 3d3 extends to the main surface 40B, and the portion that contacts the main surface 40B constitutes the end portion 3e3. When the coil component 1d is mounted on the substrate 10, the end portion 3c3 is electrically connected to the electrode 12 on the substrate 10, the end portion 5c is electrically connected, and the end portion 3e3 is electrically connected to the electrode 13a ( FIG. 8 ) on the substrate 10. In addition to end 3c3, end 2e of electrode 12 is electrically connected, end 2c of electrode 11 is electrically connected, and end 5e of electrode 14 is electrically connected.

[0048] The lead wire 3f is drawn out from the side surface 43 adjacent to the side surface 41 of the housing 4, bent along the side surface 43, and extends toward the main surface 40B. The portion of the lead wire 3f extending from the main surface 40B is electrically connected to the electrode 15 on the substrate 10. Since the coil portion 3a3 is disposed below the coil portion 2a inside the housing 4, the length of the lead wire 3f can be shortened. By shortening the length of the lead wire 3f, the parasitic inductance occurring in the lead wire 3f can be suppressed. In the coil component 1d, if the parasitic inductance of the lead wire 3f is not a problem, the coil portion 3a3 may be disposed above the coil portion 2a or the coil portion 5a as shown in FIG. 6.

[0049] Because the coil component 1d consists of two magnetically coupled coils and a lead wire 3f extending from the center thereof, the mutual inductance resulting from the magnetic field coupling manifests as negative inductance in the lead wire 3f (center tap). This negative inductance can be used to cancel out the parasitic inductance of the capacitor connected to the electrode 15. Specifically, the circuit device 100d forms a filter circuit including the coil component 1d and the capacitor by connecting a capacitor to the electrode 15. For example, as shown in FIG. 12 , the circuit device 100d is an EMI removal filter and a third-order T-type LC filter circuit. The electrode 11 of the circuit device 100d is connected to a power supply (not shown), and the electrode 14 is connected to a circuit (not shown), such as a DC / DC converter or a power supply module. The circuit device 100d 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 circuit device 100d, and high-frequency noise contained in the direct current is dropped to GND via the capacitor C1.

[0050] However, the capacitor C1, which is a capacitance element, has its own equivalent series inductance ESL (La), which prevents high-frequency noise from passing through, degrading noise removal performance. Therefore, the circuit device 100d 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 of the coil component 1d.

[0051] Although the circuit device 100d will be described using a third-order T-type LC filter circuit as its configuration, coil components of a similar configuration can also be applied to a fifth-order T-type LC filter circuit or a higher-order T-type LC filter circuit. As shown in FIG. 12 , the circuit device 100d includes a capacitor C1, electrodes 11 and 14, a center tap (electrode 15), a coil L1A, and a coil L2A.

[0052] As shown in FIG. 12 , the capacitor C1 has one end connected to the electrode 15 and the other end connected to the GND wiring. The capacitor C1 may be a multilayer ceramic capacitor primarily composed of BaTiO3 (barium titanate), a multilayer ceramic capacitor primarily composed of other materials, or another type of capacitor, such as an aluminum electrolytic capacitor. The capacitor C1 has an inductor La as a parasitic inductance (equivalent series inductance (ESL)), and is equivalent to a circuit configuration in which the inductor La is connected in series with the capacitor C1a. The capacitor C1 may also be equivalent to a circuit configuration in which a parasitic resistance (equivalent series resistance (ESR)) is connected in series with the inductor La and the capacitor C1a.

[0053] In addition to the capacitor C1, coils L1A and L2A are connected to electrode 15. Coils L1A and L2A are magnetically coupled and have mutual inductance. Coil L1A is the portion of coils L1 and L2 shown in FIG. 11 from end 3c3 to lead-out wire 3f, and coil L2A is the portion of coils L3 and L2 from end 3e3 to lead-out wire 3f.

[0054] A negative inductance component of the same magnitude as the mutual inductance is generated between the electrode 15 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 circuit device 100d, which is composed of the capacitor C1, the coil L1A, and the coil L2A, cancels out the parasitic inductance of the capacitor C1 with the negative inductance component due to the mutual inductance between the coils L1A and L2A. This prevents a decrease 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 circuit device 100d.

[0055] <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, i.e., a first side surface, a second side surface, a third side surface, and a fourth side surface, connecting the first and second main surfaces; a first coil disposed inside the housing and having a first coil portion disposed substantially parallel to the first main surface; and a second coil disposed inside the housing such that an opening of the first coil overlaps with an opening of the first coil when viewed from the direction of the first main surface, wherein the first coil has first and second lead wires connected to the first coil portion, drawn from the first side surface side of the housing and bent along the first side surface side; and the second coil has third and fourth lead wires connected to the second coil portion, drawn from a second side surface adjacent to the first side surface and bent along the second side surface side.

[0056] (2) In the coil component described in (1), the first coil portion and the second coil portion have a U-shape when viewed from the direction of the first main surface.

[0057] (3) In the coil component described in (1), the first coil portion and the second coil portion have a rectangular shape when viewed from the direction of the first main surface, the second distance between the first lead-out line and the second lead-out line at a position on the first side closer to the second main surface is wider than the first distance between the first lead-out line and the second lead-out line at a position drawn out from the first side surface, and the fourth distance between the third lead-out line and the fourth lead-out line at a position on the second side closer to the second main surface is wider than the third distance between the third lead-out line and the fourth lead-out line at a position drawn out from the second side surface.

[0058] (4) In the coil component described in any one of (1) to (3), the lead-out position of at least the second lead-out line among the first and second lead-out lines is closer to the second side surface than the third side surface adjacent to the first side surface, and the lead-out position of at least the third lead-out line among the third and fourth lead-out lines is closer to the first side surface than the fourth side surface adjacent to the second side surface.

[0059] (5) The coil component described in any one of (1) to (4) further includes a third coil having a third coil portion disposed inside the housing so that the openings of the first coil and the second coil overlap with each other when viewed from the direction of the first main surface, and the third coil has a fifth lead wire and a sixth lead wire connected to the third coil portion, drawn out from a fourth side surface of the housing, and bent along the fourth side surface.

[0060] (6) In the coil component according to (5), the third coil portion has a U-shape when viewed from the direction of the first main surface.

[0061] (7) In the coil component described in (5), the third coil portion has a rectangular shape when viewed from the direction of the first main surface, and the sixth distance between the fifth and sixth lead wires at the position of the fourth side face closer to the second main surface is wider than the fifth distance between the fifth and sixth lead wires at the position where they are drawn out from the fourth side face.

[0062] (8) In the coil component described in any one of (5) to (7), the lead-out position of at least the fifth lead-out wire among the fifth and sixth lead-out wires is closer to the second side surface than the third side surface adjacent to the fourth side surface, and the lead-out position of at least the fourth lead-out wire among the third and fourth lead-out wires is closer to the fourth side surface than the first side surface adjacent to the second side surface.

[0063] (9) In the coil component described in any one of (5) to (8), the second coil further has a seventh lead wire connected to the second coil portion, drawn out from the third side surface of the housing, and bent along the third side surface.

[0064] (10) In the coil component described in any one of (1) to (9), the housing has a first main surface and a second main surface each having a rectangular shape, the first side surface and the fourth side surface are short side surfaces, and the second side surface and the third side surface are long side surfaces.

[0065] (11) A filter circuit according to the present disclosure is a circuit device including: a coil component according to any one of (1) to (10); and a circuit board on which the coil component is mounted, wherein the circuit board includes: a first electrode electrically connected to the first lead wire; a second electrode electrically connected to the second lead wire and the third lead wire; and a third electrode electrically connected to the fourth lead wire.

[0066] (12) A filter circuit according to the present disclosure is a circuit device including the coil component according to any one of (5) to (9) and a circuit board on which the coil component is mounted, wherein the circuit board includes: a first electrode electrically connected to the first lead wire; a second electrode electrically connected to the second lead wire and the third lead wire; a third electrode electrically connected to the fourth lead wire and the fifth lead wire; and a fourth electrode electrically connected to the sixth lead wire.

[0067] (13) A filter circuit according to the present disclosure is a circuit device including the coil component according to (9) and a circuit board on which the coil component is mounted, wherein the circuit board includes: a first electrode electrically connected to the first lead wire; a second electrode electrically connected to the second lead wire and the third lead wire; a third electrode electrically connected to the fourth lead wire and the fifth lead wire; a fourth electrode electrically connected to the sixth lead wire; and a fifth electrode electrically connecting the seventh lead wire and a capacitor.

[0068] 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.

[0069] 1, 1a to 1d coil components, 2a, 3a, 5a coil portion, 2b, 2d, 3b, 3d, 5b, 5d lead wires, 2c, 2e, 3c, 3e, 5c, 5e end portions, 4 housing, 10 substrate, 11 to 15 electrodes, 100, 100a to 100d circuit device, C1 capacitor.

Claims

1. A coil component comprising: a housing having a pair of first and second main surfaces opposing each other, and four side surfaces, i.e. a first side surface, a second side surface, a third side surface, and a fourth side surface connecting the first main surface and the second main surface; a first coil disposed inside the housing and having a first coil portion disposed substantially parallel to the first main surface; and a second coil disposed inside the housing such that an opening of the first coil overlaps with an opening of the first coil when viewed from the direction of the first main surface, wherein the first coil has first and second lead wires connected to the first coil portion, and are drawn out from the first side surface side of the housing and bent along the first side surface side, and the second coil has third and fourth lead wires connected to the second coil portion, and are drawn out from the second side surface adjacent to the first side surface and bent along the second side surface side.

2. A coil component as described in claim 1, wherein the first coil portion and the second coil portion have a U-shape when viewed from the direction of the first main surface.

3. The coil component described in claim 1, wherein the first coil portion and the second coil portion have a rectangular shape when viewed from the direction of the first main surface, a second distance between the first lead-out wire and the second lead-out wire at a position on the first side surface closer to the second main surface side is wider than a first distance between the first lead-out wire and the second lead-out wire at a position drawn out from the first side surface side, and a fourth distance between the third lead-out wire and the fourth lead-out wire at a position on the second side surface closer to the second main surface side is wider than a third distance between the third lead-out wire and the fourth lead-out wire at a position drawn out from the second side surface side.

4. A coil component described in any one of claims 1 to 3, wherein the pull-out position of at least the second pull-out wire of the first and second pull-out wires is closer to the second side surface than the third side surface adjacent to the first side surface, and the pull-out position of at least the third pull-out wire of the third and fourth pull-out wires is closer to the first side surface than the fourth side surface adjacent to the second side surface.

5. A coil component as claimed in any one of claims 1 to 4, further comprising a third coil having a third coil portion arranged inside the housing such that its opening overlaps with the openings of the first coil and the second coil when viewed from the direction of the first main surface, the third coil having a fifth lead wire and a sixth lead wire connected to the third coil portion, drawn out from the fourth side surface of the housing and bent along the fourth side surface.

6. A coil component as described in claim 5, wherein the third coil portion has a U-shape when viewed from the direction of the first main surface.

7. A coil component as described in claim 5, wherein the third coil portion has a rectangular shape when viewed from the direction of the first main surface, and a sixth distance between the fifth and sixth lead-out wires at a position on the fourth side surface closer to the second main surface is wider than a fifth distance between the fifth and sixth lead-out wires at a position drawn out from the fourth side surface.

8. A coil component described in any one of claims 5 to 7, wherein the pull-out position of at least the fifth pull-out wire of the fifth and sixth pull-out wires is closer to the second side surface side than the third side surface adjacent to the fourth side surface, and the pull-out position of at least the fourth pull-out wire of the third and fourth pull-out wires is closer to the fourth side surface side than the first side surface adjacent to the second side surface.

9. A coil component described in any one of claims 5 to 8, wherein the second coil further has a seventh lead wire connected to the second coil portion, drawn out from the third side surface of the housing and bent along the third side surface.

10. A coil component according to any one of claims 1 to 9, wherein the housing has a rectangular first main surface and a rectangular second main surface, the first side surface and the fourth side surface are short side surfaces, and the second side surface and the third side surface are long side surfaces.

11. A circuit device comprising: a coil component according to any one of claims 1 to 10; and a circuit board on which the coil component is mounted, wherein the circuit board includes: a first electrode electrically connected to the first lead-out wire; a second electrode electrically connected to the second lead-out wire and the third lead-out wire; and a third electrode electrically connected to the fourth lead-out wire.

12. A circuit device comprising: a coil component according to any one of claims 5 to 9; and a circuit board on which the coil component is mounted, wherein the circuit board includes: a first electrode electrically connected to the first lead-out wire; a second electrode electrically connected to the second lead-out wire and the third lead-out wire; a third electrode electrically connected to the fourth lead-out wire and the fifth lead-out wire; and a fourth electrode electrically connected to the sixth lead-out wire.

13. A circuit device comprising: a coil component as described in claim 9; and a circuit board on which the coil component is mounted, wherein the circuit board includes: a first electrode electrically connected to the first lead-out wire; a second electrode electrically connected to the second lead-out wire and the third lead-out wire; a third electrode electrically connected to the fourth lead-out wire and the fifth lead-out wire; a fourth electrode electrically connected to the sixth lead-out wire; and a fifth electrode electrically connecting the seventh lead-out wire and a capacitor.

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