Coil component and filter circuit

Abstract

A coil component (1) according to the present disclosure comprises: a housing (4) including a first main surface and a second main surface that face each other and that form a pair, and four side surfaces that link the first main surface and the second main surface; a coil (L1) that is disposed inside of the housing (4); and a coil (L2) that is disposed inside of the housing (4). The coil component (1) includes a lead-out line (2b) and a lead-out line (2d) which are respectively connected to the end sections of the coil (L1), and a lead-out line (3b) and a lead-out line (3d) which are respectively connected to the end sections of the coil (L2). The lead-out line (2d) and the lead-out line (3d) are electrically connected. The area of at least one among the lead-out line (2d) and the lead-out line (3d) is larger than the area of the lead-out line (2b) and the lead-out line (3b).

Description

Coil components and filter circuits

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

[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 technique is known for broadening the bandwidth of the noise suppression effect of a filter circuit by canceling out the equivalent series inductance ESL of a capacitor with the negative inductance generated by magnetically coupling two coils (see, for example, Japanese Patent Laid-Open No. 2001-160728 (Patent Document 1)). Conventionally, there have been coil components in which the coil is formed by bending a metal plate. Japanese Patent Laid-Open No. 2004-296630 (Patent Document 2) discloses, as an example of a coil component, a coil component having four terminals.

[0004] JP 2001-160728 A JP 2004-296630 A

[0005] When the coil component of Patent Document 2 is used in a filter circuit, heat generated from the terminals connected to the power line is dissipated to the circuit board through a power path designed for heat dissipation. However, because the wiring extending from the terminals connecting the capacitors does not have heat dissipation properties, heat generated from the coil component is not dissipated as adequately from the terminals connecting the capacitors as compared to terminals directly connected to the power path. As a result, the terminals connecting the capacitors are prone to becoming very hot. When such hot terminals are connected to a circuit board, the thin copper foil that makes up the wiring raises concerns about further temperature increases. The temperature increase leads to an increase in the DC resistance component of the coil component, leading to a decrease in the performance of the filter circuit.

[0006] Therefore, an object of the present disclosure is to provide a coil component with high heat dissipation performance and a filter circuit in which the coil component is mounted.

[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 within the housing and substantially parallel to the first main surface, and a second coil disposed within 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 coil component includes a first lead wire and a second lead wire connected to ends of the first coil, respectively, and a third lead wire and a fourth lead wire connected to ends of the second coil, respectively. The second lead wire and the fourth lead wire are electrically connected. At least one of the second lead wire and the fourth lead wire has an area larger than the areas of the first lead wire and the third lead wire.

[0008] 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 within the housing and substantially parallel to the first main surface, and a second coil disposed within 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 coil component includes a first lead wire and a second lead wire connected to ends of the first coil, respectively, and a third lead wire and a fourth lead wire connected to ends of the second coil, respectively. The second lead wire and the fourth lead wire are electrically connected. The distance between the first lead wire and the third lead wire is closer than the distance between the second lead wire and the fourth lead wire.

[0009] A filter circuit according to an embodiment of the present disclosure includes the above-described coil component and a capacitor connected to the coil component.

[0010] According to one embodiment of the present disclosure, the second drawer wire and the fourth drawer wire are electrically connected, and the area of ​​at least one of the second drawer wire or the fourth drawer wire is larger than the area of ​​the first drawer wire and the third drawer wire, thereby improving heat dissipation performance.

[0011] 1 is a perspective view of a coil component according to embodiment 1. FIG. 2 is an upside-down view of the coil component according to embodiment 1. FIG. 3 is a circuit diagram of a filter circuit including the coil component according to embodiment 1. FIG. 4 is a perspective view of a coil component according to embodiment 2. FIG. 5 is an exploded view of a coil according to embodiment 2. FIG. 6 is a perspective view of a coil component according to embodiment 3. FIG. 7 is a perspective view of a coil component according to embodiment 4. FIG. 8 is an exploded view of a coil according to embodiment 4. FIG. 9 is a perspective view of a coil component according to embodiment 5. FIG. 10 is an exploded view of a coil according to embodiment 5. FIG. 11 is a perspective view of a coil component according to embodiment 6.

[0012] <First Embodiment> A coil component according to the first embodiment will be described below. Fig. 1A is a perspective view of a coil component 1 according to the first embodiment. Fig. 1B is an upside-down view of the coil component according to the first embodiment. Fig. 2 is a circuit diagram of a filter circuit 100 including the coil component 1 according to the first embodiment. When the X-axis, Y-axis, and Z-axis are defined as shown in Fig. 1A, the X-axis direction is the left-right direction of the coil component 1, the Y-axis direction is the front-rear direction of the coil component 1, and the Z-axis direction is the up-down direction of the coil component 1.

[0013] The coil component 1 is, for example, a transformer coil mounted in a filter circuit 100 used to suppress noise in a power line. As will be described later, the coil component 1 magnetically couples two coils to cancel the parasitic inductance of a capacitor mounted in the filter circuit. Furthermore, the coil component 1 employs a structure in which the terminals of the two coils are used to form a third coil.

[0014] The coil component 1 includes a coil portion 2a (first coil) and a coil portion 3a (second coil) housed within a housing 4. Hereinafter, the coil portion 2a will also be referred to as coil L1, and the coil portion 3a will also be referred to as coil L2. The coils L1 and L2 are formed from metal plates, such as copper or an alloy of copper and other metals. 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 the insulating material is provided at least on the surfaces where the coils L1 and L2 face each other. Furthermore, although a single-turn coil is illustrated in this disclosure, a coil formed from multiple layers may also be used.

[0015] The coil portion 2a has one end connected to a lead wire 2b (first lead wire) and the other end connected to a lead wire 2d (second lead wire). The lead wire 2b includes an electrode 2c that functions as an electrode, and the lead wire 2d includes an electrode 2e that functions as an electrode. The coil portion 2a and the lead wires 2b and 2d form a single first conductor 2. The lead wires 2b and 2d are also terminals extending from one end of the coil portion 2a, and are therefore also referred to as terminals 2b and 2d.

[0016] The coil portion 3a has one end connected to a lead wire 3b (third lead wire) and the other end connected to a lead wire 3d (fourth lead wire). The lead wire 3b includes an electrode 3c that functions as an electrode, and the lead wire 3d includes an electrode 3e that functions as an electrode. The coil portion 3a and the lead wires 3b and 3d form a single second conductor 3. The lead wires 3b and 3d are also referred to as terminals 3b and 3d because they also serve as terminals extending from one end of the coil portion 3a.

[0017] The first conductor 2 including the coil L1 and the second conductor 3 including the coil L2 are formed by punching out a pattern from a single metal plate and bending the punched pattern. The bent portions between the coil L1 (coil portion 2a) and the lead wires 2b and 2d, and the bent portions between the electrodes 2c and 2e and the other regions of the lead wires 2b and 2d, are formed by bending, resulting in a substantially right-angle structure with a radius of curvature. Similarly, the bent portions between the coil L2 (coil portion 3a) and the lead wires 3b and 3d, and the bent portions between the electrodes 3c and 3e and the other regions of the lead wires 3b and 3d, are also formed by bending, resulting in a substantially right-angle structure with a radius of curvature. In this way, the bent portions form arcs with a constant radius. The first conductor 2 and the second conductor 3 may also be formed from one or more wires, and the wires may be similarly bent to form arcs with a constant radius at the bent portions.

[0018] The coils L1 and L2 are arranged so that their openings overlap. While FIG. 1A shows an example in which the openings nearly overlap, the openings may be offset as long as magnetic field coupling is achieved, as long as at least 50% of each opening overlaps. A magnetic field is generated in the coil L1 when a current flows from the electrode 2c of the first conductor 2 in the direction indicated by the arrow (clockwise), and a magnetic field in the same direction as the magnetic field of the coil L1 is generated in the coil L2 when a current flows from the electrode 2e to the electrode 3e of the second conductor 3. The coils L1 and L2 are electrically connected by connecting the small gap between the electrodes 2e and 3e with a connecting member (not shown), but the electrodes 2e and 3e may also be connected by a mounting board without using a connecting member. In addition to the coil portion 2a (coil L1) and the coil portion 3a (coil L2), the coil component 1 becomes a third coil L3 when a current flows in the direction indicated by the arrow (counterclockwise) through an opening formed by the lead wire 2d, the electrode 2e, the connecting member 5, the electrode 3e, and the lead wire 3d, generating a magnetic field.

[0019] The housing 4 is made of molded resin for fixing the coils L1 and L2. Specifically, the molded resin is made of one of epoxy resin with added silica filler, silicone resin, liquid crystal polymer, and various resins mixed with metal magnetic material. While Fig. 1A shows 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 approximately parallel. For example, the housing 4 may be a trapezoid in which the area of ​​the second main surface is larger than that of the first main surface.

[0020] FIG. 2 is a circuit diagram of a filter circuit 100 including the coil component 1 according to the first embodiment. The filter circuit 100 is, for example, an EMI filter and a third-order T-type LC filter circuit. The electrode 2c of this filter circuit 100 is connected to a power supply (not shown), and the electrode 3c 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. The capacitor C1, which is a capacitance element, has an equivalent series inductance (ESL) (La), which prevents high-frequency noise from passing through, thereby degrading noise removal performance. The filter circuit 100 uses the negative inductance generated in series with the capacitor C1 due to the mutual inductance caused by the magnetic coupling between the two coils to cancel the ESL (La) of the capacitor, thereby maintaining high noise removal performance.

[0021] In the following embodiment, a third-order T-type LC filter circuit will be used as the configuration of the filter circuit 100, but coil components with similar configurations can also be applied to fifth-order T-type LC filter circuits or higher-order T-type LC filter circuits. As shown in Fig. 2, the filter circuit 100 includes a coil component 1 and a capacitor C1. The coil component 1 includes electrodes 2c and 3c, an intermediate terminal T (electrodes 2e and 3e, a connecting member), a coil L1, and a coil L2.

[0022] As shown in FIG. 2, 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 ３ The 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.

[0023] In addition to the capacitor C1, coils L1 and L2 are also connected to the intermediate terminal T. The coils L1 and L2 are magnetically coupled and have mutual inductance. A negative inductance component of the same magnitude as the mutual inductance 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, coil L1, and coil L2, cancels out the parasitic inductance of the capacitor C1 with the negative inductance component due to the mutual inductance between coils L1 and L2, thereby suppressing a decrease in the noise suppression effect in the high frequency band caused by the parasitic inductance of the capacitor C1 and improving the noise suppression effect of the filter circuit 100.

[0024] In the case of a three-terminal coil component that does not have the structure of coil L3 as in the present application and in which the part directly connecting coils L1 and L2 is intermediate terminal T, a wire is drawn from intermediate terminal T and connected to capacitor C1, which generates positive parasitic inductance in the wire. When this coil component is used in a filter circuit, the positive parasitic inductance generated in the wire cancels out part of the negative inductance component due to the mutual inductance between coils L1 and L2, reducing the negative inductance component of coil component 1, which makes it impossible to sufficiently cancel out the parasitic inductance of capacitor C1 and reduces the noise suppression effect in the high-frequency band.

[0025] Therefore, in the coil component 1 according to the first embodiment, instead of simply drawing out a wire from the intermediate terminal T connecting the coils L1 and L2 and connecting it to the capacitor C1, a coil (coil L3) is formed using terminals 2d, 3d, and connecting members as shown in FIG. 1A and connected to the capacitor C1. Specifically, of terminals 2d and 3d, electrodes 2e and 3e on the second main surface are electrically connected to the wiring on the substrate, and are connected to the capacitor C1 that is electrically connected to the same wiring. In the coil component 1, the coil L3 itself, which is connected to the capacitor C1, is also coupled as part of the coils L1 and L2, and therefore contributes to the negative inductance component due to the mutual inductance between the coils L1 and L2, and does not reduce the negative inductance component.

[0026] Furthermore, the intermediate terminal T that connects coils L1 and L2 is a coil (coil L3) that is composed of terminals 2d, 3d, and connecting member 5, so the three coils L1 to L3 have a relationship in which they have a positive coupling coefficient.

[0027] Electrodes 2c and 3c of coil component 1 are connected to a power supply line. Heat generated from the coil near electrodes 2c and 3c connected to the power supply line is dissipated through the power supply line. In contrast, when coil component 1 is used as a filter circuit, heat generated from the coil near electrodes 2e and 3e connected to a capacitor is not properly dissipated like the power supply line because the coil is connected to wiring that does not have sufficient heat dissipation measures, unlike the power supply line which has heat dissipation measures.

[0028] Furthermore, a large current of several amperes flows from electrode 2c to electrode 2e, via the connecting member, and then from electrode 3e to electrode 3c. However, when the connecting member is formed by printing or coating, the resistance of the connecting member becomes higher than the resistance of the metal plates forming coils L1 and L2, resulting in heat generation, particularly in the connecting member. Therefore, in coil component 1, as shown in FIG. 1B , the distance between electrodes 2e and 3e is made shorter than the distance between electrodes 2c and 3c. That is, by shortening the shortest distance between lead wire 2d and lead wire 3d compared to the shortest distance between lead wire 2b and lead wire 3b, a sufficient distance is maintained between electrodes 2c and 3c to prevent a short circuit when mounted on a board, while the heat-generating area between electrodes 2e and 3e is shortened, thereby improving the heat dissipation performance of coil component 1. The connecting member between electrodes 2e and 3e may be located on the mounting board rather than in coil component 1. By arranging electrodes 2e and 3e at a distance shorter than the distance between electrodes 2c and 3c, the distance over which the current flows on the substrate is reduced, and the current flows mainly through the highly conductive metals of the first conductor 2 and the second conductor 3, thereby suppressing the effects of heat generation. Note that, in this specification, the shortest distance between the lead lines is defined as the shortest distance in the direction in which each lead line extends (the Y-axis direction in the figure) on the second main surface. In this specification, the lead lines are spaced apart and opposite each other in the Y-axis direction, but they may also be opposite each other in the X-axis direction. In this case, the shortest distance in the extension direction of the lead lines is also compared.

[0029] <Embodiment 2> In embodiment 2, compared to embodiment 1, the positions at which the lead wires are drawn out are changed in coil L1 and coil L2, and a configuration in which there is no electrode portion on the second main surface will be described. Fig. 3A is a perspective view of coil component 1A according to embodiment 2. Fig. 3B is an exploded view of the coil according to embodiment 2. Note that in coil component 1A shown in embodiment 2, the same components as those in coil component 1 according to embodiment 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0030] The first conductor 2 has lead wires 2b and 2d extending from the coil L1 to the rear surface of the housing 4, with lead wire 2b being disposed on the rear surface of the housing 4 and lead wire 2d extending from the rear surface to the right side of the housing 4. The second conductor 3 has lead wires 3b and 3d extending from the coil L2 to the front surface of the housing 4, with lead wire 3b being disposed on the front surface of the housing 4 and lead wire 3d extending from the front surface to the right side of the housing 4.

[0031] The areas of the lead wires 2d and 3d are larger than the areas of the lead wires 2b and 3b. Specifically, the area of ​​the lead wires extending from the bent portions connected to the coil portion 2a or 3a to the second main surface, as viewed in the thickness direction of the coil, is the area of ​​the lead wires. This allows for a larger area for dissipating heat generated by the lead wires 2d and 3d, thereby improving the heat dissipation performance of the coil component 1A. Furthermore, the cross-sectional areas of the ends of the lead wires 2d and 3d facing the second main surface are larger than the cross-sectional areas of the ends of the lead wires 2d and 3d facing the second main surface. This increases the area of ​​connection of the lead wires 2d and 3d with the mounting board, improving heat dissipation. Note that, as in this embodiment, the length in the extension direction may be changed, or the area may be changed by changing the width of the coil.

[0032] The first conductor 2 is configured such that the lead wires 2b and 2d expand after the coil is closed at the lead wires 2b and 2d. The second conductor 3 is configured such that the lead wires 3b and 3d expand after the coil is closed at the lead wires 3b and 3d. This enables the coil device 1A to reduce the effects of parasitic inductance and parasitic capacitance of the electrodes that occur when the lead wires 2b and 2d, and the lead wires 3b and 3d, are too close to each other.

[0033] In the coil component 1A, the positions of the lead wires 2b, 2d, 3b, and 3d can be arranged as shown in FIG. 3A , which improves the degree of freedom of wiring on the mounting substrate, etc., and also increases the area of ​​the electrodes formed on the side surface of the housing, thereby improving heat dissipation. Note that, as with the coil component 1 of embodiment 1, the electrodes extending from the lead wires 2b, 2d, 3b, and 3d may be arranged on the underside. One of the multiple electrodes may be arranged on the underside, and the other may be arranged on the side. Note that, although the diagrams are drawn at right angles as a schematic diagram, the bent portions are arc-shaped because they are formed by bending.

[0034] <Embodiment 3> In embodiment 3, compared to embodiment 1, the positions at which the lead wires are drawn out are changed in coil L1 and coil L2, and a configuration in which there are no electrode portions on the second main surface will be described. Fig. 4 is a perspective view of coil component 1B according to embodiment 3. Note that in coil component 1B shown in embodiment 3, the same components as those in coil component 1 according to embodiment 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0035] The first conductor 2 has a lead wire 2b from the coil L1 drawn out from the rear surface of the housing 4, with the end of the lead wire 2b being located on the rear surface, a lead wire 2d drawn out from the right side surface of the housing 4, with the end of the lead wire 2d being located on the right side surface of the housing 4. The second conductor 3 has a lead wire 3b from the coil L2 drawn out from the front surface of the housing 4, with the end of the lead wire 3b being located on the front surface of the housing 4, a lead wire 3d drawn out from the right side surface of the housing 4, with the end of the lead wire 3d being located on the right side surface of the housing 4.

[0036] The areas of the lead wires 2d and 3d are larger than the areas of the lead wires 2b and 3b. This allows for a larger area for dissipating heat generated in the lead wires 2d and 3d, thereby improving the heat dissipation performance of the coil component 1B. Furthermore, the cross-sectional areas of the ends of the lead wires 2d and 3d facing the second main surface are larger than the cross-sectional areas of the ends of the lead wires 2d and 3d facing the second main surface. This increases the area of ​​connection between the lead wires 2d and 3d and the mounting board, improving heat dissipation.

[0037] The first conductor 2 is configured such that the lead wires 2b and 2d expand after the coil is closed at the lead wires 2b and 2d. The second conductor 3 is configured such that the lead wires 3b and 3d expand after the coil is closed at the lead wires 3b and 3d. This enables the coil device 1A to reduce the effects of parasitic inductance and parasitic capacitance of the electrodes that occur when the lead wires 2b and 2d, and the lead wires 3b and 3d, are too close to each other.

[0038] In the coil component 1B, the positions of the lead wires 2b, 2d, 3b, and 3d can be arranged as shown in Figure 4, thereby improving the degree of freedom of wiring on the substrate on which it is mounted. Note that, as with the coil component 1 of embodiment 1, the electrodes extending from the lead wires 2b, 2d, 3b, and 3d may be arranged on the underside. One of the multiple electrodes may be arranged on the underside and the other on the side. Note that, although the diagram shows a schematic diagram with a right angle, the bent portion is formed by bending, and therefore has an arc shape.

[0039] <Fourth Embodiment> In the fourth embodiment, compared to the first embodiment, the positions at which the lead wires are drawn out are changed in the coils L1 and L2, and a configuration in which there are no electrode portions on the second main surface will be described. Fig. 5A is a perspective view of a coil component 1C according to the fourth embodiment. Fig. 5B is an exploded view of the coil according to the fourth embodiment. Note that in the coil component 1C shown in the fourth embodiment, the same components as those in the coil component 1 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0040] In the first conductor 2, leads 2b and 2d are drawn from the coil L1 from the left side surface of the housing 4, with lead 2b extending from the left side surface to the rear surface of the housing 4 and lead 2d extending from the left side surface to the front surface of the housing 4. In the second conductor 3, leads 3b and 3d are drawn from the coil L2 from the right side surface of the housing 4, with lead 3b extending from the right side surface to the rear surface of the housing 4 and lead 3d extending from the right side surface to the front surface of the housing 4. In the fourth embodiment, most of the leads 2b, 2d, 3b, and 3d are embedded inside the housing 4, and only portions of the leads near the ends that reach the second main surface are exposed from the housing 4.

[0041] The areas of the lead wires 2d and 3d are larger than the areas of the lead wires 2b and 3b. This allows for a larger area for dissipating heat generated in the lead wires 2d and 3d, thereby improving the heat dissipation performance of the coil component 1C. Furthermore, the cross-sectional areas of the ends of the lead wires 2d and 3d are larger than the cross-sectional areas of the ends of the lead wires 2b and 3b. This increases the area of ​​connection between the lead wires 2d and 3d and the mounting board, improving heat dissipation performance.

[0042] The first conductor 2 is configured such that the lead wires 2b and 2d expand after the coil is closed at the lead wires 2b and 2d. The second conductor 3 is configured such that the lead wires 3b and 3d expand after the coil is closed at the lead wires 3b and 3d. This enables the coil device 1A to reduce the effects of parasitic inductance and parasitic capacitance of the electrodes that occur when the lead wires 2b and 2d, and the lead wires 3b and 3d, are too close to each other.

[0043] In the coil component 1C, the positions of the lead wires 2b, 2d, 3b, and 3d can be arranged as shown in FIG. 5A , thereby improving the degree of freedom of wiring on a substrate or the like to which the component is mounted. Note that, as with the coil component 1 of embodiment 1, the electrodes extending from the lead wires 2b, 2d, 3b, and 3d may be arranged on the underside. One of the multiple electrodes may be arranged on the underside, and the other may be arranged on the side. Note that, although the diagrams are drawn at right angles as a schematic diagram, the bent portions are arc-shaped because they are formed by bending.

[0044] <Embodiment 5> In embodiment 5, compared to embodiment 1, the positions at which the lead wires are drawn out are changed in coil L1 and coil L2, and a configuration in which there are no electrode portions on the second main surface will be described. Fig. 6A is a perspective view of a coil component 1D according to embodiment 5. Fig. 6B is an exploded view of the coil according to embodiment 2. Note that in coil component 1D shown in embodiment 5, the same components as those in coil component 1 according to embodiment 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0045] The first conductor 2 has a lead wire 2b from the coil L1 drawn out from the rear surface of the housing 4 and the lead wire 2b is arranged on the rear surface of the housing 4, a lead wire 2d drawn out from the left side surface of the housing 4 and the lead wire 2d is arranged on the left side surface of the housing 4. The second conductor 3 has a lead wire 3b from the coil L2 drawn out from the right side surface of the housing 4 and the lead wire 3b is arranged on the right side surface of the housing 4, a lead wire 3d drawn out from the front surface of the housing 4 and the lead wire 3d is arranged on the front surface of the housing 4.

[0046] The areas of the lead wires 2d and 3d are larger than the areas of the lead wires 2b and 3b. This allows for a larger area for dissipating heat generated by the lead wires 2d and 3d, thereby improving the heat dissipation performance of the coil component 1D. Furthermore, the cross-sectional areas of the ends of the lead wires 2d and 3d are larger than the cross-sectional areas of the ends of the lead wires 2b and 3b. This increases the area where the lead wires 2d and 3d connect to the mounting board, improving heat dissipation. Furthermore, by forming one terminal on each side, as shown in FIG. 6A, miniaturization is possible and the terminal width can also be made wider.

[0047] The first conductor 2 is configured such that the lead wires 2b and 2d expand after the coil is closed at the lead wires 2b and 2d. The second conductor 3 is configured such that the lead wires 3b and 3d expand after the coil is closed at the lead wires 3b and 3d. This enables the coil device 1A to reduce the effects of parasitic inductance and parasitic capacitance of the electrodes that occur when the lead wires 2b and 2d, and the lead wires 3b and 3d, are too close to each other.

[0048] In the coil component 1D, the positions of the lead wires 2b, 2d, 3b, and 3d can be arranged as shown in FIG. 6A , thereby improving the degree of freedom of wiring on the substrate on which the component is mounted. As with the coil component 1 of embodiment 1, the electrodes extending from the lead wires 2b, 2d, 3b, and 3d may be arranged on the underside. One of the multiple electrodes may be arranged on the underside, and the other may be arranged on the side. Although the diagrams show the components at right angles as a schematic diagram, the bent portions are arc-shaped because they are formed by bending.

[0049] Sixth Embodiment In a sixth embodiment, a configuration in which the lengths of electrodes 2e and 3e are the same as the lengths of electrodes 2c and 3c will be described in comparison with the first embodiment. Fig. 7 is a perspective view of a coil component 1E according to the sixth embodiment. Note that in the coil component 1E shown in the sixth embodiment, the same components as those in the coil component 1 according to the first embodiment are designated by the same reference numerals and will not be described in detail again.

[0050] In coil component 1E, the length of electrode 2e of first conductor 2 is the same as the length of electrode 2c of first conductor 2, and the length of electrode 3e of second conductor 3 is the same as the length of electrode 3c of second conductor 3. A connection member 5 that electrically connects electrode 2e and electrode 3e is disposed between electrode 2e and electrode 3e. The connection member 5 is T-shaped with its tip extending from electrodes 2e and 3e toward the left side surface of housing 4.

[0051] The area of ​​the electrodes 2e and 3e is the same as the area of ​​the electrodes 2c and 3c, but the area that can dissipate the heat generated by the electrodes 2e and 3e is increased by the connecting member 5. This improves the heat dissipation performance of the coil component 1E.

[0052] <Modifications> In the above-described embodiment, the area of ​​at least one of the electrodes 2e, 3e, and the connecting member 5 may be larger than the area of ​​the electrodes 2c and 3c.

[0053] The coils L1 and L2 may not be made of a single metal plate, but may have a multi-layer structure in which a coil component is formed by stacking multiple layers.

[0054] In the above embodiment, the case where the housing 4 has a rectangular parallelepiped shape has been described. However, the housing 4 may have any shape, such as a cylindrical shape.

[0055] <Aspects> (1) A coil component disclosed herein 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 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 coil component includes a first lead wire and a second lead wire connected to ends of the first coil, respectively, and a third lead wire and a fourth lead wire connected to ends of the second coil, respectively. The second lead wire and the fourth lead wire are electrically connected. At least one of the second lead wire and the fourth lead wire has an area larger than the areas of the first lead wire and the third lead wire.

[0056] According to the coil component of the present disclosure, the second draw-out wire and the fourth draw-out wire are electrically connected, and the area of ​​at least one of the second draw-out wire or the fourth draw-out wire is larger than the area of ​​the first draw-out wire and the third draw-out wire, thereby improving heat dissipation performance.

[0057] (2) A coil component according to 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 within the housing and substantially parallel to the first main surface, and a second coil disposed within 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 coil component also includes a first lead wire and a second lead wire connected to ends of the first coil, respectively, and a third lead wire and a fourth lead wire connected to ends of the second coil, respectively. The shortest distance between the first lead wire and the third lead wire is greater than the shortest distance between the second lead wire and the fourth lead wire.

[0058] According to the coil component of the present disclosure, it is possible to ensure a sufficient distance between the first and third draw-out wires to prevent a short circuit when mounted on a board, while shortening the heat-generating area between the second and fourth draw-out wires, thereby improving the heat dissipation performance of the coil component.

[0059] (3) In the coil component according to (2), the shortest distance between the first lead wire and the third lead wire is at a position on the second main surface or on the side surface closest to the second main surface, and the shortest distance between the second lead wire and the fourth lead wire is at a position on the second main surface or on the side surface closest to the second main surface, thereby improving heat dissipation performance at a position close to the second main surface.

[0060] (4) In the coil component according to any one of (1) to (3), the first coil and the second coil are formed from a metal plate or a metal wire, which makes it possible to easily mold the first coil and the second coil from the metal plate or the metal wire.

[0061] (5) In the coil component according to any one of (1) to (4), the first coil and the second coil have rectangular openings, which allows the first coil and the second coil to have large inductance values.

[0062] (6) In the coil component according to any one of (1) to (5), the areas of the second and fourth lead wires are larger than the areas of the first and third lead wires, thereby increasing the area for dissipating heat generated in the second and fourth lead wires, thereby improving the heat dissipation performance of the coil component.

[0063] (7) In the coil component according to any one of (1) to (6), the areas of the first and third lead wires on the second main surface are smaller than the areas of the second and fourth lead wires on the second main surface, thereby increasing the area for dissipating heat generated in the second and fourth lead wires and improving the heat dissipation performance of the coil component.

[0064] (8) In the coil component according to (1), the shortest distance between the first and third lead wires on the second main surface is longer than the shortest distance between the second and fourth lead wires on the second main surface, thereby shortening the heat-generating region between the second and fourth lead wires and improving the heat dissipation performance of the coil component.

[0065] (9) In the coil component according to any one of (1) to (8), the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are arranged on a side surface of the housing, thereby improving the degree of freedom in arranging the lead wires.

[0066] (10) In the coil component according to any one of (1) to (9), the second lead wire and the fourth lead wire are arranged on the same side surface, thereby improving the degree of freedom in arranging the lead wires.

[0067] (11) The coil component according to any one of (1) to (10), further comprising a connecting member disposed on the second main surface and electrically connecting the second lead wire and the fourth lead wire, thereby enabling heat dissipation in the connecting member and improving the heat dissipation performance of the coil component.

[0068] (12) In the coil component according to (11), the area of ​​the connection member is larger than the areas of the first lead wire and the third lead wire. This allows heat to be dissipated in the connection member, thereby improving the heat dissipation performance of the coil component.

[0069] (13) A filter circuit according to the present disclosure includes the coil component according to any one of (1) to (12) and a capacitor electrically connected to the second lead wire and the fourth lead wire. This allows the filter circuit to be equipped with a coil component with high heat dissipation performance.

[0070] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure 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.

[0071] 1, 1A, 1B, 1C, 1D, 1E Coil components, 2a, 3a Coil portions, 2b, 2d, 3b, 3d Lead wires, 2c, 2e, 3c, 3e Electrodes, 4 Housing, 5 Connection member, L1, L2, L3 Coil, S1, S2 Openings

Claims

1. a housing having a pair of first and second main surfaces opposed to each other and four side surfaces connecting the first and second main surfaces; A first coil is disposed inside the housing and is disposed substantially parallel to the first main surface; a second coil disposed inside the housing so that an opening of the first coil overlaps an opening of the second coil when viewed from the first main surface, a first lead wire and a second lead wire respectively connected to ends of the first coil; a third lead wire and a fourth lead wire respectively connected to ends of the second coil, the second lead wire and the fourth lead wire are electrically connected to each other, an area of ​​at least one of the second lead-out line and the fourth lead-out line is larger than an area of ​​the first lead-out line and an area of ​​the third lead-out line; an area of ​​the second lead wire and an area of ​​the fourth lead wire are larger than an area of ​​the first lead wire and an area of ​​the third lead wire.

2. a housing having a pair of first and second main surfaces opposed to each other and four side surfaces connecting the first and second main surfaces; A first coil is disposed inside the housing and is disposed substantially parallel to the first main surface; 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 first main surface, a first lead wire and a second lead wire respectively connected to ends of the first coil; a third lead wire and a fourth lead wire respectively connected to ends of the second coil, a shortest distance between the first lead-out line and the third lead-out line is greater than a shortest distance between the second lead-out line and the fourth lead-out line; an area of ​​the second lead wire and an area of ​​the fourth lead wire are larger than an area of ​​the first lead wire and an area of ​​the third lead wire.

3. 3. The coil component according to claim 2, wherein the shortest distance between the first lead-out wire and the third lead-out wire is at a position within the second main surface or on the side closest to the second main surface, and the shortest distance between the second lead-out wire and the fourth lead-out wire is at a position within the second main surface or on the side closest to the second main surface.

4. The coil component according to any one of claims 1 to 3, wherein the first coil and the second coil are formed from a metal plate or a metal wire.

5. The coil component according to any one of claims 1 to 3, wherein the first coil and the second coil have a rectangular opening.

6. The coil component according to any one of claims 1 to 3, wherein an area of ​​the first lead wire and the third lead wire on the second main surface is smaller than an area of ​​the second lead wire and the fourth lead wire on the second main surface.

7. The coil component according to claim 1 , wherein a shortest distance between the first lead wire and the third lead wire on the second main surface is longer than a shortest distance between the second lead wire and the fourth lead wire on the second main surface.

8. The coil component according to any one of claims 1 to 3, wherein the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are arranged on a side surface of the housing.

9. The coil component according to claim 1 , wherein the second lead wire and the fourth lead wire are arranged on the same side surface.

10. The coil component according to claim 1 , further comprising a connection member disposed on the second main surface and electrically connecting the second lead wire and the fourth lead wire.

11. The coil component according to claim 10 , wherein an area of ​​the connection member is larger than areas of the first lead wire and the third lead wire.

12. The coil component according to any one of claims 1 to 3, a capacitor electrically connected to the second lead line and the fourth lead line.