Coil component and filter circuit

Abstract

A coil component (1) of the present disclosure comprises: a housing (4) having a pair of first main surface and a second main surface facing each other; a coil (L1) disposed in the housing (4); and a coil (L2) disposed in the housing (4). The coils (L1, L2) each comprise a single winding that has no portion overlapping another portion of the coil (L1, L2) when viewed from the first main surface. Bending portions are provided between the coil (L1) and a lead-out line (2b), between the coil (L1) and a lead-out line (2d), between the coil (L2) and a lead-out line (3b), and between the coil (L2) and a lead-out line (3d).

Description

Coil component, filter circuit, and circuit device

[0001] The present disclosure relates to a coil component, a filter circuit incorporating the coil component, and a circuit device.

[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] The coil component of Patent Document 2 has a multi-layer coil formed by folding metal so that coil portions overlap each other to increase the inductance value. When attempting to form a coil with two or more turns by folding a metal sheet, a 180-degree bend is created. Because springback occurs at such bends, it is difficult to form two layers of metal in close proximity and parallel to each other. The springback phenomenon occurs when bending metal, causing compressive stress at the inner edge of the bent portion and tensile stress at the outer edge of the bent portion, resulting in compressed metal molecules trying to spread apart and stretched molecules trying to pull back together.

[0006] The springback phenomenon becomes more pronounced as the bending radius becomes smaller. Therefore, when forming two layers close together like the coil component in Patent Document 2, it is difficult to form the two layers parallel to each other due to the springback phenomenon. Furthermore, when creating a transformer by placing two coils made of such non-parallel metal layers close together, it is difficult to form a stable positional relationship between the two coils, resulting in large variations in the mutual inductance value.

[0007] Therefore, an object of the present disclosure is to provide a coil component that can provide a stable mutual inductance value, a filter circuit that mounts the coil component, and a circuit device.

[0008] A coil component according to an embodiment of the present disclosure includes: a housing having a pair of first and second principal surfaces facing each other; a first coil section including a first coil disposed inside the housing and substantially parallel to the first principal surface, a first lead wire and a second lead wire connected to ends of the first coil, 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 principal surface, and a second coil section including a third lead wire and a fourth lead wire connected to ends of the second coil, wherein the first coil has one turn and does not have a portion overlapping with other portions of the first coil when viewed from the first principal surface, and the second coil has one turn and does not have a portion overlapping with other portions of the second coil when viewed from the first principal surface, and has first bends between the first coil and the first lead wire, between the first coil and the second lead wire, between the second coil and the third lead wire, and between the second coil and the fourth lead wire. The first and second lead lines are arranged such that the distance between them on the first main surface side is shorter than the distance between them on the second main surface side. The third and fourth lead lines are arranged such that the distance between them on the first main surface side is shorter than the distance between them on the second main surface side. The first, second, third, and fourth lead lines are shaped so that their width on the second main surface side is wider than their width on the first main surface side.

[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] A circuit device according to an embodiment of the present disclosure includes a coil component and a circuit board on which the coil component is mounted. The coil component includes: a housing having a pair of opposing first and second main surfaces; a first coil section disposed within the housing and substantially parallel to the first main surface, the first coil section having a first lead wire and a second lead wire connected to each end of the first coil; a second coil disposed within the housing such that an opening of the first coil overlaps an opening of the first coil when viewed from the first main surface; and a second coil section having a third lead wire and a fourth lead wire connected to each end of the second coil. The first coil has one turn and does not have a portion overlapping with other portions of the first coil when viewed from the first main surface, and the second coil has one turn and does not have a portion overlapping with other portions of the second coil when viewed from the first main surface, and has first bends between the first coil and the first lead-out wire, between the first coil and the second lead-out wire, between the second coil and the third lead-out wire, and between the second coil and the fourth lead-out wire. The circuit board includes a first wiring pattern electrically connected to the first lead-out wire, a second wiring pattern electrically connected to the third lead-out wire, and a third wiring pattern electrically connected to the second and fourth lead-out wires and electrically connecting the second and fourth lead-out wires.

[0011] According to one aspect of the present disclosure, the first coil and the second coil can function as a single-turn coil without bending, thereby forming a stable mutual inductance value.

[0012] 1 is a perspective view of a coil component according to a first embodiment; FIG. 2 is a circuit diagram of a filter circuit including the coil component according to the first embodiment; FIG. 3 is a perspective view of a coil component according to a second embodiment; FIG. 4 is an exploded view of a coil according to the second embodiment; FIG. 5 is a perspective view of a coil component according to a third embodiment; FIG. 6 is a perspective view of a coil component according to a fourth embodiment; FIG. 7 is a perspective view of a coil component according to a fifth embodiment; FIG. 8 is a right side view of a coil component according to the fifth embodiment; FIG. 9 is a perspective view of a coil component according to a first modification; FIG. 10 is a plan view of a coil component according to the first modification; FIG. 11 is a right side view of a coil component according to the first modification; FIG. 12 is a perspective view of a coil component according to a second modification; FIG. 13 is a schematic diagram illustrating a configuration of a circuit device according to a third modification; FIG. 14 is a perspective view of a coil component according to a third modification.

[0013] <First Embodiment> A coil component according to the first embodiment will be described below. Fig. 1 is a perspective view of the coil component 1 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. 1, 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.

[0014] 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.

[0015] The coil component 1 includes a coil portion 2a (first coil) and a coil portion 3a (second coil) housed in 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.

[0016] 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. Furthermore, the lead wire 2b is provided with an electrode 2c (first end) that functions as an electrode, and the lead wire 2d is provided with an electrode 2e (second end) that functions as an electrode. The coil portion 2a, the lead wires 2b and 2d, and the electrodes 2c and 2e 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.

[0017] 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). Furthermore, the lead wire 3b is provided with an electrode 3c (third end) that functions as an electrode, and the lead wire 3d is provided with an electrode 3e (fourth end) that functions as an electrode. The coil portion 3a, the lead wires 3b and 3d, and the electrodes 3c and 3e form a single second conductor 3. The lead wires 3b and 3d are also terminals extending from one end of the coil portion 3a, and are therefore also referred to as terminals 3b and 3d.

[0018] 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 between the lead wires 2b and 2d and the electrodes 2c and 2e, 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 between the lead wires 3b and 3d and the electrodes 3c and 3e, are also formed by bending, resulting in a substantially right-angle structure with a radius of curvature. In this manner, 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.

[0019] Coils L1 and L2 are arranged so that their openings overlap. While FIG. 1 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 coil L1 when a current flows from electrode 2c of first conductor 2 in the direction indicated by the arrow (clockwise), and a magnetic field in the same direction as the magnetic field of coil L1 is generated in coil L2 when a current flows from electrode 2e to electrode 3e of second conductor 3. Coils L1 and L2 are electrically connected by a connecting member 5 disposed between electrodes 2e and 3e. However, 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.

[0020] 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, or various resins mixed with metal magnetic material. While the housing 4 is shown in a rectangular parallelepiped shape in FIG. 1, 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 a trapezoid in which the area of ​​the second main surface is larger than that of the first main surface.

[0021] 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.

[0022] 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 5), a coil L1, and a coil L2.

[0023] As shown in FIG. 2 , the capacitor C1 has one end connected to the intermediate terminal T 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.

[0024] 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.

[0025] 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.

[0026] 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, as shown in FIG. 1 , a coil (coil L3) is formed using terminals 2d, 3d, electrodes 2e, 3e, and a connecting member 5, and connected to the capacitor C1. Specifically, the coil L3 is electrically connected to the wiring on the board using the connecting member 5, and is connected to the capacitor C1, which 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. Instead of the connecting member 5, the electrode 2e connected to terminal 2d and the electrode 3e connected to terminal 3d may be connected to the wiring on the board.

[0027] 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 positive coupling coefficient.

[0028] As shown in Figure 2, the coil component 1 has two coils L1 and L2 formed between electrodes 2c and 3c. Each of coils L1 and L2 is a single-turn coil with no 180-degree bends and no overlapping with the coil's own conductor. As a result, the coils do not open due to the springback phenomenon, which would cause the angle between coils L1 and L2 to shift and change the coupling coefficient between the coils, or the spacing between coils L1 and L2 to increase and reduce the coupling coefficient. The single-layer coils L1 and L2 can be stacked in parallel at a constant distance, providing a stable mutual inductance value.

[0029] As shown in Figure 1, the coil portion 2a and the coil portion 3a each have one turn, but by bringing the connection position with the lead wire close, an opening is formed that is as closed as possible. By closing the opening in this way, the magnetic flux density can be increased, and the inductance value of the coil portion 2a and the coil portion 3a can be increased, thereby increasing the mutual inductance value. By covering 80% or more, preferably 90% or more, of the outer periphery of the opening that is surrounded by the inner edges of the coil portion 2a and the coil portion 3a and forms a roughly rectangular shape, the inductance value can be increased and the required mutual inductance value can be obtained even though the coil has one turn.

[0030] The coil component 1 has an opening closed by the coil portion 2a, and then leads out from the side surface by leads 2b and 2d, the distance between which is greater on the second main surface (mounting surface) than on the first main surface (coil surface). This distance relationship makes it possible to close the coil to increase the inductance value, while widening the distance between electrodes on the mounting board (second main surface), and thus suppressing short-circuit defects between adjacent terminals during mounting.

[0031] In the coil component 1, electrodes 2c and 3c are connected to a power supply line. Heat generated from electrodes 2c and 3c connected to the power supply line is dissipated through the power supply path. In contrast, when the coil component 1 is used as a filter circuit, heat generated from electrodes 2e and 3e connected to a capacitor is not directly connected to the power supply path, and therefore is not properly dissipated as it is from the power supply line. In the coil component 1, the metal width of electrode 2e is wider than the width of lead wire 2d drawn from the conductor of coil portion 2a. In the coil component 1, the metal width of electrode 3e is wider than the width of lead wire 3d drawn from the conductor of coil portion 3a. The wider portions of electrodes 2e and 3e are connected to a connecting member 5. This allows for a larger area for dissipating heat generated at electrodes 2e and 3e, thereby improving the heat dissipation performance of the coil component 1.

[0032] In coil component 1, coil L1 and coil L2 are each a single turn, with no connection between the two coils. Therefore, compared to coils formed by bending metal, coil component 1 does not experience springback, which would increase the distance between the coils and reduce the coupling coefficient between the coils. Furthermore, because there are no bent portions with a small radius of curvature, there is no risk of performance degradation due to heat generation or vibration, and the coils do not break at the bent portions. Because coil component 1 is formed from a metal plate and can be manufactured by stamping metal, production costs can be reduced.

[0033] Because the coil component 1 has a single turn, the variation in inductance value caused by the coil can be reduced compared to when a coil is formed from multiple layers of folded metal. When a multiple-layer coil is formed by folding metal, parasitic capacitance occurs within a single coil, and depending on the processing accuracy of the folding, the opening position may shift, causing variation in the inductance value of the coil itself. However, because the coil component 1 is formed from coil portions 2a and 3a with a single turn, no parasitic capacitance occurs within each coil and variation in the inductance value of each coil can be reduced, thereby providing stable mutual inductance and effectively suppressing noise.

[0034] Because the coil component 1 has a single turn, there is no need for a 180-degree bend, as is the case when forming a coil consisting of multiple layers. Although bends occur between the coil 2 a (coil component 3 a) and the lead wires 2 b, 2 d (lead wires 3 b, 3 d) and between the lead wires 2 b, 2 d (lead wires 3 b, 3 d) and the electrodes 2 c, 2 e (electrodes 3 c, 3 e), these are all 90-degree bends, which reduces the impact of springback compared to a 180-degree bend. Furthermore, the radius of curvature can be made relatively large, thereby suppressing the impact of springback. On the other hand, if a multi-layer coil is formed by forming two 90-degree bends spaced apart, the spacing between the coils will be wide, resulting in a lower coupling coefficient and a lower mutual inductance value. However, because the coil component 1 uses a single-turn, single-layer coil, it is possible to provide a coil component with reduced impact of springback.

[0035] Furthermore, by making the distance between the bend between the coil and the lead wire (between coil portion 2a (coil portion 3a) and lead wires 2b, 2d (lead wires 3b, 3d)) and the bend between the lead wire and the electrode (between lead wires 2b, 2d (lead wires 3b, 3d) and electrodes 2c, 2e (electrodes 3c, 3e)) to be at least half the length of the coil opening of the coil component, coil portion 2a and coil portion 3a can be kept sufficiently far from the electrodes and mounting substrate, and the effect of magnetic field blocking by metal contained in the electrodes and mounting substrate can be suppressed, thereby providing a stable, high mutual inductance value.

[0036] <Embodiment 2> In embodiment 2, a configuration will be described in which, compared to embodiment 1, each lead wire is arranged at a position on the side surface of housing 4 and the electrodes at each end are eliminated. Fig. 3A is a perspective view of coil component 1A according to embodiment 2, and 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.

[0037] The first conductor 2 has lead wires 2b and 2d extending from the coil L1 to the rear surface of the housing 4, and the lead wires 2b and 2d also function as electrodes. The second conductor 3 has lead wires 3b and 3d extending from the coil L2 to the front surface of the housing 4, and the lead wires 3b and 3d also function as electrodes.

[0038] 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.

[0039] In the coil component 1A, the positions of the lead wires 2b, 2d, 3b, and 3d can be arranged as shown in Figures 3A and 3B, 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 show the components at right angles as a schematic diagram, the bent portions are arc-shaped because they are formed by bending.

[0040] <Embodiment 3> In embodiment 3, a configuration will be described in which, compared to embodiment 1, each lead wire is arranged at a position on the side surface of housing 4, the width of each lead wire is made constant, and the electrodes at each end are eliminated. 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.

[0041] The first conductor 2 has a lead wire 2b drawn out from the rear surface of the housing 4, and the lead wire 2b also functions as an electrode. The first conductor 2 has a lead wire 2d drawn out from the left side surface of the housing 4, and the lead wire 2d also functions as an electrode. The second conductor 3 has a lead wire 3b drawn out from the front surface of the housing 4, and the lead wire 3b also functions as an electrode. The second conductor 3 has a lead wire 3d drawn out from the right side surface of the housing 4, and the lead wire 3d also functions as an electrode.

[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 1B 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 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.

[0044] By dividing the pull-out surface into adjacent side surfaces in this manner, the effect of parasitic capacitance occurring between pull-out wire 2b (pull-out wire 3b) and pull-out wire 2d (pull-out wire 3d) can be suppressed, and the cancellation of inductance due to current flowing in opposite directions between pull-out wire 2b (pull-out wire 3b) and pull-out wire 2d (pull-out wire 3d) can be suppressed, thereby preventing the inductance value of coil L3 from decreasing.

[0045] <Fourth Embodiment> In the fourth embodiment, a configuration will be described in which, compared to the first embodiment, each lead wire is arranged at a position on the side surface of the housing 4, the width of each lead wire is made constant, and the electrodes at each end are eliminated. Fig. 5 is a perspective view of a coil component 1C 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.

[0046] The first conductor 2 has leads 2b and 2d drawn out from the left side surface of the housing 4, and then the lead 2b is arranged so as to wrap around the rear surface of the housing 4 and the lead 2d is arranged so as to wrap around the front surface of the housing 4, with the lead 2b and 2d also functioning as electrodes. The second conductor 3 has leads 3b and 3d drawn out from the right side surface of the housing 4, and then the lead 3b is arranged so as to wrap around the front surface of the housing 4 and the lead 3d is arranged so as to wrap around the rear surface of the housing 4, with the lead 3b and 3d also functioning as electrodes. Each lead is embedded in the housing 4, with only the portion connected to the mounting board exposed from the housing 4. The portions exposed from the housing 4 are not limited to this, and parts other than the coil portion may be exposed, or electrodes may be formed on the second main surface and parts other than the electrodes may be embedded in the housing 4.

[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 1C 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 1C, the positions of the lead wires 2b, 2d, 3b, and 3d can be arranged as shown in Figure 5, 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 the electrodes at right angles as a schematic diagram, the bent portions are arc-shaped because they are formed by bending.

[0049] <Fifth Embodiment> In the fifth embodiment, a configuration in which the shapes of the lead wires are different from those in the second embodiment will be described. Fig. 6A is a perspective view of a coil component 1D according to the fifth embodiment. Fig. 6B is a right side view of the coil component 1D according to the fifth embodiment. Note that in the coil component 1D shown in the fifth embodiment, the same components as those in the coil component 1A according to the second embodiment are designated by the same reference numerals and detailed description thereof will not be repeated.

[0050] Here, the term "lead-out wires" refers to the portions of the coils L1, L2 arranged parallel to the main surfaces that are bent, and includes those located inside the housing 4. Lead-out wires 2b, 2d are bent once at an upper position inside the housing 4, then bent again at a position close to the lower surface of the housing 4 so as to protrude outside the housing 4, and are connected from that position via bent portions 2f, 2g to electrodes 2c, 2e that continue to the lower surface of the housing 4. Lead-out wires 3b, 3d are bent once at an upper position inside the housing 4, then bent again at a position close to the lower surface of the housing 4 so as to protrude outside the housing 4, and are connected from that position via bent portions 3f, 3g to electrodes 3c, 3e that continue to the lower surface of the housing 4.

[0051] Coils L1 and L2 are connected to electrodes 2e and 3e on the mounting board without using a connecting member. Coils L1 and L2 may be electrically connected between electrodes 2e and 3e via connecting member 5. As shown in Figures 6A and 6B, lead wires 2b, 2d, 3b, and 3d are drawn out from positions near the bottom surface of the side surface of housing 4. Lead wires 2b, 2d, 3b, and 3d may be drawn out from any position on housing 4, and the drawing positions may be changed appropriately depending on the application.

[0052] <Modification 1> Next, a modification of embodiment 5 will be described. Fig. 7A is a perspective view of coil component 1E according to modification 1. Fig. 7B is a plan view of coil component 1E according to modification 1. Fig. 7C is a right side view of coil component 1E according to modification 1. Note that in coil component 1E shown in modification 1, the same components as those in coil component 1E according to embodiment 5 are designated by the same reference numerals and detailed description thereof will not be repeated.

[0053] In coil device 1E, coils L1 and L2 are circular, and the housing 4 that covers coils L1 and L2 is cylindrical. Lead wires 2b and 2d are bent once at an upper position within housing 4 and then bent again at the lower end of housing 4 so as to protrude outside of housing 4, with the re-bent positions forming electrodes 2c and 2e. Lead wires 3b and 3d are bent once at an upper position within housing 4 and then bent again at the lower end of housing 4 so as to protrude outside of housing 4, with the re-bent positions forming electrodes 3c and 3e.

[0054] The coils L1 and L2 are connected to the electrodes 2e and 3e on the mounting substrate without using a connecting member. The coils L1 and L2 may be electrically connected between the electrodes 2e and 3e via a connecting member 5. As shown in FIGS. 7A to 7C , the coils L1 and L2 may have a shape other than rectangular, and the shape of the housing 4 may be changed depending on the shape of the coils L1 and L2. The shape of the housing 4 may be a shape other than a rectangular parallelepiped, cube, or cylinder, and the shape of the internal coils L1 and L2 may be different from that of the housing 4, and the shape may be changed appropriately depending on the application.

[0055] 1 , it has been described that the connecting member 5 is disposed between the electrode 2e and the electrode 3e, and that the coil L1 and the coil L2 are electrically connected by the connecting member 5. However, if the electrode 2e and the electrode 3e are electrically connected in the coil component 1, and an opening is formed by the lead wire 2d, the electrode 2e, the electrode 3e, and the lead wire 3d, the third coil L3 can be formed. In other words, in the coil component 1, the third coil L3 is formed by a current flowing in the direction of the arrow shown in FIG. 1 (counterclockwise) through the opening formed by the lead wire 2d, the electrode 2e, the electrode 3e, and the lead wire 3d, and a magnetic field is generated in the coil L3.

[0056] The configuration in which the electrodes 2e and 3e are electrically connected is not limited to the configuration in which the electrodes 2e and 3e are electrically connected by the connecting member 5, and for example, the electrodes 2e and 3e may be formed from an integrated metal plate. Fig. 8 is a perspective view of a coil component 1F according to Modification 2. Note that in the coil component 1F shown in Fig. 8, the same components as those in the coil component 1 shown in Fig. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated.

[0057] In the coil component 1F shown in Figure 8, the coil L1 including the lead wire 2d and the electrode 2e, and the coil L2 including the lead wire 3d and the electrode 3e are formed from a single metal plate. Therefore, there is no need to provide a connecting member 5 between the electrodes 2e and 3e. If the coils L1 and L2 were formed from a continuous metal plate, the coils L1 and L2 could be formed simply by bending, and problems such as increased resistance at the joints or reduced reliability caused by the connecting member 5 would not occur, resulting in a coil component 1F that can handle large currents despite its small size. Note that if at least the lead wire 2d, the electrode 2e, the electrode 3e, and the lead wire 3d are formed from a single metal plate, there is no need to provide a connecting member 5.

[0058] In coil component 1F, electrode 2e and electrode 3e are electrically connected on the second main surface, but electrode 2e and electrode 3e may be electrically connected on the side surface instead of the second main surface. At least, in coil component 1F, electrodes 2e and electrode 3e are electrically connected so that coil L3 is formed on a surface different from the surface on which the openings of coils L1 and L2 are formed.

[0059] Furthermore, in the coil device 1F, the electrodes 2 e and 3 e are described as being formed from a single metal plate, but the electrodes 2 e or 3 e may be electrically connected by extending them and directly connecting them to the electrodes 3 e or 2 e. When the electrodes 2 e and 3 e are directly connected, the number of joints can be reduced to one, compared to a configuration in which the electrodes 2 e and 3 e are electrically connected by the connecting member 5, and an increase in resistance and a decrease in reliability can be suppressed.

[0060] <Modification 3> In the coil component 1 shown in FIG. 1 , it has been described that the connecting member 5 is disposed between the electrode 2e and the electrode 3e, and that the coil L1 and the coil L2 are electrically connected by the connecting member 5. However, the coil component may be mounted on a circuit board having a wiring pattern that electrically connects the electrode 2e and the electrode 3e, thereby electrically connecting the electrode 2e and the electrode 3e to form the coil L3. FIG. 9A is a schematic diagram illustrating the configuration of a circuit device according to Modification 3. FIG. 9B is a perspective view of the coil component according to Modification 3. Note that in the coil component 1G shown in FIG. 9B , the same components as those in the coil component 1 shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0061] As shown in FIG. 9A , the circuit board 10 is formed with a wiring pattern 51 (first wiring pattern), a wiring pattern 52 (second wiring pattern), a wiring pattern 53 (third wiring pattern), a GND wiring 54, and wiring patterns 61 and 62. The coil component 1G is mounted on the wiring patterns 51 to 53. Specifically, the electrode 2c of the coil component 1G is electrically connected to the wiring pattern 51. The electrode 3c of the coil component 1G is electrically connected to the wiring pattern 52. The electrodes 2e and 3e of the coil component 1G are electrically connected to the wiring pattern 53. The wiring pattern 53 electrically connects the electrode 2e to the electrode 3e and performs the same function as the connecting member 5 shown in FIG. 1 . Therefore, an opening is formed by the lead wire 2d, the electrode 2e, the electrode 3e, and the lead wire 3d shown in FIG. 9B and the wiring pattern 53 shown in FIG. 9A . A current flows through the opening in the direction indicated by the arrow (counterclockwise), forming a third coil L3 and generating a magnetic field in the coil L3.

[0062] Electrode 2e, electrode 3e, and wiring pattern 53 also serve as intermediate terminals T of coils L1 and L2 shown in Fig. 2. Therefore, by mounting capacitor C1 between wiring pattern 61 extending from wiring pattern 53 and wiring pattern 62 extending from GND wiring 54, the circuit device functions as filter circuit 100. Of course, the configuration of the circuit device shown in Fig. 9A is just one example, and the circuit device may be configured without mounting capacitor C1.

[0063] 9B , coil component 1G has electrodes 2c, 2e and electrodes 3c, 3e on the second principal surface, but may have only leads 2b, 2d and leads 3b, 3d on the side surfaces. When a coil component that does not have electrodes 2c, 2e and electrodes 3c, 3e on the second principal surface is mounted on circuit board 10, lead 2b of the coil component is electrically connected to wiring pattern 51, lead 3b to wiring pattern 52, and lead 2d and lead 3d to wiring pattern 53.

[0064] <Aspects> (1) A coil component according to the present disclosure includes a housing having a pair of opposing first and second main surfaces, a first coil section including a first coil disposed inside the housing and substantially parallel to the first main surface, a first lead wire and a second lead wire connected to ends of the first coil, 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, and a second coil section including a third lead wire and a fourth lead wire connected to ends of the second coil, respectively. The first coil has one turn and does not have a portion overlapping with other portions of the first coil when viewed from the first main surface. The second coil has one turn and does not have a portion overlapping with other portions of the second coil when viewed from the first main surface. First bends are provided between the first coil and the first lead wire, between the first coil and the second lead wire, between the second coil and the third lead wire, and between the second coil and the fourth lead wire. The first and second lead lines are arranged such that the distance between them on the first main surface side is shorter than the distance between them on the second main surface side. The third and fourth lead lines are arranged such that the distance between them on the first main surface side is shorter than the distance between them on the second main surface side. The first, second, third, and fourth lead lines are shaped so that their width on the second main surface side is wider than their width on the first main surface side.

[0065] According to the coil component of the present disclosure, the first coil and the second coil can function as a single-turn coil without bending, thereby forming a stable mutual inductance value. Furthermore, the influence of parasitic inductance and parasitic capacitance of the electrode portion caused by the lead wires being too close to each other can be reduced. Furthermore, the heat dissipation performance of the coil component can be improved.

[0066] (2) In the coil component according to (1), the area of ​​the coil opening formed by the inner edge of the first coil that can be covered by the inner edge of the first coil is 80% or more, and the area of ​​the coil opening formed by the inner edge of the second coil that can be covered by the inner edge of the second coil is 80% or more. This allows the coil opening to be made large.

[0067] (3) In the coil component according to (1) or (2), the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire extend from the first coil or the second coil along a side surface connecting the first main surface and the second main surface, thereby improving the degree of freedom in arranging the lead wires.

[0068] (4) In the coil component according to any one of (1) to (3), the first coil and the second coil are disposed closer to the first main surface than the center of the housing, and the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire extend from the first main surface side of the housing toward the second main surface, thereby improving the degree of freedom in arranging the lead wires.

[0069] (5) In the coil component according to any one of (1) to (4), the first coil, the first lead wire, and the second lead wire are formed from a single metal wire, a single metal plate, or a collection of multiple metal wires, and the second coil, the third lead wire, and the fourth lead wire are formed from a single metal wire, a single metal plate, or a collection of multiple metal wires, and the first bent portion is formed by bending. This makes it possible to provide a coil component with reduced effects of springback.

[0070] (6) In the coil component according to any one of (1) to (5), the first bent portion has a substantially right-angled structure with a radius of curvature. This makes it possible to provide a coil component that is less susceptible to springback compared to a coil component bent 180 degrees.

[0071] (7) In the coil component according to any one of (1) to (6), the second lead wire and the fourth lead wire are arranged on surfaces that face each other, thereby improving the degree of freedom in arranging the lead wires.

[0072] (8) The coil component according to any one of (1) to (7), further comprising a first end portion connected to the first lead wire and formed on the second main surface, a second end portion connected to the second lead wire and formed on the second main surface, a third end portion connected to the third lead wire and formed on the second main surface, and a fourth end portion connected to the fourth lead wire and formed on the second main surface, thereby allowing each end portion to function as an electrode on the second main surface.

[0073] (9) In the coil component according to (8), the first coil, the first lead wire, the second lead wire, the first end, and the second end are formed from one metal plate, one metal wire, or a plurality of metal wires, and the second coil, the third lead wire, the fourth lead wire, the third end, and the fourth end are formed from one metal plate, one metal wire, or a plurality of metal wires, and second bent portions are formed by bending between the first lead wire and the first end, between the second lead wire and the second end, between the third lead wire and the third end, and between the fourth lead wire and the fourth end. This makes it possible to provide a coil component with reduced effects of springback.

[0074] (10) In the coil component according to (9), the second bent portion has a substantially orthogonal structure with a curvature radius. This makes it possible to provide a coil component with reduced effects of springback compared to a coil component bent 180 degrees.

[0075] (11) The coil component according to any one of (8) to (10), wherein the widths of the second end and the fourth end are greater than the widths of the first coil and the second coil, thereby improving the heat dissipation performance of the coil component.

[0076] (12) In the coil component according to (9) or (10), the distance between the first bent portion formed by the first coil and the first lead wire and the second bent portion formed by the first lead wire and the first end portion is longer than half the length of the short side of the first main surface, thereby providing a coil component with reduced effects of springback.

[0077] (13) In the coil component according to any one of (1) to (12), the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are arranged on the outer side of the casing, thereby improving the degree of freedom in arranging the lead wires.

[0078] (14) In the coil component according to any one of (1) to (12), the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are arranged inside the housing, thereby improving the degree of freedom in arranging the lead wires.

[0079] (15) Another coil component of the present disclosure includes a housing having a pair of first and second principal surfaces facing each other, a first coil section including a first coil disposed inside the housing and substantially parallel to the first principal surface, first and second lead wires connected to respective ends of the first coil, 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 principal surface, a second coil section including third and fourth lead wires connected to respective ends of the second coil, a first end connected to the first lead wire and formed on the second principal surface, a second end connected to the second lead wire and formed on the second principal surface, a third end connected to the third lead wire and formed on the second principal surface, and a fourth end connected to the fourth lead wire and formed on the second principal surface. The first coil does not have a portion overlapping with other portions of the first coil when viewed from the first principal surface, and has one turn. The second coil has one turn when viewed from the first main surface, and does not have any overlapping portions with other portions of the second coil. First bends are provided between the first coil and the first lead wire, between the first coil and the second lead wire, between the second coil and the third lead wire, and between the second coil and the fourth lead wire. The second end and the fourth end are electrically connected. This improves the heat dissipation performance of the coil component.

[0080] (16) In the coil component according to (15), the second end and the fourth end are electrically connected via a connecting member, thereby improving the heat dissipation performance of the coil component.

[0081] (17) A filter circuit according to the present disclosure includes the coil component according to any one of (8) to (12), (15), and (16), and a capacitor electrically connecting the second end and the fourth end of the coil component. This allows the filter circuit to have high noise removal performance.

[0082] (18) A circuit device according to the present disclosure includes a coil component and a circuit board on which the coil component is mounted. The coil component includes: a housing having a pair of first and second main surfaces facing each other; a first coil section disposed within the housing and substantially parallel to the first main surface, the first coil section having a first lead wire and a second lead wire connected to ends of the first coil; a second coil disposed within the housing such that an opening of the first coil overlaps an opening of the first coil when viewed from the direction of the first main surface; and a second coil section having a third lead wire and a fourth lead wire connected to ends of the second coil. The first coil has one turn and does not have a portion overlapping with other portions of the first coil when viewed from the first main surface, and the second coil has one turn and does not have a portion overlapping with other portions of the second coil when viewed from the first main surface, and has first bends between the first coil and the first lead-out wire, between the first coil and the second lead-out wire, between the second coil and the third lead-out wire, and between the second coil and the fourth lead-out wire. The circuit board includes a first wiring pattern electrically connected to the first lead-out wire, a second wiring pattern electrically connected to the third lead-out wire, and a third wiring pattern electrically connected to the second and fourth lead-out wires and electrically connecting the second and fourth lead-out wires.

[0083] 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.

[0084] 1, 1A, 1B, 1C coil component, 2 first conductor, 3 second conductor, 2a, 3a coil portion, 2b, 2d, 3b, 3d lead wire, 2c, 2e, 3c, 3e electrode, 4 housing, 5 connecting member, L1, L2, L3 coil, S1, S2 opening.

Claims

1. a housing having a pair of first and second main surfaces opposed to each other; a first coil section disposed inside the housing and including a first coil disposed substantially parallel to the first main surface, and a first lead wire and a second lead wire respectively connected to ends of the first coil; a second coil portion including a second coil disposed inside the housing such that an opening of the second coil overlaps an opening of the first coil when viewed from the first main surface, and a third lead wire and a fourth lead wire respectively connected to ends of the second coil, the first coil has one turn when viewed from the first main surface, and does not have a portion that overlaps with other portions of the first coil; the second coil has one turn when viewed from the first main surface, and does not have a portion that overlaps with other portions of the second coil; a first bent portion is provided between the first coil and the first lead wire, between the first coil and the second lead wire, between the second coil and the third lead wire, and between the second coil and the fourth lead wire; The first lead-out line and the second lead-out line are the first lead-out line and the second lead-out line are wired such that a distance between the first lead-out line and the second lead-out line on the first main surface side is shorter than a distance between the first lead-out line and the second lead-out line on the second main surface side; The third lead-out line and the fourth lead-out line are the third lead line and the fourth lead line are wired such that a distance between the third lead line and the fourth lead line on the first main surface side is shorter than a distance between the third lead line and the fourth lead line on the second main surface side; A coil component in which the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are shaped so that the width on the second main surface side is wider than the width on the first main surface side.

2. an area that can be covered by the inner edge of the first coil with respect to a coil opening formed by the inner edge of the first coil is 80% or more; The coil component according to claim 1 , wherein an area of ​​a coil opening formed by the inner edge of the second coil that can be covered by the inner edge of the second coil is 80% or more.

3. 3. The coil component according to claim 1, wherein the first lead-out wire, the second lead-out wire, the third lead-out wire, and the fourth lead-out wire extend from the first coil or the second coil along a side surface connecting the first main surface and the second main surface.

4. 3. The coil component according to claim 1, wherein the first coil and the second coil are arranged on the first main surface side from a center of the housing, and the first lead-out wire, the second lead-out wire, the third lead-out wire, and the fourth lead-out wire extend from the first main surface side from the center of the housing toward the second main surface.

5. the first coil, the first lead wire, and the second lead wire are formed of one metal wire, one metal plate, or a collection of a plurality of metal wires; the second coil, the third lead wire, and the fourth lead wire are each formed of one metal wire, one metal plate, or a collection of a plurality of metal wires; The coil component according to claim 1 , wherein the first bent portion is formed by bending.

6. The coil component according to claim 1 , wherein the first bent portion has a substantially right-angled structure having a radius of curvature.

7. The coil component according to claim 1 , wherein the second lead wire and the fourth lead wire are disposed on surfaces opposing each other.

8. a first end portion connected to the first lead line and formed on the second main surface; a second end portion connected to the second lead line and formed on the second main surface; a third end portion connected to the third lead line and formed on the second main surface; The coil component according to claim 1 , further comprising: a fourth end portion connected to the fourth lead wire and formed on the second main surface.

9. the first coil, the first lead wire, the second lead wire, the first end, and the second end are formed of one metal plate, one metal wire, or a plurality of metal wires; the second coil, the third lead wire, the fourth lead wire, the third end, and the fourth end are formed of one metal plate, one metal wire, or a plurality of metal wires; 9. The coil component according to claim 8, wherein second bent portions are formed by bending between the first lead-out wire and the first end portion, between the second lead-out wire and the second end portion, between the third lead-out wire and the third end portion, and between the fourth lead-out wire and the fourth end portion.

10. The coil component according to claim 9 , wherein the second bent portion has a substantially orthogonal structure having a radius of curvature.

11. The coil component according to claim 8 , wherein a width of the second end and a width of the fourth end are greater than a width of the first coil and a width of the second coil.

12. 10. The coil component according to claim 9, wherein a distance between the first bent portion formed by the first coil and the first lead wire and the second bent portion formed by the first lead wire and the first end portion is longer than half the length of a short side of the first main surface.

13. The coil component according to claim 1 , wherein the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are arranged on outer sides of side surfaces of the housing.

14. The coil component according to claim 1 , wherein the first lead wire, the second lead wire, the third lead wire, and the fourth lead wire are disposed inside the housing.

15. a housing having a pair of first and second main surfaces opposed to each other; a first coil section disposed inside the housing and including a first coil disposed substantially parallel to the first main surface, and a first lead wire and a second lead wire respectively connected to ends of the first coil; a second coil section including a second coil disposed inside the housing such that an opening of the second coil overlaps an opening of the first coil when viewed from the first main surface, and a third lead wire and a fourth lead wire respectively connected to ends of the second coil; a first end portion connected to the first lead line and formed on the second main surface; a second end portion connected to the second lead line and formed on the second main surface; a third end portion connected to the third lead line and formed on the second main surface; a fourth end portion connected to the fourth lead line and formed on the second main surface; the first coil has one turn when viewed from the first main surface, and does not have a portion that overlaps with other portions of the first coil; the second coil has one turn when viewed from the first main surface, and does not have a portion that overlaps with other portions of the second coil; a first bent portion is provided between the first coil and the first lead wire, between the first coil and the second lead wire, between the second coil and the third lead wire, and between the second coil and the fourth lead wire; The second end and the fourth end are electrically connected to each other.

16. The coil component according to claim 15 , wherein the second end and the fourth end are electrically connected to each other via a connecting member.

17. The coil component according to any one of claims 8, 15, and 16; a capacitor electrically connected to the second end and the fourth end.