Circuit arrangement and filter circuit

Abstract

The present disclosure provides a circuit device and a filter circuit capable of implementing a filter circuit using a coil component that is low in manufacturing cost and stable in mutual inductance. A circuit device (10) includes a coil component (1) and a substrate (60). The coil component (1) includes a first coil (L1), a second coil (L2) having an opening overlapping the opening of the first coil (L1), a terminal (6a) connected to one end of the first coil (L1), a terminal (6b) connected to the other end of the first coil (L1), a terminal (6c) connected to one end of the second coil (L2), and a terminal (6d) connected to the other end of the second coil (L2). The substrate (60) includes: a power line (8a) electrically connected to the terminal (6a); a power line (8b) electrically connected to the terminal (6d); and a wiring (8c) electrically connected to the terminal (6b) and the terminal (6c). The wiring (8c) is also electrically connected to the capacitor (C1).

Description

Technical Field

[0001] The present disclosure relates to a circuit device and a filter circuit equipped with a coil component. Background Art

[0002] In an electronic device, a filter circuit is used to remove unwanted noise components in a current flowing through a conductor. In a filter circuit for noise countermeasures, for example, an EMI (Electro-Magnetic Interference) removal filter or the like is provided, and a capacitor is used as a capacitive element. Therefore, it is known that the noise suppression effect of the filter circuit is degraded due to the equivalent series inductance (ESL) which is the parasitic inductance of the capacitor.

[0003] There is known a technique in which a negative inductance generated by magnetically coupling two coils cancels out the equivalent series inductance ESL of a capacitor, thereby widening the noise suppression effect of the filter circuit over a wide frequency band (for example, Patent Document 1).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2001-160728 SUMMARY OF THE UTILITY MODEL

[0007] Problems to be Solved by the Utility Model

[0008] However, in order to obtain a negative inductance, it is necessary to set the directions of the currents flowing through the two magnetically coupled coils to be the same direction. In the case of two coils that achieve magnetic coupling using a coil component formed by winding a wire around a bobbin, if the terminals of the same flange portion of two wires wound in the same direction are electrically connected to each other as an intermediate terminal, like the structure of a normal transformer coil or a common mode choke coil (CMCC), the directions of the currents are opposite, and a negative inductance cannot be obtained.

[0009] Therefore, with respect to this coil component in which the intermediate terminal is formed on the same flange portion, after winding the wire around the bobbin from the input terminal to the intermediate terminal, it is necessary to change the setting and wind the wire around the bobbin from the intermediate terminal to the output terminal to form it, which causes a problem of increased manufacturing cost. In addition, in a coil component with a small number of turns, as long as two wires are wound around the bobbin in the same direction, it is relatively easy to keep the coil interval constant. However, in a coil component in which the wire is wound around the bobbin in two steps with a change in setting, it is difficult to keep the coil interval constant, and there is a problem of unstable mutual inductance.

[0010] Accordingly, an object of the present disclosure is to provide a circuit device and a filter circuit that can implement a filter circuit using a coil component with a relatively low manufacturing cost and stable mutual inductance.

[0011] Solution to the Problem

[0012] A circuit device according to an aspect of the present disclosure includes a coil component and a substrate on which the coil component is mounted. The coil component includes: a first coil; a second coil, the opening of which overlaps the opening of the first coil when viewed from the opening direction of the first coil; a first terminal connected to one end of the first coil; a second terminal connected to the other end of the first coil; a third terminal connected to one end of the second coil; and a fourth terminal connected to the other end of the second coil. The direction of the magnetic field generated in the first coil when current flows from the first terminal to the second terminal is the same as the direction of the magnetic field generated in the second coil when current flows from the third terminal to the fourth terminal. The substrate includes: a first wiring electrically connected to the first terminal; a second wiring electrically connected to the fourth terminal; and a third wiring electrically connected to the second terminal and the third terminal. The third wiring is also electrically connected to a capacitor, and at least a part of the third wiring is disposed outside the space sandwiched by the plane including the opening of the first coil and the plane including the opening of the second coil.

[0013] Alternatively, the shape of the coil component when viewed from a direction perpendicular to the substrate is rectangular, the first terminal to the fourth terminal are provided on the same plane of the coil component, and the terminals are arranged such that the direction from the first terminal to the second terminal intersects the direction from the third terminal to the fourth terminal.

[0014] Alternatively, the capacitor is connected in series with the third wiring, and the substrate further includes a fourth wiring electrically connected to the capacitor on the side opposite to the side where the capacitor is electrically connected to the third wiring, and the fourth wiring is grounded.

[0015] Alternatively, the opening directions of the first coil and the second coil are perpendicular to the arrangement direction of the capacitor.

[0016] Alternatively, the third wiring includes a portion that linearly connects the connection portion of the third wiring to the second terminal and the connection portion of the third wiring to the third terminal when viewed from a direction perpendicular to the substrate.

[0017] Alternatively, the coil component includes: a bobbin having a main body portion around which a wire is wound and flange portions provided at both ends of the main body portion; a first wire wound around the main body portion to form the first coil; and a second wire wound around the main body portion to form the second coil, and the first terminal to the fourth terminal are formed on the flange portions.

[0018] Alternatively, the opening directions of the first coil and the second coil may be parallel to the surface of the substrate for mounting the coil component.

[0019] Alternatively, the first wire and the second wire may be wound in the same direction.

[0020] Alternatively, the number of turns of the first wire and the number of turns of the second wire may be one turn.

[0021] Alternatively, the coil component may include: a housing; the first coil disposed inside the housing; and the second coil disposed inside the housing such that the opening of the second coil overlaps the opening of the first coil when viewed from the direction of the first main surface of the housing. The first coil has a first terminal led out from the first side surface side of the housing and a second terminal led out from the second side surface side. The second coil has a third terminal led out from the first side surface side of the housing and a fourth terminal led out from the second side surface side. The first terminal and the third terminal extend along the first side surface side toward the second main surface of the housing, and the second terminal and the fourth terminal extend along the second side surface side toward the second main surface of the housing.

[0022] Alternatively, the surface including the openings of the first coil and the second coil may face the surface of the substrate for mounting the coil component.

[0023] Alternatively, the first coil may be integrally formed with the first terminal and the second terminal, and the second coil may be integrally formed with the third terminal and the fourth terminal.

[0024] A filter circuit according to an aspect of the present disclosure includes: the above-described circuit device; and the capacitor electrically connected to the third wiring of the circuit device.

[0025] Effects of the utility model

[0026] According to an aspect of the present disclosure, since the circuit device includes the third wiring electrically connected to the second terminal and the third terminal of the coil component, and the third wiring is also electrically connected to the capacitor, a filter circuit using a coil component with a relatively low manufacturing cost and stable mutual inductance can be realized. Description of the drawings

[0027] Figure 1 is a top view of the circuit device of Embodiment 1.

[0028] Figure 2 is a perspective view of the coil component of Embodiment 1.

[0029] Figure 3It is a circuit diagram of the filter circuit of Embodiment 1.

[0030] Figure 4 It is a top view of the circuit device of Modification 1-1.

[0031] Figure 5 It is a top view of the circuit device of Modification 1-2.

[0032] Figure 6 It is a perspective view of the circuit device of Modification 2.

[0033] Figure 7 It is a perspective view of the coil component of Modification 3.

[0034] Figure 8 It is a side view of the coil component of Modification 3.

[0035] Figure 9 It is a top view of the circuit device of Embodiment 2.

[0036] Figure 10 It is a perspective view of the coil component of Embodiment 2. Detailed Embodiments

[0037] <Embodiment 1>

[0038] The circuit device of Embodiment 1 will be described below. Figure 1 It is a top view of the circuit device 10 of Embodiment 1. This circuit device 10 is, for example, a filter circuit for noise countermeasures for power supply lines 8a and 8b, and is equipped with a coil component 1 that includes two coils magnetically coupled to eliminate the parasitic inductance of capacitor C1. Of course, the circuit device 10 is not limited to a filter circuit for noise countermeasures for power supply lines 8a and 8b, and can also be a filter circuit for noise countermeasures for other signal lines, etc.

[0039] The coil component 1 installed in the circuit device 10 is formed by winding two wire materials in the same direction on a bobbin as described later. Therefore, compared with the case where the wire materials are wound on the bobbin in such a way that the winding direction from the input terminal to the intermediate terminal and the winding direction from the intermediate terminal to the output terminal are opposite directions, the coil component 1 can wind the two wire materials together, so the manufacturing cost is lower. In addition, since the coil component 1 winds the two wire materials in the same direction on the bobbin, it is relatively easy to keep the coil interval constant and the mutual inductance stable. In addition, the coil component 1 is described by taking the winding coil with wire materials wound on the bobbin as an example, but it can also be a coil component with other structures.

[0040] Since the coil component 1 winds two wire materials in the same direction on the bobbin, it has a terminal 6a (first terminal) connected to one end of the first wire material 4, a terminal 6b (second terminal) connected to the other end of the first wire material 4, a terminal 6c (third terminal) connected to one end of the second wire material 5, and a terminal 6d (fourth terminal) connected to the other end of the second wire material 5. That is, the coil component 1 has four terminals from terminal 6a to terminal 6d. The four terminals (terminals 6a to 6d) are provided at the four corners of the coil component 1. In addition, the first wire material 4 wound around the bobbin forms a first coil L1, and the second wire material 5 wound around the bobbin forms a second coil L2.

[0041] In a filter circuit, a coil component for eliminating the parasitic inductance of a capacitor only needs to functionally have three terminals (input terminal, intermediate terminal, output terminal). However, in ordinary electronic components, from the viewpoint of ease of manufacture, a rectangular parallelepiped shape is mostly adopted. In this coil component, the shape is also set to a rectangular parallelepiped. From the viewpoint of mechanical strength, it mostly has four terminals without other connected terminals (NC (non-connected: Non-Connection) terminals). Even if a coil component with four terminals is formed by adding NC terminals, since only three terminals are functionally used, the orientation of the coil component becomes a problem when the coil component is mounted on the substrate 60. Therefore, it is necessary to provide a direction indication mark on the coil component, and it is necessary to align the direction of the coil component during characteristic screening and winding, etc., which becomes a major cause of increased manufacturing cost. On the other hand, since the coil component 1 of the first embodiment does not require NC terminals, the orientation does not become a problem as described later.

[0042] In addition, as Figure 1 shown, the shape of the coil component 1 observed from a direction perpendicular to the substrate 60 is rectangular. The terminals 6a to 6d are provided on the same plane of the coil component 1. The terminals 6a to 6d are arranged such that the direction from terminal 6a to terminal 6b intersects the direction from terminal 6c to terminal 6d.

[0043] The circuit device 10 forms wiring patterns of power supply lines 8a and 8b on the surface of the substrate 60, and the coil component 1 is serially mounted with respect to the power supply lines 8a and 8b. An electrode 7a (first electrode) is provided on the power supply line 8a (first wiring), and the electrode 7a (first electrode) is electrically connected to the terminal 6a of the coil component 1 and is used to input current from the power supply line 8a to the coil component 1. The terminal 6a electrically connected to the electrode 7a functions as an input terminal of the coil component 1. On the other hand, an electrode 7d (fourth electrode) is provided on the power supply line 8b (second wiring), and the electrode 7d (fourth electrode) is electrically connected to the terminal 6d of the coil component 1 and is used to output current from the coil component 1 to the power supply line 8b. The terminal 6d electrically connected to the electrode 7d functions as an output terminal of the coil component 1.

[0044] The substrate 60 is formed by laminating a plurality of insulating layers, and is formed of, for example, low-temperature co-fired ceramics, glass epoxy resin, etc. Electrodes for connecting wiring patterns such as a power supply line 8a, components such as a coil component 1 and a capacitor C1, etc. are formed on the surface of the substrate 60, and are respectively formed of metal materials commonly used such as Cu, Ag, Al, etc. as electrode materials. For example, when the substrate 60 is glass epoxy resin, a wiring pattern is formed of Cu on the glass epoxy resin, and an insulating resin is further formed on the glass epoxy resin including the wiring pattern. The electrode for electrically connecting components such as the mounted coil component 1 and capacitor C1 and the wiring pattern is a portion formed by removing the insulating resin on the wiring pattern. The electrode formed on the wiring pattern is, for example, a portion where the Cu of the wiring pattern and the terminal of the component are electrically connected by solder.

[0045] Furthermore, in the circuit device 10, the capacitor C1 is connected in series with terminals 6b and 6c that function as intermediate terminals of the coil component 1. A wiring 8c (third wiring) is formed on the substrate 60, and this wiring 8c (third wiring) linearly connects an electrode 7b (second electrode) for connecting the terminal 6b and an electrode 7c (third electrode) for connecting the terminal 6c. By wiring 8c to connect the terminals 6b and 6c at the shortest distance as Figure 1 described above, compared with the case where the wiring connected to the terminal 6b and the wiring connected to the terminal 6c are connected by another wiring, parasitic inductance can be reduced, and most of the negative mutual inductance generated in the coil component 1 can be used for canceling the parasitic inductance. By changing the wiring distance (not shown) connecting the terminals 6b and 6c, the parasitic inductance can be increased or decreased, and thus the negative mutual inductance of the entire circuit can be adjusted.

[0046] An electrode 7e (fifth electrode) for electrically connecting to the capacitor C1 is formed on the wiring 8c. In Figure 1 the circuit device 10 shown, the shape of the wiring 8c as viewed from a direction perpendicular to the substrate 60 is in the shape of the letter T. Specifically, when viewed from a direction perpendicular to the substrate 60, the wiring 8c is formed of the following two parts to form the shape of the letter T: a part that linearly connects the connection part (electrode 7b) of the wiring 8c and the terminal 6b and the connection part (electrode 7c) of the wiring 8c and the terminal 6c, and a part that extends from the central part of the linearly connected part to the connection part (electrode 7e) of the capacitor C1. That is, the wiring direction of the part of the wiring 8c connecting the capacitor C1 is perpendicular to the wiring direction of the part of the wiring 8c that linearly connects the electrode 7b and the electrode 7c. In addition, the part of the wiring 8c connecting the capacitor C1 and the part of the wiring 8c that linearly connects the electrode 7b and the electrode 7c can be integrally formed or can be formed separately.

[0047] Therefore, since the wiring direction of the portion of the wiring 8c connecting the capacitor C1 is perpendicular to the opening directions of the first coil L1 and the second coil L2, the opening directions of the first coil L1 and the second coil L2 are perpendicular to the arrangement direction of the capacitor C1 (the direction connecting between the electrodes of the capacitor C1). Since the capacitor C1 is not arranged in the direction of the magnetic fields generated by the first coil L1 and the second coil L2, the influence of the capacitor C1 on the magnetic fields of the first coil L1 and the second coil L2 can be reduced. In addition, since the coil component 1 is a small chip component, heat dissipation from the side of the mounting substrate 60 is generally dominant. Therefore, the heat dissipation performance from the coil component 1 can be improved by using the wiring 8c arranged in a manner that straddles the terminals 6b and 6c that function as the intermediate terminals of the coil component 1, and the current flowing in the coil component 1 itself can be increased. From the perspective of heat dissipation, the width B of the wiring 8c can be twice the width A of the electrode 7b or the electrode 7c. The larger the width B of the wiring 8c, the better the heat dissipation performance, but the distance between the coil component 1 and the capacitor C1 becomes longer, and the parasitic inductance caused by the wiring from the coil component 1 to the capacitor C1 increases. Therefore, the width B of the wiring 8c is preferably about 1.3 to 4 times the width A of the electrode 7b or the electrode 7c.

[0048] Although, as described above, the heat dissipation performance is improved by increasing the width B of the wiring 8c, it is not possible to arrange components other than the coil component 1 and the capacitor C1, and the design freedom of the substrate 60 is reduced. Since the coils included in the coil component 1 are designed to allow a constant current to flow through, heat generation is not particularly a problem, but the path of the current flowing from the electrode 7c provided on the substrate 60 through the wiring 8c to the electrode 7b becomes a problem of heat generation. Therefore, it is only necessary to take heat dissipation measures for the interval between the electrode 7c and the electrode 7b. That is, in Figure 1 the case of the T-shaped wiring 8c as shown, it is preferable that the length b of the portion of the wiring 8c connected to the capacitor C1 is longer than the distance a between the electrode 7c and the electrode 7b. On the other hand, it is preferable that the length b of the portion of the wiring 8c connected to the capacitor C1 is shorter than the length c of the coil component 1. Compared with the case of increasing the width B of the wiring 8c, a space can be ensured to freely arrange components in the left-right direction in the figure of the capacitor C1. In addition, the same can also be applied to the wiring 8c1 shown in Figure 4 and the wiring 8c2 shown in Figure 5 .

[0049] The capacitor C1 is connected in series with the wiring 8c and is connected to the wiring 8d (the fourth wiring) on the side opposite to the side electrically connected to the wiring 8c. An electrode 7f for electrically connecting to the capacitor C1 is formed on the wiring 8d. The wiring 8d is grounded via the ground electrode 70. By installing the capacitor C1 between the wiring 8c and the wiring 8d, the terminals 6b and 6c between the two coils (the first coil L1 and the second coil L2) included in the coil component 1 and the ground electrode 70 (GND) are electrically connected. The ground electrode 70 is an electrode electrically connected to the ground potential and is constituted by, for example, a conductive path electrically connected to the ground potential disposed in the inner layer of the substrate 60.

[0050] Next, the coil component 1 mounted on the circuit device 10 will be described. Figure 2 FIG. is a perspective view of the coil component 1 of the first embodiment. The coil component 1 includes a bobbin 2, a first wire 4, and a second wire 5. The bobbin 2 has a main body portion 2a around which the wire is wound and flange portions 2b and 2c provided at both ends of the main body portion 2a. The bobbin 2 is made of a non-conductive material, specifically, a non-magnetic material such as alumina, a magnetic material such as Ni-Zn ferrite, or a resin. Further, in the case where the bobbin 2 is made of a resin, it is constituted by, for example, a resin containing magnetic powder such as metal powder and ferrite powder, a resin containing non-magnetic powder such as silica powder, or a resin not containing fillers such as powder.

[0051] When the size of the coil component 1 is 2.0 mm × 1.25 mm, the main body portion 2a of the bobbin 2 is a square column of 1.0 mm × 1.0 mm. Further, although the main body portion 2a is described as a square column in the present disclosure, the main body portion 2a may also be a cylindrical column or a polygonal column. In the coil component 1, the first wire 4 and the second wire 5 are directly wound around the main body portion 2a. Further, the first wire 4 and the second wire 5 are, for example, copper wires.

[0052] In order to stabilize the mutual inductance in the coil component 1, it is necessary to keep the opening diameters of the first coil L1 and the second coil L2 and the coil interval between the first coil L1 and the second coil L2 constant. Therefore, the first wire 4 and the second wire 5 are wound around the main body portion 2a in the same direction at the same time to form the coil component 1. And, as Figure 2As shown, the first wire 4 is wound around the main body 2a for one turn to form the first coil L1, and the second wire 5 is wound around the main body 2a for one turn to form the second coil L2. Strictly speaking, the first wire 4 is wound from the terminal 6a to the terminal 6b for 3 / 4 of a turn covering three faces of the main body 2a, and the second wire 5 is wound from the terminal 6c to the terminal 6d for 5 / 4 of a turn covering five faces of the main body 2a. Here, winding a wire around the main body 2a for one turn means that the number of turns of the wire wound around the main body 2a is one turn, and it also includes cases where the amount of wire wound around the main body 2a is 3 / 4 of a turn or 5 / 4 of a turn.

[0053] Next, the terminals for fixing the first wire 4 and the terminals for fixing the second wire 5 will be described. As Figure 2 shown, terminals 6a, 6b connected to the ends of the first wire 4 and terminals 6c, 6d connected to the ends of the second wire 5 are provided on the flange portions 2b, 2c provided on both sides of the bobbin 2. Specifically, terminals 6a, 6c are provided on the flange portion 2b, and terminals 6b, 6d are provided on the flange portion 2c.

[0054] Ag paste is baked on the terminals 6a to 6d, for example, and Ni plating and Sn plating are performed. Therefore, the ends of the first wire 4 are attached to the terminals 6a, 6b, and the ends of the second wire 5 are attached to the terminals 6c, 6d, and hot press bonding or laser welding is performed to fix the wire and the terminals respectively. Of course, the fixing method of the wire and the terminals is not limited to this, and a fixing method using metal terminal crimping, riveting, or soldering can also be adopted. Moreover, laser welding can also be performed on the basis of fixing the wire and the terminals by using metal terminal riveting.

[0055] Regarding the coil component 1, among the terminals 6a to 6d provided on the same surface of the coil component 1, the position of the terminal 6a provided on the flange portion 2b and the position of the terminal 6d provided on the flange portion 2c are on the same side ( Figure 1 the upper side in Figure 2 ). Therefore, the first wire 4 and the second wire 5 wound in the same direction around the main body 2a are connected to the terminals 6a to 6d as Figure 1 shown, so that the first coil L1 and the second coil L2 are arranged crosswise as

[0056] shown. As long as the first coil L1 and the second coil L2 are arranged crosswise so that current can flow from either of the terminals 6a, 6b to the first coil L1, and current can flow from either of the terminals 6c, 6d to the second coil L2, there is no characteristic difference caused by the orientation of the coil component 1. That is, when the coil component 1 is mounted on the substrate 60, the orientation of the coil component 1 is not a problem. Therefore, there is no need to provide a direction indication mark on the coil component 1, and there is no need to align the direction of the coil component during characteristic screening and winding, etc., which can reduce the manufacturing cost.

[0057] Specifically, when the orientation of the coil component 1 is rotated by 180 degrees ( Figure 1 as shown in the parentheses), the terminal 6b of the coil component 1 is electrically connected to the power supply line 8a, the terminal 6c of the coil component 1 is electrically connected to the power supply line 8b, and the terminals 6a and 6d function as intermediate terminals of the coil component 1 and are connected to the electrodes 7b and 7c of the wiring 8c. In addition, since the first coil L1 and the second coil L2 are arranged crosswise, the terminals 6a and 6b serving as input terminals and the terminals 6d and 6c serving as output terminals are arranged linearly as Figure 1 shown, and thus it is easy to use when connecting the input terminals and the output terminals to other devices.

[0058] In addition, when the coil component 1 is mounted on the substrate 60, the opening directions of the first coil L1 and the second coil L2 are parallel to the surface of the substrate 60 on which the coil component 1 is mounted.

[0059] Figure 3 is a circuit diagram of the filter circuit 100 of Embodiment 1. Specifically, the filter circuit 100 is an EMI removal filter circuit and is a third-order T-type LC filter circuit. In addition, although a third-order T-type LC filter circuit is used to illustrate the structure of the filter circuit 100 in the present disclosure, the same structure can also be applied to a fifth-order T-type LC filter circuit, a higher-order T-type LC filter circuit. First, as Figure 3 shown, the filter circuit 100 includes a coil component 1 and a capacitor C1.

[0060] As Figure 3 shown, the capacitor C1 is connected in series between the terminals 6b and 6c serving as intermediate terminals and the ground electrode (GND). The capacitor C1 may be one, but in the case of in-vehicle applications, etc., two capacitors may be connected in series to form a redundant circuit structure.

[0061] In addition, the capacitor C1 may be not only a multilayer ceramic capacitor having BaTiO 3 (barium titanate) as a main component, but also a multilayer ceramic capacitor having other materials as a main component, or may not be a multilayer ceramic capacitor, for example, an aluminum electrolytic capacitor or other types of capacitors.

[0062] The capacitor C1 connected to the coil component 1 has an inductor L3 as a parasitic inductance (equivalent series inductance (ESL)). Therefore, as Figure 3 shown, the filter circuit 100 is equivalent to a circuit structure in which the inductor L3 and the capacitor C1 are connected in series.

[0063] In addition to the capacitor C1, the first coil L1 and the second coil L2 are also connected to the terminals 6b and 6c. The first coil L1 and the second coil L2 are magnetically coupled to generate a negative inductance component (mutual inductance M). This negative inductance component can be used to cancel the parasitic inductance (inductor L3) of the capacitor C1, and the inductance component of the capacitor C1 can be apparently reduced. Additionally, in Figure 3 the mutual inductance M (-M) for canceling the inductor L3 is connected in series with the capacitor C1, and is illustrated as an equivalent circuit that applies the mutual inductance M (+M) to the first coil L1 and the second coil L2 respectively.

[0064] The filter circuit 100 composed of the capacitor C1, the first coil L1, and the second coil L2 uses the negative inductance component generated by the mutual inductance M between the first coil L1 and the second coil L2 to cancel the parasitic inductance of the capacitor C1, thereby improving the noise suppression effect in the high-frequency band.

[0065] In addition, since the parasitic inductance generated by the wiring 8c that electrically connects the terminals 6b and 6c of the coil component 1 is generated in series with the capacitor C1 and the inductor L3 that is the parasitic inductance of the capacitor C1, the parasitic inductance can be changed by changing the length of the wiring 8c, so that the inductor L3 can be adjusted to cancel the mutual inductance M.

[0066] As described above, the circuit device 10 of the first embodiment includes the coil component 1 and the substrate 60 on which the coil component 1 is mounted. The coil component 1 includes: the first coil L1; the second coil L2, when viewed from the opening direction of the first coil L1, the opening of the second coil L2 overlaps the opening of the first coil L1; the terminal 6a, which is connected to one end of the first coil L1; the terminal 6b, which is connected to the other end of the first coil L1; the terminal 6c, which is connected to one end of the second coil L2; and the terminal 6d, which is connected to the other end of the second coil L2. When current flows from the terminal 6a to the terminal 6b, the direction of the magnetic field generated in the first coil L1 is the same as the direction of the magnetic field generated in the second coil L2 when current flows from the terminal 6c to the terminal 6d. The substrate 60 includes the power supply line 8a electrically connected to the terminal 6a, the power supply line 8b electrically connected to the terminal 6d, and the wiring 8c electrically connected to the terminals 6b and 6c. The wiring 8c is also electrically connected to the capacitor C1.

[0067] Thus, the circuit device 10 of the first embodiment includes the wiring 8c electrically connected to the terminals 6b and 6c of the coil component 1, and the wiring 8c is also electrically connected to the capacitor C1, so that the filter circuit 100 using the coil component 1 with a lower manufacturing cost and stable mutual inductance can be realized.

[0068] In addition, the filter circuit 100 of Embodiment 1 includes the above-described circuit device 10 and a capacitor C1 electrically connected to the wiring 8c of the circuit device 10. Thus, the filter circuit 100 can cancel the parasitic inductance of the capacitor C1 and improve the noise suppression effect in the high-frequency band.

[0069] <Modified Example 1>

[0070] In Figure 1 the circuit device 10 shown, the case where the shape of the wiring 8c is in the shape of the letter T is described, but it is not limited thereto, and the portion of the wiring connecting the capacitor C1 may be provided at a portion of the wiring 8c other than the central portion. Figure 4 is a top view of the circuit device 10A of Modified Example 1-1. Figure 5 is a top view of the circuit device 10B of Modified Example 1-2. In addition, in Figure 4 and Figure 5 the circuit devices 10A and 10B shown, the same structural components as those of the circuit device 10 shown in Figure 1 are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0071] In Figure 4 the circuit device 10A shown, the shape of the wiring 8c1 as viewed in the direction perpendicular to the substrate 60 is in the shape of the letter L. Specifically, the wiring 8c1 is formed in the shape of the letter L by the portion of the wiring connecting the capacitor C1 extending from the long side on the electrode 7c side of the portion of the wiring that linearly connects the electrodes 7b and 7c. The capacitor C1 is connected in series with the wiring 8c1 and is electrically connected to the wiring 8d on the side opposite to the side electrically connected to the wiring 8c1. In addition, the wiring 8c1 may also be formed in the shape of the letter L by the portion of the wiring connecting the capacitor C1 extending from the long side on the electrode 7b side of the portion of the wiring that linearly connects the electrodes 7b and 7c.

[0072] In Figure 5 the circuit device 10B shown, the shape of the wiring 8c2 as viewed in the direction perpendicular to the substrate 60 is in the shape of the letter I. Specifically, the wiring 8c2 is formed in the shape of the letter I by the portion of the wiring connecting the capacitor C1 extending from the short side on the electrode 7b side of the portion of the wiring that linearly connects the electrodes 7b and 7c. The capacitor C1 is connected in series with the wiring 8c2 and is electrically connected to the wiring 8d on the side opposite to the side electrically connected to the wiring 8c2. In addition, the wiring 8c2 may also be formed in the shape of the letter I by the portion of the wiring connecting the capacitor C1 extending from the short side on the electrode 7c side of the portion of the wiring that linearly connects the electrodes 7b and 7c.

[0073] As Figure 4 and Figure 5As shown, the portion of the wiring connecting the capacitor C1 can be connected to various portions. Therefore, the position where the capacitor C1 is mounted can be freely changed, and thus the design freedom of the assembly manufacturer adopting the circuit device is increased.

[0074] <Modified Example 2>

[0075] Regarding the circuit device 10, the case where the coil component 1 and the capacitor C1 are mounted on the substrate 60 on which the power supply lines 8a, 8b, the wirings 8c, 8d are formed as shown has been described, but it is not limited thereto, and a relay substrate provided with power supply lines and wirings may be mounted on the coil component and used as one component. Figure 1 is a perspective view of the circuit device of Modified Example 2. In the circuit device 10C shown in Figure 6 the same reference numerals are given to the same structures as those of the circuit device 10 shown in Figure 6 and the detailed description thereof is omitted. Figure 1 In the circuit device 10C shown in

[0076] Figure 6 a relay substrate 62 on which the power supply lines 8a, 8b and the wiring 8c are formed is mounted on the surface of the coil component 1 provided with the terminals 6a to 6d as one component. The power supply lines 8a, 8b and the wiring 8c are formed on the surface of the relay substrate 62 in contact with the coil component 1, and electrodes electrically connected to the power supply lines 8a, 8b and the wiring 8c by through electrodes (not shown) are formed on the back surface of the relay substrate 62.

[0077] Specifically, electrodes 80a electrically connected to the power supply line 8a by through electrodes, electrodes (not shown) electrically connected to the power supply line 8b by through electrodes, and an electrode 80c electrically connected to the wiring 8c by through electrodes are formed on the back surface of the relay substrate 62. The electrode 80a is connected to the power supply line of the device on which the circuit device 10C is mounted, and the electrode 80c is connected to the capacitor C1.

[0078] <Modified Example 3>

[0079] In the foregoing Embodiment 1, as shown in Figure 2 the coil component 1 has been described as having a structure in which the first wire 4 and the second wire 5 are wound around the bobbin 2. However, the coil component mounted on the circuit device 10 is not limited to a coil component in which a wire is wound around a bobbin, and for example, it may also be a coil component having a structure in which a coil formed of a metal plate or a metal wire is molded with resin. Figure 7 is a perspective view of the coil component 1A of Modified Example 3. Figure 8 is a side view of the coil component 1A of Modified Example 3. Further, Figure 8 (a) of Figure 8 is a side view of the X-Z plane of the coil component 1A, and

[0080] The coil component 1A includes a coil portion 4a (first coil L1) and a coil portion 5a (second coil L2) in the housing 9. The coil portion 4a has a rectangular opening and is disposed inside the housing 9 substantially parallel to the main surface 90A (first main surface). In addition, the coil portion 4a is formed into a spiral structure wound 1.5 turns by blanking a metal plate and making a part thereof inclined, and the portion led out from the side surface 91 (first side surface) of the housing 9 constitutes a terminal 6a (first terminal), and the portion led out from the side surface 92 (second side surface) constitutes a terminal 6b (second terminal). The coil portion 5a has a rectangular opening and is disposed above the coil portion 4a inside the housing 9 substantially parallel to the main surface 90A. In addition, the coil portion 5a is formed into a spiral structure wound 1.5 turns by blanking a metal plate and making a part thereof inclined, and the portion led out from the side surface 91 of the housing 9 constitutes a terminal 6c (third terminal), and the portion led out from the side surface 92 constitutes a terminal 6d (fourth terminal).

[0081] The terminals 6a to 6d are provided on the main surface 90B and are arranged on the same plane of the coil component 1A. The terminals 6a to 6d are arranged such that the direction from the terminal 6a to the terminal 6b intersects with the direction from the terminal 6c to the terminal 6d. That is, the arrangement of the terminals 6a to 6d on the main surface 90B is a staggered arrangement. When the coil component 1A is mounted on the substrate 60 in such a manner that the terminals 6a to 6d provided on the main surface 90B are electrically connected to the electrodes 7a to 7d provided on the substrate 60, the opening directions of the coil portions 4a and 5a are perpendicular to the substrate 60 and are also perpendicular to the arrangement relationship of the capacitor C1, where the capacitor C1 is connected to the terminal 6c of the coil portion 4a and the terminal 6d of the coil portion 5a.

[0082] The housing 9 fixes the relative positions of the coil portion 4a and the coil portion 5a and is made of, for example, a molded resin. Specifically, the molded resin is made of an epoxy resin, a silicone resin, a liquid crystal polymer, or various resins mixed with a metal magnetic material, to which a silica filler is added.

[0083] In addition, the coil portion 4a and the terminals 6a and 6b may be formed of a single metal plate or a single metal wire, or may be formed of separate metal plates or metal wires. Similarly, the coil portion 5a and the terminals 6c and 6d may be integrally formed of a single metal plate or a single metal wire, or may be formed of separate metal plates or metal wires.

[0084] <Embodiment 2>

[0085] In Embodiment 1, a structure in which the connection positions of both ends of the first coil L1 and the connection positions of both ends of the second coil L2 in the coil component 1 mounted on the circuit device 10 cross each other has been described, but it is not limited thereto. In Embodiment 2, Figure 9 A structure in which the connection positions of both ends of the first coil L1 and the connection positions of both ends of the second coil L2 in the coil component do not cross each other is described, and it is a top view of the circuit device 10D of Embodiment 2. In addition, in Figure 9 the circuit device 10D shown, the same reference numerals are assigned to the same components as those in Figure 1 the circuit device 10 shown, and detailed descriptions are not repeated.

[0086] In Figure 9 the circuit device 10D shown, the structure of the coil component 1B mounted on the substrate 60 is different. Specifically, the coil component 1B has a terminal 6a (first terminal) connected to one end of the first wiring 4B constituting the first coil L1, a terminal 6c (second terminal) connected to the other end of the first wiring 4B, a terminal 6b (third terminal) connected to one end of the second wiring 5B constituting the second coil L2, and a terminal 6d (fourth terminal) connected to the other end of the second wiring 5B. The first wiring 4B of the first coil L1 is connected to the electrode 7a and the electrode 7c provided on the substrate 60, and the second wiring 5B of the second coil L2 is connected to the electrode 7b and the electrode 7d. Therefore, the coil component 1B has a configuration in which the connection positions of both ends of the first coil L1 and the connection positions of both ends of the second coil L2 do not cross each other.

[0087] The coil component 1B may have a structure in which a first wire and a second wire are wound around a bobbin, or may have a structure in which a coil formed of a metal plate or a metal wire is molded with resin. Figure 10 It is a perspective view of the coil component 1B of Embodiment 2. In addition, in Figure 10 the coil component 1B shown, the same reference numerals are assigned to the same components as those in Figure 7 the coil component 1A shown, and detailed descriptions are not repeated.

[0088] The coil component 1B includes a coil portion 4b (first coil L1) and a coil portion 5b (second coil L2) in the housing 9. The coil portion 4b has a rectangular opening and is buried in the housing 9 substantially parallel to the main surface 90A (first main surface). In addition, a part of the coil portion 4b drawn out from the side surface 91 (first side surface) of the housing 9 constitutes the terminal 6a, and another part constitutes the terminal 6c. In addition, the coil portion 4b, the terminal 6a, and the terminal 6c are formed by punching a metal plate and correspond to Figure 9 the first wiring 4B shown.

[0089] The coil portion 5b has a rectangular opening and is disposed inside the housing 9 above the coil portion 4a substantially parallel to the main surface 90A. Further, a part of the coil portion 5a led out from the side surface 92 of the housing 9 constitutes the terminal 6b, and another part constitutes the terminal 6d. Additionally, the coil portion 5b, the terminal 6b, and the terminal 6d are formed by blanking a metal plate and correspond to the second wiring 5B shown in Figure 9 The second wiring 5B shown in

[0090] The terminals 6a to 6d are provided on the main surface 90B. The terminals 6a to 6d provided on the main surface 90B are electrically connected to the electrodes 7a to 7d provided on the substrate 60. In the coil component 1B, the terminals 6a to 6d are arranged on the main surface 90B such that the direction from the terminal 6a to the terminal 6c does not cross the direction from the terminal 6d to the terminal 6b. Therefore, in the circuit device 10D formed by combining the substrate 60 and the coil component 1B, the coil component 1B can be mounted on the substrate 60 regardless of the orientation of the coil component 1B, and a filter circuit using negative mutual inductance can be constituted.

[0091] <Mode>

[0092] (1) The circuit device of the present disclosure includes a coil component and a substrate on which the coil component is mounted. The coil component includes: a first coil; a second coil, the opening of which overlaps the opening of the first coil when viewed from the opening direction of the first coil; a first terminal connected to one end of the first coil; a second terminal connected to the other end of the first coil; a third terminal connected to one end of the second coil; and a fourth terminal connected to the other end of the second coil. When current flows from the first terminal to the second terminal, the direction of the magnetic field generated in the first coil is the same as the direction of the magnetic field generated in the second coil when current flows from the third terminal to the fourth terminal. The substrate includes: a first wiring electrically connected to the first terminal; a second wiring electrically connected to the fourth terminal; and a third wiring electrically connected to the second terminal and the third terminal, and the third wiring is also electrically connected to a capacitor.

[0093] Since the circuit device of the present disclosure includes a third wiring electrically connected to the second terminal and the third terminal of the coil component, and the third wiring is also electrically connected to a capacitor, a filter circuit using a coil component with a relatively low manufacturing cost and stable mutual inductance can be realized.

[0094] (2) In the circuit device according to (1), the shape of the coil component when viewed from a direction perpendicular to the substrate is rectangular, the first terminal to the fourth terminal are provided on the same plane of the coil component, and the terminals are arranged such that the direction from the first terminal to the second terminal crosses the direction from the third terminal to the fourth terminal. Thereby, the first coil and the second coil can be arranged in a crossed manner.

[0095] (3) The circuit device according to (1) or (2), wherein the capacitor is connected in series with the third wiring, and the substrate further includes a fourth wiring that is electrically connected to the capacitor on the side opposite to the side where the capacitor is electrically connected to the third wiring, and the fourth wiring is grounded. Thus, a filter circuit can be formed.

[0096] (4) The circuit device according to any one of (1) to (3), wherein the opening directions of the first coil and the second coil are perpendicular to the arrangement direction of the capacitor. Thus, the influence of the capacitor C1 on the magnetic fields of the first coil and the second coil can be reduced.

[0097] (5) The circuit device according to any one of (1) to (4), wherein the third wiring includes a portion that linearly connects the connection portion of the third wiring and the second terminal and the connection portion of the third wiring and the third terminal when viewed from a direction perpendicular to the substrate. Thus, a filter circuit using a coil component with stable mutual inductance can be realized.

[0098] (6) The circuit device according to any one of (1) to (5), wherein the coil component includes: a bobbin having a main body portion for winding a wire and flange portions provided at both ends of the main body portion; a first wire wound around the main body portion for forming the first coil; and a second wire wound around the main body portion for forming the second coil, and the first terminal to the fourth terminal are formed on the flange portions. Thus, a filter circuit using a wound coil can be realized.

[0099] (7) The circuit device according to (6), wherein the opening directions of the first coil and the second coil are parallel to the surface of the substrate for mounting the coil component. Thus, the influence of the capacitor C1 on the magnetic fields of the first coil and the second coil can be reduced.

[0100] (8) The circuit device according to (6) or (7), wherein the first wire and the second wire are wound in the same direction. Thus, the mutual inductance can be adjusted using the winding direction of the wire.

[0101] (9) The circuit device according to any one of (6) to (8), wherein the number of turns of the first wire and the number of turns of the second wire are one turn. Thus, the inductances of the two coils can be adjusted using the number of turns of the first wire and the second wire.

[0102] (10) The circuit device according to any one of (1) to (5), wherein the coil component includes: a housing; a first coil disposed inside the housing and disposed substantially parallel to the first main surface of the housing; and a second coil disposed inside the housing such that the opening overlaps the opening of the first coil when viewed from the direction of the first main surface. The first coil has a first terminal led out from the first side surface side of the housing and a second terminal led out from the second side surface side. The second coil has a third terminal led out from the first side surface side of the housing and a fourth terminal led out from the second side surface side. The first terminal and the third terminal extend along the first side surface toward the second main surface, and the second terminal and the fourth terminal extend along the second side surface toward the second main surface.

[0103] (11) The circuit device according to (10), wherein the opening directions of the first coil and the second coil are perpendicular to the surface of the substrate for mounting the coil component.

[0104] (12) The circuit device according to (10) or (11), wherein the first coil is integrally formed with the first terminal and the second terminal, and the second coil is integrally formed with the third terminal and the fourth terminal.

[0105] (13) The filter circuit of the present disclosure includes: the circuit device according to any one of (1) to (12); and a capacitor electrically connected to the third wiring of the circuit device. Thus, the filter circuit of the present disclosure can cancel the parasitic inductance of the capacitor and improve the noise suppression effect in the high frequency band.

[0106] It should be considered that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present disclosure is represented by the claims, rather than by the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0107] Description of Reference Numerals

[0108] 1. Coil component; 2. Coil bobbin; 2a. Main body portion; 2b, 2c. Flange portions; 4. First wire; 5. Second wire; 6a - 6d. Terminals; 7a - 7f, 80a, 80d. Electrodes; 8a, 8b. Power supply wires; 8c, 8c1, 8c2, 8d. Wirings; 10, 10A - 10C. Circuit devices; 60. Substrate; 62. Relay substrate; 70. Ground electrode; 100. Filter circuit.

Claims

1. A circuit device, characterized in that, the circuit device includes: a coil component; and a substrate for mounting the coil component, the coil component includes: a first coil; a second coil, the opening of which overlaps the opening of the first coil when viewed from the opening direction of the first coil; a first terminal connected to one end of the first coil; a second terminal connected to the other end of the first coil; a third terminal connected to one end of the second coil; and a fourth terminal connected to the other end of the second coil, when current flows from the first terminal to the second terminal, the direction of the magnetic field generated in the first coil is the same as the direction of the magnetic field generated in the second coil when current flows from the third terminal to the fourth terminal, the substrate includes: a first wiring electrically connected to the first terminal; a second wiring electrically connected to the fourth terminal; and a third wiring electrically connected to the second terminal and the third terminal, the third wiring is also electrically connected to a capacitor, and at least a part of the third wiring is disposed outside the space sandwiched by the plane including the opening of the first coil and the plane including the opening of the second coil.

2. The circuit device according to claim 1, characterized in that, the shape of the coil component when viewed from the direction perpendicular to the substrate is rectangular, the first terminal to the fourth terminal are provided on the same plane of the coil component, each terminal is arranged such that the direction from the first terminal to the second terminal intersects the direction from the third terminal to the fourth terminal.

3. The circuit device according to claim 1 or 2, characterized in that, the capacitor is connected in series with the third wiring, the substrate further includes a fourth wiring electrically connected to the capacitor on the side opposite to the side where the capacitor is electrically connected to the third wiring, the fourth wiring is grounded.

4. The circuit device according to claim 1 or 2, characterized in that, the opening directions of the first coil and the second coil are perpendicular to the arrangement direction of the capacitor.

5. The circuit device according to claim 1 or 2, characterized in that, the third wiring includes a part that linearly connects the connection part of the third wiring and the second terminal and the connection part of the third wiring and the third terminal when viewed from the direction perpendicular to the substrate.

6. The circuit device according to claim 1 or 2, characterized in that, the coil component includes: a bobbin having a main body portion for winding a wire and flange portions provided at both ends of the main body portion; a first wire wound around the main body portion for forming the first coil; and a second wire wound around the main body portion for forming the second coil, the first terminal to the fourth terminal are formed on the flange portions.

7. The circuit device according to claim 6, characterized in that, the opening directions of the first coil and the second coil are parallel to the surface of the substrate for mounting the coil component.

8. The circuit device according to claim 6, characterized in that, The first wire and the second wire are wound in the same direction.

9. The circuit device according to claim 6, characterized in that the number of turns of the first wire and the number of turns of the second wire are one turn.

10. The circuit device according to claim 1 or 2, characterized in that the coil component includes: a housing; the first coil disposed inside the housing; and the 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 direction of the first main surface of the housing, the first coil has the first terminal led out from the first side surface side of the housing and the second terminal led out from the second side surface side, the second coil has the third terminal led out from the first side surface side of the housing and the fourth terminal led out from the second side surface side, the first terminal and the third terminal extend along the first side surface side toward the second main surface of the housing, the second terminal and the fourth terminal extend along the second side surface side toward the second main surface.

11. The circuit device according to claim 10, characterized in that a surface including the openings of the first coil and the second coil faces a surface of the substrate for mounting the coil component.

12. The circuit device according to claim 10, characterized in that the first coil is integrally formed with the first terminal and the second terminal, and the second coil is integrally formed with the third terminal and the fourth terminal.

13. A filter circuit, characterized in that the filter circuit includes: the circuit device according to claim 1 or 2; and the capacitor electrically connected to the third wiring of the circuit device.

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