Circuit device and circuit board

Abstract

The present disclosure provides: a circuit device capable of discharging heat from a coil component; and a circuit board. A filter circuit (100) according to the present disclosure comprises: a circuit board (10) in which power supply wirings (51, 52) are arranged; a coil component (1) electrically connected to the power supply wirings (51, 52); and a capacitor (C1) electrically connected to the coil component (1). The circuit board (10) includes the power supply wiring (51) electrically connected to an electrode (2c), a power supply wiring (52) electrically connected to an electrode (3c), and an intermediate wiring (60) for electrically connecting an intermediate terminal and one end of the capacitor (C1). The intermediate wiring (60) has a third portion (63) and a fourth portion (64) that extend in the wiring direction of the power supply wirings (51, 52). The length of the intermediate wiring (60) in the extending direction of the intermediate wiring (60) is longer than the length of the coil component (1).

Description

Circuit device and circuit board

[0001] The present disclosure relates to a circuit device and a circuit board.

[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 in which the equivalent series inductance ESL of a capacitor is cancelled out by the negative inductance generated by magnetically coupling two coils, thereby broadening the bandwidth of the noise suppression effect of a filter circuit (for example, Japanese Patent Laid-Open No. 2001-160728: Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2001-160728

[0005] When the coil component described in JP 2001-160728 A (Patent Document 1) is used in a filter circuit, the coil component itself generates heat due to the current flowing through the power line because it is connected in series to the power line. While large electronic components such as active components can be provided with heat dissipation means such as heat dissipation electrodes, small electronic components such as passive components measuring a few millimeters square cannot be provided with heat dissipation means such as heat dissipation electrodes due to limitations on component size. In particular, in circuit devices incorporating coil components such as filter circuits, a configuration that can efficiently dissipate heat from the coil component is desired.

[0006] Therefore, an object of the present disclosure is to provide a circuit device and a circuit board that can dissipate heat from a coil component.

[0007] A circuit device according to one embodiment of the present disclosure includes a circuit board on which a plurality of wirings are arranged, a coil component electrically connected to the plurality of wirings, and a capacitor element electrically connected to the coil component. The coil component includes a first coil and a second coil, with one end of the first coil defined as a first terminal, one end of the second coil defined as a second terminal, and a portion connecting the other end of the first coil to the other end of the second coil defined as an intermediate terminal. The circuit board includes a first wiring electrically connected to the first terminal, a second wiring electrically connected to the second terminal, and an intermediate wiring electrically connecting the intermediate terminal to one end of the capacitor element. The intermediate wiring has a portion extending along the wiring direction of at least one of the first wiring and the second wiring, and the length of the intermediate wiring in the extension direction of the intermediate wiring is longer than the length of the coil component.

[0008] Another circuit device according to one embodiment of the present disclosure includes a circuit board on which a plurality of wirings are arranged, a coil component electrically connected to the plurality of wirings, and a capacitor element electrically connected to the coil component. The coil component includes a first coil and a second coil, with one end of the first coil defined as a first terminal, one end of the second coil defined as a second terminal, and a portion connecting the other end of the first coil to the other end of the second coil defined as an intermediate terminal. The circuit board includes a first wiring electrically connected to the first terminal, a second wiring electrically connected to the second terminal, and an intermediate wiring electrically connecting the intermediate terminal to one end of the capacitor element. The intermediate wiring has a portion extending in a width direction perpendicular to the wiring direction of the first wiring and the second wiring, and the portion is disposed between the first wiring and the second wiring.

[0009] A circuit board according to one embodiment of the present disclosure is a circuit board capable of mounting a coil component having a plurality of wirings arranged thereon and electrically connecting the plurality of wirings and a capacitor element electrically connected to the coil component. The circuit board includes a first wiring electrically connecting to a first terminal of a first coil included in the coil component, a second wiring electrically connecting to a second terminal of a second coil included in the coil component, and an intermediate wiring electrically connecting an intermediate terminal connecting the first coil and the second coil to one end of the capacitor element. The intermediate wiring has a portion extending along the wiring direction of at least one of the first wiring and the second wiring, and the length of the intermediate wiring in the extension direction of the intermediate wiring is longer than the length of the coil component.

[0010] Another circuit board according to an embodiment of the present disclosure is a circuit board capable of mounting a coil component having a plurality of wirings arranged thereon and electrically connecting the plurality of wirings and a capacitor element electrically connected to the coil component. The circuit board includes a first wiring electrically connecting to a first terminal of a first coil included in the coil component, a second wiring electrically connecting to a second terminal of a second coil included in the coil component, and an intermediate wiring electrically connecting an intermediate terminal connecting the first coil and the second coil to one end of the capacitor element. The intermediate wiring has a portion extending in a width direction perpendicular to the wiring direction of the first wiring and the second wiring, and the portion is disposed between the first wiring and the second wiring.

[0011] According to the circuit device and circuit board according to the present disclosure, heat from the coil component mounted on the circuit board can be efficiently released to the wiring.

[0012] 1 is a schematic diagram of a filter circuit according to a first embodiment. 2 is a circuit diagram of the filter circuit according to the first embodiment. 3 is a perspective view of a coil component mounted in the filter circuit according to the first embodiment. 4 is a diagram for explaining the flow of heat in the coil component according to the first embodiment. 5 is a schematic diagram of a circuit board according to the first embodiment. 6 is a schematic diagram of a filter circuit according to a modified example of the first embodiment. 7 is a schematic diagram of a filter circuit according to a second embodiment. 8 is a schematic diagram of a filter circuit according to a modified example of the second embodiment. 9 is a schematic diagram of a filter circuit according to a third embodiment.

[0013] In the circuit device according to the present disclosure, a power supply filter circuit in which a coil component, which is an example of a passive component, is mounted on a circuit board will be described with reference to the drawings. Note that the circuit device is not limited to a filter circuit, and can be similarly applied to any circuit device that requires heat dissipation from a coil component to wiring on a circuit board.

[0014] First Embodiment First, a filter circuit according to the first embodiment and a coil component mounted in the filter circuit will be described with reference to the drawings. Fig. 1 is a schematic diagram of a filter circuit 100 according to the first embodiment. Fig. 2 is a circuit diagram of the filter circuit 100 according to the first embodiment. Fig. 3 is a perspective view of a coil component 1 mounted in the filter circuit 100 according to the first embodiment. Note that with respect to the X-axis, Y-axis, and Z-axis defined in Fig. 3, the X-axis direction represents the left-right direction of the coil component 1, the Y-axis direction represents the front-rear direction of the coil component 1, and the Z-axis direction represents the up-down direction of the coil component 1, respectively.

[0015] The coil component 1 is, for example, a transformer coil mounted in a filter circuit 100 used to suppress noise in power supply wiring. As will be described later, the coil component 1 magnetically couples two coils (coil L1 and coil L2) to cancel the parasitic inductance of a capacitor mounted in the filter circuit 100.

[0016] As shown in FIG. 1 , a circuit board 10 is mounted with a power supply 20, a power supply IC 30 serving as a power supply circuit, and a filter circuit 100 disposed between the power supply 20 and the power supply IC 30. The circuit board 10 shown in FIG. 1 is an example, and the power supply 20 may be a battery, a connection terminal for connecting to an external power supply, or a power supply circuit that boosts or drops voltage. The power supply IC 30 may be a power supply circuit that boosts or drops voltage, or a power supply circuit such as a converter. Furthermore, the filter circuit 100 may be a circuit that is powered by power from the power supply 20, rather than the power supply IC 30. The filter circuit 100 may be disposed anywhere on the circuit board 10, as long as it is disposed so as to remove unnecessary components between the input and output.

[0017] The filter circuit 100 includes a coil component 1, a capacitor C1 serving as a capacitance element, and an intermediate wiring 60 electrically connecting the coil component 1 and the capacitor C1. An electrode 2c (first terminal) of the coil component 1 is electrically connected to a power supply 20 via a power supply wiring 51 (first wiring). Meanwhile, an electrode 3c (second terminal) of the coil component 1 is electrically connected to a power supply IC 30 via a power supply wiring 52 (second wiring). Electrodes 2e and 3e of the coil component 1 are intermediate terminals T of the two coils and are electrically connected by a first portion 61 of the intermediate wiring 60. The intermediate terminal T is connected to a GND wiring 53 via the intermediate wiring 60 and the capacitor C1. The electrode 2e may be considered a first intermediate terminal, and the electrode 3e may be considered a second intermediate terminal. The intermediate wiring 60 has second to fourth portions 62 to 64 to improve the heat dissipation of the coil component 1, as described below. Being electrically connected refers to a state in which electrical continuity is achieved using wiring, solder mounting, wire, etc., and includes cases in which wiring and coil components are directly connected, as well as cases in which a conductive member is sandwiched between them.

[0018] 2, the filter circuit 100 is an EMI removal filter and is a third-order T-type LC filter circuit. This filter circuit 100 connects electrode 2c to power supply 20 and electrode 3c to power supply IC 30. The filter circuit 100 passes necessary components of the current flowing from power supply 20 to power supply IC 30 and removes unnecessary components. This filter circuit 100 uses capacitor C1, which is a capacitance element, and therefore uses negative inductance generated by the magnetic coupling of two coils to cancel the equivalent series inductance ESL (La) of the capacitor.

[0019] In the following embodiments, a third-order T-type LC filter circuit will be used as the configuration of the filter circuit 100, but coil components of a similar configuration can also be applied to a fifth-order T-type LC filter circuit or a higher-order T-type LC filter circuit. As shown in Figure 2, the filter circuit 100 includes a capacitor C1, electrodes 2c and 3c, an intermediate terminal T (electrodes 2e and 3e), a coil L1, and a coil L2.

[0020] 2, one end of the capacitor C1 is connected to the intermediate terminal T, and the other end is connected to the GND wiring 53. The capacitor C1 is made of BaTiO ３ The present invention is not limited to multilayer ceramic capacitors primarily composed of barium titanate (barium titanate), but may also include multilayer ceramic capacitors primarily composed of other materials, or other types of capacitors other than multilayer ceramic capacitors, such as aluminum electrolytic capacitors. Capacitor C1 has an inductor La as a parasitic inductance (equivalent series inductance (ESL)), and is equivalent to a circuit configuration in which inductor La is connected in series with capacitor C1a. Capacitor C1 may also be equivalent to a circuit configuration in which parasitic resistance (equivalent series resistance (ESR)) is connected in series with inductor La and capacitor C1a.

[0021] In addition to capacitor C1, coils L1 and L2 are also connected to intermediate terminal T. Coils L1 and L2 are additively connected and magnetically coupled, generating a negative inductance component in the path from intermediate terminal T to GND. This negative inductance component can be used to cancel out the parasitic inductance (inductor La) of capacitor C1, thereby making the inductance component of capacitor C1 appear smaller. In other words, filter circuit 100, which is composed of capacitor C1, coil L1, and coil L2, can suppress a decrease in noise removal effect in the high frequency band due to the parasitic inductance of capacitor C1 by canceling out the parasitic inductance of capacitor C1 with the negative inductance component due to the mutual inductance between coils L1 and L2, thereby improving noise suppression effect in the high frequency band.

[0022] Specifically, as shown in Fig. 3, the coil component 1 includes a coil L1 (first coil), a coil L2 (second coil), and a housing 4. The coil L1 and the coil L2 are formed from a metal plate, for example, copper or an alloy of copper and other metals. The coil L1 and the coil L2 formed from the metal plate are covered with an insulating material (not shown). Specifically, the insulating material covering the coil L1 and the coil L2 is a resin such as polyimide or epoxy.

[0023] The coil L1 includes a coil portion 2a having a rectangular opening, a terminal 2b (first terminal) extending from one end of the coil portion 2a, and a terminal 2d (second terminal) extending from the other end of the coil portion 2a. The coil portion 2a is disposed inside the housing 4 parallel to the main surface 40A (first main surface). While the coil portion 2a is illustrated as a single-turn coil, it may be a multi-turn coil. The terminals 2d and 2d are drawn out from the side surface 41 (first side surface) of the housing 4 and extend along the side surface 41 toward the main surface 40B (second main surface). The terminal 2b shown in FIG. 1 extends to the main surface 40B, and the portion of the terminal 2d that contacts the main surface 40B constitutes an electrode 2c. The terminal 2d extends to the main surface 40B, and the portion of the terminal 2d that contacts the main surface 40B constitutes an electrode 2e. When the coil component 1 is mounted on the circuit board 10 , the electrode 2 c is electrically connected to a first portion 61 of an intermediate wiring 60 on the circuit board 10 .

[0024] The coil L2 includes a coil portion 3a having a rectangular opening, a terminal 3b (third terminal) extending from one end of the coil portion 3a, and a terminal 3d (fourth terminal) extending from the other end of the coil portion 3a. The coil portion 3a is disposed above the coil portion 2a inside the housing 4, parallel to the main surface 40A. Although the coil portion 3a is illustrated as a single-turn coil, it may be a multi-turn coil. The terminals 3d and 3d are drawn out from the side surface 42 (second side surface) of the housing 4 and extend along the side surface 42 toward the main surface 40B. The terminal 3b shown in FIG. 1 extends to the main surface 40B, and the portion of the terminal 3d that contacts the main surface 40B constitutes an electrode 3c. The terminal 3d extends to the main surface 40B, and the portion of the terminal 3d that contacts the main surface 40B constitutes an electrode 3e. When the coil component 1 is mounted on the circuit board 10, the electrode 3c is electrically connected to the first portion 61 of the intermediate wiring 60 on the circuit board 10. The electrodes 2e and 3e are electrically connected by a first portion 61 of an intermediate wiring 60 disposed on the circuit board 10. By connecting the electrodes 2e and 3e by the first portion 61 of the intermediate wiring 60, the coils L1 and L2 are connected in series, and the electrodes 2e and 3e form an intermediate terminal T between the coils L1 and L2.

[0025] When the terminal 2b of the coil L1 is connected to the power supply 20 via the electrode 2c, a current flows in the coil portion 2a in a clockwise direction. The current that flows in the coil portion 2a flows counterclockwise through the terminal 2d, the electrode 2e, the first portion 61 of the intermediate wiring 60, the electrode 3e, and the terminal 3d, in that order. For the coil L2, a current flows from the terminal 3d to the coil portion 3a in a clockwise direction. Therefore, a magnetic field is generated in the coil portion 2a in the direction from the main surface 40A to the main surface 40B (-Z direction). Furthermore, a magnetic field is generated in the coil portion 3a in the direction from the main surface 40A to the main surface 40B (-Z direction). Because the coil portions 2a and 3a are arranged so as to overlap when viewed from the main surface 40A direction, the coils L1 and L2 are magnetically coupled.

[0026] The housing 4 fixes the relative positions of the coil L1 and the coil L2 and is made of, for example, molded resin. Specifically, the molded resin is made of epoxy resin with added silica filler, silicone resin, liquid crystal polymer, or various resins mixed with metal magnetic material. The housing 4 has a side surface 41 (first side surface) and a side surface 42 (second side surface) that face each other, and the side surface closer to the terminal 2b (first terminal) is called a side surface 43 (third side surface), and the side surface closer to the terminal 2d (second terminal) is called a side surface 44 (fourth side surface).

[0027] In the coil component 1, the coil L1 and the coil L2 are formed from a metal plate and are fixed by the molded resin of the housing 4 at a position where the coil portion 2a of the coil L1 and the coil portion 3a of the coil L2 overlap. Furthermore, in the coil component, the terminals 2b, 2d, 3b, and 3d extending from the side of the housing 4 are bent along the side of the housing 4. However, the coil component 1 is not limited to this configuration and may be configured by stacking multiple substrates (ceramic green sheets) on which a coil wiring pattern is formed, a wound coil in which a metal wire is wound around a bobbin, or other configurations. Note that, in the coil component 1, as shown in FIG. 3 , the terminal 2d extending from the other end of the coil L1 and the terminal 3d extending from the other end of the coil L2 are separate terminals. However, the coil component 1 is not limited to this configuration and may be configured such that the other end of the coil L1 and the other end of the coil L2 are connected inside the coil component 1, with an intermediate terminal extending from the connected portion to the outside. In the case of a coil component 1 provided with intermediate wiring, in order to dissipate heat from the coil component 1, the heat dissipation properties of the intermediate wiring connected to the intermediate terminal can be improved, thereby enabling the heat from the coil component 1 to be dissipated efficiently.

[0028] In this way, when a filter circuit 100 including a coil component 1 is provided between a power supply 20 and a power supply IC 30, the coil component 1 itself generates heat due to the current flowing through the power supply line. The coil component 1 is a passive, small electronic component. Therefore, the coil component 1 has a smaller surface area than large electronic components such as active components, and a larger proportion of heat is released into the wiring via electrodes 2c, 2e, 3c, and 3e than directly from the coil component 1 itself. In particular, the power supply wiring 51 and 52 are wirings for carrying large currents, and therefore have a wide wiring width as shown in FIG. 1, allowing heat generated in the coil component 1 to be released via electrodes 2c and 3c.

[0029] However, as shown in Fig. 3, coil component 1 is a transformer coil having three terminals: a terminal of coil L1, a terminal of coil L2, and an intermediate terminal T connecting coils L1 and L2. Therefore, electrode 2c, which is a terminal of coil L1, is connected to power supply wiring 51, and electrode 3c, which is a terminal of coil L2, is connected to power supply wiring 52, so that heat can be released directly, but intermediate terminal T is not directly connected to power supply wiring 51, 52 and is far away, so that heat cannot be released efficiently.

[0030] Therefore, in the circuit board 10, the intermediate wiring 60 connected to the intermediate terminal T is extended to the vicinity of the power supply wirings 51 and 52, which have good heat dissipation properties, so that heat can be dissipated from the intermediate terminal T to the power supply wirings 51 and 52, and the heat from the coil component 1 mounted on the circuit board 10 can be efficiently dissipated to the power supply wirings 51 and 52.

[0031] 1 , the intermediate wire 60 has a portion (second portion 62) extending in a width direction perpendicular to the wiring direction of the power supply wires 51 and 52 (the extension direction of the intermediate wire 60), and the second portion 62 is disposed between the power supply wires 51 and 52. Furthermore, the intermediate wire 60 has a portion (third portion 63) extending along the wiring direction of the power supply wire 51 and a portion (fourth portion 64) extending along the wiring direction of the power supply wire 52, and the lengths of the third portion 63 and the fourth portion 64 of the intermediate wire 60 in the extension direction of the intermediate wire 60 are longer than the length of the coil component 1. By having at least one of the second portion 62 to the fourth portion 64, the intermediate wire 60 can increase the number of paths for dissipating heat from the intermediate terminal T to the power supply wires 51 and 52, and can efficiently dissipate heat from the coil component 1 mounted on the circuit board 10 to the power supply wires 51 and 52.

[0032] The power supply wiring 52 is narrower at the portion where it connects to the power supply IC 30, but has a width similar to that of the power supply wiring 51 at the portion where it connects to the coil component 1. The width of the power supply wirings 51, 52 at the portion where it connects to the coil component 1 is about five to six times thicker than the width of the portion where it connects to the power supply IC 30. The path by which each portion of the intermediate wiring 60 releases heat from the power supply wirings 51, 52 will be described in detail below. Figure 4 is a diagram for explaining the flow of heat in the coil component 1 according to the first embodiment.

[0033] 4 shows a cross section taken along plane IV-IV in FIG. 1, and illustrates a heat dissipation path from the second portion 62 of the intermediate wiring 60 to the power supply wiring 51. Note that a heat dissipation path from the second portion 62 to the power supply wiring 52 also exists but is not shown. First, in the direct heat dissipation path R1 from the second portion 62 to the power supply wiring 51, air with low thermal conductivity (approximately 0.0157 W / mK) exists between the second portion 62 and the power supply wiring 51.

[0034] Next, heat dissipation path R2, which runs from the second portion 62 to the power wiring 51 via the circuit board 10, includes the circuit board 10, which has a higher thermal conductivity than air. If the circuit board 10 is made of, for example, FR-4 (Flame Retardant Type 4), the thermal conductivity is approximately 0.3 W / mK. Furthermore, heat dissipation path R3, which runs from the second portion 62 to the power wiring 51 via the coil component 1, also includes the coil component 1, which has a higher thermal conductivity than air. If the housing 4 of the coil component 1 is made of, for example, epoxy resin, the thermal conductivity is approximately 0.2 W / mK, if it is liquid crystal polymer, the thermal conductivity is approximately 3 W / mK, and if it is ceramic, the thermal conductivity is approximately 20 to 30 W / mK. Note that, while heat dissipation path R3 preferably has contact between the main surface 40B of the coil component 1 and the second portion 62, heat dissipation may be higher than heat dissipation path R2 even if there is a small gap between the main surface 40B of the coil component 1 and the second portion 62.

[0035] That is, the heat dissipation efficiency from the second portion 62 to the power supply wiring 51 is highest along heat dissipation path R3, followed by heat dissipation path R2 and finally heat dissipation path R1. Therefore, the second portion 62 has all of the heat dissipation paths R1 to R3 because it passes under the coil component 1 and is disposed between the power supply wiring 51 and the power supply wiring 52. On the other hand, the third portion 63 and the fourth portion 64 have no portions that pass under the coil component 1, and therefore have the heat dissipation paths R1 to R2, and therefore have a lower heat dissipation ability than the second portion 62.

[0036] Next, the circuit board 10 before mounting the coil component 1, capacitor C1, etc. will be described. Figure 5 is a schematic diagram of the circuit board 10 according to the first embodiment. The circuit board 10 is, for example, FR-4, which is made by impregnating glass fiber cloth with epoxy resin and subjecting it to a heat curing treatment to form a plate. Wiring patterns such as power supply wiring 51, power supply wiring 52, GND wiring 53, and intermediate wiring 60 are provided on the surface of the circuit board 10.

[0037] The power supply wiring 51 is provided with a land electrode 81 for electrical connection with the electrode 2c of the coil component 1. The power supply wiring 52 is provided with a land electrode 82 for electrical connection with the electrode 3c of the coil component 1. The intermediate wiring 60 is provided with a land electrode 83 between the first portion 61 and the third portion 63 for electrical connection with the electrode 2e of the coil component 1. Furthermore, the intermediate wiring 60 is provided with a land electrode 84 between the first portion 61 and the fourth portion 64 for electrical connection with the electrode 3e of the coil component 1. The intermediate wiring 60 also includes a wiring 60a provided with a land electrode 85 for electrical connection with one electrode of the capacitor C1, and a wiring 60b provided with a land electrode 86 for electrical connection with the other electrode of the capacitor C1. The wiring 60a has the first portion 61 to the fourth portion 64, and the wiring 60b is electrically connected to the GND wiring 53. The wiring 60b and the GND wiring 53 are not necessarily located on the board, and a structure in which the land electrode 86 is connected to the GND wiring 53 formed inside the circuit board 10 by a via may also be used.

[0038] 5 , by providing the second portion 62 to the fourth portion 64 in the intermediate wiring 60, when the power supply 20, the power supply IC 30, the coil component 1, and the capacitor C1 are mounted, the circuit board 10 can efficiently release heat from the mounted coil component 1 to the power supply wirings 51, 52. The length of the portion of the second portion 62 of the intermediate wiring 60 that extends in the width direction of the power supply wirings 51, 52 is the same as the length of the power supply wirings 51, 52 in the width direction. However, the second portion 62 is not limited to this, and the second portion 62 may have a length that overlaps with the coil component 1 when viewed from the direction of the main surface 40A, or the tip of the second portion 62 may be extended further along the wiring direction of the power supply wirings 51, 52.

[0039] 1 includes a circuit board 10 in which second to fourth portions 62 to 64 are provided in an intermediate wiring 60, but a configuration in which only the second portion 62 is provided in an intermediate wiring 60 with high heat dissipation properties is also possible. Fig. 6 is a schematic diagram of a filter circuit 100A according to a modification of the first embodiment. Note that in the filter circuit 100A shown in Fig. 6, the same components as those in the filter circuit 100 shown in Fig. 1 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0040] As shown in FIG. 6 , a circuit board 10A is mounted with a power supply 20, a power supply IC 30 serving as a power supply circuit, and a filter circuit 100A disposed between the power supply 20 and the power supply IC 30. The filter circuit 100A includes a coil component 1, a capacitor C1 serving as a capacitance element, and an intermediate wiring 60 electrically connecting the coil component 1 and the capacitor C1. The intermediate wiring 60 has a second portion 62 to improve the heat dissipation of the coil component 1. As described in FIG. 4 , the second portion 62 has heat dissipation paths R1 to R3. Therefore, even in a circuit board 10A in which only the second portion 62 is provided in the intermediate wiring 60, the filter circuit 100A can efficiently dissipate heat from the mounted coil component 1 to the power supply wirings 51 and 52. Although the circuit board is made of FR-4, it can also be made of LTCC, which has a higher thermal conductivity than FR-4. In this case, the heat dissipation of the heat dissipation path R2 is further improved.

[0041] <Embodiment 2> In the first embodiment, one capacitor C1 is provided between the coil component 1 and the GND wiring 53, but two or more capacitors C1 may be provided in series for redundancy. When two capacitors C1 are provided between the coil component 1 and the GND wiring 53, the heat dissipation from the coil component 1 to the GND wiring 53 decreases compared to when one capacitor C1 is provided. Therefore, in the second embodiment, a configuration will be described that can more efficiently dissipate heat from the coil component to the power supply wiring.

[0042] FIG. 7 is a schematic diagram of a filter circuit 100B according to a second embodiment. In the filter circuit 100B shown in FIG. 7, the same components as those in the filter circuit 100 shown in FIG. 1 are denoted by the same reference numerals and will not be described in detail again. As shown in FIG. 7, a power supply 20, a power supply IC 30 serving as a power supply circuit, and a filter circuit 100B disposed between the power supply 20 and the power supply IC 30 are mounted on a circuit board 10B. The filter circuit 100B includes a coil component 1, capacitors C1 and C2 serving as capacitance elements, and intermediate wiring 60 electrically connecting the coil component 1 to the capacitors C1 and C2. The intermediate wiring 60 has a third portion 63 and a fourth portion 64 for improving the heat dissipation of the coil component 1. The third portion 63 is further connected to the power supply wiring 51 via a ceramic capacitor C3.

[0043] The ceramic capacitor C3 has multiple electrodes stacked close to each other within the housing. It uses a ceramic with a higher thermal conductivity than the circuit board 10B, making it easy to conduct heat. Furthermore, because no current flows through the ceramic capacitor C3, it does not short-circuit the power supply wiring 51 and the intermediate wiring 60. Furthermore, because there is no voltage difference between the power supply wiring 51 and the intermediate wiring 60, no voltage is applied to the ceramic capacitor C3. Therefore, the ceramic capacitor C3 may have a small capacitance, be compact, and inexpensive, as long as it functions as the heat dissipation path R4 from the intermediate wiring 60 to the power supply wiring 51. Conversely, if the ceramic capacitor C3 has a large capacitance, low-frequency resonance may occur between the ceramic capacitor C3 and the coil component 1, which is a transformer coil, potentially adversely affecting the noise-removing filter circuit 100B. Preferably, the ceramic capacitor C3 has a large number of electrodes to improve thermal conductivity, and is preferably made of a low-dielectric-constant material.

[0044] In the filter circuit 100B, the ceramic capacitor C3 is provided between the power supply wiring 51 and the third portion 63 to add a heat dissipation path R4, and therefore the heat from the coil component 1 can be dissipated to the power supply wirings 51 and 52 more efficiently than in a configuration in which the intermediate wiring 60 is provided with only the third portion 63 and the fourth portion 64. The ceramic capacitor C3 may be provided not only between the power supply wiring 51 and the third portion 63, but also between the power supply wiring 52 and the fourth portion 64. Of course, the ceramic capacitor C3 may be provided only between the power supply wiring 52 and the fourth portion 64, without being provided between the power supply wiring 51 and the third portion 63.

[0045] Although the intermediate wiring 60 shown in FIG. 7 does not include the second portion 62, a ceramic capacitor may be provided between the second portion 62 and the power supply wiring 52. FIG. 8 is a schematic diagram of a filter circuit 100C according to a modification of the second embodiment. In the filter circuit 100C shown in FIG. 8, the same components as those in the filter circuit 100 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will not be repeated. As shown in FIG. 8, a power supply 20, a power supply IC 30 serving as a power supply circuit, and a filter circuit 100C disposed between the power supply 20 and the power supply IC 30 are mounted on a circuit board 10C. The filter circuit 100C includes a coil component 1, capacitors C1 and C2 serving as capacitance elements, and an intermediate wiring 60 electrically connecting the coil component 1 to the capacitors C1 and C2. The intermediate wiring 60 has second to fourth portions 62 to 64 to improve the heat dissipation of the coil component 1. The third portion 63 is further connected to the power supply wiring 51 via a ceramic capacitor C3, and the second portion 62 is further connected to the power supply wiring 52 via a ceramic capacitor C4.

[0046] Like the ceramic capacitor C3, the ceramic capacitor C4 has multiple electrodes stacked close to each other within the housing. It uses a ceramic with a higher thermal conductivity than the circuit board 10C, making it easy to conduct heat. Furthermore, because no current flows through the ceramic capacitor C4, it does not short-circuit the power wiring 52 and the intermediate wiring 60. Furthermore, because there is no voltage difference between the power wiring 52 and the intermediate wiring 60, no voltage is applied to the ceramic capacitor C4. Therefore, the ceramic capacitor C4 only needs to function as the heat dissipation path R5 from the intermediate wiring 60 to the power wiring 52, and it can be small in capacitance, compact, and inexpensive. Conversely, if the ceramic capacitor C4 has a large capacitance, low-frequency resonance may occur between the transformer coil and the coil component 1, which may adversely affect the noise-removing filter circuit 100C. Preferably, the ceramic capacitor C4 has a large number of electrodes to improve thermal conductivity, and is preferably made of a low-dielectric-constant material.

[0047] The filter circuit 100C adds a heat dissipation path R4 by providing a ceramic capacitor C3 between the power supply wiring 51 and the third portion 63, and adds a heat dissipation path R5 by providing a ceramic capacitor C4 between the power supply wiring 52 and the second portion 62. This allows the filter circuit 100C to more efficiently dissipate heat from the coil component 1 to the power supply wirings 51 and 52 than the filter circuit 100B. The ceramic capacitor C4 may be provided not only between the power supply wiring 52 and the second portion 62, but also between the power supply wiring 51 and the second portion 62. Of course, the ceramic capacitor C4 may also be provided only between the power supply wiring 51 and the second portion 62, without being provided between the power supply wiring 52 and the second portion 62.

[0048] In the filter circuit 100B shown in FIG. 7 and the filter circuit 100C shown in FIG. 8, a single ceramic capacitor C3, C4 is provided between the power supply wiring 51, 52 and the intermediate wiring 60. However, this is not a limitation and multiple ceramic capacitors may be provided. Furthermore, in the filter circuit 100B shown in FIG. 7 and the filter circuit 100C shown in FIG. 8, ceramic capacitors C3, C4 are used as connecting members between the power supply wiring 51, 52 and the intermediate wiring 60. However, the connecting members are not limited to ceramic capacitors as long as they are thermally conductive and insulating. For example, a liquid crystal polymer may be provided instead of the ceramic capacitors C3, C4. While the thermal conductivity of a liquid crystal polymer is lower than that of ceramic (approximately several W / mK), it is higher than that of the circuit boards 10B, 10C (e.g., FR-4), thereby improving the heat dissipation of the filter circuit.

[0049] <Embodiment 3> In the first embodiment, an example was described in which the coil L1 and the coil L2 were configured as a single element in the coil component 1. However, the coil L1 and the coil L2 may be configured as separate elements rather than as a single element. FIG. 9 is a schematic diagram of a filter circuit 100D according to the third embodiment. Note that in the filter circuit 100D shown in FIG. 9, the same components as those in the filter circuit 100 shown in FIG. 1 are denoted by the same reference numerals and detailed description thereof will not be repeated. As shown in FIG. 9, two wound coils 1a and 1b are arranged parallel to each other along the extension direction of the second portion 62 on the circuit board 10. The wound coil 1a is configured as a first coil component, and the wound coil 1b is configured as a second coil component, each of which is a separate element.

[0050] The winding coils 1a and 1b have their winding axes parallel to the circuit board 10 and in the extension direction of the second portion 62. The winding coil 1a corresponds to L1 in FIG. 2 , with one end 2ca connected to the power supply wiring 51 and the other end 2ea connected to the intermediate wiring 60. The winding coil 1b corresponds to L2 in FIG. 2 , with one end 3ca connected to the power supply wiring 52 and the other end 3ea connected to the intermediate wiring 60. When a current flows through the winding coils 1a and 1b arranged in this manner, a magnetic field passes parallel to the circuit board 10 as shown by the arrows in FIG. 9 , and the winding coil 1a (coil L1) and the winding coil 1b (coil L2) are magnetically coupled. Therefore, even if the filter circuit 100D is configured inexpensively using general-purpose components such as the winding coils 1a and 1b, the equivalent series inductance ESL(La) can be canceled using the negative inductance generated by the magnetic coupling between the two coils, just like the filter circuit 100.

[0051] 9, the winding axes of the winding coils 1a and 1b are parallel to the circuit board 10 and in the extension direction of the second portion 62. However, the winding axes of the winding coils 1a and 1b are not limited to this and may be perpendicular to the circuit board 10. If the winding axes of the winding coils 1a and 1b are both perpendicular to the circuit board 10, a magnetic field passes in the direction perpendicular to the circuit board 10, and the winding coil 1a (coil L1) and the winding coil 1b (coil L2) are magnetically coupled. In other words, it is sufficient that the winding coils 1a and 1b are arranged in a direction that allows for magnetic coupling.

[0052] <Aspects> (1) A circuit device according to the present disclosure comprises: a circuit board on which a plurality of wirings are arranged; a coil component electrically connected to the plurality of wirings; and a capacitor element electrically connected to the coil component, wherein the coil component includes a first coil and a second coil, one end of the first coil being a first terminal, one end of the second coil being a second terminal, and a portion connecting the other end of the first coil to the other end of the second coil being an intermediate terminal, wherein the circuit board includes: a first wiring electrically connected to the first terminal, a second wiring electrically connected to the second terminal, and an intermediate wiring electrically connecting the intermediate terminal to one end of the capacitor element, wherein the intermediate wiring has a portion extending along the wiring direction of at least one of the first wiring and the second wiring, and the length of the intermediate wiring in the extension direction of the intermediate wiring is longer than the length of the coil component.

[0053] (2) In the circuit device described in (1), the width of the intermediate wiring perpendicular to the extending direction of the intermediate wiring is smaller than the widths of the first wiring and the second wiring.

[0054] (3) In the circuit device according to (1) or (2), the intermediate wiring has a portion extending in a width direction perpendicular to the extending direction of the intermediate wiring, and the portion is disposed between the first wiring and the second wiring.

[0055] (4) In the circuit device described in (3), the length of the intermediate wiring extending in the width direction is the same as the width of the first wiring and the second wiring.

[0056] (5) Another circuit device according to the present disclosure includes a circuit board on which a plurality of wirings are arranged, a coil component electrically connected to the plurality of wirings, and a capacitor element electrically connected to the coil component, wherein the coil component includes a first coil and a second coil, one end of the first coil being a first terminal, one end of the second coil being a second terminal, and a portion connecting the other end of the first coil to the other end of the second coil being an intermediate terminal, and the circuit board includes a first wiring electrically connected to the first terminal, a second wiring electrically connected to the second terminal, and an intermediate wiring electrically connecting the intermediate terminal to one end of the capacitor element, wherein the intermediate wiring has a portion extending in a width direction perpendicular to the wiring direction of the first wiring and the second wiring, and the portion is disposed between the first wiring and the second wiring.

[0057] (6) In the circuit device according to (5), the length of the intermediate wiring extending in the width direction is the same as the width of the first wiring and the second wiring.

[0058] (7) In the circuit device described in (5) or (6), the intermediate wiring has a portion extending along the wiring direction of at least one of the first wiring and the second wiring, and the length of the intermediate wiring in the extension direction of the intermediate wiring is longer than the length of the coil component.

[0059] (8) In the circuit device described in any one of (1) to (7), the intermediate terminal includes a first intermediate terminal and a second intermediate terminal, the first intermediate terminal is electrically connected to the other end of the first coil, and the second intermediate terminal is electrically connected to the other end of the second coil.

[0060] (9) In the circuit device described in any one of (1) to (7), the coil components include a first coil component having a first coil and a second coil component having a second coil, and the first coil component and the second coil component are arranged in a direction in which they are magnetically coupled.

[0061] (10) In the circuit device described in any one of (1) to (9), the intermediate wiring is connected to at least one of the first wiring and the second wiring by a connecting member having thermal conductivity and insulating properties.

[0062] (11) In the circuit device according to (10), the connection member is a ceramic capacitor.

[0063] (12) In the circuit device according to any one of (1) to (11), the coil component has a first coil and a second coil that are magnetically coupled to each other.

[0064] (13) A circuit board according to the present disclosure is a circuit board capable of mounting a coil component having a plurality of wirings arranged thereon and electrically connected to the plurality of wirings, and a capacitor element electrically connected to the coil component, the circuit board including: a first wiring electrically connected to a first terminal of a first coil included in the coil component; a second wiring electrically connected to a second terminal of a second coil included in the coil component; and an intermediate wiring electrically connecting an intermediate terminal connecting the first coil and the second coil to one end of the capacitor element, the intermediate wiring having a portion extending along the wiring direction of at least one of the first wiring and the second wiring, and the length of the intermediate wiring in the extension direction of the intermediate wiring being longer than the length of the coil component.

[0065] (14) Another circuit board according to the present disclosure is a circuit board capable of mounting a coil component having a plurality of wirings arranged thereon and electrically connecting with the plurality of wirings, and a capacitor element electrically connecting with the coil component, the circuit board including: a first wiring electrically connecting with a first terminal of a first coil included in the coil component; a second wiring electrically connecting with a second terminal of a second coil included in the coil component; and an intermediate wiring electrically connecting an intermediate terminal connecting the first coil and the second coil with one end of the capacitor element, the intermediate wiring having a portion extending in a width direction perpendicular to the wiring direction of the first wiring and the second wiring, the portion being arranged between the first wiring and the second wiring.

[0066] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0067] 1 coil component, 2a, 3a coil portion, 2b, 2d, 3b, 3d terminal, 2c, 2e, 3c, 3e electrode, 4 housing, 10, 10A to 10C circuit board, 20 power supply, 30 power supply IC, 51, 52 power supply wiring, 60 intermediate wiring, 81 to 86 land electrode, 100, 100A to 100C filter circuit, C1, C2 capacitor.

Claims

1. A circuit board on which a plurality of wirings are arranged, a coil component electrically connected to the plurality of wirings, and a capacitor element electrically connected to the coil component, wherein the coil component includes a first coil and a second coil, one end of the first coil is a first terminal, one end of the second coil is a second terminal, and a connection portion between the other end of the first coil and the other end of the second coil is an intermediate terminal, wherein the circuit board includes a first wiring electrically connected to the first terminal, a second wiring electrically connected to the second terminal, and an intermediate wiring electrically connecting the intermediate terminal and one end of the capacitor element, wherein the intermediate wiring has a portion extending along at least one of the wiring directions of the first wiring and the second wiring, and a length of the intermediate wiring in the extending direction of the intermediate wiring is longer than a length of the coil component, a circuit device.

2. The circuit device according to claim 1, wherein a thickness of a width of the intermediate wiring orthogonal to the extending direction of the intermediate wiring is thinner than widths of the first wiring and the second wiring.

3. The circuit device according to claim 1, wherein the intermediate wiring has a portion extending in a width direction orthogonal to the extending direction of the intermediate wiring, and the portion is disposed between the first wiring and the second wiring.

4. The circuit device according to claim 3, wherein a length of the portion of the intermediate wiring extending in the width direction is the same as lengths of widths of the first wiring and the second wiring.

5. A circuit board on which a plurality of wirings are arranged, a coil component electrically connected to the plurality of wirings, and a capacitor element electrically connected to the coil component, wherein the coil component includes a first coil and a second coil, one end of the first coil is a first terminal, one end of the second coil is a second terminal, and a connection portion between the other end of the first coil and the other end of the second coil is an intermediate terminal, wherein the circuit board includes a first wiring electrically connected to the first terminal, a second wiring electrically connected to the second terminal, and an intermediate wiring electrically connecting the intermediate terminal and one end of the capacitor element, wherein the intermediate wiring has a portion extending in a width direction orthogonal to the wiring directions of the first wiring and the second wiring, and the portion is disposed between the first wiring and the second wiring, a circuit device.

6. The circuit device according to claim 5, wherein the intermediate wiring has a length of a portion extending in the width direction that is the same as the lengths of the widths of the first wiring and the second wiring.

7. The circuit device according to claim 6, wherein the intermediate wiring has a portion extending along at least one of the wiring directions of the first wiring and the second wiring, and a length of the intermediate wiring in the extending direction of the intermediate wiring is longer than a length of the coil component.

8. The intermediate terminal includes a first intermediate terminal and a second intermediate terminal. The circuit device according to any one of claims 1 to 7, wherein the first intermediate terminal is electrically connected to the other end of the first coil, and the second intermediate terminal is electrically connected to the other end of the second coil.

9. The circuit device according to any one of claims 1 to 7, wherein the coil component includes a first coil component having the first coil and a second coil component having the second coil, and the first coil component and the second coil component are arranged in a magnetically coupled direction.

10. The circuit device according to any one of claims 1 to 7, wherein the intermediate wiring is a connecting member having thermal conductivity and insulation, and is connected to at least one of the first wiring and the second wiring.

11. The circuit device according to claim 10, wherein the connecting member is a ceramic capacitor.

12. The circuit device according to any one of claims 1 to 7, wherein the coil component has the first coil and the second coil magnetically coupled.

13. A circuit board on which a plurality of wirings are arranged, and a coil component electrically connected to the plurality of wirings and a capacitor element electrically connected to the coil component can be mounted, a first wiring electrically connected to a first terminal of a first coil included in the coil component, a second wiring electrically connected to a second terminal of a second coil included in the coil component, and an intermediate wiring electrically connecting an intermediate terminal connecting the first coil and the second coil and one end of the capacitor element, wherein the intermediate wiring has a portion extending along at least one of the wiring directions of the first wiring and the second wiring, and a length of the intermediate wiring in the extending direction of the intermediate wiring is longer than a length of the coil component.

14. A circuit board on which a plurality of wirings are arranged, and a coil component electrically connected to the plurality of wirings and a capacitor element electrically connected to the coil component can be mounted, A first wiring electrically connected to a first terminal of a first coil included in the coil component; A second wiring electrically connected to a second terminal of a second coil included in the coil component; An intermediate wiring electrically connecting an intermediate terminal connecting the first coil and the second coil and one end of the capacitor element; and The intermediate wiring has a portion extending in a width direction orthogonal to a wiring direction of the first wiring and the second wiring, and the portion is disposed between the first wiring and the second wiring, a circuit board.