Circuit devices and circuit boards

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

Technical Field

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

Background Art

[0002] In electronic devices, noise countermeasures using a filter circuit are often performed. Examples of the filter circuit used for noise countermeasures include an EMI (Electro-Magnetic Interference) removal filter, which removes unnecessary components while passing necessary components of the current flowing through a conductor. Further, since the filter circuit uses a capacitor which is a capacitance element, it is known that the noise suppression effect is reduced by the equivalent series inductance (ESL: Equivalent Series Inductance) which is the parasitic inductance of the capacitor.

[0003] There is known a technique for canceling the equivalent series inductance ESL of a capacitor with a negative inductance generated by magnetically coupling two coils, and broadening the noise suppression effect of a filter circuit (for example, Japanese Patent Application Laid-Open No. 2001-160728: Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When a coil component described in Japanese Patent Publication No. 2001-160728 (Patent Document 1) is used in a filter circuit, it is connected in series with the power line, causing the coil component itself to generate heat due to the current flowing through 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 constraints on component size. In particular, in circuit devices that mount coil components, such as filter circuits, a configuration that can efficiently dissipate heat from the coil component is desired.

[0006] Therefore, the object of this disclosure is to provide a circuit device and a circuit board that can dissipate heat from coil components. [Means for solving the problem]

[0007] A circuit device according to one embodiment of the present disclosure comprises a circuit board on which a plurality of wires are arranged, a coil component electrically connected to the plurality of wires, 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 designated as a first terminal, one end of the second coil designated as a second terminal, and the portion connecting the other end of the first coil and the other end of the second coil designated as an intermediate terminal. The circuit board includes a first wire electrically connected to the first terminal, a second wire electrically connected to the second terminal, and an intermediate wire electrically connected to the intermediate terminal and one end of the capacitor element. The intermediate wire is, Apart from the part that electrically connects the intermediate terminal and one end of the capacitor element, Along the wiring direction of at least one of the first and second wirings , in the vicinity of at least one of the first and second wirings Having an extended portion, When viewing the surface of a circuit board with coil components mounted in a plan view, the portion extending in the wiring direction. The length The length of one side of the coil component is long.

[0008] Another circuit device according to one embodiment of the present disclosure comprises a circuit board on which a plurality of wires are arranged, a coil component electrically connected to the plurality of wires, 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 designated as a first terminal, one end of the second coil as a second terminal, and the portion connecting the other end of the first coil and the other end of the second coil as an intermediate terminal. The circuit board includes a first wire electrically connected to the first terminal, a second wire electrically connected to the second terminal, and an intermediate wire electrically connected to the intermediate terminal and one end of the capacitor element. The intermediate wire is, Apart from the part that electrically connects the intermediate terminal and one end of the capacitor element, It has a portion that extends in a width direction perpendicular to the wiring direction of the first and second wirings, and the portion is positioned between the first and second wirings. When viewing the surface of a circuit board on which a coil component is mounted in plan view, the length of the portion that extends in the width direction without being connected to other circuits is longer than the length of one side of the coil component. .

[0009] A circuit board according to one embodiment of the present disclosure is a circuit board on which a plurality of wires are arranged and on which a coil component electrically connected to the plurality of wires and a capacitor element electrically connected to the coil component can be mounted. The circuit board includes a first wire electrically connected to the first terminal of a first coil included in the coil component, a second wire electrically connected to the second terminal of a second coil included in the coil component, and an intermediate wire electrically connected to an intermediate terminal connecting the first coil and the second coil and one end of the capacitor element. The intermediate wire is, Apart from the part that electrically connects the intermediate terminal and one end of the capacitor element, Along the wiring direction of at least one of the first and second wirings , in the vicinity of at least one of the first and second wirings Having an extended portion, When viewing the surface of a circuit board with coil components mounted in a plan view, the portion extending in the wiring direction. The length The length of one side of the coil component is long.

[0010] Another circuit board according to one embodiment of the present disclosure is a circuit board on which a plurality of wires are arranged and on which a coil component electrically connected to the plurality of wires and a capacitor element electrically connected to the coil component can be mounted. The circuit board includes a first wire electrically connected to the first terminal of a first coil included in the coil component, a second wire electrically connected to the second terminal of a second coil included in the coil component, and an intermediate wire electrically connected to an intermediate terminal connecting the first coil and the second coil and one end of the capacitor element. The intermediate wire is, Apart from the part that electrically connects the intermediate terminal and one end of the capacitor element,It has a portion extending in the width direction orthogonal to the wiring directions of the first wiring and the second wiring, and this portion is disposed between the first wiring and the second wiring. When viewing the surface of a circuit board on which a coil component is mounted in plan view, the length of the portion that extends in the width direction without being connected to other circuits is longer than the length of one side of the coil component. .

Effect of the Invention

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

Brief Description of the Drawings

[0012] [Figure 1] It is a schematic diagram of the filter circuit according to Embodiment 1. [Figure 2] It is a circuit diagram of the filter circuit according to Embodiment 1. [Figure 3] It is a perspective view of the coil component mounted on the filter circuit according to Embodiment 1. [Figure 4] It is a diagram for explaining the flow of heat in the coil component according to Embodiment 1. [Figure 5] [[ID=2⑨]]It is a schematic diagram of the circuit board according to Embodiment 1. [Figure 6] It is a schematic diagram of the filter circuit according to a modification of Embodiment 1. [Figure 7] It is a schematic diagram of the filter circuit according to Embodiment 2. [Figure 8] It is a schematic diagram of the filter circuit according to a modification of Embodiment 2. [Figure 9] It is a schematic diagram of the filter circuit according to Embodiment 3.

Modes for Carrying Out the Invention

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

[0014] <Embodiment 1> First, the filter circuit according to Embodiment 1 and the coil component mounted on the filter circuit will be described while referring to the drawings. FIG. 1 is a schematic diagram of a filter circuit 100 according to Embodiment 1. FIG. 2 is a circuit diagram of the filter circuit 100 according to Embodiment 1. FIG. 3 is a perspective view of a coil component 1 mounted on the filter circuit 100 according to Embodiment 1. Regarding 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-back 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 on a filter circuit 100 used for noise countermeasures of a power supply wiring. As will be described later, in order to cancel the parasitic inductance of the capacitor mounted on the filter circuit 100, the coil component 1 magnetically couples two coils (coil L1 and coil L2).

[0016] On the circuit board 10, as shown in FIG. 1, a power supply 20, a power supply IC 30 which is a power supply circuit, and a filter circuit 100 arranged between the power supply 20 and the power supply IC 30 are mounted. The circuit board 10 shown in FIG. 1 is an example, and the power supply 20 may be a battery, a connection terminal connected to an external power supply, or a power supply circuit that performs boosting or bucking. Also, the power supply IC 30 may be a power supply circuit that performs boosting or bucking, or a power supply circuit such as a converter. Furthermore, instead of the power supply IC 30, it may be a circuit driven by the power from the power supply 20. The filter circuit 100 may be arranged at any location on the circuit board 10 as long as it is arranged to remove unnecessary components between the input and the output.

[0017] The filter circuit 100 includes a coil component 1, a capacitor C1 which is a capacitance element, and an intermediate wiring 60 which electrically connects the coil component 1 and the capacitor C1. The electrode 2c (first terminal) of the coil component 1 is electrically connected to the power supply 20 via the power supply wiring 51 (first wiring). On the other hand, the electrode 3c (second terminal) of the coil component 1 is electrically connected to the power supply IC 30 via the power supply wiring 52 (second wiring). The electrodes 2e and 3e of the coil component 1 are the intermediate terminals T of the two coils and are electrically connected by the first part 61 of the intermediate wiring 60. The intermediate terminals T are connected to the GND wiring 53 via the capacitor C1 through the intermediate wiring 60. Electrode 2e may be considered the first intermediate terminal and electrode 3e the second intermediate terminal. The intermediate wiring 60 has second parts 62 to fourth parts 64 to improve the heat dissipation of the coil component 1, as will be described later. To be electrically connected refers to a state in which electrical conductivity is maintained through wiring, soldering, wires, etc. This includes both direct connections between wiring and coil components, as well as cases where conductive materials are placed in between.

[0018] The filter circuit 100 is an EMI removal filter, as shown in Figure 2, for example, and is a third-order T-type LC filter circuit. This filter circuit 100 connects electrode 2c to the power supply 20 and electrode 3c to the power supply IC 30. The filter circuit 100 allows the necessary components of the current flowing from the power supply 20 to the power supply IC 30 to pass through while removing unwanted components. Since this filter circuit 100 uses a capacitor C1, which is a capacitance element, the negative inductance generated by the magnetic coupling of the two coils is used to cancel the equivalent series inductance ESL(La) of the capacitor.

[0019] In the following embodiment, a third-order T-type LC filter circuit is used as the configuration for the filter circuit 100, but similar coil components can 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] As shown in Figure 2, capacitor C1 has one end connected to the intermediate terminal T and the other end connected to the GND wiring 53. Note that capacitor C1 may be a multilayer ceramic capacitor mainly composed of BaTiO3 (barium titanate), a multilayer ceramic capacitor mainly composed of other materials, or a capacitor of another type that is not a multilayer ceramic capacitor, such as an aluminum electrolytic capacitor. 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. Furthermore, 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 connected to the intermediate terminal T. Coils L1 and L2 are magnetically coupled in an additive connection, generating a negative inductance component relative to 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, the filter circuit 100, composed of capacitor C1, coil L1, and coil L2, can suppress the reduction in noise suppression effect in the high-frequency band caused by the parasitic inductance of capacitor C by canceling out the parasitic inductance of capacitor C1 with the negative inductance component due to the mutual inductance of coil L1 and coil L2, thereby improving the noise suppression effect in the high-frequency band.

[0022] Specifically, as shown in Figure 3, coil component 1 includes coil L1 (first coil), coil L2 (second coil), and housing 4. Coils L1 and L2 are formed from metal plates, for example, copper or an alloy of copper and other metals. Coils L1 and L2, formed from metal plates, are covered with an insulating material (not shown). Specifically, the insulating material covering coils L1 and 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 arranged inside the housing 4 parallel to the main surface 40A (first main surface). The coil portion 2a is shown as a single-turn coil, but it may be a multi-turn coil. 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 in the direction of the main surface 40B (second main surface). Terminal 2b shown in Figure 1 is provided up to the main surface 40B, and the portion in contact with the main surface 40B constitutes an electrode 2c. Similarly, terminal 2d is provided up to the main surface 40B, and the portion in contact with the main surface 40B constitutes an electrode 2e. When the coil component 1 is mounted on the circuit board 10, the electrode 2c is electrically connected to the first portion 61 of the 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 positioned parallel to the main surface 40A and above the coil portion 2a inside the housing 4. Although the coil portion 3a is shown 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 in the direction of the main surface 40B. The terminal 3b shown in Figure 1 is provided up to the main surface 40B, and the portion in contact with the main surface 40B constitutes an electrode 3c. Similarly, the terminal 3d is provided up to the main surface 40B, and the portion in contact with 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. Electrodes 2e and 3e are electrically connected by the first portion 61 of the intermediate wiring 60, which is placed on the circuit board 10. By connecting electrodes 2e and 3e with the first portion 61 of the intermediate wiring 60, coils L1 and L2 are connected in series, and electrodes 2e and 3e constitute the intermediate terminal T between coils L1 and L2.

[0025] When the terminal 2b of coil L1 is connected to the power supply 20 via electrode 2c, current flows clockwise through coil section 2a. The current flowing through coil section 2a then flows counterclockwise through terminal 2d, electrode 2e, the first part 61 of the intermediate wiring 60, electrode 3e, and terminal 3d. In coil L2, current flows clockwise from terminal 3d through coil section 3a. As a result, a magnetic field is generated in coil section 2a in the direction from the main surface 40A to the main surface 40B (-Z direction). Similarly, a magnetic field is generated in coil section 3a in the direction from the main surface 40A to the main surface 40B (-Z direction). Since coil sections 2a and 3a are arranged to overlap when viewed from the direction of the main surface 40A, coils L1 and L2 are magnetically coupled.

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

[0027] In coil component 1, coils L1 and L2 are formed from a metal plate, and the coil portion 2a of coil L1 and the coil portion 3a of coil L2 are fixed to the housing 4 with molded resin at the overlapping position. Furthermore, in this coil component, terminals 2b, 2d, 3b, and 3d that are drawn out from the side of the housing 4 are bent along the side of the housing 4. However, coil component 1 is not limited to this configuration, and may also be a configuration in which multiple substrates (ceramic green sheets) on which the wiring pattern of the coil is formed are stacked, or a wound coil in which metal wire is wound around a bobbin, or other configurations. Note that in coil component 1, as shown in Figure 3, an example is shown in which terminal 2d extending from the other end of coil L1 and terminal 3d extending from the other end of coil L2 are separate terminals. However, coil component 1 is not limited to this, and may also be a configuration in which the other end of coil L1 and the other end of coil L2 are connected inside coil component 1, and an intermediate terminal extends to the outside from the connected part. In the case of a coil component 1 with intermediate wiring, the heat from the coil component 1 can be efficiently dissipated by improving the heat dissipation performance of the intermediate wiring connected to the intermediate terminals.

[0028] Thus, when a filter circuit 100 including a coil component 1 is provided between the power supply 20 and the power supply IC 30, the coil component 1 itself will generate heat due to the current flowing through the power supply line. The coil component 1 is a passive component and a small electronic component. Therefore, the coil component 1 has a smaller surface area compared to larger electronic components such as active components, and the proportion of heat released to the wiring via electrodes 2c, 2e, 3c, and 3e is greater than the proportion of heat released directly from the coil component 1 itself. In particular, since the power supply wiring 51 and 52 are wires that carry large currents, the width of the wiring is thick as shown in Figure 1, so the heat generated by the coil component 1 can be released via electrodes 2c and 3c.

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

[0030] Therefore, in the circuit board 10, by extending the intermediate wiring 60 connected to the intermediate terminal T to the vicinity of the power supply wirings 51 and 52, which have good heat dissipation, heat can be released 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 released to the power supply wirings 51 and 52.

[0031] Specifically, as shown in Figure 1, the intermediate wiring 60 has a portion (second portion 62) that extends in a width direction perpendicular to the wiring direction of the power supply wirings 51 and 52 (the extension direction of the intermediate wiring 60), and this second portion 62 is positioned between the power supply wirings 51 and 52. Furthermore, the intermediate wiring 60 has a portion (third portion 63) that extends along the wiring direction of the power supply wiring 51, and a portion (fourth portion 64) that extends along the wiring direction of the power supply wiring 52, and the lengths of the third portion 63 and fourth portion 64 of the intermediate wiring 60 in the extension direction 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 wiring 60 can increase the number of paths for releasing heat 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 released to the power supply wirings 51 and 52.

[0032] The power supply wiring 52 is narrower where it connects to the power supply IC 30, but is about the same width as the power supply wiring 51 where it connects to the coil component 1. The width of the power supply wiring 51 and 52 where they connect to the coil component 1 is about 5 to 6 times wider than the width of the part where they connect to the power supply IC 30. The paths by which each part of the intermediate wiring 60 dissipates heat from these power supply wirings 51 and 52 will be explained in detail. Figure 4 is a diagram illustrating the heat flow in the coil component 1 according to Embodiment 1.

[0033] The cross-section shown in Figure 4 is the cross-section of the IV-IV plane in Figure 1, illustrating the heat dissipation path from the second portion 62 of the intermediate wiring 60 to the power wiring 51. A similar heat dissipation path also exists from the second portion 62 to the power wiring 52, but it is not shown in the illustration. First, in the direct heat dissipation path R1 from the second portion 62 to the power wiring 51, there is air with low thermal conductivity (approximately 0.0157 W / mK) between the second portion 62 and the power wiring 51.

[0034] Next, in the heat dissipation path R2 from the second part 62 through the circuit board 10 to the power supply wiring 51, there is a circuit board 10 with a higher thermal conductivity than air. If the circuit board 10 is, for example, FR-4 (Flame Retardant Type 4), its thermal conductivity is approximately 0.3 W / mK. Furthermore, in the heat dissipation path R3 from the second part 62 through the coil component 1 to the power supply wiring 51, there is a coil component 1 with a higher thermal conductivity than air. If the housing 4 of the coil component 1 is, for example, epoxy resin, the thermal conductivity is approximately 0.2 W / mK; if it is liquid crystal polymer, it is approximately 3 W / mK; and if it is ceramic, the thermal conductivity is approximately 20-30 W / mK. It is preferable that the main surface 40B of the coil component 1 and the second part 62 are in contact in the heat dissipation path R3, but even if there is a small gap between the main surface 40B of the coil component 1 and the second part 62, the heat dissipation may be higher than that of the heat dissipation path R2.

[0035] In other words, the heat dissipation from the second section 62 to the power supply wiring 51 can be most efficient in the order of heat dissipation path R3, heat dissipation path R2, and heat dissipation path R1. Therefore, since the second section 62 passes under the coil component 1 and is located between the power supply wiring 51 and the power supply wiring 52, it has all of the heat dissipation paths R1 to R3. On the other hand, the third section 63 and the fourth section 64 do not have any parts that pass under the coil component 1, so they have heat dissipation paths R1 to R2, and their ability to dissipate heat is lower compared to the second section 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 Embodiment 1. The circuit board 10 is, for example, FR-4, which is made by impregnating a glass fiber cloth with epoxy resin and heat-curing it 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 electrically connecting to the electrode 2c of the coil component 1. The power supply wiring 52 is provided with a land electrode 82 for electrically connecting to the electrode 3c of the coil component 1. The intermediate wiring 60 is provided with a land electrode 83 between the first section 61 and the third section 63 for electrically connecting to the electrode 2e of the coil component 1. Furthermore, the intermediate wiring 60 is provided with a land electrode 84 between the first section 61 and the fourth section 64 for electrically connecting to the electrode 3e of the coil component 1. The intermediate wiring 60 also includes wiring 60a with a land electrode 85 for electrically connecting to one electrode of the capacitor C1, and wiring 60b with a land electrode 86 for electrically connecting to the other electrode of the capacitor C1. Wiring 60a has first sections 61 to fourth sections 64, and wiring 60b is electrically connected to the GND wiring 53. The wiring 60b and GND wiring 53 are not necessarily located on the board; they may be connected via vias from the land electrode 86 to the GND wiring 53 formed on the inside of the circuit board 10.

[0038] The circuit board 10 shown in Figure 5, by providing second to fourth sections 62 to 64 on the intermediate wiring 60, allows for efficient heat dissipation from the mounted coil component 1 to the power wiring 51 and 52 when the power supply 20, power supply IC 30, coil component 1, and capacitor C1 are mounted. The length of the portion of the second section 62 of the intermediate wiring 60 that extends in the width direction of the power wiring 51 and 52 is the same as the width direction of the power wiring 51 and 52. However, the second section 62 is not limited to this, and even if its length overlaps with the coil component 1 when viewed from the direction of the main surface 40A, the tip of the second section 62 may be further extended along the wiring direction of the power wiring 51 and 52.

[0039] The filter circuit 100 shown in Figure 1 has a circuit board 10 with second parts 62 to fourth parts 64 provided on the intermediate wiring 60, but a configuration in which only the second part 62 is provided on the intermediate wiring 60, which has high heat dissipation, is also possible. Figure 6 is a schematic diagram of a modified filter circuit 100A according to Embodiment 1. In the filter circuit 100A shown in Figure 6, the same reference numerals are used for components that are the same as those in the filter circuit 100 shown in Figure 1, and detailed explanations are not repeated.

[0040] As shown in Figure 6, the circuit board 10A is equipped with a power supply 20, a power supply IC 30 which is a power supply circuit, and a filter circuit 100A positioned between the power supply 20 and the power supply IC 30. The filter circuit 100A includes a coil component 1, a capacitor C1 which is a capacitance element, and an intermediate wiring 60 which electrically connects the coil component 1 and the capacitor C1. The intermediate wiring 60 is provided with a second section 62 to improve the heat dissipation of the coil component 1. As explained in Figure 4, the second section 62 has heat dissipation paths R1 to R3, so even if the circuit board 10A is equipped only with the second section 62 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. In addition, although the circuit board is shown as an example of FR-4, it can also be formed of LTCC which has a higher thermal conductivity than FR-4, in which case the heat dissipation of the heat dissipation path R2 will be further improved.

[0041] <Embodiment 2> In Embodiment 1, one capacitor C1 was provided between the coil component 1 and the GND wiring 53. However, for redundancy, two or more capacitors C1 may be provided in series. 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 only one capacitor C1 is provided. Therefore, Embodiment 2 describes a configuration that can more efficiently dissipate heat from the coil component to the power supply wiring.

[0042] Figure 7 is a schematic diagram of the filter circuit 100B according to Embodiment 2. In the filter circuit 100B shown in Figure 7, the same reference numerals are used for components that are the same as those in the filter circuit 100 shown in Figure 1, and detailed explanations will not be repeated. As shown in Figure 7, the circuit board 10B is equipped with a power supply 20, a power supply IC 30 which is a power supply circuit, and a filter circuit 100B which is positioned between the power supply 20 and the power supply IC 30. The filter circuit 100B includes a coil component 1, capacitors C1 and C2 which are capacitance elements, and intermediate wiring 60 which electrically connects the coil component 1 and capacitors C1 and C2. The intermediate wiring 60 has a third section 63 and a fourth section 64 to improve the heat dissipation of the coil component 1. The third section 63 is further connected to the power supply wiring 51 with a ceramic capacitor C3.

[0043] The ceramic capacitor C3 has numerous electrodes stacked alternately in close proximity within its casing, and uses ceramic with a higher thermal conductivity than the circuit board 10B, making it efficient at conducting heat. Furthermore, since no current flows through the ceramic capacitor C3, it does not short-circuit the power supply wiring 51 and the intermediate wiring 60. Also, since 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, if the ceramic capacitor C3 functions as a heat dissipation path R4 from the intermediate wiring 60 to the power supply wiring 51, it can have a small capacitance and be small and inexpensive. Conversely, if the capacitance of the ceramic capacitor C3 is large, low-frequency resonance may occur between it 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 it is desirable that it be made of a low dielectric constant material.

[0044] The filter circuit 100B adds a heat dissipation path R4 by providing a ceramic capacitor C3 between the power supply wiring 51 and the third section 63. Compared to a configuration where only the third section 63 and the fourth section 64 are provided in the intermediate wiring 60, this configuration can efficiently dissipate heat from the coil component 1 to the power supply wiring 51 and 52. The ceramic capacitor C3 may be provided not only between the power supply wiring 51 and the third section 63, but also between the power supply wiring 52 and the fourth section 64. Of course, the ceramic capacitor C3 may be provided only between the power supply wiring 52 and the fourth section 64, without being provided between the power supply wiring 51 and the third section 63.

[0045] The intermediate wiring 60 shown in Figure 7 does not have a second portion 62, but a ceramic capacitor may be provided between the second portion 62 and the power supply wiring 52. Figure 8 is a schematic diagram of a modified example of the second embodiment of the filter circuit 100C. In the filter circuit 100C shown in Figure 8, the same reference numerals are used for components that are the same as those in the filter circuit 100 shown in Figure 1, and detailed explanations will not be repeated. As shown in Figure 8, the circuit board 10C is equipped with a power supply 20, a power supply IC 30 which is a power supply circuit, and a filter circuit 100C which is positioned between the power supply 20 and the power supply IC 30. The filter circuit 100C includes a coil component 1, capacitors C1 and C2 which are capacitance elements, and intermediate wiring 60 which electrically connects the coil component 1 and capacitors C1 and C2. The intermediate wiring 60 has second portions 62 to fourth portions 64 to improve the heat dissipation of the coil component 1. The third section 63 is further connected to the power supply wiring 51 with a ceramic capacitor C3, and the second section 62 is further connected to the power supply wiring 52 with a ceramic capacitor C4.

[0046] Like ceramic capacitor C3, ceramic capacitor C4 has numerous electrodes stacked alternately in close proximity within its casing, and uses ceramic with a higher thermal conductivity than the circuit board 10C, making it efficient at conducting heat. Furthermore, since no current flows through ceramic capacitor C4, it does not short-circuit the power supply wiring 52 and the intermediate wiring 60. Also, since there is no voltage difference between the power supply wiring 52 and the intermediate wiring 60, no voltage is applied to ceramic capacitor C4. Therefore, ceramic capacitor C4 only needs to function as a heat dissipation path R5 from the intermediate wiring 60 to the power supply wiring 52, and can have a small capacitance and be small and inexpensive. Conversely, if ceramic capacitor C4 has a large capacitance, low-frequency resonance may occur between it and the coil component 1, which is a transformer coil, potentially adversely affecting the noise-removing filter circuit 100C. Preferably, ceramic capacitor C4 has a large number of electrodes to improve thermal conductivity, and it is desirable that it be 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 section 63, and adds a heat dissipation path R5 by providing a ceramic capacitor C4 between the power supply wiring 52 and the second section 62. Therefore, compared to the filter circuit 100B, it can efficiently dissipate heat from the coil component 1 to the power supply wirings 51 and 52. The ceramic capacitor C4 may be provided not only between the power supply wiring 52 and the second section 62, but also between the power supply wiring 51 and the second section 62. Of course, the ceramic capacitor C4 may be provided only between the power supply wiring 51 and the second section 62, without being provided between the power supply wiring 52 and the second section 62.

[0048] In the filter circuits 100B shown in Figure 7 and 100C shown in Figure 8, a configuration in which one ceramic capacitor C3 and C4 is provided between the power supply wiring 51 and 52 and the intermediate wiring 60 has been described, but the configuration is not limited to this, and multiple ceramic capacitors may be provided. Also, in the filter circuits 100B shown in Figure 7 and 100C shown in Figure 8, an example in which ceramic capacitors C3 and C4 are used as connecting members between the power supply wiring 51 and 52 and the intermediate wiring 60 has been described, but the configuration is not limited to ceramic capacitors as long as the connecting member has thermal conductivity and insulating properties. For example, liquid crystal polymer may be provided instead of ceramic capacitors C3 and C4. The thermal conductivity of liquid crystal polymer is about a few W / mK, which is lower than that of ceramic, but it is higher than that of the circuit boards 10B and 10C (for example, FR-4), so it can improve the heat dissipation of the filter circuit.

[0049] <Embodiment 3> In Embodiment 1, an example was described in which coil L1 and coil L2 are composed of a single coil component 1. However, coil L1 and coil L2 may be composed of separate components rather than a single component. Figure 9 is a schematic diagram of a filter circuit 100D according to Embodiment 3. In the filter circuit 100D shown in Figure 9, the same reference numerals are used for components that are the same as those in the filter circuit 100 shown in Figure 1, and detailed explanations are not repeated. As shown in Figure 9, two winding coils 1a and 1b are arranged parallel to each other on the circuit board 10 along the extension direction of the second portion 62. Winding coil 1a is composed of a first coil component, and winding coil 1b is composed of a second coil component, each being a separate component.

[0050] The wound coils 1a and 1b are parallel to the circuit board 10 and have winding axes in the direction of extension of the second portion 62. Winding coil 1a corresponds to L1 in Figure 2, with one end 2ca connected to the power supply wiring 51 and the other end 2ea connected to the intermediate wiring 60. Winding coil 1b corresponds to L2 in Figure 2, with one end 3ca connected to the power supply wiring 52 and the other end 3ea connected to the intermediate wiring 60. When 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 Figure 9, and winding coil 1a (coil L1) and winding coil 1b (coil L2) become magnetically coupled. Therefore, even if the filter circuit 100D is constructed inexpensively using general-purpose components such as winding coils 1a and 1b, it can cancel the equivalent series inductance ESL(La) using the negative inductance generated by the magnetic coupling of the two coils, just like the filter circuit 100.

[0051] In the filter circuit 100D shown in Figure 9, the winding axes of the winding coils 1a and 1b are described as being parallel to the circuit board 10 and in the direction of extension 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 both winding coils 1a and 1b are perpendicular to the circuit board 10, a magnetic field will pass perpendicular to the circuit board 10, and the winding coil 1a (coil L1) and the winding coil 1b (coil L2) will be magnetically coupled. In other words, the winding coils 1a and 1b only need to be arranged in a direction that allows for magnetic coupling.

[0052] <Mode> (1) The circuit device relating to this disclosure is A circuit board on which multiple wires are arranged, Multiple wires and electrically connected coil components, It comprises a coil component and a capacitor element that is electrically connected to it, The coil components are, Including a first coil and a second coil, One end of the first coil is designated as the first terminal, one end of the second coil as the second terminal, and the connection point between the other end of the first coil and the other end of the second coil is designated as the intermediate terminal. The circuit board is A first wire that is electrically connected to the first terminal, A second wire that is electrically connected to the second terminal, An intermediate wire that electrically connects the intermediate terminal and one end of the capacitor element, including, The intermediate wiring has a portion that extends along at least one of the wiring directions of the first wiring and the second wiring, and the length of the intermediate wiring in the direction of extension is longer than the length of the coil component.

[0053] (2) The circuit device described in (1) is The width of the intermediate wiring perpendicular to the direction of extension of the intermediate wiring is narrower than the width of the first and second wirings.

[0054] (3) The circuit device described in (1) or (2) is The intermediate wiring has a portion that extends in a width direction perpendicular to the direction of extension of the intermediate wiring, and this portion is positioned between the first wiring and the second wiring.

[0055] (4)(3) The circuit device described above is The length of the portion of the intermediate wiring that extends in the width direction is the same as the width of the first and second wirings.

[0056] (5) Another circuit device relating to this disclosure is A circuit board on which multiple wires are arranged, Multiple wires and electrically connected coil components, It comprises a coil component and a capacitor element that is electrically connected to it, The coil components are, Including a first coil and a second coil, One end of the first coil is designated as the first terminal, one end of the second coil as the second terminal, and the connection point between the other end of the first coil and the other end of the second coil is designated as the intermediate terminal. The circuit board is A first wire that is electrically connected to the first terminal, A second wire that is electrically connected to the second terminal, An intermediate wire that electrically connects the intermediate terminal and one end of the capacitor element, including, The intermediate wiring has a portion that extends in a width direction perpendicular to the wiring direction of the first and second wirings, and this portion is positioned between the first and second wirings.

[0057] (6)(5) The circuit device described above is The length of the portion of the intermediate wiring that extends in the width direction is the same as the width of the first and second wirings.

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

[0059] (8) The circuit device described in any one of items (1) to (7) is 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) The circuit device described in any one of items (1) to (7) is The coil component includes 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 that magnetically couples them.

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

[0062] (11)(10) The circuit device described above is The connecting component is a ceramic capacitor.

[0063] (12) The circuit device described in any one of items (1) to (11) is In the coil component, the first coil and the second coil are magnetically coupled.

[0064] (13) The circuit board relating to this disclosure is A circuit board capable of mounting multiple wires, a coil component electrically connected to the multiple wires, and a capacitor element electrically connected to the coil component, A first wire that is electrically connected to the first terminal of the first coil included in the coil component, The second wiring is electrically connected to the second terminal of the second coil included in the coil component, An intermediate wire that electrically connects the intermediate terminal connecting the first coil and the second coil to one end of the capacitor element, including, The intermediate wiring has a portion that extends along at least one of the wiring directions of the first wiring and the second wiring, and the length of the intermediate wiring in the direction of extension is longer than the length of the coil component.

[0065] (14) Another circuit board relating to this disclosure is A circuit board capable of mounting multiple wires, a coil component electrically connected to the multiple wires, and a capacitor element electrically connected to the coil component, A first wire that is electrically connected to the first terminal of the first coil included in the coil component, The second wiring is electrically connected to the second terminal of the second coil included in the coil component, An intermediate wire that electrically connects the intermediate terminal connecting the first coil and the second coil to one end of the capacitor element, including, The intermediate wiring has a portion that extends in a width direction perpendicular to the wiring direction of the first and second wirings, and this portion is positioned between the first and second wirings.

[0066] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of the claims are intended to be included. [Explanation of symbols]

[0067] 1 Coil component, 2a, 3a Coil section, 2b, 2d, 3b, 3d Terminals, 2c, 2e, 3c, 3e Electrodes, 4 Housing, 10, 10A~10C Circuit board, 20 Power supply, 30 Power supply IC, 51, 52 Power supply wiring, 60 Intermediate wiring, 81~86 Land electrodes, 100, 100A~100C Filter circuit, C1, C2 Capacitors.

Claims

1. A circuit board on which multiple wires are arranged, A coil component electrically connected to the aforementioned plurality of wires, The coil component is electrically connected to a capacitor element, The aforementioned coil component is Including a first coil and a second coil, One end of the first coil is designated as the first terminal, one end of the second coil as the second terminal, and the connection point between the other end of the first coil and the other end of the second coil is designated as the intermediate terminal. The aforementioned circuit board is A first wire electrically connected to the first terminal, A second wire electrically connected to the second terminal, An intermediate wire that electrically connects the intermediate terminal and one end of the capacitor element, including, The intermediate wiring has a portion that extends along the wiring direction of at least one of the first and second wirings, in the vicinity of at least one of the first and second wirings, separate from the portion that electrically connects the intermediate terminal and one end of the capacitor element, and when the surface of the circuit board on which the coil component is mounted is viewed in plan view, the length of the portion extending in the wiring direction is longer than the length of one side of the coil component.

2. The circuit device according to claim 1, wherein the width of the intermediate wiring perpendicular to the extension direction of the intermediate wiring is narrower than the width of the first wiring and the second wiring.

3. The circuit device according to claim 1, wherein the intermediate wiring further has a portion that extends in a width direction perpendicular to the portion that extends in the wiring direction, and the portion that extends is arranged between the first wiring and the second wiring.

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

5. A circuit board on which multiple wires are arranged, A coil component electrically connected to the aforementioned plurality of wires, The coil component is electrically connected to a capacitor element, The aforementioned coil component is Including a first coil and a second coil, One end of the first coil is designated as the first terminal, one end of the second coil as the second terminal, and the connection point between the other end of the first coil and the other end of the second coil is designated as the intermediate terminal. The aforementioned circuit board is A first wire electrically connected to the first terminal, A second wire electrically connected to the second terminal, An intermediate wire that electrically connects the intermediate terminal and one end of the capacitor element, including, The intermediate wiring has a portion that extends in a width direction perpendicular to the wiring direction of the first and second wirings, separate from the portion that electrically connects the intermediate terminal and one end of the capacitor element, and the portion that extends in the width direction without connecting to other circuits is positioned between the first and second wirings, and when the surface of the circuit board on which the coil component is mounted is viewed from above, the length of the portion that extends in the width direction without connecting to other circuits is longer than the length of one side of the coil component.

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

7. The circuit device according to claim 6, wherein the intermediate wiring further has a portion that extends along the wiring direction of at least one of the first wiring and the second wiring, in the vicinity of at least one of the first wiring and the second wiring, and when the surface of the circuit board on which the coil component is mounted is viewed from above, the length of the portion that extends in the wiring direction is longer than the length of one side of the coil component.

8. The aforementioned 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 direction that magnetically couples.

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

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 is such that the first coil and the second coil are magnetically coupled.

13. A circuit board on which multiple wires are arranged, and a coil component electrically connected to the multiple wires, and a capacitor element electrically connected to the coil component are mounted, A first wire electrically connected to the first terminal of the first coil included in the coil component, A second wire electrically connected to the second terminal of the second coil included in the coil component, An intermediate wire that electrically connects the intermediate terminal connecting the first coil and the second coil to one end of the capacitor element, including, The intermediate wiring has a portion that extends along the wiring direction of at least one of the first and second wirings, in the vicinity of at least one of the first and second wirings, separate from the portion that electrically connects the intermediate terminal and one end of the capacitor element, and when the surface of the circuit board on which the coil component is mounted is viewed from above, the length of the portion extending in the wiring direction is longer than the length of one side of the coil component.

14. A circuit board on which multiple wires are arranged, and a coil component electrically connected to the multiple wires, and a capacitor element electrically connected to the coil component are mounted, A first wire electrically connected to the first terminal of the first coil included in the coil component, A second wire electrically connected to the second terminal of the second coil included in the coil component, An intermediate wire that electrically connects the intermediate terminal connecting the first coil and the second coil to one end of the capacitor element, including, The intermediate wiring has a portion that extends in a width direction perpendicular to the wiring direction of the first and second wirings, separate from the portion that electrically connects the intermediate terminal and one end of the capacitor element, and the portion that extends in the width direction without connecting to other circuits is positioned between the first and second wirings, and when the surface of the circuit board on which the coil component is mounted is viewed from above, the length of the portion that extends in the width direction without connecting to other circuits is longer than the length of one side of the coil component.

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