JP2022118830A - noise filter circuit - Google Patents

Abstract

To provide a noise filter circuit which can be mounted on a print circuit board in which circuit elements are congested, and an electromagnetic noise in a high-frequency band hardly leaks to a power supply side.SOLUTION: A noise filter circuit 100 comprises: a circuit element 1 including a power supply terminal 1A and a ground terminal 1B; a capacitor 2 including a first terminal 2A and a second terminal 2B arranged with an interval from the first terminal 2A in an X-direction; a first wiring pattern 3 connecting the power sully terminal 1A with the first terminal 2A; and a second wiring pattern 4 connecting the ground terminal 1B with the second terminal 2B. The first wiring pattern 3 includes a third wiring part 3C extended from a second wiring part 3B connected to the first terminal 2A in the X-direction. The noise filter circuit 100 is provided so that a noise current flowing through the third wiring part 3C flows in a reverse direction from the noise current flowing through the capacitor 2.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to noise filter circuits.

A capacitor is mounted on a printed circuit board as a filter to bypass electromagnetic noise generated by the operation of mounted integrated circuits (ICs) or large-scale integrated circuits (LSIs) from the power supply pattern to the ground pattern. be done.

However, since the capacitor has an inductance component, the effect of bypassing against electromagnetic noise in a high frequency band is reduced. As a result, electromagnetic noise in a high frequency band tends to leak through the power supply pattern to the power supply side rather than the bypass path.

In the noise filter described in Japanese Patent Application Laid-Open No. 2020-155875 (Patent Document 1), two input loop lines and two output loop lines formed in a power supply pattern are magnetically coupled, and mutual inductance generated between them is reduces the inductance of the capacitor and reduces the total inductance of the capacitor and the power supply pattern.

JP 2020-155875 A

However, the printed circuit board on which the noise filter is mounted requires an area for forming two loop lines. Therefore, it is difficult to mount the noise filter on, for example, a printed circuit board where circuit elements are densely packed.

A main object of the present disclosure is to provide a noise filter circuit that can be mounted on a printed circuit board in which circuit elements are densely packed and that prevents electromagnetic noise in a high frequency band from leaking to the power supply side.

A noise filter circuit according to the present disclosure includes: a circuit element including a power supply terminal and a ground terminal; a capacitor including a first terminal and a second terminal spaced from the first terminal in a first direction; A first wiring pattern connecting the power supply terminal and the first terminal, and a second wiring pattern connecting the ground terminal and the second terminal are provided. At least one of the first wiring pattern and the second wiring pattern has a wiring portion extending in the first direction from a portion connected to the first terminal or the second terminal. The noise current flowing through the wiring portion is provided so as to flow in the opposite direction to the noise current flowing through the capacitor.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a noise filter circuit that can be mounted on a printed circuit board where circuit elements are densely packed and that prevents electromagnetic noise in a high frequency band from leaking to the power supply side.

2 is a plan view showing the noise filter circuit according to Embodiment 1; FIG. FIG. 2 is a plan view showing the configuration of the noise filter circuit shown in FIG. 1 except for capacitors; FIG. 3 is a cross-sectional view seen from arrows III-III in FIG. 2; 2 is a circuit diagram including parasitic components of the noise filter circuit shown in FIG. 1; FIG. 8 is a plan view showing a noise filter circuit according to Embodiment 2; FIG. FIG. 6 is a plan view showing the configuration of the noise filter circuit shown in FIG. 5 except for capacitors; FIG. 7 is a cross-sectional view seen from arrow VII-VII in FIG. 6; 6 is a circuit diagram including parasitic components of the noise filter circuit shown in FIG. 5; FIG. FIG. 11 is a plan view showing a noise filter circuit according to Embodiment 3; FIG. 10 is a plan view showing a wiring portion arranged inside the multilayer substrate of the noise filter circuit shown in FIG. 9; 11 is a cross-sectional view of the noise filter circuit shown in FIGS. 9 and 10; FIG. FIG. 11 is a plan view showing a noise filter circuit according to Embodiment 4; FIG. 10 is a plan view showing a modification of the noise filter circuit according to Embodiments 1 to 3;

Embodiment 1.
As shown in FIGS. 1 to 3, the noise filter circuit 100 is a noise filter circuit mounted on a printed circuit board 10, and includes a circuit element 1, a capacitor 2, and a first wiring that is part of a power supply pattern 11. It mainly includes a pattern 3 and a second wiring pattern 4 that is part of the ground pattern 12 . In addition, in FIG. 3, the capacitor 2 is illustrated with a dashed line.

As shown in FIGS. 1 and 3, the printed circuit board 10 has a first surface 10A and a second surface 10B opposite to the first surface 10A. In the noise filter circuit 100, the circuit element 1, the capacitor 2, the first wiring pattern 3, and the second wiring pattern 4 are arranged on the first surface 10A. The printed board 10 may be a multi-layer board in which a plurality of wiring layers are formed between the first surface 10A and the second surface 10B.

As shown in FIGS. 1 and 2, the circuit element 1 includes a power terminal 1A and a ground terminal 1B. The power supply pattern 11 connects the power supply terminal 1A of the circuit element 1 and the power supply. The ground pattern 12 connects the ground terminal 1B of the circuit element 1 and the ground.

The capacitor 2 is arranged between a first terminal 2A, a second terminal 2B spaced apart from the first terminal 2A in the X direction (first direction), and between the first terminal 2A and the second terminal 2B. portion 2C located. The first terminal 2A is a positive terminal, and the second terminal 2B is a negative terminal. The capacitor 2 constitutes a bypass path for bypassing the electromagnetic noise generated by the circuit element 1 in the noise filter circuit 100 from the power supply pattern 11 to the ground pattern 12 .

As shown in FIGS. 1 and 2, the first wiring pattern 3 connects the power supply terminal 1A of the circuit element 1 and the first terminal 2A of the capacitor 2. As shown in FIGS. The first wiring pattern 3 includes a first wiring portion 3A connected to the power supply terminal 1A, a second wiring portion 3B connected to the first terminal 2A, and a first wiring portion 3A and a second wiring portion 3B. and a third wiring portion 3C for connecting between. The first wiring portion 3A, the third wiring portion 3C, and the second wiring portion 3B are connected in series in this order. The first wiring pattern 3 forms part of the power supply pattern 11 .

As shown in FIGS. 1 and 2 , the power pattern 11 includes a first wiring pattern 3 and a third wiring pattern 5 connected in series with the first wiring pattern 3 . The third wiring pattern 5 is located on the side opposite to the first wiring portion 3A with respect to the second wiring portion 3B. The third wiring pattern 5 is connected to the second wiring portion 3B of the first wiring pattern 3 . In the first wiring pattern 3, only the second wiring portion 3B is connected to other wiring patterns. The first wiring portion 3A, the third wiring portion 3C, the second wiring portion 3B, and the third wiring pattern 5 are connected in series in this order.

As shown in FIGS. 1 to 3, the third wiring portion 3C extends along the X direction from the second wiring portion 3B. As shown in FIGS. 2 and 3, the third wiring portion 3C has one end 3C1 connected to the first wiring portion 3A and the other end 3C2 connected to the second wiring portion 3B. there is One end 3C1 is arranged closer to the second terminal 2B in the X direction than the other end 3C2. The other end 3C2 is connected to the power terminal 1A via the one end 3C1. One end 3C1 is connected to the third wiring pattern 5 via the other end 3C2.

The noise filter circuit 100 is provided so that the noise current flowing through the third wiring portion 3</b>C flows in the opposite direction to the noise current flowing through the capacitor 2 . A noise current flowing through the capacitor 2 flows in the A direction (see FIGS. 1 and 3). The third wiring portion 3C is provided so that noise current flows along the B direction (see FIGS. 2 and 3). The A direction and the B direction are directions along the X direction and are opposite to each other.

As shown in FIGS. 1 and 2, in plan view, the width W2 (see FIG. 2) of the third wiring portion 3C in the direction orthogonal to the X direction (hereinafter referred to as the width direction) is the width direction of the capacitor 2. is equal to the width W1 (see FIG. 1) of . Viewing the noise filter circuit 100 in plan means viewing the noise filter circuit 100 from a direction perpendicular to the first surface 10A. The width W2 being equal to the width W1 means that the ratio of the difference between the two widths to the width W2 (W1-W2)/W2 is 5.0% or less.

As shown in FIGS. 1 and 2, in plan view, the entire third wiring portion 3C overlaps a portion of the portion 2C located between the first terminal 2A and the second terminal 2B of the capacitor 2. is provided in In plan view, the center line of the third wiring portion 3C in the width direction overlaps the center line of the capacitor 2 in the width direction. A portion of the first wiring portion 3A is arranged to overlap another portion of the portion 2C located between the first terminal 2A and the second terminal 2B of the capacitor 2 in plan view. In plan view, the second wiring portion 3B is arranged so as to overlap the first terminal 2A of the capacitor 2 .

As shown in FIG. 3, in cross-sectional view or side view, the distance d between the center line C1 of the capacitor 2 and the center line C2 of the third wiring portion 3C is constant. In cross-sectional view or side view, the center line C1 of the capacitor 2 means a straight line passing through the centers of the first terminal 2A and the second terminal 2B. In cross-sectional view or side view, the center line C2 of the third wiring portion 3C means a straight line passing through the centers of the other end 3C2 and the one end 3C1. That the distance d is constant means that when the distance d is measured at any three points spaced apart in the X direction, the maximum value dmax and the average value dave of the distance d with respect to the average value dave of the distance d The ratio of the difference (dmax-dave)/dave, and the ratio of the difference between the minimum value dmin and the average value dave of the distance d to the average value dave of the distance d (dave-dmin)/dave is 5.0% or less means that

The X-direction length of the third wiring portion 3C is not particularly limited. Even if the length of the third wiring portion 3C in the X direction is short, the inductance L2 of the third wiring portion 3C (see FIG. 4) can reduce the parasitic inductance L1 of the capacitor 2 (see FIG. 4). The length of the third wiring portion 3C in the X direction is, for example, equal to or less than the width W2. Preferably, the length of the third wiring portion 3C in the X direction is set so that the inductance L2 of the third wiring portion 3C can cancel the parasitic inductance L1 of the capacitor 2. FIG.

In plan view, the longitudinal direction of the first wiring portion 3A is parallel to the longitudinal direction of the third wiring pattern 5, for example. The longitudinal direction of the first wiring portion 3A may be orthogonal to the longitudinal direction of the third wiring pattern 5, for example. Planar view WHEREIN: The power supply pattern 11 should just have at least 1 corner|angular part. In plan view, the power supply pattern 11 has, for example, two corners.

As shown in FIGS. 1 and 2, the second wiring pattern 4 connects the ground terminal 1B of the circuit element 1 and the second terminal 2B of the capacitor 2 . The second wiring pattern 4 has a fourth wiring portion 4A connected to the ground terminal 1B and a fifth wiring portion 4B connected to the second terminal 2B. The fourth wiring portion 4A is connected in series with the fifth wiring portion 4B. The second wiring pattern 4 forms part of the ground pattern 12 .

In plan view, the fourth wiring portion 4A and the fifth wiring portion 4B are arranged on the same side with respect to the first wiring pattern 3 . In plan view, the fifth wiring portion 4B is arranged so as to overlap the second terminal 2B of the capacitor 2 .

As shown in FIGS. 1 and 2 , the ground pattern 12 includes a second wiring pattern 4 and a fourth wiring pattern 6 connected in series with the second wiring pattern 4 . The fourth wiring pattern 6 is connected to the fifth wiring portion 4B of the second wiring pattern 4 . In the second wiring pattern 4, for example, only the fifth wiring portion 4B is connected to other wiring patterns. The fourth wiring portion 4A, the fifth wiring portion 4B, and the fourth wiring pattern 6 are connected in series in this order.

As shown in FIGS. 1 and 2, each of the first wiring portion 3A and the second wiring pattern 4 extends in a direction crossing the X direction. Each of the first wiring portion 3A and the second wiring pattern 4 extends, for example, in a direction orthogonal to the X direction. Each of the third wiring pattern 5 and the fourth wiring pattern 6 extends in a direction perpendicular to the X direction. Each of the third wiring pattern 5 and the fourth wiring pattern 6 may extend in the X direction, or may extend in a direction crossing the X direction.

As shown in FIGS. 1 to 3, the first wiring pattern 3 is spaced apart from the second wiring pattern 4 in the direction perpendicular to the X direction.

As shown in FIG. 4, in the noise filter circuit 100 shown in FIGS. 1 to 3, the third wiring portion 3C of the first wiring pattern 3 is magnetically coupled with the capacitor 2 to generate mutual inductance having negative characteristics. designed to occur. Parasitic inductance L1 of capacitor 2 is lower than inductance L4 of third wiring pattern 5 .

The first wiring portion 3A, the second wiring portion 3B, and the third wiring portion 3C of the first wiring pattern 3 are provided, for example, as an integrated wiring layer. The first wiring pattern 3 and the third wiring pattern 5 of the power supply pattern 11 are provided, for example, as an integrated wiring layer. The second wiring pattern 4 and the fourth wiring pattern 6 of the ground pattern 12 are provided, for example, as an integrated wiring layer. In plan view, the ground pattern 12 extends linearly, for example.

The material forming each of the power supply pattern 11 and the ground pattern 12 may be any conductive material, including, for example, copper (Cu).

<effect>
The noise filter circuit 100 includes a circuit element 1 including a power supply terminal 1A and a ground terminal 1B, a capacitor 2 including a first terminal 2A and a second terminal 2B, and a first wiring connecting the power supply terminal 1A and the first terminal 2A. A pattern 3 and a second wiring pattern 4 connecting the ground terminal 1B and the second terminal 2B are provided. The second terminal 2B is spaced apart from the first terminal 2A in the X direction. The first wiring pattern 3 has a second wiring portion 3B connected to the first terminal 2A and a third wiring portion 3C extending from the second wiring portion 3B in the X direction. The noise filter circuit 100 is provided so that the noise current flowing through the third wiring portion 3</b>C flows in the opposite direction to the noise current flowing through the capacitor 2 .

That is, the noise filter circuit 100 is provided so that the third wiring portion 3C of the first wiring pattern 3 is magnetically coupled with the capacitor 2 to generate mutual inductance having a negative characteristic. Therefore, the total inductance between the capacitor 2 and the first wiring pattern 3 in the noise filter circuit 100 is equal to reduced compared to the total inductance. Therefore, in the noise filter circuit 100, the electromagnetic noise in the high frequency band is less likely to leak to the power source side (that is, the third wiring pattern 5) than to the first wiring pattern 3.

Furthermore, in the noise filter circuit 100, only by forming the third wiring part 3C capable of magnetically coupling with the capacitor 2 in the first wiring pattern 3 without forming a plurality of loop lines in the power supply pattern 11, , the electromagnetic noise leaking to the third wiring pattern 5 is reduced. Therefore, in plan view, the area of the power supply pattern 11 of the noise filter circuit 100 can be made smaller than the area of the power supply pattern in which a plurality of loop lines are formed. As a result, the noise filter circuit 100 can be mounted even on the printed circuit board 10 where the circuit elements 1 are densely packed.

Preferably, the mutual inductance between the third wiring portion 3C and the capacitor 2 is provided so as to cancel out the parasitic inductance of the capacitor 2 . In this case, the impedance of the bypass path that bypasses the electromagnetic noise from the power supply pattern 11 to the ground pattern 12 in the noise filter circuit 100 is equivalent to the impedance of only the capacitance C of the capacitor 2 . In such a noise filter circuit 100 , the effect of bypassing the electromagnetic noise in the high frequency band by the capacitor 2 is maximized, so the electromagnetic noise in the high frequency band is less likely to leak through the third wiring pattern 5 .

Preferably, the width W2 of the third wiring portion 3C is equal to the width W1 of the capacitor 2 in plan view. This is qualitatively derived based on the following equations (1) to (3).

First, in a two-layer board, the wiring inductance is represented by the following equation (1). l is the length of the conductor (unit: mm), w is the width of the conductor (unit: mm), and t is the thickness of the copper foil (unit: mm). Also, if the width and thickness of each of the capacitor 2 and the third wiring portion 3C are ignored and both are regarded as parallel conductors parallel to each other, the mutual inductance M12 of both is expressed by the following equation ( ₂ ): be. μ ₀ is the vacuum permeability. r is the distance between the line elements _dx1 and dx2 of each parallel conductor, d is the shortest distance between the _two parallel conductors, and r and d are represented by the following equation (3). Equation (2) integrates over the length of each line element dx ₁ and dx ₂ for each line element dx ₁ and dx ₂ respectively.

The narrower the width W2 of the third wiring portion 3C than the width W1 of the capacitor 2, the higher the inductance L2 of the third wiring portion 3C. As a result, a relatively large noise voltage is generated. When the width W2 of the third wiring portion 3C is equal to the width W1 of the capacitor 2 in plan view, a relatively large noise voltage is less likely to occur than when the width W2 is narrower than the width W1.

Further, the wider the width W2 of the third wiring portion 3C than the width W1 of the capacitor 2, the more likely the noise current flowing through the third wiring portion 3C spreads in the width direction of the third wiring portion 3C. Magnetic coupling with the capacitor 2 may weaken. When the width W2 of the third wiring portion 3C is equal to the width W1 of the capacitor 2 in plan view, the total inductance of the capacitor 2 and the first wiring pattern 3 is reduced compared to when the width W2 is wider than the width W1. can be reduced.

In the power supply pattern 11 of the noise filter circuit 100, only the second wiring portion 3B connected to the first terminal 2A is connected to the third wiring pattern 5. As shown in FIG. The third wiring portion 3C is connected to the third wiring pattern 5 only through the second wiring portion 3B, and is not directly connected to the third wiring pattern 5. As shown in FIG. If the third wiring portion 3C is directly connected to the third wiring pattern 5, the noise current may flow to other circuit elements via the third wiring pattern 5 without passing through the capacitor 2.

Preferably, the third wiring portion 3C is arranged so as to overlap the capacitor 2 in plan view. Such a noise filter circuit 100 can be made smaller in plan view than a noise filter circuit 103 (see FIG. 12, details of which will be described later) in which the third wiring portion 3C is arranged side by side with the capacitor 2. .

Embodiment 2.
The noise filter circuit 101 according to the second embodiment shown in FIGS. 5 and 6 has basically the same configuration and the same effect as the noise filter circuit 100, but the second wiring pattern 4 is connected to the second terminal. It differs from the noise filter circuit 100 in that it has a sixth wiring portion 4C extending in the X direction from a fifth wiring portion 4B connected to 2B.

The first wiring pattern 3 includes, for example, the first wiring portion 3A and the second wiring portion 3B, and does not include the third wiring portion 3C shown in FIG. The second wiring portion 3B is connected in series with the first wiring portion 3A.

As shown in FIGS. 6 and 7, the sixth wiring portion 4C has one end 4C1 connected to the fourth wiring portion 4A and the other end 4C2 connected to the fifth wiring portion 4B. there is One end 4C1 is arranged closer to the first terminal 2A in the X direction than the other end 4C2. The other end 4C2 is connected to the ground terminal 1B via one end 4C1. The fifth wiring portion 4B, the sixth wiring portion 4C, and the fourth wiring portion 4A are connected in series in this order.

Preferably, in the second wiring pattern 4 of the noise filter circuit 101, only the fourth wiring portion 4A is connected to other wiring patterns. That is, only the portion of the second wiring pattern 4 that connects the portion connected to the ground terminal 1B and the one end 4C1 of the sixth wiring portion 4C is connected to another wiring pattern. A portion of the fourth wiring portion 4A connected to one end 4C1 of the sixth wiring portion 4C is connected to the fourth wiring pattern 6 . The fifth wiring portion 4B, the sixth wiring portion 4C, the fourth wiring portion 4A, and the fourth wiring pattern 6 are connected in series in this order.

In plan view, the fourth wiring portion 4A and the fourth wiring pattern 6 extend linearly, for example. In plan view, the sixth wiring portion 4C protrudes from the fourth wiring portion 4A and the fourth wiring pattern 6 in the X direction.

In plan view, the entire sixth wiring portion 4C is provided so as to partially overlap the portion 2C located between the first terminal 2A and the second terminal 2B of the capacitor 2 . In plan view, the widthwise centerline of the sixth wiring portion 4</b>C overlaps with the widthwise centerline of the capacitor 2 . In a plan view, part of the fourth wiring portion 4A is arranged so as to overlap another part of the portion 2C located between the first terminal 2A and the second terminal 2B of the capacitor 2 .

As shown in FIGS. 5 and 6, in plan view, the width W2 (see FIG. 6) of the sixth wiring portion 4C in the direction perpendicular to the X direction is equal to the width W1 (see FIG. 6) of the capacitor 2 in the direction perpendicular to the X direction. 5).

As shown in FIG. 8, in the noise filter circuit 101 shown in FIGS. 5 to 7, the sixth wiring portion 4C of the second wiring pattern 4 is magnetically coupled with the capacitor 2 to generate mutual inductance having negative characteristics. designed to occur.

Only the fourth wiring portion 4A of the second wiring pattern 4 is connected to other wiring patterns. In this way, the noise current flowing from the second terminal 2B of the capacitor 2 to the fifth wiring portion 4B flows through the sixth wiring portion 4C and then to the fourth wiring portion 4A or another wiring pattern. Become. On the other hand, when the fifth wiring portion 4B or the sixth wiring portion 4C is connected to another wiring pattern, the noise current flowing from the second terminal 2B of the capacitor 2 to the fifth wiring portion 4B is It may flow to the fourth wiring portion 4A or another wiring pattern without flowing to the portion 4C. That is, when only the fourth wiring portion 4A of the second wiring pattern 4 is connected to another wiring pattern, the fifth wiring portion 4B or the sixth wiring portion 4C is connected to the other wiring pattern. Compared to the case, the total inductance between the capacitor 2 and the first wiring pattern 3 can be reduced more effectively.

When the inductance L4 of the fourth wiring portion 4A of the second wiring pattern 4 is lower than the inductance L6 of the fourth wiring pattern 6, at least one of the fifth wiring portion 4B and the sixth wiring portion 4C is may be connected to the wiring pattern of

Embodiment 3.
The noise filter circuit 102 shown in FIGS. 9 and 10 has basically the same configuration as the noise filter circuit 101 and has the same effect. differs from the noise filter circuit 101 in that it is arranged inside the .

As shown in FIG. 11, the printed board 10 is a multi-layer board having a plurality of wiring layers formed between the first surface 10A and the second surface 10B.

The second wiring pattern 4 includes a fourth wiring portion 4A and a fifth wiring portion 4B arranged on the first surface 10A, a seventh wiring portion 4D arranged inside the printed circuit board 10, and a fourth wiring portion 4A. and a plurality of vias 4E and 4F connecting each of the fifth wiring portion 4B and the seventh wiring portion 4D.

In a plan view, the seventh wiring portion 4D includes a sixth wiring portion 4C arranged so as to partially overlap a portion 2C of the capacitor 2 located between the first terminal 2A and the second terminal 2B, and a sixth wiring portion 4C. An eighth wiring portion 4G arranged so as to overlap a part of the fourth wiring portion 4A and the second wiring portion 3B, and a ninth wiring portion 4H arranged so as to overlap at least a part of the fifth wiring portion 4B. including.

The via 4E connects the fourth wiring portion 4A and the eighth wiring portion 4G. The via 4F connects the fifth wiring portion 4B and the ninth wiring portion 4H. In plan view, the via 4F is arranged so as not to overlap the second terminal 2B of the capacitor 2, for example. Note that the via 4F may be arranged so as to overlap the second terminal 2B of the capacitor 2 in plan view.

The sixth wiring portion 4C has one end 4C1 connected to the eighth wiring portion 4G and the other end 4C2 connected to the ninth wiring portion 4H. One end 4C1 of the sixth wiring portion 4C is connected to the fourth wiring portion 4A via the eighth wiring portion 4G and the via 4E. The other end 4C2 of the sixth wiring portion 4C is connected to the fifth wiring portion 4B via the ninth wiring portion 4H and the via 4F. One end 4C1 is arranged closer to the first terminal 2A in the X direction than the other end 4C2. The other end 4C2 is connected to the ground terminal 1B via one end 4C1.

In plan view, the fifth wiring portion 4B is arranged on the opposite side of the first wiring pattern 3 to the fourth wiring portion 4A.

The fifth wiring portion 4B, the via 4F, the ninth wiring portion 4H, the sixth wiring portion 4C, the eighth wiring portion 4G, the via 4E, and the fourth wiring portion 4A are connected in series in this order.

Note that the power supply pattern 11 of the noise filter circuit 102 shown in FIGS. 9 and 10 extends one-dimensionally in a plan view and is provided in a so-called line shape, but is not limited to this. The power supply pattern 11 of the third embodiment may spread two-dimensionally in a plan view, and may be provided in a so-called solid pattern. The fifth wiring portion 4B and the seventh wiring portion 4D can be formed so as not to interfere with the solid power pattern 11 formed on the first surface 10A.

Further, the noise filter circuit according to the third embodiment has basically the same configuration as the noise filter circuit 100 and has the same effect, but the third wiring portion 3C of the first wiring pattern 3 is the printed circuit board 10. It may differ from the noise filter circuit 100 in that it is arranged inside. In this case, the first wiring pattern 3 has the same configuration as the second wiring pattern 4 shown in FIGS. 9 and 10, and the second wiring pattern 4 is the first wiring pattern shown in FIGS. 3 may have the same configuration.

Embodiment 4.
The noise filter circuit 103 according to the fourth embodiment shown in FIG. 12 has basically the same configuration as the noise filter circuit 100 and has the same effect. It differs from the noise filter circuit 100 in that they are arranged side by side.

The third wiring portion 3C extends along the Y direction (first direction) from the second wiring portion 3B. Planar view WHEREIN: The centerline C3 of the 3rd wiring part 3C is extended in the same straight line shape as the centerline of the 1st wiring part 3A, for example. In plan view, the distance L between the center line C2 of the capacitor 2 and the center line C3 of the third wiring portion 3C is equal to or less than the width W1 of the capacitor 2 orthogonal to the Y direction.

As the width of the third wiring portion 3C perpendicular to the Y direction increases, the distance L increases. As the width of the third wiring portion 3C increases, the parasitic inductance of the third wiring portion 3C is reduced, but the noise current flows in a wide area, and the mutual inductance reduces the inductance of the capacitor 2. reduce the effect of

The size of the capacitor 2, the width of each of the first wiring portion 3A and the third wiring portion 3C, and the distance L are determined from the capacitor 2 in the noise filter circuit 103 based on the above equations (1) to (3). It is set so that the total inductance with the first wiring pattern 3 can be reduced compared to that in a noise filter circuit in which the first wiring pattern 3 does not include the third wiring portion 3C.

Further, the noise filter circuit according to the fourth embodiment has basically the same configuration as the noise filter circuit 101 or the noise filter circuit 102 and has the same effect, but the sixth wiring portion 4C is the capacitor 2 in plan view. may be different from the noise filter circuit 101 or the noise filter circuit 102 in that they are arranged side by side.

<Modification>
In the noise filter circuits 100 to 102 according to Embodiments 1 to 3, the entirety of the third wiring portion 3C or the sixth wiring portion 4C is arranged so as to overlap the capacitor 2 in plan view, but the third wiring portion Only a part of each width direction of 3C or 4 C of 6th wiring parts may be arrange|positioned so that the capacitor|condenser 2 may be overlapped. In plan view, each center line of the third wiring portion 3C or the sixth wiring portion 4C overlaps the capacitor 2, for example.

In the noise filter circuit 103 according to the fourth embodiment, the entire third wiring portion 3C is arranged so as not to overlap the capacitor 2 in plan view, but only a part of the third wiring portion 3C in the width direction is It may be arranged so as to overlap with the capacitor 2 .

The noise filter circuits 100-103 according to Embodiments 1-4 may be combined with each other.

For example, the second wiring pattern 4 of the noise filter circuit 100, like the noise filter circuits 101 and 102, may include a sixth wiring portion 4C. In other words, each of the first wiring patterns 3 of the noise filter circuits 101 and 102 may include the third wiring portion 3C like the noise filter circuit 100 does. In the noise filter circuit 104 shown in FIG. 13, the first wiring pattern 3 includes the third wiring portion 3C, and the second wiring pattern 4 includes the sixth wiring portion 4C. In the noise filter circuit 104, a part of the portion 2C located between the first terminal 2A and the second terminal 2B of the capacitor 2 in plan view is arranged so as to partially overlap the third wiring portion 3C. The other part of the portion 2C located between the first terminal 2A and the second terminal 2B of 2 is arranged so as to overlap with the sixth wiring portion 4C.

For example, the sixth wiring portion 4C of the noise filter circuit 102 may be arranged side by side with the capacitor 2 in plan view.

Such a noise filter circuit can also achieve the same effect as the noise filter circuits 100-103.

Although the embodiment of the present disclosure has been described as above, it is also possible to modify the above-described embodiment in various ways. Also, the scope of the present disclosure is not limited to the above-described embodiments. The scope of the present disclosure is indicated by the claims, and is intended to include all changes within the meaning and range of equivalents to the claims.

1 circuit element, 1A power supply terminal, 1B ground terminal, 2 capacitor, 2A first terminal, 2B second terminal, 3 first wiring pattern, 3A first wiring portion, 3B second wiring portion, 3C third wiring portion, 3C1 , 4C1 one end, 3C2, 4C2 other end, 4 second wiring pattern, 4A fourth wiring section, 4B fifth wiring section, 4C sixth wiring section, 4D seventh wiring section, 4E, 4F via, 4G eighth wiring section , 4H Ninth wiring portion 5 Third wiring pattern 6 Fourth wiring pattern 10 Printed circuit board 10A First surface 10B Second surface 11 Power supply pattern 12 Ground pattern 100, 101, 102, 103, 104 noise filter circuit.

Claims (9)

a circuit element including a power terminal and a ground terminal;
a capacitor including a first terminal and a second terminal spaced from the first terminal in a first direction;
a first wiring pattern connecting the power supply terminal and the first terminal;
a second wiring pattern connecting the ground terminal and the second terminal;
at least one of the first wiring pattern and the second wiring pattern has a wiring portion extending in the first direction from a portion connected to the first terminal or the second terminal;
A noise filter circuit, wherein a noise current flowing through the wiring portion is arranged to flow in a direction opposite to a noise current flowing through the capacitor. 2. The noise filter circuit according to claim 1, wherein said wiring portion is arranged so as to overlap with said capacitor in plan view. 3. The noise filter circuit according to claim 2, wherein a width of said wiring portion is equal to a width of said capacitor in a direction perpendicular to said first direction in plan view. 2. The noise filter circuit according to claim 1, wherein said wiring portion is arranged side by side with said capacitor in plan view. It has a first surface on which the circuit element and the capacitor are mounted and a second surface located opposite to the first surface, and a plurality of wirings between the first surface and the second surface. further comprising a multilayer substrate comprising layers,
5. The noise filter circuit according to claim 1, wherein said wiring portion is arranged inside said multilayer substrate. The first wiring pattern includes a first wiring portion connected to the power supply terminal, a second wiring portion connected to the first terminal, and a third wiring portion extending from the second wiring portion in the first direction. It has a wiring part,
The first wiring portion and the second wiring portion are connected in series via the third wiring portion,
In the third wiring portion, one end connected to the first wiring portion is arranged closer to the second terminal in the first direction than the other end connected to the second wiring portion, A noise filter circuit according to any one of claims 1 to 5. 7. The noise filter circuit according to claim 6, wherein in said first wiring pattern, only said second wiring portion is connected to another wiring pattern. The second wiring pattern includes a fourth wiring portion connected to the ground terminal, a fifth wiring portion connected to the second terminal, and a sixth wiring portion extending from the fifth wiring portion in the first direction. It has a wiring part,
The fourth wiring portion and the fifth wiring portion are connected in series via the sixth wiring portion,
In the sixth wiring portion, one end connected to the fourth wiring portion is arranged closer to the first terminal in the first direction than the other end connected to the fifth wiring portion, A noise filter circuit according to any one of claims 1 to 5. 9. The noise filter circuit according to claim 8, wherein in said second wiring pattern, only said fourth wiring portion is connected to another wiring pattern.

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