Electronic circuit and circuit board

Abstract

This invention provides an electronic circuit and a circuit board that achieves miniaturization by utilizing the interaction between adjacent arranged structures. The electronic circuit has a plurality of independent electronic circuits arranged in a row, each having: a first conductor post that extends along the stacking direction and is connected to the ground line of a first layer of any one of a plurality of conductor layers stacked in a separate state; a conductor line that extends in a strip shape in a second layer of any one of the plurality of conductor layers, which is different from the first layer, and is connected to the conductor post, with an open end away from the conductor post; and a second conductor post that is connected to the conductor line but not connected to the ground line and extends along the stacking direction. Each of the adjacent first and second independent electronic circuits in the plurality of independent electronic circuits has at least one pair of second conductor posts formed at adjacent positions without being separated by the conductor lines of either the first or second independent electronic circuit.

Description

Technical Field

[0001] This invention relates to an electronic circuit and a circuit board. Background Technology

[0002] Techniques for suppressing electromagnetic noise propagation by forming EBG (Electromagnetic Band Gap Structure) structures on circuit boards are known. EBG structures require a relatively large area on the circuit board and involve arranging multiple identical structures, thus miniaturization has become a challenge.

[0003] For example, Patent Document 1 proposes a miniaturized EBG structure that forms two layers of vortex-shaped conductor lines and connects them through vias.

[0004] Furthermore, Patent Document 2 proposes that in addition to the layer with conductor lines and the ground layer, a third layer is formed, thereby achieving a miniaturized EBG structure.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-134809

[0006] Patent Document 2: Japanese Patent Application Publication No. 2013-255259 Summary of the Invention

[0007] The purpose of this invention is to provide an electronic circuit and circuit board that achieves miniaturization by utilizing the interaction between adjacent arranged structures.

[0008] The invention involved in Scheme 1 is an electronic circuit, characterized in that,

[0009] A plurality of independent electronic circuits are arranged in a plurality of ways, each of the plurality of independent electronic circuits having:

[0010] The first conductor post is connected to the ground wire of the first layer of any one of the plurality of conductor layers stacked in a separate state and extends along the stacking direction.

[0011] A conductor line, extending in a strip shape in a second layer different from the first layer in any of the plurality of conductor layers, is connected to the conductor post, and its end away from the conductor post is an open end; and

[0012] The second conductor post is connected to the conductor line but not to the ground line, and extends along the stacking direction.

[0013] Each of the plurality of independent electronic circuits, including the first and second independent electronic circuits adjacent to each other, has at least one pair of the second conductor posts formed at adjacent positions on the conductor lines of the first and second independent electronic circuits without being separated from each other.

[0014] The invention involved in Scheme 2 is the electronic circuit described in Scheme 1, characterized in that at least one of the plurality of independent electronic circuits is a circuit for suppressing electromagnetic noise of the same frequency.

[0015] The invention involved in Scheme 3 is the electronic circuit described in Scheme 2, characterized in that the conductor line of each of the plurality of independent electronic circuits is a line whose end is different from the open end of the conductor line and is connected to the conductor post.

[0016] The invention involved in Scheme 4 is the electronic circuit described in Scheme 3, characterized in that the conductor line is a line that extends continuously or intermittently from one end toward the other end in the same direction of rotation.

[0017] The invention involved in Scheme 5 is a circuit board, characterized in that it is equipped with the electronic circuit described in any one of Schemes 1 to 4.

[0018] Invention Effects

[0019] According to the electronic circuits of the first and second embodiments of the present invention, and the circuit board of the fifth embodiment of the present invention, miniaturization is achieved.

[0020] According to the electronic circuit of the third aspect of the present invention, the frequency band of suppressing propagating electromagnetic noise can be reduced to the maximum extent, with the same conductor line length.

[0021] According to the fourth aspect of the present invention, the electronic component can be miniaturized compared to shapes other than a vortex shape. Attached Figure Description

[0022] The embodiments of the present invention will be described in detail with reference to the following figures.

[0023] Figure 1 This is a schematic diagram illustrating an example of a circuit that constitutes a unit of the existing EBG structure;

[0024] Figure 2 This is a diagram representing the equivalent circuit of the EBG structure, i.e., the distributed constant circuit;

[0025] Figure 3 This is a graph representing the frequency response of the admittance Y;

[0026] Figure 4It is a diagram schematically representing the transmission characteristics relative to frequency;

[0027] Figure 5 This is a schematic diagram representing various shapes of EBG structures;

[0028] Figure 6 This is a diagram showing a unit of the EBG structure constituting an electronic circuit as described in the first embodiment of the present invention.

[0029] Figure 7 This indicates that there are four arrangements. Figure 6 The diagram shows a schematic of the EBG structure of a single circuit unit.

[0030] Figure 8 This is a diagram showing the equivalent circuit of the EBG structure when vias that function as capacitors are added, i.e., the distributed constant circuit.

[0031] Figure 9 This is an illustration of the effect of adding a pair of adjacent vias between adjacent unit circuits;

[0032] Figure 10 This is a top view of the EBG structure in various implementations.

[0033] Symbol Explanation

[0034] 10-Circuit board, 11-Ground line, 12-Via, 13-Short post, 14-Via. Detailed Implementation

[0035] Here, we will first explain the EBG structure (Electromagnetic Band Gap Structure). The EBG structure is a periodic structure with a band gap that suppresses the propagation of electromagnetic waves. By forming an EBG structure near an electronic circuit on a circuit board that emits electromagnetic noise, the propagation of electromagnetic noise emitted from that electronic circuit is suppressed.

[0036] Figure 1 This is a schematic diagram illustrating an example of a circuit that constitutes a unit of the existing EBG structure.

[0037] Here, a circuit board with multiple conductor layers is used, and the first layer of any one of these multiple layers is the ground line 11. A conductor post called a via 12, which extends along the stacking direction and is connected to the ground line 11 of the first layer, is formed here. Furthermore, a conductor line called a short post 13, which extends in a spiral shape, is formed in a second layer different from the first layer. One end 13a of the short post 13 is connected to the via 12. The end 13b of the short post 13, away from the via 12, is open, i.e., an open end not directly connected to other conductors. By arranging multiple such conductors on the circuit board... Figure 1 The unit structure shown constitutes the EBG structure.

[0038] Here, the Figure 1 The short post 13 shown is not a vortex shape composed of curves, but rather a conductor line that extends while intermittently bending in the same direction of rotation from one end connected to the via 12 toward the other end. Specifically, the short post 13 is a conductor line that extends while intermittently bending at 90° in the same direction of rotation. Here, not only vortex shapes composed of continuous curves, but also shapes that extend while intermittently bending at 45° or 90° are also referred to as vortex shapes.

[0039] Figure 2 This is a diagram representing the equivalent circuit of the EBG structure, i.e., the distributed constant circuit.

[0040] The equivalent circuit of the EBG structure is based on this Figure 2 The circuit shown represents the distributed constant. Here, inductor L1 and capacitor C1 are the inductance and capacitance of the transmission path, respectively. The inductor L1 has less to do with the frequency characteristics of suppressing electromagnetic noise; the portion enclosed by the dashed line is related to its frequency characteristics.

[0041] The admittance Y of the portion enclosed by the dashed line

[0042] [Formula 1]

[0043]

[0044] To express.

[0045] (in,

[0046] Zstub represents the impedance of short post 13.

[0047] C1 is the capacitance between adjacent unit cells.

[0048] L2 is the inductor of via 12.

[0049] ω is the angular frequency

[0050] j is the symbol for a complex number.

[0051] Figure 3 This is a graph representing the frequency response of the admittance Y. Figure 3 The vertical axis represents the imaginary component Im(Y) of the admittance Y, and the horizontal axis represents the frequency (GHz).

[0052] In Figure 3 The region where Im(Y) is negative, as indicated by the added shading, is called the inductive region, and the region where it is positive is called the capacitive region. Furthermore, in this EBG structure, the propagation of electromagnetic noise at frequencies within the inductive region, i.e., the frequency region where Im(Y) is negative, is suppressed.

[0053] Here, the frequency region where Im(Y) becomes negative is related to the length of the short bar 13. The longer the short bar 13 is, the more the pattern of the frequency characteristic shifts to the lower frequency side, and the shorter the short bar 13 is, the more the pattern of the frequency characteristic shifts to the higher frequency side.

[0054] Figure 4 This is a schematic diagram illustrating the transmission characteristics relative to frequency. Figure 4 In this context, the lower the transmission characteristics, the more effectively noise propagation is suppressed.

[0055] The center frequency f0 at which noise propagation is suppressed is approximately...

[0056] [Formula 2]

[0057] f0=c / (4×length of the short bar)··(2)

[0058] (Where, c is the speed of light.)

[0059] To express.

[0060] In Figure 4 In the diagram, when curve A is taken as the reference, if a short bar is used, as shown in curve B, the frequency at which noise propagation is suppressed shifts towards the higher frequency side. If a long bar is used, as shown in curve C, the frequency at which noise propagation is suppressed shifts towards the lower frequency side. This means that to suppress the propagation of low-frequency noise, a long bar is needed, thus requiring a wider area. Therefore, miniaturization of the EBG structure is required.

[0061] Figure 5 This is a schematic diagram representing various shapes of EBG structures.

[0062] Figure 5 (A) shows an EBG structure with a plurality of units of short linear columns 13 having the vortex shape described so far. Figure 1Similarly, the short post 13 shown here is a conductor line that extends intermittently at 90° from one end connected to the via 12 toward the other end in the same direction of rotation. However, as long as it is a vortex shape as defined above, the EBG structure can also be constructed in any vortex shape.

[0063] and, Figure 5 (B) shows an EBG structure consisting of a plurality of short linear columns 13 arranged in a so-called meandering shape, extending simultaneously in a left-right reciprocating pattern. Figure 5 (B) shows a meandering shape in which the direction of extension is reversed by two bends at 90° along the same direction of rotation, but it is not limited to this. For example, it could be a shape that reverses while depicting a curve, or it could be a shape in which the direction of extension is reversed by four bends at 45°. One end 13a of each unit's short post 13 is connected to the through hole 12 of each unit. Moreover, each short post 13 extends in a meandering shape, with the end 13b on the side away from the through hole 12 becoming an open end.

[0064] and, Figure 5 (C) shows an EBG structure with a plurality of units having short posts 13 extending in a straight line. One end 13a of each unit's short post 13 is connected to a via 12 of that unit. Moreover, each short post 13 extends in a straight line, with the end 13b on the side away from the via 12 being an open end.

[0065] As illustrated in these examples, short posts 13 of various shapes can be used in the EBG structure. However, the length of the short post 13 from the point where it connects to the via 12 to the open end is related to the frequency of noise propagation that needs to be suppressed. To suppress low-frequency noise, a longer short post is required. Therefore, to suppress low-frequency noise, a short post 13 is formed that connects to the via 12 at one end 13a, which is advantageous in terms of miniaturization.

[0066] Referring to the above description of the EBG structure, the embodiments of the present invention will be described below.

[0067] Figure 6 This is a diagram showing a unit of the EBG structure constituting an electronic circuit, as described in the first embodiment of the present invention.

[0068] and, Figure 7 This indicates that there are four arrangements. Figure 6 The diagram shows a schematic of the EBG structure of a single unit circuit. Here, Figure 7 (A) is a schematic sectional view. Figure 7 (B) is a schematic top view.

[0069] Here, with Figure 1Similarly, the existing example shown employs a circuit board 10 having multiple conductor layers, with the first layer of any one of these layers serving as a ground line 11. Here, a conductor post called a via 12 is formed, extending along the stacking direction and connected to the first layer, i.e., the ground line 11. Furthermore, a conductor line called a short post 13, extending in a spiral shape, is formed in a second layer different from the first layer. In this embodiment, the conductor line employs a spiral shape that extends while changing direction at 90°. However, it is not limited to a spiral shape that extends while changing direction at 90°; as defined above, any conductor line that extends while continuously or intermittently bending from one end to the other in the same direction of rotation is acceptable.

[0070] In Figure 6 In the circuit shown, vias 14, connected to the short posts 13 and extending along the stacking direction, are provided at multiple points along the middle of the extension of the short posts 13. However, as... Figure 7 As shown in (A), these vias 14, unlike the via 12 located at the center of the vortex, are not connected to the ground wire 11. The via 12, which is connected to both the short post 13 located at the center of the vortex and the ground wire 11, corresponds to an example of the first conductor post described in this invention. The vias 14, which are connected to the short post 13 but not to the ground wire 11, correspond to an example of the second conductor post described in this invention.

[0071] Here, as Figure 7 As shown in (B), when a plurality of unit circuits are arranged, the vias 14 not connected to the ground wire 11 are positioned adjacent to each other in the conductor lines of the short posts 13 without being separated by any other conductor lines. However, since unit circuits of the same shape are arranged here, there are also vias 14 in the corner unit circuits where no unit circuit is located next to them and there are no paired objects. The adjacent vias 14 of two adjacent unit circuits act as capacitors, thereby generating capacitance. If the two vias 14 are separated to the extent that a conductor line of the short posts 13 can be arranged between them, a sufficient capacitance cannot be generated. For example, it is preferable that the two vias 14 are close to each other to the extent that a conductor line of the short posts 13 cannot be arranged between them.

[0072] Figure 8 This is a diagram showing the equivalent circuit of the EBG structure when vias that function as capacitors are added, i.e., the distributed constant circuit.

[0073] In Figure 8 In, with Figure 2 Compared to the equivalent circuit of the existing EBG structure shown, i.e. the distributed constant circuit, a capacitor C2 is added.

[0074] The admittance Y of the portion of the equivalent circuit enclosed by the dashed line is...

[0075] [Formula 3]

[0076]

[0077] (Where, ·· / / ·· indicates parallel connection.)

[0078] To express.

[0079] Figure 9 This is an illustration of the effect of adding a pair of adjacent vias between adjacent unit circuits. Figure 9 (A) Figure 9 In (B), the horizontal axis represents frequency, and the vertical axis represents transmission characteristics. Here, the lower the transmission characteristics, the more noise propagation is hindered.

[0080] Based on the imaginary part Im(Y) of the admittance Y, expressed in equation (1) above, calculated from the equivalent circuit of the existing EBG structure, the transmission characteristics are as follows: Figure 9 The curve A is shown in (A). Here, we want to prevent the propagation of noise with center frequency f0.

[0081] Based on the imaginary part Im(Y) of the admittance Y expressed by the above equation (3) when vias 14 are formed in close proximity in adjacent unit circuits, the transmission characteristics are as follows: Figure 9 As shown in curve D of (A), the bandwidth that can block the propagation of noise is widened.

[0082] Therefore, miniaturization of the EBG structure is considered based on widening the bandwidth by forming via 14. If miniaturization is performed, then as follows... Figure 9 As shown by curve E in (B), the frequency band that can prevent noise propagation shifts to the higher frequency side. Here, we want to prevent the propagation of noise at the center frequency f0.

[0083] Therefore, even if the frequency band is shifted to the higher frequency side to a degree that can be represented by curve E, the performance of preventing the propagation of noise at the center frequency f0 is maintained.

[0084] In other words, by forming via 14, it is possible to maintain the performance of blocking the propagation of noise at the center frequency f0, and to miniaturize the EBG structure.

[0085] When used as an example Figure 6 , Figure 7 When using the EBG structure of the shape shown, it was confirmed that the area of ​​the EBG structure could be reduced by more than 20%.

[0086] The aim here is to arrange identical unit circuits when arranging a plurality of unit circuits, but as long as the line width of the short post 13 and the length of the short post are within ±60% and ±15% respectively, it is possible to achieve the goal of preventing the propagation of noise with a common center frequency f0 among them.

[0087] Figure 10 This is a top view of the EBG structure in various implementations.

[0088] exist Figure 10 Example of an EBG structure with a vortex-shaped conductor line is shown in (A). In this example, vias 14, which are not connected to the ground line 11, are arranged at four positions (top, bottom, left, and right) in each unit circuit.

[0089] exist Figure 10 (B) shows another example of an EBG structure with a vortex-shaped conductor line. In this example, vias 14, which are not connected to ground 11, are located at both the top and bottom of each unit circuit.

[0090] As these examples show, there is no limit to the number of vias 14.

[0091] exist Figure 10 An example of an EBG structure with a short, meandering column 13 is shown in (C). Figure 10 In (C), two vias 14 are formed on the top and bottom sides, with the two unit circuits above and below each other.

[0092] exist Figure 10 Example of an EBG structure with a short, straight column 13 is shown in (D). Figure 10 In (D), with the upper and lower unit circuits adjacent to each other, through holes 14 are formed at the central position and the open end in each unit circuit.

[0093] As these examples demonstrate, the present invention can be applied regardless of the shape of the short bar 13.

[0094] The embodiments of the present invention described above are provided for illustrative purposes. Furthermore, these embodiments do not encompass the entirety of the invention, nor do they limit the invention to the disclosed methods. It will be apparent to those skilled in the art that various modifications and variations will be readily understood. These embodiments were chosen and described to most readily explain the principles and applications of the invention. Thus, those skilled in the art can understand the invention through various modifications that are assumed to be optimized for specific uses of various embodiments. The scope of the invention is defined by the foregoing claims and their equivalents.

Claims

1. An electronic circuit, characterized in that, It has a plurality of independent electronic circuits arranged in a row, each of the plurality of independent electronic circuits having: The first conductor post is connected to the ground wire of the first layer of any one of the plurality of conductor layers stacked in a separate state and extends along the stacking direction. A conductor line, extending in a strip shape in a second layer different from the first layer in any of the plurality of conductor layers, is connected to the conductor post, and its end away from the conductor post is an open end; and The second conductor post is connected to the conductor line but not to the ground line, and extends along the stacking direction. Each of the first and second independent electronic circuits, which are adjacent to each other, has at least one pair of second conductor posts formed at adjacent positions on the conductor lines of the first and second independent electronic circuits without being separated from each other.

2. The electronic circuit according to claim 1, characterized in that, At least one of the plurality of independent electronic circuits is a circuit for suppressing electromagnetic noise of the same frequency.

3. The electronic circuit according to claim 2, characterized in that, The conductor lines of each of the plurality of independent electronic circuits are lines whose ends, different from the open ends of the conductor lines, are connected to the conductor posts.

4. The electronic circuit according to claim 3, characterized in that, The conductor line is a line that extends continuously or intermittently from one end toward the other in the same direction of rotation.

5. A circuit board, characterized in that, It is equipped with the electronic circuitry described in any one of claims 1 to 4.

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