Printed wiring board

Abstract

Provided is a printed wiring board with which it is possible to reduce the wire width while maintaining a required electric resistance value of a power supply path.　The printed wiring board comprises a power supply layer which includes a conductor part (15) having a first end part (15a) and a second end part (15b) opposite each other on a power supply path, a first conductor connection part (131) protruding from the first end part (15a) in a direction away from the conductor part (15) on the path, and a second conductor connection part (132) protruding from the second end part (15b) in a direction away from the conductor part (15) on the path. The conductor part (15) comprises a first region (151) sandwiched between the first end part (15a) and the second end part (15b), and a second region (152) and a third region (153) which are positioned opposite each other on both sides of the first region (151). The second region (152) and the third region (153) have the same shape obtained by dividing a circle or a regular polygon with an even number of 16 or more vertices in half so as to pass through the center thereof.

Description

printed wiring board

[0001] The present disclosure relates to printed wiring boards.

[0002] In a printed wiring board, a technique is known in which the width of the wiring between terminals is widened in the power supply path that supplies power in order to ensure current capacity against voltage drops due to electrical resistance and fluctuations in load, etc. Also, Japanese Patent Application Laid-Open No. 2004-39686 proposes a power supply solid shape that surrounds the power supply terminal to reduce impedance.

[0003] One aspect of the present disclosure is a printed wiring board comprising: a power supply layer having a conductor portion located on a power supply path and having a first end and a second end facing each other; a first conductor connection portion connected to the first end on the path and protruding from the first end in a direction opposite to the conductor portion; and a second conductor connection portion connected to the second end on the path and protruding from the second end in a direction opposite to the conductor portion, wherein the conductor portion comprises a first region sandwiched between the first end and the second end, and a second region and a third region located opposite each other and in contact with portions of the first region that are not in contact with the first conductor connection portion and the second conductor connection portion, and the second region and the third region each have the same shape obtained by dividing a regular polygon or a circle having an even number of angles (16 or more) in half through a line passing through the center of the regular polygon or the circle.

[0004] 1 is a schematic diagram showing one embodiment of a power supply path; FIG. 1 is a schematic diagram showing another embodiment of the power supply path; FIG. 2 is an enlarged plan view showing a power supply path between a first conductor connection portion and a second conductor connection portion; FIG. 3 is a table showing the results of a numerical simulation related to the shape of the conductor portion; FIG. 4 is a table showing the results of a numerical simulation related to the shape of the conductor portion; FIG. 5 is a diagram showing the current direction and current density distribution of the conductor portion obtained by numerical simulation; FIG. 6 is a diagram showing the current direction and current density distribution of the conductor portion obtained by numerical simulation; FIG. 7 is a diagram showing another example of a power supply path; FIG. 8 is an explanatory diagram of a power supply path of a second embodiment; FIG. 9 is a table showing the results of a numerical simulation of the power supply path of the second embodiment; FIG. 10 is a diagram showing the current direction and current density distribution of the conductor portion of the second embodiment obtained by numerical simulation; FIG. 11 is a diagram showing the current direction and current density distribution of the conductor portion of the second embodiment obtained by numerical simulation; FIG. 12 is a diagram showing the shape of a conductor portion of a comparative example of the second embodiment; FIG. 13 is a diagram showing the results of a numerical simulation of the current density distribution related to a conductor portion of a reference shape; FIG. 14 is a diagram showing the results of a numerical simulation of the current density distribution related to the shape of the conductor portion of the comparative example; FIG. 15 is an explanatory diagram of a power supply path between a first conductor connection portion and a second conductor connection portion in a printed wiring board of a third embodiment. 10 is a diagram showing the results of a numerical simulation relating to the resistance value of a conductor portion according to the shape between a first conductor connecting portion and a second conductor connecting portion in a printed wiring board of a third embodiment. FIG. 11 is a diagram showing the current direction and current density distribution of a conductor portion of a third embodiment obtained by numerical simulation. FIG. 12 is a diagram showing the current direction and current density distribution of a conductor portion of a reference shape according to a third embodiment obtained by numerical simulation. FIG. 13 is a diagram explaining a power supply path between a first conductor connecting portion and a second conductor connecting portion in a printed wiring board of a fourth embodiment. FIG. 14 is a diagram showing the results of a numerical simulation relating to the power supply path between a first conductor connecting portion and a second conductor connecting portion in a printed wiring board of a fourth embodiment. FIG. 15 is a diagram showing the current direction and current density distribution of a conductor portion of a fourth embodiment obtained by numerical simulation.10A and 10B are diagrams showing the current direction and current density distribution of the conductor portion of the fourth embodiment obtained by numerical simulation, and the current direction and current density distribution of the conductor portion of the reference shape according to the fourth embodiment obtained by numerical simulation.

[0005] The following describes an embodiment with reference to the drawings. Fig. 1A is a schematic plan view of a power supply path connecting a first IC 11, which is a power supply source, and a second IC 12, which receives power, on the same layer as the ICs. Fig. 1B is a schematic cross-sectional view of a printed wiring board 1 on which the first IC 11 and the second IC 12 are mounted, with the power supply path located on the same layer as the ICs.

[0006] 1A, the printed wiring board 1 has a first IC 11 that serves as a power supply source and a second IC 12 that receives the power supply. There may be multiple second ICs 12. The voltages received by the multiple second ICs 12 may be different from each other. The first IC 11 can supply power such as one or more voltages (constant voltages) or currents (constant currents) to the second ICs 12.

[0007] The first IC 11 has an output terminal 111, which is connected to a first conductor connection portion 131. The second IC 12 has an input terminal 121, which is connected to a second conductor connection portion 132. The first conductor connection portion 131 and the second conductor connection portion 132 are connected to each other by a power supply solid, which is a planar conductor portion 15. The power supply path runs from the output terminal 111 to the first conductor connection portion 131, the conductor portion 15, the second conductor connection portion 132, and the input terminal 121 in this order.

[0008] The first IC 11 and / or the second IC 12 may be located on a conductor layer of the printed wiring board 1 different from the power supply layer 10 including the conductor portion 15. In this case, the output terminal 111 and the first conductor connecting portion 131, and the input terminal 121 and the second conductor connecting portion 132 may be connected via a through conductor that penetrates the insulating layer between the conductor portion 15 and the first IC 11 and / or the second IC 12, respectively. If the insulating layer 20 is, for example, a solder resist, the first conductor connecting portion 131 exposed in an opening in the solder resist and the output terminal 111 are connected by solder S. Furthermore, the second conductor connecting portion 132 exposed in an opening in the solder resist and the input terminal 121 are connected by solder S. The power supply layer 10 may be located on an inner layer of the printed wiring board 1 having a multilayer structure. The sizes of the first IC 11, the second IC 12, and the conductor portion 15 shown in FIGS. 1A and 1B are for illustrative purposes only and may not reflect the actual size ratios.

[0009] [First Embodiment] FIG. 2 is an enlarged plan view showing the power supply layer 10, which is a power supply path between the first conductor connection portion 131 and the second conductor connection portion 132 in the first embodiment. The direction from the first conductor connection portion 131 to the second connection portion is the X direction, and the Y direction is defined perpendicular to the X direction. The first conductor connection portion 131 and the second conductor connection portion 132 may both be squares with sides of length C. At least the first end portion 15a, which is the connection portion between the first conductor connection portion 131 and the conductor portion 15, and the second end portion 15b, which is the connection portion between the second conductor connection portion 132 and the conductor portion 15, are parallel straight lines extending in the Y direction in a plan view and face each other. The first conductor connection portion 131 protrudes from the first end portion 15a in the direction opposite the conductor portion 15, i.e., in the −X direction. The second conductor connection portion 132 protrudes from the second end portion 15b in the direction opposite the conductor portion 15, i.e., in the +X direction.

[0010] The conductor portion 15 includes a first region 151, which is rectangular in plan view and extends in the X direction and is sandwiched between the first end portion 15a and the second end portion 15b, and a second region 152 and a third region 153, each connected to the first region 151. The second region 152 and the third region 153 are located on either side of the first region 151 in the ±Y direction, perpendicular to the extension direction of the first region 151. That is, the second region 152 and the third region 153 are located opposite each other, contacting portions of the first region 151 that are not in contact with either the first conductor connection portion 131 or the second conductor connection portion 132. The second region 152 and the third region 153 each have a shape obtained by dividing a regular hexadecagon into two identical halves in plan view. This shape will be referred to as a semi-regular hexadecagon hereinafter. In this embodiment, the dividing line passes through the center of the regular hexadecagon and connects the two diagonal vertices. The dividing lines of the regular hexadecagon of the second region 152 and the third region 153 each contact the first region 151. The length of the first region 151 in the Y direction, which is perpendicular to the extension direction of the first region 151, i.e., along the width direction, is equal to the length C of one side of the first conductor connection portion 131 and the second conductor connection portion 132. This length in the Y direction will hereinafter be referred to as the width. The length L of the first region 151 in the X direction, i.e., the distance between the first end 15a and the second end 15b, is equal to the length of the dividing lines of the second region 152 and the third region 153. In other words, the semi-regular hexadecagon is inscribed in a circle of radius A, as shown by the dotted line. The radius A corresponds to ½ of the length L of the first region 151.

[0011] Next, a description will be given of a suitable shape of the conductor portion 15. As described above, the conductor portion 15 needs to have low electrical resistance in order to reduce voltage drop and heat generation on the power supply path. Since the electrical resistance of an electrical wiring is proportional to its length and inversely proportional to its cross-sectional area, the cross-sectional area, particularly the width of the planar wiring, is set to be wider than the widths of the first conductor connection portion 131 and the second conductor connection portion 132.

[0012] However, in areas where the wiring width suddenly expands or contracts, especially in areas where the width is discontinuous, the current does not immediately diffuse or converge even if the width of the conductor 15 is large. Therefore, in conventional large rectangular conductors, there are areas where almost no current flows. Such areas do not contribute much to reducing electrical resistance compared to the increase in area.

[0013] The printed wiring board 1 of this embodiment has a conductor portion 15 with a shape in which portions that contribute little to reducing electrical resistance have been removed. That is, the conductor portion 15 has a rectangular shape with the corners appropriately removed. This reduces the size of the conductor portion 15 while keeping the increase in electrical resistance within a range that does not cause problems.

[0014] 3A and 3B are graphs showing the results of a numerical simulation of the conductor shape. In this numerical simulation, the electrical resistance of the conductor 15 was calculated based on the voltage drop between the first conductor connection 131 and the second conductor connection 132, each measuring 4 mm x 4 mm x 0.03556 mm, when a current of 1 A flows at an input voltage of 1 V to the first conductor connection 131. The insulating layer on which the conductor 15, which is the power supply solid, is formed has a thickness of 30 μm, a relative dielectric constant of 4.6, and a dielectric dissipation factor of 0.014, corresponding to R-1766 manufactured by Panasonic (registered trademark). The conductor 15 is formed on this insulating layer using copper (electrical conductivity ρ = 5.959E+07 S / m) with a thickness of 35.56 μm. The upper surface of the conductor 15 is covered with a 30 μm thick solder resist (relative dielectric constant 4.2, dielectric dissipation factor 0.021). The resistance value of the conductor portion 15 under the above conditions was calculated using Cadence Power DC ver. 17 from Cadence Design Systems, Inc. (Cadence; registered trademark).

[0015] In FIG. 3A , as an example of a "rectangle," the conductor portion 15 has a conventional rectangular shape. The resistance value is calculated for a case where the length L of the conductor portion 15 is 2A and the width W of the conductor portion 15 is 250 mm, and this resistance value is shown as the reference resistance value. The length L is the distance between the first conductor connection portion 131 and the second conductor connection portion 132. The width W is the length perpendicular to the length of the conductor portion 15. The upper limit of the allowable resistance value is set to 105% of the reference resistance value, i.e., a change rate of 5%. The change rate of 5% or less in the resistance value comes from the fact that in connection reliability evaluation of via conductors, a resistance value of more than 10% of the initial value after environmental reliability testing such as temperature cycling is generally deemed to be a failure. In more stringent cases, a change rate of more than 5% may be used. This concept of connection reliability evaluation is applied to the examination of electrical characteristics, and the stricter standard is used for judgment. A non-failure value, i.e., 5% or less, is adopted as the allowable change amount in the power supply path of this embodiment. The width of the first region 151, that is, the length in the direction perpendicular to the length of the conductor portion 15, is 4 mm, the same as that of the output terminal 111 and the input terminal 121.

[0016] Each row shows the results when the distance between the first conductor connection portion 131 and the second conductor connection portion 132 (in other words, the length A, which is half the length L at which the first region 151, the second region 152, and the third region 153 are in contact) is changed to three different values: 40, 50, and 60 mm. The "Semicircular" column shows the resistance values ​​obtained as a result of a numerical simulation when the second region 152 and the third region 153 are semicircular, divided into a circle with a radius of the length A and passing through the center of the circle. The "Semi-elliptical" column shows the resistance values ​​obtained as a result of a numerical simulation when the second region 152 and the third region 153 are semi-elliptical, divided into a circle with a major axis length of the length L and a minor axis length of 2 times 3 / 4 (1.5 times) the length A, i.e., 0.75 times the major axis length, and passing through the major axis of the ellipse.

[0017] The results showed that the resistance value when the second region 152 and the third region 153 were semicircular was within 5% of the reference resistance value, regardless of the radius A or the length L. The results showed that the resistance value when the second region 152 and the third region 153 were semi-elliptical was above the allowable resistance value, regardless of the radius A or the length L.

[0018] 3B shows the results of a numerical simulation in which the resistance values ​​are calculated when the second region 152 and the third region 153 have a shape obtained by dividing a regular polygon inscribed in the semicircular shape in half, where the radius A is 40 mm.

[0019] The more corners the inscribed regular polygon has, the smaller the reduction in area compared to a semicircular shape becomes, and the smaller the resistance value becomes. It has been shown that when the number of corners is 16, the resistance value falls below the allowable resistance value. When the number of corners is greater than 16, the shape approaches a semicircle even more, and the resistance value approaches that of a semicircle.

[0020] 4A shows the current direction and current density distribution of the conductor portion obtained by numerical simulation when the second region 152 and the third region 153 are semihexagonal. FIG. 4B shows the current direction and current density distribution of the conductor portion obtained by numerical simulation when the second region 152 and the third region 153 are semicircular. In both cases, the current is shown diffusing from the first conductor connection portion 131 along an arc and converging to the second conductor connection portion 132. Furthermore, the overall current density tends to be high around the first region 151, which flows directly from the output terminal 111 to the input terminal 121, and relatively low near the edges of the second region 152 and the third region 153. Therefore, if the second region 152 and the third region 153 are close to a circle, the conductor portion 15 is less likely to obstruct the current, thereby suppressing an increase in resistance.

[0021] Furthermore, the first conductor connecting portion 131 and the second conductor connecting portion 132 are positioned so as to contact the first end 15a and the second end 15b, which are the boundaries of the conductor portion 15, respectively, and protrude outward. Therefore, current flows out in a substantially constant direction from one side of the first conductor connecting portion 131 to the conductor portion 15, and flows in a substantially constant direction to one side of the second conductor connecting portion 132. That is, current does not flow out through the three sides of the first conductor connecting portion 131 other than the boundary of the conductor portion 15, nor does current flow in through the three sides of the second conductor connecting portion 132 other than the boundary of the conductor portion 15. In other words, the current density near the first region 151 can be increased, while the conductor area can be substantially reduced by locally controlling the current density to be small.

[0022] FIG. 5 is a diagram showing another example of a power supply path.

[0023] In the example of FIG. 5 , the first conductor connecting portion 131a and the second conductor connecting portion 132a are enlarged. Their shapes are modified from the square shape of the first conductor connecting portion 131 and the second conductor connecting portion 132 in plan view. Like the rectangular first conductor connecting portion 131 and the second conductor connecting portion 132, the connection portions of the first conductor connecting portion 131a and the second conductor connecting portion 132a with the first end 15a and the second end 15b of the first region 151 are straight lines each having a length C in plan view. The range of length C / 2 from the connection portions of the first conductor connecting portion 131a and the second conductor connecting portion 132a is rectangular in plan view, with the width maintained at length C. In the first conductor connecting portion 131a, a first curved portion 131b, which is a semicircular outline portion in plan view with a diameter C of length C, connects to the rectangular portion on the opposite side of the first region 151. In the second conductor connection portion 132a, a second curved portion 132b, which is a semicircular outline portion in plan view with a diameter of length C relative to the rectangular portion in plan view, is connected to the opposite side of the rectangular portion from the first region 151.

[0024] In this way, the first conductor connection portion 131a and the second conductor connection portion 132a do not have to be rectangular, particularly square, as long as the connection portion with the first region 151 is linear in a plan view. The first conductor connection portion 131a and the second conductor connection portion 132a may have a shape corresponding to the shape of the output terminal 111 or the input terminal 121, for example.

[0025] As described above, the printed wiring board 1 of this embodiment includes a power supply layer 10 having a conductor portion 15, a first conductor connecting portion 131, and a second conductor connecting portion 132. The conductor portion 15 is located on a power supply path and has a first end 15a and a second end 15b that face each other. The first conductor connecting portion 131 is connected to the first end 15a on the path and protrudes from the first end 15a in a direction opposite the conductor portion 15. The second conductor connecting portion 132 is connected to the second end 15b on the path and protrudes from the second end 15b in a direction opposite the conductor portion 15. The conductor portion 15 includes a first region 151 sandwiched between the first end 15a and the second end 15b, and a second region 152 and a third region 153 that face each other and contact portions of the first region 151 that do not contact the first conductor connecting portion 131 and the second conductor connecting portion 132. The second region 152 and the third region 153 each have the same shape, which is a regular polygon or a circle having an even number of angles (16 or more) divided in half at the center of the regular polygon or the circle. By using such a shape for the conductor 15, the printed wiring board 1 can efficiently reduce the area of ​​the conductor 15 from the conventional rectangular shape while maintaining the electrical resistance of the conductor 15 at the same level as that of a conventional rectangular shape. The reduced size of the conductor 15 can be used for other wiring, etc.

[0026] Furthermore, the first end 15a and the second end 15b are parallel to each other and linear, and have the same length. Therefore, in the printed wiring board 1, current can flow efficiently with uniform current distribution from the first conductor connection portion 131 to the second conductor connection portion 132 in a linear manner. Therefore, this printed wiring board 1 can effectively reduce increases in resistance. The length of the first end 15a can be defined as the length of the portion where the first conductor connection portion 131 contacts the conductor portion 15. The length of the second end 15b can be defined as the length of the portion where the second conductor connection portion 132 contacts the conductor portion 15.

[0027] The second region 152 and the third region 153 each have a shape obtained by dividing a regular polygon, and the regular polygon is sized to be inscribed in a circle whose diameter is the distance between the first end 15 a and the second end 15 b. This shape enables the printed wiring board 1 to appropriately control the distribution of current density and maintain the electrical resistance of a conventional power supply solid shape.

[0028] Furthermore, first conductor connecting portion 131 has first curved portion 131b located on the opposite side of first end portion 15a from conductor portion 15. Second conductor connecting portion 132 has second curved portion 132b located on the opposite side of second end portion 15b from conductor portion 15. With such a shape, printed wiring board 1 can be suitably connected in accordance with the shapes of output terminal 111 and input terminal 121, and can avoid unnecessary increase in area.

[0029] Furthermore, the first conductor connection portion 131 and the second conductor connection portion 132 may face each other in the X direction perpendicular to the Y direction along the first end portion 15a. This allows the first conductor connection portion 131 and the second conductor connection portion 132 to be connected by the conductor portion 15 at the shortest distance. Furthermore, the current distribution is approximately symmetrical between the second region 152 and the third region 153, and the conductor portion 15 can reduce variations in current density.

[0030] Furthermore, the printed wiring board 1 may have the same length in the Y direction along the first end 15a of the first conductor connecting portion 131 as the same length in the Y direction along the second end 15b of the second conductor connecting portion 132. Here, the length of the first conductor connecting portion 131 along the first end 15a may be equal to the length of connection of the first conductor connecting portion 131 with the first end 15a. The length of the second conductor connecting portion 132 along the second end 15b may be equal to the length of connection of the second conductor connecting portion 132 with the second end 15b. Such first conductor connecting portion 131 and second conductor connecting portion 132 tend to balance the inflow and outflow of current. Therefore, the printed wiring board 1 can reduce an increase in resistance and also reduce an increase in the area of ​​the conductor portion 15.

[0031] Second Embodiment A power supply path according to a second embodiment will now be described. FIG. 6A is a diagram illustrating the power supply path according to the second embodiment. FIG. 6A is an enlarged plan view illustrating the power supply layer 10, which is the power supply path between the first conductor connection portion 131 and the second conductor connection portion 1321. The sizes of the first conductor connection portion 131 and the second conductor connection portion 1321 may be different from each other. For example, the second conductor connection portion 1321 may be a square having a side length longer than that of the first conductor connection portion 131. As an example, the side length of the second conductor connection portion 1321 may be five times the side length C of the first conductor connection portion 131 (=4 mm), i.e., 20 mm. The lengths of the first end portion 15a and the second end portion 15b are equal to the side length of the second conductor connection portion 1321. The side on the −X side of the second conductor connection portion 1321 may be connected to the entire second end portion 15b. One side of the first conductor connection portion 131 on the +X side is connected to a part of the first end portion 15a. The first conductor connection portion 131 and the second conductor connection portion 1321 face each other in the X direction perpendicular to the Y direction along the first end portion 15a. For example, one side of the first conductor connection portion 131 may be connected to the first end portion 15a at the center of the first end portion 15a in the Y direction, that is, between points that are a length 2C = 8 mm from both ends of the first end portion 15a.

[0032] 6B is a table showing the results of a numerical simulation of the shape of the conductor portion shown in FIG. 6A and a comparison example. As described above, the width of the first region 1511 in the Y direction is 20 mm, and the second conductor connection portion 1321 is a square with a side length of 20 mm. The first conductor connection portion 131, which is 4 mm wide, is connected to the center of the first end portion 15a in the Y direction. Parameters not specified are the same as those in the first embodiment.

[0033] The two left columns show the reference resistance value when the second region 152 and the third region 153 have a standard rectangular shape with a side length of A extending from the first region 1511 in the ±Y direction, and the allowable resistance value which is 105% of the reference resistance value.

[0034] When the second region 152 and the third region 153 connected to the first region 1511, which has a vertical width of 20 mm, are each semicircular with a radius A as shown by the dotted line, the width W of the conductor portion 15 in the Y direction is 2A + 20. The resistance value in this case is smaller than the allowable resistance value. When the second region 152 and the third region 153 are each semihexagonal as shown by the solid line, the resistance value is also smaller than the allowable resistance value.

[0035] 7A and 7B are diagrams showing the current direction and current density distribution of the conductor portion of the second embodiment obtained by numerical simulation. FIG. 7A shows the case where the second region 152 and the third region 153 are semihexagonal, and FIG. 7B shows the case where the second region 152 and the third region 153 are semicircular. Conductor portions of these shapes have smaller variations in overall current density compared to other regions. Meanwhile, as described above, the increase in resistance is small, so current flows efficiently through the second region 152 and the third region 153. Since the area of ​​a semiregular polygon inscribed in a semicircle is smaller than that of a semicircle, the area of ​​the second region 152 and the third region 153 can be reduced if the semiregular polygon is a semihexagon or larger than a semicircle.

[0036] FIG. 8 shows the shape of a conductor portion 15r of a comparative example. The width W of the first region 151r is 4 mm in the left half of the conductor portion 15r and expands radially to 20 mm in the right half. A second region 152r and a third region 153r, each having a sectorial shape with a radius A, are connected to the first region 151r. The second conductor connection portion 1321 is connected to the conductor portion 15r at a position where the vertical width of the conductor portion 15r is 20 mm. That is, the width W of the conductor portion 15r is 2A+4 mm, and the length L is shorter than the diameter 2A. In the example of FIG. 8, the resistance value exceeds the allowable resistance value, as shown in FIG. 6B.

[0037] FIG. 9A is a diagram showing the results of a numerical simulation of the current density distribution in the conductor portion 15 having the reference shape.

[0038] 9A has a rectangular shape as described above. In this case, most of the current flows from the first conductor connection portion 131 to the second conductor connection portion 1321 in a straight line or an arc. As a result, the current density near the corners of the second region 152 and the third region 153 is smaller than that in the line connecting the first conductor connection portion 131 and the second conductor connection portion 1321 in an arc. While such a region has a large effect on increasing the area, it contributes little to reducing the resistance value.

[0039] 9B is a diagram showing the results of a numerical simulation of the current density distribution according to the shape of the conductor portion 15. The current density distribution shown in FIG. 9B corresponds to the shape of the conductor portion 15r of the comparative example. The current density distribution in this case is similar to that in FIG. 9A. However, in this case, current is concentrated near the corners where the second region 152r and the third region 153r meet the second conductor connection portion 1321. Such current concentration areas lead to an increase in resistance value.

[0040] According to the printed wiring board 1 of the second embodiment, the conductor portion 15 may have a length different from that of the first end portion 15 a of the first conductor connecting portion 131 in the direction along the second end portion 15 b of the second conductor connecting portion 1321. Even if the sizes of the conductor connecting portions connected by the conductor portion 15 are different, the shape disclosed herein can efficiently reduce the size and reduce an increase in resistance value, as needed.

[0041] Furthermore, the first conductor connection portion 131 and the second conductor connection portion 1321 may be opposite to each other even if they have different sizes. That is, in the Y direction along the first end portion 15 a and the second end portion 15 b, the first conductor connection portion 131 may be located within a range in the Y direction in which the longer second conductor connection portion 1321 is located. This makes the current density distribution approximately symmetrical between the second region 152 and the third region 153, and the conductor portion 15 can reduce bias in current density and allow current to flow with low resistance.

[0042] 10A is a diagram illustrating a power supply path between a first conductor connection portion 131 and a second conductor connection portion 132 in a printed wiring board 1 according to the third embodiment.

[0043] In this power supply path, the first conductor connection portion 131 and the second conductor connection portion 132 are located at different positions in the Y direction along the first end portion 15 a and the second end portion 15 b. In other words, the first conductor connection portion 131 and the second conductor connection portion 132 do not have to face each other in the Y direction.

[0044] 10A , the first conductor connection portion 131 may be located at the end of the first end portion 15a on the +Y side where it contacts the second region 152, and the second conductor connection portion 132 may be located at the end of the second end portion 15b on the −Y side where it contacts the third region 153. In other words, the widths of the first end portion 15a and the second end portion 15b correspond to the offset between the first conductor connection portion 131 and the second conductor connection portion 132 in the Y direction.

[0045] 10B is a table showing the results of a numerical simulation of the resistance value of the conductor portion 15 according to the shapes of the first conductor connection portion 131 and the second conductor connection portion 132. The two left columns show the reference resistance value and the allowable resistance value when the conductor portion 15 is a rectangular region with a width W in the Y direction of 250 mm. The two right columns show the resistance values ​​when the width W of the first region 151 is 80 mm and the second region 152 and the third region 153 are semicircular with a radius A, and when they are semiregular hexagons inscribed in a semicircle with a radius A. These resistance values ​​are almost the same and smaller than the allowable resistance value.

[0046] 11A, 11B, and 12 are diagrams showing the current direction and current density distribution in the third embodiment obtained by numerical simulation. FIG. 11A shows the current density distribution when the second region 152 and the third region 153 are semihexagonal. FIG. 11B shows the current density distribution when the second region 152 and the third region 153 are semicircular. In either case, the bias in the current density distribution within the conductor portion 15 is small, i.e., the increase in resistance value is reduced, and the increase in unnecessary area is also reduced. In other words, the semihexagonal second region 152 and the third region 153 have a smaller area than the semicircular second region 152 and the third region 153, while achieving a similar resistance value.

[0047] 12 shows the current direction and current density distribution of the conductor part of the reference shape according to the third embodiment, and similar to the results shown in Fig. 9A, there are areas where the current density is relatively low along the edge of the conductor part 15. In other words, the conductor part 15 has the disadvantage of increasing the area, compared to the effect of reducing the resistance value.

[0048] In this way, in the printed wiring board 1, the first conductor connecting portion 131 and the second conductor connecting portion 132 do not need to face each other in the X direction, which is perpendicular to the Y direction along the first end 15a. Depending on the positional relationship of the connected electronic components, the first conductor connecting portion 131 and the second conductor connecting portion 132 may not face each other. In such a case, the first region 1512 has the first end 15a and the second end 15b in a range that includes the first conductor connecting portion 131 and the second conductor connecting portion 132 in the Y direction. By connecting the second region 152 and the third region 153, which are semiregular polygons with a semiregular hexadecagon or greater, to this first region 1512, it is possible to achieve both a reduction in the increase in area and a reduction in the increase in electrical resistance.

[0049] 13A is a diagram illustrating a power supply path between a first conductor connection portion 131 and a second conductor connection portion 1321 in a printed wiring board 1 according to the fourth embodiment.

[0050] 13A , in this power supply path, the first conductor connection portion 131 and the second conductor connection portion 1321 have different sizes, and the first conductor connection portion 131 and the second conductor connection portion 1321 do not face each other in the Y direction. That is, in this power supply path of the fourth embodiment, the pair of the first conductor connection portion and the second conductor connection portion 1321 in the second embodiment has the same positional relationship as the first conductor connection portion and the second conductor connection portion 132 in the third embodiment. The other shapes and positional relationships are the same as those of the other embodiments. The dotted lines indicate a case where the shapes of the second region 152 and the third region 153 are semicircular. The solid lines indicate a case where the shapes of the second region 152 and the third region 153 are semiregular hexadecagons inscribed in the semicircles.

[0051] 13B is a diagram showing the results of a numerical simulation of the power supply path between the first conductor connection portion 131 and the second conductor connection portion 1321 in the printed wiring board 1 of the fourth embodiment. As shown in FIG. 13B , the resistance of the conductor portion 15 is smaller than the allowable resistance value when the second region 152 and the third region 153 are semicircular or semihexagonal. That is, when the second region 152 and the third region 153 are semihexagonal, the area can be reduced compared to a semicircular shape, while the resistance can be kept below the allowable resistance value.

[0052] 14A, 14B, and 15 are diagrams showing the current direction and current density distribution in the fourth embodiment obtained by numerical simulation. Whether the second region 152 and the third region 153 shown in FIG. 14A are semihexagonal or the second region 152 and the third region 153 shown in FIG. 14B are semicircular, there is no significant bias in the current density distribution. Therefore, it can be seen that the semihexagonal second region 152 and the third region 153 can reduce the increase in resistance and reduce the increase in area compared to the semicircular shapes.

[0053] 15 shows the current direction and current density distribution of the conductor part of the reference shape according to the fourth embodiment, where the current density is smaller near the edge of the conductor part 15 than in other parts. That is, it can be seen that the shape of the conductor part 15 is large in size compared to the reduction in resistance value.

[0054] In this way, in the printed wiring board 1, the length in the Y direction of the first conductor connecting portion 131 and the length in the Y direction of the second conductor connecting portion 1321 may be different from each other, and the first conductor connecting portion 131 and the second conductor connecting portion 1321 may not face each other in the X direction. Under conditions according to the position and size of the electronic component, the printed wiring board 1 can flexibly reduce the size of the conductor portion 15 and reduce an increase in the resistance value of the current path.

[0055] The above embodiment is merely an example, and various modifications are possible. The power supply layer 10 may be located on an inner layer of the printed wiring board 1 having a multi-layer structure. The first IC 11 connected to the power supply layer 10 may be built into or mounted on the wiring board 1. The first IC 11 may be connected to the first conductor connection portion 131 and the second conductor connection portion 132 by wiring via a through conductor in an insulating layer. Additionally, power may be supplied externally without using a power supply IC. By locating the power supply layer 10 on an inner layer of the printed wiring board 1, it becomes easy to arrange, for example, a circular power supply layer 10 without any barriers caused by components mounted on the surface of the printed wiring board 1.

[0056] For example, the lengths of the first end 15 a and the second end 15 b may be slightly different, in which case the first region 151 may be determined based on the longer of the first end 15 a and the second end 15 b.

[0057] Furthermore, the shapes of the first conductor connection portion 131 and the second conductor connection portion 132 do not have to be the same. The first conductor connection portion 131 and the second conductor connection portion 132 may have different shapes depending on the shapes of the output terminal 111 and the input terminal 121, or regardless of these.

[0058] In the above embodiment, the shapes of the first conductor connection portion 131 and the second conductor connection portion 132 are described as a combination of a rectangular shape and a semicircular shape in plan view, but this is not limited to this. As long as the portions in contact with the first end portion 15a and the second end portion 15b are straight lines, they may have any suitable shape. Furthermore, the semicircular portions may instead have a polygonal shape, etc. Furthermore, in this case, the polygonal shape does not have to be a regular polygon.

[0059] In addition, in the above embodiment, the power supply layer 10 is an inner layer of the multi-layer substrate, but this is not limited to this. The power supply layer 10 may be an outer layer. In addition, the specific details such as the specific configuration, structure, and size shown in the above embodiment can be changed as appropriate without departing from the spirit of the present disclosure.

[0060] The present disclosure can be used in printed wiring boards.

[0061] REFERENCE SIGNS LIST 1 printed wiring board 10 power supply layer 11 first IC 111 output terminal 12 second IC 121 input terminal 131, 131a first conductor connection portion 131b first curved portion 132, 132a, 1321 second conductor connection portion 132b second curved portion 15, 15r conductor portion 15a first end portion 15b second end portion 151, 1511, 1512, 151r first region 152, 1521, 152r second region 153, 1531, 153r third region

Claims

1. a conductor portion located on a power supply path and having a first end and a second end opposite to each other; a first conductor connection portion connected to the first end portion on the path and protruding from the first end portion in a direction opposite to the conductor portion; a second conductor connection portion connected to the second end portion on the path and protruding from the second end portion in a direction opposite to the conductor portion; a power plane having the conductor portion includes a first region sandwiched between the first end portion and the second end portion, and a second region and a third region positioned opposite each other and in contact with a portion of the first region that is not in contact with the first conductor connecting portion and the second conductor connecting portion, The second region and the third region each have the same shape obtained by dividing a regular polygon or a circle having an even number of angles of 16 or more into halves along a line passing through the center of the regular polygon or the circle. Printed wiring board.

2. The first end and the second end are linear and parallel to each other and have the same length. The printed wiring board according to claim 1 .

3. the second region and the third region each have a shape obtained by dividing the regular polygon, The regular polygon has a size such that it is inscribed in a circle whose diameter is the distance between the first end and the second end. The printed wiring board according to claim 1.

4. the first conductor connection portion has a first curved portion located on the opposite side of the conductor portion from the first end portion, and the second conductor connection portion has a second curved portion located on the opposite side of the conductor portion from the second end portion. The printed wiring board according to claim 1.

5. The power supply layer is located in an inner layer of the printed wiring board having a multilayer structure. The printed wiring board according to claim 1.

6. 2. The printed wiring board according to claim 1, wherein the length of the first conductor connecting portion in the direction along the first end portion is equal to the length of the second conductor connecting portion in the direction along the second end portion.

7. The printed wiring board according to claim 1 , wherein the length of the first conductor connecting portion in the direction along the first end portion is different from the length of the second conductor connecting portion in the direction along the second end portion.

8. 2. The printed wiring board according to claim 1, wherein the first conductor connecting portion and the second conductor connecting portion face each other in a direction perpendicular to a direction along the first end portion.

9. 2. The printed wiring board according to claim 1, wherein the first conductor connecting portion and the second conductor connecting portion do not face each other in a direction perpendicular to a direction along the first end portion.