JP2016063094A - Power supply circuit and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a wide band of high frequency noise to be removed.SOLUTION: A power supply circuit using a multilayer printed circuit board includes: a first layer on which a power supply line 105 is formed; a second layer in which a land 106 corresponding to a size of the power supply line 105 is formed right below the power supply line 105; and a third layer in which a ground surface 107 is formed right below the land 106, the land 106 being connected to the ground surface 107 through a via 108. The power supply circuit includes, on the ground surface 107 at a position right below the power supply line 105, a plurality of com-like conductors 110 corresponding to a size of the power supply line 105 formed along a length direction L of the power supply line 105 with a predetermined slit width s, so as to have predetermined filter characteristics.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power supply circuit and electronic equipment for removing power supply noise.

  As a countermeasure against high-frequency noise radiated from a power supply line mounted on a printed circuit board (PCB), for example, there is a technique for removing high-frequency noise by surface-mounting a chip-shaped bypass capacitor or a ferrite bead on an IC power supply terminal. In this technique, several capacitors with different constants are mounted in accordance with the frequency to be removed. However, the actual line impedance and load impedance are different, and it is difficult to remove predetermined high-frequency noise when selecting constants at the time of design.

  In addition, when the IC is a bump terminal, a bypass capacitor or a ferrite bead is mounted at a location away from the power supply terminal, and an inductance component increases, so that several types of capacitors are used. In this case, the mounting area of the capacitor on the printed circuit board increases, and the amount of high frequency noise removal becomes smaller than expected.

  For this reason, there is a structure in which a capacitance and an inductance component are provided inside a multilayer printed board. For example, there is a printed circuit board technology using a mushroom type EBG (Electromagnetic Band Gap) in which small pieces of conductor are periodically arranged in an inner layer. In addition, there is a band rejection filter technique in which a plurality of through holes are provided on both sides of a microstrip line. Further, there is a technique in which GND vias connected to the GND plane are provided radially with a power supply via connected to the power plane of the multilayer printed circuit board as a center, and a capacitance is provided between the vias. There is also a technique for forming a low-pass filter by forming a power line and GND in a linear shape, increasing the inductance by forming the power line in a linear meander pattern (see, for example, Patent Documents 1 to 4 below).

JP 2010-10183 A JP 2001-111303 A JP-A-8-148368 JP-A-9-54788

  However, the conventional technology cannot remove high-frequency noise of a predetermined frequency (for example, several hundred MHz to several GHz) without increasing the size of the printed circuit board. For example, in the structure in which the power supply line is connected to the GND via the via, the via is connected in parallel to the GND surface having a large area, so that the inductance component becomes small and broadband high frequency noise cannot be removed. In addition, in a structure in which GND is formed in a linear shape to have an inductance component, good GND characteristics cannot be obtained.

  In one aspect, an object of the present invention is to remove broadband high-frequency noise.

  In one proposal, in a power supply circuit that removes power supply noise using a multilayer printed circuit board, a first layer in which a power supply line is formed, and a land corresponding to the size of the power supply line at a position immediately below the power supply line. And a third layer in which a ground plane is formed below the land, and the land is connected to the ground plane through a via, and the power source of the ground plane is A plurality of comb-like conductors formed with a predetermined slit width along the length direction of the power supply line corresponding to the size of the power supply line at a position directly below the line; It is a requirement to have the following filter characteristics.

  According to one embodiment, broadband high frequency noise can be removed.

FIG. 1 is a side view illustrating a configuration example of a power supply circuit according to the embodiment. FIG. 2 is a perspective view illustrating a configuration example of each layer of the printed circuit board of the power supply circuit according to the embodiment. FIG. 3 is a diagram illustrating an equivalent circuit of the power supply circuit according to the embodiment. FIG. 4 is a diagram for explaining how the current flows in the comb-like conductor of the power supply circuit according to the embodiment. FIG. 5 is a perspective view of a specific example of the power supply circuit according to the embodiment. FIG. 6 is a table showing resistance characteristics of the comb-like conductors of the power supply circuit according to the embodiment. FIG. 7 is a chart illustrating filter characteristics of the power supply circuit according to the embodiment. FIG. 8 is a chart illustrating an example of a change in filter characteristics of the power supply circuit according to the embodiment. (Part 1) FIG. 9 is a chart illustrating an example of a change in filter characteristics of the power supply circuit according to the embodiment. (Part 2) FIG. 10 is a chart illustrating an example of a change in filter characteristics of the power supply circuit according to the embodiment. (Part 3) FIG. 11 is a diagram illustrating another configuration example of the power supply circuit according to the embodiment. (Part 1) FIG. 12 is a diagram illustrating another configuration example of the power supply circuit according to the embodiment. (Part 2)

(Embodiment)
Hereinafter, preferred embodiments of the disclosed technology will be described in detail with reference to the accompanying drawings. FIG. 1 is a side view illustrating a configuration example of a power supply circuit according to the embodiment. A power supply circuit 100 in FIG. 1 includes a printed circuit board 101. On the printed circuit board 101, the power supply terminals of the ICs 102 and 103 are mounted via surface mounting bumps 102a and 103a. A power supply connector may be mounted instead of the IC 103. For example, a power supply IC (not shown) is mounted on the printed circuit board 101, and power is supplied from the power supply IC to the power supply line 105.

  The power supply circuit 100 is provided in an electronic device (not shown) and supplies power to each part of the electronic device. Electronic devices include communication devices that handle high frequencies, such as mobile phone terminals. Mobile phone terminals are required to reduce the size of the built-in power supply circuit 100.

  The printed board 101 is a multilayer board and has a plurality of layers. A power supply line 105 is formed on the first layer of the printed circuit board 101, and the power supply line 105 is connected to power supply terminals (bumps 102 a and 103 a) of the ICs 102 and 103 through vias 104. The power line 105 has a predetermined wiring pattern when viewed from the plane of the printed circuit board 101.

  A land 106 is provided on the second layer of the printed circuit board 101. The land 106 has a wiring pattern having the same shape as the power supply line 105 along the wiring pattern of the power supply line 105.

  A ground (GND) surface 107 is provided on the third layer of the printed circuit board 101. The GND surface 107 is provided on the entire surface (solid) of the printed circuit board 101. Further, a portion of the GND surface 107 is removed from the GND surface 107 at a position corresponding to the wiring pattern of the power supply line 105, whereby a comb-like conductor 110 (see FIG. 2) is formed. . The comb-like conductor 110 is electrically connected to the wiring pattern of the land 106 through the via 108.

  In the example of FIG. 1, the GND surface 107 and the comb-like conductor 110 are provided on the third layer of the printed circuit board 101. However, the present invention is not limited thereto, and may be provided on the front surface (back surface) of the printed circuit board 101.

  FIG. 2 is a perspective view illustrating a configuration example of each layer of the printed circuit board of the power supply circuit according to the embodiment. The power supply line 105 provided in the first layer of the printed circuit board 101 has a wiring pattern having a predetermined length L and width W. The lands 106 provided in the second layer of the printed circuit board 101 are arranged in the same shape as the power supply lines 105 at positions immediately below the power supply lines 105 in the first layer. That is, the land 106 has a width W similar to that of the power supply line 105 and is provided along the length L direction.

  A GND surface 107 is provided on the entire third layer of the printed circuit board 101. In addition, a comb-like conductor 110 is formed in a portion of the GND surface 107 located immediately below the power supply line 105 along the length L direction of the wiring pattern of the power supply line 105.

  The comb-shaped conductor 110 is provided with a minute shape within the range of the size (length L and width W) of the power supply line 105 by a left-handed medium method (metamaterial). In the example of FIG. 2, the comb-like conductor 110 is provided with the same length L and width W as the power supply line 105. The comb-shaped conductor 110 is formed by removing a pattern in a meandering manner from the meandering portion of the GND surface 107 directly below the power supply line 105. The meander-shaped pattern-extracted portion (non-conductive portion 120) is a single continuous line that meanders in the region of the width W and the length L of the power line 105.

  As a result, the comb-shaped conductor 110 has a plurality of comb-tooth portions 110 a and 110 b that protrude from the GND surface 107 in directions opposite to each other when viewed in the width W direction of the power supply line 105. The comb-tooth portions 110 a and 110 b have a pattern that is alternately projected along the length L direction of the power supply line 105. The adjacent comb tooth portions 110a and 110b have a predetermined interval (pitch) p by pattern removal. The slit width is s. The comb-tooth portions 110a and 110b of the comb-shaped conductor 110 have a shape in which one end portion (base end) protrudes from the GND surface 107 and the free end is opened (not connected to the adjacent comb-tooth portion). Each of the comb-tooth portions 110 a and 110 b has a shape that is not continuous (not connected) with respect to the length L direction of the power supply line 105.

  The midpoint portion 110 c of the comb-shaped conductor 110, that is, the midpoint portion 110 c of the comb-shaped conductor 110 located immediately below the center portion of the length L of the power line 105 is connected to the land 106 via the via 108. Is electrically connected. In the example of FIG. 2, the middle point portion 110c is connected to a pair of adjacent comb teeth portions 110a and 110b with a wiring pattern, and one end of the via 108 is connected to the wiring pattern (middle point portion 110c). .

  FIG. 3 is a diagram illustrating an equivalent circuit of the power supply circuit according to the embodiment. Between the first-layer power line 105 and the second-layer land 106, a predetermined capacitance (C 1) is provided between the layers by the dielectric of the printed circuit board 101 along the direction of the length L of the power line 105. In addition, a GND surface 107 is formed on the entire surface of the third layer of the printed circuit board 101, and the power supply line 105 becomes a ground surface with good characteristics.

  The second layer land 106 is connected to the third layer GND surface 107 via a via 108, and the via 108 has a predetermined inductor L2. Of the third-layer GND surface 107, the position immediately below the power supply line 105 is a comb-shaped conductor 110, and a plurality of comb-tooth portions 110 a and 110 b are formed along the length L of the power supply line 105. Yes. Accordingly, the comb-shaped conductor 110 has a plurality of inductors L3 along the direction of the length L of the power supply line 105. By using this comb-like conductor 110, an LC filter in which low-pass filters are connected in multiple stages can be obtained, and the power supply noise removal frequency can be widened.

  The via 108 connects the land 106 of the second layer and the midpoint portion 110c of the comb-like conductor 110 of the third layer at the midpoint position in the length L direction of the power supply line 105 of the first layer. . As a result, since the GND plane 107 having a large area is connected by one via 108, the component of the inductor L2 in the LC filter can be increased, and the power supply noise removal frequency can be widened. In this regard, conventionally, by providing a plurality of vias on a wide GND surface, the inductors become parallel and the inductance component becomes small, so that it is not possible to increase the bandwidth.

  FIG. 4 is a diagram for explaining how the current flows in the comb-like conductor of the power supply circuit according to the embodiment. 4 shows a partially enlarged view of the comb-like conductor 110 of FIG. A return current (high-frequency current) flows through the GND surface 107, and the return current flows through the end portions of the comb teeth portions 110a and 110b due to the skin effect in the comb teeth portions 110a and 110b of the comb-shaped conductor 110 (see FIG. Middle arrow 401).

  As a result, the return current flows through the solid GND surface 107 as the electric charge concentrates on the comb-like conductor 110. At this time, stray capacitance is generated by magnetic field coupling (reference numeral 402 in the figure) between the adjacent comb-tooth portions 110a and 110b of the comb-shaped conductor 110 to generate a common mode current, and the mutual inductance (L3 component) can be increased.

  As described above, the comb-like conductor 110 is formed on the third-layer GND surface 107 immediately below the power supply line 105, so that the third-layer GND surface 107 and the GND surface 107 are formed by the comb-like conductor 110. The inductor L3 can be formed. The GND surface 107 according to the embodiment is not formed in a linear shape as in the prior art to obtain an inductance component to form an LC low-pass filter, but causes a deterioration in characteristics as a GND plane in the case of a linear GND. There is no.

  FIG. 5 is a perspective view of a specific example of the power supply circuit according to the embodiment. The example of a dimension of each part is demonstrated using FIG. In FIG. 5, only the configuration of each layer corresponding to the power supply line 105 is extracted and described. For example, a solid GND surface 107 is formed around the third layer of the comb-like conductor 110, but the illustration is omitted.

The wiring pattern of the power line 105 has a length L: 50 mm, a width W: 2 mm, and a thickness: 0.4 mm.
The wiring pattern of the land 106 is also the same size as the power line 105. The region of the comb-like conductor 110 provided on a part of the GND surface 107 is also the same dimension as the power line 105

The width of the comb-tooth portions 110a and 110b of the comb-shaped conductor 110: 0.1 mm, the interval (pitch): 0.1 mm, and meandering 1 when the comb-shaped conductor 110 portion of the GND surface 107 is removed from the pattern 1 Total length of the meander-shaped part of the book (non-conductive part 120): 475 mm
The characteristics of the printed circuit board 101 are as follows: number of layers: 3 layers, substrate thickness: 0.4 mm, dielectric constant: 3.95, Tan δ: 0.012
The wiring pattern (conductor) is made of material: Cu 5.8e7 s / m, thickness: 0.018 mm.
The vias 104 and 108 have a diameter of 0.06 mm.

  FIG. 6 is a table showing resistance characteristics of the comb-like conductors of the power supply circuit according to the embodiment. The horizontal axis represents frequency (GHz) and the vertical axis represents resistance value (Ω). The resistance characteristics of the embodiment as seen in the dimensions (length 50 mm, width 2 mm) shown in FIG. 5 can be made substantially the same by the difference of several Ω from the characteristics in which the entire surface of the layer is solid GND.

  On the other hand, in the case of a meander shape having a predetermined length that meanders GND in an area having the same dimensions (50 mm in length and 2 mm in width), the resistance value increases to 50Ω because the line width is thin. . This meander-like GND has a degraded GND characteristic as compared with a solid GND.

  FIG. 7 is a chart illustrating filter characteristics of the power supply circuit according to the embodiment. The horizontal axis represents frequency (GHz) and the vertical axis represents attenuation (dB), which indicates low-pass filter characteristics. According to the characteristics of the power supply circuit according to the embodiment, the inductor L3 can be enlarged by the comb-shaped conductor 110, and thereby the noise removal frequency band can be widened (for example, the band 701 of −20 dB in the figure). . f0 is the resonance frequency of the filter.

  In contrast, the conventional (mushroom type EBG) has a smaller inductance component than that of the embodiment, and the band of noise removal is narrow.

  FIG. 8 is a chart illustrating an example of a change in filter characteristics of the power supply circuit according to the embodiment. FIG. 8 shows that the filter characteristic is changed by changing the length L of the power supply line 105 (and the land 106 and the comb-shaped conductor 110). Here, according to the length L of the power supply line 105, the land 106 and the comb-shaped conductor 110 are also set to the same length as the power supply line 105.

  The resonance frequency f0 is changed by changing the length L of the power supply line 105 (and the land 106 and the comb-like conductor 110). For example, when the length L is 10 mm, f0: 1.65 GHz, bandwidth 801, length L: 25 mm, f0: 0.85 GHz, bandwidth 802, and length L: 50 mm, f0: 0. 5 GHz and bandwidth 803.

  The resonance frequency f0 depends on the inductance component (L3 in FIG. 3) in the comb-like conductor 110 corresponding to the length L, which is an inductance component, and the capacitance (the length L and the width W of the power supply line 105). It is determined by the calculation formula of 1 / 2π√CL.

  FIG. 9 is a chart illustrating an example of a change in filter characteristics of the power supply circuit according to the embodiment. FIG. 9 shows changes in filter characteristics when the number of vias 108 is increased. As shown in FIG. 5 and the like, the number of vias 108 is the largest in attenuation and has a wide band. When the number of vias 108 connecting the land 106 and the comb-shaped conductor 110 is increased to 2 or 3 at intervals of 5 mm along the length L direction, the resonance frequency moves to the high frequency side and attenuates. It has been shown that the amount decreases and narrows.

  FIG. 10 is a chart illustrating an example of a change in filter characteristics of the power supply circuit according to the embodiment. FIG. 10 shows that the filter characteristics are changed by changing the slit width s (see FIG. 2) of the comb-like conductor 110. By changing the slit width s described above from 0.1 mm to 0.3 mm in units of 0.05 mm, the resonance frequency and the band can be varied.

  FIG. 11 is a diagram illustrating another configuration example of the power supply circuit according to the embodiment. In FIG. 11, the above-described power supply lines 105 are provided as a first-layer power supply line 105a, a third-layer power supply line 105b, and a fifth-layer power supply line 105c. The lands 106 are provided as the second-layer land 106a, the fourth-layer land 106b, and the sixth-layer land 106c. In the seventh layer, the GND surface 107 and the comb-like conductor 110 are provided. Each layer in FIG. 11 shows only the width W portion of the power supply line 105 in the printed circuit board 101.

  Between the power supply line 105 (105a to 105c) of each layer and the land 106 (106a to 106c) of the layer adjacent to the power supply line 105 (105a to 105c), the capacitors C11 to C13 corresponding to the capacitor C1 described above. , C21, C22 are formed. In addition, each land 106 (106a to 106c) is connected to the midpoint portion 110c of the comb-like conductor 110 formed in a part of the GND 108 via the vias 108a to 108c corresponding to the via 108 described above.

  With the configuration shown in FIG. 11, the capacitor C <b> 1 (C <b> 11 to C <b> 13, C <b> 21, C <b> 22) can be increased by providing the power supply line 105 and the land 106 as a multilayer using a multilayer substrate. By forming the power supply line 105 and the land 106 using a plurality of layers of a multilayer substrate including a larger number of layers, not limited to the total of seven layers shown in FIG. 11, it is possible to obtain a capacity suitable for the desired filter characteristics. become able to.

  FIG. 12 is a diagram illustrating another configuration example of the power supply circuit according to the embodiment. FIG. 12 shows an example in which a three-layer printed circuit board 101 is used, the size of the first-layer power supply line 105 is changed, and a plurality of lands 106 a to 106 f are dividedly arranged below the power-supply line 105. Each layer in FIG. 12 shows only the width W portion of the power supply line 105 in the printed circuit board 101.

  For example, the power supply line 105 in the first layer has a length L of 30 mm and a width W of 10 mm. The third-layer GND surface 107 has the same size as the power supply line 105. In the illustrated example, a plurality of (six in the illustrated example) lands 106a to 106f are provided on the second layer, and one size has a length of 10 mm and a width of 2 mm.

  Capacitors C11 to C16 corresponding to the above-described capacitor C1 are formed between the first-layer power line 105 and the plurality of lands 106 (106a to 106f) of the second layer. Each land 106 (106a to 106f) is connected to a comb-like conductor 110 formed in a part of the GND 108 via vias 108a to 108f corresponding to the vias 108 described above.

  In the width W direction of the power supply line 105, three lands 106a, 106c, and 106e (and lands 106b, 106d, and 106f) are arranged side by side. Correspondingly, three comb-shaped conductors 110A to 110C are formed on the GND surface 107 of the third layer along the width direction W of the power supply line 105 (toward the length L).

  The plurality of lands 106a to 106f are connected to the comb-shaped conductors 110A to 110C through vias 108a to 108f (inductance components L21 to L26). For example, the land 106a is connected to the comb-shaped conductor 110A via the via 108a (inductance component L21).

  In the example of FIG. 12, lands 106a and 106b are connected to one comb-like conductor 110A through two vias 108a and 108b (connection points 110ca and 110cb). The comb-shaped conductors 110A, 110B, and 110C are connected to each other through a solid GND surface 107 (inductance component L31).

  As shown in FIG. 12, the land 106 may be divided according to the size of the power supply line 105, the capacitances (C11 to C16) can be increased as in FIG. 11, and the inductance components L21 to L26 can be increased. Can also be increased. In this way, by forming the plurality of lands 106 and the plurality of comb-like conductors 110A to 110C in the lower layer of the power supply line 105 in accordance with the size of the power supply line 105, the capacitance suitable for the desired filter characteristics and Inductance can be obtained.

  Moreover, it can also be set as the structure which has both the structure of FIG. 11 and the structure of FIG. 12, an inductor and a capacitance component can be set more flexibly, and a filter characteristic can be varied now.

  According to the embodiment described above, the comb layer includes a land corresponding to the size of the power line on the GND layer of the printed circuit board, a comb tooth in the length direction of the power line, and a land immediately below the power line. The conductor is formed, and the land and the comb-like electrode are connected. As a result, it is possible to obtain inductance and capacitance components necessary for noise removal from the power supply line with a simple structure, and to obtain desired low-pass filter characteristics. That is, a predetermined capacity can be obtained between layers inside the printed circuit board. Further, the comb-shaped conductor has a plurality of comb teeth in the length direction of the power supply line, and can take a large inductance component. Since the comb-like conductor is not DC-connected to the power supply line, high-frequency noise can be removed from the power supply line regardless of the impedance of the power supply line and the load impedance, and the DC characteristics of the power supply line are deteriorated. There is nothing.

  In addition, the capacitance and inductance components of the filter are obtained using the layers inside the printed circuit board, and the filter can be placed near the power supply terminal of the IC, reducing the amount of unnecessary inductors and simplifying circuit design. It becomes possible to become. In addition, it is not necessary to secure a mounting space for electronic components such as a bypass capacitor on the surface layer of the printed circuit board, and the printed circuit board can be reduced in size and hardly affected by external noise.

  In addition, since the GND layer is a solid entire surface GND, and a comb-like conductor is formed along a power supply line on a part of the GND using a left-handed medium method (metamaterial), the GND surface is excellent. A GND characteristic can be obtained. Conventionally, a GND line that is an LC low-pass filter in which GND is linearly formed and has an inductance component is weak as a GND plane. However, this embodiment can improve this point.

  In addition, the comb-like conductor can increase the inductance component within a limited region, and a circuit configuration in which the LC low-pass filter is connected in multiple stages along the length of the power supply line. Thereby, the high frequency noise of a power supply line can be removed over a wide band (for example, several hundred MHz to several GHz). As a result, high-frequency noise in a wide band can be removed while obtaining good GND characteristics.

  The comb-like conductor can be easily formed by removing a meander pattern from the solid GND by a left-handed medium technique. As described above, it is possible to remove broadband high-frequency noise while reducing the size of the printed circuit board.

  Further, by changing the length of the power supply line, the number of lands connecting between the lands and the comb-like conductor, and the slit width of the comb-like conductor, high-frequency noise in a desired band can be removed. Furthermore, by forming the power supply line and land in a plurality of layers and connecting them to the GND layer, the capacitance between the layers can be increased and the filter characteristics can be varied. Further, the filter characteristics can be varied by providing a plurality of lands in a layer immediately below the power supply line according to the size of the power supply line.

  The electronic device of the embodiment can be applied to electronic devices that handle high frequencies, can be applied to communication devices such as mobile phone terminals, and various electronic devices such as computer devices, and a power supply circuit can be applied to various electronic devices of these electronic devices. Supply power to the circuit. According to the embodiment described above, it is possible to reduce high-frequency noise radiated from the power supply line that receives this power supply. In addition, since the power supply circuit according to the embodiment has a structure in which a filter is formed inside the printed circuit board, the power supply circuit is not easily affected by noises that arrive at the power supply circuit from various electronic circuits or from outside the electronic device.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary note 1) In a power supply circuit that removes power supply noise using a multilayer printed circuit board,
A first layer in which a power line is formed;
A second layer in which a land corresponding to the size of the power supply line is formed immediately below the power supply line;
A third layer in which a ground surface is formed under the land, and
The land is connected to the ground plane via a via;
A plurality of comb-like conductive conductors having a predetermined slit width along the length direction of the power line corresponding to the size of the power line at a position directly below the power line in the ground plane Body,
And having a predetermined filter characteristic.

(Appendix 2) The power supply line has a predetermined length and width,
The land is formed at a position directly below the power line within the same length and width as the power line,
The power circuit according to appendix 1, wherein the comb-like conductor is formed at a position immediately below the power line within a range of a length and a width of the power line.

(Supplementary note 3) The power supply circuit according to supplementary note 1 or 2, wherein the land is connected to the comb-like conductor through one via at a central position in a length direction of the power supply line. .

(Supplementary note 4) The power supply circuit according to any one of supplementary notes 1 to 3, wherein the ground plane is formed on the entire surface of the third layer.

(Additional remark 5) The resonance frequency of a filter can be changed based on the length of the said power supply line, the said land, and the said comb-tooth shaped conductor, It is any one of Additional remark 1-4 characterized by the above-mentioned. Power supply circuit.

(Supplementary note 6) The power supply circuit according to any one of Supplementary notes 1 to 4, wherein a resonance frequency of the filter can be changed based on the slit width of the comb-like conductor.

(Supplementary note 7) The power supply circuit according to any one of supplementary notes 1 to 6, wherein the power supply line and the land are formed in a plurality of layers so as to be adjacent to each other.

(Supplementary Note 8) The land has a plurality of the land divided within the length and width of the power supply line at a position directly below the power supply line.
The comb-like conductor has a plurality connected to the plurality of lands along a length direction of the power supply line at a position directly below the power supply line.
The power supply circuit according to any one of appendices 2 to 7, characterized in that:

(Supplementary note 9) Any one of Supplementary notes 1 to 7, wherein the comb-like conductor is formed by removing a pattern of one meander-like non-conductor portion meandering in the length direction of the power supply line. The power supply circuit as described in one.

(Supplementary note 10) An electronic apparatus comprising the multilayer printed circuit board of the power supply circuit described in any one of Supplementary notes 1 to 9, and an electronic circuit that operates based on power supply of the power supply circuit. .

(Additional remark 11) The said electronic device is a mobile telephone terminal which performs high frequency communication, The electronic device of Additional remark 10 characterized by the above-mentioned.

DESCRIPTION OF SYMBOLS 100 Power supply circuit 101 Printed circuit board 104,108 Via 105 Power supply line 106 Land 107 GND surface 110 Comb-shaped conductor 110a, 110b Comb-tooth part 110c Midpoint part 120 Non-conductor part

Claims (9)

In a power supply circuit that removes power supply noise using a multilayer printed circuit board,
A first layer in which a power line is formed;
A second layer in which a land corresponding to the size of the power supply line is formed immediately below the power supply line;
A third layer in which a ground surface is formed under the land, and
The land is connected to the ground plane via a via;
A plurality of comb-like conductive conductors having a predetermined slit width along the length direction of the power line corresponding to the size of the power line at a position directly below the power line in the ground plane Body,
And having a predetermined filter characteristic. The power line has a predetermined length and width;
The land is formed at a position directly below the power line within the same length and width as the power line,
2. The power supply circuit according to claim 1, wherein the comb-like conductor is formed at a position directly below the power supply line and within a range of a length and a width of the power supply line.   3. The power supply circuit according to claim 1, wherein the land is connected to the comb-like conductor through one via at a central position in a length direction of the power supply line.   The power supply circuit according to claim 1, wherein the ground plane is formed on the entire surface of the third layer.   5. The power supply circuit according to claim 1, wherein a resonance frequency of the filter can be changed based on the length of the power supply line, the land, and the comb-like conductor.   The power supply circuit according to claim 1, wherein a resonance frequency of the filter can be changed based on the slit width of the comb-like conductor.   The power supply circuit according to claim 1, wherein the power supply line and the land are formed in a plurality of layers so as to be adjacent to each other. The land has a plurality of parts divided within the length and width of the power supply line at a position directly below the power supply line,
The comb-like conductor has a plurality connected to the plurality of lands along a length direction of the power supply line at a position directly below the power supply line.
The power supply circuit according to any one of claims 2 to 7, wherein:   9. An electronic apparatus comprising: the multilayer printed circuit board of the power supply circuit according to claim 1; and an electronic circuit that operates based on power supply of the power supply circuit.

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