JP6551256B2 - Coil component, circuit board incorporating coil component, and power supply circuit including coil component - Google Patents

Description

  The present invention relates to coil components, and more particularly to coil components that can be used as coupling inductors. The present invention also relates to a circuit board in which such a coil component is embedded, and a power supply circuit including such a coil component.

  Coil components called coupling inductors are sometimes used as smoothing coils for switching power supplies such as DC / DC converters. As described in Patent Document 1, the coupling inductor is a magnetic coupling of windings wound in opposite directions to each other, and when current flows through one of the windings, the other winding is generated by the electromotive force. A current also flows through the wire. For this reason, if it is used as a smoothing coil of a switching power supply, it is possible to reduce the peak of the inrush current.

JP, 2015-130472, A

  However, the coil component described in Patent Document 1 has a problem that the magnetic coupling rate is too high depending on the application because the number of turns of the two planar spiral conductors wound concentrically is the same. That is, in the coupling inductor, since the leakage magnetic flux component which is not magnetically coupled brings about a smoothing action, in order to obtain the desired characteristics, it is necessary to weaken the magnetic coupling ratio to some extent, thereby securing a sufficient leakage magnetic flux component. However, since the coil component described in Patent Document 1 has a high magnetic coupling rate, it has been difficult to obtain a sufficient smoothing action.

  Moreover, since the coil component described in Patent Document 1 has a configuration in which planar spiral conductors are laminated, there is a problem that it is difficult to reduce the height.

  Accordingly, an object of the present invention is to provide a coil component that is easy to adjust the magnetic coupling rate and is suitable for low profile. It is another object of the present invention to provide a circuit board in which such a coil component is embedded, and a power supply circuit including such a coil component.

  The coil component according to the present invention includes a first coil pattern including first and second planar spiral conductors connected in series, and a second coil pattern including third and fourth planar spiral conductors connected in series. And the first and third planar spiral conductors are concentrically wound in one direction concentrically on a predetermined plane, and the second and fourth planar spiral conductors are concentrically arranged on the predetermined plane. The first planar spiral conductor includes a first portion adjacent to the third planar spiral conductor and a second portion not adjacent to the third planar spiral conductor. The fourth planar spiral conductor includes a third portion adjacent to the second planar spiral conductor and a fourth portion not adjacent to the second planar spiral conductor.

  The circuit board according to the present invention is characterized in that the above-mentioned coil component is embedded.

  According to the present invention, since the part of the double spiral conductor wound concentrically has a structure adjacent to each other and the other part is not adjacent to each other, the ratio of the adjacent part and the non-adjacent part It is possible to arbitrarily adjust the magnetic coupling rate by adjusting. In addition, since the two double spiral conductors are formed on the same plane, there is no need to stack a plurality of planar spiral conductors, which makes it possible to reduce the height.

  In the present invention, it is preferable that the first part and the third part have equal lengths, and the second part and the fourth part have equal lengths. According to this, the characteristics of the first coil pattern and the second coil pattern can be matched.

  In the present invention, the number of turns of the first flat spiral conductor is one or more more than the number of turns of the third flat spiral conductor, and the number of turns of the fourth flat spiral conductor is the second flat It is preferable that the number of turns of the spiral conductor is one or more turns. According to this, since the magnetic coupling rate is sufficiently lowered, it is possible to enhance the smoothing action due to the leakage magnetic flux component.

  In the present invention, preferably, the pattern shapes of the first and third planar spiral conductors and the pattern shapes of the second and fourth planar spiral conductors are point-symmetrical to each other. According to this, since the shapes of the first coil pattern and the second coil pattern match, it becomes possible to match the characteristics of both accurately.

  In the present invention, it is preferable that the second portion has more turns than the first portion, and the fourth portion has more turns than the third portion. According to this, since the magnetic coupling rate is sufficiently lowered, it is possible to enhance the smoothing action due to the leakage magnetic flux component.

  The coil component according to the present invention includes a first external terminal connected to an inner peripheral end of the first planar spiral conductor, and a second external terminal connected to an inner peripheral end of the second planar spiral conductor. And a third external terminal connected to the inner peripheral end of the third planar spiral conductor, and a fourth external terminal connected to the inner peripheral end of the fourth planar spiral conductor. preferable. According to this, it can be used as a four-terminal type coupling inductor.

  In this case, it further includes first and second magnetic members sandwiching the first and second coil patterns, wherein the second magnetic member is the first, second, third and fourth planar spiral conductors. The first, second, third and fourth external terminals have first, second, third and fourth openings respectively exposing the inner peripheral end of the first and second external terminals. It is preferable to be embedded in the second, third and fourth openings. According to this, it is possible to efficiently dissipate heat from the opening provided in the second magnetic member.

  Here, the first magnetic member and the second magnetic member may be made of different magnetic materials. In this case, the second magnetic member may be made of a resin containing a magnetic material.

  Here, the coil component according to the present invention is provided in an inner diameter portion of the first and third planar spiral conductors, and a third magnetic member that connects the first magnetic member and the second magnetic member; It is preferable to further provide a fourth magnetic member provided in the inner diameter portion of the second and fourth planar spiral conductors and connecting the first magnetic member and the second magnetic member. According to this, since the closed magnetic path is formed by the first to fourth magnetic members, high magnetic characteristics can be obtained.

  Here, it is preferable that the same metal material as the metal material constituting the first and second coil patterns is exposed at the first to fourth external terminals. This eliminates the need for plating on the first to fourth external terminals, thereby reducing the manufacturing cost. In this case, the metal material is preferably copper (Cu).

  A power supply circuit according to the present invention comprises: a pair of input power supply wires consisting of first and second power supply wires; a pair of output power supply wires consisting of third and fourth power supply wires; and the coil component described above The first power supply wiring is connected to the first external terminal, the second power supply wiring is connected to the fourth external terminal, and the third power supply wiring is connected to the second external terminal. The fourth power supply line is connected to the third external terminal. According to this, it is possible to make the coil component according to the present invention function as a coupling inductor.

  Thus, according to the present invention, it is possible to provide a coil component that is easy to adjust the magnetic coupling rate and that is suitable for low profile. In addition, according to the present invention, it is possible to provide a circuit board in which such a coil component is embedded, and a power supply circuit including such a coil component.

FIG. 1 is a perspective view showing the appearance of a coil component 10 according to a preferred embodiment of the present invention. FIG. 2 is an exploded perspective view of the coil component 10. FIG. 3 is a plan view for explaining the shapes of the first and second coil patterns 21 and 22. As shown in FIG. FIG. 4 is a cross-sectional view taken along the line AA shown in FIG. FIG. 5 is an equivalent circuit diagram of the coil component 10. FIG. 6 shows a modified example of the first and second coil patterns 21 and 22 and shows an example in which the magnetic coupling is further strengthened. FIG. 7 shows a modified example of the first and second coil patterns 21 and 22 and shows an example in which the magnetic coupling is further weakened. FIG. 8 is a graph showing the relationship between the total extension of the adjacent portion C and the inductance and magnetic coupling rate. FIG. 9 is a cross-sectional view illustrating a configuration example of the circuit board 80 in which the coil component 10 is embedded. FIG. 10 is a plan view for explaining the relationship between the coil component 10 embedded in the circuit board 80 and the power supply wiring. FIG. 11 is a plan view showing an example in which the third power supply wiring V3 and the fourth power supply wiring V4 are short-circuited.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing an appearance of a coil component 10 according to a preferred embodiment of the present invention. FIG. 2 is an exploded perspective view of the coil component 10.

  The coil component 10 according to the present embodiment is a chip component that can be used as a coupling inductor, and as shown in FIGS. 1 and 2, the first and second magnetic members 11 and 12 and the magnetic members 11, 12 and a first coil pattern 21 and a second coil pattern 22 embedded in an insulating resin 40. Note that, in FIG. 2, in the insulating resin 40, portions other than the portions covering the upper and lower sides of the coil patterns 21 and 22 are not illustrated in consideration of the legibility of the drawing.

  The magnetic member 11 is a substrate made of a magnetic material such as sintered ferrite. In the manufacturing process of the coil component 10, the coil members 21 and 22 and the magnetic member 12 are sequentially formed on the upper surface of the magnetic member 11 as a substrate. On the other hand, the magnetic member 12 is a composite member made of a resin containing ferrite powder or metal magnetic powder. When using metal magnetic powder, it is preferable to use a permalloy material. As the resin, it is preferable to use a liquid or powder epoxy resin.

  The first coil pattern 21 includes first and second planar spiral conductors 31 and 32 connected in series. The second coil pattern 22 includes third and fourth planar spiral conductors 33 and 34 connected in series. Although details will be described later, the first flat spiral conductor 31 and the third flat spiral conductor 33 are concentrically wound, and the second flat spiral conductor 32 and the fourth flat spiral conductor 34 are concentrically wound. It will be turned. These first to fourth planar spiral conductors 31 to 34 are formed on the same plane, and each of them is made of a good conductor such as copper (Cu) formed using an electrolytic plating method or the like.

  The upper surfaces of the first to fourth planar spiral conductors 31 to 34 are covered with the second magnetic member 12 via the insulating resin 40. The magnetic member 12 is provided with four openings 12a to 12d. The openings 12a to 12d are provided at positions overlapping the inner peripheral ends of the first to fourth planar spiral conductors 31 to 34 in plan view, and the first to fourth external terminals 51 to 54 are embedded therein, respectively. It is done. Thereby, the inner peripheral ends of the first to fourth planar spiral conductors 31 to 34 are connected to the first to fourth external terminals 51 to 54, respectively.

  The 1st-4th external terminals 51-54 are comprised by good conductors, such as copper (Cu), similarly to the planar spiral conductors 31-34. In the present embodiment, the first to fourth external terminals 51 to 54 and the first to fourth planar spiral conductors 31 to 34 are made of the same metal material as each other, and this metal material is used as it is for the first to fourth 4 are exposed to the external terminals 51 to 54. The top surfaces of the first to fourth external terminals 51 to 54 are exposed from the top surface of the second magnetic member 12 and constitute substantially the same plane as the top surface of the second magnetic member 12.

  Further, a third magnetic member 13 made of the same material as that of the second magnetic member 12 is embedded in the inner diameter portions of the first and third planar spiral conductors 31 and 33. Similarly, a fourth magnetic member 14 made of the same material as the second magnetic member 12 is embedded in the inner diameter portions of the second and fourth planar spiral conductors 32 and 34. The third and fourth magnetic members 13 and 14 magnetically connect the first magnetic member 11 and the second magnetic member 12 through the through holes provided in the insulating resin 40, thereby forming a closed magnetic path. Play a role in forming.

  FIG. 3 is a plan view for explaining the shapes of the first and second coil patterns 21 and 22. 4 is a cross-sectional view taken along the line AA shown in FIG.

  As shown in FIG. 3, the first coil pattern 21 includes a first planar spiral conductor 31 formed in the planar region 61 and a second planar spiral conductor 32 formed in the planar region 62, which are It has the structure connected in series. As described above, the inner peripheral end 31 a of the first planar spiral conductor 31 is connected to the first external terminal 51, and the inner peripheral end 32 a of the second planar spiral conductor 32 is connected to the second external terminal 52. . When the inner peripheral end 31a is a starting point and the inner peripheral end 32a is an end point, the first planar spiral conductor 31 is wound clockwise (clockwise), while the second planar spiral conductor 32 is left-handed. It is wound around (counterclockwise). In the first coil pattern 21, the part formed in the overlapping region 63 where the planar region 61 and the planar region 62 overlap belongs to both the first planar spiral conductor 31 and the second planar spiral conductor 32. ing.

  Similarly, the second coil pattern 22 includes a third planar spiral conductor 33 formed in the planar region 61 and a fourth planar spiral conductor 34 formed in the planar region 62, which are connected in series. It has the following configuration. As described above, the inner peripheral end 33 a of the third planar spiral conductor 33 is connected to the third external terminal 53, and the inner peripheral end 34 a of the fourth planar spiral conductor 34 is connected to the fourth external terminal 54. . When the inner peripheral end 33a is a starting point and the inner peripheral end 34a is an end point, the third planar spiral conductor 33 is wound clockwise (clockwise), while the fourth planar spiral conductor 34 is left-handed. It is wound around (counterclockwise). In the second coil pattern 22, the portion formed in the overlapping region 63 where the planar region 61 and the planar region 62 overlap belongs to both the third planar spiral conductor 33 and the fourth planar spiral conductor 34. ing.

  In the present embodiment, the number of turns of the first and fourth planar spiral conductors 31 and 34 is greater than the number of turns of the second and third planar spiral conductors 32 and 33. Here, when the position passing through the center point B is defined as the outer peripheral end of each of the planar spiral conductors 31 to 34, the number of turns of the first and fourth planar spiral conductors 31 and 34 is 2+ (3/8) turns. The number of turns of the second and third planar spiral conductors 32 and 33 is 1+ (1/8). Therefore, the number of turns of each of the first and second coil patterns 21 and 22 is 3.5 turns in total. The difference between the number of turns of the first and fourth planar spiral conductors 31 and 34 and the number of turns of the second and third planar spiral conductors 32 and 33 is 1+ (¼) turns.

  The first planar spiral conductor 31 and the third planar spiral conductor 33 are concentrically wound clockwise in the planar region 61. On the other hand, the second planar spiral conductor 32 and the fourth planar spiral conductor 34 are concentrically wound counterclockwise in the planar region 62. Here, "clockwise" and "counterclockwise" are winding directions when the inner peripheral ends 31a and 33a are the starting point and the inner peripheral ends 32a and 34a are the ending points. Therefore, conversely, if the inner peripheral ends 32a and 34a are the starting points and the inner peripheral ends 31a and 33a are the end points, the first and third planar spiral conductors 31 and 33 are "counterclockwise" The fourth planar spiral conductors 32 and 34 are “clockwise”.

  Therefore, for example, when current flows from the inner peripheral end 31a of the first planar spiral conductor 31, the magnetic flux generated in the first planar spiral conductor 31 and the magnetic flux generated in the second planar spiral conductor 32 are directed to each other. On the contrary, a magnetic flux loop through the magnetic members 11 to 14 is formed. Similarly, when current flows from the inner peripheral end 34a of the fourth planar spiral conductor 34, the magnetic flux generated in the fourth planar spiral conductor 34 and the direction of the magnetic flux generated in the third planar spiral conductor 33 are opposite to each other. Thus, a magnetic flux loop through the magnetic members 11 to 14 is formed. The direction of the magnetic flux generated when current flows from the inner peripheral end 31a of the first planar spiral conductor 31 and the direction of the magnetic flux generated when current flows from the inner peripheral end 34a of the fourth planar spiral conductor 34 Are opposite to each other.

  In the present embodiment, the number of turns of the first planar spiral conductor 31 is one turn or more than the number of turns of the third planar spiral conductor 33, and the outer peripheral ends of the first and third spiral conductors 31 and 33 Are present at the same turn position, the portion of the first planar spiral conductor 31 corresponding to the turn difference from the third planar spiral conductor 33 is wound around the inner periphery. Become. For this reason, the inner diameter portion in which the third magnetic member 13 is disposed is defined as a region surrounded by the innermost turn of the first planar spiral conductor 31. In other words, the inner diameter portion where the third magnetic member 13 is disposed does not contact the innermost turn of the third planar spiral conductor 33. The entire area of the innermost circumferential turn of the third planar spiral conductor 33 is always located outside the innermost circumferential turn of the first planar spiral conductor 31. Accordingly, at least the innermost turn of the first planar spiral conductor 31 is not adjacent to the third planar spiral conductor 33.

  Similarly, the number of turns of the fourth planar spiral conductor 34 is one turn or more than the number of turns of the second planar spiral conductor 32, and the outer peripheral ends of the second and fourth spiral conductors 32, 34 are mutually connected. Since it exists in the same turn position, the part equivalent to the turn difference with the 2nd plane spiral conductor 32 among the 4th plane spiral conductors 34 will be collectively wound by the inner peripheral part. Therefore, the inner diameter portion in which the fourth magnetic member 14 is disposed is defined as a region surrounded by the innermost turns of the fourth planar spiral conductor 34. In other words, the inner diameter portion in which the fourth magnetic member 14 is disposed is not in contact with the innermost turn of the second planar spiral conductor 32. The entire area of the innermost turn of the second flat spiral conductor 32 is always located outside the innermost turn of the fourth flat spiral conductor 34. Accordingly, at least the innermost turn of the fourth planar spiral conductor 34 is not adjacent to the second planar spiral conductor 32.

  Here, when the first planar spiral conductor 31 is divided into a first portion 71 adjacent to the third planar spiral conductor 33 and a second portion 72 not adjacent to the third planar spiral conductor 33, In the embodiment, the number of turns of the first portion 71 is 1+ (1/8) turns, and the number of turns of the second portion 72 is 1+ (1/4) turns. Therefore, the number of turns of the second portion 72 is larger than the number of turns of the first portion 71. On the other hand, all the turns (1+ (1/8) turns) of the third planar spiral conductor 33 are adjacent to the first planar spiral conductor 31.

  Similarly, when the fourth planar spiral conductor 34 is divided into a third portion 73 adjacent to the second planar spiral conductor 32 and a fourth portion 74 not adjacent to the second planar spiral conductor 32, In the embodiment, the number of turns of the third portion 73 is 1+ (1/8) turns, and the number of turns of the fourth portion 74 is 1+ (1/4) turns. For this reason, the number of turns of the fourth portion 74 is greater than the number of turns of the third portion 73. On the other hand, all the turns (1+ (1/8) turns) of the second flat spiral conductor 32 are adjacent to the fourth flat spiral conductor 34.

  As described above, since the number of turns of the first planar spiral conductor 31 is larger than that of the third planar spiral conductor 33, the second portion 72 not adjacent to the third planar spiral conductor 33 is caused by the difference. Exists. Similarly, since the fourth planar spiral conductor 34 has more turns than the second planar spiral conductor 32, there is a fourth portion 74 not adjacent to the second planar spiral conductor 32 due to the difference. Do. The first and third portions 71, 73 provide high magnetic coupling because the first coil pattern 21 and the second coil pattern 22 are adjacent in the planar direction, but the second and fourth portions 72, 74 Since the first coil pattern 21 and the second coil pattern 22 are not adjacent to each other in the plane direction, if this portion is long, the magnetic coupling is lowered.

  Further, in the present embodiment, the number of turns of the first planar spiral conductor 31 and the number of turns of the fourth planar spiral conductor 34 match, and the numbers of the second planar spiral conductor 32 and the third planar spiral conductor 33 The number of turns is the same. The first and third planar spiral conductors 31 and 33 are wound clockwise, and the second and fourth planar spiral conductors 32 and 34 are wound counterclockwise. The pattern shape of the third planar spiral conductors 31 and 33 and the pattern shape of the second and fourth planar spiral conductors 32 and 34 are point-symmetric with respect to the center point B.

  The above is the configuration of the coil component 10 according to the present embodiment. With this configuration, for example, when current flows from the first external terminal 51 to the second external terminal 52, the third external terminal 53 is magnetically coupled between the first coil pattern 21 and the second coil pattern 22. To the fourth external terminal 54, a reverse current flows. In other words, when current flows from the first external terminal 51 to the second external terminal 52, current in the same direction flows from the fourth external terminal 54 to the third external terminal 53.

  FIG. 5 is an equivalent circuit diagram of the coil component 10 according to the present embodiment.

  As shown in FIG. 5, the coil component 10 according to the present embodiment has an ideal transformer portion L1 magnetically coupled and a leakage inductance component L2 generating a leakage flux. The ideal transformer section L1 is a component that is magnetically coupled in the opposite direction to each other when the first and fourth external terminals 51 and 54 are on the input side.

  When the coil component 10 is used as a coupling inductor, the current is divided by the ideal transformer L1 and smoothed by the leakage inductance component L2. Therefore, in order to obtain desired characteristics, it is necessary to secure the leakage inductance component L2 by adjusting the magnetic coupling rate to be reduced to some extent.

  In the present embodiment, the magnetic coupling rate can be adjusted by the number of turns of the first to fourth planar spiral conductors 31 to 34. This is because when the number of turns is adjusted, the total extension of the adjacent portion C of the first coil pattern 21 and the second coil pattern 22 changes. The adjacent portion C is a portion where the first coil pattern 21 and the second coil pattern 22 are adjacent to each other, and the total extension is defined by the length along the winding direction. And if the total extension of the adjacent part C is lengthened, the magnetic coupling between the first coil pattern 21 and the second coil pattern 22 becomes strong, and conversely, if the total extension of the adjacent part C is shortened, the first The magnetic coupling between the coil pattern 21 and the second coil pattern 22 is weakened.

  6 and 7 show modified examples of the first and second coil patterns 21 and 22. FIG. Among these, FIG. 6 shows an example in which the magnetic coupling is further strengthened, and FIG. 7 shows an example in which the magnetic coupling is further weakened.

  In the example shown in FIG. 6, the number of turns of the first and fourth planar spiral conductors 31 and 34 is 2+ (5/8), and the number of turns of the second and third planar spiral conductors 32 and 33 is 1+. (3/8) Turn. Therefore, the total number of turns of the first and second coil patterns 21 and 22 is 4 turns. In the example shown in FIG. 6, the number of turns of the first and third portions 71, 73 is 1+ (3/8), and the number of turns of the second and fourth portions 72, 74 is 1+ (1/4) ) It is a turn. On the other hand, all the turns (1+ (3/8) turns) of the third and second planar spiral conductors 33 and 32 are adjacent to the first and fourth planar spiral conductors 31 and 34, respectively.

  According to such a layout, since the total extension of the adjacent portion C is longer than the example shown in FIG. 3, the magnetic coupling between the first coil pattern 21 and the second coil pattern 22 becomes strong. However, since the number of turns of the first and second coil patterns 21 and 22 is not so different from the layout shown in FIG. 3, the obtained inductance is almost the same as the case of using the layout shown in FIG. .

  In the example shown in FIG. 7, the number of turns of the first and fourth planar spiral conductors 31, 34 is 2+ (5/8) turns, and the number of turns of the second and third planar spiral conductors 32, 33 is seven. / 8 turns. Therefore, the number of turns of each of the first and second coil patterns 21 and 22 is 3.5 turns in total. In the example shown in FIG. 7, the number of turns of the first and third portions 71 and 73 is 7/8, and the number of turns of the second and fourth portions 72 and 74 is 1+ (3/4). . On the other hand, all the turns (7/8 turns) of the third and second planar spiral conductors 33 and 32 are adjacent to the first and fourth planar spiral conductors 31 and 34, respectively.

  According to such a layout, since the total extension of the adjacent part C is shorter than the example shown in FIG. 3, the magnetic coupling between the first coil pattern 21 and the second coil pattern 22 is weakened. However, since the number of turns of the first and second coil patterns 21 and 22 is not much different from the layout shown in FIG. 3, the obtained inductance is almost the same as the case of using the layout shown in FIG. .

  FIG. 8 is a graph showing the relationship between the total extension of the adjacent portion C and the inductance and magnetic coupling rate.

  The data shown in FIG. 8 is obtained by calculating the inductance and the magnetic coupling rate of each of six types of coil parts having different total extensions of the adjacent portions C by simulation. The number of turns of the first and second coil patterns 21 and 22 is designed to be within a range of 3 to 5 turns in total.

  As shown in FIG. 8, it can be confirmed that the magnetic coupling rate increases in proportion to the total extension of the adjacent portion C. On the other hand, regarding the inductance, no significant change is seen even if the total extension of the adjacent portion C changes. This means that by adjusting the total extension of the adjacent portion C without largely changing the number of turns, the magnetic coupling rate can be largely changed without significantly affecting the inductance. Therefore, it is possible to adjust the leakage inductance component L2 while maintaining the inductance at a predetermined value. In the coil component 10 according to the present embodiment, the magnetic coupling rate can be adjusted in a range of approximately 20 to 70% due to its structure, and various device needs can be met.

  As described above, according to the coil component 10 according to the present embodiment, since the magnetic coupling rate can be arbitrarily adjusted, it is possible to obtain the leakage inductance component L2 corresponding to the required characteristics. Moreover, since the 1st-4th plane spiral conductors 31-34 are formed on the same plane, it is also possible to implement | achieve low profile. In addition, since the first to fourth planar spiral conductors 31 to 34 can be formed at the same time during manufacturing, there is almost no characteristic difference between the first and second coil patterns 21 and 22 due to manufacturing variations. It does not occur. Further, the distance between the first and second magnetic members 11 and 12 is not different between the first and second coil patterns 21 and 22.

  In the present embodiment, the pattern shapes of the first and third planar spiral conductors 31 and 33 and the pattern shapes of the second and fourth planar spiral conductors 32 and 34 are point-symmetric with respect to the center point B as a symmetry point. Thus, the first coil pattern 21 and the second coil pattern 22 have completely the same shape. For this reason, the characteristic variation between the first coil pattern 21 and the second coil pattern 22 hardly occurs.

  Moreover, in the present embodiment, the first to fourth external terminals 51 to 54 are directly exposed on the upper surface of the magnetic member 12 instead of using L-shaped terminal electrodes such as general coil parts. Therefore, the DC resistance is not increased by the L-shaped terminal electrode.

  FIG. 9 is a cross-sectional view showing a configuration example of a circuit board 80 in which the coil component 10 according to the present embodiment is embedded.

  A circuit board 80 shown in FIG. 9 includes a resin substrate 81 and a resin layer 82, and the coil component 10 is embedded between them. Specifically, the coil component 10 is mounted on the upper surface of the resin substrate 81 in a face-up manner, so that the external terminals 51 to 54 provided on the coil component 10 are exposed upward. Then, the resin layer 82 is provided on the resin substrate 81 so as to embed the coil component 10. In the resin layer 82, through holes 83 for exposing the external terminals 51 to 54 are formed. The wiring pattern 84 formed on the upper surface of the resin layer 82 is connected to the external terminals 51 to 54 of the coil component 10 through the through hole 83.

  As described above, when the coil component 10 is used by being embedded in the circuit board 80, since the solder is not used for the connection between the external terminals 51 to 54 and the wiring pattern 84, the surface of the external terminals 51 to 54 needs to be plated with tin. The copper (Cu) constituting the external terminals 51 to 54 can be exposed as it is.

  If a switching power supply is mounted on such a circuit board 80, a switching power supply including a coupling inductor can be realized by a single circuit board. Since a large current flows through the coupling inductor for the switching power supply, a relatively large amount of heat is generated. The heat generated in this way is mainly dissipated from the external terminals made of metal, but in the coil component 10 according to the present embodiment, the external terminals 51 to 54 are all arranged at the inner diameter portion of the planar spiral conductor in plan view. Thus, the heat accumulated in the coil component 10 can be efficiently released.

  Also, the coil component 10 can be mounted on the surface of the circuit board with the external terminals 51 to 54 facing upward, and in this case, wire bonding can be directly performed to the external terminals 51 to 54. Furthermore, if L-shaped terminal electrodes are connected to the external terminals 51 to 54, ordinary solder mounting is also possible in which the external terminals 51 to 54 are bonded to the circuit board.

  FIG. 10 is a plan view for explaining the relationship between the coil component 10 embedded in the circuit board 80 and the power supply wiring.

  In the example shown in FIG. 10, on the surface of the circuit board 80, a pair of input power wirings VIN composed of first and second power wirings V1, V2 and a pair of outputs composed of third and fourth power wirings V3, V4. A power supply wiring VOUT is provided. The input power supply wiring VIN is connected to the output terminal of a switching circuit included in the power supply circuit, for example. The output power supply wiring VOUT is connected to, for example, a smoothing capacitor included in the power supply circuit.

  In the present embodiment, the first power supply wiring V1 is connected to the first external terminal 51, the second power supply wiring V2 is connected to the fourth external terminal 54, and the third power supply wiring V3 is connected to the first power supply wiring V3. The fourth power supply wiring V 4 is connected to the second external terminal 52 and connected to the third external terminal 53.

  By performing such connection, when the current output from the switching circuit flows into the first external terminal 51 via the first power supply wiring V1, the magnetic flux generated by the first coil pattern 21 is converted to the second An electromotive force is generated in the coil pattern 22, and the input current is divided into two. The divided current is output from the third and fourth power supply wirings V3 and V4 via the second and third external terminals 52 and 53. On the other hand, when the current output from the switching circuit flows into the fourth external terminal 54 through the second power supply wiring V2, the magnetic flux generated by the second coil pattern 22 causes the first coil pattern 21 to generate an electromotive force. The generated current is divided into two. The divided current is output from the third and fourth power supply wirings V3 and V4 via the second and third external terminals 52 and 53.

  And since the 1st and 2nd coil patterns 21 and 22 have the leakage inductance component L2, it becomes possible to reduce the peak of an inrush current. Depending on the configuration of the power supply circuit, as shown in FIG. 11, the third power supply wiring V3 and the fourth power supply wiring V4 may be short-circuited.

  Thus, the coil component 10 according to the present embodiment is preferably used as a coupling inductor for a power supply circuit.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, in the above-described coil component embodiment, the first and third planar spiral conductors 31 and 33 are concentrically wound clockwise on a predetermined plane, and the second and fourth planar spiral conductors are wound. In the above example, the first and third planar spiral conductors 31 and 33 are rotated counterclockwise, and the second and fourth spiral conductors 31 and 33 are concentrically wound around the predetermined plane. Obviously, the same effect can be obtained even when the planar spiral conductors 32 and 34 are wound clockwise.

  In the example shown in FIG. 9, the coil component 10 is embedded in the circuit board 80, but is an L-shaped terminal that covers the side surface from the upper surface of the coil component 10, and is connected to the external terminals 51 to 54, respectively. By providing a mold terminal, the coil component 10 can be surface-mounted on a circuit board.

DESCRIPTION OF REFERENCE NUMERALS 10 coil parts 11 to 14 magnetic members 12 a to 12 d openings 21 and 22 coil patterns 31 to 34 planar spiral conductors 31 a to 34 a inner circumferential end 40 insulating resin 51 to 54 external terminals 61 and 62 planar area 63 overlapping area 71 first Part 72 Second part 73 Third part 74 Fourth part 80 Circuit board 81 Resin board 82 Resin layer 83 Through hole 84 Wiring pattern B Center point C Adjacent part L1 Ideal transformer part L2 Inductance component V1 to V4 Power supply wiring VIN Input power supply wiring VOUT Output power supply wiring

Claims (12)

A first coil pattern comprising first and second planar spiral conductors connected in series;
A second coil pattern including third and fourth planar spiral conductors connected in series;
The first and third planar spiral conductors are concentrically wound in one direction on a predetermined plane,
The second and fourth planar spiral conductors are concentrically wound in opposite directions on the predetermined plane,
The first planar spiral conductor includes a first portion adjacent to the third planar spiral conductor and a second portion not adjacent to the third planar spiral conductor.
The coil component characterized in that the fourth planar spiral conductor includes a third portion adjacent to the second planar spiral conductor and a fourth portion not adjacent to the second planar spiral conductor.   The coil component according to claim 1, wherein the first portion and the third portion are equal in length to each other, and the second portion and the fourth portion are equal in length to each other. The number of turns of the first planar spiral conductor is one or more more than the number of turns of the third planar spiral conductor,
3. The coil component according to claim 1, wherein the number of turns of the fourth planar spiral conductor is one or more turns larger than the number of turns of the second planar spiral conductor.   The pattern shape of the first and third planar spiral conductors and the pattern shape of the second and fourth planar spiral conductors are point-symmetric with each other. Coil parts described in.   5. The method according to claim 1, wherein the second part has more turns than the first part, and the fourth part has more turns than the third part. Coil parts described in. A first external terminal connected to an inner peripheral end of the first planar spiral conductor;
A second external terminal connected to an inner peripheral end of the second planar spiral conductor;
A third external terminal connected to an inner peripheral end of the third planar spiral conductor;
The coil component according to any one of claims 1 to 5, further comprising: a fourth external terminal connected to an inner peripheral end of the fourth planar spiral conductor. It further comprises first and second magnetic members sandwiching the first and second coil patterns,
The second magnetic member has first, second, third and fourth openings for exposing the inner peripheral ends of the first, second, third and fourth planar spiral conductors, respectively. ,
The coil according to claim 6, wherein the first, second, third and fourth external terminals are embedded in the first, second, third and fourth openings, respectively. parts.   The coil component according to claim 7, wherein the first magnetic member and the second magnetic member are made of different magnetic materials. A third magnetic member provided in an inner diameter portion of the first and third planar spiral conductors and connecting the first magnetic member and the second magnetic member;
A fourth magnetic member provided at an inner diameter portion of the second and fourth planar spiral conductors and connecting the first magnetic member and the second magnetic member is further provided. The coil component as described in 7 or 8.   The first to fourth external terminals are exposed to the same metal material as the metal material constituting the first and second coil patterns. Coil component as described.   A circuit board in which the coil component according to any one of claims 1 to 10 is embedded. A pair of input power supply lines composed of first and second power supply lines;
A pair of output power supply lines consisting of third and fourth power supply lines;
A coil component according to any one of claims 6 to 10,
The first power supply wiring is connected to the first external terminal;
The second power supply wiring is connected to the fourth external terminal;
The third power supply wiring is connected to the second external terminal;
A power supply circuit characterized in that the fourth power supply wiring is connected to the third external terminal.