JP2008108921A - Common mode choke coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a common mode choke coil in which a magnetic coupling between coil conductors is enhanced. <P>SOLUTION: In the laminated type common mode choke coil provided with first and second coil conductors 140, 150 magnetically coupled to each other, the first and second coil conductors 140, 150 are adjacent to each other in a lamination direction S and in a planar direction P. Since the first and second coil conductors 140, 150 are adjacent to each other in the lamination direction S as well as in the planar direction P, an area of a confronting portion of these coil conductors is increased. Thus, it becomes possible to enhance the magnetic coupling as compared with a conventional general common mode choke coil. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a common mode choke coil, and more particularly, to a common mode choke coil with enhanced magnetic coupling between coil conductors.

  In recent years, the USB 2.0 standard and the IEEE 1394 standard are widely used as high-speed signal transmission interfaces, and are used in many digital devices such as personal computers and digital cameras. Unlike the single-ended transmission method that has been common for a long time, interfaces such as the USB 2.0 standard and the IEEE 1394 standard adopt a differential signal method that transmits a differential signal using a pair of signal lines.

  The differential transmission system has an excellent feature that not only the radiation electromagnetic field generated from the signal line is small compared to the single-end transmission system, but also that the differential transmission system is less susceptible to external noise. For this reason, it is easy to reduce the amplitude of the signal, and by shortening the rise time and the fall time due to the small amplitude, it becomes possible to perform signal transmission at a higher speed than the single-ended transmission method.

  FIG. 11 is a circuit diagram of a general differential transmission circuit.

  The differential transmission circuit shown in FIG. 11 includes a pair of signal lines 11 and 12, an output buffer 13 that supplies a differential signal to the signal lines 11 and 12, and an input buffer that receives a differential signal from the signal lines 11 and 12. 14. With this configuration, the input signal IN given to the output buffer 13 is transmitted to the input buffer 14 via the pair of signal lines 11 and 12, and is reproduced as the output signal OUT. Such a differential transmission circuit has a feature that the radiated electromagnetic field generated from the signal lines 11 and 12 is small as described above, but noise common to the signal lines 11 and 12 (common mode noise) is generated. When superposed, a relatively large radiated electromagnetic field is generated. In order to reduce the radiated electromagnetic field generated by the common mode noise, it is effective to insert the common mode choke coil 20 into the signal lines 11 and 12 as shown in FIG.

  The common mode choke coil 20 has a characteristic that an impedance with respect to a differential component (signal) transmitted through the signal lines 11 and 12 is low and an impedance with respect to an in-phase component (common mode noise) is high. For this reason, by inserting the common mode choke coil 20 into the signal lines 11 and 12, the common mode noise transmitted through the pair of signal lines 11 and 12 can be blocked without substantially attenuating the differential signal. . As the common mode choke coil 20, for example, stacked common mode choke coils described in Patent Documents 1 to 3 are known.

  FIG. 12 is a schematic cross-sectional view for explaining the structure of a general laminated common mode choke coil.

As shown in FIG. 12, in the laminated common mode choke coil, the first conductor layer 31 and the second conductor layer 32 are embedded in the insulator 30, and these are opposed to each other in the lamination direction S. . The conductor layer 31 is provided with a spiral coil conductor 41, and the conductor layer 32 is provided with a spiral coil conductor 42. The coil conductors 41 and 42 are adjacent to each other in the stacking direction, and magnetic coupling occurs in the adjacent portions. For this reason, in order to strengthen magnetic coupling, the area of the part which the coil conductor 41 and the coil conductor 42 oppose should just be increased.
JP-A-8-203737 JP 2005-12071 A Japanese Patent Laid-Open No. 2005-12072

  However, since the common mode choke coil is required to be downsized, the widths of the coil conductors 41 and 42 are inevitably reduced. When the widths of the coil conductors 41 and 42 are narrowed, the area of the opposing portion of the coil conductor 41 and the coil conductor 42 is reduced, resulting in a problem that magnetic coupling is lowered.

  The present invention has been made to solve such problems, and an object thereof is to provide a common mode choke coil in which magnetic coupling between coil conductors is enhanced.

  A common mode choke coil according to the present invention is a laminated common mode choke coil including first and second coil conductors that are magnetically coupled to each other, wherein the first and second coil conductors are laminated in a plane and a plane. It is characterized by being adjacent in the direction.

  According to the present invention, since the first and second coil conductors are adjacent not only in the laminating direction but also in the planar direction, the area of the facing portions of these coil conductors is increased. This makes it possible to increase the magnetic coupling as compared with a conventional common mode choke coil.

  In the present invention, it is preferable that the first and second coil conductors have portions alternately arranged in the planar direction. According to this, the opposing area of the first and second coil conductors in the planar direction increases. In addition, since the number of insulating layers does not increase even when the number of turns of the coil is increased, it is possible to suppress an increase in manufacturing cost and meet the demand for a low profile.

  In the present invention, it is also preferable that the first and second coil conductors have portions alternately arranged in the stacking direction. According to this, the opposing area of the 1st and 2nd coil conductors in the lamination direction increases. Moreover, since the planar size does not increase even if the number of turns of the coil is increased, it is possible to meet the demand for miniaturization. Further, since the width of the coil conductor can be increased, the resistance component can be reduced. Furthermore, since a large area surrounded by the coil conductor can be secured, a sufficient magnetic path region can be secured and the impedance to the in-phase signal can be increased.

  Moreover, it is also preferable that the first and second coil conductors are alternately arranged in the planar direction and are alternately arranged in the stacking direction. According to this, the opposing areas of the first and second coil conductors are further increased.

  The common mode choke coil according to the present invention preferably further includes a pair of magnetic substrates provided on both sides in the stacking direction with the first and second coil conductors interposed therebetween. According to this, it is possible to further increase the magnetic coupling between the first and second coil conductors. The first and second coil conductors are preferably insulated by a non-magnetic material. According to this, it is possible to further increase the magnetic coupling between the first and second coil conductors.

  Thus, according to the present invention, since the first and second coil conductors are adjacent not only in the laminating direction but also in the planar direction, the area of the opposing portions of these coil conductors increases. This makes it possible to increase the magnetic coupling as compared with a conventional common mode choke coil.

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

  FIG. 1 is a schematic exploded perspective view showing the structure of a common mode choke coil 100 according to a first preferred embodiment of the present invention, and FIG. 2 is a schematic view showing a state in which the common mode choke coil 100 according to the present embodiment is assembled. It is a perspective view.

  As shown in FIG. 1, the common mode choke coil 100 according to this embodiment includes substrates 111 and 112, insulating layers 121 to 125 provided between the substrates 111 and 112, and a conductor pattern formed on a predetermined insulating layer. Is a laminated common mode choke coil. Here, “stacked common mode choke coil” refers to a common mode choke coil in which a plurality of planar conductor patterns are stacked via an insulating layer, and a common mode in which a conductor is wound around a drum. Differentiated from choke coils.

  The material of the substrates 111 and 112 is not particularly limited, but it is preferable to use a material with high magnetic permeability, for example, a magnetic material such as ferrite. This is because magnetic coupling is enhanced by using a magnetic material as the material of the substrates 111 and 112. The material of the insulating layers 121 to 125 is not particularly limited, but it is preferable to use a nonmagnetic material such as polyimide. This is because the magnetic coupling is enhanced by using a nonmagnetic material as the material of the insulating layers 121 to 125.

  The conductor pattern formed on the insulating layer includes internal electrodes 131 to 134 formed on the surfaces of the insulating layers 121 to 124, partial coil conductors 141, 143, and 152 formed on the surface of the insulating layer 122, and insulating layers. The partial coil conductors 142, 144, 151, and 153 formed on the surface of 123 and the connection conductors 161 and 162 formed on the surfaces of the insulating layers 121 and 124, respectively.

  The partial coil conductors 141, 143, and 152 formed on the surface of the insulating layer 122 are all substantially ring-shaped, and are arranged in parallel along the order of the partial coil conductors 141, 152, and 143 from the inside. The partial coil conductors 142, 144, 151, and 153 formed on the surface of the insulating layer 123 are also substantially annular, and are arranged in parallel so as to follow each other in the order of the partial coil conductors 151, 142, 153, and 144 from the inside. ing.

  Further, the partial coil conductors 151, 142, and 153 are positioned directly above the partial coil conductors 141, 152, and 143 with the insulating layer 123 interposed therebetween.

  The partial coil conductors 141 to 144 are connected via a through-hole conductor (not shown), thereby constituting one coil conductor 140 (first coil conductor). Similarly, the partial coil conductors 151 to 153 are also connected through a through-hole conductor (not shown), thereby constituting one coil conductor 150 (second coil conductor).

  These conductor patterns can be formed on the insulating layer by a so-called thin film process such as sputtering, vapor deposition, or plating. Among these conductor patterns, the internal electrodes 131 to 134 are conductor patterns connected to the external electrodes 101 to 104 shown in FIG. 2, respectively (the external electrodes 101 to 104 are not shown in FIG. 1).

  As shown in FIG. 1, the coil conductor 140 including the partial coil conductors 141 to 144 has one end connected to the internal electrode 131 via the connection conductor 161 and the other end connected to the internal electrode 133. That is, when the internal electrode 131 is the starting point, the partial coil conductors 141, 142, 143, and 144 are wound in this order to reach the internal electrode 133. The coil conductor 150 including the partial coil conductors 151 to 153 has one end connected to the internal electrode 132 via the connection conductor 162 and the other end connected to the internal electrode 134. That is, with the internal electrode 132 as a starting point, the partial coil conductors 151, 152, and 153 are wound in this order to reach the internal electrode 134.

  When viewed from the arrow A1 shown in FIG. 1, the coil conductors 140 and 150 are both wound counterclockwise (counterclockwise) from one end to the other end. Therefore, if the external electrodes 101 and 102 are a pair of input terminals, the coil conductors 140 and 150 are magnetically coupled in the same direction. Here, “magnetic coupling in the same direction as each other” means that magnetic coupling is performed so that the magnetic flux is strengthened with respect to the in-phase component and the magnetic flux is canceled with respect to the differential component.

  FIG. 3 is a cross-sectional view schematically showing the structure of the B1 cross section shown in FIG.

  As shown in FIG. 3, in the common mode choke coil 100 according to the present embodiment, the cross section of the coil conductor 140 and the cross section of the coil conductor 150 are arranged in a staggered pattern in the plane direction P. That is, if the conductor pattern formed on the insulating layer 122 is a conductor layer 171 and the conductor pattern formed on the insulating layer 123 is a conductor layer 172, the partial coil conductors formed on these conductor layers 171 and 172 are either Are alternately arranged in the plane direction P.

  Here, the stacking direction S refers to the direction in which the substrates 111 and 112 and the insulating layers 121 to 125 are stacked (thickness direction), and the plane direction P refers to the surface of the substrates 111 and 112 and the insulating layers 121 to 125. It refers to the parallel direction (plane direction).

  Next, the relationship between the coil conductor 140 and the coil conductor 150 will be described in more detail with reference to FIG. 4 which is an enlarged schematic diagram of the region C1 shown in FIG.

  First, paying attention to the partial coil conductor 142 shown in FIG. 4, the partial coil conductor 142 has a part of the coil conductor 150 (partial coil conductors 151, 153) adjacently disposed on both sides in the plane direction P, and in the stacking direction S. A part of the coil conductor 150 (partial coil conductor 152) is disposed adjacent to one side. That is, the partial coil conductor 142 is adjacent to the coil conductor 150 in three directions. In FIG. 4, the magnetic coupling between the partial coil conductors is schematically shown by arrows.

  Similarly, paying attention to the partial coil conductor 152, a part of the coil conductor 140 (partial coil conductors 141, 143) is adjacently disposed on both sides in the plane direction P, and the partial coil conductor 152 has a coil on one side in the stacking direction S. A part of the conductor 140 (partial coil conductor 142) is adjacently disposed. That is, the partial coil conductor 152 is also adjacent to the coil conductor 140 in three directions.

  Due to the adjacent arrangement in the stacking direction S and the planar direction P, the facing area between the coil conductor 140 and the coil conductor 150 is increased as compared with the conventional common mode choke coil, and as a result, the magnetic coupling between the two is increased. This makes it possible to obtain sufficient magnetic coupling even when the overall size is reduced.

  Moreover, since the coil conductors 140 and 150 are alternately arranged in the plane direction P in the common mode choke coil 100 according to the present embodiment, the number of insulating layers stacked does not increase even if the number of coil turns is increased. For this reason, it is possible to suppress an increase in manufacturing cost and meet the demand for a low profile.

  Next, a second preferred embodiment of the present invention will be described.

  FIG. 5 is a schematic exploded perspective view showing the structure of a common mode choke coil 200 according to the second preferred embodiment of the present invention. The external shape of the common mode choke coil 200 according to the present embodiment is as shown in FIG.

  As shown in FIG. 5, the common mode choke coil 200 according to the present embodiment is different from the common mode choke coil 100 according to the first embodiment in the configuration of the conductor pattern formed in the insulating layers 121 to 124. Since the other points are basically the same as those of the common mode choke coil 100 according to the first embodiment, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, the partial coil conductors 241 and 252 are formed on the surface of the insulating layer 121, the partial coil conductors 242 and 251 are formed on the surface of the insulating layer 122, and the partial coil conductors 244 and 253 are formed on the surface of the insulating layer 123. The partial coil conductors 243 and 254 are formed on the surface of the insulating layer 124.

  All of the partial coil conductors formed on the surfaces of the insulating layers 121 to 124 have a substantially annular shape, and are formed in parallel to each other. In addition, the partial coil conductors 251 and 242 are respectively located immediately above the partial coil conductors 241 and 252 with the insulating layer 122 interposed therebetween. Further, the partial coil conductors 244 and 253 are respectively located immediately above the partial coil conductors 251 and 242 with the insulating layer 123 interposed therebetween. Further, the partial coil conductors 254 and 243 are respectively located immediately above the partial coil conductors 244 and 253 via the insulating layer 124.

  The partial coil conductors 241 to 244 are connected via a through-hole conductor (not shown), thereby constituting one coil conductor 240 (first coil conductor). One end of the coil conductor 240 is connected to the internal electrode 131, and the other end is connected to the internal electrode 133. That is, when the internal electrode 131 is a starting point, the partial coil conductors 241, 242, 243, and 244 are wound in this order to reach the internal electrode 133. On the way, the connection from the partial coil conductor 242 to the partial coil conductor 243 passes through the through-hole conductor SH <b> 1 formed in the insulating layer 123.

  Similarly, the partial coil conductors 251 to 254 are also connected through a through-hole conductor (not shown), thereby constituting one coil conductor 250 (second coil conductor). One end of the coil conductor 250 is connected to the internal electrode 132, and the other end is connected to the internal electrode 134. That is, with the internal electrode 132 as a starting point, the partial coil conductors 251, 252, 253, and 254 are wound in this order to reach the internal electrode 134. On the way, the connection from the partial coil conductor 252 to the partial coil conductor 253 passes through the through-hole conductor SH <b> 2 formed in the insulating layer 122.

  When viewed from the arrow A2 shown in FIG. 5, the coil conductors 240 and 250 are both wound counterclockwise (counterclockwise) from one end to the other end. Therefore, if the external electrodes 101 and 102 are a pair of input terminals, the coil conductors 240 and 250 are magnetically coupled in the same direction.

  FIG. 6 is a cross-sectional view schematically showing the structure of the B2 cross section shown in FIG.

  As shown in FIG. 6, in the common mode choke coil 200 according to the present embodiment, the cross section of the coil conductor 240 and the cross section of the coil conductor 250 are arranged in a staggered manner in the stacking direction S. That is, the conductor patterns formed on the insulating layers 121 to 124 are alternately arranged in the stacking direction S.

  FIG. 7 is an enlarged schematic view of a region C2 shown in FIG.

  First, paying attention to the partial coil conductor 242 shown in FIG. 7, the partial coil conductor 242 has a part of the coil conductor 250 (partial coil conductors 252 and 253) adjacently arranged on both sides in the stacking direction S, A part of the coil conductor 250 (partial coil conductor 251) is adjacently disposed on one side. That is, the partial coil conductor 242 is adjacent to the coil conductor 250 in three directions.

  Similarly, paying attention to the partial coil conductor 251, a part of the coil conductor 240 (partial coil conductors 241 and 244) is adjacently disposed on both sides in the stacking direction S, and the partial coil conductor 251 has a coil on one side in the plane direction P. A part of the conductor 240 (partial coil conductor 242) is adjacently disposed. That is, the partial coil conductor 251 is also adjacent to the coil conductor 240 in three directions.

  The adjacent arrangement in the stacking direction S and the planar direction P increases the facing area between the coil conductor 240 and the coil conductor 250 as in the common mode choke coil 100 according to the first embodiment. Will increase. This makes it possible to obtain sufficient magnetic coupling even when the overall size is reduced.

  Moreover, since the coil conductors 240 and 250 are alternately arranged in the stacking direction S, the plane size of the common mode choke coil 200 according to the present embodiment does not increase even if the number of coil turns is increased. For this reason, it becomes possible to meet the demand for miniaturization. Further, since the width of the coil conductors 240 and 250 can be increased, the resistance component can be reduced. Furthermore, since a large area surrounded by the coil conductor can be secured, a sufficient magnetic path region can be secured and the impedance to the in-phase signal can be increased.

  Next, a preferred third embodiment of the present invention will be described.

  FIG. 8 is a schematic exploded perspective view showing the structure of a common mode choke coil 300 according to a preferred third embodiment of the present invention. The external shape of the common mode choke coil 300 according to the present embodiment is as shown in FIG.

  As shown in FIG. 8, the common mode choke coil 300 according to the present embodiment is different from the common mode choke coil 100 according to the first embodiment in the configuration of the conductor pattern formed in the insulating layers 121 to 124. Since the other points are basically the same as those of the common mode choke coil 100 according to the first embodiment, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  In the present embodiment, the partial coil conductors 341, 343, and 352 are formed on the surface of the insulating layer 121, the partial coil conductors 342, 351, and 353 are formed on the surface of the insulating layer 122, and the partial coil conductors are formed on the surface of the insulating layer 123. 344, 346, 354, and 356 are formed, and partial coil conductors 345, 355, and 357 are formed on the surface of the insulating layer 124.

  All of the partial coil conductors formed on the surfaces of the insulating layers 121 to 124 have a substantially annular shape, and are formed in parallel to each other. Further, the partial coil conductors 351, 342, and 353 are located immediately above the partial coil conductors 341, 352, and 343 with the insulating layer 122 interposed therebetween. Further, the partial coil conductors 346, 356, and 344 are located immediately above the partial coil conductors 351, 342, and 353 with the insulating layer 123 interposed therebetween. Further, the partial coil conductors 357, 345, and 355 are located immediately above the partial coil conductors 346, 356, and 344 with the insulating layer 124 interposed therebetween.

  The partial coil conductors 341 to 346 are connected via a through-hole conductor (not shown), thereby constituting one coil conductor 340 (first coil conductor). One end of the coil conductor 340 is connected to the internal electrode 131, and the other end is connected to the internal electrode 133. That is, with the internal electrode 131 as a starting point, the partial coil conductors 341, 342, 343, 344, 345, and 356 are wound in this order to reach the internal electrode 133. On the way, the connection from the partial coil conductor 343 to the partial coil conductor 344 passes through the through-hole conductor SH3 formed in the insulating layer 122.

  Similarly, the partial coil conductors 351 to 357 are also connected through a through-hole conductor (not shown), thereby constituting one coil conductor 350 (second coil conductor). One end of the coil conductor 350 is connected to the internal electrode 132, and the other end is connected to the internal electrode 134. That is, with the internal electrode 132 as a starting point, the partial coil conductors 351, 352, 353, 354, 355, 356, and 357 are wound in this order to reach the internal electrode 134.

  When viewed from the arrow A3 shown in FIG. 8, the coil conductors 340 and 350 are both wound counterclockwise (counterclockwise) from one end to the other end. Therefore, if the external electrodes 101 and 102 are a pair of input terminals, the coil conductors 340 and 350 are magnetically coupled in the same direction.

  FIG. 9 is a cross-sectional view schematically showing the structure of the B3 cross section shown in FIG.

  As shown in FIG. 9, in the common mode choke coil 300 according to the present embodiment, the cross section of the coil conductor 340 and the cross section of the coil conductor 350 are alternately arranged in the plane direction P and the stacking direction S.

  FIG. 10 is an enlarged schematic view of a region C3 shown in FIG.

  First, paying attention to the partial coil conductor 342 shown in FIG. 10, the partial coil conductor 342 includes a part of the coil conductor 350 (partial coil conductors 351 and 353) adjacently disposed on both sides in the plane direction P and the stacking direction. A part of the coil conductor 350 (partial coil conductors 352 and 356) is adjacently disposed on both sides of S. That is, the partial coil conductor 342 is adjacent to the coil conductor 350 in four directions.

  Similarly, paying attention to the partial coil conductor 356, the partial coil conductor 356 has a part of the coil conductor 340 (partial coil conductors 344 and 346) adjacently disposed on both sides in the plane direction P, and both sides in the stacking direction S. A part of the coil conductor 340 (partial coil conductors 342 and 345) is adjacently disposed. That is, the partial coil conductor 356 is also adjacent to the coil conductor 340 in four directions.

  Due to the adjacent arrangement in the stacking direction S and the planar direction P, the facing area between the coil conductor 340 and the coil conductor 350 is further increased as compared with the common mode choke coils 100 and 200 according to the first and second embodiments. . This makes it possible to further increase the magnetic coupling between the two.

  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 each of the above embodiments, the substrates are provided on both sides of the pair of coil conductors, but one or both of these substrates may be omitted.

1 is a schematic exploded perspective view showing a structure of a common mode choke coil 100 according to a first preferred embodiment of the present invention. 2 is a schematic perspective view showing a state in which a common mode choke coil 100 is assembled. FIG. It is sectional drawing which shows typically the structure of the B1 cross section shown in FIG. It is an expansion schematic diagram of the area | region C1 shown in FIG. It is a substantially exploded perspective view which shows the structure of the common mode choke coil 200 by preferable 2nd Embodiment of this invention. It is sectional drawing which shows typically the structure of B2 cross section shown in FIG. It is an expansion schematic diagram of the area | region C2 shown in FIG. FIG. 6 is a schematic exploded perspective view showing the structure of a common mode choke coil 300 according to a preferred third embodiment of the present invention. It is sectional drawing which shows typically the structure of the B3 cross section shown in FIG. It is an expansion schematic diagram of the area | region C3 shown in FIG. It is a circuit diagram of a general differential transmission circuit. It is a typical schematic sectional view for explaining the structure of a general laminated common mode choke coil.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 12 Signal line 13 Output buffer 14 Input buffer 20 Common mode choke coil 30 Insulator 32, 32 Conductor layer 41, 42 Coil conductor 100, 200, 300 Common mode choke coil 101-104 External electrode 111, 112 Substrate 121-125 Insulating layer 131-134 Internal electrode 140, 240, 340 Coil conductor (first coil conductor)
150, 250, 350 Coil conductor (second coil conductor)
141-144, 151-153, 241-244, 251-254, 341-346, 351-357 Partial coil conductor 161, 162 Connection conductor 171, 172 Conductor layer

Claims (5)

  A laminated common mode choke coil having first and second coil conductors that are magnetically coupled to each other, wherein the first and second coil conductors are adjacent to each other in the laminating direction and the planar direction. Common mode choke coil.   The common mode choke coil according to claim 1, wherein the first and second coil conductors have portions alternately arranged in the planar direction.   The common mode choke coil according to claim 1 or 2, wherein the first and second coil conductors have portions alternately arranged in the stacking direction.   4. The common mode choke coil according to claim 1, further comprising a magnetic substrate provided on both sides in the stacking direction with the first and second coil conductors interposed therebetween. 5.   The common mode choke coil according to any one of claims 1 to 4, wherein the first and second coil conductors are insulated by a non-magnetic material.

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