JP2008118059A - Common mode choke coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a common mode choke coil without changing characteristics thereof even when a deviation occurs in a planar position of a spiral shape conductor. <P>SOLUTION: The common mode choke coil has a first coil 140 including spiral shape conductors 141 and 142, and a second coil 150 including spiral shape conductors 151 and 152. The spiral shape conductors 141 and 151 are opposed to each other in the laminating direction across a space of the spiral shape conductor 152, and the spiral shape conductors 142 and 152 are opposed to each other in a laminating direction across a space of the spiral shape conductor 141. Further, an inner periphery and an outer periphery of the spiral shape conductor 141 and an outer periphery and an inner periphery of the spiral shape conductor 142 are opposed to each other in the laminating direction, respectively, and an inner periphery and an outer periphery of the spiral shape conductor 151 and an outer periphery and an inner periphery of the spiral shape conductor 152 are opposed to each other in the laminating direction, respectively. <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. 9 is a circuit diagram of a general differential transmission circuit.

  The differential transmission circuit shown in FIG. 9 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. 10 is a schematic cross-sectional view for explaining the structure of a general laminated common mode choke coil.

  As shown in FIG. 10, in the laminated common mode choke coil, a first conductor layer 31 and a second conductor layer 32 are embedded in an insulator 30, and these are opposed to each other in the lamination direction. The conductor layer 31 is provided with a coil made of a spiral conductor 41, and the conductor layer 32 is provided with a coil made of a spiral conductor 42. The spiral 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 spiral conductor 41 and the spiral conductor 42 oppose should be increased.

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

  In order to solve this problem, each coil has a two-layer structure as shown in FIG. In the example shown in FIG. 11, one coil is constituted by two spiral conductors 51 and 52, and the other coil is constituted by two spiral conductors 53 and 54. According to this, since the number of turns of the entire coil can be increased while securing the wiring width of the spiral conductors 51 to 54, it is possible to realize downsizing.

  However, when such a structure is employed, the facing area between the spiral conductors to be magnetically coupled becomes insufficient. That is, although the spiral conductor 52 constituting one coil and the spiral conductor 53 constituting the other coil face each other in the stacking direction, the spiral conductor 51 and the spiral conductor 54 should be magnetically coupled. Do not face other spiral conductors directly. For this reason, there was a problem that sufficient magnetic coupling could not be obtained.

In order to solve this problem, as shown in FIG. 12, the radial positions of the spiral conductors 51 and 52 may be shifted, and the radial positions of the spiral conductors 53 and 54 may be shifted (Patent Document 4). reference). If such a structure is adopted, since the spiral conductors 51 and 52 face the spiral conductors 53 and 54, respectively, magnetic coupling can be enhanced.
JP-A-8-203737 JP 2005-12071 A Japanese Patent Laid-Open No. 2005-12072 JP 2005-223262 A

  However, since the laminated common mode choke coil is manufactured by laminating insulating layers on which spiral conductors are formed, misalignment in the plane direction inevitably occurs between the spiral conductors.

  FIG. 13 is a schematic cross-sectional view showing a state where the spiral conductor 52 shown in FIG. 12 is shifted to the left side. As shown in FIG. 13, when the spiral conductor 52 is displaced, the area where the spiral conductor 52 and the spiral conductor 54 face each other decreases, and the magnetic coupling between them decreases. In addition, a part of the spiral conductor 52 is interposed between the spiral conductor 51 and the spiral conductor 53, and the magnetic coupling between them is also lowered. Such a decrease in magnetic coupling becomes more prominent as the misalignment increases, and there is a problem that the characteristics change depending on the degree of misalignment.

  The present invention has been made to solve such problems, and an object of the present invention is to provide a common mode choke coil whose characteristics do not change even when a planar position of a spiral conductor is displaced.

  A common mode choke coil according to the present invention includes a first coil including stacked first and second spiral conductors, and a second coil including stacked third and fourth spiral conductors. A laminated common mode choke coil, wherein the first spiral conductor and the third spiral conductor face each other in the stacking direction through a gap between the second spiral conductors, The spiral conductor and the fourth spiral conductor face each other in the stacking direction through a gap between the third spiral conductor, and the inner and outer peripheral portions of the first spiral conductor and the first spiral conductor The outer peripheral portion and the inner peripheral portion of the spiral conductor of 2 face each other in the stacking direction, and the inner peripheral portion and the outer peripheral portion of the third spiral conductor and the fourth spiral shape. The outer peripheral portion and inner peripheral portion of the body, characterized in that facing each of the stacking direction.

  According to the present invention, since the inner peripheral portion and the outer peripheral portion of the first spiral conductor and the outer peripheral portion and the inner peripheral portion of the second spiral conductor face each other in the laminating direction, the first spiral conductor Even if the planar position of the second spiral conductor is slightly deviated, the facing area between the first spiral conductor and the third spiral conductor does not change. Similarly, since the inner peripheral portion and the outer peripheral portion of the third spiral conductor and the outer peripheral portion and the inner peripheral portion of the fourth spiral conductor face each other in the stacking direction, the third spiral conductor and the fourth spiral conductor are arranged. Even if the planar position of the spiral conductor is slightly deviated, the facing area between the second spiral conductor and the fourth spiral conductor does not change.

  As a result, even if a misalignment in the planar direction occurs in each spiral conductor, the magnetic coupling between the first coil and the second coil does not change. Thus, according to the present invention, it is possible to provide a common mode choke coil having stable characteristics.

  In the present invention, the first spiral conductor and the third spiral conductor have substantially the same shape, and the second spiral conductor and the fourth spiral conductor have substantially the same shape. Preferably there is. According to this, it becomes possible to enhance the magnetic coupling between the first coil and the second coil.

  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.

  As described above, according to the present invention, since the magnetic coupling does not change even when each spiral conductor is misaligned in the plane direction, it is possible to provide a common mode choke coil having stable characteristics. It becomes.

  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 is insulated from the internal electrodes 131 to 134 formed on the surfaces of the insulating layers 121 to 124 and the spiral conductors 141 and 142 formed on the surfaces of the insulating layers 122 and 121, respectively. Spiral conductors 151 and 152 formed on the surfaces of the layers 124 and 123, respectively.

  The spiral conductor 141 and the spiral conductor 142 are connected via a through-hole conductor (not shown), thereby constituting one coil 140 (first coil). Similarly, the spiral conductor 151 and the spiral conductor 152 are also connected through a through-hole conductor (not shown), thereby constituting one coil 150 (second coil).

  As shown in FIG. 1, the spiral conductor 141 constituting the first coil 140 and the spiral conductor 151 constituting the second coil 150 have the same shape except for the lead portions to the internal electrodes 131 and 132. Have. Similarly, the spiral conductor 142 constituting the first coil 140 and the spiral conductor 152 constituting the second coil 150 have the same shape except for the lead portions to the internal electrodes 133 and 134. .

  These spiral conductors 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 first coil 140 composed of the spiral conductors 141 and 142 has one end connected to the internal electrode 131 and the other end connected to the internal electrode 133. The second coil conductor 150 formed of the spiral conductors 151 and 152 has one end connected to the internal electrode 132 and the other end connected to the internal electrode 134.

  When viewed from the arrow A shown in FIG. 1, the coils 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 coils 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 B cross section shown in FIG. 4 is a plan view showing an overlap of the spiral conductor 141 and the spiral conductor 142, FIG. 5 is a plan view showing an overlap of the spiral conductor 152 and the spiral conductor 141, and FIG. 6 is a spiral conductor. FIG. 15 is a plan view showing an overlap between 151 and a spiral conductor 152;

As shown in FIG. 3, in the common mode choke coil 100 according to the present embodiment, the relationship between the conductor width L of each spiral conductor and the conductor spacing S on the same plane is L> S.
Is set to The adjacent spiral conductors are arranged so that one covers the other conductor as viewed from the stacking direction. As a result, the spiral conductor 141 constituting the first coil 140 and the spiral conductor 151 constituting the second coil 150 are arranged in the stacking direction via the gap between the spiral conductors 142 as indicated by an arrow C1. Will face each other. Similarly, the spiral conductor 142 constituting the first coil 140 and the spiral conductor 152 constituting the second coil 150 are arranged in the stacking direction via the gap between the spiral conductor 151 as indicated by an arrow C2. Will face each other.

  The relationship between adjacent spiral conductors will be described in detail as follows.

  First, paying attention to the spiral conductor 141 and the spiral conductor 142, as shown in FIG. 4, the spiral conductor 142 is disposed so as to cover between the conductors of the spiral conductor 141, and between the conductors of the spiral conductor 142. A spiral conductor 141 is disposed so as to cover. As a result, the inner peripheral portion of the spiral conductor 141 faces the outer peripheral portion of the spiral conductor 142, and the outer peripheral portion of the spiral conductor 141 faces the inner peripheral portion of the spiral conductor 142. The overlap between the inner peripheral part of the spiral conductor 141 and the outer peripheral part of the spiral conductor 142 is indicated by an arrow D1 in FIG. Further, the overlap between the outer peripheral portion of the spiral conductor 141 and the inner peripheral portion of the spiral conductor 142 is indicated by an arrow D2 in FIG.

  Here, the “inner peripheral portion” and “outer peripheral portion” of the spiral conductor are, as shown in FIG. 7, when one spiral conductor is divided in the conductor width direction, the portion 161 located on the inner peripheral side and Each is defined as a portion 162 located on the outer peripheral side. The positional relationship between the inner periphery and the outer periphery in the cross-sectional view is also partially shown in FIG.

  Similarly, paying attention to the spiral conductor 152 and the spiral conductor 141, as shown in FIG. 5, the spiral conductor 141 is arranged so as to cover the conductors of the spiral conductor 152, and the conductor of the spiral conductor 141 A spiral conductor 152 is disposed so as to cover the space. As a result, the inner periphery of the spiral conductor 152 faces the outer periphery of the spiral conductor 141, and the outer periphery of the spiral conductor 152 faces the inner periphery of the spiral conductor 141. The overlap between the inner periphery of the spiral conductor 152 and the outer periphery of the spiral conductor 141 is indicated by an arrow D3 in FIG. Further, the overlap between the outer peripheral portion of the spiral conductor 152 and the inner peripheral portion of the spiral conductor 141 is indicated by an arrow D4 in FIG.

  Similarly, when attention is paid to the spiral conductor 151 and the spiral conductor 152, the spiral conductor 152 is disposed so as to cover between the conductors of the spiral conductor 151 as shown in FIG. A spiral conductor 151 is disposed so as to cover between the conductors. As a result, the inner peripheral portion of the spiral conductor 151 faces the outer peripheral portion of the spiral conductor 152, and the outer peripheral portion of the spiral conductor 151 faces the inner peripheral portion of the spiral conductor 152. The overlap between the inner periphery of the spiral conductor 151 and the outer periphery of the spiral conductor 152 is indicated by an arrow D5 in FIG. Further, the overlap between the outer peripheral portion of the spiral conductor 151 and the inner peripheral portion of the spiral conductor 152 is indicated by an arrow D6 in FIG.

  Note that one of the two adjacent spiral conductors is counterclockwise from the inner periphery toward the outer periphery, while the other is counterclockwise from the outer periphery toward the inner periphery. For this reason, it cannot arrange | position so that one may completely cover between the other conductors, and it becomes impossible to cover some conductors in the area | regions E1-E3 shown in FIGS.

The overlap between the adjacent spiral conductors is such that the sum of the inner peripheral portion and the outer peripheral portion (eg, D1 + D2) is LS.
Defined by Therefore, when the center in the line width direction of one spiral conductor coincides with the center in the line width direction between the other spiral conductors, the overlap in the inner periphery and the overlap in the outer periphery are both ( L-S) / 2
It becomes.

  The above is the configuration of the common mode choke coil 100 according to the present embodiment.

  In the common mode choke coil 100 having such a configuration, even if a misalignment in the planar direction occurs in each spiral conductor, a change in characteristics due to misalignment hardly occurs. FIG. 8 is a diagram for explaining this, and schematically shows a state in which the spiral conductor 141 is shifted to the left side.

  As shown in FIG. 8, when the spiral conductor 141 is shifted to the left side, in the area F1 on the left side of the common mode choke coil 100, the overlaps D1 and D4 decrease and D2 and D3 increase. Conversely, in the area F2 on the right side of the common mode choke coil 100, the overlaps D1, D4 increase and D2, D3 decrease. However, the overlap C1 of the spiral conductors 141 and 151 and the overlap C2 of the spiral conductors 142 and 152 are not changed in any area. For this reason, the magnetic coupling between the first coil 140 and the second coil 150 is not substantially changed.

  In addition, since the overlap between adjacent spiral conductors does not change with respect to D1 to D4 as a whole, the stray capacitance between them does not substantially change.

The allowable range of misalignment is determined by the relationship between the conductor width L and the conductor interval S of the spiral conductor. As described above, when designed so that the center in the line width direction of one spiral conductor coincides with the center in the line width direction between the other spiral conductors, the overlap in the inner periphery and the overlap in the outer periphery are , Both (LS) / 2
Therefore, this value is an allowable range of misalignment. Therefore, the above value may be set larger than the assumed maximum value of misalignment. As an example, if the conductor width L of the spiral conductor is 10 μm and the conductor spacing S is 6 μm,
(LS) / 2 = 2 μm
Thus, the misalignment of 2 μm can be absorbed.

  As described above, according to the common mode choke coil 100 according to the present embodiment, even when a misalignment in the planar direction occurs in each spiral conductor, a change in characteristics due to misalignment hardly occurs.

  In addition, in this embodiment, since the spiral conductors 141 and 151 have substantially the same shape, and the spiral conductors 142 and 152 have substantially the same shape, high magnetic coupling is obtained. In addition, the characteristics of the first coil 140 and the second coil 150 can be matched.

  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 B cross section shown in FIG. FIG. 6 is a plan view showing an overlap of a spiral conductor 141 and a spiral conductor 142. FIG. 6 is a plan view showing an overlap of a spiral conductor 152 and a spiral conductor 141. FIG. 5 is a plan view showing an overlap of a spiral conductor 151 and a spiral conductor 152. It is a schematic diagram for demonstrating the definition of the inner peripheral part and outer peripheral part of a spiral conductor. 4 is a schematic cross-sectional view showing a state where a spiral conductor 141 of the common mode choke coil 100 is shifted to the left side. 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. It is a typical schematic sectional view for explaining the structure of a common mode choke coil having a two-layered coil structure. It is a typical schematic sectional view for explaining the structure of a modified example of a common mode choke coil having a two-layered coil structure. It is typical sectional drawing which shows the state which the spiral conductor 52 shown in FIG. 12 shifted | deviated to the left side.

Explanation of symbols

11, 12 Signal line 13 Output buffer 14 Input buffer 20 Common mode choke coil 30 Insulator 32, 32 Conductor layers 41, 42, 51-54 Spiral conductor 100 Common mode choke coils 101-104 External electrodes 111, 112 Substrate 121- 125 Insulating layers 131 to 134 Internal electrode 140 First coil 150 Second coil 141, 142, 151, 152 Spiral conductor 161 Inner peripheral portion 162 Outer peripheral portion

Claims (3)

A laminated common mode choke coil comprising a first coil including stacked first and second spiral conductors and a second coil including stacked third and fourth spiral conductors. And
The first spiral conductor and the third spiral conductor face each other in the stacking direction through a gap between the second spiral conductors,
The second spiral conductor and the fourth spiral conductor face each other in the stacking direction through a gap between the third spiral conductors,
The inner periphery and outer periphery of the first spiral conductor and the outer periphery and inner periphery of the second spiral conductor face each other in the stacking direction,
The common mode choke coil, wherein an inner peripheral portion and an outer peripheral portion of the third spiral conductor and an outer peripheral portion and an inner peripheral portion of the fourth spiral conductor face each other in the stacking direction.   The first spiral conductor and the third spiral conductor have substantially the same shape, and the second spiral conductor and the fourth spiral conductor have substantially the same shape. The common mode choke coil according to claim 1.   3. 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 coils interposed therebetween.

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