JP6427770B2 - Common mode noise filter - Google Patents

Description

  The present invention relates to a common mode noise filter used in various electronic devices such as digital devices, AV devices, and information communication terminals.

  As shown in FIG. 10, the conventional common mode noise filter of this type has a first coil 2 and a second coil 3 formed on a plurality of laminated insulator layers 1a to 1g. One coil 2 is configured by connecting the first and second spiral conductors 4a and 4b, and the second coil 3 is configured by connecting the third and fourth spiral conductors 5a and 5b. The spiral conductors 4a and 4b constituting the first coil 2 and the spiral conductors 5a and 5b constituting the second coil 3 are alternately arranged. The insulator layer 1a provided on the lowermost surface and the insulator layer 1g provided on the uppermost surface are made of a magnetic material, and the other insulator layers 1b to 1f are made of a nonmagnetic material. Then, the first spiral conductor 4a and the third spiral conductor 5a are magnetically coupled, and the second spiral conductor 4b and the fourth spiral conductor 5b are magnetically coupled to generate common mode noise. I was trying to remove it.

  As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

JP 2002-373810 A

  In recent high-speed digital signal transmission, as the signal speed increases, impedance matching is required for the transmission line and the components used therein so that the digital signal does not deteriorate due to signal reflection or loss. . Characteristic impedance is defined as an amount that defines the transmission impedance of the transmission line, and is defined as 90Ω for USB and 100Ω for HDMI (registered trademark).

  However, in the above-described conventional common mode noise filter, as shown in FIG. 11, the third spiral conductor 5a and the second spiral conductor 4b constituting different coils are adjacent to each other in the stacking direction. For this reason, stray capacitance C0 is generated between the third spiral conductor 5a and the second spiral conductor 4b, and the characteristic impedance is reduced by this stray capacitance C0. However, there is a problem that the characteristic impedance may not be obtained. FIG. 11 is an equivalent circuit of the conventional common mode noise filter shown in FIG. 10 and shows the positional relationship of the spiral conductors in the stacking direction.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a common mode noise filter capable of obtaining a specified characteristic impedance.

In order to achieve the above object, the present invention sets the thickness of the insulator layer between the second spiral conductor and the third spiral conductor to a value between the first spiral conductor and the second spiral conductor. The second spiral conductor and the third spiral conductor are made thicker than the thickness of the insulator layer between them and the thickness of the insulator layer between the third spiral conductor and the fourth spiral conductor. Was made larger than the distance between the first spiral conductor and the second spiral conductor and the distance between the third spiral conductor and the fourth spiral conductor.

  As described above, the common mode noise filter of the present invention has the distance between the second spiral conductor and the third spiral conductor, the distance between the first spiral conductor and the second spiral conductor, and the first spiral conductor. Since the distance between the third spiral conductor and the fourth spiral conductor is larger than the distance between the second spiral conductor and the third spiral conductor, the stray capacitance between the second spiral conductor and the third spiral conductor can be reduced. As a result, it is possible to prevent the characteristic impedance from being lowered by the above-described method.

1 is an exploded perspective view of a common mode noise filter according to Embodiment 1 of the present invention. Perspective view of the common mode noise filter Equivalent circuit diagram of the common mode noise filter The disassembled perspective view of the common mode noise filter in Embodiment 2 of this invention Equivalent circuit diagram of the common mode noise filter The disassembled perspective view of the common mode noise filter in Embodiment 3 of this invention Equivalent circuit diagram of the common mode noise filter Comparison of characteristic impedance between the common mode noise filter and the conventional common mode noise filter An exploded perspective view showing another example of the common mode noise filter Exploded perspective view of a conventional common mode noise filter Equivalent circuit diagram of the common mode noise filter

(Embodiment 1 )

  FIG. 1 is an exploded perspective view of a common mode noise filter according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of the common mode noise filter.

  As shown in FIGS. 1 and 2, the common mode noise filter according to the first exemplary embodiment of the present invention includes first to fifth insulator layers 11a to 11e and a first insulator layer 11a formed on the first insulator layer 11a. A first coil 14 composed of one spiral conductor 12 and a second spiral conductor 13 formed in the third insulator layer 11c, and a third spiral shape formed in the second insulator layer 11b. A second coil 17 comprising a conductor 15 and a fourth spiral conductor 16 formed on the fourth insulator layer 11d, the first spiral conductor 12, the third spiral conductor 15, The two spiral conductors 13 and the fourth spiral conductor 16 are laminated in this order, and the line widths of the second and fourth spiral conductors 13 and 16 are made to be the same as those of the first and third spiral conductors 12 and 15. It is made thinner than the width. Further, the line width of the first spiral conductor 12 and the line width of the third spiral conductor 15 are substantially the same, and the line width of the second spiral conductor 13 and the line width of the fourth spiral conductor 16 are the same. Are substantially the same.

  Then, the first spiral conductor 12 and the third spiral conductor 15 are magnetically coupled, and the second spiral conductor 13 and the fourth spiral conductor 16 are magnetically coupled, so that the common mode noise is reduced. Try to remove.

  In the above configuration, the first to fifth insulator layers 11a to 11e are formed from the first insulator layer 11a, the second insulator layer 11b, the third insulator layer 11c, and the fourth insulator layer from the bottom. 11d and the 5th insulator layer 11e are laminated | stacked in order, and it is comprised in the sheet form with nonmagnetic materials, such as Cu-Zn ferrite and glass ceramic.

  Further, the first to fourth spiral conductors 12, 13, 15, 16 are each formed by spirally plating or printing a conductive material such as silver. The first spiral conductor 12 is the upper surface of the first insulator layer 11a, the second spiral conductor 13 is the upper surface of the third insulator layer 11c, and the third spiral conductor 15 is the second insulator. The upper surface of the body layer 11b and the fourth spiral conductor 16 are respectively formed on the upper surface of the fourth insulator layer 11d. That is, the spiral conductor constituting the first coil 14 and the spiral conductor constituting the second coil 17 are alternately laminated. Here, a part of the first spiral conductor 12 and the third spiral conductor 15 are arranged at substantially the same position in the top view, and the winding direction is also the same direction. Similarly, a part of the second spiral conductor 13 and the fourth spiral conductor 16 are arranged at substantially the same position in top view, and the winding direction is also the same direction. Further, the line widths of the second and fourth spiral conductors 13 and 16 are made thinner than the line widths of the first and third spiral conductors 12 and 15. At this time, the line width of the first spiral conductor 12 and the line width of the third spiral conductor 15 are substantially the same, and the line width of the second spiral conductor 13 and the line of the fourth spiral conductor 16 are the same. The width is substantially the same.

  The first spiral conductor 12 and the second spiral conductor 13 are connected to each other via two first via electrodes 18 formed in the second insulator layer 11b and the third insulator layer 11c, respectively. Are connected to each other to form a first coil 14. Further, the third spiral conductor 15 and the fourth spiral conductor 16 are connected via two second via electrodes 19 formed in the third insulator layer 11c and the fourth insulator layer 11d. The second coil 17 is configured by being connected to each other.

  The first via electrode 18 is provided at the same position when viewed from above, and the second via electrode 19 is also provided at the same position when viewed from above. In addition, the first via electrode 18 and the second via electrode 19 are formed by drilling holes in predetermined portions of the insulator layer with a laser and filling the holes with silver.

  A sixth insulator layer 20 is provided on each of the lower surface of the first insulator layer 11a and the upper surface of the fifth insulator layer 11e, and the sixth insulator layer 20 is formed of a sheet. And is made of a magnetic material such as Ni-Cu-Zn ferrite. Further, the number of the first to sixth insulator layers 11a to 11e and 20 is not limited to the number shown in FIG. If the first insulator layer 11a, the third insulator layer 11c, and the fifth insulator layer 11e are made of a magnetic material, a nonmagnetic insulator layer and a magnetic insulator layer are alternately formed. In this way, cracks can be prevented from occurring during firing even if the shrinkage rates of the two differ.

  And the main-body part 21 of a common mode noise filter is formed by the above-mentioned structure. Further, first to fourth external electrodes 22 to 25 are provided on both side surfaces of the main body 21, and the first to fourth external electrodes 22 to 25 are first to fourth spiral shapes, respectively. The conductors 12, 13, 15 and 16 are connected. Further, the first to fourth external electrodes 22 to 25 are formed by printing silver on the end face of the main body portion 21, and a nickel plating layer is formed on these surfaces by plating. A low melting point metal plating layer such as tin or solder is formed on the surface of the substrate by plating.

  FIG. 3 is an equivalent circuit diagram of the common mode noise filter according to the first embodiment of the present invention.

As apparent from FIG. 3, the first spiral conductor 12 and the third spiral conductor 15 are affected by the common mode noise that enters from the first external electrode 22 and the third external electrode 24. The second spiral conductor 13 and the fourth spiral conductor 16 are magnetically coupled, and common mode noise can be removed. The equivalent circuit showing the positional relationship of the spiral conductors in the stacking direction is the same as that shown in FIG.

  As described above, in the common mode noise filter according to the first exemplary embodiment of the present invention, the first spiral conductor 12, the third spiral conductor 15, the second spiral conductor 13, and the fourth spiral conductor 16. And the line widths of the second and fourth spiral conductors 13 and 16 are made thinner than the line widths of the first and third spiral conductors 12 and 15, so that the second spiral Since the facing area between the spiral conductor 13 and the third spiral conductor 15 can be reduced, and thereby the stray capacitance between the second spiral conductor 13 and the third spiral conductor 15 can be reduced. The characteristic impedance can be prevented from lowering due to the stray capacitance, and further, the inductance value of the coil can be increased, so that the characteristic impedance can be increased. In which the effect is obtained that sex impedance is obtained.

  Here, the characteristic impedance of transmission lines used for recent high-speed differential signal data transmission is generally 90Ω ± 15% (76.5Ω to 103.5Ω) for USB 2.0 and 100Ω ± 15% (for HDMI) ( 85Ω to 115Ω). That is, even in the common mode noise filter arranged on this transmission line, if the characteristic impedance is within the above-mentioned specified range, signal reflection and loss are small, and signal deterioration can be prevented. The characteristic impedance is proportional to √ (L / C) (L is the inductance value of the coil per unit length of the transmission line, and C is the capacitance between the coils per unit length). When the stray capacitance between them is large, the characteristic impedance may decrease and become lower than the specified range. On the other hand, in the present invention, the line widths of the second and fourth spiral conductors 13 and 16 are made narrower than the line widths of the first and third spiral conductors 12 and 15, and the second spiral conductor 13. Is reduced between the second spiral conductor 13 and the third spiral conductor 15 (between the first coil 14 and the second coil 17). The first coil 14 and the second coil 17 are each reduced by narrowing the line width of each of the first coil 14 and the second coil 17 at the same time. The inductance value is increased. That is, the characteristic impedance is increased by decreasing C and increasing L.

  In the above configuration, the line widths of the second and fourth spiral conductors 13 and 16 are narrower than the line widths of the first and third spiral conductors 12 and 15. This means that the line widths of only the second and fourth spiral conductors 13 and 16 are changed to be thinner than when the line widths of the spiral conductors 12, 13, 15, and 16 are substantially the same. Therefore, if the line widths of only the second and fourth spiral conductors 13 and 16 are narrowed, the line widths of the first to fourth spiral conductors 12, 13, 15, and 16 are all substantially the same. The facing area between the second spiral conductor 13 and the third spiral conductor 15 is reduced, and the stray capacitance can be reduced.

  At this time, not only the second and fourth spiral conductors 13 and 16 but also the first and third spiral conductors 12 and 15 may be thinned. In this case, one of the first spiral conductor 12 and the second spiral conductor 13 constituting the first coil 14, and the third spiral conductor 15 and the fourth spiral constituting the second coil 17. The line width of one of the conductors 16 is reduced. This is because it is necessary to match the impedance and DC resistance value of the first coil 14 with the impedance and DC resistance value of the second coil 17.

In the first embodiment of the present invention, the dielectric constant of the insulator layer 11c between the third spiral conductor 15 and the second spiral conductor 13 is made lower than the dielectric constant of the other insulator layers. Second
Since the stray capacitance between the spiral conductor 13 and the third spiral conductor 15 can be reduced, the characteristic impedance can be prevented from being lowered by the stray capacitance, and the specified characteristic impedance can be obtained more reliably.

(Embodiment 2 )

  FIG. 4 is an exploded perspective view of the common mode noise filter according to Embodiment 2 of the present invention. In the second embodiment of the present invention, components having the same configurations as those of the first embodiment of the present invention are denoted by the same reference numerals, and the description thereof is omitted.

  The difference between the second embodiment of the present invention and the first embodiment of the present invention is that the distance between the second spiral conductor 13 and the third spiral conductor 15 is as shown in FIG. This is a point that is larger than the distance between the first spiral conductor 12 and the third spiral conductor 15 and the distance between the second spiral conductor 13 and the fourth spiral conductor 16.

  At this time, at least the thicknesses of the second to fourth insulator layers 11b to 11d are made substantially the same, and the third insulator layer 11c between the second spiral conductor 13 and the third spiral conductor 15 is formed. The number of the second insulator layers 11b between the first spiral conductor 12 and the third spiral conductor 15 and between the second spiral conductor 13 and the fourth spiral conductor 16 are the same. The number of the fourth insulator layers 11d is larger.

  Further, the thickness of the third insulator layer 11c is made larger than the thickness of the second and fourth insulator layers 11b and 11d, and the distance between the second spiral conductor 13 and the third spiral conductor 15 is set. May be larger than the distance between the first spiral conductor 12 and the third spiral conductor 15 and the distance between the second spiral conductor 13 and the fourth spiral conductor 16.

  In the second embodiment, the line widths of the first to fourth spiral conductors 12, 13, 15, and 16 are not necessarily different.

  In the second embodiment of the present invention, the same equivalent circuit as the circuit shown in FIG. 3 is obtained, and the common mode noise entering from the first external electrode 22 and the third external electrode 24 is reduced to the first. The first spiral conductor 12 and the third spiral conductor 15 are magnetically coupled, and the second spiral conductor 13 and the fourth spiral conductor 16 are magnetically coupled, so that common mode noise can be removed.

  FIG. 5 shows the positional relationship of the spiral conductors in the stacking direction in the equivalent circuit according to Embodiment 2 of the present invention.

  In the second embodiment described above, as shown in FIGS. 4 and 5, the distance D between the second spiral conductor 13 and the third spiral conductor 15 is set to the first spiral conductor 12 and the third spiral conductor 15. The distance between the second spiral conductor 13 and the third spiral conductor 15 is larger than the distance d2 between the second spiral conductor 13 and the fourth spiral conductor 16. Since the space between the spiral conductor 15 can be widened, and the stray capacitance between the second spiral conductor 13 and the third spiral conductor 15 can be reduced thereby, the stray capacitance reduces the characteristic impedance. It is possible to prevent this, and the effect that a specified characteristic impedance can be obtained is obtained.

Further, since the distance between the first spiral conductor 12 and the third spiral conductor 15 and the distance between the second spiral conductor 13 and the fourth spiral conductor 16 can be reduced, the first spiral conductor 12 can be reduced. The magnetic coupling between the spiral conductor 12 and the third spiral conductor 15 and the magnetic coupling between the second spiral conductor 13 and the fourth spiral conductor 16 can be strengthened, thereby increasing the number of common modes. Noise can be removed.

(Embodiment 3 )

  FIG. 6 is an exploded perspective view of the common mode noise filter according to Embodiment 3 of the present invention. In the third embodiment of the present invention, components having the same configurations as those of the first embodiment of the present invention are denoted by the same reference numerals, and the description thereof is omitted.

  The third embodiment of the present invention is different from the first embodiment of the present invention described above in that a spiral conductor and a second coil 17 constituting the first coil 14 are constituted as shown in FIG. Instead of alternately laminating the spiral conductors, a third coil 17 is formed between the first spiral conductor 12 and the second spiral conductor 13 constituting the first coil 14. The spiral conductor 15 and the fourth spiral conductor 16 are stacked.

  At this time, the first spiral conductor 12 and the second spiral conductor 13 include the three first via electrodes 18 formed in the second insulator layer 11b to the fourth insulator layer 11d, respectively. And the first coil 14 is configured. Further, the third spiral conductor 15 and the fourth spiral conductor 16 are connected to each other via one second via electrode 19 formed in the third insulator layer 11c, and the second coil. 17 is constituted.

  In the third embodiment, the line widths of the first to fourth spiral conductors 12, 13, 15, and 16 are not necessarily different.

  In the third embodiment of the present invention, the same equivalent circuit as the circuit shown in FIG. 3 is obtained, and the common mode noise entering from the first external electrode 22 and the third external electrode 24 is reduced to the first level. The first spiral conductor 12 and the third spiral conductor 15 are magnetically coupled, and the second spiral conductor 13 and the fourth spiral conductor 16 are magnetically coupled, so that common mode noise can be removed.

  FIG. 7 shows the positional relationship in the stacking direction of each spiral conductor in the equivalent circuit according to Embodiment 3 of the present invention.

  In the above-described third embodiment, as shown in FIG. 7, the third spiral conductor 15 and the fourth spiral conductor 16 that are adjacent to each other in the stacking direction constitute the same coil 17. Since these adjacent spiral conductors 15 and 16 are at the same potential, and no stray capacitance is generated between the spiral conductors 15 and 16 adjacent in the stacking direction, it is possible to prevent the characteristic impedance from being lowered by the stray capacitance. The effect of obtaining a specified characteristic impedance is obtained.

  FIG. 8 is a diagram comparing characteristic impedances of the common mode noise filter according to Embodiment 3 of the present invention and a conventional common mode noise filter. Note that USB 2.0 is used as the transmission line, and the specified value of the characteristic impedance is 90Ω ± 15%.

  As is apparent from FIG. 8, the characteristic impedance of the present invention is higher than the conventional characteristic impedance, and the frequency characteristic of the transmission signal generally used may be out of the specified value at the frequency of 100 MHz to 1 GHz. However, it can be seen that the characteristic impedance of the present invention does not deviate from the specified value.

  Further, as shown in FIG. 9, the sixth insulator layer 20 provided below the first spiral conductor 12 and the second spiral conductor 13, and the third spiral conductor 15 and the second spiral conductor 15 The third insulator layer 11c, the first insulator layer 11a, and the fifth insulator layer 11e provided between the four spiral conductors 16 are made of a magnetic material, and the other insulator layer 11b. , 11d are made of a non-magnetic material, the first spiral conductor 12 and the third spiral conductor 15 that are magnetically coupled, and the second spiral conductor 13 and the fourth spiral conductor 16 are connected to each other. Since the gap is made of a non-magnetic material and the upper and lower sides can be made of a magnetic material, the common mode impedance can be increased, thereby removing a lot of common mode noise.

  As shown in FIG. 9, in the second and fourth insulator layers 11b and 11d made of a nonmagnetic material, the magnetic material is placed inside the spirals of the second and third spiral conductors 13 and 15, respectively. The magnetic portions 26 may be provided so as to be at the same position in a top view. Thereby, since the magnetic field which cross | intersects between the 1st coil 14 and the 2nd coil 17 can be strengthened, the impedance of the common mode component of the 1st coil 14 and the 2nd coil 17 can be enlarged. .

  And the magnetic part 26 carries out a drilling process with the laser in the predetermined location of the 2nd, 4th insulator layers 11b and 11d, and filled this hole with magnetic materials, such as Ni-Cu-Zn ferrite. Form. The first via electrode 18, the second via electrode 19, and the magnetic part 26 are prevented from contacting each other when viewed from above.

  At this time, the second insulator layer 11b and the fourth insulator layer 11d are made of the same nonmagnetic material, and the first via electrode 18 and the magnetic portion 26 are formed at the same location. There is no need to manufacture them separately, which can improve productivity. Further, the magnetic part 26 may be formed on an insulator layer made of a nonmagnetic material of the common mode noise filter shown in FIG. The magnetic part 26 is disposed so as to be sandwiched between the first via electrode 18 and the second via electrode 19 in a top view.

  In the first to third embodiments of the present invention described above, the first coil 14 and the second coil 17 are provided, but two or more may be provided as an array type. .

  Moreover, although the two spiral conductors constituting each of the first and second coils 14 and 17 have been described, and the four spiral conductors are laminated, the first and second coils 14 and 17 are respectively provided. Three or more spiral conductors may be configured, and six or more spiral conductors may be stacked. Also in this case, if the same configuration as in the first to third embodiments is employed, an effect that a specified characteristic impedance can be obtained can be obtained.

  The common mode noise filter according to the present invention has an effect that a specified characteristic impedance can be obtained, and in particular, common mode noise used as a noise countermeasure for various electronic devices such as digital devices, AV devices, and information communication terminals. This is useful in filters and the like.

11a-11e 1st-5th insulator layer 12 1st spiral conductor 13 2nd spiral conductor 14 1st coil 15 3rd spiral conductor 16 4th spiral conductor 17 2nd coil 20 Sixth insulator layer

Claims (2)

A plurality of insulator layers; a first coil comprising a first spiral conductor and a second spiral conductor formed on the insulator layer; and a third spiral conductor formed on the insulator layer. And a second coil composed of a fourth spiral conductor, and the first spiral conductor, the third spiral conductor, the second spiral conductor, and the fourth spiral conductor are stacked in this order. The insulator layer thicker than the other insulator layer is disposed between the second spiral conductor and the third spiral conductor, and the second spiral conductor and the third spiral conductor are disposed. The distance from the third spiral conductor is determined from the distance between the first spiral conductor and the third spiral conductor, and the distance between the second spiral conductor and the fourth spiral conductor. The plurality of insulator layers are made of ferrite or glass ceramic. And, the first, the more the line width of the third spiral conductor second, common mode noise filter as the line width of the fourth spiral conductor is thin. A plurality of insulator layers; a first coil comprising a first spiral conductor and a second spiral conductor formed on the insulator layer; and a third spiral conductor formed on the insulator layer. And a second coil composed of a fourth spiral conductor, and the first spiral conductor, the third spiral conductor, the second spiral conductor, the fourth spiral conductor are laminated in this order, or The third spiral conductor constituting the second coil and the fourth spiral between the first spiral conductor constituting the first coil and the second spiral conductor constituting the first coil. And the first spiral conductor and the second spiral conductor are connected via a first via electrode, and the third spiral conductor and the fourth spiral conductor are The second and third spiral conductors are connected via a second via electrode; A magnetic part made of a magnetic material is formed inside the winding so that the first via electrode, the second via electrode and the magnetic part do not contact each other in a top view, and further, the magnetic part in a top view. Is a common mode noise filter disposed so as to be sandwiched between the first via electrode and the second via electrode.