JP2011004324A - Laminated composite filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce mount area and mounting costs, improve inductance characteristics, reduce residual inductance and design a cancellation capability for common-mode noise.SOLUTION: A laminated composite filter includes a coil part 1a including a common-mode choke coil 10 and a capacitor part 1b including two line-to-ground capacitors 13, 14. In the laminated composite filter, the coil part is configured by laminating a plurality of sheets 6a-6d in which electrode patterns 4a-4c, 5a-5c are formed, and connecting the electrode patterns, and the capacitor part is integrated with the coil part to from one chip and configured by laminating a plurality of sheets 12a-12c in which electrode patterns 11a-11c are formed.

Description

  The present invention relates to a multilayer composite filter that removes, for example, common mode noise generated in a two-wire transmission line.

  In a two-wire transmission line, there is a method using a multilayer composite filter having a common mode choke coil and a line-to-ground capacitor as a method for removing common mode noise generated due to imbalance in communication characteristics between two signal lines (for example, a patent) Reference 1).

  The multilayer composite filter disclosed in Patent Document 1 has a multilayer structure in which a plurality of toroidal ferrite cores and a plurality of electrode plates are alternately stacked. Further, the plurality of electrode plates are provided with lead terminals protruding from one end of the outer periphery thereof. Each lead terminal is alternately arranged to face the opposite side, a plurality of lead terminals protruding on one side are connected to a ground line, and a plurality of lead terminals protruding on the other side are connected to a signal line. The In addition, a coil conductor is wound around the laminate.

  By configuring as described above, a common mode choke coil is formed by generating a magnetic flux with respect to common mode noise and acting as an inductance by a plurality of ferrite cores and coil lead wires, and sandwiches the ferrite core. A line-to-ground capacitor for removing common mode noise by flowing it to the ground is constituted by a plurality of electrode plates provided on both sides of the substrate.

JP 2006-238310 A

  However, the conventional multilayer composite filter disclosed in Patent Document 1 has a structure in which a plurality of toroidal ferrite cores and a plurality of electrode plates are alternately stacked, so that the mounting area is large. As a result, there is a problem that the mounting cost is high. In addition, since the coil conductor is wound around the laminated body, there is a problem in that the stray capacitance between the windings increases and the inductance characteristics deteriorate. Further, when the adhesion between the laminate and the coil conductor is deteriorated, there is a problem that the residual inductance is increased by the coil conductor.

  The present invention has been made to solve the above-described problems. The mounting area is small, the mounting cost can be reduced, the inductance characteristics can be improved, the residual inductance can be reduced, and the common mode noise can be reduced. An object of the present invention is to provide a multilayer composite filter capable of designing a removal capability.

  The multilayer composite filter according to the present invention is a multilayer composite filter including a coil portion having a common mode choke coil and a capacitor portion having two line-to-ground capacitors. The coil portion includes a plurality of sheets on which electrode patterns are formed. In addition, the capacitor part is configured by connecting the electrode pattern, and the capacitor part is formed by stacking a plurality of sheets on which the coil part and the electrode pattern are formed.

  According to the present invention, since it is configured as described above, a coil unit configured by stacking sheets on which electrode patterns are formed, and a capacitor unit configured by stacking sheets on which electrode patterns are formed are provided. By using one chip, the mounting area can be reduced and the mounting cost can be reduced. Also, since no coil lead is used, stray capacitance can be reduced, so that inductance characteristics can be improved, residual inductance can be reduced, and wideband insertion loss against common mode choke noise. Characteristics can be obtained.

1 is a perspective view showing a multilayer composite filter according to Embodiment 1 of the present invention. It is a disassembled perspective view which shows the coil part of the laminated composite filter which concerns on Embodiment 1 of this invention. It is a disassembled perspective view which shows the capacitor | condenser part of the multilayer composite filter which concerns on Embodiment 1 of this invention. It is a figure which shows the equivalent circuit of the laminated composite filter which concerns on Embodiment 1 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Embodiment 1 FIG.
1 is a perspective view showing a multilayer composite filter according to Embodiment 1 of the present invention.
As shown in FIG. 1, the multilayer composite filter includes a rectangular parallelepiped ceramic laminate 1 in which a coil portion 1 a and a capacitor portion 1 b are laminated, and a grounding terminal 2 provided along a central portion of the surface of the ceramic laminate 1. The left and right sides of the ceramic laminate 1 are composed of four signal line terminals 3a to 3d that are provided symmetrically with respect to the ground terminal 2.

  The coil portion 1a of the ceramic laminate 1 is connected to the signal line terminals 3a to 3d, and the capacitor portion 1b of the ceramic laminate 1 is connected to the signal line terminals 3a and 3b and the ground terminal 2.

Next, the structure of the coil part 1a and the capacitor | condenser part 1b of the laminated composite filter comprised as mentioned above is demonstrated.
FIG. 2 is an exploded perspective view showing a coil portion 1a of the multilayer composite filter according to Embodiment 1 of the present invention. FIG. 3 is an exploded perspective view showing capacitor portion 1b of the multilayer composite filter according to Embodiment 1 of the present invention.

  As shown in FIG. 2, the coil portion 1a is connected to the signal line electrode pattern 4a, the signal line terminal 3b, and the signal line electrode pattern 5b connected to the signal line terminal 3a and the signal line electrode pattern 4b. A magnetic sheet 6a having a signal line electrode pattern 5a formed on the surface, and a U-shaped signal line electrode pattern 5b connected to the signal line electrode pattern 5a and the signal line electrode pattern 5c are formed on the surface. A magnetic sheet 6c to be formed; a magnetic sheet 6c on which a U-shaped signal line electrode pattern 4b connected to the signal line electrode pattern 4a and the signal line electrode pattern 4c is formed; and a signal Signal line electrode pattern 4c connected to line terminal 3c and signal line electrode pattern 4b, and signal line electrode pattern 5 connected to signal line terminal 3d and signal line electrode pattern 5b There composed of a ferromagnetic material sheet 6d formed on the surface.

  The magnetic sheets 6a to 6d are, for example, a sheet of slurry raw material prepared by kneading a magnetic material and a binder. Further, the signal line electrode patterns 4a to 4c and 5a to 5c formed on the surfaces of the magnetic sheets 6a to 6d are made of, for example, Ag, Pb, Cu, Au, Ag-Pb, and the like. It is formed by.

  The magnetic sheets 6a to 6d include through holes 7a and signal line electrode patterns 5a to 5c for connecting the signal line electrode patterns 4a to 4c formed on the laminated magnetic sheets 6a to 6d to each other. Each has through-holes 7b for connecting to each other.

As shown in FIG. 2, the magnetic sheets 6 a to 6 d thus formed have a magnetic sheet 6 a on which the signal line electrode patterns 4 a and 5 a are formed on the surface, and a signal line electrode pattern 5 b on the surface. The magnetic sheet 6b, the magnetic sheet 6c on which the signal line electrode pattern 4b is formed, and the magnetic sheet 6d on which the signal line electrode patterns 4c and 5c are formed are laminated in this order.
The signal line electrode pattern 4a of the coil portion 1a is connected to the signal line terminal 3a, the signal line electrode pattern 5a is connected to the signal line terminal 3b, and the signal line electrode pattern 4c is connected to the signal line terminal. The signal line electrode pattern 5c is connected to the signal line terminal 3d. Further, as shown by dotted lines in FIG. 2, the signal line electrode pattern 4a and the signal line electrode pattern 4b, and the signal line electrode pattern 4b and the signal line electrode pattern 4c are connected by a through hole 7a. The electrode pattern 5a and the signal line electrode pattern 5b and the signal line electrode pattern 5b and the signal line electrode pattern 5c are connected by a through hole 7b.

  By configuring the coil portion 1a in this manner, the magnetic sheet 6a on which the signal line electrode pattern 4a is formed on the surface, the magnetic sheet 6c on which the signal line electrode pattern 4b is formed on the surface, and the signal line electrode The first wire-side coil 8 is formed by three layers of the magnetic sheet 6d on which the pattern 4c is formed on the surface, and the magnetic sheet 6a and the signal line electrode pattern 5b on which the signal line electrode pattern 5a is formed. The second wire-side coil 9 is formed of three layers of the magnetic sheet 6b formed on the surface and the magnetic sheet 6d formed on the surface with the signal line electrode pattern 5c. The first line side coil 8 and the second line side coil 9 form a common mode choke coil 10 for removing common mode noise flowing through the two signal lines. Here, the electrode patterns 4a to 4c and 5a to 5c are formed so that the first wire side coil 8 and the second wire side coil 9 are wound in the same direction.

  The inductance of the coil portion 1a is increased by adding three layers of magnetic sheets 6b to 6d as necessary below the four layers of magnetic sheets 6a to 6d shown in FIG. Can do.

  On the other hand, as shown in FIG. 3, the capacitor portion 1b is connected to the dielectric sheet 12a on the surface of which the signal line electrode pattern 11a connected to the signal line terminal 3a is formed and the signal line terminal 3b. The signal line electrode pattern 11b is formed on the surface of the dielectric sheet 12b, and the ground electrode pattern 11c connected to the ground terminal 2 is formed on the surface of the dielectric sheet 12c.

  The dielectric sheets 12a to 12c are formed, for example, by forming a slurry material prepared by kneading a dielectric material and a binder into a sheet shape. The signal line electrode patterns 11a and 11b and the ground electrode pattern 11c formed on the surfaces of the dielectric sheets 12a to 12c are made of, for example, Ag, Pb, Cu, Au, Ag-Pb, and the like. It is formed by the method of.

As shown in FIG. 3, the dielectric sheets 12a to 12c formed in this way are a dielectric sheet 12a on which the signal line electrode pattern 11a is formed on the surface and a dielectric on which the ground electrode pattern 11c is formed on the surface. The body sheet 12c and the signal line electrode pattern 11b are laminated in the order of the dielectric sheet 12b formed on the surface.
The signal line electrode pattern 11a of the capacitor portion 1b is connected to the signal line terminal 3a, the signal line electrode pattern 11b is connected to the signal line terminal 3b, and the ground electrode pattern 11c is connected to the ground terminal 2. Connected.

  By configuring the capacitor portion 1b in this manner, the first line-to-ground capacitor 13 that removes common mode noise flowing through the signal line having the signal line terminal 3a between the signal line terminal 3a and the grounding terminal 2 is provided. The second line-to-ground capacitor 14 is formed between the signal line terminal 3b and the grounding terminal 2 to remove common mode noise flowing through the signal line having the signal line terminal 3b.

  In addition, the capacity | capacitance of the capacitor | condenser part 1b is made to increase by adding four layers which laminated | stacked the dielectric sheet 12c on three layers of the dielectric sheets 12a-12c shown in FIG. 3 as needed. Can do.

  For the exterior for stacking the magnetic sheets 6a to 6d constituting the coil part 1a configured as described above and the dielectric sheets 12a to 12c constituting the capacitor part 1b and further protecting the outermost electrode pattern As shown in FIG. 1, the coil portion 1a and the capacitor portion 1b shown in FIG. 1 are formed into one chip by pressing an insulating sheet having no electrode pattern formed on the surface and pressing it, and then firing it. The multilayer ceramic filter 1 is formed and connected to the signal line terminals 3a to 3d and the grounding terminal 2 to form a multilayer composite filter.

Next, an equivalent circuit of the multilayer composite filter configured as described above will be described.
FIG. 4 is a diagram showing an equivalent circuit of the multilayer composite filter according to Embodiment 1 of the present invention.
As shown in FIG. 4, the equivalent circuit of the multilayer composite filter has a first line-side coil 8 whose both ends are connected to a signal line having signal line terminals 3a and 3c, and signal line terminals 3b and 3d. A common mode choke coil 10 is formed by the second wire side coil 9 whose both ends are connected to the signal line. Also, a first line-to-ground capacitor 13 having one end connected to the signal line having the signal line terminal 3a and the other end connected to the ground line having the grounding terminal 2, and a signal line having the signal line terminal 3b. Is connected to one end, and a second line-to-ground capacitor 14 is formed in which the other end is connected to the ground line having the grounding terminal 2.

  In the common mode choke coil 10, the first line side coil 8 and the second line side coil 9 are wound in the same direction, and therefore the first line side coil 8 and the second line side coil 9 are Electromagnetic coupling in the same direction. Therefore, it is generated due to an unbalance of communication characteristics of two different signal lines connected to the first line side coil 8 and the second line side coil 9, and common mode noise flowing in the same direction with respect to the two signal lines. The common mode noise is removed by generating magnetic flux and acting as an inductance.

  The first line-to-ground capacitor 13 and the second line-to-ground capacitor 14 are connected to the ground via the ground terminal 2 connected to the other end of the common mode noise flowing from the two signal lines connected to the one end. This common mode noise is removed by flowing in

  Thus, the coil portion 1a formed by the magnetic sheets 6a to 6d on which the signal line electrode patterns 4a to 4c and 5a to 5c are formed, the signal line electrode patterns 11a and 11b, and the ground line electrode pattern 11c are formed. Since the capacitor portion 1b formed by the formed dielectric sheets 12a to 12c is laminated, the common mode choke coil 10 for removing common mode noise generated in the two-wire transmission line and two line-to-ground Since a multilayer composite filter in which the capacitors 13 and 14 are integrally molded can be obtained, the mounting area can be reduced and the mounting cost can be reduced.

  Moreover, since the coil part 1b was formed without using the coil conducting wire by laminating the magnetic sheets 6a to 6d on which the signal line electrode patterns 4a to 4c and 5a to 5c are formed, the first Since the potential difference between the line-side coil 8 and the second line-side coil 9 can be reduced, the stray capacitance generated between the first line-side coil 8 and the second line-side coil 9 is reduced. Inductance characteristics can be improved. In addition, by reducing the stray capacitance generated between the first line side coil 8 and the second line side coil 9, the common mode choke coil 10 removes common mode noise well even in the high frequency band. Therefore, the common mode choke coil 10 having a wide-band insertion loss characteristic with respect to common mode noise can be obtained.

  In addition, by configuring the multilayer composite filter without using the coil lead wire, it is possible to reduce the residual inductance that has been generated due to the deterioration of the adhesion between the coil and the laminated body in which the conventional ferrite core and electrode plate are laminated. it can.

  As described above, according to the first embodiment, the coil portion 1a and the signal line are formed by laminating the magnetic sheets 6a to 6c on which the signal line electrode patterns 4a to 4c and 5a to 5c are formed. Since the multilayer composite filter is configured by laminating the capacitor portion 1b formed by laminating the dielectric sheets 12a to 12c on which the electrode patterns 11a and 11b and the ground electrode pattern 11c are formed, the two-wire transmission line Since the common mode choke coil 10 and the two line-to-ground capacitors 13 and 14 for removing the common mode noise conducted to the two can be integrally formed, the mounting area can be reduced and the mounting cost can be reduced. Further, by adopting a configuration that does not use the coil lead wire, the stray capacitance between the windings of the coil can be reduced, so that the inductance characteristics can be improved and the residual inductance can be reduced. Furthermore, the common mode choke coil 10 having a wide band insertion loss characteristic with respect to the common mode noise can be obtained.

  DESCRIPTION OF SYMBOLS 1 Ceramic laminated body, 1a Coil part, 1b Capacitor part, 2 Grounding terminal, 3a-3d Signal line terminal, 4a-4c, 5a-5c Signal line electrode pattern 6a-6d Magnetic sheet, 7a, 7b Through hole , 8 1st wire side coil, 9 2nd wire side coil, 10 common mode choke coil, 11a, 11b electrode pattern for signal line, 11c electrode pattern for grounding, 12a-12c dielectric sheet, 13 first wire Ground capacitor, 14 Second line-to-ground capacitor.

Claims (1)

In a multilayer composite filter including a coil portion having a common mode choke coil and a capacitor portion having two line-to-ground capacitors,
The coil portion is configured by laminating a plurality of sheets on which electrode patterns are formed, and connecting the electrode patterns.
The multilayer composite filter is characterized in that the capacitor unit is formed by stacking a plurality of sheets that are formed into one chip with the coil unit and on which an electrode pattern is formed.

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