JP2009171501A - Noise suppression component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise suppression component capable of securely suppressing both common mode currents of a first order common mode and a second order common mode. <P>SOLUTION: The component includes common mode choke coil units 10, 20, 30, an insulator 4, magnetic body substrates 51, 52, and an external electrodes 6-1 to 6-8. The coil unit 10 (20, 30) has a coil 11 (21, 31) and a coil 12 (22, 32). End portions 11a, 12a of the coils 11, 12 of the coil unit 10 are connected to the external electrodes 6-1, 6-2. End portions 21a, 21b of the coil 21 of the coil unit 20 are connected to the external electrodes 6-3, 6-7. End portions 22a, 22b of the coil 22 are connected to an end portion 11b of the coil 11 and the external electrode 6-5. End portions 31a, 31b of the coil 31 of the coil unit 30 are connected to the external electrodes 6-4, 6-8. End portions 32a, 32b of the coil 32 are connected to an end portion 12b of the coil 12 and the external electrode 6-6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a noise countermeasure component in which a plurality of noise removal circuits such as a common mode choke coil are accommodated in one chip to reduce the mounting area.

Conventionally, as this type of noise countermeasure component, for example, there is a technique disclosed in Patent Document 1.
This noise countermeasure component includes a common mode choke coil portion inserted into a pair of differential transmission lines, and ferrite beads inserted into a power supply / ground line.
As a result, when a differential signal in the reverse direction is input from the differential transmission line to the common mode choke coil portion, it is allowed to pass smoothly without being attenuated. Thus, the case where the current in the reverse direction flows through the pair of differential transmission lines is hereinafter referred to as “differential mode”.
When a common mode current in the same direction enters a pair of differential transmission lines and a current opposite to the current flows in the ground line, the common mode choke coil functions and the common mode The current is attenuated. A case where a current in the same direction flows in a pair of differential transmission lines and a current in the opposite direction to the current flows in the ground line is hereinafter referred to as a “primary common mode”.
However, if common-mode current in the same direction flows not only in a pair of differential transmission lines but also in the ground line, these common-mode currents cannot be attenuated and noise may be radiated from the transmission cable. There is. Thus, the case where the current in the same direction flows not only in the pair of differential transmission lines but also in the ground line is hereinafter referred to as “secondary common mode”.
As a noise countermeasure component capable of attenuating such secondary common mode current, for example, there is a technique disclosed in Patent Document 2.
FIG. 20 is a circuit diagram showing an example of a prior art capable of attenuating a secondary common mode current, and FIG. 21 is a circuit diagram for explaining the operation of the prior art.
As shown in FIG. 20, the component 100 has a configuration including four coils 101 to 104 that are close to each other. The component 100 is mounted on a transmission cable 120 that connects the transceiver 110 and the receiver 111. Specifically, the coils 101 and 104 of the component 100 are connected to the ground lines 121 and 124 of the transmission cable 120, respectively, and the coils 102 and 103 are connected to the differential transmission lines 122 and 123, respectively.
As a result, as shown in FIG. 21, four common mode currents I in the same direction flow in the coils 101 to 104, and a reverse current -I flows in the set ground 130 such as the chassis to enter the secondary common mode. Then, since the current I flowing through the coils 101 to 104 is in the same direction, the magnetic flux h of each current I is added to increase the combined magnetic flux H. As a result, the impedance of the component 100 increases, and the four common mode currents I are attenuated by the component 100.

JP 2005-302810 A JP 2006-191006 A

However, the conventional noise countermeasure component shown in FIG. 20 has the following problems.
FIG. 22 is a circuit diagram for explaining the problems of the prior art.
In the primary common mode, as shown in FIG. 22, the common mode current I in the same direction flows in the coils 102 and 103 of the component 100, and the reverse current −I flows in the coils 101 and 104. In such a primary common mode state, the current I flowing through the coils 101 and 102 is in the reverse direction. For these coils 101 and 102, the differential mode state is maintained, and the current I flowing through the coils 103 and 104 is also in the reverse direction. Similarly, it is necessary to maintain a differential state for these coils 103 and 104 as well.
However, in the conventional component 100, the electromagnetic coupling degree of the four adjacent coils 101 to 104 is very high. For this reason, the magnetic field leaking from the coils 101 and 102 (or the coils 103 and 104) crosstalks with the coils 101 and 102 (or the coils 103 and 104), and the differential mode is applied to the coils 101 and 102 (or the coils 103 and 104). A current different from the currents I and I is induced, the differential mode of the coils 101 and 102 (or the coils 103 and 104) is impaired, and radiation noise due to the induced current may be generated.

  The present invention has been made to solve the above-described problems, and provides a noise countermeasure component capable of reliably removing both a primary common mode common mode current and a secondary common mode common mode current. With the goal.

In order to solve the above-mentioned problems, the invention of claim 1 is characterized in that first to third common mode choke coil portions each having a first coil and a second coil which are arranged opposite to each other and can be magnetically coupled to each other. One insulator including these first to third common mode choke coil portions, and first to fourth external electrodes provided on the outer surface of the insulator and used as input side terminals or output side terminals And, on the outer surface of the insulator, contrary to the first to fourth external electrodes, a noise countermeasure component comprising fifth to eighth external electrodes used as output side terminals or input side terminals. The one end of the first coil of the first common mode choke coil is connected to the first external electrode, and the one end of the second coil is connected to the second external electrode. And the second One end portion and the other end portion of the first coil of the non-mode choke coil portion are connected to the third external electrode and the seventh external electrode, respectively, and the one end portion and the other end portion of the second coil. Are respectively connected to the other end portion of the first coil of the first common mode choke coil portion and the fifth external electrode, and one end portion and the other end of the first coil of the third common mode choke coil portion. Are connected to the fourth external electrode and the eighth external electrode, respectively, and one end and the other end of the second coil are connected to the other of the second coils of the first common mode choke coil portion. It was set as the structure connected to the edge part and the 6th external electrode, respectively.
With this configuration, the first and second external electrodes can be connected to, for example, the input side of the pair of differential transmission lines, and the fifth and sixth external electrodes can be connected to the output side. In addition, the third and fourth external electrodes can be connected to, for example, the input side of a pair of ground lines, and the seventh and eighth external electrodes can be connected to the output side.
In this state, when a pair of differential signals in opposite directions is input to the first and second external electrodes through a pair of differential transmission lines, the differential mode is set.
In such a mode, the current of one differential signal input from the first external electrode flows from the first coil of the first common mode choke coil section to the second coil of the second common mode choke coil section. And output to the differential transmission line through the fifth external electrode. On the other hand, the current of the other differential signal is in the opposite direction to the one current, and the first common mode choke coil section passes through the second coil of the third common mode choke coil section from the sixth external electrode. It flows through the second coil and is output to the differential transmission line through the second external electrode. Therefore, in the first common mode choke coil portion, the current of the pair of differential signals flows in the opposite directions through the first coil and the second coil, so that the magnetic fluxes cancel each other. Further, in each of the second and third common mode choke coil sections, each current flows only through one of the second coils. Therefore, the magnetic flux generated by the current flowing through the second coil of the second and third common mode choke coil sections. There is no increase. As a result, there is no increase in impedance of the entire component, and a pair of differential signals flows smoothly in the component.
By the way, a pair of common-mode currents in the same direction flow through a pair of differential transmission lines and are input to the first and second external electrodes, and a pair of currents in directions opposite to those common-mode currents. However, it may flow through a pair of ground lines and enter the seventh and eighth external electrodes to enter the primary common mode.
In such a mode, a pair of common mode currents flow in the same direction in the first and second coils of the first common mode choke coil section, so that the magnetic flux is strengthened and the impedance of this portion increases. As a result, the common mode current in the same direction flowing through the pair of differential transmission lines and input to the first and second external electrodes is attenuated by the first common mode choke coil section. At this time, a pair of currents in opposite directions flow through the first coils of the second and third common mode choke coils, and the influence of the magnetic flux due to these currents is influenced by the second and third common mode choke coils. This is applied only to the magnetic flux generated in the second coil of the first portion, and does not affect the magnetic flux generated in the first and second coils of the first common mode choke coil portion.
In addition, a pair of currents in the same direction flows through the pair of differential transmission lines and is input to the first and second external electrodes. Further, a pair of currents in the same direction as these currents is 1 There is a case in which the current flows in a pair of ground lines and is input to the third and fourth external electrodes, and a current in a direction opposite to the two pairs of currents flows to a set ground such as a chassis to enter a secondary common mode. .
In this mode, the current from the first external electrode flows through the first coil of the first common mode choke coil portion to the second coil of the second common mode choke coil portion, and the third external electrode. Current flows through the first coil of the second common mode choke coil section and is a common mode current in the same direction, so that the magnetic fluxes are strengthened and the impedance of this portion increases. As a result, the common mode current in the same direction input to the first and third external electrodes is attenuated by the second common mode choke coil section. On the other hand, the current from the second external electrode flows to the second coil of the third common mode choke coil section through the second coil of the first common mode choke coil section, and from the fourth external electrode. Current flows through the first coil of the third common mode choke coil section. Also in this case, since the common mode current in the same direction flows through the first and second coils of the third common mode choke coil portion, the magnetic fluxes are strengthened with each other, and the impedance of this portion increases. As a result, the common mode current in the same direction input to the second and fourth external electrodes is attenuated by the third common mode choke coil section.

According to a second aspect of the present invention, there is provided the noise countermeasure component according to the first aspect, wherein the first to third common mode choke coil portions are not magnetically affected by each other. The choke coil portion is included in the insulator in a state where the choke coil portion is separated by a predetermined distance.
With this configuration, it is possible to reduce crosstalk between the first to third common mode choke coil portions, and thus it is possible to suppress unnecessary common mode current generated due to magnetic flux wraparound.

According to a third aspect of the present invention, in the noise countermeasure component according to the first or second aspect, a wide electrode portion is provided at one end portion of the first coil in the second common mode choke coil portion, and the electrode portion Is placed close to the first coil in the first common mode choke coil portion to form a first capacitor portion, and a wide width is formed at one end of the first coil in the third common mode choke coil portion. An electrode portion is provided, and the second capacitor portion is formed by bringing the electrode portion close to the second coil in the first common mode choke coil portion.
With this configuration, in the primary common mode, a potential difference is generated between one end portion of the first coil in the first common mode choke coil portion and one end portion of the first coil in the second common mode choke coil portion. And a potential difference is generated between one end of the second coil in the first common mode choke coil portion and one end of the first coil in the third common mode choke coil portion. A pair of common mode currents that cannot be removed by the common mode choke coil portions of the second and third common mode choke coil portions from the first common mode choke coil portion through the first and second capacitor portions. It flows to one end of one coil and flows out to a pair of ground lines through the third and fourth external electrodes.
In the secondary common mode, there is no potential difference between both ends of the first and second capacitor sections, so that the current input from the first and second external electrodes is second from the first common mode choke coil section. And it does not flow to the first coil side of the third common mode choke coil section.

  As described above in detail, according to the noise countermeasure component of the present invention, in the differential mode, a pair of differential signals can pass smoothly, and in the primary common mode, the common mode current is In the case of the secondary common mode, the common mode current can be attenuated by the second and third common mode choke coils, respectively. There is an excellent effect that both the mode current and the secondary common mode common mode current can be surely removed. In addition, since all modes can be handled with one chip, the mounting area can be reduced.

  In particular, according to the invention of claim 2, the common mode current removal effect in the primary and secondary common modes can be further enhanced.

  According to the invention of claim 3, the common mode current removal effect in the primary common mode can be further enhanced.

  The best mode of the present invention will be described below with reference to the drawings.

  FIG. 1 is an exploded perspective view of a noise countermeasure component according to the first embodiment of the present invention, and FIG. 2 is a perspective view of the noise countermeasure component shown through the inside.

  As shown in FIGS. 1 and 2, the noise countermeasure component 1 of this embodiment includes three common mode choke coil portions 10, 20, and 30 as first to third common mode choke coil portions, A rectangular parallelepiped insulator 4 including the common mode choke coil portions 10, 20, and 30, a pair of magnetic substrates 51 and 52 sandwiching the insulator 4 from above and below, and first to eighth external electrodes Eight external electrodes 6-1 to 6-8 are provided.

FIG. 3 is a schematic equivalent circuit diagram of the noise countermeasure component 1.
Here, the electrical structure of the noise countermeasure component 1 will be described with reference to FIG.
As shown in FIG. 3, the common mode choke coil unit 10 includes a coil 11 as a first coil and a coil 12 as a second coil, and the coils 11 and 12 are arranged to face each other when energized. Magnetically coupled.
Similarly, the common mode choke coil portion 20 (30) also includes a coil 21 (31) as a first coil and a coil 22 (32) as a second coil which are arranged opposite to each other and can be magnetically coupled to each other. Yes.

The external electrodes 6-1 to 6-8 are electrodes for soldering the noise countermeasure component 1 such as a transmission cable or a land on a substrate.
As shown in FIG. 2, the external electrodes 6-1 to 6-4 are arranged on one outer surface 4a of the insulator 4, and are used as an input side terminal or an output side terminal. On the other hand, the external electrodes 6-5 to 6-8 are arranged in a row on the outer surface 4b opposite to the outer surface 4a, and these external electrodes 6-5 to 6-8 are external electrodes 6-1 to 6-8. Contrary to 4, it is used as an output side terminal or an input side terminal.

  As shown in FIG. 3, one end 11a of the coil 11 of the common mode choke coil 10 is connected to the external electrode 6-1 and one end 12a of the coil 12 is connected to the external electrode 6-2. Has been. Further, one end 21a and the other end 21b of the coil 21 of the common mode choke coil section 20 are connected to the external electrode 6-3 and the external electrode 6-7, respectively. One end 22a of the coil 22 is connected to the other end 11b of the coil 11 of the common mode choke coil unit 10, and the other end 22b is connected to the external electrode 6-5. Also, one end 31a and the other end 31b of the coil 31 of the common mode choke coil section 30 are connected to the external electrode 6-4 and the external electrode 6-8, respectively. One end portion 32a of the coil 32 is connected to the other end portion 12b of the coil 12 of the common mode choke coil portion 10, and the other end portion 32b is connected to the external electrode 6-6.

The noise countermeasure component 1 having such an electrical structure is a multilayer chip component. That is, as shown in FIG. 1, the insulator 4 is composed of insulating layers 41 to 45, and conductor patterns of the common choke coil portions 10, 20, and 30 are formed on the insulating layers 41 to 45. 41 to 45 are stacked on the magnetic substrate 51, and the magnetic substrate 52 is bonded to the uppermost layer.
4 is a plan view showing a pattern of the first layer, FIG. 5 is a plan view showing a pattern of the second layer, FIG. 6 is a plan view showing a pattern of the third layer, and FIG. These are top views which show the pattern of the 4th layer.
Specifically, as shown in FIGS. 1 and 4, a first insulating layer 41 is provided on the magnetic substrate 51, and one end portions 21 a and 12 a and this coil 32 are conductors on the insulating layer 41. The pattern is formed.
1 and 5, the second insulating layer 42 is laminated on the insulating layer 41 including the coil 32 and the like, and the coils 12 and 21 are patterned on the insulating layer 42 with a conductor. Yes. At this time, via holes 42a and 42b are provided at the lower end and the inner end of the other end 12b of the coil 12, and the other end 12b and the inner end of the lower coil 32 are connected through the via hole 42a. 12 is connected to the one end 12a through a via hole 42b. A via hole 42c is also provided at the inner end of the coil 21, and the inner end and the lower end portion 21a are connected to each other through the via hole 42c.
Further, as shown in FIGS. 1 and 6, a third insulating layer 43 is laminated on the insulating layer 42, and the coils 11 and 31 are patterned on the insulating layer 43 with a conductor.
As shown in FIGS. 1 and 7, a fourth insulating layer 44 is laminated on the insulating layer 43, and the coil 22 and one end portions 11a and 31 are patterned on the insulating layer 44 with a conductor. ing. At this time, the via holes 44a and 44b are provided below the tips of the one end portions 11a and 31a, the one end portion 11a and the inner end of the lower coil 11 are connected through the via hole 44a, and the one end portion 31a and the coil are connected. The inner end of 31 is connected through a via hole 44b. A via hole 44c is also provided at the inner end of the coil 22, and the inner end is connected to the other end 11b of the lower layer coil 11 through the via hole 44c.
An insulating layer 45 is laminated on the insulating layer 44 so as to cover the coil 22 and the one end portions 11 a and 31, and the magnetic substrate 52 is bonded onto the insulating layer 45 by an adhesive layer 53.

FIG. 8 is a transmission plan view showing the arrangement of the common mode choke coil portions 10, 20, and 30. For ease of understanding, in FIG. 8, the conductor pattern formed on the fourth insulating layer 44 is indicated by a black line, and the conductor pattern formed on the third insulating layer 43. The conductor pattern formed on the second insulating layer 42 is indicated by a two-dot chain line, and the conductor pattern formed on the first insulating layer 41 is indicated by a broken line. It was.
In the noise countermeasure component 1 having a structure as a multilayer chip component as described above, as shown in FIG. 8, the common mode choke coil portions 10, 20, 30 are separated from each other by a predetermined distance in the insulator 4. Formed. Specifically, the common mode choke coil portions 10, 20, and 30 are arranged so as to be positioned at the vertices of a virtual triangle so that they are not affected by magnetic influences.

A method of manufacturing the noise countermeasure component 1 having such a structure will be briefly described.
As shown in FIGS. 1 and 4 to 7, first, the insulating layer 41 is formed on the magnetic substrate 51 by exposing and developing by a photolithography method.
In this embodiment, the magnetic substrates 51 and 52 are used as the substrates, but it goes without saying that a dielectric substrate or an insulating substrate may be used depending on the application of the component. Further, the surface roughness Ra of the magnetic substrate 51 is set to 0.5 μm or less so as not to hinder the formation of the insulating layers 41 to 45 and the coils 11 to 31 and 12 to 32 formed by the subsequent photolithography method. It is desirable to polish.
As the insulating layers 41 to 44, any of various resin materials such as polyimide resin, epoxy resin, and benzocyclobutene resin, glass such as SiO2, glass ceramics, dielectrics, and the like can be used. In this embodiment, a photosensitive polyimide resin is used as the material for the insulating layers 41 to 45.
Thereafter, a conductor film is formed on the insulating layer 41 by using a thin film forming method such as sputtering or vapor deposition or a film forming technique such as screen printing, and a series of photolithography such as resist coating, exposure, development and etching. The one end portions 12a and 21a and the coil 32 are patterned using a technique.
As a material for the conductor film, it is desirable to use a metal such as Ag, Pd, Cu and Al having excellent conductivity, or an alloy of these metals. In this embodiment, Ag is used as the material for the conductor film.
Next, after the insulating layer 42 having holes for the via holes 42a to 42c is laminated on the insulating layer 41 so as to cover the one end portions 12a and 21a and the coil 32 by using a photolithography method, the same as described above. , Ag conductor film is formed on the insulating layer 42, and the coils 12 and 21 are patterned using a series of photolithography techniques such as resist coating, exposure, development and etching. Thereby, the coil 12 and the coil 32 are electrically connected through the via holes 42a and 42b, and the coil 21 and the one end 21a are electrically connected through the via hole 42c.
Thereafter, the insulating layer 43 in which the coils 11 and 31 are formed and the insulating layer 44 in which the one end portions 11a and 31a and the coil 22 are formed are stacked in the same manner as described above, and the insulating layer 45 is stacked on the uppermost layer. To do.

Then, the adhesive layer 53 is applied and formed on the lower surface of the magnetic substrate 52, and the magnetic substrate 52 is bonded onto the insulating layer 45.
The joining of the magnetic substrate 52 is realized by a process of heating and pressurizing in vacuum or inert gas, cooling, and releasing the pressure.
Here, in this embodiment, a thermosetting polyimide resin is used as the material of the adhesive layer 53. However, when the noise countermeasure component 1 is reflow-mounted, it is heated to around 260 °, so that it is desirable to use a glass transition temperature of 270 ° C. or higher for the material of the adhesive layer 53. Further, when the magnetic substrate 52 is bonded, a high temperature of 350 ° C. to 390 ° C. is applied, and the magnetic substrate 52 is thermocompression bonded to the insulating layer 45. If the gas flows out of the material at this high temperature, pores are formed in the adhesive layer 53. This hole causes a decrease in adhesion. Moreover, when moisture accumulates in the holes, it causes a short circuit of the coils 11 to 31 and 12 to 32 and the like. For this reason, it is desirable to use the adhesive layer 53 having a heat resistant temperature of 400 ° C. or higher.

After the substrate bonding process as described above, the chip of the noise countermeasure component 1 is cut out from the mother substrate by cutting such as dicing and divided, and external electrodes 6 to be connected to the internal coils 11 to 31 and 12 to 32 are connected. 1 to 6-8 are formed on the chip side surface of each noise countermeasure component 1.
The external electrodes 6-1 to 6-8 are formed by, for example, applying a conductive paste containing Ag, Ab-Pd, Cu, NiCr or NiCu, or forming these metals by sputtering or vapor deposition. Thereafter, a metal film such as Ni, Sn, Sn-Pb or the like is formed on the surface by wet electrolytic plating or the like. In this way, the noise countermeasure component 1 can be manufactured.

Next, operations and effects exhibited by the noise countermeasure component of this embodiment will be described.
9 is a perspective view showing a mounted state of the noise countermeasure component 1, FIG. 10 is a schematic equivalent circuit diagram for explaining the operation in the differential mode, and FIG. 11 is the operation in the primary common mode. FIG. 12 is a schematic equivalent circuit diagram for explaining the operation in the secondary common mode.

  As shown in FIG. 9, the external electrodes 6-1 and 6-2 are connected to the input side (the upper line in the drawing) of the pair of differential transmission lines 122 and 123 of the transmission cable 120, and the external electrode 6 −5, 6-6 are connected to the output side, the external electrodes 6-3, 6-4 are connected to the input side of the pair of ground lines 121, 124, and the external electrodes 6-7, 6-8 are output. By connecting to the side, the noise countermeasure component 1 can be mounted on the transmission cable 120. Note that the terms “input side” and “output side” in the transmission cable 120 are used for ease of understanding, and in practice, the “input side” and “output side” of the transmission cable 120 are Of course, the above may be reversed.

In the differential mode, a pair of differential signal currents I and -I flow through the differential transmission lines 122 and 123 as shown in FIG.
In this mode, a differential signal current I input from the differential transmission line 122 through the external electrode 6-1 flows from the coil 11 of the common mode choke coil unit 10 to the coil 22 of the common mode choke coil unit 20. The current I is output to the differential transmission line 122 through the external electrode 6-5. The current -I of one differential signal is in the opposite direction to the current I, and is input from the differential transmission line 123 to the external electrode 6-6, and the common mode choke coil unit through the coil 32 of the common mode choke coil unit 30. 10 coils 12 flow. The current -I is output to the differential transmission line 123 through the external electrode 6-2.
Accordingly, in the differential mode, the currents I and -I of the pair of differential signals flow through the coils 11 and 12 of the common mode choke coil unit 10 in the opposite directions. For this reason, the magnetic flux (illustration omitted) produced around the coil 11 and the coil 12 is reversed and cancels each other.
Further, in the common mode choke coil sections 20 and 30, since the currents I and -I flow only in one of the coils 22 and 32, an increase in magnetic flux due to these currents I and -I does not occur.
Therefore, in the differential mode, since no increase in impedance occurs in the noise countermeasure component 1, the currents I and -I of the pair of differential signals smoothly flow in the noise countermeasure component 1.

In the primary common mode, as shown in FIG. 11, a pair of currents I and I flow through the differential transmission lines 122 and 123, and a pair of currents -I and -I flow through the ground lines 121 and 124. .
In this mode, a pair of common mode currents I and I in the same direction input from the differential transmission lines 122 and 123 through the external electrodes 6-1 and 6-2 cause the coils 11 and 12 of the common mode choke coil unit 10 to pass through. Flowing. At this time, since the magnetic flux generated around the coils 11 and 12 is in the same direction, the magnetic fluxes are strengthened each other. For this reason, the impedance of this portion increases, and these common mode currents I and I are attenuated by the common mode choke coil section 10.
At this time, a pair of currents -I and -I in the opposite direction are input from the ground lines 121 and 124 and flow to the coils 21 and 31 of the common mode choke coil sections 20 and 30. However, since the common mode choke coil unit 10 is separated from the common mode choke coil units 20 and 30 by the predetermined distance, the common mode choke coil unit 10 is supplied to the common mode choke coil unit 10 by the magnetic fluxes of the currents -I and -I flowing through the coils 21 and 31. There is no impact.
Therefore, in the primary common mode, the invading common mode currents I and I are surely attenuated by the common mode choke coil unit 10, and noise radiation due to the common mode currents I and I is generated in the transmission cable 120. There is nothing.

Further, in the secondary common mode, as shown in FIG. 12, two pairs of currents I and I in the same direction flow through the differential transmission lines 121 to 124.
In this mode, the current I input from the differential transmission line 122 through the external electrode 6-1 flows through the coil 11 of the common mode choke coil unit 10 to the coil 22 of the common mode choke coil unit 20. At the same time, the current I input from the ground line 121 through the external electrode 6-3 flows through the coil 21 of the common mode choke coil unit 20. As described above, since the currents I and I flowing through the coils 21 and 22 of the common mode choke coil unit 20 are common mode currents in the same direction, the magnetic fluxes are strengthened with each other, and the impedance of this portion increases. As a result, the common mode currents I and I in the same direction input from the differential transmission line 122 and the ground line 121 through the external electrodes 6-1 and 6-3 are surely attenuated by the common mode choke coil unit 20.
On the other hand, the current I input from the differential transmission line 123 through the external electrode 6-2 flows through the coil 12 of the common mode choke coil unit 10 to the coil 32 of the common mode choke coil unit 30. At the same time, the current I input from the ground line 124 through the external electrode 6-4 flows through the coil 31 of the common mode choke coil unit 30. Also in this case, since the common mode currents I and I in the same direction flow through the coils 31 and 32 of the common mode choke coil section 30, the magnetic fluxes are strengthened and the impedance of this portion increases. As a result, the common mode currents I and I in the same direction input from the differential transmission line 123 and the ground line 124 through the external electrodes 6-2 and 6-4 are reliably attenuated by the common mode choke coil unit 30.
Accordingly, in the secondary common mode, the pair of common mode currents I and I that have entered from the lines 121 and 122 are attenuated by the common mode choke coil unit 20, and the pair of common mode currents I that have entered from the lines 123 and 124. , I are attenuated by the common mode choke coil unit 30, noise radiation due to the common mode currents I, I is not generated in the transmission cable 120.

  As described above, according to the noise countermeasure component 1 of this embodiment, the current of the pair of differential signals smoothly passes in the differential mode, and enters the differential transmission line in the primary common mode. The common mode current is attenuated by the common mode choke coil unit 10 and, in the case of the secondary common mode, the common mode current that has entered from the differential transmission line and the ground line is attenuated by the common mode choke coil units 20 and 30, respectively. Therefore, both the common mode current in the primary common mode and the common mode current in the secondary common mode can be reliably removed. In addition, since all the modes can be handled by the one-chip noise countermeasure component 1, the mounting area can be further reduced.

The inventors conducted the following simple experiment in order to confirm this effect.
FIG. 13 is a circuit configuration diagram of the experiment, and FIG. 14 is a diagram showing a result of the experiment.
In this experiment, three independent common mode choke coils 201 to 203 are mounted on the differential transmission lines 122 and 123 and the ground lines 121 and 124 like the three common mode choke coil portions 10 to 30 of this embodiment. did. The transmission cables 211 to 214 are connected to the output side of the common mode choke coils 202 and 203, the transmission cables 211 and 212 are terminated with a resistor 221, and the transmission cables 213 and 214 are terminated with a resistor 222. In this state, a common mode current I in the same direction is passed through the differential transmission lines 122 and 123 and the ground lines 121 and 124 to obtain a secondary common mode state, and noise N radiated from the transmission cables 211 to 214 was measured. . Then, as shown by the transmittance curve S1 in FIG. 14, the transmittance Ssc12 of the common mode current I was in the vicinity of “−80 dB” in the range of 30 MHz to 1 GHz.
Next, when the common mode choke coils 202 and 203 are not mounted, a common mode current I in the same direction is passed through the differential transmission lines 122 and 123 and the ground lines 121 and 124, and the transmittance Ssc12 is measured. As indicated by the curve S2, it was in the vicinity of “−60 dB” in the range of 30 MHz to 1 GHz.
From this, it was confirmed that noise radiation can be greatly attenuated by mounting the three common mode choke coils 201 to 203 on the differential transmission lines 122 and 123 and the ground lines 121 and 124. . In FIG. 14, a curve S0 indicates the floor level transmittance.

Next explained is the second embodiment of the invention.
FIG. 15 is a schematic equivalent circuit diagram of the noise countermeasure component 1 according to the second embodiment of the present invention, FIG. 16 is an exploded perspective view showing the main part of the noise countermeasure component 1, and FIG. It is a permeation | transmission top view which shows the formation position of.
This embodiment is different from the first embodiment in that a capacitor portion is provided.
That is, as shown in FIG. 15, the capacitor portion 7-1 as the first capacitor portion is connected between one end portion 21 a of the coil 21 in the common mode choke coil portion 20 and the coil 11 in the common mode choke coil portion 10. In addition, the capacitor portion 7-2 as the second capacitor portion is formed between the one end portion 31 a of the coil 31 in the common mode choke coil portion 30 and the coil 12 in the common mode choke coil portion 10.

Specifically, as shown in FIG. 16, a wide electrode portion 71 is formed on one end portion 21a of the first layer, and is placed close to the coil 11 of the third layer. 7-1 is formed between the electrode portion 71 and the coil 11. And the electrode part 72 of the same shape as the electrode part 71 is formed on the one end part 31a of the fourth layer, and is arranged in the state of being close to the coil 12 of the second layer, and the capacitor part 7-2 is placed in the electrode part. 72 and the coil 12.
That is, as shown in FIG. 17, in the state where the noise countermeasure component 1 is viewed from above, the electrode portions 71, so that the electrode portion 71 is adjacent to the coil 11 and the electrode portion 72 is adjacent to the coil 12. 72 is formed.

Next, operations and effects exhibited by the noise countermeasure component of this embodiment will be described.
FIG. 18 is a schematic circuit diagram for explaining the operation of the noise countermeasure component 1 of this embodiment.
In the primary common mode, the distance between the electrode portions 71 and 72 and the coils 11 and 12 and the size of the electrode portions 71 and 72 are changed, and the common mode current N in a high frequency range that cannot be removed by the common mode choke coil portion 10 The capacities of the capacitor units 7-1 and 7-2 are adjusted so that N passes.
In the primary common mode, a potential difference is generated between the external electrodes 6-1 and 6-3 and between the external electrodes 6-2 and 6-4. That is, since a potential difference is generated between both ends of the capacitor portions 7-1 and 7-2, the common mode currents N and N are supplied from the external electrodes 6-1 and 6-2 to the common mode choke coil portion 10 as shown in FIG. When entering the coils 11 and 12, it flows into the one end portions 21a and 31a of the coils 21 and 31 in the common mode choke coil portions 20 and 30 through the capacitor portions 7-1 and 7-2, and the external electrodes 6-3 and 6-3. It flows out to the ground lines 121 and 124 through 6-4.
In the secondary common mode, since no potential difference occurs between both ends of the capacitor parts 7-1 and 7-2, the common mode current input from the external electrodes 6-1 and 6-2 is the capacitor part 7-1. , 7-2.
Since other configurations, operations, and effects are the same as those in the first embodiment, description thereof is omitted.

Next explained is the third embodiment of the invention.
FIG. 19 is an exploded perspective view showing the main part of the noise countermeasure component 1 according to the third embodiment of the present invention.
This embodiment is different from the second embodiment in the formation positions of the electrode portions 71 and 72.
That is, as shown in FIG. 19, one end portion 21a of the coil 21 in the common mode choke coil portion 20 is formed on the third insulating layer 43, and the electrode portion 71 is formed on the one end portion 21a. And adjacent to the coil 11. Thereby, the capacitor portion 7-1 is formed between the adjacent electrode portion 71 and the edge portion of the coil 11. Further, one end 31 a of the coil 31 in the common mode choke coil portion 30 is formed on the second insulating layer 42, and the electrode portion 72 is formed on the one end 31 a so as to be adjacent to the coil 12. It was. Thereby, the capacitor | condenser part 7-2 is formed between the electrode part 72 and the edge part of the coil 12 which adjoin.
Other configurations, operations, and effects are the same as those of the second embodiment, and thus description thereof is omitted.

It is a disassembled perspective view of the noise countermeasure component which concerns on 1st Example of this invention. It is a perspective view of the noise countermeasure component which permeate | transmits and shows an inside. It is a schematic equivalent circuit diagram of a noise countermeasure component. It is a top view which shows the pattern of the 1st layer. It is a top view which shows the pattern of the 2nd layer. It is a top view which shows the pattern of the 3rd layer. It is a top view which shows the pattern of the 4th layer. It is a permeation | transmission top view which shows arrangement | positioning of a common mode choke coil part. It is a perspective view which shows the mounting state of noise countermeasure components. It is a schematic equivalent circuit diagram for demonstrating the effect | action at the time of differential mode. It is a schematic equivalent circuit diagram for demonstrating the effect | action at the time of a primary common mode. It is a schematic equivalent circuit diagram for demonstrating the effect | action at the time of a secondary common mode. It is a circuit block diagram of experiment. It is a diagram which shows the result of experiment. It is a general | schematic equivalent circuit schematic of the noise countermeasure component which concerns on 2nd Example of this invention. It is a disassembled perspective view which shows the principal part of noise countermeasure components. It is a permeation | transmission top view which shows the formation position of a capacitor | condenser part. It is a schematic circuit diagram for demonstrating the effect | action which the noise countermeasure component of this Example shows. It is a disassembled perspective view which shows the principal part of the noise countermeasure component which concerns on 3rd Example of this invention. It is a circuit diagram which shows an example of the prior art which can attenuate the electric current of a secondary common mode. It is a circuit diagram for demonstrating the effect | action of a prior art. It is a circuit diagram for demonstrating the problem of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Noise suppression part, 4 ... Insulator, 4a, 4b ... Outer surface, 6-1 to 6-8 ... External electrode, 7-1, 7-2 ... Capacitor part 10, 20, 30 ... Common mode choke coil 11, 12, 21, 22, 31, 32 ... coil, 11a, 12a, 21a, 22a, 31a, 32a ... one end, 11b, 12b, 21b, 22b, 31b, 32b ... the other end, 41- 45 ... insulating layer, 42 ... insulating layer, 42a-42c, 44a-44c ... via hole, 51, 52 ... magnetic substrate, 53 ... adhesive layer, 71, 72 ... electrode part, I ... current, h, H ... magnetic flux.

Claims (3)

First to third common mode choke coil portions each having a first coil and a second coil which are arranged opposite to each other and can be magnetically coupled to each other, and include these first to third common mode choke coil portions. One insulator, the first to fourth external electrodes provided on the outer surface of the insulator and used as the input-side terminal or the output-side terminal, and the first to fourth external electrodes provided on the outer surface of the insulator. Contrary to the fourth external electrode, a noise countermeasure component comprising fifth to eighth external electrodes used as output side terminals or input side terminals,
One end of the first coil of the first common mode choke coil is connected to the first external electrode, and one end of the second coil is connected to the second external electrode. And
One end portion and the other end portion of the first coil of the second common mode choke coil portion are connected to the third external electrode and the seventh external electrode, respectively, and one end of the second coil. And the other end are connected to the other end of the first coil of the first common mode choke coil and the fifth external electrode, respectively.
One end portion and the other end portion of the first coil of the third common mode choke coil portion are connected to the fourth external electrode and the eighth external electrode, respectively, and one end of the second coil. And the other end portion are connected to the other end portion of the second coil of the first common mode choke coil portion and the sixth external electrode, respectively.
Noise suppression parts characterized by this. In the noise countermeasure component according to claim 1,
The first to third common mode choke coil portions are included in the insulator in a state where they are separated from each other by a predetermined distance so that the first to third common mode choke coil portions are not magnetically affected by each other. The
Noise suppression parts characterized by this. In the noise countermeasure component according to claim 1 or claim 2,
A wide electrode part is provided at one end of the first coil in the second common mode choke coil part, and the electrode part is brought close to the first coil in the first common mode choke coil part. Forming a first capacitor portion;
A wide electrode portion is provided at one end of the first coil in the third common mode choke coil portion, and the electrode portion is brought close to the second coil in the first common mode choke coil portion. The second capacitor part is formed,
Noise suppression parts characterized by this.

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