JP5425153B2 - Common mode choke coil and adjustment method - Google Patents

Description

  The present invention relates to a technology of a common mode choke coil which is an electronic component used for measures against electromagnetic noise.

In electronic devices and information devices, signals are becoming faster and broadband, and noise countermeasures are difficult and important . In these devices, a common mode choke coil has been widely used as a noise countermeasure. A normal single-ended drive digital signal is likely to emit noise and is also susceptible to external noise . On the other hand, differential transmission is a system in which signal waveforms with opposite polarities are transmitted to both lines, and has a strong characteristic against noise . In high-speed digital devices , differential signal transmission is also widely used in typical interfaces such as USB, LAN, and LVDS.

  However, even in this differential signal transmission, if a phase difference or level difference occurs between the signals of both lines in the transmission signal processing circuit or transmission path, common mode noise that causes noise emission occurs. Further, when the impedance balance around the differential signal circuit is lost, it is affected by external noise such as radiation noise.

  Common mode choke coils are often used as countermeasures against such differential transmission noise, but current common mode choke coils have problems in use.

A typical structure of a common mode choke coil that is commonly used is disclosed in Patent Document 1, for example. The structure shown in Patent Document 1 is shown in FIG. 1A is a front view, FIG. 1B is a side view, and FIG. 1C is a back view. In the structure of the common mode choke coil 10 shown in FIG. 1, wires 13 and 16 are alternately wound around a single magnetic core 11 .

In this type of common mode choke coil 10 , two wires 13 and 16 connected to a signal transmission line are alternately wound around the same magnetic core 11 , and both wire rings formed by the wires 13 and 16 are adjacent to each other. . Thus by way between the line ring of wire 13, 16 magnetic core 11 or from Senwa, a number of electric flux lines generated between Senwa the wire 13 and 16, between the lines wheels of both lines A large stray capacitance is generated. If there is stray capacitance, the waveform of the differential transmission signal to be transmitted is distorted. In particular, when the differential signal used becomes high-speed and the frequency of the transmission signal increases, there is a problem that even if a small stray capacitance is used, the influence becomes large, and the differential signal waveform to be transmitted is greatly distorted, making it unusable for practical use. In a typical conventional common mode choke coil 10 as shown in FIG. 1, when the number of windings of the wire ring is increased, the stray capacitance increases in proportion to the number of windings . Therefore, in the technique described in Patent Document 1, a common mode choke coil having a common mode impedance having a necessary noise countermeasure effect cannot be used.

In order to solve such problems, common mode choke coils with a small stray capacitance have been proposed in, for example, Patent Document 2, Patent Document 3, and Patent Document 4.

Patent Document 2 discloses a common mode choke coil having a structure in which two wire rings are wound around a toroidal core. The structure shown in Patent Document 2 is shown in FIG. However , in the structure of the common mode choke coil 20 shown in FIG. 2, a wire ring (wires 23 and 26) has to be wound in a space surrounded by the core 21, and there is no high-speed winding machine, which is not suitable for mass production. In addition, there is a drawback that it is difficult to provide electrodes for surface mounting.

The structure shown in Patent Document 3 is shown in FIG. The structure of the common mode choke coil 30 shown in FIG. 3 has two U-shaped magnetic cores 31 and 32 on both sides of two wire rings (wires 33 and 36) wound around bobbins 34 and 35. It is inserted from. In this structure, the common mode choke coil 30 itself has a large shape and a high cost.

The structure proposed in Patent Document 4 is shown in FIG. 4A is a front view, FIG. 4B is a side view, and FIG. 4C is a back view. The common mode choke coil 40 shown in FIG. 4 divides the wire rings (wires 43 and 46) of both lines into two magnetic cores 41 and 42, and the distance between the two wire rings is increased. This reduces the stray capacitance generated in the circuit. Two wire rings wound around the pair of electromagnetically symmetrical magnetic cores 41 and 42 so that the winding directions are opposite to each other are formed, and the two wire rings are electromagnetically coupled. Thus, the stray capacitance generated between both lines can be reduced.

FIG. 5 is a diagram for explaining the principle of a conventional common mode choke coil 20. FIG. 5 illustrates the relationship between the current in the common mode choke coil 20 and the magnetic flux in the magnetic core 21. FIG. 5A shows the common mode current and the magnetic flux, and FIG. 5B shows the differential current and the magnetic flux .

In a common mode choke coil used for noise suppression in a signal transmission line, if there is a stray capacitance between the lines, the transmission impedance decreases. Further, if there is an inductance generated by a differential current, there is a problem that the transmission impedance becomes high and the transmission waveform is distorted. Therefore, noise suppression components for signal transmission require a common mode choke coil with a small stray capacitance between transmission lines and a small inductance generated by a differential current.
In an ideal common mode choke coil, for example, as shown in FIG. 5, the magnetic flux generated by the common mode current is added, and the common mode inductance is expanded. On the other hand, the magnetic flux generated by the differential current is canceled out, and no differential inductance is generated. Therefore, there is a function of attenuating common mode noise without attenuating or distorting the differential signal.

JP 2002-246244 A JP 2002-198236 A JP 2004-214334 A JP 2010-153684 A

FIG. 6 is a diagram showing the relationship of the magnetic flux in the coil surrounding space in the conventional common mode choke coil 20. 6A shows the common mode current and magnetic flux, and FIG. 6B shows the differential current and magnetic flux .

Also in the common mode choke coils shown in FIGS. 2, 3, and 4, the magnetic flux generated by the differential current generated in the magnetic core is canceled out, and the differential inductance that affects the differential signal current is generated. do not do. However , in any of the common mode choke coils having the structures shown in FIG. 2, FIG. 3, and FIG. 4, as shown in the example of FIG. 6, the magnetic flux generated in the space around the wire rings is the differential current of both wire wheels. in occurs foot Mr. mating direction, differential inductance increases affect the differential signal current, there is a problem that damage the differential signal current.

  The speed of signal transmission is increasing, and common mode choke coils used for noise countermeasures on differential transmission lines have a small stray capacitance between both transmission lines and a small amount of differential inductance generated by the differential signal current. A common mode choke coil that does not distort the signal waveform is required. In order to suppress the generation of the differential inductance generated by the differential signal current, a structure capable of suppressing the generation of the differential inductance by eliminating the magnetic flux generated by the differential current not only in the magnetic core but also in the space around the wire ring is required.

  The present invention is capable of taking noise countermeasures on differential signal lines without distorting the waveform even for high-speed signals, having a small stray capacitance between the two lines, a small differential inductance generated by a differential signal current, and a common that can be controlled. The main purpose is to provide a mode choke coil.

Invention of claims 1 to 6 is provided with both end portions magnetic co pair of electrodes are formed respectively on the A, linearly arranged separate pair of numbers of the same winding and Senwa, the pair one Senwa of Senwa is wound on one end side of the magnetic core, other Senwa of the pair of Senwa is wound on the other end side of the magnetic core the remaining two ends of the one line wheels, connected to said any two electrodes formed on the end portion of the magnetic core, both ends of the other Senwa is formed at an end of said magnetic core is connected to two electrodes of, Senwa of the said one line wheels other respectively, the magnetic flux that can be in the magnetic core is wound in a direction to be opposite to each other when the differential current flows It was a common mode choke coil. Provided is a common mode choke coil having a small stray capacitance between lines and a small differential inductance generated by a differential signal current. This common mode choke coil has two wire rings wound in the direction in which the magnetic flux generated in the core by the differential current is generated in the opposite direction on the magnetic core so that the winding axis is linear. By arranging the magnetic flux generated by the differential current, not only inside the core, but also in the space around the wire ring, the magnetic flux generated by the two wire rings can create a magnetic flux in the direction of canceling each other, and the differential inductance generated by the differential signal current Can be reduced. And since the location where stray capacitance is generated is almost limited to only one turn at the end where both the rings are adjacent to each other, the stray capacitance between both the rings is small, and the stray capacitance increases by increasing the number of turns. There is nothing.
The inventions of claims 1 to 6 provide a common mode choke coil in which windings respectively drawn from the pair of wire rings are close to each other at an end portion on the side where the pair of wire rings are close to each other. . If there is a winding disturbance, the common mode impedance will decrease at a high frequency, or if the winding disturbance is large, it will also cause resonance, so by bringing the windings of the two wire rings close together, Winding disturbance can be prevented and such problems can be prevented.

According to a second aspect of the invention, a common mode choke coil according to claim 1, both ends of the one line wheels connected to each of said pair of electrodes formed on one end portion of said magnetic core it is, both ends of the other wire loop is common mode choke coil which is connected to each of the pair of electrodes formed on the other end portion of the magnetic core.

The invention according to claim 3, a common mode choke coil according to claim 1, both ends of the one line wheels one said of the pair of electrodes formed on said one end of said magnetic core connected to each of the one of the pair of electrodes formed on the other end of the magnetic core, the other wire loop both ends of the pair of formed in the one end portion of said magnetic core a common mode choke coil that is connected to each of the remaining the remaining ones of the electrode the electrode ones of the pair of electrodes formed on the other end portion of the magnetic core electrode. This is an electrode arrangement in which the input / output electrode positions of the wire ring are arranged in the length direction of the magnetic core.

The invention according to claim 4, a common mode choke coil according to any one of claims 1 to 3, common to the ends of the both of the magnetic core is an I-shape became like a flange It is a mode choke coil. By providing ridges at both ends of the magnetic core, electrode formation is facilitated and mounting properties are reliably improved.

A fifth aspect of the present invention is the common mode choke coil according to any one of the first to fourth aspects, wherein the both ends of the magnetic core are magnetically short-circuited by a magnetic bar core to form a closed magnetic circuit. This is a formed common mode choke coil. By forming a magnetically shorted closed magnetic path with the bar core both ends of the magnetic material of the magnetic core, the stray capacitance between the two lines wheels is small, the differential inductance small go common mode choke generated by the differential signal current Configure the coil. A common mode choke coil having a small size, a large common mode impedance, a small stray capacitance, and a small differential inductance generated by a differential signal current can be produced.

A sixth aspect of the present invention is the common mode choke coil according to any one of the first to fifth aspects, wherein the adjacent windings of the pair of wire rings intersect each other at a substantially central portion of the magnetic core, It is a common mode choke coil in which some positions of the windings are interchanged .

As a result, the invention according to the sixth aspect of the present invention provides an input / output circuit for the common mode choke even if the stray capacitance between both lines of the common mode choke coil is slightly large or the differential inductance generated by the differential signal current is slightly large. If matching is performed with the transmission impedance, the differential mode signal can be distorted without distortion. According to the configuration of claim 6 , two adjacent windings of independent wire rings are crossed, the positions of a part of the windings are interchanged with each other, the stray capacitance between the two wire rings and the differential inductance are adjusted, and impedance matching is performed. An adjustable common mode choke can be provided.

The invention of claim 7 includes a magnetic core having a pair of electrodes formed at both ends, and a pair of wire rings having the same number of windings arranged and separated linearly, One of the wire rings is wound around one end of the magnetic core, and the other wire of the pair of wires is wound around the other end of the magnetic core. Both ends of the wire ring are connected to any two electrodes formed at the end of the magnetic core, and both ends of the other wire ring are the remaining two formed at the end of the magnetic core. The one wire ring and the other wire ring are respectively connected to electrodes and wound in directions in which magnetic fluxes generated in the magnetic core are opposite to each other when a differential current flows. The wire rings were respectively drawn from the pair of wire rings at the end portions on the side close to each other. A method of adjusting a common mode choke coil in which the windings are close to each other, wherein the adjacent windings of the pair of wire rings are crossed at a substantially central portion of the magnetic core, and a position of a part of the windings is Replacing each other, adjusting the amount of replacement of a part of the winding, and performing impedance matching between the common mode choke coil and a circuit connected to the common mode choke coil;
Is an adjustment method.

The present invention comprises a magnetic core in which a pair of electrodes are respectively formed on both ends, and a pair of Senwa of the number of same winding which is arranged separated in a straight line, one line wheels and the other line Each of the rings is wound in a direction in which magnetic fluxes generated in the magnetic core are opposite to each other when a differential current flows , and the pair of wire rings are arranged at the end portions on the side close to each other. Is a common mode choke coil in which windings respectively drawn out from each other face each other . With such a structure, a common mode choke coil having a small stray capacitance between lines and a small differential inductance generated by a differential signal current can be realized.

The common mode choke coil, a pair of Senwa magnetic flux has a winding direction generated in the opposite direction that can be in the magnetic core by the differential current on the magnetic core, so that the winding axis is a straight line To place . Accordingly, the magnetic flux generated by the differential current can be reduced not only inside of the magnetic core, it becomes the direction of canceling the each other physicians in the space around Senwa, the differential inductance generated by the differential signal current. The locations both lines wheels to be locations make generate stray capacitance are adjacent to be substantially restricted to one turn of the end, the stray capacitance between the two lines wheels is small, also large stray capacitance by increasing the number of turns It will never be. A chip for surface mounting becomes easy. Further, the winding disturbance can be prevented.

It is a figure which shows the structure of the common mode choke coil by which the conventional bifilar winding was generally used. It is a figure which shows the structural example of the conventional ring type common mode choke coil. It is a figure which shows the structural example of the common mode choke coil which inserted the magnetic body core in the conventional bobbin. It is a figure which shows the structural example of the common mode choke coil which combined the symmetrical coil which wound the conventional wire ring in the reverse direction. Ru Figure der to explain the principles of the common mode choke coil. Ru Figure der showing the relationship between the magnetic flux of the coil surrounding space in a conventional common mode choke coil. Ru Figure der showing a basic structure of a common mode choke coil in the first embodiment. Ru Figure der showing the structure of a common mode choke coil in the third embodiment. FIG. 10 is a diagram for explaining a differential current and a magnetic flux generated by the differential current in the common mode choke coil according to the third embodiment . Ru Figure der showing the structure of a common mode choke coil in the fourth embodiment. It is a figure which shows the structure of the common mode choke coil in Example 5 . It is a figure which shows the relationship between the stray capacitance by the simulation using the common mode choke coil in Example 5, and a signal waveform. It is a figure which shows the structure of the circuit used for simulation.

  Hereinafter, examples of the present invention will be described with reference to FIGS.

FIG. 7 is a diagram illustrating a basic structure of the common mode choke coil 1a according to the first embodiment. 7A is a front view, FIG. 7B is a side view, and FIG. 7C is a back view. As shown in FIG. 7, the magnetic core 2 made of a magnetic material such as ferrite has an I-shape with both end portions being hooked. The collar portion at both ends of the magnetic core 2, each of the pair of electrodes 4 and 5, and, providing a pair of electrodes 7 and 8. The tips of two wires coated with polyurethane or the like are connected to the electrodes 4 and 7 by a method such as welding . In this state, the magnetic core 2 is rotated, a pair of wire rings 3a and 6a having the same number of windings separated from both ends are wound, and two wires are drawn from the center to the other electrode 5 and electrode 8, Connect by welding. In the present embodiment, a pair of wire rings arranged in a straight line of a wire ring 3 a connected to the electrodes 4 and 5 and a wire ring 6 a connected to the electrodes 7 and 8 is configured. According to the configuration of the present embodiment, a common mode choke coil 1a having a small stray capacitance between both lines and a small differential inductance generated by a differential signal current can be obtained.

In Example 1, both ends of the wire constituting the wire ring 3a are connected to the electrodes 4 and 5, respectively, and both ends of the wire constituting the wire ring 6a are connected to the electrodes 7 and 8, respectively. . However, it is not limited to such a configuration. Although the illustration of the common mode choke coil 1a according to the second embodiment is omitted, the common mode choke coil 1a according to the second embodiment includes a pair of jaws at both ends of the magnetic core 2 made of a magnetic material such as ferrite. Electrodes 4 and 5 and a pair of electrodes 7 and 8 are provided . The tips of two wires over which the electrodes 4 and 7 are coated like a polyurethane connected by a method such as welding. In this state, the magnetic core 2 is rotated, a pair of wire rings 3a and 6a having the same number of windings separated from both ends are wound, and two wires are drawn from the center to the electrodes 8 and 5 at the other end, Connect by welding. In the present embodiment, a pair of a wire ring 3 a having an electrode arrangement with a structure connected to the electrodes 4 and 8 and a wire ring 6 a having an electrode arrangement with a structure connected to the electrodes 5 and 7 is configured. The electrode arrangement may be, for example, a pair of an electrode arrangement wire ring having a structure connected to the electrodes 4 and 7 and an electrode arrangement wire ring having a structure connected to the electrodes 5 and 8, and is optimal depending on the arrangement of the external circuit. Select a placement. An electrode arrangement that can reduce the mounting area during mounting can be employed .

FIG. 8 is a diagram illustrating the structure of the common mode choke coil 1b according to the third embodiment. 8A is a front view, FIG. 8B is a side view, and FIG. 8C is a back view. In the common mode choke coil 1b in the third embodiment, a pair of electrodes 4, 5 and a pair of electrodes on the flanges at both ends of the magnetic core 2 made of a magnetic material such as ferrite, respectively , as in the first and second embodiments . A pair of electrodes 7 and 8 are provided . The tips of two wires over which the electrodes 4 and 7 are coated like a polyurethane connected by a method such as welding. In this state, the magnetic core 2 is rotated, a pair of wire rings 3a and 6a having the same number of windings separated from both ends are wound, and two wires are drawn from the center to the other electrode 5 and electrode 8, Connect by welding. Magnetic poles 9 at both ends of the magnetic core 2 made of ferrite or the like are magnetically short-circuited by a magnetic bar core 9 to form a closed magnetic circuit. The flanges at both ends of the magnetic core 2 and the magnetic bar core 9 are joined together with an adhesive or the like.

In the present embodiment, a pair of a wire ring 3 a having an electrode arrangement with a structure connected to the electrodes 4 and 5 and a wire ring 6 a having an electrode arrangement with a structure connected to the electrodes 7 and 8 is configured.

Since the magnetic core 2 made of ferrite or the like has a structure in which the ridges and ridges at both ends thereof are magnetically short-circuited by the magnetic bar core 9 to form a closed magnetic circuit, the structure is smaller than the structure of the first embodiment shown in FIG. However, a larger common mode impedance can be obtained.

FIG. 9 is a diagram for explaining the differential current and the magnetic flux generated by the differential current in the common mode choke coil 1b according to the third embodiment. 9A is a front view, FIG. 9B is a side view, and FIG. 9C is a back view. FIG. 9 shows an operation model of the common mode choke coil 1b in the present embodiment. Figure 9 is a diagram showing the magnetic flux generated by the differential current and the differential current is the position of the relationship between the signal currents of the two coils (Senwa 3a, 6a).

In the common mode choke coil 1b of the present embodiment , the windings of the wire rings 3a and 6a of both lines are not alternating, and the winding shaft is separated on the magnetic core 2 in a straight line as in the first and second embodiments. Are arranged in a shape. That is, Senwa 3a of the common mode choke coil 1b (1a), 6a is only not adjacent one turn of each proximal end, stray capacitance is small, Ru can be suppressed small distortion of the differential transmission signal waveform. Therefore, the common mode choke coil 1b (1a) is never make increasing the stray capacitance proportionally be increased number of turns of the coil (Senwa 3a, 6a), not to increase the distortion of the signal waveform.

Also, differential as shown in FIG. 9, in this embodiment, a pair of Senwa 3a, axis winding 6a on the magnetic core 2 is arranged to be linear, pair of Senwa 3a, a 6a Winding is performed in a direction in which a magnetic flux generated in the magnetic core 2 by an electric current is generated in the opposite direction. Therefore, the magnetic flux generated by the differential signal current of the two wire rings 3a and 6a in the magnetic core 2 is canceled, and the direction of the magnetic flux generated in the space around the wire rings 3a and 6a is also generated in the direction to be canceled. Therefore, the differential inductance does not increase and the distortion of the signal waveform does not increase. Therefore, the differential inductance generated by the differential signal current can be reduced.

FIG. 10 is a diagram illustrating the structure of the common mode choke coil 1c according to the fourth embodiment. 10A is a front view, FIG. 10B is a side view, and FIG. 10C is a back view. In the common mode choke coil 1c according to the fourth embodiment of the present invention, a pair of electrodes 4 and 5 and a pair of electrodes 7 and 8 are provided on the flanges at both ends of the magnetic core 2 made of a magnetic material such as ferrite, respectively. It has been . The tips of two wires over which the electrodes 4 and 7 are coated like a polyurethane connected by a method such as welding. In this state, the magnetic core 2 is rotated, the pair of same winding number of Senwa 3c separated from both ends, winding 6c, two Senwa 3c at the proximal end of the substantially central portion of the magnetic core 2, 6c Ru twisted together the winding. Further , the wire from the wire ring 3c connected to the electrode 4 is drawn out to the electrode 5 and the wire from the wire ring 6c connected to the electrode 7 is drawn out to the electrode 8 and connected by welding or the like. According to this embodiment, a pair of a wire ring 3c having an electrode arrangement having a structure connected to the electrodes 4 and 5 and a wire ring 6c having an electrode arrangement having a structure connected to the electrodes 7 and 8 are formed.

If the winding of the wire ring is disturbed, the common mode impedance may decrease at high frequencies. Moreover, if this disturbance is large, it may cause resonance. However, the common mode choke coil 1c according to the present embodiment has a structure in which the windings drawn from the pair of wire rings 3c and 6c are close to each other at the end portion on the side where the pair of wire rings 3c and 6c are close to each other. It has become. The structure of the present embodiment is effective for preventing winding disturbance and loosening, and for improving manufacturing efficiency.

FIG. 11 is a diagram illustrating the structure of the common mode choke coil 1d according to the fifth embodiment. 11A is a front view, FIG. 11B is a side view, and FIG. 11C is a back view. In the common mode choke coil 1d according to the fifth embodiment of the present invention, a pair of electrodes 4 and 5 and a pair of electrodes 7 and 8 are provided on the flanges at both ends of the magnetic core 2 made of a magnetic material such as ferrite, respectively. It has been . The tips of two wires over which the electrodes 4 and 7 are coated like a polyurethane connected by a method such as welding. In this state, the magnetic core 2 is rotated, the pair of same winding number of Senwa 3d isolated from both ends, 6d winding rather. Two windings substantially central portion in a line wheels 3d of the magnetic core 2 adjacent, 6d crossed, switching the part of the position of the windings to each other, thereby Awa deviation two wires. Further, the wire from the wire ring 3d connected to the electrode 4 is drawn out to the electrode 5, and the wire from the wire ring 6d connected to the electrode 7 is drawn out to the electrode 8 and connected by welding or the like. The ridges and ridges at both ends of the magnetic core 2 are magnetically short-circuited by the magnetic bar core 9 to form a closed magnetic circuit. The flanges at both ends of the magnetic core 2 and the magnetic bar core 9 are joined together with an adhesive or the like.

Matching with the transmission impedance of the input / output circuit of the common mode choke coil 1d even if the stray capacitance between the two lines in the common mode choke coil 1d is slightly large or the differential inductance generated by the differential signal current is slightly large. If this is taken, it is possible to take noise countermeasures without distorting the differential mode signal. In that case, a structure that can finely adjust the stray capacitance between the wire rings and the differential inductance is required. In Example 5 shown in FIG. 11, the central portion in a line wheels 3d where two windings are adjacent, crossed 6d, replaced a portion of the positions of the windings to each other, by adjusting the replacement amount, two lines A common mode choke coil 1d in which the stray capacitance between the wheels 3d and 6d and the differential inductance are adjusted can be produced.

The positions of the central portions of the adjacent wire rings 3d and 6d can be replaced with each other not only at one place but also at a plurality of places, and may be twisted.

For example, the common mode choke coil 1a in the first embodiment, location where the stray capacitance is generated between the Senwa 3 and Senwa 6 is substantially limited to one turn of the central Ryosenwa is adjacent. Many of the electric line of force is generated, the line of both lines between the between Senwa 3 and Senwa 6 Senwa 3,6 via the magnetic core 2 or the Senwa 3 and Senwa 6 Stray capacitance is generated between the rings. According to the structure adopted in the common mode choke coil 1d of the fifth embodiment with respect to the arrangement of the adjacent wire rings 3 and 6, two wires are crossed at the time of final winding, and the final one turn is adjacent. when engulf all between line wheels for two Senwa 3d, the length of the portion adjacent to each other in 6d is ing three times as compared with the case of Senwa 3,6. Since the stray capacitance is proportional to the lengths of the adjacent portions in the wire ring, the stray capacitance can be increased and adjusted by up to about three times in the fifth embodiment compared to the first embodiment .

FIG. 12 is a diagram illustrating the relationship between the stray capacitance and the signal waveform by simulation using the common mode choke coil in the fifth embodiment. 12A is a diagram showing characteristics before adjustment, FIG. 12B is a diagram showing characteristics after adjustment, and FIG. 12C is a diagram showing characteristics when the stray capacitance is increased. is there. FIG. 13 is a diagram illustrating a configuration of a circuit used for the simulation. Using the common mode choke coil 1d manufactured in Example 5 , a simulation was performed to finely adjust the stray capacitance at a transmission speed of 500 MHz, and it was confirmed that the distortion of the signal waveform could be improved as shown in FIG. . For comparison, it shows a characteristic prototyped in Example 5 of the basic structure in FIG. 12 (A). When this stray capacitance is simulated at 1.5 pF close to the matching condition, the waveform distortion is reduced as shown in FIG. Further, when the simulation was performed at 3 pF with a larger stray capacitance, the signal waveform became dull as shown in FIG.

In the common mode choke coil 1d of this embodiment, the transmission impedance of the input / output circuit of the common mode choke coil 1d even if the stray capacitance between both lines is slightly large or the differential inductance generated by the differential signal current is slightly large. If matching is performed, noise countermeasures can be taken without distorting the differential mode signal.

  Digital devices are used in many fields, and differential signal transmissions such as typical interfaces, USB, LAN, LVDS, etc. are widely used in the digital devices, and the speed of differential signal transmission is increasing. As the speed increases, countermeasures against electromagnetic noise are required in the differential signal transmission line, and the common mode choke coil has become an indispensable important component for the countermeasures. However, in the countermeasures against electromagnetic noise of high-speed differential signal transmission, the stray capacitance of the common mode choke coil becomes a problem, and there is no countermeasure component that can take sufficient countermeasures. An inexpensive and effective solution is desired.

  In the present invention, a common mode choke coil having a small stray capacitance can be provided at low cost by linearly arranging and separating the wire ring through which the transmission signal passes, and the speed of digital electronic equipment can be increased. A contribution can be expected.

  Moreover, in the electromagnetic noise countermeasure of differential signal transmission, in order to obtain a large noise countermeasure effect, it is necessary to wind a large number of common mode choke coil wires to obtain a large common mode impedance. The conventional common mode choke coil has a problem that when a large number of wire rings are wound, the stray capacitance becomes large and the differential mode differential transmission signal cannot be distorted and a common mode choke coil having a large common mode impedance cannot be obtained. However, according to the present invention, since the number of windings and the stray capacitance are not directly related, a common mode choke coil having a large common mode impedance can be realized, and a large noise countermeasure effect can be obtained. This aspect can also be expected to contribute to the industry.

1 a, 1 b, 1 c, 1 d Common mode choke coil 2 Magnetic core 3 a, 3 c, 3 d, 6 a, 6 c, 6 d wire ring
4, 5, 7, 8 electrodes
9 Barcore

Claims (7)

And the magnetic core in which a pair of electrodes are respectively formed on both ends,
A pair of wire rings with the same number of windings arranged and separated linearly ;
With
One Senwa of the pair of Senwa is wound on one end side of the magnetic core, other Senwa of the pair of Senwa the other end portion side of the magnetic core Wound and
Both ends of the line ring of the one is connected to said any two electrodes formed on the end portion of the magnetic core, both ends of the other Senwa remaining formed at an end of said magnetic core is connected to two electrodes, the other Senwa and the one line wheels, respectively, it is wound in a direction in which the magnetic flux that can be in the magnetic core when the differential current flows are opposite to each other,
A common mode choke coil in which windings respectively drawn from the pair of wire rings are opposed to each other at an end portion on a side where the pair of wire rings are close to each other . The common mode choke coil according to claim 1,
Both ends of the line ring of the one is connected to each of the one pair of electrodes formed on an end portion of the magnetic core, both ends of the other wire wheel formed on the other end of said magnetic core been benzalkonium common mode choke coil is connected to each of the pair of electrodes. The common mode choke coil according to claim 1,
Wherein both ends of one line wheels with one of said one end portion formed the pair of one said pair of electrodes formed on the other end of the magnetic core of the electrode of the magnetic core are respectively connected to the ends of the other wire wheel which is formed on the other end of the electrode and the magnetic core remaining ones of said one end portion and the pair of electrodes formed on said magnetic core electrode and of Turkey common mode choke coil is connected to each remaining ones of the pair of electrodes. The common mode choke coil according to any one of claims 1 to 3,
The benzalkonium common mode choke coil ends of the both magnetic core has an I-shape became flange shape. A common mode choke coil according to any one of claims 1 to 4,
The magnetically shorted common mode choke coil forming a closed magnetic circuit the both ends of the magnetic core in the bar core of magnetic material. A common mode choke coil according to any one of claims 1 to 5,
A common mode choke coil in which adjacent windings of the pair of wire rings are crossed at a substantially central portion of the magnetic core, and positions of a part of the windings are interchanged with each other . A magnetic core having a pair of electrodes formed on both ends, and a pair of wire rings having the same number of windings arranged and separated linearly, and one wire ring of the pair of wire rings is Winded on one end side of the magnetic core, the other wire of the pair of wire rings is wound on the other end side of the magnetic core, and both ends of the one wire ring are Connected to any two electrodes formed at the end of the magnetic core, and both ends of the other wire ring are connected to the remaining two electrodes formed at the end of the magnetic core, The other wire ring and the other wire ring are wound in directions in which magnetic fluxes generated in the magnetic core are opposite to each other when a differential current flows, and the pair of wire rings are close to each other. Windings respectively drawn from the pair of wire rings approach each other. A it has been a method of adjusting the common mode choke coil,
Crossing adjacent windings of the pair of wire rings at a substantially central portion of the magnetic core, and replacing the positions of some of the windings with each other;
Adjusting the amount of replacement of a part of the winding to perform impedance matching between the common mode choke coil and a circuit connected to the common mode choke coil;
An adjustment method comprising:

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