JP2007036158A - Inductance element and signal transmitting circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a signal transmitting circuit in which deterioration in characteristic impedance can be prevented even if a capacitive element is used for countermeasures against ESD. <P>SOLUTION: First and second inductors 11 and 12 are magnetically coupled to each other. Third and fourth inductors 21 and 22 are also magnetically coupled to each other. A first varistor 31 is positioned on post-stage of the first inductor 11, and electrically connected to the inductors 11 and 21 in parallel. The third inductor 21 is positioned between the first inductor 11 and the first varistor 31, and electrically connected to the first inductor 11 in series. A second varistor 32 is positioned on post-stage of the second inductor 12, and electrically connected to the second inductor 12 in parallel. The fourth inductor 22 is positioned between the second inductor 12 and the second varistor 32, and electrically connected to the second inductor 12 in parallel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inductance element and a signal transmission circuit.

  One method for transmitting digital signals between electronic devices is a differential transmission method. The differential transmission system is a system in which digital signals in opposite directions are input to a pair of lines, and radiation noise generated from the signal line and external noise can be canceled by differential transmission. Since the noise is reduced by canceling out the external noise, the signal can be transmitted with a small amplitude. Further, since the signal has a small amplitude, the rise and fall times of the signal are shortened, and the signal transmission speed is increased. There is an advantage that is realized.

  Examples of interface standards using this differential transmission method include USB (Universal Serial Bus), IEEE 1394, LVDS (Low Voltage Differential Signaling), DVI (Digital Visual Interface), HDMI (High-Definition Multimedia Interface), and the like. Among these, HDMI is an interface that enables transmission of more digital signals, and is a source device (for example, a DVD player or a set-top box) and a sink device (for example, a digital TV or a projector). Etc.) is a high-speed interface that enables transmission of uncompressed digital signals. According to HDMI, a video signal and an audio signal can be transmitted at a high speed with a single cable.

By the way, with an increase in transmission speed, noise is also generated due to a minute shift of a differential signal between signal lines. In order to solve this problem, a transmission circuit that reduces noise by inserting a common mode choke coil in an interface such as a cable has been proposed (for example, see Patent Document 1).
JP 2001-85118 A JP 2004-40444 A

  In high-speed interfaces such as HDMI, the structure of the IC itself is becoming vulnerable to ESD (Electrostatic Discharge) in order to realize high speed. For this reason, there is an increasing demand for ESD countermeasures in high-speed transmission ICs, and capacitive elements such as varistors and Zener diodes are used as ESD countermeasure components.

  However, when a capacitive element as an ESD countermeasure component is inserted into a transmission line, a problem arises that a signal transmitted through the transmission line, particularly a high frequency (200 MHz or higher) or a high-speed pulse signal is reflected and attenuated. found. This is because when a capacitive element is inserted into a transmission line, the capacitive component of the capacitive element reduces the characteristic impedance at the position where the capacitive element is inserted in the transmission line, and impedance matching is performed at that position. This is due to the absence. If there is a portion of the transmission line that is not impedance matched, a high frequency component of the signal is reflected at the mismatched portion of the characteristic impedance, resulting in a return loss. As a result, the signal is greatly attenuated. In addition, unnecessary radiation may be generated in the transmission line due to reflection, which may cause noise.

  In HDMI, the specified value (TDR standard) of the characteristic impedance of the transmission line is defined as 100Ω ± 15% (High-Definition Multimedia Interface Specification Version 1.1).

  An object of the present invention is to provide a signal transmission circuit that can suppress a decrease in characteristic impedance even when a capacitive element is used as an ESD countermeasure, and an inductance element that can be used in such a signal transmission circuit. There is to do.

  An inductance element according to the present invention includes a drum core having a winding core and first and second flanges provided at both ends thereof, and first and second terminal electrodes formed on the first flange. And the third and fourth terminal electrodes formed on the second flange portion, and the winding core portion is wound in a predetermined direction from one end to the other end, and one end is connected to the first terminal electrode. The other end is wound in a direction different from the predetermined direction from one end to the other end, and the other end is connected to the second terminal. And a second coil connected to the terminal electrode and having the other end connected to the fourth terminal electrode.

  Thus, in the inductance element according to the present invention, the winding direction of the first coil starting from the first terminal electrode is opposite to the winding direction of the second coil starting from the second terminal electrode. Therefore, the first and second inductors that are magnetically coupled to each other, the first capacitive element that is located behind the first inductor and is electrically connected in parallel to the first inductor, A first capacitive element and a second capacitive element by being inserted into a signal transmission circuit that is located downstream of the second inductor and includes a second capacitive element electrically connected in parallel to the second inductor; A decrease in characteristic impedance due to can be suppressed.

  That is, in the inductance element according to the present invention, the first and second coils are magnetically coupled to each other and the winding directions are opposite to each other. And the second terminal electrode are connected to the first and second inductors, respectively, and the third and fourth terminal electrodes of the inductance element according to the present invention are connected to the first and second capacitive elements, respectively, A sufficient inductance value can be ensured with a smaller number of turns than in the case where the magnetic coupling is not performed. For this reason, it is possible to suppress a decrease in characteristic impedance due to the first and second capacitive elements with a smaller inductance element.

  In addition, since the first and second coils are not separated from each other but are one component that is magnetically coupled, the inductance value can be accurately balanced, and as a result, the first and second terminal electrodes It is possible to maintain the symmetry of the differential signal supplied to the.

  In the present invention, the first coil and the second coil preferably intersect at a plurality of locations. If the first coil and the second coil are wound around the core so that they intersect at a plurality of locations, one end of each of the first and second coils is drawn to the first flange side, and the first and second coils Since it becomes easy to pull out the other end of the 2nd coil to the 2nd collar side, it becomes possible to connect these coils and a terminal electrode easily.

  In this case, the number of crossings between the first coil and the second coil is preferably greater than the number of turns of the first coil and the number of turns of the second coil, and the number of crossings is equal to the number of turns of the first coil and the second coil. It is particularly preferred to be equal to the sum of the number of turns of the coil. According to these, it becomes possible to connect the first and second coils and the terminal electrode more easily.

  In addition, the inductance element according to the present invention preferably further includes a separation unit that separates the first coil and the second coil in the intersection region between the first coil and the second coil. By using such a separation means, short circuit failure or disconnection due to contact between coils does not occur, and the reliability of the product can be improved.

  In this case, the separating means may be constituted by unevenness provided in the core part, or may be an insulator provided between the first coil and the second coil. In the case where the separating means is constituted by the unevenness of the core part, the unevenness includes a first part for allowing the first coil to pass over the second coil while being separated, and the second coil being the first coil. It is particularly preferable that the second portion is included so as to pass while being spaced apart. According to this, the lengths of the first coil and the second coil can be made equal, and the influence of the winding core portion on the first and second coils can be made equal. Thereby, since the symmetry of the first coil and the second coil becomes higher, the signal quality can be improved.

  Thus, the signal transmission circuit according to the present invention can suppress a decrease in characteristic impedance even when a capacitive element is used as an ESD countermeasure. In addition, since the winding directions of the two coils included in the inductance element inserted into the signal transmission circuit are opposite to each other, a sufficient inductance value can be ensured with a smaller number of turns. For this reason, it is possible to suppress a decrease in characteristic impedance due to the capacitive element by a smaller inductance element.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  (First embodiment of signal transmission circuit)

  First, based on FIG.1 and FIG.2, the structure of the signal transmission circuit which concerns on 1st Embodiment is demonstrated. FIG. 1 is a schematic diagram illustrating a signal transmission circuit according to the first embodiment. FIG. 2 is a circuit diagram showing the signal transmission circuit according to the first embodiment.

  As shown in FIG. 1, the digital television 1 and the DVD player 2 are connected by an HDMI cable 3. The HDMI cable 3 is a cable using a differential transmission method, and includes connection terminal portions 5 and 6 (connectors). The connection terminal portion 5 of the HDMI cable 3 is connected to the output portion of the DVD player 2. The connection terminal portion 6 of the HDMI cable 3 is connected to the input portion of the digital television 1. The digital signal output from the DVD player 2 is transmitted at high speed to the digital television 1 through the HDMI cable 3.

  The digital television 1 has a signal transmission circuit SC1 at its input. As shown in FIG. 2, the signal transmission circuit SC1 includes a common mode filter 10 having first and second inductors 11 and 12 magnetically coupled to each other, and a third and fourth inductor 21 magnetically coupled to each other. , 22, and first and second varistors 31, 32. The common mode filter 10 has input / output terminals 13 and 14 connected to the first inductor 11 and input / output terminals 15 and 16 connected to the second inductor 12. The input terminals 13 and 15 of the common mode filter 10 are connected to corresponding terminals of the connection terminal unit 6 when the connection terminal unit 6 of the HDMI cable 3 is connected to the input unit of the digital television 1.

  Here, the structure and operation of the common mode filter 10 will be described with reference to FIGS. 3A and 3B are schematic diagrams for explaining the operation of the common mode filter.

  The common mode filter 10 has a configuration in which two conductive wires (coils) 17 and 18 insulated from each other are wound around a ferrite core 19 a plurality of times in the same direction. The conducting wire 17 constitutes the first inductor 11, and the conducting wire 18 constitutes the second inductor 12. The shape of the ferrite core 19 is not necessarily the illustrated ring shape.

  In the present embodiment, the common mode filter 10 is used in a differential mode for signals. In the differential mode, as shown in FIG. 3A, the signal SI is input to the conducting wires 17 and 18 as signals in opposite directions. Therefore, the magnetic fluxes F1 and F2 generated in the ferrite core 19 by the conductive wires 17 and 18 become magnetic fluxes in opposite directions, and act so as to cancel each other. Accordingly, since there is almost no impedance (inductance) caused by the magnetic field MF generated by the conducting wires 17 and 18, the signal SI is output with almost no attenuation.

  On the other hand, for the common mode noise CN, the common mode filter 10 is used in the common mode. In the common mode, as shown in FIG. 3B, common mode noise CN occurs in the same direction of the conducting wires 17 and 18. Therefore, the magnetic fluxes F1 and F2 generated in the ferrite core 19 by the conductive wires 17 and 18 become magnetic fluxes in the same direction, and act to strengthen each other. Therefore, the impedance (inductance) generated by the magnetic field MF generated by the conducting wires 17 and 18 is increased, and the common mode noise CN is hardly output. In this way, the common mode filter 10 can attenuate noise.

  Reference is again made to FIG. The inductance element 20 has a pair of input terminals 23 and 25 and a pair of output terminals 24 and 26, and the pair of input terminals 23 and 25 is connected to the common mode filter 10 via signal lines 91 and 92. The output terminals 14 and 16 are connected respectively. Similar to the common mode filter 10 described above, the inductance element 20 has a configuration in which two inductors 21 and 22 that are insulated from each other are wound around a ferrite core a plurality of times, whereby the third and fourth inductors are formed. 21 and 22 are magnetically coupled to each other. However, in the inductance element 20, unlike the common mode filter 10, the winding directions of two conductive wires (coils) constituting two inductors are opposite to each other. For this reason, the inductance element 20 becomes a common mode with respect to a signal, and becomes a differential mode with respect to common mode noise. A more specific configuration of the inductance element 20 will be described later.

  The third inductor 21 included in the inductance element 20 is electrically connected in series to the first inductor 11 via the signal line 91. The third inductor 21 is not substantially magnetically coupled to the first inductor 11. The first varistor 31 has input / output terminals 33 and 34. The input terminal 33 of the first varistor 31 is connected to the output terminal 24 of the inductance element 20 via the signal line 93. The output terminal 34 of the first varistor 31 is connected to the ground potential. As a result, the first varistor 31 is positioned after the first inductor 11 and the third inductor 21 and is electrically connected in parallel to the first inductor 11 and the third inductor 21. . In addition, the third inductor 21 is located between the first inductor 11 and the first varistor 31.

  The fourth inductor 22 included in the inductance element 20 is electrically connected in series to the second inductor 12 via the signal line 92. The fourth inductor 22 is not substantially magnetically coupled to the second inductor 12. The second varistor 32 has input / output terminals 35 and 36. The input terminal 35 of the second varistor 32 is connected to the output terminal 26 of the inductance element 20 via the signal line 94. The output terminal 36 of the second varistor 32 is connected to the ground potential. Thus, the second varistor 32 is positioned after the second inductor 12 and the fourth inductor 22 and is electrically connected in parallel to the second inductor 12 and the fourth inductor 22. . In addition, the fourth inductor 22 is located between the second inductor 12 and the second varistor 32.

  As the common mode filter 10, for example, a common mode filter included in an ACM series manufactured by TDK Corporation can be used. As the first and second varistors 31 and 32, for example, a multilayer chip varistor included in the AVR series manufactured by TDK Corporation can be used.

  As described above, in the first embodiment, the common mode filter 10 (first and second inductors 11 and 12) is inserted in front of the first and second varistors 31 and 32, and the common mode filter 10. Since the third and fourth inductors 21 and 22 constituting the inductance element 20 are respectively inserted between the first and second varistors 31 and 32, the first and second varistors 31 and 32 are inserted. A decrease in characteristic impedance due to can be suppressed.

  In addition, the third and fourth inductors 21 and 22 are magnetically coupled to each other, and the winding directions of the two conductors constituting the inductors 21 and 22 are opposite to each other. A sufficient inductance value can be ensured with a smaller number of turns than in the case of no coupling. For this reason, the size of the inductance element 20 constituting the third and fourth inductors 21 and 22 can be reduced. Furthermore, since the third and fourth inductors 21 and 22 are not separated from each other but are one component that is magnetically coupled, the inductance value can be accurately balanced, and as a result, the differential signal is symmetrical. It becomes possible to maintain sex.

  In the first embodiment, since the common mode filter 10 is inserted in front of the first and second varistors 31 and 32, the signal output from the DVD player 2 is hardly accompanied by external noise. , And input to the digital television 1 through the HDMI cable 3 and the signal transmission circuit SC1.

  Next, a specific configuration of the inductance element 20 will be described.

  (First Embodiment of Inductance Element)

  FIG. 4 is a schematic perspective view showing the structure of the inductance element 20 according to the first embodiment. FIG. 5A is a top view of the inductance element 20, and FIG. 5B is a side view of the inductance element 20.

  As shown in FIGS. 4 and 5, the inductance element 20 according to the present embodiment includes a drum-type core 110 and first and second coils 121 and 122. The drum core 110 includes a rod-shaped core portion 130 and first and second flange portions 141 and 142 provided at both ends thereof. First and second terminal electrodes 151 and 152 are formed on the first flange 141, and third and fourth terminal electrodes 153 and 154 are formed on the second flange 142. In actual use, the first and second terminal electrodes 151 and 152 are used as the pair of input terminals 23 and 25 shown in FIG. 2, and the third and fourth terminal electrodes 153 and 154 are 2 is used as a pair of output terminals 24 and 26 shown in FIG. The material of the drum core 110 is not particularly limited, but it is preferable to use a material having high magnetic permeability, such as ferrite.

  The first and second coils 121 and 122 are wiring members in which the periphery of a conductor such as copper (Cu) is coated with an insulator, and both are wound around the core portion 130 of the drum core 110. The first and second coils 121 and 122 are coils that constitute the third and fourth inductors 21 and 22, respectively, shown in FIG.

  More specifically, the first coil 121 has one end 121 a connected to the first terminal electrode 151 and the other end 121 b connected to the third terminal electrode 153. The second coil 122 has one end 122 a connected to the second terminal electrode 152 and the other end 122 b connected to the fourth terminal electrode 154. Further, when viewed from the arrow A shown in FIG. 4, the first coil 121 is wound clockwise (clockwise) from one end 121a to the other end 121b, while the second coil 122 has one end 122a. Is wound counterclockwise (counterclockwise) toward the other end 122b. In other words, the winding direction of the first coil 121 starting from the first terminal electrode 151 and the winding direction of the second coil 152 starting from the second terminal electrode 152 are opposite to each other. It has become.

  The winding directions of the first and second coils 121 and 122 are not particularly limited as long as they are opposite to each other. Therefore, the directions are opposite to the above, that is, the first coil is counterclockwise ( The second coil may be clockwise (clockwise).

  In the present embodiment, every time the first and second coils 121 and 122 make one round of the core part 130, the first and second coils 121 and 122 intersect once on the upper surface 131 of the core part 130. At the same time, the first and second coils 121 and 122 intersect once on the lower surface 132 of the core portion 130. In the present embodiment, since the number of turns of the first coil 121 and the number of turns 122 of the second coil are both four, the total number of crossings between the first coil 121 and the second coil 122 is 8 in total. Times. That is, the number of crossings is equal to the sum of the number of turns of the first coil 121 (four times) and the number of turns of the second coil 122 (four times). According to such a winding method, since the winding method of the first and second coils 121 and 122 is uniform, it is possible to ensure high symmetry.

  Of course, in the present invention, the number of turns of the first and second coils 121 and 122 is not limited to this, and may be any number of turns. However, in order to maintain the symmetry of the first and second coils 121 and 122, the number of turns of the first coil 121 and the number of turns of the second coil 122 need to be the same. In order not to attenuate the signal excessively, it is preferable that the number of turns of the first and second coils 121 and 122 is sufficiently smaller than that of the common mode filter 10.

  FIG. 6 is a diagram for explaining a wiring pattern on the substrate on which the inductance element 20 is mounted.

  The inductance element 20 according to the present embodiment includes two terminal electrodes (first electrodes) used as a pair of input terminals 23 and 25, although the winding directions of the first and second coils 121 and 122 are opposite to each other. 1 and the second terminal electrodes 151 and 152) are formed in the same collar, and the two terminal electrodes (third and fourth terminal electrodes 153 and 154) used as the pair of output terminals 24 and 26 are the same As shown in FIG. 6, the pair of signal lines 91 and 92 can be laid in parallel on the substrate 190 and the pair of signal lines 93 and 94 are laid in parallel as shown in FIG. be able to. This eliminates the need for bypassing the wiring pattern on the substrate 190. Therefore, the occupied area of the wiring pattern on the substrate 190 does not increase more than necessary, and high symmetry can be ensured. As a result, it is possible to simultaneously reduce the size of the entire apparatus and improve the signal quality.

  The above is the specific configuration of the inductance element 20 according to the first embodiment.

  Next, a configuration of a modification of the signal transmission circuit SC1 according to the first embodiment will be described with reference to FIGS. 7 to 9 are diagrams illustrating modifications of the signal transmission circuit according to the first embodiment.

  In the modification shown in FIG. 7, the HDMI cable 3 includes a signal transmission circuit SC1.

  In the modification shown in FIG. 8, the DVD player 2 has a signal transmission circuit SC1 at its output.

  In the modification shown in FIG. 9, the connection terminal portion 6 (connector) of the HDMI cable 3 includes a signal transmission circuit SC1. Instead of the connection terminal portion 6 of the HDMI cable 3 including the signal transmission circuit SC1, the connection terminal portion 5 (connector) of the HDMI cable 3 may include the signal transmission circuit SC1.

  In any of the modifications shown in FIGS. 7 to 9, it is possible to suppress a decrease in characteristic impedance due to the first and second varistors 31 and 32.

  (Second Embodiment of Inductance Element)

  FIG. 10 is a schematic perspective view showing the structure of the inductance element 60 according to the second embodiment. FIG. 11A is a top view of the inductance element 60, and FIG. 11B is a bottom view of the inductance element 60. Further, FIG. 12A is a cross-sectional view taken along line A1-A1 in FIG. 11A, and FIG. 12B is a cross-sectional view taken along line B1-B1 in FIG.

As shown in FIGS. 10 to 12, in the inductance element 60 according to the present embodiment, four groove portions 131 a _{1 to} 131 a ₄ (collectively referred to as groove portions 131 a) are formed on the upper surface 131 of the core portion 130. Four groove portions 132a _{1 to} 132a ₄ (collectively referred to as groove portions 132a) are formed on the lower surface 132 of the core portion 130. The first coil 121 is accommodated in the grooves 131a and 132a. Thereby, the second coil 122 passes over the first coil 121 while being separated from each other in the crossing region X1 on the upper surface side and the crossing region X2 on the lower surface side. Since the other points are the same as those of the inductance element 20 according to the above-described embodiment, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 12B, the depths D1 of the grooves 131a and 132a are set to be at least the diameter D2 of the first coil 121. As a result, in the intersecting regions X1 and X2, the first coil 121 and the second coil 122 are separated by a distance D3 (= D1-D2).

  As described above, the inductance element 60 according to the present embodiment accommodates the first coil 121 in the groove portions 131a and 132a formed in the winding core portion 130, so that the first coil 121 and the first coil 121 in the intersecting regions X1 and X2 Since contact with the second coil 122 is prevented, short circuit failure or disconnection due to contact between the coils does not occur, and the reliability of the product can be improved. The coil housed in the groove portions 131a and 132a is not limited to the first coil 121, and may be the second coil 122.

  13 and 14 are process diagrams for explaining a method for manufacturing the inductance element 60.

  First, as shown in FIG. 13, the first and second terminal electrodes 151 and 152 are formed on the first flange 141 of the drum core 110, and the third and fourth terminals are formed on the second flange 142. Terminal electrodes 153 and 154 are formed. The groove portions 131a and 132a described above are formed in advance in the core portion 130 of the drum core 110.

  Next, as shown in FIG. 14, the first coil 121 is wound around the core 130 along the grooves 131a and 132a, one end 121a is connected to the first terminal electrode 151, and the other end 121b is connected to the first coil 121. 3 terminal electrodes 153.

  Then, as shown in FIG. 10, while intersecting with the first coil 121, the second coil 122 is wound around the core 130, one end 122 a is connected to the second terminal electrode 152, and the other end When 122b is connected to the fourth terminal electrode 154, the inductance element 60 according to the present embodiment is completed. As described above, the inductance element 60 according to the present embodiment can wind the second coil 122 around the core portion 130 after winding the first coil 121 around the core portion 130. It is efficient and can be assembled easily.

  (Third embodiment of inductance element)

  FIGS. 15A and 15B are a top view and a bottom view of the inductance element 70 according to the third embodiment, respectively. 16A is a cross-sectional view taken along line A2-A2 in FIG. 15A, and FIG. 16B is a cross-sectional view taken along line B2-B2 in FIG. A perspective view of the inductance element 70 according to the third embodiment viewed obliquely from above is the same as FIG.

  As shown in FIGS. 15 and 16, the inductance element 70 according to the present embodiment has a groove 131 a formed on the upper surface 131 of the core 130 and a groove 132 a formed on the lower surface 132 of the core 130. The inductance element 60 is the same as the inductance element 60 according to the second embodiment described above, except that the first coil 121 is accommodated in the groove 131a and the second coil 122 is accommodated in the groove 131b. 60. Since the other points are the same as those of the inductance element 60, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  With such a configuration, in the crossing region X3 on the upper surface 131 side of the core part 130, the second coil 122 passes over the first coil 121 while being separated, and the crossing on the lower surface 132 side of the core part 130. In the region X4, the first coil 121 passes over the second coil 122 while being separated. For this reason, in the present embodiment, not only the contact between the first coil 121 and the second coil 122 in the intersecting regions X3 and X4 is prevented, but also the lengths of the first coil 121 and the second coil 122. Can be made equal, and the influence of the winding core 130 on the first and second coils 121 and 122 can be made equal. For this reason, according to this embodiment, since the symmetry of the 1st coil 121 and the 2nd coil 122 becomes higher, it becomes possible to improve signal quality.

  FIG. 17 is a process diagram for explaining a method of manufacturing the inductance element 70.

  First, as shown in FIG. 13, the first and second terminal electrodes 151 and 152 are formed on the first flange 141, and the third and fourth terminal electrodes 153 and 154 are formed on the second flange 142. A drum-type core 110 is prepared. Next, as shown in FIG. 17, one end 121 a of the first coil 121 is connected to the first terminal electrode 151, and one end 122 a of the second coil 122 is connected to the second terminal electrode 152.

From this state, after winding the first coil 121 around the core portion 130 along the first groove 131a ₁ closest to the first flange 141, the first coil closest to the first flange 141 is placed. The second coil 122 is wound around the core portion 130 along the groove portion 132a ₁ (not shown in FIG. 17 because it is the back surface). Subsequently, the first coil 121 is wound around the winding core portion 130 along the _second groove portion 131a ₂ , and the _second coil portion 132a ₂ (not shown in FIG. 17 for the back surface) is further wound along the second coil portion 131a ₂ . The coil 122 is wound around the core portion 130. In this way, the first coil 121 and the second coil 122 are alternately wound around the core portion 130. Finally, as shown in FIG. 10, the other end 121b of the first coil 121 is connected to the third coil portion 130. Connected to the terminal electrode 153, the other end 122 b of the second coil 122 is connected to the fourth terminal electrode 154.

  Thus, the inductance element 70 according to the present embodiment is completed. The winding method of the first and second coils 121 and 122 in the inductance element 70 is not limited to the method of alternately winding as described above, and one coil (for example, the first coil 121) is connected. After winding all around the core portion 130, the other coil (for example, the second coil 122) may be wound around the core portion 130 so as to pass through the corresponding groove portion (for example, the groove portion 132b).

  (Fourth Embodiment of Inductance Element)

  FIG. 18 is a schematic perspective view showing the structure of the inductance element 80 according to the fourth embodiment. FIGS. 19A and 19B are a top view and a bottom view of the inductance element 80, respectively. Further, FIG. 20 is a cross-sectional view taken along line B3-B3 in FIG.

As shown in FIGS. 18 to 20, in the inductance element 80 according to the present embodiment, four protrusions 131 b _{1 to} 131 b ₄ (these are collectively referred to as a protrusion 131 b) are formed on the upper surface 131 of the core part 130. Four projecting portions 132b _{1 to} 132b ₄ (collectively referred to as projecting portions 132b) are formed on the lower surface 132 of the core portion 130. The protrusions 131b and 132b may be a part of the core part 130, or may be another member added to the core part 130.

  On the upper surface 131 side of the core portion 130, the second coil 122 is wound so as to be in contact with the upper surface of the protruding portion 131 b, and the upper surface 131 of the core portion 130 and the second coil 122 generated by this are wound. The first coil 121 is wound around the gap so as to avoid the protrusion 131b. Conversely, on the lower surface 132 side of the core part 130, the first coil 121 is wound so as to be in contact with the upper surface of the protruding part 132b. The second coil 122 is wound around the gap of the coil 121 while avoiding the protrusion 132b. Since the other points are the same as those of the inductance element 20 according to the above-described embodiment, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  As shown in FIG. 20, the heights D4 of the protrusions 131b and 132b are set to be at least the diameter D2 of the first and second coils 121 and 122. That is, in the intersecting regions X5 and X6, a gap of a distance D4 is generated at the maximum between the first or second coil 121, 122 and the flat surface of the core part 130. If the second coils 121 and 122 are passed, the first coil 121 and the second coil 122 can be separated by a distance D5 (= D4-D2) at the maximum.

  With such a configuration, in the crossing region X5 on the upper surface 131 side of the core part 130, the second coil 122 passes over the first coil 121 while being separated, and the lower part 132 side of the core part 130 is crossed. In the region X6, the first coil 121 passes over the second coil 122 while being separated. For this reason, also in the present embodiment, short circuit failure or disconnection due to contact between the coils does not occur, and the reliability of the product can be improved.

  Further, the inductance element 80 according to the present embodiment can make the lengths of the first coil 121 and the second coil 122 equal to each other and the first and second coils, similarly to the inductance element 70 according to the third embodiment. The influence of the core part 130 on the coils 121 and 122 can be made uniform. Therefore, the signal quality can be improved as in the inductance element 70 according to the third embodiment.

  However, when the protrusion is used, it is not essential to adopt the above-described configuration, and the first coil 121 (or the second coil 122) is provided on both the upper surface 131 and the lower surface 132 of the winding core 130. You may wind so that it may touch the upper surface of protrusion part 131b, 132b.

  The shape of the protrusion is not particularly limited, but in order to prevent the coil wound on the protrusion from falling off and to increase the work efficiency of the winding operation, it is shown in FIG. Thus, it is preferable to provide a recess 131x on the upper surface of each protrusion 131b, 132b, or to provide a guide 131y on the upper surface of each protrusion 131b, 132b as shown in FIG.

  In the second and third embodiments, the core portion 130 is provided with a groove portion, and in the fourth embodiment, the core portion 130 is provided with a protruding portion, whereby the first and second coils 121 and 122 in the intersecting region are provided. Although the contact is prevented, in short, any shape may be adopted as long as the first and second coils 121 and 122 can be separated by the unevenness provided in the core portion 130. In addition, the distinction between a concave portion and a convex portion is only relative. Therefore, in the second and third embodiments, a region where the groove is not formed can be regarded as a convex portion, and in the fourth embodiment, a region where the protrusion is not formed can be regarded as a concave portion. it can.

  Furthermore, as shown in FIG. 22 which is a front view and a side view, when the cross section of the core portion 130 is a hexagon, a plurality of slits 138a and 139a are formed in the opposite corner portions 138 and 139, respectively. If it puts in, the effect similar to 2nd-4th embodiment can be acquired. That is, as shown in FIG. 23 which is a top view, when the first coil 121 is wound along the slit 138a and the second coil 122 is wound so as to straddle the slit 138a, two coils are wound. Can be separated. Similarly, the second coil 122 may be wound along the slit 139a on the opposite side of the surface shown in FIG. 23, and the first coil 121 may be wound across the slit 139a.

  (Fifth Embodiment of Inductance Element)

  FIG. 24 is a schematic perspective view showing the structure of the inductance element 90 according to the fifth embodiment.

  As shown in FIG. 24, in the inductance element 90 according to the present embodiment, an insulating film 131 c provided between the first coil 121 and the second coil 122 is added to the upper surface 131 side of the core portion 130. An insulating film 132c provided between the first coil 121 and the second coil 122 is added to the lower surface 132 side of the core portion 130. Since the other points are the same as those of the inductance element 20 according to the first embodiment, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  In the inductance element 90 according to the present embodiment, the first and second coils 121 and 122 are not separated by the unevenness provided on the winding core portion 130 but are separated by the insulating films 131c and 132c. Also by such a method, it is possible to prevent short-circuit failure or disconnection due to contact between coils, so that the reliability of the product can be improved. The material of the insulating films 131c and 132c is not particularly limited, but it is preferable to select a material that is thin and difficult to break.

  25 and 26 are process diagrams for explaining a method of manufacturing the inductance element 90. FIG.

  First, as shown in FIG. 25, the first coil 121 is wound around the core 130, one end 121 a is connected to the first terminal electrode 151, and the other end 121 b is connected to the third terminal electrode 153. . Then, as shown in FIG. 26, the first coil 121 located on the upper surface 131 of the core part 130 is covered with an insulating film 131c. Similarly, the first coil 121 located on the lower surface 132 of the core part 130 is covered with the insulating film 132c.

  Then, as shown in FIG. 24, the second coil 122 is wound around the core 130 from above the insulating films 131c and 132c, one end 122a is connected to the second terminal electrode 152, and the other end 122b is connected. When connected to the fourth terminal electrode 154, the inductance element 90 according to the present embodiment is completed. As described above, the inductance element 90 according to the present embodiment can wind the second coil 122 around the core portion 130 after winding the first coil 121 around the core portion 130. It is efficient and can be assembled easily.

  As mentioned above, although several embodiment regarding an inductance element was described, as for the inductance element by any embodiment, the 1st and 2nd coils 121 and 122 are mutually magnetically coupled, and 1st and 2nd The winding directions of the coils 121 and 122 are opposite to each other. For this reason, compared with the case where it is not magnetically coupled, a sufficient inductance value can be secured with a smaller number of turns, and the size of the inductance element can be reduced. Moreover, the inductance elements according to the respective embodiments can balance the inductance values with high accuracy, and can maintain the symmetry of the differential signal. For this reason, if the inductance element according to each embodiment is used, it is possible to simultaneously reduce the size of the entire apparatus and improve the signal quality.

  (Second Embodiment of Signal Transmission Circuit)

  Next, the configuration of the signal transmission circuit according to the second embodiment will be described with reference to FIG. FIG. 27 is a circuit diagram showing a signal transmission circuit according to the second embodiment.

  As in the first embodiment, the digital television 1 includes a signal transmission circuit SC2 at its input section. As shown in FIG. 27, the signal transmission circuit SC2 includes a common mode filter 10, an inductance element 20 having third and fourth inductors 21 and 22 that are magnetically coupled to each other, and first and second varistors 31. , 32 and fifth and sixth inductors 41, 42.

  The fifth inductor 41 has input / output terminals 43 and 44. The input terminal 43 of the fifth inductor 41 is connected to the output terminal 24 of the third inductor 21, and is electrically connected in series to the first inductor 11 and the third inductor 21. As a result, the fifth inductor 41 is positioned downstream of the first varistor 31.

  The sixth inductor 42 has input / output terminals 45 and 46. The input terminal 45 of the sixth inductor 42 is connected to the output terminal 26 of the fourth inductor 22, and is electrically connected in series to the second inductor 12 and the fourth inductor 22. As a result, the fifth inductor 42 is positioned downstream of the second varistor 32.

  As described above, in the second embodiment, since the fifth and sixth inductors 41 and 42 are inserted after the first and second varistors 31 and 32, respectively, the first and second varistors are provided. A decrease in characteristic impedance due to 31 and 32 can be further suppressed.

  As shown in FIGS. 7 to 9, the signal transmission circuit SC2 may be provided in the HDMI cable 3, the DVD player 2, or the connection terminal portions 5 and 6 (connectors). Even in this case, a decrease in characteristic impedance due to the first and second varistors 31 and 32 can be further suppressed.

  Subsequently, it will be specifically shown that the first and second embodiments of the signal transmission circuit can suppress a decrease in characteristic impedance caused by the first and second varistors. Here, the characteristic impedance of the signal transmission circuit is measured by a TDR (Time Domain Reflectometry) method. The TDR method is a measurement method for measuring the characteristic impedance of the transmission line by sending a step pulse to the transmission line and measuring the pulse reflected at the discontinuous portion of the characteristic impedance.

  First, the measurement environment by the TDR method will be described with reference to FIG. In each measurement environment shown in FIG. 28, a high-speed oscilloscope 50 and a receiver IC 52 are connected via a transmission line 54. The transmission path 54 includes a coaxial cable 56 and a signal transmission circuit 58. The high-speed oscilloscope 50 has a TDR module 51. The high-speed oscilloscope 50 is connected to the coaxial cable 56 through the TDR module 51, and the other end of the coaxial cable 56 is connected to the signal transmission circuit 58. A receiver IC 52 is connected to the other end of the signal transmission circuit 58.

  As the high-speed oscilloscope 50, an Agilent 86100 broadband oscilloscope manufactured by Agilent Technologies, Inc. is used. As the TDR module 51, a 54754 differential TDR plug-in module manufactured by Agilent Technologies is used. The receiver IC 52 has an infinite input impedance when the power is off, and 100% of the signal from the high-speed oscilloscope 50 is reflected. The coaxial cable 56 is composed of two differential signal lines, each having a characteristic impedance of 50Ω. For this reason, the characteristic impedance of the entire coaxial cable 56 is 100Ω.

  Next, a measurement method by the TDR method will be described based on FIGS. First, the high-speed oscilloscope 50 generates an incident voltage step Ei, and outputs this incident voltage step Ei to the transmission line 54. When there is no discontinuous characteristic impedance on the transmission line 54, the incident voltage step Ei is reflected by the receiver IC 52 as it is, and the high-speed oscilloscope 50 receives the incident voltage step Ei as shown in FIG. Only displayed. On the other hand, when a discontinuous portion exists in the characteristic impedance of the transmission line 54, a part of the incident voltage step is reflected at the discontinuous portion. In this case, as shown in FIG. 29B, the reflected wave Er is algebraically added to the incident voltage step Ei and displayed on the high-speed oscilloscope 50. From this result, the position of the characteristic impedance discontinuity and the value of the characteristic impedance can be obtained. That is, the position of the discontinuous part of the characteristic impedance can be obtained from the time T until the reflected wave Er is measured, and the characteristic impedance at the discontinuous part can be obtained from the value of the reflected wave Er.

  ACM2012D-900 (manufactured by TDK Corporation) was used as the common mode filter. The characteristic impedance of ACM2012D-900 is 100Ω. The cutoff frequency of ACM2012D-900 is 3.5 GHz. As the first and second varistors, AVR161A1R1 (manufactured by TDK Corporation) was used. The capacitance of AVR161A1R1 is 1.1 pF. The MLK1005 series (manufactured by TDK Corporation) was used for the third to sixth inductors.

  The measurement results are shown in FIGS.

  Refer to FIG. The characteristic I1 is a measurement result when the signal transmission circuit 58 includes the first and second varistors and does not include the common mode filter and the third to sixth inductors. As can be seen from the characteristic I1, the characteristic impedance is reduced under the influence of the first and second varistors, and impedance mismatch occurs.

  The characteristic I2 is a measurement result when the signal transmission circuit 58 includes the first and second varistors and the common mode filter, and does not include the third to sixth inductors. In configuring the signal transmission circuit 58, the distance on the transmission line between the output terminal of the common mode filter and the input terminals of the first and second varistors, that is, the output terminal of the common mode filter and the first and second varistors. The time length with respect to the input terminal was set to 23 ps.

  As can be seen from the characteristic I2, the characteristic impedance of the signal transmission circuit 58 is in the range of 100Ω ± 15%, but the characteristic impedance is still lowered due to the influence of the first and second varistors.

  Characteristics I3 to I5 indicate that the signal transmission circuit 58 includes the first and second varistors, the common mode filter, and the third and fourth inductors, that is, the signal transmission circuit 58 according to the first embodiment described above. It is a measurement result in the case of having the same configuration as the transmission circuit SC1. The characteristic I3 is a measurement result when the inductance values of the third and fourth inductors are 1.0 nH. Characteristic I4 is a measurement result when the inductance values of the third and fourth inductors are 1.5 nH. Characteristic I5 is a measurement result when the inductance values of the third and fourth inductors are set to 2.2 nH. In configuring the signal transmission circuit 58, the interval on the transmission line between the output terminal of the common mode filter and the input terminals of the third and fourth inductors, that is, the output terminal of the common mode filter and the third and fourth inductors. The time length with respect to the input terminal was set to 20 ps. Similarly, the distance on the transmission line between the output terminals of the third and fourth inductors and the input terminals of the first and second varistors, that is, the output terminals of the third and fourth inductors and the first and second output terminals. The time length between the varistor input terminals was set to 0 ps.

  As can be seen from the characteristics I3 to I5, a decrease in characteristic impedance due to the influence of the first and second varistors is suppressed.

  As can be seen from the characteristic I5, when the inductance values of the third and fourth inductors are set to 2.2 nH, the characteristic impedance is reduced at the positions of the first and second varistors, but at other places. The characteristic impedance becomes high. The occurrence of the portion where the characteristic impedance becomes high in this way is considered to be caused by the inductance values of the third and fourth inductors. Therefore, the inductance values of the third and fourth inductors are preferably 1 to 2 nH.

  Reference is now made to FIG. Characteristic I6 and characteristic I7 indicate that the signal transmission circuit 58 includes the first and second varistors, the common mode filter, and the third to sixth inductors, that is, the signal transmission circuit 58 according to the second embodiment described above. It is a measurement result in the case of the same configuration as the signal transmission circuit SC2. Characteristic I6 is a measurement result when the inductance values of the third to sixth inductors are set to 1.0 nH. Characteristic I7 is a measurement result when the inductance values of the third and fourth inductors are set to 1.0 nH and the fifth and sixth inductors are bypassed. In configuring the signal transmission circuit 58, the interval on the transmission line between the output terminal of the common mode filter and the input terminals of the third and fourth inductors, that is, the output terminal of the common mode filter and the third and fourth inductors. The time length with respect to the input terminal was set to 0 ps. Similarly, the distance on the transmission line between the output terminals of the third and fourth inductors and the input terminals of the first and second varistors, that is, the output terminals of the third and fourth inductors and the first and second output terminals. The time length between the varistor input terminals was set to 0 ps. Similarly, the distance between the input terminals of the first and second varistors and the input terminals of the fifth and sixth inductors on the transmission line, that is, the input terminals of the first and second varistors and the fifth and sixth varistors. The time length between the inductor input terminals was set to 0 ps.

  As can be seen from the characteristic I6, a decrease in characteristic impedance due to the influence of the first and second varistors is further suppressed.

  Reference is now made to FIG. The characteristics I8 to I10 indicate that the signal transmission circuit 58 includes the first and second varistors, the common mode filter, and the third to sixth inductors, that is, the signal transmission circuit 58 according to the second embodiment described above. It is a measurement result in the case of the same configuration as the transmission circuit SC2. Characteristic I8 is a measurement result when the inductance values of the third and fourth inductors are 1.5 nH and the inductance values of the fifth and sixth inductors are 1.0 nH. It is a measurement result in the case of. Characteristic I9 is a measurement result when the inductance values of the third to sixth inductors are 1.5 nH. The characteristic I10 is a measurement result when the inductance values of the third and fourth inductors are 1.5 nH and the fifth and sixth inductors are bypassed. In configuring the signal transmission circuit 58, the interval on the transmission line between the output terminal of the common mode filter and the input terminals of the third and fourth inductors, that is, the output terminal of the common mode filter and the third and fourth inductors. The time length with respect to the input terminal was set to 0 ps. Similarly, the distance on the transmission line between the output terminals of the third and fourth inductors and the input terminals of the first and second varistors, that is, the output terminals of the third and fourth inductors and the first and second output terminals. The time length between the varistor input terminals was set to 0 ps. Similarly, the distance between the input terminals of the first and second varistors and the input terminals of the fifth and sixth inductors on the transmission line, that is, the input terminals of the first and second varistors and the fifth and sixth varistors. The time length between the inductor input terminals was set to 0 ps.

  As can be seen from the characteristics I8 and I9, a decrease in characteristic impedance due to the influence of the first and second varistors is further suppressed.

  From the above, the usefulness of the signal transmission circuit according to the first and second embodiments was confirmed.

  As can be seen from the measurement results described above, the inductance values of the third to sixth inductors are preferably smaller than 10 nH, and more preferably 1 to 2 nH. This is because, as described above, a portion where the characteristic impedance increases due to the inductance values of the third to sixth inductors occurs, and impedance matching becomes insufficient.

  The distance on the transmission line between the output terminal of the common mode filter and the input terminals of the third and fourth inductors, and the transmission between the output terminals of the third and fourth inductors and the input terminals of the first and second varistors. The distance on the transmission line and the distance on the transmission line between the input terminals of the first and second varistors and the input terminals of the fifth and sixth inductors are preferably as short as possible. This is because the transmission line between the terminals (for example, the conductor pattern of the substrate) has an inductance component and a capacitance component, and these inductance component and capacitance component are factors that impede impedance matching.

  Note that when a common mode filter is used as a noise filter, a capacitor may be connected between signal lines (see, for example, Patent Document 2). However, when a capacitor is connected between the signal lines in the first and second embodiments of the signal transmission circuit, an unnecessary capacitance component is generated, and impedance matching cannot be achieved. Therefore, the first and second embodiments of the signal transmission circuit do not include a capacitor for connecting the signal lines.

  The preferred embodiments of the present invention have been described above, but the present invention is not necessarily limited to these embodiments. For example, the signal transmission circuits SC <b> 1 and SC <b> 2 are not limited to the positions described above, and may be provided before the first circuit of the digital television 1 after output from the DVD player 2. The DVD player 2 may be another source device such as a personal computer or a set top box. The HDMI cable 3 may be a cable that supports standards such as DVI, USB, and IEEE. The digital television 1 may be another sink device such as an LCD monitor or a projector.

  In the first and second embodiments of the signal transmission circuit, varistors are used as the first and second capacitive elements, but capacitive elements such as Zener diodes may be used as the first and second capacitive elements. Good.

  As the common mode filter 10, in addition to a wound common mode filter in which two insulated wires are wound around a ferrite core a plurality of times, a conductive pattern is formed using a laminated common mode filter or a thin film forming technique. A laminated common mode filter or the like may be used.

  In addition, in the inductance elements 60, 70, and 80 according to the second to fourth embodiments, the contact between the coils is prevented by the groove and the protrusion provided in the core 130, but the coils are provided in the core. Other shapes can be used as long as the contact between the coils can be prevented by the unevenness.

  Furthermore, in the inductance element 90 according to the fifth embodiment, the insulating films 131c and 132c are used to prevent the coils from contacting each other. However, the member interposed between the coils is limited to a film member as long as it is an insulator. It is not something. Therefore, for example, after one coil is wound, an ultraviolet curable resin or the like is applied and cured, and then the other coil is wound to prevent contact between the coils.

  The application range of the inductance elements 20, 60, 70, 80, 90 described as the first to fifth embodiments is not limited to the above-described signal transmission circuits SC1, SC2, and is used for other purposes. can do.

1 is a schematic diagram illustrating a signal transmission circuit according to a first embodiment. 1 is a circuit diagram illustrating a signal transmission circuit according to a first embodiment. FIG. It is a schematic diagram explaining operation | movement of a common mode filter. 1 is a schematic perspective view showing a structure of an inductance element 20 according to a first embodiment. (A) is a top view of the inductance element 20, and (b) is a side view of the inductance element 20. It is a figure for demonstrating the wiring pattern on the board | substrate which mounts the inductance element. It is a schematic diagram which shows the modification of the signal transmission circuit which concerns on 1st Embodiment. It is a schematic diagram which shows the modification of the signal transmission circuit which concerns on 1st Embodiment. It is a schematic diagram which shows the modification of the signal transmission circuit which concerns on 1st Embodiment. It is a schematic perspective view which shows the structure of the inductance elements 60 and 70 by 2nd and 3rd embodiment. (A) is a top view of the inductance element 60, and (b) is a bottom view of the inductance element 60. (A) is sectional drawing along the A1-A1 line of Fig.11 (a), (b) is sectional drawing along the B1-B1 line of FIG.11 (b). 6 is a process diagram for explaining a method of manufacturing the inductance element 60. FIG. 6 is a process diagram for explaining a method of manufacturing the inductance element 60. FIG. (A) is a top view of the inductance element 70 according to the third embodiment, and (b) is a bottom view of the inductance element 70 according to the third embodiment. (A) is sectional drawing along the A2-A2 line | wire of Fig.15 (a), (b) is sectional drawing along the B2-B2 line | wire of FIG.15 (b). 6 is a process diagram for explaining a method of manufacturing the inductance element 70. FIG. It is a schematic perspective view which shows the structure of the inductance element 80 by 4th Embodiment. (A) is a top view of the inductance element 80 according to the fourth embodiment, and (b) is a bottom view of the inductance element 80 according to the fourth embodiment. It is sectional drawing along the B3-B3 line | wire of Fig.19 (a). It is a schematic perspective view which shows the modification of protrusion part 131b, 132b. It is the front view and side view which show the modification of the core part. It is a top view which shows the state which wound the coil around the core part 130 by the modification. It is a schematic perspective view which shows the structure of the inductance element 90 by 5th Embodiment. 6 is a process diagram for explaining a method of manufacturing the inductance element 90. FIG. 6 is a process diagram for explaining a method of manufacturing the inductance element 90. FIG. It is a circuit diagram which shows the signal transmission circuit which concerns on 2nd Embodiment. It is a figure for demonstrating the measurement environment by TDR method. It is a figure for demonstrating the measuring method by TDR method. It is a diagram which shows the measurement result by TDR method. It is a diagram which shows the measurement result by TDR method. It is a diagram which shows the measurement result by TDR method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Digital television, 2 ... DVD player, 3 ... HDMI cable, 5, 6 ... Connection terminal part, 10 ... Common mode filter, 11 ... 1st inductor, 12 ... 2nd inductor, 21 ... 3rd inductor, DESCRIPTION OF SYMBOLS 22 ... 4th inductor, 31 ... 1st varistor, 32 ... 2nd varistor, 41 ... 5th inductor, 42 ... 6th inductor, SC1, SC2 ... Signal transmission circuit 20,60,70,80 , 90 ... inductance elements, 91 to 94 ... signal lines, 110 ... drum cores, 121 ... first coil, 121a ... one end of the first coil, 121b ... other end of the first coil, 122 ... second Coil, 122a ... one end of the second coil, 122b ... the other end of the second coil, 130 ... the core portion, 131 ... the top surface of the core portion, 132 ... the bottom surface of the core portion, 131a, 132a ... 131b, 132b ... projection, 131c, 132c ... insulating film, 131x ... recess, 131y ... guide, 138, 139 ... corner, 138a, 139a ... slit, 141 ... first collar, 142 ... second 151 ... First terminal electrode, 152 ... Second terminal electrode, 153 ... Third terminal electrode, 154 ... Fourth terminal electrode, 190 ... Substrate

Claims (9)

A drum core having a core part and first and second flanges provided at both ends of the core part;
First and second terminal electrodes formed on the first flange;
Third and fourth terminal electrodes formed on the second flange;
The winding core is wound in a predetermined direction from one end to the other end, the one end is connected to the first terminal electrode, and the other end is connected to the third terminal electrode. Coils,
The winding core is wound in a direction different from the predetermined direction from one end to the other end, the one end is connected to the second terminal electrode, and the other end is connected to the fourth terminal electrode. An inductance element comprising: the second coil formed.   The inductance element according to claim 1, wherein the first coil and the second coil intersect at a plurality of locations.   3. The inductance element according to claim 2, wherein the number of crossings between the first coil and the second coil is greater than the number of turns of the first coil and the number of turns of the second coil.   The inductance element according to claim 3, wherein the number of crossings is equal to the sum of the number of turns of the first coil and the number of turns of the second coil.   5. The apparatus according to claim 1, further comprising a separation unit that separates the first coil and the second coil in an intersecting region between the first coil and the second coil. The inductance element according to item.   The inductance element according to claim 5, wherein the separation unit is configured by unevenness provided in the core portion.   The concave and convex portions are a first portion for allowing the first coil to pass over the second coil while being spaced apart from each other, and for allowing the second coil to pass over the first coil while being spaced apart from each other. The inductance element according to claim 6, further comprising a second portion.   6. The inductance element according to claim 5, wherein the separation means is an insulator provided between the first coil and the second coil. First and second inductors magnetically coupled to each other;
A first capacitive element located downstream of the first inductor and electrically connected in parallel to the first inductor;
A second capacitive element located downstream of the second inductor and electrically connected in parallel to the second inductor;
The inductance element according to any one of claims 1 to 8, which is connected between the first and second inductors and the first and second capacitive elements,
The first and second terminal electrodes of the inductance element are connected to the first and second inductors, respectively, and the third and fourth terminal electrodes of the inductance element are the first and second terminals, respectively. A signal transmission circuit connected to the capacitive element.

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