JP4987506B2 - Inductance element and noise filter using the same - Google Patents

Description

  The present invention relates to an electrical component applied to an alternating current (AC) adapter mainly in a power supply circuit using a switching power supply circuit, and more particularly to noise attenuation with respect to an alternating current line (AC line) required for commercial power input. The present invention relates to an inductance element used for configuring a noise filter connected for the purpose and a noise filter using the inductance element.

  Conventionally, as this type of switching power supply circuit, for example, one having a circuit configuration as shown in FIG. 6 (which is not an invention according to publicly known literature but is generally known) can be cited.

  This switching power supply circuit includes an input side (primary side) filter unit 1, a primary side rectifier circuit unit 2, a switching element unit 3, a transformer unit 4, an output side (secondary side) rectifier circuit unit 5, and a secondary side smoother. A capacitor 6, a voltage change detection circuit unit 7, and a control circuit unit 8 are provided. Although the details are schematically shown here, each part includes a chip component such as a resistor, a capacitor, and a diode to constitute a circuit.

  Among these, the input side filter unit 1 is a noise filter connected for attenuation of noise with respect to an AC line required for commercial power input, and has a function of preventing noise from entering from the power input side. It works to suppress noise generated from the switching power supply and returning to the input power supply. The primary side rectifier circuit unit 2 rectifies an AC power supply from a commercial power supply with full waves or half waves. The switching circuit unit 3 performs on / off control of the rectified voltage based on the control signal given from the control circuit unit 8, and outputs an alternating voltage having a pulse width corresponding to the control signal at a predetermined frequency. The transformer unit 4 transforms the AC voltage from the switching circuit unit 3 input from the primary side into an AC voltage having a predetermined value and outputs the AC voltage from the secondary side. The secondary side rectifier circuit unit 5 rectifies the AC voltage output from the transformer unit 4 and outputs a pulsating voltage. The secondary side smoothing capacitor 6 smoothes the pulsating voltage from the secondary side rectifier circuit unit 5 and outputs it as a DC voltage. The voltage change detection circuit unit 7 detects a change in the DC voltage output from the secondary side smoothing capacitor 6 and outputs a detection signal. The control circuit unit 8 outputs a pulse width detection signal based on the detection signal from the voltage change detection circuit unit 7 so as to be a control signal having a predetermined frequency, and supplies it to the switching circuit unit 3.

  FIG. 7 is a circuit block diagram showing a detailed configuration on the commercial power supply input side in this switching power supply circuit. Here, the details of the circuit configuration of the input side filter unit 1 are mainly shown. However, the input side filter unit 1 itself has an inductance element 13, a capacitor element 12, and a differential mode as electrical components for removing common mode noise. It consists of an inductance element 11 as an electric component for removing the noise. Incidentally, the differential mode noise here refers to the noise generated between the input lines in the input side filter circuit unit 1, and the common mode noise is different from that between the two input lines in the input side filter circuit mail 1. This shows noise generated between the reference potential. In particular, the inductance element 13 has a basic structure in which a winding is wound around a toroidal magnetic core, and the winding needs to have a certain thickness because current also flows.

  FIG. 8 is a plan view showing a basic configuration of the inductance element 13 provided in the input-side filter unit 1 described above. The inductance element 13 has a generally known structure (see, for example, Patent Documents 1 and 2). The outer peripheral surface of the toroidal magnetic core 14 is covered with an insulating case 15, and the entire surface is circular. The windings 16 and 17 are wound along the circumferential direction, and the lead portions of the windings 16 and 17 are parallelly drawn out.

  Incidentally, the inductance element (filter element, communication transformer) having such a structure requires two windings in order to remove common mode noise. For this purpose, the number of windings is increased to some extent. There is a need. A switching power supply circuit as described above is always used for an electric product of a type that obtains electric power from a commercial power supply, and a noise filter (input side filter unit) is always required there.

JP 2004-235709 A (paragraphs [0013], [0014], [0018], [0028], FIG. 1, FIG. 5, FIG. 15) JP-A-2005-150198 (Summary, paragraphs [0004], [0040], [0041], [0056], [0065] to [0069], FIG. 1, FIG. 2, FIG. 5, FIG. 7, FIG. (Fig. 14)

  Due to the recent demand for smaller and thinner electrical products, the filter circuit on the input side of the switching power supply circuit is also required to be smaller, cheaper and have higher performance. Similarly, downsizing and high performance are required.

  However, an inductance element for removing common mode noise in the input side filter circuit section with the basic structure as shown in FIG. 8 (including the filter element and communication transformer of Patent Documents 1 and 2). As the current flows, it is necessary to make the windings thick to some extent and to increase the number of windings to some extent, and to increase the magnetic core in order to improve the amount of attenuation. The necessity increases the overall volume and makes it difficult to reduce the size. As a result, there is a problem in that both size reduction and high performance cannot be realized at low cost.

  This means that the inductance element itself has not been improved in consideration of the basic structure (overall structure) and the creepage distance of the winding to the magnetic core in the first place for several decades, and has a relatively large volume. In addition, there is a situation that the characteristic improvement as a filter remains stagnant for many years.

  The present invention has been made to solve such problems, and its technical problem is to provide a common mode inductance element that can be reduced in size and performance at low cost and a noise filter using the same. It is in.

According to the present invention, in the inductance element formed by winding the winding along the circumferential direction on the entire surface of the insulating case after covering the outer peripheral surface of the toroidal magnetic core with the insulating case, A copper foil as a foil-like conductor for capacitively coupling the winding to at least a part of the outer surface of the winding is provided so as to cover with an insulator interposed, and connected to the copper foil for ground connection An inductance element is obtained, characterized in that the terminals are drawn outwardly in parallel with and spaced from the lead portions of the winding at positions outside the plurality of lead portions of the winding.

  In addition, according to the present invention, in any one of the above-described inductance elements, an inductance element having a magnetic core permeability of 10,000 or more can be obtained.

  In any one of these inductance elements, it is preferable that a plurality of windings are magnetically coupled to each other by a magnetic core.

  On the other hand, according to the present invention, it is possible to obtain a noise filter having any one of the above inductance elements, in which the inductance element is connected to an AC line of a commercial power input.

  On the other hand, according to the present invention, a filter unit comprising any one of the above inductance elements and at least one capacitive element is obtained. The filter unit preferably comprises at least one additional inductance element.

  Further, an electric device including any one of the above inductance elements in the commercial power input unit is configured, and an electric device functioning as an AC line filter is configured including any one of the filter units in the commercial power input unit. A switching power supply comprising any one of the inductance elements in a commercial power supply input unit; and a switching power supply that functions as an AC line filter while providing any one of the filter units in the commercial power supply input unit. Configuring any one of the inductance elements in the voltage output unit to configure a switching power supply, and arranging any one of the filter units in the voltage output unit to configure the switching power supply. Each is preferred.

  In the case of the inductance element of the present invention, a foil-like conductor for capacitively coupling the winding wound around the magnetic core is provided so as to cover at least a part of the element with an insulator interposed therebetween, and connected to the foil-like conductor. Since the ground connection terminal is structured to be pulled out to the outside, the material is selected so that the magnetic core has a volume that is about ½ that of the conventional core and high magnetic permeability is obtained. Even if downsizing, excellent attenuation characteristics are obtained in the high frequency band, and the noise removal effect is increased. As a result, the overall downsizing and high performance can be achieved at a low cost. Effects can be obtained.

Inductance element according to an embodiment of the present invention, the basic structure formed by winding a magnetic Koahe windings, is interposed insulator foil-like conductors for capacitive coupling the windings against at least a portion of the element It is provided to cover.

  However, in this inductance element, the foil conductor preferably has a ground connection terminal connected so as to be drawn outward. In any case, the inductance element includes an insulating case that covers the outer surface of the magnetic core, an insulating bobbin for mounting the magnetic core and winding the winding, and a foil that can fix the magnetic core. This structure can be applied to the case where at least one of the insulating terminal blocks provided with the conductor is provided, and such a structure is also preferable. The foil conductor is preferably a copper foil, and the magnetic core preferably has a magnetic permeability of 10,000 or more. Furthermore, it is preferable that the winding is composed of a plurality of windings and is magnetically coupled to each other by a magnetic core.

  Any of the inductance elements is a noise filter having these elements, and can be applied as a noise filter in which the inductance element is connected to an AC line (AC line) of commercial power input. Incidentally, the noise filter referred to here is the input-side filter unit 1 in the switching power supply circuit shown in FIG. 6, and any inductance element is replaced with the common mode inductance element 13 shown in FIG. It is a substitute.

  Accordingly, in the following, some embodiments will be described, and the common mode inductance element for the input side filter portion for the switching power supply circuit of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a plan view showing a basic configuration of a common mode inductance element 13a according to the first embodiment of the present invention.

  The inductance element 13a has a basic structure in which the outer peripheral surface of the toroidal magnetic core 14a is covered with an insulating case 15a, and the windings 16 and 17 are wound around the entire surface along the circumferential direction. A copper foil 22 is provided as a foil-like conductor for capacitively coupling the windings 16 and 17 with respect to the local surface of the windings 16 and 17, and a ground connection terminal 21 connected to the copper foil 22 is wound. The lead wires 16 and 17 are parallel to and separated from the lead portions and are drawn outward.

  That is, in this inductance element 13a, the copper foil 22 having the ground connection terminal 21 is provided on a part of the outer surface of the windings 16 and 17 on the outer periphery of the element, and the windings 16 and 17 are covered by that part. When used in the above, it is necessary to provide a structure in which an insulating material is interposed between the windings 16 and 17 and the copper foil 22 to obtain capacitive coupling of the copper foil 22 to the windings 16 and 17.

In the case of the inductance element 13a according to Example 1, the magnetic core 14a used has an outer diameter of 10.85 mm, an inner diameter of 6.61 mm, a height of 1.67 mm, and a volume of 95 mm ³ . For comparison, the size of the magnetic core 14 used in the inductance element 13 described with reference to FIG. 8 has an outer diameter of 10.91 mm, an inner diameter of 5.87 mm, a height of 3.00 mm, and a volume of 199 mm ^3. Therefore, the volume of the magnetic core 14a is about ½ of the volume of the magnetic core 14. Further, the magnetic permeability of the magnetic core 14 a is about twice the magnetic permeability of the magnetic core 14.

  Therefore, the attenuation characteristics with respect to frequency in the inductance element 13a according to the first embodiment and the known inductance element 13 were compared.

  FIG. 2 shows the attenuation Mag (dB) characteristics with respect to the frequency (MHz) of the inductance element 13a, in comparison with that of the conventional inductance element 13 shown in FIG.

  From the comparison result of the attenuation characteristics, it can be seen that the inductance element 13a according to the first embodiment exceeds that of the inductance element 13 in the frequency band of 30 kHz to about 60 MHz.

  In particular, the attenuation characteristic of the inductance element 13a according to the first embodiment exceeds the attenuation characteristic of the conventional inductance element 13 on the low frequency band side because the permeability of the magnetic core 14a used is the permeability of the magnetic core 14. 2 times larger than the above, largely due to the difference in material properties. Further, the attenuation characteristic of the inductance element 13a greatly exceeds the attenuation characteristic of the inductance element 13 up to the frequency band of 1 MHz to 60 MHz. By covering and grounding from the copper foil 22 with the ground connection terminal 21, it is considered that the self-line capacitance of the windings 16 and 17 is canceled and the high frequency characteristics are improved, resulting in a difference in basic structure. .

  Incidentally, in the inductance element 13a according to the first embodiment, the locations and areas of the windings 16 and 17 that are covered with the copper foil 22 are the number of turns (the number of turns), the thickness, The length can be changed as appropriate depending on the size, size of the magnetic core 14a, material characteristics, and the like.

  FIG. 3 is a plan view partially showing the basic configuration of the common mode inductance element 13b according to the second embodiment of the present invention.

  The inductance element 13b has a basic structure in which the outer peripheral surface of the toroidal magnetic core 14b is covered with an insulating case 15b, and the entire surface thereof is wound with the windings 16 and 17 along the circumferential direction. The copper foil 23 is provided as a foil-like conductor for capacitively coupling the windings 16 and 17 to the local portion of the insulating case 15b, and the ground connection terminal 21 connected to the copper foil 23 is connected to the windings 16, The structure is such that it is parallel to the lead portion of 17 and is drawn outward.

  That is, the inductance element 13b has a structure in which the copper foil 23 having the ground connection terminal 21 is provided in a part of the insulating case 15b that is a local part inside the element outer peripheral side, and the windings 16 and 17 are covered by the part. In this case, however, the copper foil 23 can be disposed on the inner side of the insulating case 15b, or the copper foil 23 can be disposed on the outer surface of the magnetic core 14b. In any case, the copper foil 23 is provided with an insulating case 15b, which is an insulator, and the windings 16 and 17 can be covered with the copper foil 23. Therefore, a creeping distance from the windings 16 and 17 is also ensured. It has a convenient structure in that it can be done.

  Also in the inductance element 13b according to the second embodiment, the attenuation characteristic is higher than that of the conventional inductance element 13 as in the first embodiment shown in FIG. It will be possible. Incidentally, also in the case of the inductance element 13b according to the second embodiment, the location and area of the windings 16 and 17 covered with the copper foil 23 are the number of turns (the number of turns) of the windings 16 and 17 being wound. , Thickness, length, size of the magnetic core 14b, material characteristics, etc.

  FIG. 4 is a plan view showing a basic configuration of a common mode inductance element 13c according to the third embodiment of the present invention.

  The inductance element 13c has a basic structure in which the outer peripheral surface of the toroidal magnetic core 14c is covered with an insulating case 15c, and the windings 16 and 17 are wound around the entire surface along the circumferential direction. A copper foil 24 is provided as a foil-like conductor for capacitive coupling so as to cover the windings 16 and 17 on the inner peripheral side of the element, and a ground connection terminal 21 connected to the copper foil 24 is connected to the windings 16 and 17. The structure is parallel to the lead part and pulled out to the outside.

That is, in this inductance element 13c, a copper foil 24 having a ground connection terminal 21 is provided on a part of the inner peripheral surface of the element and the windings 16 and 17 are covered by that part. In this case, it is necessary to provide a structure for obtaining capacitive coupling between the windings 16 and 17 of the copper foil 24 by interposing an insulator between the windings 16 and 17 and the copper foil 24. For example, as shown in FIG. 4, it is necessary to devise a way of drawing (lead wire drawing pattern) such as approaching the lead portion of the winding 17.

  In the inductance element 13c according to the third embodiment, the attenuation characteristic is higher than that of the conventional inductance element 13 as in the first embodiment shown in FIG. It will be possible. Incidentally, also in the case of the inductance element 13c according to the third embodiment, the location and area of the windings 16 and 17 covered with the copper foil 24 are the number of turns (the number of turns) of the windings 16 and 17 being wound. , Thickness, length, the size of the magnetic core 14c, material characteristics, and the like. Further, as in the case of the second embodiment, a structure in which a copper foil is disposed in the core case on the inner peripheral side of the element can be employed.

  FIG. 5 is a plan view partially showing the basic configuration of the common mode inductance element 13d according to the fourth embodiment of the present invention.

  The inductance element 13d has a basic structure in which the outer peripheral surface of the toroidal magnetic core 14d is covered with an insulating case 15d, and the entire surface is wound with windings 16 and 17 along the circumferential direction. An insulating terminal block 26 in which copper foil 25 is embedded as a foil-like conductor for capacitively coupling the windings 16 and 17 to the local area of the outer peripheral surface of the element is attached to fix the magnetic core 14d, and to insulate The ground connection terminal 21 connected to the copper foil 25 in the terminal block 26 is drawn out in parallel between the lead portions of the windings 16 and 17.

  That is, in this inductance element 13d, a copper foil 25 having a ground connection terminal 21 is embedded in an insulating terminal block 26 attached to the element as a separate component, and the windings 16 and 17 are covered with this portion. In this case, since the copper foil 25 can be provided with the insulating case 15d and the insulating terminal block 26 interposed therebetween, the creeping distance between the windings 16 and 17 can be ensured with higher accuracy as in the third embodiment. This is an advantageous structure.

  The inductance element 13d according to the fourth embodiment also has a higher performance than that of the conventional inductance element 13 as in the first embodiment shown in FIG. In addition, the overall size can be reduced. Incidentally, also in the case of the inductance element 13d according to the fourth embodiment, the locations and areas of the windings 16 and 17 that are covered with the copper foil 25 embedded in the insulating terminal block 26 are the windings 16 that are wound. , 17 can be appropriately changed according to the number of turns (number of turns), thickness, length, size of the magnetic core 14d, material characteristics, and the like.

  In the inductance elements 13a to 13d according to the above-described embodiments, the structure in which the outer surfaces (outer peripheral surfaces) of the magnetic cores 14a to 14d are covered with the insulating cases 15a to 15d has been described. It is possible to change to a structure in which the insulative bobbin windings 16 and 17 are wound using an insulative bopin on which the body cores 14a to 14d can be mounted. Since the high performance with excellent attenuation characteristics can be achieved, the inductance element of the present invention is not limited to those disclosed in the embodiments. In any case, when the inductance element of the present invention is applied to a noise filter, it can contribute to miniaturization and high performance equally.

  By the way, in the case of the inductance element described above, the windings 17 and 18 are composed of a plurality of pieces and can be structured to be magnetically coupled to each other by the magnetic cores 15a to 15d. Thus, the inductance element described above can be applied to various fields. For example, if at least one capacitive element is combined with such an inductance element, or a structure including at least one other inductance element is provided, the filter unit can be applied. Moreover, if such an inductance element is provided in the commercial power input section, it can be applied as an electric device. In this case, in particular, when the filter unit having the above-described configuration is provided in the commercial power supply input unit, an electric device that functions as an alternating current (AC) line filter can be manufactured. Furthermore, if such an inductance element is provided in the commercial power input section, it can be applied as a switching power supply. In this case as well, a switching power supply device that functions as an alternating current (AC) line filter can be manufactured by providing the filter unit having the above-described configuration in the commercial power supply input unit. In addition, if such an inductance element is arranged in the voltage output unit, it can be applied as a switching power supply device. In this case, it is particularly preferable to construct the switching power supply device by arranging the filter unit having the above-described configuration in the voltage output unit.

It is the top view which showed the basic composition of the inductance element which concerns on Example 1 of this invention. FIG. 3 shows the attenuation characteristics with respect to frequency in the inductance element shown in FIG. 1 in comparison with that of a conventional inductance element. It is the top view which looked through and showed the basic composition of the inductance element which concerns on Example 2 of this invention. It is the top view which showed the basic composition of the inductance element which concerns on Example 3 of this invention. It is the top view which showed a part transparent structure of the basic composition of the inductance element concerning Example 4 of the present invention. It is a circuit block diagram showing a basic configuration of a conventional switching power supply circuit. FIG. 7 is a circuit block diagram showing a detailed configuration on the commercial power input side in the switching power supply circuit shown in FIG. 6. It is the top view which showed the basic composition of the inductance element with which the input side filter part shown by FIG. 7 is equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input side filter part 2 Primary side rectifier circuit part 3 Switching circuit part 4 Transformer part 5 Secondary side rectifier circuit part 6 Secondary side capacitor 7 Voltage change detection part 8 Control circuit controller 11, 13, 13a-13d Inductance element 12 Capacitor element 14, 14a-14d Magnetic core 15, 15a-15d Insulating case 16, 17 Winding 21 Ground connection terminal 22-25 Copper foil 26 Insulating terminal block

Claims (12)

In an inductance element formed by covering the outer peripheral surface of a toroidal-shaped magnetic core with an insulating case and winding the winding along the circumferential direction on the entire surface of the insulating case, the outer surface of the winding A copper foil as a foil-like conductor for capacitively coupling the winding to at least a part of the winding is provided so as to cover with an insulator interposed, and a ground connection terminal connected to the copper foil includes the winding An inductance element, wherein the inductance element is drawn outward at a position outside the plurality of lead portions in parallel with and spaced from the lead portions of the winding.   2. The inductance element according to claim 1, wherein the magnetic core has a magnetic permeability of 10,000 or more.   3. The inductance element according to claim 1, wherein the winding includes a plurality of windings and is magnetically coupled to each other by the magnetic core. 4.   A noise filter comprising the inductance element according to claim 1, wherein the inductance element is connected to an AC line of a commercial power input.   A filter unit comprising the inductance element according to claim 1 and at least one capacitive element.   6. The filter unit according to claim 5, further comprising at least one other inductance element.   An electric device comprising the inductance element according to claim 1 in a commercial power supply input unit.   An electric device comprising the filter unit according to claim 5 or 6 in a commercial power input unit and functioning as an AC line filter.   A switching power supply comprising the inductance element according to claim 1 in a commercial power input section.   A switching power supply comprising the filter unit according to claim 5 or 6 in a commercial power supply input unit and functioning as an AC line filter.   A switching power supply device comprising: the inductance element according to claim 1 disposed in a voltage output unit.   7. A switching power supply device comprising the filter unit according to claim 5 or 6 disposed in a voltage output unit.

Images