EMI filter device

Abstract

EMI filter device (10) comprising: a signal processor (110) configured to output a predetermined signal and to output a noise source generated in a circuit;and a coil device (120) for removing the noise source, wherein the coil device (120) has a common-mode coil, a first coil (410) and a second coil (420) on a core, wherein the first coil (410) and the second coil (420) are electrically connected to each other, wherein the first coil (410) is mounted on a substrate having a first surface (510) and a second surface (520) which are arranged opposite each other, and the second coil (420) is mounted on a substrate having a third surface (530) and a fourth surface (540) which are arranged opposite each other, wherein the first coil (410) is mounted such that it connects the first surface (510) and the second surface (520) to each other, and the second coil (420) is mounted such that it connects the third surface (530) and the fourth surface (540) to each other.

Description

CROSS-REFERENCE TO LINKED REGISTRATION

[0001] This application claims priority over Korean patent application No. 10-2021-0116893, filed on September 2, 2021, which is hereby incorporated by reference into the present application for all purposes as if it were fully set forth herein. TECHNICAL AREA

[0002] The embodiments of the present disclosure relate to a filter device for electromagnetic interference (EMI filter device).

[0003] Since switching technology is developed and applied for almost all power electronic devices, the technology of EMI filtering (filtering of electromagnetic interference) is particularly important.

[0004] The conductive EMI component is divided into the common-mode (CM) component and the differential-mode (DM) component, and a passive filter can separate and filter the CM and DM components. Most conductive noise components of electrical / electronic devices that act as switching devices, such as a switched-mode power supply (SMPS), can appear in the form of a square wave and may be composed of harmonic components of a switching frequency.

[0005] Conventional active EMI filters can employ a method where a CM filter and a DM filter are used separately and in series to remove the noise of the CM component and the DM component, respectively. Consequently, a problem can arise in that the weight and volume of the EMI filter are increased, and its electrical properties are thereby degraded. SUMMARY

[0006] In this context, the present disclosure can provide an EMI filter device which removes differential-mode choke noise using a common-mode coil.

[0007] In one aspect of the present disclosure, an EMI filter device is provided, comprising a signal processor configured to output a predetermined signal and to output a noise source generated in a circuit, and a coil device for removing the noise source, wherein the coil device has a common-mode coil, a first coil and a second coil on a core, and wherein the first coil and the second coil are electrically connected to each other.

[0008] In accordance with embodiments of the present disclosure, the EMI filter device can use a single coil for common-mode and differential-mode noise, thereby achieving device commonality, which reduces costs and maximizes device performance. List of characters

[0009] The Fig. 1A and Fig. 1B are diagrams illustrating a method for reducing general common-mode noise and differential-mode noise. Fig. Figure 2 is a block diagram illustrating an EMI filter device in accordance with an embodiment of the present disclosure. Fig. Figure 3 is a circuit diagram which represents an EMI filter in accordance with an embodiment of the present disclosure. The Fig. 4A and Fig. Figure 4B contains diagrams to illustrate that a first coil and a second coil are electrically connected in accordance with an exemplary embodiment. Fig. Figure 5 is a diagram to illustrate that a first coil and a second coil are implemented on a substrate in accordance with one embodiment. Fig. Figure 6 is a diagram to illustrate that a first coil and a second coil are implemented in accordance with an embodiment on a multilayer printed circuit board. DETAILED DESCRIPTION

[0010] In the following description of examples or embodiments of the present disclosure, reference is made to the accompanying drawings, which show specific examples or embodiments that can be implemented for illustrative purposes and in which the same reference numerals and symbols may be used to designate the same or similar components, even if these are shown in different accompanying drawings. Furthermore, in the following description of examples or embodiments of the present disclosure, detailed descriptions of well-known functions and components included herein are omitted where it has been found that the description would make the subject matter of the invention rather unclear in some embodiments of the present disclosure.The terms used herein, such as "comprehensive," "exhibiting," "containing," "consisting of," "made of," and "formed of," are generally intended to allow the addition of other components, unless the terms are used with the qualifier "only" or "exclusively." As used herein, singular forms are intended to include plural forms unless the context clearly refers to the singular.

[0011] Terms such as "first," "second," "A," "B," "(A)," or "(B)" may be used herein to describe elements of the revelation. None of these terms are used to define the meaning, order, sequence, or number of elements, etc., but serve solely to distinguish the element in question from other elements.

[0012] When it is mentioned that a first element is "connected or coupled" to a second element, or that it "contacts or overlaps," this is to be interpreted as meaning that the first element can not only be "directly connected or coupled" to the second element, or that it "directly contacts or overlaps," but that a third element can also be "arranged" between the first and second elements, or that the first and second elements can be "connected or coupled" via a fourth element, or that they can "contact or overlap" via such a fourth element, etc. In this context, at least one of two or more elements that are "connected or coupled" or that "contact or overlap" etc. can include the second element.

[0013] When time-dependent terms, such as "afterwards", "subsequently", "next", "before", and the like, are used to describe processes or operations of elements or configurations, or sequences or steps of operational, processing, or manufacturing procedures, these terms may be used to describe non-consecutive or non-sequential processes or operations, provided they are not used together with the term "directly" or "immediately".

[0014] Furthermore, if arbitrary dimensions, relative sizes, etc., are specified, it must be taken into account that numerical values ​​for elements or characteristics, or corresponding information (e.g., level, range, etc.), have a tolerance or error range which can be caused by a wide variety of factors (e.g., process factors, internal or external influences, noise, etc.), even if a corresponding description is not explicitly provided. Moreover, the term "can / might / might" encompasses all meanings of the term "can."

[0015] The Fig. 1A and Fig. 1B are diagrams illustrating a method for reducing general common-mode noise and differential-mode noise.

[0016] Referring to the Fig. 1A and Fig. 1B Conductive and radiated noise is generated in a power module or control module found in an electrical vehicle system and general household appliances. This generated noise can cause interference with other electronic devices, leading to significant malfunctions or a degradation of device performance. To reduce or eliminate this noise, it can be divided into common-mode and differential-mode noise according to its phase, and each of these noise components can then be eliminated by a different method.

[0017] A common-mode coil of Fig. 1A generates a magnetic field of the same strength and phase while the common-mode current flows in the same direction, and since the common-mode coil can have a high resistance to the common-mode signal, the common-mode coil can accordingly suppress noise by damping the flow of the common-mode signal.

[0018] In contrast, in a push-pull coil of Fig. 1B Differential-mode signals pass through the windings of the differential-mode coil in opposite directions, creating magnetic fields of the same magnitude and opposite polarity that cancel each other out. Since the differential-mode coil can have a resistance of nearly zero with respect to the differential-mode signal, it can thus transmit the signal without attenuation.

[0019] To reduce both common-mode and differential-mode noise, it is necessary to increase the size of each coil or to increase the number of coils. In this case, the size and price of the EMI filter may increase.

[0020] An EMI filter device 10 in accordance with an embodiment of the present disclosure with reference to the accompanying drawings is described below, which is used in parallel to remove common-mode and differential-mode noise with a coil.

[0021] Fig. Figure 2 is a block diagram illustrating an EMI filter device 10 in accordance with an embodiment of the present disclosure, and Fig. Figure 3 is a circuit diagram which represents an EMI filter device 10 in accordance with an embodiment of the present disclosure.

[0022] Referring to Fig. 2 The EMI filter device 10 may, in accordance with an embodiment of the present disclosure, comprise a signal processor 110 and a coil device 120.

[0023] The signal processor 110 can output a predefined signal and can output a noise source generated within the circuit. For this purpose, the signal processor 110 can include a signal generator. Furthermore, the noise source can be generated by a battery that powers the electronic device. In a situation where external power is supplied to both ends of the signal processor 110, the noise source can also be noise present in a power supply / network. Instead of a specific device, the noise source can, for example, be conductive noise or radiated noise generated in an electronic device such as a signal generator.

[0024] Referring to Fig. 3. The coil device 120 can be connected in series with the signal processor 110 to eliminate a noise source. The coil device 120 can have a common-mode coil comprising a first coil 410 and a second coil 420, and the first coil 410 and the second coil 420 can be electrically connected. This means that the first coil 410 and the second coil 420 can function as one coil, as shown in Fig. 3 shown.

[0025] In one embodiment, a load can be connected in series with the first coil 410 and the second coil 420, and after the noise present in the current has been removed by the coil described above, the current can be supplied to the load.

[0026] In one embodiment, the coil type used in the common-mode coil can correspond to one of the types from the group comprising a toroidal type with high magnetic permeability, a UU type (UU-9.8, UU-10.5, etc.), an ET type and a UT type.

[0027] The first coil 410 and the second coil 420 can each have the form of windings wound around the core, but are not limited to this, and at least one of the coils in the group comprising the first coil 410 and the second coil 420 can have a structure passing through the core.

[0028] The Fig. 4A and Fig. Figure 4B shows diagrams illustrating that a first coil 410 and a second coil 420 are electrically connected in accordance with an exemplary embodiment.

[0029] In one embodiment, the first coil 410 and the second coil 420 can be wound by a coil.

[0030] Fig. 4A represents a general common-mode coil, and in the present disclosure an EMI filter can be designed by adapting the winding method of the common-mode coil of Fig. 4A into that of Fig. 4B is changed.

[0031] Referring to Fig. 4B the coils can be wound as one coil in which the point 'a' in Fig. 4, where the winding of the first coil 410 ends, and the point 'b' in Fig. 4B, where the winding of the second coil 420 begins, are connected together. In the case where the coil has been wound by the method described above, the coil has the effect of eliminating differential-mode noise. In addition, the coil device can further include a capacitor X, which is connected in parallel with the first coil 410 and the second coil 420, in order to eliminate differential-mode noise.

[0032] The EMI filter device 10 described above can be implemented on a printed circuit board (PCB).

[0033] Fig. Figure 5 is a diagram to illustrate that a first coil 410 and a second coil 420 are implemented on a substrate in accordance with an embodiment.

[0034] Referring to Fig. 5. The first coil 410 and the second coil 420 can be mounted on substrates having a first surface 510 and a second surface 520 facing each other, or a third surface 530 and a fourth surface 540 facing each other. The first coil 410 can be mounted on a substrate having the first surface 510 and the second surface 520 facing each other, and the second coil 420 can be mounted on a substrate having the third surface 530 and the fourth surface 540 facing each other. Furthermore, the first coil 410 can be mounted such that it connects the first surface 510 and the second surface 520, and the second coil 420 can be mounted such that it connects the third surface 530 and the fourth surface 540.

[0035] Furthermore, to eliminate differential-mode noise with a common-mode coil, the second surface 520 and the third surface 530 can be electrically connected to each other, as shown in Fig. Figure 5 shows that the current can flow in the printed circuit board by tracing a Z-shape in the sequence from the first surface 510, through the second surface 520 and the third surface 530, to the fourth surface 540. Furthermore, the first surface 510 and the second surface 520 can be located in an upper section of the third surface 530 and the fourth surface 540.

[0036] Fig. Figure 6 is a diagram to illustrate that a first coil 410 and a second coil 420 are implemented in accordance with an embodiment on a multilayer printed circuit board.

[0037] Referring to Fig. 6. The EMI filter device 10 can be implemented in accordance with an embodiment of the present disclosure in the multilayer printed circuit board described above. To illustrate the connection between the first coil 410 and the second coil 420 with a printed conductive surface composed of four layers, each of the coils can, for example, be mounted in a PCB structure printed on each of the layers and in a hole formed on the PCB structure.

[0038] The positions of the holes formed in each layer can be the same. This means that the position of the hole formed in the first layer can be the same as the position of the hole formed in the second layer.

[0039] If the first coil 410 and the second coil 420 are connected to each other, then, as shown in Fig. Figure 6 shows that in the first and fourth layers the first surface 510 and the second surface 520, respectively the third surface 530 and the fourth surface 540, are connected to each other by the first coil 410 and the second coil 420, respectively.

[0040] Furthermore, to electrically connect the first coil 410 and the second coil 420, a PCB structure can be formed in the second and third layers, as shown in Fig.Figure 6 shows that in the second and third layers, the second surface 520 and the third surface 530 can be electrically connected to each other by a PCB structure formed on the second surface 520 and the third surface 530. In one embodiment, the EMI filter device 10 can be implemented by a separate device for connecting the coil terminals, which are exposed on the surface of the printed circuit board on which the common-mode coil is mounted. In contrast to a design in which the first coil 410 and the second coil 420 are connected to each other by an internal structure of the printed circuit board, as in the multilayer printed circuit board described above, the first coil 410 and the second coil 420 are not connected to each other by an internal structure of the printed circuit board.

[0041] As described above, the EMI filter device 10 can remove two types of noise using a single type of choke coil.

[0042] Furthermore, if the winding or turn of the general common-mode coil is used, it is possible to ensure a sufficient LDM value according to the following equation 1, since the L value can be used in a frequency corresponding to the Nth number of turns. L=N2Rm=μSN2l (L∝N2)

[0043] The above description has been set forth to enable all persons skilled in the art to implement and use the technical idea of ​​this disclosure and has been provided in connection with a specific application and its requirements. Various modifications, additions, and substitutions of the described embodiments are readily apparent to trained professionals, and the general principles defined herein can be applied to other embodiments and applications without departing from the intent and scope of this disclosure. The above description and the accompanying drawings provide an example of the technical idea of ​​this disclosure solely for illustrative purposes. This means that the disclosed embodiments are intended to illustrate the scope of the technical idea of ​​this disclosure.Therefore, the scope of the present disclosure is by no means limited to the embodiments shown; rather, it is to be considered to have the broadest scope in accordance with the claims. The scope of protection of the present disclosure is to be interpreted on the basis of the following patent claims, and all technical ideas within the scope of correspondences thereto are to be interpreted as being included in the scope of the present disclosure.

Claims

[1] EMI filter device, comprising: a signal processor configured to output a predetermined signal and a noise source generated in a circuit; and a coil device for removing the noise source, wherein the coil device comprises a common mode coil comprising a first coil and a second coil on a core, wherein the first coil and the second coil are electrically connected to each other. [2] The EMI filter device according to claim 1, wherein the first coil and the second coil are wound by one coil. [3] The EMI filter device according to claim 1, wherein the coil device further comprises a capacitor X for removing differential mode noise. [4] The EMI filter device according to claim 1, wherein the first coil is mounted on a substrate having a first surface and a second surface arranged opposite to each other, and the second coil is mounted on a substrate having a third surface and a fourth surface arranged opposite to each other, the first coil being mounted so as to connect the first surface and the second surface, and the second coil being mounted so as to connect the third surface and the fourth surface. [5] The EMI filter device according to claim 4, wherein the first surface and the second surface are arranged at an upper portion of the third surface and the fourth surface, and the second surface is electrically connected to the third surface. [6] The EMI filter device according to claim 4, wherein the substrate is a multilayer printed circuit board. [7] The EMI filter device according to claim 6, wherein in a first layer and in a fourth layer, the first surface and the second surface are connected to each other by the first coil, and the third surface and the fourth surface are connected to each other by the second coil, wherein, in a second layer and in a third layer, the second surface is electrically connected to the third surface.

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