Noise filter

Abstract

To provide a noise filter that is particularly applicable to a three-phase system and includes a choke coil having a non-circular magnetic core, which has a large inner diameter that allows the winding positions of the winding sets to be spaced a certain distance apart, thereby solving the wiring problems of the circuit board that existed in the prior art.SOLUTION: In a noise filter 4, at least three capacitors 31 are provided on a circuit board 3. The choke coil 2 is disposed on the circuit board and includes a non-circular magnetic core 21 and at least three winding sets 22 wound around the non-circular magnetic core. The at least three capacitors are provided adjacent to the choke coil, and first output ends 22a of the winding sets are connected to correspond to the at least three capacitors.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a noise filter, and more particularly to a noise filter applicable to a three-phase system and including a choke coil having a non-circular magnetic core.

Background Art

[0002] With the progress and development of science and technology, various electrical appliances are very common and frequently used. In the use of electrical appliances, in order to operate the electrical appliances normally, it is inevitable to use a power source. However, when it is necessary to use an AC power source for the operation of an electrical appliance, noise current may be mixed in the current supplied from the AC power source due to the power supply, the operation of the parasitic capacitance or stray capacitance of a high-frequency transformer or other components, which is the electromagnetic interference (EMI) phenomenon.

[0003] Generally, the noise generated by the use of an AC power source includes differential mode noise and common mode noise. The electromagnetic interference filter can function as the first line of defense against the electromagnetic radiation of the power source. The electromagnetic interference filter is mainly composed of a choke coil and a capacitor. The choke coil is an inductive component for suppressing the generation of noise and is usually composed of at least one winding set, a group of magnetic cores, and a winding frame for winding the winding set.

[0004] FIG. 1A and FIG. 1B are schematic views showing a conventional electromagnetic interference choke coil from different angles. As shown in FIG. 1A and FIG. 1B, the conventional choke coil 1 usually includes a circular magnetic core 11 having a hollow portion and a plurality of coils 12, and the plurality of coils 12 are wound around the hollow circular magnetic core 11.

[0005] Generally, in order to increase the inductance of the conventional choke coil 1, it is usually necessary to increase the number of turns of the coil 12. However, as can be seen from FIG. 1B, the inner diameter of the circular magnetic core 11 is constant, that is, it means that the space of the hollow part of this circular magnetic core 11 is limited. Therefore, in this prior art, only three sets of coils 121, 122, and 123 can be wound. In other words, even if we try to further increase the number or the number of turns of the coil 12 to increase the inductance, it is limited by the inner diameter of the circular magnetic core 11, and it is difficult to increase the number or the number of turns of the coil 12 any further.

[0006] Also, since the central part of the inner diameter of this circular magnetic core 11 is relatively small (that is, the space of the hollow part of the circular magnetic core 11 is relatively small), when a large current flows through the coil 12, the choke coil 1 may have difficulty in wiring on the circuit board 3 (as shown in FIG. 1C) due to the problem of the safety distance between the coils 12, which may affect its layout. For example, as shown in FIG. 1A, since the distance between the pins 121a and 122a of the coils 121 and 122 wound around the circular magnetic core 11 is too close, when it is arranged on the circuit board 3 as shown in FIG. 1C, wiring becomes difficult due to the problem of the safety distance between the pins 121a and 122a. Also, as can be seen from FIG. 1C, since the three sets of coils 12 are wound in a diagonal arrangement with respect to each other, the lead-out positions where some of the pins 121a, 122a, etc. are installed on the circuit board 3 may have an irregular inclination angle (that is, not in the horizontal or vertical position), which may affect the installation positions and the number of other electronic components 30 or capacitors 31 on the circuit board 3, making the design of the circuit board 3 difficult.

[0007] Furthermore, in other prior arts, in order to solve problems such as the inductance and the safety distance of the conventional choke coil 1, it is necessary to adopt a circular magnetic core 11 with a larger size so as to increase the inductance and satisfy the safety distance. In this way, the volume of the conventional choke coil 1 becomes large, and the volume of the product also becomes large, resulting in the problem that the electronic device cannot be miniaturized.

[0008] Therefore, how to develop a noise filter that can improve the problems faced by the above-mentioned prior art is one of the important issues.

Summary of the Invention

Problems to be Solved by the Invention

[0009] An object of the present invention is to provide a noise filter, particularly a noise filter applicable to a three-phase system and including a choke coil having a non-circular magnetic core. Due to the large inner diameter of the non-circular magnetic core, the winding positions of the winding sets can be separated by a certain distance, and the wiring problems of the circuit board in the prior art can be solved.

[0010] Another object of the present invention is to provide a noise filter including a choke coil having a non-circular magnetic core, which can effectively increase the space utilization rate of the circuit board, reduce the volume of the entire device, increase the inductance, or shunt the current to reduce the loss by flexibly adjusting the number and position of capacitors on the circuit board according to the form of the non-circular magnetic core, the winding positions of at least three or more winding sets, and the series and parallel methods.

Means for Solving the Problems

[0011] According to the concept of the present invention, the present invention provides a noise filter including a circuit board and a choke coil. At least three or more capacitors are provided on the circuit board. The choke coil is installed on the circuit board and includes a non-circular magnetic core and at least three or more winding sets wound around the non-circular magnetic core. At least three or more capacitors are provided adjacent to the choke coil, and the first lead-out end of the winding set is connected corresponding to at least three or more capacitors.

[0012] According to the concept of the present invention, the non-circular magnetic core has a hollow portion, and when at least three or more winding sets are wound around the non-circular magnetic core, a part of the winding set passes through the hollow portion of the non-circular magnetic core.

[0013] According to the concept of the present invention, the non-circular magnetic core is an elliptical annular magnetic core.

[0014] According to the concept of the present invention, the non-circular magnetic core includes an elliptical annular main body and a U-shaped extending portion.

[0015] According to the concept of the present invention, when the choke coil is installed on the circuit board, at least three or more capacitors are provided adjacent to one side of the choke coil.

[0016] According to the concept of the present invention, when the choke coil is installed on the circuit board, at least three or more capacitors are provided adjacent to both opposite sides of the choke coil.

[0017] According to the concept of the present invention, at least three or more winding sets are installed in series, in parallel, or in series and parallel.

[0018] According to the concept of the present invention, the noise filter further includes an additional circuit board, and the additional circuit board has at least one capacitor for being connected corresponding to the second outgoing ends of at least three or more winding sets.

[0019] According to the concept of the present invention, the present invention provides a noise filter including a circuit board, an additional circuit board, and a choke coil. At least three or more capacitors are provided on the circuit board. At least one capacitor is provided on the additional circuit board. The choke coil is interposed between the circuit board and the additional circuit board, and includes a non-circular magnetic core and at least three or more winding sets wound around the non-circular magnetic core. At least three or more capacitors on the circuit board and at least one capacitor on the additional circuit board are both provided adjacent to the choke coil. The first outgoing ends of at least three or more winding sets are connected corresponding to at least three or more capacitors on the circuit board, and the second outgoing ends of at least three or more winding sets are connected corresponding to at least one capacitor on the additional circuit board.

[0020] According to the concept of the present invention, the bottom side of the choke coil is installed corresponding to the circuit board, and the top side of the choke coil is installed corresponding to the additional circuit board.

Brief Description of the Drawings

[0021]

Figure 1A

Figure 1B

Figure 1C

Figure 2

Figure 3

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 6

Figure 7A

Figure 7B

Figure 8

Modes for Carrying Out the Invention

[0022] Some typical embodiments showing the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can be modified in various forms, all without departing from the scope of the present invention, and the description and drawings are essentially for explanatory purposes and are not intended to limit the present invention.

[0023] Refer to FIGS. 2 and 3. FIG. 2 is a schematic diagram of a noise filter according to a preferred embodiment of the present invention. FIG. 3 is a schematic diagram of the choke coil shown in FIG. 2. In this embodiment, the noise filter 4 is applied to a three-phase system and includes a circuit board 3 and a choke coil 2. The choke coil 2 may be, but is not limited to, a noise filter or an inductor for suppressing electromagnetic noise in a circuit board assembly of an electronic device such as a switching power supply. A plurality of electronic components 30 including at least three or more capacitors 31 are provided on the circuit board 3. The choke coil 2 is installed on the circuit board 3 and includes a non-circular magnetic core 21 and at least three or more winding sets 22. The non-circular magnetic core 21 has a hollow portion 210 inside, and at least three or more winding sets 22 are wound corresponding to the non-circular magnetic core 21. The non-circular magnetic core 21 can have any shape other than circular. In this embodiment, the form of the non-circular magnetic core 21 is an elliptical ring-shaped magnetic core close to a square, but it is not limited to this. When this choke coil 2 is installed on the circuit board 3, at least three or more capacitors 31 are provided adjacent to one side of the choke coil 2, and the first lead-out end 22a of the at least three or more winding sets 22 is connected corresponding to the at least three or more capacitors 31.

[0024] As shown in FIG. 3, in this embodiment, the form of the non-circular magnetic core 21 of the choke coil 2 is an elliptical ring-shaped magnetic core, which includes a first magnetic body part 211, a second magnetic body part 212, a third magnetic body part 213, and a fourth magnetic body part 214. The first magnetic body part 211 and the second magnetic body part 212 are installed in parallel corresponding to each other, and the third magnetic body part 213 and the fourth magnetic body part 214 are also installed in parallel corresponding to each other. The third magnetic body part 213 and the fourth magnetic body part 214 are respectively installed between the first magnetic body part 211 and the second magnetic body part 212, and the lengths of the first magnetic body part 211 and the second magnetic body part 212 are greater than the lengths of the third magnetic body part 213 and the fourth magnetic body part 214. In this embodiment, the connection locations between the first magnetic body part 211, the second magnetic body part 212, the third magnetic body part 213, and the fourth magnetic body part 214 are fillet structures, but it is not limited thereto. Taking this embodiment as an example, the winding set 22 may be a copper foil coil, but it is not limited thereto. The number thereof is six, but the form of the non-circular magnetic core 21 and the number and material of the winding set 22 are not limited thereto and can be arbitrarily changed according to the actual implementation situation. In this embodiment, the six winding sets 22 are wound around the non-circular magnetic core 21 at intervals from each other, and a part of each winding set 22 passes through the hollow part 210 of the non-circular magnetic core 21. In some embodiments, two of the six winding sets 22 are wound around the first magnetic body part 211, three are wound around the second magnetic body part 212, and one is wound around the third magnetic body part 213. Therefore, their lead-out positions are arranged substantially regularly, that is, arranged in the horizontal direction or the vertical direction. However, the winding positions of the winding set 22 of the present invention are not limited thereto and can be arbitrarily changed according to the actual implementation situation.

[0025] Refer to FIGS. 1C and 2 simultaneously. In this embodiment, since the non-circular magnetic core 21 is an elliptical annular magnetic core, the hollow portion 210 inside it has a relatively large space, so that the winding distance between the winding sets 22 can be adjusted according to the actual wiring requirements. Compared with the prior art shown in FIG. 1C, since the winding distance of the winding set 22 in this embodiment is large, the problem of wiring difficulty in the prior art can be solved. Also, in this embodiment, six winding sets 22 are wound around the elliptical annular magnetic core. When the six winding sets 22 are installed in series in pairs, the number of turns is significantly more than the number of turns of each conventional coil 12. In other words, the winding set 22 in this embodiment can increase the inductance by connecting a plurality of winding sets 22 in series. In other embodiments, when the inductance is the same and trying to reduce the loss by dispersing the current when the current is too large, the six winding sets 22 can be installed in parallel to shunt the current and reduce the loss. Also, when comparing the noise filter 4 in this embodiment with the prior art, as can be seen from FIG. 2, since the non-circular magnetic core 21 in this embodiment is an elliptical annular magnetic core, when six winding sets 22 are wound around the elliptical annular magnetic core, the lead-out positions are arranged almost regularly, that is, arranged in the horizontal or vertical direction. Therefore, when installed on the circuit board 3, there is sufficient space around the lead-out positions to install electronic components. Thus, 14 electronic components can be installed on the circuit board 3 of the present invention, and there is little empty space on the circuit board 3. In contrast, as shown in FIG. 1C, the conventional choke coil 1 has a circular magnetic core 11, and three sets of coils 12 are wound around the circular magnetic core 11 diagonally to each other. Therefore, due to the shape of the circular magnetic core 11 and its diagonal lead-out position, it is difficult to arrange electronic components around it. Therefore, only 11 electronic components can be installed on the conventional circuit board 3, there is a lot of unusable space on the circuit board 3, and the space utilization rate is clearly poor.As described above, in this embodiment, an elliptical annular magnetic core is adopted as the non-circular magnetic core 21, and further, at least three or more winding sets 22 are wound around the non-circular magnetic core 21 substantially horizontally or vertically, thereby effectively improving the space utilization rate of the circuit board 3, increasing the number of electronic components on the circuit board 3, and facilitating the layout and design of the circuit board 3. Of course, the number of electronic components on the circuit board 3 of this embodiment is not limited to the above number and can be arbitrarily changed according to the actual implementation situation.

[0026] Refer to FIGS. 4A and 4B. FIG. 4A is a schematic diagram of the choke coil of the noise filter according to the second preferred embodiment of the present invention. FIG. 4B is a schematic diagram of the choke coil of the noise filter according to the third preferred embodiment of the present invention. As can be seen from FIGS. 4A and 4B, the form of the non-circular magnetic core 21 of the choke coil 2 in this embodiment is not limited to an elliptical annular magnetic core and may have an irregular shape. In some embodiments, the non-circular magnetic core 21 of the choke coil 2 is a waveform annular magnetic core, which also has a hollow portion inside. As shown in FIG. 4A, the at least three or more winding sets 22 are wound around the non-circular magnetic core 21, which is a waveform annular magnetic core, while being spaced apart from each other, and a part of each winding set 22 passes through the hollow portion 210 of the non-circular magnetic core 21. In other embodiments, the non-circular magnetic core 21 of the choke coil 2 is a star-shaped annular magnetic core as shown in FIG. 4B, and the at least three or more winding sets 22 are wound around the non-circular magnetic core 21, which is a star-shaped annular magnetic core, while being spaced apart from each other, and a part of each winding set 22 passes through the hollow portion 210 of the non-circular magnetic core 21. Thus, the non-circular magnetic core 21 of the choke coil 2 of the present invention can have any shape other than circular, can have various forms, can be arbitrarily changed according to the actual implementation situation, and is not limited to the above-described aspects.

[0027] Refer to FIGS. 5A and 5B. FIG. 5A is a schematic side view showing the structure of the noise filter according to the fourth preferred embodiment of the present invention. FIG. 5B is a schematic plan view of the schematic structure of FIG. 5A. In this embodiment, the noise filter 4 also includes a circuit board 3 and a choke coil 2. The choke coil 2 is installed on the circuit board 3 and includes a non-circular magnetic core 21 and at least three or more winding sets 22. The at least three or more winding sets 22 are wound around the non-circular magnetic core 21 and are spaced apart from each other, and a part of each winding set 22 passes through the hollow portion 210 of the non-circular magnetic core 21. In this embodiment, since the number of turns of any two winding sets 22 is the same, as in the previous embodiment, they can be arranged in series or in parallel according to different situations to increase the inductance or shunt the current. Of course, in other embodiments, they can also be arranged in series and in parallel, and can be arbitrarily changed according to the actual implementation situation, and are not limited thereto. The circuit board 3 has at least three or more capacitors 31. Taking this embodiment as an example, the number of the at least three or more capacitors 31 is three. The three capacitors 31 are provided adjacent to one side of the choke coil 2. The first lead-out end 22a of the at least three or more winding sets 22 is connected corresponding to the three capacitors 31. The second lead-out end 22b of the at least three or more winding sets 22 can be connected to a remote circuit board (not shown) via wiring, so as to be connected corresponding to a capacitor (not shown) on the remote circuit board. In other words, taking this embodiment as an example, mainly, one side of the choke coil 2 is directly electrically connected to at least three capacitors 31 on the circuit board 3, and the other side is electrically connected to a remote circuit board (not shown) via wiring. However, in other embodiments, the circuit board 3 may be provided with 4, 5 or 6 capacitors 31, and may be installed corresponding to both opposite sides or any two sides of the winding set 22. The number and installation position of the capacitors 31 are mainly adjusted according to the form of the non-circular magnetic core 21 of the choke coil 2 and the lead-out position of the winding set 22, and are not limited thereto.Also, in some embodiments, the capacitor 31 can include a Y capacitor 31a and an X capacitor 31b. At this time, the first lead-out ends 22a of the at least three or more winding sets 22 are connected corresponding to the Y capacitor 31a and the X capacitor 31b simultaneously, but it is not limited thereto. In other embodiments, the choke coil 2 may be a differential mode inductance or a common mode inductance, and can be arbitrarily combined with a desired Y capacitor 31a and X capacitor 31b, and the number and installation method thereof are not limited thereto.

[0028] Refer to FIG. 6. FIG. 6 is a schematic plan view showing the structure of the noise filter according to the fifth preferred embodiment of the present invention. In this embodiment, the structure and arrangement method of the circuit board 3 and the choke coil 2 of the noise filter 4 are substantially the same as those of the above embodiment. However, in this embodiment, the form of the non-circular magnetic core 21 of the choke coil 2 is a combination of an elliptical annular magnetic core and a U-shaped magnetic core. In other words, the non-circular magnetic core 21 has an elliptical annular main body 215, and a part of the elliptical annular main body 215 protrudes outward to form a U-shaped extending portion 216. That is, both ends of the elliptical annular main body 215 are connected corresponding to both ends of the U-shaped extending portion 216. In this embodiment, at least three or more winding sets 22 are wound around the elliptical annular main body 215 at intervals from each other, and are not wound around the U-shaped extending portion 216. In other embodiments, the winding set 22 may be wound around the U-shaped extending portion 216 so as to match the wiring arrangement of the circuit board 3 and the position of the capacitor 31 thereon. Therefore, the form of the non-circular magnetic core 21 and the winding position of the at least three or more winding sets 22 can be arbitrarily changed according to the arrangement of the circuit board 3.

[0029] Refer to FIGS. 7A and 7B. FIG. 7A is a schematic side view showing the structure of the noise filter according to the sixth preferred embodiment of the present invention. FIG. 7B is a schematic plan view of the structure of FIG. 7A. As shown in FIGS. 7A and 7B, the noise filter 5 of the present embodiment includes not only the circuit board 3 and the choke coil 2, but also an additional circuit board 6. As can be seen from FIG. 7A, the choke coil 2 of the present embodiment is interposed between the circuit board 3 and the additional circuit board 6 to constitute a sandwich-type noise filter 5. In the present embodiment, the top side of the choke coil 2 is connected and installed corresponding to the additional circuit board 6, and the bottom side is installed corresponding to the circuit board 3, whereby the choke coil 2 is interposed between the circuit board 3 and the additional circuit board 6. As shown in FIG. 7B, the choke coil 2 also includes a non-circular magnetic core 21 and at least three or more winding sets 22. In the present embodiment, the number of the at least three or more winding sets 22 is six. That is, the six winding sets 22 of the present embodiment are wound around the non-circular magnetic core 21 and installed at intervals from each other, and a part of each winding set 22 passes through the hollow portion 210 of the non-circular magnetic core 21. Similar to the foregoing embodiment, the circuit board 3 has at least three or more capacitors 31. Taking the present embodiment as an example, the circuit board 3 has three capacitors, and the three capacitors 31 are provided adjacent to one side of the choke coil 2 and connected corresponding to the first outgoing ends 22a of the six winding sets 22. Similarly, at least three or more capacitors 61 are also provided on the additional circuit board 6. In the present embodiment, the number of the at least three or more capacitors 61 is three. As can be seen from FIG. 7A, the three capacitors 61 are installed corresponding to both opposite sides of the choke coil 2. That is, two capacitors 61 are installed on one side of the choke coil 2, and the other one capacitor 61 is installed on the other side of the choke coil 2, whereby the choke coil 2 is interposed between the three capacitors 61. The three capacitors 61 are connected corresponding to the second outgoing ends 22b of the six winding sets 22. In the present embodiment, since the capacitors 31 on the circuit board 3 and the capacitors 61 on the additional circuit board 6 are both provided adjacent to the choke coil 2, electromagnetic interference can be effectively suppressed.In some embodiments, the capacitors 31 and 61 can be provided adjacent to the choke coil 2 in a locking manner, but are not limited thereto. In addition, according to the sandwich arrangement method of this embodiment, the component installation positions and numbers of the circuit board 3 and the additional circuit board 6 can be adjusted more flexibly. For example, when the space of the circuit board 3 is not sufficient to arrange six capacitors 31, for example, when only three or four capacitors can be arranged, by installing the additional circuit board 6, the three or two capacitors that cannot be installed can be transferred to the additional circuit board 6, and the branched capacitors 61 can be adjusted or increased. In this way, by the installation method of the three-dimensional sandwich, the horizontal lead-out direction of the winding set 22 can be changed to the vertical up-and-down lead-out direction, and further, the volume of the entire noise filter 5 can be reduced, and the space utilization rate of the circuit board 3 and the additional circuit board 6 can be improved.

[0030] Refer to FIG. 8. FIG. 8 is a schematic perspective view showing the structure of the noise filter according to the seventh preferred embodiment of the present invention. In this embodiment, the structures of the circuit board 3 and the choke coil 2 of the noise filter 7 are substantially the same as those of the above-described embodiment. That is, the circuit board 3 includes at least three or more capacitors 31, and the choke coil 2 is installed on the circuit board 3 and includes a non-circular magnetic core 21 and at least three or more winding sets 22. The at least three or more winding sets 22 are wound around the non-circular magnetic core 21 and are spaced apart from each other, and a part of each winding set 22 passes through the hollow portion 210 of the non-circular magnetic core 21. However, in this embodiment, the number of at least three or more capacitors 31 on the circuit board 3 is three. One of them is installed on one side of the choke coil 2, and the other two capacitors 31 are installed corresponding to the other side of the choke coil 2. In other words, the three capacitors 31 are provided adjacent to both opposite sides of the choke coil 2, and the at least three or more winding sets 22 are sandwiched therebetween and are connected corresponding to the first lead-out end 22a (not shown) of the at least three or more winding sets 22. In this way, the number and installation position of the capacitors 31 on the circuit board 3 can be arbitrarily changed according to the size of the circuit board 3 and the actual situation, and are not limited thereto. However, in order to achieve the effect of suppressing electromagnetic interference, it is necessary to install at least three capacitors 31 adjacent to the choke coil 2.

[0031] As described above, the present invention includes a circuit board and a choke coil. The choke coil includes a non-circular magnetic core and at least three or more winding sets. The at least three or more winding sets are wound around the non-circular magnetic core and are connected to and adjacent to a capacitor on the circuit board, providing a noise filter. Since the inner diameter of this non-circular magnetic core is large, the winding positions of at least three or more winding sets can be separated by a certain distance, solving the wiring problem of the circuit board in the prior art. Also, by installing at least three or more winding sets in series, the inductance can be significantly increased, or by installing at least three or more winding sets in parallel, the current can be shunted to reduce losses. Thus, with the form of the non-circular magnetic core of the choke coil of the present invention, the winding positions of at least three or more winding sets, and the series and parallel connection methods, the number and position of capacitors on the circuit board can be flexibly adjusted, effectively increasing the space utilization rate of the circuit board, suppressing electromagnetic interference, reducing the volume of the entire device, increasing the inductance, or shunting the current to reduce losses, achieving the desired effects.

[0032] Those skilled in the art can make various modifications to the present invention, but they will not depart from the scope defined by the claims.

Explanation of Reference Numerals

[0033] 1: Conventional choke coil 11: Circular magnetic core 12, 121, 122, 123: Coils 121a, 122a: Pins 2: Choke coil 21: Non-circular magnetic core 210: Hollow part 211: First magnetic body part 212: Second magnetic body part 213: Third magnetic body part 214: Fourth magnetic body part 215: Elliptical ring-shaped body 216: U-shaped extending part 22: Winding set 22a: First lead end 22b: Second output terminal 3: Circuit board 30: Electronic component 31, 61: Capacitor 31a: Y capacitor 31b: X capacitor 4, 5, 7: Noise filter 6: Additional circuit board

Claims

1. A noise filter including a circuit board, an additional circuit board, and a choke coil, At least three capacitors are provided on the circuit board, At least one capacitor is provided on the additional circuit board; the choke coil is interposed between the circuit board and the additional circuit board, and includes a non-circular magnetic core and at least three or more winding sets, the winding sets being wound around the non-circular magnetic core; the at least three or more capacitors on the circuit board and the at least one capacitor on the additional circuit board are all provided adjacent to the choke coil, first output ends of the at least three or more winding sets are connected to correspond to the at least three or more capacitors on the circuit board, and second output ends of the at least three or more winding sets are connected to correspond to the at least one capacitor on the additional circuit board.

2. 2. The noise filter according to claim 1, wherein a bottom side of the choke coil is disposed corresponding to the circuit board, and a top side of the choke coil is disposed corresponding to the additional circuit board.

3. the non-circular magnetic core includes a first magnetic body portion, a second magnetic body portion, a third magnetic body portion, and a fourth magnetic body portion, the first magnetic body portion and the second magnetic body portion are arranged in parallel to correspond to each other, the third magnetic body portion and the fourth magnetic body portion are arranged in parallel to correspond to each other, and the third magnetic body portion and the fourth magnetic body portion are respectively arranged between the first magnetic body portion and the second magnetic body portion, 2. The noise filter according to claim 1, wherein at least one winding set is wound around each of the first magnetic body portion, the second magnetic body portion, and the third magnetic body portion.

4. 2. The noise filter according to claim 1, wherein the non-circular magnetic core has a hollow portion, and when the at least three or more winding sets are wound around the non-circular magnetic core, a portion of the winding set passes through the hollow portion of the non-circular magnetic core.

5. 2. The noise filter according to claim 1, wherein the non-circular magnetic core is an elliptical ring-shaped magnetic core.

6. 2. The noise filter according to claim 1, wherein the at least three or more winding sets are arranged in series, in parallel, or in series and in parallel.

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