Filter device, wire and filtering method

Abstract

The embodiment of the invention provides a filtering device, a wire and a filtering method, and the filtering device is used for filtering an AC component with a frequency higher than a set frequency, and comprises a magnetic conductor. The magnetic conductor comprises a solid mixture composed of a first substance and a second substance, the conductivity of the first substance is smaller than that of the second substance, and the magnetic conductivity of the first substance is larger than a set value; the width of the cross section of the magnetic conductor in any direction starting from the central point of the cross section is greater than two times of the skin depth of the magnetic conductor to the alternating current component with the set frequency; and the resistance of the magnetic conductor to direct current is less than or equal to 50 ohms. The filtering device comprises the magnetic conductor, the manufacturing cost is low, the structure is simple, the application scene is wide, and the filtering effect on the alternating current component of the current higher than the cut-off frequency is equivalent to that of an existing inductance filtering device composed of a coil and a magnetic core.

Description

Technical Field

[0001] This application relates to the field of circuit technology, and more particularly to a filtering device, wire, and filtering method. Background Technology

[0002] In DC power supply lines, it is desirable to filter out the high-frequency components of the current as much as possible, retaining only the DC component. Current solutions involve connecting an inductor and a ferrite bead in series with the power cable, and a capacitor in parallel. The inductor and ferrite bead are mainly composed of wires and a magnetic core, which are two completely separate parts made of different materials. This results in complex manufacturing processes, high production costs, and the fact that both the AC and DC components of the current generate magnetic flux in the magnetic core, affecting the filtering effect.

[0003] Almost all elemental materials are unsuitable for using the skin effect principle to make filters. The resistivity of most metals is too low to achieve a filtering effect for high-frequency signals. For example, to filter a 1mm diameter cylindrical pure silver device for a 100MHz AC component, the length would need to reach 62m to achieve an impedance of 50 ohms for the AC component, which is completely impractical. Furthermore, devices of a specific size produced from the same element cannot have their impedance to the DC and AC components of a current signal adjusted simply by changing the material ratio. Summary of the Invention

[0004] In view of this, embodiments of this application provide a filtering device, wire, and filtering method. The magnetic conductor of the filtering device in this application includes a magnetic conductor with high permeability and high conductivity. It utilizes the skin effect for AC filtering, eliminating the need for strictly separated magnetic cores and coils wound around the magnetic core. This results in low manufacturing cost, simple structure, and wide applicability. The filtering effect on AC components above the cutoff frequency is comparable to that of existing inductor and bead filtering devices composed of coils and magnetic cores.

[0005] In a first aspect, embodiments of this application provide a filtering device for filtering AC components with frequencies higher than a set frequency, comprising: a magnetic conductor; the magnetic conductor comprising a solid mixture of a first material and a second material, wherein the conductivity of the first material is less than the conductivity of the second material, and the magnetic permeability of the first material is greater than a first set value; the width of the cross-section of the magnetic conductor in any direction emanating from the center point of the cross-section is greater than twice the skin depth of the magnetic conductor to the AC component of the set frequency, and the resistance of the magnetic conductor to the DC component is less than or equal to 50 ohms.

[0006] As described above, the magnetic conductor of the filter device of this application utilizes the skin effect for AC filtering, eliminating the need for strictly separated magnetic cores and coils wound around the magnetic cores. This results in low manufacturing costs, simple structure, and wide applicability. The filtering effect on AC components above the cutoff frequency is comparable to that of existing inductor and bead filter devices composed of coils and magnetic cores.

[0007] In one possible implementation of the first aspect, the length of the magnetic conductor is obtained based on the skin depth, the cross-sectional perimeter, the conductivity of the magnetic conductor, and the impedance requirement for AC signals above the set frequency.

[0008] As described above, the length of the magnetic conductor is obtained based on the skin depth, cross-sectional perimeter, conductivity, and impedance requirements for AC signals above a set frequency, thereby controlling the size of the filter device.

[0009] In one possible implementation of the first aspect, the first and second substances are uniformly distributed in the magnetic conductor, and its permeability is equal to the weighted average of the permeability of the first and second substances in the mixture based on the component ratio, and its conductivity is equal to the weighted average of the conductivity of the first and second substances based on the component ratio.

[0010] Based on the above, by selecting appropriate first and second materials and controlling the ratio of the first and second materials in the magnetic conductor, the magnetic conductor can have relatively strong conductivity and high permeability. The DC component of the current will be evenly distributed inside the device, while the AC component will exhibit a skin effect, with most of the AC component only distributed near the outer surface of the magnetic conductor. In this way, the magnetic conductor is a low-impedance device for the DC component, with a small proportion of DC component energy loss; and a high-impedance device for the AC component, with a large AC component energy loss.

[0011] In one possible implementation of the first aspect, the second substance comprises one of the following: graphite, a metal containing high electrical conductivity; and / or the first substance comprises ferrite.

[0012] Therefore, by selecting appropriate first and second materials, the magnetic conductor filters out AC components with frequencies higher than the set frequency, allowing DC components to pass through.

[0013] Secondly, embodiments of this application provide a filtering device for filtering AC components with frequencies higher than a set frequency, comprising: a magnetic conductor having a multilayer structure, wherein the conductivity of each layer gradually increases from the outside in; each layer of the magnetic conductor, except for the innermost layer, comprises a solid mixture composed of a first substance and a second substance, wherein the conductivity of the first substance is less than the conductivity of the second substance, and the permeability of the first substance is greater than a first set value; the innermost layer is a solid mixture composed of the second substance or a solid mixture composed of the first substance and the second substance, wherein the proportion of the second substance is greater than that of the other layers; the width of the outermost layer of the magnetic conductor in cross-section is greater than twice the skin depth of the layer to the AC component of the set frequency, and the resistance of the innermost layer of the magnetic conductor to the DC component is less than or equal to 50 ohms.

[0014] As shown above, a filter device is constructed using multiple layers of magnetic conductors. From the outside in, the permeability of each layer gradually decreases, while the conductivity gradually increases, with the outermost layer having the highest permeability. Due to the skin effect, the AC component is distributed in the outermost layer of the filter device, achieving better filtering of the AC component. The innermost layer provides better conduction for the DC component.

[0015] In one possible implementation of the second aspect, a first substance and a second substance are uniformly distributed in each layer of the magnetic conductor; from the outside in, the proportion of the first substance decreases and the proportion of the second substance increases in each layer of the magnetic conductor.

[0016] Based on the above, by selecting appropriate first and second materials and controlling the ratio of first and second materials in each layer of the magnetic conductor, the inner layer of the magnetic conductor has relatively strong conductivity, and the outermost layer has high permeability, resulting in better filtering effect.

[0017] In one possible implementation of the second aspect, the permeability of each layer of the magnetic conductor is equal to the weighted average of the permeability of the first and second materials of that layer based on the composition ratio, and the conductivity of each layer of the magnetic conductor is equal to the weighted average of the conductivity of the first and second materials of that layer based on the composition ratio.

[0018] By controlling the ratio of the first and second materials in each layer of the magnetic conductor, the inner layer of the magnetic conductor has a relatively strong conductivity, and the outermost layer has a high magnetic permeability, resulting in a better filtering effect.

[0019] In one possible implementation of the second aspect, embodiments of this application provide that the equivalent permeability of each layer in the magnetic conductor, excluding the outermost layer, is estimated based on the permeability and cross-sectional area of ​​that layer and the layers extending outward from it, wherein the equivalent permeability of the outermost layer is equal to the permeability of that layer.

[0020] Based on the above, the equivalent permeability of each layer is estimated to control the equivalent permeability of each layer to gradually increase from the outside to the inside, thereby further improving the filtering effect.

[0021] In one possible implementation of the second aspect, the length of the magnetic conductor is obtained based on the skin depth, the cross-sectional perimeter, the conductivity of the outermost layer of the magnetic conductor, and the impedance requirement for AC signals above the set frequency.

[0022] As described above, the length of the magnetic conductor is obtained based on the skin depth of the outermost layer, the cross-sectional perimeter, the conductivity, and the impedance value requirement of the AC signal above the set frequency, thereby controlling the size of the filter device.

[0023] In one possible implementation of the second aspect, from the outside in, the impedance value of the AC signal gradually increases in each layer of the magnetic conductor, and the impedance value of each layer to the AC signal is obtained according to the equivalent permeability of that layer.

[0024] As shown above, the impedance value of each layer to the AC signal is obtained based on the equivalent permeability of that layer, so as to control the impedance value of the AC signal to gradually increase from the outside to the inside of the magnetic conductor.

[0025] In one possible implementation of the second aspect, the second substance comprises one of the following: graphite, a metal containing high electrical conductivity; and / or the first substance comprises ferrite.

[0026] Therefore, by selecting appropriate first and second materials, the magnetic conductor filters out AC components with frequencies higher than the set frequency, allowing DC components to pass through.

[0027] In one possible implementation of the second aspect, a layer is inserted between any two layers of the magnetic conductor. This layer is a solid object composed of a third material that is non-conductive and has a magnetic permeability greater than a second predetermined value.

[0028] As described above, by inserting a solid object composed of a non-conductive material with high magnetic permeability between any two layers of a magnetic conductor, the magnetic conductor can continue to filter AC components with frequencies higher than a set frequency, allowing DC components to pass through, while also reducing manufacturing costs.

[0029] Thirdly, embodiments of this application provide a wire that includes a magnetic conductor in any of the filtering devices described in the first or second aspect.

[0030] Fourthly, embodiments of this application provide a filtering method that uses any of the filtering devices described in the first or second aspect and the conductor described in the third aspect to filter AC components with frequencies higher than a set frequency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a filter device according to one embodiment of this application;

[0032] Figure 2 This is a schematic diagram of the two-layer structure of a filter device according to Embodiment 2 of this application;

[0033] Figure 3 This is a schematic diagram of the three-layer structure of a filter device according to a second embodiment of this application;

[0034] Figure 4 This is a schematic diagram of the irregular structure of the filter device according to Embodiment 2 of this application;

[0035] Figure 5 This is a schematic diagram of the structure of a third embodiment of a filtering device according to this application. Detailed Implementation

[0036] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0037] In the following description, the terms “first, second, third, etc.” or module A, module B, module C, etc. are used not only to distinguish similar objects or different embodiments, but also do not represent a specific ordering of objects. It is understood that a specific order or sequence may be interchanged where permitted so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0038] In the following description, the labels of the steps, such as S110, S120, etc., do not necessarily mean that the steps will be executed in this way. The order of the steps can be interchanged or executed simultaneously if permitted.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0040] This application provides a filtering device, a wire, and a filtering method. The filtering device is used to filter AC components with frequencies higher than a set frequency and includes a magnetic conductor. The magnetic conductor comprises a solid mixture of a first material and a second material, wherein the electrical conductivity of the first material is less than that of the second material, and the magnetic permeability of the first material is greater than a first set value. The width of the cross-section of the magnetic conductor in any direction from the center point of the cross-section is greater than twice the skin depth of the magnetic conductor to the AC component of the set frequency. The resistance of the magnetic conductor to DC is less than or equal to 50 ohms.

[0041] The filtering device in this application embodiment utilizes the skin effect for AC filtering, eliminating the need for strictly separate magnetic cores and coils wound around them. This results in low manufacturing costs, a simple structure, and wide applicability. Its filtering effect on AC components above the cutoff frequency is comparable to existing inductor and bead filters composed of coils and magnetic cores. It can be used not only for power line filtering but also for signal line filtering.

[0042] The embodiments of this application are described below with reference to the accompanying drawings. First, in conjunction with... Figure 1 An embodiment of a filtering device is introduced.

[0043] Figure 1 An embodiment of the filter device described in this application is illustrated. This filter device is used to filter currents with frequencies higher than a set frequency. The filter device is a section of magnetic conductor connected in series with wires at both ends in a circuit. The filter device of this application also includes terminals for connection to the circuit at both ends. The form of the terminals is not limited, and may include pads, etc.

[0044] For example, Figure 1 The medium magnetic conductor is a cylinder, but it can also be other shapes.

[0045] The magnetic conductor comprises a solid mixture of a first substance and a second substance, which do not react chemically. The magnetic conductor has high magnetic permeability and high electrical conductivity, with the first substance contributing to the high magnetic permeability and the second substance contributing to the high electrical conductivity.

[0046] In this process, the electrical conductivity of the first material is less than that of the second material, and the magnetic permeability of the first material is greater than a first predetermined value. For example, the first material may include ferrite, etc.; the second material may be a material with high electrical conductivity, such as graphite or a metal.

[0047] By selecting appropriate first and second materials and controlling their ratio in the magnetic conductor, the magnetic conductor can achieve strong conductivity and high permeability. The DC component of the current will be evenly distributed inside the device, while the AC component will exhibit a skin effect, distributing only near the outer surface of the magnetic conductor. Thus, the magnetic conductor is a low-impedance device for the DC component, with a relatively small proportion of DC component energy loss; and a high-impedance device for the AC component, with a relatively large AC component energy loss.

[0048] In this process, after selecting the first and second materials, the ratio of the first and second materials in the magnetic conductor and the geometric dimensions of the magnetic conductor are controlled so that the resistance of the magnetic conductor to DC is less than or equal to the set ohm value, and the width of the cross-section of the magnetic conductor in any direction through the center point of the cross-section is at least twice the skin depth of the magnetic conductor to the AC component of the set frequency. Thus, the impedance value of the magnetic conductor to the AC component above the set frequency is greater than the impedance value of the magnetic conductor to DC, and the minimum value is generally not lower than the set ohm value.

[0049] Using a cylindrical magnetic conductor diagram as an example, this section explains how to obtain filtering devices.

[0050] (1) First, based on the permeability and conductivity of the magnetic conductor, calculate the skin depth of the AC component at a given frequency.

[0051] (2) Design the radius R of the magnetic conductor cross section to be greater than twice the skin depth obtained in step (1).

[0052] (3) Design the length of the magnetic conductor so that the impedance value of the magnetic conductor within the skin depth of the AC component of the set frequency is greater than or equal to the set ohm value, which serves as the AC resistance.

[0053] (4) Calculate the resistance corresponding to the conductivity of the magnetic conductor, and use it as the DC resistance.

[0054] In some embodiments of this example, the magnetic conductor is a solid mixture composed of a first substance and a second substance and uniformly distributed therein, the magnetic permeability of which is equal to the weighted average of the magnetic permeability of the first substance and the second substance in the mixture based on the component ratio, and the electrical conductivity of which is equal to the weighted average of the electrical conductivity of the first substance and the second substance based on the component ratio.

[0055] For example, let the first substance be substance A, the second substance be substance B, and the conductivity of substance A be γ. a The permeability is μ a The conductivity of substance B is γ b The permeability is μ b If material A accounts for x% of the magnetic conductor, then the permeability μ and conductivity γ of the magnetic conductor can be obtained through (1).

[0056]

[0057] The skin depth of the magnetic conductor is obtained by (2).

[0058]

[0059] Where Δ is the skin depth and ω is the angular frequency of the AC component.

[0060] The following example uses a magnetic conductor composed of graphite powder and ferrite powder, which is a cylinder with a diameter of 1 mm and a length of 2 mm. The impedance values ​​of the magnetic conductor to the 100 MHz AC component under different proportions of graphite and ferrite are shown in the table below.

[0061]

[0062] As shown in the table above, by controlling the component ratio of the mixture, the impedance value of the magnetic conductor to the set AC component can meet the requirements.

[0063] In some embodiments of this example, the length of the magnetic conductor is obtained based on its skin depth, cross-sectional perimeter, conductivity, and impedance requirements for AC signals above a set frequency, thereby controlling the size of the filter device.

[0064] In summary, the magnetic conductor of the filter device described in Embodiment 1 includes a section of magnetic conductor with high permeability and high conductivity. It utilizes the skin effect to filter the AC component of the current, eliminating the need for a combination of magnetic core and wire. This results in low manufacturing cost, simple structure, and wide applicability. Its filtering effect on AC components above the cutoff frequency is comparable to that of existing inductor and bead filter devices composed of coils and magnetic cores. While the DC component of the current generates magnetic flux within the device, the AC component generates very little magnetic flux. The device also avoids the parasitic capacitance effect caused by coils and can operate at relatively high frequencies.

[0065] Compared to inductors and ferrite beads, inductors have better filtering performance in the low-frequency range but poorer filtering performance in the high-frequency range. Ferrite beads, on the other hand, perform well in high-frequency environments. However, this application uses a method of mixing conductive materials and high-permeability materials, which eliminates the coil in the production of ferrite beads / inductors, reduces the materials and production processes related to winding in the device production, and lowers costs. Moreover, since there is no internal conductor coil, there is no parasitic capacitance effect caused by the coil, and the filtering device of this embodiment can operate at higher frequencies.

[0066] The following is combined with Figures 2 to 4 A second embodiment of a filtering device is introduced.

[0067] The filter device of embodiment two is developed into a multi-layer structure based on the filter device of embodiment one, and has all the advantages of the filter device of embodiment one.

[0068] A second embodiment of a filter device includes a magnetic conductor with a multilayer structure. The conductivity of each layer gradually increases from the outside in. The main body of the filter device is a multilayer magnetic conductor, and its two ends also include terminals for connection to a circuit. Each terminal is connected to all layers, and the form of the terminals is not limited, including pads, etc.

[0069] In this structure, each layer of the magnetic conductor, except for the innermost layer, comprises a solid mixture of a first substance and a second substance. The electrical conductivity of the first substance is less than that of the second substance, and the magnetic permeability of the first substance is greater than a first set value. The first substance and the second substance do not react chemically. The innermost layer is either a solid mixture composed of the second substance or a solid mixture composed of the first substance and the second substance, with the proportion of the second substance being greater than that of the other layers.

[0070] The first material contributes to high magnetic permeability, while the second material contributes to high electrical conductivity. The outermost layer of a magnetic conductor has the highest magnetic permeability, and the innermost layer has the highest electrical conductivity.

[0071] For example, the first substance includes ferrites, etc.; the second substance is a highly conductive substance, such as graphite or metal.

[0072] In this process, the permeability of each layer of the magnetic conductor gradually decreases from the outside in. Due to the skin effect, the energy of the AC component is mainly concentrated near the surface of the outermost layer of the magnetic conductor. The width of the outermost layer of the magnetic conductor in cross-section is more than twice the skin depth of the layer for the AC component of the set frequency.

[0073] Among them, because the conductivity of the magnetic conductor gradually increases from the outside to the inside, the DC component is mainly concentrated in the innermost layer of the magnetic conductor, and the resistance of the innermost layer of the magnetic conductor to the DC component is less than or equal to 50 ohms.

[0074] The length of the magnetic conductor is determined based on the skin depth of its outermost layer to the AC component of a set frequency, its cross-sectional perimeter, its conductivity, and the target impedance value to the AC component of the set frequency, thereby controlling the length of the magnetic conductor. For example, the target impedance value is greater than the magnetic conductor's impedance to DC; when filtering power lines, the minimum target impedance value is generally not less than 5 ohms.

[0075] As shown above, through the multi-layer structure, the outermost layer has the highest permeability, and the innermost layer has the highest conductivity. When conducting DC components, there is no need to consider the permeability, and the filtering effect on AC components is better.

[0076] In some embodiments of this example, each layer of the magnetic conductor is a uniformly distributed solid mixture composed of a first material and a second material. Its permeability is equal to the weighted average of the permeabilities of the first and second materials within the mixture based on their component proportions, and its conductivity is equal to the weighted average of the conductivity of the first and second materials based on their component proportions. The permeability and conductivity of each layer of the magnetic conductor can be obtained using equation (1) from one embodiment of a filtering device.

[0077] In one embodiment of this invention, the first and second materials are uniformly distributed in each layer. By decreasing the proportion of the first material and increasing the proportion of the second material in each layer from the outside in, the conductivity of each layer gradually increases from the outside in. By selecting suitable first and second materials and controlling the ratio of the first and second materials in each layer of the magnetic conductor, the inner layer of the magnetic conductor has relatively strong conductivity, and the outermost layer has high magnetic permeability, resulting in better filtering effect.

[0078] In one embodiment of this invention, the equivalent permeability of each layer in the magnetic conductor, excluding the outermost layer, is obtained based on the permeability and cross-sectional area of ​​that layer and all layers extending outwards from it. The equivalent permeability of the outermost layer is equal to the permeability of that layer. It should be noted that the equivalent permeability here is an index within a multilayer structure, used to evaluate the filtering effect of each layer on AC signals in a multilayer structure, and is different from the permeability of each layer.

[0079] Figure 2The illustrated filter device, according to Embodiment 2, has a two-layer structure, comprising an outer layer C and an inner layer D. The cross-sectional area of ​​the outer layer C is M1, and the permeability of the outer layer material is μ. c The cross-sectional area of ​​the inner layer D is M2, and the magnetic permeability of the inner layer materials is μ. d The equivalent permeability μ of the inner layer D is estimated using equation (3). d1 .

[0080] μ d1 =μ d +μ c *(M1 / M2) (3)

[0081] Figure 3 An example of a filter device according to Embodiment 2 is a three-layer structure, comprising an outer layer C, a middle layer E, and an inner layer D. The cross-sectional area of ​​the outer layer C is M1, and the permeability of the outer layer material is μ. c The cross-sectional area of ​​the intermediate layer E is M2, and the magnetic permeability of the intermediate layer material is μ. e The cross-sectional area of ​​the inner layer D of the inner layer material is M3, and the magnetic permeability is μ. d The equivalent permeability μ of the intermediate layer E and the inner layer D is estimated using equation (4). e1 and μ d1 .

[0082]

[0083] In this context, the skin depth of each layer of the magnetic conductor can be estimated using Equation (2) in Example 1 of a filter device based on the equivalent permeability of each layer of the magnetic conductor, thereby estimating the impedance value of each layer to the AC signal. Note that the permeability in Equation (2) needs to be replaced with the equivalent permeability.

[0084] When controlling the equivalent permeability of each layer of a magnetic conductor to control the concentration of AC signals in the outermost layer, the equivalent permeability is first changed by controlling the cross-sectional area of ​​each layer of the magnetic conductor, as indicated by formula (3) or (4), so that the equivalent permeability of each layer reaches the target value from the outside to the inside and gradually increases, thereby gradually increasing the impedance to AC signals. If the target cannot be achieved, the composition ratio of the first and second substances in each layer of the magnetic conductor is changed by combining formula (1) to change the permeability of each layer, thereby changing the equivalent permeability of each layer.

[0085] When obtaining the impedance value of any layer to an AC signal based on the equivalent permeability of the controlled magnetic conductor, the outer layers are ignored, and the equivalent permeability of the layer is used as the permeability of the layer to estimate the impedance value of the layer to the AC signal.

[0086] The filtering device in this embodiment can be an irregular layered structure. Figure 4The example shown is an irregularly layered structure of a filter device according to Embodiment 2. The magnetic conductor of this structure also meets the above requirements, such as: from the outside to the inside, the permeability of each layer gradually decreases and the conductivity gradually increases, and the resistance of the innermost layer to the DC component is less than or equal to 50 ohms.

[0087] It is important to note that: Figure 2 and Figure 4 The two-layer structure of a medium magnetic conductor Figure 3 The three-layer structure of the magnetic conductor is just an example; in real-world scenarios, magnetic conductors can be multi-layered structures with other numbers of layers.

[0088] In summary, the second embodiment of the filter device is constructed by multiple layers of magnetic conductors. The outermost layer has the highest permeability. Due to the skin effect, the AC component is distributed in the outermost layer of the filter device, thus achieving better filtering of the AC component. The innermost layer conducts DC component better.

[0089] Similarly, compared with inductors and ferrite beads, this embodiment uses a method of mixing conductive materials and high permeability materials, which eliminates the coil in the production of ferrite beads / inductors, reduces the materials and production processes related to winding in the device production, and lowers the cost. Moreover, since there is no internal conductor coil, there is no parasitic capacitance effect caused by the coil, and the filter device in this embodiment can operate at a higher frequency.

[0090] The following is combined with Figure 5 This paper introduces a third embodiment of a filtering device.

[0091] In a second embodiment of a filter device, a layer is inserted into any two layers of the magnetic conductor, possessing all the advantages of the filter device of the second embodiment. The inserted layer is a solid object composed of a third material, which is non-conductive and has a magnetic permeability greater than a second predetermined value. The main body of the filter device is a multilayer magnetic conductor, with terminals at both ends for connection to a circuit. Each terminal is connected to all layers, and the form of the terminals is not limited, including pads, etc.

[0092] Figure 5 The diagram illustrates a structure for a third embodiment of a filtering device, using a three-layer structure as an example. In practice, this could involve multiple layers: layer X is the innermost layer, layer Y is the middle layer, and layer Z is the outermost layer. Originally, there were only two layers, with layer Y serving as an insertion layer. This three-layer structure is just one example; it can include any number of layers, either three or more.

[0093] Layer Z comprises a solid mixture of a first substance and a second substance, wherein the electrical conductivity of the first substance is less than that of the second substance, the magnetic permeability of the first substance is greater than a first set value, and the first substance and the second substance do not react chemically. Layer X is a solid substance composed of the second substance or a solid mixture composed of the first substance and the second substance, wherein the proportion of the second substance is greater than that of the other layers.

[0094] Layer Y is a solid object composed of a third substance. This third substance is non-conductive and its magnetic permeability is greater than the second set value.

[0095] The first material contributes to high magnetic permeability, while the second material contributes to high electrical conductivity. The innermost layer of the magnetic conductor has the highest electrical conductivity.

[0096] For example, the first substance includes ferrites, etc.; the second substance is a highly conductive substance, such as graphite or metal.

[0097] Due to the skin effect, the energy of the AC component is mainly concentrated near the surface of the Z layer of the magnetic conductor. The width of the Z layer in cross-section is more than twice the skin depth of the layer for the AC component of the set frequency.

[0098] The DC component is mainly concentrated in the X layer of the magnetic conductor, and the resistance of the X layer to the DC component is less than or equal to 50 ohms.

[0099] The length of the magnetic conductor is determined based on the skin depth of its outermost layer to the AC component of a set frequency, its cross-sectional perimeter, its conductivity, and the target impedance value to the AC component of the set frequency, thereby controlling the length of the magnetic conductor. For example, the target impedance value is greater than the magnetic conductor's impedance to DC, and the minimum value is generally not less than 5 ohms.

[0100] As shown above, through the multi-layer structure, the outermost layer has the highest permeability, and the innermost layer has the highest conductivity. When the DC component is turned on, the permeability does not need to be considered, and the filtering effect on the AC component is better.

[0101] Each possible implementation of a filter device in Embodiment 2 can also be a possible implementation of a filter device in Embodiment 3, which will not be elaborated here.

[0102] In summary, a third embodiment of a filter device inserts a layer of a solid material composed of a non-conductive substance with a permeability greater than a second predetermined value into any two layers of the magnetic conductor described in the second embodiment of a filter device. This maintains the advantages of the second embodiment of the filter device while further reducing manufacturing costs. Similarly, compared to inductors and ferrite beads, the filter device of this embodiment can still operate at higher frequencies.

[0103] This application also provides a wire, which includes a magnetic conductor from the filter device described in one, two, or three of the filter device embodiments. The wire also includes endpoints for connection to a circuit at both ends; the form of the endpoints is not limited, and may include pads, etc.

[0104] The conductor has high magnetic permeability and high electrical conductivity. It uses the skin effect to filter AC components above a set frequency and uses high electrical conductivity to allow signals below a set frequency to pass through. It has all the advantages of the filter device described in Embodiment 1, Embodiment 2, or Embodiment 3 of the corresponding filter device.

[0105] This application also provides a filtering method, which uses a filter device described in Embodiment 1, Embodiment 2, or Embodiment 3, or a conductor described in a conductor embodiment, to filter AC components with frequencies higher than a set frequency.

[0106] The filter device is connected in series in the circuit. Its magnetic conductor has high permeability and high conductivity. It uses the skin effect to filter AC components with frequencies higher than the set frequency and uses the high conductivity to allow signals with frequencies lower than the set frequency to pass through. It has all the advantages of the filter device described in one, two, or three of the filter device embodiments or the conductor described in the conductor embodiment.

[0107] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application, all of which fall within the scope of protection of this application.

Claims

1. A filtering device, characterized in that, Used to filter AC components with frequencies higher than a set frequency, including: magnetic conductors; The magnetic conductor comprises a solid mixture of a first substance and a second substance, wherein the electrical conductivity of the first substance is less than that of the second substance, and the magnetic permeability of the first substance is greater than a first set value. The width of the cross-section of the magnetic conductor in any direction from the center point of the cross-section is greater than twice the skin depth of the magnetic conductor to the AC component of the set frequency, and the resistance of the magnetic conductor to the DC component is less than or equal to 50 ohms.

2. The filtering device according to claim 1, characterized in that, The length of the magnetic conductor is obtained based on the skin depth, cross-sectional perimeter, conductivity of the magnetic conductor, and impedance requirements for AC signals above the set frequency.

3. The filtering device according to claim 1, characterized in that, The first and second substances are uniformly distributed in the magnetic conductor, and its magnetic permeability is equal to the weighted average of the magnetic permeability of the first and second substances in the mixture based on the component ratio, and its electrical conductivity is equal to the weighted average of the electrical conductivity of the first and second substances based on the component ratio.

4. A filtering device, characterized in that, For filtering AC components with frequencies higher than a set frequency, it includes: a magnetic conductor, wherein the magnetic conductor has a multi-layer structure, and the conductivity of each layer gradually increases from the outside to the inside; The magnetic conductor, except for the innermost layer, comprises a solid mixture of a first substance and a second substance in each layer. The electrical conductivity of the first substance is less than that of the second substance, and the magnetic permeability of the first substance is greater than a first set value. The innermost layer is a solid substance composed of a second substance or a solid mixture composed of a first substance and a second substance, with the proportion of the second substance being greater than that of the other layers. The outermost layer of the magnetic conductor has a cross-sectional width greater than twice the skin depth of the layer to the AC component of the set frequency, and the innermost layer of the magnetic conductor has a resistance to the DC component of less than or equal to 50 ohms.

5. The filtering device according to claim 4, characterized in that, In each layer of the magnetic conductor, the first and second materials are uniformly distributed; From the outside in, the proportion of the first material in each layer of the magnetic conductor decreases and the proportion of the second material increases.

6. The filtering device according to claim 4, characterized in that, The permeability of each layer of the magnetic conductor is equal to the weighted average of the permeability of the first and second materials in that layer based on the composition ratio, and the conductivity of each layer of the magnetic conductor is equal to the weighted average of the conductivity of the first and second materials in that layer based on the composition ratio.

7. The filtering device according to claim 4, characterized in that, The equivalent permeability of each layer in the magnetic conductor, except for the outermost layer, is obtained based on the permeability and cross-sectional area of ​​that layer and all layers outward from it. The equivalent permeability of the outermost layer is equal to the permeability of that layer.

8. The filtering device according to claim 4, characterized in that, A third material is inserted into any two layers of the magnetic conductor. This third material is a solid object composed of a third material that is non-conductive and has a magnetic permeability greater than a second predetermined value.

9. A conductor, characterized in that, Includes the magnetic conductor in any of the filter devices described in claims 1 to 8.

10. A filtering method, characterized in that, The AC component with a frequency higher than a set frequency is filtered by any of the filter devices described in claims 1 to 8 or by the conductor described in claim 9.

Images