An alternating current porcelain dielectric capacitor with filtering function

Abstract

This invention proposes an AC ceramic capacitor with filtering function, relating to the technical field of AC ceramic capacitors with filtering capabilities. Because the high-capacitance ceramic capacitor can filter out low-frequency noise below 1MHz in the circuit, and the low-inductance ferrite beads can suppress mid-frequency interference, the combination of the low-capacitance ceramic capacitor and the high-frequency inductor can create a steep attenuation in the circuit and filter out noise above 1MHz. Therefore, the first-stage circuit and the second-stage circuit can filter out low-frequency and mid-frequency interference and high-frequency interference respectively. Furthermore, the frequency band is separated by the characteristic of the first-stage and second-stage circuits forming a double-cascaded circuit, avoiding the limitations of the resonant point in a single resonant circuit and widening the effective filtering bandwidth, achieving excellent filtering characteristics. This application is applicable to applications such as 5G base station power input filtering and EMI suppression at the AC end of electric vehicle on-board chargers. Traditional LC filters are mostly single-stage or symmetrical designs.

Description

Technical Field

[0001] This utility model relates to the field of AC ceramic capacitors with filtering capabilities, specifically an AC ceramic capacitor with filtering function. Background Technology

[0002] AC ceramic capacitors are electronic components used in circuits to perform functions such as filtering, coupling, and bypassing. They are characterized by their small size, large capacitance, and suitability for high-frequency circuit applications, and are commonly found in mobile phones, computers, automotive electronics, and other devices. During production, AC ceramic capacitors are typically formed into a single unit through high-temperature sintering (the number of internal layers varies from tens to hundreds, with interlayer connections via terminal electrodes; its structure consists of alternating layers of ceramic dielectric and metal electrodes).

[0003] Existing AC ceramic capacitors do not have filtering capabilities, which means they cannot effectively eliminate stray signals in circuits. This is particularly evident when AC ceramic capacitors are used in circuits, because traditional filtering designs often use LC passive filters or RC active filters, but these solutions have significant shortcomings in terms of wideband noise suppression, temperature stability, and long-term reliability.

[0004] Therefore, this application proposes an AC ceramic capacitor with filtering function. Utility Model Content

[0005] The purpose of this invention is to provide an AC ceramic capacitor with filtering function to solve the problems mentioned in the background art and overcome its technical defects.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: an AC ceramic capacitor with filtering function, comprising a dual-cascade circuit, wherein the dual-cascade circuit includes a high-capacitance ceramic capacitor, a low-capacitance ceramic capacitor, a low-inductance ferrite bead, and a high-frequency inductor, wherein the high-capacitance ceramic capacitor and the low-inductance ferrite bead form a first-stage circuit, and the low-capacitance ceramic capacitor and the high-frequency inductor form a second-stage circuit, the first-stage circuit and the second-stage circuit together forming a dual-cascade circuit; an NTC thermistor, wherein the NTC thermistor is connected in parallel between the high-capacitance ceramic capacitor and the low-capacitance ceramic capacitor for dynamic adjustment of the circuit capacitance; and a protective component, wherein the protective component is disposed inside the high-capacitance ceramic capacitor and the low-capacitance ceramic capacitor for protection during use.

[0007] As a further embodiment of this utility model: an AC ceramic capacitor with filtering function, wherein the high-capacitance ceramic capacitor is a ceramic capacitor with a range of 100nF, and the low-capacitance ceramic capacitor is a multi-ceramic capacitor with a range of 1nF.

[0008] As a further embodiment of this utility model: an AC ceramic capacitor with filtering function, wherein the low-inductance ferrite bead is an inductor with a range of 100nH and the high-frequency inductor is an inductor with a range of 10μH.

[0009] As a further embodiment of this utility model: an AC ceramic capacitor with filtering function, further comprising a first Y-type capacitor and a second Y-type capacitor, wherein the first Y-type capacitor and the second Y-type capacitor are arranged in a cascaded circuit and form a common-mode filtering path circuit.

[0010] As a further embodiment of this utility model: an AC ceramic capacitor with filtering function, wherein both the high-capacitance ceramic capacitor and the low-capacitance ceramic capacitor have a filling layer inside, and the filling layer is made of PFA insulating material.

[0011] As a further embodiment of this utility model: an AC ceramic capacitor with filtering function, wherein the pins of both the high-capacitance and low-capacitance ceramic capacitors are wrapped with a flame-retardant layer, the flame-retardant layer being made of silicon oxide material.

[0012] Compared with the prior art, the beneficial effects of this utility model include:

[0013] Because high-capacitance ceramic capacitors can filter out low-frequency noise less than 1MHz in the circuit, and low-inductance ferrite beads can suppress mid-frequency interference in the circuit, the combination of low-capacitance ceramic capacitors and high-frequency inductors can form a steep attenuation in the circuit and filter out noise above 1MHz. Therefore, the first-stage circuit and the second-stage circuit can filter out mid-low frequency interference and high-frequency interference respectively. By using the characteristic of the first-stage circuit and the second-stage circuit to form a double-cascaded circuit, the frequency band can be separated, which can avoid the limitation of the resonant point in a single resonant circuit and broaden the effective filtering bandwidth to achieve excellent filtering characteristics. This application is applicable to the application scenarios of 5G base station power input filtering and EMI suppression at the AC end of electric vehicle on-board chargers. In addition, traditional LC filters are mostly single-stage or symmetrical designs.

[0014] Because the NTC thermistor is connected in parallel between the high-capacitance and low-capacitance ceramic capacitors to enable dynamic adjustment of the circuit capacitance, the equivalent impedance of the capacitors in the cascaded circuit can be dynamically adjusted by connecting the NTC thermistor in parallel between the high-capacitance and low-capacitance ceramic capacitors. This counteracts the effect of temperature changes on the capacitance of the ceramic capacitors and ensures that the circuit maintains stable filtering characteristics within the range of -40 to 125 degrees Celsius.

[0015] Since both high-capacitance and low-capacitance ceramic capacitors have an internal filling layer made of PFA insulating material, and both have a flame-retardant layer made of silicon oxide wrapped around their leads, the protective components can prevent high-temperature fires caused by overload during use, thus reducing the probability of fire. Attached Figure Description

[0016] The disclosure of this utility model is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this utility model. In the drawings, the same reference numerals are used to refer to the same parts. Wherein:

[0017] Figure 1 A circuit diagram according to one embodiment of the present invention is shown schematically;

[0018] Figure 2 The diagram schematically shows a cross-sectional view of a protective member according to one embodiment of the present invention;

[0019] The following are the labels in the diagram: 1. Cascaded circuit; 2. High-capacitance ceramic capacitor; 3. Low-capacitance ceramic capacitor; 4. Low-inductance ferrite bead; 5. High-frequency inductor; 6. NTC thermistor; 7. First Y-type capacitor; 8. Second Y-type capacitor; 9. Filler layer; 10. Flame retardant layer. Detailed Implementation

[0020] It is readily understood that, based on the technical solution of this utility model, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of this utility model. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative descriptions of the technical solution of this utility model and should not be considered as the entirety of this utility model or as limitations or restrictions on the technical solution of this utility model.

[0021] According to an embodiment of the present invention, an AC ceramic capacitor with filtering function is shown in conjunction with the accompanying drawings. It includes a dual-cascade circuit 1, comprising a high-capacitance ceramic capacitor 2, a low-capacitance ceramic capacitor 3, a low-inductance ferrite bead 4, and a high-frequency inductor 5. The high-capacitance ceramic capacitor 2 is a 100nF ceramic capacitor, the low-capacitance ceramic capacitor 3 is a multi-ceramic capacitor with a 1nF range, the low-inductance ferrite bead 4 is an inductor with a 100nH range, and the high-frequency inductor 5 is an inductor with a 10μH range. The high-capacitance ceramic capacitor 2 and the low-inductance ferrite bead 4 form the first-stage circuit. The high-capacitance ceramic capacitor 2 can filter out low-frequency noise less than 1MHz in the circuit, and the low-inductance ferrite bead 4 can... The low-capacitance ceramic capacitor 3 and the high-frequency inductor 5 form a second-stage circuit to suppress intermediate-frequency interference in the circuit. The combination of the low-capacitance ceramic capacitor 3 and the high-frequency inductor 5 can form a steep attenuation of the circuit and filter out noise above 1MHz. Therefore, the first-stage circuit and the second-stage circuit in this application can filter out low-frequency and high-frequency interference respectively. By using the characteristic of the first-stage circuit and the second-stage circuit to form a double-cascaded circuit 1, the frequency band is separated, which can avoid the limitation of the resonant point in a single resonant circuit and broaden the effective filtering bandwidth to achieve excellent filtering characteristics. This application is applicable to the application scenarios of 5G base station power input filtering and electric vehicle on-board charger OBCAC terminal EMI suppression. In addition, traditional LC filters are mostly single-stage or symmetrical designs.

[0022] The NTC thermistor 6, with a range of 10kΩ and a B value of 3435, is connected in parallel between the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 to provide dynamic adjustment of the circuit capacitance. By connecting the NTC thermistor 6 in parallel between the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3, the equivalent impedance of the capacitor in the double-cascade circuit 1 can be dynamically adjusted to counteract the influence of temperature changes on the capacitance of the ceramic capacitor, thus ensuring that the circuit maintains stable filtering characteristics within the range of -40 to 125 degrees Celsius.

[0023] The protective component is installed inside the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 to protect them during use. Both the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 have a filling layer 9 made of PFA insulating material. The leads of both the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 are wrapped with a flame-retardant layer 10 made of silicon oxide. Therefore, the protective component can protect the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 from overload and high-temperature fire during use, reducing the probability of a fire.

[0024] As a further solution of this utility model: an AC ceramic capacitor with filtering function, further comprising a first Y-type capacitor 7 and a second Y-type capacitor 8, wherein the first Y-type capacitor 7 and the second Y-type capacitor 8 are disposed in a dual-cascade circuit 1 and form a common-mode filtering path circuit, the main filtering circuit composed of the first-stage circuit and the second-stage circuit focuses on differential-mode noise, and the Y-type capacitor handles common-mode interference, thereby achieving full noise type coverage.

[0025] Working Principle: The dual-cascade circuit 1 of this application includes a high-capacitance ceramic capacitor 2, a low-capacitance ceramic capacitor 3, a low-inductance ferrite bead 4, and a high-frequency inductor 5. The high-capacitance ceramic capacitor 2 is a ceramic capacitor with a range of 100nF, the low-capacitance ceramic capacitor 3 is a multi-ceramic capacitor with a range of 1nF, the low-inductance ferrite bead 4 is an inductor with a range of 100nH, and the high-frequency inductor 5 is an inductor with a range of 10μH. The high-capacitance ceramic capacitor 2 and the low-inductance ferrite bead 4 form the first-stage circuit. The high-capacitance ceramic capacitor 2 can filter out low-frequency noise less than 1MHz in the circuit, and the low-inductance ferrite bead 4 can suppress intermediate-frequency interference in the circuit. The low-capacitance ceramic capacitor 3 and the high-frequency inductor 5 form the second-stage circuit. The combination of the low-capacitance ceramic capacitor 3 and the high-frequency inductor 5 can form a steep attenuation of the circuit and filter out noise above 1MHz. Therefore, the first-stage circuit and the second-stage circuit in this application can filter out low-frequency interference and high-frequency interference respectively. By using the characteristic of the first-stage circuit and the second-stage circuit to form a double-cascaded circuit 1, the frequency band is separated, which can avoid the limitation of the resonant point in a single resonant circuit and broaden the effective filtering bandwidth to achieve excellent filtering characteristics. This application is applicable to the application scenarios of 5G base station power input filtering and electric vehicle on-board charger OBCAC terminal EMI suppression. In addition, traditional LC filters are mostly single-stage or symmetrical designs.

[0026] In addition, the NTC thermistor 6 of this application has a range of 10kΩ and a B value of 3435. It is connected in parallel between the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 to provide dynamic adjustment of the circuit capacitance. By connecting the NTC thermistor 6 in parallel between the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3, the equivalent impedance of the capacitor in the double-cascade circuit 1 can be dynamically adjusted to counteract the influence of temperature changes on the capacitance of the ceramic capacitor, and ensure that the circuit maintains stable filtering characteristics in the range of -40 to 125 degrees Celsius.

[0027] Meanwhile, protective components are installed inside the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 to protect them during use. Both the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 have a filling layer 9 inside, made of PFA insulating material. The leads of both the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 are wrapped with a flame-retardant layer 10 made of silicon oxide. Therefore, the protective components can prevent the high-capacitance ceramic capacitor 2 and the low-capacitance ceramic capacitor 3 from overloading and causing high-temperature fires during use, reducing the probability of fire.

[0028] The technical scope of this utility model is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this utility model, and all such modifications and variations should fall within the protection scope of this utility model.

Claims

1. An AC ceramic capacitor with filtering function, characterized in that, The circuit includes a cascaded circuit (1), which includes a high-capacitance ceramic capacitor (2), a low-capacitance ceramic capacitor (3), a low-inductance ferrite bead (4), and a high-frequency inductor (5). The high-capacitance ceramic capacitor (2) and the low-inductance ferrite bead (4) form the first stage circuit, and the low-capacitance ceramic capacitor (3) and the high-frequency inductor (5) form the second stage circuit. The first stage circuit and the second stage circuit together form the cascaded circuit (1). NTC thermistor (6), which is connected in parallel between the high-capacitance ceramic capacitor (2) and the low-capacitance ceramic capacitor (3) and provides for dynamic adjustment of the circuit capacitance. as well as The protective component is disposed inside the high-capacitance ceramic capacitor (2) and the low-capacitance ceramic capacitor (3) and provides protection for the high-capacitance ceramic capacitor (2) and the low-capacitance ceramic capacitor (3).

2. The AC ceramic capacitor with filtering function according to claim 1, characterized in that, The high-capacitance ceramic capacitor (2) is a ceramic capacitor with a range of 100nF, and the low-capacitance ceramic capacitor (3) is a multi-ceramic capacitor with a range of 1nF.

3. The AC ceramic capacitor with filtering function according to claim 2, characterized in that, The low-inductance ferrite bead (4) is an inductor with a range of 100nH, and the high-frequency inductor (5) is an inductor with a range of 10μH.

4. The AC ceramic capacitor with filtering function according to claim 3, characterized in that, It also includes a first Y-type capacitor (7) and a second Y-type capacitor (8), which are arranged in the dual-cascade circuit (1) and form a common-mode filter path circuit.

5. An AC ceramic capacitor with filtering function according to claim 4, characterized in that, Both the high-capacitance ceramic capacitor (2) and the low-capacitance ceramic capacitor (3) have a filling layer (9) inside, and the filling layer (9) is made of PFA insulating material.

6. An AC ceramic capacitor with filtering function according to claim 5, characterized in that, The pins of both the high-capacitance ceramic capacitor (2) and the low-capacitance ceramic capacitor (3) are covered with a flame-retardant layer (10), which is made of silicon oxide material.

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