CN218549876U - EMI filter circuit - Google Patents
EMI filter circuit Download PDFInfo
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- CN218549876U CN218549876U CN202222589400.3U CN202222589400U CN218549876U CN 218549876 U CN218549876 U CN 218549876U CN 202222589400 U CN202222589400 U CN 202222589400U CN 218549876 U CN218549876 U CN 218549876U
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- common mode
- differential mode
- magnetic bead
- electric capacity
- capacitor
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Abstract
The utility model discloses an EMI filter circuit, it includes power input end, the power output end, differential mode inductance L1, differential mode inductance L2, differential mode electric capacity C1, differential mode electric capacity C2, common mode electric capacity C3, common mode electric capacity C4, common mode inductance L3, magnetic bead L4, magnetic bead L5, differential mode inductance L1 one end connection power positive input end, the other end is connected with differential mode electric capacity C1 one end, the first input end of common mode inductance L3, differential mode inductance L2 one end connection power negative input end, the other end is connected with the differential mode electric capacity C1 other end, the second input end of common mode inductance L3; the first output end of the common mode inductor L3 is connected with one end of a differential mode capacitor C2, one end of the common mode capacitor C3 and one end of a magnetic bead L4, the second output end of the common mode inductor L3 is connected with the other end of the differential mode capacitor C2, one end of the common mode capacitor C4 and one end of the magnetic bead L5, the other ends of the common mode capacitor C3 and the common mode capacitor C4 are grounded, and the other ends of the magnetic bead L4 and the magnetic bead L5 are connected with the positive output end and the negative output end of a power supply respectively. The utility model discloses a parameter adjustment realizes filtering intrinsic switching frequency.
Description
Technical Field
The utility model belongs to the technical field of the wave filter technique and specifically relates to a EMI wave filter circuit is related to.
Background
The EMI filter is a passive filter composed of a passive device capacitor, a differential-common mode inductor and a resistor, is mainly applied to the design of a switching power supply, can effectively inhibit conducted emission interference on a switching power supply line, and solves the problems related to the electromagnetic interference of the switching power supply. In typical switching power supply applications, the switching frequency is typically a fixed frequency in the range of 200kHz to 400 kHz. The filter is affected by the working frequency of the magnetic ring, the noise suppression effect after 20MHz is weakened generally, and even the filter cannot play a role in filtering. When the RE102 is tested, a high-frequency interference signal after 30MHz exists on a power supply line, so that the RE102 cannot be tested.
Disclosure of Invention
In order to solve the above problems, an object of the present invention is to provide an EMI filter circuit, which has a magnetic bead connected in series on the positive and negative lines of the power supply according to the frequency of the interference signal, and can suppress the high frequency signal, thereby improving the high frequency characteristic of the EMI filter.
In order to achieve the purpose, the utility model adopts the following technical proposal:
an EMI filter circuit comprises a power input end, a power output end, a differential mode inductor L1, a differential mode inductor L2, a differential mode capacitor C1, a differential mode capacitor C2, a common mode capacitor C3, a common mode capacitor C4, a common mode inductor L3, a magnetic bead L4 and a magnetic bead L5, wherein one end of the differential mode inductor L1 is connected with a positive input end of a power supply, the other end of the differential mode inductor L1 is connected with one end of the differential mode capacitor C1 and a first input end of the common mode inductor L3, one end of the differential mode inductor L2 is connected with a negative input end of the power supply, and the other end of the differential mode inductor L2 is connected with the other end of the differential mode capacitor C1 and a second input end of the common mode inductor L3; common mode inductance L3's first output is connected with differential mode electric capacity C2 one end, common mode electric capacity C3 one end, magnetic bead L4 one end, and the second output is connected with the differential mode electric capacity C2 other end, common mode electric capacity C4 one end, magnetic bead L5 one end, and common mode electric capacity C3, the common mode electric capacity C4 other end all ground connection, and the magnetic bead L4 other end, the magnetic bead L5 other end are connected power positive output end, power negative output end respectively.
Due to the adoption of the technical scheme, the utility model discloses have following superiority:
the EMI filter circuit adopts magnetic beads with higher resistivity and magnetic conductivity, is equivalent to series connection of a resistor and an inductor, has better filtering characteristics than common inductors, presents resistance at high frequency, and keeps higher impedance in a wide range, thereby improving the filtering effect of a high frequency band; the filtering of the inherent switching frequency is realized through parameter adjustment, so that the requirement of a CE102 conduction test is met, high-frequency noise on a power line is suppressed, and the RE102 test effect is improved.
Drawings
Fig. 1 is a schematic diagram of an EMI filter circuit according to the present invention.
Detailed Description
The technical solution of the present invention will be further described in detail with reference to the accompanying drawings and embodiments.
As shown IN fig. 1, the EMI filter circuit includes a power input terminal, a power output terminal, a differential mode inductor L1, a differential mode inductor L2, a differential mode capacitor C1, a differential mode capacitor C2, a common mode capacitor C3, a common mode capacitor C4, a common mode inductor L3, a magnetic bead L4, and a magnetic bead L5, wherein one end of the differential mode inductor L1 is connected to a positive power input terminal (IN +), the other end is connected to one end of the differential mode capacitor C1 and a first input terminal of the common mode inductor L3, one end of the differential mode inductor L2 is connected to a negative power input terminal (IN-), and the other end is connected to the other end of the differential mode capacitor C1 and a second input terminal of the common mode inductor L3; the first output end of the common mode inductor L3 is connected with one end of a differential mode capacitor C2, one end of a common mode capacitor C3 and one end of a magnetic bead L4, the second output end of the common mode inductor is connected with the other end of the differential mode capacitor C2, one end of the common mode capacitor C4 and one end of the magnetic bead L5, the other ends of the common mode capacitor C3 and the common mode capacitor C4 are grounded, and the other end of the magnetic bead L4 and the other end of the magnetic bead L5 are respectively connected with a positive output end (OUT +) of a power supply and a negative output end (OUT-).
The utility model discloses EMI wave filter circuit, it is two-stage filter circuit, has common mode filtering and differential mode filtering function, can restrain the difference mode and common mode interference of broadband 10 kHz-20 MHz on the power cord; the high-frequency characteristics of the magnetic beads L4 and L5 can have a suppression effect on high-frequency noise of 20MHz, thereby achieving the suppression of conduction and radiation interference of the power supply line.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (1)
1. An EMI filter circuit, comprising: the power supply comprises a power supply input end, a power supply output end, a differential mode inductor L1, a differential mode inductor L2, a differential mode capacitor C1, a differential mode capacitor C2, a common mode capacitor C3, a common mode capacitor C4, a common mode inductor L3, a magnetic bead L4 and a magnetic bead L5, wherein one end of the differential mode inductor L1 is connected with a positive input end of the power supply, the other end of the differential mode inductor L1 is connected with one end of the differential mode capacitor C1 and a first input end of the common mode inductor L3, one end of the differential mode inductor L2 is connected with a negative input end of the power supply, and the other end of the differential mode inductor L2 is connected with the other end of the differential mode capacitor C1 and a second input end of the common mode inductor L3; common mode inductance L3's first output and differential mode electric capacity C2 one end, common mode electric capacity C3 one end, magnetic bead L4 one end are connected, and the second output is connected with the differential mode electric capacity C2 other end, common mode electric capacity C4 one end, magnetic bead L5 one end, and common mode electric capacity C3, the common mode electric capacity C4 other end all ground connection, and the magnetic bead L4 other end, the magnetic bead L5 other end are connected positive output terminal of power, power negative output terminal respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222589400.3U CN218549876U (en) | 2022-09-29 | 2022-09-29 | EMI filter circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222589400.3U CN218549876U (en) | 2022-09-29 | 2022-09-29 | EMI filter circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN218549876U true CN218549876U (en) | 2023-02-28 |
Family
ID=85274515
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202222589400.3U Active CN218549876U (en) | 2022-09-29 | 2022-09-29 | EMI filter circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN218549876U (en) |
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2022
- 2022-09-29 CN CN202222589400.3U patent/CN218549876U/en active Active
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