CN215734202U

CN215734202U - EMI cable filter

Info

Publication number: CN215734202U
Application number: CN202122128594.2U
Authority: CN
Inventors: 郭华; 梁玉池
Original assignee: Vertiv Tech Co Ltd
Current assignee: Vertiv Tech Co Ltd
Priority date: 2021-09-03
Filing date: 2021-09-03
Publication date: 2022-02-01
Anticipated expiration: 2031-09-03

Abstract

An EMI cable filter comprises a common-mode inductor connected in series on a twin cable, wherein a first common-mode inductor coil of the common-mode inductor is connected in series in a first cable of the twin cable, and a second common-mode inductor coil of the common-mode inductor is connected in series in a second cable of the twin cable. According to the EMI cable filter, the common-mode inductor is arranged on the cable, so that the PCB space is not occupied, the size of the PCB is reduced, the space utilization rate is improved, the common-mode inductor is far away from an interference source, the influence of near-field coupling on the filtering performance is reduced, and the EMI filtering effect is improved.

Description

EMI cable filter

Technical Field

The present invention relates to the field of electromagnetic interference (EMI) filtering, and more particularly, to an EMI cable filter.

Background

Typically, EMI filters are implemented on a Printed Circuit Board (PCB). However, as electronic products are required to have higher volume, power density and space utilization, the interference generated in the electronic products is stronger, so the EMI filter disposed on the PCB is often interfered by other circuits or devices and cannot work normally.

SUMMERY OF THE UTILITY MODEL

The technical problem to be solved by the present invention is to provide an EMI cable filter, which is disposed on a cable, so as to occupy no PCB space, reduce the size of the PCB, improve the space utilization, and keep away from an interference source, reduce the influence of near-field coupling on the performance of the filter, and improve the EMI filtering effect.

The technical scheme adopted by the utility model for solving the technical problems is as follows: an EMI cable filter is constructed, and comprises a common-mode inductor connected in series on a twin cable, wherein a first common-mode inductor coil of the common-mode inductor is connected in series in a first cable of the twin cable, and a second common-mode inductor coil of the common-mode inductor is connected in series in a second cable of the twin cable.

In the EMI cable filter of the present invention, the common mode inductor is externally wrapped with a magnetic shielding material.

In the EMI cable filter of the present invention, the first cable and the second cable are respectively sleeved with a first magnetic bead and a second magnetic bead, and the first magnetic bead and the second magnetic bead are disposed opposite to each other.

In the EMI cable filter of the present invention, the common mode capacitor is connected between the first cable and the ground and between the second cable and the ground.

In the EMI cable filter of the present invention, further comprising a differential mode capacitor connected across the first cable and the second cable.

In the EMI cable filter of the present invention, the common mode inductor includes an R5K common mode inductor, an R7K common mode inductor, an R10K common mode inductor, or a nickel zinc ferrite common mode inductor, and the common mode inductor is a common mode inductor after insulation treatment by a heat shrink sleeve.

In the EMI cable filter of the present invention, the common mode inductor includes an amorphous or ultra-microcrystalline magnetic core, and the first common mode inductor coil and the second common mode inductor coil wound around the amorphous or ultra-microcrystalline magnetic core.

In the EMI cable filter, the twin cable is connected with a power supply input port of a complete machine power supply and a power supply input port of a PCBA (printed Circuit Board Assembly) in the machine.

Another technical solution adopted by the present invention to solve the technical problem is to construct an EMI cable filter, including a common mode inductor, a first magnetic bead and a second magnetic bead connected in series in a duplex cable, where a first common mode inductor coil of the common mode inductor is connected in series in a first cable of the duplex cable, a second common mode inductor coil of the common mode inductor is connected in series in a second cable of the duplex cable, the first magnetic bead is sleeved on the first cable, the second magnetic bead is sleeved on the second cable, the first magnetic bead and the second magnetic bead are arranged opposite to each other, and the duplex cable is connected to a power input port of a power supply of a whole machine and a power input port of a PCBA power supply in the machine.

In the EMI cable filter of the present invention, the common mode inductor is externally wrapped with a magnetic shielding material, a common mode capacitance is connected between the first cable and the ground, a differential mode capacitance is connected between the second cable and the ground, and a differential mode capacitance is connected between the first cable and the second cable.

According to the EMI cable filter, the common-mode inductor is arranged on the cable, so that the PCB space is not occupied, the size of the PCB is reduced, the space utilization rate is improved, the common-mode inductor is far away from an interference source, the influence of near-field coupling on the filtering performance is reduced, and the EMI filtering effect is improved. Further, beads may be arranged for further filtering. Furthermore, a magnetic shielding material can be wrapped outside the common-mode inductor to shield the interference of an internal electromagnetic field to the common-mode inductor, so that the influence of near-field coupling is further reduced, and the performance of the common-mode inductor is ensured. Still further, common mode capacitance and/or differential mode capacitance may be provided to promote insertion loss.

Drawings

The utility model will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic block diagram of a preferred embodiment of an EMI cable filter of the present invention;

FIG. 2 is a schematic block diagram of yet another preferred embodiment of the EMI cable filter of the present invention;

FIG. 3 is a schematic diagram of the results of a conducted test of an EMI cable filter incorporating the present invention;

fig. 4 is a graphical representation of the results of a conduction test of an EMI cable filter without the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the utility model and are not intended to limit the utility model.

Fig. 1 is a schematic structural diagram of a preferred embodiment of the EMI cable filter of the present invention. As shown in fig. 1, the EMI cable filter includes a common mode inductor 10 connected in series in a twin cable 40. The double-strand cable 40 is connected with the power input port 20 of the power supply of the whole machine and the power input port 30 of the PCBA in the machine. The first common mode inductor coil 11 of the common mode inductor 10 is connected in series in the first cable 41 of the duplex cable 40, and the second common mode inductor coil 13 of the common mode inductor 10 is connected in series in the second cable 42 of the duplex cable 40.

Since the common mode inductor 10 itself has a large common mode impedance to suppress common mode noise, and its differential mode component can also suppress differential mode noise, EMI filtering can be achieved. And because the common mode inductor 10 is connected in series in the twin cable 40, rather than being arranged on a PCB board inside the power supply, it does not occupy the PCB space, can reduce the size of the PCB, and improves the space utilization. And the double-stranded cable 40 is arranged, so that the double-stranded cable can be far away from each interference source on a PCB, the influence of near-field coupling on the filtering performance is reduced, and the EMI filtering effect is improved.

The common mode inductor 10 may be an R5K common mode inductor, an R7K common mode inductor, an R10K common mode inductor, or a nickel zinc ferrite common mode inductor, which is determined according to the required inductance and noise frequency. The core 12 of the common mode inductor 10 may be made of any suitable material, such as an amorphous or ultra-microcrystalline core, and the first common mode inductor coil 11 and the second common mode inductor coil 13 are wound around the amorphous or ultra-microcrystalline core. The common mode inductor 10 may be insulated by using a heat shrinkable sleeve to improve the insulation performance.

Fig. 2 is a schematic structural diagram of yet another preferred embodiment of the EMI cable filter of the present invention. As shown in fig. 2, the EMI cable filter includes a common mode inductor 10, a first magnetic bead 51, and a second magnetic bead 52 connected in series in a twin cable 40. The common mode inductor 10 is externally wrapped with a magnetic shielding material 60. In the preferred embodiment, two first magnetic beads 51 are provided on the first cable 41, and two second magnetic beads 52 are provided on the second cable 42. The two first magnetic beads 51 and the two second magnetic beads 52 are respectively arranged oppositely. Of course, in other preferred embodiments of the present invention, a different number of magnetic beads may be provided, or no magnetic beads may be provided.

Similar to the embodiment shown in fig. 1, the duplex cable 40 connects the power input port 20 of the overall power supply and the power input port 30 of the PCBA within the machine. The first common mode inductor coil 11 of the common mode inductor 10 is connected in series in the first cable 41 of the duplex cable 40, and the second common mode inductor coil 13 of the common mode inductor 10 is connected in series in the second cable 42 of the duplex cable 40. The common mode inductor 10 may be an R5K common mode inductor, an R7K common mode inductor, an R10K common mode inductor, or a nickel zinc ferrite common mode inductor, which is determined according to the required inductance and noise frequency. The core 12 of the common mode inductor 10 may be made of any suitable material, such as an amorphous or ultra-microcrystalline core, and the first common mode inductor coil 11 and the second common mode inductor coil 13 are wound around the amorphous or ultra-microcrystalline core. The common mode inductor 10 may be insulated by using a heat shrinkable sleeve to improve the insulation performance.

In the preferred embodiment, a common mode inductor and a magnetic bead are integrated on the twisted pair cable 40 between the power input port 20 of the complete machine power supply and the power input port 30 of the PCBA in the machine, the common mode inductor has a large common mode impedance to suppress common mode noise, the differential mode component of the common mode inductor can suppress differential mode noise, and the magnetic bead can suppress high-frequency radiation noise. The common mode inductor 10 is wrapped with the magnetic shielding material 60, so that interference of an external magnetic field on the common mode inductor can be shielded, the influence of near field coupling is further reduced, and the performance of the common mode inductor is ensured. Here, the length of the twisted pair cable 40 and the size of the common mode inductor 10 are adjustable to meet different product requirements.

Fig. 3 is a schematic diagram of the results of a conducted test of an EMI cable filter equipped with the present invention. Fig. 4 is a graphical representation of the results of a conduction test of an EMI cable filter without the present invention. Referring to fig. 3 and 4, after the EMI cable filter of the present invention is disposed, EMI noise is significantly reduced, and the EMI filtering effect is very good.

Of course, as mentioned above, the common mode inductor 10 may not be shielded, and in a case of a small space, the filtering effect will be reduced due to the influence of the near field. In a further preferred embodiment of the present invention, the EMI cable filter may further include a differential mode capacitance connected across the first cable 41 and the second cable 42, and a common mode capacitance connected across the first cable 41 and the ground and the second cable 42 and the ground, thereby increasing an insertion loss.

According to the EMI cable filter, the common-mode inductor is arranged on the cable, so that the PCB space is not occupied, the size of the PCB is reduced, the space utilization rate is improved, the common-mode inductor is far away from an interference source, the influence of near-field coupling on the filtering performance is reduced, and the EMI filtering effect is improved. Further, beads may be arranged for further filtering. Furthermore, a magnetic shielding material can be wrapped outside the common-mode inductor to shield the interference of an internal magnetic field to the common-mode inductor, so that the influence of near-field coupling is further reduced, and the performance of the common-mode inductor is ensured. Still further, common mode capacitance and/or differential mode capacitance may be provided to promote insertion loss.

While the utility model has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the utility model. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the utility model without departing from its scope. Therefore, it is intended that the utility model not be limited to the particular embodiment disclosed, but that the utility model will include all embodiments falling within the scope of the appended claims.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the utility model, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. An EMI cable filter, comprising a common-mode inductor connected in series to a twisted pair cable, wherein a first common-mode inductor coil of the common-mode inductor is connected in series to a first cable of the twisted pair cable, and a second common-mode inductor coil of the common-mode inductor is connected in series to a second cable of the twisted pair cable.

2. The EMI cable filter of claim 1 wherein the common mode inductor is externally wrapped with a magnetic shielding material.

3. The EMI cable filter of claim 1, wherein the first and second cables are respectively sleeved with first and second magnetic beads, and the first and second magnetic beads are disposed opposite to each other.

4. The EMI cable filter of claim 1 further comprising a common mode capacitance connected across the first cable and ground and the second cable and ground.

5. The EMI cable filter of any one of claims 1-4, further comprising a differential mode capacitance connected across the first cable and the second cable.

6. The EMI cable filter of claim 1, wherein the common-mode inductor comprises a R5K type common-mode inductor, a R7K type common-mode inductor, a R10K type common-mode inductor, or a nickel-zinc ferrite common-mode inductor, and the common-mode inductor is a common-mode inductor after heat shrink sleeve insulation.

7. The EMI cable filter of claim 1 wherein the common-mode inductor comprises an amorphous or ultra-microcrystalline magnetic core and the first and second common-mode inductors are wound around the amorphous or ultra-microcrystalline magnetic core.

8. The EMI cable filter of claim 1 wherein the two-strand cable connects the power input port of the overall power supply and the built-in PCBA power input port.

9. The EMI cable filter is characterized by comprising a common-mode inductor, a first magnetic bead and a second magnetic bead which are connected in series on a double-strand cable, wherein a first common-mode inductor coil of the common-mode inductor is connected in series in a first cable of the double-strand cable, a second common-mode inductor coil of the common-mode inductor is connected in series in a second cable of the double-strand cable, the first magnetic bead is sleeved on the first cable, the second magnetic bead is sleeved on the second cable, the first magnetic bead and the second magnetic bead are opposite to each other, and the double-strand cable is connected with a power input port of a complete machine power supply and a power input port of the PCBA power supply.

10. The EMI cable filter of claim 9 wherein the common mode inductor is externally wrapped with a magnetic shielding material, a common mode capacitance is connected between the first cable and ground, a second cable and ground, and a differential mode capacitance is connected between the first cable and the second cable.