CN210898924U

CN210898924U - Common mode inductor is with filtering common mode interference mechanism

Info

Publication number: CN210898924U
Application number: CN201921947418.8U
Authority: CN
Inventors: 黄明
Original assignee: Ningbo Rongjijin Technology Co ltd
Current assignee: Ningbo Rongjijin Technology Co ltd
Priority date: 2019-11-13
Filing date: 2019-11-13
Publication date: 2020-06-30
Anticipated expiration: 2029-11-13

Abstract

The utility model provides a common mode inductor is with filtering common mode interference mechanism, including circuit board, PCB I, PCB II, filter circuit, inductance, electric capacity I and electric capacity II, the utility model discloses filter circuit's setting, product output signal ripple is obvious less (about 20mV), and voltage is stable, and work is normal, satisfies system test demand; the arrangement of the capacitor C1 and the capacitor C2 can filter differential mode interference signals; the inductor L is arranged, the magnetic flux directions of two coils of the inductor L are the same, when common-mode interference occurs in a circuit, the total inductance is rapidly increased after coupling, and great inductive reactance is presented to common-mode signals, so that the common-mode signals are not easy to pass through; the capacitor C3 and the capacitor C4 are arranged, the capacitor C3 and the capacitor C4 are connected across the output end, the midpoint of the capacitor is grounded, and common-mode interference can be effectively suppressed.

Description

Common mode inductor is with filtering common mode interference mechanism

Technical Field

The utility model belongs to the technical field of the common mode interference mechanism, especially, relate to a common mode inductor is with filtering common mode interference mechanism.

Background

Common mode inductor (Common mode Choke), also called Common mode Choke, is commonly used in a switching power supply of a computer to filter Common mode electromagnetic interference signals. In the board design, the common mode inductor also plays a role in EMI filtering, and is used for inhibiting electromagnetic waves generated by the high-speed signal line from radiating and emitting outwards.

Common mode interference and differential mode interference are one of the important factors affecting the normal operation of electronic products, and can have serious influence on the output of the products and the stability of surrounding products.

However, the existing common mode interference mechanism also has the problems that the ripple of the output signal of the product is obviously large (more than 20mV), the voltage is unstable, the work is abnormal, the system test requirement cannot be met, the differential mode interference signal cannot be filtered, and the effect of inhibiting the common mode interference is poor.

Therefore, it is necessary to invent a common mode interference filtering mechanism for a common mode inductor.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problem, the utility model provides a common mode interference filtering mechanism for common mode inductor to solve the problem that the existing common mode interference mechanism still has product output signal ripple obviously bigger (greater than 20mV), voltage is unstable, work is abnormal, can not satisfy system test requirements, can not filter differential mode interference signal, and restrain the common mode interference effect poor, including circuit board, PCB I, PCB II, filter circuit, inductance, electric capacity I and electric capacity II, PCB I and circuit board pass through inductance and electric capacity I and circuit board electric connection, this inductance and electric capacity I set up to parallel connection; PCB II passes through electric capacity II and circuit board electric connection, and this PCB II passes through filter circuit with PCB I and is connected.

The filter circuit comprises a capacitor C1, an inductor L, a capacitor C2, a capacitor C3 and a capacitor C4, wherein two ends of the capacitor C1 are connected with two input ends; the number of the inductors L is 2; and two ends of the capacitor C2 are connected with two output ends.

The capacitor C1 and the capacitor C2 adopt film capacitors; 2 inductors L are adopted, and the magnetic flux directions of two coils of the 2 inductors L are the same; the capacitor C3 and the capacitor C4 adopt capacitors for filtering common-mode interference.

The capacitor C3 and the capacitor C4 are connected in series and then connected in parallel with the capacitor C2, and the capacitor C3 and the capacitor C4 are connected with the ground.

The capacitance ranges of the capacitor C1 and the capacitor C2 are 0.01-0.47 muF; the capacitor C3 and the capacitor C4 are ceramic capacitors, and the capacitance range is 2200 pF-0.1 muF.

Compared with the prior art, the utility model discloses following beneficial effect has:

1. the utility model discloses filter circuit's setting, according to formula f 1/2/LC computational circuit's resonant frequency, in the test process, adjustment inductance, electric capacity make resonant frequency close or be close to the central frequency of interference frequency with the interference frequency of product, to the very high electromagnetic interference of frequency, can use three-terminal capacitance or punching electric capacity to filter, through adopting above-mentioned power filter circuit, the product output signal ripple is obviously less (about 20mV), voltage stability, normal operation, satisfy system test demand.

2. The utility model discloses electric capacity C1 and electric capacity C2's setting can the filtering differential mode interference signal.

3. The utility model discloses inductance L's setting, the magnetic flux direction of two coils of inductance L is the same, when common mode interference appears in the circuit, through the rapid increase of total inductance volume behind the coupling, presents very big inductive reactance to common mode signal, makes it be difficult for passing through.

4. The utility model discloses electric capacity C3 and electric capacity C4's setting, electric capacity C3 and electric capacity C4 cross-over are at the output to with the midpoint grounding of electric capacity, can restrain common mode interference effectively.

Drawings

Fig. 1 is a schematic structural diagram of the present invention.

Fig. 2 is a schematic diagram of the common mode choke of the present invention.

Fig. 3 is a schematic diagram of the filter circuit of the present invention.

In the figure:

1-circuit board, 2-PCB I, 3-PCB II, 4-filter circuit, 41-capacitor C1, 42-inductor L, 43-capacitor C2, 44-capacitor C3, 45-capacitor C4, 5-inductor, 6-capacitor I, 7-capacitor II.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.

As shown in figures 1 to 3.

The utility model provides a common mode interference filtering mechanism for common mode inductor, including circuit board 1, PCB I2, PCB II 3, filter circuit 4, inductance 5, electric capacity I6 and electric capacity II 7, PCB I2 and circuit board 1 are through inductance 5 and electric capacity I6 and circuit board 1 electric connection, and this inductance 5 and electric capacity I6 set up to parallel connection; PCB II 3 passes through electric capacity II 7 and circuit board 1 electric connection, and this PCB II 3 passes through filter circuit 4 with PCB I2 and is connected.

Two ends of the capacitor C141 are connected with the two input ends; two ends of the capacitor C243 are connected with two output ends, and the capacitor C141 and the capacitor C243 can filter differential mode interference signals.

2 inductors L42 are adopted, and the magnetic flux directions of two coils of the 2 inductors L42 are the same, so that when common-mode interference occurs in a circuit, the total inductance value is rapidly increased after coupling, and a large inductive reactance is presented to a common-mode signal, so that the common-mode signal is not easy to pass through.

The capacitor C344 and the capacitor C445 are connected in series and then connected in parallel with the capacitor C243, and the ground is connected between the capacitor C344 and the capacitor C445, so that common-mode interference can be effectively inhibited.

The capacitance ranges of the capacitor C141 and the capacitor C243 are 0.01-0.47 muF; the capacitor C344 and the capacitor C445 are ceramic capacitors, the capacitance range is 2200 pF-0.1 muF, the resonant frequency of the circuit can be calculated according to the formula F of 1/2L/LC, in the test process, the inductor and the capacitor are adjusted to enable the resonant frequency to be close to or close to the center frequency of the interference frequency of the product, and the three-terminal capacitor or the feedthrough capacitor can be used for filtering electromagnetic interference with very high frequency.

Utilize technical scheme, or technical personnel in the field are in the utility model discloses under technical scheme's the inspiration, design similar technical scheme, and reach above-mentioned technological effect, all fall into the utility model discloses a protection scope.

Claims

1. A common mode inductor is with filtering common mode interference mechanism which characterized in that: the circuit board comprises a circuit board (1), a PCB I (2), a PCB II (3), a filter circuit (4), an inductor (5), a capacitor I (6) and a capacitor II (7), wherein the PCB I (2) and the circuit board (1) are electrically connected with the circuit board (1) through the inductor (5) and the capacitor I (6), and the inductor (5) and the capacitor I (6) are arranged to be connected in parallel; PCB II (3) passes through electric capacity II (7) and circuit board (1) electric connection, and this PCB II (3) passes through filter circuit (4) with PCB I (2) and is connected.

2. The common mode inductor common mode interference filtering mechanism according to claim 1, wherein: the filter circuit (4) comprises a capacitor C1(41), an inductor L (42), a capacitor C2(43), a capacitor C3(44) and a capacitor C4(45), wherein two ends of the capacitor C1(41) are connected with two input ends; the number of the inductors L (42) is 2; and two ends of the capacitor C2(43) are connected with two output ends.

3. The common mode inductor common mode interference filtering mechanism according to claim 2, wherein: the capacitor C1(41) and the capacitor C2(43) adopt film capacitors; 2 inductors L (42) are adopted, and the magnetic flux directions of two coils of the 2 inductors L (42) are the same; the capacitor C3(44) and the capacitor C4(45) adopt capacitors for filtering common-mode interference.

4. The common mode inductor common mode interference filtering mechanism according to claim 2, wherein: the capacitor C3(44) and the capacitor C4(45) are connected in series and then connected in parallel with the capacitor C2(43), and the capacitor C3(44) and the capacitor C4(45) are connected with the ground.

5. The common mode inductor common mode interference filtering mechanism according to claim 2, wherein: the capacitance ranges of the capacitor C1(41) and the capacitor C2(43) are 0.01-0.47 muF; the capacitor C3(44) and the capacitor C4(45) are ceramic capacitors, and the capacitance range is 2200 pF-0.1 muF.