CN209948953U

CN209948953U - Filter

Info

Publication number: CN209948953U
Application number: CN201921178463.1U
Authority: CN
Inventors: 刘蓉; 何克勤
Original assignee: XI'AN PIESON ELECTRONIC TECH Co Ltd
Current assignee: XI'AN PIESON ELECTRONIC TECH Co Ltd
Priority date: 2019-07-25
Filing date: 2019-07-25
Publication date: 2020-01-14
Anticipated expiration: 2029-07-25

Abstract

The utility model discloses a filter, including common mode filter L1, first order LC low pass filter circuit and the second level LC low pass filter circuit that connects gradually, an input of common mode filter L1 is connected with diode D1's negative pole, and diode D1's positive pole is connected with power supply's positive pole, another input of common mode filter L1 is connected with power supply's negative pole, first order LC low pass filter circuit includes first differential mode filter inductance L2, polarity electric capacity C1 and polarity electric capacity C2, second level LC low pass filter circuit includes second differential mode filter inductance L3, polarity electric capacity C3 and polarity electric capacity C4. The utility model relates to a novelty, it is small, can two-way filtering electromagnetic conduction interference, to the electromagnetic interference that self equipment produced when providing clear power supply environment for equipment filtering, signal transmission is stable.

Description

Filter

Technical Field

The utility model belongs to the technical field of the wave filter, concretely relates to wave filter.

Background

In a severe electromagnetic interference environment, an electronic device must mount a filter on a power bus at the inlet of its power supply. The electromagnetic interference signal generated by the equipment (especially the equipment power supply) is blocked from being transmitted to the power bus to influence other equipment. The existing bidirectional power input filter has large filter inductance and capacitance, which causes the filter to be large in size, and in addition, the problems of unstable signal transmission and mutual interference among signals are also common problems of the filter, and a further improvement scheme is needed to be provided.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that not enough among the above-mentioned prior art is directed at, provide a wave filter, its novel in design is reasonable, and is small, can two-way filtering electromagnetic conduction interference, carries out the filtering to the electromagnetic interference that self equipment produced when providing clear power supply environment for equipment, and signal transmission is stable, convenient to popularize and use.

In order to solve the technical problem, the utility model discloses a technical scheme is: a filter, characterized by: the low-pass filter circuit comprises a common-mode filter L1, a first-stage LC low-pass filter circuit and a second-stage LC low-pass filter circuit which are connected in sequence, wherein one input end of a common-mode filter L1 is connected with the cathode of a diode D1, the anode of a diode D1 is connected with the anode of a power supply, the other input end of the common-mode filter L1 is connected with the cathode of the power supply, the first-stage LC low-pass filter circuit comprises a first differential-mode filter inductor L2, a polar capacitor C1 and a polar capacitor C2, one end of the first differential-mode filter inductor L2 is connected with one output end of the common-mode filter L1, the other end of the first differential-mode filter inductor L2 is connected with the anode of a polar capacitor C1, the cathode of a polar capacitor C1 is connected with the anode of a polar capacitor C2, the cathode of a polar capacitor C2 is connected with the other output end of the common-mode filter L1, the, The polarity capacitor C3 and the polarity capacitor C4, one end of the second differential mode filter inductor L3 is connected with the connection end of the first differential mode filter inductor L2 and the polarity capacitor C1, the other end of the second differential mode filter inductor L3 is divided into three paths, one path is connected with the anode of the secondary power supply of the equipment, the other path is grounded through the capacitor C5, and the third path is connected with the anode of the polarity capacitor C3; the negative electrode of the polar capacitor C3 is connected with the positive electrode of the polar capacitor C4, the negative electrode of the polar capacitor C4 is divided into three paths, one path is connected with the connecting end of the polar capacitor C2 and the common mode filter L1, the other path is grounded through the capacitor C6, and the third path is connected with the negative electrode of the secondary power supply of the equipment.

The filter is characterized in that: the common mode filter L1, the first-stage LC low-pass filter circuit and the second-stage LC low-pass filter circuit are integrated on a printed board, the printed board is arranged in a metal shell, the printed board is fixed in the metal shell through heat conducting glue, and the metal shell is grounded.

The filter is characterized in that: the common mode filter L1 is made by winding two windings in parallel.

The filter is characterized in that: the polar capacitor C1 is connected with a resistor R1 in parallel, and the polar capacitor C2 is connected with a resistor R2 in parallel.

The filter is characterized in that: the polar capacitor C3 is connected with a resistor R3 in parallel, and the polar capacitor C4 is connected with a resistor R4 in parallel.

Compared with the prior art, the utility model has the following advantage:

1. the utility model discloses an install between power supply and equipment secondary power, realize the various electromagnetic interference signal that the outside conduction of filtering comes, guarantee equipment has clear power supply and normal work, simultaneously, blocks again that the electromagnetic interference signal that equipment produced influences other equipment, convenient to popularize and use on conducting power supply's the power bus.

2. The utility model discloses a rationally arrange common mode filter L1, reduce the volume of wave filter to consolidate through the heat-conducting glue embedment, reliable stable, excellent in use effect.

3. The utility model has novel and reasonable design, the diode D1 is a protection device for preventing the polarity of the input voltage from being reversely connected, when the polarity of the voltage is reversely connected, the diode D1 cuts off the reverse bias, thereby blocking the reverse polarity voltage from entering the secondary power supply of the equipment through the filter and burning or damaging the instrument equipment; l1 is that the common mode filter presents a high resistance to common mode interference signals and blocks them, the first differential mode filter inductor L2 and the second differential mode filter inductor L3 only block differential mode interference signals, and form a two-stage LC low-pass filter circuit together with the polar capacitor C1, the polar capacitor C2, the polar capacitor C3 and the polar capacitor C4, so as to realize the two-way filtering of differential mode high-frequency interference signals, the capacitors C5 and C6 are all connected to the metal shell ground, so as to provide a low-resistance bleed-off channel for common mode interference signals, and combine with the common mode filter L1 to realize the filtering of common mode interference signals, and the resistor R1, the resistor R2, the resistor R3 and the resistor R4 are used as the bleed-off resistors of large capacitors in the filter and have a damping effect, so as to facilitate popularization and use.

To sum up, the utility model relates to a novelty is reasonable, and is small, can two-way filtering electromagnetic conduction interference, carries out the filtering to the electromagnetic interference that self equipment produced when providing clear power supply environment for equipment, and signal transmission is stable, convenient to popularize and use.

The technical solution of the present invention is further described in detail by the accompanying drawings and examples.

Drawings

Fig. 1 is a usage state diagram of the present invention.

Fig. 2 is a schematic circuit diagram of the present invention.

Description of reference numerals:

1-a metal housing; 2-equipment secondary power supply; 3-apparatus equipment.

Detailed Description

As shown in fig. 1 and fig. 2, the present invention includes a common mode filter L1, a first stage LC low pass filter circuit and a second stage LC low pass filter circuit connected in sequence, one input terminal of the common mode filter L1 is connected to the cathode of a diode D1, the anode of the diode D1 is connected to the anode of a power supply, the other input terminal of the common mode filter L1 is connected to the cathode of the power supply, the first stage LC low pass filter circuit includes a first differential mode filter inductor L2, a polarity capacitor C1 and a polarity capacitor C2, one end of the first differential mode filter inductor L2 is connected to one output terminal of the common mode filter L1, the other end of the first differential mode filter inductor L2 is connected to the anode of a polarity capacitor C1, the cathode of the polarity capacitor C1 is connected to the anode of a polarity capacitor C2, the cathode of the polarity capacitor C2 is connected to the other output terminal of the common mode filter L1, the second-stage LC low-pass filter circuit comprises a second differential mode filter inductor L3, a polar capacitor C3 and a polar capacitor C4, one end of the second differential mode filter inductor L3 is connected with the connecting end of the first differential mode filter inductor L2 and the polar capacitor C1, the other end of the second differential mode filter inductor L3 is divided into three paths, one path is connected with the anode of the equipment secondary power supply 2, the other path is grounded through a capacitor C5, and the third path is connected with the anode of the polar capacitor C3; the negative electrode of the polar capacitor C3 is connected with the positive electrode of the polar capacitor C4, the negative electrode of the polar capacitor C4 is divided into three paths, one path is connected with the connection end of the polar capacitor C2 and the common mode filter L1, the other path is grounded through the capacitor C6, and the third path is connected with the negative electrode of the equipment secondary power supply 2.

It should be noted that, the filter is installed between the power supply and the secondary power supply 2 of the device, so as to filter out various electromagnetic interference signals conducted from the outside, ensure the instrument 3 to have clean power supply and work normally, and simultaneously prevent the electromagnetic interference signals generated by the instrument 3 from being conducted to the power bus of the power supply to affect other devices; the common mode filter L1 is reasonably arranged, so that the size of the filter is reduced, and the filter is reinforced by heat-conducting glue in a filling and sealing manner, and is reliable and stable and good in using effect; the diode D1 is a protection device for preventing the polarity of the input voltage from being connected reversely, when the polarity of the voltage is connected reversely, the diode D1 cuts off the reverse bias, thereby blocking the reverse polarity voltage from entering the secondary power supply of the equipment through the filter and burning or damaging the equipment; l1 is that the common mode filter presents a high resistance to common mode interference signals and blocks them, the first differential mode filter inductor L2 and the second differential mode filter inductor L3 only block differential mode interference signals, and form a two-stage LC low-pass filter circuit together with the polar capacitor C1, the polar capacitor C2, the polar capacitor C3 and the polar capacitor C4 to realize bidirectional filtering of differential mode high-frequency interference signals, the capacitors C5 and C6 are all connected to the metal shell in a grounded manner and used for providing a low-resistance bleed-off channel for common mode interference signals, and the common mode filter L1 is combined to realize filtering of common mode interference signals.

In this embodiment, the common mode filter L1, the first-stage LC low-pass filter circuit, and the second-stage LC low-pass filter circuit are all integrated on a printed board, the printed board is disposed in the metal casing 1, the printed board is fixed in the metal casing 1 by a heat-conducting adhesive, and the metal casing 1 is grounded.

In this embodiment, the common mode filter L1 is made by winding two windings in parallel.

It should be noted that the printed board is fixed in the metal casing 1 by a heat conducting adhesive to reduce the volume, the metal casing 1 is grounded, and the capacitors C5 and C6 must be connected to the metal casing 1 as short as possible.

In this embodiment, the polar capacitor C1 is connected in parallel with the resistor R1, and the polar capacitor C2 is connected in parallel with the resistor R2.

In this embodiment, the polar capacitor C3 is connected in parallel with the resistor R3, and the polar capacitor C4 is connected in parallel with the resistor R4.

The resistor R1 has a damping function as a bleed-off resistor of the polar capacitor C1, the resistor R2 has a damping function as a bleed-off resistor of the polar capacitor C2, the resistor R3 has a damping function as a bleed-off resistor of the polar capacitor C3, and the resistor R4 has a damping function as a bleed-off resistor of the polar capacitor C4.

In practical use, the common mode filter L1 adopts a common mode filter of type 1SMB562545-101, the diode D1 adopts a diode of type BYW29G-200, the first differential mode filter inductor L2 and the second differential mode filter inductor L3 both adopt differential mode filter inductors of type PB4532-101, the capacitance value of the polar capacitor C1, the capacitance value of the polar capacitor C2, the capacitance value of the polar capacitor C3 and the capacitance value of the polar capacitor C4 are both 10 μ F, the capacitance value of the capacitor C5 and the capacitance value of the capacitor C6 are both 0.1 μ F, and the resistance value of the resistor R1, the resistance value of the resistor R2, the resistance value of the resistor R3 and the resistance value of the resistor R4 are all 910k Ω.

When the utility model is used, the common mode filter L1 presents high resistance to the common mode interference signal to block it, the first differential mode filter inductor L2 and the second differential mode filter inductor L3 only block the differential mode interference signal, the polar capacitor C1, the polar capacitor C2, the polar capacitor C3 and the polar capacitor C4 form a two-stage LC low-pass filter circuit together to realize bidirectional filtering of differential mode high-frequency interference signals, the capacitor C5 and the capacitor C6 are all connected with the metal shell in a grounding way, the common-mode filter is used for providing a low-resistance leakage channel for common-mode interference signals, the common-mode filter is combined with the L1 to filter the common-mode interference signals, the resistor R1, the resistor R2, the resistor R3 and the resistor R4 are used as leakage resistors of large capacitors in the filter and have a damping effect, clean power supply environment is provided for equipment, meanwhile, electromagnetic interference generated by the equipment is filtered, and signal transmission is stable.

The above, only be the utility model discloses a preferred embodiment, it is not right the utility model discloses do any restriction, all according to the utility model discloses the technical entity all still belongs to any simple modification, change and the equivalent structure change of doing above embodiment the utility model discloses technical scheme's within the scope of protection.

Claims

1. A filter, characterized by: the low-pass filter circuit comprises a common-mode filter L1, a first-stage LC low-pass filter circuit and a second-stage LC low-pass filter circuit which are connected in sequence, wherein one input end of a common-mode filter L1 is connected with the cathode of a diode D1, the anode of a diode D1 is connected with the anode of a power supply, the other input end of the common-mode filter L1 is connected with the cathode of the power supply, the first-stage LC low-pass filter circuit comprises a first differential-mode filter inductor L2, a polar capacitor C1 and a polar capacitor C2, one end of the first differential-mode filter inductor L2 is connected with one output end of the common-mode filter L1, the other end of the first differential-mode filter inductor L2 is connected with the anode of a polar capacitor C1, the cathode of a polar capacitor C1 is connected with the anode of a polar capacitor C2, the cathode of a polar capacitor C2 is connected with the other output end of the common-mode filter L1, the, The polarity capacitor C3 and the polarity capacitor C4, one end of the second differential mode filter inductor L3 is connected with the connection end of the first differential mode filter inductor L2 and the polarity capacitor C1, the other end of the second differential mode filter inductor L3 is divided into three paths, one path is connected with the anode of the equipment secondary power supply (2), the other path is grounded through the capacitor C5, and the third path is connected with the anode of the polarity capacitor C3; the negative electrode of the polar capacitor C3 is connected with the positive electrode of the polar capacitor C4, the negative electrode of the polar capacitor C4 is divided into three paths, one path is connected with the connecting end of the polar capacitor C2 and the common mode filter L1, the other path is grounded through the capacitor C6, and the third path is connected with the negative electrode of the equipment secondary power supply (2).

2. A filter according to claim 1, characterized in that: the common mode filter L1, the first-stage LC low-pass filter circuit and the second-stage LC low-pass filter circuit are integrated on a printed board, the printed board is arranged in the metal shell (1), the printed board is fixed in the metal shell (1) through heat conducting glue, and the metal shell (1) is grounded.

3. A filter according to claim 1, characterized in that: the common mode filter L1 is made by winding two windings in parallel.

4. A filter according to claim 1, characterized in that: the polar capacitor C1 is connected with a resistor R1 in parallel, and the polar capacitor C2 is connected with a resistor R2 in parallel.

5. A filter according to claim 1, characterized in that: the polar capacitor C3 is connected with a resistor R3 in parallel, and the polar capacitor C4 is connected with a resistor R4 in parallel.