CN218734226U

CN218734226U - High-rejection low-pass filter

Info

Publication number: CN218734226U
Application number: CN202223003272.6U
Authority: CN
Inventors: 盖广洪; 颜逊
Original assignee: Suzhou Hangkai Microelectronics Technology Co ltd
Current assignee: Suzhou Hangkai Microelectronics Technology Co ltd
Priority date: 2022-11-11
Filing date: 2022-11-11
Publication date: 2023-03-24
Anticipated expiration: 2032-11-11

Abstract

The utility model discloses a high suppression low pass filter relates to the filtering field, and this high suppression low pass filter includes: the LC filtering module is used for filtering the input signal; the LC filter module is formed by connecting a plurality of filter circuits in series, and the adjacent filter circuits are installed in a positive and negative alternate mode; the filter circuit includes first inductance, first electric capacity, second electric capacity, third electric capacity, compares with prior art, the beneficial effects of the utility model are that: the utility model discloses adjacent positive and negative alternate installation of filter circuit for regional positive and negative alternate installation about adjacent hollow coil is installed in LC wave filter, makes the mutual inductance of filter circuit reduce, through the inductance value of adjustment hollow inductance, reaches to increase and vibrates transmission characteristic, increases inductance Q value, promotes the purpose of wave filter index, has compromise wave filter performance and volume, has compact structure, high suppression, high steepness, low-loss advantage.

Description

High-rejection low-pass filter

Technical Field

The utility model relates to a filtering field specifically is a high suppression low pass filter.

Background

The filter is a filter circuit composed of devices such as a capacitor and an inductor. The filter can effectively filter the frequency point of the specific frequency in the power line or the frequencies except the frequency point to obtain a power signal of the specific frequency or eliminate the power signal of the specific frequency.

The existing filter is often provided with a plurality of filter circuits for enhancing the filtering effect, so that the filtering effect is enhanced, mutual inductance is generated between inductors among the plurality of filter circuits, and the existing filter is not beneficial to obtaining stable power signals and needs to be improved.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a high suppression low pass filter to solve the problem that proposes among the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme:

a high rejection low pass filter comprising:

the LC filtering module is used for filtering the input signal;

the LC filter module is formed by connecting a plurality of filter circuits in series, and the adjacent filter circuits are installed in a positive and negative alternate mode;

the filter circuit comprises a first inductor, a first capacitor, a second capacitor and a third capacitor, wherein one end of the first inductor is connected with one end of the first capacitor and one end of the third capacitor, the other end of the first inductor is connected with the other end of the third capacitor and one end of the second capacitor, and the other end of the second capacitor is grounded; the inductor is an air-core coil, and adjacent filter circuits share one capacitor.

As a further aspect of the present invention: the high-rejection low-pass filter also comprises an effect amplification module, and the effect amplification module is used for amplifying the filtering effect of the LC filtering module;

the effect amplification module comprises a first resistor and a first triode, one end of the first resistor is connected with an input signal, the other end of the first resistor is connected with a collector electrode of the first triode, a base electrode of the first triode is connected with the LC filtering module, and an emitting electrode of the first triode is connected with the abnormity alarm module.

As a further aspect of the present invention: the high-rejection low-pass filter also comprises an abnormal alarm module, and the abnormal alarm module is used for alarming and ringing when the LC filtering module fails;

the abnormity alarm module comprises a second resistor, a third resistor, a fourth resistor, a first diode, an amplifier and a loudspeaker, one end of the fourth resistor is connected with one end of the second resistor, the effect amplification module, one end of the third resistor is connected with the other end of the second resistor, the inverting terminal of the amplifier is connected with the inverting terminal of the amplifier, the other end of the third resistor is grounded, the other end of the fourth resistor is connected with the cathode of the first diode, the inverting terminal of the amplifier, the anode of the first diode is grounded, one end of the loudspeaker is connected with the output end of the amplifier, and the other end of the loudspeaker is grounded.

As a further aspect of the present invention: the adjacent air-core coils are installed in a positive and negative alternate mode.

As a further aspect of the present invention: the hollow-core inductor is wound by adopting a pure copper enameled wire with the diameter of 1.6-2.1 mm, and the length of depainting at two ends of the hollow-core coil is not longer than 3mm.

Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses adjacent positive and negative alternate installation of filter circuit for regional positive and negative alternate installation about adjacent hollow coil is installed in LC wave filter, makes the mutual inductance of filter circuit reduce, through the inductance value of adjustment hollow inductance, reaches to increase and vibrates transmission characteristic, increases inductance Q value, promotes the purpose of wave filter index, has compromise wave filter performance and volume, has compact structure, high suppression, high steepness, low-loss advantage.

Drawings

Fig. 1 is a schematic diagram of a high rejection low pass filter.

Fig. 2 is a circuit diagram of a high rejection low pass filter.

Figure 3 is a schematic diagram of the air core coil being installed with opposite sides.

Fig. 4 is a schematic diagram of an amplifier input waveform.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, rather than all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without creative work belong to the protection scope of the present invention based on the embodiments of the present invention.

Referring to fig. 1 and fig. 2, a high rejection low pass filter includes:

the LC filtering module is used for filtering the input signal;

the filter circuit comprises a first inductor L1, a first capacitor C1, a second capacitor C2 and a third capacitor C3, wherein one end of the first inductor L1 is connected with one end of the first capacitor C1 and one end of the third capacitor C3, the other end of the first inductor L1 is connected with the other end of the third capacitor C3 and one end of the second capacitor C2, and the other end of the second capacitor C2 is grounded; the inductor is an air-core coil, and adjacent filter circuits share one capacitor (such as a second capacitor C2, a fifth capacitor C5, an eighth capacitor C8, an eleventh capacitor C11, and a fourteenth capacitor C14 shown in fig. 2).

In a specific embodiment: referring to fig. 2, the lc filter module includes a PCB substrate, a chip capacitor, and an air-core inductor, and the air-core inductor and the capacitor are fixed on the PCB substrate by soldering. The LC filter module comprises 13 chip capacitors and 6 wire-wound hollow inductors, the 6 filter circuits are formed, the hollow inductors are wound by pure copper enameled wires with the diameter of 1.6-2.1 mm, and the depainting lengths of the two ends of each hollow coil are not longer than 3mm. The left area and the right area of the hollow coil are installed in the LC filter in a positive and negative alternate mode, so that the mutual inductance of a filter circuit is reduced, and the aims of increasing the oscillation transmission characteristic, increasing the Q value of the inductor and improving the index of the filter are fulfilled by adjusting the inductance value of the hollow inductor. The filter has the advantages of compact structure, high suppression, high gradient and low loss.

In this embodiment: referring to fig. 2, the high-rejection low-pass filter further includes an effect amplification module, and the effect amplification module is configured to amplify a filtering effect of the LC filtering module;

the effect amplification module comprises a first resistor R1 and a first triode V1, wherein one end of the first resistor R1 is connected with an input signal VIN, the other end of the first resistor R1 is connected with a collector electrode of the first triode V1, a base electrode of the first triode V1 is connected with the LC filtering module, and an emitting electrode of the first triode V1 is connected with the abnormity alarm module.

The filtering effect is amplified through a first amplifier V1; therefore, when the LC filter module is provided with fewer filter circuits (for saving devices) and cannot filter out a large input signal VIN, the LC filter module is processed to obtain a smaller input signal VIN, and then the filter effect is amplified by the effect amplification module.

In this embodiment: referring to fig. 2 and 4, the high-rejection low-pass filter further includes an abnormal alarm module, and the abnormal alarm module is used for alarming and sounding when the LC filter module fails;

the abnormity warning module comprises a second resistor R2, a third resistor R3, a fourth resistor R4, a first diode D1, an amplifier U1 and a loudspeaker SPEAKER, wherein one end of the second resistor R2 is connected with one end of the fourth resistor R4, the effect amplification module, the other end of the second resistor R2 is connected with one end of the third resistor R3 and the inverting end of the amplifier U1, the other end of the third resistor R3 is grounded, the other end of the fourth resistor R4 is connected with the negative electrode of the first diode D1 and the inverting end of the amplifier U1, the positive electrode of the first diode D1 is grounded, the output end of the amplifier U1 is connected with one end of the loudspeaker SPEAKER, and the other end of the loudspeaker SPEAKER is grounded.

When the LC filtering module works normally, the output signal VOUT1 is a stable signal and has no fluctuation; the output signal VOUT2 after effect amplification should also be a steady signal, and there is no fluctuation, at this time, the voltage on the third resistor R3 will only be larger or smaller than the voltage on the first diode D1 (zener diode), so that the amplifier U1 outputs a high level or a low level, and the SPEAKER operates without outputting a frequency signal; when the LC filtering module works abnormally, the output signal VOUT1 is a fluctuation signal; the output signal VOUT2 after effect amplification is also a fluctuation signal, and at this time, the voltage across the third resistor R3 fluctuates (a fluctuation voltage signal in fig. 4), the voltage across the first diode D1 (a voltage regulator diode) is constant (a constant voltage signal in fig. 4), so that the voltage at the inverting terminal of the amplifier U1 fluctuates, the voltage at the non-inverting terminal does not change, and the output frequency signal causes the SPEAKER to operate and alarm.

In this embodiment: referring to fig. 2 and 3, adjacent air coils are alternately installed in opposite directions.

And the adjacent filter circuits are installed in a positive and negative alternate mode, so that the adjacent air-core coils are installed in the left and right areas in the LC filter in a positive and negative alternate mode, and the mutual inductance of the filter circuits is reduced. The mutual inductance is reduced by reversing the current flow of adjacent air coils in the figure.

In this embodiment: referring to fig. 2 and 3, the air-core inductor is wound by using a pure copper enameled wire with a diameter of 1.6 mm-2.1 mm, and the length of the depainting at two ends of the air-core coil is not longer than 3mm.

The utility model discloses a theory of operation is: an input signal VIN is input, and is filtered by an LC filtering module formed by a plurality of filtering circuits, and a stable output signal VOUT1 is output; when the input signal VIN is too large, the LC filtering module cannot process the input signal VIN, the input signal VIN is processed firstly, the processed output signal VOUT1 is output to the LC filtering module to be processed, and the output signal VOUT2 is obtained by amplifying the output signal through a first triode; when the LC filtering module is normally used, a stable output signal VOUT2 is output; when the LC filtering module is abnormally used (faults or input signals are too large and cannot be processed), the output signal VOUT2 fluctuates, and at the moment, the abnormal alarm module drives the loudspeaker to work to sound for alarming, so that a user is timely reminded.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A high rejection low pass filter, characterized by:

the high rejection low pass filter includes:

the LC filtering module is used for filtering the input signal;

2. The high-rejection low-pass filter according to claim 1, further comprising an effect amplification module for amplifying the filtering effect of the LC filtering module;

the effect amplification module comprises a first resistor and a first triode, wherein one end of the first resistor is connected with an input signal, the other end of the first resistor is connected with a collector of the first triode, a base of the first triode is connected with the LC filtering module, and an emitting electrode of the first triode is connected with the abnormity alarm module.

3. The high-rejection low-pass filter according to claim 1 or 2, further comprising an abnormality alarm module for alarming and ringing when the LC filter module fails;

4. A high rejection low pass filter according to claim 1 wherein adjacent air core coils are mounted face to face.

5. The high-rejection low-pass filter according to claim 4, wherein the air-core inductor is wound by pure copper enameled wires with the diameter of 1.6mm to 2.1mm, and the length of the depainting at two ends of the air-core coil is not longer than 3mm.