CN205945670U - High -order common mode filter circuit and PCB circuit board - Google Patents
High -order common mode filter circuit and PCB circuit board Download PDFInfo
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- CN205945670U CN205945670U CN201620780612.1U CN201620780612U CN205945670U CN 205945670 U CN205945670 U CN 205945670U CN 201620780612 U CN201620780612 U CN 201620780612U CN 205945670 U CN205945670 U CN 205945670U
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Abstract
The utility model relates to a filter circuit field provides a high -order common mode filter circuit and PCB circuit board, and the conduction and the electromagnetic radiation that solve high frequency, high strength disturb the problem. High -order common mode filter circuit includes positive input terminal, negative input end, first electric capacity, second electric capacity, a T type filter circuit, the 2nd T type filter circuit, a RC filter circuit, the 2nd RC filter circuit, forward transportation output and negative output end, wherein: positive input terminal, a T type filter circuit, a RC filter circuit, forward transportation output are established ties, and simultaneously, positive input terminal still is connected with the one end of first electric capacity, and the negative output end still is connected with the one end of second electric capacity, negative input end, the 2nd T type filter circuit, the 2nd RC filter circuit, negative output end are established ties, and simultaneously, the negative input end still is connected with the other end of first electric capacity, and the negative output end still is connected with the other end of second electric capacity. The utility model is suitable for a high frequency filter.
Description
Technical field
This utility model is related to filter circuit, more particularly, to high-order common mode filtering circuit and PCB.
Background technology
With the continuous improvement of scientific and technical continuous development and living standards of the people, increasing intelligent artifact is come into
Our life, intelligent artifact largely relies on the development of sensor technology, but sensor signal is faint and deposits
In the interference of the series such as noise, conduction, electromagnetic radiation, and these interference are usually presented in common mode disturbances.However, passing
The filter circuit of system is simply filtered it is impossible to eliminate common mode disturbances to positive signal.
During collecting sensor signal, signal is transmitted filtering most doing in the way of Differential Input
Disturb, state compulsion standard reaches 10V to such non-automatic weighing instrument, the intensity of Conduction Interference, and the intensity of electromagnetic interference reaches
10V/M.More than its Radix Achyranthis Bidentatae compared to the sensor signal intensity of Differential Input, interfering frequency between 150KHZ-2GHZ, face
To such interference, rely solely on Differential Input can not effective filtering interfering, a now stable common mode filtering electricity
The design on road serves the effect of key in signal transmission system.
Utility model content
The technical problems to be solved in the utility model is：A kind of high-order common mode filtering circuit and PCB are provided, solve
High frequency, the conduction of high intensity and electromagnetic interference problem.
For solving the above problems, the technical solution adopted in the utility model is：High-order common mode filtering circuit and PCB circuit
Plate, including positive input terminal, negative input end, the first electric capacity, the second electric capacity, the first T-shaped filter circuit, the second T-shaped filter circuit,
One RC filter circuit, the 2nd RC filter circuit, positive output end and negative output terminal；Wherein：Positive input terminal, the first T-shaped filtered electrical
Road, a RC filter circuit, positive output end series connection, meanwhile, positive input terminal is also connected with one end of the first electric capacity, and positive output end is also
It is connected with one end of the second electric capacity；Negative input end, the second T-shaped filter circuit, the 2nd RC filter circuit, negative output terminal series connection, with
When, negative input end is also connected with the other end of the first electric capacity, and negative output terminal is also connected with the other end of the second electric capacity.
Further, described first T-shaped filter circuit includes the first inductance, the second inductance, the 3rd electric capacity；Described 2nd T
Type filter circuit includes the 3rd inductance, the 4th inductance, the 4th electric capacity；First RC filter circuit bag first resistor and the 5th electric capacity；
2nd RC filter circuit bag second resistance and the 6th electric capacity；
Wherein：One end of first inductance is connected with positive input terminal；One end of the other end of the first inductance and the second inductance,
One end of three electric capacity connects；The other end ground connection of the 3rd electric capacity；The other end of the second inductance is connected with one end of first resistor；The
The other end of one resistance is connected with one end of the 5th electric capacity, positive output end；The other end ground connection of the 5th electric capacity；The one of 3rd inductance
End is connected with negative input end；The other end of the 3rd inductance is connected with one end of the 4th inductance, one end of the 4th electric capacity；4th electric capacity
The other end ground connection；The other end of the 4th inductance is connected with one end of second resistance；The other end of second resistance and the 6th electric capacity
One end, negative output terminal connect；The other end ground connection of the 6th electric capacity.
Further, the parameter of each components and parts in the first T-shaped filter circuit and each components and parts in the second T-shaped filter circuit
Parameter consistent, the parameter of each components and parts in the parameter of each components and parts in a RC filter circuit and the 2nd RC filter circuit
Unanimously.
PCB, is furnished with above-mentioned high-order common mode filtering circuit in PCB, the first T-shaped filter circuit,
Position in PCB for the one RC filter circuit respectively with the second T-shaped filter circuit, the 2nd RC filter circuit in PCB circuit
Positional symmetry on plate.
The beneficial effects of the utility model are：, problem of high cost complicated compared to the design of conventional active wave filter, this reality
With the new two-stage quadravalence filter in series using a T-shaped filter circuit being made up of LCL and a RC low-pass filter circuit
Ripple device forms, then composes in parallel common mode filtering circuit by two same two-stage fourth order low-pass wave filter, thus simultaneously to positive and negative
The signal of pole is filtered processing, and has the advantages that structure is simple, low cost, reliability are high, highly attenuating ratio arranges.
Brief description
Fig. 1 is the circuit diagram of embodiment；
Fig. 2 is the amplitude-versus-frequency curve figure of embodiment.
In figure is numbered：L1-L4 is first to fourth inductance, and C1-C6 is the first to the 6th electric capacity, and R1-R2 is first to the
Two resistance, Uin is input, and Uout is outfan.
Specific embodiment
By the following examples this utility model is described further.
The system of Today, most belt sensor device small-signal input, needs by state compulsion standard, this standard is to height
Keep pouring in dodar and reach 10V/M (mainly more than 150KHZ operating frequency) considerably beyond biography to 10V and high frequency electromagnetic radiation interference
The differential signal of sensor output.For this particular/special requirement, the present embodiment common mode filtering circuit is to 150KHZ-2GHZ frequency band
High frequency common mode interference filter depth is more than 75dB.
Embodiment common mode filtering circuit is composed in parallel by two groups of two-stage fourth order low-pass wave filter, and two groups of two-stages four in parallel
In rank low pass filter, the parameter of components and parts is consistent, it is to avoid parameter differences cause the difference of actual filter effect.Each two-stage four
Rank low pass filter is in series using a T-shaped filter circuit being made up of LCL and a RC low-pass filter circuit.
Specifically, as shown in figure 1, embodiment common mode filtering circuit include positive input terminal, negative input end, the first electric capacity C1,
Second electric capacity C2, the first T-shaped filter circuit, the second T-shaped filter circuit, a RC filter circuit, the 2nd RC filter circuit, just defeated
Go out end and negative output terminal；Wherein, described first T-shaped filter circuit includes the first inductance L1, the second inductance L2, the 3rd electric capacity
C3；Described second T-shaped filter circuit includes the 3rd inductance L3, the 4th inductance L4, the 4th electric capacity C4；First RC filter circuit bag
One resistance R1 and the 5th electric capacity C5；2nd RC filter circuit bag second resistance R2 and the 6th electric capacity C6.
The connected mode of each components and parts is：One end of first inductance L1 is connected with positive input terminal；First inductance L1's is another
End is connected with one end of the second inductance L2, one end of the 3rd electric capacity C3；The other end ground connection of the 3rd electric capacity C3；Second inductance L2's
The other end is connected with one end of first resistor R1；One end of the other end of first resistor R1 and the 5th electric capacity C5, positive output end are even
Connect；The other end ground connection of the 5th electric capacity C5；One end of 3rd inductance L3 is connected with negative input end；The other end of the 3rd inductance L3 with
One end of 4th inductance L4, one end of the 4th electric capacity C4 connect；The other end ground connection of the 4th electric capacity C4；4th inductance L4's is another
End is connected with one end of second resistance R2；The other end of second resistance R2 is connected with one end of the 6th electric capacity C6, negative output terminal；The
The other end ground connection of six electric capacity C6.
The cut-off frequency of embodiment common mode filtering circuit is collectively formed by T-shaped filter circuit and RC low-pass filter circuit.T-shaped
The 3dB of filter circuit by frequency is：The 3dB of RC low-pass filter circuit by frequency is：
Above-mentioned, the value of first to fourth inductance L1-L4 is 2nH, and C1 value is 100pF, the value of the second to the 6th electric capacity C2-C6
For 0.01uF, the value of the first to second resistance R1-R2 is 1k Ω.
During circuit work, common-mode noise is filtered by two groups of T-shaped filter circuits and RC low-pass filter circuit.Input signal is passed through
First electric capacity C1 two ends input, positive signal first passes through the first inductance L1, (negative pole is then the 3rd electricity for the second inductance L2, electric capacity C3
Sense L3, the 4th inductance L4, the 4th electric capacity C4) the three stages T-shaped filter circuit that forms, the transfer function H (s) of T-shaped filter circuit=
1；The RC low-pass filtering forming through first resistor R1, the 5th electric capacity C5 (negative pole is then second resistance R2, the 6th electric capacity C6) again,
The transmission function of low pass filterFinally exported by low temperature the second electric capacity C2 two ends.
The amplitude-versus-frequency curve of embodiment as shown in Figure 2 it can be seen that 10dB decay by frequency be 1KHZ,
150KHZ reaches 75dB by the decay of frequency.
Further, since PCB has parasitic capacitance and stray inductance in itself, the electricity in common mode filtering circuit can be affected
Hold and inductance value, thus the performance of PCB that impact is made, therefore, in the common mode filtering circuit making sheet by embodiment
When, the filtering part of positive and negative polarities should be designed to symmetrical structure, i.e. the first T-shaped filter circuit, a RC filter circuit
The position in PCB respectively with the second T-shaped filter circuit, position pair in PCB for the 2nd RC filter circuit
Claim, symmetrical mode can be symmetrical above and below, so can effectively reduce parasitic capacitance and stray inductance it is ensured that the filter of positive and negative polarities
The Performance And Reliability of ripple part.
It is pointed out that some principles of the present utility model that simply explain through diagrams described above, due to identical skill
It is easy to for the those of ordinary skill in art field carry out some modifications on this basis and change.Therefore, this specification
Be not intended to by this utility model be confined to shown in and described concrete structure and the scope of application in, therefore every be possible to sharp
Corresponding modification and equivalent, belong to the apllied the scope of the claims of this utility model.
Claims (4)
1. high-order common mode filtering circuit it is characterised in that include positive input terminal, negative input end, the first electric capacity, the second electric capacity, the
One T-shaped filter circuit, the second T-shaped filter circuit, a RC filter circuit, the 2nd RC filter circuit, positive output end and negative defeated
Go out end；Wherein：Positive input terminal, the first T-shaped filter circuit, a RC filter circuit, positive output end series connection, meanwhile, positive input terminal
Also it is connected with one end of the first electric capacity, positive output end is also connected with one end of the second electric capacity；Negative input end, the second T-shaped filtered electrical
Road, the 2nd RC filter circuit, negative output terminal series connection, meanwhile, negative input end is also connected with the other end of the first electric capacity, negative output terminal
Also it is connected with the other end of the second electric capacity.
2. high-order common mode filtering circuit as claimed in claim 1 is it is characterised in that described first T-shaped filter circuit includes
One inductance, the second inductance, the 3rd electric capacity；Described second T-shaped filter circuit includes the 3rd inductance, the 4th inductance, the 4th electric capacity；The
One RC filter circuit bag first resistor and the 5th electric capacity；2nd RC filter circuit bag second resistance and the 6th electric capacity；
Wherein：One end of first inductance is connected with positive input terminal；One end of the other end of the first inductance and the second inductance, the 3rd electricity
The one end holding connects；The other end ground connection of the 3rd electric capacity；The other end of the second inductance is connected with one end of first resistor；First electricity
The other end of resistance is connected with one end of the 5th electric capacity, positive output end；The other end ground connection of the 5th electric capacity；One end of 3rd inductance with
Negative input end connects；The other end of the 3rd inductance is connected with one end of the 4th inductance, one end of the 4th electric capacity；4th electric capacity another
One end is grounded；The other end of the 4th inductance is connected with one end of second resistance；The other end of second resistance and the one of the 6th electric capacity
End, negative output terminal connect；The other end ground connection of the 6th electric capacity.
3. high-order common mode filtering circuit as claimed in claim 2 it is characterised in that in the first T-shaped filter circuit each unit device
The parameter of part is consistent with the parameter of each components and parts in the second T-shaped filter circuit, the ginseng of each components and parts in a RC filter circuit
Number is consistent with the parameter of each components and parts in the 2nd RC filter circuit.
4.PCB circuit board is it is characterised in that be furnished with high-order common mode filtering electricity as claimed in claim 3 in PCB
Road, the first T-shaped filter circuit, position in PCB for the RC filter circuit respectively with the second T-shaped filter circuit,
Positional symmetry in PCB for the two RC filter circuits.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620780612.1U CN205945670U (en) | 2016-07-22 | 2016-07-22 | High -order common mode filter circuit and PCB circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620780612.1U CN205945670U (en) | 2016-07-22 | 2016-07-22 | High -order common mode filter circuit and PCB circuit board |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205945670U true CN205945670U (en) | 2017-02-08 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620780612.1U Active CN205945670U (en) | 2016-07-22 | 2016-07-22 | High -order common mode filter circuit and PCB circuit board |
Country Status (1)
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| CN (1) | CN205945670U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109756202A (en) * | 2019-01-30 | 2019-05-14 | 华勤通讯技术有限公司 | A kind of motor drive circuit and terminal |
-
2016
- 2016-07-22 CN CN201620780612.1U patent/CN205945670U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109756202A (en) * | 2019-01-30 | 2019-05-14 | 华勤通讯技术有限公司 | A kind of motor drive circuit and terminal |
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