CN1811487A - Preamplification and filtering circuit for precision isolated amplifier - Google Patents
Preamplification and filtering circuit for precision isolated amplifier Download PDFInfo
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- CN1811487A CN1811487A CN 200610031312 CN200610031312A CN1811487A CN 1811487 A CN1811487 A CN 1811487A CN 200610031312 CN200610031312 CN 200610031312 CN 200610031312 A CN200610031312 A CN 200610031312A CN 1811487 A CN1811487 A CN 1811487A
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- filtering circuit
- circuit
- amplification
- operational amplifier
- resistance
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Abstract
The present invention discloses a precision isolated amplifier preamplification and filter circuit. It includes input protection circuit, buffer circuit and amplification and filter circuit. The described input protection circuit, buffer circuit, amplification and filter circuit are successively connected, the amplification and filter circuit can be three-stage amplification and filter circuit optimally, and the circuit structures of all the stages are identical. Besides, it uses low-temperature drift amplifier to raise accuracy, and designs passive RC filter so as to reduce noise.
Description
Technical field
The present invention relates to a kind of amplification and filtering circuit, especially relate to preposition amplification of a kind of precision isolated amplifier and filtering circuit.
Background technology
In the electrical method exploration instrument for geology, generally at its preposition gain enlarging function that is provided with, but the shelves difference is bigger at present, as what adopt in the MT instrument is 0dB, 20dB, the variation of 40dB, certain input signal be can not get suitable amplification sometimes, thereby cause unnecessary error; And what adopt in the circuit is general operational amplifier, and its temperature is floated greatly, and for the electrical method exploration instrument for geology of often working in the open air, its variation of ambient temperature is big, can produce very big error when measuring small-signal; In addition, in instrument, also be provided with several active filters separately, owing to increased active device, thereby increased noise, can produce very mistake to amplifying small-signal.
Summary of the invention
The object of the present invention is to provide a kind of grade of difference little, error is little, preposition amplification of the precision isolated amplifier that noise is low and filtering circuit.
The objective of the invention is to be achieved through the following technical solutions: it is by input protection circuit, buffer circuit, at least two-stage is amplified and filtering circuit formations of contacting successively, and preferred version is: described amplification and filtering circuit are connected and composed in turn by three grades or level Four amplification and filtering circuit; Described two-stage, three grades or level Four amplify and the circuit structure of filtering circuit suitable identical.
Described amplifier should be selected the zero shift operational amplifier for use; Wave filter is selected passive RC filter for use.
The present invention is owing to adopt multistage many grades of amplifications, and the shelves difference is little, has effectively amplified the signal that varies in size, and has reduced error; Application of cold temperature is floated amplifier in addition, has reduced the influence of variation of ambient temperature to measurement data, has improved precision; Output terminal every grade of amplification has designed passive RC wave filter, compares with active filter to have reduced noise.
Description of drawings
Fig. 1 is a structured flowchart of the present invention;
Fig. 2 is the circuit diagram of one embodiment of the invention.
Embodiment
The invention will be further described below in conjunction with drawings and Examples.
With reference to accompanying drawing 1,2: present embodiment comprises input protection circuit 1, and buffer circuit amplifies and filtering circuit for 2, three grades; Input protection circuit 1, buffer circuit 2, first order amplification and filtering circuit 3, second level amplification and filtering circuit 4 and third level amplification and filtering circuit 5 connect in turn; Three grades amplify and the filtering circuit circuit structure identical.Input protection circuit 1 comprises diode D
1, D
2, by resistance R
0, capacitor C
0The filtering cutoff frequency of forming is the filtering circuit of 300Hz-1.8kHz, resistance R
0One termination signal input part, the other end and diode D
1Negative pole, diode D
2Positive pole, capacitor C
0One end connects, diode D
1Positive pole meet+V diode D
2Negative pole connect-V capacitor C
0Other end ground connection.Present embodiment filtering cutoff frequency is chosen as 320Hz, and the homophase input is to improve input impedance; Described buffer circuit 2 comprises operation buffer U
0, adopt chip LTC1250, resistance R
0Output terminal and operation buffer U
0In-phase end connect operation buffer U
0Output terminal be connected with its end of oppisite phase; Three grades are amplified and each grade of filtering circuit amplifies and the circuit structure of filtering circuit is identical, by zero shift operational amplifier U
1Form, adopt chip LTC1250 type, the zero shift operational amplifier U of first order amplification and filtering circuit 3
1Homophase termination buffer circuit 2 operation buffer U
0Output terminal, zero shift operational amplifier U
1Anti-phase termination feedback resistance R
1fAnd resistance R is selected in gain
12, R
13, R
14, feedback resistance R wherein
1fBe 21.6k Ω, resistance R is selected in gain
12, R
13, R
14Be respectively 10k Ω, 2.4k Ω, 0.706k Ω, resistance R is selected in gain
12, R
13, R
14The other end passes through analog switch ground connection, the operational amplifier U of amplification and filtering circuit 3
1The output termination by resistance R
11And capacitor C
11The first-order filtering circuit of forming, capacitor C
12Be 50pF-200pF, present embodiment is got 80pF, and cutoff frequency is 320Hz.All the other two- stage amplifying circuit 4,5 structures are the same with the composition of first order amplification and filtering circuit 3, and connect in turn, and the shelves difference is respectively 0dB, 10dB, 20dB, 30dB.
During work, signal enters from the holding circuit input end, is being no more than two diode D
1, D
2Enter operation buffer U after the process RC filtering under the protection voltage condition
0Cushion, enter operational amplifier U then
1Filtering is carried out in output again after carrying out the amplification of certain multiple, has amplified through just entering isolation after three grades of amplification filtering like this.
Present embodiment is selected by three grades 12 grades gain, and shelves difference minimum can reach 10dB, and maximum can reach 90dB, can amplify effectively different signals, has improved the precision of measuring; The operational amplifier of zero shift can reach that very low temperature is floated and high precision in addition.
Claims (7)
1, preposition amplification of a kind of precision isolated amplifier and filtering circuit is characterized in that, it is by input protection circuit, buffer circuit, and two-stage is amplified and the filtering circuit formation of contacting successively at least.
2, preposition amplification of precision isolated amplifier according to claim 1 and filtering circuit is characterized in that, described amplification and filtering circuit amplify by three grades and filtering circuit connects and composes in turn.
3, preposition amplification of precision isolated amplifier according to claim 1 and filtering circuit is characterized in that, described amplification and filtering circuit are amplified by level Four and filtering circuit connects and composes in turn.
According to claim 1 or preposition amplification of 2 or 3 described precision isolated amplifiers and filtering circuit, it is characterized in that 4, the circuit structure of described amplifications at different levels and filtering circuit is identical.
5, according to claim 1 or preposition amplification of 2 or 3 described precision isolated amplifiers and filtering circuit, it is characterized in that described input protection circuit comprises diode D
1, D
2, by resistance R
0, capacitor C
0The filtering circuit of forming, resistance R
0One termination signal input part, the other end and diode D
1Negative pole, diode D
2Positive pole, capacitor C
0One end connects, diode D
1Positive pole meet+V diode D
2Negative pole connect-V capacitor C
0Other end ground connection.
6, according to claim 1 or preposition amplification of 2 or 3 described precision isolated amplifiers and filtering circuit, it is characterized in that described buffer circuit comprises operational amplifier U
0, resistance R
0With operational amplifier U
0In-phase end connect operational amplifier U
0Output terminal be connected with its end of oppisite phase.
7, according to claim 1 or preposition amplification of 2 or 3 described precision isolated amplifiers and filtering circuit, it is characterized in that described amplification and filtering circuit comprise the zero shift operational amplifier, described zero shift operational amplifier U
1Homophase termination operational amplifier U
0Output terminal, its anti-phase termination feedback resistance R
1fAnd resistance R is selected in gain
12, R
13, R
14, resistance R is selected in gain
12, R
13, R
14The other end is by analog switch ground connection, feedback resistance R
1fThe other end and zero shift operational amplifier L
1Output terminal connects, zero shift operational amplifier U
2The output termination is by resistance R
11And capacitor C
11The first-order filtering circuit of forming.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100313124A CN100478707C (en) | 2006-03-08 | 2006-03-08 | Preamplification and filtering circuit for precision isolated amplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100313124A CN100478707C (en) | 2006-03-08 | 2006-03-08 | Preamplification and filtering circuit for precision isolated amplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1811487A true CN1811487A (en) | 2006-08-02 |
| CN100478707C CN100478707C (en) | 2009-04-15 |
Family
ID=36844523
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100313124A Expired - Fee Related CN100478707C (en) | 2006-03-08 | 2006-03-08 | Preamplification and filtering circuit for precision isolated amplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100478707C (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102944250A (en) * | 2012-11-20 | 2013-02-27 | 中国航天科技集团公司第五研究院第五一〇研究所 | Front-end conditioning circuit for measuring high impedance weak signal |
| CN107948866A (en) * | 2018-01-04 | 2018-04-20 | 成都威邦科技有限公司 | A kind of feedback interference low distortion audio frequency broadcast system |
| CN110260773A (en) * | 2019-05-22 | 2019-09-20 | 北京清科电子有限责任公司 | A kind of preposition conditioning device of the current vortex sensor of Low Drift Temperature |
| CN111366546A (en) * | 2019-09-11 | 2020-07-03 | 添可智能科技有限公司 | Cleanliness detection method, cleaning device and storage medium |
| CN112910436A (en) * | 2019-12-03 | 2021-06-04 | 华润微集成电路(无锡)有限公司 | Second-order low-pass active filter integrated circuit for realizing demodulation sampling |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2632135A1 (en) * | 1988-05-31 | 1989-12-01 | Liger Rene | Filtering circuit |
| RU2205428C1 (en) * | 2001-12-19 | 2003-05-27 | Солодилов Леонид Николаевич | Seismic signal recorder |
-
2006
- 2006-03-08 CN CNB2006100313124A patent/CN100478707C/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102944250A (en) * | 2012-11-20 | 2013-02-27 | 中国航天科技集团公司第五研究院第五一〇研究所 | Front-end conditioning circuit for measuring high impedance weak signal |
| CN107948866A (en) * | 2018-01-04 | 2018-04-20 | 成都威邦科技有限公司 | A kind of feedback interference low distortion audio frequency broadcast system |
| CN107948866B (en) * | 2018-01-04 | 2023-09-29 | 成都威邦科技有限公司 | Feedback interference low-distortion audio playing system |
| CN110260773A (en) * | 2019-05-22 | 2019-09-20 | 北京清科电子有限责任公司 | A kind of preposition conditioning device of the current vortex sensor of Low Drift Temperature |
| CN111366546A (en) * | 2019-09-11 | 2020-07-03 | 添可智能科技有限公司 | Cleanliness detection method, cleaning device and storage medium |
| CN112910436A (en) * | 2019-12-03 | 2021-06-04 | 华润微集成电路(无锡)有限公司 | Second-order low-pass active filter integrated circuit for realizing demodulation sampling |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100478707C (en) | 2009-04-15 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
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Application publication date: 20060802 Assignee: HUNAN QIANGJUN TECHNOLOGY CO., LTD. Assignor: Central South University Contract record no.: 2013430000151 Denomination of invention: Preamplification and filtering circuit for precision isolated amplifier Granted publication date: 20090415 License type: Exclusive License Record date: 20130826 |
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| LICC | Enforcement, change and cancellation of record of contracts on the licence for exploitation of a patent or utility model | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090415 Termination date: 20160308 |
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| CF01 | Termination of patent right due to non-payment of annual fee |