CN1414701A - High common mode rejection ratio preamplifier - Google Patents
High common mode rejection ratio preamplifier Download PDFInfo
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- CN1414701A CN1414701A CN 02129065 CN02129065A CN1414701A CN 1414701 A CN1414701 A CN 1414701A CN 02129065 CN02129065 CN 02129065 CN 02129065 A CN02129065 A CN 02129065A CN 1414701 A CN1414701 A CN 1414701A
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- resistance
- amplifier
- operational amplifier
- output
- operational
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Abstract
A preamplifier with high common-mode suppression ratio includes connect output end of parallel dual mode instrumentation amplifier with coupling circuit of two groups of resistance-capacitance separately, the circuits of two groups of resistance-capacitance connected with the input end of integrated instrumentation amplifier in next stage amplifier separately, the common-mode signal sampling circuit connected with outupt end of parallel dual mode instrumentation amplifier separately and the coupling circuit of two groups of resistance-capacitance also connected with common-mode signal sampling circuit so that it is made to have the advatnages as follows: the common-mode suppression ratio being infinite, the output being output signal of dual end differential action and no relationship to the matching of its peripheral resistance.
Description
Technical field
The invention belongs to the control class, relate in particular to the electronic measurement and control technology.
Background technology
At present, known instrument and meter and TT﹠C system are all moved under strong interference environment usually, exist stronger common mode disturbances especially, thereby high cmrr is the most important index of differential preamplifier.Present differential preamplifier mostly adopts the instrumentation amplifier of three amplifiers or double operational form to constitute, or adopts special differential preamplifier integrated chip.When the instrumentation amplifier that adopts three amplifiers or double operational form constitutes difference preliminary amplifier circuit, its circuit complexity, the cost height, manufacturability is poor, and performance is low.The differential preamplifier integrated chip price of function admirable is very expensive, and at a low price the performance of chip is very relatively poor, thereby is difficult to reach both guaranteed performances, keeps the needs of aspect such as with low cost again.
Summary of the invention
The purpose of this invention is to provide a kind of high common mode rejection ratio preamplifier, solve an above-mentioned difficult problem, levied performance, keep many-sided needs such as with low cost again to satisfy both to have protected.
The object of the present invention is achieved like this: high common mode rejection ratio preamplifier, the output of its parallel connection type double operational instrumentation amplifier is connected with the input of two groups of resaistance-capacity coupling circuits respectively, the output of two groups of resaistance-capacity coupling circuits is connected with integral instrument amplifier input terminal in the post-amplifier respectively, the common-mode signal sample circuit is connected with the output of parallel connection type double operational instrumentation amplifier respectively, and two groups of resaistance-capacity coupling circuits also are connected with the common mode signal sampling circuit.
Because the present invention has adopted above technical scheme, thereby has following advantage:
1, common-mode rejection ratio is infinitely great, is output as the differential output signal of both-end, and resistors match degree peripheral with it is irrelevant.
2, adopt the integral instrument amplifier, and adopt resaistance-capacity coupling circuit isolated DC signal, thereby obtain higher difference mode gain, thereby obtain very high common-mode rejection ratio performance.
3, overall structure is simple, the high cmrr dependable performance, and product easily system is easily sold.Can be widely used in various bioelectricity detecting instruments such as electrocardio, brain electricity and the various TT﹠C system, economic and social benefit is remarkable.
Description of drawings
Fig. 1 is the circuit theory schematic diagram of a kind of high common mode rejection ratio preamplifier of the present invention;
Fig. 2 is the circuit theory schematic diagram of another kind of high common mode rejection ratio preamplifier of the present invention.
Embodiment
Below in conjunction with accompanying drawing enforcement of the present invention is done as detailed below:
In Fig. 1, high common mode rejection ratio preamplifier, its parallel connection type double operational instrumentation amplifier is by operational amplifier A
1, operational amplifier A
2, resistance R
1, R
2, R
3Constitute, two groups of resaistance-capacity coupling circuits are respectively by capacitor C
1, resistance R
6And capacitor C
2, resistance 7 constitutes, post-amplifier is by integral instrument amplifier A
4, resistance R
GConstitute, the common-mode signal sample circuit is by resistance R
4, R
5, R
WConstitute.
Wherein, operational amplifier A
1, operational amplifier A
2Output respectively through and capacitor C
1, capacitor C
2With integral instrument amplifier A
4Input connect.Resistance R
1Respectively with operational amplifier A
1, operational amplifier A
2Input connect.Resistance R
2, R
3Respectively with operational amplifier A
1, operational amplifier A
2Output and resistance R
1Two ends connect.Resistance R
4, R
W, R
5Be parallel to operational amplifier A after being linked in sequence
1, operational amplifier A
2Output.Resistance R
6, resistance R
7An end and resistance R
WThe adjustable side connect, the other end respectively with integral instrument amplifier A
4Two inputs connect.Resistance R
GWith integral instrument amplifier A
4Another two input connect.
In Fig. 2, in the another kind of circuit of high common mode rejection ratio preamplifier, its parallel connection type double operational instrumentation amplifier is by operational amplifier A
1, operational amplifier A
2, resistance R
1, R
2, R
3Constitute, two groups of resaistance-capacity coupling circuits are respectively by capacitor C
1, resistance R
6And capacitor C
2, resistance 7 constitutes, post-amplifier is by integral instrument amplifier A
4, resistance R
GConstitute, the common-mode signal sample circuit is by operational amplifier A
4, resistance R
4, R
5, R
WConstitute.
Wherein, operational amplifier A
1, operational amplifier A
2Output respectively through and capacitor C
1, capacitor C
2With integral instrument amplifier A
4Input connect.Resistance R
1Respectively with operational amplifier A
1, operational amplifier A
2Input connect.Resistance R
2, R
3Respectively with operational amplifier A
1, operational amplifier A
2Output and resistance R
1Two ends connect.Resistance R
4, R
W, R
5Be parallel to operational amplifier A after being linked in sequence
1, operational amplifier A
2Output.Resistance R
6, resistance R 7 an end and operational amplifier A
3Output connect, the other end respectively with integral instrument amplifier A
4Two inputs connect.Operational amplifier A
3Input one end and resistance R
WThe adjustable side connect another input and output and resistance R
6, resistance 7 continuous end connect.Resistance R
GWith integral instrument amplifier A
4Another two input connect.
In above-mentioned Fig. 1, Fig. 2, for obtaining better practical function, operational amplifier A 1, A2, A3 can adopt high-precision single supply or duplicate supply operational amplifier, as the OP777 model.A4 can adopt high-precision single supply or duplicate supply instrumentation amplifier, as the AD620 model.
Resistance R 1, R2, R3, R4, R5, R6, R7, R
GCan adopt high-precision metal film resistor.R
WCan adopt high-precision potentiometer.
Capacitor C1, C2 can adopt the little capacitor of electric leakage.
When the present invention used in reality, parallel connection type double operational instrumentation amplifier had a very outstanding advantage, and the common-mode rejection ratio that is exactly it is for infinitely great, and the matching degree of resistance peripheral with it is irrelevant.In addition, parallel connection type double operational instrumentation amplifier is output as the differential output signal of both-end, if will no longer have this advantage during only with single-ended output signal.So the present invention uses integral instrument amplifier A in the back level
4, the differential output signal of both-end is converted to single-ended output signal commonly used.The integral instrument amplifier has better performance, but because its common-mode rejection ratio is proportional to difference mode gain, and, when directly the application integration instrumentation amplifier is as preamplifier, can not obtain the highest common-mode rejection ratio performance because there is higher offset voltage in device and usually has bigger dc offset voltage (polarizing voltage during as the detection of biological signal of telecommunication and the zero migration voltage in the transducer) in the signal source.Therefore, the back level is used the integral instrument amplifier in the present invention, and adopts resaistance-capacity coupling circuit isolated DC signal, thereby makes the integral instrument amplifier obtain higher difference mode gain, thereby obtains very high common-mode rejection ratio performance.Reduce the common-mode rejection ratio of circuit integral body for fear of not matching of resaistance-capacity coupling circuit, by resistance R
4, R
5And R
WAnd amplifier constitutes the common-mode signal sample circuit, the resistance terminal of the resaistance-capacity coupling circuit of driving script ground connection.
High cmrr differential preamplifier of the present invention can be applicable in various instrument and meters and the TT﹠C system, especially in the bioelectricity detecting instrument such as electrocardio and brain electricity.
Claims (3)
1. high common mode rejection ratio preamplifier, it is characterized in that, the output of parallel connection type double operational instrumentation amplifier is connected with the input of two groups of resaistance-capacity coupling circuits respectively, the output of two groups of resaistance-capacity coupling circuits is connected with integral instrument amplifier input terminal in the post-amplifier respectively, the common-mode signal sample circuit is connected with the output of parallel connection type double operational instrumentation amplifier respectively, and two groups of resaistance-capacity coupling circuits also are connected with the common mode signal sampling circuit.
2. a kind of high common mode rejection ratio preamplifier according to claim 1 is characterized in that, parallel connection type double operational instrumentation amplifier is by operational amplifier A
1, operational amplifier A
2, resistance R
1, R
2, R
3Constitute, two groups of resaistance-capacity coupling circuits are respectively by capacitor C
1, resistance R
6And capacitor C
2, resistance 7 constitutes, post-amplifier is by integral instrument amplifier A
4, resistance R
GConstitute, the common-mode signal sample circuit is by resistance R
4, R
5, R
WConstitute;
Wherein, operational amplifier A
1, operational amplifier A
2Output respectively through and capacitor C
1, capacitor C
2With integral instrument amplifier A
4Input connect resistance R
1Respectively with operational amplifier A
1, operational amplifier A
2Input connect resistance R
2, R
3Respectively with operational amplifier A
1, operational amplifier A
2Output and resistance R
1Two ends connect resistance R
4, R
W, R
5Be parallel to operational amplifier A after being linked in sequence
1, operational amplifier A
2Output; Resistance R
6, resistance R
7An end and resistance R
WThe adjustable side connect, the other end respectively with integral instrument amplifier A
4Two inputs connect resistance R
GWith integral instrument amplifier A
4Another two input connect.
3. the described a kind of high common mode rejection ratio preamplifier of root root claim 2 is characterized in that operational amplifier A
3Input one end and resistance R
WThe adjustable side connect another input and output and resistance R
6, resistance 7 continuous end connect.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021290652A CN100517959C (en) | 2002-08-30 | 2002-08-30 | High common mode rejection ratio preamplifier |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021290652A CN100517959C (en) | 2002-08-30 | 2002-08-30 | High common mode rejection ratio preamplifier |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1414701A true CN1414701A (en) | 2003-04-30 |
| CN100517959C CN100517959C (en) | 2009-07-22 |
Family
ID=4746126
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB021290652A Expired - Fee Related CN100517959C (en) | 2002-08-30 | 2002-08-30 | High common mode rejection ratio preamplifier |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100517959C (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102499671A (en) * | 2011-11-28 | 2012-06-20 | 中国科学技术大学 | Ventricular repolarization high-frequency wave double-limb electrode detecting device |
| CN103095233A (en) * | 2013-01-23 | 2013-05-08 | 电子科技大学 | Amplifier eliminating direct current offsets |
| CN104000583A (en) * | 2014-05-04 | 2014-08-27 | 山东中医药大学 | Electrocardiosignal preamplifier circuit |
| CN106943142A (en) * | 2017-03-16 | 2017-07-14 | 深圳麦格米特电气股份有限公司 | A kind of electroretinogram（ERG）The signal amplifier of portable detection system |
-
2002
- 2002-08-30 CN CNB021290652A patent/CN100517959C/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102499671A (en) * | 2011-11-28 | 2012-06-20 | 中国科学技术大学 | Ventricular repolarization high-frequency wave double-limb electrode detecting device |
| CN102499671B (en) * | 2011-11-28 | 2013-11-06 | 中国科学技术大学 | Ventricular repolarization high-frequency wave double-limb electrode detecting device |
| CN103095233A (en) * | 2013-01-23 | 2013-05-08 | 电子科技大学 | Amplifier eliminating direct current offsets |
| CN103095233B (en) * | 2013-01-23 | 2015-10-28 | 电子科技大学 | The amplifier of cancellation of DC offset |
| CN104000583A (en) * | 2014-05-04 | 2014-08-27 | 山东中医药大学 | Electrocardiosignal preamplifier circuit |
| CN106943142A (en) * | 2017-03-16 | 2017-07-14 | 深圳麦格米特电气股份有限公司 | A kind of electroretinogram（ERG）The signal amplifier of portable detection system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100517959C (en) | 2009-07-22 |
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| C06 | Publication | ||
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| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| EE01 | Entry into force of recordation of patent licensing contract |
Assignee: Shenzhen Yixinfa Electronics Co.,Ltd. Assignor: Tianjin University Contract record no.: 2011440000525 Denomination of invention: High common mode rejection ratio preamplifier Granted publication date: 20090722 License type: Exclusive License Open date: 20030430 Record date: 20110616 |
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| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090722 Termination date: 20120830 |