CN201926944U - Microampere precise constant flow source circuit - Google Patents
Microampere precise constant flow source circuit Download PDFInfo
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- CN201926944U CN201926944U CN2010206662440U CN201020666244U CN201926944U CN 201926944 U CN201926944 U CN 201926944U CN 2010206662440 U CN2010206662440 U CN 2010206662440U CN 201020666244 U CN201020666244 U CN 201020666244U CN 201926944 U CN201926944 U CN 201926944U
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Abstract
The utility model relates to a microampere precise constant flow source circuit, which has the technical characteristics that: an inverting input end of a compound amplifier A1 is connected with an anode of a reference supply and one end of a resistance R1, an output end of the compound amplifier A1 is connected with an cathode of the reference supply, the other end of the resistance R1 and one end of a resistance R3, a non-inverting input end of the compound amplifier A1 is connected with a non-inverting input end of a follower amplifier A2 and one end of a resistance R2, an inverting input end of the follower amplifier A2 is connected with an output end of the follower amplifier A2 and a floating B end of a floating power supply, two power output ends of the floating power supply are respectively connected with a power input end of the compound amplifier A1, the floating B end of the floating power supply is connected with an input protection shield terminal of the compound amplifier A1, and the other end of the resistance R2 and the other end of the resistance R3 are connected with a ground wire through a load. The utility model meets the demand on design resolution ratio of the microampere precise constant flow source circuit, and can be widely applied to various fields requiring precision measurement.
Description
Technical field
The utility model belongs to the constant current source field, especially a kind of microampere order precision constant current source circuit.
Background technology
Constant current source has in various electronic measurement circuit and sensor electronics very widely to be used, and is irreplaceable test cell in the occasions such as LED new forms of energy, input and power amplification.The microampere order constant current source is widely used in intelligence instrument and the advanced detection technique especially.Because microampere constant current source output current is little, precision is high, therefore, the microampere constant current source is compared easier be subjected to ripple and The noise in the circuit with general constant-current source circuit, make it be difficult to bring up to 1 resolution of receiving the peace level, can not satisfy the needs of high-acruracy survey.
Summary of the invention
The purpose of this utility model is to overcome the deficiencies in the prior art, provides a kind of reasonable in design and can make resolution reach the 1 microampere order precision constant current source circuit of receiving peace level.
The utility model solves its technical matters and takes following technical scheme to realize:
A kind of microampere order precision constant current source circuit; comprise reference power source; composite amplifier A1; follower amplifier A2; the power supply of floating; resistance R 1; resistance R 2 and resistance R 3; the inverting input of this composite amplifier A1 and the positive pole of reference power source; one end of resistance R 1 is connected; the output terminal of composite amplifier A1 and the negative pole of reference power source; one end of the other end of resistance R 1 and resistance R 3 is connected; the positive input of composite amplifier A1 is connected with the positive input of follower amplifier A2 and an end of resistance R 2; the inverting input of follower amplifier A2 and the output terminal and the power supply of floating the ground B end of floating be connected; two power output ends of power supply floated are connected with the power input of composite amplifier A1 respectively; float power supply the ground B end of floating hold with the input protection shielding of composite amplifier A1 and be connected, the other end of the other end of resistance R 2 and resistance R 3 is connected with ground wire by load jointly.
And described resistance R 1, resistance R 2 and resistance R 3 are used accurate wire-wound resistor.
And described composite amplifier is connected and composed by main amplifier and chopper amplifier.
And described main amplifier adopts the electrometer level precision operational-amplifier of inner integrated a pair of FET field effect transistor, and described chopper amplifier uses the chopper amplifier of high input impedance and low input offset voltage.
Advantage of the present utility model and good effect are:
The utility model uses high-precision device and high precision composite amplifier, follower amplifier and the power supply of floating is organically linked together, thereby reduce the error of generations such as environment temperature, humidity, voltage fluctuation and device self drift to the full extent, satisfied the requirement of the design resolution of microampere order precision constant current source circuit, improved the cost performance of the antijamming capability and the circuit of testing circuit, can be widely used in the every field that needs precision measurement.
Description of drawings
Fig. 1 is a circuit block diagram of the present utility model;
Fig. 2 is a circuit diagram of the present utility model.
Embodiment
Below in conjunction with accompanying drawing the utility model embodiment is further described:
A kind of microampere order precision constant current source circuit, as shown in Figure 1, comprise reference power source Vref, composite amplifier A1, follower amplifier A2, float power supply and resistance R 1, R2, R3, in order to guarantee the precision of constant-current source circuit, described resistance R 1, R2, R3 select the extraordinary accurate wire-wound resistor of stability for use, and its temperature coefficient is better than the 2PPM/ degree.The annexation of this constant-current source circuit is: the positive pole of the inverting input of composite amplifier A1 and reference power source Vref; the end of accurate wire-wound resistor R1 is connected; the negative pole of the output terminal of composite amplifier A1 and reference power source Vref; the other end of accurate wire-wound resistor R1 and the end of accurate wire-wound resistor R3 are connected; the positive input of composite amplifier A1 is connected with the positive input of follower amplifier A2 and the end of accurate wire-wound resistor R2; the inverting input of follower amplifier A2 and the output terminal of follower amplifier A2 and the power supply of floating the ground B end of floating be connected; two power output end+B of power supply float;-B is connected with the power input of composite amplifier A1 respectively; float power supply the ground B end of floating hold B to be connected with the input protection shielding of composite amplifier A1, the other end of the other end of accurate wire-wound resistor R2 and accurate wire-wound resistor R3 is connected with ground wire by load jointly.
The principle of work of this microampere order precision constant current source circuit is: float power supply and follower amplifier A2 are composite amplifier A1 power supply, and composite amplifier A1 is as an ideal amplifier, and when a reference power source Vref was added on the resistance R 1, its electric current was I
R1=Vref/R1, owing to do not have electric current to flow through (input impedance of amplifier is for infinitely great) on the resistance R 2, so V
R3=Vref flows through the electric current I of load
Z=V
R3/ R3=Vref/R3, this electric current all flows through load, and the size of this electric current only depends on Vref and R3, is not subjected to the influence of load size.
Be example with a kind of microampere order precision constant current source circuit shown in Figure 2 below, specify the formation of microampere order precision constant current source circuit.In the figure, form a high-gain composite amplifier jointly by main amplifier N2 and chopper amplifier N3, main amplifier N2 adopts electrometer level precision operational-amplifier, and its inner integrated a pair of FET field effect transistor input impedance is up to 10
13Ohm, its input base flow is 75fA, is far smaller than 1nA, open-loop gain 110dB, common-mode rejection ratio 90dB, N2 also is weak as ideal amplifier with main amplifier.Because input offset voltage 500uV/ ℃ of main amplifier N2 also needs chopper amplifier N3 to cooperate main amplifier N2 to carry out stable output, chopper amplifier N3 is as a kind of high precision chopper amplifier, its input impedance also very high 10
12Ohm, and its input offset voltage is very low has only 1 microvolt, has utilized the low maladjustment voltage of N3, the characteristics of high stable, be combined into a good linearity, good stability, offset voltage very little again be bordering on desirable amplifier.That is to say, because the offset voltage of N3 is very little, about 1 microvolt, by its regulating action, make that the imbalance of N4 is adjusted, its numerical value also is about 1 microvolt, and promptly the offset voltage of whole amplifier also is about 1 microvolt, the offset voltage of whole amplifier is little, so just can be all the more stable when work.
In order to prevent that faint leakage between follower amplifier N3 pin from causing the influence to constant-current source circuit; by stabilivolt V1; V2 and triode V3; V4 and resistance R 1; R2; R3; R4; the power supply of floating that R5 forms is the composite amplifier power supply; power output end+the B of this power supply of floating;-B is connected amplifier N2; the power input of N3 is its power supply; the reference point of follower amplifier N1 (positive input of amplifier N1) is from the input end H of the field effect transistor of composite amplifier; the inverting input of this follower amplifier N1 is connected with the output terminal of follower amplifier N1; float power supply be connected with the input protection of chopper amplifier N3 shielding end B with floating; make that like this input end and the protection mask end of chopper amplifier N3 are idiostatic; further avoid forward and reverse leakage of electric current, be not subjected to the influence of other factors with the electric current that guarantees to flow through load.
Resistance R 13 in this composite amplifier, R14, R6 select the extraordinary accurate wire-wound resistor of stability for use, and its temperature coefficient is better than the 2PPM/ degree, so just can guarantee the highly stable output of amplifier.
It is emphasized that; embodiment described in the utility model is illustrative; rather than it is determinate; therefore the utility model is not limited to the embodiment described in the embodiment; every by those skilled in the art according to other embodiments that the technical solution of the utility model draws, belong to the scope of the utility model protection equally.
Claims (4)
1. microampere order precision constant current source circuit; it is characterized in that: comprise reference power source; composite amplifier A1; follower amplifier A2; the power supply of floating; resistance R 1; resistance R 2 and resistance R 3; the inverting input of this composite amplifier A1 and the positive pole of reference power source; one end of resistance R 1 is connected; the output terminal of composite amplifier A1 and the negative pole of reference power source; one end of the other end of resistance R 1 and resistance R 3 is connected; the positive input of composite amplifier A1 is connected with the positive input of follower amplifier A2 and an end of resistance R 2; the inverting input of follower amplifier A2 is connected with the ground B end of floating of the output terminal and the power supply of floating; two power output ends of power supply floated are connected with the power input of composite amplifier A1 respectively; the B end is connected with the input protection shielding end of composite amplifier A1 with floating floating of power supply, and the other end of the other end of resistance R 2 and resistance R 3 is connected with ground wire by load jointly.
2. a kind of microampere order precision constant current source circuit according to claim 1 is characterized in that: described resistance R 1, resistance R 2 and resistance R 3 are used accurate wire-wound resistor.
3. a kind of microampere order precision constant current source circuit according to claim 1 and 2, it is characterized in that: described composite amplifier is connected and composed by main amplifier and chopper amplifier.
4. a kind of microampere order precision constant current source circuit according to claim 3, it is characterized in that: described main amplifier adopts the electrometer level precision operational-amplifier of inner integrated a pair of FET field effect transistor, and described chopper amplifier uses the chopper amplifier of high input impedance and low input offset voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206662440U CN201926944U (en) | 2010-12-17 | 2010-12-17 | Microampere precise constant flow source circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206662440U CN201926944U (en) | 2010-12-17 | 2010-12-17 | Microampere precise constant flow source circuit |
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| Publication Number | Publication Date |
|---|---|
| CN201926944U true CN201926944U (en) | 2011-08-10 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010206662440U Expired - Fee Related CN201926944U (en) | 2010-12-17 | 2010-12-17 | Microampere precise constant flow source circuit |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105206226A (en) * | 2015-10-08 | 2015-12-30 | 俞德军 | High-precision current drive circuit |
| CN106324303A (en) * | 2016-11-16 | 2017-01-11 | 天津市盛丹电子技术发展有限公司 | Multi-scale precise constant flow source circuit |
| CN106406407A (en) * | 2016-11-16 | 2017-02-15 | 天津市盛丹电子技术发展有限公司 | Multi-range high-accuracy constant current source |
| CN106444952A (en) * | 2016-11-16 | 2017-02-22 | 天津市盛丹电子技术发展有限公司 | High voltage constant current source |
| CN109445501A (en) * | 2018-12-21 | 2019-03-08 | 杭州承诺医疗科技有限公司 | A kind of high-precision high voltage current source circuit |
| CN113721698A (en) * | 2021-09-22 | 2021-11-30 | 苏州锴威特半导体股份有限公司 | High-voltage stabilizing circuit of relative power supply |
-
2010
- 2010-12-17 CN CN2010206662440U patent/CN201926944U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105206226A (en) * | 2015-10-08 | 2015-12-30 | 俞德军 | High-precision current drive circuit |
| CN106324303A (en) * | 2016-11-16 | 2017-01-11 | 天津市盛丹电子技术发展有限公司 | Multi-scale precise constant flow source circuit |
| CN106406407A (en) * | 2016-11-16 | 2017-02-15 | 天津市盛丹电子技术发展有限公司 | Multi-range high-accuracy constant current source |
| CN106444952A (en) * | 2016-11-16 | 2017-02-22 | 天津市盛丹电子技术发展有限公司 | High voltage constant current source |
| CN109445501A (en) * | 2018-12-21 | 2019-03-08 | 杭州承诺医疗科技有限公司 | A kind of high-precision high voltage current source circuit |
| CN113721698A (en) * | 2021-09-22 | 2021-11-30 | 苏州锴威特半导体股份有限公司 | High-voltage stabilizing circuit of relative power supply |
| CN113721698B (en) * | 2021-09-22 | 2022-05-31 | 苏州锴威特半导体股份有限公司 | High-voltage stabilizing circuit of relative power supply |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20110810 Termination date: 20131217 |