CN203658433U - High-sensitivity wide-range current amplification conversion circuit - Google Patents
High-sensitivity wide-range current amplification conversion circuit Download PDFInfo
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- CN203658433U CN203658433U CN201320748699.0U CN201320748699U CN203658433U CN 203658433 U CN203658433 U CN 203658433U CN 201320748699 U CN201320748699 U CN 201320748699U CN 203658433 U CN203658433 U CN 203658433U
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Abstract
The utility model relates to the current measurement technology and provides a high-sensitivity wide-range current amplification conversion circuit which comprises a current-voltage conversion circuit and a voltage-frequency conversion circuit. The output end of the current-voltage conversion circuit is connected with and the voltage-frequency conversion circuit. The high-sensitivity wide-range current amplification conversion circuit can measure fA level current at a lower limit, the measuring range can span more than 8 magnitudes, only one instrumentation amplifier is employed by the first level of the circuit, the shift technology and the voltage-frequency conversion technology are introduced at the same time, and the disadvantages of complex circuit structure, narrow measuring range, short output signal transmission distance, large fluctuation of measurement results in weak signal measurement are solved.
Description
Technical field
The utility model relates to current measurement techniques, and particularly a kind of high sensitivity wide-range electric current amplifies translation circuit.
Background technology
Be a difficult point of signal processing for the measurement of fA level weak current always, due to the interference of leakage current, seldom have electronics components and parts can cover the measurement range of this range, and many fields of measurement need to be carried out the measurement of fA level electric current.Measure as the nuclear radiation detector of nuclear technology field, accelerator beam monitoring, PH meter, photoelectron stream, often need to carry out weak current signal measurement.Common mode has the transistor amplification of the separation of adopting and the operational amplifier of a few Low-bias Current to amplify at present.And a lot of electronic devices and components temperature drift in the time of weak signal measurement is very serious, measurement result is easy to be subject to variation of ambient temperature to affect.
In the occasion that has weak current signal measurement, generally all wish that measurement instrument can cross over very wide range, as 8 above magnitudes, and single amplifying circuit generally can only be crossed over three to four magnitudes, cannot meet the demands at all.Common way is the amplifying circuit that adopts multi-channel parallel, realizes range switching by switching the mode of amplifying circuit.The cost of doing is like this quantity that has increased components and parts, the volume that has increased circuit and power consumption.
A kind of common structure form of weak current amplifying circuit is electric current-frequency-conversion circuit, after utilizing electronic switch control inputs electric current to little capacitance integral, triggers the pulse signal of monostable oscillatory circuit output frequency equal proportion.The advantage of this circuit is simple in structure, and subsequent conditioning circuit only need carry out counting rate measurement, can extrapolate the size of input current.Shortcoming is in the time of measurement lower limit, and circuit output frequency is very low, and the response time is very slow.
The another kind of common structure form of weak current amplifying circuit utilizes operational amplifier that current signal is enlarged into after voltage signal, utilizes digital circuit to carry out AD conversion, is converted to digital signal and measures.This circuit advantage is that amplifying circuit is simple, only need one-level current-voltage amplifying circuit, shortcoming is that simple voltage signal can not carry out long-distance transmissions, cannot meet the demand of remote measurement, and need to introduce digital circuit, have the shortcomings such as number-Mo disturbs, measurement result fluctuation big rise and fall.
Summary of the invention
The purpose of this utility model is exactly the weak point in order to overcome above-mentioned background technology, provides a kind of high sensitivity wide-range electric current to amplify translation circuit, and its lower limit can be measured fA level electric current, range ability can be crossed over more than 8 order of magnitude.This circuit first order only adopts a slice instrument amplifier, introduces gear shift technology and voltage-frequency converter technique simultaneously, circuit structure complexity while having solved weak signal measurement, the shortcoming such as range ability is narrow, output signal transmission range is short, measurement result fluctuation is large.
The purpose of this utility model is achieved by the following technical measures: a kind of high sensitivity wide-range electric current amplifies translation circuit, comprise current-voltage conversion circuit and voltage-frequency translation circuit, the output terminal of described current-voltage conversion circuit is connected with voltage-frequency translation circuit, described current-voltage conversion circuit is by instrument amplifier U1, current feedback resistance R 1 ~ R3, dry-reed relay K switch 2, K3 composition, current input terminal Iin to be measured is connected with the input end of instrument amplifier U1, R1, R2, R3 is the current feedback resistance of three shift parallel connections, R1>>R2>GreatT. GreaT.GTR3, resistance R 1 is connected between the input end and output terminal of instrument amplifier U1, dry-reed relay K switch 2, K3 respectively with resistance R 2, after R3 series connection, be connected between the input end and output terminal of instrument amplifier U1, described voltage-frequency translation circuit is made up of voltage-frequency conversion module U2 and integrating capacitor Cn thereof, and the input end of voltage-frequency conversion module U2 is connected with the output signal V1 of current-voltage conversion circuit.
The technical program is utilized the amplifier of the low-down instrument amplifier U1 of bias current as the signal first order, utilizes Voltage Feedback method that current signal is converted to voltage signal.Utilize high insulativity dry-reed relay control to select the resistance of feedback resistance, widen the range ability of circuit.Measure in order to facilitate the long-distance transmissions of signal and to gather, after the first order, introduce voltage-frequency translation circuit, voltage signal is converted to the square-wave signal that frequency is directly proportional to voltage, and subsequent conditioning circuit, as long as determine gear and the pulsed frequency of input stage, can be determined the size of input current.Exist because voltage-frequency translation circuit has charge integration circuit, signal voltage signal has been played to the effect of integral filtering, reduced the undulatory property of output signal.
In technique scheme, input end operating voltage changes the output signal reverse excursion causing when being suppressed at high-amplification-factor gear shift, be provided with a pressure release resistance of controlling by dry-reed relay Ks at the input end of instrument amplifier U1, be used for providing a boosting voltage to input end in the time of gear switch, prevent that recoil from appearring in amplifier out, reduced the gear switch time.
In technique scheme, the output terminal of described instrument amplifier U1 is provided with a voltage stabilizing diode Dc, the maximum output voltage that is used for limiting instrument amplifier U1 is all the time lower than the saturated output voltage of amplifier, amplifier saturation can prevent like this that input end from occurring large electric current suddenly time and damage components and parts.
In technique scheme, the voltage signal of current-voltage conversion circuit output utilizes voltage-frequency translation circuit to be converted to the square-wave signal that pulse height is certain, and the sensitivity of circuit can change by the reference current of Circuit tuning.Can increase one-level in voltage-frequency translation circuit rear end and follow amplifying circuit, improve the transmission range of signal.
Usefulness of the present utility model is: its lower limit can be measured fA level electric current, range ability can be crossed over more than 8 order of magnitude.This circuit first order only adopts a slice instrument amplifier, introduces gear shift technology and voltage-frequency converter technique simultaneously, circuit structure complexity while having solved weak signal measurement, the shortcoming such as range ability is narrow, output signal transmission range is short, measurement result fluctuation is large.
Accompanying drawing explanation
Fig. 1 is the connection layout that the utility model high sensitivity wide-range electric current amplifies translation circuit.
Fig. 2 is the schematic diagram that in the utility model, voltage-frequency conversion module is multiple integrated circuit combinations.
Fig. 3 is the schematic diagram that in the utility model, voltage-frequency conversion module is single integrated circuit.
Embodiment
Below in conjunction with drawings and Examples, the utility model will be further described.
As shown in Figure 1, this embodiment provides a kind of high sensitivity wide-range electric current to amplify translation circuit, comprises current-voltage conversion circuit and voltage-frequency translation circuit, and the output terminal of described current-voltage conversion circuit is connected with voltage-frequency translation circuit, described current-voltage conversion circuit is by instrument amplifier U1, current feedback resistance R 1 ~ R3, the dry-reed relay K switch 2 that insulation resistance is very high, K3 composition, current input terminal Iin to be measured is connected with the input end of instrument amplifier U1, R1, R2, R3 is the current feedback resistance of three shift parallel connections, R1>>R2>GreatT. GreaT.GTR3, resistance R 1 is connected between the input end and output terminal of instrument amplifier U1, dry-reed relay K switch 2, K3 respectively with resistance R 2, after R3 series connection, be connected between the input end and output terminal of instrument amplifier U1.Described current feedback resistance R 2 and R3 are by whether conducting of dry-reed relay control.R1 directly connects, and guarantees all the time, in conducting state, to guarantee like this in the time that K2, K3 all disconnect, and the feedback resistance maximum between circuit input/output terminal is no more than R1, and while avoiding unsettled, feedback resistance is infinitely great and make circuit produce the self-oscillation amplifying.In order to measure weak current signal, as the current signal of tens fA, amplifier U1 need adopt the amplifier that bias current is very little, as INA116, LMC6001, meanwhile, the unsettled layout of amp.in, R1 adopts the less large resistance of temperature coefficient, and resistance is between 1G ~ 1T.
Because R1 is very large, in the time of K2 or K3 disconnection, the electric current of input end can not be released from R1 end rapidly, can cause U1 input end changing operate-point, thereby make output end voltage anti-phase.In order to overcome this difficulty, access a reference voltage Vs at current input terminal by dry-reed relay K switch s, when K2, K3 disconnect moment, allow Ks closure, give reference potential of U1 input end, make amplifier all the time in normal operating conditions.Ks closure time is very short, and in 1s, the output signal in this time period can be deducted by follow-up signal processing unit, therefore can not affect measurement result.
In the time of weak signal measurement, in the time that input end Iin has compared with heavy current impact, can make amplifier U1 enter protection duty, need the long period to recover.In order to overcome this difficulty, the polarity that is connected to the voltage stabilizing diode Dc(Dc of a restriction output voltage amplitude at U1 output terminal is determined by the polarity of U1 output signal), in the time that U1 output voltage amplitude exceedes the voltage breakdown Vz of voltage stabilizing diode, output voltage will be limited in Vz.Like this, after impacting in the past, circuit can return to normal operating conditions very soon.
Described voltage-frequency translation circuit is made up of voltage-frequency conversion module U2 and integrating capacitor Cn thereof, and the input end of voltage-frequency conversion module U2 is connected with the output signal V1 of current-voltage conversion circuit.
Voltage-frequency conversion module U2 is responsible for the voltage signal of U1 output to be converted to the square-wave signal of frequency equal proportion.U2 can be single integrated circuit chip, as XR4151, AD537, LM131, can be also the functional module that multiple integrated circuit (IC) chip combine, as the combination of LM131 and LF356.Because Cn has the effect of integration, therefore, can filter out the AC noise in U1 output signal.
Be illustrated in figure 2 the embodiment that in the utility model, voltage-frequency conversion module U2 adopts multiple integrated circuit combinations to form.Wherein, U2A is voltage-frequency conversion integrated circuit, and as LM131, U2B is operational amplifier, and as LF356, Cn is integrating capacitor, Ct and Rt composition RC oscillatory circuit.Due to the use of U2B, the measuring accuracy of circuit is improved, and is conducive to measure weak voltage signal.
Be illustrated in figure 3 the embodiment of voltage-frequency conversion module U2 employing single integrated circuit in the utility model.Voltage-frequency conversion module U2 is XR4151, AD537 or LM131.Wherein, Cn is integrating capacitor, and Vref is the reference voltage of U2 internal logic circuit.Because the utility model first order circuit has carried out pre-amplification processing to output current signal, therefore less demanding to follow-up V-F translation circuit, therefore, two kinds of embodiment all can meet user demand.
In order to improve the precision of the utility model measurement result under different environment temperatures, can on circuit board, arrange a temperature sensor, in survey frequency and gear signal, record temperature value, utilize in advance current source to measure the temperature curve of each grade of circuit, be used for measurement result to carry out temperature correction.
The content that this instructions is not described in detail belongs to the known prior art of professional and technical personnel in the field.
Claims (4)
1. high sensitivity wide-range electric current amplifies a translation circuit, it is characterized in that: comprise current-voltage conversion circuit and voltage-frequency translation circuit, the output terminal of described current-voltage conversion circuit is connected with voltage-frequency translation circuit, described current-voltage conversion circuit is by instrument amplifier U1, current feedback resistance R 1 ~ R3, dry-reed relay K switch 2, K3 composition, current input terminal Iin to be measured is connected with the input end of instrument amplifier U1, R1, R2, R3 is the current feedback resistance of three shift parallel connections, R1>>R2>GreatT. GreaT.GTR3, resistance R 1 is connected between the input end and output terminal of instrument amplifier U1, dry-reed relay K switch 2, K3 respectively with resistance R 2, after R3 series connection, be connected between the input end and output terminal of instrument amplifier U1, described voltage-frequency translation circuit is made up of voltage-frequency conversion module U2 and integrating capacitor Cn thereof, and the input end of voltage-frequency conversion module U2 is connected with the output signal V1 of current-voltage conversion circuit.
2. high sensitivity wide-range electric current according to claim 1 amplifies translation circuit, it is characterized in that: the input end of described instrument amplifier U1 is provided with a pressure release resistance of controlling by dry-reed relay Ks.
3. high sensitivity wide-range electric current according to claim 1 amplifies translation circuit, it is characterized in that: the output terminal of described instrument amplifier U1 is provided with a voltage stabilizing diode Dc.
4. high sensitivity wide-range electric current according to claim 1 amplifies translation circuit, it is characterized in that: described voltage-frequency translation circuit output terminal is set up and followed amplifying circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320748699.0U CN203658433U (en) | 2013-11-25 | 2013-11-25 | High-sensitivity wide-range current amplification conversion circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201320748699.0U CN203658433U (en) | 2013-11-25 | 2013-11-25 | High-sensitivity wide-range current amplification conversion circuit |
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| CN203658433U true CN203658433U (en) | 2014-06-18 |
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| CN201320748699.0U Expired - Fee Related CN203658433U (en) | 2013-11-25 | 2013-11-25 | High-sensitivity wide-range current amplification conversion circuit |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104597316A (en) * | 2015-01-08 | 2015-05-06 | 聚光科技(杭州)股份有限公司 | Weak current detecting device and method |
| CN104698375A (en) * | 2015-03-17 | 2015-06-10 | 西安交通大学 | SF6 breaker electrical endurance monitor system based on weak signal processing |
| CN106197730A (en) * | 2016-08-30 | 2016-12-07 | 南京双京电器集团有限公司 | A kind of temperature frequency conversion equipment |
| CN107703351A (en) * | 2017-09-27 | 2018-02-16 | 成都兴睿宝电子科技有限公司 | A kind of Larger Dynamic micro-current sensing circuit |
| CN108109588A (en) * | 2018-01-10 | 2018-06-01 | 京东方科技集团股份有限公司 | Voltage collection circuit and method, external compensation circuit and display device |
| CN110618309A (en) * | 2019-09-20 | 2019-12-27 | 北京大学 | Semiconductor detector leakage current measuring device and measuring method |
| CN111108398A (en) * | 2017-09-29 | 2020-05-05 | 勃林格殷格翰维特梅迪卡有限公司 | Testing and calibration of circuit arrangements |
| CN111448464A (en) * | 2017-12-09 | 2020-07-24 | 深圳市丹砂科技有限公司 | Current sensor for biomedical measurements |
| CN112533331A (en) * | 2020-12-15 | 2021-03-19 | 广东新昇电业科技股份有限公司 | Automatic following constant power circuit of LED constant current source |
| CN112533330A (en) * | 2020-12-15 | 2021-03-19 | 广东新昇电业科技股份有限公司 | LED constant current driving power supply |
-
2013
- 2013-11-25 CN CN201320748699.0U patent/CN203658433U/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104597316A (en) * | 2015-01-08 | 2015-05-06 | 聚光科技(杭州)股份有限公司 | Weak current detecting device and method |
| CN104698375A (en) * | 2015-03-17 | 2015-06-10 | 西安交通大学 | SF6 breaker electrical endurance monitor system based on weak signal processing |
| CN106197730A (en) * | 2016-08-30 | 2016-12-07 | 南京双京电器集团有限公司 | A kind of temperature frequency conversion equipment |
| CN107703351A (en) * | 2017-09-27 | 2018-02-16 | 成都兴睿宝电子科技有限公司 | A kind of Larger Dynamic micro-current sensing circuit |
| CN111108398A (en) * | 2017-09-29 | 2020-05-05 | 勃林格殷格翰维特梅迪卡有限公司 | Testing and calibration of circuit arrangements |
| CN111448464A (en) * | 2017-12-09 | 2020-07-24 | 深圳市丹砂科技有限公司 | Current sensor for biomedical measurements |
| CN108109588A (en) * | 2018-01-10 | 2018-06-01 | 京东方科技集团股份有限公司 | Voltage collection circuit and method, external compensation circuit and display device |
| CN110618309A (en) * | 2019-09-20 | 2019-12-27 | 北京大学 | Semiconductor detector leakage current measuring device and measuring method |
| CN112533331A (en) * | 2020-12-15 | 2021-03-19 | 广东新昇电业科技股份有限公司 | Automatic following constant power circuit of LED constant current source |
| CN112533330A (en) * | 2020-12-15 | 2021-03-19 | 广东新昇电业科技股份有限公司 | LED constant current driving power supply |
| CN112533331B (en) * | 2020-12-15 | 2023-04-07 | 广东新昇电业科技股份有限公司 | Automatic following constant power circuit of LED constant current source |
| CN112533330B (en) * | 2020-12-15 | 2023-04-07 | 广东新昇电业科技股份有限公司 | LED constant current driving power supply |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20151204 Address after: 19 No. 430000 Hubei province Wuhan city Jiangxia District Yangqiao Lake Avenue Patentee after: Wuhan Haiwang Nuclear Energy Equipment Engineering Co., Ltd. Address before: 430064 Zhongshan Road, Wuchang, Hubei, No. 450, Patentee before: No.719 Inst. China Shipping Heavy Industry Group Corp. |
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| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140618 Termination date: 20171125 |