CN207263686U - A kind of high-precision reversely addition type potentiostat and IV converted measurement circuits - Google Patents
A kind of high-precision reversely addition type potentiostat and IV converted measurement circuits Download PDFInfo
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- CN207263686U CN207263686U CN201721052693.4U CN201721052693U CN207263686U CN 207263686 U CN207263686 U CN 207263686U CN 201721052693 U CN201721052693 U CN 201721052693U CN 207263686 U CN207263686 U CN 207263686U
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- operational amplifier
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Abstract
The utility model proposes a kind of high-precision reversely addition type potentiostat and IV converted measurement circuits, including：Potentiostat, IV conversion circuit, electrolytic cell, wherein, the positive input and function generator of potentiostat is connected, and reversely the input and output terminal of potentiostat is connected with electrolytic cell, to be made of the closed loop of negative-feedback amplification, output polarization electric current potentiostat and electrolytic cell；The negative input of IV conversion circuit connects electrolytic cell, the positive input ground connection of IV conversion circuit, the output terminal of IV conversion circuit is connected with follow-up reception signal acquisition circuit, polarization current for electrolytic cell to be exported in electrochemical reaction process is converted into voltage signal, so that follow-up reception signal acquisition circuit carries out data acquisition and processing (DAP).The utility model has higher stability and conversion accuracy under the control voltage of high speed；Current measurement high resolution, it is reproducible.
Description
Technical field
Potentiostat technical field is the utility model is related to, more particularly to a kind of high-precision reversely addition type potentiostat
And IV converted measurement circuits.
Background technology
Existing potentiostat circuit is there is stability is poor, conversion accuracy and resolution ratio are low, poor repeatability, anti-interference energy
The problems such as power is weak.
Utility model content
The purpose of this utility model is intended at least solve one of described technological deficiency.
For this reason, the purpose of this utility model is that propose that a kind of high-precision reversely addition type potentiostat and IV conversions are surveyed
Measure circuit.
To achieve these goals, the embodiment of the utility model provides a kind of high-precision reversely addition type potentiostat
And IV converted measurement circuits, including：Potentiostat, IV conversion circuit, electrolytic cell, wherein,
The positive input and function generator of the potentiostat is connected, the potentiostat it is reversely inputting and defeated
Outlet is connected with the electrolytic cell, defeated to be made of the closed loop of negative-feedback amplification the potentiostat and the electrolytic cell
Go out polarization current；
The negative input of the IV conversion circuit connects the electrolytic cell, and the positive input of the IV conversion circuit connects
Ground, the output terminal of the IV conversion circuit are connected with follow-up reception signal acquisition circuit, for by the electrolytic cell in electrification
Learn the polarization current that exports in reaction process and be converted into voltage signal, so that the follow-up reception signal acquisition circuit is into line number
According to collection and processing.
Further, the potentiostat and the IV conversion circuit use integrated operational amplifier.
Further, the potentiostat includes the first operational amplifier, is inputted with the negative sense of first operational amplifier
Hold first resistor, second resistance and the 3rd resistor being respectively connected with, the positive input ground connection of first operational amplifier, structure
Into reverse add circuit, which includes three branches, and the electric current of three branches is in the first operational amplifier
Reverse input end adduction, the sum of each electric current of inflow is zero.
Further, three branches include：
The first branch：The input terminal of first operational amplifier receives control voltage EOUT, through the first rheostat and institute
State the reverse input end that first resistor acts on first operational amplifier；
The second branch：The output terminal of second operational amplifier is connected with the 3rd resistor, forms voltage follower conduct
Backfeed loop is connected to reference electrode, and the feedback signal of the reference electrode current potential is through the second operational amplifier and the 3rd electricity
Resistance acts on the reverse input end of first operational amplifier；
3rd branch：External+5V a reference sources are linked into described by the second rheostat and the second resistance in circuit
The reverse input end of first operational amplifier, to return to zero to system.
Further, further include：First to the 3rd analog switch, first analog switch and first operational amplifier
Output terminal be connected with an electrode of the electrolytic cell, the forward direction of second analog switch and second operational amplifier
Input terminal is connected with another electrode of the electrolytic cell, the 3rd analog switch and the IV conversion circuit and the electrolysis
Another electrode in pond is connected, for by switch control potentiostat three electrode connecting ends and electrolytic cell conducting with
It is no.
Further, the IV conversion circuit uses feedback type electric flow measuring method, including the 3rd operational amplifier and the 4th
Operational amplifier, wherein, the 3rd operational amplifier forms current follower, output voltage homopolarity galvanic current with feedback resistance
Proportional, the polarization current signal that will be measured changes into voltage signal, by the four-operational amplifier, obtains and controls
Voltage parameters of the voltage EOUT with phase change.
Further, further include：Multiway analog switch, the multiway analog switch is connected with the feedback resistance, for selecting
Select the feedback resistance for switching different resistance values.
Further, to the power supply in reversely addition type potentiostat and the IV converted measurement circuits, digitally and mould
Intend isolated and separately connected up, including, by analog power, analog element and simulation with digital power, digital element and
Digitally carry out magnetic bead isolation.
According to high-precision reversely the addition type potentiostat and IV converted measurement circuits of the utility model embodiment, have
Following beneficial effect：
(1) under the control voltage of high speed, there is higher stability and conversion accuracy；
(2) current measurement high resolution, it is reproducible；
(3) good Anti-interference Design is provided, so as to ensure that the job stability of circuit.
The aspect and advantage that the utility model adds will be set forth in part in the description, partly by from following description
In become obvious, or recognized by the practice of the utility model.
Brief description of the drawings
The above-mentioned and/or additional aspect and advantage of the utility model will in the description from combination accompanying drawings below to embodiment
Become obvious and be readily appreciated that, wherein：
Fig. 1 is high-precision reversely addition type potentiostat and the IV converted measurement circuits according to the utility model embodiment
Schematic diagram；
Fig. 2 is the circuit diagram changed according to the potentiostat and its IV of the utility model embodiment；
Fig. 3 is the schematic diagram according to the sensitivity selection circuit of the utility model embodiment；
Fig. 4 is the Anti-interference Design schematic diagram according to the utility model embodiment；
Fig. 5 is the system block diagram according to the electro-chemical measuring apparatus of the utility model embodiment.
Embodiment
The embodiment of the utility model is described below in detail, the example of embodiment is shown in the drawings, wherein from beginning to end
Same or similar label represents same or similar element or has the function of same or like element.Below with reference to attached
The embodiment of figure description is exemplary, it is intended to for explaining the utility model, and it is not intended that limit to the utility model
System.
As shown in Figure 1, high-precision reversely the addition type potentiostat 100 and IV converted measurements of the utility model embodiment
Circuit, including：Potentiostat 100, IV conversion circuit 200, electrolytic cell 300.In one embodiment of the utility model, permanent electricity
Position device 100 and IV conversion circuit 200 use integrated operational amplifier.Function generator uses DA digital analog converters, receives letter
Number acquisition circuit uses AD analog-digital converters.
In general electrochemical reaction process, polarization current maximum magnitude is mA grades, and current measurement resolution ratio is less than 1nA.
Common operational amplifier all has mA grades of current output capability.To prevent the wave distortion of control voltage, to potentiostat
100 and IV conversion circuit 200 in the selection of amplifier, it is necessary to emphatically consider index be input offset voltage, input biased electrical
Stream and open-loop gain.Therefore, the integrated chip AD8627 used in the potentiostat 100 of the utility model, IV conversion circuit 200
And AD8608, for its input offset voltage at uV grades, input bias current is pA grades, and open-loop gain is more than 100Db, in coincident circuit
Requirement.
Preferably, potentiostat 100 selects the integrated operational amplifier chip of model AD8627；IV conversion circuit 200
Select the integrated operational amplifier chip of model AD8608.
Specifically, the positive input and function generator of potentiostat 100 is connected, the reverse input of potentiostat 100
And output terminal be connected with electrolytic cell 300, with by potentiostat 100 and electrolytic cell 300 formed negative-feedback amplification closed loop,
So that reference voltage changes with the adjusting of control voltage, and compared with the constant reference voltage of working electrode, obtain model
The scanning voltage of ± 2V changes is trapped among, finally realizes that polarization current exports.
Fig. 2 is the circuit diagram changed according to the potentiostat 100 and its IV of the utility model embodiment.Wherein, WE,
RE, CE represent working electrode, reference electrode and auxiliary electrode respectively, and polarization current i is cathodic reduction electric current, and provide cathode electricity
Flow for just.
As shown in Fig. 2, potentiostat 100 includes the first operational amplifier A 2, it is defeated with the negative sense of the first operational amplifier A 2
Enter first resistor R1, second resistance R2 and 3rd resistor R3 that end is respectively connected with, the positive input of the first operational amplifier A 2
Ground connection, forms reverse add circuit, which includes three branches, and the electric current of three branches is in the first operation amplifier
The sum of the reverse input end adduction of device A2, each electric current of inflow are zero.
Specifically, three branches include：
The first branch：The input terminal of first operational amplifier A 2 receives control voltage EOUT, through the first rheostat RW1 and the
One resistance R1 acts on the reverse input end of the first operation amplifier A2；
The second branch：The output terminal of second operational amplifier A 2 is connected with 3rd resistor R3, forms voltage follower conduct
Backfeed loop is connected to reference electrode.Since operational amplifier has high input impedance, do not had on reference electrode big
Electric current flows through, so as to avoid the interference to the electrode system surveyed.The feedback signal of reference electrode current potential is put through the second computing
Big device A1 and 3rd resistor R3 acts on the reverse input end of the first operational amplifier A 2.
3rd branch：External+5V a reference sources are linked into first by the second rheostat RW2 and second resistance R2 in circuit
The reverse input end of operational amplifier A 2, to return to zero to system.
Specifically, the bias current of amplifier, solution resistance can produce certain influence to control voltage in circuit, therefore,
External+5V a reference sources are linked into the reverse input end of A2 by rheostat RW2 and resistance R2 in circuit, so as to be carried out to system
Zeroing.In the circuit of this part, the in-phase input end+2.5V a reference sources of operational amplifier A 2 and A3, while be also work electricity
The constant potential point of pole.When input signal EOUT changes between 1V to 4V, the voltage change range of reference electrode for 4.5V~
0.5V, equivalent working electrode are -2V~2V relative to the potential change scope of reference electrode, thus meet scanning voltage ±
The design requirement changed between 2V.
With reference to figure 2, the negative input of IV conversion circuit 200 connects electrolytic cell 300, the positive input of IV conversion circuit 200
End ground connection, the output terminal of IV conversion circuit 200 is connected with follow-up reception signal acquisition circuit, for by electrolytic cell 300 in electricity
The polarization current exported in chemical reaction process is converted into voltage signal, so that follow-up reception signal acquisition circuit carries out data
Collection and processing.
Specifically, as shown in Fig. 2, IV conversion circuit 200 uses feedback type electric flow measuring method, including the 3rd operation amplifier
Device A3B and four-operational amplifier A3C, wherein, the 3rd operational amplifier A 3B and feedback resistance Rf forms current follower, defeated
Go out voltage same polarization current in proportion, the polarization current signal that will be measured changes into voltage signal, by the 4th operation amplifier
Device A3C, obtains the voltage parameter with phase change with control voltage EOUT.
Specifically, the electric current for flowing into working electrode is converted into voltage signal by IV conversion circuit 200, is turned for AD acquisition circuits
Change digital quantity into.The utility model uses feedback type electric flow measuring method, and the operational amplifier of selection is that inside has 4 amplifiers
Integrated chip AD8608, has used 2 tunnel therein amplifier in circuit, has been A3B and A3C respectively.By operational amplifier A 3B and instead
Feed resistance Rf constitutes current follower, the influence very little of the Low-bias Current of operational amplifier A D8608 to polarization current i, can
Ignore.Therefore the output voltage same polarization current in proportion of the 3rd operational amplifier A 3B, so that the polarization current letter that will be measured
Number voltage signal is changed into, by four-operational amplifier A3C, can obtain the voltage parameter with phase change with EOUT.Work as control
When voltage EOUT changes between 1V to 4V, the output voltage range for measuring the 3rd operational amplifier A 3B at this time is 5V-0V, warp
Output area is 0V-2.5V after reverse scaling circuit A3C, by the output electricity of AD acquisition circuit measuring operational amplifiers A3C
The measurement to polarization current and record can be achieved in pressure.
In electrochemical analysis test, polarization current size to be measured is often not under different electrochemical system test conditions
With, it is therefore desirable to user selects suitable sensitivity according to actual conditions, so as to ensure the accuracy of current detecting.For not
Same sensitivity can use different feedback resistance Rf.In one embodiment of the utility model, further include：Multi-channel analog
Switch, multiway analog switch are connected with feedback resistance, for selecting the feedback resistance of the different resistance values of switching.
Preferably, multiway analog switch selects model MAX4617.
Specifically, using switching of the multiway analog switch MAX4617 realizations to Rf, and in Rf both ends parallel filtering capacitance Cf
To form low-pass filter, schematic diagram is as shown in figure 3, the circuit of this part is linked into Fig. 2 with IWE and OWE endpoints, and is substituted
Rf and Cf circuits in Fig. 2.
In addition, as shown in Fig. 2, the utility model further includes：First to the 3rd analog switch, the first analog switch and first
The output terminal of operational amplifier is connected with an electrode of electrolytic cell 300, and the second analog switch and the second operational amplifier are just
It is connected to input terminal with another electrode of electrolytic cell 300, the 3rd analog switch and IV conversion circuit 200 and electrolytic cell 300
Another is connected at electrode, for controlling three electrode connecting ends of potentiostat 100 and the conducting of electrolytic cell 300 by switching
Whether.
Specifically, in order to control test process, also need to control three electrode connecting ends of potentiostat 100 by switching
Whether with the conducting of electrolytic cell 300.Realize that such function can be realized by analog switch, first in this circuit to
3rd analog switch is using low on-resistance, the DG419 of response quickly.As shown in Fig. 2, the first to the 3rd analog switch distinguishes Ei
D1, D2 and D3., can be in the external AD of output terminal of operational amplifier A 1 since operational amplifier has the output impedance of very little
Acquisition Circuit, is realized to the real-time measurement of scanning voltage and record.
The whole circuit of the utility model is made of the analog device of analog device and a part of Digital Signals, and
The anti-interference of analog device is poor, therefore when carrying out PCB design, with should carrying out power supply, the digitally isolation with simulation ground
With separated wiring, and isolated power supply.As shown in figure 5, to the electricity in reverse addition type potentiostat 100 and IV converted measurement circuits
Source, digitally isolated and separately connected up with simulation, including, by analog power, analog element and simulation with numeral
Power supply, digital element and digitally progress magnetic bead isolation, realize Anti-interference Design.
As shown in figure 5, the electro-chemical measuring apparatus of the utility model embodiment, including：Function generator 2, above-mentioned implementation
Reverse addition type potentiostat and IV converted measurements circuit 1, reception signal acquisition circuit 3 and the microcontroller 4 that example provides.
Specifically, the input terminal of function generator 2 is connected with microcontroller 4, the output terminal and high accuracy of function generator 2
The input terminal of reverse addition type potentiostat and IV converted measurements circuit 1 be connected, for control voltage needed for producing.High accuracy
The output terminal of reverse addition type potentiostat and IV converted measurements circuit 1 be connected with receiving signal acquisition circuit 3, for basis
Control voltage to perform the control and measurement of signal, the polarization current exported in electrochemical reaction process is converted into voltage signal.
The output terminal for receiving signal acquisition circuit 3 is connected with microcontroller, for receiving the signal after measuring.Microcontroller 4 is mainly adopted
By the use of Embedded microprocessor as master controller, the work(such as realization automatically controls, data acquisition, data processing, display and transmission
Energy.
In one embodiment of the utility model, function generator 2 uses DA digital analog converters, receives signal acquisition and returns
Road 3 uses AD analog-digital converters.
According to high-precision reversely the addition type potentiostat and IV converted measurement circuits of the utility model embodiment, have
Following beneficial effect：
(1) under the control voltage of high speed, there is higher stability and conversion accuracy；
(2) current measurement high resolution, it is reproducible；
(3) good Anti-interference Design is provided, so as to ensure that the job stability of circuit.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or the spy for combining the embodiment or example description
Point is contained at least one embodiment or example of the utility model.In the present specification, to the schematic table of above-mentioned term
State and may not refer to the same embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be
Combined in an appropriate manner in any one or more embodiments or example.
Although the embodiment of the utility model has been shown and described above, it is to be understood that above-described embodiment is
Exemplary, it is impossible to the limitation to the utility model is interpreted as, those of ordinary skill in the art are not departing from the utility model
Principle and objective in the case of above-described embodiment can be changed in the scope of the utility model, change, replace and
Modification.The scope of the utility model is by appended claims and its equivalent limits.
Claims (8)
1. a kind of high-precision reversely addition type potentiostat and IV converted measurement circuits, it is characterised in that including：Constant potential
Device, IV conversion circuit, electrolytic cell, wherein,
The positive input and function generator of the potentiostat is connected, reversely the input and output terminal of the potentiostat
It is connected with the electrolytic cell, to be made of the closed loop of negative-feedback amplification, output stage the potentiostat and the electrolytic cell
Galvanic current；
The negative input of the IV conversion circuit meets the electrolytic cell, the positive input ground connection of the IV conversion circuit, institute
The output terminal for stating IV conversion circuit is connected with follow-up reception signal acquisition circuit, for by the electrolytic cell in electrochemical reaction
During the polarization current that exports be converted into voltage signal, so that the follow-up reception signal acquisition circuit carries out data acquisition
And processing.
2. high-precision reversely addition type potentiostat and IV converted measurement circuits as claimed in claim 1, it is characterised in that
The potentiostat and the IV conversion circuit use integrated operational amplifier.
3. high-precision reversely addition type potentiostat and IV converted measurement circuits as claimed in claim 1, it is characterised in that
The potentiostat includes the first operational amplifier, first be respectively connected with the negative input of first operational amplifier
Resistance, second resistance and 3rd resistor, the positive input ground connection of first operational amplifier, form reverse add circuit,
The reverse add circuit includes three branches, and the electric current of three branches adds in the reverse input end of the first operational amplifier
With the sum of each electric current of inflow is zero.
4. high-precision reversely addition type potentiostat and IV converted measurement circuits as claimed in claim 3, it is characterised in that
Three branches include：
The first branch：The input terminal of first operational amplifier receives control voltage EOUT, through the first rheostat and described the
One resistance acts on the reverse input end of first operational amplifier；
The second branch：The output terminal of second operational amplifier is connected with the 3rd resistor, forms voltage follower as feedback
Circuit is connected to reference electrode, and the feedback signal of the reference electrode current potential is made through the second operational amplifier and the 3rd resistor
Reverse input end for first operational amplifier；
3rd branch：External+5V a reference sources are linked into described first by the second rheostat and the second resistance in circuit
The reverse input end of operational amplifier, to return to zero to system.
5. high-precision reversely addition type potentiostat and IV converted measurement circuits as claimed in claim 4, it is characterised in that
Further include：First to the 3rd analog switch, the output terminal of first analog switch and first operational amplifier and described
One electrode of electrolytic cell is connected, positive input and the electricity of second analog switch with second operational amplifier
Another electrode of Xie Chi is connected, the 3rd analog switch and the IV conversion circuit and another electrode of the electrolytic cell
It is connected, whether for by switching the conducting come three electrode connecting ends controlling potentiostat and electrolytic cell.
6. high-precision reversely addition type potentiostat and IV converted measurement circuits as claimed in claim 1, it is characterised in that
The IV conversion circuit uses feedback type electric flow measuring method, including the 3rd operational amplifier and four-operational amplifier, wherein,
3rd operational amplifier forms current follower with feedback resistance, and output voltage same polarization current in proportion, will measure
Polarization current signal change into voltage signal, by the four-operational amplifier, obtain and the control same phase transformations of voltage EOUT
The voltage parameter of change.
7. high-precision reversely addition type potentiostat and IV converted measurement circuits as claimed in claim 6, it is characterised in that
Further include：Multiway analog switch, the multiway analog switch are connected with the feedback resistance, for selecting to switch different resistance values
Feedback resistance.
8. high-precision reversely addition type potentiostat and IV converted measurement circuits as claimed in claim 1, it is characterised in that
To the power supply in the reversely addition type potentiostat and IV converted measurement circuits, digitally isolated and divided with simulation
Open wiring, including, by analog power, analog element and simulation with digital power, digital element and digitally carry out magnetic bead every
From.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721052693.4U CN207263686U (en) | 2017-08-22 | 2017-08-22 | A kind of high-precision reversely addition type potentiostat and IV converted measurement circuits |
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| CN201721052693.4U CN207263686U (en) | 2017-08-22 | 2017-08-22 | A kind of high-precision reversely addition type potentiostat and IV converted measurement circuits |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107688048A (en) * | 2017-08-22 | 2018-02-13 | 中国检验检疫科学研究院 | Reverse addition type potentiostat and IV converted measurement circuit available for electrochemical measurement |
| CN111220778A (en) * | 2020-03-02 | 2020-06-02 | 北京市华云分析仪器研究所有限公司 | Signal processing circuit of carbon monoxide analyzer |
| CN111693582A (en) * | 2020-05-26 | 2020-09-22 | 杭州电子科技大学 | Portable front end device of electrochemistry detection high accuracy |
-
2017
- 2017-08-22 CN CN201721052693.4U patent/CN207263686U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107688048A (en) * | 2017-08-22 | 2018-02-13 | 中国检验检疫科学研究院 | Reverse addition type potentiostat and IV converted measurement circuit available for electrochemical measurement |
| CN111220778A (en) * | 2020-03-02 | 2020-06-02 | 北京市华云分析仪器研究所有限公司 | Signal processing circuit of carbon monoxide analyzer |
| CN111693582A (en) * | 2020-05-26 | 2020-09-22 | 杭州电子科技大学 | Portable front end device of electrochemistry detection high accuracy |
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