CN202563365U - Voltage-current switch circuit - Google Patents
Voltage-current switch circuit Download PDFInfo
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- CN202563365U CN202563365U CN2011203654451U CN201120365445U CN202563365U CN 202563365 U CN202563365 U CN 202563365U CN 2011203654451 U CN2011203654451 U CN 2011203654451U CN 201120365445 U CN201120365445 U CN 201120365445U CN 202563365 U CN202563365 U CN 202563365U
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Abstract
A voltage-current switch circuit comprises a voltage (Ui) to be switched, an output current (Iout), a resistor (R3) and operational amplifiers (U1, U2) connected between the resistor (R3) and the output current (Iout). The voltage-current switch circuit further comprises an output current adjusting circuit which comprises two operational amplifiers (U3, U4), resistors (R5, R6) and a potentiometer (Rp). The potentiometer (Rp) is connected between the anode (+VCC) of a working power supply and the cathode (-VCC) of the working power supply through the resistors (R5, R6). The slide end of the potentiometer (Rp) is connected with the non-inverting input end (IN+) of the operational amplifier (U3). The voltage (Ui) to be switched is connected with the non-inverting input end (IN+) of the operational amplifier (U4). The output end (Uo4) of the operational amplifier (U4) is connected to the resistor (R3). The output current of the switch circuit can be adjusted within a small range by adjusting the potentiometer in the circuit. A high-precision voltage-current switch is then achieved.
Description
Technical field
The utility model relates to a kind of current output circuit, the current/charge-voltage convertor in especially a kind of current output circuit.
Background technology
In various fields such as production practices and scientific research; Often need the voltage signal that the front equipment end circuit collects be converted into 0～20mA or 4～20mA current signal of standard; Then through signal wire transmits to late-class circuit module or other demonstrations, opertaing device, to realize purposes such as signal condition, mechanism's driving.
Shown in Figure 1 is current/charge-voltage convertor commonly used at present.Ui is an input voltage to be converted, and Iout is the output current after changing.
Wherein: U1, U2 have all introduced the circuit negative feedback, and U1 constitutes the homophase summing circuit, and U2 constitutes voltage follower, gets R1=R2=R3=R4=R.
Uo2＝Up2
Up1＝R4/(R3+R4)Ui+R3/(R3+R4)Up2＝0.5Ui+0.5Up2
Uo1＝(1+R2/R1)Up1＝2Up1
Can get: Uo1=Ui+Up2
The last voltage of Ro is: URo=Uo1-Up2=Ui
So: Iout=Ui/Ro
It is thus clear that: in theory, the numerical value of output current Iout only depends on the ratio of input voltage Ui and resistance R o.But when circuit moved, because the influence of the extraneous factors such as trueness error of the difference of actual working environment and components and parts causes under the situation of identical input voltage, output current will produce deviation to a certain degree.This situation is inapplicable for the occasion of the high-precision voltage-to-current conversion of signals of needs.Therefore, be necessary foregoing circuit is improved, make it to improve the precision of output current, promptly current output value and theoretical value match basically.
Summary of the invention
The purpose of the utility model is to overcome the deficiency of prior art, proposes a kind of improved current/charge-voltage convertor, and it can improve the electric current output accuracy.
For realizing above-mentioned purpose; The utility model proposes following technical scheme: a kind of current/charge-voltage convertor; Comprise voltage U i to be converted, output current Iout, resistance R 3 and be connected resistance R 3 and output current Iout between operational amplifier U1 and operational amplifier U2; It is characterized in that: said current/charge-voltage convertor also comprises the output current regulating circuit; Said output current regulating circuit comprises two operational amplifier U3, U4, resistance R 5, R6 and potentiometer Rp, wherein potentiometer Rp through resistance R 5 and R6 be connected circuit positive and negative working power+VCC ,-VCC between, the sliding end of potentiometer Rp links to each other with the in-phase input end IN+ of operational amplifier U3; Voltage U i to be converted links to each other with the in-phase input end IN+ of operational amplifier U4, and the output terminal Uo4 of operational amplifier U4 is connected to resistance R 3.
Preferably, said resistance R 5 is connected between the upper end of positive working power+VCC and said potentiometer Rp of circuit.
Preferably, said resistance R 6 is connected between the lower end of negative working power-VCC and said potentiometer Rp of circuit.
Preferably, said output current regulating circuit also comprises resistance R 7, and the inverting input IN-of said operational amplifier U3 is with after its output terminal OUT is connected, and the left end with said resistance R 7 links to each other again.
Preferably; Said output current regulating circuit also comprises resistance R 8; The inverting input IN-of said operational amplifier U4 is connected between the left end of right-hand member and resistance R 8 of resistance R 7, and the output terminal OUT of said operational amplifier U4 is connected with the right-hand member of resistance R 8, the left end of resistance R 3.
Preferably, said output current regulating circuit also comprises resistance R 9, and said resistance R 9 is connected between the in-phase input end IN+ of voltage U i to be converted and said operational amplifier U4.
Preferably, said output current regulating circuit also comprises resistance R 10, and the left end of said resistance R 10 links to each other with the right-hand member of said resistance R 9, and its right-hand member ground connection.
Compared with prior art; The utility model provides a kind of current/charge-voltage convertor that comprises the output current regulating circuit; It is through the potentiometer in the regulating circuit; The output current Iout of change-over circuit is adjusted among a small circle, thereby can remedy because the output current deviation that the external factor such as error of the difference of working environment, components and parts cause realizes high-precision voltage-to-current conversion.
Description of drawings
Fig. 1 current/charge-voltage convertor structural drawing of the prior art.
The current/charge-voltage convertor structural drawing of Fig. 2 the utility model.
Embodiment
The accompanying drawing that will combine the utility model below carries out clear, complete description to technical scheme among the utility model embodiment.
With reference to Fig. 2; Current/charge-voltage convertor corresponding to the utility model most preferred embodiment is on the basis of the current/charge-voltage convertor commonly used at present described in the background technology of this patent file, to have added the output current regulating circuit; This output current regulating circuit is positioned at frame of broken lines; It is by operational amplifier U3, U4, and resistance R 5～R10 and potentiometer Rp form.+ VCC and-VCC are respectively the positive and negative working power of circuit.The upper end of resistance R 5 is connected with the positive working power+VCC of circuit, and its lower end is connected with the upper end of potentiometer Rp; The lower end of resistance R 6 is connected with the negative working power-VCC of circuit, and its upper end is connected with the lower end of potentiometer Rp.The in-phase input end of operational amplifier U3 " IN+ " links to each other with the sliding end of Rp, and its inverting input " IN-" is with after its output terminal " OUT " is connected, and the left end with resistance R 7 links to each other again.The left end of resistance R 9 is connected with input voltage Ui, and its right-hand member is connected with the in-phase input end " IN+ " of operational amplifier U4 and the left end of resistance R 10, resistance R 10 right-hand members with " " be connected.The inverting input of operational amplifier U4 " IN-" is connected with the right-hand member of resistance R 7, the left end of resistance R 8; Its output terminal " OUT " is connected with the right-hand member of resistance R 8, the left end of resistance R 3; Deliver to late-class circuit through resistance R 3 input voltage of inching and carry out the voltage-to-current conversion; This late-class circuit is the voltage-circuit conversion circuit commonly used at present described in the background technology, repeats no more at this.
It is thus clear that operational amplifier U3 and resistance R 5, R6 and steady arm Rp form the adjustable follower circuit of input voltage Uadj, Uadj is the magnitude of voltage that takes out on the sliding end of potentiometer Rp; The output voltage of operational amplifier U3 is Uo3, equates with Uadj homophase and numerical value.Operational amplifier U4 and resistance R 7～R10 form differential amplifier, and its input is respectively the output voltage U o3 of operational amplifier U3 and input voltage Ui to be converted, and output voltage is Uo4.
Uo4＝Ui(1+R8/R7)(R10/(R9+R10))-Uo3(R8/R7)；
Choose R7=R8=R9=R10, can get: Uo4=Ui-Uo3;
Uo4 described in its principle of work such as the background technology, can get: output current Iout=Uo4/Ro as the input voltage of back level common voltage-current converter circuit.
When real work, at first regulate the sliding end of steady arm Rp, making Uadj is zero.Input voltage Ui carries out the conversion of voltage-to-current then.Measure the real output value of output current Iout at circuit output end; If when the numerical value of output current Iout and ideal value generation deviation; Can be through the sliding end of regulator potentiometer Rp, the input voltage Uadj that changes operational amplifier U3 is its output voltage U o3, and then changes Uo4; The output valve of adjustment Iout is consistent with ideal value, thereby has improved the output accuracy of switching current.
Uadj is that the range of adjustment of Uo3 is:
Uo3(min)＝VCC-(2VCC/(R5+Rp+R6))*(R5+Rp)；
Uo3(max)＝VCC-(2VCC/(R5+Rp+R6))*R5；
Usually, choose the resistance of suitable resistance R 5, R6, Rp, the Current Regulation scope that makes output current Iout-1mA～+ 1mA between.
Visible through foregoing description; The utility model provides a kind of circuit that can improve voltage-to-current when conversion electric current output accuracy; It is through the potentiometer Rp in the regulating circuit; The output current Iout of change-over circuit is adjusted among a small circle, thereby can remedy because the output current deviation that the external factor such as error of the difference of working environment, components and parts cause realizes high-precision voltage-to-current conversion.And the current/charge-voltage convertor of the utility model is simple and practical, and is easy to adjust, and working stability has good practical function.
Though; Technology contents of the utility model and technical characterictic have disclosed as above; Yet those of ordinary skill in the art still maybe be based on the teaching of the utility model and announcements and are done all replacement and modifications that does not deviate from the utility model spirit, and therefore, the utility model protection domain should be not limited to the content that embodiment discloses; And should comprise various replacement and the modifications that do not deviate from the utility model, and contained by the present patent application claim.
Claims (7)
1. current/charge-voltage convertor; Comprise voltage U i to be converted, output current Iout, resistance R 3 and be connected resistance R 3 and output current Iout between operational amplifier U1 and operational amplifier U2; It is characterized in that: said current/charge-voltage convertor also comprises the output current regulating circuit; Said output current regulating circuit comprises two operational amplifier U3, U4, resistance R 5, R6 and potentiometer Rp; Wherein potentiometer Rp through resistance R 5 and R6 be connected circuit positive and negative working power+VCC ,-VCC between; The sliding end of potentiometer Rp links to each other with the in-phase input end IN+ of operational amplifier U3, and voltage U i to be converted links to each other with the in-phase input end IN+ of operational amplifier U4, and the output terminal Uo4 of operational amplifier U4 is connected to resistance R 3.
2. current/charge-voltage convertor according to claim 1 is characterized in that: said resistance R 5 is connected between the upper end of positive working power+VCC and said potentiometer Rp of circuit.
3. current/charge-voltage convertor according to claim 1 and 2 is characterized in that: said resistance R 6 is connected between the lower end of negative working power-VCC and said potentiometer Rp of circuit.
4. current/charge-voltage convertor according to claim 1; It is characterized in that: said output current regulating circuit also comprises resistance R 7; The inverting input IN-of said operational amplifier U3 is with after its output terminal OUT is connected, and the left end with said resistance R 7 links to each other again.
5. current/charge-voltage convertor according to claim 1; It is characterized in that: said output current regulating circuit also comprises resistance R 8; The inverting input IN-of said operational amplifier U4 is connected between the left end of right-hand member and resistance R 8 of resistance R 7, and the output terminal OUT of said operational amplifier U4 is connected with the right-hand member of resistance R 8, the left end of resistance R 3.
6. current/charge-voltage convertor according to claim 1 is characterized in that: said output current regulating circuit also comprises resistance R 9, and said resistance R 9 is connected between the in-phase input end IN+ of voltage U i to be converted and said operational amplifier U4.
7. current/charge-voltage convertor according to claim 6 is characterized in that: said output current regulating circuit also comprises resistance R 10, and the left end of said resistance R 10 links to each other with the right-hand member of said resistance R 9, and its right-hand member ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203654451U CN202563365U (en) | 2011-09-28 | 2011-09-28 | Voltage-current switch circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203654451U CN202563365U (en) | 2011-09-28 | 2011-09-28 | Voltage-current switch circuit |
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| CN202563365U true CN202563365U (en) | 2012-11-28 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN2011203654451U Expired - Fee Related CN202563365U (en) | 2011-09-28 | 2011-09-28 | Voltage-current switch circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102393775A (en) * | 2011-09-28 | 2012-03-28 | 魏德米勒电联接国际贸易(上海)有限公司 | Voltage-current converting circuit |
| CN104064020A (en) * | 2014-07-02 | 2014-09-24 | 北京机械设备研究所 | Voltage and current signal conversion circuit |
| CN104320123A (en) * | 2014-10-13 | 2015-01-28 | 无锡信大气象传感网科技有限公司 | 4-20 mA current conversion circuit |
| CN109814647A (en) * | 2018-12-27 | 2019-05-28 | 湖南银河电气有限公司 | A kind of wide-range and the ac current source and processing method of closed-loop control |
-
2011
- 2011-09-28 CN CN2011203654451U patent/CN202563365U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102393775A (en) * | 2011-09-28 | 2012-03-28 | 魏德米勒电联接国际贸易(上海)有限公司 | Voltage-current converting circuit |
| CN104064020A (en) * | 2014-07-02 | 2014-09-24 | 北京机械设备研究所 | Voltage and current signal conversion circuit |
| CN104320123A (en) * | 2014-10-13 | 2015-01-28 | 无锡信大气象传感网科技有限公司 | 4-20 mA current conversion circuit |
| CN104320123B (en) * | 2014-10-13 | 2017-10-13 | 无锡信大气象传感网科技有限公司 | A kind of 4 20mA current converter circuits |
| CN109814647A (en) * | 2018-12-27 | 2019-05-28 | 湖南银河电气有限公司 | A kind of wide-range and the ac current source and processing method of closed-loop control |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20121128 Termination date: 20190928 |
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| CF01 | Termination of patent right due to non-payment of annual fee |