CN100466474C - Voltage-current conversion circuit device - Google Patents
Voltage-current conversion circuit device Download PDFInfo
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- CN100466474C CN100466474C CNB2006101509349A CN200610150934A CN100466474C CN 100466474 C CN100466474 C CN 100466474C CN B2006101509349 A CNB2006101509349 A CN B2006101509349A CN 200610150934 A CN200610150934 A CN 200610150934A CN 100466474 C CN100466474 C CN 100466474C
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- reference resistance
- operational amplifier
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- differential amplifier
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Abstract
This invention relates to a conversion circuit device from voltage to current including an operational amplifier U1, a transistor Q, a reference resistor R1, a load resistor R2 and a supply E characterizing in also including a differential amplifier U2, in which, the positive and negative input ends of the operational amplifier are connected with one end of an input voltage and the output end of the differential amplifier, the output of the operational amplifier is connected with the control electrode of the transistor, the input end K3 of the amplifier is connected with the reference resistor, K4 is connected to the earth, one end of a serial circuit composed of the load R2, transistor Q and the reference resistor R1 is connected with the supply and the other end is connected to the earth.
Description
(1) technical field
The present invention relates to a kind of circuit arrangement, particularly a kind of voltage-current conversion circuit device.
(2) technical background
At in the past voltage to the conversion circuit device of electric current.For example number of patent application is 02226030.7, and name is called " a kind of voltage "; Number of patent application is 96191240.5, name is called in the patent document of " current/charge-voltage convertor device " disclosed voltage-current conversion circuit device and mainly is made up of operational amplifier U1, transistor Q and reference resistance R1, it is its basic structure that Fig. 1 gives: the source follow circuit that the end of transistor Q and the cascaded structure of reference resistance R1 are formed, the other end of power supply E and load R2 and transistor Q is in series, and the output of operational amplifier links to each other with transistorized control electrode.Electric current through overload R2 equates basically with the electric current of process reference resistance R1.At the duration of work of circuit, the output of operational amplifier makes the current potential of the control electrode of transistor Q remain on such level so that the signal of the inverting input of operational amplifier is substantially equal to the signal of operational amplifier in-phase input end.Thereby reach the relation that meets V=V1=R1 * I basically.Here, V is an input voltage, and R1 is the resistance value of reference resistance, and I is the electric current by reference resistance, and V1 is the reference voltage that the electric current I by reference resistance R1 produces on reference resistance R1.
Adopt the current/charge-voltage convertor of Fig. 1 or similar principles, there are the following problems, because reference resistance R1 is bigger, when the electric current I that produces when needs was big, the power consumption P that electric current I produces on reference resistance R1 can increase along with the increase of electric current; Because reference resistance R1 is bigger, the reference voltage V1 that produces on the reference resistance influences the response range of load R2; In the circuit real work, because the instability on power supply ground, or existence than the distributed constant of growing that is connected lead is arranged between reference resistance R1 earth terminal and power supply ground, interference signal can occur, interference signal can appear in the electric current of generation, influences the precision of output current.
(3) summary of the invention
The object of the present invention is to provide a kind of voltage-current conversion circuit device with stronger antijamming capability.
The object of the present invention is achieved like this: it comprises operational amplifier U1, transistor Q, reference resistance R1, load resistance R2, power supply E, it also comprises differential amplifier U2, and the positive of operational amplifier U1 and inverting input are connected the output of input voltage V and differential amplifier U2 respectively in this circuit; The output of operational amplifier U1 links to each other with the control electrode of transistor Q; The first input end K3 of differential amplifier U2 links to each other with reference resistance R1; Two other electrode except that control electrode of transistor Q is composed in series series circuit with load resistance R2, reference resistance R1 respectively, the other end of load resistance R2 links to each other with power supply E, and the other end of reference resistance R1 is connected back ground connection with the second input K4 of differential amplifier U2.
In the time of circuit working, the signal of the output of operational amplifier U1 remains on the level that the signal of the homophase that makes operational amplifier and inverting input equates basically, thereby reach the relation that meets V=G * R1 * I basically, be substantially equal to V/ (G * R1), wherein G is an operational amplifier open loop gain amplifier so that flow through the electric current of load R2.
Ifs circuit during operation, interference signal appears in the earth terminal of the series circuit of forming at transistor Q and reference resistance R1, then interference signal can cause the change of reference resistance both end voltage, because differential amplifier has the difference amplifying power, above-mentioned interference signal can not appear at the output of differential amplifier.Therefore, disturbing appears in the electric current of voltage-current conversion circuit device generation hardly.
Can obtain some favourable results according to this voltage-current conversion circuit device, operational amplifier wherein is relative simple and cheap amplifier with differential amplifier.
Be noted that load R2, any tandem compound of transistor Q and reference resistance R1 or arrange again etc. all is effectively, and is comprised by embodiment of the present invention.
Found can further reduce to disturb when the output of operational amplifier and inverting input insert electric capacity, at this, capacitive means is as the filter of high-frequency interferencing signal.
Found can further reduce to disturb when reference resistance is in parallel with capacitive means, at this, capacitive means is as the filter of high-frequency interferencing signal.
Found that the circuit that differential amplifier can be made up of some general-purpose operation amplifiers realizes, also can realize by operational amplifier with difference enlarging function.
The electric current that this voltage-current conversion circuit device generates has stronger antijamming capability.Be applicable to that voltage to current transfer device generates the size of electric current and the situation that is in proportion and changes of input voltage, is particularly useful for the bigger situation of electric current that voltage generates to current transfer device.
(4) description of drawings
Fig. 1 is the schematic diagram of voltage-current conversion circuit device in the past.
Fig. 2 is a basic circuit schematic diagram of the present invention.
Fig. 3 is the circuit theory diagrams of adding capacitor C 1 of the present invention.
Fig. 4 is the circuit theory diagrams that the present invention adds capacitor C 2.
Fig. 5 is the circuit theory diagrams that the present invention adds capacitor C 1 and C2.
(5) embodiment
The present invention is described further below in conjunction with accompanying drawing:
In conjunction with Fig. 2, the positive of operational amplifier U1 is connected input voltage V one end and differential amplifier U2 output respectively with inverting input; The output of operational amplifier U1 links to each other with transistorized control electrode; The input K3 of differential amplifier U2 links to each other with reference resistance R1; Input K4 ground connection.Load R2, transistor Q, series circuit one end that reference resistance R1 forms links to each other other end ground connection with power supply.
When circuit working, voltage signal V is imported by the operational amplifier in-phase input end, according to two inputs of operational amplifier " empty short " and input input current is zero principle, and the voltage of inverting input will equal the voltage of in-phase input end, i.e. input signal V.Like this, flow through voltage that the electric current I of reference resistance R1 produces through differential amplifier U2 amplify G doubly after, the output voltage of differential amplifier equates with input signal V is approaching.Because electric current I flows through load R2 and field-effect transistor Q and reference resistance R1, be V/ (G * R1) so flow through the electric current of load R2 and the pass between the input voltage.
This device is compared with known voltage to current converter circuit device, be depressed under the electric current corresponding relation situation in same electrical, this device reference resistance R1 and known voltage to current converter circuit device resistance reduces G doubly, the then corresponding power consumption that produces on reference resistance reduces G doubly, and the voltage difference that produces on reference resistance reduces G doubly.If during circuit working, interference signal appears and the reference resistance earth terminal that is added to, because differential amplifier only amplifies the voltage differential signal at reference resistance two ends,, can not influence the current conversion of circuit then in the interference of reference resistance earth terminal existence.
In conjunction with Fig. 3, the positive of operational amplifier U1 is connected input voltage V one end and differential amplifier U2 output and capacitor C 1 one ends respectively with inverting input; The output of operational amplifier U1 links to each other with capacitor C 1 other end with transistorized control electrode; The input K3 of differential amplifier U2 links to each other with reference resistance R1; Input K4 ground connection.Load R2, transistor Q, series circuit one end that reference resistance R1 forms links to each other other end ground connection with power supply.
This circuit arrangement is compared with voltage-current conversion circuit device shown in Figure 2, and the output of operational amplifier U1 links to each other with capacitor C 1 with inverting input, and capacitor C 1 can further reduce to disturb as the filter of high-frequency interferencing signal.
In conjunction with Fig. 4, the positive of operational amplifier U1 is connected input voltage V one end and differential amplifier U2 output respectively with inverting input; The output of operational amplifier U1 links to each other with transistorized control electrode; The input K3 of differential amplifier U2 and K4 are connected the two ends of the parallel circuits that R1 and capacitor C 2 form respectively.Input K4 ground connection.Load R2, series circuit one end that transistor Q forms links to each other with power supply, and the other end links to each other with the parallel circuits that resistance R 1 and capacitor C 1 are formed.
This circuit arrangement is compared with Fig. 2 circuit arrangement, and reference resistance R1 and capacitor C 2 parallel connections at the filter of this capacitor C 2 as high-frequency interferencing signal, can further reduce to disturb.
In conjunction with Fig. 5, the positive of operational amplifier U1 is connected input voltage V one end and differential amplifier U2 output and capacitor C 1 one ends respectively with inverting input; The output of operational amplifier U1 links to each other with capacitor C 1 other end with transistorized control electrode; The input K3 of differential amplifier U2 and K4 are connected the two ends of the parallel circuits that R1 and capacitor C 2 form respectively.Input K4 ground connection.Load R2, series circuit one end that transistor Q forms links to each other with power supply, and the other end links to each other with the parallel circuits that resistance R 1 and capacitor C 1 are formed.
This circuit arrangement is compared with Fig. 2, Fig. 3, Fig. 4 circuit arrangement, and the output of operational amplifier U1 links to each other with capacitor C 1 with inverting input, and capacitor C 1 can further reduce to disturb as the filter of high-frequency interferencing signal.Reference resistance R1 and capacitor C 2 parallel connections at the filter of this capacitor C 2 as high-frequency interferencing signal, can further reduce to disturb.
Claims (5)
1. voltage-current conversion circuit device, it comprises: operational amplifier (U1), transistor (Q), reference resistance (R1), load resistance (R2), power supply (E) it is characterized in that: further comprising differential amplifier (U2), and the positive of operational amplifier in this circuit (U1) and inverting input are connected the output of input voltage (V) and differential amplifier (U2) respectively; The output of operational amplifier (U1) links to each other with the control electrode of transistor (Q); The first input end (K3) of differential amplifier (U2) links to each other with reference resistance (R1); Two other electrode except that control electrode of transistor (Q) is composed in series series circuit with load resistance (R2), reference resistance (R1) respectively, the other end of load resistance (R2) links to each other with power supply (E), and the other end of reference resistance (R1) is connected back ground connection with second input (K4) of differential amplifier (U2).
2. voltage-current conversion circuit device according to claim 1 is characterized in that: described differential amplifier (U2) is to have the differential amplifier that multiplication factor is G.
3. voltage-current conversion circuit device according to claim 1 and 2 is characterized in that: the output of operational amplifier (U1) and inverting input are connected with first electric capacity (C1).
4. according to claim 1 or 2 described voltage-current conversion circuit devices, it is characterized in that: reference resistance (R1) is in parallel with second electric capacity (C2).
5. according to the described voltage-current conversion circuit device of claim 3, it is characterized in that: reference resistance (R1) is in parallel with second electric capacity (C2).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006101509349A CN100466474C (en) | 2006-10-25 | 2006-10-25 | Voltage-current conversion circuit device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006101509349A CN100466474C (en) | 2006-10-25 | 2006-10-25 | Voltage-current conversion circuit device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1945973A CN1945973A (en) | 2007-04-11 |
| CN100466474C true CN100466474C (en) | 2009-03-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006101509349A Expired - Fee Related CN100466474C (en) | 2006-10-25 | 2006-10-25 | Voltage-current conversion circuit device |
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| CN (1) | CN100466474C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101551938B (en) * | 2008-12-30 | 2010-12-01 | 上海科达机电控制有限公司 | Voltage-current transformation method |
| CN102035546A (en) * | 2010-12-04 | 2011-04-27 | 中国北车股份有限公司大连电力牵引研发中心 | Voltage current transformer |
| CN102394494A (en) * | 2011-09-28 | 2012-03-28 | 魏德米勒电联接国际贸易(上海)有限公司 | Current-voltage converting circuit provided with over-current protection circuit module |
| 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 |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5642064A (en) * | 1993-12-29 | 1997-06-24 | Matsushita Electric Industrial Co., Ltd. | Voltage to current conversion circuit including a differential amplifier |
| CN1166245A (en) * | 1995-08-29 | 1997-11-26 | 菲利浦电子有限公司 | Circuit arrangement provided with a voltage-current converter |
| CN2524430Y (en) * | 2002-03-01 | 2002-12-04 | 顺德市华傲电子有限公司 | Voltage/current conversion circuit |
| JP2005012581A (en) * | 2003-06-20 | 2005-01-13 | Renesas Technology Corp | Voltage current converter circuit and pll circuit using the same |
-
2006
- 2006-10-25 CN CNB2006101509349A patent/CN100466474C/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5642064A (en) * | 1993-12-29 | 1997-06-24 | Matsushita Electric Industrial Co., Ltd. | Voltage to current conversion circuit including a differential amplifier |
| CN1166245A (en) * | 1995-08-29 | 1997-11-26 | 菲利浦电子有限公司 | Circuit arrangement provided with a voltage-current converter |
| CN2524430Y (en) * | 2002-03-01 | 2002-12-04 | 顺德市华傲电子有限公司 | Voltage/current conversion circuit |
| JP2005012581A (en) * | 2003-06-20 | 2005-01-13 | Renesas Technology Corp | Voltage current converter circuit and pll circuit using the same |
Non-Patent Citations (2)
| Title |
|---|
| 数字V/I转换器. 许红玉，李斌.自动化仪表，第22卷第9期. 2001 |
| 数字V/I转换器. 许红玉，李斌.自动化仪表，第22卷第9期. 2001 * |
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| CN1945973A (en) | 2007-04-11 |
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Granted publication date: 20090304 Termination date: 20121025 |