CN201839193U - Voltage and current conversion circuit - Google Patents
Voltage and current conversion circuit Download PDFInfo
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- CN201839193U CN201839193U CN2010205903168U CN201020590316U CN201839193U CN 201839193 U CN201839193 U CN 201839193U CN 2010205903168 U CN2010205903168 U CN 2010205903168U CN 201020590316 U CN201020590316 U CN 201020590316U CN 201839193 U CN201839193 U CN 201839193U
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Abstract
The utility model provides a voltage and current conversion circuit, which comprises an operational amplifier, a first current branch and a second current branch. The operational amplifier is a double-input and double-output amplifier, wherein two output ends of the operational amplifier respectively control common-gate transistors of the first current branch and the second current branch. When input voltage varies, the two output ends of the double-output operational amplifier can make response simultaneously nearly; and when input voltage and output current vary within a wider range, stable and reliable operation of the voltage and current conversion circuit can be guaranteed.
Description
[technical field]
The utility model relates to electronic circuit field, particularly about a kind of voltage-current converter circuit.
[background technology]
In many application, need voltage signal is converted to current signal, in for example various switching mode DC-to-DC electric pressure converters or the AC-DC electric pressure converter, all need the electric current of switching device is detected.A kind of current detection circuit commonly used is based on a kind of voltage-current converter circuit, is electric current by the voltage transitions with test point, by the reentry electric current of test point of this electric current.
As shown in Figure 1, inductance L 1 is connected with transistor MNsw, can obtain the current information of inductance L 1 by the electric current that detects transistor MNsw.When the MNsw conducting, MNsw is equivalent to a resistance, and the electric current on it equals the resistance of its voltage drop divided by it.As shown in fig. 1, the electric current of MNsw is the resistance R sw of the voltage Vsw of SW node divided by it.
Also show as resistance characteristic during the transistor MNse conducting of voltage-current converter circuit among Fig. 1, the electric current of transistor MNse place branch road is the resistance R se of the voltage Vse of MNse divided by MNse.When the breadth length ratio of MNsw was K times of breadth length ratio of MNse, MNsw was equivalent to the resistance parallel connection of K MNse, thus the conducting resistance of MNse be MNsw K doubly.The voltage Vsw of MNsw is as an input of electric current and voltage switching current in Fig. 1, and the voltage Vse of MNse is as another input of integrated transporting discharging, therefore the voltage Vsw of MNsw equates with the voltage Vse of MNse, because MNsw equates with the voltage of MNse, and the conducting resistance of MNse is K times of MNsw, and the electric current of the MNse that then flows through is the 1/K of the electric current of MNsw.
In the voltage-current converter circuit of Fig. 1, MP3 and MP5 form current mirror, therefore the electric current that the electric current of MP5 drain electrode output can image copying MNse, by measuring the output current of MP5 drain electrode, can try to achieve the electric current of MNse, and then can so just realize detecting the purpose of inductance L 1 electric current in the hope of the electric current of MNsw.
There are two shortcomings in the implementation method of Fig. 1: one, and its input voltage detection range is limited, and maximum input voltage needs less than VDD-VGSMP3, and VGSMP3 is the gate source voltage of MP3; Two, its output current precision can be subjected to the influence of the long mudulation effect of MP3 ditch, unequal as can cause the drain-source voltage VDS of MP3 and MP5 when supply voltage VDD changes, this moment, the current replication of the current mirroring circuit that MP3 and MP5 constitute changed than regular meeting, introduced error.
For overcoming the defective of circuit shown in Figure 1, a kind of improvement circuit as shown in Figure 2, by MP4, MN1, MN2, MP6, MP1, the feedback that MP2 forms is adjusted the drain voltage of MP3 and MP5 near equating.The method can solve the confined problem of input voltage detection range and suppress the influence of the long mudulation effect of MP3 ditch.But this method is because the time-delay of feedback network causes reaction speed slower, and when the variation of input voltage signal SW was very fast, the response speed of output current was slower, is not suitable for changing situation rapidly as the current detecting sort signal.
[utility model content]
The purpose of this utility model is to provide a kind of can reduce long mudulation effect influence of ditch and the fireballing voltage-current converter circuit of current response.
For reaching aforementioned purpose, a kind of voltage-current converter circuit of the utility model, it comprises:
Operational amplifier, it comprises first input end, second input, first output and second output;
First current branch, it comprises the first transistor, the 3rd transistor of mutual series connection;
Second current branch; It comprises transistor seconds, the 4th transistor of mutual series connection;
Wherein the grid of the first transistor and transistor seconds links to each other, the first transistor and transistor seconds constitute current mirror, the 3rd transistor links to each other with the 4th transistorized grid, the first input end of aforementioned operational amplifier receives input voltage, second input is connected in the current feedback node of first current branch, and the voltage of described current feedback node characterizes the electric current of first current branch; First output of operational amplifier is connected in the grid of the first transistor and transistor seconds, and second output of operational amplifier is connected in the 3rd transistor and the 4th transistorized grid; The 4th transistorized output of second current branch is as the switching current output.
Further, described the first transistor, transistor seconds, the 3rd transistor and the 4th transistor are the PMOS transistor.
Further, the source electrode and the substrate of the first transistor of described first current branch are connected in power supply, and the drain electrode of the first transistor is connected in the 3rd transistorized source electrode, and the grid of the first transistor links to each other with the grid of the transistor seconds of second current branch; The described the 3rd transistorized substrate is connected in power supply, and the 3rd transistorized grid links to each other with the 4th transistorized grid of second current branch, and the 3rd transistor drain is connected in aforementioned feedback node; Connect between aforementioned feedback node and a ground resistance or under conducting state, can equivalence be the transistor of resistance.
Further, the source electrode and the substrate of the transistor seconds of described second current branch are connected in power supply, and the drain electrode of transistor seconds is connected in the 4th transistorized source electrode; The 4th transistorized substrate is connected in power supply, and the 4th transistor drain is aforementioned switching current output.
Further, be in series with a resistance between first output of aforementioned operational amplifier and second output, the voltage difference of described first output and second output is the voltage at these resistance two ends.
Further, described operational amplifier is Origami cascaded operational amplifier structure, and described resistance string is coupled to the output branch road of operational amplifier.
Further, described operational amplifier is a current mirror operational amplifier structure, and described resistance string is coupled to the output branch road of operational amplifier.
Voltage-current converter circuit of the present utility model with respect to the prior art of Fig. 1 owing to increased by the 3rd transistor MP33 and the 4th transistor MP34 is equivalent to increase output impedance, thereby suppressed the long mudulation effect of ditch of the first transistor MP31.Prior art with respect to Fig. 2, the utility model adopts the dual output end of operational amplifier to control the first transistor MP31 respectively, the grid voltage of transistor seconds MP32 and the 3rd transistor MP33 and the 4th transistor MP34, the grid voltage that can realize the 3rd transistor MP33 and the 4th transistor MP34 always hangs down a fixed voltage than the grid voltage of the first transistor MP31 and transistor seconds MP32, the grid voltage that can guarantee the first transistor MP31 and transistor seconds MP32 like this has enough overdrive voltages, just can guarantee that by the utility model design this overdrive voltage is reliable and stable fixed voltage, can be along with the variation of input voltage and output current acute variation, when input voltage and output current change in wide range like this, the work that this circuit can be reliable and stable.And when input voltage changed, two outputs of the operational amplifier of dual output can almost respond simultaneously, had avoided the grid of MP1 in Fig. 2 prior art need pass through by MP4, MN2, MN1 just responds behind the additional feedback loop that MP6 forms, thereby has improved the response speed of entire circuit.
[description of drawings]
Fig. 1 is the structural representation of existing voltage-current converter circuit.
Fig. 2 is the structural representation of existing another voltage-current converter circuit.
Fig. 3 is the structural representation of voltage-current converter circuit of the present utility model
Fig. 4 is the first transistor MP31 of voltage-current converter circuit of the present utility model and the equivalent electric circuit of the 3rd transistor MP33.
Fig. 5 is the structural representation of the operational amplifier of voltage-current converter circuit of the present utility model.
Fig. 6 is the structural representation of another embodiment of operational amplifier of voltage-current converter circuit of the present utility model.
Fig. 7 is the operational amplifier structural representation of an embodiment again of voltage-current converter circuit of the present utility model.
[embodiment]
Alleged herein " embodiment " or " embodiment " are meant special characteristic, structure or the characteristic that can be contained at least one implementation of the utility model.Different in this manual local " in one embodiment " that occur not are all to refer to same embodiment, neither be independent or optionally mutually exclusive with other embodiment embodiment.
The transistor that is labeled as MP in the accompanying drawing is the PMOS transistor, the transistor that is labeled as MN is nmos pass transistor, below specification in do not specify NMOS pipe or PMOS pipe, label is that the transistor of MP is the PMOS transistor, label is that the transistor of MN is nmos pass transistor.In addition, the connection of being mentioned in this specification can be directly to link to each other, and also can be that middle ware is separated with linking to each other indirectly of other elements.
See also shown in Figure 3ly, it shows the structural representation of an embodiment of voltage-current converter circuit of the present utility model.
As shown in Figure 3, voltage-current converter circuit of the present utility model comprises the operational amplifier A of a dual input output.Wherein the first input end INM of operational amplifier A connects input voltage VIN, and the second input INP of operational amplifier A is connected in a feedback node N.This feedback node N is connected in the drain electrode of a nmos pass transistor MNse, and the source ground of transistor MNse, grid are connected in a control voltage Gate.Under the state of transistor MNse conducting, it can equivalence be a resistance also.Because the voltage of two inputs of operational amplifier A equates, therefore the voltage of the second input INP of operational amplifier A equals the voltage of first input end INM, just the voltage of feedback node N equals the input voltage VIN of first input end INM, therefore be under the situation of resistance in transistor MNse equivalence, MNse electric current be input voltage VIN/transistor MNse equivalent resistance.
Voltage-current converter circuit of the present utility model also comprises two first current branch and second current branch that constitute current mirror.Wherein first current branch comprises the first transistor MP31 and the 3rd transistor MP33.Second current branch comprises transistor seconds MP32 and the 4th transistor MP34.
Wherein the substrate of the first transistor MP31 of first current branch and source electrode are connected in power vd D, the grid of the first transistor MP31 links to each other with the grid of the transistor seconds MP32 of second current branch, and the drain electrode of the first transistor MP31 is connected in the source electrode of the 3rd transistor MP33.The substrate of the 3rd transistor MP33 is connected in power vd D, and the grid of the 3rd transistor MP33 links to each other with the grid of the 4th transistor MP34 of second current branch, and the drain electrode of the 3rd transistor MP33 is connected in aforementioned feedback node N.
Wherein the substrate of the transistor seconds MP32 of second current branch and source electrode are connected in power vd D, the grid of transistor seconds MP32 links to each other with the grid of the first transistor MP31 of first current branch, and the drain electrode of transistor seconds MP32 is connected in the source electrode of the 4th transistor MP34.The substrate of the 4th transistor MP34 is connected in power vd D, and the grid of the 4th transistor MP34 links to each other with the grid of the 3rd transistor MP33 of first current branch, and the drain electrode of the 4th transistor MP34 is as the switching current output of whole voltage-current converter circuit.
The first output OUT1 of aforementioned operational amplifier A is connected in the grid of the first transistor MP31 and transistor seconds MP32, the conducting of control the first transistor MP31 and transistor seconds MP32.The second output OUT2 of aforementioned operational amplifier A is connected in the grid of the 3rd transistor MP33 and the 4th transistor MP34, controls the conducting of the 3rd transistor MP33 and the 4th transistor MP34.
With respect to the prior art of Fig. 1, voltage-current converter circuit of the present utility model has increased the 3rd transistor MP33 and the 4th transistor MP34.If the 3rd transistor MP33 and the 4th transistor MP34 are operated in the saturation region, because its grid voltage is equal, and both threshold voltages equate that equivalence has increased output impedance, can solve the confined problem of input voltage detection range.And the influence of the long mudulation effect of the ditch that can suppress the first transistor MP1, help to improve the current precision of current replication.
Below with the width of the first transistor MP31 and transistor seconds MP32 and identical length etc., the width of the 3rd transistor MP33 and the 4th transistor MP34 and identical length etc. are that example (actual design not necessarily needs to equate, is for convenience of description) illustrates increase the 3rd transistor MP33 and the 4th transistor MP34 raising of current replication precision afterwards.
Suppose the drain voltage of the 3rd transistor MP33 and the 4th transistor MP34 there is some difference Δ V1, its difference that causes the two-way electric current to exist is Δ I1.When analyzing concerning between Δ V1 and the Δ I1, can carry out small-signal analysis to the cascade structure of the first transistor MP31 and the 3rd transistor MP33, its small-signal equivalent circuit figure as shown in Figure 4, power vd D does not change when considering the drain voltage change of the first transistor MP31 among Fig. 3, so can be ground with power vd D equivalence, then the small-signal equivalent circuit of the cascade structure of the first transistor MP31 and the 3rd transistor MP33 is that the parallel circuits of resistance R o1 and resistance R o3 and current source is in series, wherein Ro3 is the output resistance of the 3rd transistor MP33, Ro1 is the output resistance of the first transistor MP31, Δ Vs is the variation of the 3rd transistor MP33 source class voltage, Δ V1 is the variation of the 3rd transistor MP33 drain voltage, and Δ I1 is the variation of the 3rd transistor MP33 electric current.
According to the KCL theorem:
Find the solution and can get:
The negative sign is here represented changing in the opposite direction of voltage and current, and promptly drain voltage is low more, and electric current is big more; Drain voltage is high more, and electric current is more little.
Generally (gm1+gmb1) thus the value of Ro1Ro3 can be reduced to much larger than the value formula 2 of Ro1+Ro3:
And for the current mirror that does not have MP1 and MP2, the drain voltage difference of MP3 and MP5 and the pass of its current difference are:
Wherein Ro1 is the output resistance of the first transistor MP31.
Relatively formula 3 and formula 4 increase after the 3rd transistor MP33 and the 4th transistor MP34 as can be seen, and the difference between current Δ I that same drain voltage difference delta V causes has reduced (gm1+gmb1) Ro3 doubly.So increase by the 3rd transistor MP33 and the 4th transistor MP34 helps to improve the current replication current precision.
As shown in Figure 3, in the voltage-current converter circuit of the present utility model, the first output OU1 of operational amplifier A is used to control the grid voltage of the first transistor MP31 and transistor seconds MP32, and the second output OUT2 of operational amplifier A is used to control the grid voltage of the 3rd transistor MP33 and the 4th transistor MP34.When input voltage changed, two outputs of the operational amplifier of dual output can almost respond simultaneously, had avoided the grid of MP1 in Fig. 2 prior art need pass through by MP4, MN2, MN1 just responds behind the additional feedback loop that MP6 forms, thereby has improved the response speed of entire circuit.
The structure that is applied to several different dual output operational amplifier in Fig. 3 the utility model voltage-current converter circuit will be illustrated below respectively.
As shown in Figure 5, it shows the structural representation that is used for the dual output operational amplifier of voltage-current converter circuit shown in Figure 3 among embodiment of the utility model.As shown in Figure 5, it comprises input INM and input INP this operational amplifier, and wherein input INM is connected in the grid of a PMOS transistor MP51, and input INP is connected in the grid of the 2nd PMOS transistor MP52.
The source electrode of a described PMOS transistor MP51 and the 2nd PMOS transistor MP52 is connected in the end of one first current source I1 jointly, the other end of the described first current source I1 is connected in power supply V, and the substrate of a PMOS transistor MP51 and the 2nd PMOS transistor MP52 is connected in described power supply V jointly.
The drain electrode of the one PMOS transistor MP51 is connected in the drain electrode of one first nmos pass transistor MN51, the substrate of the described first nmos pass transistor MN51 and source ground, and wherein the drain electrode of the first nmos pass transistor MN51 links to each other with grid.
The drain electrode of the 2nd PMOS transistor MP52 is connected in the drain electrode of one second nmos pass transistor MN52, the substrate of the described second nmos pass transistor MN52 and source ground, and grid links to each other with the grid of the aforementioned first nmos pass transistor MN51.
The output branch road of described operational amplifier comprises one second current source I2, and the end of the second current source I2 is connected in power supply V, and the other end is as first output.First output links to each other with the drain electrode of one the 3rd nmos pass transistor MN53 by a resistance R 5, and the node that described resistance R 5 links to each other with the drain electrode of the 3rd nmos pass transistor MN53 is as second output.The grid of described the 3rd nmos pass transistor MN53 is connected in the drain electrode of the 2nd NOMS transistor MN2, source electrode and substrate ground connection.Between the drain electrode of the second nmos pass transistor MN52 and the first output OUT1, be connected in series with a resistance R 6 and a capacitor C 1.
Because the voltage of the first output OUT1 and the voltage difference of the second output OUT2 are the voltage at resistance R 5 two ends, the grid voltage that can realize the 3rd transistor MP33 and the 4th transistor MP34 like this always hangs down a fixed voltage than the grid voltage of the first transistor MP31 and transistor seconds MP32, the grid voltage that can guarantee the first transistor MP31 and transistor seconds MP32 like this has enough overdrive voltages, this fixed voltage can be determined by I2*R5, wherein I2 is the current value of current source I2, R5 is the resistance value of R5, this voltage generally is designed to 100～200mV and is advisable, too little meeting causes the source-drain voltage of the first transistor MP31 and transistor seconds MP32 too little and withdraw from the saturation region, if design the voltage dynamic range that too conference reduces the current conversion output.Just can guarantee that by the utility model design this overdrive voltage is reliable and stable fixed voltage, can be along with the variation of input voltage and output current acute variation, when input voltage and output current change in wide range like this, the work that this circuit can be reliable and stable.
See also shown in Figure 6ly, it shows the structure chart of another embodiment of the dual output operational amplifier that is used for voltage-current converter circuit shown in Figure 3 of the present utility model.As shown in Figure 6, this operational amplifier is Origami cascaded operational amplifier structure, and it comprises the first input end INP and the second input INM.First input end INP is connected in the grid of a PMOS transistor MP61, and the second input INM is connected in the grid of the 2nd PMOS transistor MP62.The substrate of the one PMOS transistor MP61 and the 2nd PMOS transistor MP62 is connected in power supply V jointly, the source electrode of the one PMOS transistor MP61 and the 2nd PMOS transistor MP62 is connected in the end of one first current source I1 jointly, and the other end of the described first current source I1 is connected in described power supply V.The drain electrode of the one PMOS transistor MP61 is connected in the end of one second current source I2, the other end ground connection of the described second current source I2.The drain electrode of the 2nd PMOS transistor MP62 is connected in the end of one the 3rd current source I3, the other end ground connection of described the 3rd current source I3.
Described operational amplifier also comprises a current mirror of being made up of the 3rd PMOS transistor MP63 and the 4th PMOS transistor MP64 and the first nmos pass transistor MN61 and the second nmos pass transistor MN62.Wherein source electrode and the substrate of the 3rd PMOS transistor MP63 and the 4th PMOS transistor MP64 all are connected in power supply V, and the grid of the 3rd PMOS transistor MP63 and the 4th PMOS transistor MP64 links to each other.
The drain electrode of the 3rd PMOS transistor MP63 links to each other with grid, and the drain electrode of the 3rd PMOS transistor MP63 simultaneously links to each other with the drain electrode of the first nmos pass transistor MN61.The substrate ground connection of the first nmos pass transistor MN61, source electrode are connected in the drain electrode of an aforementioned PMOS transistor MP61, and grid is connected in a control voltage Vb.
The drain electrode of the 4th PMOS transistor MP64 is as the first output OUT1 of integrated operational amplifier circuit, the first output OUT1 links to each other with the drain electrode of the second nmos pass transistor MN62 through a resistance R 5, and wherein the node that links to each other with the second nmos pass transistor MN62 of resistance R 5 is as the second output OUT2 of integrated operational amplifier circuit.The grid of the grid of the second nmos pass transistor MN62 and the aforementioned first nmos pass transistor MN61 is connected in aforementioned control voltage Vb jointly, the source electrode of the second nmos pass transistor MN62 is connected in the drain electrode of aforementioned the 2nd PMOS transistor MP62, the substrate ground connection of the second nmos pass transistor MN62.
Between the source electrode of the second nmos pass transistor MN62 and the first output OUT1, be in series with a resistance R 6 and a capacitor C 1.
Identical with aforementioned operational amplifier shown in Figure 5, operational amplifier shown in Figure 6, because the voltage of first output and the voltage difference of second output are the voltage at resistance R 5 two ends, when it is applied to voltage-current converter circuit shown in Figure 3, the grid voltage that can be implemented in the 3rd transistor MP33 and the 4th transistor MP34 in the voltage-current converter circuit shown in Figure 3 is always than low fixed voltage of grid voltage of the first transistor MP31 and transistor seconds MP32, the grid voltage that can guarantee the first transistor MP31 and transistor seconds MP32 like this has enough overdrive voltages, just can guarantee that by the utility model design this overdrive voltage is reliable and stable fixed voltage, can be along with the variation of input voltage and output current acute variation, when input voltage and output current change in wide range like this, the work that this circuit can be reliable and stable.And when input voltage changed, two outputs of the operational amplifier of dual output can almost respond simultaneously, had avoided the grid of MP1 in Fig. 2 prior art need pass through by MP4, MN2, MN1 just responds behind the additional feedback loop that MP6 forms, thereby has improved the response speed of entire circuit.
See also shown in Figure 7ly, it shows the structure chart that is used for the dual output operational amplifier of voltage-current converter circuit shown in Figure 3 of the present utility model.
As shown in Figure 7, this operational amplifier is a current mirror operational amplifier structure, and it comprises the first input end INM and the second input INP.Wherein first input end is connected in the grid of a PMOS transistor MP71, the second input INP is connected in the grid of the 2nd PMOS transistor MP72, the substrate of a described PMOS transistor MP71 and the 2nd PMOS transistor MP72 is connected in power supply V jointly, the public end that is connected in one first current source I1 of the source electrode of a described PMOS transistor MP71 and the 2nd PMOS transistor MP72, the other end of the described first current source I1 is connected in power supply V.
The drain electrode of a described PMOS transistor MP71 is connected in the drain electrode of one first nmos pass transistor MN71.The substrate of the described first nmos pass transistor MN71 and source ground, the grid of the first nmos pass transistor MN71 is connected with drain electrode.
The drain electrode of described the 2nd PMOS transistor MP72 is connected in the drain electrode of one second nmos pass transistor MN72.The substrate of the described second nmos pass transistor MN72 and source ground, grid links to each other with drain electrode.
Described operational amplifier also comprises a current mirror of being made up of the 3rd PMOS transistor MP73 and the 4th PMOS transistor MP74.Wherein source electrode and the substrate of the 3rd PMOS transistor MP73 and the 4th PMOS transistor MP74 all are connected in power supply V, and the grid of the 3rd PMOS transistor MP73 and the 4th PMOS transistor MP74 links to each other.
The grid of the 3rd PMOS transistor MP73 links to each other with drain electrode, and the drain electrode of the 3rd PMOS transistor MP73 simultaneously is connected in the drain electrode of one the 4th nmos pass transistor MN74.The grid of described the 4th nmos pass transistor MN74 is connected in the drain electrode of an aforementioned PMOS transistor MP71, the source electrode of the 4th nmos pass transistor MN74 and substrate ground connection.
The drain electrode of the 4th PMOS transistor MP74 is as the first output OUT1 of operational amplifier, and its drain electrode links to each other with the drain electrode of one the 3rd nmos pass transistor MN73 through a resistance R 5.The grid of described the 3rd NOMS transistor MN73 is connected in the drain electrode of aforementioned the 2nd PMOS transistor MP72, the source electrode of the 3rd NOMS transistor MN73 and substrate ground connection.Wherein the node that is connected with the drain electrode of the 3rd nmos pass transistor MN73 of resistance R 5 is as the second output OUT2 of operational amplifier.
Between the drain electrode of the 2nd PMOS transistor MP72 and the first output OUT1, be in series with a resistance R 6 and a capacitor C 1.
Identical with aforementioned operational amplifier shown in Figure 5, operational amplifier shown in Figure 7, because the voltage of first output and the voltage difference of second output are the voltage at resistance R 5 two ends, when it is applied to voltage-current converter circuit shown in Figure 3, the grid voltage that can be implemented in the 3rd transistor MP33 and the 4th transistor MP34 in the voltage-current converter circuit shown in Figure 3 is always than low fixed voltage of grid voltage of the first transistor MP31 and transistor seconds MP32, the grid voltage that can guarantee the first transistor MP31 and transistor seconds MP32 like this has enough overdrive voltages, just can guarantee that by the utility model design this overdrive voltage is reliable and stable fixed voltage, can be along with the variation of input voltage and output current acute variation, when input voltage and output current change in wide range like this, the work that this circuit can be reliable and stable.And when input voltage changed, two outputs of the operational amplifier of dual output can almost respond simultaneously, had avoided the grid of MP1 in Fig. 2 prior art need pass through by MP4, MN2, MN1 just responds behind the additional feedback loop that MP6 forms, thereby has improved the response speed of entire circuit.
Voltage-current converter circuit of the present utility model with respect to the prior art of Fig. 1 owing to increased by the 3rd transistor MP33 and the 4th transistor MP34 is equivalent to increase output impedance, thereby suppressed the long mudulation effect of ditch of the first transistor MP31.Prior art with respect to Fig. 2, the utility model adopts the dual output end of operational amplifier to control the first transistor MP31 respectively, the grid voltage of transistor seconds MP32 and the 3rd transistor MP33 and the 4th transistor MP34, the grid voltage that can realize the 3rd transistor MP33 and the 4th transistor MP34 always hangs down a fixed voltage than the grid voltage of the first transistor MP31 and transistor seconds MP32, the grid voltage that can guarantee the first transistor MP31 and transistor seconds MP32 like this has enough overdrive voltages, just can guarantee that by the utility model design this overdrive voltage is reliable and stable fixed voltage, can be along with the variation of input voltage and output current acute variation, when input voltage and output current change in wide range like this, the work that this circuit can be reliable and stable.And when input voltage changed, two outputs of the operational amplifier of dual output can almost respond simultaneously, had avoided the grid of MP1 in Fig. 2 prior art need pass through by MP4, MN2, MN1 just responds behind the additional feedback loop that MP6 forms, thereby has improved the response speed of entire circuit.
Above-mentioned explanation has fully disclosed embodiment of the present utility model.It is pointed out that and be familiar with the scope that any change that the person skilled in art does embodiment of the present utility model does not all break away from claims of the present utility model.Correspondingly, the scope of claim of the present utility model also is not limited only to previous embodiment.
Claims (7)
1. voltage-current converter circuit, it comprises:
Operational amplifier, it comprises first input end, second input, first output and second output;
First current branch, it comprises the first transistor, the 3rd transistor of mutual series connection;
Second current branch; It comprises transistor seconds, the 4th transistor of mutual series connection;
Wherein the grid of the first transistor and transistor seconds links to each other, the first transistor and transistor seconds constitute current mirror, the 3rd transistor links to each other with the 4th transistorized grid, the first input end of aforementioned operational amplifier receives input voltage, second input is connected in the current feedback node of first current branch, and the voltage of described current feedback node characterizes the electric current of first current branch; First output of operational amplifier is connected in the grid of the first transistor and transistor seconds, and second output of operational amplifier is connected in the 3rd transistor and the 4th transistorized grid; The 4th transistorized output of second current branch is as the switching current output.
2. voltage-current converter circuit as claimed in claim 1 is characterized in that: described the first transistor, transistor seconds, the 3rd transistor and the 4th transistor are the PMOS transistor.
3. voltage-current converter circuit as claimed in claim 2, it is characterized in that: the source electrode and the substrate of the first transistor of described first current branch are connected in power supply, the drain electrode of the first transistor is connected in the 3rd transistorized source electrode, and the grid of the first transistor links to each other with the grid of the transistor seconds of second current branch; The described the 3rd transistorized substrate is connected in power supply, and the 3rd transistorized grid links to each other with the 4th transistorized grid of second current branch, and the 3rd transistor drain is as aforementioned feedback node; Connect between aforementioned feedback node and a ground resistance or under conducting state, can equivalence be the transistor of resistance.
4. voltage-current converter circuit as claimed in claim 2 is characterized in that: the source electrode and the substrate of the transistor seconds of described second current branch are connected in power supply, and the drain electrode of transistor seconds is connected in the 4th transistorized source electrode; The 4th transistorized substrate is connected in power supply, and the 4th transistor drain is aforementioned switching current output.
5. voltage-current converter circuit as claimed in claim 1 is characterized in that: be in series with a resistance between first output of aforementioned operational amplifier and second output, the voltage difference of described first output and second output is the pressure drop at these resistance two ends.
6. voltage-current converter circuit as claimed in claim 5 is characterized in that: described operational amplifier is Origami cascaded operational amplifier structure, and described resistance string is coupled to the output branch road of operational amplifier.
7. voltage-current converter circuit as claimed in claim 5 is characterized in that: described operational amplifier is a current mirror operational amplifier structure, and described resistance string is coupled to the output branch road of operational amplifier.
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| CN2010205903168U CN201839193U (en) | 2010-11-03 | 2010-11-03 | Voltage and current conversion circuit |
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| CN2010205903168U CN201839193U (en) | 2010-11-03 | 2010-11-03 | Voltage and current conversion circuit |
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| CN102005921A (en) * | 2010-11-03 | 2011-04-06 | 无锡中星微电子有限公司 | Voltage-current switching circuit |
| CN103185632A (en) * | 2011-12-30 | 2013-07-03 | 北京林业大学 | Device for detecting weight of board |
| CN112445265A (en) * | 2019-09-04 | 2021-03-05 | 亚德诺半导体国际无限责任公司 | Voltage-current converter with complementary current mirror |
| CN115494903A (en) * | 2021-06-17 | 2022-12-20 | 联咏科技股份有限公司 | Voltage-current converter |
-
2010
- 2010-11-03 CN CN2010205903168U patent/CN201839193U/en not_active Expired - Lifetime
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102005921A (en) * | 2010-11-03 | 2011-04-06 | 无锡中星微电子有限公司 | Voltage-current switching circuit |
| CN102005921B (en) * | 2010-11-03 | 2013-02-13 | 无锡中星微电子有限公司 | Voltage-current switching circuit |
| CN103185632A (en) * | 2011-12-30 | 2013-07-03 | 北京林业大学 | Device for detecting weight of board |
| CN112445265A (en) * | 2019-09-04 | 2021-03-05 | 亚德诺半导体国际无限责任公司 | Voltage-current converter with complementary current mirror |
| CN112445265B (en) * | 2019-09-04 | 2022-04-29 | 亚德诺半导体国际无限责任公司 | Voltage-current converter and electronic component |
| CN115494903A (en) * | 2021-06-17 | 2022-12-20 | 联咏科技股份有限公司 | Voltage-current converter |
| CN115494903B (en) * | 2021-06-17 | 2024-04-19 | 联咏科技股份有限公司 | Voltage-current converter |
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