CN217063683U

CN217063683U - Transconductance amplifier

Info

Publication number: CN217063683U
Application number: CN202121551083.5U
Authority: CN
Inventors: 董良斌; 李冰玉
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-07-08
Filing date: 2021-07-08
Publication date: 2022-07-26
Anticipated expiration: 2031-07-08

Abstract

The utility model discloses a transconductance amplifier, which comprises a buffer isolation circuit for isolating an input signal and an output signal; the signal distribution circuit is used for matching the transconductance coefficient to evenly distribute the voltage signals output by the buffer isolation circuit; the transconductance conversion circuit is used for amplifying the voltage signals output by the signal distribution circuit into current signals in equal proportion; the buffer isolation circuit is connected with the signal distribution circuit, and the signal distribution circuit is connected with the transconductance conversion circuit, so that the beneficial effects are that a large current of hundreds of amperes can be output to a load, and when the frequency is from direct current to 40 kilohertz, the precision is within 0.3 percent, and when the frequency is from 40 kilohertz to 200 kilohertz, the precision is within 3 percent.

Description

Transconductance amplifier

Technical Field

The utility model belongs to the technical field of the amplifier, more specifically say, the utility model relates to a transconductance amplifier.

Background

In a common electronic circuit, a transconductance amplifier can only output dozens of milliamperes generally, and in practical application and theoretical research, particularly in the occasions of circuit simulation, power system simulation and transient analysis, test of various passive devices, calibration test of current sensors, electromagnetic analysis, radio frequency and plasma, low-frequency communication and the like, a verification tool which can output dozens or hundreds of amperes and has the frequency of more than 100K is needed, namely the transconductance amplifier.

The currently commonly used power system simulation amplifier has the following defects: firstly, the broadband output is met, and hundreds of amperes of current cannot be output; secondly, the output of a wide frequency band above 100K can not be satisfied in the condition of meeting the output of large current. At present, no transconductance amplifier capable of simultaneously outputting large current and wide frequency band exists in the market. The nominal bandwidth of the transconductance amplifier of Clarke-Hess8100 in the United states is 0-100K, the output current can reach 100A, but the maximum output voltage is 7V effective value, and the load with the impedance below 0.07 ohm can only be output when the output voltage is 100A, so that the practicability is not realized.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a transconductance amplifier to solve the technical problem that the transconductance amplifier that exists can not export broadband and heavy current simultaneously among the above-mentioned prior art.

In order to realize the technical purpose, the utility model adopts the following technical scheme:

a transconductance amplifier, comprising:

the buffer isolation circuit is used for isolating an input signal and an output signal, wherein the input signal and the output signal are both voltage signals;

the signal distribution circuit is used for matching transconductance coefficients to evenly distribute the voltage signals output by the buffer isolation circuit;

the transconductance conversion circuit is used for amplifying the voltage signals output by the signal distribution circuit into current signals in equal proportion;

the buffer isolation circuit is connected with the signal distribution circuit, and the signal distribution circuit is connected with the transconductance conversion circuit.

Preferably, the buffer isolation circuit includes a first operational amplifier, the first operational amplifier includes a non-inverting input terminal, an inverting input terminal and an output terminal, the non-inverting input terminal is used for inputting the voltage signal, and the output terminal is connected to the inverting input terminal.

Preferably, the signal distribution circuit comprises a plurality of sets of resistors.

Preferably, the number of the transconductance conversion circuits is multiple groups, and the transconductance conversion circuits are connected in parallel.

Preferably, the transconductance conversion circuit includes a second operational amplifier and a third operational amplifier, the second operational amplifier is connected to the signal distribution circuit, and the third operational amplifier is connected to the second operational amplifier.

Preferably, the transconductance conversion circuit further includes a high-frequency channel unit and a current boost circuit, and the high-frequency channel unit is connected to the current boost circuit.

Preferably, the high frequency channel unit includes a first diode, a second diode, and a resistor, and the resistor is connected to the first diode and the second diode, respectively.

Preferably, the current driving circuit includes a plurality of NPN transistors and a plurality of PNP transistors, and the number of the NPN transistors is plural.

Preferably, the current boost circuit employs discrete components.

Preferably, the transconductance transforming circuit further comprises a positive power supply, a negative power supply and a first capacitor.

The utility model provides a beneficial effect lies in:

1. the utility model discloses an isolation buffer circuit realizes keeping apart input signal and output signal for difficult production interference and intermodulation distortion between input signal and the output signal, and improved signal distribution circuit's area load capacity, when avoiding needing higher input power because of signal distribution circuit and transconductance conversion circuit, draw low input signal's voltage, the voltage that leads to output signal is not proportional.

2. The utility model discloses a signal distribution circuit realizes distributing the voltage signal of buffering the buffer isolation circuit output to transconductance conversion circuit in proportion for match the transconductance coefficient, make the proportion of input voltage signal value and output current value in the design range.

3. The utility model discloses a transconductance transform circuit realizes that the voltage signal equal proportion amplification of signal distribution circuit output is current signal, transconductance transform circuit's quantity is the multiunit, for parallelly connected structure between the transconductance transform circuit, the current signal of multiunit transconductance transform circuit parallelly connected back output doubles, the heavy current of hundred amperes can be exported gives the load, and the frequency is from direct current when 40 kilohertz, the precision is within 0.3%, the precision is within 3% when 40 kilohertz reaches 200 kilohertz.

4. The utility model discloses a high frequency channel unit and electric current push circuit realize promoting high frequency linearity through high frequency channel unit, reduce the power on the single transistor through electric current push circuit, adopt the parallelly connected form of multicrystal transistor, adopt the mode of complementary symmetry simultaneously, through the parallelly connected output that improves the electric current of multicrystal transistor.

5. The utility model discloses a current push circuit adopts discrete component, adopts discrete component more to do benefit to the heat dissipation on the one hand and dispel the heat evenly, and on the other hand can obtain wideer frequency band.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following descriptions are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

FIG. 1 is a schematic flow diagram of a transconductance amplifier;

FIG. 2 is a schematic diagram of a buffer isolation circuit;

FIG. 3 is a schematic diagram of a signal distribution unit;

fig. 4 is a schematic diagram of a transconductance conversion circuit.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

The present embodiment includes a transconductance amplifier, as shown in fig. 1, including a buffer isolation circuit for isolating an input signal and an output signal, where the input signal and the output signal are both voltage signals; the signal distribution circuit is used for matching the transconductance coefficient to evenly distribute the voltage signals output by the buffer isolation circuit; the transconductance conversion circuit is used for amplifying the voltage signals output by the signal distribution circuit into current signals in equal proportion; the buffer isolation circuit is connected with the signal distribution circuit, and the signal distribution circuit is connected with the transconductance conversion circuit.

As shown in fig. 2, the buffer isolation circuit includes a first operational amplifier AR1, the first operational amplifier AR1 includes a non-inverting input terminal, an inverting input terminal and an output terminal, the non-inverting input terminal is used for inputting a voltage signal, and the output terminal is connected to the inverting input terminal.

The isolation buffer circuit is a voltage follower constituted by the first operational amplifier AR1, and since the operational amplifier has an extremely high open loop gain, the voltage follower constituted by the operational amplifier does not require peripheral components, and at the same time, the performance is close to an ideal state, specifically, the voltage follower constituted by the first operational amplifier AR1 has an extremely high input impedance, draws little current from an input signal, that is, a voltage signal, and has an extremely low output impedance, and hardly causes a voltage drop inside when outputting a current.

Therefore, the method can be used for isolating the input signal and the output signal, so that interference and intermodulation distortion are not easily generated between the input signal and the output signal, the load carrying capacity of the signal distribution circuit is improved, and the condition that the voltage of the output signal is not proportional due to the fact that the voltage of the input signal is reduced when the signal distribution circuit and the transconductance conversion circuit need high input power is avoided.

The signal distribution circuit comprises a plurality of groups of resistors and is used for proportionally distributing the voltage signals output by the buffer isolation circuit to the transconductance conversion circuit. Specifically, as shown in fig. 3, in this embodiment, the signal distribution unit includes four sets of resistors, a parallel structure is formed between the four sets of resistors, each set of resistor includes two resistors connected in series, and the two resistors connected in series form a series voltage dividing circuit for matching a transconductance coefficient, so that a ratio of an input voltage signal value to an output current value is within a design range, where the transconductance coefficient refers to a ratio between a variation value of an output end current and a variation value of an input end voltage.

Specifically, taking two groups of resistors as an example, a twenty-first resistor R21 and a twenty-second resistor R22 are connected in series to form a first group of resistors, a twenty-third resistor R23 and a twenty-fourth resistor R24 are connected in series to form a second group of resistors, the first group of resistors and the second group of resistors are connected in parallel, and taking an input voltage of 5V as an example, after passing through a signal distribution circuit, an output voltage of each group is 0.5 times of the input voltage, that is, 2.5V. The signal distribution circuit completely uses the resistor to carry out voltage division, so that the output signal of the isolation buffer circuit passes through the signal distribution circuit and is output to the transconductance conversion circuit in proportion.

As shown in fig. 4, the transconductance transforming circuit includes a second operational amplifier AR2 and a third operational amplifier AR3, the second operational amplifier AR2 is connected to the signal distributing circuit, and the third operational amplifier AR3 is connected to the second operational amplifier AR 2. And the voltage follower formed by the second operational amplifier AR2 is used for isolating the input signal from the output signal and improving the current output precision under different load conditions. Since the second operational amplifier AR2 is substantially similar to the first operational amplifier AR1, the description is simple, and the relevant points can be found in the description of the first operational amplifier AR 1.

The transconductance conversion circuit further comprises a high-frequency channel unit and a current pushing circuit, wherein the high-frequency channel unit is connected with the current pushing circuit. Since the third operational amplifier AR3 cannot output a large current of hundreds of amperes, the current driving circuit is connected, and the third operational amplifier AR3 is connected with the current driving circuit.

The current pushing circuit comprises NPN transistors and PNP transistors, in order to reduce power on a single transistor, a multi-transistor parallel connection mode is adopted, meanwhile, a complementary symmetry mode is adopted, and current output is improved through the multi-transistor parallel connection mode, so that the number of the NPN transistors is multiple, and the number of the PNP transistors is multiple. The current driving circuit adopts discrete components, which are more favorable for heat dissipation and uniform heat dissipation on one hand, and can obtain wider frequency band on the other hand. The high-frequency channel unit comprises a first diode D1, a second diode D2 and a resistor, wherein the resistor is respectively connected with the first diode D1 and the second diode D2, and the high-frequency channel unit is used for improving high-frequency linearity.

In this embodiment, the transconductance conversion circuit further includes a positive power source VCC2, a negative power source VEE2, a first capacitor C1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor 17, an eighteenth resistor 18, a nineteenth resistor R19, and a twentieth resistor R20.

As a preferred embodiment, the number of NPN transistors is 5, and the number of PNP transistors is 5, specifically, the NPN transistors include a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, and a fifth transistor Q5, and the PNP transistors include a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8, a ninth transistor Q9, and a thirteenth transistor Q10.

The base of the fourth triode Q4 is connected with the fourth resistor R4, the collector of the fourth triode Q4 is connected with the third resistor R3, the emitter of the fourth triode Q4 is connected with the base of the fifth triode Q5, the collector of the fifth triode Q5 is connected with the first resistor R1, the emitter of the fifth triode Q5 is connected with the base of the first triode Q1, the base of the second triode Q2 and the base of the third triode Q3 respectively, the collector of the first triode Q1, the collector of the second triode Q2 and the collector of the third triode Q3 are all connected with the positive power source VCC2, and the emitter of the first triode Q1, the emitter of the second triode Q2 and the emitter of the third triode Q3 are all connected with the seventh resistor R7.

A base of the seventh transistor Q7 is connected to a seventeenth resistor R17, a collector of the seventh transistor Q7 is connected to an eighteenth resistor R18, an emitter of the seventh transistor Q7 is connected to a base of the sixth transistor Q6, a collector of the sixth transistor Q6 is connected to a nineteenth resistor R19, an emitter of the sixth transistor Q6 is connected to a base of the eighth transistor Q8, a base of the ninth transistor Q9 and a base of the thirteenth diode Q10, a collector of the eighth transistor Q8, a collector of the ninth transistor Q9 and a collector of the thirteenth diode Q10 are connected to a negative power source VEE2, an emitter of the eighth transistor Q8, an emitter of the ninth Q9 and an emitter of the thirteenth transistor Q10 are connected to a fourteenth resistor R14, an anode of the first diode D1 is connected to a positive power source VCC2, a cathode of the first diode D1 is connected to the twelfth resistor R12, the anode of the second diode D2 is connected to the fifteenth resistor R15, the cathode of the second diode D2 is connected to the negative power supply VEE2, and the first capacitor C1 is connected to the sixth resistor R6.

By changing the value of the eighth resistor R8, different coefficients of the voltage conversion current, i.e., transconductance coefficients, can be obtained. As shown in fig. 1, the number of the transconductance conversion circuits is multiple, the transconductance conversion circuits are connected in parallel, the transconductance conversion circuits are used for amplifying the voltage signals output by the signal distribution circuit into current signals in equal proportion, the current signals output by the multiple groups of transconductance conversion circuits after being connected in parallel are doubled, a large current of hundreds of amperes can be output to the load, and the precision is within 0.3% when the frequency is from dc to 40 khz, and the precision is within 3% when the frequency is from 40 khz to 200 khz.

It should be noted that:

reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment.

While the preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the invention.

In addition, it should be noted that the specific embodiments described in the present specification may be different in terms of the parts, the shapes of the components, the names of the components, and the like. All equivalent or simple changes made according to the structure, characteristics and principle of the utility model are included in the protection scope of the utility model. Those skilled in the art can modify or supplement the described embodiments or substitute them in a similar manner without departing from the scope of the invention as defined by the claims.

Claims

1. A transconductance amplifier, comprising:

the buffer isolation circuit is used for isolating an input signal and an output signal, wherein the input signal and the output signal are voltage signals;

2. A transconductance amplifier as claimed in claim 1, wherein said buffer isolating circuit comprises a first operational amplifier, said first operational amplifier comprising a non-inverting input for inputting said voltage signal, an inverting input and an output, said output being connected to said inverting input.

3. A transconductance amplifier as claimed in claim 1, characterized in that said signal distribution circuit comprises a plurality of sets of resistors.

4. A transconductance amplifier as claimed in claim 1, wherein said transconductance conversion circuits are in a plurality of groups, and said transconductance conversion circuits are connected in parallel.

5. A transconductance amplifier as claimed in claim 1, wherein said transconductance transforming circuit includes a second operational amplifier and a third operational amplifier, said second operational amplifier being connected to said signal splitting circuit, said third operational amplifier being connected to said second operational amplifier.

6. A transconductance amplifier as claimed in claim 1, characterized in that said transconductance transforming circuit further comprises a high frequency channel unit and a current boosting circuit, said high frequency channel unit and said current boosting circuit being connected.

7. A transconductance amplifier as claimed in claim 6, characterized in that said high-frequency channel unit comprises a first diode, a second diode and a resistor, said resistor being connected to said first diode and said second diode, respectively.

8. A transconductance amplifier as claimed in claim 6, wherein said current driving circuit includes a plurality of NPN transistors and a plurality of PNP transistors.

9. A transconductance amplifier as claimed in claim 6, characterized in that said current driving circuit employs discrete components.

10. A transconductance amplifier as claimed in claim 1, characterized in that said transconductance transforming circuit further comprises a positive supply, a negative supply and a first capacitor.