CN115208341A

CN115208341A - Transconductance amplifier circuit, power converter and electronic product

Info

Publication number: CN115208341A
Application number: CN202110381766.9A
Authority: CN
Inventors: 宋志军; 杜士才
Original assignee: Shanghai Awinic Technology Co Ltd
Current assignee: Shanghai Awinic Technology Co Ltd
Priority date: 2021-04-09
Filing date: 2021-04-09
Publication date: 2022-10-18

Abstract

The application provides a transconductance amplifier circuit, a power converter and an electronic product, because the output of the transconductance amplifier circuit is current, when no large compensation network is arranged at the rear stage of the output end of the transconductance amplifier circuit, the transconductance amplifier circuit has a faster response speed; in addition, because the voltage at two ends of the transconductance impedance is equal to the difference between the first voltage and the second voltage, the output current of the transconductance impedance completely flows into the negative feedback branch, and the mirror image output branch performs mirror image copy on the current in the negative feedback branch, the transconductance of the transconductance amplifier circuit is fixed, and therefore, when the transconductance amplifier circuit has a post-stage compensation network, the influence of the post-stage compensation network on the output current of the transconductance amplifier circuit can be reduced; in summary, the transconductance amplifier circuit can improve the response speed, i.e., the transient response performance, of the power converter.

Description

Transconductance amplifier circuit, power converter and electronic product

Technical Field

The present invention relates to the field of power electronics technologies, and in particular, to a transconductance amplifier circuit, a power converter, and an electronic product.

Background

At present, because the power converter product has higher conversion efficiency, the power converter product is widely applied to various electronic products as a power supply element.

The error amplifier is an indispensable critical part in most power converter control systems, and normally, a voltage operational amplifier is used as the error amplifier in the power converter control system, for example, a typical voltage operational amplifier adopting a three-type compensation manner as shown in fig. 1.

However, in general, the voltage operational amplifier needs to be provided with a relatively complicated compensation network, and due to the existence of the compensation network, the voltage adjustment speed of the output node COMP of the voltage operational amplifier is relatively slow, so when the voltage operational amplifier is applied to the power converter, the transient response performance of the power converter is affected.

Disclosure of Invention

In view of the above, the present invention provides a transconductance amplifier circuit, a power converter and an electronic product to improve transient response performance of the power converter.

In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:

a first aspect of the present invention provides a transconductance amplifier circuit, comprising: the current source comprises a transconductance impedance, a differential pair, a negative feedback branch, a mirror image output branch, an adjustable tail current source, a first bias current source and a second bias current source; wherein:

two receiving ends of the differential pair respectively receive a first voltage and a second voltage;

a first output end of the differential pair is grounded through the first bias current source, and a second output end of the differential pair is grounded through the second bias current source; the current values of the first bias current source and the second bias current source are equal;

the second input end of the differential pair is connected with the first input end of the differential pair through the transconductance impedance, and a connection point is connected with a power supply through the adjustable tail current source; the difference value between the output current of the adjustable tail current source and the first voltage and the second voltage meets a preset relation;

the acquisition end of the negative feedback branch circuit is connected with the second output end of the differential pair, and the feedback end of the negative feedback branch circuit is connected with the second input end of the differential pair;

when the difference value changes, the output current of the adjustable tail current source changes, and the negative feedback branch is used for adjusting the output current of the transconductance impedance, so that the output current of the first output end of the differential pair tends to the current value of the first bias current source, and the output current of the second output end of the differential pair tends to the current value of the second bias current source, so that the voltages at the two ends of the transconductance impedance are equal to the difference value, and the ratio of the output current of the transconductance impedance to the difference value is fixed;

in the output current of the transconductance impedance, the ratio of the current flowing into the feedback end of the negative feedback branch exceeds a preset ratio, so that the ratio of the current in the negative feedback branch to the difference is fixed when the difference is changed;

the mirror image output branch circuit is used for copying the current in the negative feedback branch circuit according to the mirror image proportion under the first preset proportion, and the mirror image output branch circuit is used as the output current of the transconductance amplifier circuit, so that when the difference value changes, the transconductance of the transconductance amplifier circuit is fixed.

Optionally, the negative feedback branch includes: a first switch tube; wherein:

the output end of the first switching tube is grounded, the input end of the first switching tube is used as the feedback end of the negative feedback branch, and the control end of the first switching tube is used as the acquisition end of the negative feedback branch;

the mirror image output branch comprises: a second switching tube; wherein:

the output end of the second switching tube is grounded; the input end of the second switch tube is used as the output end of the transconductance amplifier circuit; the control end of the second switch tube is connected with the second output end of the differential pair;

the differential pair, comprising: a third switching tube and a fourth switching tube; wherein:

the input end of the third switching tube is used as the first input end of the differential pair, the output end of the third switching tube is used as the first output end of the differential pair, and the control end of the third switching tube is used as the first control end of the differential pair;

the input end of the fourth switch tube is used as the second input end of the differential pair, the output end of the fourth switch tube is used as the second output end of the differential pair, and the control end of the fourth switch tube is used as the second control end of the differential pair.

Optionally, the types of the switching tubes in the negative feedback branch and the mirror image output branch are the same, the types of the switching tubes in the differential pair are the same, and the types of the switching tubes in the negative feedback branch and the mirror image output branch are opposite to the types of the switching tubes in the differential pair.

Optionally, the method further includes: a tail current regulation branch; wherein:

the sampling end of the tail current adjusting branch circuit is connected with the first output end of the differential pair, and the output end of the tail current adjusting branch circuit is connected with the control end of the adjustable tail current source;

the tail current adjusting branch circuit is used for increasing the output current of the adjustable tail current source when the output current of the first output end of the differential pair is smaller than the current value of the first current source, so that the output current of the adjustable tail current source and the difference value meet a preset relation.

Optionally, the tail current adjusting branch includes: an integral operation circuit and a current regulation branch circuit; wherein:

the current regulating branch circuit is arranged between the power supply and the ground; the control end of the current regulating branch circuit is connected with the output end of the integral operation circuit; the output end of the current regulating branch circuit is connected with the control end of the adjustable tail current source;

the integral operation circuit is used for controlling the current regulation branch circuit to reduce the output current of the adjustable tail current source when the voltage of the first output end of the differential pair is greater than a first reference voltage; when the voltage of the first output end of the differential pair is smaller than the first reference voltage, controlling the current adjusting branch circuit to increase the output current of the adjustable tail current source;

the first reference voltage is a voltage of the first output terminal of the differential pair when the output current of the first output terminal of the differential pair is equal to the current value of the first bias current source.

Optionally, the integrating operation circuit includes: an operational amplifier, a feedback resistor and a feedback capacitor; wherein:

the non-inverting input end of the operational amplifier receives the first reference voltage, the inverting input end of the operational amplifier receives the voltage of the first output end of the differential pair, and the output end of the operational amplifier serves as the output end of the integral operational circuit;

the feedback capacitor and the feedback resistor are connected in series between the output end of the operational amplifier and the inverting input end of the operational amplifier.

Optionally, the current regulating branch includes: a fifth switching tube and a sixth switching tube; wherein:

the output end of the fifth switching tube is grounded, and the input end of the sixth switching tube is connected with the power supply;

the control end of the fifth switching tube is used as the control end of the current regulating branch; the input end of the fifth switching tube is connected with the output end and the control end of the sixth switching tube, and the connection point is used as the output end of the current regulation branch.

Optionally, the adjustable tail current source includes: a seventh switching tube; wherein:

the input end of the seventh switching tube is used as the input end of the adjustable tail current source; the output end of the seventh switching tube is used as the output end of the adjustable tail current source; the control end of the seventh switching tube is used as the control end of the adjustable tail current source;

and the seventh switching tube is used for carrying out mirror image output of a second preset proportion on the current in the sixth switching tube.

Optionally, the method further includes: and the current limiting branch circuit is used for limiting the output current of the transconductance amplifier circuit to be a first threshold value by limiting the output current of the adjustable tail current source to be a second threshold value.

Optionally, the current limiting branch includes: the device comprises a first mirror image sampling branch, a limiting branch and a reference current source; wherein:

the first mirror image sampling branch and the reference current source are arranged between the power supply and the ground in series; the first image sampling branch circuit is used for sampling the output current of the adjustable tail current source according to a third preset proportion, copying the current in the current adjusting branch circuit according to a fourth preset proportion in an image mode, and taking the current as a first sampling current;

the limiting branch circuit is used for limiting the output current of the adjustable tail current source to be the second threshold value by limiting the output current of the first output end of the differential pair to be the current value of the first bias current source when the first sampling current is larger than or equal to the current value of the reference current source;

the current value of the reference current source is equal to the product of the third preset proportion and the second threshold value.

Optionally, the first mirror sampling branch includes: an eighth switching tube; wherein:

the input end of the eighth switching tube is connected with the power supply, the output end of the eighth switching tube is connected with the input end of the reference current source, and the control end of the eighth switching tube is connected with the output end of the tail current regulating branch;

the eighth switching tube is used for mirroring the current in the current regulation branch circuit according to a fourth preset proportion;

the limiting branch comprises: a ninth switching tube; wherein:

the output end of the ninth switch tube is connected with the first output end of the differential pair, the input end of the ninth switch tube is connected with the power supply, and the control end of the ninth switch tube is connected with the output end of the first mirror image sampling branch.

Optionally, the method further includes: and the clamping control branch circuit is used for clamping the output current of the transconductance amplifier circuit to be a third threshold value by clamping the output current of the second output end of the differential pair to be the current value of the second bias current source.

Optionally, the clamp control circuit includes: the second mirror image sampling branch circuit, the subtraction circuit and the clamping branch circuit; wherein:

the second image sampling branch circuit is used for imaging the output current of the transconductance amplifier circuit according to a fifth preset proportion and converting the output current into sampling voltage to be output;

the non-inverting input end of the subtraction circuit receives the sampling voltage, the inverting input end of the subtraction circuit receives a second reference voltage, and the subtraction circuit is used for outputting a clamping signal when the sampling voltage is greater than the second reference voltage; the second reference voltage is a voltage at the output end of the second sampling branch when the current in the second mirror image sampling branch is equal to a product of the fifth preset proportion and the third threshold;

and the clamping branch is used for clamping the output current of the second output end of the differential pair into the current value of the second bias current source when receiving the clamping signal.

Optionally, the second mirror sampling branch includes: a tenth switching tube and a divider resistor; wherein:

the input end of the tenth switching tube is connected with the power supply through the divider resistor, the output end of the tenth switching tube is grounded, the control end of the tenth switching tube is used as the sampling end of the second mirror image sampling branch, and the connection point of the tenth switching tube and the divider resistor is used as the output end of the second mirror image sampling branch;

the clamping branch comprises: an eleventh switching tube; wherein:

the output end of the eleventh switch tube is connected with the second output end of the differential pair, the input end of the eleventh switch tube is connected with the power supply, and the control end of the eleventh switch tube is connected with the output end of the subtraction circuit.

A second aspect of the present invention provides a power converter, wherein an error amplifier of a control system of the power converter is the transconductance amplifier circuit described in any one of the above paragraphs of the first aspect.

A third aspect of the present invention provides an electronic product including the power converter of the second aspect.

According to the technical scheme, the transconductance amplifier circuit provided by the invention has the advantages that as the output is the current, the transconductance amplifier circuit has higher response speed when no large compensation network is arranged at the rear stage of the output end of the transconductance amplifier circuit; in addition, in the transconductance amplifier circuit, when the difference between the first voltage and the second voltage changes, the negative feedback branch circuit adjusts the output current of the transconductance impedance to change the output current of the adjustable tail current source, so that the output current of the first output end of the differential pair tends to the current of the first bias current source, and the output current of the second output end of the differential pair tends to the current value of the second bias current source; the current values of the first bias current source and the second bias current source are equal, so that the voltage at two ends of the transconductance impedance is equal to the difference between the first voltage and the second voltage, namely the ratio of the output current of the transconductance impedance to the difference value is fixed; in the output current of the transconductance impedance, the ratio of the current flowing into the feedback end of the negative feedback branch exceeds a preset ratio, so that the ratio of the current in the negative feedback branch to the difference between the first voltage and the second voltage is fixed when the difference between the first voltage and the second voltage changes; the image output branch circuit carries out image proportion copy on the current in the negative feedback branch circuit and takes the current as the output current of the transconductance amplifier circuit, so that the transconductance of the transconductance amplifier circuit is fixed; therefore, when the transconductance amplifier circuit exists in the post-stage compensation network, the influence of the post-stage compensation network on the output current of the transconductance amplifier circuit can be reduced; in summary, the transconductance amplifier circuit can improve the response speed, i.e., the transient response performance, of the power converter.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, 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 description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a typical prior art voltage operational amplifier employing a triple-type compensation scheme;

fig. 2 to fig. 9 are schematic structural diagrams of 8 embodiments of transconductance amplifier circuits provided in the present application, respectively.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

In this application, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

In order to improve the transient response performance of the power converter, an embodiment of the present application provides a transconductance amplifier circuit, whose specific structure is shown in fig. 2, and includes: transconductance impedance 10, differential pair 21, negative feedback branch 22, mirror output branch 23, adjustable tail current source Iw, and first and second bias current sources IB1 and IB2.

In the transconductance amplifier circuit, two receiving terminals of a differential pair 21 respectively receive a first voltage VP and a second voltage VN; the first output terminal of the differential pair 21 is grounded via a first bias current source IB1, and the second output terminal is grounded via a second bias current source IB2.

The second input terminal of the differential pair 21 is connected to the first input terminal of the differential pair 21 through the transconductance impedance 10, the connection point is connected to the power source VIN through the adjustable tail current source Iw, and the difference between the output current of the adjustable tail current source Iw and the first voltage VP and the second voltage VN satisfies a preset relationship.

The acquisition end of the negative feedback branch 22 is connected with the second output end of the differential pair 21, and the feedback end of the negative feedback branch 22 is connected with the second input end of the differential pair 21; the acquisition end of the mirror image output branch 23 is connected with the acquisition end of the negative feedback circuit, and the output end of the mirror image output branch 23 is used as the output end of the transconductance amplifier circuit.

In addition, still be provided with: the current values of the first bias current source IB1 and the second bias current source IB2 are equal; in the output current of the transconductance impedance 10, the ratio that finally flows into the feedback end of the negative feedback branch 22 exceeds the preset ratio, that is, when the output current of the second output end of the differential pair 21 is equal to the current value of the second bias current source IB2, the ratio that flows into the feedback end of the feedback branch in the output current of the transconductance impedance 10 exceeds the preset ratio.

The preset ratio is a preset ratio that can ignore the current flowing into the second input terminal of the differential pair 21 in practical application, that is: the ratio is a predetermined ratio that can ignore the current value of the second bias current source IB2 in practical applications.

It should be noted that, in practical applications, the ratio of the current flowing into the feedback end of the negative feedback branch 22 in the output current of the transconductance impedance 10 finally exceeds the preset ratio by setting the current value of the second bias current source IB2 to be a minimum value, that is, by making the current value of the second bias current source IB2 much smaller than the current flowing into the negative feedback branch 22.

When the difference between the first voltage VP and the second voltage VN changes, the magnitude relationship between the output current of the first output terminal of the differential pair 21 and the current value of the first bias current source IB1 and the magnitude relationship between the output current of the second output terminal of the differential pair 21 and the current value of the second bias current source IB2 both change, so as to cause the negative feedback branch 22 to adjust the output current of the transimpedance 10 and the output current of the adjustable tail current source Iw, and further cause the output current of the first output terminal of the differential pair 21 to tend to the current value of the first bias current source IB1 and the output current of the second output terminal to tend to the current value of the second bias current source IB2.

Optionally, the difference between the first voltage VP and the second voltage VN changes, the first voltage VP changes, the second voltage VN changes, or both the first voltage VP and the second voltage VN change simultaneously, which is not specifically limited herein, and is all within the protection scope of the present application.

Since the current values of the first bias current source IB1 and the second bias current source IB2 are equal, it can be deduced from kirchhoff's voltage law that: the voltage across the transconductance impedance 10 is equal to the difference between the first voltage VP and the second voltage VN; as can be seen from the above, since the output current of the final transimpedance impedance 10 can be considered to be approximately all flowing into the negative feedback branch 22, the ratio of the current in the negative feedback branch 22 to the difference between the first voltage VP and the second voltage VN is fixed, i.e., the reciprocal of the transimpedance impedance value.

The mirror output branch 23 is configured to mirror-image proportionally copy a circuit in the negative feedback branch 22, and use a current after the proportional copy as an output current IGM of the transconductance amplifier circuit, so that a ratio of the output current IGM of the transconductance amplifier circuit to a difference between the first voltage VP and the second voltage VN is fixed, that is, transconductance of the transconductance amplifier circuit is fixed, and a proportion of the mirror-image copy of the mirror output branch 23 is set as a first preset proportion, so that transconductance of the transconductance amplifier circuit is a product of an inverse of a transconductance impedance value and the first preset proportion.

According to the technical scheme, the transconductance of the exaggeration amplifier circuit is fixed, so that when the transconductance amplifier circuit has a post-stage compensation network, the influence of the post-stage compensation network on the output current IGM of the transconductance amplifier circuit can be reduced; moreover, since the output of the self-current compensator is current, the self-current compensator has higher response speed when no large compensation network exists at the rear stage of the self-output end; therefore, the transconductance amplifier circuit can improve the response speed of the power converter, namely transient response performance.

It should be noted that, in the prior art, for example, in the voltage operational amplifier shown in fig. 1, due to the influence of the external compensation network, the output node of the voltage operational amplifier has a slow conversion speed for large signals, so that if the small signal bandwidth compensated by the system is to achieve a higher specification, the overall cost is higher; the transconductance amplifier circuit provided by the embodiment can improve the conversion speed of the output node to the large signal, so that the overall cost required by realizing a high specification of the small signal bandwidth compensated by the system can be reduced.

In another aspect of this embodiment, a specific implementation of the differential pair 21 is further provided, and a specific structure thereof is as shown in fig. 2, including: a third switching tube M3 and a fourth switching tube M4.

The input end of the third switching tube M3 is used as the first input end of the differential pair 21, the output end of the third switching tube M3 is used as the first output end of the differential pair 21, and the control end of the third switching tube M3 is used as the first receiving end of the differential pair 21; the input end of the fourth switching tube M4 is used as the second input end of the differential pair 21, the output end of the fourth switching tube M4 is used as the second output end of the differential pair 21, and the control end of the fourth switching tube M4 is used as the second receiving end of the differential pair 21.

The third switching tube M3 and the fourth switching tube M4 are of the same type, and preferably, as shown in fig. 2, both the third switching tube M3 and the fourth switching tube M4 are PMOS transistors.

It should be noted that, in practical applications, other embodiments are not excluded, for example, the third switching tube M3 and the fourth switching tube M4 are both NMOS transistors, which are not specifically limited herein and are within the protection scope of the present application as the case may be; however, it should be noted that the types of the third switching tube M3 and the fourth switching tube M4 need to be ensured to be opposite to the types of the first switching tube M1 and the second switching tube M2.

In another aspect, the present embodiment further provides an embodiment of the negative feedback branch 22, which has a specific structure as shown in fig. 2, and includes: the first switch tube M1.

The output end of the first switch tube M1 is grounded, the input end of the first switch tube M1 serves as the feedback end of the negative feedback branch 22, and the control end of the first switch tube M1 serves as the acquisition end of the negative feedback branch 22.

Preferably, as shown in fig. 2, the first switching transistor M1 is an NMOS transistor, and in practical applications, including but not limited to this embodiment, for example, the first switching transistor M1 may be a PMOS transistor, which is not specifically limited herein and is within the scope of the present application as the case may be.

The above is only one preferred embodiment of the negative feedback branch 22, and in practical applications, including but not limited to the above embodiments, it is not limited herein specifically, and it is within the scope of the present application as the case may be.

In another aspect of the present invention, a specific implementation of the mirror output branch 23 is further provided, and a specific structure of the mirror output branch is shown in fig. 2, where the specific implementation includes: and a second switch tube M2.

The output end of the second switch tube M2 is grounded; the input end of the second switch tube M2 is used as the output end of the mirror output branch 23 and also used as the output end of the transconductance amplifier circuit; the control end of the second switch tube M2 is used as the acquisition end of the mirror image output branch 23, and is connected to the second output end of the differential pair 21.

It should be noted that the second switch tube M2 needs to be used in cooperation with the first switch tube M1, and therefore needs to be selected according to the type of the first switch tube M1, for example, if the first switch tube M1 is an NMOS transistor, as shown in fig. 2, the second switch tube M2 should also be an NMOS transistor; and the mirror ratio of the second switch tube M2 to the first switch tube M1 is a first preset ratio.

The second switching tube M2 is an NMOS transistor, which is only a preferred embodiment of itself, and in practical applications, including but not limited to the above embodiments, for example, the second switching tube M2 may be a PMOS transistor, which is not specifically limited herein, and is within the protection scope of the present application as the case may be; however, it should be noted that the type of the second switch tube M2 needs to be guaranteed to be the same as the type of the first switch tube M1.

The above-mentioned is only a preferred embodiment of the mirror image output branch 23, and in practical applications, including but not limited to the above-mentioned embodiment, it is not limited herein specifically, and it is within the protection scope of the present application as the case may be.

Another embodiment of the present application provides a transconductance amplifier circuit, based on the transconductance amplifier circuit in the foregoing embodiment, the specific structure of which is shown in fig. 3, further including: a tail current regulating branch 30.

The sampling end of the tail current adjusting branch 30 is connected to the first output end of the differential pair 21, and the output end of the tail current adjusting branch 30 is connected to the control end of the adjustable tail current source Iw.

When the output current of the first output terminal of the differential pair 21 is smaller than the current value of the first current source, the tail current adjusting branch 30 increases the output current of the adjustable tail current source Iw; when the output current of the first output end of the differential pair 21 is smaller than the current value of the first current source, the tail current source adjusting branch circuit reduces the output current of the adjustable tail current source Iw; thereby, a preset relation between the output current of the adjustable tail current source Iw and the difference between the first voltage VP and the second voltage VN is realized.

Specifically, in the above-mentioned regulation mode, one embodiment of the tail current regulation branch 30, as shown in fig. 4, includes: an integral operation circuit 31 and a current regulation branch 32.

The inverting input end of the integral operation circuit 31 is used as the sampling end of the tail current regulation branch circuit 30 and is connected with the first output end of the differential pair 21; the non-inverting input terminal of the integral operation circuit 31 receives a first reference voltage VREF1; the output end of the integral operation circuit 31 is connected with the control end of the current regulation branch circuit 32; the output end of the current regulating branch 32 is connected with the control end of the adjustable tail current source Iw; the current regulating branch 32 is disposed between the power source VIN and ground; also, the first reference voltage VREF1 is also set as the voltage of the first output terminal of the differential pair 21 when the output current of the first output terminal of the differential pair 21 is equal to the current value of the first bias current source IB 1.

When the output current of the first output terminal of the differential pair 21 is greater than the current value of the first bias current source IB1, the voltage of the first output terminal of the differential pair 21 is greater than the first reference voltage VREF1, and when the output current of the first output terminal of the differential pair 21 is less than the current value of the first bias current source IB1, the voltage of the first output terminal of the differential pair 21 is less than the first reference voltage VREF1.

When the integrating operation circuit 31 determines that the voltage of the first output terminal of the differential pair 21 is greater than the first reference voltage VREF1, the control current adjusting branch circuit 32 decreases the output current of the adjustable tail current source Iw; when the integrating operation circuit 31 determines that the voltage of the first output terminal of the differential pair 21 is smaller than the first reference voltage VREF1, the control current adjusting branch 32 increases the output current of the adjustable tail current source Iw.

The above is only one preferred embodiment of the tail current adjusting branch circuit 30, and in practical applications, including but not limited to the above embodiment, it is not specifically limited herein, and it is within the scope of the present application as the case may be.

In another aspect of the present embodiment, an embodiment of the integrating operational circuit 31 is further provided, and a specific structure thereof is shown in fig. 4, and includes: the feedback circuit comprises an operational amplifier OP, a feedback resistor Rn and a feedback capacitor C.

The non-inverting input terminal of the operational amplifier OP is used as the non-inverting input terminal of the integrating operational circuit 31, and the inverting input terminal of the operational amplifier OP is used as the inverting input terminal of the integrating operational circuit 31; the output end of the operational amplifier OP serves as the output end of the integral operation circuit 31; the feedback capacitor C and the feedback resistor Rn are connected in series between the output terminal of the operational amplifier OP and the inverting input terminal of the operational amplifier OP to realize the stability compensation of the tail current adjusting branch 30.

The above is only one preferred embodiment of the integrating operation circuit 31, and in practical applications, including but not limited to the above embodiments, the embodiments are not limited herein, and may be within the protection scope of the present application.

In another aspect, the present embodiment further provides an embodiment of the current regulating branch 32, which has a specific structure as shown in fig. 4, and includes: a fifth switching tube M5 and a sixth switching tube M6.

The output end of the fifth switching tube M5 is grounded, and the input end of the sixth switching tube M6 is connected with the power supply VIN; the control end of the fifth switching tube M5 is used as the control end of the current regulating branch 32; the input end of the fifth switching tube M5 is connected to the output end and the control end of the sixth switching tube M6, and the connection point is used as the output end of the current adjusting branch 32.

Preferably, as shown in fig. 4, the fifth switching tube M5 is an NMOS transistor, and the sixth switching tube M6 is a PMOS transistor, and in practical applications, including but not limited to this embodiment, this embodiment is not specifically limited herein, and it is within the scope of the present application as the case may be.

The above is only one preferred embodiment of the current regulating branch 32, and in practical applications, including but not limited to the above embodiments, it is not limited herein specifically, and it is within the scope of the present application as the case may be.

In another aspect, this embodiment provides an implementation manner of the adjustable tail current source Iw to adapt to the adjustment of the tail current adjusting branch 30 to itself, and a specific structure of this implementation manner of the adjustable tail current source Iw is shown in fig. 5, which includes: and a seventh switching tube M7.

The input end of the seventh switching tube M7 is used as the input end of the adjustable tail current source Iw; the output end of the seventh switching tube M7 is used as the output end of the adjustable tail current source Iw; the control end of the seventh switching tube M7 is used as the control end of the adjustable tail current source Iw; the seventh switch M7 performs mirror image output of a second preset proportion on the current in the sixth switching tube M6.

Preferably, as shown in fig. 5, the seventh switching transistor M7 is a PMOS transistor, and in practical applications, including but not limited to this embodiment, it is not limited herein specifically, and it is within the scope of the present application as the case may be; it should be noted that the seventh switch M7 needs to use the same type of transistor as the sixth switch M6.

The above is only one preferred embodiment of the adjustable tail current source Iw, and in practical applications, including but not limited to the above embodiments, it is not limited herein specifically, and it is within the scope of the present application as the case may be.

Taking the transconductance amplifier circuit shown in fig. 5 as an example, the following describes an adjustment process of the transconductance amplifier circuit after the input signal changes, where the adjustment process specifically is:

when the first voltage VP is unchanged and the second voltage VN jumps downward, the gate-source voltage of the fourth switching tube M4 increases, the current in the fourth switching tube M4 increases and is greater than the power supply value of the second bias current source IB2, that is, the output current of the second output terminal of the differential pair 21 increases and is greater than the power supply value of the second bias current source IB 2; meanwhile, since the current on the seventh switching tube M7 is not yet available and adjusted, the seventh switching tube M7 cannot meet the current requirement of each branch of its own subordinate, so that the current on the third switching tube M3 is smaller than the power supply value of the first bias current source IB1, that is, the voltage of the first output end of the differential pair 21 is decreased and lower than the first reference voltage VREF1, thereby increasing the gate-source voltage and the current of the fifth switching tube M5, further increasing the current of the sixth switching tube M6, and thus increasing the current on the seventh switching tube M7, until the current on the seventh switching tube M7 can meet the circuit requirement of each branch of its own lower side, the tail current adjusting branch 30 completes the increase adjustment; finally, the transconductance amplifier circuit tends to be stable again, that is, the current on the third switching tube M3 tends to the current value of the first bias current source IB1, and the current on the fourth switching tube M4 tends to the current value of the second bias current source IB 2; after the transconductance amplifier circuit is stabilized again, since the current of the fourth switching tube M4 is increased compared to the previous one, the current of the first switching tube M1 is also increased compared to the previous one, and thus the current of the second switching tube M2 is increased compared to the previous one, i.e. the output current IGM of the transconductance amplifier circuit is increased compared to the previous one.

When the first voltage VP is unchanged and the second voltage VN jumps upwards, the gate-source voltage of the fourth switching tube M4 decreases, the current decreases and is smaller than the power supply value of the second bias current source IB2, that is, the output current of the second output terminal of the differential pair 21 decreases and is smaller than the power supply value of the second bias current source IB 2; meanwhile, since the current of the seventh switching tube M7 is not yet available and adjusted, the current of the seventh switching tube M7 is greater than the current requirement of each branch of the next stage of the seventh switching tube M7, so that the current of the third switching tube M3 is greater than the power supply value of the first bias current source IB1, that is, the voltage of the first output end of the differential pair 21 is increased and is higher than the first reference voltage VREF1, thereby decreasing the gate-source voltage and the current of the fifth switching tube M5, further increasing the current of the sixth switching tube M6, and thus decreasing the current of the seventh switching tube M7, and the tail current adjusting branch 30 completes the turn-down adjustment until the current of the seventh switching tube M7 just meets the circuit requirement of each branch below the seventh switching tube M7; finally, the transconductance amplifier circuit tends to be stable again, that is, the current on the third switching tube M3 tends to the current value of the first bias current source IB1, and the current on the fourth switching tube M4 tends to the current value of the second bias current source IB2. After the transconductance amplifier circuit is stabilized again, since the current of the fourth switching tube M4 is reduced compared to before, the current of the first switching tube M1 is also reduced compared to before, so that the current of the second switching tube M2 is reduced compared to before, that is, the output current IGM of the transconductance amplifier circuit is reduced compared to before.

Therefore, after the transconductance amplifier circuit tends to be stable, the current of the third switching tube M3 is equal to the current value of the first bias current source IB1, and the current of the fourth switching tube M4 is equal to the current value of the second bias current source IB2, so that the voltage Vo = VP + VSG _ M3-VN-VSG _ M4 across the transconductance impedance 10; wherein VP is a first voltage, VN is a second voltage, VSG _ M3 is a gate-source voltage of the third switching tube M3, and VSG _ M4 is a gate-source voltage of the fourth switching tube M4.

Since the current value of the first bias current source IB1 is equal to the current value of the second bias current source IB2, that is, the current on the third switching tube M3 is equal to the current on the fourth switching tube M4, the gate-source voltage VSG _ M3 of the third switching tube M3 is equal to the gate-source voltage VSG _ M4 of the fourth switching tube M4, that is, the voltage Vo = VP-VN across the transconductance impedance 10, and since the voltage across the transconductance impedance 10 can also be expressed as: vo = Io Ro, so VP-VN = Io Ro, where Io is the current across the transconductance impedance 10 and Ro is the resistance of the transconductance impedance 10.

Since the current values of the first bias current source IB1 and the second bias current source IB2 are equal, and the output current of the transconductance impedance 10 can be regarded as approximately all flowing into the first switch tube M1, the output of the differential pair 21 is applied to the transconductance GMo = Io/(VP-VN) of the first switch tube M1, and further, VP-VN = Io Ro is substituted to obtain: GMo =1/Ro; thus, the transconductance GM = IGM/(VP-VN) = k Io/(VP-VN) = k/Ro of the transconductance amplifier circuit; wherein, IGM is an output current of the transconductance amplifier circuit, and k is a first predetermined proportion.

In summary, the transconductance GM of the transconductance amplifier is related to the transconductance impedance 10 and the mirror ratio of the second switching tube M2 and the first switching tube M1, and is not related to the differential pair 21 and the operating point voltage; the transconductance of the transconductance amplifier circuit is therefore fixed after setting the transconductance impedance 10.

In the foregoing embodiment, the transconductance amplifier circuit may adjust the current value of the adjustable tail current source Iw through the tail current adjusting branch circuit 30, but if the current value of the adjustable tail current source Iw is adjusted to be large, the transconductance amplifier circuit may damage itself or other devices in the transconductance amplifier circuit, and in order to avoid damaging the adjustable tail current source Iw or other devices in the transconductance amplifier circuit, another embodiment of the present application provides another implementation manner of the transconductance amplifier circuit, and on the basis of the transconductance amplifier circuit provided in the foregoing embodiment, the implementation manner further includes: and the current limiting branch circuit 40 limits the output current IGM of the transconductance amplifier circuit to a first threshold value by limiting the output current of the adjustable tail current source Iw to a second threshold value by the current limiting branch circuit 40.

Specifically, one connection relationship between the current limiting branch 40 and the other branches is shown in fig. 6, specifically:

the sampling terminal of the current limiting branch 40 is connected to the control terminal of the adjustable tail current source Iw, and the output terminal of the current limiting branch 40 is connected to the first output terminal of the differential pair 21.

When the current value of the adjustable tail current source Iw is greater than or equal to the second threshold, the current limiting branch 40 limits the output current of the first output terminal of the differential pair 21, so that the output current of the first output terminal of the differential pair 21 is equal to the current value of the first bias current source IB1, and thus the tail current adjusting branch 30 does not adjust the current value of the adjustable tail current source Iw any more, that is, the current value of the adjustable tail current source Iw is limited to the second threshold; when the current value of the adjustable tail current source Iw is smaller than the second threshold, the current limiting branch 40 does not limit the output current of the first output terminal of the differential pair 21, i.e. does not affect the normal operation of the tail current adjusting branch 30.

The ratio of the output current of the tail current source Iw to the output current IGM of the transconductance amplifier circuit is equal to the ratio of the first threshold value to the second threshold value.

The above is only one preferred connection relationship of the current limiting branch 40, and in practical applications, including but not limited to the above embodiments, it is not limited herein specifically, and it is within the scope of the present application as the case may be.

In another aspect, the present embodiment provides a specific implementation of the current limiting branch 40, which has a specific structure as shown in fig. 7, and includes: a first mirror sampling branch 41, a limiting branch 42 and a reference current source IR.

The first image sampling branch 41 and the reference current source IR are serially connected between the power source VIN and the ground, and a sampling end of the first image sampling branch 41 serves as a sampling end of the current limiting branch 40; and, the first mirror sampling branch 41 samples the output current of the adjustable tail current source Iw at a third preset ratio and mirror copies the current in the current adjusting branch 30 at a fourth preset ratio as a first sampling current.

The sampling terminal of the limiting branch 42 is connected to the connection point of the first mirror sampling branch 41 and the reference current source IR, and the output terminal of the limiting branch 42 serves as the output terminal of the current limiting branch 40.

When the first sampling current is greater than or equal to the current value of the reference current source IR, the limiting branch 42 limits the output current of the adjustable tail current source Iw to the second threshold value by limiting the output current of the first output terminal of the differential pair 21 to the current value of the first bias current source IB 1; when the first sampled current is smaller than the current value of the reference current source IR, the limiting branch 42 does not affect the normal operation of the tail current adjusting branch 30.

Wherein the current value of the reference current source IR is equal to the product of the third preset proportion and the second threshold.

It should be noted that, since the current value of the reference current source IR is equal to the product of the third preset ratio and the second threshold, the first sampling current is greater than or equal to the current value of the reference current source IR, that is: the current value of the adjustable tail current source Iw is equal to or greater than the second threshold, and therefore, this embodiment can implement the above-described functions.

The above is only one preferred embodiment of the current limiting branch 40, and in practical applications, including but not limited to the above embodiments, it is not limited herein specifically, and it is within the scope of the present application as the case may be.

In another aspect of this embodiment, a specific implementation of the first mirror sampling branch 41 is further provided, and a specific structure of the first mirror sampling branch is shown in fig. 7, where the specific implementation includes: an eighth switching tube M8.

The input end of the eighth switching tube M8 is connected to the power supply VIN, the output end of the eighth switching tube M8 is connected to the input end of the reference current source IR, and the control end of the eighth switching tube M8 serves as the sampling end of the first mirror sampling branch 41; the eighth switching tube M8 performs a mirror copy of the current in the current regulating branch 30 at a fourth preset ratio.

Preferably, as shown in fig. 7, the eighth switching transistor M8 is a PMOS transistor, and in practical applications, other embodiments are not excluded, and are not specifically limited herein, and all of which are within the protection scope of the present application as the case may be.

It should be noted that the eighth switching tube M8 needs to select the same type of transistor as the sixth switching tube M6 and the seventh switching tube M7, and the mirror ratio of the eighth switching tube M8 to the seventh switching tube M7 is equal to the third preset ratio.

In another aspect of this embodiment, a specific implementation of the limiting branch 42 is further provided, and a specific structure thereof is as shown in fig. 7, including: and a ninth switching tube M9.

The output end of the ninth switching tube M9 serves as the output end of the limiting branch 42; the input end of the ninth switching tube M9 is connected to the power supply VIN; the control terminal of the ninth switching tube M9 serves as the sampling terminal of the limiting branch 42.

It should be noted that, in this embodiment of the limiting branch 42, in order to ensure that the ninth switching tube M9 can be turned on when the first sampling current is equal to or greater than the current value of the reference current source IR, it is therefore set that: the conduction threshold of the ninth switching tube M9 is a voltage at a connection point of the first mirror image sampling branch 41 and the first reference power supply IR when the first sampling current is equal to the current value of the reference current source IR.

Preferably, as shown in fig. 7, the ninth switching transistor M9 is an NMOS transistor, and in practical applications, other embodiments are not excluded, and are not specifically limited herein, and may be within the protection scope of the present application as the case may be.

It should be noted that, the limitation on the maximum output current of the transconductance amplifier circuit is realized by sampling the current value of the adjustable tail current source Iw and comparing the current value with the reference current, and the limitation on the output current IGM of the transconductance amplifier circuit is more accurate.

The following describes the operation process of the current limiting branch circuit 40 by taking the transconductance amplifier circuit shown in fig. 7 as an example, specifically:

the eighth switching tube M8 mirrors the current in the seventh switching tube M7 at a third preset ratio, and when the current in the seventh switching tube M7 is smaller than the second threshold, the current in the eighth switching tube M8 is smaller than the current value of the reference current source IR, that is, the voltage at the connection point of the eighth switching tube M8 and the reference current source IR is smaller than the conduction threshold of the ninth switching tube M9, and the ninth switching tube M9 is turned off, so that the normal operation of the tail current adjusting branch 30 is not affected.

When the current of the seventh switching tube M7 is greater than or equal to the second threshold, the current of the eighth switching tube M8 is greater than or equal to the current value of the reference current source IR, that is, the voltage at the connection point of the eighth switching tube M8 and the reference current source IR is greater than the conduction threshold of the ninth switching tube M9, the ninth switching tube M9 is turned on, and a current is injected into the connection point of the first output end of the differential pair 21 and the first bias current source IB1, so that the voltage of the first output end of the differential pair 21 does not continuously decrease and is kept stable, even if the output current of the first output end of the differential pair 21 does not continuously decrease and is kept stable, the current of the fifth switching tube M5 does not increase and is kept stable, and the current of the seventh switching tube M7 does not increase and is kept at the second threshold.

At this time, the current on the seventh switching tube M7 does not increase any more, so when the current on the fourth switching tube M4 is equal to the current value of the second bias current source IB2, that is, the transconductance amplifier circuit tends to be stable, the output current IGM of the transconductance amplifier circuit is limited to the first threshold.

Wherein the first threshold is:

since the current values of the first bias current source IB1 and the second bias current source IB2 are the same, on the basis that it is approximately considered that the output current of the transconductance impedance 10 all flows into the first switching tube M1, it can also be approximately considered that the output current of the adjustable tail current source Iw all only flows into the first switching tube M1, that is, the current in the first switching tube M1 is equal to the output current of the adjustable tail current source Iw, so that the first threshold I1= k I2= k Iref1/k1; wherein I2 is the second threshold, k is the first preset ratio, k1 is the third preset ratio, and Iref1 is the current value of the reference current source IR.

It can be seen that when the difference between the first voltage VP and the second voltage VN of the transconductance amplifier circuit is too large, the output current IGM of the transconductance amplifier circuit will be limited to the first threshold, i.e. the maximum output current value of the transconductance amplifier circuit; in addition, after the current limiting branch circuit 40 is arranged in the transconductance amplifier circuit, because the transconductance amplifier circuit normally works until the current limiting circuit enters the current limiting state, and the voltages at the two ends of the transconductance are both in a small value, in the power converter with low precision requirement, the input offset generated by the source end of one switching tube in the differential pair 21, which is provided with the transconductance impedance 10, can be ignored; when the design offset is large, the system can reduce the establishment time of transient jump due to the offset, thereby obtaining better transient response.

In the foregoing embodiment, the transconductance amplifier circuit may adjust the current value of the adjustable tail current source Iw through the tail current adjusting branch 30, however, if the current value of the adjustable tail current source Iw is adjusted to be very small, the output current IGM of the transconductance amplifier circuit may cause an influence, that is, the output current IGM output by the transconductance amplifier circuit has a large error at this time, in order to avoid this phenomenon, another embodiment of the transconductance amplifier circuit is provided in this application, a specific structure of which is shown in fig. 8, and on the basis of the transconductance amplifier circuit provided in the foregoing embodiment, the method further includes: the clamp control branch 50.

The sampling end of the clamping control branch 50 is connected with the second output end of the differential pair 21, and the output end of the clamping control branch 50 is connected with the second output end of the differential pair 21.

When the output current of the second output terminal of the differential pair 21 is smaller than the fourth threshold value, the output current IGM of the transconductance amplifier circuit is clamped to the third threshold value by clamping the output current of the second output terminal of the differential pair 21 by the clamping control branch 50 to the current value of the second bias current source IB2.

Wherein, the ratio of the third threshold value to the fourth threshold value is equal to a first preset proportion.

Another embodiment of the present invention provides a specific implementation of a clamp control circuit, which has a specific structure as shown in fig. 9, and includes: a second mirror sampling branch 51, a subtraction circuit 52 and a clamping branch 53.

The sampling end of the second mirror image sampling circuit is used as the sampling end of the clamp control circuit, the output end of the second mirror image sampling circuit is connected with the non-inverting input end of the subtraction operation circuit 52, and the second mirror image sampling circuit mirrors the output current IGM of the transconductance amplifier circuit according to a fifth preset proportion and converts the output current IGM into sampling voltage for output.

An inverting input terminal of the subtraction circuit 52 receives the second reference voltage Vref2; the second reference voltage Vref2 is a voltage at the output terminal of the second sampling branch when the current in the second mirror sampling branch is equal to a product of the fifth preset proportion and the third threshold.

The control end of the clamping branch 53 is connected with the output end of the subtraction circuit 52, and the output end of the clamping branch 53 is used as the output end of the clamping control circuit.

When the sampled voltage is greater than the second reference voltage Vref2, the clamping branch 53 clamps the output current of the second output terminal of the differential pair 21 to the current value of the second bias current source IB2.

Optionally, the subtracting circuit 52 may be an operational amplifier, and in practical applications, other embodiments are not excluded, and are not specifically limited herein, and all of them are within the protection scope of the present application as the case may be.

The above is only one preferred embodiment of the clamp control circuit, and in practical applications, including but not limited to the above embodiments, the embodiments are not specifically limited herein, and may be within the protection scope of the present application as the case may be.

It should be noted that the minimum output current of the transconductance amplifier circuit is clamped by sampling the output current IGM of the transconductance amplifier circuit and amplifying by an operational amplifier, so that the clamping of the output current IGM of the transconductance amplifier circuit is more accurate.

It should be noted that, in the prior art, if the current limiting and clamping functions are required in the power converter using the voltage operational amplifier, additional circuit modules are required to be added for implementation, which results in the cost and design complexity of the power converter. In the embodiment, the current limiting and clamping functions are built in through a multi-loop design. Meanwhile, the integration of a plurality of functions is realized, so that the module design of the system is simplified, and the transconductance amplifier circuit is very suitable for being used as a system error amplifier in a power converter control system.

In another aspect, this embodiment provides a specific implementation manner of the second mirror sampling branch 51, and a specific structure thereof is as shown in fig. 9, and includes: a tenth switching tube M10 and a voltage dividing resistor Ra.

The input end of the tenth switching tube M10 is connected to the power supply VIN through the voltage-dividing resistor Ra, the output end of the tenth switching tube M10 is grounded, the control end of the tenth switching tube M10 serves as the sampling end of the second mirror image sampling branch 51, and the connection point of the tenth switching tube M10 and the voltage-dividing resistor Ra serves as the output end of the second mirror image sampling branch 51.

The above is only one preferred embodiment of the second mirror sampling branch 51, and in practical applications, including but not limited to the above embodiments, it is not limited herein specifically, and it is within the scope of the present application as the case may be.

In another aspect, this embodiment provides a specific implementation of the clamping branch 53, and the specific structure thereof is as shown in fig. 9, and includes: an eleventh switch tube M11.

An output end of the eleventh switch M11 serves as an output end of the clamping branch 53, an input end of the eleventh switch M11 is connected to the power source VIN, and a control end of the eleventh switch M11 serves as a control end of the clamping branch 53.

The above is only one preferred embodiment of the clamping branch 53, and in practical applications, including but not limited to the above embodiments, it is not limited herein specifically, and it is within the scope of the present application as the case may be.

The following describes the operation process of the clamp control branch 50 by taking the transconductance amplifier circuit shown in fig. 9 as an example, specifically:

the tenth switching tube M10 mirrors the current on the second switching tube M2 according to a fifth preset proportion, and when the voltage at the output end of the tenth switching tube M10 is smaller than the second reference voltage Vref2, the subtraction operation circuit 52 controls the eleventh switching tube M11 to be always turned off, so that the normal operation of the transconductance amplifier circuit is not affected.

When the voltage at the output end of the tenth switching tube M10 is greater than or equal to the second reference voltage Vref2, the subtraction circuit 52 controls the eleventh switching tube M11 to be turned on, and injects a current to the connection point between the second output end of the differential pair 21 and the second bias current source IB2, so that the gate voltage of the first switching tube M1 does not decrease any more, and thus the current on the tenth switching tube M10 does not decrease any more, and further the minimum output current of the transconductance amplifier circuit is clamped, and finally the voltage at the output end of the tenth switching tube M10 is clamped near the second reference voltage Vref 2.

Since the voltage at the output end of the tenth switching tube M10 is finally clamped near the second reference voltage Vref2, the third threshold value I3= (VIN-Vref 2)/Ra/k 2, and the fourth threshold value I4= I3/k = (VIN-Vref 2)/Ra/k 2/k; wherein Vref2 is a second reference voltage, k2 is a fifth preset proportion, k is a first preset proportion, ra is a voltage dividing resistor, and VIN is a power voltage.

It can be seen that when the difference between the first voltage VP and the second voltage VN of the transconductance amplifier circuit is too small, the output current IGM of the transconductance amplifier circuit will be clamped to the third threshold, i.e. the minimum output current value of the transconductance amplifier circuit.

Another embodiment of the present application provides a power converter, where an error amplifier of a control system of the power converter is the transconductance amplifier circuit provided in the foregoing embodiment.

It should be noted that, the open-circuit amplifier circuit is sampled as an error amplifier, which is beneficial to design a power converter with better transient response performance, and if current limiting and clamping performance are required inside the power converter, since the transconductance amplifier circuit is built with the current limiting branch 40 to implement current limiting and the clamp control branch 50 to implement current clamping, no additional circuit module is required to be added to implement the current limiting and clamping, so that the design complexity and cost are reduced.

Another embodiment of the present application provides an electronic product, including the power converter provided in the above embodiment.

The structure and principle of the power converter can be seen in the above embodiments, and are not described in detail.

In addition, the electronic product may be any electronic product provided with the power converter, and is not limited herein and is within the protection scope of the present application.

In the above description of the disclosed embodiments, features described in various embodiments in this specification can be substituted for or combined with each other to enable those skilled in the art to make or use the present application. The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. Although the present invention has been described with reference to the preferred embodiments, it is not intended to be limited thereto. Those skilled in the art can make numerous possible variations and modifications to the present teachings, or modify equivalent embodiments to equivalent variations, without departing from the scope of the present teachings, using the methods and techniques disclosed above. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are within the scope of the technical solution of the present invention, unless the technical essence of the present invention is not departed from the content of the technical solution of the present invention.

Claims

1. A transconductance amplifier circuit, comprising: the current source circuit comprises transconductance impedance, a differential pair, a negative feedback branch, a mirror image output branch, an adjustable tail current source, a first bias current source and a second bias current source; wherein:

when the difference value changes, the output current of the adjustable tail current source changes, and the negative feedback branch is used for adjusting the output current of the transimpedance, so that the output current of the first output end of the differential pair tends to the current value of the first bias current source, the output current of the second output end of the differential pair tends to the current value of the second bias current source, the voltage at the two ends of the transimpedance is equal to the difference value, and the ratio of the output current of the transimpedance to the difference value is fixed;

2. A transconductance amplifier circuit according to claim 1, wherein said negative feedback branch comprises: a first switch tube; wherein:

the mirror image output branch comprises: a second switching tube; wherein:

the output end of the second switching tube is grounded; the input end of the second switching tube is used as the output end of the transconductance amplifier circuit; the control end of the second switch tube is connected with the second output end of the differential pair;

3. The transconductance amplifier circuit of claim 1, wherein the switching transistors in said negative feedback branch and said mirror output branch are of the same type, the switching transistors in said differential pair are of the same type, and the switching transistors in said negative feedback branch and said mirror output branch are of the opposite type to the switching transistors in said differential pair.

4. The transconductance amplifier circuit of claim 1, further comprising: a tail current regulation branch; wherein:

5. The transconductance amplifier circuit of claim 4, wherein the tail current regulation branch comprises: an integral operation circuit and a current regulation branch circuit; wherein:

the current regulating branch circuit is arranged between the power supply and the ground; the control end of the current regulating branch circuit is connected with the output end of the integral operation circuit; the output end of the current adjusting branch circuit is connected with the control end of the adjustable tail current source;

6. The transconductance amplifier circuit of claim 5, wherein the integrating operational circuit comprises: an operational amplifier, a feedback resistor and a feedback capacitor; wherein:

7. The transconductance amplifier circuit of claim 6, wherein said current regulation branch comprises: a fifth switching tube and a sixth switching tube; wherein:

the control end of the fifth switching tube is used as the control end of the current regulating branch; the input end of the fifth switching tube is connected with the output end and the control end of the sixth switching tube, and the connection point is used as the output end of the current regulating branch.

8. The transconductance amplifier circuit of claim 7, wherein the adjustable tail current source comprises: a seventh switching tube; wherein:

9. A transconductance amplifier circuit according to any one of claims 5-8, further comprising: and the current limiting branch circuit is used for limiting the output current of the transconductance amplifier circuit to be a first threshold value by limiting the output current of the adjustable tail current source to be a second threshold value.

10. A transconductance amplifier circuit according to claim 9, characterized in that said current limiting branch comprises: the device comprises a first mirror image sampling branch, a limiting branch and a reference current source; wherein:

11. The transconductance amplifier circuit of claim 10, wherein said first mirrored sampling branch comprises: an eighth switching tube; wherein:

the limiting branch comprises: a ninth switching tube; wherein:

12. A transconductance amplifier circuit according to any one of claims 1 to 8, further comprising: and the clamping control branch circuit is used for clamping the output current of the transconductance amplifier circuit to be a third threshold value by clamping the output current of the second output end of the differential pair to be the current value of the second bias current source.

13. The transconductance amplifier circuit of claim 12, wherein said clamp control circuit comprises: the second mirror image sampling branch circuit, the subtraction circuit and the clamping branch circuit; wherein:

14. The transconductance amplifier circuit of claim 13, wherein said second mirrored sampling branch comprises: a tenth switching tube and a divider resistor; wherein:

the clamping branch comprises: an eleventh switching tube; wherein:

15. A power converter, characterized in that an error amplifier of a control system of the power converter is a transconductance amplifier circuit according to any one of claims 1-14.

16. An electronic product comprising the power converter of claim 15.