Transconductance amplifier circuit, power converter and electronic product

Abstract

The present application provides a transconductance amplifier circuit, a power converter, and an electronic product. Since the output of the transconductance amplifier circuit is current, the circuit has a relatively fast response speed when there is no large compensation network in the subsequent stage of its output end. In addition, since the voltage across the transconductance impedance is equal to the difference between the first voltage and the second voltage, the output current of the transconductance impedance flows entirely into the negative feedback branch, and the mirror output branch mirrors the current in the negative feedback branch, the transconductance of the transconductance amplifier circuit is fixed. Therefore, when a subsequent stage compensation network is present in the transconductance amplifier circuit, the influence of the subsequent 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 of the power converter, that is, the transient response performance.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and in particular to a transconductance amplifier circuit, a power converter and an electronic product. Background Art

[0002] Currently, power converter products are widely used as power supply components in various electronic products due to their high conversion efficiency.

[0003] Among them, the error amplifier is an indispensable key part in most power converter control systems. Usually, the error amplifier in the power converter control system will use a voltage operational amplifier, such as Figure 1 A typical voltage operational amplifier using type three compensation is shown.

[0004] However, in general, a voltage operational amplifier requires a relatively complex compensation network. 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. Therefore, when the voltage operational amplifier is applied to a power converter, it will affect the transient response performance of the power converter. Summary of the Invention

[0005] In view of this, the present invention provides a transconductance amplifier circuit, a power converter, and an electronic product to improve the transient response performance of the power converter.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of the present invention provides a transconductance amplifier circuit, comprising: a transconductance impedance, a differential pair, a negative feedback branch, a mirror output branch, an adjustable tail current source, and a first bias current source and a second bias current source; wherein:

[0008] The two receiving ends of the differential pair receive a first voltage and a second voltage respectively;

[0009] The first output terminal of the differential pair is grounded through the first bias current source, and the second output terminal 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;

[0010] The second input end of the differential pair is connected to the first input end of the differential pair through the transconductance impedance, and the connection point is connected to the power supply through the adjustable tail current source; the difference between the output current of the adjustable tail current source and the first voltage and the second voltage satisfies a preset relationship;

[0011] The collection end of the negative feedback branch is connected to the second output end of the differential pair, and the feedback end of the negative feedback branch is connected to the second input end of the differential pair;

[0012] When the difference changes, the output current of the adjustable tail current source changes, and the negative feedback branch is used to adjust 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, resulting in the voltage across the transconductance impedance being equal to the difference, and the ratio of the output current of the transconductance impedance to the difference being fixed;

[0013] The proportion of the output current of the transconductance impedance that ultimately flows into the feedback end of the negative feedback branch exceeds a preset ratio, so that when the difference changes, the ratio of the current in the negative feedback branch to the difference remains constant;

[0014] The mirror output branch is used to perform mirror ratio replication of the current in the negative feedback branch at a first preset ratio and use it as the output current of the transconductance amplifier circuit, so that the transconductance of the transconductance amplifier circuit is fixed when the difference changes.

[0015] Optionally, the negative feedback branch includes: a first switch tube; wherein:

[0016] The output end of the first switch tube is grounded, the input end of the first switch tube serves as the feedback end of the negative feedback branch, and the control end of the first switch tube serves as the collection end of the negative feedback branch;

[0017] The mirror output branch includes: a second switch tube; wherein:

[0018] The output end of the second switch tube is grounded; the input end of the second switch tube serves as the output end of the transconductance amplifier circuit; and the control end of the second switch tube is connected to the second output end of the differential pair;

[0019] The differential pair includes a third switch tube and a fourth switch tube; wherein:

[0020] The input end of the third switch tube serves as the first input end of the differential pair, the output end of the third switch tube serves as the first output end of the differential pair, and the control end of the third switch tube serves as the first control end of the differential pair;

[0021] The input end of the fourth switch tube serves as the second input end of the differential pair, the output end of the fourth switch tube serves as the second output end of the differential pair, and the control end of the fourth switch tube serves as the second control end of the differential pair.

[0022] Optionally, the types of switch tubes in the negative feedback branch and the mirror output branch are the same, the types of switch tubes in the differential pair are the same, and the types of switch tubes in the negative feedback branch and the mirror output branch are opposite to the types of switch tubes in the differential pair.

[0023] Optionally, it further includes: a tail current regulating branch; wherein:

[0024] The sampling end of the tail current regulating branch is connected to the first output end of the differential pair, and the output end of the tail current regulating branch is connected to the control end of the adjustable tail current source;

[0025] The tail current regulating branch is used to increase the output current of the adjustable tail current source when the output current of the first output end of the differential pair is less than the current value of the first current source, so that the output current of the adjustable tail current source and the difference satisfy a preset relationship.

[0026] Optionally, the tail current regulating branch includes: an integral operation circuit and a current regulating branch; wherein:

[0027] The current regulating branch is arranged between the power supply and the ground; the control end of the current regulating branch is connected to the output end of the integral operation circuit; the output end of the current regulating branch is connected to the control end of the adjustable tail current source;

[0028] The integral operation circuit is configured to control the current regulation branch to reduce the output current of the adjustable tail current source when the voltage at the first output terminal of the differential pair is greater than a first reference voltage; and to control the current regulation branch to increase the output current of the adjustable tail current source when the voltage at the first output terminal of the differential pair is less than the first reference voltage;

[0029] The first reference voltage is the voltage at the first output end of the differential pair when the output current of the first output end of the differential pair is equal to the current value of the first bias current source.

[0030] Optionally, the integration operation circuit includes: an operational amplifier, a feedback resistor, and a feedback capacitor; wherein:

[0031] The non-inverting input terminal of the operational amplifier receives the first reference voltage, the inverting input terminal of the operational amplifier receives the voltage of the first output terminal of the differential pair, and the output terminal of the operational amplifier serves as the output terminal of the integration operation circuit;

[0032] The feedback capacitor and the feedback resistor are connected in series between the output terminal of the operational amplifier and the inverting input terminal of the operational amplifier.

[0033] Optionally, the current regulating branch includes: a fifth switch tube and a sixth switch tube; wherein:

[0034] The output end of the fifth switch tube is grounded, and the input end of the sixth switch tube is connected to the power supply;

[0035] The control end of the fifth switch tube serves as the control end of the current regulating branch; the input end of the fifth switch tube is connected to the output end and the control end of the sixth switch tube, and the connection point serves as the output end of the current regulating branch.

[0036] Optionally, the adjustable tail current source includes: a seventh switch tube; wherein:

[0037] The input end of the seventh switch tube serves as the input end of the adjustable tail current source; the output end of the seventh switch tube serves as the output end of the adjustable tail current source; and the control end of the seventh switch tube serves as the control end of the adjustable tail current source;

[0038] The seventh switching tube is used to perform a mirror output of the current in the sixth switching tube at a second preset ratio.

[0039] Optionally, it further includes: a current limiting branch, used to limit the output current of the transconductance amplifier circuit to a first threshold by limiting the output current of the adjustable tail current source to a second threshold.

[0040] Optionally, the current limiting branch includes: a first mirror sampling branch, a limiting branch and a reference current source; wherein:

[0041] The first mirror sampling branch and the reference current source are arranged in series between the power supply and the ground; the first mirror sampling branch is used to sample the output current of the adjustable tail current source at a third preset ratio and mirror-copy the current in the current regulating branch at a fourth preset ratio, and use the mirrored current as the first sampled current;

[0042] The limiting branch is configured to limit the output current of the adjustable tail current source to the second threshold by limiting the output current of the first output terminal of the differential pair to the current value of the first bias current source when the first sampling current is greater than or equal to the current value of the reference current source;

[0043] The current value of the reference current source is equal to the product of the third preset ratio and the second threshold.

[0044] Optionally, the first mirror sampling branch includes: an eighth switch tube; wherein:

[0045] The input end of the eighth switch tube is connected to the power supply, the output end of the eighth switch tube is connected to the input end of the reference current source, and the control end of the eighth switch tube is connected to the output end of the tail current regulation branch;

[0046] The eighth switch tube is used to mirror the current in the current regulating branch at a fourth preset ratio;

[0047] The limiting branch includes: a ninth switch tube; wherein:

[0048] The output end of the ninth switch tube is connected to the first output end of the differential pair, the input end of the ninth switch tube is connected to the power supply, and the control end of the ninth switch tube is connected to the output end of the first mirror sampling branch.

[0049] Optionally, it further includes: a clamping control branch, used to clamp the output current of the transconductance amplifier circuit to a third threshold by clamping the output current of the second output end of the differential pair to the current value of the second bias current source.

[0050] Optionally, the clamping control circuit includes: a second mirror sampling branch, a subtraction circuit, and a clamping branch; wherein:

[0051] The second mirror sampling branch is used to mirror the output current of the transconductance amplifier circuit at a fifth preset ratio and convert it into a sampled voltage output;

[0052] The subtraction circuit has a non-inverting input terminal receiving the sampled voltage and an inverting input terminal receiving a second reference voltage, and the subtraction circuit is configured to output a clamping signal when the sampled voltage is greater than the second reference voltage; the second reference voltage is the voltage at the output terminal of the second sampling branch when the current in the second mirror sampling branch is equal to the product of the fifth preset ratio and the third threshold value;

[0053] The clamping branch is configured to clamp the output current of the second output end of the differential pair to a current value of the second bias current source when receiving the clamping signal.

[0054] Optionally, the second mirror sampling branch includes: a tenth switch tube and a voltage divider resistor; wherein:

[0055] The input end of the tenth switching tube is connected to the power supply via the voltage-dividing resistor, the output end of the tenth switching tube is grounded, the control end of the tenth switching tube serves as the sampling end of the second mirror sampling branch, and the connection point between the tenth switching tube and the voltage-dividing resistor serves as the output end of the second mirror sampling branch;

[0056] The clamping branch includes: an eleventh switching tube; wherein:

[0057] The output end of the eleventh switch tube is connected to the second output end of the differential pair, the input end of the eleventh switch tube is connected to the power supply, and the control end of the eleventh switch tube is connected to the output end of the subtraction circuit.

[0058] A second aspect of the present invention provides a power converter, wherein the error amplifier of the control system of the power converter is the transconductance amplifier circuit described in any paragraph of the first aspect.

[0059] A third aspect of the present invention provides an electronic product, comprising the power converter described in the second aspect.

[0060] As can be seen from the above technical solution, the present invention provides a transconductance amplifier circuit. Since the output is current, when there is no large compensation network at the output end, the circuit has a relatively fast response speed. In addition, in the transconductance amplifier circuit, when the difference between the first voltage and the second voltage changes, the negative feedback branch adjusts the output current of the transconductance impedance, causing the output current of the adjustable tail current source to change, thereby causing the output current of the first output end of the differential pair to tend to the current of the first bias current source, and the output current of the second output end of the differential pair to tend 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, thereby causing the voltage across the transconductance impedance to be equal to the difference between the first voltage and the second voltage, that is, the transconductance The ratio of the output current of the impedance to the difference is fixed; and, of the output current of the transconductance impedance, the proportion of the current flowing into the feedback end of the negative feedback branch exceeds a preset ratio, so that when the difference between the first voltage and the second voltage changes, the ratio of the current in the negative feedback branch to the difference between the first voltage and the second voltage is fixed; and, the mirror output branch performs a mirror-proportional copy of the current in the negative feedback branch and uses it as the output current of the transconductance amplifier circuit, so that the transconductance of the transconductance amplifier circuit is fixed; therefore, when a post-stage compensation network is present in the transconductance amplifier circuit, 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 of the power converter, that is, the transient response performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0062] Figure 1 It is a typical voltage operational amplifier using a three-type compensation method in the prior art;

[0063] Figure 2-Figure 9 The following are structural schematic diagrams of eight implementation modes of the transconductance amplifier circuit provided in this application. DETAILED DESCRIPTION

[0064] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0065] In this application, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0066] In order to improve the transient response performance of the power converter, the embodiment of the present application provides a transconductance amplifier circuit, the specific structure of which is as follows: Figure 2 As shown, it includes: a transconductance impedance 10, a differential pair 21, a negative feedback branch 22, a mirror output branch 23, an adjustable tail current source Iw, and a first bias current source IB1 and a second bias current source IB2.

[0067] In the transconductance amplifier circuit, two receiving ends of the differential pair 21 receive a first voltage VP and a second voltage VN respectively; a first output end of the differential pair 21 is grounded through a first bias current source IB1 , and a second output end is grounded through a second bias current source IB2 .

[0068] The second input end of the differential pair 21 is connected to the first input end of the differential pair 21 through the transconductance impedance 10, and the connection point is connected to the power supply VIN through the adjustable tail current source Iw. The output current of the adjustable tail current source Iw and the difference between the first voltage VP and the second voltage VN satisfy a preset relationship.

[0069] The collection end of the negative feedback branch 22 is connected to the second output end of the differential pair 21, and the feedback end of the negative feedback branch 22 is connected to the second input end of the differential pair 21; the collection end of the mirror output branch 23 is connected to the collection end of the negative feedback circuit, and the output end of the mirror output branch 23 serves as the output end of the transconductance amplifier circuit.

[0070] In addition, it is also provided that: the current values ​​of the first bias current source IB1 and the second bias current source IB2 are equal; among the output current of the transconductance impedance 10, the proportion of the current that ultimately flows into the feedback end of the negative feedback branch 22 exceeds a 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, among the output current of the transconductance impedance 10, the proportion of the current that flows into the feedback end of the feedback branch exceeds the preset ratio.

[0071] The preset ratio is a preset ratio at which the current flowing into the second input terminal of the differential pair 21 can be ignored in actual applications, that is, a preset ratio at which the current value of the second bias current source IB2 can be ignored in actual applications.

[0072] It should be noted that, in practical applications, the current value of the second bias current source IB2 can be set to a minimum value, that is, the current value of the second bias current source IB2 is much smaller than the current flowing into the negative feedback branch 22, so that the proportion of the output current of the transconductance impedance 10 that ultimately flows into the feedback end of the negative feedback branch 22 exceeds a preset ratio.

[0073] 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 end of the differential pair 21 and the current value of the first bias current source IB1, as well as the magnitude relationship between the output current of the second output end of the differential pair 21 and the current value of the second bias current source IB2, both change, thereby causing the negative feedback branch 22 to adjust the output current of the transconductance impedance 10 and the output current of the adjustable tail current source Iw to change, thereby causing the output current of the first output end 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 end to tend to the current value of the second bias current source IB2.

[0074] Optionally, the difference between the first voltage VP and the second voltage VN changes, which may be the first voltage VP changing, or the second voltage VN changing, or both changing at the same time. No specific limitation is made here, and all are within the scope of protection of this application.

[0075] Since the current values ​​of the first bias current source IB1 and the second bias current source IB2 are equal, Kirchhoff's voltage law deduces that the voltage across the transconductance impedance 10 is equal to the difference between the first voltage VP and the second voltage VN. Furthermore, as can be seen from the above, the output current of the transconductance impedance 10 can be approximately considered to flow entirely into the negative feedback branch 22. Therefore, 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, which is the inverse of the transconductance impedance value.

[0076] The mirror output branch 23 is used to perform mirror-proportional replication of the circuit in the negative feedback branch 22, and use the proportionally replicated current as the output current IGM of the transconductance amplifier circuit. Therefore, the ratio of the output current IGM of the transconductance amplifier circuit to the difference between the first voltage VP and the second voltage VN is fixed, that is, the transconductance of the transconductance amplifier circuit is fixed. The ratio of the mirror replication of the mirror output branch 23 is set to a first preset ratio, and the transconductance of the transconductance amplifier circuit is the product of the inverse of the transconductance impedance value and the first preset ratio.

[0077] As can be seen from the above technical solution, the transconductance of the exaggerated amplifier circuit is fixed, so when a post-stage compensation network is present in the transconductance amplifier circuit, 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 itself is current, when there is no large post-stage compensation network at its output end, the circuit itself also has a faster response speed. Therefore, the transconductance amplifier circuit can improve the response speed of the power converter, that is, the transient response performance.

[0078] It is worth noting that in the prior art, for example, Figure 1 In the voltage operational amplifier shown, the output node of the voltage operational amplifier has a slow conversion speed for large signals due to the influence of the external compensation network. Therefore, if the small-signal bandwidth of the system compensation is to be achieved with a higher specification, the overall cost will be high. However, the transconductance amplifier circuit provided in this embodiment can increase the conversion speed of the output node for large signals, thereby reducing the overall cost required to achieve a higher specification of the small-signal bandwidth of the system compensation.

[0079] On the other hand, this embodiment also provides a specific implementation of the differential pair 21, whose specific structure is as follows: Figure 2 As shown, it includes: a third switch tube M3 and a fourth switch tube M4.

[0080] The input end of the third switch tube M3 serves as the first input end of the differential pair 21, the output end of the third switch tube M3 serves as the first output end of the differential pair 21, and the control end of the third switch tube M3 serves as the first receiving end of the differential pair 21; the input end of the fourth switch tube M4 serves as the second input end of the differential pair 21, the output end of the fourth switch tube M4 serves as the second output end of the differential pair 21, and the control end of the fourth switch tube M4 serves as the second receiving end of the differential pair 21.

[0081] The third switch tube M3 and the fourth switch tube M4 are of the same type. Preferably, Figure 2 As shown, the third switch tube M3 and the fourth switch tube M4 are both PMOS transistors.

[0082] It should be noted that, in practical applications, other implementations are not excluded. For example, the third switch tube M3 and the fourth switch tube M4 are both NMOS transistors. This is not specifically limited here and can be determined according to specific circumstances. All of these are within the scope of protection of this application. However, it should be noted that the types of the third switch tube M3 and the fourth switch tube M4 need to be opposite to the types of the first switch tube M1 and the second switch tube M2.

[0083] On the other hand, this embodiment also provides a specific implementation of the negative feedback branch 22, and its specific structure is as follows: Figure 2 As shown, it includes: a first switch tube M1.

[0084] 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 collection end of the negative feedback branch 22 .

[0085] Preferably, Figure 2 As shown, the first switch tube M1 is an NMOS transistor. In practical applications, including but not limited to this embodiment, for example, the first switch tube M1 can be a PMOS transistor. This is not specifically limited here and can be determined according to specific circumstances, all within the scope of protection of this application.

[0086] The above is only a preferred implementation of the negative feedback branch 22. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application.

[0087] On the other hand, this embodiment also provides a specific implementation of the mirror output branch 23, and its specific structure is as follows: Figure 2 As shown, it includes: a second switch tube M2.

[0088] The output end of the second switch tube M2 is grounded; the input end of the second switch tube M2 serves as the output end of the mirror output branch 23 and also as the output end of the transconductance amplifier circuit; the control end of the second switch tube M2 serves as the collection end of the mirror output branch 23 and is connected to the second output end of the differential pair 21.

[0089] It should be noted that the second switch tube M2 needs to be used in conjunction with the first switch tube M1, so it 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, then Figure 2 As shown, 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.

[0090] The above-mentioned second switch tube M2 being an NMOS transistor is only a preferred embodiment of itself. In practical applications, including but not limited to the above-mentioned embodiments, for example, the second switch tube M2 can be a PMOS transistor. This is not specifically limited here and can be determined according to specific circumstances. All of these are within the scope of protection of this application. However, it should be noted that the type of the second switch tube M2 needs to be the same as that of the first switch tube M1.

[0091] The above is only a preferred implementation of the mirror output branch 23. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to the specific situation. All of them are within the scope of protection of this application.

[0092] Another embodiment of the present application provides a transconductance amplifier circuit. Based on the transconductance amplifier circuit in the above embodiment, its specific structure is as follows: Figure 3 As shown, it also includes: a tail current regulating branch 30.

[0093] The sampling terminal of the tail current regulating branch 30 is connected to the first output terminal of the differential pair 21 , and the output terminal of the tail current regulating branch 30 is connected to the control terminal of the adjustable tail current source Iw.

[0094] When the output current of the first output end of the differential pair 21 is less than the current value of the first current source, the tail current regulation 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 less than the current value of the first current source, the tail current source regulation branch reduces the output current of the adjustable tail current source Iw; thereby achieving a preset relationship between the output current of the adjustable tail current source Iw and the difference between the first voltage VP and the second voltage VN.

[0095] Specifically, under the above regulation mode, an implementation method of the tail current regulation branch 30 is as follows: Figure 4 As shown, it includes: an integration operation circuit 31 and a current regulation branch 32.

[0096] The inverting input terminal of the integration operation circuit 31 serves as the sampling terminal of the tail current regulation branch 30 and is connected to the first output terminal of the differential pair 21; the non-inverting input terminal of the integration operation circuit 31 receives the first reference voltage VREF1; the output terminal of the integration operation circuit 31 is connected to the control terminal of the current regulation branch 32; the output terminal of the current regulation branch 32 is connected to the control terminal of the adjustable tail current source Iw; the current regulation branch 32 is arranged between the power supply VIN and the ground; and the first reference voltage VREF1 is also set to 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 IB1.

[0097] When the output current of the first output end of the differential pair 21 is greater than the current value of the first bias current source IB1, the voltage of the first output end of the differential pair 21 is greater than the first reference voltage VREF1. When the output current of the first output end of the differential pair 21 is less than the current value of the first bias current source IB1, the voltage of the first output end of the differential pair 21 is less than the first reference voltage VREF1.

[0098] When the integral operation circuit 31 determines that the voltage at the first output end of the differential pair 21 is greater than the first reference voltage VREF1, the control current regulation branch 32 reduces the output current of the adjustable tail current source Iw; when the integral operation circuit 31 determines that the voltage at the first output end of the differential pair 21 is less than the first reference voltage VREF1, the control current regulation branch 32 increases the output current of the adjustable tail current source Iw.

[0099] The above is only a preferred implementation of the tail current regulating branch 30. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application.

[0100] On the other hand, this embodiment also provides an implementation of the integral operation circuit 31, whose specific structure is as follows: Figure 4 As shown, it includes: an operational amplifier OP, a feedback resistor Rn and a feedback capacitor C.

[0101] The non-inverting input terminal of the operational amplifier OP serves as the non-inverting input terminal of the integration operation circuit 31, and the inverting input terminal of the operational amplifier OP serves as the inverting input terminal of the integration operation circuit 31; the output terminal of the operational amplifier OP serves as the output terminal of the integration 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 achieve stability compensation of the tail current regulation branch 30.

[0102] The above is only a preferred implementation of the integration operation circuit 31. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances. All of them are within the scope of protection of this application.

[0103] On the other hand, this embodiment also provides an implementation of the current regulating branch 32, and its specific structure is as follows: Figure 4 As shown, it includes: a fifth switch tube M5 and a sixth switch tube M6.

[0104] The output end of the fifth switch tube M5 is grounded, and the input end of the sixth switch tube M6 is connected to the power supply VIN; the control end of the fifth switch tube M5 serves as the control end of the current regulation branch 32; the input end of the fifth switch tube M5 is connected to the output end and the control end of the sixth switch tube M6, and the connection point serves as the output end of the current regulation branch 32.

[0105] Preferably, Figure 4 As shown, the fifth switch tube M5 is an NMOS transistor and the sixth switch tube M6 is a PMOS transistor. In practical applications, including but not limited to this implementation, no specific limitation is made here and it can be determined according to the specific situation, all of which are within the scope of protection of this application.

[0106] The above is only a preferred implementation of the current regulating branch 32. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application.

[0107] On the other hand, this embodiment provides an implementation of an adjustable tail current source Iw to adapt to the adjustment of the tail current adjustment branch 30 itself. The specific structure of this implementation of the adjustable tail current source Iw is as follows: Figure 5 As shown, it includes: a seventh switch tube M7.

[0108] The input end of the seventh switch tube M7 serves as the input end of the adjustable tail current source Iw; the output end of the seventh switch tube M7 serves as the output end of the adjustable tail current source Iw; and the control end of the seventh switch tube M7 serves as the control end of the adjustable tail current source Iw; wherein the seventh switch tube M7 mirrors the current in the sixth switch tube M6 at a second preset ratio.

[0109] Preferably, Figure 5 As shown, the seventh switch tube M7 is a PMOS transistor. In practical applications, including but not limited to this embodiment, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application. It should be noted that the seventh switch tube M7 needs to use the same type of transistor as the sixth switch tube M6.

[0110] The above is only a preferred implementation of the adjustable tail current source Iw. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to the specific situation, all of which are within the scope of protection of this application.

[0111] Below Figure 5 Taking the transconductance amplifier circuit shown in FIG. 1 as an example, the adjustment process of the transconductance amplifier circuit after its input signal changes is described. The adjustment process is specifically as follows:

[0112] When the first voltage VP remains unchanged and the second voltage VN jumps downward, the gate-source voltage of the fourth switch tube M4 increases, and the current in the fourth switch tube M4 increases and becomes greater than the power supply value of the second bias current source IB2. That is, the output current of the second output end of the differential pair 21 increases and becomes greater than the power supply value of the second bias current source IB2. At the same time, because the current in the seventh switch tube M7 has not yet been adjusted, the seventh switch tube M7 cannot meet the current requirements of its own downstream branches, causing the current in the third switch tube M3 to be less than the power supply value of the first bias current source IB1. That is, the voltage at the first output end of the differential pair 21 drops and becomes lower than the first reference voltage VREF1. As a result, the gate-source voltage of the fifth switch tube M5 increases, and the current increases, which in turn causes the sixth switch tube M6 to The current of the seventh switch tube M7 increases, thereby increasing the current of the seventh switch tube M7. When the current of the seventh switch tube M7 can meet the circuit requirements of the branches below it, the tail current regulation branch 30 completes the amplification regulation. Finally, the transconductance amplifier circuit tends to be stable again, that is, the current of the third switch tube M3 tends to the current value of the first bias current source IB1, and the current of the fourth switch tube M4 tends to the current value of the second bias current source IB2. After the transconductance amplifier circuit tends to be stable again, since the current of the fourth switch tube M4 increases compared with before, the current of the first switch tube M1 also increases compared with before, and thus the current of the second switch tube M2 increases compared with before, that is, the output current IGM of the transconductance amplifier circuit increases compared with before.

[0113] When the first voltage VP remains unchanged and the second voltage VN jumps upward, the gate-source voltage of the fourth switch tube M4 decreases, and the current decreases and becomes less 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 becomes less than the power supply value of the second bias current source IB2. At the same time, because the current of the seventh switch tube M7 has not yet been adjusted, the current of the seventh switch tube M7 is greater than the current demand of its own downstream branches, which causes the current of the third switch tube M3 to be greater than the power supply value of the first bias current source IB1. That is, the voltage of the first output terminal of the differential pair 21 increases. The voltage increases to and exceeds the first reference voltage VREF1, thereby causing the gate-source voltage of the fifth switch M5 to drop, reducing the current, and thus increasing the current of the sixth switch M6. Consequently, the current of the seventh switch M7 decreases until the current of the seventh switch M7 just meets the circuit requirements of the branches below it. The tail current regulation branch 30 completes the reduction regulation. Finally, the transconductance amplifier circuit stabilizes again, i.e., the current of the third switch M3 approaches the current value of the first bias current source IB1, and the current of the fourth switch M4 approaches the current value of the second bias current source IB2. After the transconductance amplifier circuit stabilizes again, since the current of the fourth switch M4 decreases compared to before, the current of the first switch M1 also decreases compared to before, causing the current of the second switch M2 to decrease compared to before. In other words, the output current IGM of the transconductance amplifier circuit decreases compared to before.

[0114] It can be seen that after the transconductance amplifier circuit tends to stabilize, the current in the third switch tube M3 is equal to the current value of the first bias current source IB1, and the current in the fourth switch tube M4 is equal to the current value of the second bias current source IB2. Therefore, the voltage Vo across the transconductance impedance 10 is equal to VP+VSG_M3-VN-VSG_M4; where VP is the first voltage, VN is the second voltage, VSG_M3 is the gate-source voltage of the third switch tube M3, and VSG_M4 is the gate-source voltage of the fourth switch tube M4.

[0115] 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 in the third switch tube M3 is equal to the current in the fourth switch tube M4. Therefore, the gate-source voltage VSG_M3 of the third switch tube M3 is equal to the gate-source voltage VSG_M4 of the fourth switch tube M4. That is, the voltage across the transconductance impedance 10 Vo=VP-VN. Since the voltage across the transconductance impedance 10 can also be expressed as: Vo=Io*Ro, VP-VN=Io*Ro, where Io is the current in the transconductance impedance 10 and Ro is the resistance of the transconductance impedance 10.

[0116] 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 approximately considered to flow entirely into the first switch M1, the transconductance GMo of the output of the differential pair 21 with respect to the first switch M1 is GMo=Io / (VP-VN). Further, substituting VP-VN=Io*Ro into the equation, we obtain GMo=1 / Ro. Therefore, the transconductance GM of the transconductance amplifier circuit is IGM / (VP-VN)=k*Io / (VP-VN)=k / Ro, where IGM is the output current of the transconductance amplifier circuit and k is the first predetermined ratio.

[0117] In summary, the transconductance GM of the transconductance amplifier is related to the transconductance impedance 10 and the mirror image ratio of the second switch M2 and the first switch M1, and is unrelated to the differential pair 21 and the operating point voltage. Therefore, after the transconductance impedance 10 is set, the transconductance of the transconductance amplifier circuit is fixed.

[0118] In the above embodiment, the transconductance amplifier circuit can adjust the current value of the adjustable tail current source Iw through the tail current adjustment branch 30. However, if the current value of the adjustable tail current source Iw is adjusted to a very large value, it may cause damage to itself or other devices in the transconductance amplifier circuit. In order to avoid damage to the adjustable tail current source Iw or other devices in the transconductance amplifier circuit, another embodiment of the present application provides another implementation of the transconductance amplifier circuit. On the basis of the transconductance amplifier circuit provided in the above embodiment, it also includes: a current limiting branch 40. The current limiting branch 40 limits the output current IGM of the transconductance amplifier circuit to a first threshold by limiting the output current of the adjustable tail current source Iw to a second threshold.

[0119] Specifically, a connection relationship between the current limiting branch 40 and other branches is as follows: Figure 6 As shown, specifically:

[0120] A sampling terminal of the current limiting branch 40 is connected to a control terminal of the adjustable tail current source Iw, and an output terminal of the current limiting branch 40 is connected to a first output terminal of the differential pair 21 .

[0121] 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 end of the differential pair 21, so that the output current of the first output end of the differential pair 21 is equal to the current value of the first bias current source IB1, so that the tail current adjustment branch 30 no longer adjusts the current value of the adjustable tail current source Iw, 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 less than the second threshold, the current limiting branch 40 does not limit the output current of the first output end of the differential pair 21, that is, it does not affect the normal operation of the tail current adjustment branch 30.

[0122] The ratio of the output current of the adjustable tail current source Iw to the output current IGM of the transconductance amplifier circuit is equal to the ratio of the first threshold to the second threshold.

[0123] The above is only a preferred connection relationship of the current limiting branch 40. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application.

[0124] On the other hand, this embodiment provides a specific implementation of the current limiting branch 40, and its specific structure is as follows: Figure 7 As shown, it includes: a first mirror sampling branch 41, a limiting branch 42 and a reference current source IR.

[0125] The first mirror sampling branch 41 and the reference current source IR are arranged in series between the power supply VIN and the ground. The sampling end of the first mirror sampling branch 41 serves as the sampling end of the current limiting branch 40. In addition, the first mirror sampling branch 41 samples the output current of the adjustable tail current source Iw at a third preset ratio and mirrors the current in the current regulating branch 30 at a fourth preset ratio, and uses the mirrored current as the first sampled current.

[0126] A sampling end of the limiting branch 42 is connected to a connection point between the first mirror sampling branch 41 and the reference current source IR, and an output end of the limiting branch 42 serves as an output end of the current limiting branch 40 .

[0127] 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 a second threshold by limiting the output current of the first output end of the differential pair 21 to the current value of the first bias current source IB1; when the first sampling current is less than the current value of the reference current source IR, the limiting branch 42 does not affect the normal operation of the tail current adjustment branch 30.

[0128] The current value of the reference current source IR is equal to the product of the third preset ratio and the second threshold.

[0129] 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 greater than or equal to the second threshold. Therefore, this embodiment can achieve the above function.

[0130] The above is only a preferred implementation of the current limiting branch 40. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application.

[0131] On the other hand, this embodiment also provides a specific implementation of the first mirror sampling branch 41, and its specific structure is as follows: Figure 7 As shown, it includes: an eighth switching tube M8.

[0132] An input end of the eighth switch tube M8 is connected to the power supply VIN, an output end of the eighth switch tube M8 is connected to the input end of the reference current source IR, and a control end of the eighth switch tube M8 serves as a sampling end of the first mirror sampling branch 41; wherein, the eighth switch tube M8 performs a mirror copy of the current in the current regulation branch 30 at a fourth preset ratio.

[0133] Preferably, Figure 7 As shown, the eighth switch tube M8 is a PMOS transistor. In practical applications, other implementations are not excluded and are not specifically limited here. They can be determined according to specific circumstances and are all within the scope of protection of this application.

[0134] It should be noted that the eighth switch M8 needs to be the same type of transistor as the sixth switch M6 and the seventh switch M7, and the mirror ratio of the eighth switch M8 and the seventh switch M7 is equal to the third preset ratio.

[0135] On the other hand, this embodiment also provides a specific implementation of the limiting branch 42, and its specific structure is as follows: Figure 7 As shown, it includes: a ninth switch tube M9.

[0136] The output end of the ninth switch tube M9 serves as the output end of the limiting branch 42 ; the input end of the ninth switch tube M9 is connected to the power supply VIN; and the control end of the ninth switch tube M9 serves as the sampling end of the limiting branch 42 .

[0137] It should be noted that, in this embodiment of the limiting branch 42, to ensure that the ninth switch tube M9 can be turned on when the first sampling current is greater than or equal to the current value of the reference current source IR, the turn-on threshold of the ninth switch tube M9 is set to the voltage at the connection point between the first mirror 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.

[0138] Preferably, Figure 7 As shown, the ninth switch tube M9 is an NMOS transistor. In practical applications, other implementations are not excluded and are not specifically limited here. They can be determined according to specific circumstances and are all within the protection scope of this application.

[0139] It should be noted that the maximum output current of the transconductance amplifier circuit is limited by sampling the current value of the adjustable tail current source Iw and comparing it with the reference current, which also makes the limitation of the output current IGM of the transconductance amplifier circuit more accurate.

[0140] Below is Figure 7 Taking the transconductance amplifier circuit shown in FIG. 1 as an example, the working process of the current limiting branch 40 is described as follows:

[0141] The eighth switch M8 mirrors the current of the seventh switch M7 at a third preset ratio. When the current of the seventh switch M7 is less than the second threshold, the current of the eighth switch M8 is less than the current value of the reference current source IR. That is, the voltage at the connection point between the eighth switch M8 and the reference current source IR is less than the turn-on threshold of the ninth switch M9. The ninth switch M9 is turned off, and the normal operation of the tail current regulation branch 30 is not affected.

[0142] When the current in the seventh switch tube M7 is greater than or equal to the second threshold, the current in the eighth switch 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 switch tube M8 and the reference current source IR is greater than the conduction threshold of the ninth switch tube M9. The ninth switch tube M9 is turned on and injects current into the connection point between the first output terminal of the differential pair 21 and the first bias current source IB1, so that the voltage at the first output terminal of the differential pair 21 stops decreasing and remains stable. Even if the output current at the first output terminal of the differential pair 21 stops decreasing and remains stable, the current in the fifth switch tube M5 stops increasing and remains stable, thereby causing the current in the seventh switch tube M7 to stop increasing and remain at the second threshold.

[0143] At this time, the current on the seventh switch tube M7 no longer increases, so when the current on the fourth switch tube M4 is equal to the current value of the second bias current source IB2, that is, when the transconductance amplifier circuit tends to be stable, the output current IGM of the transconductance amplifier circuit is limited to the first threshold.

[0144] Among them, the first threshold is:

[0145] Since the current values ​​of the first bias current source IB1 and the second bias current source IB2 are the same, based on the approximate assumption that the output current of the transconductance impedance 10 flows entirely into the first switch tube M1, it can also be approximated that the output current of the adjustable tail current source Iw flows entirely only into the first switch tube M1 across the transconductance impedance 10, that is, the current in the first switch tube M1 is equal to the output current of the adjustable tail current source Iw, so the first threshold value I1=k*I2=k*Iref1 / k1; wherein I2 is the second threshold value, k is the first preset ratio, k1 is the third preset ratio, and Iref1 is the current value of the reference current source IR.

[0146] 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, that is, the maximum output current value of the transconductance amplifier circuit. In addition, after the current limiting branch 40 is provided in the transconductance amplifier circuit, since the voltages across the transconductance are both at relatively low values ​​from normal operation of the transconductance amplifier circuit to current limiting, in a power converter with low precision requirements, the input offset generated by the transconductance impedance 10 provided at the source end of one of the switches in the differential pair 21 can be ignored. When the design offset is large, the system can reduce the transient jump settling time due to the offset, thereby achieving better transient response.

[0147] In the above embodiment, the transconductance amplifier circuit can adjust the current value of the adjustable tail current source Iw through the tail current adjustment branch 30. However, if the current value of the adjustable tail current source Iw is adjusted to a very small value, the output current IGM of the transconductance amplifier circuit may be affected. That is, at this time, there is a large error in the output current IGM output by the transconductance amplifier circuit. To avoid this phenomenon, another embodiment of the present application provides another implementation of the transconductance amplifier circuit, and its specific structure is as follows: Figure 8 As shown, based on the transconductance amplifier circuit provided in the above embodiment, it further includes: a clamping control branch 50.

[0148] The sampling end of the clamp control branch 50 is connected to the second output end of the differential pair 21 , and the output end of the clamp control branch 50 is connected to the second output end of the differential pair 21 .

[0149] When the output current of the second output end of the differential pair 21 is less than the fourth threshold, the output current IGM of the transconductance amplifier circuit is clamped to the third threshold by clamping the output current of the second output end of the differential pair 21 to the current value of the second bias current source IB2 through the clamp control branch 50.

[0150] The ratio of the third threshold to the fourth threshold is equal to the first preset ratio.

[0151] On the other hand, this embodiment provides a specific implementation of the clamping control circuit, and its specific structure is as follows: Figure 9 As shown, it includes: a second mirror sampling branch 51, a subtraction circuit 52 and a clamping branch 53.

[0152] The sampling end of the second mirror sampling circuit serves as the sampling end of the clamp control circuit, and the output end of the second mirror sampling circuit is connected to the non-inverting input end of the subtraction circuit 52. In addition, the second mirror sampling circuit mirrors the output current IGM of the transconductance amplifier circuit at a fifth preset ratio and converts it into a sampled voltage output.

[0153] The inverting input terminal of the subtraction circuit 52 receives the second reference voltage Vref2 , wherein the second reference voltage Vref2 is the voltage at the output terminal of the second sampling branch when the current in the second mirror sampling branch is equal to the product of the fifth preset ratio and the third threshold.

[0154] The control end of the clamping branch 53 is connected to the output end of the subtraction circuit 52 , and the output end of the clamping branch 53 serves as the output end of the clamping control circuit.

[0155] 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 .

[0156] Optionally, the subtraction circuit 52 may use an operational amplifier. In practical applications, other implementations are not excluded and are not specifically limited here. They may be determined according to specific circumstances and are all within the scope of protection of this application.

[0157] The above is only a preferred implementation of the clamping control circuit. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application.

[0158] 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 using an operational amplifier for comparison and amplification, which also makes the clamping of the output current IGM of the transconductance amplifier circuit more accurate.

[0159] It is worth noting that, in the prior art, if current limiting and clamping functions are required in a power converter using a voltage operational amplifier, additional circuit modules are required to implement them, which increases the cost and design complexity of the power converter. However, this embodiment, through a multi-loop design, achieves built-in current limiting and clamping functions. It also integrates multiple functions, simplifying the system's modular design. This makes the transconductance amplifier circuit ideally suited for use as a system error amplifier in power converter control systems.

[0160] On the other hand, this embodiment provides a specific implementation of the second mirror sampling branch 51, and its specific structure is as follows: Figure 9 As shown, it includes: a tenth switch tube M10 and a voltage dividing resistor Ra.

[0161] An input end of the tenth switch tube M10 is connected to the power supply VIN through a voltage-dividing resistor Ra. An output end of the tenth switch tube M10 is grounded. A control end of the tenth switch tube M10 serves as a sampling end of the second mirror sampling branch 51. A connection point between the tenth switch tube M10 and the voltage-dividing resistor Ra serves as an output end of the second mirror sampling branch 51.

[0162] The above is only a preferred implementation of the second mirror sampling branch 51. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances. All of them are within the scope of protection of this application.

[0163] On the other hand, this embodiment provides a specific implementation of the clamping branch 53, and its specific structure is as follows: Figure 9 As shown, it includes: an eleventh switch tube M11.

[0164] The output end of the eleventh switch tube M11 serves as the output end of the clamping branch 53 , the input end of the eleventh switch tube M11 is connected to the power supply VIN, and the control end of the eleventh switch tube M11 serves as the control end of the clamping branch 53 .

[0165] The above is only a preferred implementation of the clamping branch 53. In practical applications, including but not limited to the above implementation, no specific limitation is made here and it can be determined according to specific circumstances, all of which are within the scope of protection of this application.

[0166] Below is Figure 9 Taking the transconductance amplifier circuit shown in FIG. 1 as an example, the working process of the clamp control branch 50 is described as follows:

[0167] The tenth switch tube M10 mirrors the current on the second switch tube M2 at a fifth preset ratio. When the voltage at the output end of the tenth switch tube M10 is less than the second reference voltage Vref2, the subtraction circuit 52 controls the eleventh switch tube M11 to be always turned off, without affecting the normal operation of the transconductance amplifier circuit.

[0168] When the voltage at the output terminal of the tenth switch tube M10 is greater than or equal to the second reference voltage Vref2, the subtraction circuit 52 controls the eleventh switch tube M11 to turn on, injecting current into the connection point between the second output terminal of the differential pair 21 and the second bias current source IB2, so that the gate voltage of the first switch tube M1 no longer decreases, thereby preventing the current in the tenth switch tube M10 from decreasing. This achieves the goal of clamping the minimum output current of the transconductance amplifier circuit, and ultimately, the voltage at the output terminal of the tenth switch tube M10 is clamped near the second reference voltage Vref2.

[0169] Since the voltage at the output end of the tenth switch tube M10 is ultimately clamped near the second reference voltage Vref2, the third threshold value I3 = (VIN-Vref2) / Ra / k2, and the fourth threshold value I4 = I3 / k = (VIN-Vref2) / Ra / k2 / k; wherein Vref2 is the second reference voltage, k2 is the fifth preset ratio, k is the first preset ratio, Ra is the voltage divider resistor, and VIN is the power supply voltage.

[0170] 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, ie, the minimum output current value of the transconductance amplifier circuit.

[0171] Another embodiment of the present application provides a power converter, wherein the error amplifier of the control system of the power converter is the transconductance amplifier circuit provided in the above embodiment.

[0172] It should be noted that using the aforementioned open-conductance amplifier circuit as an error amplifier is beneficial for designing a power converter with better transient response performance. Furthermore, if current limiting and clamping functions are required within the power converter, since the transconductance amplifier circuit has a built-in current limiting branch 40 for current limiting and a built-in clamping control branch 50 for current clamping, there is no need to add additional circuit modules to implement these functions, thereby reducing design complexity and cost.

[0173] Another embodiment of the present application provides an electronic product, including the power converter provided by the above embodiment.

[0174] The structure and principle of the power converter can be found in the above embodiments and will not be described in detail again.

[0175] In addition, the electronic product can be any electronic product provided with the above-mentioned power converter, which is not limited here and is within the protection scope of this application.

[0176] For the above description of the disclosed embodiments, the features recorded in the various embodiments in this specification can be replaced or combined with each other, so that professionals in this field can implement or use this application. The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above with a preferred embodiment, it is not used to limit the present invention. Any technician familiar with the field can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A transconductance amplifier circuit, characterized in that: include: transconductance impedance, a differential pair, a negative feedback branch, a mirror output branch, an adjustable tail current source, and a first bias current source and a second bias current source; wherein: The two receiving ends of the differential pair receive a first voltage and a second voltage respectively; The first output terminal of the differential pair is grounded through the first bias current source, and the second output terminal 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 to the first input end of the differential pair through the transconductance impedance, and the connection point is connected to the power supply through the adjustable tail current source; the difference between the output current of the adjustable tail current source and the first voltage and the second voltage satisfies a preset relationship; The collection end of the negative feedback branch is connected to the second output end of the differential pair, and the feedback end of the negative feedback branch is connected to the second input end of the differential pair; When the difference changes, the output current of the adjustable tail current source changes, and the negative feedback branch is used to adjust 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, resulting in the voltage across the transconductance impedance being equal to the difference, and the ratio of the output current of the transconductance impedance to the difference being fixed; The proportion of the output current of the transconductance impedance that ultimately flows into the feedback end of the negative feedback branch exceeds a preset ratio, so that when the difference changes, the ratio of the current in the negative feedback branch to the difference remains constant; The mirror output branch is used to perform mirror ratio replication of the current in the negative feedback branch at a first preset ratio and use it as the output current of the transconductance amplifier circuit, so that the transconductance of the transconductance amplifier circuit is fixed when the difference changes.

2. The transconductance amplifier circuit according to claim 1, wherein: The negative feedback branch includes: a first switch tube; wherein: The output end of the first switch tube is grounded, the input end of the first switch tube serves as the feedback end of the negative feedback branch, and the control end of the first switch tube serves as the collection end of the negative feedback branch; The mirror output branch includes: a second switch tube; wherein: The output end of the second switch tube is grounded; the input end of the second switch tube serves as the output end of the transconductance amplifier circuit; and the control end of the second switch tube is connected to the second output end of the differential pair; The differential pair includes a third switch tube and a fourth switch tube; wherein: The input end of the third switch tube serves as the first input end of the differential pair, the output end of the third switch tube serves as the first output end of the differential pair, and the control end of the third switch tube serves as the first control end of the differential pair; The input end of the fourth switch tube serves as the second input end of the differential pair, the output end of the fourth switch tube serves as the second output end of the differential pair, and the control end of the fourth switch tube serves as the second control end of the differential pair.

3. The transconductance amplifier circuit according to claim 1, wherein: The types of the switch tubes in the negative feedback branch and the mirror output branch are the same, and the types of the switch tubes in the differential pair are the same. In addition, the types of the switch tubes in the negative feedback branch and the mirror output branch are opposite to the types of the switch tubes in the differential pair.

4. The transconductance amplifier circuit according to claim 1, wherein: Also includes: Tail current regulation branch; where: The sampling end of the tail current regulating branch is connected to the first output end of the differential pair, and the output end of the tail current regulating branch is connected to the control end of the adjustable tail current source; The tail current regulating branch is used to increase the output current of the adjustable tail current source when the output current of the first output end of the differential pair is less than the current value of the first bias current source, so that the output current of the adjustable tail current source and the difference satisfy a preset relationship.

5. The transconductance amplifier circuit according to claim 4, wherein: The tail current regulating branch includes: an integral operation circuit and a current regulating branch; wherein: The current regulating branch is arranged between the power supply and the ground; the control end of the current regulating branch is connected to the output end of the integral operation circuit; the output end of the current regulating branch is connected to the control end of the adjustable tail current source; The integral operation circuit is configured to control the current regulation branch to reduce the output current of the adjustable tail current source when the voltage at the first output terminal of the differential pair is greater than a first reference voltage; and to control the current regulation branch to increase the output current of the adjustable tail current source when the voltage at the first output terminal of the differential pair is less than the first reference voltage; The first reference voltage is the voltage at the first output end of the differential pair when the output current of the first output end of the differential pair is equal to the current value of the first bias current source.

6. The transconductance amplifier circuit according to claim 5, wherein: The integration operation circuit includes: an operational amplifier, a feedback resistor and a feedback capacitor; wherein: The non-inverting input terminal of the operational amplifier receives the first reference voltage, the inverting input terminal of the operational amplifier receives the voltage of the first output terminal of the differential pair, and the output terminal of the operational amplifier serves as the output terminal of the integration operation circuit; The feedback capacitor and the feedback resistor are connected in series between the output terminal of the operational amplifier and the inverting input terminal of the operational amplifier.

7. The transconductance amplifier circuit according to claim 6, wherein: The current regulating branch includes: a fifth switch tube and a sixth switch tube; wherein: The output end of the fifth switch tube is grounded, and the input end of the sixth switch tube is connected to the power supply; The control end of the fifth switch tube serves as the control end of the current regulating branch; the input end of the fifth switch tube is connected to the output end and the control end of the sixth switch tube, and the connection point serves as the output end of the current regulating branch.

8. The transconductance amplifier circuit according to claim 7, wherein: The adjustable tail current source includes: a seventh switch tube; wherein: The input end of the seventh switch tube serves as the input end of the adjustable tail current source; the output end of the seventh switch tube serves as the output end of the adjustable tail current source; and the control end of the seventh switch tube serves as the control end of the adjustable tail current source; The seventh switching tube is used to perform a mirror output of the current in the sixth switching tube at a second preset ratio.

9. The transconductance amplifier circuit according to any one of claims 5 to 8, wherein: Also includes: The current limiting branch is configured to limit the output current of the transconductance amplifier circuit to a first threshold by limiting the output current of the adjustable tail current source to a second threshold.

10. The transconductance amplifier circuit according to claim 9, wherein: The current limiting branch includes: a first mirror sampling branch, a limiting branch and a reference current source; wherein: The first mirror sampling branch and the reference current source are arranged in series between the power supply and the ground; the first mirror sampling branch is used to sample the output current of the adjustable tail current source at a third preset ratio and mirror-copy the current in the current regulating branch at a fourth preset ratio, and use the mirrored current as the first sampled current; The limiting branch is configured to limit the output current of the adjustable tail current source to the second threshold by limiting the output current of the first output terminal of the differential pair to the current value of the first bias current source when the first sampling current is greater 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 ratio and the second threshold.

11. The transconductance amplifier circuit according to claim 10, wherein: The first mirror sampling branch includes: an eighth switch tube; wherein: The input end of the eighth switch tube is connected to the power supply, the output end of the eighth switch tube is connected to the input end of the reference current source, and the control end of the eighth switch tube is connected to the output end of the tail current regulation branch; The eighth switch tube is used to mirror the current in the current regulating branch at a fourth preset ratio; The limiting branch includes: a ninth switch tube; wherein: The output end of the ninth switch tube is connected to the first output end of the differential pair, the input end of the ninth switch tube is connected to the power supply, and the control end of the ninth switch tube is connected to the output end of the first mirror sampling branch.

12. The transconductance amplifier circuit according to any one of claims 1 to 8, wherein: Also includes: The clamping control branch is used to clamp the output current of the transconductance amplifier circuit to a third threshold by clamping the output current of the second output end of the differential pair to the current value of the second bias current source.

13. The transconductance amplifier circuit according to claim 12, wherein: The clamping control branch includes: a second mirror sampling branch, a subtraction circuit and a clamping branch; wherein: The second mirror sampling branch is used to mirror the output current of the transconductance amplifier circuit at a fifth preset ratio and convert it into a sampled voltage output; The subtraction circuit has a non-inverting input terminal receiving the sampled voltage and an inverting input terminal receiving a second reference voltage, and the subtraction circuit is configured to output a clamping signal when the sampled voltage is greater than the second reference voltage; the second reference voltage is the voltage at the output terminal of the second mirror sampling branch when the current in the second mirror sampling branch is equal to the product of the fifth preset ratio and the third threshold value; The clamping branch is configured to clamp the output current of the second output end of the differential pair to a current value of the second bias current source when receiving the clamping signal.

14. The transconductance amplifier circuit according to claim 13, wherein: The second mirror sampling branch includes: a tenth switch tube and a voltage divider resistor; wherein: The input end of the tenth switching tube is connected to the power supply via the voltage-dividing resistor, the output end of the tenth switching tube is grounded, the control end of the tenth switching tube serves as the sampling end of the second mirror sampling branch, and the connection point between the tenth switching tube and the voltage-dividing resistor serves as the output end of the second mirror sampling branch; The clamping branch includes: an eleventh switching tube; wherein: The output end of the eleventh switch tube is connected to the second output end of the differential pair, the input end of the eleventh switch tube is connected to the power supply, and the control end of the eleventh switch tube is connected to the output end of the subtraction circuit.

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

16. An electronic product, characterized in that: Including the power converter according to claim 15.

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