Super source follower circuit, super source follower device and amplification circuit

Abstract

The embodiment of the invention discloses a super source follower circuit, a super source follower device and an amplifying circuit, and belongs to the technical field of circuit design verification and emulation.The super source follower circuit comprises an input unit provided with a first input tube and a second input tube, and a feedback unit provided with a first feedback tube and a second feedback tube, the first feedback tube and the second feedback tube are respectively provided with a first signal output end and a second signal output end, the input unit and the feedback unit are connected with the power supply unit through the source electrode resistor, and the power supply unit is used for supplying power. According to the embodiment of the invention, the input voltage is converted into the output current, the transconductance input by the amplification circuit can be determined through the source resistance value by reasonably setting the source resistance and adding the feedback tube, the influence of single tube input on the final equivalent transconductance in the related technology is greatly reduced, the accuracy of the transconductance is increased, and the reliability of the amplification circuit is improved. The problem that the input transconductance of the sub-threshold region is not accurate enough during single-tube input in a simulation model is effectively avoided, and the uncertainty of a chip in a design stage is reduced.

Description

Technical Field

[0001] The embodiments of the present application relate to a super source follower circuit, a device thereof, and an amplifier circuit, and belong to the technical field of circuit design verification and simulation. Background Art

[0002] Amplifier circuits play an important role in the design of integrated circuits. Amplifier circuits are responsible for amplifying input signals, usually amplifying an analog or digital signal because the signal is too small to drive the load, cannot overcome subsequent noise, or cannot provide logic levels for digital circuits.

[0003] The gain of an amplifier directly affects the amplifier's amplification capability. For example, in a switching power supply circuit system, when the amplifier is used as a loop error amplifier, its gain will affect the bandwidth, noise, stability, and transient response of the overall system. Generally, the gain of an amplifier is equal to the transconductance of its input pair multiplied by its output impedance.

[0004] In the switching power supply circuit, the input pair of the loop error amplifier is usually expected to work in the subthreshold region. However, in the device models provided by some process manufacturers, the simulation model parameter gm of a single tube in the subthreshold region cannot be accurately matched with the gm size of the single tube after the actual tape-out, and the gap is large. Usually, the gm after the actual tape-out will be smaller than the gm when simulated using the simulation model. For example, the subthreshold transconductance of the input tube designed in the simulation design stage is 65us, but when tested after the actual tape-out, the transconductance obtained is only 25us. Therefore, if the amplifier circuit is designed only according to the simulation model during chip design, the performance of the chip after the actual tape-out will be worse than that during simulation, and it may even cause the chip to fail to work under ideal conditions.

[0005] In view of the inaccurate gm in the subthreshold region in the above simulation model, there are usually the following solutions: First, increase the size of the input pair tube originally calculated in proportion during design. Although this method can intuitively improve the above problem, it will increase the chip area and thus increase the cost; second, increase the bias current of the input pair tube, but due to the increase in current, the overall power consumption of the chip will inevitably increase. It can be seen that the existing technology can no longer meet people's requirements and needs to be improved urgently. Summary of the invention

[0006] The purpose of the embodiments of the present application is to provide a super source follower circuit, a device thereof, and an amplifier circuit, so as to solve the problems of inaccurate subthreshold transconductance in the simulation model and excessive power consumption of the overall circuit, and to address the shortcomings of the prior art.

[0007] The embodiments of the present application provide the following technical solutions: According to one aspect of an embodiment of the present application, a super source follower circuit is provided, comprising: The input unit is configured to include at least a first input tube and a second input tube, the first input tube has a first signal input end, and the second input tube has a second signal input end; the feedback unit is configured to include at least a first feedback tube and a second feedback tube, the first feedback tube is connected to the first input tube, the first feedback tube has a first signal output end, the second feedback tube is connected to the second input tube, and the second feedback tube has a second signal output end; the power supply unit is connected to the input unit and the feedback unit through a source resistor, and is configured to provide power to the input unit and the feedback unit.

[0008] According to at least one specific implementation of the embodiment of the present application, the source resistor includes a first source resistor and a second source resistor, the first end of the first input tube is the first signal input end, the first signal input end is used to obtain the positive phase part of the input signal, one end of the first source resistor is connected between the second end of the first input tube and the third end of the first feedback tube, and the other end of the first source resistor is connected to the power supply unit; the first end of the second input tube is the second signal input end, the second signal input end is used to obtain the negative phase part of the input signal, the second end of the second input tube is connected to the third end of the second feedback tube, the third end of the second input tube is connected to the first end of the second feedback tube, one end of the second source resistor is connected between the second end of the second input tube and the third end of the second feedback tube, and the other end of the second source resistor is connected to the power supply unit.

[0009] According to at least one specific implementation of the embodiments of the present application, the third end of the first input tube is connected to the first end of the first feedback tube, the second end of the first feedback tube is the first signal output end of the input unit, and the third end of the first feedback tube is connected to the second end of the first input tube.

[0010] According to at least one specific implementation of the embodiment of the present application, the first end of the second feedback tube is connected to the third end of the second input tube, the second end of the second feedback tube is the second signal output end, and the third end of the second feedback tube is connected to the first end of the second input tube.

[0011] According to at least one specific implementation of the embodiment of the present application, it also includes a first compensation capacitor and a second compensation capacitor, one end of the first compensation capacitor is connected between the third end of the first input tube and the first end of the first compensation tube, and the other end is grounded, one end of the second compensation capacitor is connected between the third end of the second input tube and the first end of the second feedback tube, and the other end is grounded.

[0012] According to another aspect of the embodiments of the present application, a super source follower device is provided, and the super source follower device includes the super source follower circuit.

[0013] According to another aspect of the embodiments of the present application, there is provided an amplifier circuit, comprising the super source follower circuit, wherein the super source follower circuit is connected to the amplifier circuit.

[0014] According to at least one specific implementation of the embodiment of the present application, the amplifier circuit is a common-source common-gate amplifier circuit, and the common-source common-gate amplifier circuit includes a third input tube, a fourth input tube, a fifth input tube, a sixth input tube, and: a third feedback tube, a fourth feedback tube, a fifth feedback tube, and a sixth feedback tube, the second end of the third input tube is connected to the second end of the fourth input tube, the first end of the third input tube is connected to the first end of the fourth input tube, and the power supply is connected between the second end of the third input tube and the second end of the fourth input tube; the first end of the fifth input tube is connected to the first end of the sixth input tube, and the second end of the fifth input tube is connected to the The third end of the third input tube is connected to the third end of the third feedback tube, the second end of the sixth input tube is connected to the third end of the fourth input tube, the third end of the fifth input tube is connected to the third end of the third feedback tube, and the third end of the sixth input tube is connected to the third end of the fourth feedback tube; the first end of the third feedback tube is connected to the first end of the fourth feedback tube, the second end of the third feedback tube is connected to the third end of the fifth feedback tube, the second end of the fourth feedback tube is connected to the third end of the sixth feedback tube, the first end of the fifth feedback tube is connected to the first end of the sixth feedback tube, and the second end of the fifth feedback tube is connected to the second end of the sixth feedback tube and then grounded.

[0015] According to at least one specific implementation of the embodiments of the present application, the first signal output end of the input unit is connected between the second end of the third feedback tube and the third end of the fifth feedback tube, and the second signal output end of the input unit is connected between the second end of the fourth feedback tube and the third end of the sixth feedback tube.

[0016] According to at least one specific implementation of the embodiments of the present application, the first input tube, the second input tube, the third input tube, the fourth input tube, the fifth input tube, and the sixth input tube are transistors or MOS tubes, and the first feedback tube, the second feedback tube, the third feedback tube, the fourth feedback tube, the fifth feedback tube, and the sixth feedback tube are transistors or MOS tubes.

[0017] The embodiments of the present application have the following advantages: The input unit in the embodiment of the present application is connected to the feedback unit to convert the input voltage into an output current as the input of the next stage circuit. In this process, by reasonably setting the source resistance and adding the feedback tube, not only can the transconductance of the amplifier circuit input be determined by the source resistance value, but also the influence of the single-tube input on the final equivalent transconductance in the related technology is greatly reduced, the accuracy of the transconductance is increased, and the problem of insufficient precision of the subthreshold input transconductance when a single-tube input is used in the simulation model is effectively avoided. The actual chip performance parameters can be better grasped in the design stage, reducing the uncertainty of the chip in the design stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a principle block diagram of the basic application scenario of the embodiment of the present application; Figure 2 It is a circuit schematic diagram of a single input tube in the related art; Figure 3 It is a circuit schematic diagram of a source negative feedback circuit with a single input tube plus a resistor in the related art; Figure 4 is a circuit schematic diagram of an input unit in an embodiment of the present application; Figure 4A is an overall circuit schematic diagram of an embodiment of the present application; Figure 5 It is a small signal circuit analysis circuit diagram of a source negative feedback circuit in the related art; Figure 6 It is a small signal circuit analysis circuit diagram of the circuit principle diagram in the embodiment of the present application. DETAILED DESCRIPTION

[0020] The technical solutions of the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, not all of them. Based on the implementation methods in the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the embodiments of the present application.

[0021] like Figure 1 Combined with Figure 2 and Figure 3As shown, in the basic application scenario of the embodiment of the present application, a power supply unit A, an input unit B and an amplifier circuit C are included. The input unit B includes a super source follower circuit and a source resistor, and the equivalent transconductance of the amplifier circuit can be determined by the source resistor. As the input pair of the amplifier circuit, the input unit B can determine the transconductance of the amplifier input by the resistance value of the source resistor. The simulation model of the resistor is generally more accurate, so when the resistance value is used to determine the input transconductance of the amplifier, the degree of control over the chip performance can be increased in the simulation stage, reducing the uncertainty in the design stage. As a further improvement, the input unit B is connected to a feedback unit (not shown in the figure) to improve the performance of the source follower, and the negative feedback mechanism is used to significantly reduce the output impedance, thereby improving the load capacity of the circuit, helping to improve the stability of the gain, and obtaining a more stable super source follower circuit.

[0022] The basic application scenario of the embodiment of the present application can be applied to almost all amplifier circuits. Taking the common-source and common-gate amplifier circuit as an example, Figure 3 When the circuit of the related technology shown is used as an input pair tube, when the resistance values ​​of the first source resistor Rs1 and the second source resistor Rs2 are appropriate, the resistance value can also be used to determine the final equivalent transconductance Gm, but the transconductance gm of the single input tube itself still has a large impact on the final equivalent transconductance, and still cannot meet people's requirements. This is because in the absence of additional negative feedback, the transconductance of the input tube has a large impact on the final equivalent value of the amplifier circuit. Equivalent transconductance is a parameter that describes the ability of a transistor to convert input voltage changes into output current changes. Ideally, it is hoped that the amplifier circuit can accurately amplify the voltage difference (differential mode signal) between the two signal input terminals while suppressing the common mode signal. Transconductance is a parameter that describes the amplification ability of a transistor or field effect tube. It is defined as the sensitivity of the transistor drain current to the gate voltage change, that is, the amount of change in the drain current for each unit voltage change in the gate voltage. In the related art, when a single input tube is used as input, its own transconductance will directly affect the gain and linearity of the amplifier circuit. For example, if the input signal causes the operating point of the input tube to change, the transconductance of the input tube will change accordingly, causing the gain of the amplifier circuit to change nonlinearly, thereby affecting the performance of the amplifier circuit.

[0023] It can be seen that the transconductance of a single input tube itself has a greater impact on the final equivalent transconductance, because the transconductance of a single input tube itself directly affects the responsiveness of the amplifier circuit to the input signal, and cannot meet people's requirements for the gain stability and accuracy of the amplifier circuit. The super source negative feedback circuit proposed in the embodiment of the present application, which uses resistance to determine the equivalent transconductance Gm, can further reduce the impact of the transconductance gm of the input tube on the overall equivalent input transconductance, and increase the accuracy of the equivalent transconductance Gm. The embodiment of the present application uses a super source follower circuit as the input end of the amplifier circuit, and a dual input tube, a dual feedback tube and a source resistor are provided in the super source follower circuit, which can effectively avoid the problems of gain nonlinearity and insufficient accuracy existing in the related art.

[0024] In the embodiment of the present application, the super source follower circuit can also be referred to as a super source negative feedback circuit (Super Source Follower, SSF for short), which plays a role in the overall circuit to provide an amplification effect of the amplifier circuit. The difference between the super source follower and the ordinary source follower is that the performance of the source follower of the related art is improved by introducing a negative feedback mechanism, achieving the effects of reducing output resistance, improving gain stability, enhancing DC stability, improving high-frequency response, and further realizing the function of determining equivalent transconductance by resistance. In the super source follower circuit of the embodiment of the present application, the first input tube and the second input tube of the input unit obtain the input signal, the first feedback tube and the second feedback tube provide feedback output to improve the performance of the source follower, and the negative feedback mechanism is used to significantly reduce the output impedance, thereby improving the load capacity of the circuit, helping to improve the stability of the gain, improve the linear performance of the circuit, and reduce the distortion of the output curve. The use of the super source follower circuit further reduces the influence of the transconductance of the first input tube and the second input tube itself on the overall equivalent transconductance of the amplifier circuit.

[0025] It is worth noting that in the implementation of the basic application scenario of the embodiment of the present application based on this basic application scenario, the circuit components involved in the circuit schematic diagram or principle block diagram are described as input tubes or feedback tubes, and the above-mentioned input tubes and feedback tubes can be transistors or MOS tubes. For example, the first input tube MP1 can be a MOS tube. The three ends of the first input tube MP1 in the figure are marked as 1, 2, and 3, respectively corresponding to the first end, the second end, and the third end of the first input tube MP1. In some embodiments, the first end of the first input tube MP1 is the gate of the MOS tube, the second end is the drain of the MOS tube, and the third end is the source of the MOS tube. The first feedback tube MN1 can also be a MOS tube, wherein the first end of the first feedback tube MN1 is the gate of the MOS tube, the second end is the drain of the MOS tube, and the third end is the source of the MOS tube. The second to sixth input tubes and the second to sixth feedback tubes are analogous, and different connection terminal numbers represent different pins of the MOS tube. In other embodiments, the first input tube MP1 may also be a transistor, and its corresponding three terminals are marked as 1, 2, and 3, respectively corresponding to the first terminal, the second terminal, and the third terminal of the first input tube MP1, wherein the first terminal is the base of the transistor, the second terminal is the emitter of the transistor, and the third terminal is the collector of the transistor. The first feedback tube MN1 may also be a transistor, wherein the first terminal of the first feedback tube MN1 is the base of the transistor, the second terminal is the emitter of the transistor, and the third terminal is the collector of the transistor, and the second to sixth input tubes and the second to sixth feedback tubes are analogous. MOS tubes and transistors (such as triodes) have many types and different connection methods. Those skilled in the art can, based on their ordinary technical knowledge in the field, set the input tubes and feedback tubes in the specification and drawings of this application to different MOS tubes or transistors, such as MOSFETs and bipolar transistors, according to the different requirements of different application scenarios without creative work, to achieve corresponding different functions. Exemplarily, in application scenarios requiring low power consumption design, MOSFET is selected to make full use of its high input impedance and low power consumption characteristics, and BJT is selected in application scenarios requiring high current drive to make full use of its higher current gain. Technical personnel in this field can also select MOS tubes and transistors at the same time according to the specific needs of the application scenario to combine the advantages of the two. For example, when a high-gain amplification is required, a transistor is selected as the input stage of the amplifier circuit to provide a larger current gain, and a MOS tube is used at the output stage of the amplifier circuit to provide low output impedance.

[0026] like Figure 4 and Figure 4A As shown, some specific implementations of the embodiments of the present application provide a circuit principle of a super source follower circuit, and simultaneously provide a super source follower device corresponding to the circuit principle diagram, in which a corresponding super source follower circuit is arranged. Figure 4The super source follower circuit in the embodiment includes two symmetrically arranged circuits, namely: a left half circuit including a first input tube and a first feedback tube, and a right half circuit including a second input tube and a second feedback tube, wherein: the source resistor includes a first source resistor R S1 and the second source resistor R S2 The first end of the first input tube MP1 is used to obtain the positive phase part Vin+ of the input signal Vin, and the first source resistor R S1 One end of the first source resistor R is connected between the second end of the first input tube MP1 and the third end of the first feedback tube MN1. S1 The other end is connected to the power supply unit A.

[0027] The first end of the second input tube MP2 is used to obtain the inverting part Vin- of the input signal Vin, the second end of the second input tube MP2 is connected to the third end of the second feedback tube MN2, the third end of the second input tube MP2 is connected to the first end of the second feedback tube MN2, and the second source resistor R S2 One end of the second source resistor R is connected between the second end of the second input tube MP2 and the third end of the second feedback tube MN2. S2 The other end is connected to the power supply unit A.

[0028] As a further improvement to the above technical solution, the third end of the first input tube MP1 is connected to the first end of the first feedback tube MN1, the second end of the first feedback tube MN1 is the first signal output end of the input unit B, and the third end of the first feedback tube MN1 is connected to the second end of the first input tube MP1.

[0029] The first end of the second feedback tube MN2 is connected to the third end of the second input tube MP2, the second end of the second feedback tube MN2 is the second signal output end of the input unit B, and the third end of the second feedback tube MN2 is connected to the first end of the second input tube.

[0030] In this embodiment, the first input tube MP1 and the second input tube MP2 are main input tubes, the feedback tubes include the first feedback tube MN1 and the second feedback tube MN2, and the source resistors include the first source resistor Rs1 and the second source resistor R S2 The compensation capacitor includes a first compensation capacitor C1 and a second compensation capacitor C2, and also includes: a total bias current IB, a bias current I of the first input tube MP1 B1 and the bias current I of the second input tube MP2 B2 The first input tube MP1 and the second input tube MP2 are responsible for converting the input voltage Vin into current. The first source resistor Rs1 and the second source resistor R S2The first compensation capacitor C1 and the second compensation circuit C2 provide loop compensation to improve loop stability. The first feedback tube MN1 and the second feedback tube MN2 are used to provide feedback to reduce the impact of the transconductance gm of the first input tube MP1 and the second input tube MP2 on the equivalent transconductance of the overall circuit. The bias current IB provides current for the first input tube MP1 and the first feedback tube MN1 branch. The bias current I B1 With the bias current I B2 The gate bias is provided for the first feedback tube MN1 and the second feedback tube MN2. The circuit structure provided in this embodiment can be used as an input terminal and is applicable to amplifiers of any structure, and has strong applicability and flexibility.

[0031] The above implementation method enables the super source follower circuit to accurately control the input transconductance Gm of the amplifier circuit by symmetrically setting the first source resistor and the second source resistor in the circuit, and achieves the purpose of setting the input transconductance Gm by adjusting the source resistance value, thereby increasing the degree of control over chip performance in the circuit simulation stage and reducing uncertainty in the circuit design stage. The first feedback tube and the second feedback tube provide a negative feedback path, which helps to stabilize the operating point of the amplifier circuit, reduce the influence of temperature and other external factors on the performance of the amplifier circuit, and improve the stability and reliability of the circuit.

[0032] The above implementation can respectively obtain the positive phase part and the negative phase part of the input signal, so that the super source circuit can process the differential signal, enhance the signal processing capability, and provide a circuit application method with high precision and high common mode rejection ratio based on the basic application scenario. It can also allow the use of different types of transistors or MOS tubes, adjust the circuit device selection and circuit structure according to the specific application scenario, improve the flexibility of circuit design, realize precise control of the amplifier input transconductance, improve the stability of the circuit and the signal processing capability, and reduce the uncertainty in the design process, thereby providing better performance in various analog circuit applications.

[0033] Preferably, the above-mentioned implementation of the embodiment of the present application also includes a first compensation capacitor C1 and a second compensation capacitor C2, one end of the first compensation capacitor C1 is connected between the third end of the first input tube MP1 and the first end of the first feedback tube MN1, and the other end is grounded, one end of the second compensation capacitor C2 is connected between the third end of the second input tube MP2 and the first end of the second feedback tube MN2, and the other end is grounded.

[0034] The above-mentioned implementation method optimizes the frequency response capability of the amplifier circuit by introducing a compensation capacitor, so that the amplifier circuit improves the performance when processing high-frequency signals. The first and second compensation capacitors can be used to adjust the phase margin and gain margin of the circuit, thereby improving the stability and gain flatness of the circuit when working at high frequencies, helping to reduce the distortion and phase shift of the circuit under high-frequency signals, offsetting the influence of parasitic capacitance and inductance in the high-frequency amplifier circuit on the stability of the circuit, improving the stability of the amplifier circuit, and providing a phase compensation function to ensure that the amplifier circuit has good phase characteristics within a wide frequency band, and realizes the continuity and stability of the output signal phase of the amplifier circuit at different frequencies, so that the super source follower circuit of the embodiment of the present application and the corresponding amplifier circuit can achieve better circuit performance in the application scenario of high-frequency signal processing. It can be seen that the embodiment of the present application sets a capacitor for loop compensation in the input unit, while realizing the input transconductance determined by the source resistance, and can also improve the loop stability by the compensation capacitor. Compared with a single tube and a single tube plus source negative feedback, the non-ideal factor term that is not related to the resistance value will be smaller, reducing the influence of the transconductance gm of the single tube itself on the equivalent transconductance Gm.

[0035] The embodiment of the present application also provides an amplifier circuit provided with a super source follower circuit. Taking a common-source common-gate amplifier circuit as an example, the amplifier circuit C selects a common-source common-gate amplifier circuit. The common-source common-gate amplifier circuit includes a third, fourth, fifth, and sixth input tubes, namely: a third input tube MP3, a fourth input tube MP4, a fifth input tube MP5, and a sixth input tube MP6, and a third, fourth, fifth, and sixth feedback tubes, namely: a third feedback tube MN3, a fourth feedback tube MN4, a fifth feedback tube MN5, and a sixth feedback tube MN6. The second end of the third input tube MP3 is connected to the second end of the fourth input tube MP4, the first end of the third input tube MP3 is connected to the first end of the fourth input tube MP4, and the power supply VDD is connected between the second end of the third input tube MP3 and the second end of the fourth input tube MP4.

[0036] The first end of the fifth input pipe MP5 is connected to the first end of the sixth input pipe MP6, the second end of the fifth input pipe MP5 is connected to the third end of the third input pipe MP3, the second end of the sixth input pipe MP6 is connected to the third end of the fourth input pipe MP4, the third end of the fifth input pipe MP5 is connected to the third end of the third feedback pipe MN3, and the third end of the sixth input pipe MP6 is connected to the third end of the fourth feedback pipe MN4; A first end of the third feedback tube MN3 is connected to a first end of the fourth feedback tube MN4, a second end of the third feedback tube MN3 is connected to a third end of the fifth feedback tube MN5, a second end of the fourth feedback tube MN4 is connected to a third end of the sixth feedback tube MN6, a first end of the fifth feedback tube MN5 is connected to a first end of the sixth feedback tube MN6, a second end of the fifth feedback tube MN5 is connected to a second end of the sixth feedback tube MN6 and then grounded.

[0037] The first signal output terminal Iout1 of the input unit A is connected between the second end of the third feedback tube MN3 and the third end of the fifth feedback tube MN5, and the second signal output terminal Iout2 of the input unit A is connected between the second end of the fourth feedback tube MN4 and the third end of the sixth feedback tube MN6.

[0038] In a specific implementation of the embodiment of the present application, VBP1 and VBP2 can be the body terminal or substrate terminal of the PMOS transistor, and VBN1 and VBN2 can be the body terminal or substrate terminal of the NMOS transistor, which are used to ensure that the body effect of the MOS tube is properly controlled to prevent the threshold voltage change caused by the body effect.

[0039] In this embodiment, the super source follower circuit reduces the output resistance by setting a feedback tube, so that the working point of the super source follower is stable, thereby improving the driving ability of the amplifier circuit, and its bias circuit can achieve good DC stability, thereby ensuring the stability and reliability of the output signal, helping to reduce the sensitivity of the amplifier circuit to changes in component parameters, thereby improving the overall stability of the circuit, significantly improving the performance of the circuit, reducing the output resistance and improving the gain stability of the amplifier circuit. It is worth noting that this embodiment is illustrated by taking the common source and common gate amplifier circuit as an example, but it does not mean that the amplifier circuit of the embodiment of the present application is limited to the common source and common gate amplifier circuit. The technology provided by the embodiment of the present application can be applied to any differential amplifier circuit, not limited to the amplifier circuit of the common source and common gate structure.

[0040] Small signal analysis: like Figure 5 and Figure 6As shown, by performing small signal circuit analysis and comparing the transconductance of the source negative feedback circuit in the related art with the transconductance of the super source follower circuit in the embodiment of the present application, it can be seen that the embodiment of the present application has a good technical effect in eliminating the influence of the input tube's own transconductance on the amplifier circuit. Small signal circuit analysis is one of the commonly used circuit analysis methods, which is suitable for analyzing and designing analog circuits. By approximating the nonlinear elements in the circuit (such as the input tube and the feedback tube) as linear elements, only the main linearization parameters of the device (such as transconductance, small signal resistance, small signal capacitance, etc.) are retained, avoiding complex nonlinear equations, and only using linear circuit theory to perform circuit analysis, simplifying the analysis process of complex circuits. Through small signal analysis, the frequency response of the circuit, the stability of the negative feedback system in the circuit, and other contents can be determined, and the gain, input and output impedance, frequency response and other characteristics of the circuit can be analyzed more simply without delving into the nonlinear characteristics of the circuit components.

[0041] The steps of performing small signal circuit analysis in the embodiment of the present application can be briefly described as follows: determine the static operating point, draw a DC equivalent circuit diagram, analyze the DC equivalent circuit diagram, calculate the DC voltage and current at each point in the circuit, replace the nonlinear elements in the circuit (such as input tubes and feedback tubes) with corresponding small signal equivalent models, and finally obtain the small signal circuit diagram corresponding to the super source follower circuit. Taking the half-circuit where the first input tube and the first feedback tube are located in the super source follower circuit as an example for small signal analysis, the small signal circuit can be obtained without considering the body effect: …… (1) …… (2) …… (3) Combining formulas (1), (2) and (3), we can obtain: …… (4) When a small signal analysis is performed on the single-tube input source negative feedback circuit of the related art, and the body effect is not considered, the small signal circuit of the single-tube source negative feedback is: …… (5) …… (6) …… (7) Combining formulas (1), (2) and (3), we can obtain: …… (8) contrast and It is known that when When larger, and Approximately equal to ,but The denominator of the non-ideal term is larger, making The approximation can be more accurate. According to the results of the above small signal analysis, the transconductance of the super source follower circuit of the embodiment of the present application has a higher accuracy than that of the related art.

[0042] Intuitive analysis: When the body effect and channel length modulation effect are not considered, Figure 3 The equivalent transconductance of the related art shown is: …… (9) and Figure 4 In the super source follower circuit of the embodiment of the present application shown, due to the existence of negative feedback, the loop is broken at the gate of the first feedback tube MN1, and the loop gain is: …… (10) Its equivalent input transconductance is: (11) In formula (11), when When larger, and Approximately equal to ,but The denominator of the non-ideal term is larger, making Through intuitive analysis, it can also be concluded that the super source follower circuit of the embodiment of the present application has smaller non-ideal factors that are independent of the resistance value than the single tube and single tube plus source negative feedback circuit of the related art, which reduces the influence of the transconductance gm of the single tube itself on the equivalent transconductance of the amplifier circuit and improves accuracy.

[0043] Those skilled in the art will appreciate that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of ordinary technicians in the field to which the embodiments of the present application belong. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined.

[0044] It should be noted that certain words are used in this specification and claims to refer to specific components. Those skilled in the art should understand that different manufacturers and producers may use different terms to refer to the same component. This specification and claims do not use the difference in terms as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction.

[0045] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the embodiments of the present application and form different embodiments. For example, any one of the embodiments claimed in the claims can be used in any combination in the embodiments of the present application.

[0047] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and set in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into multiple submodules or subunits or subcomponents. All features disclosed in this specification (including the corresponding claims, abstracts and drawings) and all processes or units of any method or device disclosed in this manner may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless otherwise expressly stated, each feature disclosed in this specification (including the corresponding claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the embodiments of the present application have been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A super source follower circuit, characterized in that: include: An input unit is configured to include at least a first input tube and a second input tube, wherein the first input tube has a first signal input end, and the second input tube has a second signal input end; A feedback unit is configured to include at least a first feedback tube and a second feedback tube, wherein the first feedback tube is connected to the first input tube and has a first signal output end, and the second feedback tube is connected to the second input tube and has a second signal output end; The power supply unit is connected to the input unit and the feedback unit through a source resistor, and is configured to provide power to the input unit and the feedback unit.

2. The super source follower circuit according to claim 1, characterized in that: The source resistor includes a first source resistor and a second source resistor, the first end of the first input tube is the first signal input end, the first signal input end is used to obtain the positive phase part of the input signal, one end of the first source resistor is connected between the second end of the first input tube and the third end of the first feedback tube, and the other end of the first source resistor is connected to the power supply unit; The first end of the second input tube is the second signal input end, and the second signal input end is used to obtain the inverted part of the input signal. The second end of the second input tube is connected to the third end of the second feedback tube, and the third end of the second input tube is connected to the first end of the second feedback tube. One end of the second source resistor is connected between the second end of the second input tube and the third end of the second feedback tube, and the other end of the second source resistor is connected to the power supply unit.

3. The super source follower circuit according to claim 2, characterized in that: The third end of the first input tube is connected to the first end of the first feedback tube, the second end of the first feedback tube is the first signal output end of the input unit, and the third end of the first feedback tube is connected to the second end of the first input tube.

4. The super source follower circuit according to claim 2, characterized in that: The first end of the second feedback tube is connected to the third end of the second input tube, the second end of the second feedback tube is the second signal output end, and the third end of the second feedback tube is connected to the first end of the second input tube.

5. The super source follower circuit according to claim 1, characterized in that: It also includes a first compensation capacitor and a second compensation capacitor, one end of the first compensation capacitor is connected between the third end of the first input tube and the first end of the first compensation tube, and the other end is grounded, one end of the second compensation capacitor is connected between the third end of the second input tube and the first end of the second feedback tube, and the other end is grounded.

6. A super source follower device, characterized in that: The super source follower device comprises the super source follower circuit according to any one of claims 1 to 5.

7. An amplifier circuit, characterized in that: The super source follower circuit comprises the super source follower circuit according to any one of claims 1 to 5, wherein the super source follower circuit is connected to the amplifier circuit.

8. The amplifier circuit according to claim 7, characterized in that: The amplifier circuit is a cascode amplifier circuit, which includes a third input tube, a fourth input tube, a fifth input tube, a sixth input tube, and a third feedback tube, a fourth feedback tube, a fifth feedback tube, and a sixth feedback tube. The second end of the third input tube is connected to the second end of the fourth input tube, the first end of the third input tube is connected to the first end of the fourth input tube, and the power supply is connected between the second end of the third input tube and the second end of the fourth input tube. The first end of the fifth input pipe is connected to the first end of the sixth input pipe, the second end of the fifth input pipe is connected to the third end of the third input pipe, the second end of the sixth input pipe is connected to the third end of the fourth input pipe, the third end of the fifth input pipe is connected to the third end of the third feedback pipe, and the third end of the sixth input pipe is connected to the third end of the fourth feedback pipe; The first end of the third feedback tube is connected to the first end of the fourth feedback tube, the second end of the third feedback tube is connected to the third end of the fifth feedback tube, the second end of the fourth feedback tube is connected to the third end of the sixth feedback tube, the first end of the fifth feedback tube is connected to the first end of the sixth feedback tube, and the second end of the fifth feedback tube is connected to the second end of the sixth feedback tube and then grounded.

9. The amplifier circuit according to claim 7, characterized in that: The first signal output end of the input unit is connected between the second end of the third feedback tube and the third end of the fifth feedback tube, and the second signal output end of the input unit is connected between the second end of the fourth feedback tube and the third end of the sixth feedback tube.

10. The amplifier circuit according to claim 8, characterized in that: The first input tube, the second input tube, the third input tube, the fourth input tube, the fifth input tube and the sixth input tube are transistors or MOS tubes, and the first feedback tube, the second feedback tube, the third feedback tube, the fourth feedback tube, the fifth feedback tube and the sixth feedback tube are transistors or MOS tubes.

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