CN118760316A - A source follower - Google Patents

Abstract

Embodiments of the present disclosure provide a source follower. The source follower comprises a follower circuit and a negative feedback loop, when the source follower receives an input signal, the follower circuit can provide a first current for the output end of the source follower, the negative feedback loop can provide a second current for the output end of the source follower, the second current is gradually reduced in the transient response process until the second current is stabilized to be a preset current, when a large signal is input, the follower circuit and the negative feedback loop jointly provide a pull current, or when a large signal is output, the follower circuit and the negative feedback loop jointly provide a filling current, so that the carrying capacity of the source follower can be improved, and the quick transient response can be realized. In addition, the size of the current source and the input tube is not required to be increased, so that the power consumption and the cost of the circuit can be reduced.

Description

A source follower

Technical Field

Embodiments of the present disclosure relate to the technical field of integrated circuits, and in particular to a source follower.

Background Art

In an integrated circuit, a general source follower or super source follower circuit has a current source on one side of the current sourcing/sinking circuit, which has limited capability, while the other side has a stronger capability, resulting in an asymmetric output current sourcing/sinking capability. This results in a slower rising/falling edge speed of large signal input and output when the output node impedance is small.

In the prior art, a fast response of a large signal can be achieved by increasing the current source and the size of the input tube at the same time. However, adopting this prior art solution not only increases power consumption, but also increases circuit cost.

Summary of the invention

The embodiments described herein provide a source follower circuit that can achieve fast transient response and reduce circuit power consumption and cost.

The present disclosure provides a source follower, comprising: a follower circuit and a negative feedback loop.

The follower circuit is configured to provide a first current to the output terminal of the source follower when the source follower receives an input signal. The negative feedback loop is configured to provide a second current to the output terminal of the source follower when the source follower receives the input signal; wherein the second current gradually decreases during a transient response process until it stabilizes to a preset current.

In some embodiments of the present disclosure, the input end of the follower circuit is connected to the input end of the source follower, the output end of the follower circuit is connected to the output end of the negative feedback loop and the output end of the source follower, and the input end of the negative feedback loop is connected to the first reference node of the follower circuit.

The follower circuit is further configured to provide a first source current to the output terminal of the source follower when the source follower receives a first input signal. The negative feedback loop is configured to provide a second source current to the output terminal of the source follower when the source follower receives the first input signal.

In some embodiments of the present disclosure, the negative feedback loop includes: a current mirror module, a first transistor, a second transistor and a first current source.

The input end of the current mirror module and the first end of the second transistor are connected to the power supply voltage, the first output end of the current mirror module is connected to the input end of the first current source and the control end of the second transistor, the second output end of the current mirror module is connected to the second end of the first transistor, the output end of the first current source and the first end of the first transistor are grounded, and the second end of the second transistor is connected to the output end of the source follower.

In some embodiments of the present disclosure, the current mirror module includes: a third transistor and a fourth transistor.

The first end of the third transistor and the first end of the fourth transistor are connected to the power supply voltage, the control end of the third transistor, the second end of the third transistor and the control end of the fourth transistor are connected to the second end of the first transistor, and the second end of the fourth transistor is connected to the input end of the first current source and the control end of the second transistor.

In some embodiments of the present disclosure, the follower circuit includes: a fifth transistor, a sixth transistor, a second current source, and a third current source.

The input end of the second current source is connected to the power supply voltage, the output end of the second current source is connected to the first end of the fifth transistor, the second end of the sixth transistor and the output end of the source follower, the control end of the fifth transistor is connected to the input end of the source follower, the second end of the fifth transistor is connected to the control end of the sixth transistor, the control end of the first transistor and the input end of the third current source, and the output end of the third current source and the first end of the sixth transistor are grounded.

In some embodiments of the present disclosure, the input end of the follower circuit is connected to the input end of the source follower, the output end of the follower circuit is connected to the output end of the negative feedback loop and the output end of the source follower, and the input end of the negative feedback loop is connected to the second reference node of the follower circuit.

The follower circuit is further configured to provide a first sink current to the output terminal of the source follower when the source follower receives a second input signal. The negative feedback loop is configured to provide a second sink current to the output terminal of the source follower when the source follower receives the second input signal.

In some embodiments of the present disclosure, the negative feedback loop includes: a current mirror module, a first transistor, a second transistor and a first current source.

The first input end of the current mirror module is connected to the output end of the first current source and the control end of the second transistor, the second input end of the current mirror module is connected to the second end of the first transistor, the input end of the first current source and the first end of the first transistor are connected to the power supply voltage, the output end of the current mirror module and the first end of the second transistor are grounded, and the second end of the second transistor is connected to the output end of the source follower.

In some embodiments of the present disclosure, the current mirror module includes: a third transistor and a fourth transistor.

The first end of the third transistor and the first end of the fourth transistor are grounded, the control end of the third transistor, the second end of the third transistor and the control end of the fourth transistor are connected to the second end of the first transistor, and the second end of the fourth transistor is connected to the input end of the first current source and the control end of the second transistor.

In some embodiments of the present disclosure, the follower circuit includes: a fifth transistor, a sixth transistor, a second current source, and a third current source.

The input end of the second current source is connected to the first end of the fifth transistor, the second end of the sixth transistor and the output end of the source follower, the output end of the second current source is grounded, the control end of the fifth transistor is connected to the input end of the source follower, the second end of the fifth transistor is connected to the control end of the sixth transistor, the control end of the first transistor and the output end of the third current source, and the input end of the third current source and the first end of the sixth transistor are connected to the power supply voltage.

In some embodiments of the present disclosure, the aspect ratio of the third transistor: the aspect ratio of the fourth transistor = 1:1, and the aspect ratio of the sixth transistor: the aspect ratio of the first transistor = N:1, where N is a positive integer.

The preset current is Ib3-Ib2+N*Ib1, wherein Ib3 is the output current of the third current source, Ib2 is the output current of the second current source, and Ib1 is the output current of the first current source.

In the technical solution of the embodiment of the present disclosure, the source follower includes a follower circuit and a negative feedback loop. When the source follower receives an input signal, the follower circuit can provide a first current to the output end of the source follower, and the negative feedback loop can provide a second current to the output end of the source follower, and the second current gradually decreases during the transient response process until it stabilizes to a preset current. When there is a large signal input, the follower circuit and the negative feedback loop jointly provide a pull current, or when there is a large electrical signal output, the follower circuit and the negative feedback loop jointly provide a sink current, which can improve the load capacity of the source follower, so that a fast transient response can be achieved. In addition, there is no need to increase the size of the current source and the input tube, so the circuit power consumption and cost can be reduced.

The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

FIG1 is a schematic diagram of the structure of a source follower provided in an embodiment of the present disclosure.

FIG. 2 is a circuit diagram of a source follower provided in an embodiment of the present disclosure.

FIG. 3 is a circuit diagram of another source follower provided in an embodiment of the present disclosure.

DETAILED DESCRIPTION

In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work also fall within the scope of protection of the present disclosure.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person skilled in the art to which the subject matter of the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art, and will not be interpreted in an idealized or overly formal form unless otherwise explicitly defined herein. As used herein, a statement that two or more parts are "connected" or "coupled" together shall mean that the parts are joined together directly or through one or more intermediate components.

Reference to "embodiments" in this disclosure means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase "embodiments" in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this disclosure may be combined with other embodiments.

In addition, the terms "first", "second", etc. in the specification and claims of the present disclosure or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

In the description of the present disclosure, unless otherwise clearly stipulated and limited, the terms "connected" and "connected" should be understood in a broad sense. For example, the "connection" or "connection" of a circuit structure can refer to not only a physical connection, but also an electrical connection or a signal connection. For example, it can be a direct connection, that is, a physical connection, or it can be an indirect connection through at least one intermediate element, as long as the circuit is connected, and it can also be the internal connection of two elements; signal connection can refer to signal connection through a circuit as well as through a media medium, such as radio waves.

The term "and/or" in this disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and/or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character "/" in this article generally indicates that the associated objects before and after are in an "or" relationship.

In the description of the present disclosure, unless otherwise specified, "multiple" and "at least two" mean more than two (including two), and similarly, "multiple groups" and "at least two groups" mean more than two groups (including two).

In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

In a general source follower circuit or super source follower circuit, one side of the current sourcing/sinking is a current source with limited capability, while the other side has a stronger capability, resulting in an asymmetric output current sourcing/sinking capability. This results in a slow rising/falling edge speed of large signal input and output when the output node impedance is small, that is, a slow transient response of the circuit.

In order to solve the above problems, a current source can be added to the source follower circuit or super source follower circuit, and the size of the input tube can be increased. However, this solution causes higher circuit power consumption due to the addition of the current source, and increases the circuit cost due to the increase in the size of the input tube.

In view of this, the present disclosure provides a source follower, including a follower circuit and a negative feedback loop. When the source follower receives an input signal, the follower circuit can provide a first current to the output end of the source follower, and the negative feedback loop can provide a second current to the output end of the source follower, and the second current gradually decreases during the transient response process until it stabilizes to a preset current. When there is a large signal input, the follower circuit and the negative feedback loop jointly provide a sink current, or when there is a large electrical signal output, the follower circuit and the negative feedback loop jointly provide a pull current, which can improve the load capacity of the source follower, so that a fast transient response can be achieved. In addition, there is no need to increase the size of the current source and the input tube, so the circuit power consumption and cost can be reduced.

The technical solution of the present disclosure is described in detail below with reference to several specific embodiments.

FIG. 1 is a schematic diagram of the structure of a source follower provided by an embodiment of the present disclosure. As shown in FIG. 1 , the source follower 100 includes a follower circuit 110 and a negative feedback loop 120 .

Among them, the input end of the follower circuit 110 is connected to the input end IN of the source follower 100, the output end of the follower circuit 110 is connected to the output end of the negative feedback loop 120 and the output end OUT of the source follower 100, and the input end of the negative feedback loop 120 is connected to the reference node X of the follower circuit 110.

The follower circuit 110 is configured to provide a first current I1 to the output terminal OUT of the source follower 100 when the source follower 100 receives an input signal. The negative feedback loop 120 is configured to provide a second current I2 to the output terminal OUT of the source follower 100 when the source follower 100 receives an input signal, wherein the second current I2 gradually decreases during the transient response process until it stabilizes to a preset current Ipre.

Exemplarily, FIG2 is a circuit diagram of a source follower provided in an embodiment of the present disclosure. As shown in FIG2 , the negative feedback loop 120 includes a current mirror module 121 , a first transistor M1 , a second transistor M2 and a first current source IB1 .

The input end of the current mirror module 121 and the first end of the second transistor M2 are connected to the power supply voltage Vcc, the first output end of the current mirror module 121 is connected to the input end of the first current source IB1 and the control end of the second transistor M2, the second output end of the current mirror module 121 is connected to the second end of the first transistor M1, the output end of the first current source IB1 and the first end of the first transistor M1 are grounded, and the second end of the second transistor M2 is connected to the output end OUT of the source follower 100.

As shown in FIG2 , the current mirror module 121 may include a third transistor M3 and a fourth transistor M4. The first end of the third transistor M3 and the first end of the fourth transistor M4 are connected to the power supply voltage Vcc, the control end of the third transistor M3, the second end of the third transistor M3 and the control end of the fourth transistor M4 are connected to the second end of the first transistor M1, and the second end of the fourth transistor M4 is connected to the input end of the first current source IB1 and the control end of the second transistor M2.

The follower circuit 110 includes a fifth transistor M5, a sixth transistor M6, a second current source IB2 and a third current source IB3, the input end of the second current source IB2 is connected to the power supply voltage Vcc, the output end of the second current source IB2 is connected to the first end of the fifth transistor M5, the second end of the sixth transistor M6 and the output end OUT of the source follower 100, the control end of the fifth transistor M5 is connected to the input end IN of the source follower 100, the second end of the fifth transistor M5 is connected to the control end of the sixth transistor M6, the control end of the first transistor M1 and the input end of the third current source IB3, and the output end of the third current source IB3 and the first end of the sixth transistor M6 are grounded.

Specifically, the first transistor M1 and the sixth transistor M6 are N-type metal oxide semiconductor field effect transistors (MOS), and the second transistor M2, the third transistor M3, the fourth transistor M4 and the fifth transistor M5 are PMOS. The source of the second transistor M2, the source of the third transistor M3 and the source of the fourth transistor M4 are connected to the power supply voltage Vcc, the drain of the second transistor M2, the drain of the sixth transistor M6, the source of the fifth transistor M5 and the output end of the second current source IB2 are connected to the output end OUT of the source follower 100, and the gate of the second transistor M2 is connected to the drain of the fourth transistor M4 and the input end of the first current source IB1.

The source of the first transistor M1 and the source of the sixth transistor M6 are grounded, the drain of the first transistor M1 is connected to the drain of the third transistor M3, the gate of the third transistor M3 and the gate of the fourth transistor M4, the gate of the first transistor M1 is connected to the drain of the fifth transistor M5, the gate of the sixth transistor M6 and the input end of the third current source IB3, and the gate of the fifth transistor M5 is connected to the input end IN of the source follower 100. Among them, the connection point between the fifth transistor M5 and the third current source IB3 is the first reference node X1, then the input end of the negative feedback loop 120 is connected to the first reference node X1 of the follower circuit 110, and the connection point between the gate of the second transistor M2 and the drain of the fourth transistor M4 is the node Y.

The width-to-length ratio of the sixth transistor M6: the width-to-length ratio of the first transistor M1 = N: 1, where N is a positive integer, the current flowing through the first transistor M1 is 1/N of the current flowing through the sixth transistor M6, and the current flowing through the third transistor M3 is also 1/N of the current flowing through the sixth transistor M6. The width-to-length ratio of the third transistor M3: the width-to-length ratio of the fourth transistor M4 = 1: 1, so the pull-up current of the node Y is 1/N of the current flowing through the sixth transistor M6, and the pull-down current of the node Y is the output current of the first current source IB1 is Ib1.

When a positive step signal is input to the input terminal IN of the source follower 100, the impedance of the fifth transistor M5 increases, and the voltage of the first reference node X1 is pulled down to the ground by the third current source IB3, and the first transistor M1 and the sixth transistor M6 are turned off. The second current source IB2 provides the first source current I_source1 to the output terminal OUT of the source follower 100, that is, the first source current I_source1 is the output current Ib2 of the second current source IB2.

Inputting a positive step signal to the input terminal IN of the source follower 100 can indicate that the source follower 100 receives the first input signal, that is, the source follower 100 has a large signal input. At this time, the follower circuit 110 can provide the first source current I_source1 to the output terminal OUT of the source follower 100.

At this time, the current flowing through the sixth transistor M6 is zero, that is, the pull-up current of the node Y is zero, and the voltage of the node Y is pulled down to the ground by the pull-down current Ib1, and the second transistor M2 is turned on. Therefore, the second transistor M2 can provide the second pull current I_source2 to the output terminal OUT of the source follower 100, and the pull current I_source of the source follower 100 is I_source1+I_source2. Obviously, the pull current I_source of the source follower 100 becomes larger, and the balance between the pull current I_source and the sink current I_sink needs to be re-established.

When the source current I_source>sink current I_sink, the sixth transistor M6 is turned on, and current flows through the sixth transistor M6 to increase the sink current I_sink. At this time, the pull-up current of node Y increases, the voltage of node Y increases, and the current flowing through the second transistor M2 decreases, that is, the second source current I_source2 is reduced to reduce the source current I_source, thus completing a round of negative feedback. Through multiple rounds of negative feedback adjustment, the sink current I_sink can be made equal to the source current I_source, so that the source follower 100 reaches a steady state.

Therefore, the sink current I_sink in steady state is Ib3 + the current flowing through the sixth transistor M6, and the current flowing through the sixth transistor M6 = N * the current flowing through the first transistor M1 = N * Ib1, then in steady state it satisfies: Ib2 + I_source2 = N * Ib1 + Ib3, that is, I_source2 in steady state = N * Ib1 + Ib3 - Ib2.

In this way, when the source follower 100 receives the first input signal, that is, when the source follower 100 has a large signal input, the negative feedback loop 120 can provide a second source current I_source2 to the output terminal OUT of the source follower 100, and during the transient response process, the second source current I_source2 gradually decreases until it stabilizes to N*Ib1+Ib3-Ib2, that is, it stabilizes to the preset current Ipre.

In summary, when the source follower 100 receives the first input signal, the follower circuit 110 can provide the first pull current I_source1 to the output end of the source follower 100, and the negative feedback loop 120 can provide the second pull current I_source2 to the output end of the source follower 100, and the second pull current I_source2 gradually decreases during the transient response process until it stabilizes to the preset current Ipre. When there is a large signal input, the follower circuit 110 and the negative feedback loop 120 jointly provide the pull current I_source, which can improve the load capacity of the source follower 100, so that a fast transient response can be achieved. In addition, there is no need to increase the size of the current source and the input tube, so the circuit power consumption and cost can be reduced.

In some embodiments, FIG3 is a circuit diagram of another source follower provided in an embodiment of the present disclosure. As shown in FIG3 , the negative feedback loop 120 includes a current mirror module 121 , a first transistor M1 , a second transistor M2 and a first current source IB1 .

The first input end of the current mirror module 121 is connected to the output end of the first current source IB1 and the control end of the second transistor M2, the second input end of the current mirror module 121 is connected to the second end of the first transistor M1, the input end of the first current source IB1 and the first end of the first transistor M1 are connected to the power supply voltage Vcc, the output end of the current mirror module 121 and the first end of the second transistor M2 are grounded, and the second end of the second transistor M2 is connected to the output end OUT of the source follower 100.

As shown in Fig. 3, the current mirror module 121 may include a third transistor M3 and a fourth transistor M4. The first end of the third transistor M3 and the first end of the fourth transistor M4 are grounded, the control end of the third transistor M3, the second end of the third transistor M3 and the control end of the fourth transistor M4 are connected to the second end of the first transistor M1, and the second end of the fourth transistor M4 is connected to the input end of the first current source IB1 and the control end of the second transistor M2.

The follower circuit 110 includes a fifth transistor M5, a sixth transistor M6, a second current source IB2 and a third current source IB3, the input end of the second current source IB2 is connected to the first end of the fifth transistor M5, the second end of the sixth transistor M6 and the output end OUT of the source follower 100, the output end of the second current source IB2 is grounded, the control end of the fifth transistor M5 is connected to the input end IN of the source follower 100, the second end of the fifth transistor M5 is connected to the control end of the sixth transistor M6, the control end of the first transistor M1 and the output end of the third current source IB3, and the input end of the third current source IB3 and the first end of the sixth transistor M6 are connected to the power supply voltage Vcc.

Specifically, the first transistor M1 and the sixth transistor M6 are PMOS, and the second transistor M2, the third transistor M3, the fourth transistor M4 and the fifth transistor M5 are NMOS. The source of the second transistor M2, the source of the third transistor M3 and the source of the fourth transistor M4 are grounded, the drain of the second transistor M2, the drain of the sixth transistor M6, the source of the fifth transistor M5 and the input end of the second current source IB2 are connected to the output end OUT of the source follower 100, and the gate of the second transistor M2 is connected to the drain of the fourth transistor M4 and the output end of the first current source IB1.

The source of the first transistor M1 and the source of the sixth transistor M6 are connected to the power supply voltage Vcc, the drain of the first transistor M1 is connected to the drain of the third transistor M3, the gate of the third transistor M3 and the gate of the fourth transistor M4, the gate of the first transistor M1 is connected to the drain of the fifth transistor M5, the gate of the sixth transistor M6 and the output end of the third current source IB3, and the gate of the fifth transistor M5 is connected to the input end IN of the source follower 100. Among them, the connection point between the fifth transistor M5 and the third current source IB3 is the second reference node X2, then the input end of the negative feedback loop 120 is connected to the second reference node X2 of the follower circuit 110, and the connection point between the gate of the second transistor M2 and the drain of the fourth transistor M4 is the node Y.

The width-to-length ratio of the sixth transistor M6: the width-to-length ratio of the first transistor M1 = N: 1, where N is a positive integer, and the current flowing through the first transistor M1 is 1/N of the current flowing through the sixth transistor M6, and the current flowing through the third transistor M3 is also 1/N of the current flowing through the sixth transistor M6. The width-to-length ratio of the third transistor M3: the width-to-length ratio of the fourth transistor M4 = 1: 1, so the pull-down current of the node Y is 1/N of the current flowing through the sixth transistor M6, and the pull-up current of the node Y is the output current of the first current source IB1, which is Ib1.

When a reverse step signal is input to the input terminal IN of the source follower 100, the impedance of the fifth transistor M5 increases, and the voltage of the second reference node X2 is pulled up to the power supply voltage Vcc by the third current source IB3, and the first transistor M1 and the sixth transistor M6 are turned off. The second current source IB2 provides the first sink current I_sink1 to the output terminal OUT of the source follower 100, that is, the first sink current I_sink1 is the output current Ib2 of the second current source IB2.

Inputting a reverse step signal to the input terminal IN of the source follower 100 may indicate that the source follower 100 receives the second input signal, that is, the source follower 100 has a large signal output. At this time, the follower circuit 110 may provide a first sink current I_sink1 to the output terminal OUT of the source follower 100 .

At this time, the current flowing through the sixth transistor M6 is zero, that is, the pull-down current of the node Y is zero, and the voltage of the node Y is pulled up to the power supply voltage Vcc by the pull-up current Ib1, and the second transistor M2 is turned on. Therefore, the second transistor M2 can provide the second sink current I_sink2 to the output terminal OUT of the source follower 100, and the sink current I_sink of the source follower 100 is I_sink1+I_sink2. Obviously, the sink current I_sink of the source follower 100 becomes larger, and it is necessary to re-establish the balance between the sink current I_sink and the pull current I_source.

When the sink current I_sink>source current I_source, the sixth transistor M6 is turned on, and current flows through the sixth transistor M6 to increase the source current I_source. At this time, the pull-down current of node Y increases, the voltage of node Y decreases, and the current flowing through the second transistor M2 decreases, that is, the second sink current I_sink2 is reduced to reduce the sink current I_sink, thus completing a round of negative feedback. Through multiple rounds of negative feedback adjustment, the sink current I_sink=source current I_source, so that the source follower 100 reaches a steady state.

Therefore, the sink current and source current I_source in steady state is Ib3 + the current flowing through the sixth transistor M6, and the current flowing through the sixth transistor M6 = N * the current flowing through the first transistor M1 = N * Ib1, then in steady state it satisfies: Ib2 + I_sink2 = N * Ib1 + Ib3, that is, I_sink2 in steady state = N * Ib1 + Ib3 - Ib2.

In this way, when the source follower 100 receives the second input signal, that is, when the source follower 100 has a large signal output, the negative feedback loop 120 can provide a second sink current I_sink2 to the output terminal OUT of the source follower 100, and during the transient response process, the second source sink current I_sink2 gradually decreases until it stabilizes to N*Ib1+Ib3-Ib2, that is, it stabilizes to the preset current Ipre.

In summary, when the source follower 100 receives the second input signal, the follower circuit 110 can provide the first sink current I_sink1 to the output end of the source follower 100, and the negative feedback loop 120 can provide the second sink current I_sink2 to the output end of the source follower 100, and the second sink current I_sink2 gradually decreases during the transient response process until it stabilizes to the preset current Ipre. When there is a large signal output, the follower circuit 110 and the negative feedback loop 120 jointly provide the sink current, which can improve the load capacity of the source follower 100, so that a fast transient response can be achieved. In addition, there is no need to increase the size of the current source and the input tube, so the circuit power consumption and cost can be reduced.

An embodiment of the present disclosure further provides a buffer, comprising the source follower 100 provided in any of the above embodiments.

The buffer provided by the embodiment of the present disclosure includes the source follower 100 provided by any of the above embodiments, and has the same functional modules and beneficial effects as the source follower 100, which will not be repeated here.

The embodiments of the present disclosure further provide a voltage stabilizing chip, comprising the source follower 100 provided in any of the above embodiments.

The voltage stabilizing chip provided in the embodiments of the present disclosure includes the source follower 100 provided in any of the above embodiments, and has the same functional modules and beneficial effects as the source follower 100, which will not be described in detail here.

Unless the context clearly indicates otherwise, the singular form of the words used herein and in the appended claims includes the plural, and vice versa. Thus, when referring to the singular, the plural of the corresponding term is generally included. Similarly, the words "comprise" and "include" are to be interpreted as inclusive rather than exclusive. Likewise, the terms "include" and "or" should be interpreted as inclusive, unless such interpretation is expressly prohibited herein. Where the term "example" is used herein, particularly when it is located after a group of terms, the "example" is merely exemplary and illustrative and should not be considered exclusive or comprehensive.

Further aspects and scopes of adaptability become apparent from the description provided herein. It should be understood that various aspects of the present application can be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific embodiments herein are intended for purposes of illustration only and are not intended to limit the scope of the present application.

Several embodiments of the present disclosure are described in detail above, but it is obvious that those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. The protection scope of the present disclosure is defined by the attached claims.

Claims (10)

1.A source follower, comprising: a follower circuit and a negative feedback loop;

The follower circuit is configured to provide a first current to an output of the source follower when the source follower receives an input signal;

The negative feedback loop is configured to provide a second current to an output of the source follower when the source follower receives the input signal; the second current gradually decreases in the transient response process until the second current is stabilized to be a preset current.

2. The source follower of claim 1, wherein an input of the follower circuit is connected to an input of the source follower, an output of the follower circuit is connected to an output of the negative feedback loop and an output of the source follower, and an input of the negative feedback loop is connected to a first reference node of the follower circuit;

The follower circuit is further configured to provide a first pull current to an output of the source follower when the source follower receives a first input signal;

The negative feedback loop is configured to provide a second pull current to an output of the source follower when the source follower receives the first input signal.

3. The source follower of claim 2, wherein the negative feedback loop comprises: the circuit comprises a current mirror module, a first transistor, a second transistor and a first current source;

The input end of the current mirror module is connected with the first end of the second transistor, the first output end of the current mirror module is connected with the input end of the first current source and the control end of the second transistor, the second output end of the current mirror module is connected with the second end of the first transistor, the output end of the first current source and the first end of the first transistor are grounded, and the second end of the second transistor is connected with the output end of the source follower.

4. A source follower as defined in claim 3, wherein the current mirror module comprises: a third transistor and a fourth transistor;

The first end of the third transistor and the first end of the fourth transistor are connected with the power supply voltage, the control end of the third transistor, the second end of the third transistor and the control end of the fourth transistor are connected with the second end of the first transistor, and the second end of the fourth transistor is connected with the input end of the first current source and the control end of the second transistor.

5. The source follower of claim 4, wherein the follower circuit comprises: a fifth transistor, a sixth transistor, a second current source, and a third current source;

The input end of the second current source is connected with the power supply voltage, the output end of the second current source is connected with the first end of the fifth transistor, the second end of the sixth transistor and the output end of the source follower, the control end of the fifth transistor is connected with the input end of the source follower, the second end of the fifth transistor is connected with the control end of the sixth transistor, the control end of the first transistor and the input end of the third current source, and the output end of the third current source and the first end of the sixth transistor are grounded.

6. The source follower of claim 1, wherein an input of the follower circuit is connected to an input of the source follower, an output of the follower circuit is connected to an output of the negative feedback loop and an output of the source follower, and an input of the negative feedback loop is connected to a second reference node of the follower circuit;

the follower circuit is further configured to provide a first sink current to an output of the source follower when the source follower receives a second input signal;

the negative feedback loop is configured to provide a second sink current to an output of the source follower when the source follower receives the second input signal.

7. The source follower of claim 6, wherein the negative feedback loop comprises: the circuit comprises a current mirror module, a first transistor, a second transistor and a first current source;

The first input end of the current mirror module is connected with the output end of the first current source and the control end of the second transistor, the second input end of the current mirror module is connected with the second end of the first transistor, the input end of the first current source and the first end of the first transistor are connected with power supply voltage, the output end of the current mirror module and the first end of the second transistor are grounded, and the second end of the second transistor is connected with the output end of the source follower.

8. The source follower of claim 7, wherein the current mirror module comprises: a third transistor and a fourth transistor;

The first end of the third transistor and the first end of the fourth transistor are grounded, the control end of the third transistor, the second end of the third transistor and the control end of the fourth transistor are connected with the second end of the first transistor, and the second end of the fourth transistor is connected with the input end of the first current source and the control end of the second transistor.

9. The source follower of claim 8, wherein the follower circuit comprises: a fifth transistor, a sixth transistor, a second current source, and a third current source;

The input end of the second current source is connected with the first end of the fifth transistor, the second end of the sixth transistor and the output end of the source follower, the output end of the second current source is grounded, the control end of the fifth transistor is connected with the input end of the source follower, the second end of the fifth transistor is connected with the control end of the sixth transistor, the control end of the first transistor and the output end of the third current source, and the input end of the third current source and the first end of the sixth transistor are connected with the power supply voltage.

10. The source follower of claim 5 or 9, wherein the third transistor has an aspect ratio: the aspect ratio of the fourth transistor=1: 1, the aspect ratio of the sixth transistor: the aspect ratio of the first transistor = N:1, wherein N is a positive integer;

the preset current is Ib3-ib2+n×ib1, where Ib3 is the output current of the third current source, ib2 is the output current of the second current source, and Ib1 is the output current of the first current source.