Operational amplifier and electronic system

Abstract

The utility model provides an operational amplifier and an electronic system. The operational amplifier comprises an input protection matching module, an operational amplification module and a feedback module, the input protection matching module is used for receiving a differential input signal, clamping a voltage value of the differential input signal and carrying out impedance matching on two input ends of the operational amplification module; the operational amplification module is used for performing gain amplification on the differential input signal and outputting the signal; the feedback module is used for feeding back the output signal of the operational amplification module to the negative input end of the operational amplification module. The utility model is used for solving the problems that the operational amplifier is damaged due to the fact that the input voltage exceeds the active element voltage of the operational amplifier, the design of an additional analog anti-high-voltage circuit outside the operational amplifier is complex, and introduced impedance is not matched.

Description

Technical Field

[0001] The utility model relates to the field of analog circuits, in particular to an operational amplifier and an electronic system. Background Art

[0002] In motor application systems, it is indeed very important to use precision operational amplifiers (OPA) to monitor current. The operational amplifier can not only amplify weak signals, but also provide the necessary signal processing functions to ensure the accuracy and stability of the motor control system. However, improper operation may produce high analog input voltages, which will cause amplification errors in the operational amplifier circuit, impaired amplification performance, and even cause the precision operational amplifier to fail to work.

[0003] Based on this, in order to ensure the safety and reliability of precision operational amplifiers, it is necessary to ensure that the operational amplifiers can be used in high-voltage input environments. Generally speaking, operational amplifiers built on basic components such as field-effect transistors (MOSFETs) have certain operating voltage values. The typical operating voltage of MOSFETs is 3.3V, and the highest tolerable operating voltage does not exceed 10% of 3.3V, that is, 3.6V. This requires that the design of precision operational amplifiers has the ability to protect against high voltages, and that they cannot be broken down by analog voltages that exceed the power supply voltage limit. However, if an additional analog high-voltage protection circuit is added to the outside of the operational amplifier, this design is more complicated, and because the input impedance problem at both ends of the operational amplifier is often not taken into account, the gain error of the operational amplifier increases, reducing the amplification accuracy of the operational amplifier.

[0004] Based on this, how to achieve the situation where the input voltage exceeds the active component voltage of the operational amplifier, causing damage to the operational amplifier, and the design of the additional analog high-voltage protection circuit outside the operational amplifier is relatively complex and introduces impedance mismatch, which needs to be studied urgently.

[0005] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present application and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because they are described in the background technology section of the present application. Utility Model Content

[0006] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide an operational amplifier and an electronic system for solving the problems in the prior art that the input voltage exceeds the active component voltage of the operational amplifier, causing damage to the operational amplifier, and the external analog high-voltage protection circuit design of the operational amplifier is relatively complex and introduces impedance mismatch.

[0007] In order to achieve the above-mentioned purpose and other related purposes, the utility model provides an operational amplifier, comprising: an input protection matching module, an operational amplifier module and a feedback module;

[0008] The input protection matching module is arranged at the input end of the operational amplifier module, and is used to receive a differential input signal and clamp the voltage value of the differential input signal, and to perform impedance matching on two input ends of the operational amplifier module based on the impedance value of the feedback module;

[0009] The operational amplifier module is connected to the output end of the input protection matching module, and is used to perform gain amplification on the differential input signal and output the signal;

[0010] The feedback module is connected to the output end of the operational amplifier module and the negative input end of the operational amplifier module, and is used to feed back the output signal of the operational amplifier module to the negative input end of the operational amplifier module to increase the stability of the operational amplifier.

[0011] Optionally, the input protection matching module includes two clamping units, a first impedance adjustment unit and a second impedance adjustment unit; the two clamping units are respectively arranged at the two input ends of the operational amplifier module, for clamping the differential input signal; the first impedance adjustment unit and the second impedance adjustment unit are respectively arranged corresponding to each clamping unit; the first impedance adjustment unit is arranged between the corresponding clamping unit and the in-phase input end of the operational amplifier module; the second impedance adjustment unit is arranged between the corresponding clamping unit and the inverting input end of the operational amplifier module; the impedance value of the first impedance adjustment unit is equal to the sum of the impedance value of the second impedance adjustment unit and the impedance value of the feedback module.

[0012] Optionally, the clamping unit is configured as a natural field effect transistor; the gate of each natural field effect transistor is connected to a power supply voltage, the source receives the differential input signal, and the drain is connected to the input end of the corresponding operational amplifier module.

[0013] Optionally, the first impedance adjustment unit includes a first resistor and a second resistor; the first end of the first resistor is connected to the corresponding clamping unit, and the second end is connected to the in-phase input end of the operational amplifier module; the first end of the second resistor is connected to the common-mode input voltage, and the second end is connected to the second end of the first resistor.

[0014] Optionally, the second impedance adjustment unit includes a third resistor; a first end of the third resistor is connected to the corresponding clamping unit, and a second end is connected to the inverting input end of the operational amplifier module.

[0015] Optionally, the feedback module includes a fourth resistor; a first end of the fourth resistor is connected to the inverting input end of the operational amplifier module, and a second end of the fourth resistor is connected to the output end of the operational amplifier module.

[0016] Optionally, the operational amplifier module includes a differential-to-single-ended unit and a first-stage gain unit; the differential-to-single-ended unit is connected to the differential input signal and converts the differential input signal into a single-ended signal output; the first-stage gain unit is used to amplify the gain of the single-ended signal and output it to obtain a gain-amplified signal.

[0017] Optionally, the differential-to-single-ended unit includes a first PMOS tube, a second PMOS tube, a third PMOS tube, a first NMOS tube and a second NMOS tube; the gate of the first PMOS tube and the gate of the second PMOS tube respectively receive the differential input signal; the source of the first PMOS tube is connected to the source of the second PMOS tube and connected to the drain of the third PMOS tube; the source of the third PMOS tube is connected to the power supply voltage, and the gate is connected to the bias voltage; the drain of the first NMOS tube is connected to the drain of the first PMOS tube, the source is grounded, and the gate is connected to the source; the drain of the second NMOS tube is connected to the drain of the second PMOS tube and outputs the single-ended signal, the source is grounded, and the gate is connected to the gate of the first NMOS tube.

[0018] Optionally, the first-stage gain unit includes a fourth PMOS tube, a fifth PMOS tube, a third NMOS tube, a first capacitor and a second capacitor; the source of the fourth PMOS tube receives the single-ended signal, the gate is connected to the bias voltage, and the drain is connected to the first plate of the first capacitor; the gate of the third NMOS tube receives the single-ended signal, the source is grounded, and the drain is connected to the second plate of the first capacitor; the source of the fifth PMOS tube is connected to the power supply voltage, the gate is connected to the bias voltage, and the drain is connected to the second plate of the first capacitor; the first plate of the second capacitor is connected to the second plate of the first capacitor and outputs the gain amplified signal, and the second plate is grounded.

[0019] Optionally, the operational amplifier module further includes a second-stage gain unit; the second-stage gain unit receives the gain-amplified signal and is used to gain-amplify it again and output it without distortion.

[0020] To achieve the above object and other related objects, the utility model provides an electronic system including the above operational amplifier.

[0021] As described above, the operational amplifier and electronic system of the utility model have the following beneficial effects:

[0022] The operational amplifier and electronic system of the utility model not only clamp the voltage value of the differential input signal based on the input protection matching module, but also impedance match the two input ends of the operational amplifier module based on the impedance value of the feedback module, thereby further improving the performance and linearity of the operational amplifier, and effectively avoiding the input voltage exceeding the active component voltage of the operational amplifier, causing damage to the operational amplifier, and the problem that the design of the analog high-voltage protection circuit added outside the operational amplifier is relatively complicated and introduces impedance mismatch. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown is a schematic diagram of the framework of the operational amplifier of the present invention.

[0024] Figure 2 Shown is a structural schematic diagram of an operational amplifier of the utility model.

[0025] Figure 3 Shown is a structural schematic diagram of the operational amplifier module of the utility model.

[0026] Component number description

[0027] 1 Operational Amplifier

[0028] 11 Input protection matching module

[0029] 111 Clamp Unit

[0030] 112 first impedance adjustment unit

[0031] 113 Second impedance adjustment unit

[0032] 12 Operational amplifier module

[0033] 121 Differential to Single-Ended Unit

[0034] 122 First-stage gain unit

[0035] 123 Second stage gain unit

[0036] 124 Bias supply unit

[0037] 13 Feedback module DETAILED DESCRIPTION

[0038] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0039] See also Figure 1 to Figure 3 It should be noted that the illustrations provided in this embodiment are only used to schematically illustrate the basic concept of the utility model, and the drawings only show the components related to the utility model rather than the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0040] Example

[0041] like Figure 1 As shown, this embodiment provides an operational amplifier 1 , including: an input protection matching module 11 , an operational amplification module 12 and a feedback module 13 .

[0042] like Figure 1-2 As shown, the input protection matching module 11 is arranged at the input end of the operational amplifier module 12, for receiving a differential input signal and clamping the voltage value of the differential input signal, and performing impedance matching on the two input ends of the operational amplifier module 12 based on the impedance value of the feedback module 13.

[0043] Specifically, the input protection matching module 11 includes two clamping units 111 , a first impedance adjustment unit 112 and a second impedance adjustment unit 113 .

[0044] As an example, two clamping units 111 are respectively arranged at two input ends of the operational amplifier module 12, and are used to clamp the differential input signal (set as the first input signal INP and the second input signal INN in this embodiment); the first impedance adjustment unit 112 and the second impedance adjustment unit 113 are respectively arranged corresponding to each clamping unit 111; the first impedance adjustment unit 112 is arranged between the corresponding clamping unit 111 and the in-phase input end of the operational amplifier module 12; the second impedance adjustment unit 113 is arranged between the corresponding clamping unit 111 and the inverting input terminal of the operational amplifier module 12; the impedance value of the first impedance adjustment unit 112 is equal to the sum of the impedance value of the second impedance adjustment unit 112 and the impedance value of the feedback module 13 (in this embodiment, the sum of the impedance values ​​of the first resistor, the second resistor and the clamping unit 111 arranged at the in-phase input terminal is equal to the impedance value of the third resistor, the fourth resistor and the clamping unit 111 arranged at the negative phase input terminal) to achieve impedance matching of the two input terminals of the operational amplifier module 12, ensure the integrity of the signal of the operational amplifier, avoid signal distortion, and reduce noise.

[0045] In this embodiment, the clamping unit 111 is set as a natural field effect transistor; the gate of the natural field effect transistor is connected to the power supply voltage, the source receives the differential input signal (in this embodiment, the two natural field effect transistors are respectively connected to the first input signal INP and the second input signal INN), and the drain is connected to the corresponding input end of the operational amplifier module 12.

[0046] It should be noted that the natural field effect transistor is a semiconductor device that works on the principle of field effect, in which a naturally formed electric field, such as an electrostatic field or a photoelectric field, controls the conductivity of the transistor, and is usually used as a sensor switch device. In this embodiment, by setting the supply voltage as the gate voltage of the natural field effect transistor, when the source of the natural field effect transistor receives a higher differential input signal, since the gate-source voltage VGS is less than or equal to 0, the natural field effect transistor remains in a closed state, and the internal resistance is large, so that the differential input signal is reduced after passing through the internal resistance of the natural field effect transistor, thereby achieving the clamping of the differential input signal; conversely, when the natural field effect transistor receives a lower differential input signal, the differential input signal will not change the voltage amplitude output.

[0047] It should be further explained that, since the electric field of the natural field effect transistor is naturally formed, compared with other field effect transistors that need to rely on external power supply, it has a smaller layout area and can ensure more precise control of the input impedance of the operational amplifier 1.

[0048] In this embodiment, if Figure 2 As shown, the first impedance adjustment unit 111 includes a first resistor R1 and a second resistor R2; the first end of the first resistor R1 is connected to the corresponding clamping unit 111 (in this embodiment, it is set to be the clamping unit 111 connected to the first input signal INP), and the second end is connected to the in-phase input end of the operational amplifier module 12; the first end of the second resistor R2 is connected to the common-mode input voltage VCM, and the second end is connected to the second end of the first resistor R1.

[0049] In this embodiment, the second impedance adjustment unit 113 includes a third resistor R3; the first end of the third resistor R3 is connected to the corresponding clamping unit 111 (in this embodiment, it is set to be the clamping unit 111 connected to the second input signal INN), and the second end is connected to the inverting input end of the operational amplifier module 12.

[0050] like Figure 1-2 As shown, the operational amplifier module 12 is connected to the output end of the input protection matching module 11 (in this embodiment, connected to the two output ends of the input protection matching module), and is used to gain amplify and output the differential input signal.

[0051] Specifically, Figure 1 and Figure 3 As shown, the operational amplifier module 12 includes a differential-to-single-ended unit 121 and a first-stage gain unit 122 .

[0052] As an example, the differential-to-single-ended unit 121 is connected to the differential input signal and converts the differential input signal into a single-ended signal output; the first-stage gain unit 122 is used to amplify the gain of the single-ended signal and output a gain-amplified signal.

[0053] In this embodiment, if Figure 3 As shown, the differential-to-single-ended unit 121 includes a first PMOS tube MP1, a second PMOS tube MP2, a third PMOS tube MP3, a first NMOS tube MN1 and a second NMOS tube MN2; the gate of the first PMOS tube MP1 and the gate of the second PMOS tube MP2 respectively receive the differential input signal (in this embodiment, the first input signal INP and the second input signal INN); the source of the first PMOS tube MP1 is connected to the source of the second PMOS tube MP2 and is connected to the drain of the third PMOS tube MP3; the source of the third PMOS tube MP3 is connected to the power supply voltage VDD, and the gate is connected to the bias voltage; the drain of the first NMOS tube MN1 is connected to the drain of the first PMOS tube MP1, the source is grounded GND, and the gate is connected to the source; the drain of the second NMOS tube MN2 is connected to the drain of the second PMOS tube MP2 and outputs the single-ended signal, the source is grounded, and the gate is connected to the gate of the first NMOS tube MN1.

[0054] In this embodiment, the first-stage gain unit 122 includes a fourth PMOS transistor MP4, a third NMOS transistor MN, a fourth NMOS transistor MN, a first capacitor C1 and a second capacitor C2; the source of the third NMOS transistor MN3 receives the single-ended signal, the gate is connected to the bias voltage, and the drain is connected to the first plate of the first capacitor C1; the gate of the fourth NMOS transistor MN4 receives the single-ended signal, the source is grounded GND, and the drain is connected to the second plate of the first capacitor C1; the source of the fourth PMOS transistor MP4 is connected to the power supply voltage VDD, the gate is connected to the bias voltage, and the drain is connected to the second plate of the first capacitor C1; the first plate of the second capacitor C2 is connected to the second plate of the first capacitor C1 and outputs the gain amplified signal, and the second plate is grounded GND. Wherein, the first capacitor C1 performs corresponding phase compensation when the first-stage gain unit 122 amplifies the gain of the single-ended signal and outputs the gain amplified signal.

[0055] As an example, Figure 1As shown, the operational amplifier module 12 also includes a second-stage gain unit 123; the second-stage gain unit 123 receives the gain-amplified signal and is used to gain-amplify it again and output it without distortion. In this embodiment, the second-stage gain unit 123 is composed of a voltage follower to reduce the output resistance and improve the load capacity. In another embodiment, the second-stage gain unit 123 is composed of a complementary voltage follower.

[0056] In this embodiment, the operational amplifier module 12 further includes a bias power supply unit 124 to provide appropriate operating current for each stage. Figure 3 As shown, the bias power supply unit 124 includes: a fifth PMOS transistor MP5, a sixth PMOS transistor MP6, a fifth NMOS transistor MN5, a sixth NMOS transistor MN6, a seventh NMOS transistor MN7, an eighth NMOS transistor MN8 and a fifth resistor R5; wherein the source of the fifth PMOS transistor MP5 is connected to the power supply voltage VDD, and the gate is connected to the drain; the source of the sixth PMOS transistor MP6 is connected to the power supply voltage VDD, the gate is connected to the gate of the fifth PMOS transistor MP5 and is respectively connected to the third PMOS transistor MP3 and the fourth PMOS transistor MP4, and the drain is connected to The drain of the fifth NMOS tube NM5 is connected to the drain of the fifth PMOS tube MP5, the gate is connected to the gate of the sixth NMOS tube MN6, and the source is connected to the drain of the seventh NMOS tube MN7; the drain of the sixth NMOS tube MN is connected to the drain of the sixth PMOS tube, the gate is connected to the drain, and the source is connected to the drain of the eighth NMOS tube MN8; the source of the seventh NMOS tube is connected to the ground GND via the fifth resistor R5, and the gate is connected to the gate of the eighth NMOS tube MN8; the gate and drain of the eighth NMOS tube MN8 are connected, and the source is grounded.

[0057] It should be noted that the operational amplifier module 12 in this embodiment is a multi-stage direct-coupled amplifier circuit with high voltage gain, high input resistance and low output resistance. Its symmetric characteristics can improve the common-mode rejection ratio and other performances of the entire circuit. Its two input terminals constitute the inverting input terminal and the non-inverting input terminal of the entire circuit. However, its input not only needs to consider the problem of device performance reduction or even damage caused by excessive voltage, but also the problem of impedance matching. The input signal in this embodiment has the same path, and since the two natural field effect transistors are controlled by the same power supply voltage, the impedance matching is guaranteed to the greatest extent possible.

[0058] It should be further configured that the specific configuration of the operational amplifier module of this embodiment is not limited to this embodiment, and any configuration that can achieve gain amplification and output of the differential input signal based on the operational amplifier module 12 is within the protection scope of this embodiment.

[0059] like Figure 1As shown, the feedback module 13 is connected to the output end of the operational amplifier module 12 and the negative input end of the operational amplifier module 12, and is used to feed back the output signal of the operational amplifier module 12 to the negative input end of the operational amplifier module 12 to increase the stability of the operational amplifier 12.

[0060] Specifically, in this embodiment, the feedback module 13 includes a fourth resistor R4 ; a first end of the fourth resistor R4 is connected to the inverting input end of the operational amplifier module 12 , and a second end of the fourth resistor R4 is connected to the output end of the operational amplifier module 12 .

[0061] In this embodiment, the fourth resistor R4 is disposed between the second end of the third resistor R3 and the output end of the operational amplifier module 12 .

[0062] In this embodiment, the gain-bandwidth product of the circuit is reduced by setting the feedback module 13, thereby reducing the bandwidth of the amplifier, improving the stability of the circuit, and significantly reducing the output impedance of the operational amplifier, making it easier for the output end to drive the load. In addition, the feedback module 13 also increases the input impedance, which helps to reduce the load effect on the previous stage circuit. The feedback module 13 of this embodiment cooperates with the input protection matching module of the present application to increase the input impedance and match the two input ends, further improving the working performance of the operational amplifier.

[0063] This embodiment further provides an electronic system, comprising the operational amplifier 1 mentioned above.

[0064] As shown in Table 1 and Table 2 below, the operational amplifier of this embodiment can effectively prevent the input voltage from exceeding the power supply voltage and thus damaging the operational amplifier 1 and the electronic system. In Table 1, the power supply voltage in the operational amplifier module 12 is set to 3.3V.

[0065] Input voltage(V) Voltage after input protection matching module (V) 3 3 3.1 3.1 3.2 3.2 3.3 3.3 3.4 3.4 3.6 3.48 4 3.48 5 3.48 10 3.48

[0066] Table 1

[0067] At this time, input voltages higher than the power supply voltage of 3.3V are limited, and when exceeding 3.48V, they are limited to 3.48V, which is within the withstand voltage of the MOS tube of 3.6V (3.3V×110%).

[0068] In this table 2, the power supply voltage in the arithmetic amplifier module 12 is set to 3.6V.

[0069] Input voltage(V) Voltage after input protection matching module (V) 3 3 3.4 3.4 3.5 3.5 3.6 3.6 3.7 3.7 3.8 3.77 4 3.77 5 3.77 10 3.77

[0070] Table 2

[0071] At this time, input voltages higher than the power supply voltage of 3.6V are limited, and when exceeding 3.8V, they are limited to 3.77V, which is within the withstand voltage of the MOS tube of 3.96V (3.6V×110%).

[0072] In summary, the utility model provides an operational amplifier and an electronic system, including: an input protection matching module, an operational amplifier module and a feedback module; the input protection matching module is used to receive a differential input signal and clamp the voltage value of the differential input signal, and to impedance match the two input ends of the operational amplifier module; the operational amplifier module is used to gain amplify and output the differential input signal; the feedback module is used to feed back the output signal of the operational amplifier module to the negative input end of the operational amplifier module. The utility model is used to solve the problems that the input voltage exceeds the active component voltage of the operational amplifier, causing damage to the operational amplifier, and the external analog high-voltage protection circuit design of the operational amplifier is more complicated and introduces impedance mismatch. Therefore, the utility model effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0073] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed in the present invention shall still be covered by the claims of the present invention.

Claims

1. An operational amplifier, characterized in that: The operational amplifier at least includes: an input protection matching module, an operational amplification module and a feedback module; The input protection matching module is arranged at the input end of the operational amplifier module, and is used to receive a differential input signal and clamp the voltage value of the differential input signal, and to perform impedance matching on two input ends of the operational amplifier module based on the impedance value of the feedback module; The operational amplifier module is connected to the output end of the input protection matching module, and is used to perform gain amplification on the differential input signal and output the signal; The feedback module is connected to the output end of the operational amplifier module and the negative input end of the operational amplifier module, and is used to feed back the output signal of the operational amplifier module to the negative input end of the operational amplifier module to increase the stability of the operational amplifier.

2. The operational amplifier according to claim 1, wherein: The input protection matching module includes two clamping units, a first impedance adjustment unit and a second impedance adjustment unit; Two clamping units are respectively arranged at two input ends of the operational amplifier module, and are used to clamp the differential input signal; The first impedance adjustment unit and the second impedance adjustment unit are respectively arranged corresponding to each clamping unit; the first impedance adjustment unit is arranged between the corresponding clamping unit and the in-phase input terminal of the operational amplifier module; the second impedance adjustment unit is arranged between the corresponding clamping unit and the inverting input terminal of the operational amplifier module; the impedance value of the first impedance adjustment unit is equal to the sum of the impedance value of the second impedance adjustment unit and the impedance value of the feedback module.

3. The operational amplifier according to claim 2, wherein: The clamping unit is configured as a natural field effect transistor; the gate of each natural field effect transistor is connected to the power supply voltage, the source receives the differential input signal, and the drain is connected to the input end of the corresponding operational amplifier module.

4. The operational amplifier according to claim 2, wherein: The first impedance adjustment unit includes a first resistor and a second resistor; The first end of the first resistor is connected to the corresponding clamping unit, and the second end is connected to the in-phase input end of the operational amplifier module; the first end of the second resistor is connected to the common-mode input voltage, and the second end is connected to the second end of the first resistor.

5. The operational amplifier according to claim 2, wherein: The second impedance adjustment unit includes a third resistor; a first end of the third resistor is connected to the corresponding clamping unit, and a second end of the third resistor is connected to the inverting input end of the operational amplifier module.

6. The operational amplifier according to claim 1, wherein: The feedback module includes a fourth resistor; a first end of the fourth resistor is connected to the inverting input end of the operational amplifier module, and a second end of the fourth resistor is connected to the output end of the operational amplifier module.

7. The operational amplifier according to claim 1, wherein: The operational amplifier module includes a differential to single-ended unit and a first-stage gain unit; The differential-to-single-ended unit is connected to the differential input signal and converts the differential input signal into a single-ended signal output; The first-stage gain unit is used to amplify the gain of the single-ended signal and output it to obtain a gain-amplified signal.

8. The operational amplifier according to claim 7, characterized in that: The differential-to-single-ended unit includes a first PMOS tube, a second PMOS tube, a third PMOS tube, a first NMOS tube and a second NMOS tube; The gate of the first PMOS tube and the gate of the second PMOS tube receive the differential input signal respectively; the source of the first PMOS tube is connected to the source of the second PMOS tube and connected to the drain of the third PMOS tube; The source of the third PMOS tube is connected to the power supply voltage, and the gate is connected to the bias voltage; The drain of the first NMOS tube is connected to the drain of the first PMOS tube, the source is grounded, and the gate is connected to the source; The drain of the second NMOS tube is connected to the drain of the second PMOS tube and outputs the single-ended signal, the source is grounded, and the gate is connected to the gate of the first NMOS tube.

9. The operational amplifier according to claim 7, characterized in that: The first-stage gain unit includes a fourth PMOS transistor, a fifth PMOS transistor, a third NMOS transistor, a first capacitor and a second capacitor; The source of the fourth PMOS tube receives the single-ended signal, the gate is connected to the bias voltage, and the drain is connected to the first plate of the first capacitor; The gate of the third NMOS tube receives the single-ended signal, the source is grounded, and the drain is connected to the second plate of the first capacitor; The source of the fifth PMOS tube is connected to the power supply voltage, the gate is connected to the bias voltage, and the drain is connected to the second plate of the first capacitor; The first plate of the second capacitor is connected to the second plate of the first capacitor and outputs the gain amplified signal, and the second plate is grounded.

10. The operational amplifier according to claim 8 or 9, characterized in that: The operational amplifier module further includes a second-stage gain unit; the second-stage gain unit receives the gain-amplified signal and is used to gain-amplify the signal again and output it without distortion.

11. An electronic system, characterized in that: The electronic system comprises the operational amplifier according to any one of claims 1 to 10.

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