Class-AB operational amplifier circuits and systems

Abstract

The present invention provides a Class-AB operational amplifier circuit and system, wherein a current adjustable module is used to receive a current adjustment instruction, and output an adjusted first voltage signal according to the current adjustment instruction; a current source module is used to generate a current signal; a voltage adjustment module is used to receive the first voltage signal and the current signal to generate an adjusted bias voltage signal; and a Class-AB output module is used to receive the adjusted bias voltage signal, and adjust the output current of the Class-AB operational amplifier according to the adjusted bias voltage signal. The circuit can output the adjusted first voltage signal according to the current adjustment instruction, thereby causing the voltage adjustment module to generate an adjusted bias voltage signal to adjust the output current of the Class-AB operational amplifier. The circuit can realize flexible regulation of the output current of the Class-AB operational amplifier, thereby meeting the requirements of different application scenarios.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a Class-AB operational amplifier circuit and system. Background Art

[0002] With the rapid development of integrated circuit technology, operational amplifiers, as the most important and basic devices of integrated circuits, are becoming increasingly important. In the current CMOS process, the size of transistors is constantly shrinking, and the power supply voltage is also decreasing, so the dynamic range of the operational amplifier will also decrease. Rail-to-rail operational amplifiers can make the input or output signal amplitude of the operational amplifier close to the positive and negative power supply voltage amplitudes, with high signal-to-noise ratio, output swing and dynamic range. However, the widely used rail-to-rail operational amplifier is a structure with a fixed output current signal, which is output by a ClassAB structure with a fixed bias voltage. Although this structure can output a large current and swing, the application scenario is single, and it cannot be flexibly adjusted for different application scenarios between low power consumption and high linearity. Summary of the invention

[0003] The object of the present invention is to provide a Class-AB operational amplifier circuit and system to flexibly regulate the output current of the Class-AB operational amplifier to meet the needs of different application scenarios.

[0004] The present invention provides a Class-AB operational amplifier circuit, which includes: a current adjustable module, which is used to receive a current adjustment instruction and output an adjusted first voltage signal according to the current adjustment instruction; a current source module, which is used to generate a current signal; a voltage adjustment module, which is used to receive the first voltage signal and the current signal and generate an adjusted bias voltage signal according to the first voltage signal and the current signal; and a Class-AB output module, which is used to receive the adjusted bias voltage signal and adjust the output current of the Class-AB operational amplifier according to the adjusted bias voltage signal.

[0005] Further, the current adjustable module includes: a first adjustable current branch and a second adjustable current branch; the first voltage signal includes: a first sub-voltage and a second sub-voltage; the first adjustable current branch includes: a first switch tube, having a gate, a source and a drain, the source is connected to the power supply voltage, and the gate is connected to the drain; a first adjustable current source, having a first end and a second end, the first end of the first adjustable current source is grounded; used to receive a current adjustment instruction and generate a first adjustable current according to the current adjustment instruction; a second switch tube, having a gate, a source and a drain, the source of the second switch tube is connected to the drain of the first switch tube, and the drain of the second switch tube is respectively connected to the gate of the second switch tube and the second end of the first adjustable current source, and is used to output a first sub-voltage through the gate of the second switch tube according to the first adjustable current;

[0006] The second adjustable current branch includes:

[0007] The second adjustable current source has a first end and a second end, the first end of the second adjustable current source is connected to the power supply voltage; it is used to receive a current adjustment instruction and generate a second adjustable current according to the current adjustment instruction; the third switch tube has a gate, a source and a drain, the drain of the third switch tube is respectively connected to the second end of the second adjustable current source and the gate of the third switch tube; it is used to output a second sub-voltage through the gate of the third switch tube according to the second adjustable current; the fourth switch tube has a gate, a source and a drain, the drain of the fourth switch tube is respectively connected to the source of the third switch tube and the gate of the fourth switch tube; the source of the fourth switch tube is grounded.

[0008] Furthermore, the current signal includes: a first sub-current and a second sub-current; the first sub-current is the same as the second sub-current; the current source module includes a first current source and a second current source; the first current source has a first end and a second end, the first end of the first current source is connected to the voltage adjustment module, and the second end of the first current source is grounded; used to generate a first sub-current; the second current source has a first end and a second end, the first end of the second current source is connected to the voltage adjustment module, and the second end of the second current source is grounded; used to generate a second sub-current.

[0009] Further, the voltage adjustment module includes: a fifth switch tube, having a gate, a source and a drain, the source of the fifth switch tube being connected to the power supply voltage; a sixth switch tube, having a gate, a source and a drain, the source of the sixth switch tube being connected to the power supply voltage, and the gate of the sixth switch tube being connected to the gate of the fifth switch tube; a seventh switch tube, having a gate, a source and a drain, the source of the seventh switch tube being respectively connected to the drain of the fifth switch tube and the first output end of the previous stage circuit; an eighth switch tube, having a gate, a source and a drain, the gate of the eighth switch tube being connected to the gate of the seventh switch tube, and the source of the eighth switch tube being respectively connected to the drain of the sixth switch tube and the second output end of the previous stage circuit; the first output end and the second output end are used to output the differential signal output by the previous stage circuit;

[0010] A ninth switch tube has a gate, a source and a drain, the source of the ninth switch tube is connected to the drain of the seventh switch tube, and the gate of the ninth switch tube is connected to the gate of the second switch tube; the drain of the ninth switch tube is connected to the first end of the first current source; a tenth switch tube has a gate, a source and a drain, the drain of the tenth switch tube is connected to the drain of the seventh switch tube, and the gate of the tenth switch tube is connected to the gate of the third switch tube; the source of the tenth switch tube is connected to the first end of the first current source; an eleventh switch tube has a gate, a source and a drain, the source of the eleventh switch tube is connected to the drain of the eighth switch tube, and the gate of the eleventh switch tube is connected to the gate of the second switch tube; the drain of the eleventh switch tube is connected to the first end of the second current source; a twelfth switch tube has a gate, a source and a drain, the drain of the twelfth switch tube is connected to the drain of the eighth switch tube, and the gate of the twelfth switch tube is connected to the gate of the third switch tube; the source of the twelfth switch tube is connected to the first end of the second current source.

[0011] Further, the Class-AB output module includes: a thirteenth switch tube, having a gate, a source and a drain, the source of the thirteenth switch tube is connected to the power supply voltage; the gate of the thirteenth switch tube is connected to the drain of the seventh switch tube; a fourteenth switch tube, having a gate, a source and a drain, the drain of the fourteenth switch tube is connected to the drain of the thirteenth switch tube and the third output end of the Class-AB output module, the gate of the fourteenth switch tube is connected to the first end of the first current source, and the source of the fourteenth switch tube is grounded; a fifteenth switch tube, having a gate, a source and a drain, the source of the fifteenth switch tube is connected to the power supply voltage; the gate of the fifteenth switch tube is connected to the drain of the eighth switch tube; a sixteenth switch tube, having a gate, a source and a drain, the drain of the sixteenth switch tube is respectively connected to the drain of the fifteenth switch tube and the fourth output end of the Class-AB output module, the gate of the sixteenth switch tube is connected to the first end of the second current source, and the source of the sixteenth switch tube is grounded.

[0012] Furthermore, the first adjustable current source includes: a first bias generating unit, having an input end, a first output end, a second output end and a ground end, the input end of the first bias generating unit is connected to an external SOURCE end, a first bias signal is output through the first output end of the first bias generating unit, and a second bias signal is output through the second output end of the first bias generating unit; the ground end is grounded; a first branch adjustable unit, having a first input end, a second input end, a switch control end and a ground end, the first input end of the first branch adjustable unit is connected to the first output end of the first bias generating unit, the second input end of the first branch adjustable unit is connected to the second output end of the first bias generating unit, and the switch control end of the first branch adjustable unit is used to receive a first switch instruction; the first branch adjustable unit is used to generate a first adjustable current according to the first switch instruction.

[0013] Furthermore, the first bias generating unit includes: a first resistor having a first end and a second end, the first end of the first resistor being connected to an external SOURCE end; a seventeenth switch tube having a gate, a source and a drain, the drain of the seventeenth switch tube being connected to the second end of the first resistor; the gate of the seventeenth switch tube being connected to the first output end of the first bias generating unit; an eighteenth switch tube having a gate, a source and a drain, the drain of the eighteenth switch tube being connected to the source of the seventeenth switch tube; the gate of the eighteenth switch tube being respectively connected to the drain of the seventeenth switch tube and the second output end of the first bias generating unit; the source of the eighteenth switch tube being grounded.

[0014] Further, the first branch adjustable unit includes: a first branch and at least one second branch; the first branch includes: a nineteenth switch tube, having a gate, a source and a drain, the drain of the nineteenth switch tube being connected to the drain of the second switch tube; the gate of the nineteenth switch tube being connected to the first output end of the first bias generating unit; a twentieth switch tube, having a gate, a source and a drain, the drain of the twentieth switch tube being connected to the source of the nineteenth switch tube; the gate of the twentieth switch tube being connected to the second output end of the first bias generating unit; the source of the twentieth switch tube being grounded;

[0015] Each second branch includes: a twenty-first switch tube, having a gate, a source and a drain, the drain of the twenty-first switch tube being connected to the drain of the second switch tube; the gate of the twenty-first switch tube being connected to the first output end of the first bias generating unit; a twenty-second switch tube, having a gate, a source and a drain, the drain of the twenty-second switch tube being connected to the source of the twenty-first switch tube; the gate of the twenty-second switch tube being connected to the second output end of the first bias generating unit through the first electronic switch; the gate of the twenty-second switch tube being grounded through the second electronic switch; and the source of the twenty-second switch tube being grounded.

[0016] Furthermore, the second adjustable current source includes: a second bias generating unit having a first output terminal, a second output terminal, a third output terminal and a power supply terminal, the first output terminal of the second bias generating unit being connected to an external S INK The first bias generating unit is connected to the first output terminal, the power supply terminal of the second bias generating unit is connected to the power supply voltage, the third bias signal is output through the second output terminal of the second bias generating unit, and the fourth bias signal is output through the third output terminal of the second bias generating unit;

[0017] The second branch adjustable unit includes a first input end, a second input end, a switch control end and a power supply end. The first input end of the second branch adjustable unit is connected to the second output end of the second bias generating unit. The second input end of the second branch adjustable unit is connected to the third output end of the second bias generating unit. The switch control end of the second branch adjustable unit is used to receive a second switch instruction. The second branch adjustable unit is used to generate a second adjustable current according to the second switch instruction.

[0018] Furthermore, the second bias generating unit includes: a second resistor having a first end and a second end, the first end of the second resistor being connected to an external SINK end; a twenty-third switch tube having a gate, a source and a drain, the drain of the twenty-third switch tube being connected to the second end of the second resistor; the gate of the twenty-third switch tube being connected to the third output end of the second bias generating unit; a twenty-fourth switch tube having a gate, a source and a drain, the drain of the twenty-fourth switch tube being connected to the source of the twenty-third switch tube; the gate of the twenty-fourth switch tube being connected to the drain of the twenty-third switch tube; and the source of the twenty-fourth switch tube being connected to the power supply voltage.

[0019] Further, the second branch adjustable unit includes: a third branch and at least one fourth branch; the third branch includes: a twenty-fifth switch tube, having a gate, a source and a drain, the drain of the twenty-fifth switch tube being connected to the drain of the third switch tube; the gate of the twenty-fifth switch tube being connected to the third output end of the second bias generating unit; a twenty-sixth switch tube, having a gate, a source and a drain, the drain of the twenty-sixth switch tube being connected to the source of the twenty-fifth switch tube; the gate of the twenty-sixth switch tube being connected to the second output end of the second bias generating unit; the source of the twenty-sixth switch tube being connected to the power supply voltage;

[0020] Each fourth branch includes: a twenty-seventh switch tube, having a gate, a source and a drain, the drain of the twenty-seventh switch tube is connected to the drain of the third switch tube; the gate of the twenty-seventh switch tube is connected to the third output end of the second bias generating unit; a twenty-eighth switch tube, having a gate, a source and a drain, the drain of the twenty-eighth switch tube is connected to the source of the twenty-seventh switch tube; the gate of the twenty-eighth switch tube is connected to the second output end of the second bias generating unit through the third electronic switch; the gate of the twenty-eighth switch tube is connected to the power supply voltage through the fourth electronic switch; and the source of the twenty-eighth switch tube is connected to the power supply voltage.

[0021] The present invention provides a Class-AB operational amplifier system, characterized by comprising any one of the above-mentioned Class-AB operational amplifier circuits.

[0022] The Class-AB operational amplifier circuit and system provided by the present invention include: a current adjustable module for receiving a current adjustment instruction and outputting an adjusted first voltage signal according to the current adjustment instruction; a current source module for generating a current signal; a voltage adjustment module for receiving a first voltage signal and a current signal and generating an adjusted bias voltage signal according to the first voltage signal and the current signal; and a Class-AB output module for receiving an adjusted bias voltage signal and adjusting the output current of the Class-AB operational amplifier according to the adjusted bias voltage signal. The circuit can output an adjusted first voltage signal according to the current adjustment instruction, thereby causing the voltage adjustment module to generate an adjusted bias voltage signal to adjust the output current of the Class-AB operational amplifier. The circuit can realize flexible regulation of the output current of the Class-AB operational amplifier, thereby meeting the requirements of different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific implementation methods of the present invention 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 present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic diagram of a Class-AB operational amplifier circuit provided by an embodiment of the present invention;

[0025] Figure 2 A schematic diagram of a Class-AB operational amplifier circuit provided by an embodiment of the present invention;

[0026] Figure 3 A circuit diagram of a first adjustable current source provided by an embodiment of the present invention;

[0027] Figure 4 A circuit diagram of a first adjustable current source provided by an embodiment of the present invention;

[0028] Figure 5 A circuit diagram of a second adjustable current source provided by an embodiment of the present invention;

[0029] Figure 6 A circuit diagram of a second adjustable current source provided by an embodiment of the present invention.

[0030] Icons: 10-current adjustable module; 11-current source module; 12-voltage adjustment module; 13-Class-AB output module; M1-first switch tube; M2-second switch tube; M3-third switch tube; M4-fourth switch tube; M9-fifth switch tube; M10-sixth switch tube; M11-seventh switch tube; M12-eighth switch tube; M13-ninth switch tube; M14-tenth switch tube; M15-eleventh switch tube; M16-twelfth switch tube; M5-thirteenth switch tube; M6-fourteenth switch tube; M7-fifteenth switch tube; M8-sixteenth switch tube; M17-seventeenth switch tube; M18-eighteenth switch tube; M19-the nineteenth switch tube; M20-the twentieth switch tube; M21-the twenty-first switch tube; M22-the twenty-second switch tube; M23-the twenty-third switch tube; M24-the twenty-fourth switch tube; M25-the twenty-fifth switch tube; M26-the twenty-sixth switch tube; M27-the twenty-seventh switch tube; M28-the twenty-eighth switch tube; IB1-the first adjustable current source; IB2-the second adjustable current source; IB3-the first current source; IB4-the second current source; VBP-the first sub-voltage; VBN-the second sub-voltage; S1, S2, S3, S4, S5, S6, S7, S8-electronic switches; R1-the first resistor; R2-the second resistor. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The widely used rail-to-rail operational amplifier is a structure with a fixed output current signal, which is output by a Class AB structure with a fixed bias voltage. This structure has the following disadvantages: (1) Affected by PVT (Process, Voltage and Temperature) fluctuations, the bias voltage will be affected by PVT fluctuations. Under certain process angles and power supply voltage fluctuations, the output current will be unstable, affecting the linearity and stability of the circuit; (2) Affected by the load, when adapting to circuits with different loads, this structure has poor matching and its own DC (Direct Current) operating point is affected; (3) The usage scenario is single, and it cannot be flexibly adjusted for different application scenarios between low power consumption and high linearity. Based on this, an embodiment of the present invention provides a Class-AB operational amplifier circuit and system, which can be applied to applications where the output current of a Class-AB operational amplifier needs to be adjustable, and is particularly suitable for use scenarios where an op amp needs to have a large output swing and good linearity.

[0033] To facilitate understanding of this embodiment, a Class-AB operational amplifier circuit disclosed in an embodiment of the present invention is first introduced. Figure 1 As shown, the circuit includes: a current adjustable module 10, a current source module 11, a voltage adjustment module 12 and a Class-AB output module 13.

[0034] The current adjustable module 10 is used to receive a current adjustment instruction and output an adjusted first voltage signal according to the current adjustment instruction; the current source module 11 is used to generate a current signal; the voltage adjustment module 12 is used to receive the first voltage signal and the current signal and generate an adjusted bias voltage signal according to the first voltage signal and the current signal; the Class-AB output module 13 is used to receive the adjusted bias voltage signal and adjust the output current of the Class-AB operational amplifier according to the adjusted bias voltage signal.

[0035] The above-mentioned current adjustment instruction can be issued by an external circuit, and the current in the current adjustable module can be adjusted by the current adjustment instruction. For example, the current adjustable module may include an adjustable current source, and the current provided by the adjustable current source can be adjusted according to the current adjustment instruction. The current adjustable module can output an adjusted first voltage signal according to the adjusted current; the above-mentioned current source module is usually composed of a current source, and a corresponding current signal can be generated by the current source. The above-mentioned voltage adjustment module can generate a bias voltage signal according to the first voltage signal and the current signal, and the bias voltage signal can provide a bias voltage for the switch tube in the Class-AB output module. Since the first voltage signal can be adjusted according to the current adjustment instruction, the bias voltage signal generated in the voltage adjustment module can be adjusted, thereby adjusting the output current of the Class-AB operational amplifier.

[0036] The above-mentioned Class-AB operational amplifier circuit can output an adjusted first voltage signal according to the current adjustment instruction, thereby enabling the voltage adjustment module to generate an adjusted bias voltage signal to adjust the output current of the Class-AB operational amplifier. The circuit can realize flexible regulation of the output current of the Class-AB operational amplifier, thereby meeting the requirements of different application scenarios.

[0037] Furthermore, the current adjustable module 10 includes: a first adjustable current branch and a second adjustable current branch; the first voltage signal includes: a first sub-voltage VBP and a second sub-voltage VBN;

[0038] The first adjustable current branch includes:

[0039] The first switch tube M1 has a gate, a source and a drain, the source is connected to the power supply voltage VDD, and the gate is connected to the drain;

[0040] A first adjustable current source IB1 has a first end and a second end, and the first end of the first adjustable current source IB1 is grounded; and is used to receive a current adjustment instruction and generate a first adjustable current according to the current adjustment instruction;

[0041] The second switch tube M2 has a gate, a source and a drain, the source of the second switch tube M2 is connected to the drain of the first switch tube M1, and the drain of the second switch tube M2 is respectively connected to the gate of the second switch tube M2 and the second end of the first adjustable current source IB1, and is used to output the first sub-voltage VBP through the gate of the second switch tube M2 according to the first adjustable current;

[0042] The first switch tube M1 and the second switch tube M2 can be implemented by MOS tubes, and the first adjustable current source IB1 is a current source that can change the current size; Figure 2A schematic diagram of a Class-AB operational amplifier circuit is shown, in which a first switch tube M1, a second switch tube M2 and a first adjustable current source are connected in series in sequence, the first switch tube M1 and the second switch tube M2 are diode-connected, and a first sub-voltage VBP is derived from the gate of the second switch tube M2.

[0043] The second adjustable current branch includes:

[0044] The second adjustable current source IB2 has a first end and a second end, the first end of the second adjustable current source IB2 is connected to the power supply voltage VDD; it is used to receive a current adjustment instruction and generate a second adjustable current according to the current adjustment instruction;

[0045] The third switch tube M3 has a gate, a source and a drain, and the drain of the third switch tube M3 is respectively connected to the second end of the second adjustable current source IB2 and the gate of the third switch tube M3; and is used to output the second sub-voltage VBN through the gate of the third switch tube M3 according to the second adjustable current;

[0046] The fourth switch tube M4 has a gate, a source and a drain. The drain of the fourth switch tube M4 is respectively connected to the source of the third switch tube M3 and the gate of the fourth switch tube M4. The source of the fourth switch tube M4 is grounded.

[0047] The third switch tube M3 and the fourth switch tube M4 can be implemented by MOS tubes, and the second adjustable current source IB2 is a current source that can change the current size; Figure 2 As shown, the second adjustable current source IB2, the third switch tube M3 and the fourth switch tube M4 are connected in series in sequence, the third switch tube M3 and the fourth switch tube M4 are diode-connected, and the second sub-voltage VBN is output from the gate of the third switch tube M3.

[0048] Further, the current signal includes: a first sub-current and a second sub-current; the first sub-current is the same as the second sub-current; the current source module 11 includes a first current source IB3 and a second current source IB4;

[0049] A first current source IB3 has a first end and a second end, the first end of the first current source is connected to the voltage adjustment module, and the second end of the first current source is grounded; and is used to generate a first sub-current;

[0050] The second current source IB4 has a first end and a second end, the first end of the second current source is connected to the voltage adjustment module, and the second end of the second current source IB4 is grounded; and is used to generate a second sub-current.

[0051] like Figure 2As shown, in this embodiment, the Class-AB operational amplifier circuit adopts a fully differential structure. Therefore, the first sub-current generated by the first current source IB3 is the same as the second sub-current generated by the second current source IB4. The first sub-current and the second sub-current can also be determined according to the first adjustable current generated by the first adjustable current source IB1. For example, it can be m times the first adjustable current, etc.

[0052] Furthermore, the voltage adjustment module 12 includes:

[0053] A fifth switch tube M9 has a gate, a source and a drain, and the source of the fifth switch tube M9 is connected to a power supply voltage VDD;

[0054] The sixth switch tube M10 has a gate, a source and a drain, the source of the sixth switch tube M10 is connected to the power supply voltage VDD, and the gate of the sixth switch tube M10 is connected to the gate of the fifth switch tube M9;

[0055] The seventh switch tube M11 has a gate, a source and a drain, and the source of the seventh switch tube M11 is respectively connected to the drain of the fifth switch tube M9 and the first output end of the previous stage circuit;

[0056] an eighth switch tube M12 having a gate, a source and a drain, wherein the gate of the eighth switch tube M12 is connected to the gate of the seventh switch tube M11, and the source of the eighth switch tube M12 is respectively connected to the drain of the sixth switch tube M10 and the second output end of the previous stage circuit; the first output end and the second output end are used to output the differential signals Iin+ and Iin- output by the previous stage circuit;

[0057] like Figure 2 As shown, the fifth switch tube M9, the sixth switch tube M10, the seventh switch tube M11 and the eighth switch tube M12 can be implemented by MOS tubes, and these four switch tubes are current source loads of cascode structure. This current source load of cascode structure can be used to enhance the performance and stability of the amplifier. The gate bias voltage of the fifth switch tube M9 and the sixth switch tube M10 is vb1, and the gate bias voltage of the seventh switch tube M11 and the eighth switch tube M12 is vb2. vb1 and vb2 can be provided by an external circuit; the previous stage circuit (not shown in the figure) can output differential signals Iin+ and Iin- through the first output terminal and the second output terminal of the previous stage circuit, wherein Iin+ is input to the current source load of the cascode structure through the common node of the fifth switch tube M9 and the seventh switch tube M11, and Iin- is input to the current source load of the cascode structure through the common node of the sixth switch tube M10 and the eighth switch tube M12.

[0058] The ninth switch tube M13 has a gate, a source and a drain. The source of the ninth switch tube M13 is connected to the drain of the seventh switch tube M11, and the gate of the ninth switch tube M13 is connected to the gate of the second switch tube M2. The drain of the ninth switch tube M13 is connected to the first end of the first current source IB3.

[0059] The tenth switch tube M14 has a gate, a source and a drain. The drain of the tenth switch tube M14 is connected to the drain of the seventh switch tube M11, and the gate of the tenth switch tube M14 is connected to the gate of the third switch tube M3; the source of the tenth switch tube M14 is connected to the first end of the first current source IB3;

[0060] The eleventh switch tube M15 has a gate, a source and a drain. The source of the eleventh switch tube M15 is connected to the drain of the eighth switch tube M12. The gate of the eleventh switch tube M15 is connected to the gate of the second switch tube M2. The drain of the eleventh switch tube M15 is connected to the first end of the second current source IB4.

[0061] The twelfth switch tube M16 has a gate, a source and a drain. The drain of the twelfth switch tube M16 is connected to the drain of the eighth switch tube M12, and the gate of the twelfth switch tube M16 is connected to the gate of the third switch tube M3; the source of the twelfth switch tube M16 is connected to the first end of the second current source IB4.

[0062] The ninth switch tube M13 and the tenth switch tube M14 form a floating current source, and the eleventh switch tube M15 and the twelfth switch tube M16 form a floating current source; Figure 2 As shown, the first switch tube M1 and the second switch tube M2 are connected by diodes, and the branch current thereof is the first adjustable current generated by the first adjustable current source IB1. The gate of the second switch tube M2 is connected to the gates of the ninth switch tube M13 and the eleventh switch tube M15, that is, the first switch tube M1 and the second switch tube M2 connected by diodes generate a first sub-voltage VBP to bias the ninth switch tube M13 and the eleventh switch tube M15; the ninth switch tube M13 and the tenth switch tube M14 are PMOS and NMOS respectively, and the sum of the currents flowing through the two is the first sub-current generated by the first current source IB3;

[0063] The third switch tube M3 and the fourth switch tube M4 are diode-connected, and the branch current thereof is the second adjustable current generated by the second adjustable current source IB2. The gate of the third switch tube M3 is connected to the gates of the tenth switch tube M14 and the twelfth switch tube M16, that is, the third switch tube M3 and the fourth switch tube M4 connected by diodes generate a second self-voltage VBN to bias the tenth switch tube M14 and the twelfth switch tube M16. The eleventh switch tube M15 and the twelfth switch tube M16 are PMOS and NMOS respectively, and the sum of the currents flowing through the two is the second sub-current generated by the second current source IB4.

[0064] Furthermore, the Class-AB output module 13 includes:

[0065] The thirteenth switch tube M5 has a gate, a source and a drain, and the source of the thirteenth switch tube M5 is connected to the power supply voltage VDD; the gate of the thirteenth switch tube M5 is connected to the drain of the seventh switch tube M11;

[0066] A fourteenth switch tube M6 has a gate, a source and a drain, the drain of the fourteenth switch tube M6 is connected to the drain of the thirteenth switch tube M5 and the third output terminal of the Class-AB output module, the gate of the fourteenth switch tube M6 is connected to the first terminal of the first current source IB3, and the source of the fourteenth switch tube M6 is grounded;

[0067] The fifteenth switch tube M7 has a gate, a source and a drain, and the source of the fifteenth switch tube M7 is connected to the power supply voltage; the gate of the fifteenth switch tube M7 is connected to the drain of the eighth switch tube M12;

[0068] The sixteenth switch tube M8 has a gate, a source and a drain. The drain of the sixteenth switch tube M8 is respectively connected to the drain of the fifteenth switch tube M7 and the fourth output end of the Class-AB output module. The gate of the sixteenth switch tube M8 is connected to the first end of the second current source IB4. The source of the sixteenth switch tube M8 is grounded.

[0069] like Figure 2 As shown, the thirteenth switch tube M5, the fourteenth switch tube M6, the fifteenth switch tube M7 and the sixteenth switch tube M8 can be implemented by MOS tubes, and these four switch tubes constitute the output stage of the Class-AB operational amplifier; the two ends of the floating current source composed of the ninth switch tube M13 and the tenth switch tube M14 are represented by nodes A and B respectively, wherein node A is connected to the gate of the thirteenth switch tube M5 in the Class-AB output module, and node B is connected to the gate of the fourteenth switch tube M6 in the Class-AB output module.

[0070] The two ends of the floating current source formed by the eleventh switch tube M15 and the twelfth switch tube M16 are represented by nodes C and D respectively, wherein the node C is connected to the gate of the fifteenth switch tube M7 in the Class-AB output module, and the node D is connected to the gate of the sixteenth switch tube M8 in the Class-AB output module; thereby, the magnitude of the output stage current of the Class-AB operational amplifier can be affected.

[0071] If the current flowing through the ninth switch tube M13 decreases (the first sub-voltage VBP remains unchanged), the current flowing through the tenth switch tube M14 increases (the second sub-voltage VBN remains unchanged), so the VGS13 corresponding to the ninth switch tube M13 decreases, and the VGS14 corresponding to the tenth switch tube M14 increases, so that the gate voltage of the thirteenth switch tube M5 decreases, and the gate voltage of the fourteenth switch tube M6 also decreases, thereby realizing the push-pull output of the signal rail-to-rail.

[0072] If the current flowing through the eleventh switch tube M15 decreases (the first sub-voltage VBP remains unchanged), the current flowing through the twelfth switch tube M16 increases (the second sub-voltage VBN remains unchanged), so the VGS15 corresponding to the eleventh switch tube M15 decreases, and the VGS16 corresponding to the twelfth switch tube M16 increases, so that the gate voltage of the fifteenth switch tube M7 decreases, and the gate voltage of the sixteenth switch tube M8 also decreases, thereby realizing the push-pull output of the signal rail-to-rail.

[0073] Further, the first adjustable current source IB1 includes: a first bias generating unit BIAS1 and a first branch adjustable unit IB1_1;

[0074] The first bias generating unit BIAS1 has an input terminal, a first output terminal, a second output terminal and a ground terminal. The input terminal of the first bias generating unit BIAS1 is connected to the external SOURCE terminal, the first bias signal is output through the first output terminal of the first bias generating unit BIAS1, and the second bias signal is output through the second output terminal of the first bias generating unit BIAS1; the ground terminal is grounded;

[0075] The first branch adjustable unit IB1_1 has a first input terminal, a second input terminal, a switch control terminal and a ground terminal. The first input terminal of the first branch adjustable unit IB1_1 is connected to the first output terminal of the first bias generating unit BIAS1, the second input terminal of the first branch adjustable unit IB1_1 is connected to the second output terminal of the first bias generating unit BIAS1, and the switch control terminal of the first branch adjustable unit IB1_1 is used to receive a first switching instruction; the first branch adjustable unit IB1_1 is used to generate a first adjustable current according to the first switching instruction.

[0076] like Figure 3 A circuit diagram of a first adjustable current source is shown, wherein the first bias generating unit BIAS1 comprises:

[0077] A first resistor R1 has a first end and a second end, and the first end of the first resistor R1 is connected to an external SOURCE end;

[0078] The seventeenth switch tube M17 has a gate, a source and a drain, the drain of the seventeenth switch tube M17 is connected to the second end of the first resistor R1; the gate of the seventeenth switch tube M17 is connected to the first output end of the first bias generating unit BIAS1;

[0079] The eighteenth switch tube M18 has a gate, a source and a drain. The drain of the eighteenth switch tube M18 is connected to the source of the seventeenth switch tube M17. The gate of the eighteenth switch tube M18 is respectively connected to the drain of the seventeenth switch tube M17 and the second output end of the first bias generating unit BIAS1. The source of the eighteenth switch tube M18 is grounded.

[0080] Figure 3 , the dotted line frame on the left is the first bias generating unit BIAS1, wherein the first end of the first resistor R1 inputs Iref provided by the external SOURCE end, the first resistor R1 is sequentially connected in series with the seventeenth switch tube M17 and the eighteenth switch tube M18, a first bias signal is derived through the gate of the seventeenth switch tube M17, and a second bias signal is derived through the gate of the eighteenth switch tube M18.

[0081] like Figure 3 As shown, the first branch adjustable unit IB1_1 includes: a first branch and at least one second branch;

[0082] The first branch includes:

[0083] The nineteenth switch tube M19 has a gate, a source and a drain, and the drain of the nineteenth switch tube M19 is connected to the drain of the second switch tube M2; the gate of the nineteenth switch tube M19 is connected to the first output end of the first bias generating unit BIAS1;

[0084] The twentieth switch tube M20 has a gate, a source and a drain, the drain of the twentieth switch tube M20 is connected to the source of the nineteenth switch tube M19; the gate of the twentieth switch tube M20 is connected to the second output end of the first bias generating unit BIAS1; the source of the twentieth switch tube M20 is grounded;

[0085] Each second branch includes:

[0086] The twenty-first switch tube M21 has a gate, a source and a drain, the drain of the twenty-first switch tube M21 is connected to the drain of the second switch tube M2; the gate of the twenty-first switch tube M21 is connected to the first output end of the first bias generating unit BIAS1;

[0087] The twenty-second switch tube M22 has a gate, a source and a drain. The drain of the twenty-second switch tube M22 is connected to the source of the twenty-first switch tube M21; the gate of the twenty-second switch tube M22 is connected to the second output terminal of the first bias generating unit BIAS1 through the first electronic switch; the gate of the twenty-second switch tube M22 is grounded through the second electronic switch; the source of the twenty-second switch tube M22 is grounded. The twenty-first switch tube M21 and the twenty-second switch tube M22 in each second branch can be the same as or different from the twenty-first switch tube M21 and the twenty-second switch tube M22 in other second branches.

[0088] like Figure 4 A circuit diagram of a first adjustable current source is shown, the dotted line frame on the right is the first branch adjustable unit IB1_1, and the figure takes 2-bit four-speed adjustable as an example for explanation, and more bit adjustable can be designed according to requirements; Figure 4 The portion of the dotted line frame on the right side of is a current mirror replicated in proportion, and switches S1 to S4 are used to control the currents of the branches of the first branch adjustable unit IB1_1 to achieve the change adjustment of the total current.

[0089] Figure 4 In the embodiment, the bias current Iref of the BIAS1 input of the first branch adjustable unit IB1_1 is the SOURCE current provided externally. When S1 and S3 are in the off state, and S2 and S4 are in the on state, only the first branch of the first branch adjustable unit IB1_1 is opened, and its current is I(fixed), that is, the first adjustable current generated by the first adjustable current source IB1 is I(fixed); when S1 and S4 are in the on state, and when S2 and S3 are in the off state, the current of the first branch adjustable unit IB1_1 is 2I , that is, the first adjustable current generated by the first adjustable current source IB1 is 2I; when S2 and S3 are on, when S1 and S4 are off, the current of the first branch adjustable unit IB1_1 is 3I, that is, the first adjustable current generated by the first adjustable current source IB1 is 3I; when S1 and S3 are on, when S2 and S4 are off, the current of the first branch adjustable unit IB1_1 is 4I, that is, the first adjustable current generated by the first adjustable current source IB1 is 4I; therefore, current regulation of I to 4I can be achieved. Its bit position and unit precision can be flexibly designed according to requirements.

[0090] Further, the second adjustable current source IB2 comprises: a second bias generating unit BIAS2 and a second branch adjustable unit IB2_1;

[0091] The second bias generating unit BIAS2 has a first output terminal, a second output terminal, a third output terminal and a power supply terminal. The first output terminal of the second bias generating unit BIAS2 is connected to the external SINK terminal, the power supply terminal of the second bias generating unit BIAS2 is connected to the power supply voltage, the third bias signal is output through the second output terminal of the second bias generating unit BIAS2, and the fourth bias signal is output through the third output terminal of the second bias generating unit BIAS2;

[0092] The second branch adjustable unit IB2_1 includes a first input terminal, a second input terminal, a switch control terminal and a power supply terminal. The first input terminal of the second branch adjustable unit IB2_1 is connected to the second output terminal of the second bias generating unit BIAS2, the second input terminal of the second branch adjustable unit IB2_1 is connected to the third output terminal of the second bias generating unit BIAS2, and the switch control terminal of the second branch adjustable unit IB2_1 is used to receive a second switching instruction; the second branch adjustable unit IB2_1 is used to generate a second adjustable current according to the second switching instruction.

[0093] like Figure 5 A circuit diagram of a second adjustable current source is shown, wherein the second bias generating unit BIAS2 comprises:

[0094] A second resistor R2 has a first end and a second end, and the first end of the second resistor is connected to an external SINK end;

[0095] The twenty-third switch tube M23 has a gate, a source and a drain, the drain of the twenty-third switch tube M23 is connected to the second end of the second resistor R2; the gate of the twenty-third switch tube M23 is connected to the third output end of the second bias generating unit BIAS2;

[0096] The twenty-fourth switch tube M24 has a gate, a source and a drain. The drain of the twenty-fourth switch tube M24 is connected to the source of the twenty-third switch tube M23. The gate of the twenty-fourth switch tube M24 is connected to the drain of the twenty-third switch tube M23. The source of the twenty-fourth switch tube M24 is connected to the power supply voltage VDD.

[0097] Figure 5 , the dotted line frame on the left is the second bias generating unit BIAS2, wherein the first end of the second resistor R2 inputs Iref provided by the external SINK terminal, the second resistor R2 is connected in series with the twenty-third switch tube M23 and the twenty-fourth switch tube M24 in sequence, the third bias signal is derived through the gate of the twenty-fourth switch tube M24, and the fourth bias signal is derived through the gate of the twenty-third switch tube M23.

[0098] Figure 5 In the embodiment, the second branch adjustable unit IB2_1 includes: a third branch and at least one fourth branch;

[0099] The third branch includes:

[0100] The twenty-fifth switch tube M25 has a gate, a source and a drain, and the drain of the twenty-fifth switch tube M25 is connected to the drain of the third switch tube M3; the gate of the twenty-fifth switch tube M25 is connected to the third output terminal of the second bias generating unit BIAS2;

[0101] The twenty-sixth switch tube M26 has a gate, a source and a drain, the drain of the twenty-sixth switch tube M26 is connected to the source of the twenty-fifth switch tube M25; the gate of the twenty-sixth switch tube M26 is connected to the second output end of the second bias generating unit BIAS2; the source of the twenty-sixth switch tube M26 is connected to the power supply voltage;

[0102] Each fourth leg includes:

[0103] The twenty-seventh switch tube M27 has a gate, a source and a drain, the drain of the twenty-seventh switch tube M27 is connected to the drain of the third switch tube M3; the gate of the twenty-seventh switch tube M27 is connected to the third output terminal of the second bias generating unit BIAS;

[0104] The twenty-eighth switch tube M28 has a gate, a source and a drain. The drain of the twenty-eighth switch tube M28 is connected to the source of the twenty-seventh switch tube M27; the gate of the twenty-eighth switch tube M28 is connected to the second output end of the second bias generating unit BIAS2 through a third electronic switch; the gate of the twenty-eighth switch tube M28 is connected to the power supply voltage VDD through a fourth electronic switch; the source of the twenty-eighth switch tube M28 is connected to the power supply voltage. The twenty-seventh switch tube M27 and the twenty-eighth switch tube M28 in each fourth branch may be the same as or different from the twenty-seventh switch tube M27 and the twenty-eighth switch tube M28 in other fourth branches.

[0105] like Figure 6 A circuit diagram of a second adjustable current source is shown, the portion of the dotted line box on the right is the second branch adjustable unit IB2_1, and the figure takes 2-bit four-speed adjustable as an example for explanation, and more bit adjustable can be designed according to requirements; Figure 6 The portion of the dotted line frame on the right side of is a current mirror replicated in proportion, and switches S5-S8 are used to control the current of each branch of the second branch adjustable unit IB2_1 to achieve the change adjustment of the total current.

[0106] Figure 6In the embodiment, the bias current Iref of the BIAS2 input of the second branch adjustable unit IB2_1 is the SINK current provided externally. When S5 and S7 are in the off state, S6 and S8 are in the on state, only the third branch of the second branch adjustable unit IB2_1 is opened, and its current is I(fixed), that is, the second adjustable current generated by the second adjustable current source IB2 is I(fixed); when S5 and S8 are in the on state, when S6 and S7 are in the off state, the current of the second branch adjustable unit IB2_1 is 2I, That is, the second adjustable current generated by the second adjustable current source IB2 is 2I; when S6 and S7 are on, when S5 and S8 are off, the current of the second branch adjustable unit IB2_1 is 3I, that is, the second adjustable current generated by the second adjustable current source IB2 is 3I; when S5 and S7 are on, when S6 and S8 are off, the current of the second branch adjustable unit IB2_1 is 4I, that is, the second adjustable current generated by the second adjustable current source IB2 is 4I; therefore, current regulation of I to 4I can be achieved. Its bit position and unit precision can be flexibly designed according to requirements.

[0107] For ease of understanding, the following Figure 2 , Figure 4 and Figure 6 Take this as an example to explain in detail. Figure 2 As shown, the first adjustable current source IB1 provides current for the first switch tube M1 and the second switch tube M2 branches connected by diodes. The first switch tube M1 and the second switch tube M2 must work in the saturation region, and the first sub-voltage VBP can be obtained as:

[0108]

[0109] Among them, V GS1 represents the gate-source voltage of the first switch tube M1; V GS2 represents the gate-source voltage of the second switch tube M2; IB1 represents the first adjustable current generated by the first adjustable current source IB1; Kp is a fixed parameter value related to the manufacturing process of the PMOS switch tube; W1 / L1 represents the width-to-length ratio of the first switch tube M1; V THP is the threshold voltage of the PMOS switch tube; W2 / L2 represents the width-to-length ratio of the second switch tube M2;

[0110] Since it is a fully differential structure, that is, the first current source IB3 is the same as the second current source IB4, V GS13 =V GS15 ,so:

[0111] V A =V C =VBP+|V GS13 |=VBP+|V GS15 |;

[0112] Among them, V A Represents the voltage of node A; V C Represents the voltage at node C; V GS13 represents the gate-source voltage of the ninth switch tube M13; V GS15 represents the gate-source voltage of the eleventh switch tube M15;

[0113] Therefore, the current of ClassAB output tubes M5 and M7 (working in the saturation region) is:

[0114]

[0115] Among them, I d5 I represents the drain current of the thirteenth switch tube M5; d7 represents the drain current of the fifteenth switch tube M7; W5 / L5 represents the width-to-length ratio of the thirteenth switch tube M5;

[0116] Similarly, the second sub-voltage VBN is obtained as:

[0117]

[0118] Among them, V GS3 represents the gate-source voltage of the third switch tube M3; V GS4 represents the gate-source voltage of the fourth switch tube M4; IB2 represents the second adjustable current generated by the second adjustable current source IB2; K N is a fixed parameter value related to the manufacturing process of the NMOS switch tube; W3 / L3 represents the width-to-length ratio of the third switch tube M3; V THN is the threshold voltage of the NMOS switch tube; W4 / L4 represents the width-to-length ratio of the fourth switch tube M4;

[0119] V B =V D =VBN-V GS14 =VBN-V GS16 ;

[0120] Among them, V B Represents the voltage of node B; V D Represents the voltage at node D; V GS14 represents the gate-source voltage of the tenth switch tube M14; V GS16 represents the gate-source voltage of the twelfth switch tube M16;

[0121]

[0122] Among them, I d6 I represents the drain current of the fourteenth switch tube M6; d8represents the drain current of the sixteenth switch tube M8; W6 / L6 represents the width-to-length ratio of the fourteenth switch tube M6;

[0123] Therefore, it can be obtained that the quiescent current output by ClassAB is a function of the first adjustable current generated by the first adjustable current source IB1 and the second adjustable current generated by the first adjustable current source IB2, and the quiescent current output by ClassAB can be controlled by trimming the currents of IB1 and IB2; Figure 2 In the figure, Vout+ / - is the output terminal of ClassAB.

[0124] In the static state, the ninth switch tube M13 and the tenth switch tube M14 flow through half of the branch current respectively, and the eleventh switch tube M15 and the twelfth switch tube M16 flow through half of the branch current respectively. If IB3=IB4=m*IB1, that is, the first sub-current generated by the first current source IB3 and the second sub-current generated by the second current source IB4 are both m times the first adjustable current generated by the first adjustable current source IB1, I d13 =I d15 =m / 2*IB1, the second switch tube M2 and the ninth switch tube M13 and the eleventh switch tube M15 are mirror tubes, that is, V GS2 =V GS13 =V GS15 , then the thirteenth switch tube M5, the sixteenth switch tube M7 and the first switch tube M1 are also mirror tubes, and the static current output by them can be determined by their proportional coefficients. The magnitude of the first adjustable current generated by the first adjustable current source IB1 and the second adjustable current generated by the second adjustable current source IB2 can be adjusted by Figure 3 and Figure 5 method to achieve this.

[0125] The above-mentioned Class-AB operational amplifier circuit provides a fully differential operational amplifier structure with adjustable ClassAB output stage current. The first adjustable current source IB1 and the second adjustable current source IB2 can be trimmed to change the first sub-voltage VBP and the first sub-voltage VBN. If the first adjustable current generated by the first adjustable current source IB1 and the second adjustable current generated by the second adjustable current source IB2 are increased, the first sub-voltage VBP decreases, the second sub-voltage VBN increases, the voltages of nodes A and C decrease, and the voltages of nodes B and D increase, so that the Class-AB output current increases, otherwise it decreases, thereby achieving a function of adjusting the output current. This circuit can change the bias voltage of the Class-AB output tube through a simple current trim, thereby achieving flexible adjustment of the static current of the output stage. This allows this circuit technology to meet application scenarios with different power consumption and linearity requirements, and has good stability, a large dynamic range, and good power consumption control capabilities. The adjustment method of this circuit is flexible and practical, and can achieve multi-bit, high-precision regulation, with strong driving capabilities. The output stage bias voltage is biased by a floating current source. By adjusting the bias voltage, the static operating point of the circuit can be kept normal under different process angles.

[0126] The present invention provides a Class-AB operational amplifier system, comprising any one of the above-mentioned Class-AB operational amplifier circuits.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has 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 with equivalents. However, 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 invention.

Claims

1. A Class-AB operational amplifier circuit, characterized in that: The circuit comprises: A current adjustable module, used for receiving a current adjustment instruction, and outputting an adjusted first voltage signal according to the current adjustment instruction; A current source module, used for generating a current signal; a voltage adjustment module, configured to receive the first voltage signal and the current signal, and generate an adjusted bias voltage signal according to the first voltage signal and the current signal; A Class-AB output module, used to receive the adjusted bias voltage signal, and adjust the output current of the Class-AB operational amplifier according to the adjusted bias voltage signal; The current adjustable module includes: a first adjustable current branch and a second adjustable current branch; the first voltage signal includes: a first sub-voltage and a second sub-voltage; The first adjustable current branch comprises: A first switch tube, comprising a gate, a source and a drain, wherein the source is connected to a power supply voltage, and the gate is connected to the drain; A first adjustable current source has a first end and a second end, wherein the first end of the first adjustable current source is grounded; and is used to receive a current adjustment instruction and generate a first adjustable current according to the current adjustment instruction; a second switch tube, having a gate, a source and a drain, the source of the second switch tube being connected to the drain of the first switch tube, the drain of the second switch tube being respectively connected to the gate of the second switch tube and the second end of the first adjustable current source, and being used to output the first sub-voltage through the gate of the second switch tube according to the first adjustable current; The second adjustable current branch comprises: A second adjustable current source has a first end and a second end, the first end of the second adjustable current source is connected to the power supply voltage; and is used to receive a current adjustment instruction and generate a second adjustable current according to the current adjustment instruction; a third switch tube, having a gate, a source and a drain, wherein the drain of the third switch tube is respectively connected to the second end of the second adjustable current source and the gate of the third switch tube; and is used to output the second sub-voltage through the gate of the third switch tube according to the second adjustable current; The fourth switch tube has a gate, a source and a drain, the drain of the fourth switch tube is respectively connected to the source of the third switch tube and the gate of the fourth switch tube; the source of the fourth switch tube is grounded.

2. The circuit according to claim 1, characterized in that The current signal includes: a first sub-current and a second sub-current; the first sub-current is the same as the second sub-current; the current source module includes a first current source and a second current source; The first current source has a first end and a second end, the first end of the first current source is connected to the voltage adjustment module, and the second end of the first current source is grounded; and is used to generate the first sub-current; The second current source has a first end and a second end, the first end of the second current source is connected to the voltage adjustment module, and the second end of the second current source is grounded; and is used to generate the second sub-current.

3. The circuit according to claim 2, characterized in that The voltage adjustment module comprises: a fifth switch tube, comprising a gate, a source and a drain, wherein the source of the fifth switch tube is connected to a power supply voltage; a sixth switch tube, comprising a gate, a source and a drain, wherein the source of the sixth switch tube is connected to the power supply voltage, and the gate of the sixth switch tube is connected to the gate of the fifth switch tube; a seventh switch tube, having a gate, a source and a drain, wherein the source of the seventh switch tube is respectively connected to the drain of the fifth switch tube and the first output end of the previous stage circuit; an eighth switch tube, having a gate, a source and a drain, wherein the gate of the eighth switch tube is connected to the gate of the seventh switch tube, and the source of the eighth switch tube is respectively connected to the drain of the sixth switch tube and the second output end of the previous stage circuit; the first output end and the second output end are used to output the differential signal output by the previous stage circuit; a ninth switch tube, comprising a gate, a source and a drain, wherein the source of the ninth switch tube is connected to the drain of the seventh switch tube, the gate of the ninth switch tube is connected to the gate of the second switch tube; and the drain of the ninth switch tube is connected to the first end of the first current source; a tenth switch tube, comprising a gate, a source and a drain, wherein the drain of the tenth switch tube is connected to the drain of the seventh switch tube, the gate of the tenth switch tube is connected to the gate of the third switch tube; and the source of the tenth switch tube is connected to the first end of the first current source; an eleventh switch tube, comprising a gate, a source and a drain, wherein the source of the eleventh switch tube is connected to the drain of the eighth switch tube, the gate of the eleventh switch tube is connected to the gate of the second switch tube; and the drain of the eleventh switch tube is connected to the first end of the second current source; The twelfth switch tube has a gate, a source and a drain, the drain of the twelfth switch tube is connected to the drain of the eighth switch tube, the gate of the twelfth switch tube is connected to the gate of the third switch tube; the source of the twelfth switch tube is connected to the first end of the second current source.

4. The circuit according to claim 3, characterized in that The Class-AB output module includes: A thirteenth switch tube, comprising a gate, a source and a drain, wherein the source of the thirteenth switch tube is connected to a power supply voltage; and the gate of the thirteenth switch tube is connected to the drain of the seventh switch tube; a fourteenth switch tube, having a gate, a source and a drain, the drain of the fourteenth switch tube being respectively connected to the drain of the thirteenth switch tube and the third output terminal of the Class-AB output module, the gate of the fourteenth switch tube being connected to the first terminal of the first current source, and the source of the fourteenth switch tube being grounded; a fifteenth switch tube, having a gate, a source and a drain, wherein the source of the fifteenth switch tube is connected to the power supply voltage; and the gate of the fifteenth switch tube is connected to the drain of the eighth switch tube; The sixteenth switch tube has a gate, a source and a drain. The drain of the sixteenth switch tube is respectively connected to the drain of the fifteenth switch tube and the fourth output end of the Class-AB output module. The gate of the sixteenth switch tube is connected to the first end of the second current source, and the source of the sixteenth switch tube is grounded.

5. The circuit according to claim 1, characterized in that The first adjustable current source comprises: The first bias generating unit has an input terminal, a first output terminal, a second output terminal and a ground terminal, wherein the input terminal of the first bias generating unit is connected to an external SOURCE The first bias generating unit is connected to the first output terminal of the first bias generating unit, outputs a first bias signal through the first output terminal of the first bias generating unit, and outputs a second bias signal through the second output terminal of the first bias generating unit; the ground terminal is grounded; The first branch adjustable unit has a first input terminal, a second input terminal, a switch control terminal and a ground terminal. The first input terminal of the first branch adjustable unit is connected to the first output terminal of the first bias generating unit. The second input terminal of the first branch adjustable unit is connected to the second output terminal of the first bias generating unit. The switch control terminal of the first branch adjustable unit is used to receive a first switch instruction. The first branch adjustable unit is used to generate a first adjustable current according to the first switch instruction.

6. The circuit according to claim 5, characterized in that The first bias generating unit comprises: A first resistor having a first end and a second end, wherein the first end of the first resistor is connected to an external SOURCE end; a seventeenth switch tube, having a gate, a source and a drain, wherein the drain of the seventeenth switch tube is connected to the second end of the first resistor; and the gate of the seventeenth switch tube is connected to the first output end of the first bias generating unit; The eighteenth switch tube has a gate, a source and a drain, the drain of the eighteenth switch tube is connected to the source of the seventeenth switch tube; the gate of the eighteenth switch tube is respectively connected to the drain of the seventeenth switch tube and the second output end of the first bias generating unit; the source of the eighteenth switch tube is grounded.

7. The circuit according to claim 5, characterized in that The first branch adjustable unit comprises: a first branch and at least one second branch; The first branch comprises: A nineteenth switch tube, comprising a gate, a source and a drain, wherein the drain of the nineteenth switch tube is connected to the drain of the second switch tube; and the gate of the nineteenth switch tube is connected to the first output end of the first bias generating unit; A twentieth switch tube, having a gate, a source and a drain, wherein the drain of the twentieth switch tube is connected to the source of the nineteenth switch tube; the gate of the twentieth switch tube is connected to the second output end of the first bias generating unit; and the source of the twentieth switch tube is grounded; Each of the second branches comprises: a twenty-first switch tube, having a gate, a source and a drain, wherein the drain of the twenty-first switch tube is connected to the drain of the second switch tube; and the gate of the twenty-first switch tube is connected to the first output end of the first bias generating unit; The twenty-second switch tube has a gate, a source and a drain, the drain of the twenty-second switch tube is connected to the source of the twenty-first switch tube; the gate of the twenty-second switch tube is connected to the second output end of the first bias generating unit through a first electronic switch; the gate of the twenty-second switch tube is grounded through a second electronic switch; and the source of the twenty-second switch tube is grounded.

8. The circuit according to claim 1, characterized in that The second adjustable current source comprises: The second bias generating unit has a first output terminal, a second output terminal, a third output terminal and a power supply terminal, wherein the first output terminal of the second bias generating unit is connected to an external SINK The power supply terminal of the second bias generating unit is connected to the power supply voltage, a third bias signal is output through the second output terminal of the second bias generating unit, and a fourth bias signal is output through the third output terminal of the second bias generating unit; The second branch adjustable unit comprises a first input terminal, a second input terminal, a switch control terminal and a power supply terminal, wherein the first input terminal of the second branch adjustable unit is connected to the second output terminal of the second bias generating unit, the second input terminal of the second branch adjustable unit is connected to the third output terminal of the second bias generating unit, and the switch control terminal of the second branch adjustable unit is used to receive a second switch instruction; the second branch adjustable unit is used to generate a second adjustable current according to the second switch instruction.

9. The circuit according to claim 8, characterized in that The second bias generating unit comprises: A second resistor has a first end and a second end, wherein the first end of the second resistor is connected to an external SINK end; a twenty-third switch tube, having a gate, a source and a drain, wherein the drain of the twenty-third switch tube is connected to the second end of the second resistor; and the gate of the twenty-third switch tube is connected to the third output end of the second bias generating unit; The twenty-fourth switch tube has a gate, a source and a drain. The drain of the twenty-fourth switch tube is connected to the source of the twenty-third switch tube. The gate of the twenty-fourth switch tube is connected to the drain of the twenty-third switch tube. The source of the twenty-fourth switch tube is connected to the power supply voltage.

10. The circuit according to claim 8, characterized in that The second branch adjustable unit includes: a third branch and at least one fourth branch; The third branch comprises: a twenty-fifth switch tube, having a gate, a source and a drain, wherein the drain of the twenty-fifth switch tube is connected to the drain of the third switch tube; and the gate of the twenty-fifth switch tube is connected to the third output terminal of the second bias generating unit; a twenty-sixth switch tube, having a gate, a source and a drain, wherein the drain of the twenty-sixth switch tube is connected to the source of the twenty-fifth switch tube; the gate of the twenty-sixth switch tube is connected to the second output end of the second bias generating unit; and the source of the twenty-sixth switch tube is connected to a power supply voltage; Each of the fourth branches comprises: a twenty-seventh switch tube, having a gate, a source and a drain, wherein the drain of the twenty-seventh switch tube is connected to the drain of the third switch tube; and the gate of the twenty-seventh switch tube is connected to the third output terminal of the second bias generating unit; The twenty-eighth switch tube has a gate, a source and a drain, the drain of the twenty-eighth switch tube is connected to the source of the twenty-seventh switch tube; the gate of the twenty-eighth switch tube is connected to the second output end of the second bias generating unit through a third electronic switch; the gate of the twenty-eighth switch tube is connected to the power supply voltage through a fourth electronic switch; and the source of the twenty-eighth switch tube is connected to the power supply voltage.

11. A Class-AB operational amplifier system, characterized in that: A Class-AB operational amplifier circuit comprising any one of claims 1-10.

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