Band-gap reference voltage circuit with multistage curvature compensation and chip

Abstract

The embodiment of the invention provides a multistage curvature compensation band-gap reference voltage circuit which comprises a first-order temperature compensation circuit and a high-order curvature compensation circuit, the first-order temperature compensation circuit and the high-order curvature compensation circuit are separated and decoupled, and the high-order curvature compensation circuit is formed by cascading a plurality of VBE nonlinear compensation circuits. The first-order temperature compensation circuit is configured to compensate a linear relation generated by VBE and temperature change, and the high-order curvature compensation circuit is configured to compensate a nonlinear relation generated by VBE and temperature change.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the field of integrated circuit technology, and in particular, to a bandgap reference voltage circuit and chip with multi-level curvature compensation. Background Art

[0002] The bandgap reference voltage source is a core component in modern precision measurement systems. Its function is to provide a stable reference voltage with small temperature drift. Usually, the temperature drift of the bandgap reference voltage will be compensated by the first order. However, due to process deviations (such as errors in semiconductor manufacturing) and process variations (such as production fluctuations in different batches), simple first-order compensation cannot achieve very low temperature drift and cannot meet the requirement of temperature drift below 30ppm / ℃. Therefore, the residual curvature after the first-order compensation becomes the main source of temperature drift, and the curvature is usually dominated by the nonlinearity of the base-emitter voltage (VBE) of the substrate PNP. In order to reduce this curvature, a bandgap reference voltage source with high-order curvature compensation is proposed in the prior art.

[0003] Figure 1 Schematic diagram of the circuit structure of high-order curvature compensation in the prior art. Figure 1 As shown, on the basis of first-order compensation, resistors R41, R42, current source and BJT (Q2) are added, and the VBE model after high-order curvature compensation is: Among them, Vg0 is a constant that is independent of temperature; Tr is the reference temperature, which is usually set to 300K (27℃) for the convenience of testing and application. XTI is a process-related parameter in the BJT characteristics. In CMOS processes, this value is usually between 2 and 4. β describes the order of the BJT's temperature-varying characteristics. If the BJT (Q2) is biased with a positive temperature coefficient (PTAT) current, β=1; if the BJT is biased by a zero temperature coefficient (ZTC) current, β=0; similarly, if the BJT is biased by a negative temperature coefficient (NTC) current, β<0. In the above formula, the second term is linearly related to temperature, so it can be compensated by the first-order positive temperature coefficient voltage generated by ΔVBE, and the third term includes Tln (T / Tr) which is nonlinear with respect to temperature. Refer to Figure 1 As shown, Q0 and Q1 are biased by PTAT current, and Q2 is biased by ZTC current, where PTAT current and ZTC current are equal at temperature Tr. Therefore, the VBE voltages of Q0 and Q2 are:

[0004]

[0005]

[0006] Therefore, the VBE voltage difference between Q0 and Q2 is:

[0007] The current formed by the voltage difference on R42 will flow through R1 and R3. Similarly, the same current will flow through R2 and R3 on R41. Therefore, the final output Vbg_out becomes:

[0008]

[0009] After similar items are combined:

[0010]

[0011] The second term is linearly related to temperature T, so the PTAT voltage generated by ΔVBE can be completely offset by adjusting R3. The fourth term is nonlinearly related to temperature and can be compensated by adjusting the ratio of R3 to R41, R3 / R41.

[0012] However, the method of high-order curvature compensation is limited by its own structure and it is difficult to achieve ideal results in practical applications. Since R3 determines both the offset of linear terms and the offset of nonlinear terms, when the R3 value is adjusted to offset the linear terms, the proportion of the nonlinear terms is also changed, so it is impossible to optimize the offset of the nonlinear terms, and vice versa. Therefore, the curvature compensation circuit can only reduce the temperature drift to about 12ppm / ℃, which is still difficult to meet the requirements of high-performance precision measurement systems (such as precision measurement equipment, aerospace, instrumentation, etc.) below 5ppm / ℃. Summary of the invention

[0013] The embodiments described herein provide a bandgap reference voltage circuit and chip with multi-level curvature compensation.

[0014] According to a first aspect of the present disclosure, there is provided a bandgap reference voltage circuit with multi-stage curvature compensation, comprising: a first-order temperature compensation circuit and a high-order curvature compensation circuit, wherein the first-order temperature compensation circuit is separated and decoupled from the high-order curvature compensation circuit, the high-order curvature compensation circuit being composed of a plurality of VBE nonlinear compensation circuits cascaded, the first-order temperature compensation circuit being configured to compensate for the linear relationship between VBE and temperature variation, and the high-order curvature compensation circuit being configured to compensate for the nonlinear relationship between VBE and temperature variation.

[0015] In some embodiments of the present disclosure, a first-order temperature compensation circuit includes: a first operational amplifier, a first PMOS transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a first PNP tube and a second PNP tube; one end of the fourth resistor is connected to the drain of the first PMOS transistor, and the other end is respectively connected to the second resistor and the third resistor; the output end of the first operational amplifier is connected to the gate of the first PMOS transistor, the first input end of the first operational amplifier is connected to the common connection end of the first resistor and the third resistor, and the second input end of the first operational amplifier is connected to the common connection end of the second resistor and the first PNP tube; one end of the first resistor is connected to the third resistor, and the other end is connected to the emitter of the second PNP tube; one end of the second resistor is connected to the common connection end of the third resistor and the fourth resistor, and the other end is connected to the emitter of the first PNP tube; the base of the first PNP tube is connected to the base of the second PNP tube; the base and collector of the first PNP tube and the second PNP tube are grounded.

[0016] In some embodiments of the present disclosure, the first operational amplifier and the first PMOS transistor form negative feedback so that the voltage at the first input terminal of the first operational amplifier is equal to the voltage at the second input terminal, the resistance value of the fourth resistor is adjustable, and first-order temperature compensation is achieved by adjusting the resistance value of the fourth resistor.

[0017] In some embodiments of the present disclosure, a size ratio of the first PNP transistor to the second PNP transistor is 1:n, where n is an integer greater than 1.

[0018] In some embodiments of the present disclosure, the VBE nonlinear compensation circuit includes: a second operational amplifier, an NMOS transistor, a second PMOS transistor, a third PNP tube, a fourth PNP tube, a PTAT current source, a compensation current source and a bias current source; the PTAT current source is connected to the emitter of the third PNP tube, and is used to provide a bias current for the third PNP tube; the compensation current source is respectively connected to the drain of the NMOS transistor and the gate of the second PMOS transistor, and is used to provide a bias current for the fourth PNP tube; the source of the NMOS transistor is connected to the emitter of the fourth PNP transistor, the drain of the second PMOS transistor is connected to the bias current source, and the other end of the bias current source is grounded; the first input end of the second operational amplifier is connected to the emitter of the third PNP tube, the second input end of the second operational amplifier is connected to the emitter of the fourth PNP tube, and the output end of the second operational amplifier is connected to the gate of the NMOS transistor; the collectors of the third PNP tube and the fourth PNP tube are grounded.

[0019] In some embodiments of the present disclosure, the second operational amplifier and the NMOS transistor form a first negative feedback to make the emitter voltages of the third PNP tube and the fourth PNP tube equal; the NMOS transistor, the fourth PNP tube, the PTAT current source, the second PMOS transistor and the bias current source form a second negative feedback to make the base of the fourth PNP tube serve as a voltage output terminal.

[0020] In some embodiments of the present disclosure, the temperature characteristic of the compensation current source is a zero temperature coefficient or a negative temperature coefficient, the currents generated by the PTAT current source and the compensation current source are equal at the reference temperature, and high-order curvature compensation is achieved by adjusting the temperature characteristics of the compensation current and the number of cascades of the VBE nonlinear compensation circuit.

[0021] In some embodiments of the present disclosure, the nonlinear compensation amount of each stage of the VBE nonlinear compensation circuit is:

[0022]

[0023] Wherein, VBE(Qa)-VBE(Qb) is the base-emitter voltage difference between the third PNP tube and the fourth PNP tube, Tr is the reference temperature, K is the Boltzmann constant, q is the electron charge constant, T is the absolute temperature, and γ is the temperature characteristic of the compensation current source;

[0024] Through multi-stage cascading, the output voltage of the bandgap reference voltage source is:

[0025]

[0026] Wherein, Vg0 is a constant independent of temperature, Tr is the reference temperature, K is the Boltzmann constant, q is the electron charge value constant, T is the absolute temperature, γ is the temperature characteristic of the compensation current source, XTI is a process-related parameter, m is the number of cascades of the VBE nonlinear compensation circuit, VBE is the voltage drop between the base and the emitter, and ΔVBE is the base-emitter voltage difference between the first PNP tube and the second PNP tube.

[0027] According to a second aspect of the present disclosure, a chip is provided, comprising the multi-stage curvature compensated bandgap reference voltage circuit according to the first aspect of the present disclosure.

[0028] According to a third aspect of the present disclosure, an electronic device is provided, comprising the chip according to the second aspect of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly described below. It should be noted that the drawings described below only relate to some embodiments of the present disclosure, but are not intended to limit the present disclosure, wherein:

[0030] Figure 1 It is a schematic diagram of the circuit structure of high-order curvature compensation in the prior art;

[0031] Figure 2 is a schematic block diagram of a bandgap reference voltage circuit 100 with multi-stage curvature compensation according to an embodiment of the present disclosure;

[0032] Figure 3 is a schematic block diagram of a first-order temperature compensation circuit 110 according to an embodiment of the present disclosure;

[0033] Figure 4 An exemplary circuit diagram showing a VBE nonlinear compensation circuit according to an embodiment of the present disclosure;

[0034] Figure 5 This is a comparison chart of the voltage performance of the first-order temperature compensation circuit and the high-order curvature compensation circuit.

[0035] It should be noted that the elements in the drawings are schematic and not drawn to scale. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work also fall within the scope of protection of the present disclosure.

[0037] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person skilled in the art to which the subject matter of the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art, and will not be interpreted in an idealized or overly formal form unless otherwise explicitly defined herein. As used herein, a statement that two or more parts are "connected" or "coupled" together shall mean that the parts are joined together directly or through one or more intermediate components.

[0038] The embodiments of the present disclosure propose a multi-level curvature compensated bandgap reference voltage circuit, which achieves precise control of temperature changes by combining first-order and high-order temperature compensation mechanisms, thereby generating a reference voltage with minimal impact of temperature changes (temperature drift less than 5ppm / °C).

[0039] Figure 2 is a schematic block diagram of a bandgap reference voltage circuit 100 with multi-stage curvature compensation according to an embodiment of the present disclosure. Figure 2 In the example of , the multi-stage curvature compensated bandgap reference voltage circuit 100 includes: a first-order temperature compensation circuit 110 and a high-order curvature compensation circuit 120, wherein the first-order temperature compensation circuit 110 is separated and decoupled from the high-order curvature compensation circuit 120, and the high-order curvature compensation circuit 120 is composed of a plurality of VBE nonlinear compensation circuits (VBE nonlinear compensation circuit 1, VBE nonlinear compensation circuit 2, ... VBE nonlinear compensation circuit m) in cascade, and the first-order temperature compensation circuit 110 is configured to compensate for the linear relationship between VBE and temperature change to eliminate the linear temperature dependence in the reference voltage, that is, to eliminate the reference voltage fluctuation caused by the linear change of VBE with temperature. The high-order curvature compensation circuit 120 is configured to compensate for the nonlinear relationship between VBE and temperature change to eliminate the nonlinear change caused by temperature, that is, to compensate for the secondary or higher-order temperature effect of the base-emitter voltage VBE in different temperature ranges.

[0040] In the above circuit design, the first-order temperature compensation circuit and the high-order curvature compensation circuit are separated and decoupled. This means that the first-order compensation circuit and the high-order compensation circuit handle different temperature dependence problems respectively, without interfering with each other, thus avoiding the mutual influence that may occur during the compensation process. The benefit of the decoupled design is that each circuit module focuses on its specific temperature effect, making the overall compensation more accurate and efficient.

[0041] Figure 3 is a schematic block diagram of a first-order temperature compensation circuit 110 according to an embodiment of the present disclosure. Figure 3 As shown, the first-order temperature compensation circuit 110 includes: a first operational amplifier A0, a first PMOS transistor Mp0, a first resistor R0, a second resistor R1, a third resistor R2, a fourth resistor R3, a first PNP transistor Q0 and a second PNP transistor Q1. One end of the fourth resistor R3 is connected to the drain of the first PMOS transistor Mp0, and the other end is respectively connected to the second resistor R1 and the third resistor R2; the output end of the first operational amplifier A0 is connected to the gate of the first PMOS transistor Mp0, the first input end (positive input end) of the first operational amplifier A0 is connected to the common connection end of the first resistor R0 and the third resistor R2, and the second input end (negative input end) of the first operational amplifier A0 is connected to the common connection end of the second resistor R1 and the first PNP tube Q0; one end of the first resistor R0 is connected to the third resistor R2, and the other end is connected to the emitter of the second PNP tube Q1; one end of the second resistor R1 is connected to the common connection end of the third resistor R2 and the fourth resistor R3, and the other end is connected to the emitter of the first PNP tube Q0; the base of the first PNP tube Q0 is connected to the base of the second PNP tube Q1; the base and collector of the first PNP tube Q0 and the second PNP tube Q1 are grounded.

[0042] The first operational amplifier A0 and the first PMOS transistor Mp0 form negative feedback, so that the first input terminal voltage of the first operational amplifier A0 is equal to the second input terminal voltage, that is, V1=V2, and the resistance value of the fourth resistor R3 is adjustable. First-order temperature compensation can be achieved by adjusting the resistance value of the fourth resistor R3.

[0043] Specifically, since V1=V2, the current flowing through the first resistor R0 is ΔVBE / R0, where ΔVBE is the base-emitter voltage difference between the first PNP transistor Q0 and the second PNP transistor Q1. Figure 2 In the circuit shown, assuming R1 = R2, the output voltage formula is:

[0044]

[0045] VBE is the base-emitter voltage. Since VBE has a negative temperature coefficient characteristic and ΔVBE has a first-order positive temperature coefficient characteristic, adjusting R3 can adjust the ratio of the negative temperature coefficient to the positive temperature coefficient, thereby making Vbg_out first-order stable with temperature.

[0046] It should be noted that the size ratio of the first PNP transistor Q0 and the second PNP transistor Q1 is 1:n, where n is an integer greater than 1. Therefore, the different current densities of Q1 and Q0 will lead to differences in their VBE (base-emitter voltage). This difference changes with temperature, and this difference can be used to adjust temperature compensation.

[0047] Figure 4 FIG. 1 shows an exemplary circuit diagram of a VBE nonlinear compensation circuit according to an embodiment of the present disclosure. Figure 4 In the example, the VBE nonlinear compensation circuit includes: a second operational amplifier A1, an NMOS transistor Mn0, a second PMOS transistor Mp1, a third PNP tube Qa, a fourth PNP tube Qb, a PTAT current source Iptat, a compensation current source Icor and a bias current source Ibias. Among them, the PTAT current source Iptat provides a current proportional to the temperature, and the compensation current source Icor is used to provide a current with a temperature characteristic of a zero temperature coefficient (ZTC) or a negative temperature coefficient (NTC). The output current of the compensation current source Icor is compared and adjusted with the current change of the PTAT current source as the temperature changes. At the reference temperature, the currents generated by the PTAT current source and the compensation current source are equal, and high-order curvature compensation is achieved by adjusting the temperature characteristics of the compensation current and the number of cascades of the VBE nonlinear compensation circuit.

[0048] The PTAT current source Iptat is connected to the emitter of the third PNP transistor Qa, and is used to provide a bias current for the third PNP transistor Qa. The compensation current source Icor is respectively connected to the drain of the NMOS transistor Mn0 and the gate of the second PMOS transistor Mp1, and is used to provide a bias current for the fourth PNP transistor Qb. The source of the NMOS transistor Mn0 is connected to the emitter of the fourth PNP transistor Qb, the drain of the second PMOS transistor Mp1 is connected to the bias current source Ibias and the base of Qb, and the other end of the bias current source Ibias is grounded. The first input terminal (positive input terminal) of the second operational amplifier A1 is connected to the emitter of the third PNP transistor Qa, the second input terminal (negative input terminal) of the second operational amplifier A1 is connected to the emitter of the fourth PNP transistor Qb, and the output terminal of the second operational amplifier A1 is connected to the gate of the NMOS transistor Mn0; the collectors of the third PNP transistor Qa and the fourth PNP transistor Qb are grounded.

[0049] exist Figure 4 In the example, the second operational amplifier A1 and the NMOS transistor Mn0 form a first negative feedback, so that the emitter voltages of the third PNP tube Qa and the fourth PNP tube Qb are equal, that is, Vea=Veb. The source of the NMOS transistor Mn0 is connected to the emitter of the fourth PNP tube Qb, the drain is connected to the compensation current source, and the gate is controlled by the output terminal of the second operational amplifier A1. The drain of the second PMOS transistor Mp1 is connected to the bias current source and the base of Qb, and the gate is connected to the compensation current source, and the output impedance is reduced by feedback. Therefore, the NMOS transistor Mn0, the fourth PNP tube Qb, the compensation current Icor, the second PMOS transistor Mp1 and the bias current source Ibias form a second negative feedback, so that the base of the fourth PNP tube Qb serves as the voltage output terminal Vout, so that the circuit can stabilize the output voltage.

[0050] according to Figure 4 In the circuit provided, the VBE of the third PNP tube Qa and the fourth PNP tube Qb are:

[0051]

[0052] Assuming XTI = 4.6, setting m = 3, and γ = -0.2, it means that Qb is biased by a negative temperature coefficient current in this embodiment. Since the emitter voltages of Qa and Qb are equal, the VBE voltage difference between Qa and Qb will be reflected on Vout-Vin, that is:

[0053]

[0054] Among them, VBE(Qa)-VBE(Qb) is the base-emitter voltage difference between the third PNP tube and the fourth PNP tube, which is the single-stage VBE nonlinear compensation amount, Tr is the reference temperature, K is the Boltzmann constant, q is the electron charge value constant, T is the absolute temperature, and γ is the temperature characteristic of the compensation current source.

[0055] Through multi-stage cascading, the final bandgap reference voltage source output voltage is:

[0056]

[0057] After sorting:

[0058]

[0059] Wherein, Vg0 is a constant independent of temperature, Tr is the reference temperature, K is the Boltzmann constant, q is the electron charge value constant, T is the absolute temperature, γ is the temperature characteristic of the compensation current source, XTI is a process-related parameter, m is the number of cascades of the VBE nonlinear compensation circuit, VBE is the voltage drop between the base and the emitter, and ΔVBE is the base-emitter voltage difference between the first PNP tube and the second PNP tube.

[0060] Compared with changing R3, the embodiment of the present disclosure uses m(1-γ)*KT / q*lnT to offset the nonlinear term in the above formula, so that R3 can only be used to offset the linear term without affecting the nonlinear term. Therefore, by adjusting the values ​​of m, γ and R3 separately, the reference source obtains the optimal output.

[0061] Figure 5 This is a comparison chart of the voltage performance of the first-order temperature compensation circuit and the high-order curvature compensation circuit. Figure 5 In the example, the dotted line shows the relationship curve between the output voltage of the reference source with first-order compensation and the temperature change, and the solid line shows the relationship curve between the output voltage of the reference source with multi-level curvature compensation and the temperature change. Comparing the dotted line and the solid line, the performance of the reference source provided by the embodiment of the present disclosure is significantly improved.

[0062] The embodiment of the present disclosure further provides a chip. The chip includes a bandgap reference voltage circuit with multi-level curvature compensation according to the embodiment of the present disclosure. The chip is, for example, a chip for providing a high-precision and high-stability reference voltage.

[0063] The embodiments of the present disclosure also provide an electronic device. The electronic device includes a chip according to the embodiments of the present disclosure. The electronic device is, for example, a high-performance precision measurement system such as precision measurement equipment, aerospace equipment, and industrial instrumentation.

[0064] In summary, according to the multi-stage curvature compensated bandgap reference voltage circuit of the embodiment of the present disclosure, the first-order temperature compensation circuit specifically compensates for the linear relationship between VBE and temperature change, which can effectively reduce the basic error caused by temperature change. The high-order curvature compensation circuit compensates for the nonlinear relationship between VBE and temperature change through multiple cascaded VBE nonlinear compensation circuits, thereby significantly reducing the high-order temperature effect (such as the nonlinear effect of temperature on the bandgap voltage). This technical solution that combines linear compensation and nonlinear compensation enables the circuit to maintain better temperature stability over a wider temperature range, especially in an environment with large temperature changes, and can provide a more accurate reference voltage. Compared with the traditional bandgap reference voltage circuit, it can better cope with complex temperature change characteristics, provide a more stable and accurate reference voltage, and is suitable for applications with high precision and high stability requirements.

[0065] Unless the context clearly indicates otherwise, the singular form of the words used herein and in the appended claims includes the plural and vice versa. Thus, when referring to the singular, the plural form of the corresponding term is generally included. Similarly, the words "comprise" and "include" are to be interpreted as inclusive rather than exclusive. Likewise, the terms "include" and "or" should be interpreted as inclusive unless such interpretation is expressly prohibited herein. Where the term "example" is used herein, particularly when it is located after a group of terms, the "example" is merely exemplary and illustrative and should not be considered exclusive or comprehensive.

[0066] Further aspects and scopes of adaptability become apparent from the description provided herein. It should be understood that various aspects of the present application can be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific embodiments herein are intended for purposes of illustration only and are not intended to limit the scope of the present application.

[0067] Several embodiments of the present disclosure are described in detail above, but it is obvious that those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. The protection scope of the present disclosure is defined by the attached claims.

Claims

1. A multi-level curvature compensated bandgap reference voltage circuit, comprising: A first-order temperature compensation circuit and a high-order curvature compensation circuit, characterized in that the first-order temperature compensation circuit is separated and decoupled from the high-order curvature compensation circuit, the high-order curvature compensation circuit is composed of a cascade of multiple VBE nonlinear compensation circuits, the first-order temperature compensation circuit is configured to compensate for the linear relationship between VBE and temperature changes, and the high-order curvature compensation circuit is configured to compensate for the nonlinear relationship between VBE and temperature changes.

2. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 1, characterized in that: The first-order temperature compensation circuit includes: a first operational amplifier, a first PMOS transistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a first PNP tube and a second PNP tube; one end of the fourth resistor is connected to the drain of the first PMOS transistor, and the other end is respectively connected to the second resistor and the third resistor; the output end of the first operational amplifier is connected to the gate of the first PMOS transistor, the first input end of the first operational amplifier is connected to the common connection end of the first resistor and the third resistor, and the second input end of the first operational amplifier is connected to the common connection end of the second resistor and the first PNP tube; one end of the first resistor is connected to the third resistor, and the other end is connected to the emitter of the second PNP tube; one end of the second resistor is connected to the common connection end of the third resistor and the fourth resistor, and the other end is connected to the emitter of the first PNP tube; the base of the first PNP tube is connected to the base of the second PNP tube; the base and collector of the first PNP tube and the second PNP tube are grounded.

3. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 2, characterized in that: The first operational amplifier and the first PMOS transistor form negative feedback, so that the voltage of the first input terminal of the first operational amplifier is equal to the voltage of the second input terminal. The resistance value of the fourth resistor is adjustable, and first-order temperature compensation is achieved by adjusting the resistance value of the fourth resistor.

4. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 2, characterized in that: The size ratio of the first PNP tube to the second PNP tube is 1:n, where n is an integer greater than 1.

5. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 1, characterized in that: The VBE nonlinear compensation circuit includes: a second operational amplifier, an NMOS transistor, a second PMOS transistor, a third PNP transistor, a fourth PNP transistor, a PTAT current source, a compensation current source and a bias current source; the PTAT current source is connected to the emitter of the third PNP transistor and is used to provide a bias current for the third PNP transistor; the compensation current source is respectively connected to the drain of the NMOS transistor and the gate of the second PMOS transistor and is used to provide a bias current for the fourth PNP transistor; the source of the NMOS transistor is connected to the emitter of the fourth PNP transistor, the drain of the second PMOS transistor is connected to the bias current source, and the other end of the bias current source is grounded; the first input end of the second operational amplifier is connected to the emitter of the third PNP transistor, the second input end of the second operational amplifier is connected to the emitter of the fourth PNP transistor, and the output end of the second operational amplifier is connected to the gate of the NMOS transistor; the collectors of the third PNP transistor and the fourth PNP transistor are grounded.

6. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 5, characterized in that: The second operational amplifier and the NMOS transistor form a first negative feedback, so that the emitter voltages of the third PNP tube and the fourth PNP tube are equal; the NMOS transistor, the fourth PNP tube, the PTAT current source, the second PMOS transistor and the bias current source form a second negative feedback, so that the base of the fourth PNP tube serves as a voltage output terminal.

7. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 5, characterized in that: The temperature characteristic of the compensation current source is a zero temperature coefficient or a negative temperature coefficient. At a reference temperature, the currents generated by the PTAT current source and the compensation current source are equal. High-order curvature compensation is achieved by adjusting the temperature characteristic of the compensation current and the cascade number of the VBE nonlinear compensation circuit.

8. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 5, characterized in that: The nonlinear compensation amount of the VBE nonlinear compensation circuit at each level is: Among them, VBE(Qa)-VBE(Qb) is the base-emitter voltage difference between the third PNP tube and the fourth PNP tube, Tr is the reference temperature, K is the Boltzmann constant, q is the electron charge value constant, T is the absolute temperature, and γ is the temperature characteristic of the compensation current source.

9. The multi-stage curvature compensated bandgap reference voltage circuit according to claim 8, characterized in that: Through multi-stage cascading, the output voltage of the bandgap reference voltage source is: Wherein, Vg0 is a constant independent of temperature, Tr is the reference temperature, K is the Boltzmann constant, q is the electron charge value constant, T is the absolute temperature, γ is the temperature characteristic of the compensation current source, XTI is a process-related parameter, m is the cascade number of the VBE nonlinear compensation circuit, VBE is the voltage drop between the base and the emitter, and ΔVBE is the base-emitter voltage difference between the first PNP tube and the second PNP tube.

10. A chip, characterized in that: A bandgap reference voltage circuit comprising the multi-stage curvature compensation according to any one of claims 1-9.

Images