Curvature compensation circuit and bandgap reference voltage source comprising the same

Abstract

The application discloses a curvature compensation circuit and a band gap reference voltage source comprising the same. The curvature compensation circuit according to the embodiment of the application comprises a mirror module; a first base current is provided to the mirror module via a base of a first bipolar transistor, and the mirror module generates a first mirror current according to the first base current mirroring; a second base current is provided to the mirror module via a base of a second bipolar transistor, and the mirror module generates a second mirror current according to the second base current mirroring, the area of the first bipolar transistor is the same as the area of the second bipolar transistor; the current value of the first base current is the same as the current value of the second base current; the first mirror current is used for curvature compensation; and the first mirror current and the second mirror current are used for compensating the second base current. The curvature compensation circuit and the band gap reference voltage source comprising the same according to the embodiment of the application reduce the temperature coefficient of the band gap reference voltage source and improve the precision of the band gap reference voltage source.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit technology, and in particular to a curvature compensation circuit and a bandgap reference voltage source including the same. Background Technology

[0002] Bandgap voltage references are widely used in power management chips, mixed-signal circuits, and sensor chips to provide high-precision voltage signals. Bandgap voltage references play a crucial role in the integrated circuit field. The temperature coefficient is a core indicator of a bandgap voltage reference; the smaller the change in output voltage with temperature, the lower the temperature coefficient.

[0003] The basic principle of achieving a low-temperature-coefficient bandgap reference voltage source is to generate a voltage with an approximate zero temperature coefficient by superimposing a voltage with a negative temperature coefficient and a voltage with a positive temperature coefficient. However, both the voltage and temperature coefficient at room temperature deviate from their ideal values ​​due to variations in the manufacturing process. Deviations proportional to absolute temperature can be corrected using room temperature adjustment, but deviations not proportional to absolute temperature cannot be corrected by adjustment alone. In existing technologies, deviations not proportional to absolute temperature are difficult to correct, and the actual measured temperature coefficient rarely reaches the level of the simulation.

[0004] Therefore, it is desirable to have a new curvature compensation circuit and a bandgap reference voltage source including it, which can overcome the above problems. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide a curvature compensation circuit and a bandgap reference voltage source including the same (a current-mode bandgap reference voltage source with curvature compensation), thereby reducing the temperature coefficient of the bandgap reference voltage source and improving the accuracy of the bandgap reference voltage source.

[0006] According to one aspect of the present invention, a curvature compensation circuit is provided, comprising: a mirror module; a first bipolar transistor connected to the mirror module; a first base current provided to the mirror module via the base of the first bipolar transistor, the mirror module generating a first mirror current based on the mirrored first base current; a second bipolar transistor connected to the mirror module; a second base current provided to the mirror module via the base of the second bipolar transistor, the mirror module generating a second mirror current based on the mirrored second base current, wherein the area of ​​the first bipolar transistor is the same as the area of ​​the second bipolar transistor; the current value of the first base current is the same as the current value of the second base current; the first mirror current is used for curvature compensation; the first mirror current and the second mirror current are used to compensate the second base current.

[0007] Optionally, the curvature compensation circuit further includes:

[0008] A current generation module is used to generate an initial current that is proportional to the absolute temperature.

[0009] The second resistor has its first end connected to the current generation module to receive the initial current, and its second end connected to the mirror module to receive the first mirror current.

[0010] A first resistor, the first end of which is connected to the second end of a second resistor, and the second end of the first resistor is connected to the mirror module to receive the second mirror current.

[0011] The curvature compensation circuit further includes:

[0012] The voltage output terminal is obtained based on the base-emitter voltage of the second bipolar transistor, the initial current, the first resistor and the second resistor, and the first mirror current and the first resistor.

[0013] Optionally, the current generation module includes:

[0014] Start-up circuit unit;

[0015] A current mirror unit, comprising a first current mirror unit and a second current mirror unit; the current ratio of the first current mirror unit and the second current mirror unit is 1:1;

[0016] The first transistor is connected to the first current mirror unit;

[0017] The second transistor is connected to the second current mirror unit.

[0018] Wherein, the area ratio of the first transistor to the second transistor is 1:N;

[0019] At least a portion of the startup circuit unit is mirrored with the second current mirror unit.

[0020] Optionally, the current generation module includes a first output terminal and a second output terminal;

[0021] The curvature compensation circuit also includes:

[0022] A first receiving end, the first receiving end includes a transistor Mp1 connected to the first output end and a transistor Mp2 connected to the second output end;

[0023] The second receiving terminal includes transistor Mp9 connected to the first output terminal and transistor Mp10 connected to the second output terminal.

[0024] The initial current is mirrored to the first receiving terminal and the second receiving terminal via the first output terminal and the second output terminal.

[0025] Optionally, the curvature compensation circuit further includes:

[0026] An adjustment unit is used to adjust the resistance value of the first resistor and / or the second resistor.

[0027] Optionally, the mirror module includes transistors Mp3, Mp4, Mp5, Mp6, Mp7, and Mp8;

[0028] The transistors Mp3 and Mp4 mirror the first base current and the second base current through the transistors Mp5, Mp6, Mp7 and Mp8 to obtain the first mirror current proportional to the first base current and the second mirror current proportional to the second base current, respectively.

[0029] Optionally, the first terminal of transistor Mp3 is connected to the first terminal of transistor Mp5; the third terminal of transistor Mp3 is connected to the second terminal of transistor Mp4.

[0030] The first terminal of transistor Mp4 is connected to the first terminal of transistor Mp6, and the third terminal of transistor Mp4 is connected to the first bipolar transistor.

[0031] The third terminal of transistor Mp5 is connected to the second terminal of transistor Mp6;

[0032] The third terminal of transistor Mp6 is connected to the second bipolar transistor, and the third terminal of transistor Mp6 is used to provide the second mirror current;

[0033] The first terminal of transistor Mp7 is connected to the first terminal of transistor Mp3, and the third terminal of transistor Mp7 is connected to the second terminal of transistor Mp8.

[0034] The first terminal of transistor Mp8 is connected to the first terminal of transistor Mp4, and the third terminal of transistor Mp8 is connected to the second bipolar transistor via a first resistor; the third terminal of transistor Mp8 is used to provide the first mirror current.

[0035] Optionally, the third terminal of the first bipolar transistor is connected to the third terminal of the second bipolar transistor;

[0036] The first and second terminals of the second bipolar transistor are respectively connected to the second terminal of the first resistor;

[0037] The second end of the second resistor is connected to the first end of the first resistor, and the first end of the second resistor is connected to the voltage output terminal of the curvature compensation circuit.

[0038] Optionally, a first voltage for curvature compensation is obtained based on the first mirror current and the first resistor;

[0039] A second voltage for curvature compensation is obtained based on an initial current proportional to absolute temperature, the first resistor, and the second resistor.

[0040] According to another aspect of the present invention, a bandgap reference voltage source is provided, the bandgap reference voltage source including the curvature compensation circuit as described above.

[0041] The curvature compensation circuit and the bandgap reference voltage source including the present invention utilize the nonlinearity of the bipolar current gain β to compensate for the high-order nonlinearity of VBE, utilize the bipolar transistor base current compensation technology to solve the VBE error caused by β, eliminate the error caused by β, reduce the temperature coefficient of the bandgap reference voltage source, and improve the accuracy of the bandgap reference voltage source.

[0042] Furthermore, the first mirror current is used for curvature compensation; the first mirror current and the second mirror current are used to compensate for the second base current, resulting in a simple and stable circuit structure.

[0043] Furthermore, by generating a positive temperature coefficient term through the current generation module, the entire circuit (bandgap reference voltage source) does not require the use of operational amplifiers, thus avoiding the effects of operational amplifier offset.

[0044] Furthermore, by adjusting the resistance values ​​of the first resistor and / or the second resistor, different curvature compensation requirements can be met, resulting in a wide range of applications.

[0045] Furthermore, this application utilizes bipolar transistors, resistors, and transistors, resulting in a simple circuit structure and low cost. Attached Figure Description

[0046] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0047] Figure 1 A schematic diagram of the circuit structure of a current generation module according to an embodiment of the present invention is shown.

[0048] Figure 2 A schematic diagram of the curvature compensation circuit according to an embodiment of the present invention is shown.

[0049] Figure 3 A schematic diagram illustrating the compensation effect according to an embodiment of the present invention is shown.

[0050] Figure 4 A schematic diagram comparing the temperature coefficients before and after compensation according to an embodiment of the present invention is shown. Detailed Implementation

[0051] Various embodiments of the invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale. Furthermore, certain well-known parts may not be shown in the drawings.

[0052] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. Many specific details of the invention, such as the structure, materials, dimensions, processing techniques, and methods of the components, are described below to provide a clearer understanding of the invention. However, as those skilled in the art will understand, the invention may be implemented without following these specific details.

[0053] It should be understood that when describing the structure of a component, when referring to a layer or region as being "above" or "on top of" another layer or region, it can mean that it is directly above the other layer or region, or that it contains other layers or regions between it and the other layer or region. Furthermore, if the component is flipped over, that layer or region will be located "below" or "under" the other layer or region.

[0054] Existing bandgap reference voltage sources use the sum of voltages with positive and negative temperature coefficients to obtain a voltage with a low temperature coefficient. The inventors discovered that deviations proportional to absolute temperature (PTAT) can be corrected by single-room temperature adjustment, but deviations not proportional to absolute temperature (non-PTAT) cannot be corrected by adjustment. In non-PTAT errors, V... BE Errors caused by higher-order nonlinearity and errors arising from variations in the current gain β of bipolar junction transistors (BJTs) due to process variations are issues that urgently need to be addressed.

[0055] To address the aforementioned problems, the inventors proposed a novel curvature compensation circuit. This curvature compensation circuit includes a mirror module, a first bipolar transistor, and a second bipolar transistor.

[0056] Specifically, the first bipolar transistor is connected to the mirror module. A first base current is provided to the mirror module via the base of the first bipolar transistor, and the mirror module generates a first mirror current based on the first base current.

[0057] The second bipolar transistor is connected to the mirror module. The second base current is supplied to the mirror module via the base of the second bipolar transistor, and the mirror module generates a second mirror current based on the second base current.

[0058] The area of ​​the first bipolar transistor is the same as that of the second bipolar transistor; the current value of the first base current is the same as that of the second base current. The first mirror current is used for curvature compensation, and the first and second mirror currents are used to compensate for the second base current.

[0059] Optionally, the curvature compensation circuit further includes a current generation module, a second resistor, a first resistor, and a voltage output terminal. The current generation module generates an initial current proportional to the absolute temperature. The first terminal of the second resistor is connected to the current generation module to receive the initial current, and the second terminal of the second resistor is connected to a mirror module to receive a first mirror current. The first terminal of the first resistor is connected to the second terminal of the second resistor, and the second terminal of the first resistor is connected to the mirror module to receive a second mirror current. The voltage output terminal is obtained based on the base-emitter voltage of the second bipolar transistor, the initial current, the first and second resistors, and the first mirror current and the first resistor.

[0060] According to the curvature compensation circuit of the above embodiment of the present invention, the nonlinearity of the bipolar current gain β is used to compensate for V. BE The higher-order nonlinearity is addressed by using bipolar transistor base current compensation technology to solve the V caused by β. BE The error caused by β is eliminated, the temperature coefficient of the bandgap reference voltage source is reduced, and the accuracy of the bandgap reference voltage source is improved; the first resistor and the first mirror current are set to achieve curvature compensation; the nonlinearity of the bipolar transistor current gain β is used to compensate for V. BE In higher-order nonlinearities, only the second bipolar transistor is involved.

[0061] Figure 1 A schematic diagram of the circuit structure of a current generation module according to an embodiment of the present invention is shown. Figure 1 As shown, in one specific embodiment, the current generation module includes a startup circuit unit, a current mirror unit, a first transistor Q3, and a second transistor Q4. Figure 1 It is a PTAT current generating circuit. Figure 1 In this circuit, AVSS (Analog VSS) represents the ground of the analog section, AVDD represents the power supply (for the analog circuit), Mp represents a P-type transistor, Mn represents an N-type transistor, Q represents a bipolar transistor, and R represents a resistor. Of course, the current generation module is not limited to the specific structure described below and can also have other structures.

[0062] Specifically, the current mirror unit includes a first current mirror unit and a second current mirror unit, and the current ratio of the first current mirror unit and the second current mirror unit is 1:1.

[0063] The first transistor Q3 is connected to the first current mirror unit; the second transistor Q4 is connected to the second current mirror unit. The area ratio of the first transistor Q3 to the second transistor Q4 is 1:N.

[0064] At least a portion of the startup circuit unit is mirrored with the second current mirror unit.

[0065] Optionally, the current generation module further includes a first output terminal vbp and a second output terminal vbpc. The first receiving terminal of the curvature compensation circuit is connected to both the first output terminal vbp and the second output terminal vbpc. The first receiving terminal includes transistor Mp1 connected to the first output terminal vbp and transistor Mp2 connected to the second output terminal vbpc (see Appendix). Figure 2 The second receiving terminal of the curvature compensation circuit is connected to the first output terminal vbp and the second output terminal vbpc, respectively. The second receiving terminal includes transistor Mp9 connected to the first output terminal vbp and transistor Mp10 connected to the second output terminal vbpc (see appendix). Figure 2 The initial current is mirrored to the first and second receiving terminals via the first and second output terminals. Optionally, the curvature compensation circuit further includes an adjustment unit for adjusting the resistance values ​​of the first and / or second resistors.

[0066] Figure 2 A schematic diagram of the curvature compensation circuit according to an embodiment of the present invention is shown. Figure 2 As shown, in one specific embodiment, the curvature compensation circuit includes transistors Mp3, Mp4, Mp5, Mp6, Mp7, and Mp8, etc. Figure 2 In this circuit, AVSS represents the ground of the analog section, AVDD represents the power supply (for the analog circuit), Mp represents a p-type transistor, Mn represents an N-type transistor, Q represents a bipolar transistor, and R represents a resistor. Of course, the curvature compensation circuit is not limited to the specific structure described below and can also have other structures.

[0067] Specifically, transistors Mp3 and Mp4 mirror the first base current and the second base current through transistors Mp5, Mp6, Mp7 and Mp8 to obtain a first mirror current proportional to the first base current and a second mirror current proportional to the second base current, respectively.

[0068] Optionally, the first terminal of transistor Mp3 is connected to the first terminal of transistor Mp5; the third terminal of transistor Mp3 is connected to the second terminal of transistor Mp4. The first terminal of transistor Mp4 is connected to the first terminal of transistor Mp6, and the third terminal of transistor Mp4 is connected to the first bipolar transistor. The third terminal of transistor Mp5 is connected to the second terminal of transistor Mp6. The third terminal of transistor Mp6 is connected to the second bipolar transistor, and the third terminal of transistor Mp6 is used to provide a second mirror current. The first terminal of transistor Mp7 is connected to the first terminal of transistor Mp3, and the third terminal of transistor Mp7 is connected to the second terminal of transistor Mp8. The first terminal of transistor Mp8 is connected to the first terminal of transistor Mp4, and the third terminal of transistor Mp8 is connected to the second bipolar transistor via a first resistor R1. The third terminal of transistor Mp8 is used to provide a first mirror current.

[0069] Optionally, the third terminal of the first bipolar transistor Q1 is connected to the third terminal of the second bipolar transistor Q2. The first and second terminals of the second bipolar transistor Q2 are respectively connected to the second terminal of the first resistor R1. The second terminal of the second resistor R2 is connected to the first terminal of the first resistor R1, and the first terminal of the second resistor R2 is connected to the voltage output terminal (of the curvature compensation circuit).

[0070] Optionally, a first voltage for curvature compensation is obtained based on a first mirror current and a first resistor R1. A second voltage for curvature compensation is obtained based on an initial current proportional to absolute temperature, the first resistor R1, and a second resistor R2.

[0071] Combination Figure 1 and Figure 2 The content shown is, in a specific embodiment of the present invention, Figure 1 The current generation module shown generates a current IPTAT that is proportional to the absolute temperature, and is then... Figure 2The circuit shown undergoes curvature compensation. Transistors Mp11, Mp12, Mp13, and Mp14 in the current generation module form a current mirror with a 1:1 current ratio. The area ratio of transistors Q3 and Q4 is 1:N. Transistors Mn1, Mn2, Mn3, Mn4, Mp15, and Mp16 form the startup circuit in the current generation module. Specifically, transistors Mp15 / Mp16 and Mp13 / Mp14 are mirrored; when the current of transistors Mp13 / Mp14 is 0, a current path is generated for transistors Mp13 / Mp14 / Mn2. The current generation module generates an initial current IPTAT without curvature, proportional to absolute temperature, which constitutes the positive temperature coefficient term of the curvature compensation circuit (bandgap reference voltage source). The generated current IPTAT is mirrored through the first output terminal vbp and the second output terminal vbpc to... Figure 2 The circuit section shown.

[0072] Specifically, refer to Figure 1 As shown, let R b =R c ;

[0073] V BE1 +I B ·R C =V BE2 +(I B +IPTAT) ·R B (1)

[0074]

[0075] Among them, V BE1 The base-emitter voltage of Q1, I B For the current flowing through resistor R B current, V BE2 IPTAT is the base-emitter voltage of Q2, and IPTAT is the initial current.

[0076] As can be seen from the above formula (2), the generated initial current IPTAT is a PTAT term that does not contain curvature.

[0077] Reference Figure 2As shown, the first receiving terminal (transistor Mp1 / transistor Mp2) and the second receiving terminal (transistor Mp9 / transistor Mp10) are connected to the first output terminal vbp and the second output terminal vbpc of the current generation module to obtain the initial current IPTAT. The area ratio of transistor Q1 (first bipolar transistor) to transistor Q2 (second bipolar transistor) is 1:1, and the base current flowing through the two transistors is the same. Transistors Mn1 / Mp3 / Mp4 mirror the base current of Q1 / Q2 through transistors Mp5 / Mp6 / Mp7 / Mp8 to obtain currents IB_COMP (second mirror current) and IC_COMP (first mirror current), which are proportional to the base current of Q1 / Q2, respectively. The voltage drop across resistor R1 caused by IC_COMP is used to compensate for the curvature of VBE, and the sum of IB_COMP and IC_COMP is used to compensate for the base current of Q2. The voltage output of the curvature compensation circuit is... Figure 2 The output port VBG is shown.

[0078] In the above embodiments of the present invention, the nonlinear current IC_COMP is obtained by utilizing the nonlinearity of the bipolar transistor (BJT) itself β. Figure 3 ( Figure 3 A schematic diagram illustrating the compensation effect according to an embodiment of the present invention is shown. Figure 3 It is V BE The curve compensation with an upward opening (including nonlinear terms, β-nonlinear curvature compensation terms, and the waveform after β-nonlinear compensation) is shown. Figure 3 The curve V shown opens downwards. BE The higher-order nonlinearity ultimately yields the bandgap reference voltage V. BG for:

[0079] V BG =V BE2 +IPTAT(R1+R2)+IC_COMP·R1 (3)

[0080] Among them, V BE2 For the base-emitter voltage of Q2, IC_COMP·R1 is the introduced curvature compensation term (generated using the nonlinearity of the BJT current gain β, see formulas (6) and (7) below). Figure 3 The upward-opening curve shown is used to compensate for formula V. BE Formula (9) included Figure 3 The aforementioned higher-order nonlinearity with the opening facing downwards.

[0081] The expression for current gain β in relation to temperature is:

[0082]

[0083] Where β(T) is non-PTAT, and I is obtained from this. B It is also non-PTAT, for I B Taylor expansion yields:

[0084]

[0085]

[0086]

[0087] Where α is the current multiple of the current mirror. Plotting IC_COMP·R1 yields... Figure 3 The waveform shown has an upward opening.

[0088] V for Q2 BE Curvature analysis using higher-order nonlinearity yields the following results:

[0089]

[0090] Among them, V BG This is the bandgap reference voltage at -273℃, where Tr is the selected reference temperature, and δ is a process-dependent constant. (δ-1) This is the source of temperature nonlinearity, and can be expressed as:

[0091]

[0092] (9)

[0094] like Figure 3 As shown, plotting the above nonlinear terms yields a downward-opening curve, which can be compensated for by the upward-opening curve IC_COMP·R1. Therefore, for V BE Higher-order nonlinearities can be obtained by introducing a nonlinearity of β and superimposing it. Figure 3 The curve shown represents a lower temperature coefficient, achieving the goal of reducing the temperature coefficient of the bandgap reference voltage source. According to... Figure 3 It can be seen that the high-order nonlinearity of the downward curve VBE is compensated by utilizing the nonlinearity of β of the BJT itself; and the base current compensation technology is used to make VBE1 unaffected by the change of β.

[0095] The above describes the nonlinear compensation of V using the BJT's own β. BE Higher-order nonlinearity. In addition, the use of BJT base current compensation technology can also address the V variation caused by differences in β due to process variations. BE error.

[0096] For existing bandgap reference voltage sources, the emitter and collector currents are different, and the deviation of β in the BJT will cause V BE This produces a non-PTAT change.

[0097] Unlike existing bandgap reference voltage sources, the technical solution of this application utilizes IB_COMP (second mirror current) and IC_COMP (first mirror current) to compensate for the base current of Q2, making...

[0098] IB_COMP+IC_COMP=I B2 (10)

[0099] Among them, I B2 Let be the base current of Q2. Since the currents through the collector and emitter of Q2 are the same, we get:

[0100]

[0101] Unlike traditional bandgap source sources, the V obtained according to the scheme of this application BE2 The temperature-dependent β is eliminated by the base current compensation of the BJT, thus eliminating the non-PTAT error caused by the BJT current gain β.

[0102] In the technical solution claimed in this application, the low temperature coefficient bandgap reference voltage source of the present invention is designed using CMOS technology, for example, using... Figure 1 and Figure 2 The proposed scheme involves adjusting the ratio of resistors R1 and R2 to make the absolute values ​​of the slopes of the positive and negative temperature coefficient terms the same. Temperature scans from -40℃ to 120℃ are then performed on a reference source without compensation technology, a reference source with BJT base current compensation technology, and a reference source using both of the aforementioned compensation technologies, comparing their temperature coefficients. Disconnecting the IB_COMP and IC_COMP currents results in a reference source without compensation. Disconnecting the IC_COMP current, making IB_COMP equal to the BJT base current, results in a reference source using only BJT base current compensation technology. The IB_COMP and IC_COMP currents are then... Figure 2 As shown, the reference source is connected, and the nonlinearity of the BJTβ is used to compensate for the nonlinearity of VBE itself, and the BJT base current compensation technology is adopted.

[0103] Figure 4 A schematic diagram comparing the temperature coefficients before and after compensation according to an embodiment of the present invention is shown, illustrating a comparison of the temperature coefficients of the three bandgap reference voltage sources described above.

[0104] The temperature coefficient of the reference source without compensation technology is 21 μV / ℃, serving as a control. The temperature coefficient of the bandgap reference voltage source using only BJT base current compensation technology is 16 μV / ℃, a reduction of 24%. The temperature coefficient of the bandgap reference voltage source utilizing the nonlinearity of BJTβ and employing BJT base current compensation technology is 8 μV / ℃, a reduction of 62%. Simulation results show that the two curvature compensation techniques used in this application can significantly reduce the temperature coefficient of the bandgap reference voltage source and improve its accuracy.

[0105] According to another aspect of the present invention, a bandgap reference voltage source is provided. This bandgap reference voltage source includes the curvature compensation circuit described above. This bandgap reference voltage source is used, for example, in power management chips, mixed-signal circuits, sensor chips, etc.

[0106] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0107] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A curvature compensation circuit, comprising: a mirror module; a first bipolar transistor connected to the mirror module; a first base current provided to the mirror module via a base of the first bipolar transistor, the mirror module generating a first mirror current according to a mirror of the first base current; a second bipolar transistor connected to the mirror module; a second base current provided to the mirror module via a base of the second bipolar transistor, the mirror module generating a second mirror current according to a mirror of the second base current, wherein an area of the first bipolar transistor is same as an area of the second bipolar transistor; a current value of the first base current is same as a current value of the second base current; the first mirror current is used for curvature compensation; the first mirror current and the second mirror current are used for compensating the second base current.

2. The curvature compensation circuit of claim 1, wherein, The curvature compensation circuit further comprises: a current generation module configured to generate an initial current proportional to absolute temperature; a second resistor, a first end of the second resistor connected to the current generation module to receive the initial current, a second end of the second resistor connected to the mirror module to receive the first mirror current; a first resistor, a first end of the first resistor connected to the second end of the second resistor, a second end of the first resistor connected to the mirror module to receive the second mirror current, wherein the curvature compensation circuit further comprises: a voltage output terminal, a voltage output by the voltage output terminal is according to a base-emitter voltage of the second bipolar transistor, the initial current, the first resistor and the second resistor, and the first mirror current and the first resistor.

3. The curvature compensation circuit of claim 2, wherein, The current generation module comprises: an enable circuit unit; a current mirror unit, the current mirror unit comprising a first current mirror sub-unit and a second current mirror sub-unit; a current ratio of the first current mirror sub-unit and the second current mirror sub-unit is 1:1; a first triode connected to the first current mirror sub-unit; a second triode connected to the second current mirror sub-unit, wherein an area ratio of the first triode and the second triode is 1:N; at least a part of the enable circuit unit is mirrored to the second current mirror sub-unit.

4. The curvature compensation circuit of claim 2, wherein, The current generation module comprises a first output terminal and a second output terminal; The curvature compensation circuit further comprises: a first receiving terminal, the first receiving terminal comprising a transistor Mp1 connected to the first output terminal and a transistor Mp2 connected to the second output terminal; a second receiving terminal, the second receiving terminal comprising a transistor Mp9 connected to the first output terminal and a transistor Mp10 connected to the second output terminal, wherein the initial current is mirrored to the first receiving terminal and the second receiving terminal via the first output terminal and the second output terminal.

5. The curvature compensation circuit of claim 2, wherein, The curvature compensation circuit further comprises: an adjusting unit configured to adjust a resistance value of the first resistor and / or the second resistor.

6. The curvature compensation circuit of claim 1, wherein, The mirror module comprises a transistor Mp3, a transistor Mp4, a transistor Mp5, a transistor Mp6, a transistor Mp7, and a transistor Mp8; The transistor Mp3 and the transistor Mp4 mirror the first base current and the second base current through the transistor Mp5, the transistor Mp6, the transistor Mp7 and the transistor Mp8 to obtain the first mirror current proportional to the first base current and the second mirror current proportional to the second base current respectively.

7. The curvature compensation circuit of claim 6, wherein, The first end of the transistor Mp3 is connected to the first end of the transistor Mp5; the third end of the transistor Mp3 is connected to the second end of the transistor Mp4; The first end of the transistor Mp4 is connected to the first end of the transistor Mp6; the third end of the transistor Mp4 is connected to the first bipolar transistor; The third end of the transistor Mp5 is connected to the second end of the transistor Mp6; The third end of the transistor Mp6 is connected to the second bipolar transistor; the third end of the transistor Mp6 is used to provide the second mirror current; The first end of the transistor Mp7 is connected to the first end of the transistor Mp3; the third end of the transistor Mp7 is connected to the second end of the transistor Mp8; The first end of the transistor Mp8 is connected to the first end of the transistor Mp4; the third end of the transistor Mp8 is connected to the second bipolar transistor through a first resistor; the third end of the transistor Mp8 is used to provide the first mirror current.

8. The curvature compensation circuit of claim 2, wherein, The third end of the first bipolar transistor is connected to the third end of the second bipolar transistor; The first end and the second end of the second bipolar transistor are connected to the second end of the first resistor respectively; The second end of the second resistor is connected to the first end of the first resistor; the first end of the second resistor is connected to the voltage output end of the curvature compensation circuit.

9. The curvature compensation circuit of claim 8, wherein, A first voltage for curvature compensation is obtained according to the first mirror current and the first resistor; A second voltage for curvature compensation is obtained according to an initial current proportional to absolute temperature, the first resistor and the second resistor.

10. A bandgap reference voltage source, comprising: The curvature compensation circuit according to any one of claims 1-9.

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