Band-gap reference circuit

Abstract

The invention discloses a band-gap reference circuit which comprises a band-gap reference core module used for superposing a positive temperature coefficient voltage and a negative temperature coefficient voltage to generate a band-gap reference voltage; and the reference output module is used for dividing the band-gap reference voltage to generate a reference voltage. Wherein the band-gap reference core module comprises a temperature excursion trimming unit, the temperature excursion trimming unit is used for trimming the temperature excursion of the band-gap reference voltage by adjusting the positive temperature coefficient voltage, and the reference output module further comprises a temperature excursion compensation unit used for adjusting the voltage division proportion of the reference output module. Therefore, the offset generated in the reference voltage in the temperature drift trimming process is eliminated. According to the band-gap reference circuit, it can be guaranteed that the reference voltage is not affected by the temperature condition, the consistency of the reference voltage can be guaranteed, and the application requirement is well met.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and more particularly to a bandgap reference circuit. Background Art

[0002] In integrated circuits, the bandgap voltage reference (Bandgap for short) circuit is an indispensable unit module, which provides the circuit with a high-precision, high-stability reference voltage that basically does not change with the device process, temperature and power supply voltage. It is widely used in high-performance analog, mixed analog and digital, digital and power management systems and other chip circuits. Its accuracy and stability directly affect the accuracy of the entire system. The principle is to add a voltage with a negative temperature coefficient and a voltage with a positive temperature coefficient with appropriate weights to obtain a zero temperature coefficient voltage.

[0003] The conventional bandgap reference circuit is The positive temperature coefficient voltage generated is related to the base-emitter PN junction voltage of the bipolar transistor (BJT). The negative temperature coefficient voltages generated offset each other to achieve a zero temperature coefficient bandgap reference voltage. Conventional bandgap reference circuits such as Figure 1 As shown, the number of bipolar transistors Q1 and Q2 is different, which produces , and then through the operational amplifier AMP clamping the voltage of the positive and negative input terminals and the mirror current of the NMOS transistors N1~N3 of the same size, the reference voltage V with zero temperature coefficient can be finally obtained. REF . However, in practical applications, since the internal devices are still affected by the process angle during manufacturing, the resulting temperature drift may still be large, and this effect cannot be eliminated by high-order compensation technology. Therefore, it is necessary to add corresponding adjustment technology to adjust the positive temperature coefficient current and resistance under different process angles, which is of great significance for improving the accuracy of the bandgap reference voltage and reducing the output voltage temperature drift.

[0004] like Figure 1 As shown, in the conventional bandgap reference circuit 100, the output reference voltage V is adjusted by adjusting the absolute value of the resistor Rt. REF However, if Figure 2 As shown, the reference voltage V after adjusting the temperature coefficient in this way REF The voltage value at room temperature will deviate from the design value, which will directly affect the application of the subsequent system. Summary of the invention

[0005] In view of the above problems, the object of the present invention is to provide a bandgap reference circuit, which can not only ensure that the reference voltage is not affected by temperature conditions, but also ensure the consistency of the reference voltage, thereby better meeting application requirements.

[0006] According to one aspect of the present invention, a bandgap reference circuit is provided, comprising: a bandgap reference core module, used to generate a positive temperature coefficient voltage and a negative temperature coefficient voltage, and superimpose the positive temperature coefficient voltage and the negative temperature coefficient voltage to generate a bandgap reference voltage; a reference output module, used to divide the bandgap reference voltage to generate a reference reference voltage, wherein the bandgap reference core module comprises a temperature drift adjustment unit, the temperature drift adjustment unit is used to adjust its own first resistance value according to a first adjustment control signal to adjust the positive temperature coefficient voltage, thereby achieving temperature drift adjustment of the bandgap reference voltage, the reference output module also comprises a temperature drift compensation unit, used to adjust its own second resistance value according to the first adjustment control signal to adjust the voltage division ratio of the reference output module, thereby eliminating the offset generated in the reference reference voltage during the temperature drift adjustment process, wherein the ratio of the second resistance value of the temperature drift compensation unit to the first resistance value of the temperature drift adjustment unit is fixed.

[0007] Optionally, the bandgap reference core module further includes first and second bipolar transistors, first to third transistors, first to fifth resistors and an operational amplifier, wherein a first end of the third resistor is connected to a power supply voltage, a second end of the third resistor is connected to a first end of the first transistor and an inverting input end of the operational amplifier, a control end of the first transistor is connected to a control end of the second transistor and an output end of the operational amplifier, a second end of the first transistor is connected to a collector of the first bipolar transistor, a base of the first bipolar transistor is connected to a base of the second bipolar transistor, a second end of the first bipolar transistor is connected to a first end of the first resistor, a second end of the first resistor is connected to an emitter of the second bipolar transistor and a first end of the second resistor, and a second end of the second resistor is connected to an emitter of the second bipolar transistor and a first end of the second resistor. The first end of the fourth resistor is connected to the power supply voltage, the second end of the fourth resistor is connected to the first end of the second transistor and the non-inverting input terminal of the operational amplifier, the second end of the second transistor is connected to the collector of the second bipolar transistor, the first end of the fifth resistor is connected to the power supply voltage, the second end of the fifth resistor is connected to the first end of the third transistor, the control end of the third transistor is connected to the output end of the operational amplifier, and the second end of the third transistor is connected to the collector of the second bipolar transistor, wherein the emitter junction areas of the first bipolar transistor and the second bipolar transistor are different, and the collector of the second bipolar transistor is used to output the bandgap reference voltage.

[0008] Optionally, the temperature drift trimming unit includes a plurality of first trimming resistors and a plurality of first trimming switches, the plurality of first trimming resistors are connected in series between the second end of the second resistor and ground, the plurality of first trimming switches correspond one-to-one to the plurality of first trimming resistors, and the conduction and disconnection of the plurality of first trimming switches are controlled by the first trimming control signal.

[0009] Optionally, the reference output module includes the temperature drift compensation unit, a sixth resistor and a seventh resistor, wherein the temperature drift compensation unit includes a plurality of second trimming resistors and a plurality of second trimming switches, the plurality of second trimming resistors, the sixth resistor and the seventh resistor are connected in series between the bandgap reference voltage and ground, an intermediate node between the sixth resistor and the seventh resistor is used to output the reference reference voltage, the plurality of second trimming switches correspond one-to-one to the plurality of second trimming resistors, and the conduction and disconnection of the plurality of second trimming switches are controlled by the first trimming control signal.

[0010] Optionally, the multiple second trimming resistors correspond one-to-one to the multiple first trimming resistors, and the resistance value of each second trimming resistor is k times the resistance value of the corresponding first trimming resistor, wherein k is set by the ratio between a first equivalent resistance and a second equivalent resistance, the first equivalent resistance is equal to the sum of the resistances of the second resistor and the temperature drift trimming unit, and the second equivalent resistance is equal to the equivalent resistance value of the reference output module.

[0011] Optionally, the reference output module further includes: a voltage trimming unit, configured to adjust its own third resistance value according to a second trimming control signal to adjust the voltage division ratio of the reference output module, thereby eliminating the offset voltage generated by the operational amplifier.

[0012] Optionally, the voltage trimming unit includes a plurality of third trimming resistors and a plurality of third trimming switches, the plurality of third trimming resistors are connected in series, the plurality of third trimming switches correspond one-to-one to the plurality of third trimming resistors, and the on and off of the plurality of third trimming switches are controlled by the second trimming control signal.

[0013] Optionally, resistance values ​​of the plurality of first trimming resistors, the plurality of second trimming resistors, and the plurality of third trimming resistors are respectively increased in binary weighted order.

[0014] Optionally, the first trimming control signal and the second trimming control signal respectively include a multi-bit binary code.

[0015] Optionally, the first bipolar transistor and the second bipolar transistor are NPN transistors, and the first transistor to the third transistor are NMOS transistors.

[0016] In summary, compared with the prior art, the bandgap reference circuit of the embodiment of the present invention uses a temperature drift compensation unit to synchronously offset the offset introduced by the temperature drift adjustment unit in the reference reference voltage, thereby solving the problem of voltage value deviation of the reference reference voltage at room temperature caused by the existing temperature drift adjustment, and helps to optimize the adjustment method. It can not only ensure that the reference reference voltage is not affected by temperature conditions, but also ensure the consistency of the reference reference voltage, thereby better meeting application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0018] Figure 1 A schematic circuit diagram of a conventional bandgap reference circuit is shown.

[0019] Figure 2 A schematic diagram showing a waveform of a reference voltage of a conventional bandgap reference circuit after temperature drift adjustment.

[0020] Figure 3 A schematic circuit diagram showing a bandgap reference circuit according to an embodiment of the present invention.

[0021] Figure 4 A schematic circuit diagram of a temperature drift adjustment unit according to an embodiment of the present invention is shown.

[0022] Figure 5 A schematic circuit diagram of a temperature drift compensation unit according to an embodiment of the present invention is shown.

[0023] Figure 6 A schematic circuit diagram of a voltage trimming unit according to an embodiment of the present invention is shown.

[0024] Figure 7 A schematic diagram showing a waveform of a reference voltage of a bandgap reference circuit after temperature drift adjustment according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0025] Reference will now be made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.Where possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.

[0026] In the specification, it should be noted that similar reference numerals that have been used to represent similar parts in other drawings are used for these elements as much as possible. In the following description, when functions and configurations known to those skilled in the art are not related to the basic configuration of the present disclosure, their detailed description will be omitted. The terms described in the specification should be understood as follows.

[0027] The advantages and features of the present disclosure and their implementation methods will be described through the following embodiments described with reference to the accompanying drawings. However, the present disclosure can be implemented in different forms and should not be interpreted as being limited to the embodiments described herein. Rather, these embodiments are provided to make the present disclosure comprehensive and complete, so as to fully convey the scope of the present disclosure to those skilled in the art. In addition, the present disclosure is limited only by the scope of the claims.

[0028] The shapes, sizes, ratios, angles, and quantities disclosed in the drawings used to describe the embodiments of the present disclosure are merely examples, and the present disclosure is therefore not limited to the illustrated details. Similar reference numerals always represent similar elements. In the following description, when it is determined that a detailed description of a related known function or construction will inevitably obscure the focus of the present disclosure, the detailed description will be omitted.

[0029] As those skilled in the art can fully understand, the features of the various embodiments of the present disclosure can be partially or completely combined or combined with each other, and can interoperate and technically drive each other in various ways. The embodiments of the present disclosure can be performed independently of each other, or can be performed together in a mutually dependent relationship.

[0030] In the present application, a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) includes a first end, a second end and a control end. When the MOS tube is in the on state, current flows from the first end to the second end. The first end, the second end and the control end of the PMOS tube are the source, the drain and the gate, respectively, and the first end, the second end and the control end of the NMOS tube are the drain, the source and the gate, respectively. A bipolar transistor (also known as a bipolar transistor) includes a first end, a second end and a control end. When the bipolar transistor is in the on state, current flows from the first end to the second end. The first end, the second end and the control end of the PNP tube are the emitter, the collector and the base, respectively, and the first end, the second end and the control end of the NPN tube are the collector, the emitter and the base, respectively.

[0031] Figure 3 FIG. 2 is a schematic circuit diagram of a bandgap reference circuit according to an embodiment of the present invention. Figure 3 As shown, the bandgap reference circuit 200 includes a bandgap reference core module 210 and a reference output module 220. The bandgap reference core module 210 is used to generate a positive temperature coefficient voltage and a negative temperature coefficient voltage, and superimpose the positive temperature coefficient voltage and the negative temperature coefficient voltage to generate a bandgap reference voltage V BG The reference output module 220 is used to output the bandgap reference voltage V BG Divide the voltage to generate the reference voltage V REF .

[0032] Furthermore, the bandgap reference core module 210 includes bipolar transistors Q1 and Q2 , transistors N1 to N3 , resistors R1 to R5 , an operational amplifier AMP and a temperature drift adjustment unit 201 .

[0033] Specifically, the first end of the resistor R3 is connected to the power supply voltage VCC, and the second end of the resistor R3 is connected to the first end of the transistor N1 and the first input end of the operational amplifier AMP at the node A1. The control end of the transistor N1 is connected to the control end of the transistor N2 and the output end of the operational amplifier AMP, and the second end of the transistor N1 is connected to the first end of the bipolar transistor Q1. The control end of the bipolar transistor Q1 is connected to the control end of the bipolar transistor Q2, the second end of the bipolar transistor Q1 is connected to the first end of the resistor Q1, and the second end of the resistor R1 is connected to the second end of the bipolar transistor Q2 and the first end of the resistor R2 at the node A3. The second end of the resistor R2 is connected to the first end of the temperature drift adjustment unit 201, and the second end of the temperature drift adjustment unit 201 is connected to the ground. The first end of the resistor R4 is connected to the power supply voltage VCC, and the second end of the resistor R4 is connected to the first end of the transistor N2 and the second input end of the operational amplifier AMP at the node A2. The second end of the transistor N2 is connected to the first end and the control end of the bipolar transistor Q2, and the second end of the bipolar transistor Q2 is connected to the node A3. The first end of the resistor R5 is connected to the power supply voltage VCC, the second end of the resistor R5 is connected to the first end of the transistor N3, the control end of the transistor N3 is connected to the output end of the operational amplifier AMP, and the second end of the transistor N3 is connected to the first end of the bipolar transistor Q2. The first end of the bipolar transistor Q2 is used to output the bandgap reference voltage V BG .

[0034] In this embodiment, the resistance values ​​of resistors R3 and R4 are the same, the resistance values ​​of resistors R1 and R2 are not equal, and the emitter area ratio of the bipolar transistor Q1 to the bipolar transistor Q2 is 1:N, where N is an integer greater than 1. As an example, N is set to 8.

[0035] More specifically, in this embodiment, the transistors N1 to N3 are NMOS transistors, and accordingly, the first terminals of the transistors N1 to N3 are drains, the second terminals are sources, and the control terminals are gates. It can be understood that in actual use, the device types of the transistors N1 to N3 can be configured as needed, and any device that can implement current mirroring so that the current I1 flowing through the transistor N1 is equal to the current I2 flowing through the transistor N2 is applicable to the present invention, and is not limited to this embodiment.

[0036] More specifically, in this embodiment, the inverting input terminal of the operational amplifier AMP is used as the first input terminal, and the non-inverting input terminal is used as the second input terminal. In actual use, the corresponding relationship between the input polarity and the input signal can be set as needed, and the voltages of the two input terminals of the operational amplifier AMP can be equal based on the "virtual short" principle of the operational amplifier, which is not limited to this embodiment.

[0037] More specifically, in this embodiment, the bipolar transistors Q1 and Q2 are implemented by NPN transistors, and accordingly, the first end of the bipolar transistors Q1 and Q2 is the collector, the second end is the emitter, and the control end is the base. In actual use, any device and structure that can realize temperature sensing based on PN junction is applicable to the present invention, including but not limited to PNP transistors (Bipolar Junction Transistor), NMOS tubes or PMOS tubes (Metal Oxide Semiconductor Field Effect Transistor), which are not described one by one here.

[0038] Furthermore, the reference output module 220 includes a temperature drift compensation unit 202, a voltage trimming unit 203, and resistors R6 and R7. The temperature drift compensation unit 202, the voltage trimming unit 203, the resistor R6 and the resistor R7 are connected in series to the bandgap reference voltage V BG and ground, the middle node between resistor R6 and resistor R7 is used to output the reference voltage V REF .

[0039] In this embodiment, the temperature drift trimming unit 201 is used to adjust its own resistance value Rt according to the first trimming control signal Trim1 to adjust the voltage value of the positive temperature coefficient voltage generated by the bandgap reference core module 210, thereby achieving the bandgap reference voltage V BG The temperature drift of the bandgap reference voltage V BG After temperature drift adjustment, the reference voltage V REF Under normal temperature conditions, the temperature drift compensation unit 202 deviates from the design value. Therefore, the technical solution of this embodiment also includes adjusting its own resistance value Rs according to the first trimming control signal Trim1 through the temperature drift compensation unit 202, thereby adjusting the voltage division ratio of the reference output module to eliminate the temperature drift during the temperature drift trimming process. REF Furthermore, the ratio of the equivalent resistance value Rs of the temperature drift compensation unit 202 to the equivalent resistance value Rt of the temperature drift adjustment unit 201 is fixed, wherein the fixed means that when the first adjustment control signal Trim1 changes, the resistance value Rs of the temperature drift compensation unit 202 and the resistance value Rt of the temperature drift adjustment unit 201 may change, but the ratio between the two remains unchanged.

[0040] Based on the above structural analysis, it can be seen that due to the "virtual short" characteristic of the operational amplifier AMP, the voltages of the non-inverting input terminal and the inverting input terminal of the operational amplifier AMP are equal (that is, V A1 =V A2), and since the transistor N1 and the transistor N2 have the same gate-source voltage, the current flowing through the transistor N1 is equal to the current flowing through the transistor N2, that is, The base-emitter voltage of the bipolar transistor Q2 is The difference between the base-emitter voltage of the bipolar transistor Q1 and the base-emitter voltage of the bipolar transistor Q2 is inversely proportional to the absolute temperature (CTAT). Proportional to absolute temperature (PTAT). Therefore, a current with a positive temperature coefficient is generated in the branch where the bipolar transistor Q1 is located and the branch where the bipolar transistor Q2 is located, that is, , from which we can get the emitter voltage of bipolar transistor Q2 , where Rt is the equivalent resistance value of the temperature drift adjustment unit 201. For the bipolar transistor Q2, its collector voltage VB is equal to the bandgap reference voltage V BG , and because , so we can get the bandgap reference voltage V BG The expression is:

[0041] (1)

[0042] According to formula (1), the bandgap reference voltage V can be adjusted by adjusting the resistance value of the temperature drift adjustment unit 201: BG The temperature drift coefficient is calculated to obtain a bandgap reference voltage with low temperature drift.

[0043] Based on the above analysis, compensation is further performed based on the temperature drift compensation unit 202, which adjusts the voltage division ratio of the reference output module 220 to eliminate the reference voltage V REF The offset generated in the final reference voltage V REF The expression is:

[0044] (2)

[0045] According to formula (2), the bandgap reference circuit 200 of the embodiment of the present invention can adjust the resistance ratio k between the temperature drift compensation unit 202 and the temperature drift adjustment unit 201 to make the reference voltage V REF With design value equal, thus ensuring that the reference voltage V after temperature drift adjustment REF No offset will occur.

[0046] Furthermore, due to the influence of the offset voltage of the operational amplifier AMP itself, the reference voltage V REFA certain offset will still occur, so the bandgap reference circuit 200 of the embodiment of the present invention further includes a voltage trimming unit 203 disposed in the reference output module 220. The voltage trimming unit 203 is used to adjust its own resistance value Rf according to the second trimming control signal Trim2, thereby eliminating the offset voltage of the operational amplifier AMP itself to the reference reference voltage V REF The resulting offset.

[0047] Figure 4 FIG. 2 is a schematic circuit diagram of a temperature drift adjustment unit according to an embodiment of the present invention. Figure 4 As shown, the temperature drift trimming unit 201 includes a plurality of first trimming resistors Rt_1~Rt_n and a plurality of first trimming switches S1_1~S1_n, where n is an integer greater than 1. The plurality of first trimming resistors Rt_1~Rt_n are connected in series between the second end of the resistor R2 and the ground, and the plurality of first trimming switches S1_1~S1_n correspond to the plurality of first trimming resistors Rt_1~Rt_n one by one, and are connected in parallel between the two ends of the corresponding first trimming resistors. Further, the first trimming control signal Trim1 has a plurality of binary digits.<Tn_tc :T1_tc> The first trimming control signal Trim1 controls the on and off of the corresponding first trimming switch according to the "1" (e.g., high level) or "0" (e.g., low level) of each digital bit to adjust the resistance value Rt of the temperature drift trimming unit 201. Furthermore, the resistance values ​​of the plurality of first trimming resistors Rt_1 to Rt_n are increased in a binary weighted manner.

[0048] Figure 5 FIG. 2 is a schematic circuit diagram of a temperature drift compensation unit according to an embodiment of the present invention. Figure 5As shown, the temperature drift compensation unit 202 includes a plurality of second trimming resistors Rs_1~Rs_n and a plurality of second trimming switches S2_1~S2_n, where n is an integer greater than 1. The plurality of second trimming resistors Rs_1~Rs_n are connected in series in sequence, and the plurality of second trimming switches S2_1~S2_n correspond one-to-one to the plurality of second trimming resistors Rs_1~Rs_n, and are connected in parallel between the two ends of the corresponding second trimming resistors. Further, the plurality of second trimming resistors Rs_1~Rs_n correspond one-to-one to the plurality of first trimming resistors Rt_1~Rt_n, and the resistance value of each second trimming resistor is k times the resistance value of the corresponding first trimming resistor, so that the equivalent resistance value Rs of the temperature drift compensation unit 202 is k times the equivalent resistance value Rt of the temperature drift trimming unit 201. Further, the k value is set by the ratio between the first equivalent resistance and the second equivalent resistance, the first equivalent resistance is equal to the sum of the resistances of the second resistor R2 and the equivalent resistance Rt of the temperature drift trimming unit 201, and the second equivalent resistance is equal to the equivalent resistance of the reference output module 220. Further, the first trimming control signal Trim1 has a plurality of binary digits.<Tn_tc :T1_tc> The first trimming control signal Trim1 controls the on and off of the corresponding second trimming switch according to the "1" (e.g., high level) or "0" (e.g., low level) of each digital bit to adjust the resistance value Rs of the temperature drift compensation unit 202. Furthermore, the resistance values ​​of the plurality of second trimming resistors Rs_1 to Rs_n are increased in a binary weighted manner.

[0049] Figure 6 FIG. 2 is a schematic circuit diagram of a voltage trimming unit according to an embodiment of the present invention. Figure 6 As shown, the voltage trimming unit 203 includes a plurality of third trimming resistors Rf_1~Rf_m and a plurality of third trimming switches S3_1~S3_m, where m is an integer greater than 1. The plurality of third trimming resistors Rf_1~Rf_m are connected in series, and the plurality of third trimming switches S3_1~S3_m correspond to the plurality of third trimming resistors Rf_1~Rf_m one by one, and are connected in parallel between the two ends of the corresponding third trimming resistors. Further, the second trimming control signal Trim2 has a plurality of binary digits.<Tm_offset :T1_toffset> The second trimming control signal Trim2 controls the on and off of the corresponding third trimming switch according to the "1" (e.g., high level) or "0" (e.g., low level) of each digital bit to adjust the resistance value Rf of the voltage trimming unit 203. Furthermore, the resistance values ​​of the plurality of third trimming resistors Rf_1 to Rf_m are increased in a binary weighted manner.

[0050] Figure 7FIG. 1 is a schematic diagram showing a waveform of a reference voltage of a bandgap reference circuit after temperature drift adjustment according to an embodiment of the present invention. Figure 7 In the embodiment of the present invention, the reference voltage V is taken as n=3 as an example. REF Perform a temperature scan simulation from -40℃ to 150℃. Figure 7 As shown, after adding the temperature drift compensation unit 202, the bandgap reference circuit 200 of the embodiment of the present invention can obtain a reference voltage V REF After temperature drift adjustment, no offset will occur and will not affect the use of the subsequent system.

[0051] In summary, compared with the prior art, the bandgap reference circuit of the embodiment of the present invention uses a temperature drift compensation unit to synchronously offset the offset introduced by the temperature drift adjustment unit in the reference reference voltage, thereby solving the problem of voltage value deviation of the reference reference voltage at room temperature caused by the existing temperature drift adjustment, and helps to optimize the adjustment method. It can not only ensure that the reference reference voltage is not affected by temperature conditions, but also ensure the consistency of the reference reference voltage, thereby better meeting application requirements.

[0052] It should be noted that although in this article, the device is described as a certain N-channel or P-channel device, or a certain N-type or P-type doped region, it can be understood by those skilled in the art that complementary devices can also be realized according to the present invention. It can be understood by those skilled in the art that the conductivity type refers to the mechanism by which the conduction occurs, such as conduction by holes or electrons, so the conductivity type does not involve the doping concentration but the doping type, such as P-type or N-type. It can be understood by those skilled in the art that the words "during", "when" and "when..." used in this article in connection with the operation of the circuit are not strict terms indicating the action that occurs immediately when the start-up action begins, but there may be some small but reasonable one or more delays between it and the reaction action initiated by the start-up action, such as various transmission delays, etc. The words "approximately" or "substantially" used in this article mean that the element value has a parameter that is expected to be close to the declared value or position. However, as is well known in the art, there are always slight deviations that make it difficult for the value or position to be strictly the declared value. It is well established in the art that a deviation of at least ten percent (10%) (or at least twenty percent (20%) for semiconductor doping concentrations) is a reasonable deviation from the desired goal of exactness as described. When used in conjunction with a signal state, the actual voltage value or logic state (e.g., "1" or "0") of the signal depends on whether positive or negative logic is used.

[0053] In addition, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0054] According to the embodiments of the present invention, as described above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can make good use of the present invention and the modified use based on the present invention. The scope of protection of the present invention shall be based on the scope defined by the claims of the present invention.

Claims

1. A bandgap reference circuit, comprising: A bandgap reference core module, used for generating a positive temperature coefficient voltage and a negative temperature coefficient voltage, and superimposing the positive temperature coefficient voltage and the negative temperature coefficient voltage on each other to generate a bandgap reference voltage; A reference output module, used for dividing the bandgap reference voltage to generate a reference reference voltage, The bandgap reference core module includes a temperature drift adjustment unit, and the temperature drift adjustment unit is used to adjust its own first resistance value according to a first adjustment control signal to adjust the positive temperature coefficient voltage, thereby realizing temperature drift adjustment of the bandgap reference voltage. The reference output module further includes a temperature drift compensation unit, which is used to adjust its own second resistance value according to the first trimming control signal to adjust the voltage division ratio of the reference output module, thereby eliminating the offset generated in the reference voltage during the temperature drift trimming process. Wherein, the ratio of the second resistance value of the temperature drift compensation unit to the first resistance value of the temperature drift adjustment unit is fixed.

2. The bandgap reference circuit according to claim 1, wherein: The bandgap reference core module further includes first and second bipolar transistors, first to third transistors, first to fifth resistors and an operational amplifier. The first end of the third resistor is connected to the power supply voltage, the second end of the third resistor is connected to the first end of the first transistor and the inverting input end of the operational amplifier, The control end of the first transistor is connected to the control end of the second transistor and the output end of the operational amplifier, and the second end of the first transistor is connected to the collector of the first bipolar transistor. The base of the first bipolar transistor is connected to the base of the second bipolar transistor, and the second end of the first bipolar transistor is connected to the first end of the first resistor. The second end of the first resistor is connected to the emitter of the second bipolar transistor and the first end of the second resistor, The second end of the second resistor is connected to the temperature drift adjustment unit, and the second end of the temperature drift adjustment unit is connected to the ground. A first end of a fourth resistor is connected to the power supply voltage, a second end of the fourth resistor is connected to the first end of the second transistor and the non-inverting input end of the operational amplifier, The second end of the second transistor is connected to the collector of the second bipolar transistor, A first end of the fifth resistor is connected to the power supply voltage, a second end of the fifth resistor is connected to a first end of the third transistor, The control end of the third transistor is connected to the output end of the operational amplifier, and the second end of the third transistor is connected to the collector of the second bipolar transistor. The emitter junction areas of the first bipolar transistor and the second bipolar transistor are different, and the collector of the second bipolar transistor is used to output the bandgap reference voltage.

3. The bandgap reference circuit according to claim 2, wherein: The temperature drift trimming unit includes a plurality of first trimming resistors and a plurality of first trimming switches, wherein the plurality of first trimming resistors are connected in series between the second end of the second resistor and the ground, the plurality of first trimming switches correspond one-to-one to the plurality of first trimming resistors, and the conduction and disconnection of the plurality of first trimming switches are controlled by the first trimming control signal.

4. The bandgap reference circuit according to claim 3, wherein: The reference output module includes the temperature drift compensation unit, a sixth resistor and a seventh resistor, Wherein, the temperature drift compensation unit includes a plurality of second trimming resistors and a plurality of second trimming switches, the plurality of second trimming resistors, the sixth resistor and the seventh resistor are connected in series between the bandgap reference voltage and ground, the intermediate node between the sixth resistor and the seventh resistor is used to output the reference reference voltage, the plurality of second trimming switches correspond one-to-one to the plurality of second trimming resistors, and the conduction and disconnection of the plurality of second trimming switches are controlled by the first trimming control signal.

5. The bandgap reference circuit according to claim 4, wherein: The multiple second trimming resistors correspond one-to-one to the multiple first trimming resistors, and the resistance value of each second trimming resistor is k times the resistance value of the corresponding first trimming resistor, wherein k is set by a ratio between a first equivalent resistance value and a second equivalent resistance value, the first equivalent resistance value is equal to the sum of the resistances of the second resistor and the temperature drift trimming unit, and the second equivalent resistance value is equal to the equivalent resistance value of the reference output module.

6. The bandgap reference circuit according to claim 5, wherein: The reference output module also includes: The voltage trimming unit is used to adjust its own third resistance value according to the second trimming control signal to adjust the voltage division ratio of the reference output module, thereby eliminating the offset voltage generated by the operational amplifier.

7. The bandgap reference circuit according to claim 6, wherein: The voltage trimming unit includes a plurality of third trimming resistors and a plurality of third trimming switches, the plurality of third trimming resistors are connected in series, the plurality of third trimming switches correspond one to one to the plurality of third trimming resistors, and the turning on and off of the plurality of third trimming switches are controlled by the second trimming control signal.

8. The bandgap reference circuit according to claim 7, wherein: The resistance values ​​of the first trimming resistors, the second trimming resistors and the third trimming resistors are increased in binary weighted order.

9. The bandgap reference circuit according to claim 8, wherein: The first trimming control signal and the second trimming control signal respectively include a multi-bit binary code.

10. The bandgap reference circuit according to claim 2, wherein: The first bipolar transistor and the second bipolar transistor are NPN transistors, and the first transistor to the third transistor are NMOS transistors.

Images