Bandgap reference circuit, current compensation method and reference power supply

Abstract

This application provides a bandgap reference circuit, a current compensation method, and a reference power supply. The bandgap reference circuit includes a first transistor module, a second transistor module, a first resistor module, a second resistor module, a first compensation branch, and a second compensation branch. The first compensation branch generates a first compensation current, which compensates for a first current flowing from the first terminal of the first transistor module to its third terminal, and the first compensation current is equal to the first current. The second compensation branch generates a second compensation current, which compensates for a second current flowing from the first terminal of the second transistor module to its third terminal, and the second compensation current is equal to the second current. This application solves the problem that existing bandgap reference circuits cannot guarantee precise matching of the collector currents of the two BJTs in the two branches, which leads to reduced accuracy and increased temperature drift of the reference voltage output by the bandgap reference circuit, seriously affecting the stability and reliability of the reference voltage.

Description

Technical Field

[0001] This application belongs to the field of reference power supply technology, and particularly relates to a bandgap reference circuit, a current compensation method, and a reference power supply. Background Technology

[0002] As a core fundamental module of analog integrated circuits and mixed-signal systems, the bandgap reference circuit's core objective is to generate a high-precision, temperature-independent reference voltage. This provides a stable reference for downstream modules such as analog-to-digital converters, voltage regulators, and comparators, and its performance directly determines the accuracy and reliability of the entire electronic system. In practical chip design, bipolar junction transistors (BJTs) are particularly important due to their defined negative temperature coefficient emitter-junction voltage (V0). BE ), and the voltage difference between the emitter junctions of the two transistors (ΔV) BE It exhibits a positive temperature coefficient, becoming a core functional component of the bandgap reference circuit, through V BE With ΔV BE The temperature drift complementarity enables the output of a temperature-independent reference voltage.

[0003] However, in low gain (low β) process scenarios, the current path between the base and emitter of a BJT causes a large amount of base current to flow directly into the emitter, resulting in the emitter output current containing a base current component. In a bandgap reference circuit, ideally, the collector currents of the two BJT branches should be equal (i.e., I0). c1 =I c2 ), to ensure ΔV BE The positive temperature coefficient stability is achieved, thus enabling accurate temperature compensation. However, in low-β scenarios, the base current brought by the base-emitter current path will shunt the total current of the branch, so that the current flowing through the resistor module is not a pure collector current, but a superposition of the collector current and the base current. Ultimately, it is impossible to guarantee the accurate matching of the collector currents of the two branches of the BJT, which leads to a decrease in the accuracy of the reference voltage output by the bandgap reference circuit and an increase in temperature drift, seriously affecting the stability and reliability of the reference voltage. Summary of the Invention

[0004] This application provides a bandgap reference circuit, a current compensation method, and a reference power supply, which can solve the problem that existing bandgap reference circuits cannot guarantee the precise matching of the collector currents of the two BJT branches, thus leading to a decrease in the accuracy of the reference voltage output by the bandgap reference circuit, an increase in temperature drift, and a serious impact on the stability and reliability of the reference voltage.

[0005] In a first aspect, embodiments of this application provide a bandgap reference circuit, including a first transistor module, a second transistor module, a first resistor module, a second resistor module, a first compensation branch, and a second compensation branch. The first terminals of both the first and second transistor modules are used to receive a reference voltage. The second terminals of both the first and second transistor modules are used to be electrically connected to a power supply. The third terminal of the first transistor module is electrically connected to the first terminal of the first resistor module. The third terminal of the second transistor module is electrically connected to both the second terminal of the first resistor module and the first terminal of the second resistor module. The second terminal of the second resistor module is grounded. The first compensation branch is a branch between the third terminal of the first transistor module and ground, and the second compensation branch is a branch between the third terminal of the second transistor module and ground.

[0006] The first compensation branch is used to generate a first compensation current, which is used to compensate for the first current flowing from the first terminal of the first transistor module to the third terminal of the first transistor module, and the first compensation current is equal to the first current; the second compensation branch is used to generate a second compensation current, which is used to compensate for the second current flowing from the first terminal of the second transistor module to the third terminal of the second transistor module, and the second compensation current is equal to the second current.

[0007] In one possible implementation of the first aspect, the bandgap reference circuit further includes a third compensation branch and a fourth compensation branch, wherein the third compensation branch is a branch between the power supply and the second terminal of the first transistor module, and the fourth compensation branch is a branch between the power supply and the second terminal of the second transistor module.

[0008] The third compensation branch is used to generate a first compensation leakage current, which is used to compensate for the first leakage current at the fourth terminal of the first transistor module, and the first compensation leakage current is equal to the first leakage current; the fourth compensation branch is used to generate a second compensation leakage current, which is used to compensate for the second leakage current at the fourth terminal of the second transistor module, and the second compensation leakage current is equal to the second leakage current.

[0009] In one possible implementation of the first aspect, the first transistor module includes a first transistor, the base of the first transistor serving as a first terminal of the first transistor module for receiving the reference voltage, the collector of the first transistor serving as a second terminal of the first transistor module for electrical connection to the power supply, the emitter of the first transistor serving as a third terminal of the first transistor module for electrical connection to the first terminal of the first resistor module, and the substrate of the first transistor serving as a fourth terminal of the first transistor module.

[0010] In one possible implementation of the first aspect, the second transistor module includes a base of the second transistor as a first terminal of the second transistor module for receiving the reference voltage, a collector of the second transistor as a second terminal of the second transistor module for electrical connection to the power supply, an emitter of the second transistor as a third terminal of the second transistor module for electrical connection to the second terminal of the first resistor module and the first terminal of the second resistor module, respectively, and a substrate of the second transistor as a fourth terminal of the second transistor module.

[0011] In one possible implementation of the first aspect, the first resistor module includes a first resistor, a first end of the first resistor serving as the first end of the first resistor module and electrically connected to the third end of the first transistor module, and a second end of the first resistor serving as the second end of the first resistor module and electrically connected to the third end of the second transistor module and the first end of the second resistor module, respectively.

[0012] In one possible implementation of the first aspect, the second resistor module includes a second resistor, the first end of the second resistor serving as the first end of the second resistor module and electrically connected to the second end of the first resistor module and the third end of the second transistor, respectively, and the second end of the second resistor serving as the second end of the second resistor module and grounded.

[0013] Secondly, embodiments of this application provide a current compensation method applied to the bandgap reference circuit described in any one of the first aspects, the current compensation method comprising:

[0014] A first compensation current is generated through a first compensation branch, which is a branch between the third terminal of the first transistor module and ground. The first compensation current is used to compensate for the first current flowing from the first terminal of the first transistor module to the third terminal of the first transistor module. The magnitude of the first compensation current is equal to that of the first current.

[0015] A second compensation current is generated through a second compensation branch, which is the branch between the third terminal of the second transistor module and ground. The second compensation current is used to compensate for the second current flowing from the first terminal of the second transistor module to the third terminal of the second transistor module. The magnitude of the second compensation current is equal to that of the second current.

[0016] In one possible implementation of the second aspect, the current compensation method further includes:

[0017] A first compensation leakage current is generated through a third compensation branch, which is a branch between the power supply and the second terminal of the first transistor module. The first compensation leakage current is used to compensate for the first leakage current at the fourth terminal of the first transistor module. The first compensation leakage current is equal to the first leakage current.

[0018] A second compensation leakage current is generated through a fourth compensation branch, which is the branch between the power supply and the second terminal of the second transistor module. The second compensation leakage current is used to compensate for the second leakage current at the fourth terminal of the second transistor module, and the second compensation leakage current is equal to the second leakage current.

[0019] In one possible implementation of the second aspect, the current compensation method further includes:

[0020] The first current, the second current, the first leakage current, and the second leakage current are collected by the sampling unit;

[0021] Based on the first current, the second current, the first leakage current, and the second leakage current, determine the corresponding first compensation current, second compensation current, first compensation leakage current, and second compensation leakage current.

[0022] Thirdly, embodiments of this application provide a reference power supply, including the bandgap reference circuit described in any one of the first aspects.

[0023] The beneficial effects of the embodiments in this application compared with the prior art are:

[0024] The bandgap reference circuit provided in this application includes a first transistor module, a second transistor module, a first resistor module, a second resistor module, a first compensation branch, and a second compensation branch. The first compensation branch is the branch between the third terminal of the first transistor module and ground, and the second compensation branch is the branch between the third terminal of the second transistor module and ground. The first compensation branch generates a first compensation current, which compensates for a first current flowing from the first terminal of the first transistor module to the third terminal of the first transistor module, and the first compensation current is equal to the first current. The second compensation branch generates a second compensation current, which compensates for a second current flowing from the first terminal of the second transistor module to the third terminal of the second transistor module, and the second compensation current is equal to the second current.

[0025] Through the above design, the first compensation current can accurately cancel the first current, and the second compensation current can accurately cancel the second current. This is equivalent to removing the first current that would originally be transmitted to the third terminal of the first transistor module and the second current that would be transmitted to the third terminal of the second transistor module and diverting them to ground, thereby effectively eliminating the current component of the first terminal of the transistor module in the branch current, making the current flowing through the resistor module a pure current of the second terminal of the transistor module. On this basis, it can be ensured that the currents at the second terminals of the two transistor modules are precisely equal, ensuring the stability of the emitter-junction voltage difference in the bandgap reference circuit. Thus, it can be seen that the bandgap reference circuit of this application, by accurately canceling the non-negligible current interference in low amplification (low β) scenarios through a dedicated compensation branch, effectively solves the technical problems in the prior art where the base-emitter current path under low β processes leads to branch current doping and low collector current matching accuracy, resulting in large reference voltage temperature drift and insufficient accuracy. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a circuit diagram of an existing bandgap reference circuit;

[0028] Figure 2 This is a schematic block diagram of a bandgap reference circuit provided in an embodiment of this application;

[0029] Figure 3 This is a schematic block diagram of a bandgap reference circuit provided in another embodiment of this application;

[0030] Figure 4This is a circuit connection diagram of a bandgap reference circuit provided in an embodiment of this application.

[0031] In the diagram, 101 is the first transistor module; 102 is the second transistor module; 103 is the first resistor module; 104 is the second resistor module; 105 is the first compensation branch; 106 is the second compensation branch; 107 is the third compensation branch; and 108 is the fourth compensation branch. Detailed Implementation

[0032] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0033] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0034] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0035] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0036] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0038] like Figure 1 As shown, the existing bandgap reference circuit consists of two transistors, two resistors, and a comparator. In actual chip design, bipolar junction transistors (BJTs) are preferred due to their distinct negative temperature coefficient emitter-junction voltage (V). BE ),Right now And the voltage difference between the emitter junctions of the two transistors (ΔV) BE It exhibits a positive temperature coefficient, that is The principle will be derived and analyzed below using formulas.

[0039] V BE Differentiating with respect to temperature T, we get:

[0040]

[0041] The collector current I of the BJT transistor C satisfy:

[0042]

[0043] Among them, the emitter voltage V of the BJT transistor BE for:

[0044]

[0045] Thermoelectric potential V T for:

[0046]

[0047] The voltage difference ΔV between the emitter and junction of the two transistors can be calculated. BE for:

[0048]

[0049] The voltage difference ΔV between the emitter and junction of the two transistors BE Differentiating with respect to temperature T, we get:

[0050]

[0051] In the above formula, V BE1 V is the emitter junction voltage of Q1. BE2 Ic1 is the emitter junction voltage of Q2, Ic2 is the collector current of Q1, and Ic2 is the collector current of Q2. s For saturation current, I s1 Let I be the saturation current of Q1. s2 I is the saturation current of Q2. s1 The emitter junction area A1 of Q1 is proportional to I. s2 The area of ​​the emitter junction A2 is proportional to that of Q2, where m is the diffusion coefficient of the PN junction, and E g Let be the bandgap energy, q be the unit charge, T be the absolute temperature scale, and n be the emitter area ratio of the two BJT transistors, i.e.: .

[0052] From the above, we can see that ΔV BE Since it is a voltage with a positive temperature coefficient, it can be obtained through V. BE With ΔV BE Temperature drift complementarity, through compensation by a certain coefficient, can achieve the output of a temperature-independent reference voltage.

[0053] The following is combined Figure 1 The relationship between reference voltage and temperature is derived and described.

[0054] Reference voltage V bg for:

[0055]

[0056] in:

[0057]

[0058] When designing a circuit, we ensure that Ic1 = Ic2. Therefore, we can obtain the simplified expression:

[0059]

[0060] Reference voltage V bg Taking the derivative with respect to temperature T, we can obtain:

[0061]

[0062] And, if you want According to the above formula, we can obtain It is a negative value. It is a positive value. Therefore, by adjusting... It can make Further simplification of the formula yields:

[0063]

[0064] If Ic1 / Ic2=1, and n is known to be a constant, then we can obtain:

[0065]

[0066] Further simplification of the formula yields:

[0067]

[0068] For BJT tubes Usually in .

[0069] It is not difficult to see from the above derivation process that the calculation involves... V BE The two BJT transistors have unequal emitter junction areas, and the conclusion that the collector currents Ic1 and Ic2 flowing through them are equal is a necessary condition for the conclusion to hold. In reality, the currents flowing into R1 and R2 are not only Ic1 and Ic2, but also include the current Ib from the BJT base. For BJTs with a large β = Ic / Ib value, Ib can be ignored. However, for low-β processes, the above formula is not accurate, and the impact of Ib cannot be ignored. That is, in low-β scenarios, the base current from the base-emitter current path will shun the total branch current, making the current flowing through the resistor module not purely the collector current, but the superposition of the collector current and the base current. At this time, the reference voltage V... bg for:

[0070]

[0071] At this time, the reference voltage V bg The introduction of β, which varies considerably with temperature and process conditions, makes it impossible to guarantee precise matching of the collector currents of the two BJT branches. This leads to a decrease in the accuracy of the reference voltage output by the bandgap reference circuit and an increase in temperature drift, severely affecting the stability and reliability of the reference voltage.

[0072] To address the aforementioned issues, the bandgap reference circuit provided in this application includes a first transistor module, a second transistor module, a first resistor module, a second resistor module, a first compensation branch, and a second compensation branch. The first compensation branch is the branch between the third terminal of the first transistor module and ground, and the second compensation branch is the branch between the third terminal of the second transistor module and ground. The first compensation branch generates a first compensation current, which compensates for a first current flowing from the first terminal of the first transistor module to the third terminal of the first transistor module, and the first compensation current is equal to the first current. The second compensation branch generates a second compensation current, which compensates for a second current flowing from the first terminal of the second transistor module to the third terminal of the second transistor module, and the second compensation current is equal to the second current.

[0073] Through the above design, the first compensation current can accurately cancel the first current, and the second compensation current can accurately cancel the second current. This is equivalent to removing the first current that would originally be transmitted to the third terminal of the first transistor module and the second current that would be transmitted to the third terminal of the second transistor module and diverting them to ground, thereby effectively eliminating the current component of the first terminal of the transistor module in the branch current, making the current flowing through the resistor module a pure current of the second terminal of the transistor module. On this basis, it can be ensured that the currents at the second terminals of the two transistor modules are precisely equal, ensuring the stability of the emitter-junction voltage difference in the bandgap reference circuit. Thus, it can be seen that the bandgap reference circuit of this application, by accurately canceling the non-negligible current interference in low amplification (low β) scenarios through a dedicated compensation branch, effectively solves the technical problems in the prior art where the base-emitter current path under low β processes leads to branch current doping and low collector current matching accuracy, resulting in large reference voltage temperature drift and insufficient accuracy.

[0074] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0075] Figure 2 A schematic block diagram of a bandgap reference circuit according to an embodiment of this application is shown. See also... Figure 2As shown, the bandgap reference circuit includes a first transistor module 101, a second transistor module 102, a first resistor module 103, a second resistor module 104, a first compensation branch 105, and a second compensation branch 106. The first terminal of the first transistor module 101 and the first terminal of the second transistor module 102 are both used to receive the reference voltage. The second terminal of the first transistor module 101 and the second terminal of the second transistor module 102 are both used to be electrically connected to the power supply. The third terminal of the first transistor module 101 is electrically connected to the first terminal of the first resistor module 103. The third terminal of the second transistor module 102 is electrically connected to the second terminal of the first resistor module 103 and the first terminal of the second resistor module 104, respectively. The second terminal of the second resistor module 104 is grounded. The first compensation branch 105 is the branch between the third terminal of the first transistor module 101 and ground. The second compensation branch 106 is the branch between the third terminal of the second transistor module 102 and ground.

[0076] Specifically, the first compensation branch 105 is used to generate a first compensation current Ib2, which is used to compensate for the first current Ib1 flowing from the first terminal of the first transistor module 101 to the third terminal of the first transistor module 101. The first compensation current Ib2 is equal to the first current Ib1. The second compensation branch 106 is used to generate a second compensation current Ib4, which is used to compensate for the second current Ib3 flowing from the first terminal of the second transistor module 102 to the third terminal of the second transistor module 102. The second compensation current Ib4 is equal to the second current Ib3.

[0077] Through the above design, the first compensation current Ib2 can accurately cancel the first current Ib1, and the second compensation current Ib4 can accurately cancel the second current Ib3. This is equivalent to removing the first current Ib1, which would originally be transmitted to the third terminal of the first transistor module 101, and the second current Ib3, which would be transmitted to the third terminal of the second transistor module 102, and directing them to ground. This effectively eliminates the current component of the first terminal of the transistor module in the branch current, making the current flowing through the resistor module a pure current of the second terminal of the transistor module. On this basis, it can be ensured that the currents at the second terminals of the two transistor modules are precisely equal, ensuring the stability of the emitter-junction voltage difference in the bandgap reference circuit. Thus, the bandgap reference circuit of this application effectively solves the technical problems of large temperature drift and insufficient accuracy of the reference voltage caused by the branch current doping and low collector current matching accuracy in the base-emitter current path under low-β process in the prior art, by accurately canceling the non-negligible current interference in low amplification (low β) scenarios through a dedicated compensation branch.

[0078] It should be noted that the first current Ib1 flows from the first terminal of the first transistor module 101 to the third terminal, while the first compensation branch 105 is connected between the third terminal of the first transistor module 101 and ground, and the first compensation current Ib2 generated by it flows from the third terminal of the first transistor module 101 to ground. Since the two branches form a current convergence at the third terminal of the first transistor module 101, the first compensation current Ib2 can accurately draw away the first current Ib1 flowing into the third terminal and guide it to ground through its own path, thereby canceling the interference of the first current Ib1 on the total current of the branch.

[0079] The second current Ib3 flows from the first terminal to the third terminal of the second transistor module 102, while the second compensation branch 106 connects the third terminal of the second transistor module 102 to ground, and the second compensation current Ib4 generated thereflows from the third terminal of the second transistor module 102 to ground. Since the two branches converge at the third terminal of the second transistor module 102, the second compensation current Ib4 can precisely draw away the second current Ib3 flowing into the third terminal and guide it to ground through its own path, thereby canceling the interference of the second current Ib3 on the total current of the branch.

[0080] It should be noted that, compared with existing technologies that involve increasing device size and using simple resistor compensation, this application does not require a large amount of additional chip area or complex process optimization. It can achieve dynamic and accurate compensation of base current through a simple compensation branch. While ensuring high accuracy and low temperature drift performance of the reference voltage, it also takes into account the requirements of circuit miniaturization and low cost, making it suitable for scenarios with stringent reference performance requirements such as industrial control and automotive electronics, and thus more practical.

[0081] It should be noted that, due to the influence of actual processes, leakage current may occur between the BJT and the substrate under high temperature conditions. This can introduce uncontrollable factors into the current flowing into the resistor module, which may result in a lower reference voltage value.

[0082] Based on this issue, such as Figure 3 As shown, the bandgap reference circuit also includes a third compensation branch 107 and a fourth compensation branch 108. The third compensation branch 107 is the branch between the power supply and the second terminal of the first transistor module 101, and the fourth compensation branch 108 is the branch between the power supply and the second terminal of the second transistor module 102.

[0083] Specifically, the third compensation branch 107 is used to generate a first compensation leakage current IL2, which is used to compensate for the first leakage current IL1 at the fourth terminal (substrate) of the first transistor module 101. The first compensation leakage current IL2 is equal to the first leakage current IL1. The fourth compensation branch 108 is used to generate a second compensation leakage current IL4, which is used to compensate for the second leakage current IL3 at the fourth terminal (substrate) of the second transistor module 102. The second compensation leakage current IL4 is equal to the second leakage current IL3.

[0084] By using the above-mentioned dual leakage current compensation branch design, the parasitic leakage current interference between the BJT and the substrate under high temperature environment can be accurately offset, effectively eliminating the uncontrollable leakage current component in the current flowing into the resistor module, ensuring that the current flowing through the resistor module is always the pure BJT collector current, maintaining the precise matching of the collector currents of the two branches, thereby avoiding the problem of the reference voltage being too low due to high temperature leakage, and significantly improving the working stability, voltage accuracy and temperature drift suppression capability of the bandgap reference circuit in a wide temperature range (especially in high temperature scenarios).

[0085] It should be noted that the first leakage current IL1 flows from the fourth terminal of the first transistor module 101 to ground, while the first compensation leakage current IL2 generated by the third compensation branch 107 flows from the power supply to the second terminal of the first transistor module 101. The first compensation leakage current IL2 can accurately compensate for the first leakage current IL1 flowing from the fourth terminal, thereby canceling the interference of the first leakage current IL1 on the total current of the branch.

[0086] The second leakage current IL3 flows from the fourth terminal of the second transistor module 102 to ground, while the second compensation leakage current IL4 generated by the fourth compensation branch 108 flows from the power supply to the second terminal of the second transistor module 102. The second compensation leakage current IL4 can accurately compensate for the second leakage current IL3 flowing out from the fourth terminal, thereby canceling the interference of the second leakage current IL3 on the total current of the branch.

[0087] The following is combined Figure 4 The circuit diagram shown provides a detailed description of the working principle of the bandgap reference circuit provided in the embodiments of this application.

[0088] In one embodiment of this application, such as Figure 4 As shown, the first transistor module 101 includes a first transistor Q1. The base of the first transistor Q1 serves as the first terminal of the first transistor module 101, used to receive a reference voltage V. bg The collector of the first transistor Q1 serves as the second terminal of the first transistor module 101, and is used to connect to the power supply V. DDElectrically connected, the emitter of the first transistor Q1 serves as the third terminal of the first transistor module 101 and is electrically connected to the first terminal of the first resistor module 103, and the substrate of the first transistor Q1 serves as the fourth terminal of the first transistor module 101.

[0089] Specifically, the first transistor Q1 can form a stable negative temperature coefficient emitter junction voltage through its own emitter junction, providing basic electrical characteristics for temperature compensation of the bandgap reference circuit; at the same time, with its own current amplification and current control characteristics, it can accurately regulate the current path between the collector and emitter, ensuring the controllability and stability of the current flowing through the first transistor Q1, providing reliable current characteristic support for the subsequent circuit to achieve precise collector current matching and finally generate a temperature-independent reference voltage.

[0090] For example, the designer can select the type of the first transistor Q1 according to the actual situation. For instance, the first transistor Q1 can be selected as NPN type.

[0091] In one embodiment of this application, such as Figure 4 As shown, the second transistor module 102 includes the base of the second transistor Q2 as the first terminal of the second transistor module 102, used to receive the reference voltage V. bg The collector of the second transistor Q2 serves as the second terminal of the second transistor module 102, and is used to connect to the power supply V. DD Electrically connected, the emitter of the second transistor Q2 serves as the third terminal of the second transistor module 102, and is electrically connected to the second terminal of the first resistor module 103 and the first terminal of the second resistor module 104, respectively. The substrate of the second transistor Q2 serves as the fourth terminal of the second transistor module 102.

[0092] Specifically, the second transistor Q2 can form a stable negative temperature coefficient emitter junction voltage through its own emitter junction, providing the basic electrical characteristics for temperature compensation of the bandgap reference circuit; at the same time, with its own current amplification and current control characteristics, it can accurately regulate the current path between the collector and emitter, ensuring the controllability and stability of the current flowing through the second transistor Q2, providing reliable current characteristic support for the subsequent accurate matching of the collector current and the final generation of a temperature-independent reference voltage.

[0093] For example, the designer can select the type of the first transistor Q1 according to the actual situation. For instance, the first transistor Q1 can be selected as NPN type.

[0094] In one embodiment of this application, such as Figure 4As shown, the first resistor module 103 includes a first resistor R1. The first end of the first resistor R1 serves as the first end of the first resistor module 103 and is electrically connected to the third end of the first transistor module 101. The second end of the first resistor R1 serves as the second end of the first resistor module 103 and is electrically connected to the third end of the second transistor module 102 and the first end of the second resistor module 104, respectively.

[0095] Specifically, the emitter current of the first transistor Q1 flows through the first resistor R1, creating a stable positive temperature coefficient voltage drop across R1. This voltage drop is the emitter-junction voltage difference ΔV required to achieve temperature compensation. BE This can complement the negative temperature coefficient voltage of the emitter junction of the first transistor Q1, laying the foundation for the bandgap reference circuit to achieve a temperature-independent reference voltage output. At the same time, the first resistor R1, as an intermediate bridge connecting the second resistor module 104, also transmits the current output from the emitter of the first transistor Q1 to the second resistor module 104.

[0096] In one embodiment of this application, such as Figure 4 As shown, the second resistor module 104 includes a second resistor R2. The first end of the second resistor R2 serves as the first end of the second resistor module 104 and is electrically connected to the second end of the first resistor module 103 and the third end of the second transistor Q2. The second end of the second resistor R2 serves as the second end of the second resistor module 104 and is grounded.

[0097] Specifically, the second resistor R2 receives the current output from the emitters of the first transistor Q1 and the second transistor Q2, and forms a stable voltage drop across R2 to ensure the normal flow of operating current through the first transistor Q1, the second transistor Q2, and the first resistor R1. Furthermore, the resistance relationship between the second resistor R2 and the first resistor R1 allows for adjustment of the reference voltage output amplitude through resistance value adaptation, catering to the voltage reference requirements of different application scenarios.

[0098] For example, designers can set the resistance ratio of the first resistor R1 and the second resistor R2 according to actual application requirements. For instance, the resistance of the first resistor R1 can be set to twice the resistance of the second resistor R2, i.e., R1 = 2R2. In the current path of this bandgap reference circuit, the current flowing through the first resistor R1 is the output current of the emitter of the first transistor Q1, while the current flowing through the second resistor R2 is the sum of the output currents of the emitters of the first transistor Q1 and the second transistor Q2. Based on this specific current distribution characteristic, setting the resistance of the first resistor R1 to twice that of the second resistor R2 allows the positive temperature coefficient emitter junction voltage difference ΔV formed on the first resistor R1 to be... BE The negative temperature coefficient of the emitter junction and the emitter junction voltage V of the transistor. BEThis achieves precise temperature drift compensation, thereby ensuring that the bandgap reference circuit outputs a stable, temperature-independent reference voltage.

[0099] In summary, since this solution can compensate for the first current Ib1, the second current Ib3, the first leakage current IL1, and the second leakage current IL3, it can ensure that the emitter output current I1 of the first transistor Q1 and the emitter output current I2 of the second transistor Q2 do not change with temperature, which can greatly reduce the temperature drift of the reference circuit. It is also easy to implement when designing the two resistor proportional coefficients for compensation.

[0100] After the above compensation, we can obtain:

[0101]

[0102] The reference voltage V can be obtained through calculation. bg :

[0103]

[0104] If and only if The equation is only valid if the coefficient is not 2; otherwise, an error will be introduced if the coefficient is not 2.

[0105] Reference voltage V bg Taking the derivative with respect to temperature T, we can obtain:

[0106]

[0107] It should be noted that traditional solutions typically require a large number of BJT devices to simulate the high-temperature substrate leakage characteristics of the main circuit transistors for leakage current compensation. A large number of BJT devices occupy a significant portion of the chip's effective area, increasing both the complexity of circuit layout design and hardware costs. This application, however, uses smaller BJTs to accurately simulate the high-temperature substrate leakage characteristics of the main circuit transistors. The simulated leakage current signal is then amplified using a current mirror circuit, allowing the simulated leakage current to precisely match the required compensation leakage current amplitude, thus achieving effective leakage current compensation. This design significantly reduces the number of BJT devices and the size percentage of each device while maintaining the accuracy of high-temperature leakage current simulation and compensation. This effectively saves chip area, reduces layout design complexity, and simultaneously addresses the requirements of circuit miniaturization and low-cost design.

[0108] This application also discloses a current compensation method applied to the aforementioned bandgap reference circuit. The current compensation method includes:

[0109] A first compensation current is generated through a first compensation branch, which is the branch between the third terminal of the first transistor module and ground. The first compensation current is used to compensate for the first current flowing from the first terminal of the first transistor module to the third terminal of the first transistor module. The magnitude of the first compensation current is equal to that of the first current.

[0110] A second compensation current is generated through a second compensation branch, which is the branch between the third terminal of the second transistor module and ground. The second compensation current is used to compensate for the second current flowing from the first terminal of the second transistor module to the third terminal of the second transistor module. The magnitude of the second compensation current is equal to that of the second current.

[0111] Specifically, the current compensation method of this application is applied to the aforementioned bandgap reference circuit, and solves the problem of branch current interference caused by the base-emitter current path in low amplification scenarios through targeted current compensation operation. This method generates a first compensation current and a second compensation current, equal in magnitude to the first current and the second current, respectively, in a dedicated compensation branch between the third terminal of the transistor module and ground. This precisely compensates for the current flowing from the first terminal to the third terminal of the transistor module. By utilizing the direction of the compensation current flowing from the third terminal to ground, the first and second currents mixed into the branch are directly extracted. From the perspective of current regulation, this effectively eliminates the non-collector current component in the current flowing into the resistor module branch, ensuring that the current flowing through the resistor module remains a pure transistor collector current. This, in turn, ensures the precise matching of the collector currents of the two branches in the bandgap reference circuit, ensuring the emitter-junction voltage difference ΔV. BE Stable generation and temperature drift complement each other.

[0112] In one embodiment of this application, the current compensation method further includes:

[0113] The first compensation leakage current is generated through the third compensation branch, which is the branch between the power supply and the second terminal of the first transistor module. The first compensation leakage current is used to compensate the first leakage current at the fourth terminal of the first transistor module. The first compensation leakage current is equal to the first leakage current.

[0114] The second compensation leakage current is generated through the fourth compensation branch, which is the branch between the power supply and the second terminal of the second transistor module. The second compensation leakage current is used to compensate for the second leakage current at the fourth terminal of the second transistor module, and the second compensation leakage current is equal to the second leakage current.

[0115] Specifically, based on base current compensation, this embodiment adds a specific compensation step for high-temperature substrate leakage current, further improving the current compensation system of the bandgap reference circuit and achieving dual accurate compensation of base current and substrate leakage current. This method generates a first compensation leakage current and a second compensation leakage current equal in magnitude to the first and second leakage currents respectively through a third and fourth compensation branch set between the power supply and the second terminal of the transistor module. This provides targeted compensation for the high-temperature parasitic leakage current at the substrate terminals of the first and second transistor modules, effectively offsetting the leakage interference from the BJT to the substrate under high-temperature conditions in actual processes. It eliminates the uncontrollable component of the leakage current in the branch current, preventing deviations in the current flowing into the resistor module due to leakage current shunting, and further ensuring that the current flowing through the resistor module is always a pure transistor collector current, continuously maintaining accurate matching of the collector currents of the two branches.

[0116] In one embodiment of this application, the current compensation method further includes:

[0117] The first current, the second current, the first leakage current, and the second leakage current are collected through the sampling unit.

[0118] Based on the first current, the second current, the first leakage current, and the second leakage current, determine the corresponding first compensation current, second compensation current, first compensation leakage current, and second compensation leakage current.

[0119] Specifically, by sampling the first current, second current, first leakage current, and second leakage current in real time, the system can accurately capture the dynamic changes in current values ​​caused by factors such as actual process deviations, temperature fluctuations, and power supply voltage changes, rather than using fixed-value compensation. This effectively solves the problems of fixed compensation being unable to adapt to changes in operating conditions and having insufficient compensation accuracy. In addition, by simultaneously sampling the four types of currents to be compensated and determining the four types of compensation currents accordingly, the system ensures the synchronization and matching of base current compensation and substrate leakage current compensation. This further ensures that the collector current flowing through the resistor module remains pure and matched, improving the operational stability of the bandgap reference circuit from the source of current regulation.

[0120] Meanwhile, the sampling step is logically simple, and the sampling results can be directly used as the basis for generating the compensation current without complicated calculations or conversions. It can be seamlessly connected with the subsequent compensation current generation step, improving the compensation effect without increasing the overall working complexity of the circuit, thus balancing compensation accuracy and implementation efficiency.

[0121] This application also discloses a reference power supply, including the aforementioned bandgap reference circuit. By employing this bandgap reference circuit, the reference power supply can solve the problems of base current interference under low amplification processes and branch current mismatch caused by substrate parasitic leakage current under high-temperature conditions. Through precise dual compensation of base current and substrate leakage current, combined with the dynamic adaptation compensation characteristics brought by real-time sampling, it ensures that the output reference voltage always maintains low temperature drift and high amplitude stability, effectively avoiding situations where the reference voltage is too low or drifts due to process deviations, temperature fluctuations, or power supply changes. This reference power supply can operate stably and continuously under complex conditions such as low amplification and high temperature, providing a high-precision, high-reliability voltage reference for downstream functional modules in various electronic systems such as industrial control, automotive electronics, precision measurement, and analog-to-digital conversion. This significantly improves the working accuracy and operational stability of the entire electronic system, adapting to the stringent application requirements of various industries for reference power supplies.

[0122] Meanwhile, since the bandgap reference circuit adopts a simple branch compensation structure, there is no need to add complex control and sampling devices, which will not increase the overall design complexity and hardware cost of the reference power supply, thus taking into account the power supply's performance improvement and miniaturization and low-cost design requirements.

[0123] Since the processing and functions implemented by the reference power supply in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned bandgap reference circuit, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0124] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A bandgap reference circuit, characterized in that, The device includes a first transistor module, a second transistor module, a first resistor module, a second resistor module, a first compensation branch, and a second compensation branch. The bases of both the first and second transistor modules are used to receive a reference voltage. The collectors of both the first and second transistor modules are used to be electrically connected to a power supply. The emitter of the first transistor module is electrically connected to the first terminal of the first resistor module. The emitter of the second transistor module is electrically connected to the second terminal of both the first and second resistor modules. The second terminal of the second resistor module is grounded. The first compensation branch is the branch between the emitter of the first transistor module and ground, and the second compensation branch is the branch between the emitter of the second transistor module and ground. The first compensation branch is used to generate a first compensation current, which is used to compensate for the first current flowing from the base of the first transistor module to the emitter of the first transistor module. The first compensation current is equal to the first current. The second compensation branch is used to generate a second compensation current, which is used to compensate for the second current flowing from the base of the second transistor module to the emitter of the second transistor module. The second compensation current is equal to the second current. The bandgap reference circuit further includes a third compensation branch and a fourth compensation branch. The third compensation branch is the branch between the power supply and the collector of the first transistor module, and the fourth compensation branch is the branch between the power supply and the collector of the second transistor module. The third compensation branch is used to generate a first compensation leakage current, which is used to compensate for the first leakage current of the substrate of the first transistor module. The first compensation leakage current is equal to the first leakage current. The fourth compensation branch is used to generate a second compensation leakage current, which is used to compensate for the second leakage current of the substrate of the second transistor module. The second compensation leakage current is equal to the second leakage current.

2. The bandgap reference circuit according to claim 1, characterized in that, The first transistor module includes a first transistor, the base of the first transistor serving as the first terminal of the first transistor module for receiving the reference voltage, the collector of the first transistor serving as the second terminal of the first transistor module for electrical connection with the power supply, the emitter of the first transistor serving as the third terminal of the first transistor module for electrical connection with the first terminal of the first resistor module, and the substrate of the first transistor serving as the fourth terminal of the first transistor module.

3. The bandgap reference circuit according to claim 2, characterized in that, The second transistor module includes a second transistor, the base of which serves as the first terminal of the second transistor module for receiving the reference voltage, the collector of which serves as the second terminal of the second transistor module for electrical connection to the power supply, the emitter of which serves as the third terminal of the second transistor module and is electrically connected to the second terminal of the first resistor module and the first terminal of the second resistor module, respectively, and the substrate of which serves as the fourth terminal of the second transistor module.

4. The bandgap reference circuit according to claim 1, characterized in that, The first resistor module includes a first resistor, the first end of the first resistor serves as the first end of the first resistor module and is electrically connected to the third end of the first transistor module, and the second end of the first resistor serves as the second end of the first resistor module and is electrically connected to the third end of the second transistor module and the first end of the second resistor module, respectively.

5. The bandgap reference circuit according to claim 1, characterized in that, The second resistor module includes a second resistor. The first end of the second resistor serves as the first end of the second resistor module and is electrically connected to the second end of the first resistor module and the third end of the second transistor, respectively. The second end of the second resistor serves as the second end of the second resistor module and is grounded.

6. A current compensation method, applied to the bandgap reference circuit of claim 3, characterized in that, The current compensation method includes: A first compensation current is generated through a first compensation branch, which is a branch between the third terminal of the first transistor module and ground. The first compensation current is used to compensate for the first current flowing from the first terminal of the first transistor module to the third terminal of the first transistor module. A second compensation current is generated through a second compensation branch, which is the branch between the third terminal of the second transistor module and ground. The second compensation current is used to compensate for the second current flowing from the first terminal of the second transistor module to the third terminal of the second transistor module.

7. The current compensation method according to claim 6, characterized in that, The current compensation method further includes: A first compensation leakage current is generated through a third compensation branch, which is a branch between the power supply and the second terminal of the first transistor module. The first compensation leakage current is used to compensate for the first leakage current at the fourth terminal of the first transistor module. The first compensation leakage current is equal to the first leakage current. A second compensation leakage current is generated through a fourth compensation branch, which is the branch between the power supply and the second terminal of the second transistor module. The second compensation leakage current is used to compensate for the second leakage current at the fourth terminal of the second transistor module, and the second compensation leakage current is equal to the second leakage current.

8. The current compensation method according to claim 7, characterized in that, The current compensation method further includes: The first current, the second current, the first leakage current, and the second leakage current are collected by the sampling unit; Based on the first current, the second current, the first leakage current, and the second leakage current, determine the corresponding first compensation current, second compensation current, first compensation leakage current, and second compensation leakage current.

9. A reference power supply, characterized in that, Includes the bandgap reference circuit as described in any one of claims 1-5.

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