Curvature compensation band-gap reference voltage source and vehicle gauge level chip

Abstract

The invention provides a curvature compensation band-gap reference voltage source and a vehicle gauge level chip. The curvature compensation band-gap reference voltage source comprises a band-gap reference core circuit, a trimming circuit and a curvature compensation circuit. Due to the fact that an operational amplifier in the band-gap reference core circuit is a chopping operational amplifier, offset voltage of the operational amplifier changing along with temperature can be eliminated, curvature deviation of a first-order temperature compensation curve can be improved, and vertex deviation of the first-order temperature compensation curve can be improved through a target trimming code. Therefore, the band-gap reference core circuit can obtain an improved first-order temperature compensation curve, and insufficient compensation or excessive compensation caused by offset of the first-order temperature compensation curve is avoided. Therefore, the compensation effect of the curvature compensation band-gap reference voltage source is better, the temperature drift of the curvature compensation band-gap reference voltage source is lower, and mass production of vehicle gauge level chips with very low temperature drift is facilitated.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a curvature-compensated bandgap reference voltage source and an automotive-grade chip. Background Art

[0002] With the rapid development of new energy vehicles, the demand for automotive-grade chips is also increasing. The position and environment of automotive-grade chips in the vehicle body are different, and the requirements for their temperature tolerance are also different. The automotive standard ACE-Q100 divides the temperature tolerance of automotive-grade chips. Among them, the first level requires the operating temperature range of automotive-grade chips to be -40 to 125°C. Since the first-order compensated bandgap reference voltage source is the basic module of automotive-grade chips, the first-order compensated bandgap reference voltage source needs to provide a stable and unchanged reference voltage within the operating temperature range specified by the first level requirements to ensure the stable operation of automotive-grade chips. Since the first-order compensated bandgap reference voltage source cannot be used in applications with high requirements for temperature drift and linear adjustment rate. Therefore, the curvature compensated bandgap reference voltage source came into being.

[0003] In the related art, a curvature-compensated bandgap reference voltage source can generate a curvature-compensated current according to a first current that is positively correlated with temperature and a second current that is negatively correlated with temperature. Furthermore, the curvature-compensated bandgap reference voltage source uses the curvature-compensated current to perform high-order curvature compensation on a first-order temperature compensation curve of the curvature-compensated bandgap reference voltage source. Thus, the curvature-compensated bandgap reference voltage source has very low temperature drift.

[0004] However, the curvature-compensated bandgap reference voltage source in the related art is inevitably affected by the process and mismatch, causing the first-order temperature compensation curve to shift, resulting in poor temperature compensation effect of the curvature-compensated bandgap reference voltage source. As a result, the temperature drift of the curvature-compensated bandgap reference voltage source is relatively high, making it unable to meet the high-precision requirements of automotive-grade chips. Summary of the invention

[0005] The present application provides a curvature compensated bandgap reference voltage source and an automotive-grade chip, which can improve the offset of a first-order temperature compensation curve, so that the improved first-order temperature compensation curve is an ideal first-order temperature compensation curve, that is, the ideal first-order temperature compensation curve does not have curvature offset and vertex offset, so that when the improved first-order temperature compensation curve is subjected to curvature compensation, the temperature drift of the bandgap reference voltage source is low, which is conducive to the mass production of automotive-grade chips with very low temperature drift.

[0006] In a first aspect, the present application provides a curvature compensated bandgap reference voltage source, which includes: a bandgap reference core circuit, a trimming circuit and a curvature compensation circuit; wherein the operational amplifier in the bandgap reference core circuit is a chopper operational amplifier, and the chopper operational amplifier is used to improve the curvature offset of the first-order temperature compensation curve of the bandgap reference core circuit.

[0007] The first end of the bandgap reference core circuit is electrically connected to the first end of the curvature compensation circuit, the second end of the bandgap reference core circuit is electrically connected to the second end of the curvature compensation circuit, the third end of the bandgap reference core circuit is electrically connected to the third end of the curvature compensation circuit, the first end of the trimming circuit is electrically connected to the output end of the bandgap reference core circuit, and the second end of the trimming circuit is electrically connected to the adjustable resistor in the bandgap reference core circuit.

[0008] The trimming circuit is used to obtain a first output voltage of the bandgap reference core circuit at a first preset temperature, and to obtain a second output voltage of the bandgap reference core circuit at a second preset temperature, wherein the second preset temperature is higher than the first preset temperature; and to obtain a target trimming code based on the first output voltage, the second output voltage and an initial trimming code, wherein the target trimming code is used to improve the vertex offset of the first-order temperature compensation curve to obtain an improved first-order temperature compensation curve.

[0009] The curvature compensation circuit is used to obtain a negative temperature coefficient current and a positive temperature coefficient current from the bandgap reference core circuit, and generate a curvature compensation current based on the negative temperature coefficient current and the positive temperature coefficient current, and after the trimming circuit obtains the target trimming code, transmits the curvature compensation current to the bandgap reference core circuit, and the curvature compensation current is used to perform high-order curvature compensation on the first-order compensation reference voltage on the improved first-order temperature compensation curve.

[0010] The bandgap reference core circuit is used to reduce the temperature drift of the first-order compensation reference voltage in the improved first-order temperature compensation curve according to the curvature compensation current, so as to output a reference voltage with a zero temperature coefficient.

[0011] Through the curvature-compensated bandgap reference voltage source provided in the first aspect, the trimming circuit can obtain the first output voltage of the bandgap reference core circuit at a first preset temperature, and obtain the second output voltage of the bandgap reference core circuit at a second preset temperature, the second preset temperature being higher than the first preset temperature, and obtain the target trimming code according to the first output voltage, the second output voltage and the initial trimming code. The curvature compensation circuit can obtain the negative temperature coefficient current and the positive temperature coefficient current from the bandgap reference core circuit, and generate the curvature compensation current according to the negative temperature coefficient current and the positive temperature coefficient current, and after the trimming circuit obtains the target trimming code, the curvature compensation current used for performing high-order curvature compensation on the first-order compensation reference voltage on the improved first-order temperature compensation curve is transmitted to the bandgap reference core circuit. In this way, the bandgap reference core circuit can reduce the temperature drift of the first-order compensation reference voltage on the improved first-order temperature compensation curve according to the curvature compensation current, so that the bandgap reference core circuit outputs a reference voltage with a zero temperature coefficient. Since the operational amplifier in the bandgap reference core circuit is a chopper operational amplifier, the offset voltage of the operational amplifier that changes with temperature can be eliminated, so that the curvature offset of the first-order temperature compensation curve can be improved, and the target adjustment code can improve the vertex offset of the first-order temperature compensation curve. Therefore, the bandgap reference core circuit can obtain an improved first-order temperature compensation curve to avoid under-compensation or over-compensation caused by the offset of the first-order temperature compensation curve. As a result, the compensation effect of the curvature-compensated bandgap reference voltage source is better, and the temperature drift of the curvature-compensated bandgap reference voltage source is lower, which is conducive to the mass production of automotive-grade chips with very low temperature drift.

[0012] In a possible design, the initial trimming code includes a plurality of first trimming codes, where the first trimming codes are used to configure the resistance value of the adjustable resistor.

[0013] The trimming circuit is specifically used to determine the resistance value of the adjustable resistor corresponding to each of the first trimming codes, obtain the resistance values ​​of multiple adjustable resistors, and obtain the first output voltage and the second output voltage corresponding to the resistance value of each of the adjustable resistors.

[0014] The trimming circuit is further specifically used to determine the voltage difference between each of the first output voltage and the second output voltage, determine the smallest voltage difference among multiple voltage differences as the target voltage difference, and determine the first trimming code corresponding to the target voltage difference as the target trimming code.

[0015] In one possible design, the trimming circuit is further used to adjust the resistance or voltage of an output resistor in the bandgap reference core circuit after the bandgap reference core circuit outputs a reference voltage with a zero temperature coefficient, so that the reference voltage becomes a target reference voltage.

[0016] In one possible design, the bandgap reference core circuit includes: a positive temperature coefficient current generating circuit, a negative temperature coefficient current generating circuit and an output resistor, wherein the operational amplifier in the positive temperature coefficient current generating circuit and / or the negative temperature coefficient current generating circuit is the chopper operational amplifier.

[0017] The power supply end of the negative temperature coefficient current generating circuit is electrically connected to the power supply end of the positive temperature coefficient current generating circuit, the output end of the positive temperature coefficient current generating circuit is electrically connected to the first end of the output resistor, the output end of the negative temperature coefficient current generating circuit and the first end of the adjustment circuit are both electrically connected between the output end of the positive temperature coefficient current generating circuit and the first end of the output resistor, the first end of the curvature compensation circuit is electrically connected to the first end of the negative temperature coefficient current generating circuit, the second end of the negative temperature coefficient current generating circuit is electrically connected to the second end of the positive temperature coefficient current generating circuit, the second end of the curvature compensation circuit is electrically connected to the first end of the positive temperature coefficient current generating circuit, the third end of the curvature compensation circuit is electrically connected to the second end of the output resistor, the second end of the adjustment circuit is electrically connected to the first resistor in the negative temperature coefficient current generating circuit or the second resistor in the positive temperature coefficient current generating circuit, and the first resistor or the second resistor is the adjustable resistor.

[0018] The negative temperature coefficient current generating circuit is used to generate the negative temperature coefficient current and transmit the negative temperature coefficient current to the output resistor.

[0019] The positive temperature coefficient current generating circuit is used to generate the positive temperature coefficient current and transmit the positive temperature coefficient current to the output resistor.

[0020] The output resistor is used to obtain the curvature compensation current from the curvature compensation circuit, and generate the reference voltage under the action of the negative temperature coefficient current, the positive temperature coefficient current and the curvature compensation current.

[0021] In a possible design, the negative temperature coefficient current generating circuit includes: a first operational amplifier, a first transistor, a second transistor and the first resistor.

[0022] The first end of the first transistor and the first end of the second transistor are both electrically connected to the power supply end of the positive temperature coefficient current generating circuit, the control end of the first transistor is electrically connected to the control end of the second transistor, the second end of the first transistor is electrically connected to the first end of the first resistor, the second end of the second transistor is electrically connected between the output end of the positive temperature coefficient current generating circuit and the first end of the output resistor, the first input end of the first operational amplifier is electrically connected to the second end of the positive temperature coefficient current generating circuit, the second input end of the first operational amplifier is electrically connected between the second end of the first transistor and the first end of the first resistor, the output end of the first operational amplifier and the first end of the curvature compensation circuit are both electrically connected between the control end of the first transistor and the control end of the second transistor, and the second end of the first resistor is grounded.

[0023] In a possible design, the positive temperature coefficient current generating circuit includes: a second operational amplifier, a third transistor, a fourth transistor, a fifth transistor, a first triode, a second triode and the second resistor.

[0024] The first end of the third transistor, the first end of the fourth transistor and the first end of the fifth transistor are all electrically connected to the power supply end of the negative temperature coefficient current generating circuit, the control end of the third transistor is electrically connected to the control end of the fourth transistor and the control end of the fifth transistor respectively, the second end of the third transistor is electrically connected to the first end of the first triode, the second end of the fourth transistor is electrically connected to the first end of the second resistor, the second end of the second resistor is electrically connected to the first end of the second triode, the first input end of the second operational amplifier and the second end of the negative temperature coefficient current generating circuit are both electrically connected to the second end of the third transistor and the first triode. The second input terminal of the second operational amplifier is electrically connected between the second terminal of the fourth transistor and the first terminal of the second resistor, the output terminal of the second operational amplifier and the second terminal of the curvature compensation circuit are both electrically connected between the control terminal of the third transistor and the control terminal of the fourth transistor, the second terminal of the fifth transistor is electrically connected to the first terminal of the output resistor, the output terminal of the negative temperature coefficient current generating circuit is electrically connected between the second terminal of the fifth transistor and the first terminal of the output resistor, and the second terminal of the first triode, the control terminal of the first triode, the second terminal of the second triode and the control terminal of the second triode are all grounded.

[0025] In one possible design, the curvature compensation circuit includes: at least one first current mirror circuit and at least one second current mirror circuit.

[0026] The first end of the first current mirror circuit and the first end of the second current mirror circuit are both electrically connected to the first end of the negative temperature coefficient current generating circuit, the second end of the first current mirror circuit and the second end of the second current mirror circuit are both electrically connected to the first end of the positive temperature coefficient current generating circuit, and the third end of the first current mirror circuit and the third end of the second current mirror circuit are both electrically connected to the second end of the output resistor.

[0027] The first current mirror circuit is used to mirror the negative temperature coefficient current to obtain a mirrored negative temperature coefficient current, and to mirror the positive temperature coefficient current to obtain a mirrored positive temperature coefficient current, and to use the current difference between the mirrored negative temperature coefficient current and the mirrored positive temperature coefficient current as a first curvature compensation current, and the first curvature compensation current is used as a curvature compensation current in a first temperature range.

[0028] The second current mirror circuit is used to mirror the negative temperature coefficient current to obtain a mirrored negative temperature coefficient current, and to mirror the positive temperature coefficient current to obtain a mirrored positive temperature coefficient current, and to use the current difference between the mirrored negative temperature coefficient current and the mirrored positive temperature coefficient current as a second curvature compensation current, and the second curvature compensation current is used as a curvature compensation current in a second temperature range, the temperature in the second temperature range is greater than the temperature in the first temperature range, and the curvature compensation current is the current difference between the first curvature compensation current and the second curvature compensation current.

[0029] In one possible design, the curvature-compensated bandgap reference voltage source further includes: a low-pass filter circuit and a pre-stabilization circuit.

[0030] The input end of the low-pass filter circuit is electrically connected to the output end of the bandgap reference core circuit, the output end of the low-pass filter circuit is electrically connected to the input end of the pre-voltage regulator circuit, the power supply end of the pre-voltage regulator circuit is used to access the power supply voltage, and the output end of the pre-voltage regulator circuit is electrically connected to the power supply end of the bandgap reference core circuit.

[0031] The low-pass filter circuit is used to obtain the reference voltage from the bandgap reference core circuit, filter the reference voltage to obtain a filtered reference voltage, and transmit the filtered reference voltage to the pre-stabilization circuit.

[0032] The pre-stabilization circuit is used to output a first voltage proportional to the filtered reference voltage and transmit the first voltage to the bandgap reference core circuit. The first voltage is used to suppress changes in the power supply voltage to reduce the linear adjustment rate of the curvature compensation bandgap reference voltage source.

[0033] In one possible design, the pre-regulator circuit includes: a first error amplifier, a sixth transistor, a third resistor, and a fourth resistor.

[0034] The first end of the sixth transistor is used to access the power supply voltage, the second end of the first transistor is electrically connected to the first end of the third resistor, the second end of the third resistor is electrically connected to the first end of the fourth resistor, the output end of the first error amplifier is electrically connected to the control end of the sixth transistor, the first input end of the first error amplifier is electrically connected to the output end of the low-pass filter circuit, the second input end of the first error amplifier is electrically connected between the second end of the third resistor and the first end of the fourth resistor, and the second end of the fourth resistor is grounded.

[0035] In a possible design, the curvature-compensated bandgap reference voltage source further includes: a low voltage dropout linear voltage regulator circuit.

[0036] The input end of the low voltage difference linear voltage regulator circuit is electrically connected between the output end of the low-pass filter circuit and the input end of the pre-voltage regulator circuit, and the output end of the low voltage difference linear voltage regulator circuit is used to output a reference voltage with driving strength.

[0037] The low voltage difference linear voltage regulator circuit is used to enhance the driving strength of the filtered reference voltage so that the curvature compensation bandgap reference voltage source has load carrying capacity.

[0038] In one possible design, the low voltage difference linear voltage regulator circuit includes: a second error amplifier, a seventh transistor and a fifth resistor.

[0039] The first input terminal of the second error amplifier is electrically connected between the output terminal of the low-pass filter circuit and the input terminal of the pre-voltage regulator circuit, the output terminal of the second error amplifier is electrically connected to the control terminal of the seventh transistor, the first terminal of the seventh transistor is used to access the power supply voltage, the second terminal of the seventh transistor is electrically connected to the first terminal of the fifth resistor, the second input terminal of the second error amplifier is electrically connected between the second terminal of the seventh transistor and the first terminal of the fifth resistor, and the second terminal of the fifth resistor is grounded.

[0040] In a second aspect, the present application provides an automotive-grade chip, comprising: the curvature-compensated bandgap reference voltage source in the above-mentioned first aspect and each possible design of the above-mentioned first aspect.

[0041] The beneficial effects of the automotive-grade chip provided in the above-mentioned second aspect and each possible design of the above-mentioned second aspect can be referred to the beneficial effects brought about by the above-mentioned first aspect and each possible implementation method of the first aspect, and will not be repeated here.

[0042] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 It is a structural schematic diagram of a curvature compensation bandgap reference voltage source in the related art;

[0045] Figure 2 A schematic diagram of an ideal compensation effect of a curvature compensation bandgap reference voltage source in the related art;

[0046] Figure 3 A schematic diagram of the actual compensation effect of a curvature compensation bandgap reference voltage source in the related art;

[0047] Figure 4 A schematic diagram of the structure of a curvature-compensated bandgap reference voltage source provided in one embodiment of the present application;

[0048] Figure 5 A schematic diagram of the working process of a trimming circuit in a curvature-compensated bandgap reference voltage source provided in one embodiment of the present application;

[0049] Figure 6 A schematic structural diagram of another curvature-compensated bandgap reference voltage source provided in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In this application, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c alone can represent: a, b, c, a and b, a and c, or a, b, and c, where a, b, and c can be single or multiple. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0051] The directions or positional relationships indicated by terms such as "center", "longitudinal", "lateral", "up", "down", "left", "right", "front", and "back" are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present application and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0052] The terms "connected" and "connected" should be understood in a broad sense. For example, the "connected" or "connected" of a circuit structure can refer to not only physical connection, but also electrical connection or signal connection. For example, it can be directly connected, that is, physically connected, or indirectly connected through at least one intermediate element, as long as the circuit is connected, or it can be the internal connection of two elements; signal connection can refer to signal connection through a circuit or through a media medium, such as radio waves. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0053] As the basic module of automotive-grade chips, the bandgap reference voltage source needs to provide a stable reference voltage within the operating temperature range specified by the first-level requirements to ensure the stable operation of automotive-grade chips. Especially for battery detection chip systems, the reference voltage provided by the bandgap reference voltage source needs to have a low temperature drift within the operating temperature range of the battery detection chip system.

[0054] Among them, automotive-grade chips refer to chips whose technical standards meet automotive standards and can be used for automobile control.

[0055] In addition, the power supply voltage for automotive-grade chips is directly provided by the battery pack. Although the power supply voltage can reduce fluctuations after passing through a DC-DC converter, for applications with high-precision requirements, the fluctuations in the power supply voltage after passing through a DC-DC converter are still large.

[0056] In summary, the research on bandgap reference voltage sources with low temperature drift and low linear adjustment rate is of great significance to automotive-grade chips.

[0057] Bandgap reference voltage sources usually include: transistors and feedback loops. Since the temperature drift is limited by the nonlinearity of the voltage difference VBE between the base and emitter of the transistor, and the sensitivity to the power supply voltage is limited by the gain of the feedback loop, the bandgap reference voltage source cannot be used in applications that have high requirements for temperature drift and linear regulation. Therefore, the curvature compensated bandgap reference voltage source came into being.

[0058] Reference Figure 1 , Figure 1 is a schematic diagram of the structure of a curvature compensation bandgap reference voltage source in the related art, Figure 2 Shows Figure 1 Schematic diagram of the ideal compensation effect of the curvature compensation bandgap reference voltage source. Figure 1 As shown, the curvature compensation bandgap reference voltage source in the related art may include: a bandgap reference core module and a curvature compensation module. The curvature compensation module obtains voltages VC1 and VP1 from the bandgap reference core module, so that the curvature compensation module can mirror a first current that is positively correlated to temperature (proportional to absolute temperature, PTAT) and a second current that is negatively correlated to temperature (complementary to absolute temperature, CTAT). In this way, the curvature compensation module can generate a curvature compensation current based on the first current and the second current. Furthermore, the curvature compensation module transmits the curvature compensation current to the bandgap reference core module, so that the bandgap reference core module can obtain the curvature compensation current as shown in FIG. Figure 2 The compensation voltage VCOMP1 is shown in b. In this way, the bandgap reference core module can use the compensation voltage VCOMP1 to Figure 2 The first-order temperature compensation curve shown in a is used for high-order curvature compensation to obtain Figure 2 The reference voltage VREF1 shown in c in FIG. Therefore, the curvature-compensated bandgap reference voltage source can output a reference voltage VREF1 with a lower temperature coefficient.

[0059] Reference Figure 3 , Figure 3 Shows Figure 1 Schematic diagram of the actual compensation effect of the curvature compensation bandgap reference voltage source. Figure 3As shown in Figure 2, the curvature compensation bandgap reference voltage source is inevitably affected by the process and mismatch, which causes the first-order temperature compensation curve to be as follows: Figure 3 The vertex shown in d is to the left, as shown in Figure 3 The vertex shown in e is to the right, as shown in Figure 3 The curvature shown in f becomes smaller and Figure 3 The curvature shown in g in the figure becomes larger and other offsets of varying degrees. Furthermore, because the effect of curvature compensation is strongly correlated with the first-order temperature compensation curve, under-compensation or over-compensation occurs in both the low temperature range TL and the high temperature range TH. As a result, the temperature compensation effect of the curvature-compensated bandgap reference voltage source is poor, resulting in a high temperature drift of the curvature-compensated bandgap reference voltage source, which makes the curvature-compensated bandgap reference voltage source unable to meet the high-precision requirements of automotive-grade chips.

[0060] In order to solve the above technical problems, the present application provides a curvature compensated bandgap reference voltage source and an automotive-grade chip.

[0061] In this application, automotive-grade chips are generally used in various electronic systems of automobiles, which may include but are not limited to: engine control, body control, and infotainment systems.

[0062] The curvature compensation bandgap reference voltage source may be a chip or a circuit module.

[0063] Reference Figure 4 , Figure 4 This is a schematic diagram of the structure of a curvature compensation bandgap reference voltage source provided by an embodiment of the present application. Figure 4 As shown, the curvature compensated bandgap reference voltage source 1000 may include: a bandgap reference core circuit 100 , a trimming circuit 200 and a curvature compensation circuit 300 .

[0064] The bandgap reference core circuit 100 , the trimming circuit 200 and the curvature compensation circuit 300 may be arranged separately or integratedly.

[0065] The operational amplifier in the bandgap reference core circuit 100 is a chopper operational amplifier. In this way, the offset voltage of the operational amplifier that changes with temperature can be eliminated, so that the curvature offset of the first-order temperature compensation curve of the bandgap reference core circuit 100 can be improved. Therefore, under-compensation or over-compensation caused by the curvature offset of the first-order temperature compensation curve can be avoided, so as to improve the first-order compensation effect of the curvature-compensated bandgap reference voltage source 1000.

[0066] The chopper operational amplifier is used to improve the curvature offset of the first-order temperature compensation curve of the bandgap reference core circuit 100 .

[0067] A first end of the bandgap reference core circuit 100 is electrically connected to a first end of the curvature compensation circuit 300, a second end of the bandgap reference core circuit 100 is electrically connected to a second end of the curvature compensation circuit 300, a third end of the bandgap reference core circuit 100 is electrically connected to a third end of the curvature compensation circuit 300, a first end of the trimming circuit 200 is electrically connected to an output end of the bandgap reference core circuit 100, and a second end of the trimming circuit 200 is electrically connected to an adjustable resistor in the bandgap reference core circuit 100.

[0068] The trimming circuit 200 can obtain the first output voltage of the bandgap reference core circuit 100 at the first preset temperature, and obtain the second output voltage of the bandgap reference core circuit 100 at the second preset temperature. In addition, the trimming circuit 200 can obtain the target trimming code according to the first output voltage, the second output voltage and the initial trimming code.

[0069] The second preset temperature is higher than the first preset temperature, and the first preset temperature and the second preset temperature are located on both sides of the symmetry axis of the first-order temperature compensation curve. The first preset temperature is, for example, 20°C, and the second preset temperature is, for example, 60°C.

[0070] Among them, since the target adjustment code can determine the target resistance of the adjustable resistor. Therefore, the vertex offset of the first-order temperature compensation curve can be improved by the target adjustment code, so that the vertex of the improved first-order temperature compensation curve is located on the symmetry axis of the first-order temperature compensation curve, and insufficient compensation or overcompensation caused by the vertex offset of the first-order temperature compensation curve can be avoided. In this way, after the curvature offset of the first-order temperature compensation curve and the vertex offset of the first-order temperature compensation curve are improved, the bandgap reference core circuit 100 can obtain an improved first-order temperature compensation curve, wherein the improved first-order temperature compensation curve is the best first-order temperature compensation curve of the bandgap reference core circuit 100, so that the first-order compensation effect of the curvature compensated bandgap reference voltage source 1000 is better.

[0071] The curvature compensation circuit 300 can obtain the negative temperature coefficient current ICTAT and the positive temperature coefficient current IPTAT from the bandgap reference core circuit 100. Furthermore, the curvature compensation circuit 300 can generate the curvature compensation current ICOMP2 according to the negative temperature coefficient current ICTAT and the positive temperature coefficient current IPTAT, and after the trimming circuit 200 improves the vertex offset of the first-order temperature compensation curve, the curvature compensation current ICOMP2 is transmitted to the bandgap reference core circuit 100, so that the bandgap reference core circuit 100 can obtain the curvature compensation current ICOMP2.

[0072] The curvature compensation current ICOMP2 is used to perform high-order curvature compensation on the first-order compensation reference voltage on the improved first-order temperature compensation curve.

[0073] The bandgap reference core circuit can perform high-order curvature compensation on the first-order compensation reference voltage on the improved first-order temperature compensation curve according to the curvature compensation current ICOMP2, so as to reduce the temperature drift of the first-order compensation reference voltage on the improved first-order temperature compensation curve, so that the bandgap reference core circuit can output a reference voltage with a zero temperature coefficient. Thus, the curvature-compensated bandgap reference voltage source 1000 can output a reference voltage with a zero temperature coefficient.

[0074] The curvature-compensated bandgap reference voltage source and automotive-grade chip provided by the present application, the trimming circuit can obtain the first output voltage of the bandgap reference core circuit at the first preset temperature, and obtain the second output voltage of the bandgap reference core circuit at the second preset temperature, the second preset temperature is higher than the first preset temperature, and obtain the target trimming code according to the first output voltage, the second output voltage and the initial trimming code. The curvature compensation circuit can obtain the negative temperature coefficient current and the positive temperature coefficient current from the bandgap reference core circuit, and generate the curvature compensation current according to the negative temperature coefficient current and the positive temperature coefficient current, and after the trimming circuit obtains the target trimming code, the curvature compensation current for high-order curvature compensation of the first-order compensation reference voltage on the improved first-order temperature compensation curve is transmitted to the bandgap reference core circuit. In this way, the bandgap reference core circuit can reduce the temperature drift of the first-order compensation reference voltage on the improved first-order temperature compensation curve according to the curvature compensation current, so that the bandgap reference core circuit outputs a reference voltage with a zero temperature coefficient. Since the operational amplifier in the bandgap reference core circuit is a chopper operational amplifier, the offset voltage of the operational amplifier that changes with temperature can be eliminated, so that the curvature offset of the first-order temperature compensation curve can be improved, and the target adjustment code can improve the vertex offset of the first-order temperature compensation curve. Therefore, the bandgap reference core circuit can obtain an improved first-order temperature compensation curve to avoid the offset of the first-order temperature compensation curve leading to insufficient or overcompensation. As a result, the compensation effect of the curvature compensated bandgap reference voltage source is better, and the temperature drift of the curvature compensated bandgap reference voltage source is lower, which is conducive to the mass production of automotive-grade chips with very low temperature drift.

[0075] Reference Figure 5 , Figure 5 Shows Figure 4 The schematic diagram of the working process of the adjustment circuit. Figure 5 As shown, the trimming circuit 200 can determine the resistance value of the adjustable resistor corresponding to each first trimming code to obtain the resistance values ​​of multiple adjustable resistors. In addition, the trimming circuit 200 can obtain the first output voltage and the second output voltage corresponding to the resistance value of each adjustable resistor.

[0076] The initial trimming code includes a plurality of first trimming codes, and the first trimming codes are used to configure the resistance value of the adjustable resistor.

[0077] The trimming circuit 200 determines the voltage difference between each first output voltage and the second output voltage, determines the smallest voltage difference among the multiple voltage differences as the target voltage difference, and determines the first trimming code corresponding to the target voltage difference as the target trimming code, so that the trimming circuit 200 can improve the vertex offset of the first-order temperature compensation curve.

[0078] After the bandgap reference core circuit 100 outputs a reference voltage with a zero temperature coefficient, the trimming circuit 200 can adjust the resistance or voltage of the output resistor 130 in the bandgap reference core circuit 100 to make the reference voltage become a target reference voltage.

[0079] Specifically, the trimming circuit 200 can change the resistance of the output resistor 130 in a similar manner to changing the resistance of the adjustable resistor by the first trimming code, so that the reference voltage becomes the target reference voltage. Alternatively, the trimming circuit 200 can determine a certain reference voltage corresponding to the output resistor 130 as the target reference voltage.

[0080] Based on the description of the above embodiment, a possible implementation of the bandgap reference core circuit 100 is exemplified. Figure 4 As shown, the bandgap reference core circuit 100 may include a positive temperature coefficient current generating circuit 120 , a negative temperature coefficient current generating circuit 110 and an output resistor 130 .

[0081] The power supply terminal of the negative temperature coefficient current generating circuit 110 is electrically connected to the power supply terminal of the positive temperature coefficient current generating circuit 120, the output terminal of the positive temperature coefficient current generating circuit 120 is electrically connected to the first terminal of the output resistor 130, the output terminal of the negative temperature coefficient current generating circuit 110 and the first terminal of the adjustment circuit 200 are both electrically connected between the output terminal of the positive temperature coefficient current generating circuit 120 and the first terminal of the output resistor 130, the first terminal of the curvature compensation circuit 300 is electrically connected to the first terminal of the negative temperature coefficient current generating circuit 110, and the negative temperature coefficient current generating circuit 110 is electrically connected to the first terminal of the negative temperature coefficient current generating circuit 110. The second end of the current generating circuit 110 is electrically connected to the second end of the positive temperature coefficient current generating circuit 120, the second end of the curvature compensation circuit 300 is electrically connected to the first end of the positive temperature coefficient current generating circuit 120, the third end of the curvature compensation circuit 300 is electrically connected to the second end of the output resistor 130, and the second end of the adjustment circuit 200 is electrically connected to the first resistor R1 in the negative temperature coefficient current generating circuit 110 or the second resistor R2 in the positive temperature coefficient current generating circuit 120, and the first resistor R1 or the second resistor R2 is an adjustable resistor.

[0082] The operational amplifier in the positive temperature coefficient current generating circuit 120 and / or the negative temperature coefficient current generating circuit 110 is a chopper operational amplifier. When any one of the operational amplifiers in the positive temperature coefficient current generating circuit 120 and the negative temperature coefficient current generating circuit 110 is a chopper operational amplifier, the offset voltage of one operational amplifier can be eliminated, so that the curvature of the improved first-order temperature compensation curve in the present application is closer to the curvature of the ideal first-order temperature compensation curve, so that the consistency of the first-order temperature compensation curves of different curvature compensation bandgap reference voltage sources is better than the first-order temperature compensation curves in the related art.

[0083] When the operational amplifiers in the positive temperature coefficient current generating circuit 120 and the negative temperature coefficient current generating circuit 110 are both chopper operational amplifiers, the offset voltage of the operational amplifier can be completely eliminated, so that the curvature of the improved first-order temperature compensation curve in the present application is the curvature of the ideal first-order temperature compensation curve, so that the consistency of the first-order temperature compensation curves of different curvature compensation bandgap reference voltage sources can be greatly better than the first-order temperature compensation curves in the related art.

[0084] Among them, the first end of the negative temperature coefficient current generating circuit 110 is the first end of the bandgap reference core circuit 100, the first end of the positive temperature coefficient current generating circuit 120 is the second end of the bandgap reference core circuit 100, the second end of the output resistor 130 is the third end of the bandgap reference core circuit 100, and the output end of the bandgap reference core circuit 100 is located between the output end of the positive temperature coefficient current generating circuit 120 and the first end of the output resistor 130.

[0085] Since the first resistor R1 or the second resistor R2 is an adjustable resistor, the trimming circuit 200 can adjust the resistance of the first resistor R1 or the resistance of the second resistor R2 to obtain a target trimming code.

[0086] The negative temperature coefficient current generating circuit 110 can generate a negative temperature coefficient current ICTAT and transmit the negative temperature coefficient current ICTAT to the output resistor 130 so that the output resistor 130 can obtain the negative temperature coefficient current ICTAT.

[0087] The positive temperature coefficient current generating circuit 120 can generate a positive temperature coefficient current IPTAT and transmit the positive temperature coefficient current IPTAT to the output resistor 130 so that the output resistor 130 can obtain the positive temperature coefficient current IPTAT.

[0088] The output resistor 130 can obtain the compensation current ICOMP2 from the curvature compensation circuit 300. Furthermore, the output resistor 130 can generate a reference voltage based on the negative temperature coefficient current ICTAT, the positive temperature coefficient current IPTAT and the compensation current ICOMP2. Thus, the bandgap reference core circuit 100 can generate a reference voltage.

[0089] In some examples, the output resistor 130 may include a sixth resistor R6 and a compensation resistor Rc.

[0090] The first end of the sixth resistor R6 is electrically connected to the output end of the positive temperature coefficient current generating circuit 120, the second end of the sixth resistor R6 is electrically connected to the first end of the compensation resistor Rc, the third end of the curvature compensation circuit 300 is electrically connected between the second end of the sixth resistor R6 and the first end of the compensation resistor Rc, and the second end of the compensation resistor Rc is grounded.

[0091] After the bandgap reference core circuit 100 outputs a reference voltage with a zero temperature coefficient, the trimming circuit 200 specifically adjusts the resistance or voltage of the sixth resistor R6 so that the reference voltage becomes a target reference voltage.

[0092] Based on the description of the above embodiment, a possible implementation of the negative temperature coefficient current generating circuit 110 is exemplified. Figure 4 As shown, the negative temperature coefficient current generating circuit 110 may include: a first operational amplifier A1, a first transistor M1, a second transistor M2 and a first resistor R1.

[0093] The first end of the first transistor M1 and the first end of the second transistor M2 are both electrically connected to the power supply end of the positive temperature coefficient current generating circuit 120, the control end of the first transistor M1 is electrically connected to the control end of the second transistor M2, the second end of the first transistor M1 is electrically connected to the first end of the first resistor R1, the second end of the second transistor M2 is electrically connected between the output end of the positive temperature coefficient current generating circuit 120 and the first end of the output resistor 130, the first input end of the first operational amplifier A1 is electrically connected to the second end of the positive temperature coefficient current generating circuit 120, the second input end of the first operational amplifier A1 is electrically connected between the second end of the first transistor M1 and the first end of the first resistor R1, the output end of the first operational amplifier A1 and the first end of the curvature compensation circuit 300 are both electrically connected between the control end of the first transistor M1 and the control end of the second transistor M2, and the second end of the first resistor R1 is grounded.

[0094] Among them, the first end of the first transistor M1 and the first end of the second transistor M2 are both power supply ends of the negative temperature coefficient current generating circuit 110, the first end of the negative temperature coefficient current generating circuit 110 is located between the control end of the first transistor M1 and the control end of the second transistor M2, the second end of the second transistor M2 is the output end of the negative temperature coefficient current generating circuit 110, and the first input end of the first operational amplifier A1 is the second end of the negative temperature coefficient current generating circuit 110.

[0095] Based on the description of the above embodiment, a possible implementation of the positive temperature coefficient current generating circuit 120 is exemplified. Figure 4 As shown, the positive temperature coefficient current generating circuit 120 may include: a second operational amplifier A2, a third transistor M3, a fourth transistor M4, a fifth transistor M5, a first triode Q1, a second triode Q2 and a second resistor R2.

[0096] The first end of the third transistor M3, the first end of the fourth transistor M4 and the first end of the fifth transistor M5 are all electrically connected to the power supply end of the negative temperature coefficient current generating circuit 110, the control end of the third transistor M3 is electrically connected to the control end of the fourth transistor M4 and the control end of the fifth transistor M5 respectively, the second end of the third transistor M3 is electrically connected to the first end of the first triode Q1, the second end of the fourth transistor M4 is electrically connected to the first end of the second resistor R2, the second end of the second resistor R2 is electrically connected to the first end of the second triode Q2, the first input end of the second operational amplifier A2 and the second end of the negative temperature coefficient current generating circuit 110 are both electrically connected to the second end of the third transistor M3 and the first triode Q 1, a second input terminal of the second operational amplifier A2 is electrically connected between the second terminal of the fourth transistor M4 and the first terminal of the second resistor R2, an output terminal of the second operational amplifier A2 and a second terminal of the curvature compensation circuit 300 are both electrically connected between the control terminal of the third transistor M3 and the control terminal of the fourth transistor M4, a second terminal of the fifth transistor M5 is electrically connected to the first terminal of the output resistor 130, an output terminal of the negative temperature coefficient current generating circuit 110 is electrically connected between the second terminal of the fifth transistor M5 and the first terminal of the output resistor 130, and a second terminal of the first triode Q1, a control terminal of the first triode Q1, a second terminal of the second triode Q2 and a control terminal of the second triode Q2 are all grounded.

[0097] Among them, the first end of the third transistor M3, the first end of the fourth transistor M4 and the first end of the fifth transistor M5 are all power supply ends of the positive temperature coefficient current generating circuit 120, the second end of the fifth transistor M5 is the output end of the positive temperature coefficient current generating circuit 120, the first end of the positive temperature coefficient current generating circuit 120 is located between the control end of the third transistor M3 and the control end of the fourth transistor M4, and the first input end of the second operational amplifier A2 is the second end of the positive temperature coefficient current generating circuit 120.

[0098] Based on the description of the above embodiment, a possible implementation of the curvature compensation circuit 300 is exemplified. Figure 4 As shown, the curvature compensation circuit 300 may include: at least one first current mirror circuit 320 and at least one second current mirror circuit 310 .

[0099] The first end of the first current mirror circuit 320 and the first end of the second current mirror circuit 310 are both electrically connected to the first end of the negative temperature coefficient current generating circuit 110, the second end of the first current mirror circuit 320 and the second end of the second current mirror circuit 310 are both electrically connected to the first end of the positive temperature coefficient current generating circuit 120, and the third end of the first current mirror circuit 320 and the third end of the second current mirror circuit 310 are both electrically connected to the second end of the output resistor 130.

[0100] Among them, the number of the first current mirror circuits 320 and the number of the second current mirror circuits 310 are the same. For example, when the number of the first current mirror circuits 320 is 3, the number of the second current mirror circuits 310 is also 3; for another example, when the number of the first current mirror circuits 320 is 5, the number of the second current mirror circuits 310 is also 5.

[0101] In addition, by adjusting the number of the first current mirror circuit 320 and the second current mirror circuit 310, the curvature compensation circuit 300 can transmit the segmented curvature compensation current ICOMP2 to the bandgap reference core circuit 100, so that the segmented curvature compensation current ICOMP2 can perform segmented high-order curvature compensation on the improved first-order temperature compensation curve. Thus, the curvature compensation bandgap reference voltage source outputs a reference voltage with a zero temperature coefficient.

[0102] Among them, the first end of the first current mirror circuit 320 and the first end of the second current mirror circuit 310 are both the first end of the curvature compensation circuit 300, the second end of the first current mirror circuit 320 and the second end of the second current mirror circuit 310 are both the second end of the curvature compensation circuit 300, and the third end of the first current mirror circuit 320 and the third end of the second current mirror circuit 310 are both the third end of the curvature compensation circuit 300.

[0103] In some examples, the first current mirror circuit 320 may include: a first P-type mirror transistor MP1, a second P-type mirror transistor MP2, a third P-type mirror transistor MP3, a fourth P-type mirror transistor MP4, a first N-type mirror transistor MN1, and a second N-type mirror transistor MN2.

[0104] The first end of the first P-type mirror tube MP1, the first end of the second P-type mirror tube MP2, the first end of the third P-type mirror tube MP3 and the first end of the fourth P-type mirror tube MP4 are all used to access the power supply voltage VDD, the control end of the second P-type mirror tube MP2 is electrically connected to the first end of the negative temperature coefficient current generating circuit 110, the second end of the second P-type mirror tube MP2 is electrically connected to the second end of the second N-type mirror tube MN2, the control end of the second N-type mirror tube MN2 and the control end of the first N-type mirror tube MN1 respectively, the second end of the first N-type mirror tube MN1 is electrically connected to the second end of the first P-type mirror tube MP1, the second end of the fourth P-type mirror tube MP4, the control end of the fourth P-type mirror tube MP4 and the control end of the third P-type mirror tube MP3 respectively, the second end of the third P-type mirror tube MP3 is electrically connected to the second end of the output resistor 130, the control end of the first P-type mirror tube MP1 is electrically connected to the first end of the positive temperature coefficient current generating circuit 120, and the first end of the first N-type mirror tube MN1 and the first end of the second N-type mirror tube MN2 are both grounded.

[0105] The positive temperature coefficient current IPTAT is mirrored from the positive temperature coefficient current generating circuit 120 through the first P-type mirror tube MP1, and the negative temperature coefficient current ICTAT is mirrored from the negative temperature coefficient current generating circuit 110 by the second P-type mirror tube MP2. In this way, the negative temperature coefficient current ICTAT is mirrored by the first N-type mirror tube MN1 and the second N-type mirror tube MN2, so that the current of the fourth P-type mirror tube MP4 is equal to the current difference of the negative temperature coefficient current ICTAT minus the positive temperature coefficient current IPTAT. Furthermore, as the temperature rises, the current of the fourth P-type mirror tube MP4 continues to decrease until the current of the first N-type mirror tube MN1 is less than the current of the first P-type mirror tube MP1, and the fourth P-type mirror tube MP4 is turned off, so that the current of the fourth P-type mirror tube MP4 drops to zero. Therefore, as the temperature rises, the current of the fourth P-type mirror tube MP4 remains at zero current, so that the first current mirror circuit 320 can generate a curvature compensation current in the first temperature range, that is, the first curvature compensation current IL1.

[0106] Thus, the first current mirror circuit 320 can mirror the negative temperature coefficient current ICTAT to obtain the mirrored negative temperature coefficient current ICTAT, and mirror the positive temperature coefficient current IPTAT to obtain the mirrored positive temperature coefficient current IPTAT. In addition, the first current mirror circuit 320 can use the current difference between the mirrored negative temperature coefficient current ICTAT and the mirrored positive temperature coefficient current IPTAT as the first compensation curvature current IL1.

[0107] The first curvature compensation current IL1 is used as the curvature compensation current in the first temperature range.

[0108] Similarly, the second current mirror circuit 310 can mirror the negative temperature coefficient current ICTAT to obtain the mirrored negative temperature coefficient current ICTAT, and mirror the positive temperature coefficient current IPTAT to obtain the mirrored positive temperature coefficient current IPTAT. In addition, the second current mirror circuit 310 can use the current difference between the mirrored negative temperature coefficient current ICTAT and the mirrored positive temperature coefficient current IPTAT as the second curvature compensation current IH1.

[0109] The second curvature compensation current IH1 is used as a curvature compensation current in a second temperature range, the temperature in the second temperature range is greater than the temperature in the first temperature range, and the curvature compensation current ICOMP2 is a current difference between the first curvature compensation current IL1 and the second curvature compensation current IH1.

[0110] By adjusting the ratio of the number of parallel connections of the first P-type mirror tube MP1 and the second P-type mirror tube MP2, the ratio of the current of the first P-type mirror tube MP1 to the positive temperature coefficient current IPTAT and the ratio of the current of the second P-type mirror tube MP2 to the negative temperature coefficient current ICTAT are changed. In this way, the current of the fourth P-type mirror tube MP4 is also changed, so that the trigger temperature threshold of the first compensation curvature current IL1 is adjusted.

[0111] Among them, by adjusting the ratio of the number of the third P-type mirror tube MP3 and the fourth P-type mirror tube MP4 connected in parallel, the ratio between the current of the third P-type mirror tube MP3 and the current of the fourth P-type mirror tube MP4 is changed, so that the magnitude of the first compensating curvature current IL1 is adjusted, that is, the slope of the curvature compensation current temperature curve is adjusted.

[0112] The working principle of adjusting the triggering temperature threshold and the magnitude of the second curvature compensation current IH1 is similar to that of the first compensation curvature current IL1 , and thus will not be elaborated herein.

[0113] Based on the description of the above embodiment, another possible implementation of the curvature compensation bandgap reference voltage source 1000 is exemplified. Figure 6 , Figure 6 A schematic diagram of the structure of another curvature compensation bandgap reference voltage source provided in an embodiment of the present application. Figure 6 As shown, the curvature-compensated bandgap reference voltage source 1000 may further include: a low-pass filter circuit 400 and a pre-stabilization circuit 500 .

[0114] The input end of the low-pass filter circuit 400 is electrically connected to the output end of the bandgap reference core circuit 100, the output end of the low-pass filter circuit 400 is electrically connected to the input end of the pre-stabilization circuit 500, the power supply end of the pre-stabilization circuit 500 is used to access the power supply voltage VDD, and the output end of the pre-stabilization circuit 500 is electrically connected to the power supply end of the bandgap reference core circuit 100.

[0115] The low-pass filter circuit 400 can obtain a reference voltage from the bandgap reference core circuit 100. In addition, the low-pass filter circuit 400 can filter the reference voltage so that the ripple voltage introduced when the operational amplifier is a chopper operational amplifier is eliminated. Thus, the low-pass filter circuit 400 can obtain the filtered reference voltage VOLF, and transmit the filtered reference voltage VOLF to the pre-regulator circuit 500, so that the pre-regulator circuit 500 can obtain the filtered reference voltage VOLF.

[0116] Figure 5 and Figure 6 , it is shown that the first operational amplifier A1 and the second operational amplifier A2 are both chopper operational amplifiers. When the first operational amplifier A1 is a chopper operational amplifier, the first chopper operational amplifier corresponding to the first operational amplifier A1 is represented by the number 111. When the second operational amplifier A2 is a chopper operational amplifier, the second chopper operational amplifier corresponding to the second operational amplifier A2 is represented by the number 121.

[0117] In some examples, the pre-regulator circuit 500 may include: a first error amplifier EA1 , a sixth transistor M6 , a third resistor R3 , and a fourth resistor R4 .

[0118] The first end of the sixth transistor M6 is used to access the power supply voltage VDD, the second end of the first transistor M1 is electrically connected to the first end of the third resistor R3, the second end of the third resistor R3 is electrically connected to the first end of the fourth resistor R4, the output end of the first error amplifier EA1 is electrically connected to the control end of the sixth transistor M6, the first input end of the first error amplifier EA1 is electrically connected to the output end of the low-pass filter circuit 400, the second input end of the first error amplifier EA1 is electrically connected between the second end of the third resistor R3 and the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is grounded.

[0119] By adjusting the resistance ratio between the third resistor R3 and the fourth resistor R4, the pre-regulator circuit 500 can output a first voltage VDDX proportional to the filtered reference voltage VOLF. In addition, the pre-regulator circuit 500 can transmit the first voltage VDDX to the bandgap reference core circuit 100 to reduce the linear regulation rate of the curvature-compensated bandgap reference voltage source 1000. Thus, the sensitivity of the bandgap reference core circuit 100 to the power supply voltage VDD is reduced, so that the curvature-compensated bandgap reference voltage source 1000 has an extremely low linear regulation rate.

[0120] The first voltage VDDX is used to suppress changes in the power supply voltage VDD.

[0121] The bandgap reference core circuit 100 itself also has an inhibitory effect on the change of the first voltage VDDX.

[0122] Based on the description of the above embodiment, another possible implementation of the curvature compensation bandgap reference voltage source 1000 is exemplified. Figure 6 As shown, the curvature-compensated bandgap reference voltage source 1000 may further include: a low voltage dropout linear voltage regulator circuit 600 .

[0123] The input end of the low voltage difference linear voltage regulator circuit 600 is electrically connected between the output end of the low pass filter circuit 400 and the input end of the pre-voltage regulator circuit 500 , and the output end of the low voltage difference linear voltage regulator circuit 600 is used to output a reference voltage with driving strength.

[0124] In some examples, the low voltage dropout linear regulator circuit 600 may include: a second error amplifier EA2 , a seventh transistor M7 , and a fifth resistor R5 .

[0125] The first input terminal of the second error amplifier EA2 is electrically connected between the output terminal of the low-pass filter circuit 400 and the input terminal of the pre-voltage regulator circuit 500, the output terminal of the second error amplifier EA2 is electrically connected to the control terminal of the seventh transistor M7, the first terminal of the seventh transistor M7 is used to access the power supply voltage VDD, the second terminal of the seventh transistor M7 is electrically connected to the first terminal of the fifth resistor R5, the second input terminal of the second error amplifier EA2 is electrically connected between the second terminal of the seventh transistor M7 and the first terminal of the fifth resistor R5, and the second terminal of the fifth resistor R5 is grounded.

[0126] The low voltage difference linear voltage regulator circuit 600 can enhance the driving strength of the filtered reference voltage VOLF, so that the curvature compensation bandgap reference voltage source 1000 has load carrying capability.

[0127] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto, and any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A curvature-compensated bandgap reference voltage source, characterized in that: include: A bandgap reference core circuit, a trimming circuit and a curvature compensation circuit; wherein the operational amplifier in the bandgap reference core circuit is a chopper operational amplifier, and the chopper operational amplifier is used to improve the curvature offset of the first-order temperature compensation curve of the bandgap reference core circuit; The first end of the bandgap reference core circuit is electrically connected to the first end of the curvature compensation circuit, the second end of the bandgap reference core circuit is electrically connected to the second end of the curvature compensation circuit, the third end of the bandgap reference core circuit is electrically connected to the third end of the curvature compensation circuit, the first end of the trimming circuit is electrically connected to the output end of the bandgap reference core circuit, and the second end of the trimming circuit is electrically connected to the adjustable resistor in the bandgap reference core circuit; The trimming circuit is used to obtain a first output voltage of the bandgap reference core circuit at a first preset temperature, and to obtain a second output voltage of the bandgap reference core circuit at a second preset temperature, wherein the second preset temperature is higher than the first preset temperature; and to obtain a target trimming code according to the first output voltage, the second output voltage and an initial trimming code, wherein the target trimming code is used to improve a vertex offset of the first-order temperature compensation curve to obtain an improved first-order temperature compensation curve; The curvature compensation circuit is used to obtain a negative temperature coefficient current and a positive temperature coefficient current from the bandgap reference core circuit, and generate a curvature compensation current according to the negative temperature coefficient current and the positive temperature coefficient current, and transmit the curvature compensation current to the bandgap reference core circuit after the trimming circuit obtains the target trimming code, wherein the curvature compensation current is used to perform high-order curvature compensation on the first-order compensation reference voltage on the improved first-order temperature compensation curve; The bandgap reference core circuit is used to reduce the temperature drift of the first-order compensation reference voltage on the improved first-order temperature compensation curve according to the curvature compensation current, so as to output a reference voltage with a zero temperature coefficient.

2. The curvature-compensated bandgap reference voltage source according to claim 1, characterized in that: The initial trimming code includes a plurality of first trimming codes, wherein the first trimming codes are used to configure the resistance value of the adjustable resistor; The trimming circuit is specifically used to determine the resistance value of the adjustable resistor corresponding to each of the first trimming codes, obtain the resistance values ​​of multiple adjustable resistors, and obtain the first output voltage and the second output voltage corresponding to the resistance value of each of the adjustable resistors; The trimming circuit is further specifically used to determine the voltage difference between each of the first output voltage and the second output voltage, determine the smallest voltage difference among multiple voltage differences as the target voltage difference, and determine the first trimming code corresponding to the target voltage difference as the target trimming code.

3. The curvature-compensated bandgap reference voltage source according to claim 2, characterized in that: The trimming circuit is further used to adjust the resistance or voltage of the output resistor in the bandgap reference core circuit after the bandgap reference core circuit outputs a reference voltage with a zero temperature coefficient, so that the reference voltage becomes a target reference voltage.

4. The curvature-compensated bandgap reference voltage source according to claim 2, characterized in that: The bandgap reference core circuit comprises: a positive temperature coefficient current generating circuit, a negative temperature coefficient current generating circuit and an output resistor, wherein the operational amplifier in the positive temperature coefficient current generating circuit and / or the negative temperature coefficient current generating circuit is the chopper operational amplifier; The power supply end of the negative temperature coefficient current generating circuit is electrically connected to the power supply end of the positive temperature coefficient current generating circuit, the output end of the positive temperature coefficient current generating circuit is electrically connected to the first end of the output resistor, the output end of the negative temperature coefficient current generating circuit and the first end of the trimming circuit are both electrically connected between the output end of the positive temperature coefficient current generating circuit and the first end of the output resistor, the first end of the curvature compensation circuit is electrically connected to the first end of the negative temperature coefficient current generating circuit, the second end of the negative temperature coefficient current generating circuit is electrically connected to the second end of the positive temperature coefficient current generating circuit, the second end of the curvature compensation circuit is electrically connected to the first end of the positive temperature coefficient current generating circuit, the third end of the curvature compensation circuit is electrically connected to the second end of the output resistor, the second end of the trimming circuit is electrically connected to the first resistor in the negative temperature coefficient current generating circuit or the second resistor in the positive temperature coefficient current generating circuit, and the first resistor or the second resistor is the adjustable resistor; The negative temperature coefficient current generating circuit is used to generate the negative temperature coefficient current and transmit the negative temperature coefficient current to the output resistor; The positive temperature coefficient current generating circuit is used to generate the positive temperature coefficient current and transmit the positive temperature coefficient current to the output resistor; The output resistor is used to obtain the curvature compensation current from the curvature compensation circuit, and generate the reference voltage under the action of the negative temperature coefficient current, the positive temperature coefficient current and the curvature compensation current.

5. The curvature-compensated bandgap reference voltage source according to claim 4, characterized in that: The negative temperature coefficient current generating circuit comprises: a first operational amplifier, a first transistor, a second transistor and the first resistor; The first end of the first transistor and the first end of the second transistor are both electrically connected to the power supply end of the positive temperature coefficient current generating circuit, the control end of the first transistor is electrically connected to the control end of the second transistor, the second end of the first transistor is electrically connected to the first end of the first resistor, the second end of the second transistor is electrically connected between the output end of the positive temperature coefficient current generating circuit and the first end of the output resistor, the first input end of the first operational amplifier is electrically connected to the second end of the positive temperature coefficient current generating circuit, the second input end of the first operational amplifier is electrically connected between the second end of the first transistor and the first end of the first resistor, the output end of the first operational amplifier and the first end of the curvature compensation circuit are both electrically connected between the control end of the first transistor and the control end of the second transistor, and the second end of the first resistor is grounded.

6. The curvature-compensated bandgap reference voltage source according to claim 4, characterized in that: The positive temperature coefficient current generating circuit comprises: a second operational amplifier, a third transistor, a fourth transistor, a fifth transistor, a first triode, a second triode and the second resistor; The first end of the third transistor, the first end of the fourth transistor and the first end of the fifth transistor are all electrically connected to the power supply end of the negative temperature coefficient current generating circuit, the control end of the third transistor is electrically connected to the control end of the fourth transistor and the control end of the fifth transistor respectively, the second end of the third transistor is electrically connected to the first end of the first triode, the second end of the fourth transistor is electrically connected to the first end of the second resistor, the second end of the second resistor is electrically connected to the first end of the second triode, the first input end of the second operational amplifier and the second end of the negative temperature coefficient current generating circuit are both electrically connected to the second end of the third transistor and the first triode. The second input terminal of the second operational amplifier is electrically connected between the second terminal of the fourth transistor and the first terminal of the second resistor, the output terminal of the second operational amplifier and the second terminal of the curvature compensation circuit are both electrically connected between the control terminal of the third transistor and the control terminal of the fourth transistor, the second terminal of the fifth transistor is electrically connected to the first terminal of the output resistor, the output terminal of the negative temperature coefficient current generating circuit is electrically connected between the second terminal of the fifth transistor and the first terminal of the output resistor, and the second terminal of the first triode, the control terminal of the first triode, the second terminal of the second triode and the control terminal of the second triode are all grounded.

7. The curvature-compensated bandgap reference voltage source according to claim 4, characterized in that: The curvature compensation circuit comprises: at least one first current mirror circuit and at least one second current mirror circuit; The first end of the first current mirror circuit and the first end of the second current mirror circuit are both electrically connected to the first end of the negative temperature coefficient current generating circuit, the second end of the first current mirror circuit and the second end of the second current mirror circuit are both electrically connected to the first end of the positive temperature coefficient current generating circuit, and the third end of the first current mirror circuit and the third end of the second current mirror circuit are both electrically connected to the second end of the output resistor; The first current mirror circuit is used for mirroring the negative temperature coefficient current to obtain a mirrored negative temperature coefficient current, and mirroring the positive temperature coefficient current to obtain a mirrored positive temperature coefficient current, and using the current difference between the mirrored negative temperature coefficient current and the mirrored positive temperature coefficient current as a first curvature compensation current, and the first curvature compensation current is used as a curvature compensation current in a first temperature range; The second current mirror circuit is used to mirror the negative temperature coefficient current to obtain a mirrored negative temperature coefficient current, and to mirror the positive temperature coefficient current to obtain a mirrored positive temperature coefficient current, and to use the current difference between the mirrored negative temperature coefficient current and the mirrored positive temperature coefficient current as a second curvature compensation current, and the second curvature compensation current is used as a curvature compensation current in a second temperature range, the temperature in the second temperature range is greater than the temperature in the first temperature range, and the curvature compensation current is the current difference between the first curvature compensation current and the second curvature compensation current.

8. The curvature-compensated bandgap reference voltage source according to any one of claims 1 to 7, characterized in that: The curvature compensation bandgap reference voltage source further includes: a low-pass filter circuit and a pre-stabilization circuit; The input end of the low-pass filter circuit is electrically connected to the output end of the bandgap reference core circuit, the output end of the low-pass filter circuit is electrically connected to the input end of the pre-stabilization circuit, the power supply end of the pre-stabilization circuit is used to access the power supply voltage, and the output end of the pre-stabilization circuit is electrically connected to the power supply end of the bandgap reference core circuit; The low-pass filter circuit is used to obtain the reference voltage from the bandgap reference core circuit, filter the reference voltage to obtain a filtered reference voltage, and transmit the filtered reference voltage to the pre-stabilization circuit; The pre-stabilization circuit is used to output a first voltage proportional to the filtered reference voltage and transmit the first voltage to the bandgap reference core circuit. The first voltage is used to suppress changes in the power supply voltage to reduce the linear adjustment rate of the curvature compensation bandgap reference voltage source.

9. The curvature-compensated bandgap reference voltage source according to claim 8, characterized in that: The pre-stabilization circuit comprises: a first error amplifier, a sixth transistor, a third resistor and a fourth resistor; The first end of the sixth transistor is used to access the power supply voltage, the second end of the first transistor is electrically connected to the first end of the third resistor, the second end of the third resistor is electrically connected to the first end of the fourth resistor, the output end of the first error amplifier is electrically connected to the control end of the sixth transistor, the first input end of the first error amplifier is electrically connected to the output end of the low-pass filter circuit, the second input end of the first error amplifier is electrically connected between the second end of the third resistor and the first end of the fourth resistor, and the second end of the fourth resistor is grounded.

10. The curvature-compensated bandgap reference voltage source according to claim 8, characterized in that: The curvature compensation bandgap reference voltage source further includes: a low voltage drop linear voltage stabilization circuit; The input end of the low voltage difference linear voltage regulator circuit is electrically connected between the output end of the low-pass filter circuit and the input end of the pre-voltage regulator circuit, and the output end of the low voltage difference linear voltage regulator circuit is used to output a reference voltage with driving strength; The low voltage difference linear voltage regulator circuit is used to enhance the driving strength of the filtered reference voltage so that the curvature compensation bandgap reference voltage source has load carrying capacity.

11. The curvature-compensated bandgap reference voltage source according to claim 10, characterized in that: The low voltage difference linear voltage stabilization circuit comprises: a second error amplifier, a seventh transistor and a fifth resistor; The first input terminal of the second error amplifier is electrically connected between the output terminal of the low-pass filter circuit and the input terminal of the pre-voltage regulator circuit, the output terminal of the second error amplifier is electrically connected to the control terminal of the seventh transistor, the first terminal of the seventh transistor is used to access the power supply voltage, the second terminal of the seventh transistor is electrically connected to the first terminal of the fifth resistor, the second input terminal of the second error amplifier is electrically connected between the second terminal of the seventh transistor and the first terminal of the fifth resistor, and the second terminal of the fifth resistor is grounded.

12. An automotive-grade chip, characterized in that: include: A curvature compensated bandgap reference voltage source as claimed in any one of claims 1 to 11.

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