Bandgap reference circuit, electronic device

Abstract

This disclosure relates to the field of integrated circuit technology, and more particularly to a bandgap reference circuit and electronic device. The circuit includes: a startup module for providing a startup current; a bandgap reference voltage source module connected to the startup module for receiving the startup current and a power supply voltage to generate an intermediate voltage, wherein the startup current is used to cause the bandgap reference voltage source module to leave a zero-degenerate state and enter a normal operating state; and a trimming module connected to the bandgap reference voltage source module for compensating the temperature coefficient of the bandgap reference voltage source module and generating a bandgap reference voltage based on the intermediate voltage. Embodiments of this disclosure compensate for the temperature coefficient of the bandgap reference voltage source module to achieve a lower temperature coefficient across the entire temperature range.

Description

Technical Field

[0001] This disclosure relates to the field of integrated circuit technology, and in particular to a bandgap reference circuit and electronic equipment. Background Technology

[0002] Voltage reference sources are crucial for most analog and mixed-signal applications, such as regulators, analog-to-digital converters (ADCs), and digital-to-analog converters (DACs). Bandgap voltage references (BGRs) are widely used due to their low temperature coefficient (TC) and high power supply rejection ratio (PSR). The key to achieving a low temperature coefficient in BGRs lies in using voltages with opposite temperature characteristics to cancel out the effects of temperature on the output voltage. This design ensures that the reference voltage remains relatively stable over a wide temperature range. A voltage that increases proportionally with temperature is typically called a positive temperature coefficient voltage (PTC). The voltage that decreases proportionally with temperature is called the negative temperature coefficient voltage. Then, for the voltage with the smaller slope (here, the PTAT voltage), multiply it by a temperature-independent coefficient. If the absolute values ​​of the slopes of these two voltages are equal at this point, then adding these two curves together will yield a temperature-independent voltage curve.

[0003] If only the first-order temperature coefficient is considered, an appropriate scaling factor can be selected. To compensate for the positive and negative temperature coefficients in order to realize a first-order bandgap reference voltage source, however, due to the influence of higher-order terms, the temperature coefficient of the first-order bandgap reference voltage source is relatively high, which will cause the bandgap voltage output by the bandgap voltage source to change significantly with temperature.

[0004] Therefore, how to achieve a lower temperature coefficient to improve the stability of the bandgap voltage output by the bandgap voltage source has become a major problem that urgently needs to be solved. Summary of the Invention

[0005] According to one aspect of this disclosure, a bandgap reference circuit is provided, the circuit comprising:

[0006] The startup module is used to provide the startup current;

[0007] A bandgap reference voltage source module is connected to the startup module and is used to receive the startup current and power supply voltage to generate an intermediate voltage. The startup current is used to enable the bandgap reference voltage source module to leave the zero degeneracy state and enter the normal operation state.

[0008] The adjustment module, connected to the bandgap reference voltage source module, is used to compensate for the temperature coefficient of the bandgap reference voltage source module and generate a bandgap reference voltage based on the intermediate voltage.

[0009] In one possible implementation, the startup module includes a zeroth transistor, a first transistor, and a second transistor, wherein,

[0010] The gate of the zeroth transistor is grounded, the source of the zeroth transistor is used to receive the power supply voltage, and the drain of the zeroth transistor is connected to the drain of the first transistor and the gate of the second transistor.

[0011] The gate of the first transistor is used to receive a start control signal.

[0012] The drain of the second transistor is used to receive the first bias voltage.

[0013] The source of the first transistor and the source of the second transistor are grounded.

[0014] In one possible implementation, the bandgap reference voltage source module includes a zero-th resistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, a zero-th transistor, a first transistor, a zero-th operational amplifier, and a first operational amplifier, wherein...

[0015] The sources of the third transistor, the fourth transistor, the fifth transistor, the sixth transistor, and the seventh transistor are all used to receive the power supply voltage.

[0016] The gate of the third transistor is connected to the output terminal of the zeroth operational amplifier, and the output terminal of the zeroth operational amplifier is used to output the second bias voltage.

[0017] The positive input terminal of the zeroth operational amplifier is connected to the drain of the third transistor and the first terminal of the first resistor, and the negative input terminal of the zeroth operational amplifier is connected to the drain of the fourth transistor, the negative input terminal of the first operational amplifier, and the emitter of the zeroth transistor.

[0018] The common node of the second end of the first resistor and the first end of the zeroth resistor is connected to the adjustment module as the first adjustment control terminal.

[0019] The gate of the fourth transistor is connected to the gate of the fifth transistor, the output terminal of the first operational amplifier, and one end of the startup circuit.

[0020] The output of the first operational amplifier is used to output the first bias voltage.

[0021] The positive input terminal of the first operational amplifier is connected to the drain of the fifth transistor and the first terminal of the second resistor.

[0022] The second end of the second resistor is connected to the emitter of the first transistor.

[0023] The gate of the sixth transistor is used to receive the second bias voltage, and the gate of the seventh transistor is used to receive the first bias voltage.

[0024] The drain of the sixth transistor is connected to the drain of the seventh transistor and the first terminal of the third resistor.

[0025] The common node of the second end of the third resistor and the first end of the fourth resistor is connected to the adjustment module as the second adjustment control terminal.

[0026] The second terminal of the zeroth resistor, the base and collector of the zeroth transistor, the base and collector of the first transistor, and the second terminal of the fourth resistor are all grounded.

[0027] In one possible implementation, the zeroth resistor, the first resistor, the second resistor, and the third resistor are all unsalicided p-polysilicon (rppolyu) resistors.

[0028] In one possible implementation, the tuning module includes an eighth transistor, a ninth transistor, a tenth transistor, an eleventh transistor, and a fifth resistor, wherein,

[0029] The source of the eighth transistor, the first terminal of the fifth resistor, and the source of the eleventh transistor are used to receive the power supply voltage.

[0030] The gate of the eighth transistor is used to receive a first bias voltage, and the drain of the eighth transistor is connected to the gate of the ninth transistor, the drain of the ninth transistor, and the gate of the tenth transistor.

[0031] The second terminal of the fifth resistor is connected to the gate of the eleventh transistor and the drain of the tenth transistor.

[0032] The drain of the eleventh transistor is connected to the second adjustment control terminal in the bandgap reference voltage source module, and the drain of the eleventh transistor is used to output the bandgap reference voltage.

[0033] The source of the ninth transistor and the source of the tenth transistor are grounded.

[0034] In one possible implementation, the fifth resistor is an adjustable positive temperature coefficient resistor, and the temperature coefficient of the fifth resistor is greater than that of the second resistor in the bandgap reference voltage source module. The adjustment module further includes a zero-mode selection switch and a first-mode selection switch, wherein...

[0035] The first terminal of the zero-mode selection switch is connected to the first adjustment control terminal in the bandgap reference voltage source module, and the second terminal of the zero-mode selection switch is grounded.

[0036] The first terminal of the first mode selection switch is connected to the second adjustment control terminal in the bandgap reference voltage source module, and the second terminal of the first mode selection switch is connected to the drain of the eleventh transistor.

[0037] The control terminal of the zeroth mode selection switch and the control terminal of the first mode selection switch are used to receive switch control signals to achieve mode switching.

[0038] In one possible implementation, the circuit further includes a control module connected to the resistance adjustment terminal of the fifth resistor, the control terminal of the zeroth mode selection switch, and the control terminal of the first mode selection switch, for:

[0039] Output the first set of switch control signals to control the circuit to work in calibration mode. In the calibration mode, both the zero mode selection switch and the first mode selection switch are set to the on state.

[0040] In the calibration mode, the first bandgap reference voltage and the second bandgap reference voltage output from the drain of the eleventh transistor are acquired at a first preset temperature and a second preset temperature, respectively. The resistance of the fifth resistor is adjusted based on the first and second bandgap reference voltages and an output resistance adjustment signal.

[0041] Wherein, the first preset temperature is lower than the second preset temperature.

[0042] Wherein, at the first preset temperature, the compensation current flowing through the drain of the eleventh transistor is less than a preset value.

[0043] In one possible implementation, adjusting the resistance of the fifth resistor based on the output resistance adjustment signals of the first bandgap reference voltage and the second bandgap reference voltage includes:

[0044] At the second preset temperature, the resistance of the fifth resistor is adjusted using the resistance adjustment signal until the voltage value of the second bandgap reference voltage is equal to or approximately equal to the voltage value of the first bandgap reference voltage.

[0045] In one possible implementation, the control module is further configured to:

[0046] A second set of switch control signals is output to control the circuit to operate in normal working mode. In normal working mode, both the zeroth mode selection switch and the first mode selection switch are set to the off state.

[0047] According to one aspect of this disclosure, an electronic device is provided, the electronic device including the bandgap reference circuit described above.

[0048] The bandgap reference circuit of this embodiment provides a startup current through a startup module, causing the bandgap reference voltage source module to leave the zero degeneracy state and enter the normal operating state. The bandgap reference voltage source module receives the startup current and the power supply voltage to generate an intermediate voltage. The temperature coefficient of the bandgap reference voltage source module is compensated by a trimming module, and a bandgap reference voltage is generated based on the intermediate voltage to compensate for the temperature coefficient of the bandgap reference voltage source module, so as to achieve a lower temperature coefficient across the entire temperature range.

[0049] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0050] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the specification, serve to illustrate the technical solutions of this disclosure.

[0051] Figure 1 A block diagram of a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0052] Figure 2 A block diagram of a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0053] Figure 3 A schematic diagram showing the relationship between various voltages and temperature in the bandgap reference circuit is shown.

[0054] Figure 4 A schematic diagram of a first-order bandgap reference voltage source is shown.

[0055] Figure 5 A schematic diagram of the intermediate voltage output by the bandgap reference voltage source module in a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0056] Figure 6 A schematic diagram of the voltage output by a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0057] Figure 7A partial structural schematic diagram of the adjustment module in a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0058] Figure 8 A schematic diagram of voltage curves obtained after resistance calibration of voltage at different temperatures is shown.

[0059] Figure 9 A schematic diagram of the temperature coefficient simulation results after curvature compensation is shown. Detailed Implementation

[0060] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0061] In the description of this disclosure, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0062] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this disclosure, "a plurality of" means two or more, unless otherwise expressly specified.

[0063] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0064] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0065] In this document, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A alone, A and B simultaneously, and B alone. Furthermore, the term "at least one" in this document means any combination of at least two of any one or more elements. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0066] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0067] Please see Figure 1 , Figure 1 A block diagram of a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0068] like Figure 1 As shown, the circuit includes:

[0069] Startup module 10 is used to provide startup current;

[0070] The bandgap reference voltage source module 20 is connected to the startup module 10 and is used to receive the startup current and power supply voltage to generate an intermediate voltage. The startup current is used to make the bandgap reference voltage source module 20 leave the zero degeneracy state and enter the normal operation state.

[0071] The adjustment module 30 is connected to the bandgap reference voltage source module 20 and is used to compensate the temperature coefficient of the bandgap reference voltage source module 20 and generate a bandgap reference voltage based on the intermediate voltage.

[0072] The bandgap reference circuit of this embodiment provides a startup current through the startup module 10, causing the bandgap reference voltage source module 20 to leave the zero degeneracy state and enter the normal operation state. The bandgap reference voltage source module 20 receives the startup current and the power supply voltage VDD to generate an intermediate voltage. The temperature coefficient of the bandgap reference voltage source module 20 is compensated by the adjustment module 30, and a bandgap reference voltage is generated based on the intermediate voltage to compensate for the temperature coefficient of the bandgap reference voltage source module 20, so as to achieve a lower temperature coefficient across the entire temperature range.

[0073] The present disclosure does not limit the specific implementation of the startup module 10, the bandgap reference voltage source module 20, and the adjustment module 30. Those skilled in the art can adopt appropriate technical means to implement them according to actual conditions and needs, as long as each module can achieve the corresponding function.

[0074] The following provides an exemplary description of the preferred implementation methods of the startup module 10, the bandgap reference voltage source module 20, and the adjustment module 30.

[0075] Please see Figure 2 , Figure 2 A block diagram of a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0076] In one possible implementation, such as Figure 2 As shown, the startup module 10 may include a zeroth transistor M0, a first transistor M1, and a second transistor M2, wherein,

[0077] The gate of the zeroth transistor M0 is grounded (GND), the source of the zeroth transistor M0 is used to receive the power supply voltage VDD, and the drain of the zeroth transistor M0 is connected to the drain of the first transistor M1 and the gate of the second transistor M2.

[0078] The gate of the first transistor M1 is used to receive the start control signal VN.

[0079] The drain of the second transistor M2 is used to receive the first bias voltage PBIAS1.

[0080] The source of the first transistor M1 and the source of the second transistor M2 are grounded.

[0081] In this embodiment, the starting module 10 injects a starting current into the VN node to prevent the bandgap reference voltage source module 20 from entering a zero degeneracy point state when powered on. Here, the degeneracy point refers to the DC static operating point at which the circuit can stabilize. When the circuit starts working, there may be several static operating points. For the bandgap reference voltage source module 20, there are often two or more degeneracy points. It is necessary to design a starting circuit to eliminate the degeneracy points that are not needed in the design, so that the circuit can work in the state required by the design.

[0082] In one possible implementation, such as Figure 2As shown, the bandgap reference voltage source module 20 can be a first-order current-type bandgap reference voltage source. The bandgap reference voltage source module 20 may include a zero-th resistance R0, a first resistance R1, a second resistance R2, a third resistance R3, a fourth resistance R4, a third transistor M3, a fourth transistor M4, a fifth transistor M5, a sixth transistor M6, a seventh transistor M7, a zero-th transistor Q0, a first transistor Q1, a zero-th operational amplifier OPA0, and a first operational amplifier OPA1.

[0083] The sources of the third transistor M3, the fourth transistor M4, the fifth transistor M5, the sixth transistor M6, and the seventh transistor M7 are all used to receive the power supply voltage VDD.

[0084] The gate of the third transistor M3 is connected to the output terminal of the zeroth operational amplifier OPA0, and the output terminal of the zeroth operational amplifier OPA0 is used to output the second bias voltage PBIAS2.

[0085] The positive input terminal of the zeroth operational amplifier OPA0 is connected to the drain of the third transistor M3 and the first terminal of the first resistor R1. The negative input terminal of the zeroth operational amplifier OPA0 is connected to the drain of the fourth transistor M4, the negative input terminal of the first operational amplifier OPA1, and the emitter of the zeroth transistor Q0.

[0086] The common node of the second end of the first resistor R1 and the first end of the zeroth resistor R0 is connected to the adjustment module 30 as the first adjustment control terminal.

[0087] The gate of the fourth transistor M4 is connected to the gate of the fifth transistor M5, the output terminal of the first operational amplifier OPA1, and one end of the startup circuit.

[0088] The output of the first operational amplifier OPA1 is used to output the first bias voltage PBIAS1.

[0089] The positive input terminal of the first operational amplifier OPA1 is connected to the drain of the fifth transistor M5 and the first terminal of the second resistor R2.

[0090] The second end of the second resistor R2 is connected to the emitter of the first transistor Q1.

[0091] The gate of the sixth transistor M6 is used to receive the second bias voltage PBIAS2, and the gate of the seventh transistor M7 is used to receive the first bias voltage PBIAS1.

[0092] The drain of the sixth transistor M6 is connected to the drain of the seventh transistor M7 and the first terminal of the third resistor R3.

[0093] The common node of the second end of the third resistor R3 and the first end of the fourth resistor R4 is connected to the adjustment module 30 as the second adjustment control terminal.

[0094] The second terminal of the zeroth resistor R0, the base and collector of the zeroth transistor Q0, the base and collector of the first transistor Q1, and the second terminal of the fourth resistor R4 are all grounded.

[0095] This disclosure does not limit the specific resistance types of the zero-th resistor R0, the first resistor R1, the second resistor R2, and the third resistor R3. Those skilled in the art can set them according to actual conditions and needs. For example, in one possible implementation, the zero-th resistor R0, the first resistor R1, the second resistor R2, and the third resistor R3 can all be unsalicided p-polysilicon resistors (rppolyu) resistors.

[0096] Please see Figure 3 , Figure 3 A schematic diagram showing the relationship between various voltages and temperature in the bandgap reference circuit is shown.

[0097] Positive temperature coefficient voltage ( ) and negative temperature coefficient voltage ( The slopes of voltages with smaller slopes (such as the PTAT voltage) are typically different. In embodiments of this disclosure, a temperature-independent coefficient can be multiplied by the voltage with the smaller slope (here, the PTAT voltage). If the absolute values ​​of the slopes of these two voltages are equal, then adding these two curves together will yield a bandgap voltage curve that is independent of (or almost independent of) temperature.

[0098] If only the first-order temperature coefficient is considered, the base-emitter voltage of the transistor... (like Figure 3 of (As shown by the dashed line). This can be achieved by selecting an appropriate scaling factor. To compensate for the positive and negative temperature coefficients in order to realize a first-order bandgap reference voltage source.

[0099] The coefficients are as follows The determination method is described by way of example.

[0100] Please see Figure 4 , Figure 4 A schematic diagram of a first-order bandgap reference voltage source is shown.

[0101] Assume that the output reference voltage of the first-order bandgap voltage source is:

[0102]

[0103] in This is a coefficient that is independent of temperature.

[0104] The negative temperature coefficient voltage is:

[0105]

[0106] in, For the transistor in the bandgap reference voltage source (such as Figure 2 The voltage between the base and emitter of the zeroth transistor Q0 or the first transistor Q1 in the transistor is a negative temperature coefficient voltage. This is the bandgap voltage of silicon at 27°C (e.g., 1.205V). Where is Boltzmann's constant, and T is the relative voltage. For absolute reference voltage, for The voltage between the base and emitter of the transistor is given by q, where q is the number of electrons. A coefficient related to temperature. The diode's current density, for The current density of the diode.

[0107] like Figure 4 As shown, when two current sources flow into two diodes, which can also be transistors with their collectors connected to their bases, the voltage difference across them... It is a positive temperature coefficient voltage, which can be expressed as:

[0108]

[0109] if The above formula shows It is a positive temperature coefficient voltage.

[0110] Perform the following calculations:

[0111] ;

[0112] ;

[0113] ;

[0114] A coefficient independent of temperature can be obtained. for:

[0115]

[0116] The output reference voltage of the first-order bandgap reference voltage source can be obtained as follows:

[0117]

[0118] This disclosure embodiment can utilize coefficients. A first-order bandgap reference voltage source is achieved by compensating for voltages with a small slope, such as PTAT voltage. However, due to the influence of higher-order terms, even with positive temperature coefficient compensation by setting a reasonable coefficient m, the temperature coefficient of the first-order bandgap reference voltage source is still as high as 20ppm / ℃. Therefore, this embodiment proposes to use a trimming module 30 to compensate for the temperature coefficient of the bandgap reference voltage source module 20 and generate a bandgap reference voltage based on the intermediate voltage to achieve a lower temperature coefficient.

[0119] For example, such as Figure 2 As shown, based on the principle of virtual shorting between the positive and negative terminals of operational amplifier negative feedback, the positive input voltage of the zeroth operational amplifier OPA0 is equal to the negative input voltage, which is also equal to the base-emitter voltage of the zeroth transistor Q0. Therefore, a negative temperature coefficient current can be obtained ( ):

[0120] ;

[0121] in, This represents the resistance value of the zeroth resistor, R0. This indicates the resistance value of the first resistor, R1.

[0122] Similarly, the positive input voltage of the first operational amplifier OPA1 is equal to the negative input voltage, which is also equal to the base-emitter voltage of the first transistor Q1. Therefore, a positive temperature coefficient current can be obtained ( ):

[0123] ;

[0124] in, This indicates the resistance value of the second resistor, R2.

[0125] The positive temperature coefficient current is mirrored through a current mirror (including the sixth transistor M6 and the seventh transistor M7). and negative temperature coefficient current And by allowing these resistors to flow through the third resistor R3 and the fourth resistor R4, by selecting appropriate zero-th resistor R0, first resistor R1, second resistor R2, third resistor R3, and fourth resistor R4, an intermediate voltage independent of the first-order temperature coefficient can be obtained. :

[0126] ;

[0127] in, This indicates the resistance value of the third resistor, R3. This indicates the resistance value of the fourth resistor, R4.

[0128] Please see Figure 5 , Figure 5 A schematic diagram of the intermediate voltage output by the bandgap reference voltage source module 20 in a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0129] because Figure 2 The base-emitter voltage of the transistor in the bandgap reference voltage source module 20 also contains higher-order terms, therefore, as Figure 5 As shown, the resulting temperature curve is a parabola that is low at both ends and high in the middle, and the temperature coefficient can be as low as... about.

[0130] Therefore, in this embodiment of the present disclosure, the temperature coefficient of the bandgap reference voltage source module 20 is compensated by the adjustment module 30 to achieve a lower temperature coefficient over the entire temperature range.

[0131] In one possible implementation, such as Figure 2 As shown, the adjustment module 30 may include an eighth transistor M8, a ninth transistor M9, a tenth transistor M10, an eleventh transistor M11, and a fifth resistor R5, wherein...

[0132] The source of the eighth transistor M8, the first terminal of the fifth resistor R5, and the source of the eleventh transistor M11 are used to receive the power supply voltage VDD.

[0133] The gate of the eighth transistor M8 is used to receive the first bias voltage PBIAS1, and the drain of the eighth transistor M8 is connected to the gate of the ninth transistor M9, the drain of the ninth transistor M9, and the gate of the tenth transistor M10.

[0134] The second terminal of the fifth resistor R5 is connected to the gate of the eleventh transistor M11 and the drain of the tenth transistor M10.

[0135] The drain of the eleventh transistor M11 is connected to the second adjustment control terminal in the bandgap reference voltage source module 20, and the drain of the eleventh transistor M11 is used to output the bandgap reference voltage.

[0136] The source of the ninth transistor M9 and the source of the tenth transistor M10 are grounded.

[0137] By appropriately setting the value of the fifth resistor R5, the embodiments of this disclosure can enable the bandgap reference circuit to achieve a low temperature coefficient within the operating temperature range and output an accurate and stable bandgap voltage.

[0138] Of course, the specific setting and calibration method of the fifth resistor R5 are not limited in this embodiment. Those skilled in the art can use relevant technologies to implement it according to actual conditions and needs. The preferred implementation methods are described below by way of example.

[0139] In one possible implementation, the fifth resistor R5 can be a positive temperature coefficient resistor with an adjustable resistance value. The temperature coefficient of the fifth resistor R5 is greater than the temperature coefficient of the second resistor R2 in the bandgap reference voltage source module 20, such as... Figure 2 As shown, the adjustment module 30 may further include a zero mode selection switch SW0 and a first mode selection switch SW1, wherein,

[0140] The first terminal of the zero-mode selection switch SW0 is connected to the first adjustment control terminal (the common node of the second terminal of the first resistor R1 and the first terminal of the zero-mode resistor R0) in the bandgap reference voltage source module 20, and the second terminal of the zero-mode selection switch SW0 is grounded.

[0141] The first terminal of the first mode selection switch SW1 is connected to the second adjustment control terminal in the bandgap reference voltage source module 20 (the common node of the second terminal of the third resistor R3 and the first terminal of the fourth resistor R4), and the second terminal of the first mode selection switch SW1 is connected to the drain of the eleventh transistor M11.

[0142] The control terminal of the zero mode selection switch SW0 and the control terminal of the first mode selection switch SW1 are used to receive switch control signals to achieve mode switching.

[0143] In one example, in the calibration mode, both the zero-mode selection switch SW0 and the first-mode selection switch SW1 are set to the on state, so that the resistance of the fifth resistor R5 can be adjusted according to the output bandgap reference voltage at different temperatures to achieve calibration; in the normal operation mode, both the zero-mode selection switch SW0 and the first-mode selection switch SW1 are set to the off state, so that the bandgap reference circuit can work normally.

[0144] Please see Figure 6 , Figure 6 A schematic diagram of the voltage output by a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0145] For example, such as Figure 6As shown, after temperature coefficient compensation is performed using the adjustment module 30 with adjustment voltage, the temperature coefficient of the bandgap voltage output by the bandgap reference circuit decreases as the temperature rises, exhibiting higher stability compared to a typical BGR.

[0146] The present disclosure does not limit the specific implementation method of adjusting the resistance of the fifth resistor R5 according to the output bandgap reference voltage at different temperatures to achieve calibration. Those skilled in the art can use relevant technologies to implement it according to actual conditions and needs.

[0147] In one possible implementation, the circuit may further include a control module (not shown), which is connected to the resistance adjustment terminal of the fifth resistor R5, the control terminal of the zeroth mode selection switch SW0, and the control terminal of the first mode selection switch SW1, and is used for:

[0148] Output the first set of switch control signals to control the circuit to work in calibration mode. In the calibration mode, both the zero mode selection switch SW0 and the first mode selection switch SW1 are set to the on state.

[0149] In the calibration mode, the first bandgap reference voltage and the second bandgap reference voltage output from the drain of the eleventh transistor M11 are acquired at a first preset temperature and a second preset temperature, respectively. The resistance of the fifth resistor R5 is adjusted according to the resistor adjustment signal output based on the first and second bandgap reference voltages.

[0150] Wherein, the first preset temperature is lower than the second preset temperature.

[0151] Wherein, at the first preset temperature, the compensation current flowing through the drain of the eleventh transistor M11 is less than a preset value.

[0152] In one possible implementation, adjusting the resistance of the fifth resistor R5 according to the output resistance adjustment signals of the first bandgap reference voltage and the second bandgap reference voltage may include:

[0153] At the second preset temperature, the resistance of the fifth resistor R5 is adjusted using the resistance adjustment signal until the voltage value of the second bandgap reference voltage is equal to or approximately equal to the voltage value of the first bandgap reference voltage.

[0154] In one possible implementation, the control module can also be used for:

[0155] A second set of switch control signals is output to control the circuit to operate in normal working mode. In normal working mode, both the zero mode selection switch SW0 and the first mode selection switch SW1 are set to the off state.

[0156] The working principle and operation mode of the adjustment module 30 are described below by way of example.

[0157] Please see Figure 7 , Figure 7 A partial structural schematic diagram of the trimming module 30 in a bandgap reference circuit according to an embodiment of the present disclosure is shown.

[0158] For example, such as Figure 2 As shown, in this embodiment of the present disclosure, a current mirror formed by the eighth transistor M8, the ninth transistor M9, and the tenth transistor M10 is used to mirror the positive temperature coefficient current and allow it to flow through the fifth resistor R5 (e.g., Figure 7 shown ), resulting in a voltage that is proportional to the square of the temperature ( ).

[0159] For example, such as Figure 2 As shown, the output reference voltage after adding the trimming module 30 for:

[0160] ;

[0161] Differentiating the above equation yields:

[0162] ;

[0163] Source-gate voltage of the eleventh transistor M11 for:

[0164] ;

[0165] Among them, when No current will flow through M11; when near When M11 operates in the weak inversion region, the drain current of the eleventh transistor M11 can be obtained. :

[0166] ;

[0167] when , It is approximately equal to zero. And because Therefore, we get That is, the drain current of the eleventh transistor M11 It is related to the temperature index T.

[0168] when Greater than When M11 operates in the strong inversion region, the drain current of the eleventh transistor M11 can be obtained. :

[0169] ;

[0170] Because of migration rate Therefore, we obtain That is, the drain current of the eleventh transistor M11 It is related to the square of temperature T.

[0171] For example, the drain current of the eleventh transistor M11 The relationship with temperature T can be expressed as:

[0172] ;

[0173] According to the above formula, when the temperature is less than The compensation current is zero; when the temperature The compensation current increases exponentially with increasing temperature; when the temperature is greater than... The compensation current increases with temperature and is proportional to the square of the temperature.

[0174] By way of example, embodiments of this disclosure can be achieved through reasonable design. The value of the fifth resistor R5 and the aspect ratio of the eleventh transistor M11 can be designed to achieve the desired temperature when the temperature is below a certain level. (e.g., at 25℃), the nonlinear calibration current is zero, corresponding to the above formula. The situation is when the temperature is less than The compensation current is zero;

[0175] When the temperature belongs to In cases such as temperatures above 25°C and below 70°C, the nonlinear compensation current increases exponentially with increasing temperature.

[0176] When the temperature is greater than For example, at 70℃, the compensation current increases with the square of the temperature.

[0177] Therefore, since the slope of the temperature coefficient of the nonlinear compensation current is only at temperatures greater than 25℃ and less than 70℃... The slope is greater than the slope of the temperature coefficient of the negative temperature coefficient term at this time. Therefore, it is reflected in The output gradually increases from decreasing.

[0178] When the temperature is above 70℃, the slope of the temperature coefficient of the compensation current The slope of this temperature coefficient is less than the slope of the negative temperature coefficient term at this time, and therefore it is reflected in the reference voltage. The output gradually decreases from increasing to decreasing, therefore, the reference voltage at 70℃ can be adjusted. This value can provide a reference voltage source with a small deviation across the entire temperature range.

[0179] For example, due to the relationship between curvature compensation, the resistance value of the fifth resistor R5, and the threshold voltage of the eleventh transistor M11, it is difficult for the factory to guarantee absolute precision during manufacturing. Therefore, for a high-precision reference voltage source, each chip needs to be factory-calibrated. Changing the value of the fifth resistor R5 can adjust... The larger the temperature, the larger the fifth resistor R5. The smaller the value, the larger it is;

[0180] For example, a value can be measured at room temperature of 25°C. Output voltage At this time, the corresponding temperature is less than In this case, the gate-source voltage of the eleventh transistor M11 Then, the output voltage of another Vref was measured at 75°C. The corresponding temperature at this time is The surrounding environment, the gate-source voltage of the eleventh transistor M11 By adjusting the calibration value of the fifth resistor R5, the gate-source voltage of the eleventh transistor M11 can be increased or decreased. Increasing the value of the fifth resistor R5 can increase the gate-source voltage of the eleventh transistor M11. This increases the compensation current flowing out of the eleventh transistor M11. This increases the influence of the positive temperature coefficient term of the compensation current in the reference voltage source, and vice versa. The resistance value can be reduced This reduces the compensation current flowing out of the eleventh transistor M11. This reduces the influence of the positive temperature coefficient term of the compensation current. The resistance value of the fifth resistor, R5, is adjusted to achieve this. This indicates that the positive and negative temperature coefficient terms of the reference voltage source cancel each other out, thus achieving the purpose of curvature calibration.

[0181] Please see Figure 8 , Figure 9 , Figure 8 A schematic diagram of voltage curves obtained after resistance calibration at different temperatures is shown. Figure 9 A schematic diagram of the temperature coefficient simulation results after curvature compensation is shown.

[0182] For example, such as Figure 8 As shown, for voltage values ​​obtained at different temperatures, such as V2 being greater than V1 or V2 being less than V1, the output temperature can be made equal (V2 = V1) after calibration and adjustment by the adjustment module 30.

[0183] This embodiment of the invention can eliminate the effects of process deviations by adjusting the value of the fifth resistor R5, and the output reference voltage after curvature compensation can achieve a lower temperature coefficient. Figure 9 As shown, its temperature coefficient decreases to 1.4 ppm / ℃.

[0184] In this embodiment, the starting module 10 outputs a starting current to enable the circuit to leave the zero degenerate state and enter the normal operating state. A bandgap reference voltage source module 20 (such as a first-order current-type bandgap reference voltage source) is used to provide an intermediate voltage with a low temperature coefficient. The adjustment module 30 is used to perform segmented compensation on the temperature coefficient of the bandgap reference voltage source module 20 to achieve an even lower temperature coefficient. The adjusted circuit can achieve a lower temperature coefficient over the entire temperature range, and its simple structure helps to reduce costs.

[0185] According to one aspect of this disclosure, an electronic device is provided, the electronic device including the bandgap reference circuit described above.

[0186] The embodiments disclosed herein do not limit the specific type of electronic device. Those skilled in the art can set it according to actual conditions and needs. The electronic device may include devices such as voltage regulators, analog-to-digital converters (ADCs) and digital-to-analog converters (DACs) with bandgap reference circuits. For example, the electronic device may include terminal equipment. In one example, a terminal is also called user equipment (UE), mobile station (MS), mobile terminal (MT), etc., and is a device that provides voice and / or data connectivity to users. For example, handheld devices with wireless connection functions, vehicle-mounted devices, etc. Currently, some examples of terminals include: mobile phones, tablets, laptops, PDAs, mobile internet devices (MIDs), wearable devices, virtual reality (VR) devices, augmented reality (AR) devices, wireless terminals in industrial control, wireless terminals in self-driving, wireless terminals in remote medical surgery, wireless terminals in smart grids, wireless terminals in transportation safety, wireless terminals in smart cities, wireless terminals in smart homes, and wireless terminals in vehicle-to-everything (V2X) networks.

[0187] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A bandgap reference circuit, characterized in that, The circuit includes: The startup module is used to provide the startup current; A bandgap reference voltage source module is connected to the startup module and is used to receive the startup current and power supply voltage to generate an intermediate voltage. The startup current is used to enable the bandgap reference voltage source module to leave the zero degeneracy state and enter the normal operation state. The adjustment module, connected to the bandgap reference voltage source module, is used to compensate for the temperature coefficient of the bandgap reference voltage source module and generate a bandgap reference voltage based on the intermediate voltage. The bandgap reference voltage source module includes a zero-th resistor, a first resistor, a second resistor, a third resistor, a fourth resistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a seventh transistor, a zero-th transistor, a first transistor, a zero-th operational amplifier, and a first operational amplifier. The sources of the third transistor, the fourth transistor, the fifth transistor, the sixth transistor, and the seventh transistor are all used to receive the power supply voltage. The gate of the third transistor is connected to the output terminal of the zero-th operational amplifier. The output terminal of the zero-th operational amplifier is used to output a second bias voltage. The positive input terminal of the zero-th operational amplifier is connected to the drain of the third transistor and the first end of the first resistor. The negative input terminal of the zero-th operational amplifier is connected to the drain of the fourth transistor, the negative input terminal of the first operational amplifier, and the emitter of the zero-th transistor. The common node of the second end of the first resistor and the first end of the zero-th resistor is... The fourth transistor is connected to the tuning module as the first tuning control terminal. The gate of the fourth transistor is connected to the gate of the fifth transistor, the output of the first operational amplifier, and one end of the startup module. The output of the first operational amplifier is used to output a first bias voltage. The positive input of the first operational amplifier is connected to the drain of the fifth transistor and the first end of the second resistor. The second end of the second resistor is connected to the emitter of the first transistor. The gate of the sixth transistor is used to receive the second bias voltage. The gate of the seventh transistor is used to receive the first bias voltage. The drain of the sixth transistor is connected to the drain of the seventh transistor and the first end of the third resistor. The common node of the second end of the third resistor and the first end of the fourth resistor serves as the second tuning control terminal connected to the tuning module. The second end of the zeroth resistor, the base and collector of the zeroth transistor, the base and collector of the first transistor, and the second end of the fourth resistor are all grounded. The adjustment module includes an eighth transistor, a ninth transistor, a tenth transistor, an eleventh transistor, and a fifth resistor. The source of the eighth transistor, the first terminal of the fifth resistor, and the source of the eleventh transistor are used to receive the power supply voltage. The gate of the eighth transistor is used to receive a first bias voltage. The drain of the eighth transistor is connected to the gate, drain, and gate of the ninth transistor. The second terminal of the fifth resistor is connected to the gate and drain of the eleventh transistor. The drain of the eleventh transistor is connected to the second adjustment control terminal in the bandgap reference voltage source module. The drain of the eleventh transistor is used to output the bandgap reference voltage. The sources of the ninth and tenth transistors are grounded. The fifth resistor is an adjustable positive temperature coefficient resistor, and its temperature coefficient is greater than that of the second resistor in the bandgap reference voltage source module. The adjustment module also includes a zero-mode selection switch and a first-mode selection switch. The first terminal of the zero-mode selection switch is connected to the first adjustment control terminal in the bandgap reference voltage source module, and the second terminal of the zero-mode selection switch is grounded. The first terminal of the first-mode selection switch is connected to the second adjustment control terminal in the bandgap reference voltage source module, and the second terminal of the first-mode selection switch is connected to the drain of the eleventh transistor. The control terminals of the zero-mode selection switch and the first-mode selection switch are used to receive switch control signals to achieve mode switching.

2. The circuit according to claim 1, characterized in that, The startup module includes a zeroth transistor, a first transistor, and a second transistor, wherein, The gate of the zeroth transistor is grounded, the source of the zeroth transistor is used to receive the power supply voltage, and the drain of the zeroth transistor is connected to the drain of the first transistor and the gate of the second transistor. The gate of the first transistor is used to receive a start control signal. The drain of the second transistor is used to receive the first bias voltage. The source of the first transistor and the source of the second transistor are grounded.

3. The circuit according to claim 1, characterized in that, The zeroth resistor, the first resistor, the second resistor, and the third resistor are all unsalicided p-polysilicon resistors (rppolyu) without metal silicide.

4. The circuit according to claim 1, characterized in that, The circuit further includes a control module, which is connected to the resistance adjustment terminal of the fifth resistor, the control terminal of the zeroth mode selection switch, and the control terminal of the first mode selection switch, and is used for: Output the first set of switch control signals to control the circuit to work in calibration mode. In the calibration mode, both the zero mode selection switch and the first mode selection switch are set to the on state. In the calibration mode, the first bandgap reference voltage and the second bandgap reference voltage output from the drain of the eleventh transistor are acquired at a first preset temperature and a second preset temperature, respectively. The resistance of the fifth resistor is adjusted based on the first and second bandgap reference voltages and an output resistance adjustment signal. Wherein, the first preset temperature is lower than the second preset temperature. Wherein, at the first preset temperature, the compensation current flowing through the drain of the eleventh transistor is less than a preset value.

5. The circuit according to claim 4, characterized in that, The resistance of the fifth resistor is adjusted according to the output resistance adjustment signals of the first bandgap reference voltage and the second bandgap reference voltage, including: At the second preset temperature, the resistance of the fifth resistor is adjusted using the resistance adjustment signal until the voltage value of the second bandgap reference voltage is equal to or approximately equal to the voltage value of the first bandgap reference voltage.

6. The circuit according to claim 4, characterized in that, The control module is also used for: A second set of switch control signals is output to control the circuit to operate in normal working mode. In normal working mode, both the zeroth mode selection switch and the first mode selection switch are set to the off state.

7. An electronic device, characterized in that, The electronic device includes a bandgap reference circuit as described in any one of claims 1-6.

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