Electronic product, bandgap reference circuit and trimming method thereof

Abstract

This invention provides an electronic product, a bandgap reference circuit, and a method for adjusting the same. The circuit includes a bandgap reference voltage generation module and a temperature compensation module. The temperature compensation module provides temperature compensation to the bandgap reference voltage generation module to reduce the temperature drift coefficient. The bandgap reference voltage generation module is a current-mode structure, including first, second, third, and fourth resistors, first and second transistors, first, second, and third amplifying transistors, and an operational amplifier. The first and second resistors are of the same type and both exhibit a first temperature drift characteristic. The third and fourth resistors are of the same type and both exhibit a second temperature drift characteristic. The combined temperature drift characteristic of the resistors is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor. This invention achieves ultra-low temperature drift characteristics through a complementary approach of temperature compensation module and resistors, with low power consumption. Furthermore, because this invention uses resistor-based temperature drift compensation, the adjustment method is greatly simplified, making it suitable for mass-produced chips.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit design, and in particular to an electronic product, a bandgap reference circuit, and a method for adjusting the bandgap. Background Technology

[0002] The bandgap reference is the core of a chip, and a bandgap reference with a low temperature drift coefficient is particularly important for the stable operation of the chip, especially for high-precision measurement chips. For many processes, especially CMOS processes, the lack of high-amplification BJTs (Bipolar Junction Transistors) makes it difficult to obtain a bandgap reference voltage with low temperature drift. To obtain a reference voltage with a temperature drift of less than 5ppm, a secondary temperature compensation strategy is usually required. Secondary temperature compensation strategies often bring the following problems: significantly increased power consumption; typically excellent compensation effect, but under other process characteristics and deviations, the temperature drift will change drastically, and the adjustment process is too complex and impractical, making it extremely difficult to apply to mass-produced chips.

[0003] Therefore, how to provide a bandgap reference circuit with extremely low temperature drift (less than or equal to 5ppm), low power consumption, easy adjustment, and suitable for application in mass-produced chips has become one of the problems that urgently need to be solved by those skilled in the art.

[0004] It should be noted that the above description of the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of this invention. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an electronic product, a bandgap reference circuit and its adjustment method, to solve the problems of large temperature drift, high power consumption, difficulty in adjustment and difficulty in application to mass-produced chips in the prior art.

[0006] To achieve the above and other related objectives, the present invention provides a bandgap reference circuit, the bandgap reference circuit comprising at least:

[0007] A bandgap reference voltage generation module and a temperature compensation module, wherein the temperature compensation module provides temperature compensation for the bandgap reference voltage generation module, thereby reducing the temperature drift coefficient of the bandgap reference voltage generation module;

[0008] The bandgap reference voltage generation module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first transistor, a second transistor, a first amplifying tube, a second amplifying tube, a third amplifying tube, and an operational amplifier. The first amplifying tube, the second amplifying tube, and the third amplifying tube constitute a current mirror structure.

[0009] The first, second, and third amplifying transistors are connected to a power supply voltage at their first ends. The second end of the first amplifying transistor is grounded via a first resistor, the second end of the second amplifying transistor is grounded via a second resistor, and the second end of the third amplifying transistor outputs a bandgap reference voltage and is grounded via a third resistor. The control terminal of each amplifying transistor is connected to the output terminal of the operational amplifier. The second end of the first amplifying transistor is connected to the first input terminal of the operational amplifier, and the second end of the second amplifying transistor is connected to the second input terminal of the operational amplifier. The first transistor is connected as a diode, with its first end connected to the first input terminal of the operational amplifier and its second end grounded. The second transistor is connected as a diode, with its first end connected to the second input terminal of the operational amplifier via a fourth resistor and its second end grounded.

[0010] The first resistor and the second resistor are of the same type and both have a first temperature drift characteristic; the third resistor and the fourth resistor are of the same type and both have a second temperature drift characteristic; the temperature drift characteristic of the combination of the first resistor, the second resistor, the third resistor and the fourth resistor is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor.

[0011] Optionally, the first amplifying transistor, the second amplifying transistor, and the third amplifying transistor are PMOS transistors.

[0012] To achieve the above and other related objectives, the present invention also provides a bandgap reference circuit, the bandgap reference circuit comprising at least:

[0013] A bandgap reference voltage generation module and a temperature compensation module, wherein the temperature compensation module provides temperature compensation for the bandgap reference voltage generation module, thereby reducing the temperature drift coefficient of the bandgap reference voltage generation module;

[0014] The bandgap reference voltage generation module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first transistor, a second transistor, a first amplifying tube, a second amplifying tube, a third amplifying tube, and an operational amplifier. The first amplifying tube, the second amplifying tube, and the third amplifying tube constitute a current mirror structure.

[0015] The first, second, and third amplifying transistors have their first terminals grounded. The second terminal of the first amplifying transistor is connected to the power supply voltage via the first resistor. The second terminal of the second amplifying transistor is connected to the power supply voltage via the second resistor. The second terminal of the third amplifying transistor outputs a bandgap reference voltage and is connected to the power supply voltage via the third resistor. The control terminal of each amplifying transistor is connected to the output terminal of the operational amplifier. The second terminal of the first amplifying transistor is connected to the first input terminal of the operational amplifier. The second terminal of the second amplifying transistor is connected to the second input terminal of the operational amplifier. The first transistor is connected as a diode, with its first terminal connected to the first input terminal of the operational amplifier and its second terminal connected to the power supply voltage. The second transistor is connected as a diode, with its first terminal connected to the second input terminal of the operational amplifier via the fourth resistor and its second terminal connected to the power supply voltage.

[0016] The first resistor and the second resistor are of the same type and both have a first temperature drift characteristic; the third resistor and the fourth resistor are of the same type and both have a second temperature drift characteristic; the temperature drift characteristic of the combination of the first resistor, the second resistor, the third resistor and the fourth resistor is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor.

[0017] Optionally, the first amplifying transistor, the second amplifying transistor, and the third amplifying transistor are NMOS transistors.

[0018] Alternatively, the first transistor, the second transistor, and the third transistor may be an NPN transistor, a PNP transistor, an NMOS transistor, or a PMOS transistor.

[0019] Alternatively, the first temperature drift characteristic is a negative temperature drift characteristic, and the second temperature drift characteristic is a positive temperature drift characteristic; or, the first temperature drift characteristic is a positive temperature drift characteristic, and the second temperature drift characteristic is a negative temperature drift characteristic.

[0020] Alternatively, the temperature compensation module includes a fourth amplifying tube, a third transistor, a fifth resistor, and a sixth resistor;

[0021] The first end of the fourth amplifying transistor is connected to the first amplifying transistor, the second amplifying transistor and the first end of the third amplifying transistor, and the second end is connected to the second end of the first transistor and the second transistor via the third transistor.

[0022] One end of the fifth resistor is connected to the second end of the fourth amplifier tube, one end of the sixth resistor is connected to the second end of the fourth amplifier tube, and the other ends of the fifth resistor and the sixth resistor are respectively connected to the input terminals of the operational amplifier.

[0023] The third transistor is the same as the first transistor; the fifth resistor and the sixth resistor have the same resistance value, are of the same type as the first resistor and the second resistor, and all have the first temperature drift characteristic. The temperature drift characteristic of the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor and the sixth resistor combined is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor.

[0024] Alternatively, the resistance value of the fifth resistor is set to 1 / 6 to 1 / 8 of the resistance value of the first resistor.

[0025] Alternatively, the bandgap reference circuit is fabricated using a 40nm or 50nm eflash process.

[0026] Alternatively, the temperature drift coefficient of the bandgap reference circuit is less than or equal to 5 ppm.

[0027] To achieve the above and other related objectives, the present invention also provides a method for adjusting a bandgap reference circuit, the method comprising at least:

[0028] The above-described bandgap reference circuit is provided, wherein the preset bandgap reference voltage of the bandgap reference circuit is a first value; an actual bandgap reference voltage is generated based on the bandgap reference circuit, wherein the actual bandgap reference voltage is a second value; and a trimming ratio is obtained based on the first value and the second value, wherein the trimming ratio satisfies:

[0029]

[0030] Adjust the third resistor and / or the fourth resistor so that their resistance values ​​satisfy:

[0031] R3a=R3b·TR; R4a=R4b·TR;

[0032] Wherein, TR is the adjustment ratio, Vref1 is the first value, Vref2 is the second value, R3a is the adjusted resistance of the third resistor, R3b is the unadjusted resistance of the third resistor, R4a is the adjusted resistance of the fourth resistor, and R4b is the unadjusted resistance of the fourth resistor.

[0033] To achieve the above and other related objectives, the present invention also provides an electronic product, which includes at least the above-described bandgap reference circuit.

[0034] As described above, the electronic product, bandgap reference circuit, and adjustment method of the present invention have the following beneficial effects:

[0035] The electronic product and bandgap reference circuit of this invention achieve ultra-low temperature drift characteristics through temperature compensation module and resistor complementarity, and have low power consumption. In addition, since this invention adopts resistor temperature drift compensation, the adjustment method can be greatly simplified, making it suitable for mass production chips. Attached Figure Description

[0036] Figure 1 The diagram shown is a schematic representation of a bandgap reference circuit according to the present invention.

[0037] Figure 2 The diagram shown is another structural schematic of the bandgap reference circuit of the present invention.

[0038] Component designation explanation

[0039] 1. Bandgap reference circuit

[0040] 11 Bandgap reference voltage generation module

[0041] 111 operational amplifier

[0042] 12 Temperature Compensation Modules Detailed Implementation

[0043] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0044] Please see Figures 1-2 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0045] Example 1

[0046] like Figure 1 As shown, this embodiment provides a bandgap reference circuit 1, which includes:

[0047] Bandgap reference voltage generation module 11 and temperature compensation module 12.

[0048] like Figure 1As shown, the bandgap reference voltage generation module 11 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first transistor Q1, a second transistor Q2, a first amplifier M1, a second amplifier M2, a third amplifier M3, and an operational amplifier 111, wherein the first amplifier M1, the second amplifier M2, and the third amplifier M3 constitute a current mirror structure.

[0049] Specifically, the bandgap reference voltage generation module 11 adopts a current-mode architecture. The first terminals of the first amplifier transistor M1, the second amplifier transistor M2, and the third amplifier transistor M3 are connected to the power supply voltage VDD. The second terminal of the first amplifier transistor M1 is grounded to GND via the first resistor R1. The second terminal of the second amplifier transistor M2 is grounded to GND via the second resistor R2. The second terminal of the third amplifier transistor M3 outputs a bandgap reference voltage Vref and is grounded to GND via the third resistor R3. The control terminal of each amplifier transistor is connected to the output terminal of the operational amplifier 111. The second terminal of the first amplifier transistor M1 is connected to the first input terminal of the operational amplifier 111, and the second terminal of the second amplifier transistor M2 is connected to the second input terminal of the operational amplifier 111. The first transistor Q1 is connected as a diode, with its first terminal connected to the first input terminal of the operational amplifier 111 and its second terminal grounded to GDD. The second transistor Q2 is connected as a diode, with its first terminal connected to the second input terminal of the operational amplifier 111 via the fourth resistor R4 and its second terminal grounded to GND. In this embodiment, the first resistor R1 and the second resistor R2 have the same resistance value, and the emitter area ratio of the first transistor Q1 to the second transistor Q2 is 1:N; as an example, N is set to 8.

[0050] More specifically, in this embodiment, the first amplifier M1, the second amplifier M2, and the third amplifier M3 are PMOS transistors. Correspondingly, the first terminal of each transistor is the source, the second terminal is the drain, and the control terminal is the gate. In practical applications, the device types of the first amplifier M1, the second amplifier M2, and the third amplifier M3 can be configured as needed. Any device capable of current mirroring, such that the current I1 flowing through the first amplifier M1 is equal to the current I2 flowing through the second amplifier M2, is applicable to this invention and is not limited to this embodiment.

[0051] More specifically, in this embodiment, the non-inverting input terminal of the operational amplifier 111 is used as the first input terminal, and the inverting input terminal is used as the second input terminal. In actual use, the correspondence between the input polarity and the input signal can be set as needed, so that the voltages of the two input terminals of the operational amplifier 111 are equal based on the "virtual short" principle of the operational amplifier, and it is not limited to this embodiment.

[0052] More specifically, in this embodiment, the first transistor Q1 and the second transistor Q2 are implemented using PNP transistors. Accordingly, the first terminal of the first transistor Q1 and the second transistor Q2 is the emitter, and the base and collector are connected together as the second terminal grounded GND. In practical applications, any device and structure that can achieve temperature sensing based on a PN junction is applicable to this invention, including but not limited to NPN transistors, PNP transistors (bipolar junction transistors), NMOS transistors, or PMOS transistors (metal-oxide-semiconductor field-effect transistors), which will not be elaborated here.

[0053] like Figure 1 As shown, the temperature compensation module 12 provides temperature compensation for the bandgap reference voltage generation module 11, thereby reducing the temperature drift coefficient of the bandgap reference voltage generation module 11.

[0054] Specifically, the temperature compensation module 12 generates a compensation signal based on the output signal of the operational amplifier 111. The compensation signal acts on the non-inverting input terminal and the inverting input terminal of the operational amplifier 111. By compensating the non-inverting input terminal and the inverting input terminal of the operational amplifier 111, the temperature drift coefficient is reduced. As an example, the temperature compensation module 12 includes a fourth amplifier transistor M4, a third transistor Q3, a fifth resistor R5, and a sixth resistor R6. The first end of the fourth amplifier transistor M4 is connected to the first ends of the first amplifier transistor M1, the second amplifier transistor M2, and the third amplifier transistor M3 (i.e., the power supply voltage VDD), and the second end is connected via the third transistor Q3 to the second ends of the first transistor Q1 and the second transistor Q2 (i.e., reference ground GND). One end of the fifth resistor R5 is connected to the second end of the fourth amplifier transistor M4, and the other end is connected to the first input terminal (or the second input terminal) of the operational amplifier 111. One end of the sixth resistor R6 is connected to the second end of the fourth amplifier transistor M4, and the other end is connected to the second input terminal (or the first input terminal) of the operational amplifier 111. The third transistor Q3 is the same as the first transistor Q1 (same type and size). The resistance values ​​of the fifth resistor R5 and the sixth resistor R6 are equal.

[0055] It should be noted that in practical use, any circuit structure that can achieve temperature compensation is applicable to this invention, and is not limited to this embodiment.

[0056] More specifically, in this embodiment, the current I4 flowing through the fourth amplifying transistor M4 is equal to the current I3 flowing through the third amplifying transistor M3. The resistance values ​​of the fifth resistor R5 and the sixth resistor R6 are set to 1 / 6 to 1 / 8 of the resistance value of the first resistor R1. In actual use, the resistance values ​​of the fifth resistor R5 and the sixth resistor R6 can be configured as needed to achieve temperature compensation, which will not be elaborated here.

[0057] Based on the above structural analysis, due to the "virtual short" characteristic of the operational amplifier 111, the voltages at the non-inverting and inverting input terminals of the operational amplifier 111 are equal (V1 = V2). Furthermore, the first amplifying transistor M1 and the second amplifying transistor M2 have the same gate-source voltage. Therefore, the current flowing through the first amplifying transistor M1 is equal to the current flowing through the second amplifying transistor M2, i.e., I1 = I2. The base-emitter voltage V of the first transistor Q1... BE It is inversely proportional to absolute temperature (CTAT) and satisfies: V BE =V T ·ln(Ic / Is), V T = k·T / q, where Ic is the collector current, Is is the saturation current, k is the Boltzmann constant, T is the temperature, and q is the electron charge; the difference ΔV between the base-emitter voltages of the first transistor Q1 and the second transistor Q2. BE It is proportional to absolute temperature (PTAT) and satisfies: ΔV BE =V T ·lnN. A current I with a negative temperature coefficient is generated in the branch containing the first resistor R1 and the branch containing the second resistor R2. C1 =I C2 =V BE(Q1) / R2 generates a current I with a positive temperature coefficient in the branch containing the first transistor Q1 and the branch containing the fourth resistor R4. P1 =I P2 =V T ·ln N / R4, then add the current in the branch containing the second resistor R2 to the DC current in the branch containing the fourth resistor R4 to get I2=V BE(Q1) / R2+V T By selecting appropriate values ​​for the second resistor R2 and the fourth resistor R4, a zero-temperature coefficient current I2 can be obtained. This current is replicated (or proportionally replicated) to the branch containing the third amplifying transistor M3 to obtain a zero-temperature coefficient current I3. Then, by adjusting the value of the third resistor R3, the desired bandgap reference voltage Vref is obtained. At this point, if the amplification factors of the first transistor Q1 and the second transistor Q2 are relatively small, the temperature drift coefficient of the obtained bandgap reference voltage can only reach above 15ppm.

[0058] Based on this, further compensation is performed using the temperature compensation module 12. A nonlinear compensation voltage can be obtained based on the difference between the base-emitter voltages of the first transistor Q1 and the third transistor Q3, satisfying the following: T r Using the reference temperature as a reference, the nonlinear compensation current is obtained, wherein the nonlinear compensation current of the branch containing the fifth resistor R5 satisfies: The nonlinear compensation current of the branch containing the sixth resistor R6 satisfies: The two are equal. After compensation by the temperature compensation module 12, the temperature drift coefficient is reduced by approximately 3–8 ppm.

[0059] This invention further introduces resistance compensation. The first resistor R1 and the second resistor R2 are of the same type (affected by the same process influences and deviations) and both have a first temperature drift characteristic. The third resistor R3 and the fourth resistor R4 are of the same type and both have a second temperature drift characteristic. The temperature drift characteristic of the combination of the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor Q1 (the base-emitter voltage of the first transistor Q1 has a negative temperature coefficient, so the total temperature drift characteristic exhibited by the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4 in the circuit structure of this invention has a positive temperature coefficient). The temperature drift coefficient is further reduced through the complementarity and cancellation of temperature drift characteristics. When the temperature compensation module 12 is configured, the temperature drift characteristics of the fifth resistor R5 and the sixth resistor R6 are consistent with the temperature drift characteristics of the first resistor R1 and the second resistor R2, i.e., both are the first temperature drift characteristics. The temperature drift characteristics of the combination of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, and the sixth resistor R6 are opposite to the temperature drift characteristics of the base-emitter voltage of the first transistor Q1. As an example, the first temperature drift characteristic is a negative temperature drift characteristic, and the second temperature drift characteristic is a positive temperature drift characteristic; as another example, the first temperature drift characteristic is a positive temperature drift characteristic, and the second temperature drift characteristic is a negative temperature drift characteristic; as yet another example, both the first temperature drift characteristic and the second temperature drift characteristic are either positive or negative temperature drift characteristics; the configuration can be adjusted according to actual needs, ensuring that the temperature drift characteristics of the combination of each resistor are opposite to the temperature drift characteristics of the base-emitter voltage of the first transistor Q1. As a specific embodiment of the present invention, the bandgap reference circuit 1 is fabricated using a 40nm or 50nm eflash process. The first resistor R1, the second resistor R2, the fifth resistor R5, and the sixth resistor R6 are RNPPO_LP type resistors with a first temperature drift characteristic, and the third resistor R3 and the fourth resistor R4 are RNNPO_LP type resistors with a second temperature drift characteristic. After resistor compensation, the temperature drift coefficient of the bandgap reference voltage Vref obtained by the present invention can be less than or equal to 5ppm (including but not limited to 4ppm, 3ppm, and 2ppm), achieving extremely low temperature drift.

[0060] This embodiment also provides an electronic product, which includes at least the bandgap reference circuit 1 of this embodiment. The bandgap reference circuit 1 of this invention is applicable to industrial measuring instruments, high-precision ADCs, and other devices. The electronic product includes, but is not limited to, chips, mobile phones, and computers. Any physical object that requires a bandgap reference circuit is suitable for this invention.

[0061] Example 2

[0062] like Figure 2 As shown, this embodiment also provides a bandgap reference circuit 1, which differs from the first embodiment in that the first amplifying transistor M1, the second amplifying transistor M2 and the third amplifying transistor M3 are NMOS transistors, and the circuit connection relationship is adjusted accordingly.

[0063] Specifically, the first source terminals of the first amplifier transistor M1, the second amplifier transistor M2, and the third amplifier transistor M3 are grounded to GND. The second drain terminal of the first amplifier transistor M1 is connected to the power supply voltage VDD via the first resistor R1. The second drain terminal of the second amplifier transistor M2 is connected to the power supply voltage VDD via the second resistor R2. The second drain terminal of the third amplifier transistor M3 outputs a bandgap reference voltage Vref and is connected to the power supply voltage VDD via the third resistor R3. The control terminal (gate) of each amplifier transistor is connected to the output terminal of the operational amplifier 111. The second terminal of the first amplifier transistor M1 is connected to the first input terminal of the operational amplifier 111, and the second terminal of the second amplifier transistor M2 is connected to the second input terminal of the operational amplifier 111. The first transistor Q1 is connected as a diode, with its first terminal connected to the first input terminal of the operational amplifier 111 and its second terminal connected to the power supply voltage VDD. The second transistor Q2 is connected as a diode, with its first terminal connected to the second input terminal of the operational amplifier 111 via the fourth resistor R4 and its second terminal connected to the power supply voltage VDD.

[0064] More specifically, the first transistor Q1 and the second transistor Q2 are implemented using NPN transistors. Correspondingly, the first terminal of the first transistor Q1 and the second transistor Q2 is the emitter, and the base and collector are connected together as the second terminal connected to the power supply voltage VDD. In practical applications, any device and structure capable of temperature sensing based on a PN junction is applicable to this invention, including but not limited to NPN transistors, PNP transistors, NMOS transistors, or PMOS transistors, which will not be elaborated upon here.

[0065] Accordingly, the third transistor Q3 is an NPN transistor, and the fourth amplifier transistor M4 is an NMOS transistor. The specific connection relationship will not be described in detail here.

[0066] The other structures and working principles of the bandgap reference circuit 1 in this embodiment are the same as those in Embodiment 1, and will not be described in detail here.

[0067] This embodiment also provides an electronic product, which includes at least the bandgap reference circuit 1 of this embodiment. The bandgap reference circuit 1 of this invention is applicable to industrial measuring instruments, high-precision ADCs, and other devices. The electronic product includes, but is not limited to, chips, mobile phones, and computers, which will not be described in detail here.

[0068] Example 3

[0069] This embodiment provides a method for adjusting a bandgap reference circuit, including:

[0070] S1) Provide a bandgap reference circuit 1 according to Embodiment 1 or Embodiment 2, wherein the preset bandgap reference voltage of the bandgap reference circuit 1 is a first value Vref1; generate an actual bandgap reference voltage based on the bandgap reference circuit 1, wherein the actual bandgap reference voltage is a second value Vref2; obtain a trimming ratio TR based on the first value Vref1 and the second value Vref2, wherein the trimming ratio satisfies:

[0071]

[0072] Specifically, the preset bandgap reference voltage is set according to the required bandgap reference voltage, and the parameters of each device in the bandgap reference circuit 1 are configured. Theoretically, the bandgap reference voltage output by the bandgap reference circuit 1 is the value of the preset bandgap reference voltage. However, due to errors and other reasons, the actual bandgap reference voltage obtained will deviate from the preset bandgap reference voltage. As an example, assuming the preset bandgap reference voltage is 1V and the actual bandgap reference voltage is 0.95V, that is, the first value Vref1 equals 1, the second value Vref2 equals 0.95, and the corresponding adjustment ratio TR equals 1 / 0.95.

[0073] S2) Adjust the third resistor R3 and / or the fourth resistor R4 so that the resistance values ​​of the third resistor R3 and / or the fourth resistor R4 satisfy the following:

[0074] R3a=R3b·TR; R4a=R4b·TR;

[0075] Wherein, R3a is the resistance value of the third resistor R3 after adjustment, R3b is the resistance value of the third resistor R3 before adjustment, R4a is the resistance value of the fourth resistor R4 after adjustment, and R4b is the resistance value of the fourth resistor R4 before adjustment.

[0076] Specifically, in this embodiment, the third resistor R3 and the fourth resistor R4 are adjusted to achieve a lower temperature drift, such as 2 ppm or even less. Since the third resistor R3 and the fourth resistor R4 are of the same type, they are subjected to the same process influences and deviations. The third resistor R3 is directly characterized by the output bandgap reference voltage Vref, and its adjustment value can be easily obtained by measuring the change in the bandgap reference voltage Vref. The adjustment value of the fourth resistor R4 is entirely characterized by the third resistor R3. Therefore, this invention only requires measuring the bandgap reference voltage Vref to determine the adjustment values ​​of the third resistor R3 and the fourth resistor R4, making adjustment very easy and suitable for application in mass-produced chips. In this example, the third resistor R3 is adjusted to 1 / 0.95 times its original value; similarly, the fourth resistor R4 is also adjusted to 1 / 0.95 times its original value.

[0077] In summary, this invention provides an electronic product, a bandgap reference circuit, and a method for adjusting the same, comprising: a bandgap reference voltage generation module and a temperature compensation module. The temperature compensation module provides temperature compensation for the bandgap reference voltage generation module, thereby reducing the temperature drift coefficient of the bandgap reference voltage generation module. The bandgap reference voltage generation module is a current-mode structure, comprising a first resistor, a second resistor, a third resistor, a fourth resistor, a first transistor, a second transistor, a first amplifying transistor, a second amplifying transistor, a third amplifying transistor, and an operational amplifier. The first amplifying transistor, the second amplifying transistor, and the third amplifying transistor constitute a current mirror structure. The first resistor and the second resistor are of the same type and both have a first temperature drift characteristic. The third resistor and the fourth resistor are of the same type and both have a second temperature drift characteristic. The temperature drift characteristic of the combination of the first resistor, the second resistor, the third resistor, and the fourth resistor is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor. The electronic product and bandgap reference circuit of this invention achieve ultra-low temperature drift characteristics through a temperature compensation module and complementary resistors, while also consuming little power. Furthermore, because this invention employs resistor-based temperature drift compensation, the adjustment process is greatly simplified, making it suitable for mass-produced chips. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and possesses high industrial applicability.

[0078] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A bandgap reference circuit, characterized in that, The bandgap reference circuit includes at least: A bandgap reference voltage generation module and a temperature compensation module, wherein the temperature compensation module provides temperature compensation for the bandgap reference voltage generation module, thereby reducing the temperature drift coefficient of the bandgap reference voltage generation module; The bandgap reference voltage generation module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first transistor, a second transistor, a first amplifying tube, a second amplifying tube, a third amplifying tube, and an operational amplifier. The first amplifying tube, the second amplifying tube, and the third amplifying tube constitute a current mirror structure. The first, second, and third amplifying transistors are connected to a power supply voltage at their first ends. The second end of the first amplifying transistor is grounded via a first resistor, the second end of the second amplifying transistor is grounded via a second resistor, and the second end of the third amplifying transistor outputs a bandgap reference voltage and is grounded via a third resistor. The control terminal of each amplifying transistor is connected to the output terminal of the operational amplifier. The second end of the first amplifying transistor is connected to the first input terminal of the operational amplifier, and the second end of the second amplifying transistor is connected to the second input terminal of the operational amplifier. The first transistor is connected as a diode, with its first end connected to the first input terminal of the operational amplifier and its second end grounded. The second transistor is connected as a diode, with its first end connected to the second input terminal of the operational amplifier via a fourth resistor and its second end grounded. The first resistor and the second resistor are of the same type and both have a first temperature drift characteristic; the third resistor and the fourth resistor are of the same type and both have a second temperature drift characteristic; the temperature drift characteristic of the combination of the first resistor, the second resistor, the third resistor and the fourth resistor is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor.

2. The bandgap reference circuit according to claim 1, characterized in that: The first amplifying transistor, the second amplifying transistor, and the third amplifying transistor are PMOS transistors.

3. A bandgap reference circuit, characterized in that, The bandgap reference circuit includes at least: A bandgap reference voltage generation module and a temperature compensation module, wherein the temperature compensation module provides temperature compensation for the bandgap reference voltage generation module, thereby reducing the temperature drift coefficient of the bandgap reference voltage generation module; The bandgap reference voltage generation module includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first transistor, a second transistor, a first amplifying tube, a second amplifying tube, a third amplifying tube, and an operational amplifier. The first amplifying tube, the second amplifying tube, and the third amplifying tube constitute a current mirror structure. The first, second, and third amplifying transistors have their first terminals grounded. The second terminal of the first amplifying transistor is connected to the power supply voltage via the first resistor. The second terminal of the second amplifying transistor is connected to the power supply voltage via the second resistor. The second terminal of the third amplifying transistor outputs a bandgap reference voltage and is connected to the power supply voltage via the third resistor. The control terminal of each amplifying transistor is connected to the output terminal of the operational amplifier. The second terminal of the first amplifying transistor is connected to the first input terminal of the operational amplifier. The second terminal of the second amplifying transistor is connected to the second input terminal of the operational amplifier. The first transistor is connected as a diode, with its first terminal connected to the first input terminal of the operational amplifier and its second terminal connected to the power supply voltage. The second transistor is connected as a diode, with its first terminal connected to the second input terminal of the operational amplifier via the fourth resistor and its second terminal connected to the power supply voltage. The first resistor and the second resistor are of the same type and both have a first temperature drift characteristic; the third resistor and the fourth resistor are of the same type and both have a second temperature drift characteristic; the temperature drift characteristic of the combination of the first resistor, the second resistor, the third resistor and the fourth resistor is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor.

4. The bandgap reference circuit according to claim 3, characterized in that: The first amplifying transistor, the second amplifying transistor, and the third amplifying transistor are NMOS transistors.

5. The bandgap reference circuit according to any one of claims 1-4, characterized in that: The first transistor and the second transistor are NPN transistors, PNP transistors, NMOS transistors, or PMOS transistors.

6. The bandgap reference circuit according to any one of claims 1-4, characterized in that: The first temperature drift characteristic is a negative temperature drift characteristic, and the second temperature drift characteristic is a positive temperature drift characteristic; or, the first temperature drift characteristic is a positive temperature drift characteristic, and the second temperature drift characteristic is a negative temperature drift characteristic.

7. The bandgap reference circuit according to any one of claims 1-4, characterized in that: The temperature compensation module includes a fourth amplifying tube, a third transistor, a fifth resistor, and a sixth resistor; The first end of the fourth amplifying transistor is connected to the first amplifying transistor, the second amplifying transistor and the first end of the third amplifying transistor, and the second end is connected to the second end of the first transistor and the second transistor via the third transistor. One end of the fifth resistor is connected to the second end of the fourth amplifier tube, one end of the sixth resistor is connected to the second end of the fourth amplifier tube, and the other ends of the fifth resistor and the sixth resistor are respectively connected to the input terminals of the operational amplifier. The third transistor is the same as the first transistor; the fifth resistor and the sixth resistor have the same resistance value, are of the same type as the first resistor and the second resistor, and all have the first temperature drift characteristic. The temperature drift characteristic of the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor and the sixth resistor combined is opposite to the temperature drift characteristic of the base-emitter voltage of the first transistor.

8. The bandgap reference circuit according to claim 7, characterized in that: The resistance value of the fifth resistor is set to 1 / 6 to 1 / 8 of the resistance value of the first resistor.

9. The bandgap reference circuit according to any one of claims 1-4, characterized in that: The bandgap reference circuit is fabricated using a 40nm or 50nm eflash process.

10. The bandgap reference circuit according to any one of claims 1-4, characterized in that: The temperature drift coefficient of the bandgap reference circuit is less than or equal to 5 ppm.

11. A method for adjusting a bandgap reference circuit, characterized in that, The adjustment method for the bandgap reference circuit includes at least the following: A bandgap reference circuit as described in any one of claims 1-10 is provided, wherein the preset bandgap reference voltage of the bandgap reference circuit is a first value; an actual bandgap reference voltage is generated based on the bandgap reference circuit, wherein the actual bandgap reference voltage is a second value; and a trimming ratio is obtained based on the first value and the second value, wherein the trimming ratio satisfies: ； Adjust the third resistor and / or the fourth resistor so that their resistance values ​​satisfy: ； ； Where TR is the adjustment ratio. The first value is... R3a is the adjusted resistance value of the third resistor, R3b is the original resistance value of the third resistor, R4a is the adjusted resistance value of the fourth resistor, and R4b is the original resistance value of the fourth resistor.

12. An electronic product, characterized in that, The electronic product includes at least the bandgap reference circuit as described in any one of claims 1-10.

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