A low-temperature drift bipolar bandgap voltage reference

Abstract

The application belongs to the field of analog integrated circuits, and discloses a bipolar bandgap reference voltage source with low temperature drift, which comprises a bandgap reference module, a temperature compensation module and a direct current biasing module; the temperature compensation module is connected with the bandgap reference module, and the direct current biasing module is connected with the bandgap reference module and the temperature compensation module; the bandgap reference module is used for generating a first-order compensated bandgap reference voltage; the temperature compensation module is used for generating a high-order PTAT current, and compensating a high-order term of a negative temperature coefficient in the bandgap reference voltage through the high-order PTAT current, so as to obtain a bandgap reference voltage with low temperature drift; and the direct current biasing module is used for generating a first biasing current and a second biasing current, and sending the first biasing current and the second biasing current to the bandgap reference module and the temperature compensation module respectively. The circuit can make the reference voltage output by the bandgap reference voltage source not change with temperature in different temperature working states, has the characteristics of low temperature drift and adaptation to bipolar technology, and improves the application applicability of the reference voltage source circuit.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of analog integrated circuits, and relates to a bipolar bandgap reference voltage source with low temperature drift. BACKGROUND

[0002] In recent years, with the continuous development and upgrading of electronic products, the performance requirements for integrated circuit chips are becoming higher and higher. As an important part of systems such as digital-to-analog converters, analog-to-digital converters and switching power supplies, the bandgap reference voltage source has the characteristics of high precision, low temperature drift and stability, and can provide a stable voltage for the system that is not affected by power supply voltage, working temperature and process parameters.

[0003] The existing bandgap reference voltage source uses the base-emitter voltage VBE with a negative temperature coefficient to superimpose the N·Vt structure with a positive temperature coefficient, lacks a temperature compensation structure, cannot eliminate the high-order influence of temperature on the output reference voltage, and the output reference voltage is obviously affected by temperature changes, which is not conducive to the selection and design of system-level users. SUMMARY

[0004] The application aims to overcome the shortcomings of the prior art that the existing bandgap reference voltage source cannot eliminate the high-order influence of temperature on the output reference voltage, and the output reference voltage is obviously affected by temperature changes, and provides a bipolar bandgap reference voltage source with low temperature drift.

[0005] To achieve the above-mentioned purpose, the application adopts the following technical solutions:

[0006] A bipolar bandgap reference voltage source with low temperature drift comprises a bandgap reference module, a temperature compensation module and a direct current bias module; the temperature compensation module is connected with the bandgap reference module, and the direct current bias module is connected with the bandgap reference module and the temperature compensation module; the bandgap reference module is used to generate a first-order compensated bandgap reference voltage; the temperature compensation module is used to generate a high-order PTAT current, and compensate the high-order term of the negative temperature coefficient in the bandgap reference voltage through the high-order PTAT current to obtain a bandgap reference voltage with low temperature drift; and the direct current bias module is used to generate a first bias current and a second bias current, and send them to the bandgap reference module and the temperature compensation module respectively.

[0007] Optionally, the bandgap reference module comprises a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, a first resistor R1, a second resistor R2 and a third resistor R3; a first end of the third resistor R3 is provided as a first output node, and a second end thereof is connected to a first end of the second resistor R2; a second end of the second resistor R2 is connected to an emitter of the first transistor Q1 and an emitter of the second transistor Q2; a second output node is provided on a base of the first transistor Q1, and the base is connected to a base of the second transistor Q2; a collector of the first transistor Q1 is connected to a collector of the third transistor Q3; a collector of the second transistor Q2 is connected to a collector of the fourth transistor Q4; a base of the third transistor Q3 is connected to a base of the fourth transistor Q4; the base of the fourth transistor Q4 is short-circuited with the collector thereof, and an emitter thereof is connected to a first end of the first resistor R1.

[0008] Optionally, the emitter of the third transistor Q3 is grounded; and a second end of the first resistor R1 is grounded.

[0009] Optionally, a ratio of areas of the emitter regions of the third transistor Q3 and the fourth transistor Q4 is 1:8.

[0010] Optionally, the temperature compensation module comprises a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8, a ninth transistor Q9, a tenth transistor Q10, an eleventh transistor Q11, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6; an emitter of the sixth transistor Q6 is connected to the first output node, a collector thereof is connected to the first end of the second resistor R2, and a base thereof is connected to a base of the seventh transistor Q7; an emitter of the seventh transistor Q7 is connected to the first output node, and a collector thereof is short-circuited with the base thereof; a collector of the ninth transistor Q9 is connected to the collector of the seventh transistor Q7, a base thereof is connected to a second end of the fifth resistor R5, and an emitter thereof is connected to a first end of the fourth resistor R4; a collector of the eighth transistor Q8 is connected to the first output node, a base thereof is connected to a base of the tenth transistor Q10, and an emitter thereof is connected to the first end of the fourth resistor R4; a collector of the tenth transistor Q10 is short-circuited with the base thereof, and an emitter thereof is connected to a collector of the eleventh transistor Q11; a base of the eleventh transistor Q11 is short-circuited with the collector thereof; a first end of the fifth resistor R5 is connected to the base of the eighth transistor Q8, and a second end thereof is connected to a first end of the sixth resistor R6; a second end of the sixth resistor R6 is connected to the emitter of the tenth transistor Q10.

[0011] Optionally, a second end of the fourth resistor R4 is grounded; and an emitter of the eleventh transistor Q11 is grounded.

[0012] Optionally, 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 all polysilicon resistors.

[0013] Optionally, the emitter area ratio of the sixth transistor Q6 and the seventh transistor Q7 is 1:1; the emitter area ratio of the eighth transistor Q8, the ninth transistor Q9, the tenth transistor Q10 and the eleventh transistor Q11 is 1:1:2:2.

[0014] Optionally, the DC bias module includes a fifth transistor Q5, a first current source I1, a second current source I2 and a third current source I3; the base of the fifth transistor Q5 is connected to the first end of the third current source I3, and the collector is connected to the first output node; the first end of the first current source I1 is connected to the collector of the tenth transistor Q10; and the first end of the second current source I2 is connected to the second output node.

[0015] Optionally, the emitter of the fifth transistor Q5 , the second end of the first current source I1 , the second end of the second current source I2 , and the second end of the third current source I3 are all connected to the power supply VCC.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention discloses a low-temperature drift bipolar bandgap reference voltage source comprising a bandgap reference module, a temperature compensation module, and a DC bias module. The bandgap reference module provides a first-order compensated bandgap reference voltage, the temperature compensation module provides a high-order PTAT current, and the high-order PTAT current compensates for the high-order terms of the negative temperature coefficient in the bandgap reference voltage to obtain a low-temperature drift bandgap reference voltage. The DC bias module provides a DC bias for the bandgap reference module and the temperature compensation module. The bipolar bandgap reference voltage source can operate under different temperature conditions. Based on the varying high-order PTAT current generated by the temperature compensation module, the output bandgap reference voltage is unaffected by temperature changes. The bipolar bandgap reference voltage source exhibits low temperature drift and is adaptable to bipolar processes. This improves the applicability of the reference voltage source circuit and can be widely used in various power management and driver chips, offering promising application prospects and economic benefits. The invention effectively addresses the drawback of existing bandgap reference structures, which, due to the lack of a temperature compensation structure, cannot eliminate the high-order effects of temperature on the output bandgap reference voltage, resulting in the output bandgap reference voltage being significantly affected by temperature changes, hindering system-level user selection and design. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the structure of an existing bandgap reference voltage source.

[0019] Figure 2 The figure is a schematic structural diagram of a low-temperature drift bipolar bandgap reference voltage source according to the present invention.

[0020] Figure 3 This is a temperature characteristic curve diagram of the temperature-compensated reference voltage of the present invention. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0022] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0023] The present invention is described in further detail below with reference to the accompanying drawings:

[0024] See also Figure 1 Existing bandgap reference voltage sources usually use a base-emitter voltage VBE with a negative temperature coefficient superimposed on a positive temperature coefficient N·Vt. They lack a temperature compensation structure and cannot eliminate the high-order effects of temperature on the output bandgap reference voltage. The output bandgap reference voltage is significantly affected by temperature changes, which is not conducive to the selection and design of system-level users.

[0025] See also Figure 2 The present invention provides a low-temperature drift bipolar bandgap reference voltage source, which has a simple circuit structure design, and has the characteristics of low temperature drift, high reliability, adaptability to bipolar processes, small chip area and low cost, thereby improving the application applicability of the reference voltage source circuit.

[0026] Specifically, the low-temperature drift bipolar bandgap reference voltage source includes a bandgap reference module, a temperature compensation module and a DC bias module; the temperature compensation module is connected to the bandgap reference module, and the DC bias module is connected to both the bandgap reference module and the temperature compensation module; the bandgap reference module is used to generate a first-order compensated bandgap reference voltage; the temperature compensation module is used to generate a high-order PTAT current, and compensate for the high-order terms of the negative temperature coefficient in the bandgap reference voltage through the high-order PTAT current to obtain a low-temperature drift bandgap reference voltage; the DC bias module is used to generate a first bias current and a second bias current, and send them to the bandgap reference module and the temperature compensation module respectively.

[0027] The bandgap reference module includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4, and a first resistor R1, a second resistor R2, and a third resistor R3; a first end of the third resistor R3 is provided with a first output node A, and a second end is connected to the first end of the second resistor R2; a second end of the second resistor R2 is connected to the emitter of the first transistor Q1 and the emitter of the second transistor Q2; a second output node B is provided on the base of the first transistor Q1 and is connected to the base of the second transistor Q2; the collector of the first transistor Q1 is connected to the collector of the third transistor Q3; the collector of the second transistor Q2 is connected to the collector of the fourth transistor Q4; the base of the third transistor Q3 is connected to the base of the fourth transistor Q4; the base and collector of the fourth transistor Q4 are short-circuited, and the emitter is connected to the first end of the first resistor R1.

[0028] The bandgap reference module uses the first transistor Q1, the second transistor Q2, the third transistor Q3, the fourth transistor Q4 and the first resistor R1 to generate a current positively correlated with temperature (i.e., PTAT current), uses the second resistor R2 and the third resistor R3 to generate a PTAT voltage, and uses the base-emitter voltage VBE of the first transistor Q1 superimposed on the PTAT voltage to generate a first-order compensated bandgap reference voltage.

[0029] The temperature compensation module includes a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8, a ninth transistor Q9, a tenth transistor Q10, an eleventh transistor Q11, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6; the emitter of the sixth transistor Q6 is connected to the first output node A, the collector is connected to the first end of the second resistor R2, and the base is connected to the base of the seventh transistor Q7; the emitter of the seventh transistor Q7 is connected to the first output node A, the collector and the base are short-circuited; the collector of the ninth transistor Q9 is connected to the collector of the seventh transistor Q7, and the base is connected to the fifth transistor The second end of the resistor R5 and the emitter are connected to the first end of the fourth resistor R4; the collector of the eighth transistor Q8 is connected to the first output node A, the base is connected to the base of the tenth transistor Q10, and the emitter is connected to the first end of the fourth resistor R4; the collector and base of the tenth transistor Q10 are short-circuited, and the emitter is connected to the collector of the eleventh transistor Q11; the base and collector of the eleventh transistor Q11 are short-circuited; the first end of the fifth resistor R5 is connected to the base of the eighth transistor Q8, and the second end is connected to the first end of the sixth resistor R6; the second end of the sixth resistor R6 is connected to the emitter of the tenth transistor Q10.

[0030] The temperature compensation module uses the eighth transistor Q8, the ninth transistor Q9, the tenth transistor Q10, the eleventh transistor Q11, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 to generate a high-order PTAT current. The high-order PTAT current acts on the third resistor R3 through the mirror image of the sixth transistor Q6 and the seventh transistor Q7, and is used to compensate for the high-order term of the negative temperature coefficient in the base-emitter voltage VBE of the second transistor Q2, so that the bandgap reference voltage output after compensation obtains a low temperature drift characteristic.

[0031] The DC bias module includes a fifth transistor Q5, a first current source I1, a second current source I2 and a third current source I3; the base of the fifth transistor Q5 is connected to the first end of the third current source I3, and the collector is connected to the first output node A; the first end of the first current source I1 is connected to the collector of the tenth transistor Q10; and the first end of the second current source I2 is connected to the second output node B.

[0032] The second current source I2 and the third current source I3 in the DC bias module provide bias current for the fifth transistor Q5, the first transistor Q1, and the second transistor Q2. The third current source I3 provides DC bias for the temperature compensation module, and the fifth transistor Q5 provides DC bias for the bandgap reference module.

[0033] When in use, the emitter of the third transistor Q3 is grounded; the second end of the first resistor R1 is grounded, and the second end of the fourth resistor R4 is grounded; the emitter of the eleventh transistor Q11 is grounded, and the emitter of the fifth transistor Q5, the second end of the first current source I1, the second end of the second current source I2, and the second end of the third current source I3 are all connected to the power supply VCC.

[0034] In summary, the existing bandgap reference structure does not include a temperature compensation structure, which cannot eliminate the high-order influence of temperature on the output reference voltage. The output reference voltage is significantly affected by temperature changes, which is not conducive to the selection and design of system-level users. The temperature compensation structure adopted by the present invention allows the circuit to generate a variable high-order PTAT compensation current under different operating conditions of the circuit, so that the bandgap reference voltage output by the bandgap reference voltage source is not affected by temperature changes. It has the characteristics of low temperature drift and adaptability to bipolar processes, improves the application applicability of the bandgap reference voltage source circuit, and can be widely used in various power management and drive chips, with good application prospects and economic benefits.

[0035] Optionally, assuming that the emitter area ratio of the third transistor Q3 to the emitter area of ​​the fourth transistor Q4 is 1:N, the base-emitter voltage difference ΔV between the third transistor Q3 and the fourth transistor Q4 is BE The relationship is: ΔV BE =V BE3 -V BE4 =V T lnN, where V T is the thermal voltage, proportional to the temperature T,

[0036] ΔV BE Acting on the first resistor R1, generating PTAT current I PTAT : The current flowing through the first resistor R1 and the second resistor R2 is twice I PTAT .

[0037] The bandgap reference voltage relationship is as follows:

[0038]

[0039] Optionally, in this embodiment, N is designed to be 8, the first resistor R1 is a polysilicon resistor with a resistance of 52 kΩ, the second resistor R2 is a polysilicon resistor with a resistance of 138 kΩ, and the third resistor R3 is a polysilicon resistor with a resistance of 98 kΩ.

[0040] Optionally, it is assumed that the emitter area ratio of the sixth transistor Q6 and the seventh transistor Q7 is 1:1; and the emitter area ratio of the eighth transistor Q8, the ninth transistor Q9, the tenth transistor Q10 and the eleventh transistor Q11 is 1:1:2:2.

[0041] When the circuit works at low temperature, the base-emitter voltage of the tenth transistor Q10 is less than the turn-on voltage of the transistor, and the tenth transistor Q10 is in the off state. The bias current I1 flows through the fifth resistor R5, the sixth resistor R6 and the eleventh transistor Q11 to the ground. The collector current of the ninth transistor Q9 and the eighth transistor Q8 satisfies: The collector current flowing through the eleventh transistor Q11, the ninth transistor Q9 and the eighth transistor Q8 satisfies:

[0042] With the increase of the working temperature of the circuit, the current flowing through the fifth resistor R5 and the sixth resistor R6 gradually increases, and the turn-on voltage of the tenth transistor Q10 decreases, and the tenth transistor Q10 will be turned on. The bias current I1 flows through the tenth transistor Q10 and the eleventh transistor Q11 to the ground, so the current flowing through the fifth resistor R5 and the sixth resistor R6 decreases. The collector current of the eleventh transistor Q11, the ninth transistor Q9 and the eighth transistor Q8 still satisfies: The collector current of the ninth transistor Q9 and the eighth transistor Q8 satisfies:

[0043] According to the above, it can be seen that the compensation current I C9 is a positive temperature coefficient current containing a high-order term lnT. The reference voltage value output by the compensated circuit satisfies:

[0044] In the embodiment, the fourth resistor R4 is a polysilicon resistor with a resistance of 90kΩ, the fifth resistor R5 is a polysilicon resistor with a resistance of 19.5kΩ, and the sixth resistor R6 is a polysilicon resistor with a resistance of 212kΩ.

[0045] Referring to Figure 3 , the simulation results of the circuit of the low-temperature-drift bipolar bandgap reference voltage source in the embodiment show that, when the temperature of the circuit is scanned in the temperature range of-55℃ to 125℃, the simulation value of the output voltage of the bandgap reference is 1.202V, the change amplitude of the output reference voltage with the temperature is 3.052mV, the temperature drift is 14ppm / ℃, and the circuit has good temperature characteristics.

[0046] According to the above description, it can be seen that the temperature compensation structure of the low-temperature-drift bipolar bandgap reference voltage source can generate a high-order PTAT compensation current that changes under different working temperatures of the circuit, so that the reference voltage output by the bandgap reference voltage source is not affected by the temperature, and the low-temperature-drift bipolar bandgap reference voltage source has the characteristics of low temperature drift and adaptation to bipolar technology, improves the application applicability of the reference voltage source circuit, and can be widely applied in various power management and driving chips, and has good application prospect and economic benefit.

[0047] The above content is only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A low-temperature drift bipolar bandgap reference voltage source, characterized in that: It includes a bandgap reference module, a temperature compensation module and a DC bias module; the temperature compensation module is connected to the bandgap reference module, and the DC bias module is connected to both the bandgap reference module and the temperature compensation module; The bandgap reference module is used to generate a first-order compensated bandgap reference voltage; The temperature compensation module is used to generate a high-order PTAT current and compensate the high-order term with a negative temperature coefficient in the bandgap reference voltage through the high-order PTAT current to obtain a bandgap reference voltage with a low temperature drift; The DC bias module is used to generate a first bias current and a second bias current, and send them to the bandgap reference module and the temperature compensation module respectively; The bandgap reference module includes a first transistor Q1, a second transistor Q2, a third transistor Q3, a fourth transistor Q4 and a first resistor R1, a second resistor R2 and a third resistor R3; a first end of the third resistor R3 is provided with a first output node, and a second end is connected to the first end of the second resistor R2; a second end of the second resistor R2 is connected to the emitter of the first transistor Q1 and the emitter of the second transistor Q2; a second output node is provided on the base of the first transistor Q1 and is connected to the base of the second transistor Q2; a collector of the first transistor Q1 is connected to the collector of the third transistor Q3; a collector of the second transistor Q2 is connected to the collector of the fourth transistor Q4; a base of the third transistor Q3 is connected to the base of the fourth transistor Q4; the base and collector of the fourth transistor Q4 are short-circuited, and the emitter is connected to the first end of the first resistor R1; The temperature compensation module includes a sixth transistor Q6, a seventh transistor Q7, an eighth transistor Q8, a ninth transistor Q9, a tenth transistor Q10, an eleventh transistor Q11, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6; the emitter of the sixth transistor Q6 is connected to the first output node, the collector is connected to the first end of the second resistor R2, and the base is connected to the base of the seventh transistor Q7; the emitter of the seventh transistor Q7 is connected to the first output node, the collector and the base are short-circuited; the collector of the ninth transistor Q9 is connected to the collector of the seventh transistor Q7, and the base is connected to the fifth transistor Q8. The second end and emitter of the resistor R5 are connected to the first end of the fourth resistor R4; the collector of the eighth transistor Q8 is connected to the first output node, the base is connected to the base of the tenth transistor Q10, and the emitter is connected to the first end of the fourth resistor R4; the collector and base of the tenth transistor Q10 are short-circuited, and the emitter is connected to the collector of the eleventh transistor Q11; the base and collector of the eleventh transistor Q11 are short-circuited; the first end of the fifth resistor R5 is connected to the base of the eighth transistor Q8, and the second end is connected to the first end of the sixth resistor R6; the second end of the sixth resistor R6 is connected to the emitter of the tenth transistor Q10; The DC bias module includes a fifth transistor Q5, a first current source I1, a second current source I2 and a third current source I3; the base of the fifth transistor Q5 is connected to the first end of the third current source I3, and the collector is connected to the first output node; the first end of the first current source I1 is connected to the collector of the tenth transistor Q10; and the first end of the second current source I2 is connected to the second output node.

2. The low-temperature drift bipolar bandgap reference voltage source according to claim 1, characterized in that: The emitter of the third transistor Q3 is grounded; the second end of the first resistor R1 is grounded.

3. The low-temperature drift bipolar bandgap reference voltage source according to claim 1, characterized in that: The emitter area ratio of the third transistor Q3 and the fourth transistor Q4 is 1:

8.

4. The low-temperature drift bipolar bandgap reference voltage source according to claim 1, characterized in that: The second end of the fourth resistor R4 is grounded; the emitter of the eleventh transistor Q11 is grounded.

5. The low-temperature drift bipolar bandgap reference voltage source according to claim 1, characterized in that: 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 all polysilicon resistors.

6. The low-temperature drift bipolar bandgap reference voltage source according to claim 1, characterized in that: The emitter area ratio of the sixth transistor Q6 and the seventh transistor Q7 is 1:1; the emitter area ratio of the eighth transistor Q8, the ninth transistor Q9, the tenth transistor Q10 and the eleventh transistor Q11 is 1:1:2:

2.

7. The low-temperature drift bipolar bandgap reference voltage source according to claim 1, characterized in that: The emitter of the fifth transistor Q5 , the second end of the first current source I1 , the second end of the second current source I2 , and the second end of the third current source I3 are all connected to the power source VCC.

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