CN104216459A - Bandgap reference voltage generating circuit and electronic system using it - Google Patents

Abstract

The invention discloses a band gap reference voltage generating circuit for providing reference voltage. The four-terminal current source circuit is electrically connected with the first system voltage, and when the first system voltage is greater than the threshold voltage value, the first voltage, the second voltage and the first current output by the four-terminal current source circuit are independent of the change of the first system voltage. The voltage stabilizing circuit receives the first voltage and the second voltage and outputs a reference voltage independent of the change of the first system voltage through a stable voltage difference between the first voltage and the second voltage when the first system voltage is greater than a threshold voltage value. The temperature compensation circuit receives the first current and compensates a temperature curve of the reference voltage output by the voltage regulator circuit.

Description

Bandgap reference voltage generating circuit and electronic system using it

technical field

The present invention relates to a bandgap reference voltage generation circuit, in particular to a bandgap reference voltage generation circuit independent of system voltage and temperature.

Background technique

With the continuous innovation and improvement of high technology, consumer electronic products have gradually become popular in people's lives, especially various handheld electronic devices, such as mobile phones, digital cameras, personal digital assistants or tablet computers, etc., because of their thinness and shortness, The feature of being portable is deeply loved by people. However, the use of handheld electronic devices must consider the length of power supply time. At present, battery devices such as nickel metal hydride batteries and lithium batteries are mostly used, and additionally used with a charger that meets the specifications of the battery device.

The design of bandgap reference voltage source circuits is well known in the art in the art. These circuits are designed to provide a voltage standard independent of temperature variations in the circuit. The reference voltage of the bandgap reference voltage source is the voltage V b e developed between the base and emitter of a bipolar bipolar junction transistor (bipolar transistor) and the bases of the other two bipolar transistors - A function of the difference (△V b e ) of the emitter voltage V b e. The base-emitter voltage V b e of the first bipolar transistor has a negative temperature coefficient, or the base-emitter voltage V b e will decrease as the temperature increases. The differential voltage ΔV be of the other two bipolar transistors will have a positive temperature coefficient, which means that the differential base-emitter voltage ΔV be increases as the temperature increases. The reference voltage is independent of the temperature of the bandgap voltage reference voltage source by scaling the differential base-emitter voltage ΔV b e and summing it with the base-emitter voltage V b e of the first bipolar transistor and get adjusted. However, general reference voltage generation circuits may encounter related problems that the stability of the reference voltage is affected by the change of the ambient temperature or the variation of the system voltage.

Contents of the invention

The object of the present invention is to provide a bandgap reference voltage generating circuit for providing a reference voltage. The bandgap reference voltage generating circuit includes a four-terminal current source circuit, a voltage stabilizing circuit and a temperature compensation circuit. The four-terminal current source circuit is electrically connected to the first system voltage. When the first system voltage is greater than the threshold voltage value, the first voltage, the second voltage and the first current output by the four-terminal current source circuit are independent of the first system voltage. Variety. The voltage stabilizing circuit is electrically connected to the four-terminal current source circuit. The voltage stabilizing circuit receives the first voltage and the second voltage and when the first system voltage is greater than the threshold voltage, passes the stable voltage between the first and second voltages. difference, the voltage stabilizing circuit outputs a reference voltage that is independent of changes in the first system voltage. The temperature compensation circuit is electrically connected to the four-terminal current source circuit and the voltage stabilization circuit. The temperature compensation circuit receives the first current and is used for compensating the temperature curve of the reference voltage output by the voltage stabilization circuit.

In one embodiment of the present invention, the temperature curve of the reference voltage output by the voltage stabilizing circuit is compensated so as to compensate the second-order temperature curve of the reference voltage into a third-order temperature curve.

In one embodiment of the present invention, when the first system voltage is greater than the threshold voltage, the four-terminal current source circuit outputs a stable first voltage and a second voltage, and outputs a stable first current.

In one embodiment of the present invention, the four-terminal current source circuit includes a first transistor, a second transistor and a first resistor. The drain of the first transistor is connected to the first system voltage. The drain of the second transistor is connected to the source of the first transistor, and the source of the second transistor is connected to the gate of the first transistor, wherein the first and second transistors are depletion transistors. One end of the first resistor is connected to the source of the second transistor, and the other end of the first resistor is connected to the gate of the second transistor. When the first system voltage is greater than the threshold voltage, the first transistor, the second transistor and the first The first current generated by the resistor is a stable current independent of the change of the first system voltage.

In one embodiment of the present invention, the voltage stabilizing circuit includes a third transistor and a fourth transistor. The drain of the third transistor is connected to the first system voltage, and the gate of the third transistor is connected to the gate of the first transistor to receive the first voltage. The drain of the fourth transistor is connected to the source of the third transistor, the gate of the fourth transistor is connected to the other end of the first resistor to receive the second voltage, the source of the fourth transistor is connected to the load resistor and outputs a reference voltage, wherein the third and the fourth transistor is a depletion transistor. The source voltage of the third transistor is locked at a stable voltage value through the stable first voltage, so that the reference voltage is locked at the first reference voltage value independent of the change of the first system voltage.

In one embodiment of the present invention, the voltage stabilizing circuit includes a fifth transistor and a sixth transistor. The drain of the fifth transistor is connected to the first system voltage, and the gate of the fifth transistor is connected to the source of the first transistor to receive the first voltage. The drain of the sixth transistor is connected to the source of the fifth transistor, the gate of the sixth transistor is connected to the gate of the first transistor to receive the second voltage, the source of the sixth transistor is connected to the load resistor and outputs a reference voltage, wherein the fifth and the sixth transistor is a depletion transistor, wherein the source voltage of the fifth transistor is locked at a stable voltage value through the stable first voltage, so that the reference voltage is locked at the first voltage independent of the change of the first system voltage. Reference voltage value.

In one embodiment of the present invention, the temperature compensation circuit includes a first bipolar transistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a second bipolar transistor, a sixth resistor and a third bipolar transistor . The emitter of the first bipolar transistor is connected to the ground voltage. One end of the second resistor is connected to the base of the first bipolar transistor. One end of the third resistor is connected to the other end of the second resistor, and the other end of the third resistor is connected to the collector of the first bipolar transistor. One end of the fourth resistor is connected to one end of the third resistor. One end of the fifth resistor is connected to the other end of the fourth resistor and connected to the source of the fourth transistor or the sixth transistor. The base of the second bipolar transistor is connected to the other end of the third resistor, and the collector of the second bipolar transistor is connected to the other end of the fifth resistor. One end of the sixth resistor is connected to the emitter of the second bipolar transistor, and the other end of the sixth resistor is connected to the ground voltage, wherein the first base-emitter voltage of the first bipolar transistor is connected to the second base emitter of the second bipolar transistor. The base-emitter voltage difference between the electrode voltages makes the second current flowing through the sixth resistor a current with a positive temperature coefficient. The base of the third bipolar transistor is connected to the collector of the second bipolar transistor, the emitter of the third bipolar transistor is connected to the ground voltage, the collector of the third bipolar transistor is connected to the other end of the first resistor, and the third Bipolar transistors have a third base-emitter voltage with a negative temperature coefficient. By adjusting the resistance values of the fifth resistor and the sixth resistor, the reference voltage is equal to or close to zero temperature coefficient voltage, and the first reference voltage value is equal to the sum of the voltage drop of the fifth resistor and the third base-emitter voltage.

In one embodiment of the present invention, the second-order temperature curve of the reference voltage is compensated to a third-order temperature curve by adjusting the resistance values of the second and third resistors.

In one embodiment of the present invention, the temperature compensation circuit further includes a seventh resistor. One end of the seventh resistor is connected to the base of the third bipolar transistor, and the other end of the seventh resistor is connected to the ground voltage, and the seventh resistor is used to raise the first reference voltage value of the reference voltage to the second reference voltage value, wherein The second reference voltage value of the reference voltage is equal to the sum of the voltage drop of the fifth resistor and the voltage drop of the seventh resistor

From another point of view, an embodiment of the present invention provides an electronic system, which includes a bandgap reference voltage generating circuit and a load. The bandgap reference voltage generating circuit includes a four-terminal current source circuit, a voltage stabilizing circuit and a temperature compensation circuit. The four-terminal current source circuit is electrically connected to the first system voltage. When the first system voltage is greater than the threshold voltage value, the first voltage, the second voltage and the first current output by the four-terminal current source circuit are independent of the first system voltage. Variety. The voltage stabilizing circuit is electrically connected to the four-terminal current source circuit. The voltage stabilizing circuit receives the first voltage and the second voltage and when the first system voltage is greater than the threshold voltage, passes the stable voltage between the first and second voltages. difference, the voltage stabilizing circuit outputs a reference voltage that is independent of changes in the first system voltage. The temperature compensation circuit is electrically connected to the four-terminal current source circuit and the voltage stabilization circuit. The temperature compensation circuit receives the first current and is used for compensating the temperature curve of the reference voltage output by the voltage stabilization circuit. The load is electrically connected to the bandgap reference voltage generating circuit to receive the reference voltage.

To sum up, the bandgap reference voltage generation circuit and electronic system proposed by the embodiments of the present invention enable the bandgap reference voltage generation circuit to provide an energy independent from the first system through a four-terminal current source circuit and a temperature compensation circuit. Reference voltage for voltage and temperature.

In order to enable a further understanding of the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings of the present invention, but these descriptions and accompanying drawings are only used to illustrate the present invention, rather than claiming the present invention any limitations on the scope.

Description of drawings

FIG. 1 is a schematic block diagram of a bandgap reference voltage generating circuit according to an embodiment of the present invention.

FIG. 2 is a specific circuit diagram of a bandgap reference voltage generating circuit according to an embodiment of the present invention.

FIG. 3 is a graph showing the temperature compensation effect of the bandgap reference voltage generating circuit according to an embodiment of the present invention.

FIG. 4 is a graph of reference voltage versus output current according to an embodiment of the present invention.

FIG. 5 is a graph of reference voltage versus system voltage according to an embodiment of the present invention.

FIG. 6 is a simulation diagram of a family of curves of reference voltage versus temperature according to an embodiment of the present invention.

FIG. 7 is a simulation diagram of a curve family of reference voltage offset versus temperature according to an embodiment of the present invention.

FIG. 8 is a simulation diagram of a curve family of a reference voltage versus an output current according to an embodiment of the present invention.

FIG. 9 is a simulation diagram of a curve family of a reference voltage versus a system voltage according to an embodiment of the present invention.

FIG. 10 is a graph of reference voltage versus temperature according to another embodiment of the present invention.

FIG. 11 is a graph of reference voltage versus output current according to another embodiment of the present invention.

FIG. 12 is a graph of reference voltage versus system voltage according to another embodiment of the present invention.

FIG. 13 is a simulation diagram of a family of curves of reference voltage versus temperature according to an embodiment of the present invention.

FIG. 14 is a simulation diagram of a curve family of reference voltage offset versus temperature according to an embodiment of the present invention.

FIG. 15 is a simulation diagram of a curve family of a reference voltage versus an output current according to an embodiment of the present invention.

FIG. 16 is a simulation diagram of a family of curves of a reference voltage versus a system voltage according to an embodiment of the present invention.

FIG. 17 is a specific circuit diagram of a bandgap reference voltage generation circuit according to yet another embodiment of the present invention.

FIG. 18 is a simulated graph of reference voltage versus temperature according to yet another embodiment of the present invention.

FIG. 19 is a simulated graph of reference voltage offset versus temperature according to yet another embodiment of the present invention.

FIG. 20 is a simulated graph of reference voltage versus output current according to yet another embodiment of the present invention.

FIG. 21 is a simulated graph of reference voltage versus system voltage according to yet another embodiment of the present invention.

FIG. 22 is another simulated graph of reference voltage versus system voltage according to yet another embodiment of the present invention.

23 is a schematic diagram of an electronic system according to an embodiment of the present invention.

Wherein, the reference signs are explained as follows:

100, 200, 1700: bandgap reference voltage generation circuit;

110: four-terminal current source circuit;

120: voltage stabilizing circuit;

130: temperature compensation circuit;

2300: electronic system;

2310: bandgap reference voltage generating circuit;

2320: load;

c1, c2, c3, c4: curves;

GND: ground voltage;

M1: the first transistor;

M2: second transistor;

M3: the third transistor;

M4: the fourth transistor;

M5: fifth transistor;

M6: the sixth transistor;

Q1: first bipolar transistor;

Q2: second bipolar transistor;

Q3: third bipolar transistor;

R1: the first resistor;

R2: second resistor;

R3: the third resistor;

R4: the fourth resistor;

R5: fifth resistor;

R6: the sixth resistor;

R7: the seventh resistor;

RL: load resistance;

I1: first current;

I2: second current;

I3: the third current;

IL: output current;

V1: first voltage;

V2: second voltage;

△VBE: base-emitter differential pressure;

VBE1: first base-emitter voltage;

VBE2: second base-emitter voltage;

VBE3: the third base-emitter voltage;

VDD: first system voltage;

VREF: Reference voltage.

Detailed ways

Various exemplary embodiments will be described more fully hereinafter with reference to the accompanying drawings, in which some exemplary embodiments are shown. However, inventive concepts may be embodied in many different forms and should not be construed as limited to the illustrative embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like numbers indicate like elements throughout.

It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used to distinguish one element from another. Thus, a first element discussed below could be termed a second element without departing from the teachings of the inventive concepts. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[Example of Bandgap Reference Voltage Generating Circuit]

Please refer to FIG. 1 . FIG. 1 is a schematic block diagram of a bandgap reference voltage generating circuit according to an embodiment of the present invention. In this embodiment, the bandgap reference voltage generation circuit 100 is used to provide a reference voltage VREF to a next stage circuit or load. The bandgap reference voltage generating circuit 100 includes a four-terminal current source circuit 110 , a voltage stabilizing circuit 120 and a temperature compensation circuit 130 . The four-terminal current source circuit 110 is electrically connected to the first system voltage VDD. The voltage stabilizing circuit 120 is electrically connected to the four-terminal current source circuit 110 and the first system voltage VDD. The temperature compensation circuit 130 is electrically connected to the four-terminal current source circuit 110 and the voltage stabilizing circuit 120 . It should be noted that the first system voltage VDD in this embodiment is the battery voltage, but it is not limited thereto. Furthermore, under the existing technology, taking the third generation (3G)/fourth generation (4G) mobile phone system as an example, the accuracy of the third generation (3G)/fourth generation (4G) mobile phone system for the RF output power There are extremely strict requirements. Because the voltage value of the mobile phone battery will vary greatly, which may vary from 3.2 volts to 4.2 volts, which will affect the accuracy of the output power of the RF power amplifier.

Through the energy bandgap reference voltage generating circuit 100 of the present disclosure, when the first system voltage VDD (that is, the battery voltage) is greater than the threshold voltage value, the four-terminal current source circuit 110 will output a stable and independent first system voltage VDD The changed first current I1 is sent to the temperature compensation circuit 130 , and the first voltage V1 and the second voltage V2 independent of the change of the first system voltage VDD are output to the voltage stabilizing circuit 120 . Then, also in the case that the first system voltage VDD is greater than the threshold voltage value, the voltage stabilizing circuit 120 receives the first voltage V1 and the second voltage V2 and passes the stable voltage difference between the first voltage V1 and the second voltage V2 to output the reference voltage VREF independent of the variation of the first system voltage VDD. Further, the stable first voltage V1 and the second voltage V2 output by the four-terminal current source circuit 110 are used to drive the voltage stabilizing circuit 120, and the first voltage V1 and the second voltage V2 can be further controlled by the stabilizing circuit. 120 locked. From another point of view, when the first system voltage VDD is greater than the threshold voltage value, due to the stable first current I1 generated by the four-terminal current source circuit 110 of the present disclosure, the first voltage V1 and the second The voltage difference between the two voltages V2 is stable. It is worth mentioning that the threshold voltage value refers to a voltage value between 2.5 volts and 3.2 volts, and its actual value is designed by the designer according to circuit design or actual application requirements.

For example, in an exemplary embodiment, the threshold voltage value is 1.8 volts, which means that the four-terminal current source circuit 110 can output a stable first current I1 when the first system voltage VDD is between 1.8 volts and 4.2 volts, The stable first current I1 will further stabilize the voltage difference between the first voltage V1 and the second voltage V2, and then enable the voltage stabilizing circuit 120 driven by the first voltage V1 and the second voltage V2 to operate at the first The system voltage VDD outputs a stable reference voltage VREF (for example, 1.5V) between 1.8V and 4.2V.

In terms of the temperature compensation effect, the stable first current I1 is used as a current source to drive or bias the temperature compensation circuit 130 to compensate the temperature curve of the reference voltage VREF output by the voltage stabilizing circuit 120, that is, the temperature of the reference voltage VREF The coefficient is equal to or close to zero temperature coefficient. Further, in this embodiment, the temperature compensation circuit 130 can compensate the temperature curve of the reference voltage VREF from a second-order temperature curve to a third-order temperature curve, so that the bandgap reference voltage generation circuit 100 of the present disclosure has a good performance. temperature compensation effect.

In order to describe the operation process of the bandgap reference voltage generating circuit 100 of the present invention in more detail, at least one of the multiple embodiments will be given below for further description.

In the following multiple embodiments, the parts different from the above-mentioned embodiment of FIG. 1 will be described, and the remaining omitted parts are the same as those of the above-mentioned embodiment of FIG. 1 . In addition, like reference numerals or numerals designate like elements for convenience of description.

[Another embodiment of the bandgap reference voltage generation circuit]

Please refer to FIG. 2 . FIG. 2 is a specific circuit diagram of a bandgap reference voltage generating circuit according to an embodiment of the present invention. Different from the above embodiment in FIG. 1 , the four-terminal current source circuit 110 includes a first transistor M1 , a second transistor M2 and a first resistor R1 . The voltage stabilizing circuit 120 includes a third transistor M3 and a fourth transistor M4. The temperature compensation circuit 130 includes a first bipolar transistor Q1, a second bipolar transistor Q2, a third bipolar transistor Q3, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5 and a sixth resistor R6 , wherein the emitter area of the second bipolar transistor Q2 is larger than the emitter area of the first bipolar transistor Q1. The drain of the first transistor M1 is connected to the first system voltage VDD. The drain of the second transistor M2 is connected to the source of the first transistor M1, and the source of the second transistor M2 is connected to the gate of the first transistor M1, wherein the first transistor M1 and the second transistor M2 are depletion transistors. One end of the first resistor R1 is connected to the source of the second transistor M2, and the other end of the first resistor R1 is connected to the gate of the second transistor M2. The drain of the third transistor M3 is connected to the first system voltage VDD, and the gate of the third transistor M3 is connected to the gate of the first transistor M1 to receive the first voltage V1. The drain of the fourth transistor M4 is connected to the source of the third transistor M3, the gate of the fourth transistor M4 is connected to the other end of the first resistor R1 to receive the second voltage V2, the source of the fourth transistor M4 is connected to the load resistor RL and The reference voltage VREF is output, wherein the third transistor M3 and the fourth transistor M4 are depletion transistors. The emitter of the first bipolar transistor Q1 is connected to the ground voltage GND. One end of the second resistor R2 is connected to the base of the first bipolar transistor Q1. One end of the third resistor R3 is connected to the other end of the second resistor R2, and the other end of the third resistor R3 is connected to the collector of the first bipolar transistor Q1. One end of the fourth resistor R4 is connected to one end of the third resistor R3. One end of the fifth resistor R5 is connected to the other end of the fourth resistor R4 and connected to the fourth transistor M4. The base of the second bipolar transistor Q2 is connected to the other end of the third resistor R3, and the collector of the second bipolar transistor Q2 is connected to the other end of the fifth resistor R5. One end of the sixth resistor R6 is connected to the emitter of the second bipolar transistor Q2, and the other end of the sixth resistor R6 is connected to the ground voltage GND.

Before proceeding to the following description, it must be explained that the positive temperature coefficient described in this disclosure indicates that its physical quantity (such as voltage value, current value or resistance value) is directly proportional to temperature, that is, when the temperature As the temperature rises or falls, its physical quantity will rise or fall with temperature; the negative temperature coefficient described in this disclosure indicates that its physical quantity has an inverse relationship with temperature, that is, its physical quantity will increase or decrease when the temperature rises or falls. Decrease or increase with temperature. The zero temperature coefficient described in this disclosure indicates that its physical quantity (such as voltage value, current value or resistance value) has an independent relationship with temperature, that is, when the temperature rises or falls, its physical quantity does not change with each other. rise or fall with temperature.

What is to be taught next is to further explain the working principle of the bandgap reference voltage generating circuit 200 so as to better understand the present disclosure.

When the energy bandgap reference voltage generation circuit 200 faces changes in the first system voltage VDD (that is, the battery voltage), the present disclosure provides a stable first voltage through the first transistor M1, the second transistor M2 and the first resistor R1. current I1. Further, when the first system voltage VDD is greater than the threshold voltage value (such as 1.8 volts), the gate and source of the first transistor M1 will be maintained at a stable voltage value, and the gate and source of the second transistor M2 will be maintained at a stable voltage. The sources are also maintained at a stable voltage value, and then the first current I1 is generated through the first resistor R1. Since one end of the first resistor R1 is electrically connected to the source of the second transistor M2, and the other end of the first resistor R1 is electrically connected to the gate of the second transistor M2, the voltage difference between the two ends of the first resistor R1 will maintain At a stable voltage value, the first current I1 is stabilized. In this embodiment, the designer can adjust the resistance value of the first resistor R1 to obtain the required magnitude of the first current I1 to meet actual application requirements. Next, in this embodiment, the gate voltage of the first transistor M1 is used as the first voltage V1, and the gate voltage of the second transistor M2 is used as the second voltage V2, and the first voltage V1 and the second The voltage V2 is used to drive or bias the voltage regulator circuit 120 . Further, because the gate of the third transistor M3 receives the first voltage V1 and the third transistor M3 is a depletion transistor, the source voltage of the third transistor Q3 is locked at a stable voltage value by the stable first voltage V1 , so that the reference voltage VREF is locked at the first reference voltage value independent of the change of the first system voltage VDD, wherein the first reference voltage value is equal to the sum of the voltage drop of the fifth resistor R5 and the third base-emitter voltage VBE3. For example, in the present embodiment, the source-gate voltage of the third transistor M3 is 1 volt, so the source voltage of the third transistor M3 will be greater than the first voltage V1 by about 1 volt, so that the source of the third transistor M3 The voltage is locked at the sum of the first voltage V1 and 1 volt, wherein the drain voltage of the fourth transistor M4 is equal to the source voltage of the third transistor M3. Next, since both the gate voltage and the drain voltage of the fourth transistor M4 are locked, the source voltage of the fourth transistor M4 (that is, the reference voltage VREF) is also locked at a fixed voltage value. From another point of view, the voltage stabilizing circuit 120 is constructed by using cascaded depletion transistors, so as to provide a stable reference voltage VREF independent of battery voltage variations. In this embodiment, the first to fourth transistors M1 - M4 are pseudomorphic high-speed electron mobility transistors (Pseudomorphic High Electron Mobility Transistor, PHEMT).

In terms of the temperature compensation effect, in this embodiment, the temperature compensation circuit 130 utilizes the first bipolar transistor Q1, the second bipolar transistor Q2, the third bipolar transistor Q3, the second resistor R2, the third resistor R3, the fourth The resistor R4, the fifth resistor R5 and the sixth resistor R6 are constructed, wherein the bipolar transistors Q1, Q2 and Q3 are heterojunction bipolar transistors (Heterojunction Bipolar Transistor, HBT) and have base-emitter electrodes with negative temperature coefficients respectively Voltages VBE1, VBE2, and VBE3. As shown in FIG. 2, the voltage difference across the sixth resistor R6 is the base-emitter voltage between the first base-emitter voltage VBE1 of the first bipolar transistor Q1 and the second base-emitter voltage VBE2 of the second bipolar transistor VBE2. Voltage difference △VBE (as shown in formula (1)), where it should be noted that the effects of the second resistor R2 and the third resistor R3 are assumed to be ignored in order to obtain this formula, and the base-emitter voltage difference △VBE voltage with a negative temperature coefficient. Next, the second current I2 flowing through the sixth resistor R6 is a current with a positive temperature coefficient through the sixth resistor R6 and the base-emitter voltage difference ΔVBE. Then, if the base current effect of the second transistor Q2 and the third transistor Q3 is ignored, the third current I3 flowing through the fifth resistor R5 is equal to the second current I2, and the third current I3 also has a positive temperature coefficient characteristic. It can be known from Kirchhoff's voltage law (KVL) that the reference voltage VREF is the sum of the voltage drop of the fifth resistor R5 and the base-emitter voltage VBE3 of the third transistor Q3, as shown in formula (2), in In one embodiment, the reference voltage is 1.48 volts. Therefore, the designer can adjust the resistance values of the fifth resistor R5 and the sixth resistor R6 so that the reference voltage VREF can exhibit a characteristic that is equal to or close to zero temperature coefficient when the ambient temperature changes. It is worth mentioning that the present disclosure can compensate the second-order temperature curve of the reference voltage VREF into a third-order temperature curve by adjusting the resistance values of the second resistor R2 and the third resistor R3 .

△VBE=VBE1–VBE2 formula (1)

VREF=I3×R5+VBE3

=(R5/R6)×△VBE+VBE3 formula (2)

Based on the above, the energy bandgap reference voltage generation circuit 200 of the present disclosure faces changes in battery voltage (such as the voltage value of a mobile phone battery) and changes in ambient temperature (such as minus 55 degrees Celsius to 125 degrees Celsius) It can provide a stable reference voltage VREF independent of the two variables of battery voltage and ambient temperature.

Please refer to FIG. 2 and FIG. 3 at the same time. FIG. 3 is a graph showing the temperature compensation effect of the bandgap reference voltage generating circuit according to an embodiment of the present invention. In Fig. 3, the horizontal axis is the temperature (unit is Celsius), the left vertical axis is the reference voltage (unit is volts), the right horizontal axis is the offset of the reference voltage (the unit is %), and the curve c1 represents the reference voltage, Curve c2 represents the offset of the reference voltage. It can be seen from Fig. 3 that both curves c1 and c2 are third-order temperature curves (adjusted by the first resistor R1, the second resistor R2 and the third resistor R3), and between minus 55 degrees Celsius and 125 degrees Celsius, the reference voltage The voltage value of VREF can be stably maintained at 1.481 volts, and the offset of the reference voltage VREF is also very small (less than plus or minus 0.003%). Please refer to FIG. 2 and FIG. 4 at the same time. FIG. 4 is a graph of reference voltage versus output current according to an embodiment of the present invention. In FIG. 4 , the horizontal axis is the output current IL (in milliamps), and the vertical axis is the reference voltage (in volts), where the output resistance is less than 0.2 ohms. It can be seen from Figure 4 that under different load resistances RL corresponding to different output currents IL, the reference voltage VREF can still be maintained at a stable voltage value (about 1.48 volts), so the load regulation (Load Regulation) is about 0.02% . Please refer to FIG. 2 and FIG. 5 at the same time. FIG. 5 is a graph of reference voltage versus system voltage according to an embodiment of the present invention. In Figure 5, the horizontal axis is the system voltage (in volts), and the vertical axis is the reference voltage (in volts), and it can be seen from Figure 5 that when the system voltage VDD is between 3 volts and 4.2 volts, the reference voltage VREF can still be Maintain a fixed voltage value, such as 1.48 volts. Therefore, the power supply rejection ratio (Power Supply Rejection Ratio, PSRR) of the bandgap reference voltage generating circuit 200 in this disclosure is about 96 dB, and the line regulation (Line Regulation) is about 0.002%. Accordingly, it can be seen from FIG. 3 to FIG. 5 that the reference voltage VREF can pass through the variation of the ambient temperature, the variation of the load resistance RL (corresponding to the variation of the output current IL) and the variation of the first system voltage VDD. To reveal the working mechanism of the content, it is maintained at a fixed voltage value, such as 1.48 volts. Next, the simulation curve family of this embodiment is provided to better understand the efficacy of this embodiment. Please refer to FIG. 6 to FIG. 9 at the same time. FIG. It is a simulated graph of reference voltage VREF versus ambient temperature obtained when the first system voltage is swept from 3 volts (volt, V) to 5 volts. FIG. 7 is a simulation diagram of a curve family of reference voltage offset versus temperature according to an embodiment of the present invention. It can be seen from FIG. 6 and FIG. 7 that, in this embodiment, the reference voltage VREF generated by the bandgap reference voltage generating circuit 200 can be stably compared with the change of the ambient temperature and the change of the system voltage VDD (battery voltage). It is maintained at 1.48 volts, and its difference is only plus or minus 0.0085%, which has a very good anti-change effect. 8 is a simulation graph of a reference voltage versus output current curve family according to an embodiment of the present invention, which is a simulation graph of the reference voltage versus output current obtained when the first system voltage VDD sweeps from 3 volts to 5 volts. FIG. 9 is a simulation diagram of a curve family of reference voltage versus system voltage according to an embodiment of the present invention. In FIG. 9 , the simulation diagram is obtained by setting the simulated ambient temperature to scan between minus 55 degrees Celsius and 125 degrees Celsius. From the point of view of the curve family, the reference voltage VREF generated by the bandgap reference voltage generation circuit 200 is in the face of the change of the ambient temperature, the change of the load resistance RL (corresponding to the change of the output current IL) and the first system voltage VDD When the voltage changes, it can be maintained at a stable voltage value, such as 1.48 volts, through the working mechanism of the present disclosure.

In another embodiment, the simulation temperature is set between zero degrees Celsius and 80 degrees Celsius to scan the bandgap reference voltage generation circuit 200, and the reference voltage VREF provided by the bandgap reference voltage generation circuit 200 is compared with the temperature change will be more stable. Please refer to FIG. 10 , which is a graph of reference voltage versus temperature according to another embodiment of the present invention. In FIG. 10 , the horizontal axis is the temperature (unit is Celsius), the left vertical axis is the reference voltage (unit is volts) and the right vertical axis is the offset of the reference voltage (unit is %). In FIG. 10, curve c3 represents reference voltage VREF and curve c4 represents the offset of reference voltage VREF. The difference is only 2.8 microvolts (micro volt), and the offset of the reference voltage VREF is less than plus or minus 0.0001%, which has an excellent temperature compensation effect. Next, please refer to FIG. 11 and FIG. 12, FIG. 11 is a graph of reference voltage versus output current according to another embodiment of the present invention, and FIG. 12 is a graph of reference voltage versus system voltage according to another embodiment of the present invention . It can be seen from FIG. 11 and FIG. 12 that when the reference voltage VREF changes with respect to the output current IL and the system voltage VDD, the reference voltage VREF can maintain a stable voltage value of 1.456 volts, wherein the power supply of the bandgap reference voltage generating circuit 200 Rejection ratio (PSRR) can be improved to 100dB (can be learned from Figure 12). From another point of view, please refer to FIGS. 13 to 16 . FIG. 13 is a simulation diagram of a curve family of reference voltage versus temperature according to an embodiment of the present invention. FIG. 14 is a simulation diagram of a curve family of reference voltage offset versus temperature according to an embodiment of the present invention. FIG. 15 is a simulation diagram of a curve family of a reference voltage versus an output current according to an embodiment of the present invention. FIG. 16 is a simulation diagram of a family of curves of a reference voltage versus a system voltage according to an embodiment of the present invention. It can be seen from Figure 15 to Figure 16 that the reference voltage VREF can provide a stable voltage value, such as 1.456 volts, in the face of changes in ambient temperature, changes in output current IL and changes in system voltage VDD, so it has excellent stability .

In at least one of the following embodiments, parts different from the above-mentioned embodiment in FIG. 2 will be described, and other omitted parts are the same as those in the above-mentioned embodiment in FIG. 2 . In addition, like reference numerals or numerals designate like elements for convenience of description.

[Another embodiment of the bandgap reference voltage generation circuit]

Please refer to FIG. 17 . FIG. 17 is a specific circuit diagram of a bandgap reference voltage generating circuit according to yet another embodiment of the present invention. Different from the above-mentioned embodiment in FIG. 2 , in the bandgap reference voltage generating circuit 1700 of this embodiment, the voltage stabilizing circuit 120 includes a fifth transistor M5 and a sixth transistor M6 . The drain of the fifth transistor M5 is connected to the first system voltage VDD, the gate of the fifth transistor M5 is connected to the source of the first transistor M1 to receive the first voltage V1, and the stable first voltage V1 makes the source of the fifth transistor Q5 The pole voltage is locked at a stable voltage value, so that the reference voltage VREF is locked at the first reference voltage value independent of the change of the first system voltage VDD, wherein the first reference voltage value is equal to the voltage drop of the fifth resistor R5 and the first The sum of the three base-emitter voltages VBE3. The drain of the sixth transistor M6 is connected to the source of the fifth transistor M5, the gate of the sixth transistor M6 is connected to the gate of the first transistor M1 to receive the second voltage V2, and the source of the sixth transistor M6 is connected to the load resistor RL and One end of the fifth resistor R5 outputs the reference voltage VREF, wherein the fifth transistor M5 and the sixth transistor M6 are depletion transistors.

In this embodiment, when the first system voltage VDD is greater than the threshold voltage value (such as 3 volts), the gate and source of the first transistor M1 will be maintained at a stable voltage value, and the gate of the second transistor M2 The pole and the source are respectively maintained at stable voltage values, and then the first current I1 is generated through the first resistor R1. Furthermore, the gate of the fifth transistor M5 is connected to the source voltage of the first transistor M1 as the first voltage V1, and the gate of the sixth transistor M6 is connected to the source voltage of the second transistor M2 as the second voltage V2. The bandgap reference voltage generating circuit 1700 uses the first voltage V1 (the source voltage of the first transistor M1 ) and the second voltage V2 (the source voltage of the first transistor M2 ) to drive or bias the voltage stabilizing circuit 120 . Further, since the gate of the fifth transistor M5 receives the stable source voltage of the first transistor M1 as the first voltage V1 and the fifth transistor M5 itself is a depletion transistor, the source voltage of the fifth transistor M5 will be is greater than the first voltage by about 1 volt, so that the source voltage of the fifth transistor M5 is locked at the voltage value of the sum of the first voltage V1 and 1 volt, wherein the drain voltage of the sixth transistor M6 is equal to the voltage of the fifth transistor M5 the source voltage. Then, since both the gate voltage and the drain voltage of the sixth transistor M6 are locked, the source voltage of the sixth transistor M6 (that is, the reference voltage VREF) is also locked at a fixed voltage value.

In terms of temperature compensation effect, different from the above embodiment in FIG. 2 , the temperature compensation circuit in the embodiment in FIG. 17 further includes a seventh resistor R7. One end of the seventh resistor R7 is connected to the base of the third bipolar transistor Q3, and the other end of the seventh resistor R7 is connected to the ground voltage GND. In this embodiment, the seventh resistor is used to increase the first reference voltage value (such as 1.48 volts) of the reference voltage VREF to a second reference voltage value (such as 2.78 volts), wherein the second reference voltage value of the reference voltage VREF is equal to The sum of the voltage drop of the fifth resistor R5 and the voltage drop of the seventh resistor R7. The rest are the same as the above-mentioned embodiment in FIG. 2 , and will not be repeated here.

Please refer to FIG. 17 , FIG. 18 , and FIG. 19 at the same time. FIG. 18 is a simulation graph of reference voltage versus temperature according to another embodiment of the present invention. FIG. 19 is a simulated graph of reference voltage offset versus temperature according to yet another embodiment of the present invention. When the temperature changes between minus 55 degrees Celsius and 125 degrees Celsius, the temperature curve of the reference voltage VREF can present an excellent third-order temperature curve, and the offset of the reference voltage is less than plus or minus 0.0067%. Please refer to FIG. 20 and FIG. 21 , FIG. 20 is a simulated graph of reference voltage versus output current according to yet another embodiment of the present invention. FIG. 21 is a simulated graph of reference voltage versus system voltage according to yet another embodiment of the present invention. It can be seen from FIG. 20 and FIG. 21 that the reference voltage VREF provided by the bandgap reference voltage generation circuit 1700 can also maintain a stable second reference voltage value in the face of changes in the output current IL and system voltage VDD. Such as 2.78 volts. Please refer to FIG. 22 . FIG. 22 is another simulated graph of the reference voltage versus the system voltage according to yet another embodiment of the present invention. It can be seen from FIG. 22 that when the system voltage VDD sweeps from 2.5 volts to 3.5 volts, the reference voltage VREF starts to enter a stable first reference voltage value (2.78 volts) and maintains at around 2.85 volts.

[An embodiment of the electronic system]

Please refer to FIG. 23 , which is a schematic diagram of an electronic system according to an embodiment of the present invention. The electronic system 2300 includes a bandgap reference voltage generation circuit 2310 and a load 2320 connected to the bandgap reference voltage generation circuit 2310 . The bandgap reference voltage generation circuit 2310 can be one of the bandgap reference voltage generation circuits 200 and 1700 in the above-mentioned embodiments, and is used to provide a reference voltage VREF to the load 2320 or the next stage circuit. The electronic system 2300 may be a system in various types of electronic devices, such as handheld devices or mobile devices.

[Possible efficacy of the embodiment]

In summary, the energy bandgap reference voltage generation circuit proposed by the embodiments of the present invention is different from the environment temperature change (such as negative 50 degrees Celsius to 120 degrees Celsius) when facing changes in battery voltage (such as the voltage value of a mobile phone battery). It can provide a stable reference voltage independent of the two variables of battery voltage and ambient temperature.

In at least one of the multiple embodiments of the present disclosure, the bandgap reference voltage generation circuit can provide a stable reference voltage in the face of changes in load resistance (corresponding to different output currents).

The above descriptions are only examples of the present invention, and are not intended to limit the scope of the patent claims of the present invention.

Claims (10)

1. A bandgap reference voltage generation circuit for providing a reference voltage, characterized in that the bandgap reference voltage generation circuit comprises: A four-terminal current source circuit is electrically connected to a first system voltage. When the first system voltage is greater than a threshold voltage, a first voltage, a second voltage and a first voltage output by the four-terminal current source circuit a current independent of changes in the first system voltage; A voltage stabilizing circuit, electrically connected to the four-terminal current source circuit, the voltage stabilizing circuit receives the first voltage and the second voltage and when the first system voltage is greater than the threshold voltage value, passes the first and the a stable voltage difference between the second voltages, the voltage stabilizing circuit outputs the reference voltage independent of the variation of the first system voltage; and A temperature compensation circuit is electrically connected to the four-terminal current source circuit and the voltage stabilizing circuit. The temperature compensation circuit receives the first current and is used for compensating the temperature curve of the reference voltage output by the voltage stabilizing circuit. 2. The bandgap reference voltage generating circuit as claimed in claim 1, wherein the temperature curve of the reference voltage output by the voltage stabilizing circuit is compensated, so that the second-order temperature curve of the reference voltage is compensated as a third-order temperature curve. 3. The bandgap reference voltage generation circuit as claimed in claim 1, wherein when the first system voltage is greater than the threshold voltage value, the four-terminal current source circuit outputs the stable first voltage and the second voltage, And outputting the stable first current. 4. The bandgap reference voltage generating circuit as claimed in claim 1, wherein the four-terminal current source circuit comprises: a first transistor, the drain of which is connected to the first system voltage; a second transistor, the drain of which is connected to the source of the first transistor, and the source of which is connected to the gate of the first transistor, wherein the first and the second transistors are depletion transistors; and A first resistor, one end of which is connected to the source of the second transistor, and the other end is connected to the gate of the second transistor, wherein when the first system voltage is greater than the threshold voltage value, the first transistor, the second transistor The first current generated by the two transistors and the first resistor is a stable current independent of the change of the first system voltage. 5. The bandgap reference voltage generation circuit as claimed in claim 4, the voltage stabilizing circuit comprising: a third transistor, the drain of which is connected to the first system voltage, and the gate of which is connected to the gate of the first transistor to receive the first voltage; and A fourth transistor, its drain is connected to the source of the third transistor, its gate is connected to the other end of the first resistor to receive the second voltage, its source is connected to a load resistor and outputs the reference voltage, wherein the The third and the fourth transistors are depletion transistors, The source voltage of the third transistor is locked at a stable voltage value through the stable first voltage, so that the reference voltage is locked at a first reference voltage value independent of the change of the first system voltage. 6. The bandgap reference voltage generation circuit as claimed in claim 4, the voltage stabilizing circuit comprising: a fifth transistor, the drain of which is connected to the first system voltage, and the gate of which is connected to the source of the first transistor to receive the first voltage; and A sixth transistor, the drain of which is connected to the source of the fifth transistor, the gate of which is connected to the gate of the first transistor to receive the second voltage, the source of which is connected to a load resistor and outputs the reference voltage, wherein the The fifth and sixth transistors are depletion-type transistors, wherein the source voltage of the fifth transistor is locked at a stable voltage value through the stable first voltage, so that the reference voltage is independent of the first system voltage changes and is locked at a first reference voltage value. 7. The bandgap reference voltage generating circuit as claimed in claim 5 or 6, the temperature compensation circuit comprising: a first bipolar transistor, the emitter of which is connected to a ground voltage; a second resistor, one end of which is connected to the base of the first bipolar transistor; A third resistor, one end of which is connected to the other end of the second resistor, and the other end of which is connected to the collector of the first bipolar transistor; A fourth resistor, one end of which is connected to one end of the third resistor; a fifth resistor, one end of which is connected to the other end of the fourth resistor and connected to the source of the fourth transistor or the sixth transistor; A second bipolar transistor, the base of which is connected to the other end of the third resistor, and the collector of which is connected to the other end of the fifth resistor; A sixth resistor, one end of which is connected to the emitter of the second bipolar transistor, and the other end of which is connected to the ground voltage, wherein a first base-emitter voltage of the first bipolar transistor and a voltage of the second bipolar transistor a base-emitter voltage difference between a second base-emitter voltage to make a second current flowing through the sixth resistor a positive temperature coefficient current; and A third bipolar transistor, its base is connected to the collector of the second bipolar transistor, its emitter is connected to the ground voltage, and its collector is connected to the other end of the first resistor, the third bipolar transistor has a negative temperature coefficient of a third base-emitter voltage, By adjusting the resistance values of the fifth resistor and the sixth resistor, the reference voltage is equal to or close to zero temperature coefficient voltage, and the first reference voltage value is equal to the voltage drop of the fifth resistor and the third base emitter sum of pole voltages. 8. The bandgap reference voltage generation circuit as claimed in claim 7, wherein the second-order temperature curve of the reference voltage is compensated to a third-order temperature curve by adjusting the resistance values of the second and third resistors. 9. The bandgap reference voltage generating circuit as claimed in claim 7, the temperature compensation circuit further comprising: A seventh resistor, one end of which is connected to the base of the third bipolar transistor, and the other end of which is connected to the ground voltage, the seventh resistor is used to raise the first reference voltage value of the reference voltage to a second reference voltage value, wherein the second reference voltage value of the reference voltage is equal to the sum of the voltage drop of the fifth resistor and the voltage drop of the seventh resistor. 10. An electronic system, characterized in that the electronic system comprises: A bandgap reference voltage generation circuit electrically connected to a first reference voltage, the bandgap reference voltage generation circuit includes: A four-terminal current source circuit electrically connected to the first system voltage and when the first system voltage is greater than a threshold voltage value, a first voltage, a second voltage and a first voltage output by the four-terminal current source circuit current is independent of changes in the first system voltage; A voltage stabilizing circuit, electrically connected to the four-terminal current source circuit, the voltage stabilizing circuit receives the first voltage and the second voltage and when the first system voltage is greater than the threshold voltage value, through the first and the a stable voltage difference between the second voltages, the voltage stabilizing circuit outputs a reference voltage independent of variations in the first system voltage; and a temperature compensation circuit electrically connected to the four-terminal current source circuit and the voltage stabilizing circuit, the temperature compensation circuit receives the first current and is used to compensate the temperature curve of the reference voltage output by the voltage stabilizing circuit; and A load is electrically connected to the bandgap reference voltage generation circuit to receive the reference voltage.