WO2022087812A1

WO2022087812A1 - Bandgap voltage reference circuit and integrated circuit

Info

Publication number: WO2022087812A1
Application number: PCT/CN2020/123917
Authority: WO
Inventors: 陈建兴
Original assignee: 深圳市汇顶科技股份有限公司
Priority date: 2020-10-27
Filing date: 2020-10-27
Publication date: 2022-05-05
Also published as: CN114080580A; CN114080580B

Abstract

A bandgap voltage reference circuit and an integrated circuit. The bandgap voltage reference circuit comprises: a reference voltage circuit (10) and a feedback branch (20), wherein the feedback branch (20) is connected to the reference voltage circuit (10); the reference voltage circuit (10) comprises a first switch tube group (Z1) and a second switch tube group (Z2), the first switch tube group (Z1) and the second switch tube group (Z2) being mirrored switch tube groups; the reference voltage circuit (10) is used for providing voltage with a zero temperature coefficient; the first switch tube group (Z1) and the second switch tube group (Z2) are used for providing a constant current; and the feedback branch (20) clamps the voltages of the first switch tube group (Z1) and the second switch tube group (Z2) by means of introducing a feedback signal into the reference voltage circuit (10), so as to offset a channel length modulation effect of switch tubes in the first switch tube group (Z1) and the second switch tube group (Z2), without increasing a circuit operating voltage.

Description

Bandgap reference circuit and integrated circuit

technical field

The present invention relates to the technical field of microelectronics, and in particular, to a bandgap reference circuit and an integrated circuit having the bandgap reference circuit.

Background technique

The Bandgap Voltage Reference (English: Bandgap Voltage Reference) circuit is used to provide a temperature-independent reference voltage, usually obtained by superimposing a voltage with a positive temperature coefficient and a voltage with a negative temperature coefficient.

As shown in Figure 1, a common op amp-free bandgap reference circuit includes a branch that produces a positive temperature coefficient current and a branch that produces a negative temperature coefficient voltage. Among them, the mirror transistors M1 to M4, the transistors Q1 and Q2, and the resistor R11 form a branch for providing a current with a positive temperature coefficient, and the resistor R12 and transistor Q3 form a branch for providing a voltage with a negative temperature coefficient. However, in the circuit shown in Figure 1, the channel length modulation effects of the mirror transistors M1 to M4 are different, resulting in different currents of the mirror transistors M1 and M2, so that the source voltages of the mirror transistors M3 and M4 are also different, making the output There is a deviation in the reference voltage. As shown in FIG. 2 , mirror transistors M5 to M8 are usually added to the branch of the voltage with positive temperature coefficient. The mirror transistors M5 and M6 are used to clamp the voltage of the mirror transistors M1 and M2 to ensure the drain of the mirror transistors M1 and M2 The voltages are the same, which cancels the channel length modulation effect of the mirror transistors M1 and M2. The mirror transistors M7 and M8 are used to clamp the voltages of the mirror transistors M3 and M4, to ensure that the source voltages of the mirror transistors M3 and M4 are the same, and to cancel the channel length modulation effect of the mirror transistors M3 and M4.

However, in the circuit structure shown in FIG. 2, a higher power supply voltage is required for the circuit to work properly.

SUMMARY OF THE INVENTION

The present application provides a bandgap reference circuit and an integrated circuit, which aim to cancel the channel length modulation effect of the mirror transistor, and the required power supply voltage amplitude is the same as that of the bandgap reference circuit shown in FIG. 1, and there is no need to increase the power supply voltage amplitude .

In a first aspect, the present application provides a bandgap reference circuit, characterized by comprising: a reference voltage circuit and a feedback branch (20);

The feedback branch (20) is connected to the reference voltage circuit, and the reference voltage circuit includes a first switch tube group (Z1) and a second switch tube group (Z2), the first switch tube group (Z1) and the second switch tube group (Z2) ) is the mirror transistor group;

The reference voltage circuit is used to provide a voltage with zero temperature coefficient, the first switch tube group (Z1) and the second switch tube group (Z2) are used to provide a constant current, and the feedback branch (20) is used to introduce a feedback signal into the reference voltage circuit. The voltages of the first switch tube group (Z1) and the second switch tube group (Z2) are clamped.

Optionally, the first switch tube group (Z1) includes a first switch tube (T1) and a second switch tube (T2);

The second end of the first switch tube (T1) is connected to the first end of the second switch tube (T2);

The feedback circuit (20) is used to form a feedback signal according to the output signal of the first end of the second switch tube (T2), and introduce the feedback signal to the control end of the second switch tube (T2) to clamp the second switch tube (T2). T2) voltage.

Optionally, the second switch tube group (Z2) includes a third switch tube (T3) and a fourth switch tube (T4);

The second end of the third switch tube (T3) is connected to the first end of the fourth switch tube (T4);

The second end of the third switch tube (T3) is short-circuited with the control end, and the control end of the third switch tube (T3) is connected to the control end of the first switch tube (T1) to clamp the third switch tube (T3) voltage.

Optionally, the control terminal of the second switch tube (T2) is connected to the control terminal of the fourth switch tube (T4) to clamp the voltage of the fourth switch tube (T4).

Optionally, the feedback branch (20) includes: a seventh switch transistor (T7), an eighth switch transistor (T8) and a ninth switch transistor (T9);

The second end of the seventh switch tube (T7) is connected to the first end of the eighth switch tube (T8), and the second end of the eighth switch tube (T8) is connected to the first end of the ninth switch tube (T9). connect;

The control end of the seventh switch tube (T7) is connected to the first end of the second switch tube (T2), so as to form a feedback signal according to the output signal of the first end of the second switch tube (T2);

The first end of the eighth switch tube (T8) is connected to the control end of the second switch tube (T2) to introduce a feedback signal.

Optionally, the first end of the eighth switch tube (T8) is short-circuited with the control end, and the second end of the ninth switch tube (T9) is short-circuited with the control end, so that the first end of the eighth switch tube (T8) is short-circuited. The terminal voltage is the same as the first terminal voltage of the second switch tube (T2).

Optionally, the feedback branch further includes: a first resistor (R1), and the first resistor (R1) is connected in parallel with the ninth switch transistor (T9).

Optionally, the reference voltage circuit includes: a reference current circuit (101) and an output circuit (102);

The reference current circuit (101) is connected with the output circuit (102), the reference current circuit (101) is used for providing a current with zero temperature coefficient, and the output circuit (102) is used for converting the current with zero temperature coefficient into a voltage output with zero temperature coefficient .

Optionally, the reference current circuit (101) further includes: a positive temperature coefficient current branch (1011) for providing a positive temperature coefficient current;

The positive temperature coefficient current branch (1011) further includes a first current branch (1013) and a second current branch (1014) connected in parallel;

The first current branch (1013) further includes a fifth switch tube (T5), and the fifth switch tube (T5) is connected in series with the first switch tube group (Z1);

The second current branch further includes a third switch tube group (Z3) and a sixth resistor (R6), and the second switch tube group (Z2), the sixth resistor (R6) and the third switch tube group (Z3) are sequentially connected in series ;

The third switch tube group (Z3) includes a plurality of sixth switch tubes (T6) connected in parallel.

Optionally, the reference current circuit (101) includes: a negative temperature coefficient current branch (1012) for providing a current with a negative temperature coefficient;

The negative temperature coefficient current branch (1012) further includes a second resistor (R2) and a third resistor (R3);

One end of the second resistor (R2) is connected to the second end of the second switch tube (T2), the other end of the second resistor (R2) is grounded, and one end of the third resistor (R3) is connected to the fourth switch tube (T4) ) is connected, the other end of the third resistor (R3) is connected to ground, and both the second resistor (R2) and the third resistor (R3) are used to provide a current with a negative temperature coefficient.

Optionally, the output circuit includes a tenth switch tube (T10) and a fourth resistor (R4);

The first end of the tenth switch tube (T10) is connected to the power supply, the control end of the tenth switch tube (T10) is connected to the first end of the second switch tube (T2), and the first end of the tenth switch tube (T10) is connected to the power supply. The two ends are connected to one end of the fourth resistor (R4), and the other end of the fourth resistor (R4) is grounded.

Optionally, the reference current circuit includes: a negative temperature coefficient current branch for providing a current with a negative temperature coefficient;

The negative temperature coefficient current branch further includes an eleventh switch tube (T11), and the control end of the eleventh switch tube (T11) is short-circuited with the second end and grounded.

Optionally, the output circuit includes a fifth resistor (R5) and a twelfth switch tube (T12);

The first end of the twelfth switch tube (T12) is connected to the power supply, the control end of the twelfth switch tube (T12) is connected to the first end of the second switch tube (T2), and the twelfth switch tube (T12) ) is connected to one end of the fifth resistor (R5), and the other end of the fifth resistor (R5) is connected to the first end of the eleventh switch tube (T11).

In a second aspect, the present application provides an integrated circuit, including the bandgap reference circuit involved in the first aspect and the optional solution.

The present application provides a bandgap reference circuit and an integrated circuit, including: a reference voltage circuit and a feedback branch, the reference voltage circuit further includes a first switch transistor group and a second switch transistor group arranged in a mirror image, and the reference voltage circuit is used to provide Bandgap reference voltage, the feedback branch clamps the voltage of the first switch tube group and the second switch tube group by introducing a feedback signal to the reference voltage circuit, so as to cancel the voltage of the switch tubes in the first switch tube group and the second switch tube group. The channel length modulation effect ensures that the voltage of the mirror switch is the same. By introducing a feedback method to clamp the switch voltage, compared with the method of connecting the switch in series in the switch group, there is no need to increase the power supply voltage of the circuit and expand the use range of the circuit. Intersecting the bandgap reference circuit with op amp components, this scheme does not use op amp components, and the cost is lower.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present application, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic structural diagram of a bandgap reference voltage circuit provided by the prior art;

2 is a schematic structural diagram of another bandgap reference voltage circuit provided by the prior art;

FIG. 3 is a schematic structural diagram of a bandgap reference voltage circuit provided by an embodiment of the present application;

FIG. 4 is a partial structural schematic diagram of a bandgap reference voltage circuit provided by another embodiment of the present application;

5 is a schematic structural diagram of a bandgap reference voltage circuit provided by another embodiment of the present application;

6 is a schematic structural diagram of a bandgap reference voltage circuit provided by another embodiment of the present application;

FIG. 7 is a schematic structural diagram of a bandgap reference voltage circuit provided by another embodiment of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

As shown in Figure 1, a common bandgap reference circuit includes a voltage branch with a positive temperature coefficient, a voltage branch with a negative temperature coefficient, and an output branch.

The positive temperature coefficient voltage branch includes transistors M1 to M4, a plurality of transistors Q1 and one transistor Q2, and a resistor R11. The drain of the transistor M1 is connected to the drain of the transistor M3, and the drain of the transistor M2 is connected to the drain of the transistor M4. The gate of the transistor M1 is connected to the gate of the transistor M2 and then connected to the drain of the transistor M1. The gate of the transistor M3 is connected to the gate of the transistor M4 and then connected to the drain of the transistor M4. Transistor M1 and transistor M2 are mirror transistors, and transistor M3 and transistor M4 are also mirror transistors. The collectors of each transistor Q1 are connected to each other, the bases of each transistor Q1 are connected to each other, and the collector and base of each transistor Q1 are short-circuited. After the emitters of each transistor Q1 are connected to each other, it is connected to one end of the resistor R11, The other end of the resistor R11 is connected to the source of the transistor M3.

The voltage branch of the negative temperature coefficient further includes a resistor R12 and a transistor Q3, the collector and the base of the transistor Q3 are short-circuited, and the emitter of the transistor Q3 is connected to one end of the resistor R12.

The output branch includes a transistor M7, and the transistor M7 is used for outputting the bandgap reference voltage after superimposing the voltage of the positive temperature coefficient and the voltage of the negative temperature coefficient.

The operating principle of the bandgap reference circuit shown in Figure 1 is:

In the voltage branch with positive temperature coefficient, the number of transistors Q1 is N times that of Q2, so that the current flowing through the resistor R11 is:

Among them, T is the absolute temperature, k is the Boltzmann constant, q is the amount of electron charge, and both k and q are positive values, ΔVbe is the voltage Vbe between the base and emitter of the transistors Q1 and Q-transistor 2 difference, ΔVbe is the voltage with a positive temperature coefficient, and R11 represents the resistance value of the resistor.

In the voltage branch with negative temperature coefficient, the voltage Vbe between the base electrode and the emitter electrode of the transistor Q3 is a voltage with a negative temperature coefficient.

The transistor M9 mirrors the currents of the transistors M1 and M2, that is, the current flowing in the transistor M9 is the same as the current flowing in the transistor M1, and through the resistor R12 and the switch Q3, the output voltage Vbg is obtained as:

Among them, Vbe is a voltage with a negative temperature coefficient, and by adjusting the ratio of R12 and R11, Vbg can be made a voltage with a zero temperature coefficient.

The advantages of the circuit shown in Figure 1 are its simple structure and low operating voltage. However, the channel length modulation effects of the mirror transistors M1 to M4 are different, resulting in different currents of the mirror transistors M1 and M2, which will cause the output reference voltage Vbg to have a large temperature coefficient, that is, the voltage is easily affected by temperature, while the reference voltage Vbg The size will vary with the supply voltage.

In order to counteract the channel length modulation effect of the transistors, as shown in FIG. 2 , mirror transistors M5 to M8 are usually added to the voltage branch of the positive temperature coefficient, wherein the mirror transistors M5 and M6 are used to clamp the mirror transistors M1 and M2 The drain voltage is to ensure that the drain voltages of the mirror transistors M1 and M2 are the same, and to cancel the channel length modulation effect of the mirror transistors M1 and M2. Similarly, the mirror transistors M7 and M8 are used to clamp the drain voltages of the mirror transistors M3 and M4 to ensure that the drain voltages of the mirror transistors M3 and M4 are the same, and to cancel the channel length modulation effect of the mirror transistors M3 and M4.

Compared with the circuit shown in FIG. 1 , in the circuit structure shown in FIG. 2 , since the transistors M5 to M8 are connected in series on the branch where the transistors M1 to M4 are located, the power supply voltage VDD for the normal operation of the circuit is larger.

The present application provides a bandgap reference circuit and an integrated circuit, and aims to provide a bandgap-free reference circuit capable of canceling the modulation effect of the transistor channel length and having a low operating voltage. The inventive concept of the present application is to clamp the voltage of the transistor by introducing feedback, so as to cancel the influence of the channel length modulation effect of the transistor on the voltage of the transistor.

The bandgap reference circuit provided by the present application can be applied to an integrated circuit to provide a bandgap reference voltage for the integrated circuit. The bandgap reference voltage remains constant and does not change with temperature.

As shown in FIG. 3 , an embodiment of the present application provides a bandgap reference circuit 100 including a reference voltage circuit 10 and a feedback branch 20 .

The reference voltage circuit 10 includes a first switch transistor group Z1 and a second switch transistor group Z2. The first switch transistor group Z1 and the second switch transistor group Z2 are mirror transistor groups, that is, the first switch transistor group Z1 and the second switch transistor group Z1. The structure of the switch transistor group Z2 is the same, and the currents flowing through the corresponding switch transistors in the first switch transistor group Z1 and the second switch transistor group Z2 are the same, and the corresponding switch transistors in the first switch transistor group Z1 and the second switch transistor group Z2 are each. terminal voltage is the same. The structures of the first switch transistor group Z1 and the second switch transistor group Z2 are described from two aspects. The first aspect means that the corresponding switch transistors in the two switch transistor groups have the same structure, and the second aspect means that the connection relationship between the respective ends of the corresponding switch transistors in the two switch transistor groups is the same.

The feedback branch 20 is connected to the reference voltage circuit 10, the reference voltage circuit 10 is used to provide a voltage with zero temperature coefficient, the first switch transistor group Z1 and the second switch transistor group Z2 are both used to provide constant current, and the feedback branch 20 The voltages of the first switch transistor group Z1 and the second switch transistor group Z2 are clamped by introducing a feedback signal into the reference voltage circuit 10 .

The working principle of the bandgap reference circuit is described below: the reference voltage circuit outputs a voltage with zero temperature coefficient, and the switches in the first switch group Z1 and the second switch group Z2 have different degrees of channel length modulation effects, that is, two The currents of the switches in the switch groups are different, so that the voltages at both ends of the corresponding switches in the first switch group Z1 and the second switch group Z2 are different. The feedback branch 20 introduces a feedback signal to the reference voltage circuit 10 to clamp The voltages of the first switch transistor group Z1 and the second switch transistor group Z2 are set, so that the voltages at the two ends of the corresponding switch transistors in the first switch transistor group Z1 and the second switch transistor group Z2 remain the same, thereby making the output voltage of the reference voltage circuit 10 The size of the reference voltage circuit 10 does not change, and the output voltage of the reference voltage circuit 10 is still a voltage with zero temperature coefficient, that is, it does not change with the temperature change.

In the bandgap reference circuit provided by the embodiment of the present application, the voltage of the switch tube is clamped by introducing the feedback signal from the feedback branch to cancel the channel length modulation effect of the switch tube, so that the output voltage of the reference voltage circuit remains at zero temperature coefficient voltage. The method of feedback signal eliminates the channel length modulation effect of the switch tube. Compared with the bandgap reference circuit shown in Figure 2, the amplitude of the power supply voltage required by the bandgap reference circuit in this application is the same as that of the bandgap reference circuit shown in Figure 1. More integrated circuits are applicable, thereby expanding the scope of circuit use.

Another embodiment of the present application provides a bandgap reference circuit including a reference voltage circuit and a feedback branch.

As shown in FIG. 4 , the reference voltage circuit includes a first switch transistor group Z1 and a second switch transistor group Z2. The first switch transistor group Z1 includes a first switch transistor T1 and a second switch transistor T2. The second switch transistor group Z2 includes a third switch transistor T3 and a fourth switch transistor T4.

Each switch tube is provided with a first end, a second end and a control end. When the switch tube is working, the current flowing from the first end to the second end is controlled by the control end.

The first switch tube T1 and the third switch tube T3 are mirror transistors, and the second switch tube T2 and the fourth switch tube T4 are mirror transistors. The mirror transistor means that the two transistors have the same structure and are connected in the same way. The current flowing through the two transistors and the voltage at each terminal are also the same.

The second end of the first switch tube T1 is connected to the first end of the second switch tube T2, that is, the first switch tube T1 and the second switch tube T2 are connected in series. The second end of the third switch tube T3 is connected to the first end of the fourth switch tube T4, that is, the third switch tube T3 and the fourth switch tube T4 are connected in series.

The control terminal of the third switch tube T3 is connected to the control terminal of the first switch tube T1, and the voltage of the third switch tube T3 is clamped by short-circuiting the second terminal and the control terminal of the third switch tube T3. The feedback circuit 20 forms a feedback signal according to the output signal of the first end of the second switch tube T2, and introduces the feedback signal to the control end of the second switch tube T2 to clamp the voltage of the second switch tube T2. In addition, the control terminal of the second switch tube T2 is connected to the control terminal of the fourth switch tube T4, thereby clamping the voltage of the fourth switch tube T4.

The working principle of the bandgap reference circuit is described below: when the reference voltage circuit outputs a voltage with zero temperature coefficient, the first switch transistor T1 to the fourth switch transistor T4 have different degrees of channel length modulation effects, so that the first switch transistor T1 and the fourth switch transistor T4 have different degrees of channel length modulation effects. The current in the branch where the second switch transistor T2 is located is different from the branch where the first switch transistor T3 and the second switch transistor T4 are located, and the voltages of the first end of the second switch transistor T2 and the first end of the fourth switch transistor T4 are different.

A feedback signal is introduced through the feedback branch to clamp the voltage of the second switch tube T2. In addition, the second switch T2 and the fourth switch T4 are mirror switches, and the control terminal of the second switch T2 is connected to the control terminal of the fourth switch T4 to clamp the voltage of the fourth switch T4. The series connection of the first switch transistor T1 and the second switch transistor T2 can further clamp the voltage of the first switch transistor T1. The second terminal of the third switch tube T3 is short-circuited with the control terminal, the third switch tube T3 is equal to the voltage after the switch tube is turned on, and the voltage of the third switch tube T3 also remains unchanged.

In the bandgap reference circuit provided by the embodiment of the present application, by introducing a feedback current into the second switch tube, the voltage clamping of the first switch tube, the second switch tube and the fourth switch tube is realized, and the third switch tube is short-circuited. connected, the voltage at both ends remains unchanged, thereby realizing the clamping of all switch tube voltages, offsetting the channel length modulation effect of the switch tubes, so that the output voltage of the reference voltage circuit remains zero temperature coefficient voltage, and the feedback signal can be used to achieve no Increase the operating voltage of the circuit.

As shown in FIG. 5 , another embodiment of the present application provides a bandgap reference circuit including a reference voltage circuit and a feedback branch 20 .

The reference voltage circuit is described below. The reference voltage circuit includes a reference current circuit 101 and an output circuit 102 . The reference current circuit 101 is connected to the output circuit 102, the reference current circuit 101 is used for providing a current with zero temperature coefficient, and the output circuit 102 is used for converting the current with zero temperature coefficient into a voltage output with zero temperature coefficient.

The reference current circuit 101 includes: a first switch transistor group Z1 , a second switch transistor group Z2 , a positive temperature coefficient current branch 1011 and a negative temperature coefficient current branch 1012 . The first switch transistor group Z1 and the second switch transistor group Z2 are both connected to the input end of the positive temperature coefficient current branch 1011, the output end of the positive temperature coefficient current branch 1011 is connected to the first input end of the output circuit 101, and the negative temperature The output terminal of the coefficient current branch 103 is connected to the second input terminal of the output circuit 101 .

The first switch transistor group Z1 and the second switch transistor group Z2 are used to provide constant current for the positive temperature coefficient current branch 1011 . The positive temperature coefficient current branch 1011 is used to provide a positive temperature coefficient current, the negative temperature coefficient current branch 1012 is used to provide a negative temperature coefficient current, and the output circuit 102 is used to superimpose the positive temperature coefficient current and the negative temperature coefficient current After getting the current with zero temperature coefficient, convert the current with zero temperature coefficient into voltage output with zero temperature coefficient.

The positive temperature coefficient current branch 1011 further includes a first current branch 1013 and a second current branch 1014, and the first current branch 1013 and the second current branch 1014 are connected in parallel. The first current branch 1013 further includes a fifth switch tube T5, and the fifth switch tube T5 is connected in series with the first switch tube group Z1, that is, the first end of the fifth switch tube T5 and the second end of the second switch tube T2 connect. The second end of the first switch tube T2 is connected to the first end of the second switch tube T2, the first end of the first switch tube T1 is connected to the power supply VDD, and the control end of the fifth switch tube T5 is shorted to the second end and grounded .

The second current branch 1012 further includes a third switch transistor group Z3 and a sixth resistor R6. The third switch transistor group Z3 includes a plurality of sixth switch transistors T6 connected in parallel. That is, the first end of each sixth switch tube T6 is connected to each other, the second end of each sixth switch tube T6 is connected to each other, and the control end of each sixth switch tube T6 is connected to each other. The control end of the sixth switch tube T6 is short-circuited with the second end. The third switch transistor group Z3 is connected in series with the second switch transistor group Z2 through a sixth resistor R6. That is, the second end of the fourth switch tube T4 is connected to the first end of the sixth switch tube T6 through the sixth resistor R6. The second end of the third switch transistor T3 is connected to the first end of the fourth switch transistor T4, and the first end of the third switch transistor T3 is connected to the power supply VDD.

The negative temperature coefficient current branch 1012 further includes a second resistor R2 and a third resistor R3, the second resistor R3 is connected to the second end of the fifth switch tube T2, and the other end of the second resistor R2 is grounded. One end of the third resistor R3 is connected to the second end of the fourth switch tube T4, and the other end of the third resistor R3 is grounded.

The output circuit 102 further includes a tenth switch transistor T10 and a fourth resistor R4. The first end of the tenth switch tube T10 is connected to the power supply VDD, the control end of the tenth switch tube T10 is connected to the first end of the second switch tube T2, and the second end of the tenth switch tube T10 is connected to one end of the fourth resistor R4 connected, and the other end of the fourth resistor R4 is grounded.

The following analyzes the principle that the reference voltage circuit provides the bandgap reference voltage:

The first switch transistor T1 and the third switch transistor T3 are mirror transistors, and the second switch transistor T2 and the fourth switch transistor T4 are also mirror transistors. The third switch transistor group Z3 includes a plurality of sixth switch transistors T6 connected in parallel. Then the current in the sixth resistor R6 satisfies the formula (1). That is, the current in the sixth resistor R6 is a current with a positive temperature coefficient.

The voltage across the second resistor R2 is the voltage across the fifth switch tube T5, so the current flowing through the second resistor R2 is:

Wherein, Vbe represents the voltage across the fifth switch transistor T5, R2 represents the resistance value of the second resistor, and the voltage Vbe across the fifth switch transistor T5 is a voltage with a negative temperature coefficient.

In addition, the resistance values of the second resistor R2 and the third resistor R3 are the same, and the current of the third resistor R3 also conforms to the formula (3). It can be known from formula (3) that the currents of the second resistor R2 and the third resistor R3 are currents with negative temperature coefficients.

Therefore, the current flowing through the first switch tube T1 is:

Among them, Vbe is a negative temperature coefficient voltage, ΔVbe is a positive temperature coefficient voltage, and by adjusting the ratio of R2 and R6, Ibg can be made a current with zero temperature coefficient.

The tenth switch tube T10 and the first switch tube T1 constitute a mirror switch tube, and the tenth switch tube T10 mirrors the current in the first switch tube T1, that is, the current in the tenth switch tube T10 is equal to the current in the first switch tube T1, and after the fourth switch tube T10 After resistor R4, the output voltage of the output circuit is:

Since Ibg has a zero temperature coefficient of current, Vbg has a zero temperature coefficient of voltage.

In addition, the amplitude of the output bandgap reference voltage can be adjusted by adjusting the resistance value of the fourth resistor R4, so that the bandgap reference voltage with a lower amplitude can be output.

The feedback branch 20 is described below. The feedback branch 20 includes a seventh switch transistor T7, an eighth switch transistor T8 and a ninth switch transistor T9.

The second end of the seventh switch tube T7 is connected to the first end of the eighth switch tube T8, the second end of the eighth switch tube T8 is connected to the first end of the ninth switch tube T9, and the seventh switch tube T7 is connected to the first end of the ninth switch tube T9. The first terminal is connected to the power supply VDD, and the second terminal of the ninth switch transistor T9 is grounded, so as to realize the series connection of the seventh switch transistor T7, the eighth switch transistor T8 and the ninth switch transistor T9.

The control end of the seventh switch tube T7 is connected to the first end of the second switch tube T2 to form a feedback signal according to the output signal of the first end of the second switch tube T2. The first end of the eighth switch tube T8 is short-circuited with the control end, and the second end of the ninth switch tube T9 is short-circuited with the control end, so that the structure of the feedback branch 20 is the same as that of the first current branch 1013, the negative temperature coefficient current The circuit structure of the branch 1012 and the first switch tube group Z1 is similar, and the first end of the eighth switch tube T8 is connected to the control end of the second switch tube T2 for introducing a feedback signal into the reference voltage circuit to realize the The voltage clamping of the two switches T2.

The following analyzes the principle that the feedback branch 20 realizes the voltage clamping by introducing the feedback signal:

The size of the eighth switch tube T8 is the same as that of the second switch tube T2 and the fourth switch tube T4, and the control terminal of the eighth switch tube T8 is short-circuited with the first terminal. The size of the seventh switch tube T7 is the same as that of the third switch tube T3 and the first switch tube T1. In addition, the second terminal of the ninth switch tube T9 is short-circuited with the control terminal, so that the feedback branch is similar in structure to the first current branch 1013, the negative temperature coefficient current branch 1012 and the first switch tube group Z1, and the seventh switch tube has a similar structure. T7 and the third switch tube T3 constitute a mirror switch tube, and the current of the seventh switch tube T7 is the same as the current of the third switch tube T3, thereby ensuring that the voltages at both ends of the seventh switch tube T7 and the third switch tube T3 are the same, and the seventh switch tube T7 has the same voltage as the third switch tube T3. The control end of the switch tube T7 is connected to the first end of the second switch tube T2, and the second end of the seventh switch tube T7 is connected to the control end of the second switch tube T2 to form a loop, thereby ensuring that the first switch tube T1 and the The voltages of the second terminals of the third switch transistor T3 are completely the same, so that the channel length modulation effects of the first switch transistor T1 and the third switch transistor T3 are completely canceled, and the currents of the first switch transistor T1 and the third switch transistor T3 are completely consistent. In addition, the voltage of the first terminal of the second switch tube T2 is equal to the voltage of the second terminal of the first switch tube T1, and the voltage of the first terminal of the fourth switch tube T4 is equal to the voltage of the second terminal of the third switch tube T3, which flows through the second switch tube. The currents of the transistor T2 and the fourth switch transistor T4 are the same, the second terminal voltage of the second switch transistor T2 and the second terminal voltage of the fourth switch transistor T4 are also the same, and the channel lengths of the second switch transistor T2 and the fourth switch transistor T4 Modulation effects are also canceled.

Preferably, the first switch transistor T1, the third switch transistor T3 and the seventh switch transistor T7 are P-type field effect transistors, and the second switch transistor T2, the fourth switch transistor T4 and the eighth switch transistor T8 are N-type field effect transistors , the fifth switch tube T5, the sixth switch tube T6 and the ninth switch tube T9 are triode tubes. When the switch tube is a P-type field effect transistor, the first end of the switch tube is the source of the field effect transistor, the second end of the switch tube is the drain of the field effect transistor, and the control end of the switch tube is the gate of the transistor. When the switch tube is an N-type field effect transistor, the first end of the switch tube is the drain of the field effect transistor, the second end of the switch tube is the source of the field effect transistor, and the control end of the switch tube is the gate of the transistor. When the switch tube is a triode, the first end of the switch tube is the emitter of the triode, the second end of the switch tube is the collector of the triode, and the control end of the switch tube is the base of the triode. By making the structure of the feedback branch similar to the first current branch 1013 , the negative temperature coefficient current branch 1012 and the first switch transistor group Z1 , the transistor voltage clamping is realized.

Preferably, as shown in FIG. 6 , the feedback branch further includes: a first resistor R1, and the first resistor R1 is connected in parallel with the ninth switch transistor T9. In order to realize that the feedback branch has the same structure as the branch formed by the first DC current 1013, the negative temperature coefficient current branch 1012 and the first switch tube group Z1, the output signal of the first end of the second switch tube T2 is transmitted through the feedback branch. The control terminal of the second switch tube T2 is introduced to further improve the accuracy of the voltage clamping voltage of the transistor, so as to offset the channel length modulation effect of the switch tube.

In the bandgap reference circuit provided by the embodiment of the present application, by making the feedback branch similar to or the same as the branch formed by the first current branch, the negative temperature coefficient current branch and the first switch tube group, the first The voltage clamping in the switch tube group and the second switch tube group ensures that the output voltage of the reference voltage circuit has a zero temperature coefficient voltage. And the working voltage of the circuit is not increased by means of the feedback signal.

As shown in FIG. 7 , a bandgap reference circuit provided by another embodiment of the present application includes a reference voltage circuit and a feedback branch 20 .

The reference voltage circuit includes a reference current circuit and an output circuit. The reference current circuit further includes a positive temperature coefficient current branch 1011 and a negative temperature coefficient current branch 1012 . The functions of the reference current circuit and the output circuit 102, and the functions of the positive temperature coefficient current branch 1011 and the negative temperature coefficient current branch 1012 are the same as those of the embodiment shown in FIG. 4, and will not be repeated here.

In addition, the circuit structure of the positive temperature coefficient current branch 1011 is similar to the circuit structure of the positive temperature coefficient current branch 1011 in the embodiment shown in FIG. 4 , and details are not repeated here.

The circuit structure of the negative temperature coefficient current branch 1012 and the circuit structure of the output circuit 102 are described below. The negative temperature coefficient current branch further includes an eleventh switch transistor T11. Wherein, the control terminal of the eleventh switch tube T11 is short-circuited with the second terminal and grounded. The voltage across the eleventh switch tube T11 is a voltage with a negative temperature coefficient.

The output circuit further includes a fifth resistor R5 and a twelfth switch tube T12. The first end of the twelfth switch tube T12 is connected to the power supply VDD, and the control end of the twelfth switch tube T12 is connected to the first end of the second switch tube T2. Connection, the second end of the twelfth switch tube T12 is connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the first end of the eleventh switch tube T11.

The twelfth switch tube T12 mirrors the current in the first switch tube T2, that is, the current in the twelfth switch tube T12 is the same as the current in the first switch tube T1, and passes through the fifth resistor R5 and the eleventh switch tube T11 to output Voltage with zero temperature coefficient.

The feedback branch is composed of the seventh switch tube T7, the eighth switch tube T8 and the ninth switch tube T9 connected in series in sequence. The feedback branch 20 has the same structure as the first current branch 1013 and the first switch tube group Z1. The output signal of the first end of the two switch transistors T2 is introduced into the control end of the second switch transistor T2 after passing through the feedback branch, which further improves the accuracy of the voltage clamping voltage of the transistor to offset the channel length modulation effect of the switch transistor.

In the bandgap reference circuit provided in the embodiment of the present application, the voltages in the first switch transistor group and the second switch transistor group are clamped by introducing a feedback signal, so as to ensure that the output voltage of the reference voltage circuit has a zero temperature coefficient voltage, and Does not increase the operating voltage of the circuit.

Those of ordinary skill in the art can understand that all or part of the steps of implementing the above method embodiments may be completed by program instructions related to hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps including the above method embodiments are executed; and the foregoing storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: The technical solutions described in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present invention. scope.

Claims

A bandgap reference circuit, comprising: a reference voltage circuit and a feedback branch (20);

The feedback branch (20) is connected to the reference voltage circuit, and the reference voltage circuit includes a first switch tube group (Z1) and a second switch tube group (Z2), the first switch tube group (Z1) and the second switch tube group (Z2) is a mirror transistor group;

The reference voltage circuit is used for providing a voltage with zero temperature coefficient, the first switch transistor group (Z1) and the second switch transistor group (Z2) are used for providing a constant current, and the feedback branch (20) passes through A feedback signal is introduced into the reference voltage circuit to clamp the voltages of the first switch transistor group (Z1) and the second switch transistor group (Z2).
The bandgap reference circuit according to claim 1, wherein the first switch transistor group (Z1) comprises a first switch transistor (T1) and a second switch transistor (T2);

The second end of the first switch tube (T1) is connected to the first end of the second switch tube (T2);

The feedback circuit (20) is configured to form the feedback signal according to the output signal of the first end of the second switch tube (T2), and introduce the feedback to the control end of the second switch tube (T2) signal to clamp the voltage of the second switch tube (T2).
The bandgap reference circuit according to claim 2, wherein the second switch transistor group (Z2) comprises a third switch transistor (T3) and a fourth switch transistor (T4);

The second end of the third switch tube (T3) is connected to the first end of the fourth switch tube (T4);

The second end and the control end of the third switch tube (T3) are short-circuited, and the control end of the third switch tube (T3) is connected with the control end of the first switch tube (T1) to clamp all the the voltage of the third switch tube (T3).
The bandgap reference circuit according to claim 3, wherein the control terminal of the second switch tube (T2) is connected to the control terminal of the fourth switch tube (T4) to clamp the fourth switch tube (T4). The voltage of the switch tube (T4).
The bandgap reference circuit according to claim 4, wherein the feedback branch (20) comprises: a seventh switch transistor (T7), an eighth switch transistor (T8) and a ninth switch transistor (T9);

Wherein, the second end of the seventh switch tube (T7) is connected to the first end of the eighth switch tube (T8), and the second end of the eighth switch tube (T8) is connected to the ninth switch The first end of the tube (T9) is connected;

The control end of the seventh switch tube (T7) is connected to the first end of the second switch tube (T2), so as to form the feedback according to the output signal of the first end of the second switch tube (T2) Signal;

The first end of the eighth switch tube (T8) is connected to the control end of the second switch tube (T2) to introduce the feedback signal.
The bandgap reference circuit according to claim 5, wherein the first end of the eighth switch tube (T8) is short-circuited with the control end, and the second end of the ninth switch tube (T9) is connected with the control end The terminals are short-circuited, so that the voltage of the first terminal of the eighth switch tube (T8) is the same as the voltage of the first terminal of the second switch tube (T2).
The bandgap reference circuit according to claim 5 or 6, wherein the feedback branch further comprises: a first resistor (R1), the first resistor (R1) and the ninth switch transistor (T9) )in parallel.
The bandgap reference circuit according to any one of claims 1 to 6, wherein the reference voltage circuit comprises: a reference current circuit (101) and an output circuit (102);

The reference current circuit (101) is connected to the output circuit (102), the reference current circuit (101) is used for providing a current with zero temperature coefficient, and the output circuit (102) is used for converting the zero temperature coefficient The current is converted to the zero temperature coefficient voltage output.
The bandgap reference circuit according to claim 8, wherein the reference current circuit (101) further comprises: a positive temperature coefficient current branch (1011), and the positive temperature coefficient current branch (1011) is used to provide positive temperature coefficient of current;

The positive temperature coefficient current branch (1011) further comprises a first current branch (1013) and a second current branch (1014) connected in parallel;

The first current branch (1013) further includes a fifth switch tube (T5), and the fifth switch tube (T5) is connected in series with the first switch tube group (Z1);

The second current branch further includes a third switch tube group (Z3) and a sixth resistor (R6), the second switch tube group (Z2), the sixth resistor (R6) and the third switch tube group (Z3) ) are connected in series in sequence;

The third switch tube group (Z3) includes a plurality of sixth switch tubes (T6) connected in parallel.
The bandgap reference circuit according to claim 9, wherein the reference current circuit (101) comprises: a negative temperature coefficient current branch (1012) for providing a current with a negative temperature coefficient;

The negative temperature coefficient current branch (1012) further includes a second resistor (R2) and a third resistor (R3);

One end of the second resistor (R2) is connected to the second end of the second switch tube (T2), the other end of the second resistor (R2) is grounded, and one end of the third resistor (R3) is connected to the The fourth switch tube (T4) is connected, the other end of the third resistor (R3) is connected to ground, and both the second resistor (R2) and the third resistor (R3) are used to provide a current with a negative temperature coefficient.
The bandgap reference circuit according to claim 10, wherein the output circuit comprises a tenth switch transistor (T10) and a fourth resistor (R4);

Wherein, the first end of the tenth switch tube (T10) is connected to the power supply, the control end of the tenth switch tube (T10) is connected to the first end of the second switch tube (T2), the The second end of the ten switch tube (T10) is connected to one end of the fourth resistor (R4), and the other end of the fourth resistor (R4) is grounded.
The bandgap reference circuit according to claim 9, wherein the reference current circuit comprises: a negative temperature coefficient current branch for providing a current with a negative temperature coefficient;

The negative temperature coefficient current branch further includes an eleventh switch tube (T11), and the control end of the eleventh switch tube (T11) is short-circuited with the second end and grounded.
The bandgap reference circuit according to claim 12, wherein the output circuit comprises a fifth resistor (R5) and a twelfth switch transistor (T12);

Wherein, the first end of the twelfth switch tube (T12) is connected to the power supply, and the control end of the twelfth switch tube (T12) is connected to the first end of the second switch tube (T2), so The second end of the twelfth switch tube (T12) is connected to one end of the fifth resistor (R5), and the other end of the fifth resistor (R5) is connected to the first end of the eleventh switch tube (T11). connected at one end.
An integrated circuit, characterized by comprising the bandgap reference circuit according to any one of claims 1 to 13.