CN103677031B - Method and circuit for providing zero-temperature coefficient voltage and zero-temperature coefficient current - Google Patents

Abstract

The invention discloses a method and a circuit for providing voltage and current with zero temperature coefficient. The circuit includes a first bipolar transistor, a second bipolar transistor, a first transistor, a second transistor, an operational amplifier, a first resistor, and a second transistor. Two resistors, a third resistor, and a fourth resistor; the collector and base of the first bipolar transistor are grounded, and the emitter is connected to one end of the second resistor and the inverting input of the operational amplifier; the collector of the second bipolar transistor The electrode and the base are grounded, the emitter is connected to one end of the first resistor, the other end of the first resistor is connected to one end of the third resistor and the non-inverting input end of the operational amplifier; the drain of the first transistor is connected to the other end of the second resistor, The other end of the third resistor, one end of the fourth resistor, and the other end of the fourth resistor are grounded; the gate of the first transistor and the gate of the second transistor are connected to the output terminal of the operational amplifier; the source of the first transistor and the second The source of the transistor is connected to the power supply. The invention can simultaneously provide voltage and current with zero temperature coefficient.

Description

A method and circuit for providing voltage and current with zero temperature coefficient

technical field

The invention relates to the field of integrated circuit design, in particular to a method and circuit for providing voltage and current with zero temperature coefficient.

Background technique

The bandgap reference source circuit is widely used in analog circuits. The bandgap reference source circuit can provide a voltage independent of process, voltage and temperature. This voltage can be used in temperature detection circuits, data converters, and low dropout linear voltage regulators. devices and other circuits.

In the existing technical implementation, the VBE voltage difference obtained by two transistors with different current densities with positive temperature characteristics is mainly used, and the voltage is added to a low temperature coefficient resistor (the temperature coefficient of which is the same as the temperature coefficient of the VBE voltage difference In comparison, a current proportional to the temperature is obtained, and then the current is sent to a low temperature coefficient resistor of the same type to obtain a voltage with a positive temperature coefficient, which is the same as the VBE voltage with a negative temperature coefficient of the triode Added together, a zero temperature coefficient voltage is obtained.

Under the deep sub-micron process, the integration level of the chip is getting higher and higher, and the power consumption is also increasing, which makes the operating temperature of the chip change greatly, so that the operating current in the circuit also changes with the temperature change. The current technology only A voltage with zero temperature coefficient can be provided, but a current with zero temperature coefficient cannot be obtained at the same time.

Contents of the invention

In order to solve the above defects in the prior art, the present invention proposes a method and circuit for providing zero temperature coefficient voltage and current, which can simultaneously provide zero temperature coefficient voltage and zero temperature coefficient circuit.

One aspect of the present invention provides a bandgap reference source circuit, characterized in that it includes a first bipolar transistor, a second bipolar transistor, a first transistor, a second transistor, an operational amplifier, a first resistor, The second resistor, the third resistor, and the fourth resistor; wherein,

The collector and the base of the first bipolar transistor are grounded, and the emitter is connected to one end of the second resistor and the inverting input end of the operational amplifier;

The collector and base of the second bipolar transistor are grounded, the emitter is connected to one end of the first resistor, and the other end of the first resistor is connected to one end of the third resistor and the positive terminal of the operational amplifier. phase input;

The drain of the first transistor is connected to the other end of the second resistor, the other end of the third resistor, and one end of the fourth resistor, and the other end of the fourth resistor is grounded;

The gate of the first transistor and the gate of the second transistor are connected to the output terminal of the operational amplifier; the source of the first transistor and the source of the second transistor are connected to a power supply; the second The drain terminal of the transistor is the zero temperature coefficient current output terminal;

The first resistor, the second resistor, and the third resistor are resistors with a positive temperature coefficient or a resistor with a negative temperature coefficient, the fourth resistor is a resistor with a positive temperature coefficient, and the positive temperature coefficient of the fourth resistor is greater than the Describe the absolute values of the temperature coefficients of the first resistor, the second resistor, and the third resistor.

As a preference of the above technical solution, the resistance values of the second resistor and the third resistor are equal.

As a preference of the above technical solution, the fourth resistor is replaced by a fifth resistor and a sixth resistor connected in series.

As a preference of the above technical solution, a seventh resistor is further included, and the seventh resistor is connected between the first transistor, the second resistor, and the third resistor.

As a preference of the above technical solution, the first transistor and the second transistor are MOS field effect transistors or bipolar transistors.

The present invention also proposes a method for providing zero temperature coefficient voltage and current, including providing the aforementioned bandgap reference source circuit, and further comprising the following steps:

Set the non-inverting and inverting inputs of the error amplifier to have equal voltages;

adjusting the first resistor, the second resistor and the third resistor so that the voltage of the positive temperature coefficient on the second resistor is added to the voltage of the negative temperature coefficient of the first bipolar transistor to obtain the first voltage of zero temperature coefficient;

The fourth resistor is adjusted so that the current with a negative temperature coefficient passing through the fourth resistor is added to the current with a positive temperature coefficient of the first bipolar transistor and the second bipolar transistor to obtain a current with a zero temperature coefficient.

As a preference of the above technical solution, when the fourth resistor is replaced by a fifth resistor and a sixth resistor in series, the method further includes:

The relative sizes of the fifth resistor and the sixth resistor are adjusted to obtain a second voltage with zero temperature coefficient ranging between 0V and the first voltage.

The present invention obtains a current with a negative temperature coefficient by using the positive temperature coefficient resistor R4, and the current is added to the PTAT current to obtain a current with a zero temperature coefficient; using the generated positive temperature coefficient current, by properly setting the resistors R1, R2, and R3 The zero temperature coefficient voltage VBG can be obtained; and VBG is not affected by the resistance R4; in actual preparation, the device will deviate from the design value, and the zero temperature coefficient voltage can be obtained by fine-tuning R1, R2, and R3; by fine-tuning The size of R4 can get zero temperature coefficient current; the bandgap reference voltage less than 1V can be obtained by dividing the voltage of resistors R4A and R4B; by adjusting the ratio of R4A and R4B, the reference voltage output of multiple amplitudes can be realized, and the better flexibility.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the description, and are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the attached picture:

1 is a structural diagram of a bandgap reference source circuit proposed by an embodiment of the present invention;

FIG. 2 is a structural diagram of another bandgap reference source circuit proposed by an embodiment of the present invention;

3 is a structural diagram of another bandgap reference source circuit proposed by an embodiment of the present invention;

FIG. 4 is a flowchart of a method for providing zero temperature coefficient voltage and current in an embodiment of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

As shown in Figure 1, the bandgap reference source circuit proposed by the embodiment of the present invention includes:

A first bipolar transistor Q1, a second bipolar transistor Q2, a first transistor M1, a second transistor M2, an operational amplifier A, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4; in:

The collector and base of the first bipolar transistor Q1 are grounded, and the emitter is connected to one end of the second resistor R2 and the inverting input terminal VN of the operational amplifier A;

The collector and the base of the second bipolar transistor Q2 are grounded, the emitter is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to one end of the third resistor R3 and the non-inverting input terminal VP of the operational amplifier A;

The drain of the first transistor M1 is connected to the other end of the second resistor R2, the other end of the third resistor R3, and one end of the fourth resistor R4, and the other end of the fourth resistor R4 is grounded;

The gate of the first transistor M1 and the gate of the second transistor M2 are connected to the output terminal of the operational amplifier A; the source of the first transistor M1 and the source of the second transistor M2 are connected to the power supply VDD; the drain of the second transistor M2 is Zero temperature coefficient current output;

Wherein, the first resistor R1, the second resistor R2, and the third resistor R3 are resistors with a positive temperature coefficient or a resistor with a negative temperature coefficient, and the fourth resistor R4 is a resistor with a positive temperature coefficient, and the positive temperature coefficient of the fourth resistor R4 is greater than The absolute values of the temperature coefficients of the first resistor R1, the second resistor R2, and the third resistor R3.

In the following, the principle of the bandgap reference source circuit proposed in the embodiment of the present invention will be described in detail:

First make the following assumptions:

1. The gain of the error amplifier A is large enough, and the input impedance is infinite, so that the voltages of the VP and VN points are equal;

2. Ignore mismatches in the circuit, such as mismatches between resistors, mismatches between transistors, and mismatches between bipolar transistors.

The relationship between the collector current of a bipolar transistor and its emitter-base voltage is:

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

Among them, I _s is the saturation current of the bipolar transistor, V _T is the thermal voltage, V _T =KT/q; K is the Boltzmann constant, T is the absolute temperature, q is the electronic charge, and V _EB is the bipolar The emitter-base voltage of a transistor.

The current in a bipolar transistor is:

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; e</span>}}^{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Wherein, I _C =I _B ×β _F , I _B is the base current of the bipolar transistor, and β _F is the DC amplification factor.

Therefore, the emitter-base voltage of a bipolar transistor is:

${\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; ln</span>}<span\; class="notranslate">\; (</span>\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}}}{<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; /</span>{\mathrm{<span\; class="notranslate">\; \&beta;</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&times;</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In Figure 1, resistors R2 and R3 are equal in size, and the voltages of the positive and negative input terminals of error amplifier A are also equal, so the currents in resistors R2 and R3 are equal; therefore, in the first bipolar transistor Q1 and the second bipolar transistor Q2 The currents I _Q1 and I _Q2 are equal, and the difference between the emitter-base voltage of the two is

${\mathrm{<span\; class="notranslate">\; \&Delta;V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}}\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; ln</span>}\frac{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}{{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In formula (4), it is assumed that the ratio of the emitter areas of the first bipolar transistor Q1 and the second bipolar transistor Q2 is 1:N, so the ratio of the saturation current of the two is:

I _s1 :I _s2 =1:N (5)

Therefore, the difference between the emitter-base voltages of the first bipolar transistor Q1 and the second bipolar transistor Q2 is:

ΔV _EB ＝V _T ·lnN (6)

It can be seen from Figure 1 that the current in the first bipolar transistor Q1 and the second bipolar transistor Q2 is equal to the current in the resistor R1:

${\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; \&Delta;V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}}}{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; ln</span>}\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

It can be seen that the current I _Q1 of the first bipolar transistor Q1 and the current I Q2 of the second bipolar transistor _Q2 are currents with positive temperature coefficients.

The output voltage VBG is:

$\mathrm{<span\; class="notranslate">\; VBG</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; Q</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; EB</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; T</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; ln</span>}\mathrm{<span\; class="notranslate">\; N</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

where V _EB1 is the voltage with a negative temperature coefficient of the first bipolar transistor Q1, A voltage with a positive temperature coefficient proportional to the temperature is generated. By properly setting the resistance values of the resistors R1, R2, and R3, a zero temperature coefficient voltage VBG can be obtained, and VBG is not affected by the resistor R4.

Because the transistors M1 and M2 are equal in size, their currents are also equal, which is the sum of the current I _Q1 of the first bipolar transistor Q1, the current I _Q2 of the second bipolar transistor Q2, and the current I _R4 in the resistor R4:

IM1＝IM2＝I _Q1 +I _Q2 +I _R4 (9)

Wherein, the current I _Q1 of the first bipolar transistor Q1 and the current I _Q2 of the second bipolar transistor Q2 are currents with a positive temperature coefficient, and the current I _R4 in the resistor R4 is a current with a negative temperature coefficient. By properly selecting the size of R4, The zero temperature coefficient current can be obtained, and the current in the transistor M1 is mirrored to the transistor M2. Therefore, the transistor M2 can be used to provide a zero temperature coefficient current without affecting the zero temperature coefficient voltage VBG.

In the embodiment shown in FIG. 2, the above-mentioned fourth resistor R4 is replaced by two series connected resistors R4A and R4B, thus, the voltage VBGLV on the resistor R4B can be obtained:

$\mathrm{<span\; class="notranslate">\; VBGLV</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; VBG</span>}<span\; class="notranslate">\; *</span>\frac{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; B</span>}}{\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; R</span>}\mathrm{<span\; class="notranslate">\; 4</span>}\mathrm{<span\; class="notranslate">\; B</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

The voltage VBGLV is also a voltage with zero temperature coefficient. By adjusting the relative size of R4A and R4B, the size of VBGLV can be adjusted to change between 0V and VBG.

In the embodiment shown in Figure 3, the bandgap reference source circuit is further improved, specifically, the bandgap reference source circuit includes:

The first bipolar transistor Q1, the second bipolar transistor Q2, the first transistor M1, the second transistor M2, the operational amplifier A, the first resistor R1, the second resistor R2, the third resistor R3, the fifth resistor R4A, The sixth resistor R4B, the seventh resistor R23; wherein:

The collector and base of the first bipolar transistor Q1 are grounded, and the emitter is connected to one end of the second resistor R2 and the inverting input terminal VN of the operational amplifier A; the other end of the second resistor R2 is connected to one end of the seventh resistor R23;

The collector and the base of the second bipolar transistor Q2 are grounded, the emitter is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to one end of the third resistor R3 and the non-inverting input terminal VP of the operational amplifier A; The other end of the third resistor R3 is connected to one end of the seventh resistor R23;

The drain of the first transistor M1 is connected to the other end of the seventh resistor R23 and one end of the fourth resistor R4A, the other end of the fifth resistor R4A is connected to one end of the sixth resistor R4B, and the other end of the sixth resistor R4B is grounded;

The gate of the first transistor M1 and the gate of the second transistor M2 are connected to the output terminal of the operational amplifier A; the source of the first transistor M1 and the source of the second transistor M2 are connected to the power supply VDD; the drain of the second transistor M2 is Zero temperature coefficient current output;

Wherein, the first resistor R1, the second resistor R2, and the third resistor R3 are resistors with a positive temperature coefficient or a resistor with a negative temperature coefficient, and the fourth resistor R4 is a resistor with a positive temperature coefficient, and the positive temperature coefficient of the fourth resistor R4 is greater than The absolute values of the temperature coefficients of the first resistor R1, the second resistor R2, and the third resistor R3.

After adding the seventh resistor R23, the total resistance size can be reduced and the chip area can be reduced, because when the same voltage drop is realized, the current flowing through R23 is the sum of the currents in resistors R2 and R3, so this can make the total resistance The resistance value decreases.

As shown in Figure 4, the method for providing zero temperature coefficient voltage and current proposed by the embodiment of the present invention includes providing the above-mentioned bandgap reference source circuit, and also includes the following steps:

Set the non-inverting and inverting inputs of the error amplifier to have equal voltages;

adjusting the first resistor, the second resistor and the third resistor so that the voltage of the positive temperature coefficient on the second resistor is added to the voltage of the negative temperature coefficient of the first bipolar transistor to obtain the first voltage of zero temperature coefficient;

The fourth resistor is adjusted so that the current with a negative temperature coefficient passing through the fourth resistor is added to the current with a positive temperature coefficient of the first bipolar transistor and the second bipolar transistor to obtain a current with a zero temperature coefficient.

Preferably, when the fourth resistor is replaced by a fifth resistor and a sixth resistor in series, the method further includes:

The relative sizes of the fifth resistor and the sixth resistor are adjusted to obtain a second voltage with zero temperature coefficient ranging between 0V and the first voltage.

The present invention obtains a current with a negative temperature coefficient by using a positive temperature coefficient resistor R4, and this current is added to the PTAT current to obtain a current with a zero temperature coefficient; using the generated positive temperature coefficient current, by properly setting the resistors R1, R2, and R3 The zero temperature coefficient voltage VBG can be obtained; and VBG is not affected by the resistance R4; in actual preparation, the device will deviate from the design value, and the zero temperature coefficient voltage can be obtained by fine-tuning R1, R2, and R3; by fine-tuning The size of R4 can get zero temperature coefficient current; the bandgap reference voltage less than 1V can be obtained by dividing the voltage of resistors R4A and R4B; by adjusting the ratio of R4A and R4B, the reference voltage output of multiple amplitudes can be realized, and the better flexibility.

It should be understood by those skilled in the art that various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (4)

1. A bandgap reference reference source circuit, characterized in that it comprises a first bipolar transistor, a second bipolar transistor, a first transistor, a second transistor, an operational amplifier, a first resistor, a second resistor, a second resistor Three resistors, the fourth resistor; where, The collector and the base of the first bipolar transistor are grounded, and the emitter is connected to one end of the second resistor and the inverting input end of the operational amplifier; The collector and base of the second bipolar transistor are grounded, the emitter is connected to one end of the first resistor, and the other end of the first resistor is connected to one end of the third resistor and the positive terminal of the operational amplifier. phase input; The drain of the first transistor is connected to the other end of the second resistor, the other end of the third resistor, and one end of the fourth resistor, and the other end of the fourth resistor is grounded; The gate of the first transistor and the gate of the second transistor are connected to the output terminal of the operational amplifier; the source of the first transistor and the source of the second transistor are connected to a power supply; the second The drain terminal of the transistor is the zero temperature coefficient current output terminal; Wherein, the first resistor, the second resistor, and the third resistor are resistors with a positive temperature coefficient or a resistor with a negative temperature coefficient, the fourth resistor is a resistor with a positive temperature coefficient, and the positive temperature coefficient of the fourth resistor is greater than the absolute value of the temperature coefficient of the first resistor, the second resistor, and the third resistor; Thus the zero temperature coefficient voltage VBG is obtained: , Wherein, V _EB1 is the voltage of the negative temperature coefficient of the first bipolar transistor Q1, wherein said R1 is the resistance value of the first resistor, and said R2 is the resistance value of the second resistor, is the thermal voltage, the ratio of the emitter areas of the first bipolar transistor Q1 and the second bipolar transistor Q2 is 1:N, Generates a voltage with a positive temperature coefficient proportional to temperature; The zero temperature coefficient current IM1 passing through the first transistor M1 and the zero temperature coefficient current IM2 of the second transistor M2 are respectively: IM1=IM2=I _Q1 +I _Q2 +I _R4 , Wherein, the current I _Q1 of the first bipolar transistor Q1 and the current I _Q2 of the second bipolar transistor Q2 are currents with a positive temperature coefficient, and the current I _R4 in the fourth resistor R4 is a current with a negative temperature coefficient; the second resistor The resistance value of the third resistor is equal, and the fourth resistor is replaced by the fifth resistor R4A and the sixth resistor R4B in series, thus, the voltage VBGLV on the sixth resistor R4B can be obtained: , Among them, the voltage VBGLV is also a voltage with zero temperature coefficient. By adjusting the relative size of R4A and R4B, the size of VBGLV can be adjusted to change between 0V and VBG; A seventh resistor is also included, and the seventh resistor is connected between the first transistor, the second resistor, and the third resistor. 2. The circuit according to claim 1, wherein the first transistor and the second transistor are MOS field effect transistors or bipolar transistors. 3. A method for providing zero temperature coefficient voltage and current is characterized in that, comprising providing the bandgap reference source circuit as claimed in claim 1, also comprising the following steps: Set the non-inverting and inverting inputs of the operational amplifier to have equal voltages; adjusting the first resistor, the second resistor and the third resistor so that the voltage of the positive temperature coefficient on the second resistor is added to the voltage of the negative temperature coefficient of the first bipolar transistor to obtain the first voltage of zero temperature coefficient; The fourth resistor is adjusted so that the current with a negative temperature coefficient passing through the fourth resistor is added to the current with a positive temperature coefficient of the first bipolar transistor and the second bipolar transistor to obtain a current with a zero temperature coefficient. 4. The method according to claim 3, wherein when the fourth resistor is replaced by a fifth resistor and a sixth resistor in series, the method further comprises: The relative sizes of the fifth resistor and the sixth resistor are adjusted to obtain a second voltage with zero temperature coefficient ranging between 0V and the first voltage.