CN104375554A - Bandgap reference circuit with function of bilateral temperature compensation - Google Patents

Abstract

The invention discloses a bandgap reference circuit with a function of bilateral temperature compensation. The bandgap reference circuit comprises a first-order compensation reference generating circuit, an error amplifier, a high- and low-temperature compensation transconductance amplifier and a compensating and dividing resistor. The first-order compensation reference generating circuit generates first-order compensation reference voltage and positive temperature coefficient voltage; the first-order compensation reference voltage is subjected to voltage division by the compensating and dividing resistor to generate high voltage and low voltage; the high voltage, the low voltage and the positive temperature coefficient voltage are input into the high- and low-temperature compensation transconductance amplifier; in a high temperature section and a low temperature section, the output end of the high- and low-temperature compensation transconductance amplifier extracts current from the outside; a compensating resistor on a reference voltage output branch generates compensating voltage. The bandgap reference circuit has the advantages that bilateral temperature compensation allows a two-order compensating circuit to achieve three-order compensation, thus acquiring reference voltage of very low temperature coefficient; bilateral temperature compensation of the high and low temperatures is finished by the same circuit, the circuit complexity is greatly reduced, and an implanting manner is simple and reliable.

Description

A kind of band-gap reference circuit of bilateral temperature compensation

Technical field

The present invention relates in ADC, DC-DC circuit the reference voltage source needing to produce extremely low temperature coefficient, the not temperature variant reference voltage source especially in high-speed, high precision circuit,

Background technology

In Modem simulation circuit, the circuit such as D and D/A converter (ADC/DAC), low pressure difference linear voltage regulator (LDO), Voltage-voltage converter, all need a high-precision reference voltage, reference voltage directly affects the performance of above-mentioned mimic channel.For meeting the requirement under varying environment, especially temperature requirement, reference voltage source should have extremely low temperature coefficient.The maximum reference voltage source of current application is band-gap reference, and output voltage is about 1.25V.Its principle is the positive temperature characterisitic of the base-emitter pressure reduction (Δ VBE) utilized under bipolar transistor (BJT) different current density, offset with the negative temperature characteristic of the base emitter voltage VBE of bipolar transistor, produce the voltage reference of first compensation phase, and by the high-order temperature term of high-order temperature compensated elimination VBE, the reference voltage source of lower temperature coefficient can be obtained.

Summary of the invention

The present invention proposes a kind of band-gap reference circuit of bilateral temperature compensation, use BiCMOS technique realizes, the reference circuit that conventional first order compensates improves, increase bilateral temperature-compensation circuit, carry out the bilateral compensation of high/low temperature, eliminate the high-order temperature term of VBE, thus obtain the reference voltage of extremely low temperature coefficient.

Technical scheme of the present invention is as follows:

A band-gap reference circuit for bilateral temperature compensation, comprises first compensation phase reference generating circuit, error amplifier, high/low temperature compensation trsanscondutance amplifier, compensation and divider resistance; Described first compensation phase reference generating circuit produces reference voltage and the positive temperature coefficient (PTC) voltage of first compensation phase; The reference voltage of described first compensation phase produces high voltage and low-voltage through divider resistance dividing potential drop, described high voltage, low-voltage and positive temperature coefficient (PTC) voltage input high/low temperature compensates trsanscondutance amplifier, the output terminal that described high/low temperature compensates trsanscondutance amplifier connects the compensating resistance lower end that reference voltage exports branch road, when positive temperature coefficient (PTC) voltage is higher than high voltage with lower than low-voltage, the output terminal that described high/low temperature compensates trsanscondutance amplifier extracts electric current from outside, and the compensating resistance of reference voltage output branch road produces bucking voltage; Described error amplifier connects first compensation phase reference generating circuit and compensating resistance, carries out clamper to benchmark, provides electric current for reference voltage exports branch road simultaneously.

Its further technical scheme is:

Described first compensation phase reference generating circuit comprises the first transistor, the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the first triode and the second triode; The grid of the first transistor connects bias voltage, and the drain electrode of the first transistor connects supply voltage; First triode is connected with the base stage of the second triode; First resistance is connected between the source electrode of the first transistor and the collector of the first triode, second resistance is connected between the source electrode of the first transistor and the collector of the second triode, 3rd resistance is connected between the emitter of the first triode and the second triode, between the emitter that the 4th resistance is connected to the second triode and ground;

The reverse input end of described error amplifier connects the collector of the first triode, and input end connects the collector of the second triode in the same way, and output terminal is as reference voltage output end;

Described compensation and divider resistance comprise the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance and the 9th resistance of connecting; 5th resistance connects reference voltage output end, the 9th resistance eutral grounding; 6th resistance is connected the base stage of the first triode and the second triode with the mid point of the 7th resistance;

Three input ends that described high/low temperature compensates trsanscondutance amplifier connect the mid point of the 7th resistance and the 8th resistance, the 8th resistance and the mid point of the 9th resistance, the emitter of the second triode respectively; Output terminal connects the mid point of the 5th resistance and the 6th resistance.

And its further technical scheme is:

Described high/low temperature compensates trsanscondutance amplifier and comprises transistor seconds, third transistor, the 4th transistor, the 5th transistor, the 6th transistor, the 7th transistor, the tenth resistance, the 11 resistance, the 3rd triode, the 4th triode and the 5th triode;

Third transistor is connected the positive temperature coefficient (PTC) voltage that described first compensation phase reference generating circuit produces with the grid of the 4th transistor, the grid of transistor seconds connects described high voltage, the grid of the 5th transistor connects described low-voltage, transistor seconds is connected with the drain electrode of the 4th transistor, and third transistor is connected with the drain electrode of the 5th transistor;

The grid of the 6th transistor and the 7th transistor connects bias voltage, the source electrode of the 6th transistor and the 7th transistor connects supply voltage, the drain electrode of the 6th transistor is connected with the source electrode of third transistor with transistor seconds, and the drain electrode of the 7th transistor is connected with the source electrode of the 4th transistor with the 5th transistor;

Tenth resistance is connected between the drain electrode of third transistor and the collector of the 3rd triode, and the 11 resistance is connected between the drain electrode of the 4th transistor and the collector of the 4th triode;

The base stage of the 3rd triode is connected with collector, the base stage of the 4th triode is connected with collector, 4th triode is connected with the base stage of the 5th triode, the collector of the 5th triode as output terminal, the grounded emitter of the 3rd triode, the 4th triode, the 5th triode.

Advantageous Effects of the present invention is:

One, bilateral temperature compensation of the present invention, makes second order compensation circuit can obtain the effect of three rank compensation, thus obtains the reference voltage of extremely low temperature coefficient.

Two, the bilateral temperature compensation of high/low temperature of the present invention is completed by same circuit, and greatly simplifie circuit complexity, implementation is simple and reliable.

Three, circuit of the present invention can obtain the arbitrary value voltage between 1.25V to supply voltage, and output reference voltage has load capacity.

Advantage of the present invention provides in the description of embodiment part below, and part will become obvious from the following description, or be recognized by practice of the present invention.

Accompanying drawing explanation

Fig. 1 is structured flowchart of the present invention.

Fig. 2 is integrated circuit schematic diagram of the present invention.

Fig. 3 is the physical circuit figure that high/low temperature of the present invention compensates trsanscondutance amplifier.

Fig. 4 is compensation principle figure of the present invention.

Fig. 5 is the output voltage variation with temperature curve before and after the present invention compensates.

Embodiment

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described further.

Fig. 1 shows structured flowchart of the present invention.As shown in Figure 1, the present invention includes: first compensation phase reference generating circuit 1, error amplifier 2, high/low temperature compensate trsanscondutance amplifier 3, compensate and divider resistance 4.

Fig. 2 shows integrated circuit schematic diagram of the present invention.As shown in Figure 2, wherein transistor MN1, resistance R1-R4, triode QN1-QN2 form first compensation phase reference generating circuit 1; AMP forms error amplifier 2, for providing clamper and feedback control loop for reference circuit, and provides electric current for output reference voltage; OTA forms high/low temperature and compensates trsanscondutance amplifier 3, for generation of the high-order compensation electric current of high/low temperature; It is compensating resistance that resistance R5-R9 forms compensation with divider resistance 4, R5, and R6-R9 is divider resistance.

The specific works mode of Fig. 2 is as follows: the bandgap voltage reference REF1 and the positive temperature coefficient (PTC) voltage VPTAT that are first produced first compensation phase by first compensation phase reference generating circuit 1.The bandgap voltage reference REF1 of first compensation phase, after resistance R7, R8, R9 dividing potential drop, creates voltage VH, VL of temperature coefficient same with it, and VH>VL.Then voltage VH, VL and positive temperature coefficient (PTC) voltage VPTAT are inputted high/low temperature and compensate trsanscondutance amplifier OTA, the output terminal that high/low temperature compensates trsanscondutance amplifier OTA receives the compensating resistance R5 lower end that reference voltage exports branch road, constitute required high order compensation circuit, the final reference voltage exported is VREF.Triode QN1 and QN2 chooses the very large NPN type pipe of β, makes base current very little, temporarily can ignore its impact.The reference voltage expression formula exported is:

$V_{\mathrm{REF}}=(1+\frac{R_5+R_6}{R_7+R_8+R_9}){\mathrm{REF}}_1+I_1*R_5---\left(1\right)$

First two of formula (1) the right is fixterm, Section 3 I ₁* R ₅for bilateral temperature-compensated voltage.

Below introduce the principle of work of Fig. 2.As shown in Figure 2, voltage VPTAT is the PTAT voltage that single order reference circuit produces, and voltage VH, VL are the dividing potential drop of first compensation phase reference voltage REF1, and relative to voltage VPTAT, the temperature coefficient of voltage VH and VL is very little, can regard the voltage of approximate zero temperature coefficient as.Voltage VH, VL respectively simultaneously and voltage VPTAT compare.When temperature T increases by-50 DEG C to 150 DEG C, voltage VPTAT raises gradually, and experienced by three phases: low-temperature zone: VPTAT<VL; Middle-temperature section: VL<VPTAT<VH; High temperature section: VH<VPTAT.Shown in composition graphs 2, in VL<VPTAT<VH section, the output current I1 that high/low temperature compensates trsanscondutance amplifier OTA is steady state value, and the voltage VR5 that electric current I 1 produces on resistance R5 is also steady state value; In VPTAT<VL and VH<VPTAT section, the output end current I1 that high/low temperature compensates trsanscondutance amplifier OTA increases, and resistance R5 produces the bucking voltage VR5 of low temperature and high temperature section.

Fig. 3 shows a kind of specific embodiment circuit diagram that high/low temperature compensates trsanscondutance amplifier.As shown in Figure 3, its three input ends are respectively VH, VL, VPTAT, and design makes the mutual conductance g of transistor MP2-MP5 _{mn (n=2-5)}identical.From the circuit structure of Fig. 3, at middle-temperature section, i.e. VL<VPTAT<VH section, can obtain with next group current equation:

$\begin{array}{c}{\mathrm{\&Delta;I}}_2=\frac{V_{\mathrm{PTAT}}-V_H}{2}{g}_{m2}\\ {\mathrm{\&Delta;I}}_3=\frac{V_{\mathrm{PTAT}}-V_H}{2}{g}_{m3}\\ {\mathrm{\&Delta;I}}_4=-\frac{V_{\mathrm{PTAT}}{-V}_L}{2}{g}_{m4}\\ {\mathrm{\&Delta;I}}_5=-\frac{V_{\mathrm{PTAT}}-V_L}{2}{g}_{m5}\end{array}---\left(2\right)$

${\mathrm{\&Delta;I}}_1={\mathrm{\&Delta;I}}_2+{\mathrm{\&Delta;I}}_4=\frac{V_{\mathrm{PTAT}}-V_H}{2}{g}_{m2}-\frac{V_{\mathrm{PTAT}}-V_L}{2}{g}_{m4}=-\frac{V_H-V_L}{2}{g}_{m2}---\left(3\right)$

Visible, at middle-temperature section, i.e. VL<VPTAT<VH section, output current variation delta I ₁for fixed value, then output current I ₁=I _{1, DC}+ Δ I ₁also be fixed value.

In low-temperature zone, i.e. VPTAT<VL section, VPTAT<<VH, transistor MP2 turn off, Δ I ₂=0, output current variable quantity is:

${\mathrm{\&Delta;I}}_1={\mathrm{\&Delta;I}}_4=\frac{V_L-V_{\mathrm{PTAT}}}{2}{g}_{m4}---\left(4\right)$

Visible, when temperature is lower, voltage VPTAT is less, Δ I ₁larger, then the bucking voltage VR5 voltage produced is larger, can compensate the reference voltage of low-temperature zone.

In high temperature section, i.e. VPTAT>VH section, VPTAT>>VL, transistor MP5 turn off, Δ I ₅=0, output current variable quantity is:

${\mathrm{\&Delta;I}}_1={\mathrm{\&Delta;I}}_2=\frac{V_{\mathrm{PTAT}}-V_H}{2}{g}_{m2}---\left(5\right)$

Visible, when temperature is higher, voltage VPTAT is larger, Δ I ₁larger, then the bucking voltage VR5 voltage produced is larger, can compensate the reference voltage of high temperature section.

Fig. 4 is the curve synoptic diagram of the output current I1 of voltage VPTAT, VH, VL and compensation trsanscondutance amplifier.Have Fig. 4 known, at middle-temperature section, output current I1 is steady state value substantially; In low-temperature zone and high temperature section, diminishing or becoming large along with voltage VPTAT, output current I1 all becomes large, thus produces larger bucking voltage VR5 on resistance R5, output reference voltage is carried out to the high-order compensation of high/low temperature.

Fig. 5 is the output voltage curve before and after the present invention compensates.As shown in Figure 5, the shape of reference output voltage can be compensated by parabola shaped (REF1) that Open Side Down by the present invention becomes " w " type (VREF), realizes extremely low temperature coefficient, realizes high-precision output reference voltage.

In addition, the error amplifier AMP that the present invention adopts can adopt the amplifier with current output capability, thus the reference voltage exported has load capacity, eliminates the common output buffer without load capacity benchmark (BUFFER).The present invention simultaneously may be used for realizing arbitrarily higher than the high-order compensation reference voltage of first compensation phase benchmark REF1 value.

Above-described is only the preferred embodiment of the present invention, the invention is not restricted to above embodiment.Be appreciated that the oher improvements and changes that those skilled in the art directly derive without departing from the basic idea of the present invention or associate, all should think and be included within protection scope of the present invention.

Claims (3)

1. a band-gap reference circuit for bilateral temperature compensation, is characterized in that, comprises first compensation phase reference generating circuit, error amplifier, high/low temperature compensation trsanscondutance amplifier, compensation and divider resistance; Described first compensation phase reference generating circuit produces reference voltage and the positive temperature coefficient (PTC) voltage of first compensation phase; The reference voltage of described first compensation phase produces high voltage and low-voltage through divider resistance dividing potential drop, described high voltage, low-voltage and positive temperature coefficient (PTC) voltage input high/low temperature compensates trsanscondutance amplifier, the output terminal that described high/low temperature compensates trsanscondutance amplifier connects the compensating resistance lower end that reference voltage exports branch road, when positive temperature coefficient (PTC) voltage is higher than high voltage with lower than low-voltage, the output terminal that described high/low temperature compensates trsanscondutance amplifier extracts electric current from outside, and the compensating resistance of reference voltage output branch road produces bucking voltage; Described error amplifier connects first compensation phase reference generating circuit and compensating resistance, carries out clamper to benchmark, provides electric current for reference voltage exports branch road simultaneously.

2. the band-gap reference circuit of bilateral temperature compensation according to claim 1, it is characterized in that, described first compensation phase reference generating circuit comprises the first transistor, the first resistance, the second resistance, the 3rd resistance, the 4th resistance, the first triode and the second triode; The grid of the first transistor connects bias voltage, and the drain electrode of the first transistor connects supply voltage; First triode is connected with the base stage of the second triode; First resistance is connected between the source electrode of the first transistor and the collector of the first triode, second resistance is connected between the source electrode of the first transistor and the collector of the second triode, 3rd resistance is connected between the emitter of the first triode and the second triode, between the emitter that the 4th resistance is connected to the second triode and ground;

The reverse input end of described error amplifier connects the collector of the first triode, and input end connects the collector of the second triode in the same way, and output terminal is as reference voltage output end;

Described compensation and divider resistance comprise the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance and the 9th resistance of connecting; 5th resistance connects reference voltage output end, the 9th resistance eutral grounding; 6th resistance is connected the base stage of the first triode and the second triode with the mid point of the 7th resistance;

Three input ends that described high/low temperature compensates trsanscondutance amplifier connect the mid point of the 7th resistance and the 8th resistance, the 8th resistance and the mid point of the 9th resistance, the emitter of the second triode respectively; Output terminal connects the mid point of the 5th resistance and the 6th resistance.

3. the band-gap reference circuit of bilateral temperature compensation according to claim 1 or 2, it is characterized in that, described high/low temperature compensates trsanscondutance amplifier and comprises transistor seconds, third transistor, the 4th transistor, the 5th transistor, the 6th transistor, the 7th transistor, the tenth resistance, the 11 resistance, the 3rd triode, the 4th triode and the 5th triode;

Third transistor is connected the positive temperature coefficient (PTC) voltage that described first compensation phase reference generating circuit produces with the grid of the 4th transistor, the grid of transistor seconds connects described high voltage, the grid of the 5th transistor connects described low-voltage, transistor seconds is connected with the drain electrode of the 4th transistor, and third transistor is connected with the drain electrode of the 5th transistor;

The grid of the 6th transistor and the 7th transistor connects bias voltage, the source electrode of the 6th transistor and the 7th transistor connects supply voltage, the drain electrode of the 6th transistor is connected with the source electrode of third transistor with transistor seconds, and the drain electrode of the 7th transistor is connected with the source electrode of the 4th transistor with the 5th transistor;

Tenth resistance is connected between the drain electrode of third transistor and the collector of the 3rd triode, and the 11 resistance is connected between the drain electrode of the 4th transistor and the collector of the 4th triode;

The base stage of the 3rd triode is connected with collector, the base stage of the 4th triode is connected with collector, 4th triode is connected with the base stage of the 5th triode, the collector of the 5th triode as output terminal, the grounded emitter of the 3rd triode, the 4th triode, the 5th triode.