CN101833352A - High-order compensation band gap reference voltage source - Google Patents

Abstract

The invention discloses a high-order compensation band gap reference voltage source comprising an output branch for outputting a reference voltage. The high-order compensation band gap reference voltage source is characterized by also comprising an earthed resistance structure playing a role of a resistor and a high-order compensation circuit, wherein the high-order compensation circuit and the output branch are connected in parallel and are respectively connected to a current input end of the earthed resistor structure; a current output end of the earthed resistor structure is earthed; the high-order compensation circuit is used for inputting current to the current input end of the earthed resistor when the current in the output branch is reduced caused by the temperature rise; the structure is applicable for various processes without depending on an accurate process and has wide application range; and besides, the circuit area cannot be substantially increased. In addition, the temperature coefficient of the high-order compensation band gap reference voltage source is far superior to that of the traditional high-order compensation band gap reference voltage source.

Description

High-order compensation band gap reference voltage source

Technical field

The present invention relates to integrated circuit fields, relate in particular to high-order compensation band gap reference voltage source.

Background technology

Bandgap voltage reference is meant the voltage source that can play reference role in circuit, needs high precision, and the reference voltage of its output will few as far as possible variation with the ambient temperature variation.Reference voltage source is used very extensive, in data converter (comprising analog to digital converter and digital to analog converter), sensor, power source management controller and various high-acruracy survey instrument.Its precision directly has influence on the performance of each module of circuit, has important effect.

For bandgap voltage reference, an important indicator investigating performance is temperature coefficient (TC, Temperature Coefficient), and the unit of temperature coefficient is PPM/ ℃, and the expression formula of temperature coefficient is:

$\mathrm{TC}=\left[\frac{V_{\mathrm{MAX}}-V_{\mathrm{MIN}}}{V_{\mathrm{reference}}\×(\mathrm{TMAX}-\mathrm{TMIN})}\right]\×{10}^6$

Temperature coefficient is used to show in the limiting temperature scope, the magnitude range of bandgap voltage reference reference voltage.

The realization principle of band-gap reference is mainly based on following 2 points:

First point: the V of triode _BE(base---launch site voltage) has negative temperature coefficient.V _BEHas following expression (list of references: Y.P.Tsividis " Accurate Analysis of Temperature Effectsin/c-l/BE Characteristics with Application to Bandgap Reference Sources ", IEEEJournal of Solid-State Circuits, vol.SC-15.no.6, pp.1076-1084, Dec.1980.)

$V_{\mathrm{BE}}\left(T\right)=V_{\mathrm{Go}}+(V_{\mathrm{BE}0}-V_{G0})\left(\frac{T}{T_0}\right)-\mathrm{\η}{V}_T\ln \left(\frac{T}{T_0}\right)+V_T\ln \frac{I_C}{I_C\left(T0\right)}$

In the expression formula, V _GoReference voltage during for absolute zero.V _BE0Representing reference temperature is T ₀The time emitter junction voltage.The parameter that η is relevant with technology is generally 2.When technology was determined, η can be considered as determining.V _TBe thermal voltage, it is directly proportional with temperature, and (300K) at normal temperatures, its value is about 25.85mv.From expression formula as can be seen, in certain accuracy rating, if ignore higher order term.V then _BE(T) can think that constant temperature coefficient is arranged.

Second point: when the collector current of two triodes is unequal, the V of the two _BEDifference Δ V _BEHas positive temperature coefficient.When collector current suitably little, when base mudulation effect, big injection effect and base resistance can be ignored, Δ V _BEExpression formula is:

${\mathrm{\ΔV}}_{\mathrm{BE}}=V_T\ln \frac{I_{C1}}{I_S}-V_T\ln \frac{I_{C2}}{I_S}=V_T\ln \frac{I_{C1}}{I_{C2}}$

Because V _THave positive temperature coefficient, and its value is almost constant when temperature variation, so Δ V _BEHave positive temperature coefficient, and can think that its temperature coefficient does not vary with temperature and changes.The V that will have like this, negative temperature coefficient _BEWith Δ V with positive temperature coefficient (PTC) _BEBy the proper ratio addition, then can obtain temperature independent reference voltage.Expression formula is Vref=V _BE+ k Δ V _BEThe principle of Here it is common first compensation phase band-gap reference circuit

Based on the typical circuit of the single order band-gap reference of this principle as shown in Figure 1. at first, the negative feedback by operational amplifier 10 constitutes has guaranteed that first node X has identical magnitude of voltage with Section Point Y.The voltage difference at such first resistance R 1 two ends is:

${\mathrm{\ΔV}}_{\mathrm{BE}}=V_{\mathrm{BE}}\left(Q1\right)-V_{\mathrm{BE}}\left(Q2\right)=V_T\ln \frac{I_C\left(Q1\right)}{I_C\left(Q2\right)}$

Equate owing to flow through the electric current of the first triode Q1 and the second triode Q2 collector, if the second triode Q2 is by N the first triode Q1 parallel connection, then

Δ V _BE=V _TLn N so flow through the electric current of the first short R1 of rent is:

Promptly produced with temperature coefficient be positive electric current.Because PMOS pipe P1, the 2nd PMOS pipe P2 and the 3rd PMOS pipe P3 flow through electric current much at one, so the reference voltage of output can be expressed as:

In this formula, first has positive temperature coefficient (PTC), and second has negative temperature coefficient.Suitable choosing

Value, then the two can be offset to greatest extent, obtain not temperature variant substantially reference voltage.

Yet the band-gap reference of this first compensation phase can not have good precision.Because V from the above analysis, _BENegative temperature coefficient do not fix, along with variation of temperature, variation to a certain degree also can take place in its temperature coefficient.And by Δ V _BEThe positive temperature coefficient (PTC) that produces but can be thought and not vary with temperature (suitable hour of electric current can be ignored base mudulation effect and big injection effect).Like this, only may to have a temperature coefficient be zero temperature spot to Vref.Be higher than this temperature spot, Vref will raise and descend with temperature.Such its temperature coefficient of first compensation phase band-gap reference is difficult to accomplish 20ppm/ ℃; So such circuit structure can't satisfy the occasion of high-precision requirement, just produced the demand of high-order compensation thus.

Several frequently seen high-order compensation scheme has the (reference: Philip K.T.Mok of resistance ratios method at present, KaNang Leung, " Design considerations of recent Advanced Low-voltageLow-temperature-coefficient CMOS Bandgap Voltage Reference "), (the reference: Piero Malcovati of nonlinear compensation method, Franco Maloberti, Fellow, IEEE, Carlo Fiocchi, and MarcelloPruzzi, " Curvature-Compensated BiCMOS Bandgap with1-V Supply Voltage " IEEEJOURNAL OF SOLID-STATE CIRCUITS, VOL.36, NO.7, JULY 2001) and (reference: Ming-Dou Ker of double-current penalty method, Jung-Sheng Chen, and Ching-Yun Chu, " NewCurvature-Compensation Technique for CMOS Bandgap Reference with Sub-1-VOperation "), yet voltage structure in these compensation schemes or the accurate technology of needs, perhaps area is excessive, and very big limitation is all arranged.

A kind of high-order compensation band gap reference voltage source circuit (reference: WAN Yuanjiao that Li Zhi group etc. propose, L IU Guizhi, L I Zhiqun; " A New Piecewise Higher2Order Compensation BandgapVoltage Reference " the microelectronics journal; the 38th the 4th phase of volume) adopted a kind of by compensating resistance paralleling switch pipe being carried out the structure of high-order compensation; this structure has been added the paralleling switch pipe; however there is following deficiency in sort circuit; the paralleling switch pipe needs lower threshold voltage, so the technology that is suitable for is few; The threshold voltage of paralleling switch pipe need obtain accurately determining in addition, otherwise can't bring correct compensation effect, even can make circuit performance become poorer, makes that this reference voltage source scope of application is very little.

Summary of the invention

Goal of the invention of the present invention is to provide high-order compensation band gap reference voltage source, with limitation such as overcome existing high-order compensation band gap reference voltage source technological requirement height, applicable craft is few, the scope of application is little and area is excessive.

A kind of high-order compensation band gap reference voltage source provided by the invention is added with stake resistance structure and high-order compensation circuit, stake resistance structure and the parallel connection of high-order compensation circuit, wherein the current input terminal of stake resistance structure is connected to output branch road and high-order compensation circuit, and its current output terminal ground connection, the electric current of output branch road and high-order compensation circuit is by stake resistance structure inflow place, the high-order compensation circuit is used for rising in temperature and improves temperature coefficient to stake resistance structure input offset current to improve reference voltage when causing exporting the branch road electric current and reducing to cause reference voltage to reduce, this structure need not to rely on accurate technology, be suitable for a variety of technologies, have wide range of applications, can not increase considerably circuit area in addition, having overcome existing high-order compensation band gap reference voltage source needs accurate technology to cooperate, the circuit area increase greatly and only is fit to various limitations such as special process.The temperature coefficient of high-order compensation band gap reference voltage source provided by the invention is far superior to the temperature coefficient of existing high-order compensation band gap reference voltage source in addition.

The stake resistance structure of reference voltage source provided by the invention can be made up of resistance and/or metal-oxide-semiconductor.

The high-order compensation circuit of reference voltage source provided by the invention can comprise one or more high-order compensation branch roads, described high-order compensation props up route compensating resistance structure and the MOS structure is formed by connecting, wherein the current input terminal of compensating resistance structure is connected in the State Control end of MOS structure, the current input terminal of compensating circuit structure in the current output terminal ground connection of compensating resistance structure or other high-order compensation branch road; And the current output terminal of MOS structure is connected to the current input terminal of stake resistance structure, can obtain suitable compensation precision by the number that increases or reduce the high-order compensation branch road, can also be applicable to the application of low reference voltage and low input, the compensating resistance structure also can be made up of resistance and/or metal-oxide-semiconductor.

Description of drawings

Fig. 1 is the electrical block diagram of existing single order bandgap voltage reference;

The electrical block diagram of the high-order compensation band gap reference voltage source that Fig. 2 provides for the embodiment of the invention;

Fig. 3 is the reference voltage of existing voltage source and the graph of relation of temperature;

Fig. 4 is the reference voltage of voltage source in the embodiment of the invention and the graph of relation of temperature;

Embodiment

As shown in Figure 2, the structure of present embodiment is on traditional first compensation phase band-gap reference circuit basis, be added with stake resistance R3, the 3rd triode Q3 is passed through stake resistance R3 ground connection, and be added with high-order compensation circuit 31, it comprises two high-order compensation branch roads, one of them route the 5th PMOS pipe P5, the one NMOS pipe N1 and the first compensating resistance R4 constitute, another route the 6th PMOS manages P6, the 2nd NMOS pipe N2 and the second compensating resistance R5 constitute, wherein the current input terminal E of the first compensating resistance R4 is connected to the grid (i.e. the State Control end of the MOS structure of the 5th PMOS pipe P5 and NMOS pipe N1 formation) of NMOS pipe N1, its current output terminal is connected to the current input terminal D of the second compensating resistance R5, the current input terminal D of the second compensating resistance R5 is connected to the grid (i.e. the State Control end of the MOS structure of the 6th PMOS pipe P6 and the 2nd NMOS pipe N2 formation) of the 2nd NMOS pipe N2, its current output terminal ground connection, the drain electrode (being the current output terminal of MOS structure in each high-order compensation branch road) of the one NMOS pipe N1 and the 2nd NMOS pipe N2 all is connected to the current input terminal F of stake resistance R3, the current output terminal ground connection of stake resistance R3.In the present embodiment, the first compensating resistance R4 and the second compensating resistance R5 be electric resistance structure by way of compensation, actual structure that metal-oxide-semiconductor structure or metal-oxide-semiconductor and resistance the mixes electric resistance structure by way of compensation that also can adopt, in the present embodiment, stake resistance R3 is as the stake resistance structure, and the actual structure of metal-oxide-semiconductor structure or metal-oxide-semiconductor and resistance mixing that also can adopt is as the stake resistance structure.High-order compensation circuit 31 will begin at the temperature spot of certain setting the reference voltage of output is compensated, and will reach good compensation effect by twice compensation, simultaneously, if precision needs further to improve, can continue to add similar high-order compensation circuit.

Consider V _BETemperature characterisitic as follows:

$V_{\mathrm{BE}}\left(T\right)=V_{\mathrm{Go}}+(V_{\mathrm{BE}0}-V_{G0})\left(\frac{T}{T_0}\right)-\mathrm{\η}{V}_T\ln \left(\frac{T}{T_0}\right)+V_T\ln \frac{I_C}{I_C\left(T0\right)}$

Then analyze easily, it is at close T ₀The district can think that temperature coefficient is constant.And, depart from T along with the rising of temperature ₀Far away more, V _BEWith speeding up that temperature rises and descends.

We obtain following compensation thinking, and at low-temperature space, because first compensation phase is respond well, reference voltage output has good temperature characterisitic.So needn't be compensated, in the high-temperature region, V _BEWith speeding up that temperature rises and descends, need to introduce high-order compensation this moment.

Before the beginning high-order compensation, it is as follows that we obtain reference voltage:

By rationally choosing second resistance R 2, stake resistance R3, the value of first resistance R 1, making Vref is zero to the derivative of temperature at certain temperature value of low-temperature space.This temperature spot is made as T1, at this moment V _BEDerivative expression formula to temperature is:

${\frac{{\&PartialD;V}_{\mathrm{BE}}}{\&PartialD;T}|}_{T=\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="HSA00000102816200031.png"\; state="\{\{state\}\}">T</figure-callout>}0}=\frac{V_{\mathrm{BE}0}-V_{G0}}{T_0}-(\mathrm{\&eta;}-1)\frac{k}{q}$

Thus, the expression formula of positive temperature coefficient (PTC) item is:

$V_T\left(\ln N\right)\frac{R2+R3}{R1}=V_{\mathrm{BE}0}-\frac{V_{\mathrm{BE}0}-V_{G0}}{T_0}T+(\mathrm{\&eta;}-1)\frac{k}{q}(T-T_0)$

Behind T, Vref is about decline through a temperature section:

${\mathrm{\&Delta;V}}_{\mathrm{BE}}=V_{\mathrm{<figure-callout\; id="0"\; label="G"\; filenames="HSA00000102816200031.png"\; state="\{\{state\}\}">G</figure-callout>}0}+\frac{V_{\mathrm{BE}0}-V_{G0}}{T_0}T-(\mathrm{\&eta;}-1)\frac{\mathrm{kT}}{q}\mathrm{<figure-callout\; id="0"\; label="ln\; T\; T"\; filenames="HSA00000102816200031.png"\; state="\{\{state\}\}">ln</figure-callout>}\frac{T}{T_{}}\frac{{}_0}{}+[-V_{G0}-\frac{V_{\mathrm{BE}0}-V_{G0}}{T_0}T+(\mathrm{\&eta;}-1)\frac{k}{q}(T-T_0)]=(\mathrm{\&eta;}-1)\frac{k}{q}[-T\mathrm{<figure-callout\; id="0"\; label="ln\; T\; T"\; filenames="HSA00000102816200031.png"\; state="\{\{state\}\}">ln</figure-callout>}\frac{T}{T_{}}\frac{{}_0}{}+T-T_0]$

If Δ T=T-T ₀, then

If get η=1.7, T0=270k, Δ T are 50k, then Δ V _BEBe about 0.26mv.

In the interval of this Δ T, we compensate by NMOS pipe N1, the compensation process of the one NMOS pipe N1 is: before the E point voltage did not reach the threshold voltage of NMOS pipe N1, NMOS pipe N1 worked in subthreshold region, and its drain current can be expressed with following formula:

Wherein ξ＞1 is an imperfect factor, V _T=kT/q.

Drain current and V as can be seen _GSBe exponential relationship, generally speaking, at room temperature, I if desired _DThe order of magnitude that descends, V _GSNeed decline 80mv.Along with the rising of temperature, when the E point voltage was elevated to NMOS pipe N1 threshold voltage, NMOS pipe N1 entered the saturation region.In subthreshold region and saturation region, inculcate the control that the electric current that compensates to stake resistance R3 is subjected to NMOS pipe N1 fully.

Further rising along with temperature, because the 5th PMOS pipe P5 electric current restriction, the one NMOS pipe N1 pipe enters linear zone, the electric current that offers stake resistance R3 this moment no longer is subjected to NMOS pipe N1 management and control system and is subjected to the 5th PMOS to manage the control of P5 pipe, after just NMOS pipe N1 entered linear zone, inculcating the electric current that compensates to stake resistance R3 was the PTAT electric current.If the temperature when the 5th PMOS pipe P5 enters linear zone is T ₁T is supposed in convenient explanation ₁-T ₀=50k, if not compensation of circuit, V _RefWith decline 0.23mv, can be controlled at T in view of the above ₁Constantly, compensating the voltage that brings should be also at 0.23mv.Manage the size of P3 and the size of stake resistance R3 by choosing the 3rd PMOS suitably, can determine this offset easily.Like this, compensating action has been arranged after, be T in temperature ₀And T ₁The time output reference voltage V _RefEquate.At T ₀And T ₁Certain point also certainly exist one to make output reference be zero temperature spot to the derivative of temperature.

A compensation by so has just guaranteed at T ₀To T ₁Temperature range in, V _RefFluctuation in a controlled very little scope.

When temperature greater than T ₁After, the electric current that flows through stake resistance R3 is the PTAT electric current, like this output reference voltage V _RefTo descend with the trend before the approximate compensation.But follow the rising of temperature this moment, and the 2nd NMOS pipe N2 has entered subthreshold region, with the first time compensation process identical, the 2nd NMOS pipe N2 successively experiences subthreshold region, saturation region and linear zone are stopped V _RefDowntrending, and the T that is setting ₂Constantly, make output reference voltage and T ₀And T ₁Equate, like this, at T ₁And T ₂Also having one in the interval, to make output reference be zero temperature spot to the derivative of temperature.

So, make output reference voltage V by twice compensation _RefIn very big temperature range, its fluctuating range is very little, has reached very low temperature coefficient.

What deserves to be explained is, can introduce three times even the more compensation of high order, make V with same structure _RefPrecision higher.

For the circuit of low output reference voltage and low input, this method is suitable equally in addition.

Carry out emulation by ASMC0.35um BICMOS technology, before compensation, the waveform that obtains output reference voltage as shown in Figure 3, in the scope of-40～125oC, the output reference voltage fluctuation is-2.1mv, corresponding temperature coefficient

After using compensation method provided by the invention, the waveform that obtains output reference as shown in Figure 4, in the scope of-40～125oC, the output reference voltage fluctuation is 188.8uV, corresponding temperature coefficient is: As can be seen, by high-order compensation, the temperature coefficient of the bandgap voltage reference that present embodiment provides has descended about 11 times, has remarkable effect.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims (5)

1. high-order compensation band gap reference voltage source, comprise the output branch road that is used for output reference voltage, it is characterized in that, also comprise the stake resistance structure and the high-order compensation circuit that are used to serve as the resistance effect, described high-order compensation circuit and the parallel connection of output branch road, and all be connected to the current input terminal of stake resistance structure, the current output terminal ground connection of stake resistance structure, and

Described high-order compensation circuit is used for raising when causing exporting the branch road electric current and reducing to the current input terminal input current of stake resistance in temperature.

2. reference voltage source as claimed in claim 1, it is characterized in that, described high-order compensation circuit comprises one or more high-order compensation branch roads, described high-order compensation props up route compensating resistance structure and metals-oxides-semiconductor structure is formed by connecting, wherein the current input terminal of compensating resistance structure is connected in the State Control end of metals-oxides-semiconductor structure, the current input terminal of compensating circuit structure in the current output terminal ground connection of compensating resistance structure or other high-order compensation branch road; And the current output terminal of metals-oxides-semiconductor structure is connected to the current input terminal of stake resistance structure.

3. reference voltage source as claimed in claim 2 is characterized in that, described compensating resistance structure is made up of resistance and/or Metal-oxide-semicondutor pipe.

4. reference voltage source as claimed in claim 2, it is characterized in that, described metals-oxides-semiconductor structure comprises N type Metal-oxide-semicondutor pipe and P type Metal-oxide-semicondutor pipe, N type Metal-oxide-semicondutor pipe and the series connection of P type Metal-oxide-semicondutor pipe; Wherein

The grid of N type Metal-oxide-semicondutor pipe is connected to the current input terminal of compensating resistance structure as the State Control end; And the drain electrode of N type Metal-oxide-semicondutor pipe is connected to the current input terminal of stake resistance structure.

5. reference voltage source as claimed in claim 1 is characterized in that, described stake resistance structure is made up of resistance or Metal-oxide-semicondutor pipe pipe.

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