CN202110463U - Variable curvature-compensated band gap voltage reference source - Google Patents

Abstract

The utility model discloses a variable curvature-compensated band gap voltage reference source, including a start circuit, a PTAT current generating circuit and a high-order temperature compensating circuit, wherein the start circuit is used for starting the PTAT current generating circuit; the PTAT current generating circuit is used for generating a PTAT current; the PTAT current is input into the high-order temperature compensating circuit; and the high-order temperature compensating circuit generates the current which has high-order temperature characteristics and is superimposed with the PTAT current; and then a reference voltage is achieved. According to the utility model, high-order temperature compensation is applied to the reference voltage in virtue of a GSC technology, order of compensation varies followed by temperature variation, a conventional first-order compensation mode is adopted at low temperature, a second-order compensation mode is adopted at medium temperature, and a third-order compensation mode is adopted at high temperature. The voltage reference source of the utility model can normally work under a supply voltage down to 1.9V, thereby meeting a requirement of power supply to an integrated circuit by means of a low voltage power supply.

Description

A kind of bandgap reference voltage source of variable curvature compensation

Technical field

The utility model belongs to power technique fields, the design of particularly a kind of voltage-reference (Voltage Reference).

Background technology

Voltage-reference is as the requisite part of integrated circuit, for entire chip provides bias current and a reference voltage is provided.The size of bias current has determined the power consumption situation of entire chip; Simultaneously in chip; A lot of error amplifiers and comparer all are with reference voltage voltage as a reference, and the degree of stability of voltage-reference has determined realization and the quality of performance of the function of chip to a great extent.

The most frequently used voltage-reference is the bandgap reference voltage source based on triode.As shown in Figure 1, because the clamping action of error amplifier, make V _XWith V _Y2 voltage is equal basically, i.e. V _X=V _Y=V _BE2, simultaneously, the electric current that is same as in the two-way also equates then have Because Then electric current is for being proportional to absolute temperature (PTAT, Proporational To Absolute Temperature) electric current, and this electric current becomes the bias current of entire chip through after the mirror image of current mirror.

According to the expression formula of electric current, can draw band gap voltage and be:

Because V _TBe positive temperature coefficient (PTC), simultaneously V _BE2Be negative temperature coefficient, reasonably adjustment factor Size, can realize at a certain temperature that just benchmark is zero with variation of temperature, thereby provide one with the very little reference voltage of temperature variation for entire chip.

Yet the first compensation phase technology has just been adopted in traditional bandgap reference voltage source, however V _BEIn but comprise parameter to the temperature variation high-order, therefore can only accomplish 20 to 100ppm/ ℃ to the temperature coefficient of output voltage, generally be difficult to be lower than 20ppm/ ℃.Simultaneously, now along with development of integrated circuits, supply voltage is more and more lower, requires voltage-reference under low pressure to accomplish and starts and operate as normal.

The utility model content

The purpose of the utility model is in order to solve the problem that existing bandgap reference voltage source exists, to have proposed a kind of bandgap reference voltage source of variable curvature compensation.

The technical scheme of the utility model is: a kind of bandgap reference voltage source of variable curvature compensation comprises start-up circuit, PTAT current generating circuit and high-order temperature compensated circuit; Wherein, Start-up circuit is used to start the PTAT current generating circuit, and the PTAT current generating circuit is used to produce the PTAT electric current, and the PTAT electric current is used to be input to high-order temperature compensated circuit; High-order temperature compensated circuit produces the electric current of high-order temperature characterisitic and superposes with the PTAT electric current, obtains the reference voltage of variable curvature compensation.

Said high-order temperature compensated circuit comprises PMOS pipe, the 2nd PMOS pipe, NMOS pipe, first resistance, second resistance, the 3rd resistance, the 4th resistance, the 5th resistance; First triode, second triode, first electric capacity and amplifier; Wherein, the source electrode and the substrate of PMOS pipe all connect outside power supply, and its grid connects the output terminal of PTAT current generating circuit; Its drain electrode is connected with substrate with the source electrode of NMOS pipe; Grid with the 2nd PMOS pipe is connected with substrate simultaneously, and the grid of NMOS pipe connects the output terminal of amplifier, and drain electrode is connected with the source electrode of the 2nd PMOS pipe; The drain electrode of the 2nd PMOS pipe is connected and is connected to outside power supply behind first resistance; The drain electrode of source electrode and NMOS pipe links to each other with second resistance, one end jointly, and the other end of second resistance is connected with the base stage of an end of the 3rd resistance, the 4th resistance, first triode, second triode respectively, and the other end of the 3rd resistance, the 4th resistance connects the negative sense and the positive input of amplifier respectively; And the collector of first triode, second triode; First triode, second transistor emitter interconnect, and ground connection behind the 5th resistance of connecting, and first electric capacity is connected between the negative input and output terminal of amplifier.

Described PTAT current generating circuit comprises the 3rd PMOS pipe, the 4th PMOS pipe, the 2nd NMOS pipe, the 3rd triode, the 4th triode, the 5th triode, the 6th triode, and the 6th resistance;

Described start-up circuit comprises the 3rd NMOS pipe, the 4th NMOS pipe and the 5th PMOS pipe;

Wherein, The grid leak short circuit of the 4th PMOS pipe; And simultaneously with the grid of the 3rd PMOS pipe, the drain electrode of the 4th triode; And the drain electrode of the 3rd NMOS of start-up circuit pipe, the grid of the PMOS pipe of high-order temperature compensated circuit connects, and the source electrode and the substrate of the 3rd PMOS pipe, the 4th PMOS pipe all connect outside power supply; The drain electrode of the 3rd PMOS pipe is connected with the base stage of the collector of the 3rd triode and base stage, the 4th triode, the grid of the 6th triode, the NMOS pipe of start-up circuit and the grid of the 5th PMOS pipe; The emitter of the 3rd triode is connected with the collector of the 5th triode, the base stage of the 6th triode, and the emitter of the 4th triode is connected the grounded emitter of the 5th triode with the collector of the 6th triode, the base stage of the 5th triode; The emitter of the 6th triode ground connection behind the 6th resistance of connecting, the equal ground connection of drain electrode, source electrode and substrate of the 2nd NMOS pipe;

Wherein, The source electrode and the substrate of the 5th PMOS pipe all connect outside power supply; Grid is connected with the grid of the 4th NMOS pipe and is connected to the PTAT current generating circuit, and the drain electrode of the 5th PMOS pipe is connected with the drain electrode of the 4th NMOS pipe, connects the grid of the 3rd NMOS pipe simultaneously; The drain electrode of the 3rd NMOS pipe is connected to the drain electrode of PTAT current source circuit the 4th PMOS pipe, the source ground of the source electrode of the 3rd NMOS pipe and the 4th NMOS pipe.

The beneficial effect of the utility model is: the GSC technology has been adopted in the bandgap reference voltage source of the variable curvature compensation of the utility model, can high-order compensation be provided for benchmark output, and the substrate current of PMOS pipe is the electric current that and temperature are the high order relation in the high-order temperature compensated circuit; And with a NMOS pipe on the PTAT electric current stack flow through, affact on second resistance and the 5th resistance, realization is high-order temperature compensated to reference voltage; And the order number of compensation changes along with variation of temperature, when low temperature, adopts traditional first compensation phase form; In when temperature; The compensation of realization second order during high temperature, realizes the compensation of three rank.In addition, the voltage-reference of the utility model can satisfy the requirement of integrated circuit to low power supply power supply being low to moderate the normal work of realization under the supply voltage of 1.9V.

Description of drawings

Fig. 1 is existing common band gap voltage-reference synoptic diagram.

Fig. 2 is the bandgap voltage reference structured flowchart of the variable curvature compensation of the utility model.

Fig. 3 is the bandgap voltage reference circuit theory diagrams of the variable curvature compensation of the utility model.

Fig. 4 is that the bandgap voltage reference output of the variable curvature compensation of the utility model realizes circuit theory diagrams.

Fig. 5 concerns synoptic diagram for the output voltage size of the bandgap voltage reference of the utility model embodiment with variation of temperature.

Fig. 6 is the minimum input power supply test figure of the bandgap voltage reference of the utility model embodiment.

Fig. 7 is that the output voltage of bandgap voltage reference of the utility model embodiment is with the situation of change synoptic diagram of input voltage.

Fig. 8 is the PSRR synoptic diagram of the bandgap voltage reference of the utility model embodiment.

Embodiment

Below in conjunction with accompanying drawing and concrete embodiment the utility model is made further description.

As shown in Figure 2, the bandgap reference voltage source of the variable curvature compensation of the utility model comprises start-up circuit; PTAT current generating circuit and high-order temperature compensated circuit, wherein, start-up circuit is used to start the PTAT current generating circuit; The PTAT current generating circuit is used to produce the PTAT electric current; The PTAT electric current is used to be input to high-order temperature compensated circuit, and high-order temperature compensated circuit produces the electric current of high-order temperature characterisitic and superposes with the PTAT electric current, and then obtains the reference voltage of variable curvature compensation.

As shown in Figure 3, high-order temperature compensated circuit comprises PMOS pipe M5, M2, NMOS pipe M1, resistance R 1, R2, R3, R4, R5, triode Q1, Q2; Capacitor C 1 and amplifier OPAMP, wherein, the source electrode of M5 and substrate all meet outside power vd D; Its grid connects the output point of PTAT current source circuit, and its drain electrode is connected with substrate with the source electrode of M1, also is connected with substrate with the grid of M2 simultaneously; The grid of M1 connects the output terminal of amplifier OPAMP, and drain electrode is connected with the source electrode of M2, is connected on the power supply behind the drain series resistance R1 of M2; Its source electrode links to each other with resistance R 2 one ends with the drain electrode of M1 jointly, the other end of resistance R 2 respectively with the end of resistance R 3, R4, the base stage of triode Q1, Q2 connects; The other end of resistance R 3, R4 connects the negative sense and the positive input of amplifier respectively, and the collector of triode Q1, Q2, and triode Q1, Q2 emitter interconnect; And ground connection behind the resistance in series R5, capacitor C 1 are connected between the negative input and output terminal of amplifier OPAMP;

The PTAT current generating circuit comprises PMOS pipe M3, M4, and NMOS manages M6, triode Q3, Q4, Q5, Q6, and resistance R 6.Start-up circuit comprises NMOS pipe MS, MS1, and PMOS manages MS2.

Wherein, the grid leak short circuit of M4, and while and the grid of M3, the drain electrode of Q4; And the drain electrode of the MS of start-up circuit, the grid of the M5 of high-order temperature compensated circuit connects, and the source electrode of M3, M4 and substrate all meet outside power vd D; The drain electrode of M3 is connected with the base stage of the collector of Q3 and base stage, Q4, the grid of M6, the MS1 of start-up circuit and the grid of MS2; The emitter of Q3 is connected with the base stage of the collector of Q5, Q6, and the emitter of Q4 is connected with the base stage of the collector of Q6, Q5, the grounded emitter of Q5; Ground connection behind the emitter resistance in series R6 of Q6, the equal ground connection of the drain electrode of M6, source electrode and substrate;

The source electrode of MS2 and substrate all meet outside power vd D; Grid is connected with the grid of MS1 and is connected to the PTAT current generating circuit; The drain electrode of MS2 is connected with the drain electrode of MS1; Also connect simultaneously the grid of MS, the drain electrode of MS is connected to the drain electrode of PTAT current generating circuit M4, and the source electrode of MS and the source electrode of MS1 be ground connection all.

Be operated in the NPN type triode of forward active area, its collector current and base-emitter voltage V _BESatisfy relational expression:

V _BE(T)=V _G0-mV _T-(the V of η-α) _TLnT formula (1)

Wherein m is a temperature independent amount, and α is the coefficient that collector current depends on temperature, V _G0The band gap voltage of silicon during for OK, η=4-n, n are the dependent coefficient of mobility to temperature, and always between 3 to 4, representative value is 3.45 to the value of η.From formula (1), can find out V _TComprised V among the lnT _BEHigh order amount of nonlinearity to temperature.Therefore, through the high-order term of traditional linear compensation in can not compensation band gap reference voltage.Formula (1) can obtain the temperature differentiate:

$\frac{d{V}_{\mathrm{BE}}\left(T\right)}{\mathrm{DT}}=-(m+\mathrm{\η}-\mathrm{\α})\frac{k}{q}-(\mathrm{\η}-\mathrm{\α})\frac{k}{q}\mathrm{Ln}T$ Formula (2)

Can find out V from formula (2) _BEChange rate (ATCR, Absolute Temperature Change Rate) with absolute temperature is not a fixed value, but a temperature variant value.Generally satisfy η＞α, so ATCR increases along with the increase of temperature.

The band-gap reference output of the utility model realizes that circuit theory diagrams are as shown in Figure 4.Here all resistance all is identical type, and R3 is identical with the R4 resistance.Because the clamping action of operational amplifier OPAMP, triode Q1 has identical current potential with the collector of Q2, therefore flows through R3 and equates with the electric current of R4.GSC triode M2 is operated in weak inversion regime, and its grid and substrate short circuit, therefore, and the source electric current I of M2 _{Source (M2)}Can be divided into two parts, i.e. the body electric current I _{B (M2)}With leakage current I _{D (M2)}The GSC triode here refers to the triode grid and is connected with substrate.

I _{Source (M2)}=I _{D (M2)}+ I _{B (M2)}Formula (3)

In the formula (3): $I_{B\left(M2\right)}=I_S\mathrm{Exp}\frac{V_{\mathrm{GS}\left(M2\right)}}{V_T}=G{T}^{\mathrm{\η}}\mathrm{Exp}(-\frac{V_{G0}}{V_T})\mathrm{Exp}\frac{V_{\mathrm{GS}\left(M2\right)}}{V_T}$ Formula (4)

$I_{D\left(M2\right)}={\mathrm{HT}}^{\mathrm{\η}}\mathrm{Exp}\frac{k_1}{V_T}\mathrm{Exp}\frac{V_{\mathrm{GS}\left(M2\right)}}{n^{\′}{V}_T}$ Formula (5)

Wherein G and H are temperature independent amount, n '=1+G _Js/ C _Ox, C _JsBe depletion region capacitance, C _OxBe gate capacitance, k ₁=-V _G0-V _OFF/ n ' also is a temperature independent constant.Can find out output reference voltage V through Fig. 4 _REFSize be:

V _REF=V _{BE (Q2)}+ (R ₂+ R ₅) * I _PTAT+ (R ₂+ R ₅) * I _{D (M2)}Formula (6)

In the formula (6), I _PTATBe the PTAT electric current, first in the expression formula is traditional first compensation phase of band-gap reference with second, last (R ₂+ R ₅) * I _{D (M2)}Be used for compensating V _BEIn the high order amount of nonlinearity.

Obtain by Kirchhoff's law:

I _PTAT=I _{B (M2)}+ I _{D (M1)}Formula (7)

Triode M1 is biased in the forward active area, its leakage current I _{D (M1)}For:

$I_{D\left(M1\right)}=\frac{{\mathrm{\&beta;}}_{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000060377210000011.png,HDA0000060377210000021.png"\; state="\{\{state\}\}">M</figure-callout>}1}}{2}{(V_{\mathrm{SG}\left(M1\right)}-|V_{\mathrm{THP}}\left|\right)}^2$ Formula (8)

In the formula (8), β _M1=μ _pC _OX(W/L) _M1

In order to simplify derivation, suppose I _PTAT=γ V _T, wherein γ is a temperature independent constant, μ _nAnd μ _oTemperature there is identical order, is divided into following two kinds of situation according to different temperature.

A. when temperature is relatively low, the electric current I in the formula (7) _{B (M2)}Than electric current I _{D (M1)}Very little, thus when temperature is relatively low I _{B (M2)}Can ignore.

If make triode M1 be operated in the edge of saturation region, i.e. V through the working point rationally is set _{SG (M1)}-V _TH=V _{SD (M1)}, like this, can obtain V by formula (7) and formula (8) _{GS (M2)}Expression formula do

$V_{\mathrm{GS}\left(M2\right)}=V_{\mathrm{SD}\left(M1\right)}=\sqrt{\frac{2}{{\mathrm{\&beta;}}_{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000060377210000011.png,HDA0000060377210000021.png"\; state="\{\{state\}\}">M</figure-callout>}1}}\mathrm{\&gamma;}{V}_T}$ Formula (9)

In conjunction with formula (5) and formula (9), the leakage current of M2 does

$I_{D\left(M2\right)}={\mathrm{HT}}^{\mathrm{\&eta;}}\mathrm{Exp}(\frac{k_1}{V_T}+\sqrt{\frac{k_2}{T^{\mathrm{\&eta;}-3}}})$ Formula (10)

K wherein ₂Be a temperature independent constant, formula (10) can get the temperature differentiate

$\frac{d{I}_{D\left(M2\right)}}{\mathrm{DT}}={\mathrm{HT}}^{\mathrm{\&eta;}-1}\mathrm{Exp}(\frac{k_1}{V_T}+\sqrt{\frac{k_2}{T^{\mathrm{\&eta;}-3}}})\&times;\{\mathrm{\&eta;}-\frac{{\mathrm{<figure-callout\; id="1"\; label="Qk"\; filenames="HDA0000060377210000011.png,HDA0000060377210000021.png"\; state="\{\{state\}\}">Qk</figure-callout>}}_1}{\mathrm{KT}}-\frac{1}{2}\sqrt{k_2}(\mathrm{\&eta;}-3){\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="HDA0000060377210000011.png,HDA0000060377210000021.png"\; state="\{\{state\}\}">T</figure-callout>}}^{\frac{1}{2}(3-\mathrm{\&eta;})}\}$ Formula (11)

In the formula (11), I _{D (M2)}TC be on the occasion of, and ATCR increases along with the increase of temperature.In conjunction with formula (2) and formula (6), can obtain the second order compensation of band-gap reference.Under lower temperature, first compensation phase can pass through V _{BE (Q2)}(R ₂+ R ₅) * I _PTATRealize, under medium temperature, V _REFMiddle (the R that increases ₂+ R ₅) * I _{D (M2)}Offset V _{BE (Q2)}In the recruitment of ACTR.

If V _{SG (M1)}-V _TH＜V _{SD (M1)}, formula (7) can be expressed as under relatively low temperature:

$\mathrm{\&gamma;}{V}_T=\frac{{\mathrm{\&beta;}}_{\mathrm{<figure-callout\; id="1"\; label="M"\; filenames="HDA0000060377210000011.png,HDA0000060377210000021.png"\; state="\{\{state\}\}">M</figure-callout>}1}}{2}{[V_{\mathrm{SG}\left(M1\right)}-|V_{\mathrm{THP}}\left|\right]}^2$ Formula (12)

Because β _M1Be negative temperature coefficient, V _{SG (M1)}-| V _THP| can rise along with the increase of temperature, therefore, voltage V _{SD (M1)}Have two kinds of situation, a kind of is steady state value, and another kind is ever-increasing value.

(A1) if voltage V _{SD (M1)}Be steady state value, voltage V _{GS (M2)}It is steady state value.Because k ₃=k ₁+ V _{SD (M1)}/ n ' is provided with k simultaneously ₂=0, then have

$\frac{d{I}_{D\left(M2\right)}}{\mathrm{DT}}={\mathrm{HT}}^{\mathrm{\&eta;}-1}(\mathrm{\&eta;}-\frac{{\mathrm{<figure-callout\; id="1"\; label="Qk"\; filenames="HDA0000060377210000011.png,HDA0000060377210000021.png"\; state="\{\{state\}\}">Qk</figure-callout>}}_1}{\mathrm{KT}})\mathrm{Exp}\left(\frac{k_3}{V_T}\right)$ Formula (13)

Similarly, I _{D (M2)}TC be positive, and ATCR increases along with the increase of temperature.

(A2) if V _{SD (M1)}Rise, then V _{GS (M2)}Also rise, therefore, I _{D (M2)}TC trend similar with top situation.As long as M1 is operated in the saturation region, band-gap reference just can correctly be worked.Condition V _{SG (M1)}-V _TH≤V _{SD (M1)}Only can have influence on and make C is zero temperature.

B. when a high relatively temperature, the I in the formula (7) _{B (M2)}Can compare I _{D (M1)}Big is many, so I _{B (M2)}When high temperature, play a major role.In conjunction with formula (4), V _{GS (M2)}Expression formula do

$V_{\mathrm{GS}\left(M2\right)}=V_T\mathrm{Ln}\frac{\mathrm{\&gamma;}{V}_T}{{\mathrm{GT}}^{\mathrm{\&eta;}}\mathrm{Exp}(-\frac{V_{G0}}{V_T})}$ Formula (14)

Based on formula (5) and formula (14), the leakage current of M2 can be expressed as

$I_{D\left(M2\right)}\&ap;{\mathrm{JT}}^{\frac{1}{n^{\&prime;}}}\mathrm{Exp}\left(\frac{k_4}{V_T}\right)$ Formula (15)

Wherein J is the constant that is independent of temperature, k ₄=-V _OFF/ n '.Formula (15) can obtain the temperature differentiate

$\frac{d{I}_{D\left(M2\right)}}{\mathrm{DT}}=(\frac{J}{n^{\&prime;}}{T}^{\frac{1}{n^{\&prime;}}-1}-\frac{\mathrm{Jq}{k}_4}{k}{T}^{\frac{1}{n^{\&prime;}}-2})\mathrm{Exp}\frac{k_4}{V_T}$ Formula (16)

Because n ' is bigger slightly than 1, and k ₄Be negative value, so I in the formula (16) _{D (M2)}Rate of temperature change be on the occasion of.Yet the value of ATCR reduces along with the increase of temperature, in conjunction with formula (2) and formula (6), output reference voltage V _REFWhen high temperature, can descend.

Can find out, when low temperature, through V _{BE (Q2)}(R ₂+ R ₅) * I _PTATCarry out first compensation phase.In when temperature, TC be just and the ATCR value along with the electric current I of temperature increase _{D (M2)}Be added into V _REFExpression formula in, offset V _{BE (Q2)}In the recruitment of ATCR with temperature, being band-gap reference has increased the second order compensation rate.When higher relatively temperature, TC is for just, but the electric current I that ATCR reduces with temperature _{D (M2)}Be increased to V _REFExpression formula in, therefore, output voltage V _REFWhen high temperature, can descend, this is the three rank compensation of band-gap reference.Do not increase extra circuit structure, only through a particular structural, making the TC of output reference voltage can be 0 under three temperature, and makes the temperature of benchmark output voltage float to reach to minimize.The variable curvature circuit that proposes in the literary composition is through electric current item I _{D (M2)}Realized high-order temperature compensated, I _{D (M2)}The temperature characterisitic that a variation is arranged in whole temperature range.The temperature characterisitic of circuit is as shown in Figure 5.

Owing to increased GSC triode M2, this circuit can be under a low-voltage operate as normal, from Fig. 4, can obtain, minimum output voltage expression formula does

V _{DD_minimum}=V _REF+ V _{GS (M2)}+ V _{OV (IPTAT)}Formula (17)

V wherein _{OV (IPTAT)}For the overdrive voltage of PTAT current source, at I _PTATCurrent source is under the situation of single tube, and its value is typically about 200mV, V _REFBe the reference voltage output valve of the utility model, because M2 is biased in weak anti-type state, V _{GS (M2)}Value is less than V _THN, in addition, the bulk potential of M2 is bigger than source electric potential, because the threshold voltage that influences M2 of bulk effect can reduce relatively.Can obtain among Fig. 6, minimum power source voltage probably is 1.9V.Can find out that this reference voltage source can be at operation at low power supply voltage.

Variation to supply voltage is insensitive more, and the performance of reference voltage is also just good more.As shown in Figure 3, output only has two paths, i.e. path1 among Fig. 4 and path2 from the power supply to the benchmark.Because from the decay of drain-to-source, path2 can weaken the influence of mains fluctuations to output significantly.The method of improving PSRR is that to make the PTAT current source be an ideal current source as much as possible.The M3 of the PTAT current source of the utility model has identical breadth length ratio and bigger channel length is arranged with M4 and M5; Can reduce the channel length modulation effect like this; Simultaneously, because the negative feedback of Q3, Q4, Q5, Q6, C is identical with the current potential of 2 of D; Can improve PSRR, the electric capacity filter action that meets the M6 of method has also improved PSRR to a certain extent in addition.Can see among Fig. 7 that when supply voltage changed in 1.9 to 5V the scope, output voltage had probably only become 0.001V.Can obtain among Fig. 8, when being lower than 1KHz, PSRR when 10KHz, still has the PSRR up to 58.5dB up to 70.5dB.

In the PTAT current source circuit, in order to keep the electric current in the two-way consistent, current-mirror structure has adopted relatively big size, to reduce the influence of Early effect as much as possible, can increase their matching simultaneously.Q3, Q4, Q5, Q6 adopt the method that connects like Fig. 3, form negative feedback loop, and the C point is equated with the current potential that D is ordered.M6 is the electric capacity connected mode, can serve as the dominant pole of loop on the one hand, can serve as filter capacitor on the other hand.Because the current potential that C, D are 2 is identical, the voltage swings above the resistance R 6 do

V _R6=V _BE5-V _BE6=V _TLnM formula (18)

In the formula (18), M is Q6 and the ratio of the number of Q5, and the PTAT size of current does thus

$I_{\mathrm{PTAT}}=I_{R6}=\frac{V_{\mathrm{BE}5}-V_{\mathrm{BE}6}}{R_6}=\frac{V_T\mathrm{Ln}M}{R_6}$ Formula (19)

Here, when start-up circuit starts, because the current potential that A is ordered is relatively low; Then MS2 conducting makes the grid current potential of MS be height, thereby makes the MS conducting; The B point has just been received earth potential, and this has just formed a current path from M4 to MS, has after the electric current among the MS; To following injection current, make circuit break away from zero condition, get into duty.Then, the A current potential of ordering can rise to 2V _BE, make the MS1 conducting, pull down to ground to the grid current potential of MS, thereby close MS, start-up circuit is no longer exerted an influence to the PTAT current source circuit of back, start and accomplish.Accomplish after the startup, than under the condition with higher, though MS1 and MS2 conducting simultaneously, because the breadth length ratio of MS2 is very little, the electric current that therefore flows through is also very little at supply voltage.

The utility model can be applicable in the chip of BiCMOS and CDMOS technology, for entire chip is carried bias current and reference voltage.Owing to adopted the variable curvature compensation, make the benchmark output voltage have very high stability, because circuit satisfies the requirement of low voltage operating, make the utility model that accommodation very widely arranged simultaneously.

Those of ordinary skill in the art will appreciate that embodiment described here is in order to help the principle of reader understanding's the utility model, should to be understood that the protection domain of the utility model is not limited to such special statement and embodiment.Those of ordinary skill in the art can make various other various concrete distortion and combinations that do not break away from the utility model essence according to disclosed these teachings of the utility model, and these distortion and combination are still in the protection domain of the utility model.

Claims (4)

1. the bandgap reference voltage source of a variable curvature compensation comprises start-up circuit, the PTAT current generating circuit; High-order temperature compensated circuit, wherein, start-up circuit is used to start the PTAT current generating circuit; The PTAT current generating circuit is used to produce the PTAT electric current; The PTAT electric current is used to be input to high-order temperature compensated circuit, and high-order temperature compensated circuit produces the electric current of high-order temperature characterisitic and superposes with the PTAT electric current, and then obtains the reference voltage of variable curvature compensation.

2. the bandgap reference voltage source of variable curvature compensation according to claim 1; It is characterized in that said high-order temperature compensated circuit comprises PMOS pipe, the 2nd PMOS pipe, NMOS pipe, first resistance, second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, first triode, second triode, first electric capacity and amplifier, wherein; The source electrode and the substrate of the one PMOS pipe all connect outside power supply; Its grid connects the output terminal of PTAT current generating circuit, and its drain electrode is connected with substrate with the source electrode of NMOS pipe, and the grid with the 2nd PMOS pipe is connected with substrate simultaneously; The grid of the one NMOS pipe connects the output terminal of amplifier; Drain electrode is connected with the source electrode of the 2nd PMOS pipe, and the drain electrode of the 2nd PMOS pipe is connected and is connected to the power supply of outside behind first resistance, and source electrode links to each other with second resistance, one end with the drain electrode that a NMOS manages jointly; The other end of second resistance is connected with the base stage of an end of the 3rd resistance, the 4th resistance, first triode, second triode respectively; The other end of the 3rd resistance, the 4th resistance is the negative sense and the positive input of concatenation operation amplifier respectively, and the collector of first triode, second triode, and first triode, second transistor emitter interconnect; And ground connection behind the 5th resistance of connecting, first electric capacity are connected between the negative input and output terminal of amplifier.

3. the bandgap reference voltage source of variable curvature compensation according to claim 2; It is characterized in that; Described PTAT current generating circuit; Comprise the 3rd PMOS pipe, the 4th PMOS pipe, the 2nd NMOS pipe, the 3rd triode, the 4th triode, the 5th triode, the 6th triode, and the 6th resistance;

Described start-up circuit comprises the 3rd NMOS pipe, the 4th NMOS pipe and the 5th PMOS pipe;

Wherein, The grid leak short circuit of the 4th PMOS pipe; And simultaneously with the grid of the 3rd PMOS pipe, the drain electrode of the 4th triode; And the drain electrode of the 3rd NMOS of start-up circuit pipe, the grid of the PMOS pipe of high-order temperature compensated circuit connects, and the source electrode and the substrate of the 3rd PMOS pipe, the 4th PMOS pipe all connect outside power supply; The drain electrode of the 3rd PMOS pipe is connected with the base stage of the collector of the 3rd triode and base stage, the 4th triode, the grid of the 6th triode, the NMOS pipe of start-up circuit and the grid of the 5th PMOS pipe; The emitter of the 3rd triode is connected with the collector of the 5th triode, the base stage of the 6th triode, and the emitter of the 4th triode is connected the grounded emitter of the 5th triode with the collector of the 6th triode, the base stage of the 5th triode; The emitter of the 6th triode ground connection behind the 6th resistance of connecting, the equal ground connection of drain electrode, source electrode and substrate of the 2nd NMOS pipe;

Wherein, The source electrode and the substrate of the 5th PMOS pipe all connect outside power supply; Grid is connected with the grid of the 4th NMOS pipe and is connected to the PTAT current generating circuit, and the drain electrode of the 5th PMOS pipe is connected with the drain electrode of the 4th NMOS pipe, connects the grid of the 3rd NMOS pipe simultaneously; The drain electrode of the 3rd NMOS pipe is connected to the drain electrode of PTAT current source circuit the 4th PMOS pipe, the source ground of the source electrode of the 3rd NMOS pipe and the 4th NMOS pipe.

4. the bandgap reference voltage source of variable curvature compensation according to claim 3 is characterized in that, described PMOS pipe, the 3rd PMOS pipe and the 4th PMOS pipe have identical breadth length ratio.

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