CN100524147C - Non-linear compensation circuit and bandgap reference circuit using same - Google Patents

Abstract

The invention relates to a nonlinear compensating circuit and the band-gap reference circuit thereof, able to compensate nonlinear effect of voltage reference, where the voltage reference is converted into temperature-irrelated current, the temperature-irrelated current is mirrored by current mirror, and thus the voltage reference is biased by BJT; besides, two resistors are used to estimate nonlinear voltage to feed the nonlinear voltage back to the voltage reference.

Description

Non-linear compensation circuit and the bandgap reference circuit that uses it

Technical field

The present invention relates to a kind of non-linear compensation circuit and the bandgap reference circuit that uses it, and be particularly related to a kind of non-linear compensation circuit and the bandgap reference circuit that uses it that increases the accuracy of band gap reference voltage.

Background technology

Digital analog converter (DAC), analog-digital converter (ADC) or voltage stabilizer (regulator) can need at least a fixing and stable reference voltage.When being preferably in each power initiation, this reference voltage can stably regenerate.Desirable reference voltage even otherwise be subjected to process variations, the variation of operating temperature is with the influence of variation of power supply etc.

Bandgap reference circuit (bandgap reference circuit) can be used for providing reference voltage.Therefore, in many electronic systems, bandgap reference circuit is played an important role, because the degree of stability and the degree of accuracy of its meeting decision systems integral body.

Fig. 1 shows a kind of circuit diagram of well know bandgap reference circuit.As shown in Figure 1, this well know bandgap reference circuit 100 comprises: the current mirror of being made up of MOS (metal-oxide-semiconductor) transistor M101～M103, amplifier OP101～OP103, resistance R 101, R102, R103A and R103B, and two BJT (bipolar junction transistor) transistor B101～B102.The annexation of each element can be understood by Fig. 1.Resistance R 103A equates with the resistance value of R103B.

Reference voltage V _BG1Can be expressed as follows:

V _BG1＝0.5*(V _NTC1+V _PTC1)＝0.5*(V _BE1A+V _PTC1)

＝0.5*(V _BE1A+K1*V _T) (1)

V _PTC1＝I _PTAT1*R102＝(△V _BE/R101)*R102 (2)

△V _BE＝V _T*1n(n) (3)

V _TRepresent thermal voltage (its value is for KT/q, K be Boltzmann's constant (Boltzmann ' sconstant=1.28 x 10 ^-23Joules/Kelvin), T is an absolute temperature, q=1.602 x 10 ^-29Coulomb), K1 is a constant, V _BE1ARepresent the base-emitter voltage of BJT transistor B101, V _NTC1Represent negative temperature (negative temperature coefficient) voltage, V _PTC1Represent positive temperature (PTAT, proportional to absolute temperature) voltage, I _PTAT1Be positive temperature current, n then is the size ratio of transistor B102 to transistor B101.

The transistorized base-emitter voltage of BJT V _BECan be expressed as follows:

V _BE＝V _G0-(V _G0-V _BE0)*T/T ₀-(η-α)*V _Tln(T/T ₀) (4)

In equation (4), T ₀Represent reference temperature, T represents operating temperature, V _BE0Representative is at reference temperature T ₀The base-emitter voltage of following gained, V _G0Silicon bandgap voltage during for absolute temperature 0, η are BJT transistor arrangement coefficient (its value are between 2～6), and factor alpha then depends on the type of BJT transistor biasing electric current.When bias current is positive temperature current, α=1; When bias current is temperature independent electric current, α=0.

Because transistor B101 and B102 are biased in the PTAT electric current, so its α=1.So base-emitter voltage V of transistor B101 and B102 _BE1AWith V _BE1BCan be expressed as:

V _BE1A＝V _G0-(V _G0-V _BE0)*T/T ₀-(η-1)*V _Tln(T/T ₀) (5)

V _BE1B＝V _G0-(V _G0-V _BE0)*T/T ₀-(η-1)*V _Tln(T/T ₀) (6)

Equation (2)～(6) substitution equation (1) can be obtained:

${\mathrm{<figure-callout\; id="1"\; label="V\; BG"\; filenames="C200610076590E00181.png,C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BG}}=\frac{1}{2}\&times;\{[V_{\mathrm{BG}0}-(V_{\mathrm{BG}0}-V_{\mathrm{BE}0})\frac{T}{T_0}-(\mathrm{\&eta;}-1)V_T\ln \frac{T}{T_0}]+[\frac{R102}{R101}\&CenterDot;V_T\&CenterDot;\ln \left(n\right)]\}$

(7)

In equation (7), as make K2=R102/R101*ln (n), then K2*V _TCan be used to compensate V _BEIn linear term.(η-1) * V _TLn (T/T ₀) (V in other words, _TLn (T/T ₀)) then be V _BEIn nonlinear terms.Therefore, reference voltage V _BG1Compensating effect limited, its nonlinear effect still exists.

Fig. 2 demonstrates the compensation concept map of this well know bandgap reference circuit.Fig. 2 demonstrates reference voltage V _BGBe by K2*V _T(positive temperature correlation) and V _BEThe addition of (negative temperature is relevant) forms.Yet, in this well know bandgap reference circuit, at V _BEThe tool nonlinear effect.As compensating V well _BENonlinear effect, will make that in operating temperature range the performance plot of reference voltage can present curve (imperfect) phenomenon, as shown in Figure 3.

Fig. 3 demonstrates desirable reference voltage V _BGShould in operating temperature range, keep stablely, approximate 1.205V.And desirable V _BEAlso should present the good linear effect.But actual V _BEThen present nonlinear effect.Therefore, the V of tool nonlinear effect _BEAdd linear K2*V _TThe reference voltage that is caused also can present nonlinear effect.Thus, will make actual reference voltage in opereating specification, have sizable difference value.

Fig. 4 show known technology in operating temperature between-40 ℃～125 ℃, different power vd D (under the 10.V～1.5V), measured reference voltage V _GB-temperature profile figure.Wherein, curve A 1～E1 represents the V under the situation of VDD=1.5V, VDD=1.4V, VDD=1.3V, VDD=1.2V and VDD=1.1V respectively _GBThe change curve.

As seen from Figure 4, the reference voltage of known technology gained still has sizable change value, and this is because the nonlinear terms of known technology in can't compensate for reference voltage.

Therefore, need that a kind of to obtain reference voltage by the compensating non-linear item stable and change less bandgap reference circuit.

Summary of the invention

The purpose of this invention is to provide a kind of non-linear compensation circuit, it is applicable to the existing bandgap reference circuit of major part.

Another object of the present invention provides a kind of non-linear compensation circuit and the bandgap reference circuit that uses it, and non-linear compensation circuit can increase the accuracy of reference voltage.

Another purpose of the present invention provides a kind of non-linear compensation circuit and the bandgap reference circuit that uses it, and the circuit cost of this non-linear compensation circuit is not high, so but widespread use.

For reaching above-mentioned purpose, embodiments of the invention provide a kind of bandgap reference circuit, comprising: positive temperature current mirror produces positive temperature current and non-linear current; The 3rd resistance is connected between described positive temperature current mirror and the described transistor seconds; Be biased in first and second BJT transistor of described positive temperature current; Amplify and bleeder circuit, feedback is in the base-emitter voltage of described the first transistor, positive temperature voltage and non-linear voltage and output reference voltage; And non-linear compensation circuit, the described reference voltage that utilizes described amplification and bleeder circuit to export is changed out temperature independent electric current, with nonlinear effect and the temp-related effect that compensates described reference voltage.Described non-linear compensation circuit comprises: the 4th operational amplifier, and the positive input terminal of described the 4th operational amplifier is coupled to described reference voltage; The 7th transistor, the described the 7th transistorized source electrode is coupled to the negative input end of described the 4th operational amplifier, and the described the 7th transistorized grid is coupled to the output terminal of described the 4th operational amplifier, and described the 7th transistor also has drain electrode; Be biased in the 3rd BJT transistor of described temperature independent electric current; The temperature independent current mirror, be connected in described the 3rd transistor and described the 7th transistor, wherein, described the 4th operational amplifier and described the 7th transistor convert described reference voltage to described temperature independent electric current, and described temperature independent current mirror is incident upon described the 3rd transistor with described temperature independent current mirror; And first resistance and second resistance, be described non-linear voltage across the pressure drop of described first resistance and second resistance.

Perhaps, also can utilize another resistance and the transistorized combination of another BJT to reach the function of described amplification and bleeder circuit, the pressure drop of wherein said another resistance is positive temperature voltage and non-linear voltage sum, and the transistorized base-emitter voltage of described another BJT then is negative temperature voltage.

In addition, provide a kind of non-linear compensation circuit, be used for the nonlinear effect and the temp-related effect of the reference voltage that the compensation band gap reference circuit produced in further embodiment of this invention.Described bandgap reference circuit has: be biased in the first transistor and the transistor seconds of positive temperature current, and first resistance.Described non-linear compensation circuit comprises: operational amplifier receives described reference voltage; The 3rd transistor is connected to described operational amplifier, and described operational amplifier and described the 3rd transistor convert described reference voltage to temperature independent electric current; The temperature independent current mirror is with the described temperature independent electric current of mirror; The 4th transistor receives the described temperature independent electric current that described temperature independent current mirror is produced, and is biased in described temperature independent electric current; And second resistance and the 3rd resistance, non-linear voltage is across on described second resistance and described the 3rd resistance.

For above-mentioned and other feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and conjunction with figs. are described in detail below.

Description of drawings

Fig. 1 is the circuit diagram of well know bandgap reference circuit.

Fig. 2 is the compensation concept map of well know bandgap reference circuit.

Fig. 3 is the reference voltage-temperature profile figure of well know bandgap reference circuit.

Fig. 4 is using under the different voltage sources reference voltage of well know bandgap reference circuit-temperature profile figure.

Fig. 5 is the circuit diagram of the bandgap reference circuit of first embodiment of the invention.

Fig. 6 is the compensation concept map of the bandgap reference circuit of first embodiment of the invention.

Fig. 7 A and 7B are under the same electrical potential source, the reference voltage of first embodiment of the invention and known technology gained-temperature profile figure.

Fig. 8 is using under the different voltage sources reference voltage of the bandgap reference circuit of first embodiment of the invention-temperature profile figure.

Fig. 9 is the circuit diagram of the bandgap reference circuit of second embodiment of the invention.

Figure 10 A and 10B are the reference voltage-temperature profile figure of the bandgap reference circuit of second embodiment of the invention.

The main element description of symbols

100,500,500 ': bandgap reference circuit

M101～M103, M501～M506, M501 '～M506 ': MOS transistor

OP101～OP103, OP501～504, OP501 ', OP504 ': amplifier

R101～R103B, R501～R506, R501 '～R504 ', R506 ': resistance

B101～B102, B501～B503, B501 '～B504 ': BJT transistor

505,505 ': positive temperature current mirror

510,510 ': non-linear compensation circuit

515,515 ': the temperature independent current mirror

Embodiment

Fig. 5 is the circuit diagram of the band gap energy gap reference circuit of first embodiment of the invention.The bandgap reference circuit 500 of this embodiment comprises at least: by the formed positive temperature of MOS transistor M501～M503 (PTAT) current mirror 505, amplifier OP501～503, BJT transistor B501 and B502, resistance R 504, R505A, R505B and R506, and non-linear compensation circuit 510.Non-linear compensation circuit 510 comprises at least: by MOS transistor M504 and irrelevant (temperature independent) current mirror 515 of the formed temperature of M505, amplifier OP504, MOS transistor M506, BJT transistor B503, resistance R 501, R502 and R503.

The source electrode of MOS transistor M501 is connected to power vd D, and its drain electrode is connected to the emitter (that is node Va5) of BJT transistor B501, and its grid is connected to the output of amplifier OP501 and the grid of MOS transistor M502 and M503.The source electrode of MOS transistor M502 is connected to power vd D, and its drain electrode is connected to the emitter (that is node Vb5) of BJT transistor B502, and its grid is connected to the output of amplifier OP501 and the grid of MOS transistor M501 and M503.The source electrode of MOS transistor M503 is connected to power vd D, and its drain electrode is connected to the positive input terminal of amplifier OP502 and an end of resistance R 504, and its grid is connected to the output of amplifier OP501 and the grid of MOS transistor M501 and M502.The output of amplifier OP501 is coupled to the grid of MOS transistor M501～M503.By the operation of current mirror 505, can make MOS transistor M501～M503 all produce same current, because of its size all identical.

The positive input terminal of amplifier OP501 is connected to node Vb5, and its negative input end is connected to node Va5, and its output terminal is connected to the grid of MOS transistor M501～M503.The positive input terminal of amplifier OP502 is connected to drain electrode and the resistance R 504 of MOS transistor M503, and its negative input end then is connected to its output terminal, and its output terminal is connected to reference voltage V by resistance R 505A _BG5.The positive input terminal of amplifier OP503 is connected to node Va5, and its negative input end then is connected to its output terminal, and its output terminal is connected to reference voltage V by resistance R 505B _BG5.So, voltage V _NTC5 equal the V of transistor B501 _BE5AAs can be seen from Figure 5, the positive input terminal voltage of amplifier OP502 is V _PTC5+V _NL5.V _PTCThe positive temperature dependent voltage of 5 representatives, and V _NLRepresent nonlinear dependence voltage for 5.

The emitter of BJT transistor B501 is connected to node Va5, and its collector and base stage be ground connection all.The emitter of BJT transistor B502 is connected to node Vb5 by resistance R 506, and its collector and base stage be ground connection all.

Resistance R 504 is connected between the drain electrode and earth terminal of MOS transistor M503.Resistance R 505A and R505B are as voltage branch circuit, to tell V from the output voltage of amplifier OP502 and OP503 _BG5.Resistance R 505A is identical with the resistance value of R505B.Resistance R 506 is connected between the emitter of node Vb5 and BJT transistor B502.

The source electrode of MOS transistor M504 is connected to power vd D, and its grid is connected to drain electrode of itself and the grid of MOS transistor M505, and its drain electrode is connected to the drain electrode of MOS transistor M506.The source electrode of MOS transistor M505 is connected to power vd D, and its grid is connected to grid and the drain electrode of MOS transistor M504, and its drain electrode is connected to the emitter of BJT transistor B503.

The source electrode of MOS transistor M506 is connected to negative input end and the resistance R 503 of amplifier OP504, and its grid is connected to the output terminal of amplifier OP504, and its drain electrode is connected to drain electrode and the grid of MOS transistor M504.

The positive input terminal of amplifier OP504 is connected to reference voltage V _BG5, its negative input end is connected to source electrode and the resistance R 503 of MOS transistor M506, and its output terminal is connected to the grid of MOS transistor M506.

The emitter of BJT transistor B503 is connected to drain electrode, resistance R 501 and the R502 of MOS transistor M505, and its base stage and collector be ground connection all.

Resistance R 501 is connected between the emitter of the emitter of BJT transistor B501 and BJT transistor B503, and electric current I is arranged on it _NL5 pass through, and it is V across voltage _NL5.Resistance R 502 is connected between the emitter of node Vb5 and BJT transistor B503, and electric current I is equally arranged on it _NL5 pass through, and it equally is V across voltage _NL5.Resistance R 501 interconnects with R502, and both resistance values are identical.Resistance R 503 is connected between the source electrode and earth terminal of MOS transistor M506.

The output voltage of amplifier OP501 can be adjusted MOS transistor M501 and M503, makes Va5=Vb5, and then makes and cause △ V on the resistance R 506 _BE5 pressure drop.Pressure drop △ V across resistance R 506 _BE5 can be expressed as follows:

△V _BE5＝V _T*ln(n) (8)

N then be BJT transistor B502 with the size of B501 than (n:1).

Explain that for convenient the beneath electric current that MOS transistor M501～M503 is produced is decided to be I _PTAT5+I _NL5.I _PTATThe positive temperature dependent current of 5 representatives, and I _NLRepresent the nonlinear dependence electric current for 5.

Because the output current of MOS transistor M503 is I _PTAT5+I _NL5, so can produce pressure drop on resistance R 504, this voltage drop value is R504* (I _PTAT5+I _NL5)=V _PTC5+V _NL5, V _PTCThe positive temperature dependent voltage of 5 representatives, and V _NLRepresent nonlinear dependence voltage for 5.Therefore, the positive input terminal magnitude of voltage of amplifier OP502 is V _PTC5+V _NL5.

In addition, because the positive input terminal magnitude of voltage V of amplifier OP503 _NTC5 equal V _BE5A,, can obtain by the operation of amplifier OP502 and OP503

V _BG5＝0.5*(V _PTC5+V _NTC5+V _NL5) (9)

Because transistor B501 and B502 are subjected to the bias voltage of PTAT (proportional to absolutetemperature, positive temperature coefficient (PTC)) electric current, so its α=1.So V _BE5AWith V _BE5BCan be expressed as:

V _BE5A＝V _BE5B＝V _G0-(V _G0-V _BE0)*T/T ₀-(η-1)*V _Tln(T/T ₀) (10)

V _BE5AWith V _BE5BIt is the negative temperature associated voltage.Owing in equation 9, see that still non-linear voltage V is arranged _NL5 existence, so present embodiment utilizes non-linear compensation circuit 510 to estimate and compensating non-linear voltage V _NL5.

As shown in Figure 5, reference voltage V _BG5 can be fed back to the positive input terminal of the amplifier OP504 in the non-linear compensation circuit 510.Amplifier OP504, MOS transistor 506 can be considered a voltage-to-current converting unit, and it is with reference voltage V _BG5 convert electric current I to _BG5.Electric current I _BG5 can be considered temperature independent electric current.Current mirror 515, it is the irrelevant current generator of temperature, electric current I that can this is temperature independent _BG5 map to MOS transistor M505 and BJT transistor B503.Because the bias current of BJT transistor B503 has nothing to do in temperature, α can be considered as 0.So,

V _BE5C＝V _G0-(V _G0-V _BE0)*T/T ₀-(η)*V _Tln(T/T ₀) (11)

Equation (10) and equation (11) are subtracted each other and can get:

$V_{\mathrm{BE}5A}-V_{\mathrm{BE}5C}=V_T\ln \frac{T}{T_0}---\left(12\right)$

From equation (7) as can be known, the nonlinear terms of reference voltage are V _TLn (T/T ₀)=V _NL5.In order to estimate out the value of non-linear voltage, in the present embodiment, make resistance R 501 be across between the emitter of the emitter of BJT transistor B501 and B503.Therefore, be non-linear voltage V across the pressure drop on resistance R 501 (and resistance R 502) _NL5.

Therefore, can put in order again:

${\mathrm{<figure-callout\; id="5"\; label="V\; BG"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BG}}=\frac{1}{2}({\mathrm{<figure-callout\; id="5"\; label="V\; NTC"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{NTC}}+{\mathrm{<figure-callout\; id="5"\; label="V\; PTC"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{PTC}}+V_{\mathrm{NL}5})=\frac{1}{2}\&times;[V_{\mathrm{BE}5A}+R504\&CenterDot;(\frac{\mathrm{\&Delta;}{V}_{\mathrm{BE}5}}{R506}+\frac{V_{\mathrm{NL}}}{R02})]$

$=\frac{1}{2}\&times;\{[V_{\mathrm{BG}5}-(V_{\mathrm{BG}5}-V_{\mathrm{BE}0})\frac{T}{T_0}-(\mathrm{\&eta;}-1)V_T\ln \frac{T}{T_0}]+[\frac{R504}{R506}\&CenterDot;V_T\&CenterDot;\ln \left(n\right)]+\left[\frac{R504}{R502}{V}_T\ln \frac{T}{T_0}\right]\}$

(13)

Wherein η and V _BE0 definition such as above-mentioned.By suitable selection resistance value R504 and R502, to make (η-1) to equal or very near the ratio of (R504/R502), then equation (13) can be simplified to

${\mathrm{<figure-callout\; id="5"\; label="V\; BG"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BG}}=\frac{1}{2}\&times;\{[V_{\mathrm{BG}5}-(V_{\mathrm{BG}5}-V_{\mathrm{BG}0})\frac{T}{T_0}]+[\frac{R504}{R506}\&CenterDot;V_T\&CenterDot;\ln \left(n\right)]\}---\left(14\right)$

Can find out through after the compensation of non-linear compensation circuit 510 reference voltage V by equation 14 _BG5 nonlinear effect has obtained good compensation, can be considered be in close proximity to temperature independent.

Non-linear compensation circuit 510 is the reference voltage V that utilizes feedback _BG5 (they can be regarded as more temperature independent) produce and are considered as more temperature independent electric current I _BG5.In addition, two resistance R 501 in the non-linear compensation circuit 510 are across transistor B501/B502 (α=1 with R502, it is subjected to the bias voltage of positive temperature dependent current) nothing to do with temperature transistor (α=0, it is subjected to the bias voltage of irrelevant temperature current), in order to estimate out non-linear voltage V _NL5.

Fig. 6 is the compensation concept map of the bandgap reference circuit of this first embodiment.Fig. 6 demonstrates, the reference voltage V that this first embodiment is produced _BGBe by K3*V _T(tool positive temperature coefficient (PTC)), V _BE(negative temperature coefficient) and V _NL(nonlinear compensation item) addition forms, and wherein K3 is a constant, K3=R504/R506*ln (n).As can be seen from Figure 6, in this first embodiment, be contained in V originally _BEInterior nonlinear effect is by V _NLInstitute's good compensation.Therefore in operating temperature range, the curve of the performance plot of reference voltage (imperfect) phenomenon relaxes than Fig. 2.

Fig. 7 A and 7B are under the same electrical potential source (VDD=1.2V), the reference voltage-temperature profile figure of this first embodiment and known technology gained.With this understanding, the mobility scale of the reference voltage of known technology is 6.28mV; With this understanding, and originally, the mobility scale of the reference voltage of first embodiment has only 0.711mV.Can find out obviously that the mobility scale of the reference voltage of this first embodiment has been dwindled many.

Fig. 8 be this first embodiment in operating temperature between-40 ℃～125 ℃, different power vd D (under the 10.V～1.5V), measured reference voltage V _GB-temperature profile figure.Wherein, curve A 5～E5 represents the V under the situation of VDD=1.5V, VDD=1.4V, VDD=1.3V, VDD=1.2V and VDD=1.1V respectively _GBThe change curve.

Fig. 9 is the circuit diagram of the bandgap reference circuit 500 ' of second embodiment of the invention.The framework of bandgap reference circuit 500 ' is basically similar in appearance to the bandgap reference circuit 500 of Fig. 5, so the identical or similar elements of identical or similar reference marker representative.BJT transistor B504 ' and the resistance R 504 ' that amplifier OP502, OP503 and the resistance R 504 of Fig. 5 replaced to Fig. 9 just.

Utilize the notion of Fig. 5, utilize the reference voltage V that framework produced of Fig. 9 as can be known _BG5 ' can be expressed as follows:

${\mathrm{<figure-callout\; id="5"\; label="V\; BG"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BG}}=V_{\mathrm{NTC}}\&prime;+V_{\mathrm{PTC}}\&prime;=[V_{\mathrm{BE}5D}+R504\&prime;\&CenterDot;(\frac{{\mathrm{\&Delta;V}}_{\mathrm{BE}5\&prime;}}{R506}+\frac{{\mathrm{<figure-callout\; id="5"\; label="V\; NL"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{NL}}}{R502\&prime;})]$

$=\{[{\mathrm{<figure-callout\; id="5"\; label="V\; BG"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BG}}5\&prime;-({\mathrm{<figure-callout\; id="5"\; label="V\; BG"\; filenames="C200610076590E00261.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BG}}5\&prime;-V_{\mathrm{BE}0})\frac{T}{T_0}-(\mathrm{\&eta;}-1)V_T\ln \frac{T}{T_0}]+[\frac{R504\&prime;}{R506\&prime;}\&CenterDot;V_T\&CenterDot;\ln \left(n\right)]+\left[\frac{R504\&prime;}{R502\&prime;}{V}_T\ln \frac{T}{T_0}\right]\}$

(15)

In Fig. 9, same or similar element in Fig. 5 is all represented with similar mark.Because the operation of the bandgap reference circuit 500 ' of Fig. 9 can be released for class the description of bandgap reference circuit 500 from above-mentioned, so no longer repeat at this.

Figure 10 A and 10B are the reference voltage-temperature profile figure of the bandgap reference circuit of second embodiment.Figure 10 B is the partial enlarged drawing of Figure 10 A.Can find out that from Figure 10 B in a second embodiment, the mobility scale of reference voltage has narrowed down to has only 1.46mV.

From the framework of Fig. 5 and Fig. 9 as can be known, non-linear compensation circuit of the present invention is applicable among the existing bandgap reference circuit of major part.

In sum as can be known, non-linear compensation circuit of the present invention can increase the accuracy of reference voltage.And the circuit cost of this non-linear compensation circuit is not high, so but widespread use.

Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; any person of ordinary skill in the field; without departing from the spirit and scope of the present invention; when change and the improvement that can do slightly, so protection scope of the present invention is as the criterion when looking the claim person of defining.

Claims (17)

1. bandgap reference circuit is characterized in that comprising:

Positive temperature current mirror produces positive temperature current and non-linear current;

The first transistor is connected in described positive temperature current mirror, is biased in the described positive temperature current that described positive temperature current mirror is exported;

Transistor seconds is biased in the described positive temperature current that described positive temperature current mirror is exported;

The 3rd resistance is connected between described positive temperature current mirror and the described transistor seconds;

Amplify and bleeder circuit, feedback is in the base-emitter voltage of described the first transistor, positive temperature voltage and non-linear voltage and output reference voltage; And

Non-linear compensation circuit, the described reference voltage that utilizes described amplification and bleeder circuit to export is changed out temperature independent electric current, and described non-linear compensation circuit comprises:

The 4th operational amplifier, the positive input terminal of described the 4th operational amplifier is coupled to described reference voltage;

The 7th transistor, the described the 7th transistorized source electrode is coupled to the negative input end of described the 4th operational amplifier, and the described the 7th transistorized grid is coupled to the output terminal of described the 4th operational amplifier, and described the 7th transistor also has drain electrode;

The 3rd transistor is biased in described temperature independent electric current;

The temperature independent current mirror, be connected in described the 3rd transistor and described the 7th transistor, wherein, described the 4th operational amplifier and described the 7th transistor convert described reference voltage to described temperature independent electric current, and described temperature independent current mirror is incident upon described the 3rd transistor with described temperature independent current mirror;

First resistance is connected in described the first transistor and described the 3rd transistor, is described non-linear voltage across the pressure drop of described first resistance; And

Second resistance is connected in described the 3rd transistor, is described non-linear voltage across the pressure drop of described second resistance;

By described non-linear compensation circuit, can compensate the nonlinear effect and the temp-related effect of described reference voltage.

2. bandgap reference circuit according to claim 1 is characterized in that:

Pressure drop across described the 3rd resistance is V _T* ln (n), V _TBe the critical voltage of described transistor seconds, n is the dimension ratio of described transistor seconds to described the first transistor.

3. bandgap reference circuit according to claim 2 is characterized in that also comprising:

The 4th resistance, be connected between described positive temperature current mirror and the earth terminal, described positive temperature current that described positive temperature current mirror is exported and described non-linear current described the 4th resistance of can flowing through is described positive temperature voltage and described non-linear voltage with order across the pressure drop of described the 4th resistance.

4. bandgap reference circuit according to claim 3 is characterized in that described positive temperature current mirror comprises:

The 4th transistor, the described the 4th transistorized source electrode is coupled to power supply, and described the 4th transistor drain is coupled to the emitter of described the first transistor;

The 5th transistor, the described the 5th transistorized source electrode is coupled to described power supply, and described the 5th transistor drain is coupled to described the 3rd resistance; And

The 6th transistor, the described the 6th transistorized source electrode is coupled to described power supply, and described the 6th transistor drain is coupled to described the 4th resistance;

Wherein said the 4th, the 5th and the 6th transistor is exported described positive temperature current and described non-linear current.

5. bandgap reference circuit according to claim 4 is characterized in that also comprising:

First operational amplifier, the positive input terminal of described first operational amplifier is coupled to described the 3rd resistance, the negative input end of described first operational amplifier is coupled to the emitter of described the first transistor, and the output terminal of described first operational amplifier is coupled to described the the 4th, the 5th and the 6th transistorized grid;

Wherein, described first operational amplifier amplifies the pressure reduction between the voltage of the voltage of described positive input terminal and described negative input end, to drive described positive temperature current mirror.

6. bandgap reference circuit according to claim 4 is characterized in that described amplification and bleeder circuit comprise:

Second operational amplifier, the positive input terminal of described second operational amplifier are coupled to the described the 6th transistorized described drain electrode and described the 4th resistance, and the output terminal of described second operational amplifier is fed back to the negative input end of described second operational amplifier;

The 5th resistance is connected between the described output terminal and described reference voltage of described second operational amplifier;

The 3rd operational amplifier, the positive input terminal of described the 3rd operational amplifier is coupled to the emitter of described the first transistor, and the output terminal of described the 3rd operational amplifier is fed back to the negative input end of described the 3rd operational amplifier; And

The 6th resistance is connected between the described output terminal and described reference voltage of described the 3rd operational amplifier;

The voltage of the output terminal of described the 5th resistance and described the 6th electric resistance partial pressure described second and the 3rd operational amplifier is to produce described reference voltage.

7. bandgap reference circuit according to claim 4 is characterized in that described non-linear compensation circuit also comprises:

The 7th resistance is connected between the described the 7th transistorized described source electrode and the described earth terminal.

8. bandgap reference circuit according to claim 7 is characterized in that described temperature independent current mirror comprises:

The 8th transistor, the described the 8th transistorized source electrode is coupled to described power supply, and described the 8th transistor drain is coupled to the described the 7th transistorized described drain electrode, and the described the 8th transistorized grid is coupled to the described the 8th transistorized described drain electrode; And

The 9th transistor, the described the 9th transistorized source electrode is coupled to described power supply, and described the 9th transistor drain is coupled to the described the 3rd transistorized emitter, and the described the 9th transistorized grid is coupled to the described the 8th transistorized described grid.

9. bandgap reference circuit according to claim 8, it is characterized in that described the first transistor has emitter, base stage and collector, the emitter of the first transistor be connected to described first operational amplifier described negative input end, be connected to described the 3rd amplifier described positive input terminal, be connected to the described the 4th transistorized described drain electrode and described first resistance; The equal ground connection of the base stage of the first transistor and collector.

10. bandgap reference circuit according to claim 9 is characterized in that described transistor seconds has emitter, base stage and collector, and the emitter of transistor seconds is connected to described second resistance, the equal ground connection of the base stage of transistor seconds and collector.

11. bandgap reference circuit according to claim 10, it is characterized in that described the 3rd transistor has emitter, base stage and collector, the 3rd transistorized emitter is connected to described the 9th transistor drain, is connected to described first resistance and described second resistance; The 3rd transistorized base stage and the equal ground connection of collector,

Wherein, described first resistance is connected between the emitter and the 3rd transistorized emitter of described the first transistor, and described second resistance is connected between described the 3rd resistance and the 3rd transistorized emitter.

12. non-linear compensation circuit, the nonlinear effect and the temp-related effect that are used for the reference voltage that the compensation band gap reference circuit produced, it is characterized in that described bandgap reference circuit has: the first transistor and the transistor seconds that are biased in positive temperature current, and first resistance, described non-linear compensation circuit comprises:

Operational amplifier receives described reference voltage;

The 3rd transistor is connected to described operational amplifier, and described operational amplifier and described the 3rd transistor convert described reference voltage to temperature independent electric current;

The temperature independent current mirror is connected in described the 3rd transistor, with the described temperature independent electric current of mirror;

The 4th transistor receives the described temperature independent electric current that described temperature independent current mirror is produced, and is biased in described temperature independent electric current;

Second resistance is connected to described the first transistor and described the 4th transistor, has non-linear voltage to be across described second resistance, and

The 3rd resistance is connected to described first resistance and described the 4th transistor, and described non-linear voltage is across described the 3rd resistance.

13. non-linear compensation circuit according to claim 12 is characterized in that described operational amplifier has: receive the positive input terminal of described reference voltage, negative input end and output terminal.

14. non-linear compensation circuit according to claim 13 is characterized in that described

The 3rd transistorized source electrode is connected to the negative input end of described operational amplifier, and the described the 3rd transistorized grid is connected to the output terminal of described operational amplifier, and described the 3rd transistor also comprises drain electrode.

15. non-linear compensation circuit according to claim 14 is characterized in that:

Described the first transistor has: be connected to the emitter of described second resistance, and the collector of the base stage of ground connection and ground connection; And

Described transistor seconds has: be connected to the emitter of described first resistance, and the collector of the base stage of ground connection and ground connection.

16. non-linear compensation circuit according to claim 15 is characterized in that described the 4th transistor has: be connected to described temperature independent current mirror, the emitter of described second resistance and described the 3rd resistance; And the collector of the base stage of ground connection and ground connection.

17. non-linear compensation circuit according to claim 16 is characterized in that described temperature independent current mirror comprises:

The 5th transistor, the described the 5th transistorized source electrode is coupled to power supply, and described the 5th transistor drain is coupled to described the 3rd transistor drain, and the described the 5th transistorized grid is coupled to the described the 5th transistorized described drain electrode; And

The 6th transistor, the described the 6th transistorized source electrode is coupled to described power supply, and described the 6th transistor drain is coupled to the described the 4th transistorized emitter, and the described the 6th transistorized grid is coupled to the described the 5th transistorized described grid.

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