CN1912793A - High temp stability reference voltage source corrected by 1V power supply non-linear technology - Google Patents

Abstract

A reference voltage source of integrated circuit is featured as applying nonlinear correction technique to counterbalance logarithmic term in temperature coefficient of output current to make outputted voltage source have very high temperature stabilization, applying level displacement circuit to replace traditional voltage dividing resistance for decreasing temperature influence caused by area and resistance, varying value of parallel internal resistance at output end for realizing large variation of voltage value with temperature stabilization, setting startup and offset circuit to let circuit start up correctly.

Description

The high-temperature stability reference voltage source that the 1V power supply non-linear is corrected

Technical field

The present invention relates to the power supply of integrated circuit, especially the temperature stability technical field of reference voltage source.

Background technology

Voltage-reference is being widely used in a lot of mimic channels and Digital Analog Hybrid Circuits, for example: A D, D the A converter, storer or the like.Along with the continuous reduction of technology characteristics size, consider the reliability of device, the supply voltage that circuit working allowed also must progressively reduce; Simultaneously, because the progressively raising of transistor integrated level, the power consumption of circuit also must be limited.Thereby in low-voltage, under the harsh conditions, Circuits System is more and more stricter to the requirement of voltage reference source module day by day for low-power consumption and working environment.

For traditional band-gap reference source circuit, under the 1V supply voltage, there are two tangible factors restricting the realization of circuit.The one, the output of band gap reference is approximately 1.2V, has exceeded the scope of supply voltage; Another is that the input common-mode range of the operational amplifier (OPA) used in the reference source circuit is restricted.These two restraining factors can be respectively method by current-mode and electric resistance partial pressure solve.The reference source circuit of some 1V supply voltages was in the news, but, what these reference source circuits were used is Bipolar or BiCMOS technology, cost is higher, as: P.Malcovati, F.Maloberti, et al. " Curvaturecompensated BiCMOS bandgap with 1-V supply voltage; " IEEE Journal of Solid-State Circuits, vol.37, pp.526-529, the CMOS reference source circuit of April 2002. other reports has very high temperature stabilization characteristic, but for having the logarithmic term that temperature relies on, they have just carried out single order, second order, or corresponding curve is corrected, and do not have whole this logarithmic terms that balances out, as: Hironori Banba, Hitoshi Shiga, et al. " A CMOS Bandgap ReferenceCircuit with Sub-1-v Operation; " IEEE Journal of Solid-State Circuits, vol.34, no.5, May 1999. is in the present invention, we have proposed supply voltage is the brightness nonlinear correction CMOS reference voltage source of 1V, attempts fundamentally all to offset the high temperature stability that the logarithmic term about temperature obtains.Electric resistance partial pressure is not used in the realization of circuit, but has adopted the method for level shift, can reduce the temperature effect that area and resistance bring so as far as possible.

Summary of the invention

The object of the present invention is to provide a kind of reference voltage source that obtains the high-temperature stability of 1V power supply non-linear correction by whole counteractings about the logarithmic term of temperature.

The invention is characterized in:

The 1st operational amplifier (OPA1), output terminal are connected to metal-oxide-semiconductor (M0) and grid (M1) simultaneously, and the source electrode of described (M0) pipe, (M1) pipe meets power vd D simultaneously; The positive input terminal of described the 1st operational amplifier (OPA1) is node (V _p), this node (V _p) in the drain electrode that is connected to (M0) pipe, also be connected to PNP transistor (Q by resistance (R0) ₀) emitting stage, should (Q ₀) all the other two-terminal-groundings of pipe; The negative input end of described the 1st operational amplifier (OPA1) is node (Vn), and this node (Vn) is also connected to PNP transistor (Q in the drain electrode that is connected to (M1) pipe ₁) emitter, should (Q ₁) all the other two-terminal-groundings of pipe, because the retroactive effect of the 1st operational amplifier (OPA1) and metal-oxide-semiconductor (M0), (M1) makes node (V _P) equal with the voltage of node (Vn);

The 2nd operational amplifier (OPA2), the grid of output termination metal-oxide-semiconductor (M4), the source electrode that is somebody's turn to do (M4) pipe meets power vd D; The negative input end of described the 2nd operational amplifier (OPA2) connects described node (Vn), and the positive input terminal of described the 2nd operational amplifier (OPA2) is when receiving the drain electrode of described (M4) pipe, also by resistance (R1) ground connection;

The 3rd operational amplifier (OPA3), the grid of output termination metal-oxide-semiconductor (M7), and being somebody's turn to do the positive input terminal of drain feedback to the 3 operational amplifiers (OPA3) of (M7) pipe, the positive input terminal of the 3rd operational amplifier (OPA3) is through resistance (R2) ground connection, and negative input end meets PNP transistor (Q ₂) emitter, should (Q ₂) all the other two-terminal-groundings of pipe;

Metal-oxide-semiconductor (M5), (M2), both source electrodes meet power vd D, and drain electrode connects the negative input end of described the 3rd operational amplifier (OPA3) after linking to each other, (M5) grid of pipe is received the output terminal of described the 2nd operational amplifier (OPA2), and (M2) grid of pipe then connects the output terminal of described the 1st operational amplifier (OPA1);

Metal-oxide-semiconductor (M8), (M9), the source electrode that is somebody's turn to do (M8) pipe meets power vd D, and drain electrode connects the drain and gate of (M9) pipe simultaneously, is somebody's turn to do the source ground of (M9) pipe;

Metal-oxide-semiconductor (M6), (M10), the source electrode that is somebody's turn to do (M6) pipe meets power vd D, and grid is received the output terminal of described the 2nd operational amplifier (OPA2), the drain electrode of being somebody's turn to do (M6) pipe simultaneously connects the drain electrode of (M10) pipe, form the output terminal Vbg of described reference voltage source, and (M10) grid of pipe links to each other with the grid of described (M9) pipe, but (M10) source ground of pipe;

Metal-oxide-semiconductor (M3), source electrode meets power vd D, and grid connects the output terminal of described the 1st operational amplifier (OPA1), and resistance (R3) and the mid point (R4) that is serially connected between described output terminal Vbg and the ground received in the drain electrode of being somebody's turn to do (M3);

Described (R ₀)=8k Ω～12k Ω;

(R ₁) at the described (Q that passes through ₂) the condition that do not change with temperature T substantially of electric current under differentiate obtains to temperature,

$R_1=(\mathrm{\η}-x+\frac{V_{g0}-V_{\mathrm{be}}\left(T_r\right)}{V_{T_r}})\frac{R_0}{\ln n}$

Wherein, V _G0The pn junction diode voltage that extrapolation obtains when being 0K, V _Be(T _r) be in temperature T _rThe time voltage between base stage and the emitter, x is that the temperature that flows through transistor current relies on parameter, η is temperature independent and relevant with technology parameter, value between 3.6 to 4, V _T=kT/q is a thermal voltage, and k is a Boltzmann constant (1.38 * 10 ^-23J/K), q is an electron charge (1.6 * 10 ^-19C), T is an absolute temperature, and n is described transistor (Q ₀) and (Q ₁) the ratio of emitter area;

(R ₂) at the output current I of described reference voltage source _BgIn the logarithmic term of temperature be to obtain under zero the condition,

$R_2=\frac{\mathrm{\&eta;}}{\mathrm{\&eta;}-1}{\mathrm{<figure-callout\; id="1"\; label="R"\; filenames="A20061011259700101.png"\; state="\{\{state\}\}">R</figure-callout>}}_1$

(R3), (R4) linear compensation relation and desired output reference voltage as requested obtain,

$R_4=\frac{(V_{g0}-V_{\mathrm{be}}\left(T_r\right))V_{\mathrm{bg}}}{V_{T_r}{V}_{g0}\ln n}{R}_0$

$R_3=\frac{V_{\mathrm{bg}}}{V_{g0}}\frac{R_1{R}_2}{R_2-R_1}-R_4$

The invention has the advantages that:

1. among the present invention, adopted the brightness nonlinear correction technology to offset V _BeIn the nonlinear temperature item, the reference voltage source that obtains has very high temperature stability.

2. can change R in the core circuit according to actual needs ₃, R ₄Resistance value, the output voltage of reference source just can change on a large scale, and all has very high temperature stability, modulability is good.

3. the CMOS technology of Fa Ming reference voltage source circuit available standards realizes, and in operational amplifier integrated level shift circuit, replaced traditional divider resistance, saved area.

4. start-up circuit practicability and effectiveness, and be easy to control, core circuit can correctly start after having guaranteed to power on.

5. designed band gap reference can be used in the mobile device Circuits System of low supply voltage.

Description of drawings

Fig. 1. the circuit diagram of the reference voltage source of brightness nonlinear correction;

Fig. 2. the circuit diagram of the operational amplifier that the present invention adopts;

Fig. 3. startup and biasing circuit synoptic diagram that the present invention adopts;

The temperature characteristics of the reference voltage source under Fig. 4 .1V power supply;

Fig. 5. the reference voltage source output voltage is with the family curve of mains voltage variations.

Embodiment

The bipolar transistor of a forward job, the voltage V between its base stage and the emitter _BeWith variation of temperature is not linear, and itself and variation of temperature relation can be expressed as:

$V_{\mathrm{be}}=V_{g0}-\frac{T}{T_r}[V_{g0}-V_{\mathrm{be}}\left(T_r\right)]-(\mathrm{\&eta;}-x)V_T\ln \left(\frac{T}{T_r}\right)---\left(1\right)$

Wherein, V _G0The pn junction diode voltage that extrapolation obtains when being 0K, T is an absolute temperature, V _Be(T _r) be in temperature T _rThe time voltage between base stage and the emitter, x is that the temperature that flows through transistor current relies on parameter, η is temperature independent and relevant with technology parameter, value between 3.6 to 4, V _T=kT/q is a thermal voltage, and k is a Boltzmann constant (1.38 * 10 ^-23J/K), q is an electron charge (1.6 * 10 ^-19C).The general way of temperature compensation is in temperature T _rThe place carries out Taylor expansion to (1) formula, so, just can obtain about single order, second order and the high-order related coefficient of temperature.Thereby, can adopt corresponding opposite temperature to rely on item and offset.But our purpose is just to balance out nonlinear terms on the whole, and does not carry out Taylor expansion, just almost entirely offsets V _BeThe logarithmic term of middle temperature dependent.

Fig. 1 is a reference voltage source core circuit structure of having utilized the brightness nonlinear correction technology, comprises 3 OPA, matching current mirror, resistance and some longitudinal P NP transistors (available parasitic components in the CMOS standard technology).

The collector current of bipolar transistor can become by approximate expression:

$I_c=I_s{e}^{\frac{q{V}_{\mathrm{be}}}{\mathrm{kT}}}---\left(2\right)$

Wherein, I _cBe to flow through transistorized electric current, I _sBe reverse saturated bias current, the voltage that can be obtained between base stage and the emitter by (2) formula is so:

$V_{\mathrm{be}}=V_T\ln \frac{I_c}{I_s}---\left(3\right)$

As shown in Figure 1, since the retroactive effect of amplifier OPA1 and MOS transistor M0, M1, node V _pAnd V _nThe voltage at place will equate.So, utilize our electric current that can obtain one be directly proportional with temperature (PTAT) of (3) formula to be shown below:

$I_{\mathrm{PTAT}}=\frac{V_{\mathrm{be}1}-V_{\mathrm{be}0}}{R_0}=\frac{V_T\ln n}{R_0}---\left(4\right)$

N is the ratio of the emitter area of transistor Q0 and Q1 in the following formula.In like manner as can be known, also have other two feedback control loops among Fig. 1: the one, form by OPA2, M4 and R1; Another is made up of OPA3, M7 and R2.So we can obtain two current expressions with negative temperature coefficient (CTAT):

$I_{\mathrm{<figure-callout\; id="1"\; label="CTAT"\; filenames="A20061011259700101.png"\; state="\{\{state\}\}">CTAT</figure-callout>}1}=\frac{V_{\mathrm{be}1}}{R_1}---\left(5\right)$

$I_{\mathrm{CTAT}2}=\frac{V_{\mathrm{be}2}}{R_2}---\left(6\right)$

Equation (1) is updated to (5) respectively, (6) two formulas, so the CTAT electric current just can be transformed to:

$I_{\mathrm{<figure-callout\; id="1"\; label="CTAT"\; filenames="A20061011259700101.png"\; state="\{\{state\}\}">CTAT</figure-callout>}1}=\frac{1}{R_1}(V_{g0}-\frac{T}{T_r}(V_{g0}-V_{\mathrm{be}1}\left(T_r\right))-(\mathrm{\&eta;}-x_1)V_T\ln \left(\frac{T}{T_r}\right))---\left(7\right)$

$I_{\mathrm{CTAT}2}=\frac{1}{R_2}(V_{g0}-\frac{T}{T_r}(V_{g0}-V_{\mathrm{be}2}\left(T_r\right))-(\mathrm{\&eta;}-x_2)V_T\ln \left(\frac{T}{T_r}\right))---\left(8\right)$

Among Fig. 1, what flow through transistor Q1 is the PTAT electric current, so x as can be known ₁=1; Simultaneously, the electric current of transistor Q2 is the CTAT electric current sum that flows through the PTAT electric current of M2 and flow through M5.According to equation (4) and (5), can obtain:

$I_{Q2}=I_{\mathrm{PTAT}}+{\mathrm{<figure-callout\; id="1"\; label="I\; CTAT"\; filenames="A20061011259700101.png"\; state="\{\{state\}\}">I</figure-callout>}}_{\mathrm{CTAT}}=\frac{V_T\ln n}{R_0}+\frac{V_{\mathrm{be}1}}{R_1}---\left(9\right)$

This just means if select suitable resistance R ₀And R ₁, the electric current that flows through Q2 just can be realized the first compensation phase about temperature, i.e. x ₂≈ 0.Therefore, according to equation (7) and (8), flow through the electric current I of M6 _CTAT1Cut the electric current I that flows through M10 _CTAT2, the result is:

$I_{\mathrm{CTAT}1}-I_{\mathrm{CTAT}2}=(\frac{1}{R_1}-\frac{1}{R_2})V_{g0}-(\frac{1}{R_1}-\frac{1}{R_2})\left((V_{g0}-V_{\mathrm{be}}\left(T_r\right))\frac{T}{T_r}\right)-(\frac{(\mathrm{\&eta;}-1)V_T}{R_1}-\frac{\mathrm{\&eta;}{V}_T}{R_2})\ln \left(\frac{T}{T_r}\right)---\left(10\right)$

In equation (10), first is constant, and second is the linear term about temperature, and last then is the logarithmic term about temperature.Because η is temperature independent numerical value, so choose the resistance R of proper proportion ₁And R ₂, logarithmic term just can eliminate fully.But,, might still exist about the linear term of temperature even the logarithmic term in (10) formula is eliminated.We just need extra PTAT electric current to compensate so, flow through the electric current I of transistor M3 among Fig. 1 _PTATSolved this problem.Expression formula that we can obtain being correlated with and output reference voltage are:

$(\frac{1}{R_1}-\frac{1}{R_2})\frac{T}{T_r}(V_{g0}-V_{\mathrm{be}}\left(T_r\right))(R_3+R_4)=\frac{V_T\ln n}{R_0}{R}_4---\left(11\right)$

$V_{\mathrm{bg}}=(\frac{1}{R_1}-\frac{1}{R_2})V_{g0}(R_3+R_4)---\left(12\right)$

By equation (11) and (12) as can be seen, regulate resistance R ₃And R ₄Value, we can obtain to have on a large scale the reference voltage of high-temperature stability.

Because the operational amplifier of using in the reference voltage source circuit is to work under the 1V supply voltage, so we have adopted the folding structure in the two poles of the earth as shown in Figure 2.

At room temperature T _rDown, the base stage of bipolar transistor Q1 and Q2 and the voltage approximately equal between the emitter are approximately:

V _be1(V _T)≈V _be2(V _T)≈0.65V (13)

By (13) formula as can be known the input common mode electrical level of OPA under reference voltage source steady operation situation be approximately 0.65V, we have adopted level shift circuit, reduce the input common mode electrical level of amplifier.Level shift circuit is made up of the M1-M4 pipe, is used for replacing divider resistance.Under the steady operation situation, M7～M9 will be operated in the saturation region, and M5 and M6 end.In the circuit start stage, even M1, M3, M7 and M8 are in cut-off state, but M5, M6 and M10 are operated in the saturation region, can provide the gain of almost stable to guarantee that circuit can start fast, that is to say, no matter when, it is work that differential pair M5 and M6, M7 and M8 have at least a pair of.

When powering up to band gap reference, can operate as normal in order to make circuit, also need corresponding the startup and biasing circuit, its topological structure is as shown in Figure 3.En is the control enable signal, and vbiasp and vbiasn are output offset voltage, offer operational amplifier shown in Figure 2.The course of work of Fig. 3 circuit is as follows: when En was low level, vbiasp and vbiasn then were respectively VDD and VSS, and OPA can not work, so whole band gap reference just is under an embargo; When En becomes high level, M2-M4 will be operated in the saturation region, provides suitable vbiasp and vbiasn to start reference source circuit to OPA.

The temperature characterisitic of reference voltage source output voltage as shown in Figure 4.When temperature when between 100 ℃, changing for 15 ℃, output voltage has only the deviation of 0.5mV, temperature coefficient is about 16.7ppm/ ℃.Shown in Figure 5 is under the room temperature, and the voltage reference of output is with the mains voltage variations family curve.When supply voltage was 0.98V as can be seen, band gap reference can operate as normal.Under the 1V supply voltage, output voltage is 351.9mV; When supply voltage changed at 1V～1.4V, the output voltage deviation was 1.4mV, reaches 0.4%.

Claims (3)

1.1V the high-temperature stability reference voltage source that power supply non-linear is corrected is characterized in that, contains:

The 1st operational amplifier (OPA1), output terminal are connected to metal-oxide-semiconductor (M0) and grid (M1) simultaneously, and the source electrode of described (M0) pipe, (M1) pipe meets power vd D simultaneously; The positive input terminal of described the 1st operational amplifier (OPA1) is node (V _P), this node (V _P) in the drain electrode that is connected to (M0) pipe, also be connected to PNP transistor (Q by resistance (R0) ₀) emitting stage, should (Q ₀) all the other two-terminal-groundings of pipe; The negative input end of described the 1st operational amplifier (OPA1) is node (Vn), and this node (Vn) is also connected to PNP transistor (Q in the drain electrode that is connected to (M1) pipe ₁) emitter, should (Q ₁) all the other two-terminal-groundings of pipe, because the retroactive effect of the 1st operational amplifier (OPA1) and metal-oxide-semiconductor (M0), (M1) makes node (V _P) equal with the voltage of node (Vn);

The 2nd operational amplifier (OPA2), the grid of output termination metal-oxide-semiconductor (M4), the source electrode that is somebody's turn to do (M4) pipe meets power vd D; The negative input end of described the 2nd operational amplifier (OPA2) connects described node (Vn), and the positive input terminal of described the 2nd operational amplifier (OPA2) is when receiving the drain electrode of described (M4) pipe, also by resistance (R1) ground connection;

The 3rd operational amplifier (OPA3), the grid of output termination metal-oxide-semiconductor (M7), and being somebody's turn to do the positive input terminal of drain feedback to the 3 operational amplifiers (OPA3) of (M7) pipe, the positive input terminal of the 3rd operational amplifier (OPA3) is through resistance (R2) ground connection, and negative input end meets PNP transistor (Q ₂) emitter, should (Q ₂) all the other two-terminal-groundings of pipe;

Metal-oxide-semiconductor (M5), (M2), both source electrodes meet power vd D, and drain electrode connects the negative input end of described the 3rd operational amplifier (OPA3) after linking to each other, (M5) grid of pipe is received the output terminal of described the 2nd operational amplifier (OPA2), and (M2) grid of pipe then connects the output terminal of described the 1st operational amplifier (OPA1);

Metal-oxide-semiconductor (M8), (M9), the source electrode that is somebody's turn to do (M8) pipe meets power vd D, and drain electrode connects the drain and gate of (M9) pipe simultaneously, is somebody's turn to do the source ground of (M9) pipe;

Metal-oxide-semiconductor (M6), (M10), the source electrode that is somebody's turn to do (M6) pipe meets power vd D, and grid is received the output terminal of described the 2nd operational amplifier (OPA2), the drain electrode of being somebody's turn to do (M6) pipe simultaneously connects the drain electrode of (M10) pipe, form the output terminal Vbg of described reference voltage source, and (M10) grid of pipe links to each other with the grid of described (M9) pipe, but (M10) source ground of pipe;

Metal-oxide-semiconductor (M3), source electrode meets power vd D, and grid connects the output terminal of described the 1st operational amplifier (OPA1), and resistance (R3) and the mid point (R4) that is serially connected between described output terminal Vbg and the ground received in the drain electrode of being somebody's turn to do (M3);

Described (R ₀)=8k Ω～12k Ω;

(R ₁) at the described (Q that passes through ₂) the condition that do not change with temperature T substantially of electric current under differentiate obtains to temperature,

$R_1=(\mathrm{\&eta;}-x+\frac{V_{g0}-V_{\mathrm{be}}\left(T_r\right)}{V_{T_r}})\frac{R_0}{\ln n},$

Wherein, V _G0The pn junction diode voltage that extrapolation obtains when being 0K, V _Be(T _r) be in temperature T _rThe time voltage between base stage and the emitter, x is that the temperature that flows through transistor current relies on parameter, η is temperature independent and relevant with technology parameter, value between 3.6 to 4, V _T=kT/q is a thermal voltage, and k is a Boltzmann constant (1.38 * 10 ^-23J/K), q is an electron charge (1.6 * 10 ^-19C), T is an absolute temperature, and n is described transistor (Q ₀) and (Q ₁) the ratio of emitter area;

(R ₂) at the output current T of described reference voltage source _BgIn the logarithmic term of temperature be to obtain under zero the condition,

$R_2=\frac{\mathrm{\&eta;}}{\mathrm{\&eta;}-1}{R}_1,$

(R3), (R4) linear compensation relation and desired output reference voltage as requested obtain,

$R_4=\frac{(V_{g0}-V_{\mathrm{be}}\left(T_r\right))V_{\mathrm{bg}}}{V_{T_r}{V}_{g0}\ln n}{R}_0,$

$R_3=\frac{V_{\mathrm{bg}}}{V_{g0}}\frac{R_1{R}_2}{R_2-R_1}-R_4.$

2. the high-temperature stability reference voltage source that 1V power supply non-linear according to claim 1 is corrected is characterized in that described operational amplifier (OPA1), (OPA2) reach (OPA3) employing the two poles of the earth accordion structure.

3. the high-temperature stability reference voltage source that 1V power supply non-linear according to claim 1 and 2 is corrected is characterized in that described operational amplifier (OPA1), (OPA2) and input end (OPA3) insert one and start and biasing circuit, and this circuit contains:

The 1st parallel branch is formed by metal-oxide-semiconductor (M101), resistance (R6), metal-oxide-semiconductor (M102) serial connection, wherein, and the drain electrode of a termination of resistance (R6) described (M101) pipe, the drain electrode of another termination (M102) pipe;

The 2nd parallel branch is formed by metal-oxide-semiconductor (M201), (M202) serial connection, should link to each other with the drain electrode of (M202) pipe by (M201) pipe;

The source electrode of described (M101) pipe, (M201) pipe meets power vd D, and (M102) pipe, (M202) pipe source ground, the grid that is somebody's turn to do (M102) pipe simultaneously connects and enables control signal En, drain and gate that should (M202) pipe output vbiasn that links to each other, should (M101) pipe, the grid of (M201) pipe links to each other and receive the drain electrode of described (M101) pipe after constitute second and be output as vbiasp jointly.

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