CN101833351A - Low-voltage and extra-low-power consumption voltage reference source - Google Patents

Abstract

The invention belongs to the technical field of integrated circuits and relates a novel low-voltage and extra-low-power consumption voltage reference source. The low-voltage and extra-low-power consumption voltage reference source comprises a positive temperature coefficient voltage generating circuit M1, a positive temperature coefficient voltage generating circuit M2, a negative temperature coefficient voltage generating circuit M3, an offset generating circuit, switch MOS (Metal Oxide Semiconductor) pipes, a capacitor and a two-phase non-overlapping clock (11). The invention realizes positive temperature coefficient voltage by adopting serial connection of MOS pipes working in a subthreshold value, realizes negative temperature coefficient voltage by adopting the temperature characteristics of MOS threshold voltage and realizes reference voltage which is irrelevant to temperature by weight addition of two voltage bands with different temperature coefficients through a switch capacitive circuit. The circuit structure of the low-voltage and extra-low-power consumption voltage reference source is suitable for working under the condition of low-voltage and extra-low-power consumption, the chip occupation area is small, and the cost is low.

Description

A kind of low-voltage and extra-low-power consumption voltage reference source

Technical field

The invention belongs to technical field of integrated circuits, be specifically related to a kind of novel low pressure, extremely low power dissipation voltage-reference.

Background technology

Voltage-reference is a kind of basic module that is widely used in simulation and digital display circuit, and its effect provides a reference voltage accurately.The reference voltage value that traditional band-gap reference circuit produces is about 1.2V, and this just needs supply voltage to be higher than this value.The handheld electronic product develop rapidly and huge market impels the circuit of low-voltage and low-power dissipation to be subjected to widely paying attention to.Therefore, develop and to be necessary at operation at low power supply voltage and voltage-reference that have extremely low power dissipation.

In the prior art, have document proposed a kind of can be at the voltage-reference of the following voltage power supply of 1-V, as shown in Figure 1.The basic design philosophy of this voltage-reference is: produce the voltage (V that is directly proportional with temperature at first respectively _PTAT) and one with the temperature voltage (V that is inversely proportional to _CTAT), again two voltages are utilized electric resistance partial pressure principle cum rights heavy phase to add.Yet this circuit is not suitable for extremely low power dissipation (less than the 1uW power consumption) occasion.At first, because V _PTATThe electric current that depends on be directly proportional with temperature (PTAT) of generation pour into resistance R 2, if need to reduce current value, it is too big that the value of R2 can become, so that be difficult on chip integrated.Secondly, V _PTATAnd V _CTATAddition be to adopt resistance R 3, R4 to realize because V _PTATAnd V _CTATCan have difference, this can cause certain electric current to flow through R3 and R4, and in order not influence precision, the electric current that flows through R3 and R4 must be much smaller than bias current.In the application scenario of extremely low power dissipation, be similar to analysis for the R2 value, the value of R3 and R4 equally can be very big and influence integrated on chip.

Under such background, develop and novel super low-power consumption voltage reference source structure, when realizing low-power consumption, can not increase the cost that circuit is made again, have certain realistic meaning.

Summary of the invention

The object of the present invention is to provide a kind of novel voltage-reference, can under voltage, work and consume extremely low power consumption less than 1V.

The principle of work of reference source circuit proposed by the invention, be to adopt the metal-oxide-semiconductor that is operated in subthreshold value to be connected in series to realize the voltage of positive temperature coefficient (PTC), adopt the voltage of the temperature characterisitic realization negative temperature coefficient of MOS threshold voltage, by the voltage belt weight addition of switched-capacitor circuit, thereby realized temperature independent reference voltage with two different temperature coefficients.

Low-voltage and extra-low-power consumption voltage reference source provided by the present invention, by positive temperature coefficient (PTC) voltage generation circuit M1 and M2 (1), negative temperature coefficient voltage generation circuit M3 (2), offset generating circuit (3), switch MOS pipe (4,5,6,7), electric capacity (8,9,10) and the clock of the non-overlapping of two-phase (11) constitute, its circuit is as shown in Figure 2.

In low-voltage and extra-low-power consumption voltage reference source provided by the present invention, M1, M2 (1) are positive temperature coefficient (PTC) voltage (V _PTAT) producing circuit, M3 (2) is negative temperature coefficient voltage (V _CTAT) producing circuit, they provide bias current by bias current generating circuit (3).The output of M1 and M2 (1) meets switch MOS pipe M _S1(4) a end; Switch MOS pipe M _S1(4) another termination capacitor C ₁(8); The output of negative temperature coefficient voltage generation circuit M3 (2) meets switch MOS pipe M _S4(7) a end; M _S4(7) another termination capacitor C ₂(10); Switch MOS pipe M _S1, M _S2, M _S3, M _S4(4,5,6,7) are connected in series successively; Capacitor C _o(10) be connected on switch MOS pipe M _S2, M _S3The junction of (5,6); Switch MOS pipe M _S1, M _S4Grid by the non-overlapping clock of two-phase Φ ₁, Φ ₂(11) one in drive mutually; Switch MOS pipe M _S2, M _S3Grid by the non-overlapping clock of two-phase Φ ₁, Φ ₂(11) another in drives mutually; Voltage reference output (12) is positioned at switch MOS pipe M _S2, M _S3The junction of (5,6).

Switched-capacitor circuit (4-10) is with V _PTATWith V _CTATThe cum rights heavy phase adds, and promptly obtains temperature independent reference voltage.

Low-voltage and extra-low-power consumption voltage reference source provided by the present invention, circuit structure are adapted at working under low pressure, the extremely low power dissipation condition, and chip occupying area is little, and cost is low.

Description of drawings

Fig. 1 is a kind of existing low pressure reference source circuit figure.

Fig. 2 is the low-voltage and extra-low-power consumption voltage reference source circuit diagram that the present invention proposes, and wherein 1 is V _PTATProduce circuit, 2 is V _CTATProduce circuit, 3 is bias current generating circuit, and 4,5,6,7 is the metal-oxide-semiconductor switch in the switched-capacitor circuit, and 8,9,10 is the electric capacity in the switched-capacitor circuit, 11 clocks that do not overlap for two-phase, and 12 is the output of voltage reference.

Specific embodiments

Below in conjunction with specific embodiment, the present invention is further elaborated.Embodiment only is used for the present invention is done explanation rather than limitation of the present invention.

Embodiment:

Present embodiment 2 further describes the present invention in conjunction with the accompanying drawings.

As shown in Figure 2, the low-voltage and extra-low-power consumption voltage reference source of present embodiment, by positive temperature coefficient (PTC) voltage generation circuit M1 and M2 (1), negative temperature coefficient voltage generation circuit M3 (2), offset generating circuit (3), switch MOS pipe (4,5,6,7), electric capacity (8,9,10) and the clock of the non-overlapping of two-phase (11) constitute, bias current generating circuit (3) provides bias current for M1, M2 (1) and M3 (2).The output of M1 and M2 (1) meets switch MOS pipe M _S1(4) a end; Switch MOS pipe M _S1(4) another termination capacitor C ₁(8); The output of negative temperature coefficient voltage generation circuit M3 (2) meets switch MOS pipe M _S4(7) a end; M _S4(7) another termination capacitor C ₂(10); Switch MOS pipe M _S1, M _S2, M _S3, M _S4(4,5,6,7) are connected in series successively; Capacitor C _o(10) be connected on switch MOS pipe M _S2, M _S3The junction of (5,6); Switch MOS pipe M _S1, M _S4Grid by the non-overlapping clock of two-phase Φ ₁, Φ ₂(11) one in drive mutually; Switch MOS pipe M _S2, M _S3Grid by the non-overlapping clock of two-phase Φ ₁, Φ ₂(11) another in drives mutually; Voltage reference output (12) is positioned at switch MOS pipe M _S2, M _S3The junction of (5,6).

M1, M2 (1) all are in sub-threshold region, and the bias current of supposing them is I _B, by the metal-oxide-semiconductor current expression of sub-threshold region as can be known,

$I_B=I_{D0}\frac{W}{L}\exp \left(\frac{{\mathrm{<figure-callout\; id="1"\; label="V\; GS"\; filenames="H2009100476055E0000012.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{GS}}}{\mathrm{nkt}/q}\right)=I_{D0}m\frac{W}{L}\exp \left(\frac{{\mathrm{<figure-callout\; id="2"\; label="V\; GS"\; filenames="H2009100476055E0000012.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{GS}}}{\mathrm{nkt}/q}\right)---\left(1\right)$

I wherein _D0, nkt/q is a constant,

Be the breadth length ratio of M1,

Be the breadth length ratio of M2, m is the constant greater than 1.

By (1) Shi Kede,

V _PTAT＝V _GS1-V _GS2＝nkt/qln(m) (2)

By (2) formula as can be known, the metal-oxide-semiconductor of two different breadth length ratios of employing is connected in series and can obtains a voltage that is directly proportional with temperature.

M3 (2) is in sub-threshold region equally, because the threshold voltage of metal-oxide-semiconductor is inversely proportional to temperature, because

V _CTAT＝V _GS3＝V _TH3+V _OV (3)

The former M3 (2) that can get must grid voltage be V _CTATBe inversely proportional to temperature equally.V in the formula (3) _OVOverdrive voltage for M3.

Obtaining V _PTATAnd V _CTATAfterwards, adder circuit proposed by the invention uses switching capacity to realize.Φ ₁, Φ ₂(11) will there be Φ in the clock that does not overlap for two-phase so this moment ₁Be high level and Φ ₂Be two kinds of situations of high level.

1) works as Φ ₁Φ during for high level ₂During for low level, MS1 and MS4 conducting, C at this moment ₁And C ₂On electric charge be respectively C ₁V _PTATAnd C ₂V _CTAT

2) work as Φ ₂Φ during for high level ₁During for low level, MS2 and MS3 conducting, C at this moment ₁, C ₂And C _oOn the electric charge voltage that will reassign to the three will equate.

Under equilibrium state, the total amount of electric charge under two kinds of situations should equate, promptly

C ₁V _PTAT+C ₂V _CTAT+C _oV _ref＝(C ₁+C ₂+C _o)V _ref (4)

Thereby can obtain:

$V_{\mathrm{ref}}=\frac{C_1}{{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009100476055E0000012.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_2}{V}_{\mathrm{PTAT}}+\frac{C_2}{{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009100476055E0000012.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_2}{V}_{\mathrm{CTAT}}---\left(5\right)$

Select appropriate C ₁And C ₂Value promptly can obtain temperature independent reference voltage V _Ref

Claims (6)

1. low-voltage and extra-low-power consumption voltage reference source, it is characterized in that it is by positive temperature coefficient (PTC) voltage generation circuit M1 and M2 (1), negative temperature coefficient voltage generation circuit M3 (2), offset generating circuit (3), switch MOS pipe (4,5,6,7), electric capacity (8,9,10) and the clock of the non-overlapping of two-phase (11) constitute.

2. low-voltage and extra-low-power consumption voltage reference source according to claim 1, it is characterized in that adopting the metal-oxide-semiconductor that is operated in subthreshold value to be connected in series and realize positive temperature coefficient (PTC) voltage, adopt the temperature characterisitic of MOS threshold voltage to realize negative temperature coefficient voltage, by the voltage belt weight addition of switched-capacitor circuit, realize temperature independent reference voltage with two different temperature coefficients.

3. low-voltage and extra-low-power consumption voltage reference source according to claim 1 is characterized in that described offset generating circuit (3) provides bias current for positive temperature coefficient (PTC) voltage generation circuit M1 and M2 (1) and negative temperature coefficient voltage generation circuit M3 (2).

4. low-voltage and extra-low-power consumption voltage reference source according to claim 1 is characterized in that the output of positive temperature coefficient (PTC) voltage generation circuit M1 and M2 (1) meets switch MOS pipe M _S1(4) a end; Switch MOS pipe M _S1(4) another termination capacitor C ₁(8); The output of negative temperature coefficient voltage generation circuit M3 (2) meets switch MOS pipe M _S4(7) a end; M _S4(7) another termination capacitor C ₂(10); Switch MOS pipe M _S1, M _S2, M _S3, M _S4(4,5,6,7) are connected in series successively; Capacitor C _o(10) be connected on switch MOS pipe M _S2, M _S3The junction of (5,6).

5. low-voltage and extra-low-power consumption voltage reference source according to claim 1 is characterized in that switch MOS pipe M _S1, M _S4Grid by the non-overlapping clock of two-phase Φ ₁, Φ ₂(11) one in drive mutually, switch MOS pipe M _S2, M _S3Grid by the non-overlapping clock of two-phase Φ ₁, Φ ₂(11) another in drives mutually.

6. low-voltage and extra-low-power consumption voltage reference source according to claim 1 is characterized in that voltage reference output (12) is positioned at switch MOS pipe M _S2, M _S3The junction of (5,6).

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