CN103245435A - Temperature calibration device and method for CMOS (Complementary Metal Oxide Semiconductor) temperature sensor - Google Patents

Abstract

The invention discloses a temperature calibration device and method for a CMOS (Complementary Metal Oxide Semiconductor) temperature sensor. The calibration device comprises a CMOS temperature sensing circuit, a data processing unit, a slope register, an intercept register, a temperature value register and a standard thermometer. According to the temperature calibration device and method for the CMOS temperature sensor, a voltage source is not required to be externally applied, the temperature sensor can be calibrated to the accuracy of +/-0.2 DEG C by only using two temperature testing points, the calibration speed is high, and no peripheral circuit is added, so that the testing cost is greatly reduced.

Description

The temperature correction device and method that is used for the CMOS temperature sensor

Technical field

The present invention relates to the CMOS temperature sensor, more specifically, is a kind of temperature correction device and method for the CMOS temperature sensor.

Background technology

The integrated CMOS temperature sensor utilizes the parasitic PNP triode in the CMOS technology to produce V as temperature-sensing element _BEWith Δ V _BETwo voltage signals with temperature correlation, wherein V _BEVoltage raises with temperature and reduces Δ V _BEVoltage raises with temperature and increases.The readout of temperature can be with a variable α Δ V relevant with temperature linearity _BE(V _PTAT) a relative temperature independent constant α Δ V _BE+ V _BE(V _REF) proportionate relationship try to achieve, specifically as shown in Figure 1.

V _BEBe about-2mV/ ℃ Δ V at 25 ℃ of temperatures coefficient _BEDepend on the current ratio of two PNP triodes at 25 ℃ temperatures coefficient, if adopt 1; 5 current ratios, then Δ V _BEAt the about 0.14mV/ of 25 ℃ temperature coefficient ℃, so α=14 o'clock can obtain the V irrelevant with temperature variation at-55 ℃～125 ℃ _REF, wherein,

V _REF=α Δ V _BE+ V _BE(formula 1)

With ratio value μ as variable, wherein,

$\mathrm{\μ}=\frac{{\mathrm{\α\ΔV}}_{\mathrm{BE}}}{{\mathrm{\α\ΔV}}_{\mathrm{BE}}+V_{\mathrm{BE}}};$ (formula 2)

Can obtain the temperature readout by following linear equation:

T _OUT=A. μ+B (formula 3)

Wherein A ≈ 680, B ≈ 280, T _OUTIt is the temperature readout.

Process drift and chip encapsulation thereof can cause V _BEChange with the variation of temperature rate, thereby cause temperature readout T _OUTDepart from ideal value 1 with the variation of temperature slope.Fig. 2 shows temperature readout T in-55 ℃～125 ℃ temperature ranges _OUTWith variation of temperature rate and V _BEVary with temperature the relation of rate.Work as V _BEWhen the absolute value of temperature variant straight slope is less than normal, T _OUTTemperature variant straight slope is bigger than normal; Work as V _BEWhen the absolute value of temperature variant straight slope is bigger than normal, T _OUTTemperature variant straight slope is less than normal.Dash area is represented T among Fig. 2 _OUTVary with temperature the scope of straight slope, as seen from the figure, the deviation of straight slope can reduce temperature sensing actuator temperature readout T _OUTPrecision.

Summary of the invention

In order to solve temperature readout T _OUTDepart from the problem that ideal value causes precision to reduce with the variation of temperature slope, the present invention proposes a kind of temperature correction device and method for the CMOS temperature sensor.This device comprises CMOS temperature-sensitive circuit, data processing unit, slope register, intercept register, temperature value registers and standard thermo detector, wherein:

This CMOS temperature-sensitive circuit is connected with this data processing unit, and it has a temperature and characterizes predetermined variable, and the output temperature readout, and this temperature readout and this predetermined temperature sign amount are the preset lines sexual intercourse;

This slope register is connected with this data processing unit, is used for depositing slope default value or slope calibration value;

This intercept register is connected with this data processing unit, is used for depositing intercept default value or intercept calibration value;

This standard thermo detector is connected with this data processing unit, is used for determining two points for measuring temperature;

This temperature value registers is connected with this data processing unit, for two temperature readouts of this CMOS temperature-sensitive circuit that is deposited with these two point for measuring temperature correspondences;

This data processing unit is used for according to this two actual temperature outputs and this preset lines sexual intercourse, determine two corresponding temperature sign amount output valves, and according to these two points for measuring temperature and these two temperature sign amount output valves, carry out actual line sexual intercourse match, determine this slope calibration value and this intercept calibration value.

Preferably, described data processing unit is microprocessor.

Temperature correction method for the CMOS temperature sensor of the present invention comprises the steps:

S100 determines that the temperature of this CMOS temperature sensor characterizes the preset lines sexual intercourse of predetermined variable and temperature readout variable, and this preset lines sexual intercourse comprises slope default value and intercept default value;

S200 under two points for measuring temperature, utilizes two temperature readouts of CMOS temperature sensor, and according to this preset lines sexual intercourse, determines two corresponding temperature sign amount output valves;

S300 according to these two points for measuring temperature and these two temperature sign amount output valves, carries out actual line sexual intercourse match, determines slope calibration value and intercept calibration value.

Preferably, described preset lines sexual intercourse is:

T _OUT＝A.μ+B；

Wherein, T _OUTBe temperature readout variable, μ is that temperature characterizes predetermined variable, and A is the slope default value, and B is the intercept default value.

Preferably, described two temperature sign amount output valves are respectively:

μ $\begin{array}{c}{\mathrm{\μ}}_1=(T1-B)/A\\ {\mathrm{\μ}}_2=(T2-B)/A\end{array};$

Wherein, μ ₁, μ ₂Be respectively described two temperature characterization value output valves, T1, T2 are respectively two temperature readouts under described two points for measuring temperature.

Preferably, described slope calibration value and intercept calibration value are:

$\begin{array}{c}{A}_c=(T_{W2}-T_{W1})/({\mathrm{\μ}}_2-{\mathrm{\μ}}_1)\\ B_c=-({\mathrm{A\μ}}_2-T_{W2})\end{array};$

Wherein, A _CBe described slope calibration value, B _CBe described intercept calibration value, T _W1, T _W2Be described two points for measuring temperature.

Temperature correction device and method for the CMOS temperature sensor of the present invention, do not need the impressed voltage source, only utilize two temperature test points just can in-55 ℃～125 ℃ temperature ranges, temperature sensor be calibrated to ± 0.2 ℃ precision, calibration speed is fast, do not increase peripheral circuit, therefore greatly reduce testing cost.

Description of drawings

Fig. 1 is the linear relationship synoptic diagram of output signal and the temperature of temperature-sensing element;

Fig. 2 is the synoptic diagram that shows the linear relationship skew of CMOS temperature sensor output signal and readout;

Fig. 3 is the composition synoptic diagram of the temperature correction device for the CMOS temperature sensor of the present invention;

Fig. 4 utilizes temperature correction device among Fig. 3 to carry out the flow process signal intention of the method for temperature correction.

Embodiment

Below in conjunction with the drawings and specific embodiments, the composition structure of the temperature correction device and method for the CMOS temperature sensor of the present invention or step and principle of work are elaborated.

As shown in Figure 3, be the composition synoptic diagram of the temperature correction device for the CMOS temperature sensor of the present invention, it comprises CMOS temperature-sensitive circuit 110, data processing unit 140, slope register 120, intercept register 130, temperature value registers 150 and standard thermo detector 160.

More specifically, CMOS temperature-sensitive circuit 110 is connected with data processing unit 140, and it has a temperature and characterizes predetermined variable, and the output temperature readout, and this temperature readout and this predetermined temperature sign amount are the preset lines sexual intercourse.As mentioned above, this temperature characterize predetermined variable be one with interior two the voltage signal V of CMOS temperature-sensitive circuit 110 _BEWith Δ V _BERelevant variable μ (as shown in Equation 2), and this variable and temperature readout linear (as shown in Equation 3).

In this embodiment, CMOS temperature-sensitive circuit 110 can be the integrated CMOS temperature-sensitive circuit that the conventional parasitic PNP triode by in the CMOS technology forms as temperature-sensing element.And data processing unit 140 can be any treating apparatus that can carry out linear relationship computing and output, comprises central processing unit, digital signal processor, special-purpose programmable logic chip etc.In this embodiment, data processing unit 140 is microprocessor.

Slope register 120 is connected with data processing unit 140, is used for depositing slope default value or slope calibration value.Intercept register 130 is connected with data processing unit 140, is used for depositing intercept default value or intercept calibration value.

As mentioned above, above-mentioned preset lines sexual intercourse (formula 3) is determined by slope default value A and intercept default value B, before calibrating, this slope default value A and intercept default value B can be pre-deposited in corresponding the slope register 120 and intercept register 130.And after calibrating, slope register 120 can be used for depositing the slope calibration value through calibration, and intercept register 130 can be used for depositing the intercept calibration value through calibration.

Standard thermo detector 160 is connected with data processing unit 140, is used for determining two points for measuring temperature.Standard thermo detector 160 can adopt conventional standard thermometer, accurately to determine point for measuring temperature.In this invention, need at least to two point for measuring temperature T _W1, T _W2Determine, to carry out the linear relationship calibration.

Temperature value registers 150 is connected with data processing unit 140, for two temperature readout T1, T2 of the CMOS temperature-sensitive circuit 110 that is deposited with these two point for measuring temperature correspondences.At two actual point for measuring temperature T _W1, T _W2Down, CMOS temperature-sensitive circuit 110 calculates via data processing unit 140, according to linear relationship, can produce two temperature readouts, and these two temperature readouts can be deposited with in the temperature value registers 150 to be used for follow-up calibration process.

This data processing unit 140 is used for determining two corresponding temperature sign amount output valve μ according to two actual temperature output T1, T2 and this preset lines sexual intercourse (formula 3) ₁, μ ₂, and according to two point for measuring temperature T _W1, T _W2With two temperature sign amount output valve μ ₁, μ ₂, carry out actual line sexual intercourse match, determine this slope calibration value and this intercept calibration value.Thus, finish calibration to linear relationship.Concrete data handling procedure will be described in more detail hereinafter.

Below describe utilizing this calibrating installation to carry out Calibration Method.As shown in Figure 4, be the process flow diagram of this method, this method comprises step S100-S400 generally.Below in conjunction with Fig. 3,4, each step is specifically described.

In step S100, determine that the temperature of this CMOS temperature sensor characterizes the preset lines sexual intercourse of predetermined variable and temperature readout variable, this preset lines sexual intercourse comprises slope default value and intercept default value.

Shown in above-mentioned formula 3, the preset lines sexual intercourse is:

T _OUT＝A.μ+B；

Wherein, T _OUTBe temperature readout variable, μ is that temperature characterizes predetermined variable, and A is the slope default value, and B is the intercept default value.

From as can be seen last, T _OUTWith the preset lines sexual intercourse of μ by A, B determines, A, B value can be default values arbitrarily, but for calibration conveniently, slope default value and intercept default value can be set at the circuit simulation value.As mentioned above, slope default value and intercept default value can be deposited with respectively in slope register 120 and the intercept register 130.

S200 under two points for measuring temperature, utilizes two temperature readouts of CMOS temperature sensor, and according to this preset lines sexual intercourse, determines two corresponding temperature sign amount output valves.

These two point for measuring temperature T _W1, T _W2Can be any two temperature values in the effective output temperature of CMOS temperature sensor, for example T shown in Fig. 2 _W1=-55 ℃ and T _W2=125 ℃.And, according to the slope default value A in the preset lines sexual intercourse in the formula 3 and intercept default value B, calculate two temperature sign amount output valves under these two points for measuring temperature.

Two temperature sign amount output valves specifically are calculated as follows:

$\begin{array}{c}T1={\mathrm{A\μ}}_1+B\\ T2={\mathrm{A\μ}}_2+B\end{array};$ (formula 4)

Thereby draw:

μ $\begin{array}{c}{\mathrm{\μ}}_1=(T1-B)/A\\ {\mathrm{\μ}}_2=(T2-B)/A\end{array};$ (formula 5)

In the formula 4,5, μ ₁, μ ₂Be respectively described two temperature characterization value output valves, T1, T2 are respectively two temperature readouts under described two points for measuring temperature.This calculating can be finished in data processing unit 140.

At step S300, according to two point for measuring temperature T _W1, T _W2With these two temperature sign amount output valve μ ₁, μ ₂, carry out actual line sexual intercourse match, determine slope calibration value and intercept calibration value.

This calculating can be finished in data processing unit.Particularly, determine that the computing formula of slope calibration value and intercept calibration value is as follows:

At first, each point for measuring temperature and corresponding temperature sign amount output are carried out actual line sexual intercourse match:

$\begin{array}{c}{T}_{W1}=A_c{\mathrm{\μ}}_1+B\\ T_{W2}=A_c{\mathrm{\μ}}_2+B\end{array};$ (formula 6)

And then draw:

B $\begin{array}{c}{A}_c=(T_{W2}-T_{W1})/({\mathrm{\μ}}_2-{\mathrm{\μ}}_1)\\ B_c=-({\mathrm{A\μ}}_2-T_{W2})\end{array};$ (formula 7)

Wherein, A _CBe slope calibration value, B _CBe intercept calibration value, T _W1, T _W2Be described two points for measuring temperature.

Then, can be with the slope calibration value A that calculates _CWith intercept calibration value B _C Insert slope register 120 and intercept register 130 respectively, thereby finish the calibration to the CMOS temperature sensor.

In sum, calibrating installation of the present invention and method, do not need the impressed voltage source, only need two points for measuring temperature can finish the temperature correction of in certain temperature range (as-55 ℃～125 ℃), thereby the precision of CMOS temperature sensor can be increased to ± 0.2 ℃ precision, and this calibrating installation and method calibration speed are fast, do not increase peripheral circuit, thereby greatly reduce testing cost.

Claims (6)

1. a temperature correction device that is used for the CMOS temperature sensor is characterized in that, comprises CMOS temperature-sensitive circuit, data processing unit, slope register, intercept register, temperature value registers and standard thermo detector, wherein:

This CMOS temperature-sensitive circuit is connected with this data processing unit, and it has a temperature and characterizes predetermined variable, and the output temperature readout, and this temperature readout and this predetermined temperature sign amount are the preset lines sexual intercourse;

This slope register is connected with this data processing unit, is used for depositing slope default value or slope calibration value;

This intercept register is connected with this data processing unit, is used for depositing intercept default value or intercept calibration value;

This standard thermo detector is connected with this data processing unit, is used for determining two points for measuring temperature;

This temperature value registers is connected with this data processing unit, for two temperature readouts of this CMOS temperature-sensitive circuit that is deposited with these two point for measuring temperature correspondences;

This data processing unit is used for according to this two actual temperature outputs and this preset lines sexual intercourse, determine two corresponding temperature sign amount output valves, and according to these two points for measuring temperature and these two temperature sign amount output valves, carry out actual line sexual intercourse match, determine this slope calibration value and this intercept calibration value.

2. the temperature correction device for the CMOS temperature sensor according to claim 1 is characterized in that, described data processing unit is microprocessor.

3. a temperature correction method that is used for the CMOS temperature sensor is characterized in that this method comprises the steps:

S100 determines that the temperature of this CMOS temperature sensor characterizes the preset lines sexual intercourse of predetermined variable and temperature readout variable, and this preset lines sexual intercourse comprises slope default value and intercept default value;

S200 under two points for measuring temperature, utilizes two temperature readouts of CMOS temperature sensor, and according to this preset lines sexual intercourse, determines two corresponding temperature sign amount output valves;

S300 according to these two points for measuring temperature and these two temperature sign amount output valves, carries out actual line sexual intercourse match, determines slope calibration value and intercept calibration value.

4. the temperature correction method for the CMOS temperature sensor according to claim 3 is characterized in that, described preset lines sexual intercourse is:

T _OUT＝A.μ+B；

Wherein, T _OUTBe temperature readout variable, μ is that temperature characterizes predetermined variable, and A is the slope default value, and B is the intercept default value.

5. the temperature correction method for the CMOS temperature sensor according to claim 4 is characterized in that, described two temperature sign amount output valves are respectively:

$\begin{array}{c}{\mathrm{\μ}}_1=(T1-B)/A\\ {\mathrm{\μ}}_2=\left(T2-B\right)/A\end{array};$

Wherein, μ ₁, μ ₂Be respectively described two temperature characterization value output valves, T1, T2 are respectively two temperature readouts of this CMOS temperature sensor under described two points for measuring temperature.

6. the temperature correction method for the CMOS temperature sensor according to claim 5 is characterized in that, described slope calibration value and intercept calibration value are:

$\begin{array}{c}{A}_c=(T_{W2}-T_{W1})/({\mathrm{\μ}}_2-{\mathrm{\μ}}_1)\\ B_c=-({\mathrm{A\μ}}_2-T_{W2})\end{array};$

Wherein, A _CBe described slope calibration value, B _CBe described intercept calibration value, T _W1, T _W2Be described two points for measuring temperature.

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