CN103245435B - For temperature calibration instrument and the method for CMOS temperature transmitter - Google Patents

Abstract

The invention discloses a kind of temperature calibration instrument for CMOS temperature transmitter and method.This calibrating installation comprises CMOS temperature-sensitive circuit, data processing unit, slope register, intercept register, temperature value registers and standard thermometer.Temperature calibration instrument for CMOS temperature transmitter of the present invention and method, do not need impressed voltage source, only utilize two temperature test points just can temperature sensor is calibrated to ± precision of 0.2 DEG C, calibration speed is fast, do not increase peripheral circuit, therefore greatly reduce testing cost.

Description

For temperature calibration instrument and the method for CMOS temperature transmitter

Technical field

The present invention relates to CMOS temperature transmitter, more specifically, is a kind of temperature calibration instrument for CMOS temperature transmitter and method.

Background technology

Integrated CMOS temperature sensor utilizes the parasitic PNP triode in CMOS technology to produce V as temperature-sensing element _bEwith Δ V _bEtwo with the voltage signal of temperature correlation, wherein V _bEvoltage raises with temperature and reduces, Δ V _bEvoltage raises with temperature and increases.The readout of temperature can with a variable α Δ V relevant to 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 _bE-2mV/ DEG C is about, Δ V at 25 DEG C of temperatures coefficient _bEthe electric current ratio of two PNP triodes is depended on, if adopt 1 at the temperatures coefficient of 25 DEG C; 5 electric current ratio, then Δ V _bEbe about 0.14mV/ DEG C at the temperature coefficient of 25 DEG C, therefore can obtain the V irrelevant with temperature variation at-55 DEG C ~ 125 DEG C during α=14 _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)

Temperature readout can be obtained by following linear equation:

T _oUT=A. μ+B (formula 3)

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

Process drift and chip package thereof can cause V _bEvariation with temperature rate changes, thus causes temperature readout T _oUTvariation with temperature slope departs from ideal value 1.Fig. 2 shows temperature readout T in-55 DEG C ~ 125 DEG C temperature ranges _oUTvariation with 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.In Fig. 2, dash area represents T _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 _oUTthe problem that variation with temperature slope departs from ideal value and causes precision to reduce, the present invention proposes a kind of temperature calibration instrument for CMOS temperature transmitter and method.This device comprises CMOS temperature-sensitive circuit, data processing unit, slope register, intercept register, temperature value registers and standard thermometer, wherein:

This CMOS temperature-sensitive circuit is connected with this data processing unit, and it has a temperature and characterizes predetermined variable, and output temperature readout, this temperature readout and this predetermined temperature token state are predetermined linear relation;

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

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

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

This temperature value registers is connected with this data processing unit, for being deposited with two temperature readouts of this CMOS temperature-sensitive circuit corresponding to these two points for measuring temperature;

This data processing unit is used for exporting and this predetermined linear relation according to these two actual temperatures, determine two corresponding temperature token state output valves, and according to these two points for measuring temperature and these two temperature token state output valves, carry out actual line sexual intercourse matching, determine this slope calibration value and this intercept calibration value.

Preferably, described data processing unit is microprocessor.

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

S100, determine that the temperature of this CMOS temperature transmitter characterizes the predetermined linear relation of predetermined variable and temperature readout variable, this predetermined linear relation comprises slope default value and intercept default value;

S200, under two points for measuring temperature, utilizes two temperature readouts of CMOS temperature transmitter, and according to this predetermined linear relation, determines two corresponding temperature token state output valves;

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

Preferably, described predetermined linear pass is:

T _OUT＝A.μ+B；

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

Preferably, described two temperature token state 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 thermometer value indicative 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 _cfor described slope calibration value, B _cfor described intercept calibration value, T _w1, T _w2for described two points for measuring temperature.

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

Accompanying drawing explanation

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

Fig. 2 is the schematic diagram of the linear relationship skew showing CMOS temperature transmitter output signal and readout;

Fig. 3 is the composition schematic diagram of the temperature calibration instrument for CMOS temperature transmitter of the present invention;

Fig. 4 is the flow process signal intention utilizing the temperature calibration instrument in Fig. 3 to carry out the method for temperature correction.

Embodiment

Below in conjunction with the drawings and specific embodiments, the composition structure of the temperature calibration instrument for CMOS temperature transmitter of the present invention and method or step and principle of work are described in detail.

As shown in Figure 3, for the composition schematic diagram of the temperature calibration instrument for CMOS temperature transmitter 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 thermometer 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 output temperature readout, this temperature readout and this predetermined temperature token state are predetermined linear relation.As mentioned above, this temperature characterize predetermined variable be one with the voltage signal V of two in 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 conventional integrated CMOS temperature-sensitive circuit formed as temperature-sensing element by the parasitic PNP triode in CMOS technology.Further, 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, for depositing slope default value or slope calibration value.Intercept register 130 is connected with data processing unit 140, for depositing intercept default value or intercept calibration value.

As mentioned above, above-mentioned predetermined linear relation (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 slope register 120 and intercept register 130.Further, 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 thermometer 160 is connected with data processing unit 140, for determining two points for measuring temperature.Standard thermometer 160 can adopt conventional standard thermometer, accurately to determine point for measuring temperature.In the invention, need at least to two point for measuring temperature T _w1, T _w2determine, to carry out linear relationship calibration.

Temperature value registers 150 is connected with data processing unit 140, for being deposited with two temperature readouts T1, T2 of CMOS temperature-sensitive circuit 110 corresponding to these two points for measuring temperature.At two actual point for measuring temperature T _w1, T _w2under, 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 temperature value registers 150 for follow-up calibration process.

This data processing unit 140, for exporting T1, T2 and this predetermined linear relation (formula 3) according to two actual temperatures, determines two corresponding temperature token state output valve μ ₁, μ ₂, and according to two point for measuring temperature T _w1, T _w2with two temperature token state output valve μ ₁, μ ₂, carry out actual line sexual intercourse matching, determine this slope calibration value and this intercept calibration value.Thus, the calibration to linear relationship is completed.Concrete data handling procedure will hereafter be described in more detail.

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

In the step s 100, determine that the temperature of this CMOS temperature transmitter characterizes the predetermined linear relation of predetermined variable and temperature readout variable, this predetermined linear relation comprises slope default value and intercept default value.

As shown in above-mentioned formula 3, predetermined linear pass is:

T _OUT＝A.μ+B；

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

As can be seen from above, T _oUTdetermined by A, B with the predetermined linear relation of μ, A, B value can be arbitrary default value, but convenient for calibrating, and slope default value and intercept default value can be set as circuit simulation value.As mentioned above, slope default value and intercept default value can be deposited with in slope register 120 and intercept register 130 respectively.

S200, under two points for measuring temperature, utilizes two temperature readouts of CMOS temperature transmitter, and according to this predetermined linear relation, determines two corresponding temperature token state 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 transmitter, such as, T shown in Fig. 2 _w1=-55 DEG C and T _w2=125 DEG C.Further, according to the slope default value A in relation predetermined linear in formula 3 and intercept default value B, two temperature token state output valves under these two points for measuring temperature are calculated.

Two temperature token state output valves are specifically calculated as follows:

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

Thus draw:

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

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

In step S300, according to two point for measuring temperature T _w1, T _w2with these two temperature token state output valve μ ₁, μ ₂, carry out actual line sexual intercourse matching, determine slope calibration value and intercept calibration value.

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

First, actual line sexual intercourse matching is carried out to each point for measuring temperature and the output of corresponding temperature token state:

$\begin{array}{c}{T}_{W1}=A_c{\mathrm{\μ}}_1+B\\ T_{W2}=A_c{\mathrm{\μ}}_2+B\end{array};$ (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 _cfor slope calibration value, B _cfor intercept calibration value, T _w1, T _w2for described two points for measuring temperature.

Then, the slope calibration value A that can will calculate _cwith intercept calibration value B _cinsert slope register 120 and intercept register 130 respectively, thus complete the calibration to CMOS temperature transmitter.

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

Claims (6)

1. for a temperature calibration instrument for CMOS temperature transmitter, it is characterized in that, comprise CMOS temperature-sensitive circuit, data processing unit, slope register, intercept register, temperature value registers and standard thermometer, wherein:

This CMOS temperature-sensitive circuit is connected with this data processing unit, and it has a temperature and characterizes predetermined variable, and output temperature readout, it is predetermined linear relation that this temperature readout and this temperature characterize predetermined variable;

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

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

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

This temperature value registers is connected with this data processing unit, for being deposited with two temperature readouts of this CMOS temperature-sensitive circuit corresponding to these two points for measuring temperature, and described two temperature readouts and described two points for measuring temperature one_to_one corresponding respectively;

This data processing unit is used for according to these two temperature readouts and this predetermined linear relation, determine two corresponding temperature token state output valves, and according to these two points for measuring temperature and these two temperature token state output valves, carry out actual line sexual intercourse matching, determine this slope calibration value and this intercept calibration value.

2. the temperature calibration instrument for CMOS temperature transmitter according to claim 1, is characterized in that, described data processing unit is microprocessor.

3., for a temperature correction method for CMOS temperature transmitter, it is characterized in that, the method comprises the steps:

S100, determine that the temperature of this CMOS temperature transmitter characterizes the predetermined linear relation of predetermined variable and temperature readout variable, this predetermined linear relation comprises slope default value and intercept default value;

S200, under two points for measuring temperature, utilizes two temperature readouts of CMOS temperature transmitter, and according to this predetermined linear relation, determines two corresponding temperature token state output valves;

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

4. the temperature correction method for CMOS temperature transmitter according to claim 3, is characterized in that, described predetermined linear pass is:

T _OUT＝A.μ+B；

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

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

μ ₁＝(T1-B)/A

；

μ ₂＝(T2-B)/A

Wherein, μ ₁, μ ₂be respectively described two thermometer value indicative output valves, T1, T2 are respectively two temperature readouts of this CMOS temperature transmitter under described two points for measuring temperature.

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

A _c＝(T _W2-T _W1)/(μ ₂-μ ₁)

；

B _c＝-(Aμ ₂-T _W2)

Wherein, A _cfor described slope calibration value, B _cfor described intercept calibration value, T _w1, T _w2for described two points for measuring temperature.