CN203502144U - Temperature calibration device of integrated CMOS temperature sensor - Google Patents

Abstract

The utility model discloses a temperature calibration device of an integrated CMOS temperature sensor. The device comprises the integrated CMOS temperature sensor, a data processing unit, a slope register, an intercept register, a temperature value register, a decoder and a current adjusting register. The device needs no externally added voltage source, only a temperature test point is needed to improve the temperature calibration precision, the calibration speed is fast, and peripheral circuits are not increased, so the test cost is greatly lowered.

Description

The temperature correction device of integrated CMOS temperature sensor

Technical field

The utility model relates to integrated CMOS temperature sensor, more specifically, is a kind of temperature correction device of integrated CMOS temperature sensor.

Background technology

As shown in Figure 1, integrated CMOS temperature sensor utilizes parasitic PNP triode Q1, Q2 and Q3 in CMOS technique to produce V as temperature-sensing element _bE3with Δ V _bE(V _bE2-V _bE1) two voltage signals with temperature correlation, wherein for generation of V _bE3the electric current of voltage is adjustable current I _tRIM, V _bE3voltage raises and reduces with temperature, has negative temperature characteristic; Δ V _bEthe PNP pipe that voltage is 1:P with two bias currents produces, Δ V _bEwith temperature, raise and increase, there is positive temperature coefficient (PTC).In conjunction with Fig. 2, the readout T of temperature _oUTan available variable α Δ V relevant to temperature linearity _bE(V _pTAT) a relative temperature independent constant V _bE3linear relationship α Δ V _bE+ V _bE3(V _rEF) try to achieve.

Yet, due to process drift and chip package, can cause V _bE3variation with temperature rate and changing, thus cause temperature readout variation with temperature slope to depart from ideal value, thus affect the temperature readout precision of temperature sensor.

Utility model content

In order to solve that CMOS temperature sensing actuator temperature readout variation with temperature slope departs from ideal value and the problem that causes precision to reduce, the utility model proposes a kind of single-point temperature correction device of integrated CMOS temperature sensor.

The temperature correction device of integrated CMOS temperature sensor of the present utility model, comprises integrated CMOS temperature sensor, and this integrated CMOS temperature sensor comprises:

The first temperature sign amount output circuit, for according to the multiple of the first input current and this first input current, exports the first temperature sign amount;

The second temperature sign amount output circuit, be used for according to the second input current, export the second temperature sign amount, this first temperature sign amount and this second temperature sign amount determine a temperature coefficient, and temperature readout and this temperature coefficient of this CMOS temperature sensor are linear;

This temperature correction device also comprises:

Slope register, for depositing the slope default value of this linear relationship;

Intercept register, for depositing the intercept default value of this linear relationship;

Data processing unit, it is connected with this integrated CMOS temperature sensor, this slope register and this intercept register, for according to this linear relationship, determines described temperature readout;

Temperature value registers, it is connected with this data processing unit, for depositing described temperature readout;

Electric current is adjusted register, for depositing electric current, adjusts parameter;

Demoder, it is connected with this CMOS temperature sensor with this electric current adjustment register, decodes, and utilize decoded electric current to adjust parameter this second input current is adjusted for this electric current is adjusted to parameter.

The utility model does not need impressed voltage source, only needs just can in-55 ℃～125 ℃ temperature ranges, the temperature sensor be calibrated to ± precision of 0.2 ℃ of a temperature test point, and calibration speed is fast, does not increase peripheral circuit, so greatly reduces testing cost.

Accompanying drawing explanation

Fig. 1 is the CMOS temperature sensor figure that temperature-sensing element forms;

Fig. 2 is V _bE1, V _bE2, V _bE3with Δ V _bEtemperature characterisitic schematic diagram;

Fig. 3 is the variation schematic diagram that temperature sensing actuator temperature readout varies with temperature slope;

Fig. 4 is that the utility model is for the composition schematic diagram of the temperature correction device of integrated CMOS temperature sensor;

Fig. 5 utilizes temperature correction device to carry out the schematic flow sheet of the method for temperature correction.

Embodiment

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

In conjunction with Fig. 3, V _bE3negative temperature coefficient with I _tRIMchange and change.Work as I _tRIMvoltage V while becoming large _bE3the absolute value of temperature variant slope diminishes, due to α Δ V _bEstraight slope is only relevant to the current ratio of Q1 and Q2, α Δ V in the constant situation of current ratio 1:P _bEstraight slope is constant, so V _rEF=V _bE3+ α Δ V _bEvary with temperature slope on the occasion of, the temperature sensing actuator temperature readout obtaining thus varies with temperature slope and is less than 1.Work as I _tRIMvoltage V while diminishing _bE3it is large that the absolute value of temperature variant slope becomes, due to α Δ V _bEstraight slope is only relevant to the current ratio of Q1 and Q2, α Δ V in the constant situation of current ratio 1:P _bEstraight slope is constant, so V _rEF=V _bE3+ α Δ V _bEvarying with temperature slope is negative value, and the temperature sensing actuator temperature readout obtaining thus varies with temperature slope and is greater than 1.From upper surface analysis, can be by adjusting I _tRIMsize calibration integrated CMOS temperature sensor.

Use further ratio value μ as variable (temperature coefficient), wherein,

$\mathrm{\μ}=\frac{{\mathrm{\α\ΔV}}_{\mathrm{BE}}}{{\mathrm{\α\ΔV}}_{\mathrm{BE}}+V_{\mathrm{BE}}};$ (formula 1)

By following linear equation, can obtain temperature readout:

T _oUT=A. μ+B (formula 2)

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

Based on above principle, the utility model proposes a kind of new temperature correction apparatus and method.As shown in Figure 4, for the composition schematic diagram of the temperature correction device for CMOS temperature sensor of the present utility model, it comprises CMOS temperature sensor 110, data processing unit 160, slope register 140, intercept register 150, temperature value registers 170, demoder 120 and electric current adjustment register 130.

Particularly, CMOS temperature sensor 110 consists of the first temperature sign amount output circuit 111 and the second temperature sign amount output circuit 112.Wherein, the first temperature sign amount output circuit 111, for according to the multiple (PI) of the first input current (I as shown in Figure 1) and this first input current, is exported the first temperature sign amount Δ V _bE; The second temperature sign amount output circuit 112 is for according to the second input current I _tRIM, output the second temperature sign amount V _bE3, as mentioned above, this first temperature sign amount Δ V _bEwith this second temperature sign amount V _bE3determine a temperature coefficient μ (reference formula 1), the temperature readout of this CMOS temperature sensor and this temperature coefficient linear (as shown in Equation 2).

Routinely, the first temperature sign amount output circuit 111 comprises the first triode 1111(Q1 in parallel) and the second triode 1112(Q2), and this first triode 1111(Q1) be connected with the first mirror current source, this second triode 1112(Q2) be connected with the second mirror current source.As shown in the figure, the first mirror current source produces the first input current I, and the second mirror current source produces the multiple PI of the first input current.

The second temperature sign amount output circuit 112 comprises the 3rd triode 1121(Q3), the 3rd triode 1121 is connected with the 3rd mirror current source.The 3rd mirror current source produces adjustable electric current I _tRIM.

Further, CMOS temperature sensor 110 is connected with data processing unit 160, and it has a temperature coefficient μ, and output temperature readout T _oUT, this temperature readout T _oUTwith this temperature coefficient μ be preset lines sexual intercourse (as shown in Equation 2).As mentioned above, this temperature coefficient be one with CMOS temperature sensor 110 in two voltage signal V _bE3with Δ V _bErelevant variable (as shown in Equation 1).

In this embodiment, the first temperature sign amount output circuit 111 in CMOS temperature sensor 110 and the second temperature sign amount output circuit 112 can be the integrated CMOS temperature sensors that the conventional parasitic PNP triode in CMOS technique forms as temperature-sensing element.And data processing unit 160 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 160 is microprocessor.

Slope register 140 is connected with data processing unit 160, for depositing slope default value.Intercept register 150 is connected with data processing unit 160, for depositing intercept default value.

Data processing unit 160 is connected with integrated CMOS temperature sensor 110, slope register 140 and intercept register 150, for according to the linear relationship shown in formula 2, determines temperature readout T _oUT.

Temperature value registers 170 is connected with data processing unit 160, for depositing temperature readout T _oUT.

Electric current is adjusted register 130 and is adjusted parameters C for depositing electric current.And demoder 120 is adjusted register 130 with electric current and is connected with this CMOS temperature sensor, for electric current is adjusted to parameters C, decode, and utilize decoded electric current to adjust parameter to the second input current I _tRIMadjust.The output of demoder 120 is one can adjust I _tRIMthe control signal of size.Large I and the I of this control signal _tRIMlinear.

In this utility model, only need be to single point for measuring temperature T _w1determine, can complete the calibration to temperature sensor.At single actual point for measuring temperature T _w1under, CMOS temperature sensor 110 calculates via data processing unit 160, according to linear relationship, can produce a temperature readout T1, then, electric current is adjusted to parameters C and adjust, thereby temperature readout is moved closer to and equal point for measuring temperature temperature T _w1.

Below the method for utilizing this calibrating installation to calibrate is described.In conjunction with Fig. 4, as mentioned above, the CMOS temperature sensor 110 in this temperature correction circuit consists of the first temperature sign amount output circuit 111 and the second temperature sign amount output circuit 112.Wherein, the first temperature sign amount output circuit 111, for according to the multiple (PI) of the first input current (I as shown in Figure 1) and this first input current, is exported the first temperature sign amount Δ V _bE; The second temperature sign amount output circuit 112 is for according to the second input current I _tRIM, output the second temperature sign amount V _bE3, as mentioned above, this first temperature sign amount Δ V _bEwith this second temperature sign amount V _bE3determine a temperature coefficient μ (reference formula 1), the temperature readout of this CMOS temperature sensor and this temperature coefficient linear (as shown in Equation 2).

And, with reference to figure 4, as mentioned above, in an embodiment of the present utility model, routinely, the first temperature sign amount output circuit 111 comprises the first in parallel triode 1111(Q1) and the second triode 1112(Q2), and this first triode 1111(Q1) be connected with the first mirror current source, this second triode 1112(Q2) be connected with the second mirror current source.As shown in the figure, the first mirror current source produces the first input current I, and the second mirror current source produces the multiple PI of the first input current; The second temperature sign amount output circuit 112 comprises the 3rd triode 1121(Q3), the 3rd triode 1121 is connected with the 3rd mirror current source.The 3rd mirror current source produces adjustable electric current I _tRIM.

As shown in Figure 5, be the particular flow sheet of the method, it comprises step S100-S300 generally.Below in conjunction with Fig. 4,5, each step is specifically described.

In step S100, to determine slope default value A and the intercept default value B of this linear relationship, and determine an electric current adjustment parameter default C, this electric current is adjusted parameter default C after decoding, for controlling the second input current I _tRIM.

As shown in above-mentioned formula 2, this preset lines sexual intercourse is:

T _OUT＝A.μ+B；

Wherein, T _oUTfor actual temperature output valve variable, μ is that temperature characterizes predetermined variable, and A is slope default value, and B is intercept default value.A=680, B=280, now inserting in principle A and B-register value can be arbitrary value, but facilitates general sense circuit simulation value for calibrating.

As can be seen from above, T _oUTby A, B determines with the preset lines sexual intercourse of μ.As mentioned above, slope default value and intercept default value can be deposited with respectively in slope register 140 and intercept register 150.

In step S200, choose a point for measuring temperature T _w1, according to this linear relationship, obtain this temperature readout T1 under this point for measuring temperature.

Point for measuring temperature T _w1can be the arbitrary temp value in the effective output temperature of CMOS temperature sensor, example is T as shown in Figure 3 _w1=25 ℃.And, according to the slope default value A in preset lines sexual intercourse in formula 1 and intercept default value B, calculate the temperature readout T1 under this point for measuring temperature.

At step S300, according to this point for measuring temperature and this temperature readout, this electric current is adjusted to parameter default and adjust, until this point for measuring temperature and this temperature readout equate.

When adjusting, if T1 > is T _w1, by electric current, adjust register C and strengthen I _tRIM, until T1=T _w1complete temperature sensor calibration, the value that electric current is adjusted in register C is calibration value; If T1 < is T _w1, by electric current, adjust register C and reduce I _tRIM, until T1=T _w1complete temperature sensor calibration, the value that electric current is adjusted in register C is calibration value.Thus, complete the calibration to temperature sensor.

In sum, the temperature correction device of integrated CMOS temperature sensor of the present utility model does not need impressed voltage source, as long as temperature test point just can be calibrated to temperature sensor in-55 ℃～125 ℃ temperature ranges ± precision of 0.2 ℃, calibration speed is fast, do not increase peripheral circuit, therefore greatly reduce testing cost.

Claims (3)

1. a temperature correction device for integrated CMOS temperature sensor, comprises CMOS temperature sensor, and this CMOS temperature sensor comprises:

The first temperature sign amount output circuit, for according to the multiple of the first input current and this first input current, exports the first temperature sign amount;

The second temperature sign amount output circuit, be used for according to the second input current, export the second temperature sign amount, this first temperature sign amount and this second temperature sign amount determine a temperature coefficient, and temperature readout and this temperature coefficient of this CMOS temperature sensor are linear;

It is characterized in that, this temperature correction device also comprises:

Slope register, for depositing the slope default value of this linear relationship;

Intercept register, for depositing the intercept default value of this linear relationship;

Data processing unit, it is connected with this integrated CMOS temperature sensor, this slope register and this intercept register, for according to this linear relationship, determines described temperature readout;

Temperature value registers, it is connected with this data processing unit, for depositing described temperature readout;

Electric current is adjusted register, for depositing electric current, adjusts parameter;

Demoder, it is connected with this CMOS temperature sensor with this electric current adjustment register, decodes, and utilize decoded electric current to adjust parameter this second input current is adjusted for this electric current is adjusted to parameter.

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

3. integrated CMOS temperature sensor according to claim 1 and 2, is characterized in that,

Described the first temperature sign amount output circuit comprises in parallel the first triode and the second triode, and this first triode is connected with the first mirror current source, and this second triode is connected with the second mirror current source;

Described the second temperature sign amount output circuit comprises the 3rd triode, and the 3rd triode is connected with the 3rd mirror current source.

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