CN100445712C - Temp. measuring circuit of corrected by translation conversion reference level - Google Patents

Abstract

A temperature measuring circuit utilizing translation converting reference level to carry out calibration is prepared as exerting at least two currents on heat transducer by current exciting circuit to let heat transducer generate two output signals correspondingly, using calculation circuit to calculate out an analog temperature signal representing temperature detected by heat detector, converting analog signal to be digital temperature signal by A/D conversion circuit according to a conversion reference level, carrying out translation regulation of said reference level according to calibration value generated by calibration value generation circuit.

Description

By the temperature measuring circuit of translation conversion reference level to proofread and correct

Technical field

The present invention system relates to a kind of temperature measuring circuit, relates in particular to the temperature measuring circuit that a kind of conversion reference level by translation analog to digital change-over circuit is realized error correcting function.

Background technology

Because the semiconductor pn of diode assembly meets the base stage of face or transistor component and the semiconductor pn between emitter-base bandgap grading and connects be relative to each other connection and be the function of temperature of potential difference (PD) that the face two ends are presented and therebetween the electric current of flowing through, and comes detected temperatures so extensively utilize this semiconductor pn to connect face in technical field of integrated circuits.Fig. 1 has shown the circuit composition synoptic diagram of existing temperature measuring circuit 10.Typically, temperature measuring circuit 10 is provided to monitor the temperature of ambient systems 20.For example, ambient systems 20 is a computing machine, electronic installation or specific circuit region, and wherein being provided with to provide semiconductor pn to connect the thermal sensor 21 of face with detected temperatures.As shown in the figure, thermal sensor 21 is implemented by a pnp two-carrier transistor, and the semiconductor pn between its base stage and emitter-base bandgap grading connects face in order to detected temperatures.

In temperature measuring circuit 10, the switch S of current source circuit 11 ₁With S ₂By control circuit 12 decision conductings and not conducting, so that allow different electric current I respectively ₁With I ₂Be applied to thermal sensor 21.Suppose electric current I ₁Being applied to base stage and the potential difference (PD) between emitter-base bandgap grading that thermal sensor 21 caused is V _BE1And electric current I ₂Being applied to base stage and the potential difference (PD) between emitter-base bandgap grading that thermal sensor 21 caused is V _BE2, then counting circuit 13 makes potential difference (PD) V _BE1With V _BE2Can obtain following equation (1) after subtracting each other each other:

$\mathrm{\&Delta;}{V}_{\mathrm{BE}}=V_{\mathrm{BE}1}-V_{\mathrm{<figure-callout\; id="2"\; label="BE"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">BE</figure-callout>}2}=\frac{\mathrm{KT}}{q}\ln \left(\frac{I_1}{I_2}\right)+(I_1-I_2)(R_e+\frac{R_b}{\mathrm{\&beta;}})---\left(1\right)$

Wherein K is that Bo Ziman (Boltzmann) constant, T are that absolute temperature, q are elementary charge, R _eSeries connection dead resistance, R for emitter-base bandgap grading _bFor the series connection dead resistance and the β of base stage is transistorized gain coefficient (gain).Therefore, the potential difference (PD) Δ V that produced of counting circuit 13 _BEBut be one to vary with temperature and the simulating signal of representation temperature.Subsequently, (analog-to-digital converter ADC) 14 makes this analog temperature conversion of signals become a digital temperature signal to the analog to digital change-over circuit.

From equation (1) as can be known, the series connection dead resistance R of thermal sensor 21 _eWith R _bCause a temperature independent constant term, that is (I ₁-I ₂) (R _e+ R _b/ β).In order to eliminate this kind series connection dead resistance R _eWith R _bThe error that is caused, prior art are used three kinds or more kinds of different electric current usually, excite identical thermal sensor 21 in regular turn, realize temperature measurement result accurately with expectation.Yet, use the existing mode of excitation of three kinds or more kinds of different electric current not only to cause operating frequency to increase rapidly but also more cause unnecessary energy consumption and temperature change.Even keep under the fixing condition at operating frequency, the mode of excitation in regular turn of more kinds of different electric currents will prolong each required time of temperature survey circulation inevitably, thereby reduce the reaction velocity of temperature measuring circuit 10.

On the other hand, what temperature measuring circuit 10 was in fact measured is the temperature that is formed with the semiconductor substrate of thermal sensor 21 on it, and this measurement result may be also inequality with the authentic representative of ambient systems 20 degree warm in nature.For example, when ambient systems 20 is a computing machine, the temperature of the heat sink of normally measuring ambient systems 20 22 that people are interested in, but not be provided with the temperature of the semiconductor substrate of thermal sensor 21.In this case, the manufacturer of ambient systems 20 provides the temperature contrast data Δ that exists between the substrate of relevant heat sink 22 and thermal sensor 21 T, so that existing temperature measuring circuit 10 is stored in it in buffer 15.Subsequently, adding circuit 16 is with the numeral output of analog to digital change-over circuit 14 and the temperature contrast data Δ T addition each other in the buffer 15, so that produce a final temperature signal Tmp.

Summary of the invention

Because foregoing problems the object of the present invention is to provide a kind of temperature measuring circuit, realize error correcting function by the conversion reference level of translation analog to digital change-over circuit.

According to an aspect of of the present present invention, a kind of temperature measuring circuit is provided, have an electric current energizing circuit, a counting circuit, a correction value generating circuit and an analog to digital change-over circuit.The electric current energizing circuit applies at least two electric current to thermal sensors in regular turn, makes this thermal sensor produce at least two output signals accordingly.In response to these at least two output signals, counting circuit calculates an analog temperature signal, and it represents the detected temperature of this thermal sensor.Correction value generating circuit produces a corrected value.The analog to digital change-over circuit becomes a digital temperature signal according to a conversion reference level with this analog temperature conversion of signals.The translation adjustment of this conversion reference level according to this corrected value.

This thermal sensor has semiconductor pn and connects face, makes these at least two electric currents to flow through in regular turn this semiconductor pn connects face and produce at least two potential difference (PD) thereon respectively, as these at least two output signals.This corrected value is to apply at least three electric currents to this thermal sensor in regular turn by this electric current energizing circuit to calculate, and makes this corrected value in order to revise a constant term error of this analog temperature signal.This thermal sensor system is arranged in the substrate of an ambient systems.This corrected value is provided by this ambient systems, with the difference between the representative temperature of revising detected this temperature of this thermal sensor and this ambient systems.

According to another aspect of the present invention, a kind of thermometry is provided, have the following step.At first, apply at least two electric current to thermal sensors in regular turn, make this thermal sensor produce at least two output signals accordingly.Calculate an analog temperature signal in response to these at least two output signals, it represents the detected temperature of this thermal sensor.Produce a corrected value.According to a conversion reference level this analog temperature conversion of signals is become a digital temperature signal.The translation adjustment of this conversion reference level according to this corrected value.

According to another aspect of the present invention, provide a kind of electric current energizing circuit, in order to excite a thermal sensor.This electric current energizing circuit has a measuring current source circuit, a correcting current source circuit, a correction control circuit and a circuit of measurement and control.The measuring current source circuit provides one first to measure electric current and one second measurement electric current.The correcting current source circuit provides a correcting current.Correction control circuit allows this first measurement electric current, this second measurement electric current, is applied to this thermal sensor in regular turn with this correcting current, in order to measure the constant term error relevant for this thermal sensor.Circuit of measurement and control allows this first measurement electric current and this second measurement electric current to be applied to this thermal sensor in regular turn, in order to measure a temperature of this thermal sensor.This correction control circuit is activated to carry out the measurement of this constant term error than this circuit of measurement and control is more Zao.

Description of drawings

Fig. 1 has shown the circuit composition synoptic diagram of existing temperature measuring circuit;

Fig. 2 has shown the circuit composition synoptic diagram according to temperature measuring circuit of the present invention;

Fig. 3 (A) has shown the mode of operation figure of foundation counting circuit of the present invention to 3 (C);

Fig. 4 has shown the principle of operation synoptic diagram according to translation correction type analog to digital change-over circuit of the present invention; And

Fig. 5 shows according to the detailed circuit diagram of example of analog to digital change-over circuit of the present invention.

The primary clustering symbol description

10, temperature measuring circuit 11, current source circuit

12, control circuit 13, counting circuit

14, analog to digital change-over circuit (ADC) 15, buffer

16, adding circuit 20, ambient systems

21, thermal sensor 22, heat sink

30, temperature measuring circuit 31, measuring current source circuit

32, correcting current source circuit 33, circuit of measurement and control

34, correction control circuit 35, counting circuit

36, correction value generating circuit

37, translation correction type analog to digital change-over circuit (ADC)

41, multiplier 42, totalizer

43, proofread and correct buffer 51, sampling/modulation circuit

52, clock pulse generator 53, counter

54, frequency eliminator 55, output state

AM, differential amplifier C _a～C _d, electric capacity

CF, corrected value CLK, clock signal

I ₁, I ₂, measure electric current I ₃, correcting current

R _b, R _e, series connection dead resistance RST, reset signal

S ₁, S ₂, S ₃, S _a～S _d, switch Tmp, temperature measurement result

V _BE, the potential difference (PD) d Δ V between base stage and emitter-base bandgap grading _BE, the constant term error

Δ T, temperature contrast data

Embodiment

Explanation hereinafter and accompanying drawing will make aforementioned and other purpose of the present invention, feature, more obvious with advantage.Now describe in detail according to preferred embodiment of the present invention with reference to the accompanying drawings.

Fig. 2 has shown the circuit composition synoptic diagram according to temperature measuring circuit 30 of the present invention.In temperature measuring circuit 30, a kind of electric current energizing circuit is made of jointly a measuring current source circuit 31, a correcting current source circuit 32, a circuit of measurement and control 33 and 34 of correction control circuits.Measuring current source circuit 31 has first and second and measures electric current I ₁With I ₂, respectively via switch S ₁With S ₂And be supplied to the emitter-base bandgap grading of thermal sensor 21.Correcting current source circuit 32 has a correcting current I ₃, via switch S ₃And be supplied to the emitter-base bandgap grading of thermal sensor 21.Before temperature measuring circuit 30 began to measure the temperature of thermal sensor 21, correction control circuit 34 must be activated earlier and measure electric current I to control first and second ₁With I ₂And correcting current I ₃Be applied to thermal sensor 21 in regular turn.Suppose electric current I ₁, I ₂, and I ₃Base stage that is caused for thermal sensor 21 and the potential difference (PD) between emitter-base bandgap grading are respectively V _BE1, V _BE2, and V _BE3, then counting circuit 35 can calculate shown in an equation (2) descends:

$\mathrm{\&Delta;}{V}_{\mathrm{<figure-callout\; id="1"\; label="BE"\; filenames="C20051011813600151.png,C20051011813600161.png"\; state="\{\{state\}\}">BE</figure-callout>}1}=V_{\mathrm{BE}1}-{\mathrm{<figure-callout\; id="2"\; label="V\; BE"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BE}}=\frac{\mathrm{KT}}{q}\ln \left(\frac{I_1}{I_2}\right)+(I_1-I_2)(R_e+\frac{R_b}{\mathrm{\&beta;}})$

$\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="2"\; label="V\; BE"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BE}}=V_{\mathrm{BE}2}-{\mathrm{<figure-callout\; id="3"\; label="V\; BE"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BE}}=\frac{\mathrm{KT}}{q}\ln \left(\frac{I_2}{I_3}\right)+(I_2-I_3)(R_e+\frac{R_b}{\mathrm{\&beta;}})$

$\mathrm{d\&Delta;}{V}_{\mathrm{BE}}={\mathrm{\&Delta;V}}_{\mathrm{BE}1}-{\mathrm{\&Delta;<figure-callout\; id="2"\; label="V\; BE"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{BE}}=\frac{\mathrm{KT}}{q}\ln \left(\frac{I_1*I_3}{{\mathrm{<figure-callout\; id="2"\; label="I"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">I</figure-callout>}}_2*I_2}\right)+(I_1-{2I}_2-I_3)(R_e+\frac{R_b}{\mathrm{\&beta;}})---\left(2\right)$

Suppose electric current I now again ₁, I ₂, and I ₃Between satisfy following ratio condition (3):

I ₁∶I ₂∶I ₃＝A ²∶A∶1 (3)

Promptly first measure electric current I ₁It is the second measurement electric current I ₂A doubly, and second measure electric current I ₂Be correcting current I ₃A doubly, wherein A is greater than zero, then equation (2) can further be simplified to equation as follows (4):

${\mathrm{d\&Delta;V}}_{\mathrm{BE}}={(A-1)}^2*{\mathrm{<figure-callout\; id="3"\; label="I"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">I</figure-callout>}}_3*(R_e+\frac{R_b}{\mathrm{\&beta;}})---\left(4\right)$

Therefore, by correcting current I ₃Help, counting circuit 35 can detect effectively by series connection dead resistance R _eWith R _bThe constant term error d Δ V that is caused _BESubsequently, this constant term error d Δ V _BEBe sent to correction value generating circuit 36 in order to produce corrected value CF.In a preferred embodiment, this corrected value CF must measure appropriately before any temperature survey circulation beginning in advance, used so that follow-up all temperature survey round-robin error corrections to be provided.

Fig. 3 (A) shows that to 3 (C) foundation counting circuit 35 of the present invention is detecting constant term error d Δ V _BEThe time mode of operation figure.In Fig. 3 (A), switch S _aConducting, switch S _bConducting, switch S _cMake capacitor C _cBe coupled to non-inverting input (+) and the switch S of differential amplifier A M _dMake capacitor C _dBe coupled to the inverting input (-) of differential amplifier A M.In addition, switch S ₁Conducting and switch S ₂With S ₃Not conductings, thereby only allow first to measure electric current I ₁Be applied to thermal sensor 21 and produce the first potential difference (PD) V between base stage and emitter-base bandgap grading _BE1In this phase one, because the voltage that the non-inverting input (+) of differential amplifier A M and inverting input (-) are located all is zero, so the output voltage V of differential amplifier A M _{Out (1)}Be zero.In Fig. 3 (B), switch S _aWith S _bAll become not conducting.In addition, switch S ₂Conducting and switch S ₁With S ₃Not conductings, thereby only allow second to measure electric current I ₂Be applied to thermal sensor 21 and produce the second potential difference (PD) V between base stage and emitter-base bandgap grading _BE2In this subordinate phase, because the voltage that the non-inverting input (+) of differential amplifier A M and inverting input (-) are located all is (V _BE1-V _BE2So)/2 are the output voltage V of differential amplifier A M _{Out (2)}Be (V _BE1-V _BE2).In Fig. 3 (C), switch S _cBecome and make capacitor C _cBe coupled to the inverting input (-) of differential amplifier A M, and switch S _dBecome and make capacitor C _dBe coupled to the non-inverting input (+) of differential amplifier A M.In addition, switch S ₃Conducting and switch S ₁With S ₂Not conductings, thereby only allow correcting current I ₃Be applied to thermal sensor 21 and produce the 3rd potential difference (PD) V between base stage and emitter-base bandgap grading _BE3In this phase III, the output voltage V of differential amplifier A M _{Out (3)}Become (V _BE1-V _BE2)-(V _BE2-V _BE3), i.e. the equation (2) of institute's desire detection and the constant term error d Δ V of (4) _BE

Please note according to correcting current source circuit among the present invention 32 and correction control circuit 34 and finish aforesaid constant term error d Δ V _BEThe detection measuring program and export correction value generating circuit 36 to after, i.e. shut-down operation.In other words, carrying out the temperature survey circulation time, temperature measuring circuit 30 only uses circuit of measurement and control 33 control survey current source circuits 31 to apply first and second in regular turn and measures electric current I ₁With I ₂To thermal sensor 21.Therefore, the mode of operation of counting circuit 35 in the temperature survey circulation only is confined to Fig. 3 (A) and 3 (B).Satisfy ratio condition (3) and recording the constant term error d Δ V of equation (4) _BESituation under, base stage that counting circuit 35 is obtained and the potential difference (PD) Δ V between emitter-base bandgap grading _BECan be expressed as follows:

$\mathrm{\&Delta;}{V}_{\mathrm{BE}}=V_{\mathrm{BE}1}-V_{\mathrm{<figure-callout\; id="2"\; label="BE"\; filenames="C20051011813600161.png"\; state="\{\{state\}\}">BE</figure-callout>}2}=\frac{\mathrm{KT}}{q}\ln \left(A\right)+\left(\frac{A}{A-1}\right)\mathrm{d\&Delta;}{V}_{\mathrm{BE}}---\left(5\right)$

Therefore, in the present invention, utilize first and second to measure electric current I ₁With I ₂The potential difference (PD) Δ V that is obtained _BEAs long as adjusted a constant term error d Δ V by translation _BEWith the product of scale factor A/ (A-1), can produce correct temperature measurement result.Because this constant term error d Δ V _BEIn advance via correcting current I ₃Assistance and detect and be stored in correction value generating circuit 36, so need not in each temperature survey circulation, to detect again repeatedly again.

Except constant term error d Δ V _BEOutside, the temperature contrast data Δ T of 22 of the relevant thermal sensor 21 that provided by ambient systems 20 and heat sinks also can be provided correction value generating circuit 36.Because constant term error d Δ V _BEBut all belong to the error that translation is proofreaied and correct with temperature contrast data Δ T, so correction value generating circuit 36 can be integrated into it single corrected value CF.Based on this corrected value CF, the suitable conversion reference level of translation correction type analog to digital change-over circuit 37 decisions.Fig. 4 shows the principle of operation synoptic diagram according to translation correction type analog to digital change-over circuit 37 of the present invention.Broadly, analog to digital change-over circuit 37 is taken a sample for the simulating signal Alg that is received according to a predetermined sampling frequency.Subsequently, take a sample and analog result on mathematical concept, can be considered via digital respective shaft Dx and convert a digital signal to, wherein the actual value of this digital signal depends on the relative position of conversion reference level REF.For example, as shown in Figure 4, original conversion reference level REF translation downwards behind the one corrected value CF and form conversion reference level REF_S after the translation.For original conversion reference level REF, analog sample AS converts digital signal Dgtl to.Have only for the conversion reference level REF_S after the translation, analog sample AS converts digital signal Dgt2 to.Therefore, by the mode of translation conversion reference level REF, translation correction type analog to digital change-over circuit 37 can carry out constant term error d Δ V effectively in the transfer process of analog to digital _BEObtain a correct temperature measurement result with the correction of temperature contrast data Δ T, need not additionally to practise existing additive operation program.

Fig. 5 shows the detailed circuit diagram according to the example of analog to digital change-over circuit 37 of the present invention.Sampling/modulation circuit 51 is according to clock signal CLK that clock pulse generator 52 provided and for from counting circuit 35 and base stage of coming and the potential difference (PD) Δ V between emitter-base bandgap grading _BETake a sample, and the sampling result modulation is become a pulse sequence signal.For example, sampling/modulation circuit 51 must be implemented by a Delta-Sigma analog to digital modulator, thereby this pulse sequence signal is the pairing digital signal of analog sample.The pulse sequence signal that comes from sampling/modulation circuit 51 is applied to counter 53.In a cycle of being scheduled to, the pulse number that counter 53 is counted in the received pulse sequence signal.Because the counting mode of counter 53 is upwards to increase progressively counting since a counting reference value, so translation adjusts that effect of this counting reference value is equal to promptly that translation adjusts that counter 53 calculates count results, so the inventor is applied to this know-why in the constant term error correction of temperature measurement result.

Particularly, the counting reference value of counter 53 is determined by the corrected value CF that correction value generating circuit 36 is provided.In correction value generating circuit 36, the constant term error d Δ V that comes from counting circuit 35 _BEBe multiplied by scale factor A/ (A-1) via multiplier 41, and subsequently via totalizer 42 with the temperature contrast data Δ T addition that comes from ambient systems 20, with synthetic desired single corrected value CF and be stored in and proofread and correct in the buffer 43.In other words, the embodiment shown in Figure 5 counting reference value of adjusting counter 53 by translation realizes the purpose of the translation conversion reference level REF of Fig. 4.On the other hand, frequency eliminator 54 is the clock signal CLK frequency elimination of clock pulse generator 52, resets signal RST with what produce a lower frequency.In one embodiment, the frequency of reseting signal RST that produced of frequency eliminator 54 gets the frequency of the clock signal CLK of clock pulse generator 52 divided by 1024.Therefore, through 1024 all after dates, counter 53 can be reset gets back to the counting reference value at clock signal CLK, so that restart counting.Similarly, this counting reference value is determined by the corrected value CF that correction value generating circuit 36 is provided.In addition, counter 53 in 1024 cycles of clock signal CLK, count and the result be sent to output state 55, export the external world to as temperature measurement result Tmp.This temperature measurement result Tmp also upgrades according to reseting the frequency of signal RST.

Though the present invention is illustrated as illustration by means of preferred embodiment, should understand: the invention is not restricted to this disclosed embodiments.On the contrary, this invention is intended to contain tangible for those of ordinary skills various modifications and similar configuration.Therefore, the scope of claim should be according to the widest annotation, and this type of is revised and similar configuration to contain all.

Claims (9)

1, a kind of temperature measuring circuit comprises:

One electric current energizing circuit is used for applying in regular turn at least two electric current to thermal sensors, makes this thermal sensor produce at least two output signals accordingly;

One counting circuit is used for calculating an analog temperature signal in response to these at least two output signals, and it represents the detected temperature of this thermal sensor;

One correction value generating circuit is used to produce a corrected value; And

One analog to digital change-over circuit becomes a digital temperature signal according to a conversion reference level with this analog temperature conversion of signals,

Wherein, this conversion reference level translation adjustment according to this corrected value.

2, temperature measuring circuit as claimed in claim 1, wherein:

This thermal sensor has semiconductor pn and connects face, makes these at least two electric currents to flow through in regular turn this semiconductor pn connects face and produce at least two potential difference (PD) thereon respectively, as these at least two output signals.

3, temperature measuring circuit as claimed in claim 1, wherein:

This corrected value applies at least three electric currents to this thermal sensor in regular turn by this electric current energizing circuit and calculates, and makes this corrected value be used to revise a constant term error of this analog temperature signal.

4, temperature measuring circuit as claimed in claim 3, wherein:

This constant term error is produced by at least one series connection dead resistance of this thermal sensor.

5, temperature measuring circuit as claimed in claim 1, wherein:

This thermal sensor is arranged in the substrate of an ambient systems, and

This corrected value is provided by this ambient systems, with the difference between the representative temperature of revising detected this temperature of this thermal sensor and this ambient systems.

6, temperature measuring circuit as claimed in claim 1, wherein:

This analog to digital change-over circuit comprises:

One sampling/modulation circuit produces a pulse sequence signal in response to this analog temperature signal, and

One counter produces a count results in response to this pulse sequence signal in a cycle of being scheduled to, it represents the number of the pulse of this pulse sequence signal,

Wherein, this count results increases progressively from a reference value, and this reference value is set by this corrected value.

7, a kind of thermometry comprises:

Apply at least two electric current to thermal sensors in regular turn, make this thermal sensor produce at least two output signals accordingly;

Calculate an analog temperature signal in response to these at least two output signals, it represents the detected temperature of this thermal sensor;

Produce a corrected value; And

According to a conversion reference level this analog temperature conversion of signals is become a digital temperature signal,

Wherein, this conversion reference level translation adjustment according to this corrected value.

8, a kind of electric current energizing circuit in order to excite a thermal sensor, comprises:

One measuring current source circuit is used to provide one first to measure electric current and one second measurement electric current;

One correcting current source circuit is used to provide a correcting current;

One correction control circuit is used to allow this first measurement electric current, this second measurement electric current and this correcting current to be applied to this thermal sensor in regular turn, so that measure the constant term error relevant for this thermal sensor; And

One circuit of measurement and control is used to allow this first measurement electric current and this second measurement electric current to be applied to this thermal sensor in regular turn, so that measure the temperature of this thermal sensor,

Wherein, this correction control circuit is activated carrying out the measurement of this constant term error than this circuit of measurement and control is more Zao, and

After this circuit of measurement and control was activated with the measurement of carrying out this temperature, this correction control circuit was shut-down operation.

9, electric current energizing circuit as claimed in claim 8, wherein:

This first measurement electric current is A a times of this second measurement electric current, and

This second measurement electric current is A a times of this correcting current, and wherein, A is greater than zero.

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