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CN1645742A - Digital temperature compensating method and circuit for analog computing amplifier - Google Patents

Digital temperature compensating method and circuit for analog computing amplifier Download PDF

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Publication number
CN1645742A
CN1645742A CN 200510053748 CN200510053748A CN1645742A CN 1645742 A CN1645742 A CN 1645742A CN 200510053748 CN200510053748 CN 200510053748 CN 200510053748 A CN200510053748 A CN 200510053748A CN 1645742 A CN1645742 A CN 1645742A
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CN
China
Prior art keywords
analog computing
computing amplifier
output valve
chip microcomputer
analog
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Pending
Application number
CN 200510053748
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Chinese (zh)
Inventor
李仁贵
庄东霖
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XINCHEN SCIENCE AND TECHNOLOGY Co Ltd
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XINCHEN SCIENCE AND TECHNOLOGY Co Ltd
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Priority to CN 200510053748 priority Critical patent/CN1645742A/en
Publication of CN1645742A publication Critical patent/CN1645742A/en
Pending legal-status Critical Current

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Abstract

The invention consists of an electronic switch, an analog operational amplifier, a feedback circuit and a single-chip microcomputer (SCM). The inverted input end and non-inverted input end of the analog operational amplifier can be provided to external input source for connection. The output end makes parallel connection with the A/D input end of SCM, and is connected with inverted input end through the feedback circuit. The electronic switch is connected with the inverted input end and non-inverted input end of the analog operational amplifier, and the SCM uses the switching of electronic switch to get the output value of analog operational amplifier generated from temperature effect under no external input source caused by short circuit of input end and the output value obtained after adding external input source. After the output value of non external input source is subtracted through SCM operation, the analog operational amplifier is made to reach the effect of temperature compensation.

Description

A kind of analog computing amplifier digital temperature compensating method and circuit thereof
Technical field
The invention relates to a kind of analog computing amplifier digital temperature compensating method, refer to use a kind of analog computing amplifier digital temperature compensating circuit of single-chip microcomputer and electronic switch especially.
Background technology
Analog computing amplifier (OPA) is a kind of amplifier that uses feedback circuit to carry out high enlargement ratio computing, is applied to carry out in the Analogical Electronics enlarging function usually.But this analog computing amplifier (OPA) has along with working temperature produces offset voltage (Offset Voltage, Vos) characteristic, and when in a single day analog computing amplifier (OPA) produces offset voltage Vos, the output valve of analog computing amplifier (OPA) will produce corresponding drift and error along with offset voltage Vos, and this phenomenon is loosely referred to as the temperature effect of analog computing amplifier (OPA).
When especially being applied to analog computing amplifier (OPA) in one group of detection system, the output valve of detection system will inevitably be subjected to the temperature effect phenomenon influence of analog computing amplifier (OPA) and cause error, so can cause the precision of detection system to reduce.
Therefore, be subjected to the output valve error that the temperature effect influence is produced in order to reduce and to proofread and correct analog computing amplifier (OPA), a kind of technique for temperature compensation of analog computing amplifier (OPA) that is applied to is promptly in response to developing out.The practice of this technique for temperature compensation all utilizes an ambient temperature measurement assembly to come measure analog operational amplifier (OPA) ambient temperature on every side usually, with in measured temperature-compensating and the analog computing amplifier that is added to (OPA), under the different operating temperature, produce the output drift again to reduce analog computing amplifier (OPA).
With a kind of pressure gauge circuit 10 that is applied to pressure gauge and is provided with temperature-compensation circuit shown in Figure 1 is example, and this pressure gauge circuit 10 is made of jointly an operation amplifier circuit 11, certain voltage circuit 12, a pressure measurement circuitry 13 and a temperature-compensation circuit 14.Wherein, manometric pressure measurement circuitry 13 is to be used for gaging pressure, and the pressure that measures is input to operation amplifier circuit 11 with magnitude of voltage carries out high enlargement ratio computing, but for avoiding operation amplifier circuit 11 to cause offset voltage Vos to cause corresponding error to produce because of being subjected to temperature effect influence, 10 in this pressure gauge circuit carries out temperature-compensating by fixed voltage circuit 12 and 14 pairs of operation amplifier circuits of temperature-compensation circuit 11.
Its principle is after utilizing the ambient temperature of thermistor RT2 measuring operational amplifier circuit 11 of the thermistor RT1 of fixed voltage circuit 12 and temperature-compensation circuit 14, convert measured ambient temperature to magnitude of voltage again, and among compensation and be added to analog computing amplifier A and the analog computing amplifier C.Therefore, when in a single day temperature changes, thermistor RT1 and RT2 will measure different ambient temperatures, and through converting corresponding different partial pressure value to and being added to behind the operation amplifier circuit 11, operation amplifier circuit 11 just can be exported and obtain the output valve that proper temperature compensates.
But, be applied to the said temperature compensation technique of analog computing amplifier (OPA) at present, but still staying in employing compensates with analog form, after long-time the use, the precision of analog computing amplifier (OPA) can still need be proofreaied and correct just and can guarantee precision gradually because of often distortion of the permanent accumulation of error.
But the signal processing and the demonstration of general measure assembly have developed into the digitized stage in recent years at present, especially widely use single-chip microcomputer in the general circuit and handle digitized signal and demonstration.Therefore, be necessary by easy circuit design in fact, the technique for temperature compensation that is applied to analog computing amplifier (OPA) is at present proposed to improve, utilize single-chip microcomputer with the digital control temperature-compensating of carrying out analog computing amplifier to rise to.
Summary of the invention
So, main purpose of the present invention is to disclose a kind of digital temperature compensating method that is applied to analog computing amplifier, especially the working temperature at analog computing amplifier is under the environment of meeting acute variation, and more being applicable to the analog computing amplifier compensation and proofreading and correct because of being subjected to temperature effect influences the output valve error that is produced.For solving the problems of the technologies described above, the invention provides provides a kind of digital temperature compensating method that is applied to analog computing amplifier, it is characterized in that: at first make the inverting input of analog computing amplifier and non-inverting input form short circuit, to obtain the digitlization offset voltage output valve A that analog computing amplifier is really produced because of the temperature effect influence, again output valve A is compensated to analog computing amplifier and then under the situation of outside input source is arranged among the obtained digitlization output valve B, make analog computing amplifier obtain the output valve that temperature-compensating and output are not influenced by offset voltage.
Another main purpose of the present invention is to disclose a kind of analog computing amplifier digital temperature compensating circuit, comprise an electronic switch, an analog computing amplifier, a feedback circuit and a single-chip microcomputer, it is characterized in that: the inverting input of analog computing amplifier and non-inverting input can offer outside input source and connect, and output is parallel-connected to the A/D input of described single-chip microcomputer and is connected to inverting input via described feedback circuit; The inverting input and the non-inverting input of the described analog computing amplifier of described electronic switch cross-over connection, and open and close switching by described Single-chip Controlling, and the switching of switching described electronic switch of described single-chip microcomputer by control, resulting output valve after can obtaining analog computing amplifier and not having the output valve of outside input source and add input source.Described single-chip microcomputer can be carried out following workflow, comprising:
A. set analog-to-digital (A/D) function;
B. driving the described electronic switch of Single-chip Controlling is in and is channel status;
C. single-chip microcomputer is obtained the output valve AD1 that analog computing amplifier does not have the input signal source;
D. driving the described electronic switch of Single-chip Controlling is in and is off state;
E. single-chip microcomputer is obtained the output valve AD2 that contains output valve AD1; And
F. carry out the temperature-compensating correction, calculate by output valve AD2 deduction output valve AD1.
The software of described single-chip microcomputer can be carried out and set up single-chip microcomputer on their own and read the time of offset and the step of layout.
Analog computing amplifier is through after the digital temperature compensating method shown in the present, its output voltage has only very small variation with the variation of ambient temperature, obtained good temperature-compensating, so digital temperature compensating method shown in the present can effectively solve analog computing amplifier because of the thermal drift phenomenon that temperature effect produced, and has improved the precision of detection system.
Description of drawings
Fig. 1 is a kind of pressure gauge circuit that is applied to pressure gauge and is provided with temperature-compensation circuit;
Fig. 2 is a kind of digital temperature compensating circuit block diagram that is applied to analog computing amplifier shown in the present;
Fig. 3 is a scm software flow chart used in the present invention;
Fig. 4 is the experimental data figure that digital temperature compensating method shown in the present is applied to analog computing amplifier.
[primary clustering symbol description]
10. pressure gauge circuit 11. operation amplifier circuits
12. fixed voltage circuit 13. pressure measurement circuitry
14. temperature-compensation circuit
20. analog computing amplifier digital temperature compensating circuit
21. single-chip microcomputer 22. electronic switches
23. analog computing amplifier 24. feedback circuits
25. offset voltage 30. is measured assembly
Embodiment
As shown in Figure 2, analog computing amplifier digital temperature compensating circuit 20 shown in the present is made of jointly a single-chip microcomputer 21, an electronic switch 22, an analog computing amplifier 23 and a feedback circuit 24.
Wherein, the inverting input of analog computing amplifier 23 and non-inverting input provide to measuring assembly 30 and constitute electric connection, make the input signal of measuring assembly 30 to add from the inverting input and the non-inverting input of analog computing amplifier 23.
And the output of analog computing amplifier 23 is parallel to the analog-to-digital input port (A/D input port) of single-chip microcomputer 21 and the input of feedback circuit 24, and the output of feedback circuit 24 is connected to the inverting input of analog computing amplifier 23.So, the output signal of analog computing amplifier 23, after on the one hand changing into digital signal via the A/D input port of single-chip microcomputer 21, import internal memory (MEMORY) storage of single-chip microcomputer 21 again, by feedback circuit 24 output signal is fed back the inverting input of input analog computing amplifier 23 on the other hand again again.
Electronic switch 22 is a kind ofly to be in the normal open switch that is off state usually, and cross-over connection is in the inverting input and the non-inverting input of analog computing amplifier 23, but the switching of electronic switch 22 switches, and is directly to be controlled by the output of single-chip microcomputer 21.
Therefore, be in when being channel status by single-chip microcomputer 21 control electronic switches 22, the inverting input of analog computing amplifier 23 and non-inverting input will form short circuit, and analog computing amplifier 23 forms obtained output valve under the situation of short circuit at inverting input and non-inverting input, is exactly analog computing amplifier 23 obtained output valve under the situation of no outside input source.Therefore, obtained in this case output valve, be exactly that analog computing amplifier 23 very influences the output valve of the offset voltage 25 that is just being produced because of being subjected to temperature effect, and via the A/D input port of single-chip microcomputer 21 with the output valve of offset voltage 25 by analog signal revolution word signal after, can be stored in the internal memory of single-chip microcomputer 21.
In like manner, be in when being off state by single-chip microcomputer 21 control electronic switches 22, do not cause short circuit between the inverting input of analog computing amplifier 23 and the non-inverting input, just can add from the inverting input and the non-inverting input of analog computing amplifier 23 so measure the input signal of assembly 30.Therefore, the output valve that analog computing amplifier 23 is obtained in this case, comprise exactly and measure assembly 30 pairing output valves and add because of being subjected to temperature effect and influence the sum total of offset voltage 25 output valves that produced, and via the A/D input port of single-chip microcomputer 21 with analog signal revolution word signal after, also can be stored in the internal memory of single-chip microcomputer 21.
So, can calculate by the ALU (ALU) of single-chip microcomputer 21, after the output valve of analog computing amplifier 23 sum total deduction cut offset voltage 25 output valves that analog computing amplifier 23 influences by temperature effect to be produced, resulting result is exactly analog computing amplifier 23 is not influenced by offset voltage 25 through temperature-compensating a output valve, is exactly the only corresponding output variable of measuring assembly 30 input values of analog computing amplifier 23.
Therefore, a kind of digital temperature compensating method that is applied to analog computing amplifier shown in the present is to comprise:
1. obtain the digitlization output valve A of analog computing amplifier 23 under the situation of inverting input and non-inverting input formation short circuit earlier, that is, obtain the digitlization offset voltage 25 output valve A that analog computing amplifier 23 is produced because of the temperature effect influence under the situation of no outside input source;
2. output valve A is compensated to analog computing amplifier 23 and then under the situation of outside input source is arranged among the obtained digitlization output valve B, promptly, after output valve B deduction cuts output valve A, make analog computing amplifier 23 obtain the output valve that temperature-compensating and output are not influenced by offset voltage 25.
And, analog computing amplifier digital temperature compensating circuit 20 shown in the present is to utilize the software of 21 burnings of single-chip microcomputer to implement digital temperature compensating method shown in the present, so the software of single-chip microcomputer 21 can order about the control unit (CU) of single-chip microcomputer 21 and carry out workflow shown in Figure 3, comprising:
A. set the function of analog-to-digital (A/D);
After power supply, single-chip microcomputer 21 softwares can activate the function and the setup parameter value of analog-to-digital (A/D), promptly carry out step b after finishing parameter setting.
B. driving single-chip microcomputer 21 control electronic switches 22 is in and is channel status;
C. single-chip microcomputer 21 is obtained the A/D value and is saved as AD1;
The A/D value that single-chip microcomputer 21 is obtained in the case is exactly the offset voltage 25 output valve AD1 that analog computing amplifier 23 is produced because of the temperature effect influence under the state in no input signal source; Treat single-chip microcomputer 21 carry out confirm whether to finish read AD1 value after, the control unit of single-chip microcomputer 21 (CU) execution is stored into AD1 in the internal memory.
D. driving single-chip microcomputer 21 control electronic switches 22 is in and is off state;
E. single-chip microcomputer 21 is obtained the A/D value and is saved as AD2;
The A/D value that single-chip microcomputer 21 is obtained in the case contains the output valve AD2 of offset voltage 25 output valve AD1 exactly; Treat single-chip microcomputer 21 carry out confirm whether to finish read AD2 value after, the control unit of single-chip microcomputer 21 (CU) execution is stored into AD2 in the internal memory.
F. begin to carry out the temperature-compensating correction;
ALU (ALU) by single-chip microcomputer 21 calculates by output valve AD2 deduction output valve AD1, and resulting final result is exactly the output valve that analog computing amplifier 23 passes through temperature-compensatings and not influenced by offset voltage 25.
In addition, operational environment demand according to analog computing amplifier 23, analog computing amplifier digital temperature compensating circuit 20 shown in the present can set up time and the layout that reads offset on their own by single-chip microcomputer 21, so the present invention is applicable to the different application and the demand of various analog computing amplifiers 23.
Fig. 4 is an experimental data figure of the present invention, when temperature rises, the offset voltage of analog computing amplifier 23 can rise with temperature, and the drift phenomenon that offset voltage caused can directly be reflected in the output of analog computing amplifier 23, make the output voltage of analog computing amplifier 23 also vary with temperature and change, so can cause error in the measurement.
Therefore, if can measure analog computing amplifier 23 side-play amounts that cause because of working temperature, just can overcome analog computing amplifier 23 because of drift error that temperature effect caused.
Show that by experimental data figure when temperature rises to 50 when spending by 29 degree Celsius, analog computing amplifier 23 can rise with the temperature increase, and analog computing amplifier 23 pairing outputs also can vary with temperature because of being subjected to the side-play amount of offset voltage influence.But analog computing amplifier 23 is through after the digital temperature compensating method shown in the present, temperature rises to 50 when spending by 29 degree, the output of analog computing amplifier 23 all maintains fixed value, so digital temperature compensating method shown in the present can effectively solve analog computing amplifier 23 really because of thermal drift phenomenon that temperature effect produced.

Claims (4)

1, a kind of digital temperature compensating method that is applied to analog computing amplifier, it is characterized in that: at first make the inverting input of analog computing amplifier and non-inverting input form short circuit, to obtain the digitlization offset voltage output valve A that analog computing amplifier is really produced because of the temperature effect influence, again output valve A is compensated to analog computing amplifier and then under the situation of outside input source is arranged among the obtained digitlization output valve B, make analog computing amplifier obtain the output valve that temperature-compensating and output are not influenced by offset voltage.
2, a kind of analog computing amplifier digital temperature compensating circuit, comprise an electronic switch, an analog computing amplifier, a feedback circuit and a single-chip microcomputer, it is characterized in that: the inverting input of analog computing amplifier and non-inverting input can offer outside input source and connect, and output is parallel-connected to the A/D input of described single-chip microcomputer and is connected to inverting input via described feedback circuit; The inverting input and the non-inverting input of the described analog computing amplifier of described electronic switch cross-over connection, and open and close switching by described Single-chip Controlling, and the switching of switching described electronic switch of described single-chip microcomputer by control, resulting output valve after can obtaining analog computing amplifier and not having the output valve of outside input source and add input source.
3, a kind of analog computing amplifier digital temperature compensating circuit as claimed in claim 2, it is characterized in that: described single-chip microcomputer can be carried out following workflow, comprising:
A. set analog-to-digital (A/D) function;
B. driving the described electronic switch of Single-chip Controlling is in and is channel status;
C. single-chip microcomputer is obtained the output valve AD1 that analog computing amplifier does not have the input signal source;
D. driving the described electronic switch of Single-chip Controlling is in and is off state;
E. single-chip microcomputer is obtained the output valve AD2 that contains output valve AD1; And
F. carry out the temperature-compensating correction, calculate by output valve AD2 deduction output valve AD1.
4. a kind of analog computing amplifier digital temperature compensating circuit as claimed in claim 3 is characterized in that: described single-chip microcomputer can be carried out and set up single-chip microcomputer on their own and read the time of offset and the step of layout.
CN 200510053748 2005-03-11 2005-03-11 Digital temperature compensating method and circuit for analog computing amplifier Pending CN1645742A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN 200510053748 CN1645742A (en) 2005-03-11 2005-03-11 Digital temperature compensating method and circuit for analog computing amplifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN 200510053748 CN1645742A (en) 2005-03-11 2005-03-11 Digital temperature compensating method and circuit for analog computing amplifier

Publications (1)

Publication Number Publication Date
CN1645742A true CN1645742A (en) 2005-07-27

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Application Number Title Priority Date Filing Date
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102483795A (en) * 2009-02-18 2012-05-30 模拟设备股份有限公司 Analog computing
CN102969991A (en) * 2012-11-22 2013-03-13 昆山北极光电子科技有限公司 Low-offset automatic compensation circuit
CN104515611A (en) * 2013-09-29 2015-04-15 中兴通讯股份有限公司 Temperature sensing circuit and temperature sensor
CN104539245A (en) * 2014-11-11 2015-04-22 深圳市华星光电技术有限公司 Self-zeroing circuit of operational amplifier

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102483795A (en) * 2009-02-18 2012-05-30 模拟设备股份有限公司 Analog computing
CN102483795B (en) * 2009-02-18 2015-09-09 模拟设备股份有限公司 Methods, circuits and integrated circuits for performing operations
CN102969991A (en) * 2012-11-22 2013-03-13 昆山北极光电子科技有限公司 Low-offset automatic compensation circuit
CN104515611A (en) * 2013-09-29 2015-04-15 中兴通讯股份有限公司 Temperature sensing circuit and temperature sensor
CN104539245A (en) * 2014-11-11 2015-04-22 深圳市华星光电技术有限公司 Self-zeroing circuit of operational amplifier
WO2016074261A1 (en) * 2014-11-11 2016-05-19 深圳市华星光电技术有限公司 Self zero setting circuit of operational amplifier

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