CN1289040A - Temperature sensing module - Google Patents
Temperature sensing module Download PDFInfo
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- CN1289040A CN1289040A CN 99120201 CN99120201A CN1289040A CN 1289040 A CN1289040 A CN 1289040A CN 99120201 CN99120201 CN 99120201 CN 99120201 A CN99120201 A CN 99120201A CN 1289040 A CN1289040 A CN 1289040A
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Abstract
The temp.-sensing module with temp. compensation circuit consisting of passive element contains an object temp. sensing element; an environmental temp. sensing element; a preamplifie consisting of active element for receiving first input signal of object temp. sensing element, amplifying and outputting object temp. signal; a temp. compensation circuit consisting of passive element for receiving second input signal of environmental temp. sensing element for outputting environmental temp. signal; an adder for receiving object temp. signal and environmental temp. signal, adding them to produce output electric signal so as to use the environmental temp. signal to compensate the temp. error of object temp. signal which is produced by different environmental temp..
Description
The present invention relates to the temperature sensing module, particularly constitute the temperature sensing module of temperature-compensation circuit with passive element.
Present many household electronic products dispose the temperature-sensitive module, and with the temperature of non-contact measurement mode measurement target object, for example ear thermometer, baking box and micro-wave oven etc.These temperature-sensitive modules mostly have the infra-red intensity that infrared detector (Infrared Detector) detects target object, to measure the temperature of target object.For example, ear thermometer is the infra-red intensity with thermoelectric pile (Thermopile) sensing ear-drum, and converts the body temperature demonstration to.Because during with the temperature of thermoelectric pile sensed object object, the output signal value of thermoelectric pile can be subjected to the influence of ambient temperature (ambient temperature), for example when environment temperature raise, the signal of thermoelectric pile can descend.Therefore if only detect the infra-red intensity of target object, then can produce the error in the measurement because of the difference of the ambient temperature of target object with single thermoelectric pile.
The U.S. the 5th, 826, No. 982 " temperature sensing module (Temperature Sensing Module) " patent then discloses a kind of temperature sensing module with ambient temperature compensate function.Fig. 1 promptly shows the basic structure of this kind temperature sensing module.As shown in the drawing, this temperature sensing module 100 comprises a temperature sensor 110, one first prime amplifier 120, one second prime amplifier 130 and a differential amplifier 140, and its output is connected in control module 200.Temperature sensor 110 comprise a thermoelectric pile 111 and with these thermoelectric pile 111 tight close thermistors 112.This thermoelectric pile 111 is to be used for the ultrared intensity that the sensed object object sent, and the electric signal that is produced passed to first prime amplifier 120, thermistor 112 then is used for the sensing ambient temperature, and the electric signal that is produced is passed to second prime amplifier 130.The voltage output signal that act as amplification thermoelectric pile 111 of first prime amplifier 120, second prime amplifier 130 then is used for amplifying the voltage output signal of thermistor 112.Differential amplifier 140 are output voltages of amplifying first prime amplifier 120 with the output voltage of second prime amplifier 130 between difference, and export the control circuit 200 of a voltage signal to the back grade.Owing to thermistor 112 can change its resistance value along with the variation of ambient temperature, therefore the change of the resistance value change that produces relative voltage signal compensates the sensing error of thermoelectric pile 111 thus, and solution is because of the error that variation caused of ambient temperature.
But, aforementioned temperature sensing module is amplified with the voltage output signal of 130 pairs of thermistors 112 of amplifier, and operational amplifier (Operation Amplifier) input two ends when running can form an offset voltage (Offset voltage), because the voltage output signal variation range of thermistor 112 is little, this offset voltage also can be sneaked into the voltage output signal of thermistor 112 and be amplified together, and causes than mistake; If will turn the operational amplifier that offset voltage just must additionally increase part or adopt high price down, can increase cost.
In view of the above problems, thus the objective of the invention is to propose a kind ofly constitutes the temperature sensing module that temperature-compensation circuit reduces error with passive element.
For realizing described purpose, temperature sensing module of the present invention is first input signal of receiving target temperature sensor and second input signal of environment temperature sensing element, and convert the output electric signal of representation temperature to, this module comprises a prime amplifier, it is made of active component, and receive described first input signal of described target temperature sensing element, be output as the target temperature signal and amplify; One temperature-compensation circuit is made of passive element, and receives described second input signal of described environment temperature sensing element, and is output as ambient temperature signal; And a totalizer receives described target temperature signal and described ambient temperature signal, and with this target temperature signal and this ambient temperature signal addition and be output as described output electric signal.
Fig. 1 is the basic comprising of known temperature sensing module;
Fig. 2 is the signal connection layout of temperature sensing module of the present invention;
Fig. 3 is the calcspar of temperature sensing module of the present invention;
Fig. 4 is the circuit diagram of temperature sensing module of the present invention.
Referring now to accompanying drawing temperature sensing module of the present invention is elaborated.
Figure 2 shows that the signal connection layout of temperature sensing module of the present invention.As shown in the drawing, temperature sensing module of the present invention comprises temperature-sensitive module 10, receive the signal Processing module 20 of output signal of temperature-sensitive module 10 and the control die set 30 that received signal is handled the output signal of module 20.These temperature-sensitive module 10 output two kinds of temperature signals, i.e. target temperature signal and ambient temperature signals.Signal Processing module 20 is promptly handled at target temperature signal and ambient temperature signal, produces the temperature output signal through temperature compensation.Control die set 30 can be according to the big or small displays temperature of this temperature output signal, or carries out other control action.
Fig. 3 is the calcspar of signal Processing module 20 of the present invention.As shown in the drawing, signal Processing module 20 comprise a receiving target temperature signal I1 prime amplifier 21, a reception environment temperature signal I2 temperature-compensation circuit 22 and with the totalizer 23 of the output signal addition of the output signal of prime amplifier 21 and temperature-compensation circuit 22.The operation result 01 of this totalizer 23 exports control die set 30 to, uses and utilizes control die set 30 to carry out follow-up control action.
Fig. 4 is the circuit diagram of signal Processing module 20 of the present invention.As shown in the drawing, temperature-sensitive module 10 comprises two kinds of temperature-sensing elements, and promptly the target temperature-sensing element 111, and thermoelectric pile for example is with environment temperature-sensing element 112, for example thermistor.Target temperature-sensing element 111 is infra-red intensities of inspected object, and produces target temperature signal I1, and environment temperature-sensing element 112 then is used for sensing ambient temperature (for example room temperature), and produces ambient temperature signal I2.
As shown in Figure 4, the prime amplifier 21 of signal Processing module 20 comprises one first operational amplifier 214, and three resistance 211,212 and 213.The anode of first operational amplifier 214 is connected an end of target temperature-sensing element 111, and negative terminal is connected an end of resistance 211 and 212 simultaneously, and the other end of resistance 211 then is connected the other end of target temperature-sensing element 111 and the anode of reference voltage 233.The output terminal of first operational amplifier 214 then is connected the other end of resistance 212 and an end of resistance 213.Therefore, utilize the resistance value that changes resistance 211 and 212 can adjust the enlargement ratio of this prime amplifier 21.
Temperature-compensation circuit 22 comprises the resistance 221 and 222 of two series connection.Resistance 221 is in parallel with environment temperature-sensing element 112, and an end is connected in the other end of resistance 213, and the other end is connected in series with resistance 222.The other end of resistance 222 then is connected to earthing potential.Totalizer 23 comprises one second operational amplifier 232 and a resistance 231.The negative terminal of this second operational amplifier 232 is connected in an end of resistance 231 and the link of resistance 213 and resistance 221, and its anode then is connected the anode of a reference potential 233, and its output terminal then is connected in the other end of resistance 231.The negative terminal of this reference potential 233 then is connected in earthing potential.
The first order of control die set 30 is a reverser, be (to be connected the positive input terminal of operational amplifier 214 when the anode of thermoelectric pile 111 because the output signal and the temperature variation of signal Processing module 20 are inversely proportional to, and when thermistor 112 is positive temperature coefficient (PTC), if the negative terminal of thermoelectric pile 111 is connected the positive input terminal of operational amplifier 214, and when thermistor 112 was negative temperature coefficient, then the output signal of signal Processing module 20 was directly proportional with temperature variation).This reverser comprises one the 3rd operational amplifier 301 and three resistance 302,303 and 304.The anode of the 3rd operational amplifier 301 is connected the anode of reference potential 233, and its negative terminal then is connected an end of three resistance 302,303 and 304 simultaneously.The other end of resistance 302 is connected the output terminal of second operational amplifier 232, and the other end of resistance 303 is connected earthing potential, and resistance 304 is connected the output terminal of the 3rd operational amplifier 301.This output signal can be used for the control circuit of back level.Certainly, the output of signal Processing module 20 also can be directly connected in back level control circuit.
The action of this signal Processing module 20 then is described.The thermoelectric pile 111 of temperature-sensitive module 10 promptly produces the voltage corresponding to this infra-red intensity after the infrared ray that receives the target object (not shown).This voltage is output as target temperature voltage V1, and produces target temperature electric current I 10 after amplifying through prime amplifier 21, and wherein the enlargement ratio of this prime amplifier 21 can be changed by the different resistance values of resistance 211 and 212.In addition, the temperature of the thermistor 112 sensing surrounding environment of temperature-sensitive module 10 forms the resistance value with respect to this environment temperature, because this thermistor 112 is in parallel with the resistance 221 of temperature-compensation circuit 22, and is series at resistance 222.Therefore, resistance 221 and 222 contact voltage V2 can change along with the change of thermistor 112, and become bucking voltage V2, and produce offset current I02.And the ratio of bucking voltage V2 can be changed by the different resistance values of resistance 221 and 222.V1 is proportional to target temperature electric current I 10 because of target temperature voltage, and bucking voltage V2 is proportional to offset current 102.Then, totalizer 23 will be connected the target temperature electric current I 10 and offset current I02 addition of anode, form I03, and export the voltage signal V3 with temperature compensation through resistance 231 backs.The variation range that this totalizer 23 can be come control output voltage V3 by the resistance value of adjusting resistance 231.
Table one temperature and signal change the table of comparisons
| State | ????Vt | ?I10 | ?I02 | ?I03 | ??V3 |
| One, AT: constant, TT: raise | ????↑ | ??↑ | ??- | ??↑ | ??↓ |
| Two, AT: constant, TT: reduce | ????↓ | ??↓ | ??- | ??↓ | ??↑ |
| Three, AT: raise TT: constant | ????↓ | ??- | ??↓ | ??- | ??- |
| Four, AT: reduce TT: constant | ????↑ | ??↑ | ??↑ | ??- | ??- |
AT: ambient temperature, TT: target object temperature
Reference table one, the variation of the each point signal (with reference to figure 4) that signal Processing module 20 of the present invention is described during corresponding to ambient temperature and target object temperature change, wherein the anode of thermoelectric pile 111 is connected in the positive input terminal of operational amplifier 214, and thermistor 112 is a positive temperature coefficient (PTC).This table one is listed the state of four kinds of temperature variation, is respectively state one to state four.State one is that the constant but target object temperature of ambient temperature raises; State two is that the constant but target object temperature of ambient temperature reduces; State three raises for ambient temperature but target object is temperature-resistant; State four reduces for ambient temperature but target object is temperature-resistant.Below promptly at the variation of the each point signal of these four kinds of state description signal Processing modules 20.
At first, state one is that the constant but target object temperature of ambient temperature raises.At this moment, the output valve Vt of thermoelectric pile 111 raises, so after the processing of this voltage Vt process operational amplifier, output voltage V 1 (I10) also raises relatively.Because ambient temperature is constant, so the resistance value of thermistor 112 is constant, so V2 (I02) is fixing.In this case, I03 recruitment=I10 recruitment, and output voltage V 3 is reduced.
State two is that the constant but target object temperature of ambient temperature reduces.At this moment, the output valve Vt of thermoelectric pile 111 reduces, so after the processing of this voltage Vt process operational amplifier, output voltage V 1 (I10) also reduces relatively.Because ambient temperature is constant, so the resistance value of thermistor 112 is constant, so V2 (I02) is fixing.So I03 reduction=I10 reduction, and output voltage V 3 is raise.
State three raises for ambient temperature but target object is temperature-resistant.At this moment, the output valve Vt of thermoelectric pile 111 reduces because of ambient temperature raises, and after this voltage Vt handled through operational amplifier, output voltage V 1 (I10) also reduced.In addition, because of ambient temperature raises, also become big relatively, the reduction that I02 is relative to the resistance value of the thermistor 112 of temperature coefficient.Therefore, as long as I01 is identical with the changing value of I02, I03 can be maintained fixed (I03=I02+I10), makes output valve V3 not influenced by ambient temperature.
State four reduces for ambient temperature but target object is temperature-resistant.At this moment, the output valve Vt of thermoelectric pile 111 raises because of ambient temperature reduces, and after this voltage Vt handled through operational amplifier, output voltage V 1 (I10) also raise.In addition, because of ambient temperature reduces, the resistance value of the thermistor 112 of positive temperature coefficient (PTC) also diminishes relatively, and the change that I02 is relative is big.Therefore, as long as I01 is identical with the changing value of I02, I03 can be maintained fixed (I03=I02+I01), makes output valve V3 not influenced by ambient temperature.
Temperature sensing module of the present invention is because of utilizing the control circuit of passive element as temperature compensation, directly produce a temperature-compensated voltage, and do not need to come amplifying signal by the computing of operational amplifier, can avoid among the bias voltage adding temperature-compensated voltage with this operational amplifier, and influence offset.
Though more than with embodiment temperature sensing module of the present invention is described, it only is a kind of illustration, does not therefore limit scope of the present invention, only otherwise break away from main idea of the present invention, those skilled in the art can carry out various distortion or change.For example, in an embodiment, thermistor 112 is in parallel with resistance 221, but also can be in parallel with resistance 222, also can form temperature-compensation circuit by other passive elements.
Claims (5)
1. a temperature sensing module comprises the target temperature sensing element of sensed object object infra-red intensity and the environment temperature sensing element of sensing ambient temperature, it is characterized by this module and comprises:
One prime amplifier is made of active component, and receives the target temperature input signal of described target temperature sensing element, is output as the target temperature signal and amplify;
One temperature-compensation circuit is made of passive element, and receives the environment temperature input signal of described environment temperature sensing element, and is output as ambient temperature signal; And,
One totalizer receives described target temperature signal and described ambient temperature signal, and with this target temperature signal and this ambient temperature signal addition and produce the output temperature signal;
Thereby compensate the temperature error that described target temperature signal is produced because of the ambient temperature difference by described ambient temperature signal.
2. temperature sensing module according to claim 1, wherein said target temperature sensing element is a thermoelectric pile.
3. temperature sensing module according to claim 1, wherein said environment temperature sensing element is a thermistor.
4. temperature sensing module according to claim 1, wherein said totalizer also comprises a reference voltage source.
5. temperature sensing module according to claim 1, wherein said temperature-compensation circuit comprises two resistance in seriess, one end of this resistance in series is connected the input end of described totalizer, and the other end connects with reference to ground connection, and described environment temperature sensing element is parallel to a wherein described resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99120201 CN1289040A (en) | 1999-09-17 | 1999-09-17 | Temperature sensing module |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 99120201 CN1289040A (en) | 1999-09-17 | 1999-09-17 | Temperature sensing module |
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| Publication Number | Publication Date |
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| CN1289040A true CN1289040A (en) | 2001-03-28 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 99120201 Pending CN1289040A (en) | 1999-09-17 | 1999-09-17 | Temperature sensing module |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103398784A (en) * | 2013-07-26 | 2013-11-20 | 江苏物联网研究发展中心 | Self-rectification circuit for infrared thermopile temperature sensor |
| WO2022142237A1 (en) * | 2020-12-29 | 2022-07-07 | 华润微集成电路(无锡)有限公司 | Predictive-type electronic body temperature thermometer circuit structure implementing temperature compensation |
-
1999
- 1999-09-17 CN CN 99120201 patent/CN1289040A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103398784A (en) * | 2013-07-26 | 2013-11-20 | 江苏物联网研究发展中心 | Self-rectification circuit for infrared thermopile temperature sensor |
| CN103398784B (en) * | 2013-07-26 | 2015-06-10 | 江苏物联网研究发展中心 | Self-rectification circuit for infrared thermopile temperature sensor |
| WO2022142237A1 (en) * | 2020-12-29 | 2022-07-07 | 华润微集成电路(无锡)有限公司 | Predictive-type electronic body temperature thermometer circuit structure implementing temperature compensation |
| US11976986B2 (en) | 2020-12-29 | 2024-05-07 | CRM ICBG (Wuxi) Co., Ltd. | Predictive electronic thermometer circuit structure capable of temperature compensation |
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