TWI691709B - Thermal radiation temperature measurement system - Google Patents

Abstract

A thermal radiation temperature measurement system includes a thermoelectric element, a detection switch module coupled with the first endpoint of the thermoelectric element, and a central processing module coupled with the first and second endpoints of the thermoelectric element and the detection switch module. The detection switch module, according to the operation signal from the central processing module, controls the thermoelectric element to be in a first or second measurement mode. In the first measurement model, a first temperature signal is generated based on the voltage difference between the first and second endpoints. In the second measurement mode, the thermoelectric element measures the environmental temperature to generate a second temperature signal. By switching the thermoelectric element between the two temperature measurement modes, the cost for thermistor installation and the chip area are reduced.

Description

Thermal radiation temperature measurement system

The invention relates to a measurement system, in particular to a thermal radiation temperature measurement system using thermoelectric elements to detect the temperature of objects and the environment.

Press, the thermopile sensor can be used to measure the temperature of the target, and the sensing chip of the thermopile sensor is mainly composed of a thermopile and a thermistor, in which the thermopile absorbs the infrared generated by the target due to the temperature The relative temperature signal generated by the energy and the ambient temperature around the thermopile are measured by the thermistor.

However, the thermistor is set around the thermopile. The detected ambient temperature is not the ambient temperature of the thermopile itself, but the ambient temperature around the thermopile. Therefore, the measured temperature There are still doubts about accuracy.

In addition, in addition to the area of the thermopile and thermistor, the sensing chip of the thermopile sensor needs to be additionally equipped with a thermistor and a connecting wire to obtain the signal of the thermistor, which will increase Sensing the overall area and manufacturing cost of the wafer.

In order to solve the above-mentioned problems, the present invention provides a thermal radiation temperature measurement system that controls thermoelectric elements to perform temperature measurement in two modes through a detection switching module, so as to effectively improve the measurement accuracy and reduce the cost of installing the thermistor And shrink the wafer area.

An embodiment of the present invention provides a thermal radiation temperature measurement system, which includes: a thermoelectric element, a detection switching module, and a central processing module. The thermoelectric element has a first end point and a second end point ; The detection switching module is coupled to the first end of the thermoelectric element; the central processing module is coupled to the first end and the second end of the thermoelectric element and the detection switching module, the central processing module outputs a control The signal to the detection switching module, the detection switching module controls the thermoelectric element to a first measurement mode or a second measurement mode according to the control signal, wherein, during the first measurement mode, the thermoelectric The voltage difference between the first terminal and the second terminal of the device to generate a first temperature signal, the central processing module receives the first temperature signal; in the second measurement mode, by the resistance value of the thermoelectric element The ambient temperature is measured by changes to generate a second temperature signal. The central processing module receives the second temperature signal; the central processing module calculates the actual temperature of the target object based on the first temperature signal and the second temperature signal.

Through the above, the present invention controls the thermoelectric element through the detection switching module to perform temperature measurement in two modes; thereby, avoiding the detection of the ambient temperature around the non-thermoelectric element itself, causing the temperature error of the measured target To ensure the accuracy of temperature detection.

Furthermore, the present invention does not require additional thermistors, and only needs to control the thermoelectric elements to detect the temperature of the two modes by detecting the switching mode; thereby, the system cost can be effectively reduced, and the chip area can be reduced and the manufacturing quality can be improved. rate.

In one embodiment, the central processing module has a controller and a signal converter, the controller outputs a control signal; the signal converter receives and converts the first temperature signal and the second temperature signal and sends it to the controller; wherein, The controller has a time unit, and the time unit sets the output time of the control signal; the controller divides the first measurement mode into a first delay state and a first detection state according to the output time of the control signal set by the time unit. And the second measurement mode is divided into a second delay state and a second detection state. In this way, the present invention controls the thermoelectric element to perform a delayed state before entering the detection state, so as to prevent the thermoelectric element from performing temperature measurement in an unstable state, so that the thermoelectric element generates an unstable temperature change signal; thereby, the thermoelectric element can be avoided The noise output by the component affects the accuracy of the subsequent detection, thereby improving the measurement accuracy of the present invention.

In one of the embodiments, the present invention further has an amplifier, which is coupled to the thermoelectric element, the central processing module and the detection switching module; thereby, the amplifier of the present invention can be used as a signal amplification process and control the thermoelectric element The dual effect of status.

In order to facilitate the description of the central idea of the present invention in the column of the above summary of the invention, it is expressed in a specific embodiment. In the embodiments, various objects are drawn according to the proportion, size, deformation or displacement suitable for description, rather than drawn according to the proportion of actual elements, which will be described first.

Please refer to FIG. 1 to FIG. 5, the present invention provides a thermal radiation temperature measurement system 100, which includes: a thermoelectric element 10, a detection switching module 20, a central processing module 30, an amplifier 40 and a The reference voltage module 50, the thermoelectric element 10 are coupled to the detection switching module 20, the central processing module 30, and the amplifier 40, wherein the thermoelectric element 10 is controlled by the detection switching module 20 to perform temperature measurement in two modes .

The thermoelectric element 10 has a first terminal 11 and a second terminal 12. In the embodiment of the present invention, the thermoelectric element 10 is a thermopile.

The detection switching module 20 is coupled to the first terminal 11 of the thermoelectric element 10; in the embodiment of the present invention, the detection switching module 20 is a P-type metal oxide half field effect transistor (PMOS), P-type The source electrode of the MOSFET is coupled to the first terminal 11 of the thermoelectric element 10, the drain electrode of the P-type MOSFET is coupled to the power supply terminal VDD, and the P-type MOSFET The gate is coupled to the central processing module 30, wherein the power supply voltage provided by the power supply terminal VDD is greater than 0 volts. In this embodiment, the power supply terminal VDD provides a power supply voltage of 3.3 volts.

The central processing module 30 is coupled to the first terminal 11 and the second terminal 12 of the thermoelectric element 10 and the detection switching module 20. The central processing module 30 has a controller 31, the controller 31 and the detection The switching module 20 is coupled, and the controller 31 outputs a control signal to the detection switching module 20. The detection switching module 20 controls the thermoelectric element 10 according to the control signal to a first measurement mode or a second measurement mode In the embodiment of the present invention, the control signal is a square wave signal, which is a continuous output of high level voltage (1/HIGH) and low level voltage (0/LOW), wherein, when the control signal is high level When the voltage is high, it detects that the switching module 20 is not conductive, and the thermoelectric element 10 is the first measurement mode; when the control signal is a low level voltage, the detection switching module 20 is conductive, and the thermoelectric element 10 is the second Measuring modalities.

During the first measurement mode, it is used to measure the temperature of the target object, wherein a first temperature signal is generated by the voltage difference between the first terminal 11 and the second terminal 12 of the thermoelectric element 10, The first temperature signal is the thermal radiation temperature of the target, and the central processing module 30 receives the first temperature signal; during the second measurement mode, the thermoelectric element 10 performs ambient temperature measurement to generate a second temperature signal , The central processing module 30 receives the second temperature signal; the central processing module 30 calculates the actual temperature of the target object through the first temperature signal and the second temperature signal, that is, the target object is measured by the first temperature signal The heat radiation temperature may be affected by the ambient temperature. Therefore, the central processing module 30 needs to subtract the second temperature signal from the first temperature signal to obtain the actual temperature of the target.

The central processing module 30 has a signal converter 32, which is coupled between the first terminal 11 and the second terminal 12 of the thermoelectric element 10, wherein the signal converter 32 receives and converts the first temperature signal and the second Two temperature signals, and send the converted first temperature signal and second temperature signal to the controller 31; in the embodiment of the present invention, the signal converter 32 is an analog-to-digital converter (ADC) .

Furthermore, the controller 31 has a time unit 311 which is used to set the output time of the control signal. The controller 31 divides the first measurement mode into a first delay state D1 and a first detection state R1 according to the output time of the control signal set by the time unit 311, and divides the second measurement mode into a first The second delay state D2 and a second detection state R2, wherein, in the first detection state R1, the thermoelectric element 10 is used to measure the thermal radiation temperature of the target; in the second detection state R2, the thermoelectric element 10 is used to measure the ambient temperature.

Please refer to FIGS. 1 and 5. In the first measurement mode, the controller 31 first controls the thermoelectric element 10 to perform the first delay state D1, and then performs the first detection state R1; in the second measurement mode At this time, the controller 31 first controls the thermoelectric element 10 to perform the second delay state D2, and then performs the second detection state R2; wherein the purpose of the first delay state D1 and the second delay state D2 is to prevent the thermoelectric element 10 from directly entering the second During a detection state R1 or a second detection state R2, the signal oscillation is unstable and the thermoelectric element 10 outputs an unstable signal.

The time unit 311 has a first delay time corresponding to the first delay state D1, the time unit 311 has a first detection time corresponding to the first detection state R1, and the time unit 311 has a second delay time corresponding to the second delay state D2. The time unit 311 has a second detection time corresponding to the second detection state R2. The second delay time is different from the first delay time, and the second detection time is different from the first detection time. The second delay time is shorter than The first delay time, the second detection time is shorter than the first detection time, the first delay time is shorter than the first detection time, and the second delay time is shorter than the second detection time. In the embodiment of the present invention, the first One detection time is 8.8 seconds, the second detection time is 1.8 seconds, the first delay time is 0.9 seconds, and the second delay time is 0.2 seconds; and the overall time of the first measurement mode is longer than that of the second measurement mode The overall time is intended to mean that the ambient temperature is more stable than the thermal radiation temperature of the target, so when the thermoelectric element 10 detects the thermal radiation temperature of the target in the first measurement mode, it can be switched to The second measurement mode confirms the current ambient temperature change of the thermoelectric element 10 to ensure the accuracy of measuring the actual temperature of the target object.

The amplifier 40 is coupled to the signal converter 32 of the thermoelectric element 10, the detection switching module 20 and the central processing module 30, wherein the positive end of the amplifier 40 and the first end point 11 of the thermoelectric element 10 and the detection switch The module 20 is coupled. The negative terminal of the amplifier 40 is coupled to the reference voltage module 50 and the second terminal 12 of the thermoelectric element 10. The output terminal of the amplifier 40 is coupled to the signal converter 32 of the central processing module 30.

The reference voltage module 50 is used to output a reference voltage to the thermoelectric element 10 and the amplifier 40. In the embodiment of the present invention, the reference voltage module 50 has a first resistor 51 and a second resistor 52. The first resistor 51 and The second resistor 52 is arranged in series between the power terminal VDD and the ground. The first resistor 51 and the second resistor 52 divide the power voltage provided by the power terminal VDD to output the reference voltage.

Please refer to FIG. 2, FIG. 3 and FIG. 5, when the control signal output by the controller 31 is a high level voltage, the detection switching module 20 cannot be turned on, so the thermoelectric element 10 is controlled as the first measurement mode, At this time, the controller 31 first controls the thermoelectric element 10 to perform the first delay state D1, and then performs the first detection state R1 to allow the thermoelectric element 10 to sense the thermal radiation of the target, and then the thermoelectric element 10 will generate a temperature voltage Therefore, there will be a small signal difference (voltage difference) between the first terminal 11 and the second terminal 12 of the thermoelectric element 10. This small signal difference is the first temperature signal, and the first temperature signal passes through the amplifier 40. The signal is amplified and output to the signal converter 32, and then the controller 31 receives the first temperature signal.

Please refer to FIG. 2, FIG. 4 and FIG. 5, when the control signal output by the controller 31 is a low level voltage, the detection switching module 20 is turned on, and thus the thermoelectric element 10 is controlled as the second measurement mode. At this time, the controller 31 first controls the thermoelectric element 10 to perform the second delay state D2, and then performs the second detection state R2, and the amplifier 40 will exhibit positive saturation and cannot perform signal amplification. Therefore, the thermoelectric element 10 can be equivalent It is regarded as a variable resistance, and the thermoelectric element 10 will have a resistance change according to the surrounding ambient temperature, so that the reference voltage of the reference voltage module 50 changes accordingly, thereby generating a second temperature signal, and the second temperature signal is output To the signal converter 32, the controller 31 receives the second temperature signal.

In summary, the present invention has the following effects:

1. The thermal radiation temperature measurement system 100 of the present invention can control the thermoelectric element 10 to perform temperature measurement of two modes through the detection switching module 20; thereby, the temperature of the target object is detected by the thermoelectric element 10 itself and The ambient temperature of the thermoelectric element 10 ensures the accuracy of the actual temperature of the target.

2. The thermal radiation temperature measurement system 100 of the present invention does not require additional thermistors, and only needs to control the thermoelectric element 10 through the detection switching module 20 to perform temperature measurement in two modes; thereby, the system cost can be effectively reduced And, can reduce the wafer area and improve manufacturing yield.

3. The thermal radiation temperature measurement system 100 of the present invention can control the thermoelectric element 10 in the first measurement mode or the second measurement mode to perform the delay state before entering the detection state; thereby, the thermoelectricity can be avoided The element 10 outputs noise, which affects the detection accuracy of the connection, thereby improving the measurement accuracy of the present invention.

4. The amplifier 40 of the thermal radiation temperature measurement system 100 of the present invention can be used for signal amplification processing, and the dual function of controlling the thermoelectric element 10 with the detection switching module 20 as two temperature measurement modes.

The above-mentioned embodiments are only used to illustrate the present invention, not to limit the scope of the present invention. Any modifications or changes that do not violate the spirit of the present invention are within the scope of the invention to be protected.

100: thermal radiation temperature measurement system 40: amplifier 10: Thermoelectric element 50: Reference voltage module 11: First endpoint 51: First resistance 12: second endpoint 52: Second resistance 20: Detection switching module D1: First delay state 30: central processing module D2: Second delay state 31: Controller R1: first detection status 311: time unit R2: second detection status 32: Signal converter VDD: power supply endpoint

FIG. 1 is a system architecture diagram of the present invention. 2 is a schematic diagram of an embodiment of the circuit of the present invention. 3 is a schematic diagram of an equivalent circuit of the first measurement mode of the present invention. 4 is a schematic diagram of an equivalent circuit of a second measurement mode of the present invention. 5 is a schematic diagram of the control flow of the time control unit of the present invention.

100: thermal radiation temperature measurement system

10: Thermoelectric element

20: Detection switching module

30: central processing module

31: Controller

311: time unit

32: Signal converter

40: amplifier

50: Reference voltage module

Claims (10)

A thermal radiation temperature measurement system, including: A thermoelectric element having a first end point and a second end point; A detection switching module, which is coupled to the first end of the thermoelectric element; and A central processing module, which is coupled to the first and second end points of the thermoelectric element and the detection switching module, the central processing module outputs a control signal to the detection switching module, the detection The measurement switching module controls the thermoelectric element to be a first measurement mode or a second measurement mode according to the control signal, wherein, during the first measurement mode, the first end of the thermoelectric element is used The voltage difference between the point and the second end point to generate a first temperature signal, the central processing module receives the first temperature signal; during the second measurement mode, the resistance value of the thermoelectric element changes Ambient temperature measurement is performed to generate a second temperature signal, and the central processing module receives the second temperature signal; the central processing module calculates the actual temperature of the target object based on the first temperature signal and the second temperature signal . The thermal radiation temperature measurement system according to claim 1, wherein the central processing module has a controller and a signal converter, the controller outputs the control signal; the signal converter receives and converts the first temperature signal And send the second temperature signal to the controller. The thermal radiation temperature measurement system according to claim 2, wherein the controller has a time unit, and the time unit sets the output time of the control signal. The thermal radiation temperature measurement system according to claim 3, wherein the controller distinguishes the first measurement mode into a first delay state and a first time according to the output time of the control signal set by the time unit A detection state, and distinguish the second measurement mode into a second delay state and a second detection state. The thermal radiation temperature measurement system according to claim 4, wherein during the first measurement mode, the controller first controls the thermoelectric element to perform the first delay state, and then performs the first detection state; During the second measurement mode, the controller first controls the thermoelectric element to perform the second delay state, and then performs the second detection state. The thermal radiation temperature measuring system according to claim 5, wherein the time unit is provided with a first delay time corresponding to the first delay state, and the time unit is provided with a second delay time corresponding to the second delay state; the time The unit has a first detection time corresponding to the first detection state, the time unit has a second detection time corresponding to the second detection state, the second delay time is different from the first delay time, the second The detection time is different from the first detection time. The thermal radiation temperature measurement system according to claim 6, wherein the second delay time is shorter than the first delay time, the second detection time is shorter than the first detection time, and the first delay time is shorter At the first detection time, the second delay time is shorter than the second detection time. The thermal radiation temperature measurement system according to claim 1, wherein the detection switching module is a P-type metal oxide half-field effect transistor, and the source of the P-type metal oxide half-field effect transistor is coupled to the thermoelectric element Then, the drain of the P-type metal-oxide-half field-effect transistor is coupled to the power supply terminal, and the gate of the P-type metal-oxide-half field-effect transistor is coupled to the central processing module. The thermal radiation temperature measurement system according to claim 8 further has an amplifier, which is coupled to the thermoelectric element, the central processing module, and the detection switching module. The thermal radiation temperature measurement system according to claim 9, wherein the positive terminal of the amplifier is coupled to the first terminal of the thermoelectric element and the detection switching module, and the negative terminal of the amplifier is connected to a reference voltage mode And the second end of the thermoelectric element are coupled, and the output end of the amplifier is coupled to the central processing module.

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