CN113758606B - Temperature sensor and temperature measuring equipment - Google Patents
Temperature sensor and temperature measuring equipment Download PDFInfo
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- CN113758606B CN113758606B CN202111197789.0A CN202111197789A CN113758606B CN 113758606 B CN113758606 B CN 113758606B CN 202111197789 A CN202111197789 A CN 202111197789A CN 113758606 B CN113758606 B CN 113758606B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K13/00—Thermometers specially adapted for specific purposes
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K15/00—Testing or calibrating of thermometers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
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Abstract
The invention provides a temperature sensor, which comprises a self-detection unit, a current source unit and an analog-to-digital conversion unit, wherein the current source unit is connected with the analog-to-digital conversion unit; the self-detection unit is connected with the current source unit through a self-detection switch, and comprises a first self-detection current source and a second self-detection current source, wherein the first self-detection current source and the second self-detection current source are used for enabling the analog-to-digital conversion unit to output a second quantized output value, and the second quantized output value is used for detecting whether the temperature sensor fails. The self-detection unit is arranged, the self-detection function of the current type temperature sensor is realized, the self-detection unit is simple in structure, small in occupied chip area, low in cost, high in self-detection accuracy and high in stability. The self-detection unit is accurate and stable in self-detection of the temperature sensor, and the accuracy of the self-detection of the temperature sensor is improved. The invention also provides temperature measuring equipment comprising the temperature sensor.
Description
Technical Field
The invention relates to the technical field of temperature detection, in particular to a temperature sensor and temperature measuring equipment.
Background
With the development of integrated circuit technology, the feature size of the process is continuously reduced, the integration level of the chip is continuously improved, the power consumption density of the chip is also higher and higher, and besides the heat dissipation and low power consumption design, the temperature monitoring becomes an indispensable basic function. For analog circuits, many circuit modules and functions are more sensitive to temperature changes, so it is necessary to change the operating configuration in real time according to changes in chip temperature. In addition, in an application scenario requiring high reliability, the temperature sensor circuit is required to have a self-detection function to detect whether the temperature sensor itself fails. And when the circuit failure is detected, timely feeding back the result.
The temperature range detected by the temperature sensor is large, and is usually-40-155 ℃, and the self-detection of the temperature sensor is required to confirm whether the working state of the temperature sensor is normal or not under an unknown temperature condition. This requires the temperature sensor to output a quantized output value that is independent of temperature changes during the self-test mode, and if the quantized output value is within the expected range, the temperature sensor is considered to be currently in a normal operating state, otherwise the temperature sensor is considered to be currently in a failure state. The fixed quantized output value in the self-test mode is required to fall within the expected range as stably as possible, and the expected value range should be as small as possible, especially in the self-test of the high-precision temperature sensor.
In the prior art, an additional detection circuit or a detection device is added to detect whether the temperature sensor fails or not, and the cost is high.
The invention patent with publication number CN 105651416A discloses a current type temperature sensor circuit, which adopts a current mode to convert negative temperature coefficient voltage output by a reference into negative temperature coefficient current, performs proportional integration with positive temperature coefficient current generated by the reference, compares an integrated voltage value with the reference voltage in a comparator to generate a digital signal, samples the generated digital signal through a digital clock and outputs the digital signal, and simultaneously feeds back and controls an integrated coefficient of the proportional integration, and can calculate the current temperature by calculating the number of high level or low level in unit time of sampling output. The charging and discharging of the integrated circuit are finished by skillfully utilizing the positive temperature coefficient current and the negative temperature coefficient circuit, the testing requirements of different use environments, different parameters of the circuit or different temperature detection ranges are met by adjusting the proportional coefficient and the positive and negative temperature coefficient current operation combination of the integrated circuit, the whole circuit is simple, the physical examination is small, and the multi-point testing requirements can be met. However, the invention does not have a detection circuit, so the invention does not have a self-checking function of the current type temperature sensor circuit, and can not judge whether the current type temperature sensor fails.
Therefore, it is necessary to provide a temperature sensor and a temperature measuring device to solve the above-mentioned problems in the prior art.
Disclosure of Invention
The invention aims to provide a temperature sensor and temperature measuring equipment, which are used for solving the problems that the temperature sensor has no self-checking circuit or the cost of the self-checking circuit is high in the prior art.
In order to achieve the above object, the temperature sensor of the present invention includes a self-detection unit, a current source unit and an analog-to-digital conversion unit, wherein the current source unit is connected with the analog-to-digital conversion unit;
the analog-to-digital conversion unit comprises an integrator, a quantizer and a filter, wherein the output end of the current source unit is connected with the input end of the integrator, the output end of the integrator is connected with the input end of the quantizer, and the output end of the quantizer is connected with the input end of the filter;
the self-checking unit is connected with the current source unit through a self-checking switch, the self-checking unit comprises a first self-checking current source and a second self-checking current source, the positive electrode of the first self-checking current source is connected with the negative electrode of the second self-checking current source, the positive electrode of the second self-checking current source is grounded, the first self-checking current source and the second self-checking current source are used for enabling the analog-digital conversion unit to output a second quantized output value, and the second quantized output value is used for detecting whether the temperature sensor fails or not.
The temperature sensor has the beneficial effects that:
the self-detection unit comprises a first self-detection current source and a second self-detection current source, wherein the first self-detection current source and the second self-detection current source are used for enabling the analog-to-digital conversion unit to output a second quantized output value, and the second quantized output value is used for detecting whether the temperature sensor fails or not, so that the self-detection function of the current type temperature sensor is realized. The self-detection unit has the advantages of simple structure, small occupied chip area, low cost, high self-detection accuracy and high stability. The self-detection unit is accurate and stable in self-detection of the temperature sensor, and the accuracy of the self-detection of the temperature sensor is improved.
Preferably, the current source unit includes a first current source, a first control switch, a second control switch and a second current source, wherein the positive electrode of the first current source is sequentially connected with the first control switch, the second control switch and the negative electrode of the second current source, the positive electrode of the second current source is grounded, and a node between the first control switch and the second control switch is connected with the input end of the integrator.
Further preferably, a node between the first control switch and the second control switch is further connected to one end of the self-checking switch, and the other end of the self-checking switch is connected to a node between the first self-checking current source and the second self-checking current source.
Preferably, when the self-checking switch is turned off, the temperature sensor enters a temperature detection mode;
after the temperature sensor enters a temperature detection mode, the first current source outputs a first temperature current and the second current source outputs a second temperature current to the analog-to-digital conversion unit;
and after the analog-to-digital conversion unit receives the first temperature current and the second temperature current, the first temperature current and the second temperature current are quantized to obtain a first quantized output value, and the first quantized output value is related to the first temperature current and the second temperature current. The self-checking switch has the beneficial effects that when the temperature sensor detects the temperature, the self-checking switch is disconnected, so that the first self-checking current source and the second self-checking current source can not influence the detection process and the result of the temperature sensor, and the stable temperature detection process of the temperature sensor is ensured.
Preferably, when the self-checking switch is closed, the temperature sensor enters a self-checking mode;
after the temperature sensor enters a self-checking mode, the first self-checking current source outputs the first self-checking current, the second self-checking current source outputs the second self-checking current, the first current source outputs a first temperature current and the second current source outputs a second temperature current to the analog-to-digital conversion unit;
the analog-to-digital conversion unit receives the first self-checking current, the second self-checking current, the first temperature current and the second temperature current, and then carries out quantization processing on the first self-checking current, the second self-checking current, the first temperature current and the second temperature current to obtain a second quantized output value;
when the second quantized output value is not related to the first temperature current and the second temperature current, judging that the temperature sensor is effective;
and when the second quantized output value is related to any one of the first temperature current and the second temperature current, judging that the temperature sensor is invalid. The temperature detection mode or the self-detection mode of the temperature sensor is flexibly switched according to the requirement, and when the temperature detection is required, the self-detection switch is disconnected; when self-checking is needed, the self-checking switch is closed, so that the temperature sensor enters a self-checking mode, the mode is switched simply and rapidly, and the self-checking efficiency of the temperature sensor is improved. And whether the temperature sensor fails or not is judged through the second quantized output value, the judging method is rapid and effective, the efficiency of judging whether the temperature sensor fails or not is improved, and the self-checking efficiency of the temperature sensor is further improved.
Further preferably, the first self-test current is the second temperature currentThe second self-checking current is +.>N is a real number other than 0 and 1.
Preferably, the quantizer comprises a comparator, a first feedback signal line, a second feedback signal line and an inverter, wherein the output end of the comparator is connected with the second control switch through the first feedback signal line, a node on the first feedback signal line is connected with the input end of the inverter, and the output end of the inverter is connected with the first control switch through the second feedback signal line;
the comparator outputs a result and feeds back the result to the second control switch and the first control switch to control the second control switch and the first control switch respectively.
Preferably, the integrator comprises an operational amplifier, a capacitor and a reset switch, wherein the negative input end of the operational amplifier is connected with a node between the first control switch and the second control switch, the positive input end of the operational amplifier is connected with the positive input end of the comparator, and the output end of the operational amplifier is connected with the negative input end of the comparator;
and two ends of the reset switch are respectively connected with the negative input end of the operational amplifier and the output end of the operational amplifier, and the capacitor is connected with the reset switch in parallel.
Further preferably, the integrator further comprises a voltage source, wherein the positive electrode of the voltage source is connected with the positive input end of the operational amplifier and the positive input end of the comparator, and the negative electrode of the voltage source is grounded.
The invention also provides temperature measuring equipment comprising the temperature sensor.
The temperature measuring equipment has the beneficial effects that:
the temperature measuring equipment comprises the temperature sensor, and the self-detection function of the current type temperature sensor is realized.
Drawings
FIG. 1 is a circuit diagram of a temperature sensor according to an embodiment of the present invention;
fig. 2 is a circuit diagram of a bandgap reference voltage source according to an embodiment of the invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. Unless otherwise defined, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. As used herein, the word "comprising" and the like means that elements or items preceding the word are included in the element or item listed after the word and equivalents thereof without precluding other elements or items.
Aiming at the problems existing in the prior art, the embodiment of the invention provides a temperature sensor and temperature measuring equipment.
Fig. 1 is a circuit diagram of a temperature sensor according to the present invention, referring to fig. 1, the temperature sensor according to the present invention includes a self-detection unit 2, a current source unit 3, and an analog-to-digital conversion unit 1, wherein the current source unit 3 is connected to the analog-to-digital conversion unit 1;
the analog-to-digital conversion unit 1 comprises an integrator 4, a quantizer 5 and a filter 6, wherein the output end of the current source unit 3 is connected with the input end of the integrator 4, the output end of the integrator 4 is connected with the input end of the quantizer 5, and the output end of the quantizer 5 is connected with the input end of the filter 6;
in some embodiments, the filter 6 may be a downsampling filter.
The self-detection unit 2 is connected with the current source unit 3 through the self-detection switch 22, the self-detection unit 2 comprises a first self-detection current source 20 and a second self-detection current source 21, the anode of the first self-detection current source 20 is connected with the cathode of the second self-detection current source 21, the anode of the second self-detection current source 21 is grounded, the first self-detection current source 20 and the second self-detection current source 21 are used for enabling the analog-digital conversion unit 1 to output a second quantized output value, and the second quantized output value is used for detecting whether the temperature sensor fails or not.
The temperature sensor of the invention has the advantages that:
the self-detection unit 2 is provided and comprises a first self-detection current source 20 and a second self-detection current source 21, wherein the first self-detection current source 20 and the second self-detection current source 21 are used for enabling the analog-digital conversion unit 1 to output a second quantized output value, and the second quantized output value is used for detecting whether the temperature sensor fails or not, so that the self-detection function of the current type temperature sensor is realized. The self-detection unit 2 has the advantages of simple structure, small occupied chip area, low cost, high self-detection accuracy and high stability. The self-detection unit 2 is accurate and stable in self-detection of the temperature sensor, and improves the accuracy of the self-detection of the temperature sensor.
As a preferred embodiment of the present invention, the current source unit 3 includes a first current source 30, a first control switch 31, a second control switch 32, and a second current source 33, wherein the positive electrode of the first current source 30 is sequentially connected to the negative electrodes of the first control switch 31, the second control switch 32, and the second current source 33, the positive electrode of the second current source 33 is grounded, and a node between the first control switch 31 and the second control switch 32 is connected to the input terminal of the integrator 4.
As a preferred embodiment of the present invention, the node between the first control switch 31 and the second control switch 32 is further connected to one end of the self-checking switch 22, and the other end of the self-checking switch 22 is connected to the node between the first self-checking current source 20 and the second self-checking current source 21.
As a preferred embodiment of the present invention, when the self-test switch 22 is turned off, the temperature sensor enters a temperature detection mode;
after the temperature sensor enters the temperature detection mode, the first current source 30 outputs a first temperature current and the second current source 33 outputs a second temperature current to the analog-to-digital conversion unit 1; the current value of the first temperature current is I PTAT The current value of the second temperature current is I CTAT ；
After receiving the first temperature current and the second temperature current, the analog-to-digital conversion unit 1 performs quantization processing on the first temperature current and the second temperature current to obtain a first quantized output value. The expression of the first quantized output value mu is
From the above expression of the first quantized output value μ, the first quantized output value μ and the first temperature current I PTAT And the second temperature current.
This has the advantage that when the temperature sensor detects a temperature, the self-checking switch 22 is turned off so that the first and second self-checking current sources 20 and 21 do not affect the temperature sensor detection process and result, ensuring a stable temperature detection process of the temperature sensor.
As a preferred embodiment of the present invention, when self-test switch 22 is closed, the temperature sensor enters a self-test mode;
after the temperature sensor enters the self-checking mode, the first self-checking current source 20 outputs a first self-checking current, the second self-checking current source 21 outputs a second self-checking current, the first current source 30 outputs a first temperature current, and the second current source 33 outputs a second temperature current to the analog-to-digital conversion unit 1;
the analog-to-digital conversion unit 1 receives the first self-checking current, the second self-checking current, the first temperature current and the second temperature current, and then carries out quantization processing on the first self-checking current, the second self-checking current, the first temperature current and the second temperature current to obtain a second quantized output value;
when the second quantized output value is not related to the first temperature current and the second temperature current, judging that the temperature sensor is effective;
when the second quantized output value is correlated with any one of the first temperature current and the second temperature current, it is determined that the temperature sensor is failed. The temperature detection mode or the self-detection mode of the temperature sensor is flexibly switched according to the requirement, and when the temperature detection is required, the self-detection switch 22 is turned off; when self-checking is needed, the self-checking switch 22 is closed, so that the temperature sensor enters a self-checking mode, and the self-checking efficiency of the temperature sensor is improved due to the fact that the mode is switched simply and quickly. And whether the temperature sensor fails or not is judged through the second quantized output value, the judging method is rapid and effective, the efficiency of judging whether the temperature sensor fails or not is improved, and the self-checking efficiency of the temperature sensor is improved.
As the inventionIn a preferred embodiment, the first self-test current is a second temperature currentThe second self-checking current is +.>N is a real number other than 0 and 1.
The advantages are that: outputting a first self-test current through the first self-test current source 20The second self-checking current source 21 outputs a second self-checking current +.>Therefore, the temperature sensor outputs a quantized output value which is irrelevant to the temperature current, and the self-detection function of the temperature sensor is realized.
In some embodiments, after the temperature sensor enters the self-test mode, the first current source 30 outputs a first temperature current having a current value I PTAT The second current source 33 outputs a second temperature current having a current value I CTAT The first self-checking current source 20 outputs a first self-checking current with a current value ofThe second self-checking current source 21 outputs a second self-checking current with a current value of +.>N is a real number other than 0 and 1. The temperature sensor outputs a second quantized output value, and the expression of the second quantized output value mu' is
The right-hand score of the expression of the quantized output value is simplified by the numerator and denominator,
the expression of the second quantized output value is derived from the second quantized output value mu and the first temperature current I CTAT And a second temperature current I CTAT Are not correlated, thereby realizing the self-detection function of the temperature sensor.
As a preferred embodiment of the present invention, referring to fig. 1, the quantizer 5 includes a comparator 50, a first feedback signal line 51, a second feedback signal line 52, and an inverter 53, wherein an output terminal of the comparator 50 is connected to the second control switch 32 through the first feedback signal line 51, a node on the first feedback signal line 51 is connected to an input terminal of the inverter 53, and an output terminal of the inverter 53 is connected to the first control switch 31 through the second feedback signal line 52;
the comparator 50 outputs the result and feeds back to the second control switch 32 and the first control switch 31 to control the second control switch 32 and the first control switch 31, respectively.
As a preferred embodiment of the present invention, referring to fig. 1, the integrator 4 includes an operational amplifier 40, a capacitor 41 and a reset switch 42, wherein a negative input terminal of the operational amplifier 40 is connected to a node between the first control switch 31 and the second control switch 32, the capacitor 41 is connected in series between the negative input terminal of the operational amplifier 40 and an output terminal of the operational amplifier 40, a positive input terminal of the operational amplifier 40 is connected to a positive input terminal of the comparator 50, an output terminal of the operational amplifier 40 is connected to a negative input terminal of the comparator 50, and the capacitor 41 is connected in parallel with the reset switch 42.
As a preferred embodiment of the present invention, referring to fig. 1, the integrator 4 further includes a voltage source 43, wherein a positive electrode of the voltage source 43 is connected to a positive input terminal of the operational amplifier 40 and a positive input terminal of the comparator 50, and a negative electrode of the voltage source 43 is grounded.
In order to better understand the working principle of the temperature sensor of the present invention, the working principle of the temperature sensor of the present invention is described below in conjunction with the working principles of the voltage type temperature sensor and the current type temperature sensor.
The voltage type temperature sensor comprises a band-gap reference voltage source and an analog-to-digital converter, wherein the band-gap reference voltage source is connected with the analog-to-digital converter and used for providing voltage for the analog-to-digital converter, and the analog-to-digital converter is used for outputting a quantized output value proportional to temperature. Fig. 2 is a circuit diagram of a bandgap reference voltage source, as shown in fig. 2, the bandgap reference voltage source 8 includes a start-up circuit 80, an output end of the start-up circuit 80 is connected to a drain electrode of a first PMOS tube PM1 and a first resistor R1, a first end of the first resistor R1 is connected to the drain electrode of the first PMOS tube PM1, a second end of the first resistor R1 is connected to an emitter electrode of a first triode Q1, a collector electrode of the first triode Q1 is connected to a common ground terminal VSS, and a base electrode of the first triode Q1 is shorted to the collector electrode; the source electrode of the first PMOS tube PM1 is connected with the power supply voltage end VDD, and the grid electrode of the first PMOS tube PM1 is connected with the grid electrode of the second PMOS tube PM 2;
the source electrode of the second PMOS tube PM2 is connected with a power supply voltage end VDD, the drain electrode of the second PMOS tube PM2 is connected with the emitter electrode of the second triode Q2, the collector electrode of the second triode Q2 is connected with a common ground end VSS, and the base electrode of the second triode Q2 is in short circuit with the collector electrode;
the node x between the first end of the first resistor R1 and the drain electrode of the first PMOS tube PM1 is also connected with the positive input end of the first operational amplifier 81, the negative input end of the first operational amplifier 81 is connected with the node y between the drain electrode of the second PMOS tube PM2 and the emitter electrode of the second triode Q2, the output end of the first operational amplifier 81 is connected with the grid electrode of the first PMOS tube PM1 and the grid electrode of the second PMOS tube PM2, the output end of the first operational amplifier 81 is also connected with the grid electrode of the third PMOS tube PM3 and the grid electrode of the fourth PMOS tube PM4, the source electrode of the third PMOS tube PM3 and the source electrode of the fourth PMOS tube PM4 are both connected with the power supply voltage end VDD, and the drain electrodes of the second PMOS tube PM2, the third PMOS tube PM3 and the fourth PMOS tube PM4 all output currents I PTAT ；
The drain electrode of the third PMOS tube PM3 is connected with the first end of the second resistor R2, a voltage output end VREF is connected between the drain electrode of the third PMOS tube PM3 and the first end of the second resistor R2, the second end of the second resistor R2 is connected with the emitter electrode of the third triode Q3, the collector electrode of the third triode Q3 is connected with the common ground end VSS, and the base electrode and the collector electrode of the third triode Q3 are short-circuited; the second end of the second resistor R2 and the emitter of the third triode Q3 are connected with the positive input end of the second operational amplifier 82, the negative input end of the second operational amplifier 82 is connected with the first end of the third resistor R3, the second end of the third resistor R3 is connected with the common ground end VSS, the output end of the second operational amplifier 82 is connected with the grid electrode of the NMOS tube NM1, the source electrode of the NMOS tube NM1 is connected with the first end of the third resistor R3 and the negative input end of the second operational amplifier 82, and the drain electrode of the NMOS tube NM1 outputs current ICTAT. Since the working principle of the bandgap reference voltage source 8 is a common technical means in the art, the description thereof will not be repeated here.
Output voltage V of bandgap reference voltage source 8 REF The expression of (2) is as follows:
ΔV BE ＝V T ln(N)
wherein V is REF Is the output voltage of the voltage output terminal VREF, namely the output voltage of the band-gap reference voltage source 8, V BE For the emitter voltage of the third transistor Q3, deltaV BE Is of negative temperature coefficient characteristic, R 1 Is the resistance value corresponding to the first resistor R1, R 2 The resistance value V is the resistance value corresponding to the second resistor R2 T For the thermal voltage with positive temperature coefficient characteristic, N is the number ratio of the first triode Q1 to the second triode Q2, V PTAT The input signal voltage provided to the analog-to-digital converter for the bandgap reference voltage source. In the above expression, the negative temperature coefficient and the positive temperature coefficient characteristic voltage superposition are actually used to generate the output voltage V with approximately zero temperature coefficient REF 。
Voltage V of the band gap reference voltage source PTAT As input signal to the analog-to-digital converter, voltage V PTAT Proportional to absolute temperature. Output voltage V of the voltage output terminal REF As a reference voltage for the analog-to-digital converter, the output voltage V REF Approximately zero temperature coefficient characteristics. The expression of the quantization result of the analog-to-digital converter is:
the quantized output value mu is obtained, and the quantized output value mu is proportional to the temperature, so that the temperature detection function of the temperature sensor is realized.
The pair of expressions for the output voltage of the bandgap reference voltage source 8 according to the abovePerforming deformation treatment, wherein the deformed expression is as follows:
make the following stepsBoth the numerator and denominator of the fraction to the right of the expression are divided by R 3 ，R 3 And obtaining an expression for the resistance value corresponding to the third resistor R3:
let R 3 ＝R 2 Obtaining
Then according to ohm's law, can obtain
Wherein I is PTAT The first temperature current generated by the band-gap reference voltage source 8, namely the current output by the drain electrode of the fourth PMOS tube PM4, is used as the first input current of the analog-to-digital converter; i CTAT The second temperature current generated for the bandgap reference voltage source 8, i.e. the current output by the drain of the NMOS transistor NM1, is used as the second input current for the analog-to-digital converter.
Will beSubstituted into->The expression is obtained:
it can be seen that toConverting a relation equation of quantized output value and voltage into a relation equation of quantized output value and current, namely converting an input of an analog-to-digital converter from a voltage signal to a current signal, thereby obtaining an expression of quantized output value of a current-type temperature sensor
Referring to fig. 1, the temperature sensor of the present invention operates as follows:
(1) When the temperature sensor is in the temperature detection mode, the self-checking switch 22 is opened, the first control switch 31 is closed, and the second control switch 32 is opened, the first current source 30 outputs a first temperature current to the integrator 4, and the current value of the first temperature current is I PTAT The method comprises the steps of carrying out a first treatment on the surface of the The first control switch 31 is turned offWhen the second control switch 32 is turned on, the second current source 33 outputs a second temperature current to the integrator 4, the second temperature current having a current value I CTAT ；
Illustratively, a first temperature current I PTAT And a second temperature current I CTAT May be provided by the bandgap reference voltage source described above.
After receiving the first temperature current and the second temperature current, the integrator 4 performs an integration operation on the first temperature current and the second temperature current to obtain an integrated voltage, and outputs the integrated voltage to the comparator 50;
the comparator 50 compares the integrated voltage with a preset reference voltage, and the comparator 50 outputs a logic value "1" or "0" to the filter 6 according to the comparison result;
the filter 6 counts the number of the logical values of "1" in a preset time period, calculates the duty ratio of the number of the logical values of "1" in all the logical values received by the filter 6 in the time region, and outputs the digital word code according to the duty ratio of the number of the logical values of "1". The output digital code is the first quantized output value, the first quantized output value and the first temperature current I PTAT And a second temperature current I CTAT All in relation, the first quantized output value is proportional to the detected temperature. In the temperature detection mode, the first quantized output value μ of the temperature sensor is expressed as
It should be noted that, since the output end of the comparator 50 is further connected to the first control switch 31 and the second control switch 32 through the feedback module 7, when the comparator 50 outputs the logic value "1" or "0" to the filter 6, the comparator 50 also feeds back the logic value "1" or "0" to the first control switch 31 and the second control switch 32 to control the on/off of the first control switch 31 and the second control switch 32.
Specifically, when the comparator 50 outputs the logic value "1", the logic value "1" is transmitted to the second control switch 32 through the first feedback signal line 51, and after the second control switch 32 receives the logic value "1", the second control switch 32 is closed and turned on; after the logic value "1" on the first feedback signal line 51 is input into the inverter 53, the inverter 53 outputs the logic value "0", and transmits the logic value "0" to the first control switch 31 through the second feedback signal line 52, and after the first control switch 31 receives the logic value "0", the first control switch 31 is turned off;
when the comparator 50 outputs the logic value "0", the second control switch 32 is turned off after the second control switch 32 receives the logic value "0"; the first control switch 31 receives the logic value "1" output from the inverter 53, and the first control switch 31 is closed and turned on.
It should be noted that, in the temperature detection mode or the self-detection mode, the switch states of the first control switch 31 and the second control switch 32 of the current-type temperature sensor are always opposite, that is, when the first control switch 31 is closed, the second control switch 32 is opened; when the first control switch 31 is opened, the second control switch 32 is closed.
(2) The self-detecting unit 2 is configured to detect whether the current temperature sensor circuit can normally operate, and if the current ambient temperature is unknown in the self-detecting mode, that is, the output of the current temperature sensor that can normally detect the temperature should not be affected by a temperature factor in the self-detecting mode, so that the quantized output value of the output of the current temperature sensor must be a predetermined value that is independent of the temperature and is determined to be used for determining that the current temperature sensor has not failed.
The self-checking working principle of the temperature sensor is as follows:
when the temperature sensor is in the self-checking mode, the self-checking switch 22 is closed, so that the first self-checking current source 20 and the second self-checking current source 21 are connected into a current type temperature sensor circuit, and the temperature sensor enters the self-checking mode;
the self-checking switch 22 is closed, the first self-checking current source 20 outputs a first self-checking current to the integrator 4, and the current value of the first self-checking current is thatSecond self-checking currentSource 21 outputs a second self-test current to integrator 4, the second self-test current having a current value of +.>When the first control switch 31 is closed and the second control switch 32 is opened, the first current source 30 outputs a first temperature current to the integrator 4, the first temperature current having a current value I PTAT The method comprises the steps of carrying out a first treatment on the surface of the When the first control switch 31 is opened and the second control switch 32 is closed, the second current source 33 outputs a second temperature current to the integrator 4, and the current value of the second temperature current is I CTAT ；
After receiving the first temperature current, the second temperature current, the first self-checking current and the second self-checking current, the integrator 4 performs an integration operation on the first temperature current, the second temperature current, the first self-checking current and the second self-checking current to obtain an integrated voltage, and outputs the integrated voltage to the comparator 50;
the comparator 50 compares the integrated voltage with a predetermined reference voltage, and the comparator 50 outputs a logic value "1" or "0" to the filter 6 according to the comparison result. The filter 6 counts the number of logical values of "1" in a preset time period, calculates the duty ratio of the number of logical values of "1" in all logical values received by the filter 6 in the time region, and outputs the digital character code according to the duty ratio. The output digital code is the quantized output value.
In the self-checking mode of the temperature sensor, the expression of the second quantized output value mu' of the temperature sensor is
Where N is a real number other than 0 and 1.
Simplifying the expression to obtain
From the above expression of the second quantized output value, when the temperature sensor is active, the second quantized output value μ' is expressedWith a first temperature current I PTAT And a second temperature current I CTAT And is irrelevant, so that a fixed second quantized output value which is irrelevant to temperature is obtained, and the self-detection function of the temperature sensor is realized.
Those skilled in the art will appreciate that the embodiments described herein are intended to aid the reader in understanding the principles of the present invention. Various other specific modifications and combinations can be made by the designer in light of the teachings of the present disclosure without departing from the spirit of the invention, and such modifications and combinations remain within the scope of the invention.
Illustratively, any source of current based on positive and negative temperature, e.g. output current I as a source of positive temperature PTAT Output current value I of negative temperature current source CTAT The current type temperature sensor for input signals can be designed by the invention, so that the function of self-detection is realized. Including but not limited to ramp type temperature sensors or higher order multi-bit quantized Delta Sigma modulators, etc.
The invention also provides temperature measuring equipment comprising the temperature sensor.
The temperature measuring device of the invention has the advantages that:
the temperature sensor arranged by the temperature measuring equipment is simple in structure, and the temperature current in the quantized output value output by the current type temperature sensor is eliminated through the current output by the self-checking current source, so that the current type temperature sensor outputs a quantized output value which is irrelevant to the temperature current, the self-checking purpose of the temperature sensor is achieved, the self-checking of the temperature type sensor is completed, and the self-checking function of the temperature sensor is realized.
The temperature sensor and the temperature measuring equipment provided by the invention can be used for detecting whether the temperature sensor circuit fails or not, and can be used for application scenes with high reliability requirements, such as military industry, vehicle-mounted scenes and the like.
While embodiments of the present invention have been described in detail hereinabove, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. It is to be understood that such modifications and variations are within the scope and spirit of the present invention as set forth in the following claims. Moreover, the invention described herein is capable of other embodiments and of being practiced or of being carried out in various ways.
Claims (7)
1. The temperature sensor is characterized by comprising a self-detection unit, a current source unit and an analog-to-digital conversion unit, wherein the current source unit is connected with the analog-to-digital conversion unit;
the analog-to-digital conversion unit comprises an integrator, a quantizer and a filter, wherein the output end of the current source unit is connected with the input end of the integrator, the output end of the integrator is connected with the input end of the quantizer, and the output end of the quantizer is connected with the input end of the filter;
the self-detection unit is connected with the current source unit through a self-detection switch, the self-detection unit comprises a first self-detection current source and a second self-detection current source, the positive electrode of the first self-detection current source is connected with the negative electrode of the second self-detection current source, the positive electrode of the second self-detection current source is grounded, the first self-detection current source and the second self-detection current source are used for enabling the analog-to-digital conversion unit to output a second quantized output value, and the second quantized output value is used for detecting whether the temperature sensor fails or not;
the current source unit comprises a first current source, a first control switch, a second control switch and a second current source, wherein the positive electrode of the first current source is sequentially connected with the negative electrodes of the first control switch, the second control switch and the second current source, the positive electrode of the second current source is grounded, and a node between the first control switch and the second control switch is connected with the input end of the integrator;
the node between the first control switch and the second control switch is also connected with one end of the self-checking switch, and the other end of the self-checking switch is connected with the node between the first self-checking current source and the second self-checking current source;
when the self-checking switch is disconnected, the temperature sensor enters a temperature detection mode; after the temperature sensor enters a temperature detection mode, the first current source outputs a first temperature current and the second current source outputs a second temperature current to the analog-to-digital conversion unit;
when the self-checking switch is closed, the temperature sensor enters a self-checking mode; after the temperature sensor enters a self-checking mode, the first self-checking current source outputs the first self-checking current, the second self-checking current source outputs the second self-checking current, the first current source outputs a first temperature current and the second current source outputs a second temperature current to the analog-to-digital conversion unit;
the first self-checking current is the second temperature currentThe second self-checking current is multiple of the first temperature currentN is a real number other than 0 and 1.
2. The temperature sensor of claim 1, wherein the analog-to-digital conversion unit receives the first temperature current and the second temperature current, and then quantizes the first temperature current and the second temperature current to obtain a first quantized output value, and the first quantized output value is related to both the first temperature current and the second temperature current.
3. The temperature sensor of claim 2, wherein the analog-to-digital conversion unit receives the first self-test current, the second self-test current, the first temperature current, and the second temperature current, and then quantizes the first self-test current, the second self-test current, the first temperature current, and the second temperature current to obtain the second quantized output value;
when the second quantized output value is not related to the first temperature current and the second temperature current, judging that the temperature sensor is effective;
and when the second quantized output value is related to any one of the first temperature current and the second temperature current, judging that the temperature sensor is invalid.
4. The temperature sensor of claim 1, wherein the quantizer comprises a comparator, a first feedback signal line, a second feedback signal line, and an inverter, an output of the comparator being connected to the second control switch through the first feedback signal line, a node on the first feedback signal line being connected to an input of the inverter, an output of the inverter being connected to the first control switch through the second feedback signal line;
the comparator outputs a result and feeds back the result to the second control switch and the first control switch to control the second control switch and the first control switch respectively.
5. The temperature sensor of claim 4, wherein the integrator comprises an operational amplifier, a capacitor and a reset switch, wherein a negative input terminal of the operational amplifier is connected to a node between the first control switch and the second control switch, a positive input terminal of the operational amplifier is connected to a positive input terminal of the comparator, and an output terminal of the operational amplifier is connected to a negative input terminal of the comparator;
and two ends of the reset switch are respectively connected with the negative input end of the operational amplifier and the output end of the operational amplifier, and the capacitor is connected with the reset switch in parallel.
6. The temperature sensor of claim 5, wherein the integrator further comprises a voltage source having a positive terminal connected to the positive input of the operational amplifier and the positive input of the comparator, and a negative terminal connected to ground.
7. A temperature measuring device comprising a temperature sensor according to any one of claims 1 to 6.
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| CN112115520B (en) * | 2020-09-18 | 2024-06-07 | 天津兆讯电子技术有限公司 | Internal power supply structure and method, security chip and electronic card |
| CN112069554B (en) * | 2020-09-18 | 2024-06-11 | 天津兆讯电子技术有限公司 | External power supply power-on structure and method thereof, security chip and electronic card |
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