CN220418680U - Temperature detection circuit - Google Patents
Temperature detection circuit Download PDFInfo
- Publication number
- CN220418680U CN220418680U CN202322031988.5U CN202322031988U CN220418680U CN 220418680 U CN220418680 U CN 220418680U CN 202322031988 U CN202322031988 U CN 202322031988U CN 220418680 U CN220418680 U CN 220418680U
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- voltage
- resistor
- circuit
- voltage comparator
- comparator
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- 238000001514 detection method Methods 0.000 title claims abstract description 51
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims abstract description 54
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 27
- 239000003990 capacitor Substances 0.000 claims description 11
- 230000009977 dual effect Effects 0.000 claims description 11
- 230000001105 regulatory effect Effects 0.000 claims description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
Abstract
The utility model relates to the technical field of circuits, in particular to a temperature detection circuit, which comprises: the dual-operation amplifier comprises a voltage follower and a voltage comparator; the first voltage dividing circuit comprises a platinum thermal resistor and a first resistor and is used for inputting detection voltage to the voltage follower; the voltage follower is used for providing the detection voltage to the voltage comparator; the reference circuit is used for providing a reference voltage for the voltage comparator; the voltage comparator is used for amplifying the difference value between the first voltage input by the voltage follower and the reference voltage to obtain an output voltage, and sending the output voltage to the singlechip; the singlechip is used for establishing a corresponding relation between the output voltage and the resistance value of the platinum resistor, and detecting the temperature according to the corresponding relation; the utility model can expand the temperature detection range.
Description
Technical Field
The utility model relates to the technical field of circuits, in particular to a temperature detection circuit.
Background
Most household appliances in the related art use an NTC thermistor to detect temperature, and voltage signals are output through the voltage division of the NTC thermistor and are detected by a single chip microcomputer. The temperature range detectable by the NTC thermistor is-40 deg.c to 300 deg.c, and when this temperature range is exceeded, for example, the detection temperature reaches 400 deg.c, the NTC thermistor cannot be used.
Therefore, it is necessary to provide a temperature detection circuit to expand the temperature detection range.
Disclosure of Invention
The utility model aims to provide a temperature detection circuit which can expand a temperature detection range.
In order to achieve the above object, the present utility model provides the following technical solutions:
a temperature detection circuit, comprising:
a dual operational amplifier comprising a voltage follower and a voltage comparator; the output end of the voltage follower is respectively connected with the inverting input end of the voltage follower and the inverting input end of the voltage comparator;
the first voltage dividing circuit comprises a platinum thermal resistor and a first resistor, wherein the first end of the platinum thermal resistor is connected with a power supply end, the second end of the platinum thermal resistor is respectively connected with the positive input end of the voltage follower and one end of the first resistor, and the other end of the first resistor is grounded;
the reference circuit is connected with the non-inverting input end of the voltage comparator;
the first voltage dividing circuit is used for inputting detection voltage to the voltage follower;
the voltage follower is used for providing the detection voltage to the voltage comparator;
the reference circuit is used for providing reference voltage for the voltage comparator;
the voltage comparator is used for amplifying the difference value between the first voltage input by the voltage follower and the reference voltage to obtain an output voltage, and sending the output voltage to the singlechip;
and the singlechip is used for establishing a corresponding relation between the output voltage and the resistance value of the platinum resistor, and detecting the temperature according to the corresponding relation.
Optionally, the reference circuit includes a second resistor and a third resistor; one end of the third resistor is connected with a power supply end, the other end of the third resistor is respectively connected with the normal phase input end of the voltage comparator and one end of the second resistor, and the other end of the second resistor is grounded.
Optionally, the reference circuit further includes a variable resistor, an adjusting end of the variable resistor is connected with a non-inverting input end of the voltage comparator, and the other two ends of the variable resistor are respectively connected between the third resistor and the second resistor.
Optionally, the temperature detection circuit further comprises a second voltage division circuit, wherein the second voltage division circuit comprises a fourth resistor and a fifth resistor; the fourth resistor is connected between the output end of the voltage follower and the inverting input end of the voltage comparator; the fifth resistor is connected between the inverting input terminal of the voltage comparator and the output terminal of the voltage comparator.
Optionally, the temperature detection circuit further comprises a first diode and a second diode, the first diode is connected in parallel with the platinum thermal resistor, and the second diode is connected in parallel with the first resistor.
Optionally, the temperature detection circuit further comprises an RC circuit, and the RC circuit is connected between the voltage comparator and the single chip microcomputer.
Optionally, the RC circuit includes a sixth resistor and a first capacitor, where the sixth resistor is connected between the voltage comparator and the single-chip microcomputer, and the first capacitor is connected between the single-chip microcomputer and ground.
Optionally, the dual operational amplifier is model LM358.
Optionally, the temperature detection circuit further includes a filter capacitor connected between the positive power supply input pin and the negative power supply input pin of the dual operational amplifier.
Alternatively, the platinum resistor is PT1000 resistor.
The beneficial effects of the utility model are as follows: the utility model provides a temperature detection circuit, which widens the temperature detection range through a platinum thermal resistor, separates a first voltage division circuit from a voltage comparator through a voltage follower and prevents detection voltage from being influenced by a subsequent circuit. The reference voltage and the detection voltage are compared and amplified through a voltage comparator to obtain output voltage, and the output voltage is fed to a singlechip for detection, so that the corresponding relation between the temperature of the platinum thermal resistor and the output voltage can be established; when the temperature is detected, the singlechip calculates the temperature based on the corresponding relation by acquiring the output voltage. The utility model can expand the temperature detection range.
Drawings
In order to more clearly illustrate the embodiments of the present utility model or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic circuit diagram of a temperature detection circuit according to an embodiment of the present utility model;
fig. 2 is a schematic circuit diagram of another temperature detection circuit according to an embodiment of the present utility model.
Detailed Description
Reference will now be made in detail to the present embodiments of the present utility model, examples of which are illustrated in the accompanying drawings, wherein the accompanying drawings are used to supplement the description of the written description so that one can intuitively and intuitively understand each technical feature and overall technical scheme of the present utility model, but not to limit the scope of the present utility model.
In the description of the present utility model, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present utility model and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present utility model.
In the description of the present utility model, if there is a word description such as "a plurality" or the like, the meaning of a plurality means two or more ways, and greater than, less than, exceeding, etc. are understood to exclude the present number, and above, below, within, etc. are understood to include the present number.
In the description of the present utility model, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present utility model can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.
Referring to fig. 1, an embodiment of the present utility model provides a temperature detection circuit, including:
a dual operational amplifier 100, the dual operational amplifier 100 including a voltage follower IC1 and a voltage comparator IC2; the output end of the voltage follower IC1 is respectively connected with the inverting input end of the voltage follower IC1 and the inverting input end of the voltage comparator IC2;
the first voltage dividing circuit 200 comprises a platinum thermal resistor Rpt and a first resistor R1, wherein a first end of the platinum thermal resistor Rpt is connected with a power supply end VCC, a second end of the platinum thermal resistor Rpt is respectively connected with a non-phase input end of the voltage follower IC1 and one end of the first resistor R1, and the other end of the first resistor R1 is grounded;
a reference circuit 300, wherein the reference circuit 300 is connected with a non-inverting input terminal of the voltage comparator IC2;
the first voltage dividing circuit 200 is configured to input a detection voltage U1 to the voltage follower IC 1;
the voltage follower IC1 is configured to provide the detection voltage U1 to the voltage comparator IC2;
the reference circuit 300 is configured to provide a reference voltage U2 to the voltage comparator IC2;
the voltage comparator IC2 is configured to amplify a difference value between the first voltage input by the voltage follower IC1 and the reference voltage U2 to obtain an output voltage Uo, and send the output voltage Uo to the singlechip 400;
the singlechip 400 is configured to establish a correspondence between the output voltage Uo and the resistance of the platinum resistor Rpt, and perform temperature detection according to the correspondence.
The working principle of the utility model is as follows:
the detection voltage U1 is obtained by dividing the first resistor R1, but the resistance value of the platinum resistor Rpt does not change much, resulting in a small voltage change, and therefore it is necessary to amplify the detection voltage U1. The voltage output by the voltage follower IC1 is the detection voltage U1, and the voltage follower IC1 functions to isolate the first voltage dividing circuit 200 from the voltage comparator IC2, so as to prevent the detection voltage U1 from being affected by the following circuits. The reference voltage U2 and the detection voltage U1 are compared and amplified by the voltage comparator IC2 to obtain an output voltage Uo, and the output voltage Uo is supplied to the singlechip 400 for detection. Thus, the relation between the resistance of the platinum resistor Rpt and the output voltage Uo can be obtained, and the corresponding relation between the temperature of the platinum resistor Rpt and the output voltage Uo can be established by combining the relation between the temperature of the platinum resistor Rpt and the resistance; in the temperature detection, the single chip microcomputer 400 obtains the output voltage Uo and calculates the temperature based on the correspondence relationship.
In some embodiments, the reference circuit 300 includes a second resistor R2 and a third resistor R3; one end of the third resistor R3 is connected to the power supply end VCC, the other end of the third resistor R3 is connected to the non-inverting input end of the voltage comparator IC2 and one end of the second resistor R2, and the other end of the second resistor R2 is grounded.
In some embodiments, the reference circuit 300 further includes a variable resistor R7, where a regulating end of the variable resistor R7 is connected to a non-inverting input end of the voltage comparator IC2, and another two ends of the variable resistor R7 are respectively connected between the third resistor R3 and the second resistor R2.
In this embodiment, the variable resistor R7 may be used to adjust the reference voltage U2 for calibration.
In some embodiments, the temperature detection circuit further includes a second voltage division circuit 500, the second voltage division circuit 500 including a fourth resistor R4 and a fifth resistor R5; the fourth resistor R4 is connected between the output terminal of the voltage follower IC1 and the inverting input terminal of the voltage comparator IC2; the fifth resistor R5 is connected between the inverting input terminal of the voltage comparator IC2 and the output terminal of the voltage comparator IC 2.
By adopting the temperature detection circuit provided in this embodiment, the calculation formula of the output voltage Uo is:
Uo＝(1+R5/R4)×(R3/R2)×Vcc-((R5/R4)×R1/(R1+Rpt))×Vcc；
wherein Uo is the output voltage Uo, vcc is the voltage of the power supply terminal Vcc, rpt is the resistance of the platinum resistor Rpt, R1 is the resistance of the first resistor R1, R2 is the resistance of the second resistor R2, R3 is the resistance of the third resistor R3, R4 is the resistance of the fourth resistor R4, and R5 is the resistance of the fifth resistor R5.
In some embodiments, the temperature detection circuit further includes a first diode D1 and a second diode D2, the first diode D1 and the platinum thermal resistor Rpt are connected in parallel, and the second diode D2 and the first resistor R1 are connected in parallel.
In this embodiment, in order to prevent the LM358 from being damaged when the whole machine is breakdown-voltage, the first diode D1 and the second diode D2 are added to protect.
In some embodiments, the temperature detection circuit further includes an RC circuit 600, and the RC circuit 600 is connected between the voltage comparator IC2 and the single-chip microcomputer 400.
In some embodiments, the RC circuit 600 includes a sixth resistor R6 and a first capacitor C1, the sixth resistor R6 is connected between the voltage comparator IC2 and the single-chip microcomputer 400, and the first capacitor C1 is connected between the single-chip microcomputer 400 and the ground.
In this embodiment, the sixth resistor R6 and the first capacitor C1 perform protection and filtering functions.
Referring to fig. 2, in some embodiments, the dual op amp 100 is model LM358.
In some embodiments, the temperature detection circuit further comprises a filter capacitor C2, the filter capacitor C2 being connected between the positive power supply input pin v+ and the negative power supply input pin v+ of the dual operational amplifier 100.
In this embodiment, a dual op-amp integrated circuit chip of model LM358 may be used to implement the functions of voltage follower IC1 and voltage comparator IC 2. The power supply terminal VCC and ground of LM358 can be driven with wider voltages, for example, the voltage ranges between positive power input pin v+ and negative power input pin v+ can be (-5V-12V), so that the range of the output voltage Uo amplified by the voltage comparator IC2 is larger and will not be distorted.
In some embodiments, the platinum resistance Rpt employs a PT1000 resistance.
As the temperature range of the PT1000 thermal resistor is-200-500 ℃, the temperature detection circuit provided by the utility model can expand the temperature detection range.
While the present disclosure has been described in considerable detail and with particularity with respect to the several illustrated embodiments, it is not intended to be limited to any such detail or embodiments or any particular embodiment, but rather should be construed as providing broad interpretation of such claims by reference to the appended claims, taking into account the prior art to thereby effectively encompass the intended scope of the present disclosure. Furthermore, the foregoing description of the utility model has been presented in terms of embodiments foreseen by the inventor for the purpose of providing a enabling description for enabling the enabling description to be available, notwithstanding that insubstantial changes in the utility model, not presently foreseen, may nonetheless represent equivalents thereto.
Claims (10)
1. A temperature detection circuit, comprising:
a dual operational amplifier comprising a voltage follower and a voltage comparator; the output end of the voltage follower is respectively connected with the inverting input end of the voltage follower and the inverting input end of the voltage comparator;
the first voltage dividing circuit comprises a platinum thermal resistor and a first resistor, wherein the first end of the platinum thermal resistor is connected with a power supply end, the second end of the platinum thermal resistor is respectively connected with the positive input end of the voltage follower and one end of the first resistor, and the other end of the first resistor is grounded;
the reference circuit is connected with the non-inverting input end of the voltage comparator;
the first voltage dividing circuit is used for inputting detection voltage to the voltage follower;
the voltage follower is used for providing the detection voltage to the voltage comparator;
the reference circuit is used for providing reference voltage for the voltage comparator;
the voltage comparator is used for amplifying the difference value between the first voltage input by the voltage follower and the reference voltage to obtain an output voltage, and sending the output voltage to the singlechip;
and the singlechip is used for establishing a corresponding relation between the output voltage and the resistance value of the platinum resistor, and detecting the temperature according to the corresponding relation.
2. A temperature sensing circuit according to claim 1, wherein the reference circuit comprises a second resistor and a third resistor; one end of the third resistor is connected with a power supply end, the other end of the third resistor is respectively connected with the normal phase input end of the voltage comparator and one end of the second resistor, and the other end of the second resistor is grounded.
3. A temperature detection circuit according to claim 2, wherein the reference circuit further comprises a variable resistor, the regulating terminal of the variable resistor being connected to the non-inverting input terminal of the voltage comparator, the other two terminals of the variable resistor being connected between the third resistor and the second resistor, respectively.
4. The temperature detection circuit of claim 1, further comprising a second voltage divider circuit, the second voltage divider circuit comprising a fourth resistor and a fifth resistor; the fourth resistor is connected between the output end of the voltage follower and the inverting input end of the voltage comparator; the fifth resistor is connected between the inverting input terminal of the voltage comparator and the output terminal of the voltage comparator.
5. The temperature sensing circuit of claim 1, further comprising a first diode and a second diode, wherein the first diode is connected in parallel with the platinum thermal resistor, and wherein the second diode is connected in parallel with the first resistor.
6. The temperature detection circuit of claim 1, further comprising an RC circuit connected between the voltage comparator and the single-chip microcomputer.
7. The temperature sensing circuit of claim 6, wherein the RC circuit comprises a sixth resistor and a first capacitor, the sixth resistor is connected between the voltage comparator and the single-chip microcomputer, and the first capacitor is connected between the single-chip microcomputer and ground.
8. A temperature sensing circuit according to claim 1, wherein the dual op-amp is model LM358.
9. The temperature sensing circuit of claim 8, further comprising a filter capacitor connected between the positive and negative power supply input pins of the dual op-amp.
10. A temperature sensing circuit according to claim 1, wherein the platinum resistance is PT1000 resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322031988.5U CN220418680U (en) | 2023-07-31 | 2023-07-31 | Temperature detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322031988.5U CN220418680U (en) | 2023-07-31 | 2023-07-31 | Temperature detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220418680U true CN220418680U (en) | 2024-01-30 |
Family
ID=89646037
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322031988.5U Active CN220418680U (en) | 2023-07-31 | 2023-07-31 | Temperature detection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220418680U (en) |
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2023
- 2023-07-31 CN CN202322031988.5U patent/CN220418680U/en active Active
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