CN215262148U - Thermistor temperature measuring circuit - Google Patents
Thermistor temperature measuring circuit Download PDFInfo
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- CN215262148U CN215262148U CN202121439045.0U CN202121439045U CN215262148U CN 215262148 U CN215262148 U CN 215262148U CN 202121439045 U CN202121439045 U CN 202121439045U CN 215262148 U CN215262148 U CN 215262148U
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Abstract
The utility model discloses a thermistor temperature measuring circuit, which comprises a temperature detecting circuit, a detection voltage differential amplifying circuit and a detection voltage reversal amplifying circuit which are connected in sequence; the temperature detection circuit is used for outputting voltage which changes correspondingly when the resistance value of the thermistor changes along with the temperature; the detection voltage differential amplifying circuit is used for adjusting the output voltage of the temperature detection circuit into negative voltage output proportional to the temperature; the detection voltage reversal amplifying circuit is used for converting the output voltage of the detection voltage differential amplifying circuit into amplified positive voltage output. The utility model discloses a temperature measurement circuit can export the voltage along with temperature proportional change when the circuit has realized sampling temperature change, and output voltage can be linear variation within a certain range in whole temperature variation within range, and the interference killing feature is strong, has solved the not high problem of prior art precision, and this circuit easily adjusts and matches back level circuit, low cost, and application prospect is wide.
Description
Technical Field
The utility model relates to a circuit, specific theory relates to a thermistor temperature measurement circuit.
Background
At present, a simple series thermistor voltage division circuit or a special temperature measurement chip is usually used for realizing a temperature measurement circuit. However, both of the two methods have certain technical problems, for example, although the series thermistor voltage division circuit is simple and easy to implement, the precision is not high, and the matching performance with a post-stage circuit is poor; the use of a dedicated temperature measurement chip is often costly and not conducive to the realization of localization. Therefore, it is necessary to develop a temperature measuring circuit with high measurement accuracy.
Disclosure of Invention
An object of the utility model is to provide an adjustable thermistor temperature measurement circuit to current temperature measurement circuit's not enough.
In order to achieve the above purpose, the utility model discloses the technical scheme who takes includes:
a thermistor temperature measuring circuit comprises a temperature detection circuit, a detection voltage differential amplification circuit and a detection voltage reversal amplification circuit which are connected in sequence;
the temperature detection circuit is used for outputting voltage which changes correspondingly when the resistance value of the thermistor changes along with the temperature;
the detection voltage differential amplifying circuit is used for adjusting the output voltage of the temperature detection circuit into negative voltage output proportional to the temperature;
the detection voltage reversal amplifying circuit is used for converting the output voltage of the detection voltage differential amplifying circuit into amplified positive voltage for output.
Further, the temperature detection circuit comprises a voltage division resistor circuit and an operational amplifier OP1, wherein the voltage division resistor circuit comprises a compensation resistor R3 and a thermistor R which are connected in seriesTHThe common terminal of the two is connected with the non-inverting input terminal of an operational amplifier OP1, and a thermistor RTHThe other end of the resistor is grounded, the other end of the R3 resistor is connected with the current-limiting resistor R1, the other end of the R1 resistor is connected with the +15V end, the common end of the resistor R1 and the resistor R3 is connected with the resistor R2, and the other end of the resistor R2 is grounded.
Further, the temperature detection circuit further comprises capacitors C1, C2 and a capacitor C3, wherein one end of the capacitor C1 is connected with a common end connected with resistors R1, R2 and R3, the other end of the capacitor C1 is grounded, a 4-pin of a power supply end of the operational amplifier OP1 is connected with a +15V end, the common end of the connection of the two is connected with one end of a capacitor C2, the other end of the capacitor C2 is grounded, a 5-pin of the operational amplifier OP1 is connected with a-15V end, the common end of the connection of the two is connected with one end of the capacitor C3, the other end of the capacitor C3 is grounded, a 2-pin reverse input end of the operational amplifier 1 is connected with a pin 1 of an output end, and the common end of the connection of the two is connected with the detection voltage differential amplification circuit 2.
Further, the detection voltage differential amplifying circuit comprises an operational amplifier OP2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9 and a variable resistor VR1, wherein the resistor R4 is connected with the resistor R5, a common end of the connection of the resistors R7 and R5 is connected with a pin 5 at the non-inverting input end of the operational amplifier OP2, the other end of the resistor R4 is connected with the output end of the operational follower OP1, and the other end of the resistor R5 is connected to the ground; the resistor R6 is connected with the resistor R7, the common end of the connection of the resistor R6 and the resistor R7 is connected with the pin 6 of the inverting input end of the operational amplifier OP2, the other end of the resistor R6 is connected with the pin 7 of the output end of the operational amplifier OP2, the common end of the connection of the resistor R6 and the resistor R7 is connected with the detection voltage inverting amplifying circuit 3, the other end of the connection of the resistor R7 is connected with the variable resistor VR1, the common end of the connection of the resistor R9 and the resistor R9 is grounded, the other end of the variable resistor VR1 is connected with the resistor R8, and the other end of the resistor R8 is connected with the +5V end.
Further, the detection voltage inverting and amplifying circuit comprises an operational amplifier OP3, a resistor R10, a resistor R10 and a variable resistor VR2, wherein the non-inverting input end of the operational amplifier OP3 is grounded, the resistor R10 is connected with the resistor R11, the common end of the connection of the non-inverting input end and the resistor R11 is connected with the inverting input end of the operational amplifier OP3, the other end of the resistor R11 is connected with a variable resistor VR2, the other end of the variable resistor VR2 is connected with the output end of the operational amplifier OP3, and the common end of the connection of the common end and the voltage end is connected with 0-5V.
Compared with the prior art, the beneficial effects of the utility model are as follows:
the utility model provides a thermistor temperature measuring circuit, temperature measuring circuit can export the voltage along with temperature proportional change when having realized the sampling temperature change, the value through adjusting among the differential amplifier circuit variable resistance VR1 realizes that the temperature is 0V for 0 ℃ circuit output voltage, circuit output voltage is +5V when the value of adjustment detection voltage reversal amplifier circuit variable resistance VR2 realizes that the temperature rises to the setting value, output voltage can be linear change in 0V- +5V scope in whole temperature variation within range, the interference killing feature is strong, the problem that the prior art precision is not high has been solved, and this circuit easily adjusts and matches the back level circuit, can be connected with the voltmeter and measure the temperature, also can connect AD converter transformation for the digital quantity, utilize tools such as computer to measure, therefore, the carrier wave prepaid electric energy meter is low in cost, application prospect is wide.
Drawings
Fig. 1 is a schematic circuit diagram of the present invention;
the reference numerals in the figures denote:
1. a temperature detection circuit; 2. a detection voltage differential amplifying circuit; 3. and a detection voltage inversion amplification circuit.
Detailed Description
The invention will be described in further detail with reference to the accompanying drawings:
with reference to fig. 1, the present invention discloses a thermistor temperature measuring circuit, which comprises a temperature detecting circuit 1, a detecting voltage differential amplifying circuit 2 and a detecting voltage reversal amplifying circuit 3, which are connected in sequence;
the temperature detection circuit 1 is used for outputting voltage which changes correspondingly when the resistance value of the thermistor changes along with the temperature, and the resistance value of the thermistor is reduced and the output voltage is reduced along with the rise of the temperature; the detection voltage differential amplifier circuit 2 is used for adjusting the output voltage of the temperature detection circuit 1 to a negative voltage output proportional to the temperature; the detection voltage inverting and amplifying circuit 3 is used for converting the output voltage of the detection voltage differential amplifying circuit 2 into a positive voltage output which is inverted and amplified by a multiple of- (R11+ VR 2)/R10.
Specifically, the temperature detection circuit 1 includes a voltage dividing resistance circuit including a compensation circuit connected in series and a voltage followerResistor R3 and thermistor RTHThe common terminal of the two is connected with the non-inverting input terminal of an operational amplifier OP1 (as a voltage follower), and a thermistor RTHThe other end of the resistor is grounded, the other end of the R3 resistor is connected with the current-limiting resistor R1, the other end of the R1 resistor is connected with the +15V end, the common end of the resistor R1 and the resistor R3 is connected with the resistor R2, and the other end of the resistor R2 is grounded.
The temperature detection circuit 1 further comprises capacitors C1, C2 and a capacitor C3, one end of the capacitor C1 is connected with a common end connected with the resistors R1, R2 and R3, the other end of the capacitor C1 is grounded, a power supply end 4 pin of an operational amplifier OP1 is connected with a +15V end, the common end connected with the capacitors is connected with one end of a capacitor C2, the other end of the capacitor C2 is grounded, a pin 5 of the operational amplifier OP1 is connected with a-15V end, the common end connected with the capacitors is connected with one end of the capacitor C3, the other end of the capacitor C3 is grounded, a pin 2 inverting input end of the operational amplifier OP1 is connected with a pin 1 of the output end, and the common end connected with the detection voltage differential amplification circuit 2.
In the scheme, the compensation resistor R3 has the function of linearizing corresponding voltage division change when the thermistor changes along with temperature, and the current limiting resistors R1 and R2 are the thermistor RTHThe capacitors C1, C2 and C3 are used for filtering noise in the power circuit.
Specifically, the detection voltage differential amplification circuit 2 comprises an operational amplifier OP2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9 and a variable resistor VR1, wherein the resistor R4 is connected with the resistor R5, a common end of the connection of the resistors R4 and R5 is connected with a pin 5 at the non-inverting input end of the operational amplifier OP2, the other end of the resistor R4 is connected with the output end of the operational follower OP1, and the other end of the resistor R5 is connected with the ground; the resistor R6 is connected with the resistor R7, the common end of the connection of the resistor R6 and the resistor R7 is connected with the pin 6 of the inverting input end of the operational amplifier OP2, the other end of the resistor R6 is connected with the pin 7 of the output end of the operational amplifier OP2, the common end of the connection of the resistor R6 and the resistor R7 is connected with the detection voltage inverting amplifying circuit 3, the other end of the connection of the resistor R7 is connected with the variable resistor VR1, the common end of the connection of the resistor R9 and the resistor R9 is grounded, the other end of the variable resistor VR1 is connected with the resistor R8, and the other end of the resistor R8 is connected with the +5V end.
In the scheme, the resistors R4-R7 and the operational amplifier OP2 form a differential amplifier to work together, and the resistors R8, R9 and the variable resistor VR1 are used for providing voltage to enable the output voltage of the OP2 to be 0V when the temperature is 0 ℃.
Specifically, the detection voltage inverting and amplifying circuit 3 comprises an operational amplifier OP3 (serving as an inverting amplifier), a resistor R10, a resistor R10 and a variable resistor VR2, wherein the non-inverting input end of the operational amplifier OP3 is grounded, the resistor R10 is connected with the resistor R11, the common end of the connection of the resistors is connected with the inverting input end of the operational amplifier OP3, the other end of the resistor R11 is connected with the variable resistor VR2, the other end of the variable resistor VR2 is connected with the output end of the operational amplifier OP3, and the common end of the connection of the resistors is connected with the voltage end of 0-5V.
In the above configuration, the resistors R10 and R11, the variable resistor VR2, and the operational amplifier OP3 together form an inverting amplifier circuit, and the output voltage of the detected voltage differential amplifier circuit 2 is set to- (R) as — (R) value11+VR2)/R10And (4) outputting the amplified positive voltage by multiple inversion.
The utility model discloses a theory of operation does: when the resistance value of the thermistor RTH changes with temperature, the voltage at the non-inverting input terminal of the operational amplifier OP1 connected thereto changes, so that the voltage at the output terminal of the operational amplifier OP1 serving as a voltage follower changes. The output signal of the operational amplifier OP1 is applied to the non-inverting input terminal of the differential amplifier composed of the operational amplifier OP2 and the resistors R4-R7, and the voltage divided by +5V is applied to the inverting input terminal by the resistors R8, R9 and VR1, and the output voltage of the OP2 can be adjusted to 0V by adjusting the variable resistor VR1 so as to output a negative voltage proportional to the temperature rise when the temperature is 0 ℃. The output voltage of the operational amplifier OP2 is applied to an inverting amplifier circuit constituted by OP3 and amplified and outputted in- (R11+ VR2)/R10, and by adjusting the resistances of VR1 and VR2, the output voltage is 0V at the measurement temperature of 0 ℃ and +5V at the measurement temperature of the set value. The utility model discloses a temperature measurement circuit easily adjusts and matches back level circuit, low cost, safety and stability, and application prospect is wide.
The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can change or replace the present invention without creative efforts within the technical scope of the present invention.
Claims (5)
1. A thermistor temperature measuring circuit is characterized by comprising a temperature detection circuit (1), a detection voltage differential amplification circuit (2) and a detection voltage reversal amplification circuit (3) which are sequentially connected;
the temperature detection circuit (1) is used for outputting voltage which changes correspondingly when the resistance value of the thermistor changes along with the temperature;
the detection voltage differential amplifying circuit (2) is used for adjusting the output voltage of the temperature detection circuit (1) to be negative voltage output proportional to the temperature;
the detection voltage reversal amplifying circuit (3) is used for converting the output voltage of the detection voltage differential amplifying circuit (2) into amplified positive voltage and outputting the amplified positive voltage.
2. The thermistor temperature measuring circuit according to claim 1, characterized in that the temperature detection circuit (1) comprises a voltage divider resistance circuit comprising a compensation resistor R3 and a thermistor R connected in series and an operational amplifier OP1THThe common terminal of the two is connected with the non-inverting input terminal of an operational amplifier OP1, and a thermistor RTHThe other end of the resistor is grounded, the other end of the R3 resistor is connected with the current-limiting resistor R1, the other end of the R1 resistor is connected with the +15V end, the common end of the resistor R1 and the resistor R3 is connected with the resistor R2, and the other end of the resistor R2 is grounded.
3. The thermistor temperature measuring circuit according to claim 2, characterized in that the temperature detecting circuit (1) further comprises capacitors C1, C2 and C3, wherein one end of the capacitor C1 is connected to the common terminal of the resistors R1, R2 and R3, the other end of the capacitor C1 is grounded, the 4-pin of the power supply terminal of the operational amplifier OP1 is connected to the +15V terminal, the common terminal of the connection is connected to one end of the capacitor C2, the other end of the capacitor C2 is grounded, the 5-pin of the operational amplifier OP1 is connected to the-15V terminal, the common terminal of the connection is connected to one end of the capacitor C3, the other end of the capacitor C3 is grounded, the 2-pin reverse input terminal of the operational amplifier OP1 is connected to the output terminal 1 pin, and the common terminal of the connection is connected to the detecting voltage differential amplifying circuit (2).
4. The thermistor temperature measuring circuit according to claim 1, characterized in that the detection voltage differential amplifying circuit (2) comprises an operational amplifier OP2, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a resistor R9, and a variable resistor VR1, wherein the resistor R4 is connected with the resistor R5, the common terminal of the connection is connected with the non-inverting input terminal 5 pin of the operational amplifier OP2, the other terminal of the resistor R4 is connected with the output terminal of the operational follower OP1, and the other terminal of the resistor R5 is connected with the ground; the resistor R6 is connected with the resistor R7, the common end of the connection of the resistor R6 and the resistor R6 is connected with the pin 6 of the inverting input end of the operational amplifier OP2, the other end of the resistor R6 is connected with the pin 7 of the output end of the operational amplifier OP2, the common end of the connection of the resistor R6 and the resistor R7 is connected with the detection voltage inversion amplifying circuit (3), the other end of the connection of the resistor R7 is connected with the variable resistor VR1, the common end of the connection of the resistor R9 is connected with one end of the resistor R9, the other end of the resistor R9 is grounded, the other end of the variable resistor VR1 is connected with the resistor R8, and the other end of the resistor R8 is connected with the +5V end.
5. The thermistor temperature measuring circuit according to claim 1, characterized in that the sense voltage inverting amplifier circuit (3) comprises an operational amplifier OP3, a resistor R10, a resistor R10 and a variable resistor VR2, wherein the non-inverting input terminal of the operational amplifier OP3 is grounded, the resistor R10 is connected to R11, the common terminal of the connection is connected to the inverting input terminal of the operational amplifier OP3, the other terminal of the resistor R11 is connected to a variable resistor VR2, the other terminal of the variable resistor VR2 is connected to the output terminal of the operational amplifier OP3, and the common terminal of the connection is connected to the voltage terminal 0-5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121439045.0U CN215262148U (en) | 2021-06-25 | 2021-06-25 | Thermistor temperature measuring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202121439045.0U CN215262148U (en) | 2021-06-25 | 2021-06-25 | Thermistor temperature measuring circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN215262148U true CN215262148U (en) | 2021-12-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202121439045.0U Active CN215262148U (en) | 2021-06-25 | 2021-06-25 | Thermistor temperature measuring circuit |
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| Country | Link |
|---|---|
| CN (1) | CN215262148U (en) |
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2021
- 2021-06-25 CN CN202121439045.0U patent/CN215262148U/en active Active
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