CN208780365U - A kind of detection circuit of PT100 temperature sensor - Google Patents
A kind of detection circuit of PT100 temperature sensor Download PDFInfo
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Abstract
The utility model discloses a kind of detection circuits of PT100 temperature sensor, including input terminal, constant current source unit, the first filter unit, the first amplifier unit and control unit；Wherein, the input terminal is the input terminal of PT100 temperature sensor, and the output end of the constant current source unit is connected to the input terminal, for providing a constant input current for the PT100 temperature sensor；The input terminal of first filter unit is connected to the input terminal, for filtering out the ripple in the PT100 temperature sensor rectifier output voltage to obtain d. c. voltage signal；The positive input of the first amplifier unit is connected to the output end of first filter unit, for amplifying the d. c. voltage signal to obtain high input impedance；The input terminal of described control unit is connected to the output end of the first amplifier unit, for detecting the temperature of the PT100 temperature sensor according to the d. c. voltage signal.
Description
Technical Field
The utility model relates to a temperature measurement technical field, more specifically relate to a PT100 temperature sensor's detection circuitry.
Background
The PT100 temperature sensor is a temperature sensor with the resistance value changing along with the temperature change, has the characteristics of high measurement accuracy, reliable and stable performance, high mechanical strength, long product service life and the like, and is widely applied to the fields of meteorology, agriculture and forestry, chemical fiber, food, automobiles, household appliances, industrial automatic measurement, various experimental instruments and meters and the like. At present, the detection method for the PT100 temperature sensor includes a resistance voltage division detection circuit, a constant current source detection circuit, a relatively complex bridged differential detection circuit, and the like, and these detection circuits have advantages and disadvantages, wherein the constant current source detection method is more widely applied and more reliable, but also has the disadvantages of smaller acquired signal impedance, poorer detection accuracy, complex circuit design, and the like.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that a PT100 temperature sensor's detection circuitry is provided, detection circuitry can realize PT100 temperature sensor's accurate detection, PT100 temperature sensor's detection circuitry aims at solving the impedance that exists in the present constant current source detection method less, and it is relatively poor to detect the precision, and circuit design is complicated scheduling problem.
In order to solve the technical problem, the utility model provides a detection circuit of PT100 temperature sensor, the detection circuit includes input, constant current source unit, first filter unit, first fortune is put unit and the control unit; the input end is the input end of a PT100 temperature sensor, and the output end of the constant current source unit is connected to the input end and used for providing a constant input current for the PT100 temperature sensor; the input end of the first filtering unit is connected to the input end and used for filtering out ripples in the rectified output voltage of the PT100 temperature sensor to obtain a direct-current voltage signal; the positive input end of the first operational amplifier unit is connected to the output end of the first filtering unit and used for amplifying the direct-current voltage signal to obtain high input impedance; and the input end of the control unit is connected to the output end of the first operational amplifier unit and is used for detecting the temperature of the PT100 temperature sensor according to the direct-current voltage signal.
In the detection circuit of the PT100 temperature sensor provided by the present invention, the constant current source unit includes a first integrated unit and a sampling unit, an input terminal of the first integrated unit is connected to a first power source terminal, an output terminal thereof is connected to an input terminal of the sampling unit, a voltage regulating terminal thereof is connected to an input terminal of the first filtering unit, the first integrated unit is used for providing a constant input voltage for the sampling unit; the output end of the sampling unit is used as the output end of the constant current source unit and is connected to the input end.
The utility model provides an among PT100 temperature sensor's the detection circuitry, first integrated circuit chip for having constant voltage output, the sampling unit includes at least one resistance, at least one resistance establish ties in proper order after connect in first integrated unit's output with between PT100 temperature sensor's the input.
The utility model provides an among PT100 temperature sensor's the detection circuitry, detection circuitry still includes first clamper protection unit, first clamper protection unit includes first diode and second diode, first diode cathode is connected to first power end, its positive pole is connected to the negative pole of second diode, the positive pole of second diode is connected to PT100 temperature sensor's input.
The utility model provides an among PT100 temperature sensor's detection circuitry, first filtering unit includes third resistance and first electric capacity, the one end of third resistance is connected to the input, its other end is connected to first electric capacity with between the forward input of first fortune unit, the other end ground connection of first electric capacity.
In the detection circuit of the PT100 temperature sensor provided by the present invention, the first operational amplifier unit includes a fourth resistor, a fifth resistor and an in-phase proportional operational amplifier, a positive input terminal of the in-phase proportional operational amplifier is connected to the third resistor and the first capacitor as an input terminal of the first operational amplifier unit, a negative input terminal thereof is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected to the ground between the first capacitor and the ground; one end of the fifth resistor is connected to the negative input end, the other end of the fifth resistor is connected to the output end of the in-phase proportional operational amplifier, and the output end of the in-phase proportional operational amplifier is used as the output end of the first operational amplifier unit.
The utility model provides an among PT100 temperature sensor's the detection circuitry, detection circuitry still includes second clamper protection unit, second clamper protection unit includes third diode and fourth diode, the negative pole of third diode is connected to the positive pole of fourth diode with between the positive input of cophase proportion operational amplifier, its positive pole ground connection, the negative pole of fourth diode is connected to the second power end.
The utility model provides an among PT100 temperature sensor's the detection circuitry, detection circuitry still includes second filter unit, second filter unit includes sixth resistance and second electric capacity, the one end of sixth resistance is connected to the output of unit is put to first fortune, and its other end is connected to the second electric capacity with between the input of the control unit, the other end ground connection of second electric capacity.
The utility model provides an among PT100 temperature sensor's the detection circuitry, detection circuitry still includes third clamper protection unit, third clamper protection unit includes that unit and reference voltage generation unit are put to clamp subunit, second fortune, the positive direction input of unit is put to the second fortune is connected to the output of reference voltage generation unit, its negative-going input is connected to the clamp subunit with between the second filtering unit, its output is connected to the one end of clamp subunit, the other end ground connection of clamp subunit.
In the detection circuit of the PT100 temperature sensor provided by the present invention, the reference voltage generating unit includes a second integrated unit, a first transistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a third capacitor and a fourth capacitor, wherein an input terminal of the second integrated unit is connected between a control terminal of the first transistor and the seventh resistor, an output terminal of the second integrated unit is connected between the ninth resistor and the tenth resistor, a voltage adjustment terminal of the second integrated unit is grounded, the other terminal of the seventh resistor is connected to one terminal of the eighth resistor and to a third power terminal, the other terminal of the eighth resistor is connected to the input terminal of the first transistor, an output terminal of the first transistor is connected between the ninth resistor and the fourth capacitor as an output terminal of the reference voltage generating unit, and the other terminal of the fourth capacitor is grounded, one end of the third capacitor is connected to the third power supply end, and the other end of the third capacitor is grounded.
The embodiment of the utility model provides a PT100 temperature sensor's detection circuitry. Implement the embodiment of the utility model provides a can realize PT100 temperature sensor's accurate detection, the utility model discloses the constant current source detection method that adopts is simple more reliable, and the feasibility is higher, can obtain higher input impedance through the design together compare example operational amplifier circuit, and is more accurate, true to acquireing of small-signal, and its measurement accuracy is higher.
The invention will become more apparent from the following description when taken in conjunction with the accompanying drawings which illustrate embodiments of the invention.
Drawings
Fig. 1 is a block diagram of a detection circuit of a PT100 temperature sensor according to a first embodiment of the present invention;
fig. 2 is a block diagram of a detection circuit of a PT100 temperature sensor according to a second embodiment of the present invention;
fig. 3 is a block schematic diagram of a detection circuit of a PT100 temperature sensor according to a second embodiment of the present invention; and
fig. 4 is a specific circuit diagram of a detection circuit of a PT100 temperature sensor according to a second embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, wherein like component numbers represent like components. It is obvious that the embodiments to be described below are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
The utility model provides a PT100 temperature sensor's detection circuitry. The detection circuit comprises an input end, a constant current source unit, a first filtering unit, a first operational amplifier unit and a control unit; the input end is the input end of a PT100 temperature sensor, and the output end of the constant current source unit is connected to the input end and used for providing a constant input current for the PT100 temperature sensor; the input end of the first filtering unit is connected to the input end and used for filtering out ripples in the rectified output voltage of the PT100 temperature sensor to obtain a direct-current voltage signal; the positive input end of the first operational amplifier unit is connected to the output end of the first filtering unit and used for amplifying the direct-current voltage signal to obtain high input impedance; and the input end of the control unit is connected to the output end of the first operational amplifier unit and is used for detecting the temperature of the PT100 temperature sensor according to the direct-current voltage signal. Specifically, this PT100 temperature sensor's detection circuitry has designed a simple reliable constant current source unit, will the produced constant current source unit constant current source output arrives PT100 temperature sensor's forward input end is in order to obtain a constant voltage signal to with this constant voltage signal output first filter cell and first fortune put the unit and carry out filtering and amplification processing, finally with this constant voltage signal input to the control unit, in order to realize the detection of PT100 temperature sensor's temperature can effectively accurate detection PT100 temperature sensor has solved the acquisition signal impedance that constant current source detection method exists among the prior art and has hanged down, the precision is lower and circuit design complicacy scheduling problem, moreover the embodiment of the utility model provides a circuit is simple, realizes with low costs, has higher ease for use and practicality.
Fig. 1 is a block diagram of a detection circuit of a PT100 temperature sensor according to a first embodiment of the present invention. As shown in the figure, the detection circuit 100 includes an input terminal 15, a constant current source unit 11, a first filtering unit 12, a first operational amplifier unit 13 and a control unit 14, wherein the input terminal 15 is an input terminal of a PT100 temperature sensor, and an output terminal of the constant current source unit 11 is connected to the input terminal 15 for providing a constant input current for the PT100 temperature sensor; the input end of the first filtering unit 12 is connected to the input end 15, and is configured to filter out ripples in the rectified output voltage of the PT100 temperature sensor to obtain a direct-current voltage signal, so as to prevent an external environment from generating electromagnetic interference on the voltage signal output by the PT100 temperature sensor, thereby causing the signal to be unstable; a positive input end of the first operational amplifier unit 13 is connected to an output end of the first filtering unit 12, and is configured to amplify the dc voltage signal to obtain a high input impedance; an input end of the control unit 14 is connected to an output end of the first operational amplifier unit 13, and is configured to detect a temperature of the PT100 temperature sensor according to the dc voltage signal.
Referring to fig. 2 to 4, fig. 2 is a block diagram of a detection circuit of a PT100 temperature sensor according to a second embodiment of the present invention; fig. 3 is a block schematic diagram of a detection circuit of a PT100 temperature sensor according to a second embodiment of the present invention; fig. 4 is a specific circuit diagram of a detection circuit of a PT100 temperature sensor according to a second embodiment of the present invention. As shown in fig. 2, the detection circuit of the PT100 temperature sensor further includes a first clamping protection unit 15, a second clamping protection unit 17, a third clamping protection unit 18, and a second filtering unit 19, and in this embodiment, the designed multiple clamping circuits make the detection circuit of the PT100 temperature sensor more reliable and safer.
In one embodiment, as shown in fig. 3 to 4, the constant current source unit 11 includes a first integration unit 111 and a sampling unit 112, an input terminal of the first integration unit 111 is connected to a first power terminal VCC1, an output terminal thereof is connected to an input terminal of the sampling unit 112, a voltage regulation terminal thereof is connected to an input terminal of the first filtering unit 12, and the first integration unit 111 is configured to provide a constant input voltage for the sampling unit 12; an output terminal of the sampling unit 12 is connected to the input terminal 15 as an output terminal of the constant current source unit 11. In one embodiment, the first integrated unit 111 is an integrated circuit chip with a constant voltage output, which includes, for example, a LM317 chip, a LM217 chip, an AZ431 chip, and a TL431 chip. By utilizing the characteristic that the first integration unit 111 has a constant output voltage, a constant input voltage can be provided for the sampling unit 112. In an embodiment, for example, in the present embodiment, an LM317 chip, for example, may be adopted as the first integrated unit 111, and the LM317 chip includes three pins, i.e., an input pin, an output pin, and a voltage regulation pin. Wherein the input pin is connected to the first power supply terminal, the output pin is connected to the sampling unit 112, the voltage regulation pin is connected to the input terminal of the first filter unit 12, the input pin and the output pin are grounded, that is, the input pin is connected between the first power supply terminal VCC1 and a sixth capacitor C6, the other end of the sixth capacitor C6 is grounded, the output pin is connected between the sampling unit 112 and a fifth capacitor C5, and the other end of the fifth capacitor C5 is grounded. The sampling unit 112 includes at least one resistor, and the at least one resistor is sequentially connected in series and then connected between the output terminal of the first integrated unit 111 and the input terminal of the PT100 temperature sensor. In an embodiment, as shown in fig. 4, the sampling unit 112 includes a first resistor R1 and a second resistor R2, the first resistor R1 and the second resistor R2 are sequentially connected in series and then connected between the output terminal of the first integrated unit 111 and the input terminal of the PT100 temperature sensor, and a constant current value required by the detection circuit of the PT100 temperature sensor can be quickly and conveniently debugged through the matching of the resistances of the first resistor R1 and the second resistor R2.
In an embodiment, the first filtering unit 12 includes a third resistor R3 and a first capacitor C1, one end of the third resistor R3 is connected to the input terminal 15, the other end of the third resistor R3526 is connected between the first capacitor C1 and the positive input terminal of the first operational amplifier unit 13, and the other end of the first capacitor C1 is grounded; the first filtering unit 12 is configured to filter ripples in the rectified output voltage of the PT100 temperature sensor to obtain a dc voltage signal, reduce a ripple coefficient of the output voltage, make a waveform smoother, and prevent an external environment from generating electromagnetic interference on a voltage signal output by the PT100 temperature sensor, thereby causing the signal to be unstable; or preventing the client from mistakenly connecting the positive electrode and the negative electrode of the PT100 temperature sensor and burning out the PT100 temperature sensor.
In an embodiment, the first operational amplifier unit 13 includes a fourth resistor R4, a fifth resistor R5, and a non-inverting proportional operational amplifier U4, a positive input terminal of the non-inverting proportional operational amplifier U4 serving as the input terminal of the first operational amplifier unit 13 is connected between the third resistor R3 and the first capacitor C1, a negative input terminal thereof is connected to one end of a fourth resistor R4, and the other end of the fourth resistor R4 is connected between the first capacitor C1 and a ground terminal GND; one end of the fifth resistor R5 is connected to the negative input end, and the other end thereof is connected to the output end of the in-phase proportional operational amplifier U4, and the U4 output end of the in-phase proportional operational amplifier serves as the output end of the first operational amplifier unit 13. The in-phase proportional operational amplifier U4 can obtain higher input impedance, so that small signals can be obtained more accurately and truly, and the temperature measurement precision is greatly improved.
In one embodiment, as shown in fig. 3 to 4, the detection circuit 100 further includes a first clamp protection unit 16, the first clamp protection unit 16 includes a first diode D1 and a second diode D2, a cathode of the first diode D1 is connected to the first power source terminal VCC1, an anode of the first diode D1 is connected to a cathode of the second diode D2, and an anode of the second diode D2 is connected to the input terminal 15 of the PT100 temperature sensor. The first diode D1 and the second diode D2 constitute an overvoltage clamping circuit at the input terminal 15 of the PT100 temperature sensor, the first clamping protection circuit 16 is configured to clamp the input voltage of the PT100 temperature sensor at a first power terminal VCC1 when the PT100 temperature sensor inputs a high voltage, that is, the input voltage of the PT100 temperature sensor is less than or equal to a voltage value of the first power terminal VCC1, and the first clamping protection circuit 16 is configured to protect the PT100 temperature sensor.
In an embodiment, as shown in fig. 3 to 4, the detection circuit 100 further includes a second clamping protection unit 17, the second clamping protection unit 17 includes a third diode D3 and a fourth diode D4, a cathode of the third diode D3 is connected between an anode of the fourth diode D4 and the positive input terminal of the in-phase proportional operational amplifier U4, an anode thereof is grounded, and a cathode of the fourth diode D4 is connected to a second power source terminal VCC 2. The second clamping protection circuit 17 is configured to clamp the high voltage at a second power supply terminal VCC2 if the voltage flowing through the first filtering unit 12 is the high voltage; if the voltage flowing through the first filter unit 12 is a low voltage, the low voltage is clamped to the conducting voltage of the third diode D3, that is, the forward voltage input to the first operational amplifier unit 13 is less than or equal to the voltage value of the second power terminal VCC2, the negative voltage input to the first operational amplifier unit 13 is less than or equal to the voltage value of the conducting voltage of the third diode D3, and the second clamp protection circuit 17 is used for protecting the first operational amplifier unit 13 and preventing the voltage input to the first operational amplifier unit 13 from being too high or too low to cause burning.
In an embodiment, the detection circuit 100 further includes a third clamping protection unit 18, the third clamping protection unit 18 includes a reference voltage generation unit 181, a second operational amplifier unit 182, and a clamping subunit 183, a positive input end of the second operational amplifier unit 13 is connected to an output end of the reference voltage generation unit 181, a negative input end thereof is connected between the clamping subunit 183 and the second filtering unit 12, an output end thereof is connected to one end of the clamping subunit 183, and the other end of the clamping subunit 183 is grounded. In one embodiment, for example, in this embodiment, the reference voltage generating unit 181 includes a second integrated unit U2, a first transistor Q1, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a third capacitor C3, and a fourth capacitor C4, wherein an input terminal of the second integrated unit U2 is connected between a control terminal of the first transistor Q1 and the seventh resistor R7, an output terminal of the second integrated unit U2 is connected between the ninth resistor R9 and the tenth resistor R10, a voltage regulating terminal of the second integrated unit U2 is grounded GND, another terminal of the seventh resistor R7 and one terminal of the eighth resistor R8 are connected to a third power terminal VCC3, another terminal of the eighth resistor R8 is connected to an input terminal of the first transistor Q1, an output terminal of the first transistor Q1 is connected between the ninth resistor R9 and the fourth capacitor C4 to serve as the output terminal of the reference voltage generating unit 181, the other end of the fourth capacitor C4 is grounded, one end of the third capacitor C3 is connected to the third power source terminal VCC3, and the other end is grounded. Wherein the third power terminal VCC3, the seventh resistor R7 and the eighth resistor R8 cooperate with each other to make the first transistor Q1 operate in a conducting state, so that the reference voltage generating unit 181 generates a constant voltage V _ ref, wherein when the current of the second operational amplifier unit 182 increases, the constant voltage V _ ref tends to decrease, and the first transistor Q1 automatically adjusts the voltage difference to compensate for the constant voltage V _ ref to keep a stable output; when the current of the second operational amplifier unit 182 decreases, the constant voltage V _ ref tends to increase, and the first transistor Q1 automatically adjusts the voltage difference to compensate so that the constant voltage V _ ref keeps stable output; the voltage value of the constant voltage V _ ref generated by the reference voltage generating unit 181 is within the normal operating voltage range of the second integrated unit U2, the reference voltage generating unit 181 provides a constant voltage value to the second operational amplifier unit 182, and the clamping sub-unit 183 clamps the low voltage flowing through the first operational amplifier unit 13 within the conducting voltage of the sixth diode D6, and the high voltage within the constant voltage provided by the reference voltage generating unit 181, and the third clamping circuit 18 is used to protect the control unit 14, so as to prevent the voltage input by the control unit 14 from being too high or too low to cause the burn-out.
In one embodiment, the second integrated unit U2 is an integrated circuit chip with a constant voltage output, which includes, for example, a LM317 chip, a LM217 chip, an AZ431 chip, and a TL431 chip. By utilizing the constant output voltage of the second integrated unit U2, a constant input voltage can be provided to the tenth resistor R10, and thus a constant voltage V _ ref can be provided to the second op-amp unit 182. In one embodiment, the second op-amp unit 182 is an in-phase proportional operational amplifier U5. In addition, in some possible embodiments, the first power supply terminal VCC1, the second power supply terminal VCC2, and the third power supply terminal VCC3 of the detection circuit 100 are typically 5V, 12V, 24V, or 36V. The voltage value of the first power source terminal VCC1 is not particularly limited herein.
In an embodiment, for example, in this embodiment, the first triode Q1 is an NPN triode, wherein the base of the NPN triode is used as the control terminal of the first triode Q1, the collector thereof is used as the input terminal, and the transmitter thereof is used as the output terminal.
In an embodiment, the detection circuit 100 further includes a second filtering unit 19, the second filtering unit 19 includes a sixth resistor R6 and a second capacitor C2, one end of the sixth resistor R6 is connected to the output terminal of the first operational amplifier unit 13, the other end of the sixth resistor R6 is connected between the second capacitor C2 and the input terminal of the control unit 14, and the other end of the second capacitor C2 is grounded. The second filtering unit 19 is configured to filter ripples in the rectified output voltage of the first operational amplifier unit 13 to obtain a dc voltage signal, reduce a ripple coefficient of the output voltage, make a waveform smoother, and prevent an external environment from generating electromagnetic interference on a voltage signal output by the first operational amplifier unit 13, so as to cause the signal to be unstable, so that the control unit 14 acquires a voltage signal with a smooth waveform, and then detects the temperature of the PT100 temperature sensor according to the acquired voltage signal. In one embodiment, the control unit 14 is a microcontroller, and the microcontroller includes a single chip controller.
In the above-mentioned embodiment, the embodiment of the utility model provides a PT100 temperature sensor's detection circuitry, PT100 temperature sensor's detection circuitry includes that input, constant current source unit, first filter unit, first fortune are put unit and the control unit, implements the embodiment of the utility model provides a PT100 temperature sensor's accuracy can be realized and detection, the utility model discloses an adopted constant current source detection method is simple more reliable, and the feasibility is higher, compares the case operational amplification circuit through the design together and can obtain higher input impedance, and is more accurate, true to acquireing of small signal, and its measurement accuracy is higher. Meanwhile, a multiple clamping protection circuit is designed, so that the safety and reliability of the detection circuit of the PT100 temperature sensor can be effectively improved.
Please refer to fig. 3 to 4, the working principle of the detection circuit 100 of the PT100 temperature sensor according to the present invention will be described in detail. The detection circuit 100 includes an input terminal 15, a constant current source unit 11, a first filtering unit 12, a first operational amplifier unit 13, a control unit 14, a first clamping protection unit 16, a second clamping protection unit 17, a third clamping protection unit 18, and a second filtering unit 19. The constant current source unit 11 includes a first integration unit 111 and a sampling unit 112.
The constant current source unit 11 includes a first integration unit 111 and a sampling unit 112, and a constant input voltage can be provided for the sampling unit 112 by utilizing the characteristic that the first integration unit 111 has a constant output voltage; and then a constant current value required by the detection circuit of the PT100 temperature sensor can be quickly and conveniently debugged by the resistance value of at least one resistor of the sampling unit 112. When the temperature of the PT100 temperature sensor rises, the resistance value of the PT100 temperature sensor becomes large, the current value thereof does not change, and according to the ohm's law, the voltage value of the PT100 temperature sensor becomes large, and after being correspondingly processed by the first filtering unit 12 and the first operational amplifier unit 13, the voltage value is collected by the control unit 14 and then processed by operation, so that the temperature of the PT100 temperature sensor can be read and obtained. The detection circuit 100 of the PT100 temperature sensor prevents the detection circuit 100 from being burnt due to overhigh or overlow input voltage of the PT100 temperature sensor through multiple protection circuit designs such as a first clamping protection circuit 16, a second clamping protection circuit 17, a third clamping protection circuit 18 and the like.
The present invention has been described above with reference to the preferred embodiments, but the present invention is not limited to the above disclosed embodiments, and shall encompass various modifications according to the essence of the present invention.
Claims (10)
1. A detection circuit of a PT100 temperature sensor, comprising: the device comprises an input end, a constant current source unit, a first filtering unit, a first operational amplifier unit and a control unit; wherein,
the input end is the input end of a PT100 temperature sensor, and the output end of the constant current source unit is connected to the input end and used for providing a constant input current for the PT100 temperature sensor; the input end of the first filtering unit is connected to the input end and used for filtering out ripples in the rectified output voltage of the PT100 temperature sensor to obtain a direct-current voltage signal; the positive input end of the first operational amplifier unit is connected to the output end of the first filtering unit and used for amplifying the direct-current voltage signal to obtain high input impedance; and the input end of the control unit is connected to the output end of the first operational amplifier unit and is used for detecting the temperature of the PT100 temperature sensor according to the direct-current voltage signal.
2. The sensing circuit of a PT100 temperature sensor of claim 1, wherein: the constant current source unit comprises a first integrated unit and a sampling unit, wherein the input end of the first integrated unit is connected to a first power supply end, the output end of the first integrated unit is connected to the input end of the sampling unit, the voltage regulating end of the first integrated unit is connected to the input end of the first filtering unit, and the first integrated unit is used for providing a constant input voltage for the sampling unit; the output end of the sampling unit is used as the output end of the constant current source unit and is connected to the input end.
3. The sensing circuit of a PT100 temperature sensor of claim 2, wherein: the first integrated unit is an integrated circuit chip with constant voltage output, the sampling unit comprises at least one resistor, and the at least one resistor is sequentially connected in series and then connected between the output end of the first integrated unit and the input end of the PT100 temperature sensor.
4. The sensing circuit of a PT100 temperature sensor of claim 2, wherein: the detection circuit further comprises a first clamping protection unit, wherein the first clamping protection unit comprises a first diode and a second diode, the cathode of the first diode is connected to the first power supply end, the anode of the first diode is connected to the cathode of the second diode, and the anode of the second diode is connected to the input end of the PT100 temperature sensor.
5. The sensing circuit of a PT100 temperature sensor of claim 1, wherein: the first filtering unit comprises a third resistor and a first capacitor, one end of the third resistor is connected to the input end, the other end of the third resistor is connected between the first capacitor and the positive input end of the first operational amplifier unit, and the other end of the first capacitor is grounded.
6. The sensing circuit of a PT100 temperature sensor of claim 5, wherein: the first operational amplifier unit comprises a fourth resistor, a fifth resistor and an in-phase proportional operational amplifier, wherein a positive input end of the in-phase proportional operational amplifier is used as an input end of the first operational amplifier unit and is connected between the third resistor and the first capacitor, a negative input end of the in-phase proportional operational amplifier is connected to one end of the fourth resistor, and the other end of the fourth resistor is connected between the first capacitor and the ground end; one end of the fifth resistor is connected to the negative input end, the other end of the fifth resistor is connected to the output end of the in-phase proportional operational amplifier, and the output end of the in-phase proportional operational amplifier is used as the output end of the first operational amplifier unit.
7. The sensing circuit of a PT100 temperature sensor of claim 6, wherein: the detection circuit further comprises a second clamping protection unit, wherein the second clamping protection unit comprises a third diode and a fourth diode, the cathode of the third diode is connected between the anode of the fourth diode and the positive input end of the in-phase proportional operational amplifier, the anode of the third diode is grounded, and the cathode of the fourth diode is connected to a second power supply end.
8. The sensing circuit of a PT100 temperature sensor of claim 1, wherein: the detection circuit further comprises a second filtering unit, the second filtering unit comprises a sixth resistor and a second capacitor, one end of the sixth resistor is connected to the output end of the first operational amplifier unit, the other end of the sixth resistor is connected between the second capacitor and the input end of the control unit, and the other end of the second capacitor is grounded.
9. The sensing circuit of a PT100 temperature sensor of claim 8, wherein: the detection circuit further comprises a third clamping protection unit, the third clamping protection unit comprises a clamping subunit, a second operational amplifier unit and a reference voltage generation unit, a positive input end of the second operational amplifier unit is connected to an output end of the reference voltage generation unit, a negative input end of the second operational amplifier unit is connected between the clamping subunit and the second filtering unit, an output end of the second operational amplifier unit is connected to one end of the clamping subunit, and the other end of the clamping subunit is grounded.
10. The sensing circuit of a PT100 temperature sensor of claim 9, wherein: the reference voltage generating unit comprises a second integrated unit, a first triode, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a third capacitor and a fourth capacitor, wherein an input end of the second integrated unit is connected between a control end of the first triode and the seventh resistor, an output end of the second integrated unit is connected between the ninth resistor and the tenth resistor, a voltage adjusting end of the second integrated unit is grounded, the other end of the seventh resistor is connected with one end of the eighth resistor and connected to a third power supply end, the other end of the eighth resistor is connected to an input end of the first triode, an output end of the first triode is connected between the ninth resistor and the fourth capacitor to serve as an output end of the reference voltage generating unit, the other end of the fourth capacitor is grounded, and one end of the third capacitor is connected to the third power supply end, the other end of which is grounded.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821612687.4U CN208780365U (en) | 2018-09-30 | 2018-09-30 | A kind of detection circuit of PT100 temperature sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821612687.4U CN208780365U (en) | 2018-09-30 | 2018-09-30 | A kind of detection circuit of PT100 temperature sensor |
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| CN208780365U true CN208780365U (en) | 2019-04-23 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201821612687.4U Withdrawn - After Issue CN208780365U (en) | 2018-09-30 | 2018-09-30 | A kind of detection circuit of PT100 temperature sensor |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109100052A (en) * | 2018-09-30 | 2018-12-28 | 深圳众城卓越科技有限公司 | A kind of detection circuit of PT100 temperature sensor |
| CN113865781A (en) * | 2021-09-26 | 2021-12-31 | 合肥美的暖通设备有限公司 | Sensor detection circuit, drive control circuit board, electronic equipment and air conditioner |
-
2018
- 2018-09-30 CN CN201821612687.4U patent/CN208780365U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109100052A (en) * | 2018-09-30 | 2018-12-28 | 深圳众城卓越科技有限公司 | A kind of detection circuit of PT100 temperature sensor |
| CN109100052B (en) * | 2018-09-30 | 2024-03-12 | 深圳众城卓越科技有限公司 | PT100 temperature sensor's detection circuitry |
| CN113865781A (en) * | 2021-09-26 | 2021-12-31 | 合肥美的暖通设备有限公司 | Sensor detection circuit, drive control circuit board, electronic equipment and air conditioner |
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