CN109100052A - 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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- CN109100052A CN109100052A CN201811157267.6A CN201811157267A CN109100052A CN 109100052 A CN109100052 A CN 109100052A CN 201811157267 A CN201811157267 A CN 201811157267A CN 109100052 A CN109100052 A CN 109100052A
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Abstract
The invention 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 present invention relates to technical field of temperature measurement, relate more specifically to a kind of detection circuit of PT100 temperature sensor.
Background technique
PT100 temperature sensor be a kind of resistance value vary with temperature and the temperature sensor that changes, have measurement accurate
The features such as degree is high, reliable performance stabilization, high mechanical strength, long life of product, be widely used in meteorology, agricultural, chemical fibre, food,
In the fields such as automobile, household electrical appliance, industrial automation measurement and various laboratory apparatus instrument.Currently, for PT100 temperature sensing
The detection method of device has electric resistance partial pressure detection circuit, Constant current source sense circuit and relative complex has bridge-type differential detection circuit
Deng these detection circuits respectively have advantage and disadvantage, wherein the application of Constant current source sense method is more extensive, and relatively reliable, but there is also
The disadvantages of signal impedance of acquisition is smaller, and detection accuracy is poor, complex circuit designs.
Summary of the invention
Technical problem to be solved by the invention is to provide a kind of detection circuit of PT100 temperature sensor, the detections
The accurate detection of the PT100 temperature sensor may be implemented in circuit, and the detection circuit of the PT100 temperature sensor is intended to solve
The problems such as impedance present in certainly current Constant current source sense method is smaller, and detection accuracy is poor, complex circuit designs.
In order to solve the above technical problem, the present invention provides a kind of detection circuit of PT100 temperature sensor, the detections
Circuit includes input terminal, constant current source unit, the first filter unit, the first amplifier unit and control unit；Wherein, the input
End 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 being described
PT100 temperature sensor provides a constant input current；The input terminal of first filter unit is connected to the input terminal, uses
In filtering out the ripple in the PT100 temperature sensor rectifier output voltage to obtain d. c. voltage signal；First amplifier
The positive input of 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 according to described straight
Galvanic electricity presses the temperature of PT100 temperature sensor described in signal detection.
In the detection circuit of PT100 temperature sensor provided by the invention, the constant current source unit includes first integrated
Unit and sampling unit, the input terminal of first integrated unit are connected to the first power end, and output end is connected to described
The input terminal of sampling unit, voltage adjustable side are connected to the input terminal of first filter unit, first integrated unit
For providing a constant input voltage for the sampling unit；The output end of the sampling unit is as the constant current source unit
Output end is connected to the input terminal.
In the detection circuit of PT100 temperature sensor provided by the invention, first integrated unit is with constant
The IC chip of voltage output, the sampling unit include at least one resistance, at least one described resistance is sequentially connected in series
It is connected between the output end of first integrated unit and the input terminal of the PT100 temperature sensor afterwards.
In the detection circuit of PT100 temperature sensor provided by the invention, the detection circuit further includes the first clamper
Protection location, the first clamper protection location include first diode and the second diode, the first diode cathode
It is connected to first power end, anode is connected to the cathode of second diode, and the anode of second diode connects
It is connected to the input terminal of PT100 temperature sensor.
In the detection circuit of PT100 temperature sensor provided by the invention, first filter unit includes third electricity
Resistance and first capacitor, one end of the 3rd resistor are connected to the input terminal, and the other end is connected to the first capacitor
Between the positive input of the first amplifier unit, the other end of the first capacitor is grounded.
In the detection circuit of PT100 temperature sensor provided by the invention, the first amplifier unit includes the 4th electricity
Resistance, the 5th resistance and in-phase proportion operational amplifier, described in the positive input of the in-phase proportion operational amplifier is used as
The input terminal of first amplifier unit is connected between the 3rd resistor and the first capacitor, and negative input is connected to
The other end of one end of four resistance, the 4th resistance is connected between the first capacitor and ground terminal；5th resistance
One end is connected to the negative input, and the other end is connected to the output end of the in-phase proportion operational amplifier, described same
Output end of the output end of Phase Proportion operational amplifier as the first amplifier unit.
In the detection circuit of PT100 temperature sensor provided by the invention, the detection circuit further includes the second clamper
Protection location, the second clamper protection location include third diode and the 4th diode, the yin of the third diode
Pole is connected between the anode of the 4th diode and the positive input of the in-phase proportion operational amplifier, and anode connects
The cathode on ground, the 4th diode is connected to second source end.
In the detection circuit of PT100 temperature sensor provided by the invention, the detection circuit further includes the second filtering
Unit, second filter unit include the 6th resistance and the second capacitor, and one end of the 6th resistance is connected to described the
The output end of one amplifier unit, the other end is connected between second capacitor and the input terminal of described control unit, described
The other end of second capacitor is grounded.
In the detection circuit of PT100 temperature sensor provided by the invention, the detection circuit further includes third clamper
Protection location, the third clamper protection location include clamper subelement, the second amplifier unit and reference voltage generation unit,
The positive input of the second amplifier unit is connected to the output end of the reference voltage generation unit, and negative input connects
It being connected between the clamper subelement and second filter unit, output end is connected to one end of the clamper subelement,
The other end of the clamper subelement is grounded.
In the detection circuit of PT100 temperature sensor provided by the invention, the reference voltage generation unit includes the
Two integrated units, the first triode, the 7th resistance, the 8th resistance, the 9th resistance, the tenth resistance, third capacitor and the 4th electricity
Holding, wherein the input terminal of second integrated unit is connected between the control terminal and the 7th resistance of first triode,
Its output end is connected between the 9th resistance and the tenth resistance, voltage adjustable side ground connection, the 7th resistance it is another
End is connected with one end of the 8th resistance and is connected to third power end, and the other end of the 8th resistance is connected to described the
The input terminal of one triode, the output end of first triode be connected between the 9th resistance and the 4th capacitor with
As the output end of the reference voltage generation unit, the other end of the 4th capacitor is grounded, one end of the third capacitor
It is connected to the third power end, other end ground connection.
The embodiment of the invention provides a kind of detection circuits of PT100 temperature sensor.Implementing the embodiment of the present invention can be with
Realize the accurate detection of PT100 temperature sensor, Constant current source sense method used by the embodiment of the present invention is simpler reliable, can
Row is higher, can get higher input impedance by designing an in-phase proportion operational amplification circuit, more to the acquisition of small signal
Add accurate, true, measurement accuracy is higher.
Through the following description and in conjunction with the attached drawings, the present invention will become more fully apparent, these attached drawings are used to explain the present invention
Embodiment.
Detailed description of the invention
Fig. 1 is a kind of structural block diagram of the detection circuit for PT100 temperature sensor that first embodiment of the invention provides；
Fig. 2 is a kind of structural block diagram of the detection circuit for PT100 temperature sensor that second embodiment of the invention provides；
Fig. 3 is a kind of frame principle figure of the detection circuit for PT100 temperature sensor that second embodiment of the invention provides；
And
Fig. 4 is a kind of physical circuit figure of the detection circuit for PT100 temperature sensor that second embodiment of the invention provides.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, is clearly and completely retouched to the technical solution in embodiment
It states, similar reference numerals represent similar component in attached drawing.Obviously, will be described below embodiment is only the present invention one
Divide embodiment, instead of all the embodiments.Based on the embodiments of the present invention, those of ordinary skill in the art are not making
Every other embodiment obtained, shall fall within the protection scope of the present invention under the premise of creative work.
It should be appreciated that ought use in this specification and in the appended claims, term " includes " and "comprising" instruction
Described feature, entirety, step, operation, the presence of element and/or component, but one or more of the other feature, whole is not precluded
Body, step, operation, the presence or addition of element, component and/or its set.
It is also understood that herein term as used in this specification merely for the sake of for the purpose of describing particular embodiments and
It is not intended to limit the present invention.As description of the invention and it is used in the attached claims, unless context
Other situations are clearly indicated, otherwise " one " of singular, "one" and "the" are intended to include plural form.
It will be further appreciated that the term "and/or" used in this specification and in the appended claims refers to phase
It is associated with any combination and all possible combinations of one or more of item listed, and including these combinations.
The present invention provides a kind of detection circuits of PT100 temperature sensor.The detection circuit includes input terminal, constant current
Source unit, the first filter unit, the first amplifier unit and control unit；Wherein, the input terminal is PT100 temperature sensor
Input terminal, the output end of the constant current source unit is connected to the input terminal, for providing for the PT100 temperature sensor
One constant input current；The input terminal of first filter unit is connected to the input terminal, for filtering out the PT100 temperature
Ripple in sensor rectifier output voltage is to obtain d. c. voltage signal；The positive input of the first amplifier unit connects
To the output end of first filter unit, for amplifying the d. c. voltage signal to obtain high input impedance；The control
The input terminal of unit is connected to the output end of the first amplifier unit, for according to d. c. voltage signal detection
The temperature of PT100 temperature sensor.Specifically, one simple and reliable perseverance of the measurement circuit design of the PT100 temperature sensor
Source unit is flowed, the forward direction that a constant current caused by the constant current source unit is output to the PT100 temperature sensor is defeated
Enter end to obtain a constant voltage signal, and the constant voltage signal is output to the first filter unit and the first amplifier unit
It is filtered and enhanced processing, the constant voltage signal is finally input to described control unit, to realize the PT100 temperature
The detection for spending the temperature of sensor, effectively can accurately detect the PT100 temperature sensor, solve constant current in the prior art
The problems such as acquisition signal impedance present in the detection method of source is low, precision is lower and complex circuit designs, and the present invention is implemented
Example circuit is simple, and cost of implementation is low, usability and practicality with higher.
Referring to Figure 1, be first embodiment of the invention provide a kind of PT100 temperature sensor detection circuit knot
Structure block diagram.As shown, the detection circuit 100 includes an input terminal 15, a constant current source unit 11, one first filter unit
12, one first amplifier unit 13 and a control unit 14, wherein the input terminal 15 is the input of PT100 temperature sensor
End, the output end of the constant current source unit 11 is connected to the input terminal 15, for providing one for the PT100 temperature sensor
Constant input current；The input terminal of first filter unit 12 is connected to the input terminal 15, for filtering out the PT100 temperature
The ripple in sensor rectifier output voltage is spent to obtain d. c. voltage signal, prevents external environment from passing to the PT100 temperature
The voltage signal of sensor output generates electromagnetic interference, and then leads to the jitter；The forward direction of the first amplifier unit 13
Input terminal is connected to the output end of first filter unit 12, and high input resistance is obtained for amplifying the d. c. voltage signal
It is anti-；The input terminal of described control unit 14 is connected to the output end of the first amplifier unit 13, for according to the direct current
Press the temperature of PT100 temperature sensor described in signal detection.
Fig. 2~Fig. 4 is referred to, Fig. 2 is a kind of detection electricity for PT100 temperature sensor that second embodiment of the invention provides
The structural block diagram on road；Fig. 3 is that a kind of box of the detection circuit for PT100 temperature sensor that second embodiment of the invention provides is former
Reason figure；Fig. 4 is a kind of physical circuit figure of the detection circuit for PT100 temperature sensor that second embodiment of the invention provides.Such as
Shown in Fig. 2, the detection circuit of the PT100 temperature sensor further includes the first clamper protection location 15, the second clamper protection list
Member 17, third clamper protection location 18 and the second filter unit 19, in the present embodiment, designed multiple clamp circuit meeting
Keep the detection circuit of the PT100 temperature sensor relatively reliable, safe.
In one embodiment, as shown in figs. 34, the constant current source unit 11 includes the first integrated unit 111 and sampling
Unit 112, the input terminal of first integrated unit 111 are connected to the first power end VCC1, and output end is connected to described adopt
The input terminal of sample unit 112, voltage adjustable side are connected to the input terminal of first filter unit 12, and described first is integrated single
Member 111 is for providing a constant input voltage for the sampling unit 12；The output end of the sampling unit 12 is as the perseverance
The output end of stream source unit 11 is connected to the input terminal 15.In one embodiment, first integrated unit 111 is with perseverance
The IC chip of constant voltage output comprising such as LM317 chip, LM217 chip, AZ431 chip and TL431 core
Piece.There is the characteristic of constant output voltage using first integrated unit 111, one can be provided for the sampling unit 112
Constant input voltage.In one embodiment, such as in the present embodiment, it is integrated as described first that such as LM317 chip can be used
Unit 111, the LM317 chip include three pins, i.e. an input pin, an output pin and a voltage adjustment pin.
Wherein, the input pin is connected to first power end, and the output pin is connected to the sampling unit 112, described
Voltage adjustment pin is connected to the input terminal of the first filter unit 12, wherein the input pin and output pin will connect over the ground
Filter capacitor, i.e., the described input pin are connected between the first power end VCC1 and the 6th capacitor C6, the 6th capacitor
The other end of C6 is grounded, and the output pin is connected between the sampling unit 112 and the 5th capacitor C5, the 5th capacitor
The other end of C5 is grounded.The sampling unit 112 includes at least one resistance, at least one described resistance connects after being sequentially connected in series
Between the output end of first integrated unit 111 and the input terminal of the PT100 temperature sensor.In one embodiment,
As shown in figure 4, the sampling unit 112 includes first resistor R1 and second resistance R2, the first resistor R1 and the second electricity
Resistance R2 is connected to the output end of first integrated unit 111 and the input terminal of the PT100 temperature sensor after being sequentially connected in series
Between, the PT100 temperature can quickly and easily be debugged out by the resistance value cooperation of the first resistor R1 and second resistance R2
Spend a Constant Electric Current flow valuve required for the detection circuit of sensor.
In one embodiment, first filter unit 12 includes 3rd resistor R3 and first capacitor C1, the third
One end of resistance R3 is connected to the input terminal 15, and the other end is connected to the first capacitor C1 and the first amplifier unit
Between 13 positive input, the other end of the first capacitor C1 is grounded；First filter unit 12 is described for filtering out
Ripple in PT100 temperature sensor rectifier output voltage reduces the ripple factor of output voltage to obtain d. c. voltage signal,
So that waveform is become smoother, prevents external environment from generating electromagnetism to the voltage signal that the PT100 temperature sensor exports dry
It disturbs, and then leads to the jitter；Or the positive and negative anodes of PT100 temperature sensor described in client's misconnection are prevented, burn out institute
State PT100 temperature sensor.
In one embodiment, the first amplifier unit 13 includes the 4th resistance R4, the 5th resistance R5 and in-phase proportion
Input of the positive input of operational amplifier U4, the in-phase proportion operational amplifier U4 as the first amplifier unit 13
End is connected between the 3rd resistor R3 and the first capacitor C1, and negative input is connected to the one of the 4th resistance R4
End, the other end of the 4th resistance R4 are connected between the first capacitor C1 and ground terminal GND；The one of the 5th resistance R5
End is connected to the negative input, and the other end is connected to the output end of the in-phase proportion operational amplifier U4, described same
Output end of the U4 output end of Phase Proportion operational amplifier as the first amplifier unit 13.Using in-phase proportion operation amplifier
The available higher input impedance of device U4, it is more accurate to the acquisition of small signal, true, substantially increase temperature measurement accuracy.
In one embodiment, as shown in figs. 34, the detection circuit 100 further includes the first clamper protection location 16, institute
Stating the first clamper protection location 16 includes first diode D1 and the second diode D2, the first diode D1 cathode connection
To the first power end VCC1, anode is connected to the cathode of the second diode D2, the sun of the second diode D2
Pole is connected to the input terminal 15 of PT100 temperature sensor.Described in the first diode D1 and the second diode D2 composition
15 overvoltage clamping circuit of PT100 temperature sensor inputs, first clamping protective circuit 16 are used to work as the PT100 temperature
When sensor high input voltage by the input voltage clamper of the PT100 temperature sensor the first power end VCC1 state,
The input voltage of the i.e. described PT100 temperature sensor is less than or equal to the voltage value of the first power end VCC1, first pincers
Position protection circuit 16 is for protecting the PT100 temperature sensor.
In one embodiment, as shown in figs. 34, the detection circuit 100 further includes the second clamper protection location 17, institute
Stating the second clamper protection location 17 includes third diode D3 and the 4th diode D4, and the cathode of the third diode D3 connects
It is connected between the anode of the 4th diode D4 and the positive input of the in-phase proportion operational amplifier U4, anode connects
The cathode on ground, the 4th diode D4 is connected to second source end VCC2.If second clamping protective circuit 17 is for flowing
Voltage through first filter unit 12 be high voltage, by the high voltage clamper second source end VCC2 state；If stream
Voltage through first filter unit 12 be low-voltage, by the low-voltage clamper the conducting voltage of third diode D3 shape
State, that is, the forward voltage for being input to the first amplifier unit 13 is less than or equal to the voltage value of the second source end VCC2, defeated
Enter the voltage value of the conducting voltage to the negative voltage of the first amplifier unit 13 less than or equal to the third diode D3, institute
The second clamping protective circuit 17 is stated for protecting the first amplifier unit 13, prevents the first amplifier unit 13 from being inputted
Overtension is too low and it is caused to burn.
In one embodiment, the detection circuit 100 further includes third clamper protection location 18, the third clamper protection
Unit 18 includes reference voltage generation unit 181, the second amplifier unit 182 and clamper subelement 183, the second amplifier list
The positive input of member 13 is connected to the output end of the reference voltage generation unit 181, and negative input is connected to described
Between clamper subelement 183 and second filter unit 12, output end is connected to one end of the clamper subelement 183,
The other end of the clamper subelement 183 is grounded.In one embodiment, such as in the present embodiment, the reference voltage generates single
Member 181 includes the second integrated unit U2, the first triode Q1, the 7th resistance R7, the 8th resistance R8, the 9th resistance R9, the tenth electricity
Hinder R10, third capacitor C3 and the 4th capacitor C4, wherein the input terminal of the second integrated unit U2 is connected to described first
Between the control terminal of triode Q1 and the 7th resistance R7, output end is connected to the 9th resistance R9 and the tenth resistance R10
Between, voltage adjustable side is grounded GND, and the other end of the 7th resistance R7 is connected and connects with one end of the 8th resistance R8
It is connected to third power end VCC3, the other end of the 8th resistance R8 is connected to the input terminal of the first triode Q1, described
The output end of first triode Q1 is connected between the 9th resistance R9 and the 4th capacitor C4 using electric as the reference
The output end of generation unit 181 is pressed, the other end ground connection of the 4th capacitor C4, one end of the third capacitor C3 is connected to institute
State third power end VCC3, other end ground connection.Wherein, pass through the third power end VCC3, the 7th resistance R7 and the 8th
Resistance R8 cooperates so that the first triode Q1 work is on state, so that the reference voltage generation unit
181 generate a constant voltage V_ref, wherein when the electric current of the second amplifier unit 182 increases, the constant voltage V_
Ref tends to reduce, and the first triode Q1 automatic adjustment pressure difference compensates so that the constant voltage V_ref keeps steady
Fixed output；When the electric current of the second amplifier unit 182 is reduced, the constant voltage V_ref tends to increase, and described first
Triode Q1 automatic adjustment pressure difference compensates so that the constant voltage V_ref keeps stablizing output；Wherein, described with reference to electricity
Press the voltage value of constant voltage V_ref caused by generation unit 181 in the normal working voltage of the second integrated unit U2
In range, the reference voltage generation unit 181 is that the second amplifier unit 182 provides a constant voltage values, and passing through should
Clamper subelement 183 will flow through conducting voltage of the low-voltage clamper in the 6th diode D6 of the first amplifier unit 13
Interior, high voltage clamper is in the constant voltage provided by the reference voltage generation unit 181, the third clamping protective circuit
18 for protecting described control unit 14, the overtension that prevents described control unit 14 from being inputted or too low and lead to its burning
It ruins.
In one embodiment, the second integrated unit U2 is the IC chip exported with constant voltage, packet
Include such as LM317 chip, LM217 chip, AZ431 chip and TL431 chip.There is perseverance using the second integrated unit U2
Determine the characteristic of output voltage, a constant input voltage can be provided for the tenth resistance R10, and then is the second amplifier list
Member 182 provides a constant voltage values V_ref.In one embodiment, the second amplifier unit 182 is in-phase proportion operation amplifier
Device U5.In addition, in some possible embodiments, the first power end VCC1, the second source end VCC2 of the detection circuit 100
And third power end VCC3 is usually 5V, 12V, 24V or 36V.Herein not to the voltage value of the first power end VCC1
Make concrete restriction.
In one embodiment, such as in the present embodiment, the first triode Q1 is NPN triode, wherein the NPN
Control terminal of the base stage of triode as the first triode Q1, collector is as input terminal, and transmitter is as output end.
In one embodiment, the detection circuit 100 further includes the second filter unit 19, and second filter unit 19 wraps
The 6th resistance R6 and the second capacitor C2 is included, one end of the 6th resistance R6 is connected to the output of the first amplifier unit 13
End, the other end are connected between the second capacitor C2 and the input terminal of described control unit 14, the second capacitor C2's
Other end ground connection.Second filter unit 19 be used to filter out ripple in 13 rectifier output voltage of the first amplifier unit with
D. c. voltage signal is obtained, the ripple factor of output voltage is reduced, so that waveform is become smoother, prevents external environment to described
The voltage signal of first amplifier unit 13 output generates electromagnetic interference, and then leads to the jitter, so that the control is single
Member 14 collects the smooth voltage signal of a waveform, and then detects the PT100 temperature sensing according to collected voltage signal
The temperature of device.In one embodiment, described control unit 14 is a microcontroller, and the microcontroller includes single-chip microcontroller control
Device.
In the above-described embodiments, described the embodiment of the invention provides a kind of detection circuit of PT100 temperature sensor
The detection circuit of PT100 temperature sensor include input terminal, constant current source unit, the first filter unit, the first amplifier unit and
Control unit, implementing the embodiment of the present invention may be implemented the accurate detection of PT100 temperature sensor, and the embodiment of the present invention is used
Constant current source sense method it is simpler reliable, feasibility is higher, by one in-phase proportion operational amplification circuit of design can get compared with
High input impedance, more accurate to the acquisition of small signal, true, measurement accuracy is higher.Meanwhile multiple clamper has also been devised
Circuit is protected, can effectively improve the safety and reliability of the detection circuit of PT100 temperature sensor.
Continuing with referring to Fig. 3~4, the following detailed description of a kind of detection electricity of PT100 temperature sensor provided by the invention
The working principle on road 100.The detection circuit 100 includes an input terminal 15, a constant current source unit 11, one first filter unit
12, one first amplifier unit 13, a control unit 14, one first clamper protection location 16, one second clamper protection location 17, one
Third clamper protection location 18 and one second filter unit 19.Wherein, the constant current source unit 11 includes the first integrated unit
111 and sampling unit 112.
The constant current source unit 11 includes the first integrated unit 111 and sampling unit 112, utilizes the described first integrated list
Characteristic of the member 111 with constant output voltage can provide a constant input voltage for the sampling unit 112；And then lead to again
The resistance value cooperation for crossing at least one resistance of the sampling unit 112 can quickly and easily debug out the PT100 temperature and pass
A Constant Electric Current flow valuve required for the detection circuit of sensor.It is described when the temperature of the PT100 temperature sensor increases
The resistance value of PT100 temperature sensor becomes larger, and current value is constant, according to Ohm's law, the voltage of the PT100 temperature sensor
Value becomes larger, and after the first filter unit 12 and the first amplifier unit 13 carry out respective handling, then is acquired and is passed through by control unit 14
Calculation process, and then the temperature for obtaining the PT100 temperature sensor can be read.The detection circuit 100 of PT100 temperature sensor
Pass through the multiple protective circuits such as the first clamping protective circuit 16, the second clamping protective circuit 17 and third clamping protective circuit 18
Design prevents from causing the detection circuit 100 to be burned out because the input voltage of the PT100 temperature sensor is excessively high or too low.
Combining preferred embodiment above, invention has been described, but the invention is not limited to implementations disclosed above
Example, and should cover and various modify according to the essence of the present invention.
Claims (10)
1. a kind of detection circuit of PT100 temperature sensor characterized by comprising input terminal, constant current source unit, the first filter
Wave 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
End, 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 direct current
Press signal to obtain high input impedance；The input terminal of described control unit is connected to the output end of the first amplifier unit, uses
In the temperature for detecting the PT100 temperature sensor according to the d. c. voltage signal.
2. the detection circuit of PT100 temperature sensor according to claim 1, it is characterised in that: the constant current source unit
Including the first integrated unit and sampling unit, the input terminal of first integrated unit is connected to the first power end, output
End is connected to the input terminal of the sampling unit, and voltage adjustable side is connected to the input terminal of first filter unit, described
First integrated unit is used to provide a constant input voltage for the sampling unit；Described in the output end of the sampling unit is used as
The output end of constant current source unit is connected to the input terminal.
3. the detection circuit of PT100 temperature sensor according to claim 2, it is characterised in that: described first is integrated single
Member is the IC chip that exports with constant voltage, and the sampling unit includes at least one resistance, it is described at least one
Resistance be connected to after being sequentially connected in series first integrated unit output end and the PT100 temperature sensor input terminal it
Between.
4. the detection circuit of PT100 temperature sensor according to claim 2, it is characterised in that: the detection circuit is also
Including the first clamper protection location, the first clamper protection location includes first diode and the second diode, and described
One diode cathode is connected to first power end, and anode is connected to the cathode of second diode, and the described 2nd 2
The anode of pole pipe is connected to the input terminal of PT100 temperature sensor.
5. the detection circuit of PT100 temperature sensor according to claim 1, it is characterised in that: first filtering is single
Member includes 3rd resistor and first capacitor, and one end of the 3rd resistor is connected to the input terminal, and the other end is connected to
Between the first capacitor and the positive input of the first amplifier unit, the other end of the first capacitor is grounded.
6. the detection circuit of PT100 temperature sensor according to claim 5, it is characterised in that: the first amplifier list
Member includes the 4th resistance, the 5th resistance and in-phase proportion operational amplifier, and the forward direction of the in-phase proportion operational amplifier is defeated
The input terminal for entering end as the first amplifier unit is connected between the 3rd resistor and the first capacitor, and negative sense is defeated
Enter one end that end is connected to the 4th resistance, the other end of the 4th resistance is connected between the first capacitor and ground terminal；Institute
The one end for stating the 5th resistance is connected to the negative input, and the other end is connected to the defeated of the in-phase proportion operational amplifier
Outlet, output end of the output end of the in-phase proportion operational amplifier as the first amplifier unit.
7. the detection circuit of PT100 temperature sensor according to claim 6, it is characterised in that: the detection circuit is also
Including the second clamper protection location, the second clamper protection location includes third diode and the 4th diode, and described
The cathode of three diodes is connected to the anode of the 4th diode and the positive input of the in-phase proportion operational amplifier
Between, the cathode of plus earth, the 4th diode is connected to second source end.
8. the detection circuit of PT100 temperature sensor according to claim 1, it is characterised in that: the detection circuit is also
Including the second filter unit, second filter unit includes the 6th resistance and the second capacitor, one end of the 6th resistance
It is connected to the output end of the first amplifier unit, the other end is connected to the input of second capacitor and described control unit
Between end, the other end of second capacitor is grounded.
9. the detection circuit of PT100 temperature sensor according to claim 8, it is characterised in that: the detection circuit is also
Including third clamper protection location, the third clamper protection location includes clamper subelement, the second amplifier unit and reference
Voltage generating unit, the positive input of the second amplifier unit are connected to the output end of the reference voltage generation unit,
Its negative input is connected between the clamper subelement and second filter unit, and output end is connected to the clamper
One end of subelement, the other end ground connection of the clamper subelement.
10. the detection circuit of PT100 temperature sensor according to claim 9, it is characterised in that: the reference voltage is raw
It include the second integrated unit, the first triode, the 7th resistance, the 8th resistance, the 9th resistance, the tenth resistance, third electricity at unit
Hold and the 4th capacitor, wherein the input terminal of second integrated unit be connected to first triode control terminal and
Between 7th resistance, output end is connected between the 9th resistance and the tenth resistance, voltage adjustable side ground connection, and described the
The other end of seven resistance is connected with one end of the 8th resistance and is connected to third power end, the other end of the 8th resistance
It is connected to the input terminal of first triode, the output end of first triode is connected to the 9th resistance and described the
Using the output end as the reference voltage generation unit between four capacitors, the other end of the 4th capacitor is grounded, and described the
One end of three capacitors is connected to the third power end, other end ground connection.
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| CN201811157267.6A CN109100052B (en) | 2018-09-30 | 2018-09-30 | PT100 temperature sensor's detection circuitry |
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| CN111121999A (en) * | 2019-11-13 | 2020-05-08 | 江苏弘历电气有限公司 | Temperature measuring circuit of PT100 resistance core with constant current source |
| CN111383781A (en) * | 2020-03-02 | 2020-07-07 | 中广核工程有限公司 | Simulation acquisition device for temperature jump time of thermal resistor and circuit thereof |
| 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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| CN109100052B (en) | 2024-03-12 |
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