CN110260773A - A kind of preposition conditioning device of the current vortex sensor of Low Drift Temperature - Google Patents
A kind of preposition conditioning device of the current vortex sensor of Low Drift Temperature Download PDFInfo
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- CN110260773A CN110260773A CN201910427333.5A CN201910427333A CN110260773A CN 110260773 A CN110260773 A CN 110260773A CN 201910427333 A CN201910427333 A CN 201910427333A CN 110260773 A CN110260773 A CN 110260773A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/14—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring distance or clearance between spaced objects or spaced apertures
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03G—CONTROL OF AMPLIFICATION
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Abstract
The invention proposes a kind of preposition conditioning devices of the current vortex sensor of Low Drift Temperature, comprising: the output end of sine signal source generative circuit and the input terminal of automatic gain controller connect；The output end of automatic gain controller and one end of detection circuit connect, for carrying out amplitude control, output sine wave exciting signal to detection circuit to the sine wave exciting signal from sine signal source generative circuit；Detection circuit includes: divider resistance, probe coil, compensating electric capacity array；Precise rectification circuit rectifies the voltage for carrying out self-detection circuit received, generates direct current signal；The input terminal of signal amplification circuit amplifies processing to the direct current signal received, exports the probe that amplified analog signal is coupled to current vortex sensor.The present invention shows extremely low temperature drift, exports under high-gain reliable and stable, improves current vortex front end circuit performance, is suitable for nanoscale precision measure application.
Description
Technical field
The present invention relates to current vortex technical field, in particular to a kind of preposition conditioning dress of the current vortex sensor of Low Drift Temperature
It sets.
Background technique
The bulk gold that current vortex refers to the reguline metal conductor being placed in variation magnetic field or makees cutting magnetic line in magnetic field
The phenomenon that belonging to conductor, then will generating gyrate induced current in this reguline metal conductor.Fig. 1 shows current vortex effect
It answers.Wherein, H1 is the alternating magnetic field that sine-wave excitation is applied to probe coil generation, goes out electric whirlpool in metallic conductor surface induction
Flow I2, the alternating magnetic field generated is H2, influence the amplitude and phase of probe coil I1, when probe coil and metallic conductor away from
When changing from d, I1 changes therewith, measures the amplitude and phase information of I1, i.e., extractable distance d information.
The direct measurement to displacement may be implemented using the sensor that eddy current effect makes, by setting to driving frequency
It is fixed can also the thickness to certain material film directly measured, and can measure indirectly vibration, temperature, stress, speed with
And material damage etc., eddy current measuring method have non-contact, not loud by greasy dirt light and dust interference, high sensitivity, frequency
The advantages that answering range wide.
Current vortex sensor feature: the electric vortex sensor device of complete set mainly includes probe, extension cable, preposition
Device and attachment.Probe type is divided into unicoil, twin coil and coil array formula etc., and probe and fore-lying device according to the present invention are
Single line ring type.Sensor probe diameter is smaller, and eddy current effect measurement range is smaller, and resolution ratio is higher；In ranging application, pass
Sensor range is generally the 1/2 of probe diameter, and sensor according to the present invention is the accurate short range distance of minor diameter probe
Or film thickness measuring sensor.
Current vortex sensor precision is affected by many factors, mainly has: probe diameter, the compensation of probe resonant state, conditioning
Circuit gain, circuit temperature drift etc..The precision property of the preposition conditioning device of the current vortex sensor of identical topological structure is by it
Circuit temperature drift characteristic influences significantly, and temperature drift is bigger, and sensor accuracy is lower.Circuit topology designed by the present invention and
Parts selection method has the advantages that temperature drift is extremely low.
Resonance compensation circuit of popping one's head in uses LC antiresonant circuit.It is in parallel in inductance, capacitor and outer plus AC power source
In oscillation circuit, when the frequency of additional power source is equal to the intrinsic frequency in circuit, resonance just occurs for circuit.This resonance
Parallel resonance is done, as shown in Figure 2.
Current vortex sensor probe is inductance coil L, by carrying out frequency compensation to coils from parallel connection of coils capacitor C, makes coil
Parallel resonance occurs under driving frequency, it is maximum to generate electric current I variable quantity when being vortexed variation, and transducer sensitivity is most at this time
It is high.
The product of current vortex sensor probe batch making, different probe parameters have fine difference, in practical applications, need
Compensating electric capacity is matched according to probe parameter, reach resonance purpose, wherein resonant capacitance type selecting is more crucial, influences compensating coefficient
Stability, finally influence performance.
The prior art uses following two solution, but all has some disadvantages:
(1) the preposition conditioning device scheme of cheap current vortex sensor: the driver unit of leading sensor conditioning device uses
Multivibrator generates the square-wave signal of specific frequency, and output frequency is unstable, and is shaped as near sinusoidal using passive filtering
Wave signal, circuit do not have active leveling circuit (AGC), and signal couples directly to sensor probe, complete excitation.
Oscillator output signal is poor through the resulting sinusoidal amplitude stability of passive filter circuit shaping, while without certainly
Dynamic fixed amplitude circuit, the signal amplitude of driving source is larger with temperature drift, influences sensor outputs, is unable to complete accurate measurement
Task.
Multivibrator output signal frequency is unstable, tired to bringing in subsequent conditioning circuit to the compensation of probe resonance frequency
Difficulty as uses fixed compensation capacitor, can not influence transducer sensitivity with the exciting signal source resonance of variation and output is stablized
Property.
(2) the preposition conditioning device scheme of high precision electro eddy current sensor: being exported using quartz oscillator shaping, output
Frequency is more stable, has active leveling circuit (AGC), and circuit element causes agc circuit to still remain smaller temperature without special type selecting
Drift.
Although agc circuit can to export relatively stable, when extraneous temperature change is larger, can not be competent to precision
More demanding electric eddy current measurement occasion.
Summary of the invention
The purpose of the present invention aims to solve at least one of described technological deficiency.
For this purpose, it is an object of the invention to propose a kind of preposition conditioning device of the current vortex sensor of Low Drift Temperature.
To achieve the goals above, the embodiment of the present invention provides a kind of preposition conditioning dress of current vortex sensor of Low Drift Temperature
It sets, comprising: sine wave source generative circuit, automatic gain controller, detection circuit, precise rectification circuit and signal amplification electricity
Road, wherein
The output end of the sine signal source generative circuit is connect with the input terminal of the automatic gain controller, for giving birth to
At circuit output sine wave exciting signal to the automatic gain controller；
The output end of the automatic gain controller is connect with one end of the detection circuit, for from the sine
The sine wave exciting signal of signal source generative circuit carries out amplitude control, output sine wave exciting signal to the detection circuit；
The detection circuit includes: divider resistance, probe coil, compensating electric capacity array, wherein the divider resistance
The other end connect with one end of the probe coil, the other end of probe coil ground connection, the compensating electric capacity array with
The probe coil is connected in parallel, and receives the sine wave exciting signal from the automatic gain controller, the probe respectively
Resonance occurs for coil and compensating electric capacity array in parallel, after eddy current effect occurs for the probe coil, the probe coil two
The voltage at end generates variation, the voltage output to the precise rectification circuit；
The input terminal of the precise rectification circuit is connect with the detection circuit, for coming from the detection to what is received
The voltage of circuit is rectified, and direct current signal is generated；
The input terminal of the signal amplification circuit connect with the output end of the precise rectification circuit, for receiving
Direct current signal amplifies processing, exports the probe that amplified analog signal is coupled to current vortex sensor,
Wherein, the sine wave source generative circuit, automatic gain controller, detection circuit, precise rectification circuit and
Signal amplification circuit is all made of the realization of Low Drift Temperature device.
Further, the sine wave source generative circuit uses Direct Digital Frequency Synthesizers DDS.
Further, the automatic gain controller includes: variable gain amplifier chip, passive filter circuit, built-in essence
Close rectification circuit and instrument amplifier, wherein
The variable gain amplifier chip is for amplifying sine wave exciting signal；
The input terminal of the built-in precise rectification circuit is connect with the output end of the variable gain amplifier chip, is used for
The amplitude of the sine wave exciting signal is obtained, the electricity directly proportional to signal amplitude is then obtained by the passive filter circuit
Press output signal；
The input terminal of the instrument amplifier is connect with the passive filter circuit, for the voltage output signal with
Reference voltage is compared, and comparison result is fed back to the input terminal of the variable gain amplifier, by the variable gain
The amplitude that amplifier adjusts output signal is steady state value.
Further, the built-in precise rectification circuit includes: that the first operational amplifier, the first rectifier diode and second are whole
Diode is flowed, the negative input of the operational amplifier connects the output end of the variable gain amplifier, first operation
The positive input of amplifier is grounded, and the output of first operational amplifier terminates the forward direction of second rectifier diode
End, the negative sense of second rectifier diode terminates the passive filter circuit, defeated in the negative sense of first operational amplifier
Enter and connect first rectifier diode between end and output end on feedback network, wherein first operational amplifier uses
Low Drift Temperature operational amplifier.
Further, the precise rectification circuit includes: second operational amplifier, third rectifier diode and the 4th rectification two
Pole pipe, the positive input of the second operational amplifier connect the compensating electric capacity array, the second operational amplifier
Negative input ground connection, between the negative input and output end of the second operational amplifier on feedback network described in connection
Third rectifier diode and the 4th rectifier diode, precise rectification circuit sine described in the signal at search coil both ends swash
It encourages signal to be rectified, obtains positive half-wave unipolar signal, be shaped as direct current signal by passive filtering network, wherein described
Second operational amplifier uses Low Drift Temperature operational amplifier.
Further, buffer, institute are further provided between the precise rectification circuit and the signal amplification circuit
Buffer is stated using Low Drift Temperature operational amplifier, the input of the buffer connects the output end of the precise rectification circuit, described
The input of buffer terminates the input terminal of the signal amplification circuit.
Further, the signal amplification circuit includes: third operational amplifier, feedback resistance and toggle switch, wherein institute
The each access and a feedback resistance for stating toggle switch are connected in series, and gate corresponding feedback by the toggle switch
Resistance, the dial-up and the feedback resistance are set to anti-between the negative input and output end of the third operational amplifier
Feedthrough road, wherein the third operational amplifier uses Low Drift Temperature operational amplifier, and the feedback resistance is low using high-precision
Temperature drift resistance device.
The preposition conditioning device of the current vortex sensor of Low Drift Temperature according to an embodiment of the present invention believes the sinusoidal excitation of generation
It number is applied in the detection circuit that divider resistance, probe coil and compensating electric capacity array are constituted, probe coil and compensating electric capacity are simultaneously
Resonance occurs for connection, and pumping signal is undertaken together with divider resistance, after eddy current effect occurs for probe coil, coil both ends
Voltage generates faint variation, which is positive and negative bipolar voltage, rectifies to obtain positive half-wave unipolarity letter by precise rectification circuit
Number, it is shaped as direct current signal by passive filtering network, output is then amplified by the operational amplification circuit of fixed gain, transfers to it
His acquisition system acquisition process.
In order to realize that the design object of Low Drift Temperature, the present invention focus on to optimize the precise rectification circuit design in agc circuit,
AGC active leveling circuit is improved, uses reversely by the lower high-speed diode device of leakage current, realizes very low temperature drift
Performance.Meanwhile Low Drift Temperature device is used in circuit, guarantee circuit temperature drift reduced levels.Such as resonant capacitance, operation are put
The type selecting of the core devices such as big device, filtering capacitance-resistance, proportion resistor.
The preposition conditioning device of the current vortex sensor of the Low Drift Temperature of the embodiment of the present invention, realizes extremely low temperature drift, in high-gain
Lower output is reliable and stable, improves current vortex front end circuit performance, is suitable for nanoscale precision measure application.
The additional aspect of the present invention and advantage will be set forth in part in the description, and will partially become from the following description
Obviously, or practice through the invention is recognized.
Detailed description of the invention
Above-mentioned and/or additional aspect of the invention and advantage will become from the description of the embodiment in conjunction with the following figures
Obviously and it is readily appreciated that, in which:
Fig. 1 is the schematic diagram of the current vortex of the prior art；
Fig. 2 is the schematic diagram of the LC antiresonant circuit of the prior art；
Fig. 3 is the structure chart according to the preposition conditioning device of current vortex sensor of the Low Drift Temperature of the embodiment of the present invention；
Fig. 4 is the circuit diagram according to the automatic gain controller of the embodiment of the present invention；
Fig. 5 is the circuit diagram according to the precise rectification circuit of the embodiment of the present invention；
Fig. 6 is the circuit diagram according to the buffer of the embodiment of the present invention；
Fig. 7 is the circuit diagram according to the signal amplification circuit of the embodiment of the present invention.
Specific embodiment
The embodiment of the present invention is described below in detail, examples of the embodiments are shown in the accompanying drawings, wherein from beginning to end
Same or similar label indicates same or similar element or element with the same or similar functions.Below with reference to attached
The embodiment of figure description is exemplary, it is intended to is used to explain the present invention, and is not considered as limiting the invention.
Preposition conditioning device, as fore-lying device refer to that the circuit being placed between information source or probe and data collector or electronics are set
It is standby, it is to aim to receive the weak voltage signals from information source and design.The embodiment of the present invention provides a kind of current vortex of Low Drift Temperature
Leading sensor conditioning device, be for eddy current probe driving source generate, the circuit of Detection of Weak Signals and conditioning.
As shown in figure 3, the preposition conditioning device of the current vortex sensor of the Low Drift Temperature of the embodiment of the present invention, comprising: sine wave
Signal source generative circuit 1, automatic gain controller 2, detection circuit, precise rectification circuit 3 and signal amplification circuit 4.It needs
Bright, automatic gain controller 2, detection circuit, precise rectification circuit 3 and signal amplification circuit 4 are all made of Low Drift Temperature device
It realizes.
Specifically, the output end of sine signal source generative circuit is connect with the input terminal of automatic gain controller 2, for giving birth to
At circuit output sine wave exciting signal to automatic gain controller 2.
In one embodiment of the invention, sine wave source generative circuit 1 uses Direct Digital Frequency Synthesizers DDS
Or the sine signal source of other frequency stabilizations.Frequency, the stability of amplitude of sine wave exciting signal directly determine entirely to sense
The stability of device output signal.When sine wave source generative circuit 1 is using DDS signal source, amplitude 1000Vpp, biasing
500mV.DDS signal source frequency stablize, can online programming change frequency, high resolution reach 0.029Hz, connect 50MHz crystal oscillator when,
Actual measurement can the exportable 5MHz of highest high-quality sine wave exciting signal.
The output end of automatic gain controller 2 (Automatic Generation Control) and one end of detection circuit
Connection exports sine-wave excitation for carrying out amplitude control to the sine wave exciting signal from sine signal source generative circuit
Signal is to detection circuit.
Specifically, as shown in figure 4, automatic gain controller 2 include: variable gain amplifier chip, passive filter circuit,
Built-in precise rectification circuit and instrument amplifier may be implemented to carry out feedback control to the signal amplitude of sine wave exciting signal.
Variable gain amplifier chip is for amplifying sine wave exciting signal.
The input terminal of built-in precise rectification circuit is connect with the output end of variable gain amplifier chip, for obtaining sine
Then the amplitude of wave excitation signal obtains the voltage output signal directly proportional to signal amplitude by passive filter circuit.
The input terminal of instrument amplifier is connect with passive filter circuit, for carrying out to voltage output signal and reference voltage
Compare, and comparison result is fed back to the input terminal of variable gain amplifier, output signal is adjusted by variable gain amplifier
Amplitude is steady state value.
With reference to Fig. 4, variable gain amplifier chip U10, passive filter circuit is made of R16, C19, L5, C17, to fixed ampllitude
Sinusoidal excitation signal after variable gain amplifier chip U10 amplification, by precise rectification circuit 3 and filter circuit U9,
The voltage output signal directly proportional to signal amplitude is obtained, is compared by instrument amplifier U6 with reference voltage Vref _ 1,
The G+ pin of variable gain amplifier chip U10 is fed back to, the method multiple of variable gain amplifier chip U10 is regulated and controled:
When the sinusoidal excitation signal of fixed ampllitude becomes larger, the voltage of precision rectifying and filtering output becomes larger, instrument amplifier
By the voltage compared with preset voltage after, reduce variable gain amplifier chip U10 G+ gain control pin voltage value,
The gain of U10 reduces, and reduces final output；Conversely, when the sinusoidal excitation signal of fixed ampllitude becomes smaller, precision rectifying and filter
Wave output voltage become smaller, instrument amplifier U6 by the voltage with preset voltage compared with after, increase variable gain amplifier chip
The gain of the voltage value of the G+ gain control pin of U10, U10 increases, and increases final output.Above-mentioned negative feedback process, can be with
So that the amplitude of output signal is steady state value.
It should be noted that influencing two factors of the circuit stability are as follows:
1, the stability of reference voltage Vref _ 1, reference voltage use Low Drift Temperature device ADR06 a reference source, and temperature drift parameter is small
In 10ppm, have good stability；
2, the stability of precision rectifying and filter circuit U9, the stability of precise rectification circuit 3, which becomes, determines automatic gain
The main reason for controller 2AGC output stability.
Built-in precise rectification circuit is described in detail below.Elder generation is needed, it is noted that precise rectification circuit 3 is to instigate
The operation conditioning circuit built with amplifier or discrete device, there are many kinds of classes, complete the rectification to AC signal, especially suitable for
The high-precision rectification of small signal is handled.
There are two precise rectification circuits 3 in the present invention, one is built-in precise rectification circuit, built-in and automatic gain control
In device 2 processed；Another precise rectification circuit 3, between probe coil and signal amplification circuit 4.The two precision rectifyings electricity
The structure on road 3 is close, equally uses the cores such as the operational amplifier of Low Drift Temperature, the high speed diode of low reversed cut-off leakage current
Device has extremely low temperature drift.
Built-in precise rectification circuit includes: the first operational amplifier, the first rectifier diode and the second rectifier diode, fortune
The negative input for calculating amplifier connects the output end of variable gain amplifier, and the positive input of the first operational amplifier is grounded,
The forward end of output the second rectifier diode of termination of first operational amplifier, the negative sense of the second rectifier diode terminate passive filter
Wave circuit connects the first rectifier diode on feedback network between the negative input and output end of the first operational amplifier,
Wherein, the first operational amplifier uses Low Drift Temperature operational amplifier.
First operational amplifier open-loop gain of built-in precise rectification circuit, use is high, and circuit is the first rectification second level
Pipe D8, the second rectifier diode D9 are placed in the feedback control loop of amplifier composition, largely reduced diode forward conduction voltage drop
Bring distortion, improves circuit precision.But in diode cut-off, because all there is reversed cut-off electric leakage in practical diode component
Stream, due to semiconductor diode self-characteristic, the reversed cut-off leakage current and temperature have very strong correlation, work as temperature change
When, precision rectifying amplitude output signal corresponding change introduces temperature drift errors.The present invention selects reversely lower by leakage current
High-speed diode device.
It should be noted that these unlimited above-mentioned models of high-speed diode device that the present invention uses, reversed with uA grades
The high speed diode of cut-off leakage current is applied to the agc circuit and precise rectification circuit 3 of the preposition conditioning circuit of current vortex, belongs to
The type selecting range that the present invention is protected, details are not described herein.
Based on this, the present invention is realized by automatic gain controller 2 carries out amplitude control, output to sine wave exciting signal
The sine wave exciting signal of positive negative bipolar, constant amplitude.The present invention influences the main reason for output is stablized to agc circuit and carries out
Solution is analyzed and proposed, keeps its output stability good.
Detection circuit includes: divider resistance 5, probe coil 6, compensating electric capacity array 7, wherein the other end of divider resistance 5
It being connect with one end of probe coil, the other end ground connection of probe coil 6, compensating electric capacity array 7 is connected in parallel with probe coil 6,
The sine wave exciting signal from automatic gain controller 2 is received respectively, and probe coil 6 is in parallel with compensating electric capacity array 7 to be occurred
Resonance, after eddy current effect occurs for probe coil 6, the voltage at 6 both ends of probe coil generates variation, the voltage output to precision
Rectification circuit 3.
The input terminal of precise rectification circuit 3 is connect with detection circuit, for the voltage for carrying out self-detection circuit received
It is rectified, obtains the direct current amplitude of probe both ends small-signal, generate direct current signal.
Specifically, as shown in figure 5, precise rectification circuit 3 includes: second operational amplifier, third rectifier diode and
Four rectifier diodes, the positive input of second operational amplifier meet compensating electric capacity array (C52, C32, C33).Wherein, according to
Actual conditions, 1~3 Low Drift Temperature capacitor of Matching installation, Low Drift Temperature capacitor belongs to present invention protection as frequency compensation and wants herein
Point.
The negative input of second operational amplifier is grounded, second operational amplifier negative input and output end it
Between third rectifier diode D10 and the 4th rectifier diode D11 is connected on feedback network, precise rectification circuit 3 is to search coil
The signal sinusoidal excitation signal at both ends is rectified, and positive half-wave unipolar signal is obtained, and is shaped as directly by passive filtering network
Flow signal.Wherein, second operational amplifier uses Low Drift Temperature operational amplifier.The rectification of third rectifier diode D10 and the 4th two
Pole pipe D11 uses the high speed diode of low reverse current leakage.It should be noted that the high-speed diode device that the present invention uses is not
These above-mentioned models are limited, the high speed diode with uA grades of reversed cut-off leakage currents is applied to the preposition conditioning circuit of current vortex
Agc circuit and precise rectification circuit 3 belong to the type selecting range that the present invention is protected, and details are not described herein.
In addition, the filter circuit that precise rectification circuit 3 includes, uses the lower capacitor of temperature coefficient herein, to guarantee to filter
Wave circuit does not introduce amplitude variation error.
In one embodiment of the invention, as shown in fig. 6, between precise rectification circuit 3 and signal amplification circuit 4 into
One step is provided with buffer, and buffer uses Low Drift Temperature operational amplifier, and the input of buffer connects the output of precise rectification circuit 3
End, the input terminal of the input termination signal amplification circuit 4 of buffer.That is, being done using Low Drift Temperature amplifier slow before amplifying
Rush device, influence of the isolating amplifier circuit input impedance to precise rectification circuit 3 and filter circuit.
The input terminal of signal amplification circuit 4 is connect with the output end of precise rectification circuit 3, for believing the direct current received
Number processing is amplified, exports the probe that amplified analog signal is coupled to current vortex sensor.
Specifically, as shown in fig. 7, signal amplification circuit 4 includes: third operational amplifier, feedback resistance and toggle switch,
Wherein, each access of toggle switch and a feedback resistance are connected in series, and gate corresponding feedback resistance by toggle switch,
Dial-up and feedback resistance are set on the feedback network between the negative input and output end of third operational amplifier, wherein the
Three operational amplifiers use Low Drift Temperature operational amplifier, and feedback resistance floats resistance device, feedback resistance R28 using High Precision Low Temperature
Resistance value be 20K, after can gating feedback resistance by toggle switch S1, circuit gain is 50 times, similarly, it is anti-can to gate other
Feed resistance, realizes other gains.
By the optimization and the type selecting of various core devices to foregoing circuit, before the current vortex sensor for designing Low Drift Temperature
Conditioning circuit is set, is tested by many experiments, when using 50 times of high-gains, using air-heater simulation ambient temperature variation, variation
For range up to 60 degrees Celsius, it is excellent to demonstrate circuit designed by the present invention by current vortex sensor overall output drift 100mV or so
Low Drift Temperature characteristic.
The preposition conditioning device of the current vortex sensor of Low Drift Temperature according to an embodiment of the present invention believes the sinusoidal excitation of generation
It number is applied in the detection circuit that divider resistance, probe coil and compensating electric capacity array are constituted, probe coil and compensating electric capacity are simultaneously
Resonance occurs for connection, and pumping signal is undertaken together with divider resistance, after eddy current effect occurs for probe coil, coil both ends
Voltage generates faint variation, which is positive and negative bipolar voltage, rectifies to obtain positive half-wave unipolarity letter by precise rectification circuit
Number, it is shaped as direct current signal by passive filtering network, output is then amplified by the operational amplification circuit of fixed gain, transfers to it
His acquisition system acquisition process.
In order to realize that the design object of Low Drift Temperature, the present invention focus on to optimize the precise rectification circuit design in agc circuit,
AGC active leveling circuit is improved, uses reversely by the lower high-speed diode device of leakage current, realizes very low temperature drift
Performance.Meanwhile Low Drift Temperature device is used in circuit, guarantee circuit temperature drift reduced levels.Such as resonant capacitance, operation are put
The type selecting of the core devices such as big device, filtering capacitance-resistance, proportion resistor.
The preposition conditioning device of the current vortex sensor of the Low Drift Temperature of the embodiment of the present invention, realizes extremely low temperature drift, in high-gain
Lower output is reliable and stable, improves current vortex front end circuit performance, is suitable for nanoscale precision measure application.
In the description of this specification, reference term " one embodiment ", " some embodiments ", " example ", " specifically show
The description of example " or " some examples " etc. means specific features, structure, material or spy described in conjunction with this embodiment or example
Point is included at least one embodiment or example of the invention.In the present specification, schematic expression of the above terms are not
Centainly refer to identical embodiment or example.Moreover, particular features, structures, materials, or characteristics described can be any
One or more embodiment or examples in can be combined in any suitable manner.
Although the embodiments of the present invention has been shown and described above, it is to be understood that above-described embodiment is example
Property, it is not considered as limiting the invention, those skilled in the art are not departing from the principle of the present invention and objective
In the case where can make changes, modifications, alterations, and variations to the above described embodiments within the scope of the invention.The scope of the present invention
By appended claims and its equivalent limit.
Claims (7)
1. a kind of preposition conditioning device of the current vortex sensor of Low Drift Temperature characterized by comprising sine wave source generates electricity
Road, automatic gain controller, detection circuit, precise rectification circuit and signal amplification circuit, wherein
The output end of the sine signal source generative circuit is connect with the input terminal of the automatic gain controller, for generating electricity
Road exports sine wave exciting signal to the automatic gain controller；
The output end of the automatic gain controller is connect with one end of the detection circuit, for from the sinusoidal signal
The sine wave exciting signal of source generative circuit carries out amplitude control, output sine wave exciting signal to the detection circuit；
The detection circuit includes: divider resistance, probe coil, compensating electric capacity array, wherein the divider resistance it is another
One end is connect with one end of the probe coil, the other end of probe coil ground connection, the compensating electric capacity array with it is described
Probe coil is connected in parallel, and receives the sine wave exciting signal from the automatic gain controller, the probe coil respectively
Resonance occurs with compensating electric capacity array in parallel, after eddy current effect occurs for the probe coil, the probe coil both ends
Voltage generates variation, the voltage output to the precise rectification circuit；
The input terminal of the precise rectification circuit is connect with the detection circuit, for coming from the detection circuit to what is received
Voltage rectified, generate direct current signal；
The input terminal of the signal amplification circuit is connect with the output end of the precise rectification circuit, for the direct current received
Signal amplifies processing, exports the probe that amplified analog signal is coupled to current vortex sensor,
Wherein, the sine wave source generative circuit, automatic gain controller, detection circuit, precise rectification circuit and signal
Amplifying circuit is all made of the realization of Low Drift Temperature device.
2. the preposition conditioning device of the current vortex sensor of Low Drift Temperature as described in claim 1, which is characterized in that the sine wave
Signal source generative circuit uses Direct Digital Frequency Synthesizers DDS.
3. the preposition conditioning device of the current vortex sensor of Low Drift Temperature as described in claim 1, which is characterized in that the automatic increasing
Beneficial controller includes: variable gain amplifier chip, passive filter circuit, built-in precise rectification circuit and instrument amplifier,
In,
The variable gain amplifier chip is for amplifying sine wave exciting signal；
The input terminal of the built-in precise rectification circuit is connect with the output end of the variable gain amplifier chip, for obtaining
Then it is defeated to obtain the voltage directly proportional to signal amplitude by the passive filter circuit for the amplitude of the sine wave exciting signal
Signal out；
The input terminal of the instrument amplifier is connect with the passive filter circuit, for the voltage output signal and reference
Voltage is compared, and comparison result is fed back to the input terminal of the variable gain amplifier, is amplified by the variable gain
The amplitude that device adjusts output signal is steady state value.
4. the preposition conditioning device of the current vortex sensor of Low Drift Temperature as claimed in claim 3, which is characterized in that the built-in essence
Close rectification circuit includes: the first operational amplifier, the first rectifier diode and the second rectifier diode, the operational amplifier
Negative input meets the output end of the variable gain amplifier, the positive input ground connection of first operational amplifier, institute
The output for stating the first operational amplifier terminates the forward end of second rectifier diode, the negative sense of second rectifier diode
The passive filter circuit is terminated, is connected on feedback network between the negative input and output end of first operational amplifier
Connect first rectifier diode, wherein first operational amplifier uses Low Drift Temperature operational amplifier.
5. the preposition conditioning device of the current vortex sensor of Low Drift Temperature as described in claim 1, which is characterized in that the precision is whole
Current circuit includes: second operational amplifier, third rectifier diode and the 4th rectifier diode, the second operational amplifier
Positive input connects the compensating electric capacity array, the negative input ground connection of the second operational amplifier, described second
The third rectifier diode and the 4th rectification are connected between the negative input and output end of operational amplifier on feedback network
Diode, precise rectification circuit sinusoidal excitation signal described in the signal at search coil both ends rectify, and obtain just half
Wave unipolar signal is shaped as direct current signal by passive filtering network, wherein
The second operational amplifier uses Low Drift Temperature operational amplifier.
6. the preposition conditioning device of the current vortex sensor of Low Drift Temperature as described in claim 1, which is characterized in that in the precision
Buffer is further provided between rectification circuit and the signal amplification circuit, the buffer uses Low Drift Temperature operation amplifier
Device, the input of the buffer connect the output end of the precise rectification circuit, and the input of the buffer terminates the signal and puts
The input terminal of big circuit.
7. the preposition conditioning device of the current vortex sensor of Low Drift Temperature as described in claim 1, which is characterized in that the signal is put
Big circuit includes: third operational amplifier, feedback resistance and toggle switch, wherein each access of the toggle switch and one
A feedback resistance is connected in series, and gates corresponding feedback resistance, the dial-up and the feedback by the toggle switch
Resistance is set on the feedback network between the negative input and output end of the third operational amplifier, wherein the third
Operational amplifier uses Low Drift Temperature operational amplifier, and the feedback resistance floats resistance device using High Precision Low Temperature.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910427333.5A CN110260773B (en) | 2019-05-22 | Low-temperature-drift front-end conditioning device of eddy current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910427333.5A CN110260773B (en) | 2019-05-22 | Low-temperature-drift front-end conditioning device of eddy current sensor |
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| CN110260773A true CN110260773A (en) | 2019-09-20 |
| CN110260773B CN110260773B (en) | 2024-07-05 |
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| CN114147622A (en) * | 2021-12-10 | 2022-03-08 | 北京烁科精微电子装备有限公司 | CMP eddy current terminal point detection device |
| CN114252146A (en) * | 2021-12-10 | 2022-03-29 | 中国计量科学研究院 | Sensitivity frequency characteristic adjusting circuit, vibration sensor, and sensor |
| CN114577105A (en) * | 2022-04-01 | 2022-06-03 | 南京航空航天大学 | Motor displacement sensor based on eddy current principle |
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| CN114577105A (en) * | 2022-04-01 | 2022-06-03 | 南京航空航天大学 | Motor displacement sensor based on eddy current principle |
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