CN109030906A - A kind of current probe - Google Patents
A kind of current probe Download PDFInfo
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- CN109030906A CN109030906A CN201710431464.1A CN201710431464A CN109030906A CN 109030906 A CN109030906 A CN 109030906A CN 201710431464 A CN201710431464 A CN 201710431464A CN 109030906 A CN109030906 A CN 109030906A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
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Abstract
The present invention provides a kind of current probes, are related to current measurement techniques field.Hall sensor is embedded in one side of lower magnetic core, and passes through in the magnetic head of lower magnetic core and upper magnetic core composition and have measured wire；Two output ends of Hall sensor are separately connected differential amplifier circuit non-inverting input terminal and inverting input terminal；The output end of differential amplifier circuit is connected to the inverting input terminal of operation amplifier circuit；Feedback system circuit connection is between the inverting input terminal and output end of operation amplifier circuit；The opposite side on one side that lower magnetic core is wound with measured wire is wound with secondary winding coil, the output end of one end connection operation amplifier circuit of secondary winding coil, and the other end of secondary winding coil connects one end and the signal output apparatus of the first parallel end connection resistance；The other end of first parallel end connection resistance is grounded.Two output ends of Hall sensor are separately connected differential amplifier circuit non-inverting input terminal and inverting input terminal, the output of Hall sensor may make to balance.
Description
Technical field
The present invention relates to current measurement techniques field more particularly to a kind of current probes.
Background technique
Currently, with the development of electronic technology, the application of current probe is very extensive.The basic principle of current probe
It is to flow through the electric current of conducting wire to generate magnetic field around its conducting wire, magnetic field is received by sensor, converts linear electricity
Pressure amount.The linear voltage amount can be shown and be measured on oscillograph or other measuring instruments, to reach in conducting wire
The purpose that measures of electric current.It can be widely applied to survey by way of carrying out current in wire measurement current probe at present
Measure motor driving, Switching Power Supply, power inverter/converter, LCD display (Liquid Crystal Display, liquid crystal
Show device), electric ballast, the stable state of amplifier or transient current, transportation system, mobile communication, industry/consumer electronics produce
Product and semiconductor equipment etc..
The simple principle block diagram of the current probe of the prior art is as shown in Figure 1.The current probe of the prior art, which uses, to be become
Depressor principle and Hall effect principle can be measured by the current probe down toward DC (direct current, Direct Current)
Low-frequency current signal, and up to high-frequency current signal.The current probe forms closure by upper magnetic core 101 and lower magnetic core 102
Magnetic core 103.The current probe further includes the Hall sensor 105 being clipped on lower 102 section of magnetic core, additionally includes signal amplification
Device 106, single-pole double-throw switch (SPDT) 112, power amplifier 111, feedback system 103, the coil 107 being wound on lower magnetic core 103, termination
Resistance 109 and signal output stage operational amplifier 108.105 1 biased electricals of Hall sensor are given by system power supply 110
Pressure, to add magnetic flux to 105 sensing part of Hall sensor, Hall sensor 105 is exportable linearly related with it
Hall voltage parameter.Signal amplifier 106 acquires the Hall voltage parameter that Hall sensor 105 exports.And pass through single-pole double throw
The signal that signal amplifier 106 exports is coupled in power amplifier 111 by switch 112, the magnetic head demagnetization signal of current probe
And be coupled in power amplifier 111 by single-pole double-throw switch (SPDT) 112, it is passed after being amplified signal by power amplifier 111
It is defeated to arrive coil 107, the secondary windings for the transformer that coil 107 is formed as closed magnetic core 103, and armature winding is exactly tested leads
Line 104.Another termination terminating resistor 109 of coil 107, while output stage operational amplifier 108 is connect, as output stage.Due to
104 surrounding of measured conductor can generate magnetic field, and magnetic flux can be strapped in magnetic core by the closed magnetic core 103 of high magnetic permeability.When magnetic flux hangs down
When direct puncture crosses the Hall sensor 105 being embedded in magnetic core, Hall sensor 105 can export Hall voltage parameter, Hall electricity
Pressure parameter is inputed to signal amplifier 106 in the form of difference, then is communicated to power amplifier by single-pole double-throw switch (SPDT) 112
111.The switch 112 of single-pole double throw also can choose demagnetization signal and be input to power amplifier 111.Feedback system 113 is generally adopted
It is fed back with conventional, electric-resistance, to achieve the purpose that adjust gain stabilization system.Power amplifier 111 linearly puts Hall voltage parameter
The greatly magnitude of current, secondary coil of the driving coil 107 as transformer.The flow direction and be tested that the electric current generates in coil
Flow direction that conducting wire generates in coil is contrary on the contrary, both magnetic fluxs are equal in magnitude in magnetic core, cancels out each other,
The electric current that the electric current in measured conductor and power amplifier 111 export at this time has certain linear relationship, power amplifier 111
The magnitude of current of output is output in oscillograph or measuring instrument by output stage operational amplifier 108.It is put by measuring power
The electric current that big device 111 exports measures the electric current flowed through in measured wire, is exactly the principle of current probe Zero flux measurement.
During carrying out the above-mentioned prior art, inventor is had found during Reusability current probe, closure
The magnetic head of magnetic core 103 is easy to produce remanent magnetism, this will introduce additional error to the measurement of current probe, so that measurement result produces
Raw deviation.For a user in order to make above-mentioned current probe carry out demagnetization, need to proceed as follows, it is necessary first to by current-carrying
Conductor 104 is shifted out from the closure magnetic head 103 of current probe, and then current probe circuit passes through control single-pole double-throw switch (SPDT)
112, the signal that will enter into power amplifier 111 switches to demagnetization signal, carries out demagnetization to closed magnetic core 103.Therefore, hilted broadsword
In this process, will seem commutator 112 key especially.Due to the frequent switching of single-pole double-throw switch (SPDT) 112, it is easy
It damages, to affect the demagnetization performance to closed magnetic core 103.In addition, due to the bias voltage of Hall sensor 105 itself
Asymmetry, can also have signal output in the case where no measured conductor.It is so also to bring one to current probe measurement
A DC offset error.The prior art is to handle the DC offset error by adjusting the bias voltage of Hall sensor to realize
's.However this bearing calibration sensitivity requirement is higher, the phenomenon that being easy to appear repeatedly in adjustment process, always zero point or so very
Hardly possible, which is adjusted, arrives zero point.As it can be seen that the current probe of the prior art haves the defects that in structure, it be easy to cause the measurement of current probe not
Accurate problem.
Summary of the invention
The embodiment of the present invention provides a kind of current probe, and to solve the current probe of the prior art, there are lacking in structure
It falls into, be easy to cause the problem of the measurement inaccuracy of current probe.
In order to achieve the above objectives, the present invention adopts the following technical scheme:
A kind of current probe, including be made of upper magnetic core and lower magnetic core closed magnetic core, Hall sensor, difference amplifier
Circuit, operation amplifier circuit, feedback system circuit, the first parallel end connection resistance and signal output apparatus；
The Hall sensor is embedded in one side of the lower magnetic core, and wears in the magnetic head of the lower magnetic core and upper magnetic core composition
Measured wire is crossed；Two output ends of the Hall sensor are separately connected differential amplifier circuit non-inverting input terminal and reverse phase
Input terminal；The output end of the differential amplifier circuit is connected to the inverting input terminal of the operation amplifier circuit；It is described anti-
Feedback system circuit connection is between the inverting input terminal and output end of the operation amplifier circuit；The lower magnetic core is wound with tested
The opposite side on one side of conducting wire is wound with secondary winding coil, and one end of the secondary winding coil connects the operation amplifier circuit
Output end, the other end of the secondary winding coil connect the first parallel end connection resistance one end and signal output electricity
Road；The other end of the first parallel end connection resistance is grounded.
Further, the current probe further includes power amplifier circuit and direct current calibration signal generation circuit；It is described
The inverting input terminal of power amplifier circuit is connect with the output end of the operation amplifier circuit, the power amplifier circuit
Output end connect with one end of the secondary winding coil；The direct current calibration signal generation circuit and the power amplifier
The non-inverting input terminal of circuit or the non-inverting input terminal connection of operation amplifier circuit.
Further, the current probe further includes demagnetization signal generating circuit；The demagnetization signal generating circuit and institute
State the non-inverting input terminal of power amplifier circuit or the non-inverting input terminal connection of operation amplifier circuit.
Specifically, the signal output apparatus includes an output stage operation amplifier circuit；The secondary winding coil
The other end connects one end of the first parallel end connection resistance and the input terminal of the output stage operation amplifier circuit；It is described defeated
Measurement output end of the output end of grade operation amplifier circuit as the current probe out.
Specifically, the Hall sensor has first input end, the second input terminal, the first output end and the second output
End；The power supply output end of the first input end and the second input terminal connection system power supply circuit；
First output end connects the non-inverting input terminal of the differential amplifier circuit, and the second output terminal connects institute
State the inverting input terminal of differential amplifier circuit；The output end of the differential amplifier circuit and the operation amplifier circuit
RC filter circuit is additionally provided between inverting input terminal；The output end of the differential amplifier circuit connects the defeated of RC filter circuit
Enter end, the inverting input terminal of the output end connection operation amplifier circuit of RC filter circuit.
Specifically, the signal output apparatus includes series termination resistance, transmission cable, filter circuit, the second parallel connection
Terminating resistor and high frequency connectors；
One end of the series termination resistance is connect with the other end of the secondary winding coil；The series termination resistance
The other end be sequentially connected the transmission cable, filter circuit and high frequency connectors；The filter circuit and the high frequency
The junction of connector connects one end of the second parallel end connection resistance, another termination of the second parallel end connection resistance
Ground；The high frequency connectors with the AFE(analog front end) of oscillograph for connecting.
Specifically, the differential amplifier circuit includes a difference amplifier chip；The difference amplifier chip includes
Inverting input terminal IN-, non-inverting input terminal IN+, first resistor connecting pin Rg1, second resistance connecting pin Rg2, positive pole connection
Hold Vs+, power cathode connecting pin Vs ﹣, output end vo ut and reference voltage connecting pin REF；
First output end of the Hall sensor connects the inverting input terminal IN ﹣；The second of the Hall sensor
Output end connects the non-inverting input terminal IN+；
The first resistor connecting pin Rg1 is connected with second resistance connecting pin Rg2 by a first resistor；
The positive pole connecting pin Vs+ is loaded with positive 12 volts of voltage；The power cathode connecting pin Vs ﹣ is loaded with minus 12
Lie prostrate voltage；
The reference voltage connecting pin REF ground connection；
The output end vo ut connects the input terminal of the RC filter circuit.
Specifically, the feedback system circuit includes a digital adjustable potentiometer；The number adjustable potentiometer includes the
One pin connecting pin A1, second pin connecting pin A2, third pin connecting pin B1, the 4th pin connecting pin B2, the 5th pin connect
End W1, the 6th pin connecting pin W2, ground terminal GND, operating voltage connecting pin VDD, bi-directional data connection line end SDA are met with timely
Clock connects line end SCL；
The ground terminal GND ground connection；The operating voltage connecting pin VDD is loaded with positive 5 volts of voltage；The bi-directional data connects
Terminals SDA is loaded with bi-direction data signal；The clock connection line end SCL is loaded with clock signal；First pin connects
End A1 and the 5th pin connecting pin W1 is met to be connected；Positive 12 are loaded with after one second resistance of second pin connecting pin A2 connection
Lie prostrate voltage；Minus 12 volts of voltage is loaded with after 4th pin connecting pin B2 connection, one 3rd resistor.
Specifically, the operation amplifier circuit include: operational amplifier, the 4th resistance, the 5th resistance, the 6th resistance with
And first capacitor；
The operational amplifier is loaded with positive 12V voltage and negative 12V voltage；The inverting input terminal of the operational amplifier is logical
The 4th resistance is crossed to connect with the output end of the RC filter circuit；The non-inverting input terminal of the operational amplifier is separately connected
One end of 5th resistance and one end of the 6th resistance；The other end of 5th resistance is as the operation amplifier circuit
Non-inverting input terminal；The other end of 6th resistance is grounded；The output end of the operational amplifier and operational amplifier it is anti-
Phase input terminal connects the both ends of the first capacitor；The output end of the operational amplifier is also connected with the digital adjustable potentiometer
Third pin connecting pin B1；What the inverting input terminal of the operational amplifier was also connected with the digital adjustable potentiometer first draws
Foot connecting pin A1.
Specifically, the power amplifier circuit include: power amplifier, the 7th resistance, the 8th resistance, the 9th resistance with
And the tenth resistance；
The power amplifier is loaded with positive 12V voltage and negative 12V voltage；The inverting input terminal of the power amplifier is logical
The 8th resistance is crossed to connect with the output end of the operational amplifier；The non-inverting input terminal of the power amplifier is separately connected
One end of 9th resistance and one end of the tenth resistance；The other end of 9th resistance is as the power amplifier circuit
Non-inverting input terminal；The other end of tenth resistance is grounded；The output end of the power amplifier and power amplifier it is anti-
Phase input terminal connects the both ends of the 7th resistance；The output end of the power amplifier is also connected with the secondary winding coil
One end.
Specifically, the direct current calibration signal generation circuit includes: direct current calibration operational amplifier, eleventh resistor, the
12 resistance and the second capacitor；
The direct current calibration operational amplifier is loaded with positive 12V voltage and negative 12V voltage；The direct current calibrates operation amplifier
The inverting input terminal of device is connect by the eleventh resistor with the 6th pin connecting pin W2 of the digital adjustable potentiometer；Institute
The non-inverting input terminal for stating direct current calibration operational amplifier calibrates operational amplifier by the twelfth resistor and the direct current
Output end connection；The output end of the direct current calibration operational amplifier also passes through second capacity earth；The direct current calibration
Output end of the output end of operational amplifier as the direct current calibration signal generation circuit.
Specifically, the demagnetization signal generating circuit include: demagnetization operational amplifier, thirteenth resistor, the 14th resistance,
15th resistance, the 16th resistance, third capacitor, the 4th capacitor and the 5th capacitor；
The demagnetization operational amplifier is loaded with positive 12V voltage and negative 12V voltage；The reverse phase of the demagnetization operational amplifier
Input terminal passes through the 14th resistance eutral grounding；The non-inverting input terminal of the demagnetization operational amplifier passes through the 4th capacitor and the tenth
It is grounded after the parallel circuit of five resistance composition；The non-inverting input terminal of the demagnetization operational amplifier also pass through the 5th capacitor and
The output end of the demagnetization operational amplifier is connected after the series circuit of 16th resistance composition；The demagnetization operational amplifier
Output end is loaded with degaussing control signal；The output end of the demagnetization operational amplifier also passes through the third capacitor and the 13rd
It is grounded after the parallel circuit of resistance composition；The output end of the demagnetization operational amplifier is as the demagnetization signal generating circuit
Output end.
A kind of current probe provided in an embodiment of the present invention, by the way that two output ends of Hall sensor are separately connected difference
Divide amplifier circuit non-inverting input terminal and inverting input terminal, and not one end ground connection of Hall sensor, the other end connect difference
Amplifier circuit avoids asymmetry of the hall device due to bias voltage itself so that the output of Hall sensor balances, and is not having
There is signal output to cause the problem of the measurement result inaccuracy of current probe in the case where having measured conductor.
Detailed description of the invention
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below
There is attached drawing needed in technical description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this
Some embodiments of invention without any creative labor, may be used also for those of ordinary skill in the art
To obtain other drawings based on these drawings.
Fig. 1 is the simple principle schematic diagram of the current probe of the prior art；
Fig. 2 is a kind of structural schematic diagram one of current probe provided in an embodiment of the present invention；
Fig. 3 is a kind of structural schematic diagram two of current probe provided in an embodiment of the present invention；
Fig. 4 is a kind of structural schematic diagram three of current probe provided in an embodiment of the present invention；
Fig. 5 is the structural schematic diagram of the system power supply circuit in the embodiment of the present invention；
Fig. 6 is the schematic diagram of the Hall sensor in the embodiment of the present invention；
Fig. 7 is a kind of structural schematic diagram four of current probe provided in an embodiment of the present invention；
Fig. 8 is the schematic diagram of the differential amplifier circuit in the embodiment of the present invention；
Fig. 9 is the schematic diagram of the feedback system circuit in the embodiment of the present invention；
Figure 10 is the schematic diagram of the operation amplifier circuit in the embodiment of the present invention；
Figure 11 is the schematic diagram of the power amplifier circuit in the embodiment of the present invention；
Figure 12 is the schematic diagram of the direct current calibration signal generation circuit in the embodiment of the present invention；
Figure 13 is the schematic diagram of the demagnetization signal generating circuit in the embodiment of the present invention；
Figure 14 is the schematic diagram of the Butterworth filter circuit in the embodiment of the present invention；
Figure 15 is the schematic diagram of the output impedance match circuit in the embodiment of the present invention；
Figure 16 is the schematic diagram of the high frequency output terminal BNC in the embodiment of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
As shown in Fig. 2, the embodiment of the present invention provides a kind of current probe 20, including by 202 groups of upper magnetic core 201 and lower magnetic core
At closed magnetic core 203, Hall sensor 204, differential amplifier circuit 220, operation amplifier circuit 205, feedback system electricity
Road 207 (being used for gain adjustment), the first parallel end connection resistance 211 and signal output apparatus 212.
The Hall sensor 204 is embedded in one side of the lower magnetic core 202, and the lower magnetic core 202 and 201 groups of upper magnetic core
At magnetic head in pass through have measured wire 213.Two output ends of the Hall sensor 204 are separately connected difference amplifier electricity
The non-inverting input terminal and inverting input terminal on road 220；The output end of the differential amplifier circuit 220 is connected to operational amplifier electricity
The inverting input terminal on road 205；The feedback system circuit 207 is connected to the inverting input terminal of the operation amplifier circuit 205
Between output end；The opposite side on one side that the lower magnetic core 202 is wound with measured wire 213 is wound with secondary winding coil 214, described
One end of secondary winding coil 214 connects the output end of the operation amplifier circuit 205, the secondary winding coil 214
The other end connects one end and the signal output apparatus 212 of the first parallel end connection resistance 211；The first parallel end connection resistance
211 other end ground connection.
In addition, as shown in Fig. 2, the current probe 20, further includes system power supply circuit 210, the system power supply circuit 210
It powers for each section of entire current probe 20.
Further, as shown in figure 3, the current probe 20 further includes power amplifier circuit 206 and direct current calibration letter
Number generation circuit 209；The output of the inverting input terminal of the power amplifier circuit 206 and the operation amplifier circuit 205
End connection, the output end of the power amplifier circuit 206 are connect with one end of the secondary winding coil 214；The direct current
The non-inverting input terminal or operation amplifier circuit 205 of calibration signal generation circuit 209 and the power amplifier circuit 206
Non-inverting input terminal connection.
Further, as shown in figure 3, the current probe 20 further includes demagnetization signal generating circuit 208；The demagnetization letter
The non-inverting input terminal of number generation circuit 208 and the power amplifier circuit 206 or operation amplifier circuit 205 it is same mutually defeated
Enter end connection.In Fig. 3, only with a kind of connection side of demagnetization signal generating circuit 208 and direct current calibration signal generation circuit 209
It is illustrated for formula, details are not described herein again for other connection types.
Since closed magnetic core 203 is made of high frequency magnetic material, can be magnetized in magnetic field, the magnetic domain in closed magnetic core exists
Arrangement that will be orderly under the action of external magnetic field, therefore, closed magnetic core has magnetism.Magnetic domain is still orderly after magnetic field is removed
Arrangement, that is to say, that closed magnetic core still has magnetism.Closed magnetic core still maintains magnetic in the case where removing external magnetic field
Property, i.e. remanent magnetism.Therefore it needs to carry out demagnetization using demagnetization signal generating circuit 208.
In this way, measured signal and demagnetization signal are overlapped, so that the function of direct demagnetization is realized, in addition by tested letter
Number and direct current calibration signal be overlapped, so as to realize DC offset calibration.
Specifically, as shown in figure 4, the signal output apparatus 212 includes an output stage operation amplifier circuit 215；Institute
The other end for stating secondary winding coil 214 connects one end of the first parallel end connection resistance 211 and the output stage operation is put
The input terminal of big device circuit 215；Survey of the output end of the output stage operation amplifier circuit 215 as the current probe 20
Measure output end.
Specifically, the structure of the system power supply circuit 210 can be as shown in figure 5, system power supply circuit chip therein
Including empty foot NC1 to NC3, input pin IN, output pin OUT, grounding pin GND, Level tune controls pin NR and electricity
Pressure fine tuning pin TRIM；In addition the structure of system power supply circuit 210 further includes two amplifiers.
Specifically, as shown in fig. 6, the Hall sensor 204 has first input end 216, the second input terminal 217, the
One output end 218 and second output terminal 219；The first input end 216 and the second input terminal 217 connect system power supply circuit
210 power supply output end, i.e., the output end of two amplifiers as shown in Figure 5.
Further, as shown in fig. 7, the first output end 218 of the Hall sensor 204 can connect difference amplifier electricity
The second output terminal 219 of the non-inverting input terminal on road 220, the Hall sensor 204 can connect the differential amplifier circuit
220 inverting input terminal；The output end of the differential amplifier circuit 220 connects the input terminal of a RC filter circuit 221, RC filter
The inverting input terminal of the output end connection operation amplifier circuit 205 of wave circuit 221.
Specifically, as shown in fig. 7, the signal output apparatus 212 include series termination resistance 222, transmission cable 223,
Filter circuit 224, the second parallel end connection resistance 225 and high frequency connectors 226.
One end of the series termination resistance 222 is connect with the other end of the secondary winding coil 214；The series connection end
The other end of connecting resistance 222 is sequentially connected the transmission cable 223, filter circuit 224 and high frequency connectors 226；The filter
Wave device circuit 224 connect one end of the second parallel end connection resistance 225 with the junction of the high frequency connectors 226, described
The other end of second parallel end connection resistance 225 is grounded；The high frequency connectors 226 are for the AFE(analog front end) 301 with oscillograph 30
Connection.
Specifically, as shown in figure 8, the differential amplifier circuit 220 includes a difference amplifier chip 227；The difference
Dividing amplifier chip includes inverting input terminal IN-, non-inverting input terminal IN+, first resistor connecting pin Rg1, second resistance connecting pin
Rg2, positive pole connecting pin Vs+, power cathode connecting pin Vs ﹣, output end vo ut and reference voltage connecting pin REF.
The inverting input terminal IN ﹣ in 218 connection figure 8 of the first output end of Hall sensor 204 described in Fig. 6；
The non-inverting input terminal IN+ in 219 connection figure 8 of second output terminal of the Hall sensor 204.
As shown in figure 8, the first resistor connecting pin Rg1 and second resistance connecting pin Rg2 is connected by a first resistor 228
It connects.
The positive pole connecting pin Vs+ is loaded with positive 12 volts of voltage；The power cathode connecting pin Vs ﹣ is loaded with minus 12
Lie prostrate voltage.
The reference voltage connecting pin REF ground connection.
The output end vo ut of the difference amplifier chip 227 connects the input terminal of the RC filter circuit 221.
Herein, since the signal of Hall sensor output is very faint, and it is readily incorporated noise, noise will be led greatly very much
The measurement minimum precision of current probe is caused to become larger, probe performance is deteriorated.In order to reduce the noise of the part, therefore in differential amplification
One RC filter circuit is set after device, so as to inhibit noise well, improves signal-to-noise ratio, improves the property of current probe
Energy.
Specifically, as shown in figure 9, the feedback system circuit 207 includes a digital adjustable potentiometer 229；The number
Adjustable potentiometer 229 includes the first pin connecting pin A1, second pin connecting pin A2, third pin connecting pin B1, the 4th pin
Connecting pin B2, the 5th pin connecting pin W1, the 6th pin connecting pin W2, ground terminal GND, operating voltage connecting pin VDD, two-way number
Line end SCL is connected according to connection line end SDA and clock.
The ground terminal GND ground connection；The operating voltage connecting pin VDD is loaded with positive 5 volts of voltage；The bi-directional data connects
Terminals SDA is loaded with bi-direction data signal (SDA)；The clock connection line end SCL is loaded with clock signal (SCL)；It is described
First pin connecting pin A1 and the 5th pin connecting pin W1 are connected；One second resistance of second pin connecting pin A2 connection
Positive 12 volts of voltage is loaded with after 230；Minus 12 volts of electricity are loaded with after 4th pin connecting pin B2 connection, one 3rd resistor 231
Pressure.
Specifically, as shown in Figure 10, the operation amplifier circuit 205 includes: operational amplifier 232, the 4th resistance
233, the 5th resistance 234, the 6th resistance 235 and first capacitor 236.
The operational amplifier 232 is loaded with positive 12V voltage and negative 12V voltage；The reverse phase of the operational amplifier 232 is defeated
Enter end to connect by the 4th resistance 233 with the output end of the RC filter circuit 221；The operational amplifier 232 it is same
Phase input terminal is separately connected one end of the 5th resistance 234 and one end of the 6th resistance 235；5th resistance 234 it is another
Non-inverting input terminal of the one end as operation amplifier circuit 205；The other end of 6th resistance 235 is grounded；The operation is put
The output end of big device 232 connect the both ends of the first capacitor 236 with the inverting input terminal of operational amplifier 232；The operation
The output end of amplifier 232 is also connected with the third pin connecting pin B1 of number adjustable potentiometer described in Fig. 9 229；The operation
The inverting input terminal of amplifier 232 is also connected with the first pin connecting pin A1 of number adjustable potentiometer described in Fig. 9 229.
It is specific as shown in figure 11, the power amplifier circuit 206 include: power amplifier 237, the 7th resistance 238,
8th resistance 239, the 9th resistance 240 and the tenth resistance 241.
The power amplifier 237 is loaded with positive 12V voltage and negative 12V voltage；The reverse phase of the power amplifier 237 is defeated
Enter end to connect by the 8th resistance 239 with the output end of the operational amplifier 232 in Figure 10；The power amplifier
237 non-inverting input terminal is separately connected one end of the 9th resistance 240 and one end of the tenth resistance 241；9th resistance
Non-inverting input terminal of 240 other end as the power amplifier circuit 206；The other end of tenth resistance 241 is grounded；
The output end of the power amplifier 237 connect the two of the 7th resistance 238 with the inverting input terminal of power amplifier 237
End；The output end of the power amplifier 237 is also used in conjunction in the one end for connecing the secondary winding coil 214.
Specific as shown in figure 12, the direct current calibration signal generation circuit 209 includes: direct current calibration operational amplifier
242, eleventh resistor 243, twelfth resistor 244 and the second capacitor 245.
The direct current calibration operational amplifier 242 is loaded with positive 12V voltage and negative 12V voltage；The direct current calibrates operation
The inverting input terminal of amplifier 242 passes through the eleventh resistor 243 and the digital adjustable potentiometer 229 shown in Fig. 9
6th pin connecting pin W2 connection；The non-inverting input terminal of the direct current calibration operational amplifier 242 passes through the twelfth resistor
244 connect with the output end of direct current calibration operational amplifier 242；The output end of the direct current calibration operational amplifier 242
Also it is grounded by second capacitor 245；The output end of the direct current calibration operational amplifier 242 is calibrated as the direct current to be believed
The output end of number generation circuit 209.
Specific as shown in figure 13, the demagnetization signal generating circuit 208 includes: demagnetization operational amplifier the 246, the 13rd
Resistance 247, the 14th resistance 248, the 15th resistance 249, the 16th resistance 250, third capacitor 251, the 4th capacitor 252 and
5th capacitor 253.
The demagnetization operational amplifier 246 is loaded with positive 12V voltage and negative 12V voltage；The demagnetization operational amplifier 246
Inverting input terminal pass through the 14th resistance 248 be grounded；The non-inverting input terminal of the demagnetization operational amplifier 246 passes through the
It is grounded after the parallel circuit of four capacitors 252 and the 15th resistance 249 composition；The homophase input of the demagnetization operational amplifier 246
The demagnetization operational amplifier is connected after the series circuit that end is also made up of the 5th capacitor 253 and the 16th resistance 250
246 output end；The output end of the demagnetization operational amplifier 246 is loaded with degaussing control signal；The demagnetization operation amplifier
It is grounded after the parallel circuit that the output end of device 246 is also made up of the third capacitor 251 and thirteenth resistor 247；It is described to disappear
Output end of the output end of magnetic operational amplifier 246 as the demagnetization signal generating circuit 208.
For demagnetization signal generating circuit 208 shown in Figure 13, it is understood that, the ferromagnetic material of high magnetic permeability can
It is exactly that the magnetic that direction alternately changes can be generated by AC signal driving coil by applying opposing magnetic field appropriate
, demagnetization can be carried out to magnetic core with the magnetic field.Or apply high temperature or vibration to it to reach decrease or eliminate remanent magnetism.At this
Magnetic core is exactly placed in alternating magnetic field by the demagnetization method used in inventive embodiments, it is made to lose magnetism.Firstly, design is sinusoidal
Wave generation circuit generates sinusoidal signal, as demagnetization signal, generates magnetic direction with the sinusoidal signal driving coil and alternately changes
Magnetic field, the demagnetization of magnetic core is carried out with the magnetic field.And the demagnetization signal is to be added to by operational amplifier on the coil of magnetic head,
Signal generates direction alternating changing magnetic field on coil, also, its range value is also gradually reduced, and the mesh of demagnetization can be realized
's.Demagnetization signal generating circuit 208 in Figure 13 can use Wien bridge circuit oscillating circuit.The circuit can generate certain amplitude one
Determine the sinusoidal signal of frequency, the sinusoidal signal is finally input to one direction of generation in coil and replaces changing magnetic field at any time
For carrying out demagnetization to magnetic core.
In addition, as shown in figure 14, which can use Butterworth filter circuit.Wherein the Bart is fertile
The left end of this filter circuit connects transmission cable 223, and right end connects the second parallel end connection resistance 225 and high frequency connectors
226。
In addition, as shown in figure 15, which can be realized using output impedance match circuit.
Wherein the left end of the output impedance match circuit connects above-mentioned Butterworth filter circuit, and right end connects high frequency connectors
226。
In addition, as shown in figure 16, which can use high frequency output terminal BNC (Bayonet Nut
Connector it) realizes.Wherein high frequency output terminal BNC can connect the AFE(analog front end) 301 of oscillograph 30 (in Figure 16 not
It shows).
A kind of current probe provided in an embodiment of the present invention, by the way that two output ends of Hall sensor are separately connected difference
Divide amplifier circuit non-inverting input terminal and inverting input terminal, and not one end ground connection of Hall sensor, the other end connect difference
Amplifier circuit avoids asymmetry of the hall device due to bias voltage itself so that the output of Hall sensor balances, and is not having
There is signal output to cause the problem of the measurement result inaccuracy of current probe in the case where having measured conductor.In addition, the present invention is real
The circuit structure that example preferably selects the three-level signal of difference amplifier, operational amplifier and power amplifier to amplify is applied, and is led to
It crosses demagnetization signal generating circuit and direct current calibration signal generation circuit and by demagnetization signal and direct current calibration signal while introducing respectively
It, can be at any time to closed magnetic core into the magnetic head row demagnetization of formation in the case where not influencing current measurement in current probe circuit
And offset correction is carried out, it can be to avoid the problem of the measurement result inaccuracy of current probe in the prior art.In addition, the three-level
The first order of the circuit structure of signal amplification uses differential amplifier circuit, has and inhibits common-mode noise well, improves signal matter
The effect of amount.
In addition, it is worth noting that, the embodiment of the present invention can pass through micro-control unit (Microcontroller
Unit, abbreviation MCU) control each road signal and switch, to apply the current probe, to realize demagnetization and direct current calibration
Automatic operation.
It should be understood by those skilled in the art that, the embodiment of the present invention can provide as method, system or computer program
Product.Therefore, complete hardware embodiment, complete software embodiment or reality combining software and hardware aspects can be used in the present invention
Apply the form of example.Moreover, it wherein includes the computer of computer usable program code that the present invention, which can be used in one or more,
The computer program implemented in usable storage medium (including but not limited to magnetic disk storage, CD-ROM, optical memory etc.) produces
The form of product.
The present invention be referring to according to the method for the embodiment of the present invention, the process of equipment (system) and computer program product
Figure and/or block diagram describe.It should be understood that every one stream in flowchart and/or the block diagram can be realized by computer program instructions
The combination of process and/or box in journey and/or box and flowchart and/or the block diagram.It can provide these computer programs
Instruct the processor of general purpose computer, special purpose computer, Embedded Processor or other programmable data processing devices to produce
A raw machine, so that being generated by the instruction that computer or the processor of other programmable data processing devices execute for real
The device for the function of being specified in present one or more flows of the flowchart and/or one or more blocks of the block diagram.
These computer program instructions, which may also be stored in, is able to guide computer or other programmable data processing devices with spy
Determine in the computer-readable memory that mode works, so that it includes referring to that instruction stored in the computer readable memory, which generates,
Enable the manufacture of device, the command device realize in one box of one or more flows of the flowchart and/or block diagram or
The function of being specified in multiple boxes.
These computer program instructions also can be loaded onto a computer or other programmable data processing device, so that counting
Series of operation steps are executed on calculation machine or other programmable devices to generate computer implemented processing, thus in computer or
The instruction executed on other programmable devices is provided for realizing in one or more flows of the flowchart and/or block diagram one
The step of function of being specified in a box or multiple boxes.
Specific embodiment is applied in the present invention, and principle and implementation of the present invention are described, above embodiments
Explanation be merely used to help understand method and its core concept of the invention；At the same time, for those skilled in the art,
According to the thought of the present invention, there will be changes in the specific implementation manner and application range, in conclusion in this specification
Appearance should not be construed as limiting the invention.
Claims (12)
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|---|---|---|---|
| CN201710431464.1A CN109030906A (en) | 2017-06-09 | 2017-06-09 | A kind of current probe |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710431464.1A CN109030906A (en) | 2017-06-09 | 2017-06-09 | A kind of current probe |
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| CN110261765A (en) * | 2019-06-12 | 2019-09-20 | 沈阳工业大学 | A kind of the multi signal detection experimental rig and method of residual charge voltage |
| CN113804940A (en) * | 2021-09-23 | 2021-12-17 | 华东光电集成器件研究所 | High-precision closed-loop Hall current sensor circuit |
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Application publication date: 20181218 |