CN107192871A - A kind of differential detection circuit of positive counter current - Google Patents
A kind of differential detection circuit of positive counter current Download PDFInfo
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- CN107192871A CN107192871A CN201710478576.2A CN201710478576A CN107192871A CN 107192871 A CN107192871 A CN 107192871A CN 201710478576 A CN201710478576 A CN 201710478576A CN 107192871 A CN107192871 A CN 107192871A
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- voltage
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- counter current
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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
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- General Physics & Mathematics (AREA)
- Measurement Of Current Or Voltage (AREA)
Abstract
The present invention relates to current detection technology field, specifically disclose a kind of differential detection circuit of positive counter current, provided with detection input, detection output, accurate sampling resistor is connected between the detection input and detection output, the two ends of the accurate sampling resistor are also respectively connected with the first voltage input and second voltage input of voltage conversion unit, the conversion voltage output end of the voltage conversion unit connects MCU voltage detecting end, the superimposed voltage input of the voltage conversion unit connects the superimposed voltage output end of voltage superposition unit, the voltage superposition unit is accessed initial superimposed voltage and is translated into after default superimposed voltage from the superimposed voltage output end and exported by its energization input.Implement a kind of differential detection circuit for positive counter current that the present invention is provided, sampling precision is up to 0.01%, and power is high, temperature coefficient is good；Can the positive counter current of sample detecting and accuracy in computation be high simultaneously, error is small.
Description
Technical field
The present invention relates to current detection technology field, more particularly to a kind of differential detection circuit of positive counter current.
Background technology
At present, automobile electronic system has more place to need to use current detecting during design, test and use
Circuit,, typically will not be using the side for directly detecting electric current in actual detection process such as compressor, motor, air blower
Formula, generally detects corresponding voltage U, it is known that corresponding resistance R, by calculating accordingly, obtains corresponding current value I, with
This is used as detection electric current.
Setting MCU (Micro Control Unit, a micro-control unit) analog port is used for detecting the port
Real-time voltage, and set two partial pressure sampling resistors to carry out partial pressure between the analog port and test point, by corresponding
Formula calculates the size of test point electric current.But, because the voltage deviation on the accuracy error of partial pressure sampling resistor, power supply ground
Etc. reason, cause MCU samplings inaccurate, meanwhile, such circuit can only sample detecting forward current, and can not sample detecting it is reverse
Electric current.
The content of the invention
The present invention provides a kind of differential detection circuit of positive counter current, solves the accurate sampling resistor of setting and carrys out real time differential
Sample positive counter current, the positive counter current is converted to by positive and negative voltage signal by voltage conversion unit, then pass through voltage superposition list
By it, the positive and negative voltage signal is converted into forward voltage signal to member, is finally output to MCU analog port --- voltage detecting end
Detect voltage to calculate the technical problem of electric current in real time.
To solve above technical problem, the present invention provides a kind of differential detection circuit of positive counter current, provided with detection input
End, detection output, are connected with accurate sampling resistor, the accurate sampling between the detection input and detection output
The two ends of resistance are also respectively connected with the first voltage input and second voltage input of voltage conversion unit, the voltage conversion
The conversion voltage output end of unit connects MCU voltage detecting end, the superimposed voltage input connection of the voltage conversion unit
The superimposed voltage output end of voltage superposition unit, the voltage superposition unit accesses initial superimposed voltage by its energization input
And be translated into after default superimposed voltage from superimposed voltage output end output.
Specifically, the voltage conversion unit be provided with the first operational amplifier, first operational amplifier it is same mutually defeated
The superimposed voltage input is connected after entering end connection the first electric capacity in parallel and first resistor.
Specifically, the detection input is connected after the in-phase input end connection second resistance of first operational amplifier
The detection output is connected after end, the inverting input connection 3rd resistor of first operational amplifier.
Specifically, connect after the reverse input end connection of first operational amplifier the 4th resistance in parallel and the second electric capacity
It is connected to the voltage output end of body.
Specifically, the voltage output end of first operational amplifier connects one end of the 5th resistance, the 5th resistance
The other end be the voltage conversion unit conversion voltage output end, the 3rd capacitance connection is in the conversion voltage output end
Between ground.
Specifically, the voltage superposition unit is provided with the second operational amplifier, the supply input of the voltage superposition unit
The in-phase input end of second operational amplifier is connected after the 6th resistance of end connection, the 7th resistance in parallel and the 4th electric capacity connect
It is connected between the in-phase input end of second operational amplifier and ground.
Specifically, the inverting input of second operational amplifier connects the voltage output end of its own, described second
The positive power source terminal access chip operating voltage of operational amplifier, positive supply of the 5th capacitance connection in second operational amplifier
Between end and ground, the negative power end ground connection of second operational amplifier.
Specifically, the voltage output end of second operational amplifier be the voltage superposition unit superimposed voltage it is defeated
Go out end.
A kind of differential detection circuit for positive counter current that the present invention is provided, sets accurate sampling resistor to carry out real time differential sampling
Positive counter current, sampling precision is up to 0.01%, and power is high, temperature coefficient is good；
The positive counter current is converted to by positive and negative voltage signal by voltage conversion unit, then by voltage superposition unit by its
The positive and negative voltage signal is converted into forward voltage signal, is finally output to MCU analog port --- and voltage detecting end is come direct
Voltage is detected in real time, so that according to the resistance of the accurate sampling resistor come calculating current, can be while the positive counter current of sample detecting
And accuracy in computation is high, error is small.
Brief description of the drawings
Fig. 1 is the circuit theory diagrams of existing current detection technology provided in an embodiment of the present invention；
Fig. 2 is the oscillogram of positive counter current provided in an embodiment of the present invention；
Fig. 3 is a kind of circuit theory diagrams of the differential detection circuit of positive counter current provided in an embodiment of the present invention；
Fig. 4 is a kind of MCU of the differential detection circuit of positive counter current provided in an embodiment of the present invention voltage detecting end
Voltage oscillogram.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Site preparation is described.The type selecting and value size of following component are only preferred embodiment, and the limit to the scope of the present invention is not constituted
System.
Referring to Fig. 1 is the circuit theory diagrams of existing current detection technology provided in an embodiment of the present invention, and Fig. 2 is the present invention
The oscillogram for the positive counter current that embodiment is provided.Shown in Fig. 1, existing current detection technology mainly uses MCU (Micro
Control Unit, micro-control unit) an analog port MCU_AD carry out sample detecting resistance R11 and R12 partial pressure, pass through
Corresponding formula calculates the corresponding electric currents of current detecting end I_A, and wherein resistance R13 and electric capacity C11 are analog port MCU_
AD RC resistance-capacitance circuits, play current limliting filtering.But, there is drawback, such as Fig. 1 circuits, partial pressure sampling in such circuit design
Because the accuracy error of detection resistance, power supply the ground reason such as GND voltage deviation, cause sampling inaccurate；Meanwhile, such circuit
Can only sample detecting forward current, it is impossible to sample detecting reverse current as shown in Figure 2.
For above drawback, the present invention devises a kind of differential detection circuit of positive counter current, can be widely used for automobile electricity
Subsystem, is similarly used in the current detecting in other circuit systems.It is one kind provided in an embodiment of the present invention referring to Fig. 3
The circuit theory diagrams of the differential detection circuit of positive counter current, provided with detection input I_B, detection output I_C, in the detection
Accurate sampling resistor R is connected between input I_B and detection output I_C, the two ends of the accurate sampling resistor R are also distinguished
Connect the first voltage input 11 and second voltage input 12 of voltage conversion unit 1, the conversion of the voltage conversion unit 1
Voltage output end 13 connects MCU voltage detecting end I_AD, and the superimposed voltage input 14 of the voltage conversion unit 1 connects electricity
The superimposed voltage output end 21 of superpositing unit 2 is pressed, the voltage superposition unit 2 accesses initial superposition by its energization input 22
Voltage and being translated into after default superimposed voltage from the superimposed voltage output end 21 is exported.
Preferably, the voltage conversion unit 1 is provided with the first operational amplifier U1, and the first operational amplifier U1's is same
The superimposed voltage input 14 is connected after phase input U1_PIN5 connections the first electric capacity C1 in parallel and first resistor R1.Institute
The detection input I_B, institute are connected after the in-phase input end U1_PIN5 connection second resistances R2 for stating the first operational amplifier U1
The detection output I_C is connected after the inverting input U1_PIN6 connection 3rd resistors R3 for stating the first operational amplifier U1.Institute
Connected certainly after the 4th resistance R4 and the second electric capacity C2 of the reverse input end U1_PIN6 connections parallel connection for stating the first operational amplifier U1
The voltage output end U1_PIN7 of body.The resistance R5's of voltage output end U1_PIN7 connections the 5th of the first operational amplifier U1
One end, the other end of the 5th resistance R5 is the conversion voltage output end 13 of the voltage conversion unit 1, the 3rd electric capacity C3
It is connected between the conversion voltage output end 13 and ground GND.
Preferably, the voltage superposition unit 2 is provided with the second operational amplifier U2, the power supply of the voltage superposition unit 2
Input 22 connects and the in-phase input end U2_PIN3 of the second operational amplifier U2 is connected after the 6th resistance R6, and in parallel the
Seven resistance R7 and the 4th electric capacity C4 are connected between the in-phase input end U2_PIN3 and ground GND of the second operational amplifier U2.
The inverting input U2_PIN2 of the second operational amplifier U2 connects the voltage output end U2_PIN1 of its own, described second
Operational amplifier U2 positive power source terminal U2_PIN4 access chip operating voltages VCC, the 5th electric capacity C5 is connected to second computing
Between amplifier U2 positive power source terminal U2_PIN4 and ground GND, the negative power end U2_PIN11 of the second operational amplifier U2 connects
Ground GND.The voltage output end U2_PIN1 of the second operational amplifier U2 is the superimposed voltage of the voltage superposition unit 2
Output end 21.The initial superimposed voltage is also the chip operating voltage VCC.
Its course of work and principle are illustrated below：
The circuit of electric current to be detected is entered from the detection input I_B, by accurate the sampling resistor R, Ran Houcong
Detection output I_C flows out, it is assumed that flow through the current waveform of the accurate sampling resistor R as shown in Fig. 2 being that positive counter current is maximum
Reach 1A sine-wave current；The second operational amplifier U2 (is typically adopted by the 6th resistance R6 and the 7th resistance R7
With resistance value identical resistance) partial pressure, finally export the default superimposed voltage from its voltage output end U2_PIN1 (21)
0.5VCC (the voltage 0.5VCC of chip operating voltage VCC half, it is assumed herein that VCC is 5V, 0.5VCC is 2.5V), then will
0.5VCC is added to the in-phase input end U1_PIN5 of the first operational amplifier U1 as the reference voltage, so as to draw MCU's
Voltage detecting end I_AD positive detectable voltage signals, as shown in figure 4, again by the resistance value of the accurate sampling resistor R and
Ohm's law calculates corresponding positive counter current；
Wherein, the accurate sampling resistor R is also referred to as current sense resistor, current sensing resistor, sample resistance, electric current sense
Resistance is answered, precision is up to 0.01%, there is 0.0005 Ω, 2m Ω, 3m Ω, 10m Ω equal-specifications, power is higher, temperature coefficient is preferable,
Depending on the specific size of current and use environment of type selecting and size according to detection；The chip operating voltage VCC is MCU power supply
Power supply, generally+5V or+3.3V, the 5th resistance R5 and the 3rd electric capacity C3 constitute the voltage detecting end I_AD of the MCU
The RC capacitance-resistance filters of (analog port), the first electric capacity C1, the second electric capacity C2, the 4th electric capacity C4, the 5th electric capacity C5 are
Filter capacitor, according to different occasions and the suitable value of performance selection.
Described above is the preferred embodiment of the present invention, it is noted that for those skilled in the art
For, under the premise without departing from the principles of the invention, some improvements and modifications can also be made, these improvements and modifications are also considered as
Protection scope of the present invention.
Claims (8)
1. a kind of differential detection circuit of positive counter current, it is characterised in that provided with detection input, detection output, described
Accurate sampling resistor is connected between detection input and detection output, the two ends of the accurate sampling resistor are also respectively connected with
The first voltage input and second voltage input of voltage conversion unit, the conversion voltage output end of the voltage conversion unit
Connect MCU voltage detecting end, the superposition electricity of the superimposed voltage input connection voltage superposition unit of the voltage conversion unit
Output end is pressed, the voltage superposition unit accesses initial superimposed voltage by its energization input and is translated into default superposition
Exported after voltage from the superimposed voltage output end.
2. a kind of differential detection circuit of positive counter current as claimed in claim 1, it is characterised in that：The voltage conversion unit
Provided with the first operational amplifier, the first electric capacity and first resistor of the in-phase input end connection parallel connection of first operational amplifier
After connect the superimposed voltage input.
3. a kind of differential detection circuit of positive counter current as claimed in claim 2, it is characterised in that：First operation amplifier
The detection input, the inverting input of first operational amplifier are connected after the in-phase input end connection second resistance of device
The detection output is connected after connection 3rd resistor.
4. a kind of differential detection circuit of positive counter current as claimed in claim 3, it is characterised in that：First operation amplifier
The voltage output end of itself is connected after the 4th resistance and the second electric capacity of the reverse input end connection parallel connection of device.
5. a kind of differential detection circuit of positive counter current as claimed in claim 4, it is characterised in that：First operation amplifier
The voltage output end of device connects one end of the 5th resistance, and the other end of the 5th resistance is turning for the voltage conversion unit
Voltage output end is changed, the 3rd capacitance connection is between the conversion voltage output end and ground.
6. a kind of differential detection circuit of positive counter current as described in claim 1 or 5, it is characterised in that：The voltage superposition
Unit is provided with the second operational amplifier, and the energization input of the voltage superposition unit connects described second after connecting the 6th resistance
The same phase of the in-phase input end of operational amplifier, the 7th resistance in parallel and the 4th capacitance connection in second operational amplifier
Between input and ground.
7. a kind of differential detection circuit of positive counter current as claimed in claim 6, it is characterised in that：Second operation amplifier
The inverting input of device connects the voltage output end of its own, the positive power source terminal access chip work of second operational amplifier
Voltage, the 5th capacitance connection between the positive power source terminal and ground of second operational amplifier, second operational amplifier
Negative power end is grounded.
8. a kind of differential detection circuit of positive counter current as claimed in claim 7, it is characterised in that：Second operation amplifier
The voltage output end of device is the superimposed voltage output end of the voltage superposition unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710478576.2A CN107192871A (en) | 2017-06-22 | 2017-06-22 | A kind of differential detection circuit of positive counter current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710478576.2A CN107192871A (en) | 2017-06-22 | 2017-06-22 | A kind of differential detection circuit of positive counter current |
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| Publication Number | Publication Date |
|---|---|
| CN107192871A true CN107192871A (en) | 2017-09-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710478576.2A Pending CN107192871A (en) | 2017-06-22 | 2017-06-22 | A kind of differential detection circuit of positive counter current |
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| Country | Link |
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| CN (1) | CN107192871A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108429461A (en) * | 2018-03-20 | 2018-08-21 | 惠州三华工业有限公司 | High-voltage power circuit |
| CN108808627A (en) * | 2018-08-08 | 2018-11-13 | 杭州先途电子有限公司 | A kind of controller |
| CN108896816A (en) * | 2018-08-15 | 2018-11-27 | 惠州市蓝微电子有限公司 | A kind of high precision electro current detection circuit of brshless DC motor |
| CN112596000A (en) * | 2020-12-02 | 2021-04-02 | 爱士惟新能源技术(江苏)有限公司 | Method and device for detecting reverse connection of PV input ends of photovoltaic inverters |
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|---|---|---|---|---|
| JP2004286657A (en) * | 2003-03-24 | 2004-10-14 | Mitsumi Electric Co Ltd | Current-sensing circuit |
| CN102654528A (en) * | 2012-04-13 | 2012-09-05 | 宁波德业变频技术有限公司 | Alternating current voltage sampling device for power factor correction |
| CN202929091U (en) * | 2012-12-06 | 2013-05-08 | 鸿宝电气集团股份有限公司 | Positive/back current one-way indicator ammeter |
| CN106501722A (en) * | 2016-09-02 | 2017-03-15 | 安徽锐普电子有限公司 | A kind of battery voltage detection circuit and detecting voltage method |
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2017
- 2017-06-22 CN CN201710478576.2A patent/CN107192871A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004286657A (en) * | 2003-03-24 | 2004-10-14 | Mitsumi Electric Co Ltd | Current-sensing circuit |
| CN102654528A (en) * | 2012-04-13 | 2012-09-05 | 宁波德业变频技术有限公司 | Alternating current voltage sampling device for power factor correction |
| CN202929091U (en) * | 2012-12-06 | 2013-05-08 | 鸿宝电气集团股份有限公司 | Positive/back current one-way indicator ammeter |
| CN106501722A (en) * | 2016-09-02 | 2017-03-15 | 安徽锐普电子有限公司 | A kind of battery voltage detection circuit and detecting voltage method |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108429461A (en) * | 2018-03-20 | 2018-08-21 | 惠州三华工业有限公司 | High-voltage power circuit |
| CN108429461B (en) * | 2018-03-20 | 2023-12-05 | 惠州三华工业有限公司 | High-voltage power supply circuit |
| CN108808627A (en) * | 2018-08-08 | 2018-11-13 | 杭州先途电子有限公司 | A kind of controller |
| CN108896816A (en) * | 2018-08-15 | 2018-11-27 | 惠州市蓝微电子有限公司 | A kind of high precision electro current detection circuit of brshless DC motor |
| CN112596000A (en) * | 2020-12-02 | 2021-04-02 | 爱士惟新能源技术(江苏)有限公司 | Method and device for detecting reverse connection of PV input ends of photovoltaic inverters |
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Application publication date: 20170922 |
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| RJ01 | Rejection of invention patent application after publication |