CN109818586A - A kind of current signal amplifier circuit, current signal detection circuit and detection method - Google Patents
A kind of current signal amplifier circuit, current signal detection circuit and detection method Download PDFInfo
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- CN109818586A CN109818586A CN201910094021.7A CN201910094021A CN109818586A CN 109818586 A CN109818586 A CN 109818586A CN 201910094021 A CN201910094021 A CN 201910094021A CN 109818586 A CN109818586 A CN 109818586A
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Abstract
The invention discloses a kind of current signal amplifier circuit, current signal detection circuit and detection methods, are related to power supply applied technical field.Circuit of the present invention can accurately amplify faint current signal, there is no bleeder circuits in traditional amplifying circuit, influence of the common-mode voltage to detection circuit is avoided, overcomes traditional amplifying circuit due to the problem using detection accuracy deficiency caused by excessive divider resistance.Meanwhile circuit structure is simple, the resistance quantity of use is seldom, improves the precision of detection circuit；Voltage signal on inspection leakage resistance is sent to the positive input terminal and negative input end of operational amplifier, a profound and negative feedbck circuit is made of operational amplifier and metal-oxide-semiconductor, since current signal amplifier circuit input resistance is very big, to hardly form influence, the high reliablity of circuit to the voltage signal on inspection leakage resistance.
Description
Technical field
The present invention relates to power supply applied technical field, it is specifically related to a kind of current signal amplifier circuit, current signal inspection
Slowdown monitoring circuit and detection method.
Background technique
Current detecting is very extensive in power supply application, is required to carry out in scenes such as power management, circuit protection designs
Current detecting.
There are two types of the method for current detecting is usual: one is detect electricity using magnetic field induction principle by hall device
The advantages of stream, the program is hardly to introduce power loss, is suitble to high current scene detection, especially in low-voltage, high-current field
Scape.But this method haves the shortcomings that at high cost, occupied space is big, cost pressure is big, operative scenario of high power density not
It is suitble to.
The common electric current detecting method of another of current detecting is realized using inspection leakage resistance, and method is:
Inspection leakage resistance is sealed in current loop, and electric current is calculated by the voltage on detection inspection leakage resistance.In order to reduce on inspection leakage resistance
Pressure drop and power consumption, examine the resistance value of leakage resistance usually all very little, the also very little of detection voltage thereon, usually millivolt level, due to
The voltage is very low, if directly carrying out sampling and A/D transformation to it, detection accuracy will be difficult to ensure, so usually will be to the electricity
Pressure is reprocessed after amplifying.Voltage amplifier circuit is usually that operational amplifier composition amplifying circuit is used to realize.But
More divider resistance is needed using the difference output of scaling circuit, is limited to the precision of resistance, caused by common mode interference
Measurement error is difficult to eliminate, if measurement error caused by common-mode voltage is larger, influences whether the reliability and effect of circuit.
Summary of the invention
The purpose of the invention is to overcome the shortcomings of above-mentioned background technique, a kind of current signal amplifier circuit, electricity are provided
Signal deteching circuit and detection method are flowed, realizes high-precision, the current detection scheme of high reliability.
The present invention provides a kind of current signal amplifier circuit, including operational amplifier, first resistor R1, second resistance R2 and
Metal-oxide-semiconductor；
The one end first resistor R1 connects the just defeated of operational amplifier for connecting inspection leakage resistance RS electric current input side, the other end
Enter foot；
The negative input foot of operational amplifier connects metal-oxide-semiconductor grid for connecting inspection leakage resistance RS electric current outlet side, output end；
Metal-oxide-semiconductor source electrode connects the positive input foot of operational amplifier, and metal-oxide-semiconductor drain electrode is grounded by second resistance R2.
The present invention also provides a kind of current detection circuits, including inspection leakage resistance RS, current signal amplifier circuit and signal to adopt
Collect unit, current signal amplifier circuit includes operational amplifier, first resistor R1, second resistance R2 and metal-oxide-semiconductor；
It examines leakage resistance RS electric current input side and connects electric current to be measured, electric current outlet side connects the negative input foot of operational amplifier；
The one end first resistor R1 connection inspection leakage resistance RS electric current input side, the other end connect the positive input of operational amplifier
Foot, operational amplifier output terminal connect metal-oxide-semiconductor grid；
Metal-oxide-semiconductor source electrode connects the positive input foot of operational amplifier, and metal-oxide-semiconductor drain electrode is grounded by second resistance R2；
Signal acquisition unit is set between metal-oxide-semiconductor and second resistance R2, for acquiring the voltage signal on second resistance R2.
Voltage on the basis of above scheme, on the second resistance R2 are as follows:VRSFor
Examine the voltage on leakage resistance RS.
On the basis of above scheme, the signal acquisition unit is also used to: second electricity of signal acquisition unit acquisition
After the voltage signal for hindering R2, A/D conversion process is carried out.
On the basis of above scheme, the resistance sizes of inspection leakage resistance RS are milliohm grade, for converting electric current to be measured to
Voltage signal.
The present invention also provides a kind of electric current detecting methods based on the current detection circuit, comprising the following steps:
Inspection leakage resistance RS and first resistor R1 is set to be separately connected electric current to be measured；
Operational amplifier and metal-oxide-semiconductor form a negative-feedback circuit, and the output voltage signal of operational amplifier drives metal-oxide-semiconductor
Conducting resistance variation, until the positive input foot and the pressure difference of negative input foot of operational amplifier are zero；
The voltage or current signal on second resistance R2 are acquired by signal acquisition unit.
On the basis of above scheme, after the voltage signal that second resistance R2 is acquired by signal acquisition unit, also wrap
Include following steps:
According to the resistance value of the first resistor R1 of selection, second resistance R2, the voltage magnitude on second resistance R2 is calculated.
Voltage on the basis of above scheme, on the second resistance R2 are as follows:VRSFor
Examine the voltage on leakage resistance RS.
It further include following step after the voltage signal that R2 is acquired by signal acquisition unit on the basis of above scheme
It is rapid:
According to the voltage magnitude on second resistance R2, the resistance value of optimal first resistor R1, second resistance R2 are calculated.
On the basis of above scheme, after voltage or current signal that R2 is acquired by signal acquisition unit, further include
Following steps:
The signal acquisition unit carries out A/D conversion process.
Compared with prior art, advantages of the present invention is as follows:
Circuit of the present invention can accurately amplify faint current signal, and there is no divide electricity in traditional amplifying circuit
Road avoids influence of the common-mode voltage to detection circuit, overcomes traditional amplifying circuit due to leading using excessive divider resistance
The problem of the detection accuracy deficiency of cause.Meanwhile circuit structure is simple, the resistance quantity of use is seldom, improves detection circuit
Precision；
Voltage signal on inspection leakage resistance is sent to the positive input terminal and negative input end of operational amplifier, by operational amplifier and
Metal-oxide-semiconductor constitutes a profound and negative feedbck circuit, since current signal amplifier circuit input resistance is very big, thus on inspection leakage resistance
Voltage signal hardly form influence, the high reliablity of circuit；
Operational amplifier has very high bandwidth, and entire current detection circuit does not use reactive device, therefore has
Sufficiently high bandwidth is able to respond the quick variation of electric current.
Detailed description of the invention
To describe the technical solutions in the embodiments of the present invention more clearly, a letter is made to the corresponding attached drawing of embodiment below
Singly introduce, it should be apparent that, drawings in the following description are some embodiments of the invention, for ordinary skill people
For member, without creative efforts, it is also possible to obtain other drawings based on these drawings.
Fig. 1 is the current signal amplifier circuit of the embodiment of the present invention and the structural schematic diagram of current detection circuit.
Specific embodiment
Term explanation:
Metal-oxide-semiconductor: metal-oxide-semiconductor is metal (metal), oxide (oxide), semiconductor (semiconductor) field-effect crystalline substance
Body pipe, or claim to be metal-insulator (insulator), semiconductor.
Examine leakage resistance: i.e. current sense resistor, also known as electric current inductive reactance, English are
Currentsensingresistor samples the electric current for flowing through the device with reaching with detected devices in series.Inspection
The voltage at leakage resistance both ends is directly proportional to electric current to be measured, after voltage is amplified device amplification, provides corresponding voltage or electric current driving.
With reference to the accompanying drawing and specific embodiment the present invention is described in further detail.
Shown in Figure 1, the embodiment of the present invention provides a kind of current signal amplifier circuit, spy include operational amplifier,
R1, R2 and metal-oxide-semiconductor；
The one end R1 connects the positive input foot of operational amplifier for connecting inspection leakage resistance RS electric current input side, the other end；
The negative input foot of operational amplifier connects metal-oxide-semiconductor grid for connecting inspection leakage resistance RS electric current outlet side, output end；
Metal-oxide-semiconductor source electrode connects the positive input foot of operational amplifier, and metal-oxide-semiconductor drain electrode is grounded by R2.
Circuit of the embodiment of the present invention can accurately amplify faint current signal, and there is no in traditional amplifying circuit points
Volt circuit avoids influence of the common-mode voltage to detection circuit, overcomes traditional amplifying circuit due to using excessive divider resistance
Caused by detection accuracy deficiency problem.Meanwhile circuit structure is simple, the resistance quantity of use is seldom, improves detection electricity
The precision on road.Operational amplifier has very high bandwidth, and entire current detection circuit does not use reactive device, therefore has
Sufficiently high bandwidth is able to respond the quick variation of electric current.
The embodiment of the present invention also provides a kind of current detection circuit, including inspection leakage resistance RS, current signal amplifier circuit and
Signal acquisition unit.
It examines leakage resistance RS electric current input side and connects electric current to be measured, electric current outlet side connects the negative input foot of operational amplifier；
The resistance sizes for examining leakage resistance RS are milliohm grade, for converting voltage signal for electric current to be measured.Current signal sampling passes through inspection
Leakage resistance RS resistance is completed, the usual very little of the resistance, is milliohm grade, and electric current flows through the pressure that the resistance will generate millivolt level on it
Drop, the voltage and electric current direct proportionality, the voltage will reflect current signal.The circuit design is universal circuit, non-reality
A summary of the invention is applied, but it is as signal source, is component part indispensable in the present embodiment circuit.
Current signal amplifier circuit includes operational amplifier, R1, R2 and metal-oxide-semiconductor；The one end R1 connects electric current to be measured, the other end
The positive input foot of operational amplifier is connected, operational amplifier output terminal connects metal-oxide-semiconductor grid；Metal-oxide-semiconductor source electrode connects operation amplifier
The positive input foot of device, metal-oxide-semiconductor drain electrode are grounded by second resistance R2.
Signal acquisition unit is set between metal-oxide-semiconductor and R2, for acquiring voltage or current signal on R2.
Current signal amplifier circuit circuit works in profound and negative feedbck state, utilizes " empty short " concept it is found that inspection leakage resistance
Voltage on R1 is equal to the voltage on RS, then flowing through the electric current on R1 is the voltage on resistance RS divided by resistance R1, i.e. VRS/
R1, the electric current flow through R2 to ground through MOSFET.
Voltage on the resistance R2 are as follows:VRSFor the voltage on inspection leakage resistance RS.
After selected R1, R2, then Vcurrent by with the voltage direct proportionality on RS, that is to say, that Vcurrent
By relationship proportional to detected current signal, by selecting suitable R1, R2 resistance value, available required voltage amplitude
Value；Optimal resistance value can also be chosen according to required voltage magnitude and driving capability.Signal acquisition unit obtains accurately
After Vcurrent voltage, relevant processing, such as A/D transformation can be carried out to it.
Circuit of the present invention can accurately amplify faint current signal, and there is no divide electricity in traditional amplifying circuit
Road avoids influence of the common-mode voltage to detection circuit, overcomes traditional amplifying circuit due to leading using excessive divider resistance
The problem of the detection accuracy deficiency of cause.Meanwhile circuit structure is simple, the resistance quantity of use is seldom, improves detection circuit
Precision.Operational amplifier has very high bandwidth, and entire current detection circuit does not use reactive device, therefore has enough
High bandwidth is able to respond the quick variation of electric current.
The embodiment of the present invention is sent to the positive input terminal of operational amplifier by the voltage signal on inspection leakage resistance RS and bears defeated
Enter end, a profound and negative feedbck circuit is made of operational amplifier and metal-oxide-semiconductor, very due to current signal amplifier circuit input resistance
Greatly, to hardly form influence, the high reliablity of circuit to the voltage signal on inspection leakage resistance.
The advantages of current detection circuit of the embodiment of the present invention, is as follows:
There is no divider resistances usually existing in conventional operational amplifiers scheme, since there are precision mistakes for divider resistance
Difference, then the common mode interference examined on stream signal translates into DM EMI, to reduce the precision of detection voltage；
Circuit structure is simple, minimizes the usage quantity of resistance, to also be conducive to improve detection accuracy；
Voltage signal on inspection leakage resistance is sent to the positive input terminal and negative input end of operational amplifier, and operational amplifier is constituted
One profound and negative feedbck circuit, input impedance is very big, so that influence is hardly formed on the voltage signal on inspection leakage resistance, electricity
The high reliablity on road；
Amplified current signal voltage value can be adjusted by two resistance, and regulative mode is simple and reliable；Pass through adjusting
This two resistance, so that suitable voltage value can be obtained, e.g., rear class uses A/D conversion circuit, by adjusting this two resistance,
Current signal voltage value may make to take optimum amplitude, to improve A/D conversion accuracy, to improve current detection accuracy；
Usual operational amplifier has very high bandwidth, and detection circuit does not use reactive device, entire current signal
Amplifying circuit has very high bandwidth, and fast-changing current signal can be responded fast, accurately；
Can demand according to late-class circuit to driving capability, the resistance value of two resistance of flexible choice.
The embodiment of the present invention provides a kind of electric current detecting method using current detection circuit, comprising the following steps:
Inspection leakage resistance RS and first resistor R1 is set to be separately connected electric current to be measured；
Operational amplifier and metal-oxide-semiconductor form a negative-feedback circuit, and the output voltage signal of operational amplifier drives metal-oxide-semiconductor
Conducting resistance variation, until the positive input foot and the pressure difference of negative input foot of operational amplifier are zero；
The voltage or current signal on second resistance R2 are acquired by signal acquisition unit.
Voltage on the resistance R2 are as follows:VRSFor the voltage on inspection leakage resistance RS.
As limited embodiment, the method also includes following steps: the electricity of R2 is acquired by signal acquisition unit
After pressure or current signal, according to R1, R2 resistance value of selection, the voltage magnitude on R2 is calculated.
As limited embodiment, the method also includes following steps: the electricity of R2 is acquired by signal acquisition unit
After pressure or current signal, according to the voltage magnitude on required R2, optimal R1, R2 resistance value is calculated.
As limited embodiment, the method also includes following steps: the electricity of R2 is acquired by signal acquisition unit
After pressure or current signal, A/D conversion process is carried out.
Amplified current signal voltage value can be adjusted by two resistance, and regulative mode is simple and reliable；Pass through adjusting
This two resistance, so that suitable voltage value can be obtained, e.g., rear class uses A/D conversion circuit, by adjusting this two resistance,
Current signal voltage value may make to take optimum amplitude, to improve A/D conversion accuracy, to improve current detection accuracy；
Usual operational amplifier has very high bandwidth, and detection circuit does not use reactive device, entire current signal
Amplifying circuit has very high bandwidth, and fast-changing current signal can be responded fast, accurately；
Can demand according to late-class circuit to driving capability, the resistance value of two resistance of flexible choice.
Obviously, various changes and modifications can be made to the invention without departing from essence of the invention by those skilled in the art
Mind and range.In this way, if these modifications and changes of the present invention belongs to the range of the claims in the present invention and its equivalent technologies
Within, then the present invention is also intended to include these modifications and variations.
Claims (10)
1. a kind of current signal amplifier circuit, it is characterised in that: including operational amplifier, first resistor R1, second resistance R2 and
Metal-oxide-semiconductor；
The one end first resistor R1 connects the positive input of operational amplifier for connecting inspection leakage resistance RS electric current input side, the other end
Foot；
The negative input foot of operational amplifier connects metal-oxide-semiconductor grid for connecting inspection leakage resistance RS electric current outlet side, output end；
Metal-oxide-semiconductor source electrode connects the positive input foot of operational amplifier, and metal-oxide-semiconductor drain electrode is grounded by second resistance R2.
2. a kind of current detection circuit, it is characterised in that: including inspection leakage resistance RS, current signal amplifier circuit and signal acquisition list
Member, current signal amplifier circuit include operational amplifier, first resistor R1, second resistance R2 and metal-oxide-semiconductor；
It examines leakage resistance RS electric current input side and connects electric current to be measured, electric current outlet side connects the negative input foot of operational amplifier；
The one end first resistor R1 connection inspection leakage resistance RS electric current input side, the other end connect the positive input foot of operational amplifier, fortune
It calculates amplifier out and connects metal-oxide-semiconductor grid；
Metal-oxide-semiconductor source electrode connects the positive input foot of operational amplifier, and metal-oxide-semiconductor drain electrode is grounded by second resistance R2；
Signal acquisition unit is set between metal-oxide-semiconductor and second resistance R2, for acquiring the voltage signal on second resistance R2.
3. current detection circuit as claimed in claim 2, it is characterised in that: the voltage on the second resistance R2 are as follows:VRSFor the voltage on inspection leakage resistance RS.
4. current detection circuit as claimed in claim 2, it is characterised in that: the signal acquisition unit is also used to: the letter
After the voltage signal of number acquisition unit acquisition second resistance R2, A/D conversion process is carried out.
5. current detection circuit as claimed in claim 2, it is characterised in that: the resistance sizes of inspection leakage resistance RS are milliohm grade,
For converting voltage signal for electric current to be measured.
6. a kind of electric current detecting method based on current detection circuit as claimed in claim 2, which is characterized in that including following
Step:
Inspection leakage resistance RS and first resistor R1 is set to be separately connected electric current to be measured；
Operational amplifier and metal-oxide-semiconductor form a negative-feedback circuit, and the output voltage signal driving metal-oxide-semiconductor of operational amplifier is led
Logical resistance variations, until the positive input foot of operational amplifier and the pressure difference of negative input foot are zero；
The voltage or current signal on second resistance R2 are acquired by signal acquisition unit.
7. method as claimed in claim 6, it is characterised in that: believed by the voltage that signal acquisition unit acquires second resistance R2
It is further comprising the steps of after number:
According to the resistance value of the first resistor R1 of selection, second resistance R2, the voltage magnitude on second resistance R2 is calculated.
8. the method for claim 7, it is characterised in that: the voltage on the second resistance R2 are as follows:VRSFor the voltage on inspection leakage resistance RS.
9. method as claimed in claim 6, it is characterised in that: after the voltage signal for acquiring R2 by signal acquisition unit,
It is further comprising the steps of:
According to the voltage magnitude on second resistance R2, the resistance value of optimal first resistor R1, second resistance R2 are calculated.
10. method as claimed in claim 6, it is characterised in that: acquire the voltage of R2 by signal acquisition unit or electric current is believed
It is further comprising the steps of after number:
The signal acquisition unit carries out A/D conversion process.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910094021.7A CN109818586A (en) | 2019-01-30 | 2019-01-30 | A kind of current signal amplifier circuit, current signal detection circuit and detection method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910094021.7A CN109818586A (en) | 2019-01-30 | 2019-01-30 | A kind of current signal amplifier circuit, current signal detection circuit and detection method |
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| CN109818586A true CN109818586A (en) | 2019-05-28 |
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| CN201910094021.7A Pending CN109818586A (en) | 2019-01-30 | 2019-01-30 | A kind of current signal amplifier circuit, current signal detection circuit and detection method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110763922A (en) * | 2019-11-01 | 2020-02-07 | 龙迅半导体（合肥）股份有限公司 | Differential reference voltage generation circuit, peak signal detection circuit, and electronic device |
| CN112947218A (en) * | 2021-03-02 | 2021-06-11 | 江苏润石科技有限公司 | Precision improving circuit and method of current detection amplifier |
| CN114184878A (en) * | 2021-10-27 | 2022-03-15 | 天津工业大学 | Circuit breaker short circuit performance test circuit |
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| JP2002017036A (en) * | 2000-06-29 | 2002-01-18 | Nissan Motor Co Ltd | Over-current detection circuit |
| CN101029910A (en) * | 2007-03-22 | 2007-09-05 | 华为技术有限公司 | Current inspecting circuit and device |
| JP2014239332A (en) * | 2013-06-07 | 2014-12-18 | 株式会社デンソー | Current detector |
| CN105548654A (en) * | 2015-12-02 | 2016-05-04 | 中国电子科技集团公司第四十一研究所 | Circuit and method for weak current detection |
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2019
- 2019-01-30 CN CN201910094021.7A patent/CN109818586A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002017036A (en) * | 2000-06-29 | 2002-01-18 | Nissan Motor Co Ltd | Over-current detection circuit |
| CN101029910A (en) * | 2007-03-22 | 2007-09-05 | 华为技术有限公司 | Current inspecting circuit and device |
| JP2014239332A (en) * | 2013-06-07 | 2014-12-18 | 株式会社デンソー | Current detector |
| CN105548654A (en) * | 2015-12-02 | 2016-05-04 | 中国电子科技集团公司第四十一研究所 | Circuit and method for weak current detection |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110763922A (en) * | 2019-11-01 | 2020-02-07 | 龙迅半导体（合肥）股份有限公司 | Differential reference voltage generation circuit, peak signal detection circuit, and electronic device |
| CN112947218A (en) * | 2021-03-02 | 2021-06-11 | 江苏润石科技有限公司 | Precision improving circuit and method of current detection amplifier |
| CN114184878A (en) * | 2021-10-27 | 2022-03-15 | 天津工业大学 | Circuit breaker short circuit performance test circuit |
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