CN108957100A - A kind of current detection means - Google Patents
A kind of current detection means Download PDFInfo
- Publication number
- CN108957100A CN108957100A CN201810842316.3A CN201810842316A CN108957100A CN 108957100 A CN108957100 A CN 108957100A CN 201810842316 A CN201810842316 A CN 201810842316A CN 108957100 A CN108957100 A CN 108957100A
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- resistance
- triode
- electrically connected
- current source
- source circuit
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- 238000001514 detection method Methods 0.000 title claims abstract description 38
- 238000005070 sampling Methods 0.000 claims abstract description 19
- 230000005611 electricity Effects 0.000 claims description 6
- 230000003321 amplification Effects 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
Classifications
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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 provides a kind of current detection means, not only can effectively be detected to electric current, and at low cost, while can avoid the problem of ground level interferes again, applied widely；It includes power supply, sampling resistor, it further includes detection resistance, constant current source circuit structure, image current source circuit structure, the detection resistance, image current source circuit structure, sampling resistor, constant current source circuit structural order are electrically connected to form closed circuit, and by the power supply power supply.
Description
Technical field
The present invention relates to technical field of circuit control, specially a kind of current detection means.
Background technique
In power electronic technique, it is often necessary to the electric current loaded in detection circuit, convenient for being converted into institute in control system
The signal needed more preferably controls or makes corresponding protection to realize, mostly in circuit at present is to carry out electric current using amplifier
Detection, amplifier current detection mode are divided into high side current detection and low side current detecting again, wherein when being detected using high side current
There is a situation where that common-mode voltage is relatively high, therefore usually require to use dedicated and accurate device, cost is relatively high；And it uses low
When the current detecting of side, although cost is relatively low, the resistance for detecting electric current can introduce grounding interference, and electric current is bigger, suffered
Interference is just more obvious, so that restricted application.
Summary of the invention
For existing current detection technology, there are at high cost, and it is easily introduced grounding interference, restricted application is asked
Topic, the present invention provides a kind of current detection means, not only can effectively be detected to electric current, and at low cost, while again may be used
Avoid the problem that ground level interferes, it is applied widely.
Its technical solution is such that it includes power supply, sampling resistor, it is characterised in that: it further includes detection resistance, perseverance
Constant current source circuit structure, image current source circuit structure, the detection resistance, image current source circuit structure, sampling resistor,
Constant current source circuit structural order is electrically connected to form closed circuit, and by the power supply power supply；
The constant current source circuit structure includes resistance R1, R2, R3, NPN type triode Q1, Q3, the collection of the triode Q1
Electrode is electrically connected with one end of the base stage of the triode Q3, resistance R3, the emitter and the resistance of the triode Q3
It is grounded after R1 connection, and the base stage of the triode Q1 is electrically connected between the triode Q3, resistance R1, the triode Q3
Collector be electrically connected the resistance R2 after be electrically connected with the image current source circuit structure, the other end of the resistance R3 and
The sampling resistor electrical connection, the emitter ground connection of the triode Q1；
The image current source circuit structure includes resistance R4, R6, PNP type triode Q2, Q4, and the sampling resistor is electrically connected to
Between described resistance R4, R6, collector, the emitter of the triode Q2 respectively corresponds the electrical connection resistance R6, detection electricity
Resistance, the base stage of the triode Q2 are electrically connected with the base stage of the triode Q4, emitter and the resistance R2, and described three
The collector of pole pipe Q4 is electrically connected the resistance R4, and the positive pole is electrically connected with the resistance R6, the power cathode and
The detection resistance electrical connection.
It is further characterized by:
It further includes load resistance R_load, and one end of the load resistance R_load is electrically connected with the resistance R3, the other end
It is electrically connected with the emitter of the triode Q1；The resistance R4 is identical with the parameter of resistance R6, the triode Q2 and three poles
The parameter of pipe Q4 is identical.
The invention has the advantages that by being connected with image current source circuit structure, constant current source circuit structure, when
Load current changes in entire circuit, that is, the electric current for flowing through sampling resistor changes, then the voltage at sampling resistor both ends
It changes, and the variation of sampling resistor voltage, it can be embodied directly in the voltage change of detection resistance, so as to according to detection
The variation of the voltage at resistance both ends is not only at low cost to detect the electric current for flowing through and loading in entire circuit, and can avoid ground level
It is the problem of interference, applied widely.
Detailed description of the invention
Fig. 1 is circuit diagram of the invention.
Specific embodiment
As shown in Figure 1, the present invention includes power Vcc, sampling resistor Rsense, detection resistance R7, constant current source circuit
Structure, image current source circuit structure, detection resistance R7, image current source circuit structure, sampling resistor Rsense, constant current
Source circuit structure sequence is electrically connected to form closed circuit, and is powered by power Vcc；One end of load resistance R_load and resistance R3
Electrical connection, the other end are electrically connected with the emitter of triode Q1；
Constant current source circuit structure includes resistance R1, R2, R3, NPN type triode Q1, Q3, the collector of triode Q1 and three
The base stage of pole pipe Q3, one end of resistance R3 are electrically connected, and the emitter of triode Q3 is grounded after connecting with resistance R1, and triode
The base stage of Q1 is electrically connected between triode Q3, resistance R1, after the collector electric connection resistance R2 of triode Q3 with image current
Source circuit structure electrical connection, the other end of resistance R3 are electrically connected with sampling resistor Rsense, the emitter ground connection of triode Q1；
Image current source circuit structure includes resistance R4, R6, PNP type triode Q2, Q4, and sampling resistor Rsense is electrically connected to electricity
It hinders between R4, R6, collector, the emitter of triode Q2 respectively corresponds electric connection resistance R6, detection resistance R7, triode Q2's
Base stage is electrically connected with the base stage of triode Q4, emitter and resistance R2, the collector electric connection resistance R4 of triode Q4, electricity
Source Vcc anode is electrically connected with resistance R6, and power Vcc cathode is electrically connected with detection resistance R7；The parameter phase of resistance R4 and resistance R6
Together, triode Q2 is identical with the parameter of triode Q4.
The working principle of the invention is: resistance R1, R2, R3, NPN type triode Q1, Q3 are electrically connected to form constant current source
Circuit structure, as pull-up resistor, triode Q1, Q3's resistance R3 work in amplification region, after triode Q1 work, triode
The transmitting junction voltage of Q1 is constant, i.e. VBE_Q1It is constant, resistance R1 both end voltage can be obtained at this time, i.e., 1 voltage V1=in figure
VBE_Q1, then the electric current for flowing through resistance R1 isThe amplification factor of triode Q1, Q3 are β, then flowing through triode Q3
Electric current Ic_Q3 be equal to and flow through the electric current of resistance R1, and because resistance R2 and triode Q3 are electrically connected in series, so flowing through resistance R2
Electric current be equal to IR1, then after resistance R1 parameter is selected, the electric current for flowing through it is only related with the transmitting junction voltage of triode Q1, no
It is influenced by system power supply voltage and current.
Resistance R4, R6, triode Q2, Q4 be electrically connected to form image current source circuit structure, then resistance R4 and resistance R6
Parameter is identical, and triode Q2 is identical with the parameter of triode Q4, and two three poles can be ignored in amplification region in triode Q2, Q4 work
The influence of the base current of pipe, it is known that the electric current for flowing through triode Q4 is constant, and is equal to and flows through R2, triode Q3 and resistance R1
Electric current because resistance R4 and triode Q4 series connection, flow through resistance R4 electric current be equal to triode Q4 electric current；
When then no current flows through in original state, entire circuit, by image current source circuit structure it is found that then flowing through detection
The electric current of resistance R7 is equal to the electric current for flowing through triode Q2, is also equal to flow through the electric current of triode Q4, i.e., I at this timeR7:=IR1, that
Detection resistance R7 both end voltage is UR7:=IR1·R7, wherein UR7It is exactly the V marked in figure_out, i.e. V_out=UR7；
When having electric current I to flow through in entire circuit, the loop being made of resistance R4, Rsense, R6, triode Q2, Q4 is used
Kirchhoff's second law can be calculated
VR6+VBE_Q2:=IRsense+VR4+V BE_Q4, (1)
Since triode Q2 is identical with the parameter of triode Q4, then VBE_Q2:=VBE_Q4, (2)
V can be obtained in simultaneous (1), (2) formulaR6:=IRsense+VR4, (3)
And flow through the both ends resistance R6 electric current are as follows:
Resistance R6, triode Q2, detection resistance R7 series connection, that is, the electric current flowed through is equal, is IR7:=IR6, (5)
Detection resistance R7 both end voltage at this time are as follows: UR7:=IR7 ·R7, (6)
Simultaneous (3)~(6) formula is available
Then when entire circuit no current is with there is electric current, the voltage difference at the both ends detection resistance R7 is
It can be seen that the electric current for flowing through sampling resistor Rsense changes, then samples when entire circuital current changes
Resistance R_sense both end voltage changes, and the variation of sampling resistor R_sense voltage, can be embodied directly in detection resistance
In the voltage change of R7, so that entire circuit can be by the voltage at the both ends detection resistance R7 come detection circuit electric current, present invention electricity
Line structure is equivalent to using existing high side current detection mode, that is, avoids the problem that being interfered by ground level, and not by existing
There is the influence of amplifier common-mode voltage, low in cost, the electric current being particularly suitable in motor control or Switching Power Supply control field
Detection circuit, while the resistance value of resistance R6, R7 can be adjusted according to actual needs to adjust the range of detectable electric current, it answers
It is wider with range.
With reference to attached drawing and provided description, to help to various embodiments of the present invention defined by claim
Comprehensive understanding；It includes various specific details to help the understanding, but these details should be considered as being only exemplary；Such as
The load mentioned in this patent is ohmic load, but the loadtype in the present invention is unlimited, can be ohmic load, or
Capacitive load, inductive load or motor load etc.；Correspondingly, it will be appreciated by those of ordinary skill in the art that without departing substantially from by
In the case where the scope of the present invention defined by appended claims, change can be made to various embodiments described herein
Change and improves；In addition, for clarity and brevity, the description to known circuit may be omitted.
Claims (2)
1. a kind of current detection means comprising power supply, sampling resistor, it is characterised in that: it further includes detection resistance, constant electricity
Current source circuit structure, image current source circuit structure are the detection resistance, image current source circuit structure, sampling resistor, constant
Current source circuit structural order is electrically connected to form closed circuit, and by the power supply power supply；
The constant current source circuit structure includes resistance R1, R2, R3, NPN type triode Q1, Q3, the collection of the triode Q1
Electrode is electrically connected with one end of the base stage of the triode Q3, resistance R3, the emitter and the resistance of the triode Q3
It is grounded after R1 connection, and the base stage of the triode Q1 is electrically connected between the triode Q3, resistance R1, the triode Q3
Collector be electrically connected the resistance R2 after be electrically connected with the image current source circuit structure, the other end of the resistance R3 and
The sampling resistor electrical connection, the emitter ground connection of the triode Q1；
The image current source circuit structure includes resistance R4, R6, PNP type triode Q2, Q4, and the sampling resistor is electrically connected to
Between described resistance R4, R6, collector, the emitter of the triode Q2 respectively corresponds the electrical connection resistance R6, detection electricity
Resistance, the base stage of the triode Q2 are electrically connected with the base stage of the triode Q4, emitter and the resistance R2, and described three
The collector of pole pipe Q4 is electrically connected the resistance R4, and the positive pole is electrically connected with the resistance R6, the power cathode and
The detection resistance electrical connection.
2. a kind of current detection means according to claim 1, it is characterised in that: it further includes load resistance R_load,
One end of the load resistance R_load is electrically connected with the resistance R3, the emitter of the other end and the triode Q1 is electrically connected
It connects；The resistance R4 is identical with the parameter of resistance R6, and the triode Q2 is identical with the parameter of triode Q4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810842316.3A CN108957100A (en) | 2018-07-27 | 2018-07-27 | A kind of current detection means |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810842316.3A CN108957100A (en) | 2018-07-27 | 2018-07-27 | A kind of current detection means |
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| CN108957100A true CN108957100A (en) | 2018-12-07 |
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| CN201810842316.3A Pending CN108957100A (en) | 2018-07-27 | 2018-07-27 | A kind of current detection means |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111175568A (en) * | 2020-01-13 | 2020-05-19 | 北京中庆现代技术股份有限公司 | Structure for realizing POC detection and power supply protection |
| CN112485494A (en) * | 2020-11-17 | 2021-03-12 | 天津津航计算技术研究所 | Current detection circuit based on triode |
| CN115128327A (en) * | 2022-06-30 | 2022-09-30 | 杭州衡驰科技有限公司 | High-side current detection method for switching power supply |
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| CN103743934A (en) * | 2013-12-23 | 2014-04-23 | 延锋伟世通电子科技（上海）有限公司 | High-precision high-side current detection circuit |
| CN104897943A (en) * | 2015-04-30 | 2015-09-09 | 中国电子科技集团公司第五十八研究所 | High-sensitivity low-power current detection circuit |
| CN207051377U (en) * | 2017-07-06 | 2018-02-27 | 中国第一汽车股份有限公司 | High side current sample circuit |
| CN208537614U (en) * | 2018-07-27 | 2019-02-22 | 无锡雷利电子控制技术有限公司 | Current detection means |
-
2018
- 2018-07-27 CN CN201810842316.3A patent/CN108957100A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103743934A (en) * | 2013-12-23 | 2014-04-23 | 延锋伟世通电子科技（上海）有限公司 | High-precision high-side current detection circuit |
| CN104897943A (en) * | 2015-04-30 | 2015-09-09 | 中国电子科技集团公司第五十八研究所 | High-sensitivity low-power current detection circuit |
| CN207051377U (en) * | 2017-07-06 | 2018-02-27 | 中国第一汽车股份有限公司 | High side current sample circuit |
| CN208537614U (en) * | 2018-07-27 | 2019-02-22 | 无锡雷利电子控制技术有限公司 | Current detection means |
Non-Patent Citations (1)
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| 杨兴明主编: "电子设计竞赛基础与实践", 31 July 2012, 合肥工业大学出版社, pages: 152 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111175568A (en) * | 2020-01-13 | 2020-05-19 | 北京中庆现代技术股份有限公司 | Structure for realizing POC detection and power supply protection |
| CN112485494A (en) * | 2020-11-17 | 2021-03-12 | 天津津航计算技术研究所 | Current detection circuit based on triode |
| CN115128327A (en) * | 2022-06-30 | 2022-09-30 | 杭州衡驰科技有限公司 | High-side current detection method for switching power supply |
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