CN103033668A - Electric current detection circuit - Google Patents

Electric current detection circuit Download PDF

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Publication number
CN103033668A
CN103033668A CN2012105545142A CN201210554514A CN103033668A CN 103033668 A CN103033668 A CN 103033668A CN 2012105545142 A CN2012105545142 A CN 2012105545142A CN 201210554514 A CN201210554514 A CN 201210554514A CN 103033668 A CN103033668 A CN 103033668A
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China
Prior art keywords
detection circuit
electric current
current detection
current
comparer
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CN2012105545142A
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CN103033668B (en
Inventor
何欢潮
何伟峰
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Guangzhou Feida Audio Co ltd
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Guangzhou Fidek Professional Audio Equipment Co Ltd
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Priority to CN201210554514.2A priority Critical patent/CN103033668B/en
Publication of CN103033668A publication Critical patent/CN103033668A/en
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Publication of CN103033668B publication Critical patent/CN103033668B/en
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  • Measurement Of Current Or Voltage (AREA)

Abstract

Disclosed is an electric current detection circuit. According to the electric current detection circuit, difference between voltages at two ends of a sense resistor is detected by electrical current to detect electrical current flowing through the sense resistor. One end of the electric current detection circuit is grounded, and the other end of the electric current detection circuit is connected with an object which is detected. The electric current detection circuit is characterized in that the electrical current passes an inductor, and flows to a divider resistor and a positive phase foot of a comparator in a split-type mode. The electric current which flows through the divider resistor flows to a negative phase foot of the comparator and another branch circuit. The electric current detection circuit is simple in structure and area of a printed circuit board (PCB) is saved. Further, the electric current detection circuit has the advantages of being low in electric quantity which is consumed, quite small in calorific value, high in sensitivity and capable of improving safety performance of the detection circuit, current changes can be responded very well, and the electric current detection circuit plays a role in fast protection of charging equipment in a charging process.

Description

Current detection circuit
Technical field
The present invention relates to the current detection circuit that a kind of difference of utilizing the both end voltage of current sense resistor detects the electric current that flows through described current sense resistor.
Background technology
Current detection circuit is to configure current sense resistor at current path, utilizes the difference of the both end voltage of current sense resistor to detect the electric current that flows through described current sense resistor.In sort circuit, wish to reduce as far as possible the resistance value of current sense resistor, thereby reduce the pressure drop here as far as possible; On the other hand, when the pressure drop on the current sense resistor diminishes, be difficult to detect this pressure drop, in the time of particularly will detecting Weak current, must detect very little voltage difference, it is very difficult that current detecting becomes.
At present, traditional current detecting electric current is the size of coming the decision circuitry electric current by the voltage difference at comparison resistance two ends, yet works as the electric weight of electric current loss on resistance, causes the comparision of quantity of electricity of resistance needs large.Under so large loss, position and the space of the corresponding relatively large shared pcb board of the volume of resistance are larger.And resistance is in the situation that long-term fever high temperature, and the life-span also shortens relatively, more likely can cause because electric current is excessive the dangerous phenomenons such as burning.Traditional current detection circuit can detect electric current more than 150mA in addition, and this electric current can unstable even cisco unity malfunction when electric current was too small.
Usually can exist sensitivity low in this current detection circuit, electric energy loss is large, the problem such as the low and security performance of efficient is low.
Summary of the invention
There is the problem that sensitivity is low, electric energy loss is large, efficient is low and security performance is low in order to overcome traditional current detection circuit; the invention provides a kind of current detection circuit; not only simple in structure; saved the area of PCB; and the electric weight of loss is low, thermal value is minimum, highly sensitive; improved the security performance of testing circuit, well response current changes, and charging equipment is played Immediate Protective Effects when charging.
The technical solution adopted for the present invention to solve the technical problems is: a kind of current detection circuit, to utilize the difference of the both end voltage of current sense resistor to detect the electric current that flows through described current sense resistor, one end ground connection of current detection circuit, the other end connects object to be detected, it is characterized in that: described electric current is through inductance, be diverted to the positive pin of divider resistance and comparer, the circuit that flows through divider resistance is diverted to negative pin and another branch road of comparer.
The positive pin of described comparer is during greater than the negative pin, the output pin of comparer output high level, and the triode conducting, the low signal of trigger end output is received microprocessor and is processed, and detects the size of testee electric current.
The positive pin of described comparer is less than the negative pin, the output pin output low level of comparer, and the triode cut-off, the high signal of trigger end output is received microprocessor and is processed, and detects the size of testee electric current.
The invention has the beneficial effects as follows: current detection circuit is not only simple in structure; saved the area of PCB; and the electric weight of loss is low, thermal value is minimum, highly sensitive; improved the security performance of testing circuit; well response current changes, and charging equipment is played Immediate Protective Effects when charging.
Description of drawings
The invention will be further described below in conjunction with accompanying drawing and embodiment.
Fig. 1 is the LM393 current detection circuit.
Fig. 2 is the ZXCT1009 current detection circuit.
Embodiment
A kind of current detection circuit, to utilize the difference of the both end voltage of current sense resistor to detect the electric current that flows through described current sense resistor, one end ground connection of current detection circuit, the other end connects object to be detected, its electric current is through inductance, be diverted to the positive pin of divider resistance and comparer, the circuit that flows through divider resistance is diverted to negative pin and another branch road of comparer.
When the positive pin of comparer during greater than the negative pin, the output pin output high level of comparer, the triode conducting, the low signal of trigger end output is received microprocessor and is processed, and detects the size of testee electric current.
When the positive pin of comparer less than the negative pin, the output pin output low level of comparer, the triode cut-off, the high signal of trigger end output is received microprocessor and is processed, and detects the size of testee electric current.
As shown in Figure 1, LM393 comes the size of decision circuitry electric current by the voltage difference at the resistance two ends of 1R41 relatively, however when electric current is 2A when on 1R41 the electric weight of loss be 2W, thereby resistance 1R41 need are at least more than the 2W.Position and the space of the corresponding relatively large shared pcb board of the volume of 1R41 are larger under so large loss.And this resistance is in the situation that long-term fever high temperature, and the life-span is also relatively short, more likely can cause because electric current is excessive the dangerous phenomenons such as burning.LM393 can detect electric current more than 150mA in addition, and this electric current can unstable even cisco unity malfunction when electric current was too small.Generally speaking.With also can therefore shortening in serviceable life of the product of this scheme or having safety problem.
As shown in Figure 2, the ZXCT1009 voltage that only needed to detect approximately 0.01 ohm resistance two ends just can detect the approximately electric current of 100mA.Thereby the 1 pin output terminal of ZXCT1009 can well be identified by MCU by conducting and cut-off that the output high-low level promotes triode.If sensed current reaches more than the 1A, itself in addition can then can reach testing requirement by detecting a bit of circuit board copper sheet.ZXCT1009 detects R78---0.02 Ohmage both end voltage then can, when crossing 2A by R78 two ends electric current, its loss power is 0.04W just also.Therefore R78 resistance only needs 0805 encapsulation then can.Saved widely the area of PCB.Minimum thereby its security performance also can increase because of its loss lower calorific value.It is highly sensitive, thereby well response current changes, thereby fine to IPHONE, plays Immediate Protective Effects during the chargings such as IPOD.Improve the security of IPHONE fittings equipment, also protected well user's IPOD series products.
From cost, ZXCT1009 and LM393 price are of slight difference, differ relatively large yet detect used resistance price, the resistance price that LM393 is used, and it is large to account for the PCB area, and it is high that overall cost indirectly can turn relatively.Low and the superior performance of ZXCT1009 current detection circuit price is a design that cost performance is higher.

Claims (3)

1. current detection circuit, to utilize the difference of the both end voltage of current sense resistor to detect the electric current that flows through described current sense resistor, one end ground connection of current detection circuit, the other end connects object to be detected, it is characterized in that: described electric current is through inductance, be diverted to the positive pin of divider resistance and comparer, the circuit that flows through divider resistance is diverted to negative pin and another branch road of comparer.
2. current detection circuit according to claim 1, it is characterized in that: the positive pin of described comparer is during greater than the negative pin, the output pin output high level of comparer, the triode conducting, the low signal of trigger end output is received microprocessor and is processed, and detects the size of testee electric current.
3. current detection circuit according to claim 1, it is characterized in that: the positive pin of described comparer is less than the negative pin, the output pin output low level of comparer, triode cut-off, the high signal of trigger end output is received microprocessor and is processed, and detects the size of testee electric current.
CN201210554514.2A 2012-12-18 2012-12-18 Current detection circuit Active CN103033668B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201210554514.2A CN103033668B (en) 2012-12-18 2012-12-18 Current detection circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201210554514.2A CN103033668B (en) 2012-12-18 2012-12-18 Current detection circuit

Publications (2)

Publication Number Publication Date
CN103033668A true CN103033668A (en) 2013-04-10
CN103033668B CN103033668B (en) 2017-10-13

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107482909A (en) * 2017-07-28 2017-12-15 惠州市德赛西威汽车电子股份有限公司 A kind of line loss compensation circuit of power supply
CN110314309A (en) * 2019-05-14 2019-10-11 北京戴纳实验科技有限公司 A kind of laboratory fire-fighting robot
CN110335444A (en) * 2019-05-14 2019-10-15 北京戴纳实验科技有限公司 A kind of laboratory air leak diagnostic apparatus

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008026082A (en) * 2006-07-19 2008-02-07 Rohm Co Ltd Current sensing circuit, charge control circuit using it, charging circuit, and electronic device
CN102236402A (en) * 2010-04-26 2011-11-09 鸿富锦精密工业(深圳)有限公司 Energy saving detection circuit
CN202057719U (en) * 2011-03-29 2011-11-30 上海安泊易电子科技有限公司 High-side current detecting system
CN102315655A (en) * 2010-07-02 2012-01-11 东莞钜威新能源股份有限公司 Detection control circuit
CN202424265U (en) * 2012-02-09 2012-09-05 广州市君盘实业有限公司 Multifunctional intelligent charger based on single chip microcomputer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008026082A (en) * 2006-07-19 2008-02-07 Rohm Co Ltd Current sensing circuit, charge control circuit using it, charging circuit, and electronic device
CN102236402A (en) * 2010-04-26 2011-11-09 鸿富锦精密工业(深圳)有限公司 Energy saving detection circuit
CN102315655A (en) * 2010-07-02 2012-01-11 东莞钜威新能源股份有限公司 Detection control circuit
CN202057719U (en) * 2011-03-29 2011-11-30 上海安泊易电子科技有限公司 High-side current detecting system
CN202424265U (en) * 2012-02-09 2012-09-05 广州市君盘实业有限公司 Multifunctional intelligent charger based on single chip microcomputer

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107482909A (en) * 2017-07-28 2017-12-15 惠州市德赛西威汽车电子股份有限公司 A kind of line loss compensation circuit of power supply
CN110314309A (en) * 2019-05-14 2019-10-11 北京戴纳实验科技有限公司 A kind of laboratory fire-fighting robot
CN110335444A (en) * 2019-05-14 2019-10-15 北京戴纳实验科技有限公司 A kind of laboratory air leak diagnostic apparatus

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Address after: 510820, Guangzhou, Guangdong province Huadu District charcoal step Feida Industrial Park

Applicant after: FIRST AUDIO MANUFACTURING Co.,Ltd.

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Address after: 510820, Guangzhou, Guangdong province Huadu District charcoal step Feida Industrial Park

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Address before: 510820, Guangzhou, Guangdong province Huadu District charcoal step Feida Industrial Park

Patentee before: FIRST AUDIO MANUFACTURING Co.,Ltd.