CN103336165A - Detection circuit for overcurrent of alternating current and direct current - Google Patents

Detection circuit for overcurrent of alternating current and direct current Download PDF

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Publication number
CN103336165A
CN103336165A CN2013102553052A CN201310255305A CN103336165A CN 103336165 A CN103336165 A CN 103336165A CN 2013102553052 A CN2013102553052 A CN 2013102553052A CN 201310255305 A CN201310255305 A CN 201310255305A CN 103336165 A CN103336165 A CN 103336165A
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China
Prior art keywords
current
photoelectrical coupler
circuit
resistor
detection circuit
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CN2013102553052A
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Chinese (zh)
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CN103336165B (en
Inventor
李平
邵明绪
张庞源
刘淑芳
王新怀
史小卫
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Xidian Univ
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Xidian Univ
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Publication of CN103336165B publication Critical patent/CN103336165B/en
Expired - Fee Related legal-status Critical Current
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Abstract

The invention discloses a detection circuit for overcurrent of alternating current and direct current. The detection circuit is composed of a first photoelectric coupler (U1), a second photoelectric coupler (U2), a sampling resistor (R1), a current-limiting resistor (R2), a pull-up resistor (R3), system input 1 (IN1), system input 2 (IN2) and system output (OUT), wherein the sampling resistor (R1) is used for measuring the current, the sampling resistor (R1) and the current-limiting resistor (R2) set the overcurrent detection threshold, the first photoelectric coupler (U1), the second photoelectric coupler (U2) and the pull-up resistor (R3) perform signal transformation, and overcurrent signals are output. The detection current is simple in structure, is low in cost, is suitable for the overcurrent detection of the alternating current and the direct current and can be used for the overcurrent detection of high potential at the same time.

Description

A kind of alternating current-direct current over-current detection circuit
Technical field
The invention belongs to the detection technique field, relate in particular to a kind of alternating current-direct current over-current detection circuit, applicable to the over-current detection in alternating circuit and the DC circuit, and can be used for the over-current detection of noble potential.
Background technology
At all electronic equipments or product a rated current is arranged, do not allow to surpass rated current, otherwise can reduce greatly the serviceable life of electron device, even burn out equipment.This just needs the current protection module, when electric current surpasses the setting electric current, provides over-current signal, and equipment can cut off the power supply automatically according to over-current signal, with protection equipment.Existing over-current detection circuit is of a great variety, mostly complex structure; The circuit complexity directly causes cost to raise, and circuit too complexity also causes labile factor to increase, and has reduced the stability of circuit; And existing over-current detection circuit seldom has the circuit that can detect AC and DC simultaneously; When some special applications, such as requiring over-current detection not influence under earthy situation, then over-current detection circuit must be placed on the higher position of current potential in the circuit, most over-current detection circuits do not possess noble potential over-current detection function.
Summary of the invention
The objective of the invention is to design a kind of alternating current-direct current over-current detection circuit of simple in structure and low in cost, be suitable for the over-current detection circuit of AC and DC electric power system simultaneously, and can be connected detection electric current in optional position in the circuit.
Technical scheme of the present invention is: a kind of alternating current-direct current over-current detection circuit mainly is made of first photoelectrical coupler, second photoelectrical coupler, sampling resistor, current-limiting resistance, pull-up resistor and system's output; Wherein an end of sampling resistor and system input 1 is connected, be connected with an end of current-limiting resistance simultaneously, the other end of sampling resistor is imported 2 with system and is connected, and is connected with the negative electrode of the first photoelectrical coupler internal body diodes and the anode of the second photoelectrical coupler internal body diodes respectively simultaneously; The other end of current-limiting resistance is connected with the anode of the first photoelectrical coupler internal body diodes and the negative electrode of the second photoelectrical coupler internal body diodes respectively; First photoelectrical coupler all is connected with ground with the emitter of the inner phototriode of second photoelectrical coupler; First photoelectrical coupler is connected with an end of pull-up resistor with the collector of the inner phototriode of second photoelectrical coupler, connected system output simultaneously; The other end of pull-up resistor connects power supply.
Described sampling resistor is serially connected in alternating circuit or the DC circuit by system's input 1 and system's input 2.
Principle of work of the present invention is: sampling resistor is connected in the loop of circuit, converts the current signal in the circuit to corresponding voltage signal by sampling resistor.When measuring the electric current of AC system, when terminal voltage is higher than the lower end on the sampling resistor, current-limiting resistance and the first photoelectrical coupler interior light emitting diodes constitute the loop, the second photoelectrical coupler interior light emitting diodes is reverse, electric current is zero, this moment, second photoelectrical coupler was inoperative, and over-current signal is exported by first photoelectrical coupler; When terminal voltage under the sampling resistor is higher than the upper end, current-limiting resistance and the second photoelectrical coupler interior light emitting diodes constitute the loop, and the first photoelectrical coupler interior light emitting diodes is reverse, and electric current is zero, this moment, first photoelectrical coupler was inoperative, and over-current signal is exported by second photoelectrical coupler; When measuring the electric current of straight-flow system, over-current detection circuit only is operated in a kind of state of measuring when exchanging, have only first photoelectrical coupler or second photoelectrical coupler both one of work; Circuit is by adjusting the size of sampling resistor and current-limiting resistance, and the electric current of photoelectrical coupler interior light emitting diodes is flow through in control, and then the thresholding of control over-current detection output.
Advantage of the present invention is: other reasons such as overweight or ac circuit short circuit causes that the ac circuit electric current is excessive when motor load; when surpassing 200mA; over-current detection circuit output OUT is low level; control system detects incoming level by high step-down; adjust output; K switch 1 is opened, and overcurrent protection is played in the ac circuit outage.Circuit structure of the present invention is simply with low cost, is suitable for the over-current detection circuit of AC and DC electric power system simultaneously, and can be connected detection electric current in optional position in the circuit.
Description of drawings
The invention will be further described below in conjunction with design drawing:
Fig. 1 is the circuit diagram of a kind of alternating current-direct current over-current detection circuit of the present invention;
Fig. 2 is the use synoptic diagram of a kind of alternating current-direct current over-current detection circuit of the present invention in ac circuit;
Among Fig. 1: U1, first photoelectrical coupler; U2, second photoelectrical coupler; R1, sampling resistor; R2, current-limiting resistance; R3, pull-up resistor; IN1, system's input 1; IN2 system input 2; OUT, system's output.
Among Fig. 2: a, ac circuit; B, over-current detection circuit; C, control system.
Embodiment
Be the circuit diagram of a kind of alternating current-direct current over-current detection circuit of the present invention as shown in Figure 1, comprise the first photoelectrical coupler U1, the second photoelectrical coupler U2, sampling resistor R1, current-limiting resistance R2, pull-up resistor R3 and the output OUT of system; Wherein the end of sampling resistor R1 is connected with the end of current-limiting resistance R2, and the other end of sampling resistor R1 is connected with the negative electrode of the first photoelectrical coupler U1 internal body diodes and the anode of the second photoelectrical coupler U2 internal body diodes respectively; The other end of current-limiting resistance R2 is connected with the anode of the first photoelectrical coupler U1 internal body diodes and the negative electrode of the second photoelectrical coupler U2 internal body diodes respectively; The first photoelectrical coupler U1 is connected with ground GND with the emitter of the inner phototriode of the second photoelectrical coupler U2; The first photoelectrical coupler U1 is connected with the end of pull-up resistor R3 with the collector of the inner phototriode of the second photoelectrical coupler U2, the OUT of connected system output simultaneously; The other end of pull-up resistor R3 connects power supply VCC.Sampling resistor R1 is serially connected in alternating circuit or the DC circuit.
During use, this over-current detection circuit being connected between circuit loop and the control system, is example with the alternating circuit, and as Fig. 2, a is ac circuit, mainly comprises AC power U1, motor M1 and gauge tap K1; B is over-current detection circuit of the present invention, sampling resistor R1 resistance is 7.5 Ω, current-limiting resistance R2 resistance is 470 Ω, photoelectrical coupler U1 and U2 adopt PC817, the pull-up resistor resistance is 10K, can calculate according to the resistance of R1 and R2 characteristic selected and photoelectrical coupler PC817, this circuit overcurrent thresholding is about 200mA; C is control system, and control system can be by the detection to the input end high-low level, control output end output.
Over-current detection circuit is serially connected in sampling resistor R1 in the ac circuit by IN1 and IN2, and the output OUT of over-current detection circuit is connected with the input of control system, and the output of control system connects the K switch 1 of ac circuit, the break-make of control ac circuit.During the system operate as normal, electric current is less than 200mA in the circuit, and over-current detection circuit output OUT is high level, and the control system output signal is normal, K switch 1 closure, and ac circuit runs well.Other reasons such as overweight or ac circuit short circuit causes that the ac circuit electric current is excessive when motor load; when surpassing 200mA; over-current detection circuit output OUT is low level; control system detects incoming level by high step-down; adjust output; K switch 1 is opened, and overcurrent protection is played in the ac circuit outage.
Above embodiment does not constitute any restriction to content of the present invention to of the present invention with reference to explanation, obviously under thought of the present invention, can make multi-form structure modify, but these are all at the row of protection of the present invention.
The part that present embodiment is not described in detail and english abbreviation belong to the common practise of the industry, can search on the net, here not narration one by one.

Claims (2)

1. alternating current-direct current over-current detection circuit is characterized in that comprising: first photoelectrical coupler (U1), second photoelectrical coupler (U2), sampling resistor (R1), current-limiting resistance (R2), pull-up resistor (R3), the input 1(IN1 of system), the input 2(IN2 of system) and system export (OUT); Wherein an end of sampling resistor (R1) and system import 1(IN1) be connected, be connected with an end of current-limiting resistance (R2) simultaneously, the other end of sampling resistor (R1) and the input 2(IN2 of system) be connected, be connected with the negative electrode of first photoelectrical coupler (U1) internal body diodes and the anode of second photoelectrical coupler (U2) internal body diodes respectively simultaneously; The other end of current-limiting resistance (R2) is connected with the anode of first photoelectrical coupler (U1) internal body diodes and the negative electrode of second photoelectrical coupler (U2) internal body diodes respectively; The emitter of first photoelectrical coupler (U1) and the inner phototriode of second photoelectrical coupler (U2) all is connected with ground (GND); The collector of first photoelectrical coupler (U1) and the inner phototriode of second photoelectrical coupler (U2) is connected with an end of pull-up resistor (R3), simultaneously connected system output (OUT); The other end of pull-up resistor (R3) connects power supply (VCC).
2. a kind of alternating current-direct current over-current detection circuit according to claim 1 is characterized in that described sampling resistor (R1) is by the input 1(IN1 of system) and the input 2(IN2 of system) be serially connected in alternating circuit to be measured or the DC circuit.
CN201310255305.2A 2013-06-25 2013-06-25 A kind of alternating current-direct current over-current detection circuit Expired - Fee Related CN103336165B (en)

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105119501A (en) * 2015-08-26 2015-12-02 长沙奥托自动化技术有限公司 Pre-charging circuit for low-voltage frequency converter and pre-charging method
CN105576599A (en) * 2016-03-15 2016-05-11 西安科技大学 Overcurrent or short-circuit fault signal isolation detection circuit and design method thereof
CN106569015A (en) * 2015-10-13 2017-04-19 泰科电子(上海)有限公司 AC load detection circuit
CN106645898A (en) * 2016-12-23 2017-05-10 苏州佳世达光电有限公司 Current detecting circuit and current detecting apparatus
CN107782957A (en) * 2016-08-31 2018-03-09 北京智乐精仪科技有限公司 Differential voltage detection method and battery voltage detector in the presence of common-mode voltage
CN109725190A (en) * 2019-03-25 2019-05-07 贵州航天天马机电科技有限公司 A kind of alternating current-direct current signal multiple sampling protection system
CN111929609A (en) * 2019-04-25 2020-11-13 株洲中车时代电气股份有限公司 Short circuit detection device for digital output channel

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CN201681118U (en) * 2010-05-27 2010-12-22 朱晓 Output current detection device of high voltage electric field and electric potential therapeutic apparatus
CN201757764U (en) * 2009-11-05 2011-03-09 中国石油大学(华东) Simple general type full wave zero-crossing detection circuit
CN201811989U (en) * 2010-09-07 2011-04-27 佘明 Direct-current high-voltage indicating device
CN102749501A (en) * 2012-08-01 2012-10-24 电子科技大学 Isolated direct current high voltage detection method and isolated direct current high voltage detection circuit
CN202903859U (en) * 2012-11-05 2013-04-24 重庆艾尤旺科技有限公司 AC current detection alarm circuit

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5745233A (en) * 1996-02-06 1998-04-28 Tsubakimoto Chain Co. Voltage detecting circuit
CN201757764U (en) * 2009-11-05 2011-03-09 中国石油大学(华东) Simple general type full wave zero-crossing detection circuit
CN201681118U (en) * 2010-05-27 2010-12-22 朱晓 Output current detection device of high voltage electric field and electric potential therapeutic apparatus
CN201811989U (en) * 2010-09-07 2011-04-27 佘明 Direct-current high-voltage indicating device
CN102749501A (en) * 2012-08-01 2012-10-24 电子科技大学 Isolated direct current high voltage detection method and isolated direct current high voltage detection circuit
CN202903859U (en) * 2012-11-05 2013-04-24 重庆艾尤旺科技有限公司 AC current detection alarm circuit

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105119501A (en) * 2015-08-26 2015-12-02 长沙奥托自动化技术有限公司 Pre-charging circuit for low-voltage frequency converter and pre-charging method
CN106569015A (en) * 2015-10-13 2017-04-19 泰科电子(上海)有限公司 AC load detection circuit
CN106569015B (en) * 2015-10-13 2019-10-18 泰科电子(上海)有限公司 AC load detection circuit
CN105576599A (en) * 2016-03-15 2016-05-11 西安科技大学 Overcurrent or short-circuit fault signal isolation detection circuit and design method thereof
CN105576599B (en) * 2016-03-15 2018-04-13 西安科技大学 A kind of overcurrent or short circuit fault signal isolation detection circuit and its design method
CN107782957A (en) * 2016-08-31 2018-03-09 北京智乐精仪科技有限公司 Differential voltage detection method and battery voltage detector in the presence of common-mode voltage
CN106645898A (en) * 2016-12-23 2017-05-10 苏州佳世达光电有限公司 Current detecting circuit and current detecting apparatus
CN106645898B (en) * 2016-12-23 2019-12-03 苏州佳世达光电有限公司 Current-sensing circuit and current sense device
CN109725190A (en) * 2019-03-25 2019-05-07 贵州航天天马机电科技有限公司 A kind of alternating current-direct current signal multiple sampling protection system
CN109725190B (en) * 2019-03-25 2020-11-03 贵州航天天马机电科技有限公司 Alternating current-direct current signal multiple sampling protection system
CN111929609A (en) * 2019-04-25 2020-11-13 株洲中车时代电气股份有限公司 Short circuit detection device for digital output channel

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