CN1848577A - Overcurrent protection circuit - Google Patents
Overcurrent protection circuit Download PDFInfo
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- CN1848577A CN1848577A CN 200510076853 CN200510076853A CN1848577A CN 1848577 A CN1848577 A CN 1848577A CN 200510076853 CN200510076853 CN 200510076853 CN 200510076853 A CN200510076853 A CN 200510076853A CN 1848577 A CN1848577 A CN 1848577A
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Abstract
A over current protective circuit consists of current sampling circuit connected to power supply and load for outputting the sampling voltage value of sampling current, control unit for confirming reference voltage value according to over current valve value, voltage output circuit connected to control unit for outputting reference voltage value confirmed by control unit and voltage comparator for comparing the sampling voltage value with reference voltage value and for being used to output over current signal to indicate power supply switch to switch power off when sampling voltage value is greater then reference voltage value.
Description
Technical field
The present invention relates to the circuit design technique field, relate in particular to a kind of current foldback circuit.
Background technology
In the traditional circuit technical field, current foldback circuit is a kind of a kind of circuit that can protect entire circuit under the excessive situation of the electric current of flowing through.
Please refer to Fig. 1, this figure is the application principle block diagram of existing current foldback circuit; The main effect of current foldback circuit 10 is the output currents that detect power supply among the figure, when detecting the electric current of flowing through above the predetermined electric current threshold values, closes automatically or deenergization.
Come in and with reference to Fig. 2, and this figure is the circuit theory composition frame chart of existing current foldback circuit; Traditional current foldback circuit is mainly finished overcurrent protection work jointly by following three functional units:
Wherein, make the minimum sample rate current value of voltage comparator 102 output overcurrent index signals be referred to as the overcurrent threshold values.
Above-mentioned current foldback circuit of the prior art can only could realize setting different overcurrent threshold values by the reference voltage level that adjusting reference voltage source 103 provides, promptly when needs are adjusted the overcurrent threshold values, can only could realize by the reference voltage level that modification reference voltage source 103 provides, therefore be not suitable for being applied in the application scenario that needs often to revise the overcurrent threshold values, the application scenario that wherein needs often to revise the overcurrent threshold values refers to the occasion that load often changes, so that different overcurrent threshold values need be set according to different loads; As the lowest high-current value that can allow to pass through when load is 1 ampere-hour, and overcurrent threshold values that can current foldback circuit is set to 1 ampere; When changing a bigger load, its lowest high-current value that can allow to pass through is 2 ampere-hours, just the overcurrent threshold values of current foldback circuit need be revised as 2 amperes.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of can be applied in the current foldback circuit that needs often to revise overcurrent threshold values application scenario.
For addressing the above problem, the technical scheme that the present invention proposes is as follows:
A kind of current foldback circuit comprises:
The current sampling circuit that connects power supply and load respectively is used for the electric current of the load of flowing through is sampled, and the sample voltage value of output sample rate current;
Control unit is used for determining reference voltage level according to the overcurrent threshold values that the load that current sampling circuit connects can bear;
The voltage follower circuit that is connected with control unit is used for the reference voltage level output that control unit is determined; With
Voltage comparator is used for the sample voltage value of current sampling circuit output and the reference voltage level of voltage follower circuit output are compared, and when sample voltage value is higher than reference voltage level, output overcurrent index signal indication mains switch power cutoff.
Wherein said current sampling circuit is the resistance that is connected on power output end.
Wherein said control unit specifically comprises:
The reference voltage level computation subunit is used for overcurrent threshold values that the load that current sampling circuit connects be can bear and the resistance value that is connected on power output end and multiplies each other, and obtains described reference voltage level;
The indication subelement is used to the reference voltage level output of indicating voltage follower circuit that the reference voltage level computation subunit is calculated.
Wherein said voltage follower circuit is a digital to analog converter; The control port of described digital to analog converter is connected with control unit, and output port is used for the output reference voltage value.
The beneficial effect that the present invention can reach is as follows:
The overcurrent threshold values that current foldback circuit of the present invention can bear by the load that will adopt electric resistance partial pressure or dedicated reference voltage source to provide the mode of reference voltage level to change in traditional current foldback circuit to be connected according to current sampling circuit by control unit is dynamically adjusted and is determined reference voltage level; and export to voltage comparator by the reference voltage level that voltage follower circuit is determined control unit; compare the sample voltage value of current sampling circuit output and the reference voltage level of voltage follower circuit output by voltage comparator; determining whether sending the overcurrent index signal, thereby reach the purpose of entire circuit being carried out overcurrent protection to mains switch.Because current foldback circuit of the present invention can connect the adjustment reference voltage level of the overcurrent threshold values dynamic flexible that load can bear according to current sampling circuit by control unit, therefore is applicable to because the frequent conversion of load needs causes taking the application scenario of normal modification overcurrent threshold values.
Description of drawings
Fig. 1 is the application principle block diagram of existing current foldback circuit;
Fig. 2 is the circuit theory composition frame chart of existing current foldback circuit;
Fig. 3 is the main composition structured flowchart of current foldback circuit of the present invention;
Fig. 4 forms structured flowchart for a kind of embodiment of current foldback circuit of the present invention;
Fig. 5 is the application principle block diagram of current foldback circuit of the present invention.
Embodiment
Design aim of the present invention provides a kind of different overcurrent threshold values that can bear according to different loads; by software flexible control adjust in requisition for the current foldback circuit of reference voltage level, to be applicable to because the frequent transformation load of needs causes taking the application scenario of normal modification overcurrent threshold values.
Be explained in detail below in conjunction with the specific implementation process of each accompanying drawing current foldback circuit of the present invention; please refer to Fig. 3; this figure is the main composition structured flowchart of current foldback circuit of the present invention; its chief component comprises current sampling circuit 101, voltage comparator 102, control unit 1031 and 1,032 four parts of voltage follower circuit, the concrete function of each part and act on as follows:
Please refer to Fig. 4, this figure is that a kind of embodiment of current foldback circuit of the present invention is formed structured flowchart, and wherein the concrete composition structure of this execution mode is as follows:
Digital to analog converter DAC 1033, its control port access control unit 1031, output port connects "-" utmost point of voltage comparator 102, and this DAC 1033 is controlled by the reference voltage level of output control unit 1031 indicated outputs.
Reference voltage level computation subunit 1035, be mainly used in overcurrent threshold values I that load that current sampling circuit 101 is connected can bear and the resistance value R that is connected on power output end and multiply each other, to obtain reference voltage level U the overcurrent threshold values I that should load can bear;
To sum up, just can realize exporting the corresponding reference magnitudes of voltage according to the different DAC of control flexibly 1033 that current sampling circuit 101 connects load, to realize being provided with flexibly the purpose of different reference voltage levels according to the unequally loaded situation by the software in the system control cpu.Wherein the degree of regulation of reference voltage level and DAC choose relevant.
See also Fig. 5; this figure is the application principle block diagram of current foldback circuit of the present invention; current foldback circuit of the present invention as shown in the figure can be according to connecting different loading conditions; realize being provided with flexibly the reference voltage level of the overcurrent threshold values that corresponding different loads can bear by the software that is provided with in the system control cpu; can play overcurrent protection preferably to the circuit that often needs transformation load, when guaranteeing that different loads can not be higher than the overcurrent threshold values that load can bear because of the electric current of flowing through and be damaged.Current foldback circuit wherein of the present invention can be applied on the equipment such as various power supplys, instrument; and the overcurrent threshold values that can bear according to different loads is provided with different reference voltage levels; and need not revise any circuit hardware, only need can realize by software setting.
Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.
Claims (4)
1, a kind of current foldback circuit is characterized in that, comprising:
The current sampling circuit that connects power supply and load respectively is used for the electric current of the load of flowing through is sampled, and the sample voltage value of output sample rate current;
Control unit is used for determining reference voltage level according to the overcurrent threshold values that the load that current sampling circuit connects can bear;
The voltage follower circuit that is connected with control unit is used for the reference voltage level output that control unit is determined; With
Voltage comparator is used for the sample voltage value of current sampling circuit output and the reference voltage level of voltage follower circuit output are compared, and when sample voltage value is higher than reference voltage level, output overcurrent index signal indication mains switch power cutoff.
2, current foldback circuit as claimed in claim 1 is characterized in that, described current sampling circuit is the resistance that is connected on power output end.
3, current foldback circuit as claimed in claim 2 is characterized in that, described control unit specifically comprises:
The reference voltage level computation subunit is used for overcurrent threshold values that the load that current sampling circuit connects be can bear and the resistance value that is connected on power output end and multiplies each other, and obtains described reference voltage level;
The indication subelement is used to the reference voltage level output of indicating voltage follower circuit that the reference voltage level computation subunit is calculated.
As claim 1,2 or 3 described current foldback circuits, it is characterized in that 4, described voltage follower circuit is a digital to analog converter; The control port of described digital to analog converter is connected with control unit, and output port is used for the output reference voltage value.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
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CNB2005100768534A CN100420113C (en) | 2005-06-17 | 2005-06-17 | Overcurrent protection circuit |
Applications Claiming Priority (1)
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CNB2005100768534A CN100420113C (en) | 2005-06-17 | 2005-06-17 | Overcurrent protection circuit |
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CN1848577A true CN1848577A (en) | 2006-10-18 |
CN100420113C CN100420113C (en) | 2008-09-17 |
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CNB2005100768534A Expired - Fee Related CN100420113C (en) | 2005-06-17 | 2005-06-17 | Overcurrent protection circuit |
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Cited By (24)
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WO2010083753A1 (en) * | 2009-01-21 | 2010-07-29 | 成都芯源系统有限公司 | Circuit and method for providing power supply voltage for wireless network card |
CN101860001A (en) * | 2010-05-06 | 2010-10-13 | 北京鼎汉技术股份有限公司 | Switch power supply current detection circuit |
CN101931206A (en) * | 2010-08-25 | 2010-12-29 | 常熟开关制造有限公司(原常熟开关厂) | Over-current protection method |
CN101976814A (en) * | 2010-10-30 | 2011-02-16 | 珠海市鑫和电器有限公司 | Medical power supply management circuit |
CN101499646B (en) * | 2008-06-10 | 2011-05-18 | 上海英联电子系统有限公司 | Automatically temperature compensating average value over-current protection circuit |
CN102487187A (en) * | 2012-01-06 | 2012-06-06 | 厦门华侨电子股份有限公司 | Power supply detection and control circuit |
CN102545143A (en) * | 2010-12-13 | 2012-07-04 | 华为技术有限公司 | Device and method for detection and protection and circuit board |
CN102798791A (en) * | 2011-05-26 | 2012-11-28 | 通用电气公司 | Systems and methods for determining electrical faults |
CN102858049A (en) * | 2011-06-30 | 2013-01-02 | 海洋王照明科技股份有限公司 | Over-current protection sampling circuit, light-emitting diode (LED) drive circuit and LED lamp |
CN102916387A (en) * | 2012-10-31 | 2013-02-06 | 深圳市虹远通信有限责任公司 | Protection circuit for multi-port POE (power over Ethernet) power supply output shunt |
CN103219694A (en) * | 2013-04-17 | 2013-07-24 | 宁波汉浦工具有限公司 | Over-current protecting circuit |
CN103259245A (en) * | 2012-02-17 | 2013-08-21 | 台达电子工业股份有限公司 | Protective circuit and protective method of electronic device |
WO2013189197A1 (en) * | 2012-06-19 | 2013-12-27 | 华为技术有限公司 | Protection circuit, control method therefor, and telecommunication subrack equipment |
CN104810783A (en) * | 2014-01-27 | 2015-07-29 | Ls产电株式会社 | Analog current output module |
US9541604B2 (en) | 2013-04-29 | 2017-01-10 | Ge Intelligent Platforms, Inc. | Loop powered isolated contact input circuit and method for operating the same |
CN106532635A (en) * | 2016-11-11 | 2017-03-22 | 索尔思光电(成都)有限公司 | Apd protection circuit |
CN106597063A (en) * | 2017-01-25 | 2017-04-26 | 杭州士兰微电子股份有限公司 | Current detecting circuit and current detecting method |
WO2018058999A1 (en) * | 2016-09-28 | 2018-04-05 | 华为技术有限公司 | Overcurrent point configuration method and apparatus, and overcurrent protection apparatus |
CN109017631A (en) * | 2018-06-27 | 2018-12-18 | 联合汽车电子有限公司 | The sensor ground protection circuit of Vehicle Controller |
CN109038476A (en) * | 2018-08-08 | 2018-12-18 | 杭州先途电子有限公司 | A kind of current foldback circuit and controller |
CN111082677A (en) * | 2019-12-30 | 2020-04-28 | 杭州士兰微电子股份有限公司 | Switching power supply and control circuit and control method thereof |
CN111181370A (en) * | 2019-12-30 | 2020-05-19 | 杭州士兰微电子股份有限公司 | Switching power supply and control circuit and control method thereof |
CN113508506A (en) * | 2020-12-31 | 2021-10-15 | 华为技术有限公司 | Photovoltaic power generation system, photovoltaic inverter and direct current collection flow box |
CN114076904A (en) * | 2020-08-19 | 2022-02-22 | 深圳市理邦精密仪器股份有限公司 | Protection circuit, electrical stimulation device and protection method |
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US5546265A (en) * | 1994-05-20 | 1996-08-13 | General Electric Company | Digital circuit interrupter shunt trip control circuit |
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CN1248352C (en) * | 2003-06-06 | 2006-03-29 | 比亚迪股份有限公司 | Adjuster for lithium cell protective circuit protective threshold value |
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CN101499646B (en) * | 2008-06-10 | 2011-05-18 | 上海英联电子系统有限公司 | Automatically temperature compensating average value over-current protection circuit |
WO2010083753A1 (en) * | 2009-01-21 | 2010-07-29 | 成都芯源系统有限公司 | Circuit and method for providing power supply voltage for wireless network card |
CN101860001A (en) * | 2010-05-06 | 2010-10-13 | 北京鼎汉技术股份有限公司 | Switch power supply current detection circuit |
CN101860001B (en) * | 2010-05-06 | 2012-11-28 | 北京鼎汉技术股份有限公司 | Switch power supply current detection circuit |
CN101931206B (en) * | 2010-08-25 | 2013-04-03 | 常熟开关制造有限公司(原常熟开关厂) | Over-current protection method |
CN101931206A (en) * | 2010-08-25 | 2010-12-29 | 常熟开关制造有限公司(原常熟开关厂) | Over-current protection method |
CN101976814A (en) * | 2010-10-30 | 2011-02-16 | 珠海市鑫和电器有限公司 | Medical power supply management circuit |
CN101976814B (en) * | 2010-10-30 | 2012-12-12 | 珠海市鑫和电器有限公司 | Medical power supply management circuit |
CN102545143A (en) * | 2010-12-13 | 2012-07-04 | 华为技术有限公司 | Device and method for detection and protection and circuit board |
CN102798791B (en) * | 2011-05-26 | 2018-01-09 | 通用电气公司 | System and method for determining electric fault |
CN102798791A (en) * | 2011-05-26 | 2012-11-28 | 通用电气公司 | Systems and methods for determining electrical faults |
CN102858049B (en) * | 2011-06-30 | 2015-02-18 | 海洋王照明科技股份有限公司 | Over-current protection sampling circuit, light-emitting diode (LED) drive circuit and LED lamp |
CN102858049A (en) * | 2011-06-30 | 2013-01-02 | 海洋王照明科技股份有限公司 | Over-current protection sampling circuit, light-emitting diode (LED) drive circuit and LED lamp |
CN102487187A (en) * | 2012-01-06 | 2012-06-06 | 厦门华侨电子股份有限公司 | Power supply detection and control circuit |
CN103259245A (en) * | 2012-02-17 | 2013-08-21 | 台达电子工业股份有限公司 | Protective circuit and protective method of electronic device |
CN103259245B (en) * | 2012-02-17 | 2015-10-28 | 台达电子工业股份有限公司 | The protective circuit of electronic installation and guard method |
WO2013189197A1 (en) * | 2012-06-19 | 2013-12-27 | 华为技术有限公司 | Protection circuit, control method therefor, and telecommunication subrack equipment |
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CN103219694A (en) * | 2013-04-17 | 2013-07-24 | 宁波汉浦工具有限公司 | Over-current protecting circuit |
CN103219694B (en) * | 2013-04-17 | 2015-09-23 | 宁波汉浦工具有限公司 | Current foldback circuit |
US9541604B2 (en) | 2013-04-29 | 2017-01-10 | Ge Intelligent Platforms, Inc. | Loop powered isolated contact input circuit and method for operating the same |
CN104810783B (en) * | 2014-01-27 | 2019-03-05 | Ls产电株式会社 | Analog current output module |
CN104810783A (en) * | 2014-01-27 | 2015-07-29 | Ls产电株式会社 | Analog current output module |
WO2018058999A1 (en) * | 2016-09-28 | 2018-04-05 | 华为技术有限公司 | Overcurrent point configuration method and apparatus, and overcurrent protection apparatus |
CN106532635A (en) * | 2016-11-11 | 2017-03-22 | 索尔思光电(成都)有限公司 | Apd protection circuit |
CN106597063A (en) * | 2017-01-25 | 2017-04-26 | 杭州士兰微电子股份有限公司 | Current detecting circuit and current detecting method |
CN109017631A (en) * | 2018-06-27 | 2018-12-18 | 联合汽车电子有限公司 | The sensor ground protection circuit of Vehicle Controller |
CN109038476A (en) * | 2018-08-08 | 2018-12-18 | 杭州先途电子有限公司 | A kind of current foldback circuit and controller |
CN111082677A (en) * | 2019-12-30 | 2020-04-28 | 杭州士兰微电子股份有限公司 | Switching power supply and control circuit and control method thereof |
CN111181370A (en) * | 2019-12-30 | 2020-05-19 | 杭州士兰微电子股份有限公司 | Switching power supply and control circuit and control method thereof |
CN111082677B (en) * | 2019-12-30 | 2022-03-15 | 杭州士兰微电子股份有限公司 | Switching power supply and control circuit and control method thereof |
CN114076904A (en) * | 2020-08-19 | 2022-02-22 | 深圳市理邦精密仪器股份有限公司 | Protection circuit, electrical stimulation device and protection method |
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