CN101309004A - Overcurrent protection circuit - Google Patents
Overcurrent protection circuit Download PDFInfo
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- CN101309004A CN101309004A CNA2008100648625A CN200810064862A CN101309004A CN 101309004 A CN101309004 A CN 101309004A CN A2008100648625 A CNA2008100648625 A CN A2008100648625A CN 200810064862 A CN200810064862 A CN 200810064862A CN 101309004 A CN101309004 A CN 101309004A
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Abstract
The invention discloses an over current protection circuit which includes a current detecting circuit, a voltage threshold judging circuit, a delay circuit, a triggering and recovering circuit and a protection push circuit. The current detecting circuit is connected with the voltage threshold judging circuit which is connected with the delay circuit; the delay circuit is connected with the triggering and recovering circuit which is connected with the protection push circuit; and the protection push circuit is connected with the device or equipment being protected. In the real working, the over current protection circuit of the invention can avoid the misoperation of the protection circuit due to the interference by the working circuit, especially the sharp peak current interference, or by the instant current sharp peak generated in the instant startup of the equipment. The action process of the invention is convenient, safe and reliable, and can ensure the equipment to work normally under the existence of current sharp peak interference and instant startup of the equipment.
Description
(1) technical field
The present invention relates to a kind of electronic circuit technology, be specifically related to the protective circuit of overcurrent in a kind of electric installation.
(2) technical background
In electric equipment, some devices or equipment, when electric current during greater than certain numerical value, may cause device or equipment burn or can't operate as normal, so need carry out the protection of overcurrent to these devices or equipment.In real work, on the one hand when load is zero, output short-circuit fault for example, transistor has suitable electric current to flow through, and the voltage that this moment, transistor bore is very big, thereby the power that causes transistor to bear has surpassed the maximum power that transistor can bear, cause transistor to burn, as the high power third-level pipe, high-power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), IGBT (insulated gate bipolar transistor) etc. are as the transistor of voltage-regulation, because these transistor prices are relatively costly, during design, as maximum permissible current, the current value that flows through with to common action the time has enough surpluses and designs.Because transistorized damage, not only influence the operate as normal of electric installation, also may cause damaging other device or equipment, cause bigger economic loss; On the other hand,, but, there is the situation of carrying out the electric current restriction, as equipment such as motors, because fault causes the excessive coil burnout that causes of electric current easily for protection device or equipment even below the transistorized maximum current that can bear.
Therefore, avoided overcurrent for protective transistor, or in order to limit the electric current that flows through in the load equipment, setting has the protective circuit of current limit function in electric equipment in the past.
But in real work, because the especially spike interference of electric current of the interference of operating circuit, or equipment moment startup causes reasons such as immediate current spike, may cause the misoperation of protective circuit.
(3) summary of the invention
The object of the present invention is to provide a kind of convenience, safety, reliable, when current spike interference and equipment moment startup are arranged, the current foldback circuit of energy operate as normal.
The object of the present invention is achieved like this: it comprises that current detection circuit 1, voltage threshold judging circuit 2, delay circuit 3, triggering and restore circuit 4 and protection promote circuit 5; Current detection circuit 1 links to each other with voltage threshold judging circuit 2; Voltage threshold judging circuit 2 links to each other with delay circuit 3; Delay circuit 3 links to each other with restore circuit 4 with triggering; Trigger with restore circuit 4 and protection promotion circuit 5 and link to each other; Protection promotes circuit 5 and is connected with the device or the equipment of protection.
The present invention also has some technical characterictics like this:
1, described current detection circuit 1 be current transformer or electric current to voltage changer, output is connected with the input of voltage threshold judging circuit 2;
2, described voltage threshold judging circuit 2 comprises reference voltage Vref and voltage comparator U1, the output of current detection circuit 1 links to each other with the first input end of voltage comparator U1, the second input termination reference voltage Vref of voltage comparator U1, the output of voltage comparator U1 links to each other with the input of delay circuit 3;
3, described delay circuit 3 comprises resistance R 1 and resistance R 2, triode Q and capacitor C 1, and the output of the voltage comparator U1 of voltage threshold judging circuit 2 links to each other with an end of the resistance R 1 of delay circuit 3 and the base stage of triode Q; Another termination positive source of resistance R 1; The emitter of triode Q connects positive source; One termination power positive pole of capacitor C 1, the collector electrode of the other end of capacitor C 1, triode Q, an end of resistance R 2 link to each other with restore circuit 4 with triggering; The other end of resistance R 2 links to each other with power supply ground;
4, described triggering and restore circuit 4 are become by 555 o'clock basis set that device U2, light-emitting diode D1, resistance R 4 and R3, capacitor C 2 and C3, hilted broadsword are two to be put button and constitute, and an end of the other end of the capacitor C 1 of delay circuit 3, the collector electrode of triode Q, resistance R 2 becomes 2 pin of device U2 to link to each other with 555 o'clock basis sets; Basis set became 8 pin of device U2 to link to each other with positive source with 4 pin in 555 o'clock, and 1 pin links to each other with power supply ground; One end of capacitor C 2 becomes 5 pin of device U2 to link to each other with 555 o'clock basis sets, and the other end links to each other with power supply ground; One end of resistance R 4 becomes 3 pin of device U2 to link to each other with 555 o'clock basis sets, and the other end links to each other with the positive pole of light-emitting diode D1; The negative level of light-emitting diode D1 links to each other with power supply ground; Basis set became 6 pin of device U2 to link to each other with an end of resistance R 3, an end of capacitor C 3 in 555 o'clock; The other end of resistance R 3 links to each other with power supply ground; The other end of capacitor C 3 links to each other with the two common ports of putting button S1 of hilted broadsword; The two ends of putting button S1 of hilted broadsword link to each other with power supply ground, and the other end links to each other with positive source; Basis set became 7 pin of device U2 to promote linking to each other of circuit 5 with protection in 555 o'clock;
5, described protection promotion circuit 5 is made up of relay K and resistance R 5, and basis set became 7 pin of device U2 to link to each other with an end of the control end of relay K in 555 o'clock; One end of resistance R 5 links to each other with the other end of the control end of relay K, and the other end links to each other with positive source; One end of the output normal-closed end of relay K and the other end insert the device of protection or the current path that equipment flows through respectively.
When current foldback circuit of the present invention work, the voltage signal of current detection circuit 1 output with flow through the device that needs protection or the electric current of equipment and have certain corresponding relation, and voltage signal is inputed to voltage threshold judging circuit 2.Voltage threshold judging circuit 2 judges according to the voltage signal of input and flows through the device that needs protection or whether the electric current of equipment surpasses certain size of current that if surpass certain size of current, then the output overcurrent signal is given delay circuit 3.The output signal of 3 pairs of voltage threshold judging circuits 2 of delay circuit plays delayed action, the action time of delay of circuit in the time of can adjusting overcurrent by the parameter of respective element in the apolegamy circuit.Delay circuit 3 is through the delay of certain hour; trigger and restore circuit 4 is accepted the overcurrent actuating signal and drive protection to promote circuit 5 and block and flow through the device that needs protection or the electric current of equipment; triggering and restore circuit 4 also provide resetting means simultaneously; if restore circuit work; the artificial button that promotes in triggering and the restore circuit 4 recovers device or equipment work.
The present invention can be in real work; can avoid because the especially spike interference of electric current of the interference of operating circuit; or equipment moment starts the protective circuit misoperation that reasons such as causing the immediate current spike causes; mechanism of the present invention is convenient, safety, reliable, can guarantee the equipment operate as normal when current spike interference and equipment moment startup are arranged.
(4) description of drawings
Fig. 1 is the schematic diagram of the execution mode of current foldback circuit of the present invention.
(5) embodiment
The invention will be further described below in conjunction with accompanying drawing.
In conjunction with Fig. 1; the voltage that the current foldback circuit of present embodiment comprises its output of being made up of current transformer and the electric current that flows through the device that needs protection or equipment have linear ratio relation's current detection circuit 1; the voltage threshold judging circuit of forming by reference voltage Vref and voltage comparator U1 2; by resistance R 1 and R2; the delay circuit 3 that triode Q and capacitor C 1 are formed; become device by 555 o'clock basis set; light-emitting diode D1; resistance R 4 and R3; capacitor C 2 and C3; the protection promotion circuit 5 that hilted broadsword is two to be put triggering that button constitutes and restore circuit 4 and is made up of relay.The current transformer output of current detection circuit 1 links to each other with the first input end of the voltage comparator U1 of voltage threshold judging circuit 2, the second input termination reference voltage Vref of the voltage comparator U1 of voltage threshold judging circuit 2; The output of the voltage comparator U1 of voltage threshold judging circuit 2 links to each other with an end of the resistance R 1 of delay circuit 3 and the base stage of triode Q; Another termination positive source of the resistance R 1 of delay circuit 3; The emitter of the triode Q of delay circuit 3 connects positive source; One termination power positive pole of the capacitor C 1 of delay circuit 3; One end of the collector electrode of the other end of the capacitor C 1 of delay circuit 3, the triode Q of delay circuit 3, the resistance R 2 of delay circuit 3 becomes 2 pin of device U2 to link to each other with 555 o'clock basis sets of triggering and restore circuit 4; The other end of the resistance R 2 of delay circuit 3 links to each other with power supply ground; Trigger with restore circuit 4 in 555 o'clock basis sets become 8 pin of device U2 to link to each other with positive source with 4 pin; Triggering becomes 1 pin of device U2 to link to each other with power supply ground with 555 o'clock basis sets of restore circuit 4; One end of the capacitor C 2 of triggering and restore circuit 4 becomes 5 pin of device U2 to link to each other with 555 o'clock basis sets of triggering and restore circuit 4, and the other end links to each other with power supply ground; One end of the resistance R 4 of triggering and restore circuit 4 becomes 3 pin of device U2 to link to each other with 555 o'clock basis sets of triggering and restore circuit 4, and the other end links to each other with the positive pole of the light-emitting diode D1 of triggering and restore circuit 4; The negative level of the light-emitting diode D1 of triggering and restore circuit 4 links to each other with power supply ground; Triggering becomes 6 pin of device U2 to link to each other with an end of the capacitor C 3 of an end, triggering and the restore circuit 4 of the resistance R 3 of triggering and restore circuit 4 with 555 o'clock basis sets of restore circuit 4; The other end of the resistance R 3 of triggering and restore circuit 4 links to each other with power supply ground; The other end of the capacitor C 3 of triggering and restore circuit 4 links to each other with the two common ports of putting button S1 of the hilted broadsword of triggering and restore circuit 4; The two ends of putting button S1 of the hilted broadsword of triggering and restore circuit 4 link to each other with power supply ground, and the other end links to each other with positive source; Triggering with 555 o'clock basis sets of restore circuit 4 becomes 7 pin of device U2 to link to each other with an end of the control end of the relay K of protection promotion circuit 5; The end that protection promotes the resistance R 5 of circuit 5 links to each other with the other end of the control end of the relay K of protection promotion circuit 5, and the other end links to each other with positive source; One end and the device that the other end inserts protection respectively or the current path that equipment flows through of the output normal-closed end of the relay K of protection promotion circuit 5.
When the overcurrent protective circuit is worked; the current transformer induced flow overprotection device of current detection circuit 1 or the electric current of equipment; concern output voltage signal by a certain percentage, and voltage signal is inputed to the inverting input of the comparator U1 of voltage threshold judging circuit 2.The comparator U1 of voltage threshold judging circuit 2 compares according to the voltage signal of input and the reference voltage Vref of in-phase input end; if greater than reference voltage Vref; then comparator U1 output is a voltage near positive source by the voltage transformation near power supply ground; judge and to flow through the device that needs protection or the electric current of equipment has surpassed the setting size of current, then the output overcurrent signal is given delay circuit 3.Delay circuit 3 triggers and restore circuit 4 through the delay of certain hour.Trigger and restore circuit 4 drives protection and promotes circuit 5 and block and flow through the device that needs protection or the electric current of equipment.If restore circuit work, the artificial button that promotes in triggering and the restore circuit 4 recovers device or equipment work.
Its time of delay is by the value decision of resistance and electric capacity.
Claims (6)
1. current foldback circuit, it is characterized in that it comprises that current detection circuit (1), voltage threshold judging circuit (2), delay circuit (3), triggering and restore circuit (4) and protection promote circuit (5), current detection circuit (1) links to each other with voltage threshold judging circuit (2), and voltage threshold judging circuit (2) links to each other with delay circuit (3); Delay circuit (3) links to each other with restore circuit (4) with triggering; Trigger with restore circuit (4) and protection promotion circuit (5) and link to each other; Protection promotes circuit (5) and is connected with the device or the equipment of protection.
2. a kind of current foldback circuit according to claim 1, it is characterized in that described current detection circuit (1) for current transformer or electric current to voltage changer, output is connected with the input of voltage threshold judging circuit (2).
3. a kind of current foldback circuit according to claim 2; it is characterized in that described voltage threshold judging circuit (2) comprises reference voltage Vref and voltage comparator U1; the output of current detection circuit (1) links to each other with the first input end of voltage comparator U1; the second input termination reference voltage Vref of voltage comparator U1, the output of voltage comparator U1 links to each other with the input of delay circuit (3).
4. a kind of current foldback circuit according to claim 3, it is characterized in that described delay circuit (3) comprises resistance R 1 and resistance R 2, triode Q and capacitor C 1, the output of the voltage comparator U1 of voltage threshold judging circuit (2) links to each other with an end of the resistance R 1 of delay circuit (3) and the base stage of triode Q; Another termination positive source of resistance R 1; The emitter of triode Q connects positive source; One termination power positive pole of capacitor C 1, the collector electrode of the other end of capacitor C 1, triode Q, an end of resistance R 2 link to each other with restore circuit (4) with triggering; The other end of resistance R 2 links to each other with power supply ground.
5. a kind of current foldback circuit according to claim 4, it is characterized in that described triggering and restore circuit (4) are become by 555 o'clock basis set that device U2, light-emitting diode D1, resistance R 4 and R3, capacitor C 2 and C3, hilted broadsword are two to be put button and constitute, an end of the other end of the capacitor C 1 of delay circuit (3), the collector electrode of triode Q, resistance R 2 becomes 2 pin of device U2 to link to each other with 555 o'clock basis sets; Basis set became 8 pin of device U2 to link to each other with positive source with 4 pin in 555 o'clock, and 1 pin links to each other with power supply ground; One end of capacitor C 2 becomes 5 pin of device U2 to link to each other with 555 o'clock basis sets, and the other end links to each other with power supply ground; One end of resistance R 4 becomes 3 pin of device U2 to link to each other with 555 o'clock basis sets, and the other end links to each other with the positive pole of light-emitting diode D1; The negative level of light-emitting diode D1 links to each other with power supply ground; Basis set became 6 pin of device U2 to link to each other with an end of resistance R 3, an end of capacitor C 3 in 555 o'clock; The other end of resistance R 3 links to each other with power supply ground; The other end of capacitor C 3 links to each other with the two common ports of putting button S1 of hilted broadsword; The two ends of putting button S1 of hilted broadsword link to each other with power supply ground, and the other end links to each other with positive source; Basis set became 7 pin of device U2 to promote linking to each other of circuit (5) with protection in 555 o'clock.
6. a kind of current foldback circuit according to claim 5 is characterized in that described protection promotes circuit (5) and is made up of relay K and resistance R 5, and basis set became 7 pin of device U2 to link to each other with an end of the control end of relay K in 555 o'clock; One end of resistance R 5 links to each other with the other end of the control end of relay K, and the other end links to each other with positive source; One end of the output normal-closed end of relay K and the other end insert the device of protection or the current path that equipment flows through respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100648625A CN101309004A (en) | 2008-07-07 | 2008-07-07 | Overcurrent protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100648625A CN101309004A (en) | 2008-07-07 | 2008-07-07 | Overcurrent protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101309004A true CN101309004A (en) | 2008-11-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2008100648625A Pending CN101309004A (en) | 2008-07-07 | 2008-07-07 | Overcurrent protection circuit |
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| Country | Link |
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| CN (1) | CN101309004A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102496903A (en) * | 2011-11-15 | 2012-06-13 | 深圳桑达国际电子器件有限公司 | Over-current protection circuit, power supply circuit and power supply |
| CN103269055A (en) * | 2013-06-05 | 2013-08-28 | 上海电机学院 | Relay protection device and method |
| CN103269056A (en) * | 2013-06-08 | 2013-08-28 | 临沂市拓普网络股份有限公司 | Current detection protection device and method |
| CN107843890A (en) * | 2017-10-31 | 2018-03-27 | 海鹰企业集团有限责任公司 | Sonar transmission circuit |
| CN110718894A (en) * | 2018-07-12 | 2020-01-21 | 西门子股份公司 | Low-voltage circuit breaker and method |
| CN114465198A (en) * | 2022-03-10 | 2022-05-10 | 陕西瑞禾景明科技有限公司 | Abnormal current control circuit and control method of geophone |
-
2008
- 2008-07-07 CN CNA2008100648625A patent/CN101309004A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102496903A (en) * | 2011-11-15 | 2012-06-13 | 深圳桑达国际电子器件有限公司 | Over-current protection circuit, power supply circuit and power supply |
| CN102496903B (en) * | 2011-11-15 | 2014-10-29 | 深圳桑达国际电子器件有限公司 | Over-current protection circuit, power supply circuit and power supply |
| CN103269055A (en) * | 2013-06-05 | 2013-08-28 | 上海电机学院 | Relay protection device and method |
| CN103269055B (en) * | 2013-06-05 | 2016-09-28 | 上海电机学院 | Protective relaying device and method |
| CN103269056A (en) * | 2013-06-08 | 2013-08-28 | 临沂市拓普网络股份有限公司 | Current detection protection device and method |
| CN103269056B (en) * | 2013-06-08 | 2015-06-17 | 临沂市拓普网络股份有限公司 | Current detection protection device and method |
| CN107843890A (en) * | 2017-10-31 | 2018-03-27 | 海鹰企业集团有限责任公司 | Sonar transmission circuit |
| CN110718894A (en) * | 2018-07-12 | 2020-01-21 | 西门子股份公司 | Low-voltage circuit breaker and method |
| US11152778B2 (en) | 2018-07-12 | 2021-10-19 | Siemens Aktiengesellschaft | Low-voltage circuit breaker and method |
| CN110718894B (en) * | 2018-07-12 | 2022-05-24 | 西门子股份公司 | Low-voltage circuit breaker and method |
| CN114465198A (en) * | 2022-03-10 | 2022-05-10 | 陕西瑞禾景明科技有限公司 | Abnormal current control circuit and control method of geophone |
| CN114465198B (en) * | 2022-03-10 | 2023-01-24 | 陕西瑞禾景明科技有限公司 | Abnormal current control circuit and control method of geophone |
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| PB01 | Publication | ||
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Open date: 20081119 |