CN103049029A - Current-limiting circuit - Google Patents
Current-limiting circuit Download PDFInfo
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- CN103049029A CN103049029A CN2012105845861A CN201210584586A CN103049029A CN 103049029 A CN103049029 A CN 103049029A CN 2012105845861 A CN2012105845861 A CN 2012105845861A CN 201210584586 A CN201210584586 A CN 201210584586A CN 103049029 A CN103049029 A CN 103049029A
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- triode
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Abstract
The invention relates to a current-limiting circuit. The current-limiting circuit comprises sampling resistors, a filtering capacitor, a current-limiting triode, a control triode and a control switch triode, wherein the filtering capacitor is connected with an output end. A base electrode of the current-limiting triode is connected with a collector electrode of the control triode, an emitting electrode of the current-limiting triode is connected with a power circuit output end, and a collector electrode of the current-limiting triode is connected with the output end. A base electrode of the control triode is connected with the power circuit output end, and an emitting electrode of the control triode is connected with a +12V power supply. The sampling resistors are connected between the power circuit output end and the +12V power supply, an emitting electrode of the control switch triode is grounded, a base electrode of the control switch triode is connected with an enable signal end, a current-limiting resistor is serially connected between the base electrode of the control switch triode and the enable signal end, a collector electrode of the control switch triode is connected with the base electrode of the current-limiting triode, a voltage-dividing resistor is serially connected between the collector electrode of the control switch triode and the base electrode of the current-limiting triode, the collector electrode of the control triode is connected with the +12V power supply, and a voltage-dividing resistor is serially connected between the collector electrode of the control triode and the +12V power supply. A current-limiting value of the current-limiting circuit does not fluctuate along with change of voltage and is high in precision. Besides, the current-limiting circuit has the negative temperature coefficient characteristic, the current-limiting value is decreased along with temperature increase of the circuit, and accordingly electric energy is saved.
Description
Technical field
The present invention relates to a kind of current-limiting circuit, specifically a kind of current-limiting circuit for low-voltage power line carrier communication module.
Background technology
Present known existing current-limiting circuit, circuit structure is complicated, and circuit component is numerous, and production cost is higher, and has positive temperature coefficient (PTC), and the cut-off current precision is low.
Current-limiting circuit in the carrier module as shown in Figure 1, current-limiting circuit effect be the restriction carrier module right+maximum current consumption of 12V, if the current amplification factor H of triode
FE=300, the restriction output current should be no more than 156mA, and after circuit entered current-limit mode, triode V3 can generate heat, and temperature raises, and causes the current amplification factor H of triode
FEIncrease, thereby make output current become large, the temperature of triode V3 continues to raise, and continues to make output current to become large, has formed positive feedback, does not reach good current limitation effect.Current-limiting circuit also is subject to the impact of supply voltage, and when supply voltage raise, cut-off current increased, and when supply voltage reduced, cut-off current reduced, and cut-off current is unstable.And the current amplification factor H of triode
FEDegree of accuracy lower, precision that also can first cut-off current.
Summary of the invention
The present invention is directed to existing current-limiting circuit complex structure, the problem such as circuit component is numerous, and production cost is higher, and has positive temperature coefficient (PTC), and the cut-off current precision is low has designed a kind of current-limiting circuit.
A kind of current-limiting circuit of the present invention comprises two current sampling resistors in parallel, the filter capacitor that links to each other with output terminal, current limliting triode, control triode, gauge tap triode, filter capacitor ground connection; The base stage of current limliting triode is connected with the collector of control triode; The collector of current limliting triode is connected with output terminal; The emitter of current limliting triode is connected with power circuit output end; The base stage of control triode links to each other with power circuit output end; The emitter of control triode is connected with+12V power supply; Two in parallel current sampling resistors be connected to power circuit output end and+the 12V power supply between; The grounded emitter of gauge tap triode; The base stage of gauge tap triode is connected with the enable signal end, is connected with current-limiting resistance therebetween; The collector of gauge tap triode links to each other with the base stage of current limliting triode, is in series with divider resistance therebetween; The collector of control triode is connected with+12V power supply, is connected with divider resistance therebetween.
Preferably, current limliting triode and control triode are the positive-negative-positive triode, and the gauge tap triode is NPN type triode.
Preferably, base stage and the power circuit output end of control triode also are connected with divider resistance therebetween.
Preferably, be connected with buffer resistance between power circuit output end and the output terminal.
The invention has the beneficial effects as follows: the cut-off current of current-limiting circuit does not fluctuate with the variation of voltage, the cut-off current precision is higher, current-limiting circuit has the characteristic of negative temperature coefficient, rising along with circuit temperature, cut-off current reduces, can save electric energy, circuit can not damaged because of overheated, improve the reliability of circuit.
Description of drawings
Accompanying drawing 1 is the circuit theory diagrams of existing current-limiting circuit.
Accompanying drawing 2 is the circuit theory diagrams of current-limiting circuit of the present invention.
Accompanying drawing 3 is the structured flowchart of current-limiting circuit of the present invention.
Embodiment
A kind of current-limiting circuit of the present invention, shown in Fig. 2 to 3, comprise two current sampling resistor R38, R39 in parallel, the filter capacitor C26 that links to each other with output terminal, current limliting triode Q7, control triode Q8, gauge tap triode Q9, current limliting triode Q7 and control triode Q8 are the positive-negative-positive triode, and gauge tap triode Q9 is NPN type triode.
Filter capacitor C26 ground connection; The base stage of current limliting triode Q7 is connected with the collector of control triode Q8; The collector of current limliting triode Q7 is connected with output terminal; The emitter of current limliting triode Q7 is connected with power circuit output end VCC; The base stage of control triode Q8 links to each other with power circuit output end VCC, also is connected with divider resistance R37 therebetween; The emitter of control triode Q8 is connected with+12V power supply; Two in parallel current sampling resistor R38, R39 be connected to power circuit output end VCC and+the 12V power supply between; The grounded emitter of gauge tap triode Q9; The base stage of gauge tap triode Q9 is connected with the enable signal end, is connected with current-limiting resistance R42 therebetween; The collector of gauge tap triode Q9 links to each other with the base stage of current limliting triode Q7, is in series with divider resistance R40 therebetween; The collector of control triode Q8 is connected with+12V power supply, is connected with divider resistance R41 therebetween; Be connected with buffer resistance R36 between power circuit output end VCC and the output terminal.
When the voltage at current sampling resistor R38 and R39 two ends is higher than 0.6V, control triode Q8 conducting, the collector C of control triode Q8 and the voltage between the emitter E can be reduced to about 0.3V, divider resistance R37 is the less resistance of resistance, when the collector C of control triode Q8 and the voltage between the emitter E can be reduced to 0.3V, the collector B of current limliting triode Q7 and the voltage between the emitter E is the approximate 0.3V that reduces to also, this moment, current limliting triode Q7 turn-offed, and the emitter current of current limliting triode Q7 stops.
When current-limiting resistance R42 did not work, gauge tap triode Q9 blocked the electric current of divider resistance R40 and R41, reduced quiescent dissipation, had reached energy-conservation purpose.
Divider resistance R40 and R41 provide base voltage for current limliting triode Q7, when the voltage drop of+12V power supply, and the base stage of current limliting triode Q7 and the voltage U between the emitter
BeAlso can reduce, when the base stage of current limliting triode Q7 and the voltage U between the emitter
BeWhen being lower than 0.6V, current limliting triode Q7 turn-offs, and the emitter current of current limliting triode Q7 stops, and has reached the purpose of under-voltage protection.
When current-limiting circuit enters current-limit mode, the temperature of current limliting triode Q7 rises, control triode Q8 also can receive the heat that current limliting triode Q7 passes over raises its temperature, after the temperature of current limliting triode Q7 and control triode Q8 raises, its separately base stage and the voltage U between the emitter
BeReduce, cut-off current reduces, and makes current-limiting circuit have the characteristic of negative temperature coefficient.
Under different power circuit output end VCC voltage, the cut-off current of test current-limiting circuit, the result is as follows:
| Sequence number | Supply voltage V | Cut-off current mA |
| 1 | 6 | 61 |
| 2 | 7 | 86 |
| 3 | 8 | 103 |
| 4 | 9 | 112 |
| 5 | 10 | 115 |
| 6 | 11 | 118 |
| 7 | 12 | 120 |
| 8 | 13 | 121 |
| 9 | 14 | 122 |
| 10 | 15 | 123 |
| 11 | 16 | 124 |
| 12 | 17 | 125 |
| 13 | 18 | 125 |
| 14 | 19 | 125 |
| 15 | 20 | 125 |
| 16 | 22 | 125 |
| 17 | 24 | 125 |
| 18 | 26 | 125 |
| 19 | 28 | 125 |
| 20 | 30 | 125 |
When power circuit output end VCC voltage be set to+during 12V, current limliting triode Q7 when different temperatures, the cut-off current of test current-limiting circuit, the result is as follows:
| Sequence number | Triode temperature ℃ | Cut-off current mA |
| 1 | 20 | 123 |
| 2 | 30 | 120 |
| 3 | 40 | 116 |
| 4 | 50 | 112 |
| 5 | 60 | 108 |
| 6 | 70 | 104 |
| 7 | 80 | 101 |
| 8 | 90 | 97 |
| 9 | 100 | 93 |
| 10 | 110 | 90 |
| 11 | 120 | 86 |
| 12 | 130 | 82 |
| 13 | 140 | 78 |
| 14 | 150 | 75 |
Claims (4)
1. current-limiting circuit, it is characterized in that, comprise two current sampling resistors (R38, R39) in parallel, the filter capacitor (C26) that links to each other with output terminal, current limliting triode (Q7), control triode (Q8), gauge tap triode (Q9), filter capacitor (C26) ground connection; The base stage of current limliting triode (Q7) is connected with the collector of control triode (Q8); The collector of current limliting triode (Q7) is connected with output terminal; The emitter of current limliting triode (Q7) is connected with power circuit output end (VCC); The base stage of control triode (Q8) links to each other with power circuit output end (VCC); The emitter of control triode (Q8) is connected with+12V power supply; Two current sampling resistors (R38, R39) in parallel be connected to power circuit output end (VCC) and+the 12V power supply between; The grounded emitter of gauge tap triode (Q9); The base stage of gauge tap triode (Q9) is connected with the enable signal end, is connected with current-limiting resistance (R42) therebetween; The collector of gauge tap triode (Q9) links to each other with the base stage of current limliting triode (Q7), is in series with divider resistance (R40) therebetween; The collector of control triode (Q8) is connected with+12V power supply, is connected with divider resistance (R41) therebetween.
2. current-limiting circuit according to claim 1 is characterized in that, current limliting triode (Q7) and control triode (Q8) are the positive-negative-positive triode, and gauge tap triode (Q9) is NPN type triode.
3. current-limiting circuit according to claim 1 and 2 is characterized in that, base stage and the power circuit output end (VCC) of control triode (Q8) also are connected with divider resistance (R37) therebetween.
4. current-limiting circuit according to claim 1 and 2 is characterized in that, is connected with buffer resistance (R36) between power circuit output end (VCC) and the output terminal.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201210584586.1A CN103049029B (en) | 2012-12-30 | 2012-12-30 | Current-limiting circuit |
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| CN201210584586.1A CN103049029B (en) | 2012-12-30 | 2012-12-30 | Current-limiting circuit |
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| CN103049029B CN103049029B (en) | 2015-03-18 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103729006A (en) * | 2013-11-21 | 2014-04-16 | 成都市宏山科技有限公司 | Camera protection circuit |
| CN105140997A (en) * | 2015-09-09 | 2015-12-09 | 成都川睿科技有限公司 | Intelligent lamp charger of intelligent traffic system |
| CN107888063A (en) * | 2018-02-11 | 2018-04-06 | 漳州科华技术有限责任公司 | A kind of output current peak factor method and device for improving inverter |
| CN112267549A (en) * | 2020-10-10 | 2021-01-26 | 浙江飞创环境科技有限公司 | Integrated pump station |
| 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 |
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| CN101505055A (en) * | 2008-12-30 | 2009-08-12 | 上海英联电子系统有限公司 | Active surge current control circuit |
| CN101771272A (en) * | 2010-03-02 | 2010-07-07 | 南京亚派科技实业有限公司 | Over current protection circuit |
| US20100214702A1 (en) * | 2009-02-24 | 2010-08-26 | Zhongshan Broad-Ocean Motor Co., Ltd. | Over-current protection circuit and motor controller comprising the same |
| CN102082430A (en) * | 2011-01-27 | 2011-06-01 | 广州金升阳科技有限公司 | Surge suppression circuit |
| CN203102060U (en) * | 2012-12-30 | 2013-07-31 | 青岛东软载波科技股份有限公司 | Current-limiting circuit |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101505055A (en) * | 2008-12-30 | 2009-08-12 | 上海英联电子系统有限公司 | Active surge current control circuit |
| US20100214702A1 (en) * | 2009-02-24 | 2010-08-26 | Zhongshan Broad-Ocean Motor Co., Ltd. | Over-current protection circuit and motor controller comprising the same |
| CN101771272A (en) * | 2010-03-02 | 2010-07-07 | 南京亚派科技实业有限公司 | Over current protection circuit |
| CN102082430A (en) * | 2011-01-27 | 2011-06-01 | 广州金升阳科技有限公司 | Surge suppression circuit |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103729006A (en) * | 2013-11-21 | 2014-04-16 | 成都市宏山科技有限公司 | Camera protection circuit |
| CN105140997A (en) * | 2015-09-09 | 2015-12-09 | 成都川睿科技有限公司 | Intelligent lamp charger of intelligent traffic system |
| CN107888063A (en) * | 2018-02-11 | 2018-04-06 | 漳州科华技术有限责任公司 | A kind of output current peak factor method and device for improving inverter |
| CN107888063B (en) * | 2018-02-11 | 2019-10-01 | 漳州科华技术有限责任公司 | A kind of output current peak coefficient method and device improving inverter |
| CN112267549A (en) * | 2020-10-10 | 2021-01-26 | 浙江飞创环境科技有限公司 | Integrated pump station |
| 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 |
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| CN103049029B (en) | 2015-03-18 |
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