CN203708097U - Novel switch power supply short circuit protection circuit - Google Patents
Novel switch power supply short circuit protection circuit Download PDFInfo
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- CN203708097U CN203708097U CN201420052927.5U CN201420052927U CN203708097U CN 203708097 U CN203708097 U CN 203708097U CN 201420052927 U CN201420052927 U CN 201420052927U CN 203708097 U CN203708097 U CN 203708097U
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- 239000003990 capacitor Substances 0.000 claims abstract description 27
- 238000005070 sampling Methods 0.000 claims abstract description 23
- 230000008878 coupling Effects 0.000 claims description 22
- 238000010168 coupling process Methods 0.000 claims description 22
- 238000005859 coupling reaction Methods 0.000 claims description 22
- 230000001939 inductive effect Effects 0.000 abstract 1
- 230000001681 protective effect Effects 0.000 description 14
- 230000000694 effects Effects 0.000 description 8
- 238000001914 filtration Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 4
- 230000006378 damage Effects 0.000 description 3
- 230000001186 cumulative effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- 230000010349 pulsation Effects 0.000 description 2
- GOLXNESZZPUPJE-UHFFFAOYSA-N spiromesifen Chemical compound CC1=CC(C)=CC(C)=C1C(C(O1)=O)=C(OC(=O)CC(C)(C)C)C11CCCC1 GOLXNESZZPUPJE-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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Abstract
The utility model relates to a novel switch power supply short circuit protection circuit. The protection circuit comprises an input sampling circuit, a comparison circuit and a switch circuit which are connected in order. The input end of the input sampling circuit is coupled with a primary leading wire of a switch power supply input transformer through an inductive element, and the output end of the input sampling circuit is connected with the input end of the comparison circuit. The output end of the comparison circuit is connected with the input end of the switch circuit. The output end of the switch circuit is connected with the control end of the switch power supply. Through mutual cooperation of a resistor, a capacitor, a diode and a triode transistor in the comparison circuit, reference voltage adjustment of a comparator is achieved. The protection circuit is simple in structure, is easy to debug, and has high temperature stability, and short circuit power consumption is less affected by parameter drifting.
Description
Technical field
The utility model relates to switch power technology field, is specifically related to a kind of short circuit protecting circuit for switch power of novelty.
Background technology
Switching Power Supply is widely used in industry and national defence field, in the military-civil electronic systems such as space flight, aviation, boats and ships, weapons, railway, communication, medical electronics, industrial automation equipment, is used widely.When Switching Power Supply using or debug process in there is overload or when short circuit, the protective circuit guarantee that is absolutely necessary.Protective circuit can greatly reduce the damage to Switching Power Supply, guarantees that machinery equipment runs well and personal safety.
At present extensively adopt and subtract flow pattern protective circuit, when subtracting flow pattern protective circuit and protecting, input current reduces, and overload is while cancelling, and circuit can recover normally to work.The existing deficiency that subtracts flow pattern protective circuit and mainly contain following four aspects: the one, existing protective circuit is slightly aobvious complicated, and components and parts are many, debug difficulties; The 2nd, the electric capacity for output with several thousand microfarads, short-circuit protection circuit is easy to enter guard mode.The 3rd, power consumption when protection is bigger than normal; The 4th, circuit, to ambient temperature sensitivity, makes Switching Power Supply short-circuit dissipation difference under high low temperature large, even can cause, after high low temperature short trouble is eliminated, can not automatically recovering normal operating conditions.
Utility model content
The purpose of this utility model is to provide a kind of short circuit protecting circuit for switch power of novelty, this protective circuit not only simple in structure, be easy to debugging, also there is lower protection power consumption and higher temperature stability, and short-circuit dissipation affected by parameter drift little.
For achieving the above object, the utility model has adopted following technical scheme: a kind of short circuit protecting circuit for switch power of novelty, comprises connected successively input sampling circuit, comparison circuit and switching circuit; The input of described input sampling circuit is by the elementary lead-in wire coupling of perceptual device and Switching Power Supply input transformer, output is connected with the input of comparison circuit, the output of described comparison circuit is connected with the input of switching circuit, and the output of described switching circuit is connected with the control end of Switching Power Supply.
The effect of input sampling circuit is to gather the elementary current signal of switching mode power supply transformer, and opens or close protective circuit according to the size of current signal.Described input sampling circuit comprises coupling inductance L1, resistance R 6, resistance R 7, resistance R 8, diode D1, diode D3 and capacitor C 2; Described coupling inductance L1 is connected in parallel on resistance R 6 two ends, the elementary lead-in wire coupling of described coupling inductance and Switching Power Supply input transformer; Described resistance R 6 one end ground connection, the other end is connected with diode D1 anode; Diode D1 negative electrode is connected with diode D3 anode, and diode D3 negative electrode is connected with the input of comparison circuit; Diode D1 negative electrode is through resistance R 8 ground connection; Diode D3 negative electrode is through resistance R 7 ground connection, and capacitor C 2 is connected in parallel on resistance R 7 two ends.The output of described input sampling circuit is the negative electrode of diode D3.Become the voltage signal of pulsation by the pulsating current of coupling inductance L1 coupling transformer T1 primary coil, then become direct voltage by diode D1 and D3, resistance R 7, R8 and capacitor C 2 rectifying and wave-filterings.
The effect of comparison circuit is that the reference voltage of collection signal voltage and comparator N1 negative input end is compared, and opens or closing switch circuit according to comparative result.Described comparison circuit comprises comparator N1, capacitor C 1, triode V3, resistance R 2, resistance R 3, resistance R 4 and resistance R 5; The power input of described comparator N1 connects power supply VCC, earth terminal ground connection, the output of positive input terminal and input sampling circuit is connected, and negative input end is connected with resistance R 4 with diode D2 negative electrode respectively, and output is connected with resistance R 2 with the input of switching circuit respectively; The anode of described diode D2 is connected with power supply VCC through resistance R 3; Described capacitor C 1 is connected in parallel on resistance R 3 two ends; The other end that described resistance R 4 is connected with comparator N1 negative input end is through resistance R 5 ground connection; The other end that described resistance R 2 is connected with comparator N1 output is connected with the base stage of triode V3; Triode V3 collector electrode is connected with one end that resistance R 5 is connected with resistance R 4, grounded emitter.The input of described comparison circuit is the positive input terminal of comparator N1, and the output of comparison circuit is the output of comparator N1.Described diode D2 and D3 are the components and parts of same temperature coefficient, and diode D2 can eliminate the temperature impact of diode D3, reduce the difference of Switching Power Supply short-circuit dissipation under high low temperature, improve temperature stability.
Control end to Switching Power Supply when the effect of switching circuit is short-circuit protection is controlled, and then controls pulse width modulator, allows Switching Power Supply in guard mode.Described control end comprises soft start end, forbids the shutdown side of end, accessory power supply etc.Described switching circuit comprises triode V2 and resistance R 1; The base stage of described triode V2 is connected with the output of comparison circuit through resistance R 1, and the control end of collector electrode and Switching Power Supply is connected, grounded emitter.
Operation principle of the present utility model:
First, input sampling circuit is by the elementary lead-in wire of coupling inductance L1 and the Switching Power Supply input transformer T1 elementary current signal of Gather and input transformer T1 that is coupled; Again input signal is carried out being transferred to after rectifying and wave-filtering the positive input terminal of comparison circuit comparator N1.Gathering current signal by coupled modes can't harm relatively; Control the current signal amplitude size collecting by diode D1, resistance R 6 and resistance R 8; By diode D3, resistance R 7 and capacitor C 2, AC signal rectifying and wave-filtering is become to direct current signal.The elementary lead-in wire of coupling inductance L1 and Switching Power Supply input transformer T1 is coupled by magnet ring or instrument transformer.
Secondly, the effect of comparison circuit is that the reference voltage of collection signal voltage and comparator N1 negative input end is compared, and opens or closing switch circuit according to comparative result.If collection signal voltage is greater than reference voltage, comparator N1 output output HIGH voltage, makes the triode V2 conducting in switching circuit, enters guard mode.The size of reference voltage value is determining whether to enter the size of short-circuit protection state and protection power consumption.Reference voltage value is lower, more easily enters protection, and protection power consumption is lower.Existing protective circuit of switch power source, in the time that Switching Power Supply is opened moment or the external large bulk capacitance of output and caused instantaneous large-current, very easily enters guard mode, and the normal work of short-circuit protection circuit is impacted.In the present invention, the reference voltage value of comparator N1 negative input end is by diode D2, resistance R 3, R4, R5 and the common decision of capacitor C 1.Open moment in Switching Power Supply, capacitor C 1 in comparison circuit is charged, by resistance R 3 short circuits, the reference voltage value of comparator N1 negative input end is close to VCC supply voltage, be not less than collection signal magnitude of voltage, so can make Switching Power Supply enter stably operating state, offset by capacitor C 1 impact that booting moment input current causes more greatly.After capacitor C 1 has been charged, the existence of capacitor C 1 no longer affects the reference voltage value of comparator N1 negative input end.In the time that collection signal magnitude of voltage is greater than the reference voltage value of comparator N1 negative input end, comparator N1 output output HIGH voltage signal, triode V2 and triode V3 conducting simultaneously.
Again, because the soft start end of the collector electrode of triode V2 and Switching Power Supply or forbid that the control end such as shutdown side of end or accessory power supply is connected, so after triode V2 conducting, the voltage of fault control end, makes Switching Power Supply in guard mode.After triode V3 conducting, resistance R 5 short circuits, thus make reference voltage value only relevant with the resistance size of resistance R 4 and R3.Due to the time-delay characteristics of transistor cut-off, during guard mode, R5 is short circuit always.By the resistance of adjusting resistance R4 and R3, make the reference voltage value under guard mode very little, thereby protective current is reduced, greatly reduce protection power consumption.Whether output is fully loaded with to enter to protect and is determined by resistance R 5; R5 is larger; reference voltage value is larger; allow carrying of band just larger; and in the time of short-circuit protection state, resistance R 5 is short-circuit condition always, the size of output loading can not affect protection power consumption; short-circuit protection circuit of the present invention is easy to debugging, short-circuit dissipation is low, and long-term short-circuit protection can be provided.After short trouble is eliminated, utilize the time-delay characteristics of transistor turns, reference voltage value is cumulative, and the output voltage of comparator N1 reduces gradually, and triode V3 becomes cut-off by conducting, and Switching Power Supply is recovered normal operating conditions.
From above technical scheme, the utility model cooperatively interacts by the resistance in comparison circuit, electric capacity, diode and transistor, has realized the adjusting of comparator reference voltage.By adjusting the size of comparator reference voltage, the reference voltage while making normally to work is high, can guarantee fully loaded and open moment and normally work; Reference voltage while making short-circuit protection declines, and can reduce short-circuit protection power consumption.In the time that short-circuit protection is cancelled, high voltage when reference voltage goes back up to initial guard mode again gradually, switching power circuit recovers normal work.The utility model short circuit protecting circuit for switch power not only simple in structure, be easy to debugging, also there is higher temperature stability, it is little that short-circuit dissipation is affected by parameter drift.
Accompanying drawing explanation
Fig. 1 is circuit theory diagrams of the present utility model;
The oscillogram of comparator N1 output when Fig. 2 is guard mode.
Wherein:
1, input sampling circuit, 2, comparison circuit, 3, switching circuit.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described further:
The short circuit protecting circuit for switch power of a kind of novelty as shown in Figure 1, comprises connected successively input sampling circuit, comparison circuit and switching circuit; The input of described input sampling circuit is by the elementary lead-in wire coupling of perceptual device and Switching Power Supply input transformer, output is connected with the input of comparison circuit, the output of described comparison circuit is connected with the input of switching circuit, and the output of described switching circuit is connected with the control end of Switching Power Supply.
The effect of input sampling circuit is to gather the elementary current signal of switching mode power supply transformer, and opens or close protective circuit according to the size of current signal.Described input sampling circuit comprises coupling inductance L1, resistance R 6, resistance R 7, resistance R 8, diode D1, diode D3 and capacitor C 2; Described coupling inductance L1 is connected in parallel on resistance R 6 two ends, the elementary lead-in wire coupling of described coupling inductance and Switching Power Supply input transformer; Described resistance R 6 one end ground connection, the other end is connected with diode D1 anode; Diode D1 negative electrode is connected with diode D3 anode, and diode D3 negative electrode is connected with the input of comparison circuit; Diode D1 negative electrode is through resistance R 8 ground connection; Diode D3 negative electrode is through resistance R 7 ground connection, and capacitor C 2 is connected in parallel on resistance R 7 two ends.The output of described input sampling circuit is the negative electrode of diode D3.Become the voltage signal of pulsation by the pulsating current of coupling inductance L1 coupling transformer T1 primary coil, then become direct voltage by diode D1 and D3, resistance R 7, R8 and capacitor C 2 rectifying and wave-filterings.
The effect of comparison circuit is that the reference voltage of collection signal voltage and comparator N1 negative input end is compared, and opens or closing switch circuit according to comparative result.Described comparison circuit comprises comparator N1, capacitor C 1, triode V3, resistance R 2, resistance R 3, resistance R 4 and resistance R 5; The power input of described comparator N1 connects power supply VCC, earth terminal ground connection, the output of positive input terminal and input sampling circuit is connected, and negative input end is connected with resistance R 4 with diode D2 negative electrode respectively, and output is connected with resistance R 2 with the input of switching circuit respectively; The anode of described diode D2 is connected with power supply VCC through resistance R 3; Described capacitor C 1 is connected in parallel on resistance R 3 two ends; The other end that described resistance R 4 is connected with comparator N1 negative input end is through resistance R 5 ground connection; The other end that described resistance R 2 is connected with comparator N1 output is connected with the base stage of triode V3; Triode V3 collector electrode is connected with one end that resistance R 5 is connected with resistance R 4, grounded emitter.The input of described comparison circuit is the positive input terminal of comparator N1, and the output of comparison circuit is the output of comparator N1.Described diode D2 and D3 are the components and parts of same temperature coefficient, and diode D2 can eliminate the temperature impact of diode D3, reduce the difference of Switching Power Supply short-circuit dissipation under high low temperature, improve temperature stability.
Control end to Switching Power Supply when the effect of switching circuit is short-circuit protection is controlled, and then controls pulse width modulator, allows Switching Power Supply in guard mode.Described control end comprises soft start end, forbids the shutdown side of end, accessory power supply etc.Described switching circuit comprises triode V2 and resistance R 1; The base stage of described triode V2 is connected with the output of comparison circuit through resistance R 1, and the control end of collector electrode and Switching Power Supply is connected, grounded emitter.
Workflow of the present utility model is:
First, input sampling circuit is by the elementary lead-in wire of coupling inductance L1 and the Switching Power Supply input transformer T1 elementary current signal of Gather and input transformer T1 that is coupled; Again input signal is carried out being transferred to after rectifying and wave-filtering the positive input terminal of comparison circuit comparator N1.Gathering current signal by coupled modes can't harm relatively; Control the current signal amplitude size collecting by diode D1, resistance R 6 and resistance R 8; By diode D3, resistance R 7 and capacitor C 2, AC signal rectifying and wave-filtering is become to direct current signal.
Secondly, the effect of comparison circuit is that the reference voltage of collection signal voltage and comparator N1 negative input end is compared, and opens or closing switch circuit according to comparative result.If collection signal magnitude of voltage is greater than reference voltage value, comparator N1 output output HIGH voltage, makes the triode V2 conducting in switching circuit, enters guard mode.The size of reference voltage value is determining whether to enter the size of short-circuit protection state and protection power consumption.Reference voltage value is lower, more easily enters protection, and protection power consumption is lower.Existing protective circuit of switch power source, in the time that Switching Power Supply is opened moment or the external large bulk capacitance of output and caused instantaneous large-current, very easily enters guard mode, and the normal work of short-circuit protection circuit is impacted.In the present invention, the reference voltage value of comparator N1 negative input end is by diode D2, resistance R 3, R4, R5 and the common decision of capacitor C 1.Open moment in Switching Power Supply, capacitor C 1 in comparison circuit is charged, by resistance R 3 short circuits, the reference voltage value of comparator N1 negative input end is close to VCC supply voltage, be not less than collection signal magnitude of voltage, so can make Switching Power Supply enter stably operating state, offset by capacitor C 1 impact that booting moment input current causes more greatly.After capacitor C 1 has been charged, the existence of capacitor C 1 no longer affects the reference voltage value of comparator N1 negative input end.In the time that collection signal magnitude of voltage is greater than the reference voltage value of comparator N1 negative input end, comparator N1 output output HIGH voltage signal, triode V2 and triode V3 conducting simultaneously.
Again, because the soft start end of the collector electrode of triode V2 and Switching Power Supply or forbid that the control end such as shutdown side of end or accessory power supply is connected, so after triode V2 conducting, the voltage of fault control end, makes Switching Power Supply in guard mode.After triode V3 conducting, resistance R 5 short circuits, thus make reference voltage value only relevant with the resistance size of resistance R 4 and R3.Due to the time-delay characteristics of transistor cut-off, during guard mode, R5 is short circuit always.By the resistance of adjusting resistance R4 and R3, make the reference voltage value under guard mode very little, thereby protective current is reduced, greatly reduce protection power consumption.The output voltage pulse duration of comparator is relevant with the reference voltage of comparator, and reference voltage is lower, and pulse duration is wider, and protection power consumption is lower.As shown in Figure 2, comparator N1 output end voltage is pulse condition, but compares with existing protective circuit of switch power source, and it is large that pulse duration becomes, so the protection power consumption of known the utility model short-circuit protection circuit greatly reduces.Whether output is fully loaded with to enter to protect and is determined by resistance R 5; R5 is larger; reference voltage value is larger; allow carrying of band just larger; and in the time of short-circuit protection state, resistance R 5 is short-circuit condition always, the size of output loading can not affect protection power consumption; short-circuit protection circuit of the present invention is easy to debugging, short-circuit dissipation is low, and long-term short-circuit protection can be provided.After short trouble is eliminated, utilize the time-delay characteristics of transistor turns, reference voltage value is cumulative, and the output voltage of comparator N1 reduces gradually, and triode V3 becomes cut-off by conducting, and Switching Power Supply is recovered normal operating conditions.
Above-described embodiment is described preferred implementation of the present utility model; not scope of the present utility model is limited; do not departing under the prerequisite of the utility model design spirit; various distortion and improvement that those of ordinary skills make the technical solution of the utility model, all should fall in the definite protection range of the utility model claims.
Claims (6)
1. a novel short circuit protecting circuit for switch power, is characterized in that: comprise connected successively input sampling circuit, comparison circuit and switching circuit; The input of described input sampling circuit is by the elementary lead-in wire coupling of perceptual device and Switching Power Supply input transformer, output is connected with the input of comparison circuit, the output of described comparison circuit is connected with the input of switching circuit, and the output of described switching circuit is connected with the control end of Switching Power Supply.
2. the short circuit protecting circuit for switch power of a kind of novelty according to claim 1, is characterized in that: described input sampling circuit comprises coupling inductance L1, resistance R 6, resistance R 7, resistance R 8, diode D1, diode D3 and capacitor C 2; Described coupling inductance L1 is connected in parallel on resistance R 6 two ends, the elementary lead-in wire coupling of described coupling inductance and Switching Power Supply input transformer; Described resistance R 6 one end ground connection, the other end is connected with diode D1 anode; Diode D1 negative electrode is connected with diode D3 anode, and diode D3 negative electrode is connected with the input of comparison circuit; Diode D1 negative electrode is through resistance R 8 ground connection; Diode D3 negative electrode is through resistance R 7 ground connection, and capacitor C 2 is connected in parallel on resistance R 7 two ends.
3. the short circuit protecting circuit for switch power of a kind of novelty according to claim 1, is characterized in that: described comparison circuit comprises comparator N1, capacitor C 1, triode V3, resistance R 2, resistance R 3, resistance R 4 and resistance R 5; The power input of described comparator N1 connects power supply VCC, earth terminal ground connection, the output of positive input terminal and input sampling circuit is connected, and negative input end is connected with resistance R 4 with diode D2 negative electrode respectively, and output is connected with resistance R 2 with the input of switching circuit respectively; The anode of described diode D2 is connected with power supply VCC through resistance R 3; Described capacitor C 1 is connected in parallel on resistance R 3 two ends; The other end that described resistance R 4 is connected with comparator N1 negative input end is through resistance R 5 ground connection; The other end that described resistance R 2 is connected with comparator N1 output is connected with the base stage of triode V3; Triode V3 collector electrode is connected with one end that resistance R 5 is connected with resistance R 4, grounded emitter.
4. the short circuit protecting circuit for switch power of a kind of novelty according to claim 1, is characterized in that: described switching circuit comprises triode V2 and resistance R 1; The base stage of described triode V2 is connected with the output of comparison circuit through resistance R 1, and the control end of collector electrode and Switching Power Supply is connected, grounded emitter.
5. according to the short circuit protecting circuit for switch power of a kind of novelty described in claim 2 or 3, it is characterized in that: the output of described input sampling circuit is the negative electrode of diode D3.
6. according to the short circuit protecting circuit for switch power of a kind of novelty described in claim 3 or 4, it is characterized in that: the input of described comparison circuit is the positive input terminal of comparator N1, the output of comparison circuit is the output of comparator N1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420052927.5U CN203708097U (en) | 2014-01-27 | 2014-01-27 | Novel switch power supply short circuit protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420052927.5U CN203708097U (en) | 2014-01-27 | 2014-01-27 | Novel switch power supply short circuit protection circuit |
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| Publication Number | Publication Date |
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| CN203708097U true CN203708097U (en) | 2014-07-09 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201420052927.5U Expired - Fee Related CN203708097U (en) | 2014-01-27 | 2014-01-27 | Novel switch power supply short circuit protection circuit |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105514932A (en) * | 2015-12-08 | 2016-04-20 | 深圳天珑无线科技有限公司 | Short circuit protection circuit of power supply |
| CN107786073A (en) * | 2017-12-09 | 2018-03-09 | 中国电子科技集团公司第四十三研究所 | A kind of Switching Power Supply standard cell circuit and device |
| CN110021916A (en) * | 2019-05-09 | 2019-07-16 | 中国电子科技集团公司第四十三研究所 | A kind of short circuit protecting circuit for switch power and its guard method |
-
2014
- 2014-01-27 CN CN201420052927.5U patent/CN203708097U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105514932A (en) * | 2015-12-08 | 2016-04-20 | 深圳天珑无线科技有限公司 | Short circuit protection circuit of power supply |
| CN107786073A (en) * | 2017-12-09 | 2018-03-09 | 中国电子科技集团公司第四十三研究所 | A kind of Switching Power Supply standard cell circuit and device |
| CN107786073B (en) * | 2017-12-09 | 2023-11-07 | 中国电子科技集团公司第四十三研究所 | Standard unit circuit and device of switching power supply |
| CN110021916A (en) * | 2019-05-09 | 2019-07-16 | 中国电子科技集团公司第四十三研究所 | A kind of short circuit protecting circuit for switch power and its guard method |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20140709 |
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| CF01 | Termination of patent right due to non-payment of annual fee |