CN204258271U - A kind of under-voltage protective switch of the short circuit supply unit - Google Patents
A kind of under-voltage protective switch of the short circuit supply unit Download PDFInfo
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- CN204258271U CN204258271U CN201420747192.8U CN201420747192U CN204258271U CN 204258271 U CN204258271 U CN 204258271U CN 201420747192 U CN201420747192 U CN 201420747192U CN 204258271 U CN204258271 U CN 204258271U
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Abstract
The utility model discloses a kind of under-voltage protective switch of the short circuit supply unit, comprise pwm control circuit, output rectifier and filter, the first optocoupler, the second optocoupler, under-voltage short-circuit protection circuit, overvoltage crowbar; Overvoltage crowbar connects under-voltage short-circuit protection circuit, the second optocoupler and output rectifier and filter, and the second optocoupler connects pwm control circuit, and under-voltage short-circuit protection circuit connects output rectifier and filter; Under-voltage or the short circuit being detected output voltage by under-voltage short-circuit protection circuit is abnormal; when there is under-voltage or short circuit, triggered voltage protection circuit, under-voltage short-circuit protection circuit and overvoltage crowbar form loop; the second optocoupler conducting is made to produce low level to close pwm control circuit; thus under-voltage or short circuit is abnormal time stop the output of output voltage; thus under-voltage or short circuit are protected extremely fast; ensure that the reliability of the under-voltage of high-peak power switch power supply system or short-circuit protection; improve product quality, reduce cost.
Description
Technical field
The utility model relates to switch power technology field, particularly the under-voltage protective switch of the short circuit supply unit of one.
Background technology
Existing power protection system does not all relate to quick under-voltage protection; Part is had to relate to short-circuit protection, but circuit structure more complicated, cost is higher.In user's use procedure if there is under-voltage or short circuit is abnormal time, can assemble very large energy instantaneously, the energy stored in the energy storage device (as electric capacity, inductance) of Systematical control can not get releasing in time, even if there is short-circuit protection can not solve under-voltage problem.Especially occur the power power-supply that peak power is very large, under-voltage or short-circuit reaction overlong time easily causes source element to damage.
Thus prior art need to improve.
Utility model content
In view of above-mentioned the deficiencies in the prior art part, the purpose of this utility model is to provide a kind of under-voltage protective switch of the short circuit supply unit, to solve the problem that existing switching power unit does not have under-voltage protection.
In order to achieve the above object, the utility model takes following technical scheme:
A kind of under-voltage protective switch of the short circuit supply unit; comprise AC voltage input circuit, EMI circuit, input rectifying filter circuit, power switch circuit, pwm control circuit, output rectifier and filter, feedback control circuit, high-frequency isolation transformer, the first optocoupler, the second optocoupler; it is characterized in that, also comprise:
The under-voltage short-circuit protection circuit of triggered voltage protection circuit during for detecting output voltage under-voltage or short circuit;
During for being triggered and under-voltage short-circuit protection circuit form loop, make the second optocoupler conducting produce low level to close pwm control circuit, to stop the overvoltage crowbar of output of output voltage;
Described AC voltage input circuit, EMI circuit, input rectifying filter circuit connects successively, described input rectifying filter circuit connects power switch circuit, pwm control circuit and high-frequency isolation transformer, described power switch circuit connects pwm control circuit and high-frequency isolation transformer, described pwm control circuit connects high-frequency isolation transformer, first optocoupler U1 and the second optocoupler U2, described first optocoupler connects feedback control circuit, second optocoupler connects overvoltage crowbar, output rectifier and filter connects high-frequency isolation transformer, interface, feedback control circuit, overvoltage crowbar and under-voltage short-circuit protection circuit, described overvoltage crowbar connects under-voltage short-circuit protection circuit.
In described under-voltage protective switch of the short circuit supply unit, described under-voltage short-circuit protection circuit comprises the first diode, the second diode, the 3rd diode and the first electric capacity; The positive pole of described first diode connects the output of output rectifier and filter and the negative pole of the second diode; the negative pole of described first diode connects the negative pole of the 3rd diode; the positive pole of the 3rd diode connects overvoltage crowbar, also by the first capacity earth, the positive pole of described second diode connects overvoltage crowbar.
In described under-voltage protective switch of the short circuit supply unit, described overvoltage crowbar comprises: the first triode, the second triode, the first resistance, the second resistance, the 3rd resistance, the 4th resistance and the 4th diode, the emitter of described first triode connects the positive pole of the 3rd diode and one end of the first resistance, the base stage of the first triode connects the other end of the first resistance R1 and one end of the second resistance, the other end of described second resistance connects the positive pole of the second diode and the collector electrode of the second triode, the collector electrode of the first triode connects the positive pole of the diode of the second optocoupler by the 3rd resistance, the minus earth of the diode of the second optocoupler, the base stage of the second triode connects the positive pole of the 4th diode, also by the 4th grounding through resistance, the negative pole of the 4th diode connects the output of output rectifier and filter, the grounded emitter of the second triode.
In described under-voltage protective switch of the short circuit supply unit; described overvoltage crowbar also comprises the second electric capacity and the 5th resistance; one end of described second electric capacity connects the base stage of the first triode; the other end ground connection of the second electric capacity; one end of 5th resistance is connected the positive pole of the diode of the second optocoupler, is also connected the collector electrode of the first triode by the 3rd resistance, the other end ground connection of the 5th resistance.
In described under-voltage protective switch of the short circuit supply unit, described overvoltage crowbar also comprises the 4th electric capacity, described 4th electric capacity and the first resistor coupled in parallel.
In described under-voltage protective switch of the short circuit supply unit; described overvoltage crowbar also comprises the 6th resistance and the 5th electric capacity; one end of described 6th resistance connects the positive pole of the 4th diode; the other end of the 6th resistance connect the second triode base stage, also by the 4th grounding through resistance; one end of described 5th electric capacity connects the base stage of the second triode, the other end ground connection of the 5th electric capacity.
In described under-voltage protective switch of the short circuit supply unit, described 3rd diode employing model is 1N4148, pressure drop is the voltage stabilizing didoe of 0.7V.
In described under-voltage protective switch of the short circuit supply unit, described 4th diode is voltage stabilizing didoe, and described first triode is PNP triode, and the second triode is NPN triode.
Compared to prior art, the under-voltage protective switch of the short circuit supply unit that the utility model provides, under-voltage or the short circuit being detected output voltage by under-voltage short-circuit protection circuit is abnormal, the triggered voltage protection circuit when there is under-voltage or short circuit, under-voltage short-circuit protection circuit and overvoltage crowbar form loop, the second optocoupler conducting is made to produce low level to close pwm control circuit, thus under-voltage or short circuit is abnormal time stop the output of output voltage, thus under-voltage or short circuit are protected extremely fast, ensure that the reliability of the under-voltage of high-peak power switch power supply system or short-circuit protection, improve product quality, reduce cost.
Accompanying drawing explanation
The structured flowchart of the Application Example of the under-voltage protective switch of the short circuit supply unit that Fig. 1 provides for the utility model.
The circuit diagram of overvoltage crowbar and under-voltage short-circuit protection circuit in the under-voltage protective switch of the short circuit supply unit that Fig. 2 provides for the utility model embodiment.
Embodiment
The utility model provides a kind of under-voltage protective switch of the short circuit supply unit, for making the purpose of this utility model, technical scheme and effect clearly, clearly, further describes the utility model referring to the accompanying drawing embodiment that develops simultaneously.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.
Refer to Fig. 1, existing switching power unit is made up of AC voltage input circuit 10, EMI circuit 20, input rectifying filter circuit 30, power switch circuit 40, pwm control circuit 50, output rectifier and filter 60, feedback control circuit 70, overvoltage crowbar 80, high-frequency isolation transformer T1, the first optocoupler U1, the second optocoupler U2 usually.The present embodiment is by increasing under-voltage short-circuit protection circuit 90; and improve the 26S Proteasome Structure and Function of overvoltage crowbar 80, extremely can protect fast under-voltage or short circuit, ensure that the reliability of the under-voltage of high-peak power switch power supply system or short-circuit protection; improve product quality, reduce cost.
In this enforcement, AC voltage input circuit 10, EMI circuit 20, input rectifying filter circuit 30 connect successively.Described input rectifying filter circuit 30 connects power switch circuit 40, pwm control circuit 50 and high-frequency isolation transformer T1, described power switch circuit 40 connects pwm control circuit 50 and high-frequency isolation transformer T1, described pwm control circuit 50 connects high-frequency isolation transformer T1, the collector electrode of the first optocoupler U1 and the collector electrode of the second optocoupler U2, the positive pole of described first optocoupler U1 is connected feedback control circuit with negative pole, the grounded emitter of the first optocoupler U1, the positive pole of the second optocoupler U2 connects overvoltage crowbar 80, the emitter of the second optocoupler U2 and minus earth, output rectifier and filter 60 connects high-frequency isolation transformer T1, interface J1, feedback control circuit 70, overvoltage crowbar 80 and under-voltage short-circuit protection circuit 90, described overvoltage crowbar 80 connects under-voltage short-circuit protection circuit 90.
Civil power inputs from AC voltage input circuit 10, after EMI circuit 20 filtering electromagnetic interference, rectifying and wave-filtering is carried out again through input rectifying filter circuit 30, convert required voltage to by high-frequency isolation transformer T1, obtain output voltage after eventually passing output rectifier and filter 60 rectifying and wave-filtering and export from interface J1.Feedback control circuit 70, overvoltage crowbar 80 and under-voltage short-circuit protection circuit 90 Real-Time Monitoring output voltage.Feedback control circuit 70 controls the conducting state of the first optocoupler U1 according to the magnitude of voltage of output voltage, thus the operating state controlling pwm control circuit 50 adjusts the voltage transitions of high-frequency isolation transformer T1, make output voltage increase or decline to reach default output pressure value.When described under-voltage short-circuit protection circuit 90 detects output voltage under-voltage or short circuit, triggered voltage protection circuit 80 forms loop, makes the second optocoupler conducting produce low level to close pwm control circuit, thus stops the output of output voltage.
Described under-voltage short-circuit protection circuit 90 comprises the first diode D1, the second diode D2, the 3rd diode D3 and the first electric capacity C1; The positive pole of described first diode D1 connects the output OUT(of output rectifier and filter 60 for detecting output voltage) and the negative pole of the second diode D2; the negative pole of described first diode D1 connects the negative pole of the 3rd diode D3; the positive pole of the 3rd diode D3 connects overvoltage crowbar 80, also by the first electric capacity C1 ground connection, the positive pole of described second diode D2 connects overvoltage crowbar 80.
Described overvoltage crowbar 80 comprises: the first triode Q1, the second triode Q2, the first resistance R1, the second resistance R2, the 3rd resistance R3, the 4th resistance R4 and the 4th diode D4, the emitter of described first triode Q1 connects the positive pole of the 3rd diode D3 and one end of the first resistance R1, the base stage of the first triode Q1 connects the other end of the first resistance R1 and one end of the second resistance R2, the other end of described second resistance R2 connects the positive pole of the second diode D2 and the collector electrode of the second triode Q2, the collector electrode of the first triode Q1 connects the positive pole of the diode U2A of the second optocoupler U2 by the 3rd resistance R3, the minus earth of diode U2A, the base stage of the second triode Q2 connects the positive pole of the 4th diode D4, also by the 4th resistance R4 ground connection, the negative pole of the 4th diode D4 connects the output of output rectifier and filter 60, the grounded emitter of the second triode Q2.
Wherein, described 3rd diode D3 and the 4th diode D4 is voltage stabilizing didoe, and described first triode Q1 is PNP triode, and the second triode Q2 is NPN triode.
Please refer to Fig. 1 and Fig. 2, the operation principle of described under-voltage protective switch of the short circuit supply unit is:
During normal work, the first electric capacity C1 is full of electricity by the first diode D1 and the 3rd diode D3.
When occurring that short circuit is abnormal, it is low level that the negative pole of the second diode D2 detects output voltage, and the first electric capacity C19 forms discharge loop by the first resistance R1, the second resistance R2, the second diode D2.Voltage on first electric capacity C19 produces pressure reduction by the first resistance R1, the second resistance R2 dividing potential drop, the base stage making the first triode Q1 and emitter, the first triode Q1 conducting.The loop fast conducting that the diode U2A of the second optocoupler U2 is formed by the first triode Q1 and the 3rd resistance R3, make the triode ON ground connection of the second optocoupler U2, produce low level control pwm control circuit 50 to quit work, stop pwm signal exporting thus stop the output of output voltage.
When occurring that output voltage is under-voltage, 0.7V+ the 3rd diode D3 pressure drop 0.7V falls in the B-E extreme pressure being about 1.4V(first triode Q1 lower than normal voltage as output voltage) more than time, first diode D1, 3rd diode D3, first resistance R1, second resistance R2, conducting loop is formed between second diode D2, make the first triode Q1 conducting, then the diode U2A of the second optocoupler U2 is by the loop fast conducting between the first triode Q1 and the 3rd resistance R3, the triode ON ground connection of the second optocoupler U2, produce low level control pwm control circuit 50 to quit work, thus stop the output of output voltage.
Only have when above-mentioned short circuit or under-voltage abnormal remove after, AC voltage powers on input again, and after switching power unit is restarted, output voltage recovers normally.Like this short circuit or under-voltage time close pwm control circuit and make output voltage stop exporting, abnormal remove after re-power the output just recovering output voltage, the object of available protecting element without damage can be reached.
In the specific implementation; in order to avoid the luminescence of the diode U2A of the base voltage influence of fluctuations second optocoupler U2 of the first triode Q1; described overvoltage crowbar 80 also comprises the second electric capacity C2 and the 5th resistance R5; one end of described second electric capacity C2 connects the base stage of the first triode Q1; the other end ground connection of the second electric capacity C2; one end of 5th resistance R5 is connected the positive pole of the diode U2A of the second optocoupler U2, is also connected the collector electrode of the first triode Q1 by the 3rd resistance R3, the other end ground connection of the 5th resistance R5.
In order to stablize base stage and the emitter pressure reduction of the first triode Q1, protect the first triode Q1, described overvoltage crowbar 80 also comprises the 4th electric capacity C4, and described 4th electric capacity C4 is in parallel with the first resistance R1.
In order to stablize the base voltage of the second triode Q2; described overvoltage crowbar 80 also comprises the 6th resistance R6 and the 5th electric capacity C5; one end of described 6th resistance R6 connects the positive pole of the 4th diode D4; the other end of the 6th resistance R6 connect the second triode Q2 base stage, also by the 4th resistance R4 ground connection; one end of described 5th electric capacity C5 connects the base stage of the second triode Q2, the other end ground connection of the 5th electric capacity C5.
In sum, the under-voltage protective switch of the short circuit supply unit that the utility model provides detects the under-voltage of output voltage or short circuit exception by increasing under-voltage short-circuit protection circuit, the triggered voltage protection circuit when there is under-voltage or short circuit, loop is formed with overvoltage crowbar, the second optocoupler conducting is made to produce low level to close pwm control circuit, thus under-voltage or short circuit is abnormal time stop the output of output voltage, achieve quick protection that is under-voltage or short circuit, ensure that the reliability of the under-voltage of high-peak power power-supply system or short-circuit protection, its circuit is simple and reliable, cost is extremely low, be easy to batch production and quality control, improve product quality.
Be understandable that; for those of ordinary skills; can be equal to according to the technical solution of the utility model and utility model design thereof and replace or change, and all these change or replace the protection range that all should belong to the claim appended by the utility model.
Claims (8)
1. a under-voltage protective switch of the short circuit supply unit; comprise AC voltage input circuit, EMI circuit, input rectifying filter circuit, power switch circuit, pwm control circuit, output rectifier and filter, feedback control circuit, high-frequency isolation transformer, the first optocoupler, the second optocoupler; it is characterized in that, also comprise:
The under-voltage short-circuit protection circuit of triggered voltage protection circuit during for detecting output voltage under-voltage or short circuit;
During for being triggered and under-voltage short-circuit protection circuit form loop, make the second optocoupler conducting produce low level to close pwm control circuit, to stop the overvoltage crowbar of output of output voltage;
Described AC voltage input circuit, EMI circuit, input rectifying filter circuit connects successively, described input rectifying filter circuit connects power switch circuit, pwm control circuit and high-frequency isolation transformer, described power switch circuit connects pwm control circuit and high-frequency isolation transformer, described pwm control circuit connects high-frequency isolation transformer, first optocoupler U1 and the second optocoupler U2, described first optocoupler connects feedback control circuit, second optocoupler connects overvoltage crowbar, output rectifier and filter connects high-frequency isolation transformer, interface, feedback control circuit, overvoltage crowbar and under-voltage short-circuit protection circuit, described overvoltage crowbar connects under-voltage short-circuit protection circuit.
2. under-voltage protective switch of the short circuit supply unit according to claim 1, is characterized in that, described under-voltage short-circuit protection circuit comprises the first diode, the second diode, the 3rd diode and the first electric capacity; The positive pole of described first diode connects the output of output rectifier and filter and the negative pole of the second diode; the negative pole of described first diode connects the negative pole of the 3rd diode; the positive pole of the 3rd diode connects overvoltage crowbar, also by the first capacity earth, the positive pole of described second diode connects overvoltage crowbar.
3. under-voltage protective switch of the short circuit supply unit according to claim 2, it is characterized in that, described overvoltage crowbar comprises: the first triode, the second triode, the first resistance, the second resistance, the 3rd resistance, the 4th resistance and the 4th diode, the emitter of described first triode connects the positive pole of the 3rd diode and one end of the first resistance, the base stage of the first triode connects the other end of the first resistance and one end of the second resistance, the other end of described second resistance connects the positive pole of the second diode and the collector electrode of the second triode, the collector electrode of the first triode connects the positive pole of the diode of the second optocoupler by the 3rd resistance, the minus earth of the diode of the second optocoupler, the base stage of the second triode connects the positive pole of the 4th diode, also by the 4th grounding through resistance, the negative pole of the 4th diode connects the output of output rectifier and filter, the grounded emitter of the second triode.
4. under-voltage protective switch of the short circuit supply unit according to claim 3; it is characterized in that; described overvoltage crowbar also comprises the second electric capacity and the 5th resistance; one end of described second electric capacity connects the base stage of the first triode; the other end ground connection of the second electric capacity; one end of 5th resistance is connected the positive pole of the diode of the second optocoupler, is also connected the collector electrode of the first triode by the 3rd resistance, the other end ground connection of the 5th resistance.
5. under-voltage protective switch of the short circuit supply unit according to claim 3, is characterized in that, described overvoltage crowbar also comprises the 4th electric capacity, described 4th electric capacity and the first resistor coupled in parallel.
6. under-voltage protective switch of the short circuit supply unit according to claim 3; it is characterized in that; described overvoltage crowbar also comprises the 6th resistance and the 5th electric capacity; one end of described 6th resistance connects the positive pole of the 4th diode; the other end of the 6th resistance connect the second triode base stage, also by the 4th grounding through resistance; one end of described 5th electric capacity connects the base stage of the second triode, the other end ground connection of the 5th electric capacity.
7. under-voltage protective switch of the short circuit supply unit according to claim 2, is characterized in that, described 3rd diode employing model is 1N4148, pressure drop is the voltage stabilizing didoe of 0.7V.
8. under-voltage protective switch of the short circuit supply unit according to claim 3, is characterized in that, described 4th diode is voltage stabilizing didoe, and described first triode is PNP triode, and the second triode is NPN triode.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420747192.8U CN204258271U (en) | 2014-12-03 | 2014-12-03 | A kind of under-voltage protective switch of the short circuit supply unit |
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| CN201420747192.8U CN204258271U (en) | 2014-12-03 | 2014-12-03 | A kind of under-voltage protective switch of the short circuit supply unit |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104811026A (en) * | 2015-05-27 | 2015-07-29 | 成都德麦科技有限公司 | Switch power supply |
| CN106786374A (en) * | 2017-02-21 | 2017-05-31 | 广东欧珀移动通信有限公司 | Power circuit, linear power supply and audio frequency apparatus |
| CN107465352A (en) * | 2017-09-11 | 2017-12-12 | 沈阳铁路信号有限责任公司 | Five tunnels export microcomputer monitoring Switching Power Supply |
| CN107750083A (en) * | 2017-11-23 | 2018-03-02 | 广东新昇电业科技股份有限公司 | A kind of four-in-one light modulation protection circuit and its method |
| CN108418186A (en) * | 2018-05-08 | 2018-08-17 | 广州金升阳科技有限公司 | A kind of under-voltage and short-circuit protection circuit of output |
| CN109980954A (en) * | 2019-04-15 | 2019-07-05 | 苏州沙丘电子科技有限公司 | Switching power circuit |
| CN112881764A (en) * | 2021-03-18 | 2021-06-01 | 中煤科工集团西安研究院有限公司 | Mining power supply load side short circuit/undervoltage detection protection circuit and method |
-
2014
- 2014-12-03 CN CN201420747192.8U patent/CN204258271U/en active Active
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104811026A (en) * | 2015-05-27 | 2015-07-29 | 成都德麦科技有限公司 | Switch power supply |
| CN106786374A (en) * | 2017-02-21 | 2017-05-31 | 广东欧珀移动通信有限公司 | Power circuit, linear power supply and audio frequency apparatus |
| CN107465352A (en) * | 2017-09-11 | 2017-12-12 | 沈阳铁路信号有限责任公司 | Five tunnels export microcomputer monitoring Switching Power Supply |
| CN107750083A (en) * | 2017-11-23 | 2018-03-02 | 广东新昇电业科技股份有限公司 | A kind of four-in-one light modulation protection circuit and its method |
| CN108418186A (en) * | 2018-05-08 | 2018-08-17 | 广州金升阳科技有限公司 | A kind of under-voltage and short-circuit protection circuit of output |
| CN109980954A (en) * | 2019-04-15 | 2019-07-05 | 苏州沙丘电子科技有限公司 | Switching power circuit |
| CN109980954B (en) * | 2019-04-15 | 2020-07-14 | 苏州沙丘电子科技有限公司 | Switching power supply circuit |
| CN112881764A (en) * | 2021-03-18 | 2021-06-01 | 中煤科工集团西安研究院有限公司 | Mining power supply load side short circuit/undervoltage detection protection circuit and method |
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