CN204696663U - A kind of efficient output short circuit protection circuit - Google Patents
A kind of efficient output short circuit protection circuit Download PDFInfo
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- CN204696663U CN204696663U CN201520265260.1U CN201520265260U CN204696663U CN 204696663 U CN204696663 U CN 204696663U CN 201520265260 U CN201520265260 U CN 201520265260U CN 204696663 U CN204696663 U CN 204696663U
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Abstract
The utility model provides a kind of efficient output short circuit protection circuit, comprise: the first bleeder circuit, second bleeder circuit, reference voltage circuit and comparator, the output connecting valve electric power output voltage of described first bleeder circuit and the second bleeder circuit, the output of described first bleeder circuit connects the electrode input end of comparator, the output of described second bleeder circuit connects the negative input of described comparator, the output of described comparator connects PWM controller, the electrode input end of described comparator arranges biasing resistor, described biasing resistor is connected with described reference voltage circuit, described reference voltage circuit is connected with the output of described comparator.The utility model realizes fast, efficient detection output short-circuit state, greatly shortens the protective reaction time, guarantees that equipment can not damage in the short-circuit state, ensure the safe operation of equipment.
Description
Technical field
The utility model relates to a kind of protective circuit, is specifically related to a kind of efficient output short circuit protection circuit, and the output voltage being adapted to Switching Power Supply is high, electric current large, power reaches a few hectowatt even to the circuit output short circuit protection of tens kilowatts.
Background technology
In fields such as industry automatic control, to have efficiency high, lightweight because of it for Switching Power Supply, and the advantages such as volume is little are widely used.Stability and the reliability of Switching Power Supply are even more important, and require that failure rate is extremely low simultaneously.Several protective circuit just must be had for improving stability and the reliability of Switching Power Supply in powerful Switching Power Supply.Particularly in communication, the fields such as the charging module in electric power system, such as electric automobile and charging pile, output short-circuit (overcurrent) protection of Switching Power Supply is the function of crucial importance ensureing electronic product security reliability.If Switching Power Supply, when output short-circuit (overcurrent), will produce huge electric current to semiconductor power device, thus burn out power device.
Traditional overcurrent for Switching Power Supply, output short circuit protection mode, as depicted in figs. 1 and 2.By arranging current transformer T1, detect the electric current passed through in the full-bridge working method be made up of elements such as triode Q1, triode Q2, triode Q3, triode Q4, transformer T2.Through A, B point output output short-circuit (overcurrent) protecting control signal of current transformer T1, Switching Power Supply is protected, avoids burning out power device.
Above-mentioned traditional Switching Power Supply protected mode due to the reaction time long; effectively can not protect in real time, protection point voltage value can not be selected simultaneously accurately, chosen little and can produce protection by mistake; choose greatly and can not effectively play a protective role, to electronic product protectiveness poor.
Utility model content
In order to overcome above-mentioned prior art Problems existing; the utility model provides a kind of efficient output short circuit protection circuit; solve above-mentioned prior art because the reaction time is long, can not select the problem of protection magnitude of voltage accurately; realize quick, efficient detection output short-circuit state; greatly shorten the protective reaction time; guarantee that equipment can not damage in the short-circuit state, ensure the safe operation of equipment.
The technical solution of the utility model is: a kind of efficient output short circuit protection circuit, comprise: the first bleeder circuit, second bleeder circuit, reference voltage circuit and comparator, the output connecting valve electric power output voltage of described first bleeder circuit and the second bleeder circuit, the output of described first bleeder circuit connects the electrode input end of comparator, the output of described second bleeder circuit connects the negative input of described comparator, the output of described comparator connects PWM controller, the electrode input end of described comparator arranges biasing resistor, described biasing resistor is connected with described reference voltage circuit, described reference voltage circuit is connected with the output of described comparator.
Further, described first bleeder circuit comprises resistance R1, resistance R2, resistance R3, resistance R7 and electric capacity C1, described resistance R1, resistance R2 and resistance R3 series connection is linked into the electrode input end of described comparator, described resistance R7 is connected with the electrode input end of described comparator with one end after electric capacity C1 parallel connection, other end ground connection; Described second bleeder circuit comprises resistance R4, resistance R5, resistance R6, resistance R8 and electric capacity C2, described resistance R4, resistance R5 and resistance R6 series connection is linked into the negative input of described comparator, described resistance R8 is connected with the negative input of described comparator with one end after electric capacity C2 parallel connection, other end ground connection.
Further, described resistance R1 is equal with resistance R4, and resistance R2 is equal with resistance R5, and resistance R3 is equal with resistance R6, and resistance R7 is equal with resistance R8, and the capacitance of described electric capacity C1 is at least less than 1/10 of the capacitance of electric capacity C2.
Further, described reference voltage circuit comprises voltage-stabiliser tube D1 and resistance R10, the negative pole of described voltage-stabiliser tube D1 is connected to the earth terminal of electric capacity C1, one end of the positive pole contact resistance R10 of described voltage-stabiliser tube D1, the other end of described resistance R10 connects one end of pull-up resistor R11, and the other end of described pull-up resistor R11 connects the output of described comparator.
Further, one end of described biasing resistor R9 connects the electrode input end of described comparator, and the other end connects the positive pole of voltage-stabiliser tube D1.
Further, described comparator adopts LM293 comparator.
The beneficial effects of the utility model are: the short-circuit protection circuit that the utility model provides realizes fast, efficient detection output short-circuit state; greatly shorten the protective reaction time; thus effectively protect power device and electronic product; guarantee that equipment can not damage in the short-circuit state, ensure the safe operation of equipment.
Accompanying drawing explanation
Fig. 1 is a kind of structure chart of traditional output short circuit protection circuit described in the utility model;
Fig. 2 is the another kind of structure chart of traditional output short circuit protection circuit described in the utility model;
Fig. 3 is the efficient output short circuit protection circuit structured flowchart of one that the utility model proposes;
Fig. 4 is the efficient output short circuit protection circuit structure chart of one that the utility model proposes.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in detail.
See Fig. 3 and Fig. 4, wherein Fig. 3 is the efficient output short circuit protection circuit structured flowchart of one that the utility model proposes; Fig. 4 is the efficient output short circuit protection circuit structure chart of one that the utility model proposes.
As shown in Figure 3 and Figure 4, a kind of efficient output short circuit protection circuit, comprise: the first bleeder circuit, second bleeder circuit, reference voltage circuit and comparator, the output connecting valve electric power output voltage of described first bleeder circuit and the second bleeder circuit, the output of described first bleeder circuit connects the electrode input end of comparator, the output of described second bleeder circuit connects the negative input of described comparator, the output of described comparator connects PWM controller, the electrode input end of described comparator arranges biasing resistor, described biasing resistor is connected with described reference voltage circuit, described reference voltage circuit is connected with the output of described comparator.
Further, described first bleeder circuit comprises resistance R1, resistance R2, resistance R3, resistance R7 and electric capacity C1, described resistance R1, resistance R2 and resistance R3 series connection is linked into the electrode input end of described comparator, described resistance R7 is connected with the electrode input end of described comparator with one end after electric capacity C1 parallel connection, other end ground connection; Described second bleeder circuit comprises resistance R4, resistance R5, resistance R6, resistance R8 and electric capacity C2, described resistance R4, resistance R5 and resistance R6 series connection is linked into the negative input of described comparator, described resistance R8 is connected with the negative input of described comparator with one end after electric capacity C2 parallel connection, other end ground connection.
Further, described resistance R1 is equal with resistance R4, and resistance R2 is equal with resistance R5, and resistance R3 is equal with resistance R6, and resistance R7 is equal with resistance R8, and the capacitance of described electric capacity C1 is at least less than 1/10 of the capacitance of electric capacity C2.
Further, described reference voltage circuit comprises voltage-stabiliser tube D1 and resistance R10, the negative pole of described voltage-stabiliser tube D1 is connected to the earth terminal of electric capacity C1, one end of the positive pole contact resistance R10 of described voltage-stabiliser tube D1, the other end of described resistance R10 connects one end of pull-up resistor R11, and the other end of described pull-up resistor R11 connects the output of described comparator.
Further, one end of described biasing resistor R9 connects the electrode input end of described comparator, and the other end connects the positive pole of voltage-stabiliser tube D1.
Further, described comparator adopts LM293 comparator.
In the utility model embodiment, described biasing resistor R9 resistance is selected at the magnitude of voltage of transcient short circuit time voltage drop according to when exporting, and can select protection magnitude of voltage accurately, control precision is high, avoids and protects by mistake or protect problem not in place.
In the utility model embodiment; VCC+ is the output voltage of Switching Power Supply, and VDD is the operating voltage of protective circuit, is obtained by the pull-up resistor R11 of the output of comparator; reference voltage is 5.1V, and the output of comparator U1 outputs signal to control circuit for closing PWM.The output voltage of Switching Power Supply supplies the electrode input end of comparator U1 by the first bleeder circuit, by the negative input of the second bleeder circuit supply comparator U1, make the electrode input end voltage of comparator be greater than the negative input voltage of comparator by the biasing resistor R9 arranging the electrode input end of comparator, now the output of comparator U1 exports high level.When the output of Switching Power Supply has short circuit, the output voltage of Switching Power Supply just has a drop-out voltage value, the now voltage of the electrode input end of the comparator U1 drop-out voltage value that just has one to suddenly change, because the capacitance of electric capacity C2 is much larger than the capacitance of electric capacity C1, decline moment at the output voltage of Switching Power Supply, the size that magnitude of voltage on electric capacity C1 declines is much larger than the voltage on electric capacity C2, now the voltage of the electrode input end of comparator is lower than the voltage of the negative input of comparator, and the output of comparator U1 exports a low level signal and closes PWM to control section.
The short-circuit protection circuit that the utility model provides realizes fast, efficient detection output short-circuit state; greatly shorten the protective reaction time; thus effectively protect power device and electronic product, guarantee that equipment can not damage in the short-circuit state, ensure the safe operation of equipment.
Above the utility model is described in detail, but the utility model is not limited to above-mentioned execution mode, in the ken that those of ordinary skill in the art possess, can also makes a variety of changes under the prerequisite not departing from the utility model aim.Do not depart from design of the present utility model and scope can make many other and change and remodeling.Should be appreciated that the utility model is not limited to specific execution mode, scope of the present utility model is defined by the following claims.
Claims (6)
1. an efficient output short circuit protection circuit, it is characterized in that, comprise: the first bleeder circuit, second bleeder circuit, reference voltage circuit and comparator, the output connecting valve electric power output voltage of described first bleeder circuit and the second bleeder circuit, the output of described first bleeder circuit connects the electrode input end of comparator, the output of described second bleeder circuit connects the negative input of described comparator, the output of described comparator connects PWM controller, the electrode input end of described comparator arranges biasing resistor, described biasing resistor is connected with described reference voltage circuit, described reference voltage circuit is connected with the output of described comparator.
2. the efficient output short circuit protection circuit of one according to claim 1, it is characterized in that, described first bleeder circuit comprises resistance R1, resistance R2, resistance R3, resistance R7 and electric capacity C1, described resistance R1, resistance R2 and resistance R3 series connection is linked into the electrode input end of described comparator, described resistance R7 is connected with the electrode input end of described comparator with one end after electric capacity C1 parallel connection, other end ground connection; Described second bleeder circuit comprises resistance R4, resistance R5, resistance R6, resistance R8 and electric capacity C2, described resistance R4, resistance R5 and resistance R6 series connection is linked into the negative input of described comparator, described resistance R8 is connected with the negative input of described comparator with one end after electric capacity C2 parallel connection, other end ground connection.
3. the efficient output short circuit protection circuit of one according to claim 2; it is characterized in that; described resistance R1 is equal with resistance R4; resistance R2 is equal with resistance R5; resistance R3 is equal with resistance R6; resistance R7 is equal with resistance R8, and the capacitance of described electric capacity C1 is at least less than 1/10 of the capacitance of electric capacity C2.
4. the efficient output short circuit protection circuit of one according to claim 2; it is characterized in that; described reference voltage circuit comprises voltage-stabiliser tube D1 and resistance R10; the negative pole of described voltage-stabiliser tube D1 is connected to the earth terminal of electric capacity C1; one end of the positive pole contact resistance R10 of described voltage-stabiliser tube D1; the other end of described resistance R10 connects one end of pull-up resistor R11, and the other end of described pull-up resistor R11 connects the output of described comparator.
5. the efficient output short circuit protection circuit of one according to claim 4, is characterized in that, one end of described biasing resistor R9 connects the electrode input end of described comparator, and the other end connects the positive pole of voltage-stabiliser tube D1.
6. the efficient output short circuit protection circuit of one according to claim 5, is characterized in that, described comparator adopts LM293 comparator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520265260.1U CN204696663U (en) | 2015-04-28 | 2015-04-28 | A kind of efficient output short circuit protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520265260.1U CN204696663U (en) | 2015-04-28 | 2015-04-28 | A kind of efficient output short circuit protection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN204696663U true CN204696663U (en) | 2015-10-07 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520265260.1U Expired - Fee Related CN204696663U (en) | 2015-04-28 | 2015-04-28 | A kind of efficient output short circuit protection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106410757A (en) * | 2016-10-10 | 2017-02-15 | 许继电源有限公司 | Short-circuit protective circuit |
-
2015
- 2015-04-28 CN CN201520265260.1U patent/CN204696663U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106410757A (en) * | 2016-10-10 | 2017-02-15 | 许继电源有限公司 | Short-circuit protective circuit |
| CN106410757B (en) * | 2016-10-10 | 2019-05-24 | 许继电源有限公司 | A kind of short-circuit protection circuit |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20151007 Termination date: 20160428 |