CN202285320U - Short-circuit protection device for DC low-voltage system - Google Patents
Short-circuit protection device for DC low-voltage system Download PDFInfo
- Publication number
- CN202285320U CN202285320U CN2011203469395U CN201120346939U CN202285320U CN 202285320 U CN202285320 U CN 202285320U CN 2011203469395 U CN2011203469395 U CN 2011203469395U CN 201120346939 U CN201120346939 U CN 201120346939U CN 202285320 U CN202285320 U CN 202285320U
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- circuit
- short
- low
- power supply
- circuit protection
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Abstract
The utility model discloses a short-circuit protection device for a DC low-voltage system, which adopts the structure that an emitting electrode of a PNP-type transistor serves as the input end of a short-circuit protection circuit to be connected with the positive pole of the power supply of the DC low-voltage system; the base electrode of the PNP-type transistor is connected with the collecting electrode of an NPN-type transistor through a resistor; the collecting electrode of the PNP-type transistor is connected with the base electrode of the NPN-type transistor through another resistor; the emitting electrode of the NPN-type transistor is connected with the collecting electrode of the PNP-type transistor through a third resistor; the emitting electrode of the NPN-type transistor is connected with the negative pole of the power supply of the DC low-voltage system to serve as the negative pole of the extra power supply system; and the collecting electrode of the PNP-type transistor serves as the output of the short-circuit protection circuit to power a system requiring extra power supply. Through the short-circuit protection device provided by the utility model, the short-circuit automatic protection for the DC low-voltage is realized, and the power supply for the DC low-voltage system is restored promptly as long as the short circuit disappears.
Description
Technical field
The utility model relates to circuit protection device, is specifically related to the short-circuit protection of a kind of dc low-voltage system.
Background technology
In the application of dc low-voltage system, running into through regular meeting need be to the situation of the extra power supply of accessory circuit.Because a variety of causes is when short circuit appears in accessory circuit, can have a strong impact on the work of main circuit, under the certain situation even can cause main circuit not work or send rub-out signal.
Though general short-circuit protection circuit can be made a response when short circuit takes place rapidly, system is protected,, the reason that causes short circuit can not recover power supply at once automatically after disappearing to the dc low-voltage system.
Summary of the invention
The utility model technical problem to be solved provides the short-circuit protection of a kind of dc low-voltage system; This device can be realized the short circuit of dc low-voltage system is protected automatically, and after the reason that causes short circuit disappears, can recover the power supply to the dc low-voltage system at once.
For realizing the foregoing invention purpose, following technical scheme is adopted in the invention:
The short-circuit protection of a kind of dc low-voltage system; Comprise the protective circuit that transistor and resistance combine; The emitter of a PNP transistor is connected to the positive pole of the power supply of dc low-voltage system as the input of short-circuit protection circuit, and the base stage of PNP transistor connects the collector electrode of NPN transistor through a resistance; The collector electrode of PNP transistor is connected to the base stage of NPN transistor through another one resistance; The emitter of NPN transistor links to each other with the collector electrode of PNP transistor through the 3rd resistance; The emitter of NPN transistor is connected with the negative pole of the power supply of dc low-voltage system, as the negative pole of extra electric power system; The collector electrode of PNP transistor is as the output of short-circuit protection circuit, to system's power supply of the extra power supply of needs.
Be better implement the invention, also comprise indicating circuit, said indicating circuit is divided into output indication and short circuit indication.
Be better implement the invention, the output-parallel of said output indication and short-circuit protection circuit.
Be better implement the invention, said short circuit indication is connected in parallel between the emitter and collector of NPN transistor.
Because adopt aforesaid technical scheme, the invention has following superiority:
Because what this protective circuit adopted is transistor, can realize short-circuit protection,, the reason that causes short circuit can restore electricity rapidly after disappearing.
Description of drawings
Fig. 1 is the circuit theory diagrams of the utility model;
Embodiment
In conjunction with Fig. 1, to the place of the extra power supply of accessory circuit, whether the series connection short-circuit protection indicates short trouble to exist with two LED in the short-circuit protection circuit of this device in the dc low-voltage system.
The accompanying drawing circuit is mainly used in the dc low-voltage system.Transistor T l (SKl00) and T2 (BC547) are used for deriving second 5V voltage (O/P2), are used for the accessory circuit power supply.The circuit working process is: when O/P1 existed, transistor T 2 was through resistance R l, LEDl and R3 conducting, also therefore conducting of transistor T 1 after the conducting, and the output of 5V direct current just can appear at the O/P2 two ends.At this moment green indicating lamp LED2 is luminous, and red led LEDl is idiostatic because of two ends are in, and extinguishes state so still be in.
If the O/P2 failed because, transistor T 2 is owing to base earth ends, thereby Tl also ends.During the O/P2 short circuit, green LED 2 is extinguished, and red LED l is luminous.The C2 at O/P1 two ends and C3 are in order during the O/P2 short circuit, to help to absorb the voltage fluctuation of O/P1, to accomplish the noiseless output of O/P1.The circuit element design is provided by the following relationship formula: R
B=(H
FEXVs)/(1.3xI
L).R in the formula
BBe the base resistance of T1 or T2, H
FEDirect current multiplication factor for T1 or T2 is respectively H
FE=200 (T1) and H
FE=350 (T2).Vs is a switched voltage, is 5V, and 1.3 is coefficient of safety, I
LBe transistorized collection-radio stream.
This device can make under the situation of electric power system failed because owing to a variety of causes at accessory circuit; In time cut off and main circuit is protected the power supply of accessory circuit; After the accessory circuit short trouble is eliminated, can recover power supply automatically simultaneously to accessory circuit.
Claims (4)
1. the short-circuit protection of a dc low-voltage system; It is characterized in that: comprise the protective circuit that transistor and resistance combine; The emitter of a PNP transistor is connected to the positive pole of the power supply of dc low-voltage system as the input of short-circuit protection circuit, and the base stage of PNP transistor connects the collector electrode of NPN transistor through a resistance; The collector electrode of PNP transistor is connected to the base stage of NPN transistor through another one resistance; The emitter of NPN transistor links to each other with the collector electrode of PNP transistor through the 3rd resistance; The emitter of NPN transistor is connected with the negative pole of the power supply of dc low-voltage system, as the negative pole of extra electric power system; The collector electrode of PNP transistor is as the output of short-circuit protection circuit, to system's power supply of the extra power supply of needs.
2. the short-circuit protection of dc low-voltage according to claim 1 system is characterized in that: also comprise indicating circuit, said indicating circuit is divided into the output indication and indicates with short circuit.
3. the short-circuit protection of dc low-voltage according to claim 2 system is characterized in that: the output-parallel of said output indication and short-circuit protection circuit.
4. the short-circuit protection of dc low-voltage according to claim 2 system is characterized in that: said short circuit indication is connected in parallel between the emitter and collector of NPN transistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203469395U CN202285320U (en) | 2011-09-16 | 2011-09-16 | Short-circuit protection device for DC low-voltage system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011203469395U CN202285320U (en) | 2011-09-16 | 2011-09-16 | Short-circuit protection device for DC low-voltage system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202285320U true CN202285320U (en) | 2012-06-27 |
Family
ID=46296831
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011203469395U Expired - Fee Related CN202285320U (en) | 2011-09-16 | 2011-09-16 | Short-circuit protection device for DC low-voltage system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202285320U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103762548A (en) * | 2014-01-13 | 2014-04-30 | 北京恺思维特科技有限责任公司 | Short-circuit protection circuit for low-voltage direct current system |
-
2011
- 2011-09-16 CN CN2011203469395U patent/CN202285320U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103762548A (en) * | 2014-01-13 | 2014-04-30 | 北京恺思维特科技有限责任公司 | Short-circuit protection circuit for low-voltage direct current system |
| CN103762548B (en) * | 2014-01-13 | 2016-04-20 | 北京恺思维特科技有限责任公司 | Short-circuit protection circuit for low-voltage direct current system |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20120627 Termination date: 20130916 |