CN203859489U - Current limiting protection circuit - Google Patents
Current limiting protection circuit Download PDFInfo
- Publication number
- CN203859489U CN203859489U CN201420280312.8U CN201420280312U CN203859489U CN 203859489 U CN203859489 U CN 203859489U CN 201420280312 U CN201420280312 U CN 201420280312U CN 203859489 U CN203859489 U CN 203859489U
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- current
- protection circuit
- limiting protection
- limiting
- triode
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Abstract
The utility model relates to a current limiting protection circuit. The protection circuit comprises a current-limiting resistor Rxa, a first voltage dividing resistor R1, a second voltage dividing resistor R2, a triode T1 and a field effect transistor Q1. The input end of the circuit is connected to the current-limiting resistor Rxa and the emitting electrode of the triode T1. The other end of the current-limiting resistor Rxa is connected to the base electrode of the triode T1. One end of the first voltage dividing resistor R1 is connected to the base electrode of the triode T1. The other end of the first voltage dividing resistor R1 is connected to the collector electrode of the triode T1. The first voltage dividing resistor R1 is further in parallel connection with the field effect transistor Q1, then jointly connected to the second voltage dividing resistor R2, and finally connected to the ground. The current limiting protection circuit utilizes the field effect transistor to achieve disconnection and connection, so as to limit the current. The current limiting protection circuit is simple in structure, low in cost, and substantial in effects after actual usage, and meets the requirements of actual usage.
Description
Technical field
The utility model relates to a kind of current-limiting protection circuit, belongs to circuit protection technical field.
Background technology
Current foldback circuit is an indispensable part in power supply product, roughly can be divided into shutoff mode and current-limiting mode according to its control method.Current-limiting mode is because it has electric current droop characteristic, and after trouble shooting, Switching Power Supply can be resumed work automatically, therefore, obtains applying more widely.First current-limiting protection circuit will have a current sampling link, and at present, general way is small resistor of series connection or obtains current signal with Hall element.In the time that sampling current is smaller, these two kinds of sampling methods are all desirable.But in the time that sampling current is larger, resistance sampling has larger loss, has reduced the efficiency of converter, and that Hall element samples its volume ratio is larger, and expensive, is also a problem to the cost of whole power supply.
Based on above consideration, the utility model proposes a kind of simple and effective current-limiting protection circuit, shortcoming when two kinds of modes sample large electric current more than having overcome.
Utility model content
The deficiency that the utility model exists for prior art just, provides a kind of current-limiting protection circuit.
For addressing the above problem, technical solution adopted in the utility model is as follows:
A kind of current-limiting protection circuit, comprise: current-limiting resistance Rxa, the first divider resistance R1, the second divider resistance R2, triode T1 and field effect transistor Q1, circuit input end connects current-limiting resistance Rxa and triode T1 emitter, the base stage of the other end connecting triode T1 of current-limiting resistance Rxa; First divider resistance R1 one end is connected with the base stage of triode T1, and the collector electrode of other end connecting triode T1 is gone back parallel field effect pipe Q1 on the first divider resistance R1, then connects ground connection after the second divider resistance R2.
As the improvement of technique scheme, after described circuit input end access two diode D1, D2, access again current-limiting protection circuit.
As the improvement of technique scheme, described current-limiting protection circuit also comprises Transient Suppression Diode Z1, Z2, and one end of Transient Suppression Diode Z1, Z2 connects the output of current-limiting protection circuit, other end ground connection.
As the improvement of technique scheme, described current-limiting resistance Rxa is wire-wound resistor.
As the improvement of technique scheme, in described circuit, access two current-limiting protection circuits, and series connection mutually.
Compared with prior art, implementation result of the present utility model is as follows for the utility model:
Current-limiting protection circuit described in the utility model, adopts field effect transistor to realize cut-off and conducting, thereby realizes the current limliting of circuit.This circuit structure is simple, and cost is lower, remarkable by practical effect, meets actual operation requirements.
Brief description of the drawings
Fig. 1 is a kind of current-limiting protection circuit structural representation described in the utility model.
Embodiment
Content of the present utility model is described below in conjunction with specific embodiments.
Be illustrated in figure 1 a kind of current-limiting protection circuit structural representation described in the utility model.A kind of current-limiting protection circuit described in the utility model comprises: current-limiting resistance Rxa, the first divider resistance R1, the second divider resistance R2, triode T1 and field effect transistor Q1; after circuit input end access two diode D1, D2, access again current-limiting protection circuit; circuit input end connects current-limiting resistance Rxa and triode T1 emitter, the base stage of the other end connecting triode T1 of current-limiting resistance Rxa.First divider resistance R1 one end is connected with the base stage of triode T1, and the collector electrode of other end connecting triode T1 is gone back parallel field effect pipe Q1 on the first divider resistance R1, then connects ground connection after the second divider resistance R2.
In order to protect whole circuit, in circuit, access two current-limiting protection circuits, and series connection mutually, as shown in phantom in Figure 1, duplicate protection is provided to so whole circuit.
In circuit, also access is Transient Suppression Diode Z1, Z2, and one end of Transient Suppression Diode Z1, Z2 connects the output of current-limiting protection circuit, other end ground connection.Transient Suppression Diode Z1, Z2 prevent output voltage mutation, and protection load voltage is not subject to the impact of peak voltage, as thunderbolt etc.
Current-limiting resistance Rxa preferably selects wire-wound resistor, reduces the impact of the size of current of temperature on needs restriction, and the bad resistance of temperature coefficient can affect the effect of current limliting.
The current-limiting protection circuit course of work described in the utility model is as follows:
In the time that input current is less than current limliting, current-limiting resistance Rxa both end voltage is less than the cut-in voltage of triode T1, now triode T1 is in cut-off state, input voltage is by the first divider resistance R1, the second divider resistance R2 dividing potential drop, now the source S of field effect transistor Q1 and grid G produce enough pressure reduction, thereby make the conducting of field effect transistor Q1 pipe, circuit is normally worked.
In the time that input current is greater than current limliting, current-limiting resistance Rxa both end voltage is greater than the cut-in voltage of triode T1, now triode T1 is in conducting state, input voltage is just applied directly in the grid G of field effect transistor Q1, now the source S of field effect transistor Q1 and grid G voltage are roughly equal, thereby make field effect transistor Q1 cut-off.Now circuit disconnects, and makes circuit in guard mode, thereby avoids electric current excessive, damages load.
Claims (5)
1. a current-limiting protection circuit, it is characterized in that, comprise: current-limiting resistance Rxa, the first divider resistance R1, the second divider resistance R2, triode T1 and field effect transistor Q1, circuit input end connects current-limiting resistance Rxa and triode T1 emitter, the base stage of the other end connecting triode T1 of current-limiting resistance Rxa; First divider resistance R1 one end is connected with the base stage of triode T1, and the collector electrode of other end connecting triode T1 is gone back parallel field effect pipe Q1 on the first divider resistance R1, then connects ground connection after the second divider resistance R2.
2. a kind of current-limiting protection circuit according to claim 1, is characterized in that, after described circuit input end access two diode D1, D2, accesses current-limiting protection circuit again.
3. a kind of current-limiting protection circuit according to claim 1, is characterized in that, described current-limiting protection circuit also comprises Transient Suppression Diode Z1, Z2, and one end of Transient Suppression Diode Z1, Z2 connects the output of current-limiting protection circuit, other end ground connection.
4. a kind of current-limiting protection circuit according to claim 1, is characterized in that, described current-limiting resistance Rxa is wire-wound resistor.
5. according to arbitrary described a kind of current-limiting protection circuit in claim 1～4, it is characterized in that, in described circuit, access two current-limiting protection circuits, and series connection mutually.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420280312.8U CN203859489U (en) | 2014-05-28 | 2014-05-28 | Current limiting protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420280312.8U CN203859489U (en) | 2014-05-28 | 2014-05-28 | Current limiting protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203859489U true CN203859489U (en) | 2014-10-01 |
Family
ID=51609327
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420280312.8U Expired - Fee Related CN203859489U (en) | 2014-05-28 | 2014-05-28 | Current limiting protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203859489U (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105490621A (en) * | 2015-12-30 | 2016-04-13 | 上海安平静电科技有限公司 | Solar power supply type static electricity detection device |
| CN108233326A (en) * | 2016-12-15 | 2018-06-29 | 重庆川仪自动化股份有限公司 | A kind of current-limiting protection circuit |
| CN108923399A (en) * | 2018-07-02 | 2018-11-30 | 山东航天电子技术研究所 | A kind of recoverable constant current type surge restraint circuit |
| CN109378794A (en) * | 2018-10-18 | 2019-02-22 | 九江精密测试技术研究所 | A kind of protection circuit of fieldbus |
-
2014
- 2014-05-28 CN CN201420280312.8U patent/CN203859489U/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105490621A (en) * | 2015-12-30 | 2016-04-13 | 上海安平静电科技有限公司 | Solar power supply type static electricity detection device |
| CN105490621B (en) * | 2015-12-30 | 2018-04-10 | 上海安平静电科技有限公司 | A kind of solar powered formula electrostatic testing apparatus |
| CN108233326A (en) * | 2016-12-15 | 2018-06-29 | 重庆川仪自动化股份有限公司 | A kind of current-limiting protection circuit |
| CN108923399A (en) * | 2018-07-02 | 2018-11-30 | 山东航天电子技术研究所 | A kind of recoverable constant current type surge restraint circuit |
| CN109378794A (en) * | 2018-10-18 | 2019-02-22 | 九江精密测试技术研究所 | A kind of protection circuit of fieldbus |
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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: 20141001 Termination date: 20160528 |