CN201860084U - Short-circuit protection circuit of single-stage power factor correction circuit - Google Patents
Short-circuit protection circuit of single-stage power factor correction circuit Download PDFInfo
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- CN201860084U CN201860084U CN2010205884025U CN201020588402U CN201860084U CN 201860084 U CN201860084 U CN 201860084U CN 2010205884025 U CN2010205884025 U CN 2010205884025U CN 201020588402 U CN201020588402 U CN 201020588402U CN 201860084 U CN201860084 U CN 201860084U
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- power factor
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Abstract
The utility model relates to a short-circuit protection circuit of a single-stage power factor correction circuit, comprising a power factor correction circuit voltage output primary terminal T, a control chip U1 and a protection device, wherein the protection device comprises diodes D15, D17 and D3, resistors R10, R11 and R12 and triodes Q3 and Q20; cathode terminals of the diodes D15 and D17 are connected with the voltage output primary terminal T, an anode terminal of the diode D17 is connected with the resistor R10 which is connected with the base of the triode Q3, and the anode terminal of the diode D15 is connected with an emitter of the Q3, the resistor 11 is connected between the base and the collector of the triode Q3; and a base of the triode Q3 is further connected to a VCC (virtual channel connection) pin of the control chip U1; the resistor R12 is connected between the base of the triode Q3 and the emitter of the triode Q20; and the base of the triode Q20 is connected with the collector of the triode Q3, and the diode D3 is connected with the collector of the triode Q20 and the zero current detection terminal of the control chip U1. The short-circuit protection circuit has the advantages of simple circuit structure, low cost, high practicality and high reliability.
Description
Technical field
The utility model relates to circuit, relates in particular to a kind of short-circuit protection circuit of single-stage power factor correcting circuit.
Background technology
In recent years, LED has entered lighting field, as architectural lighting.Street lighting, Landscape Lighting, Sign Board, signal lamps etc. are used more and more widely.It is various that the topological structure of driving power has become; The kind of power supply requirement and function are also more and more.Along with various countries are more and more higher to the requirement of power factor, single-stage flyback power factor correcting circuit drives in the LED illumination and becomes more and more popular.Sort circuit is simple because of circuit, and cost is low, and power factor is high and popular, but this circuit also has than obvious defects, and one of them is difficult to secondary short circuited is carried out the effective circuit protection exactly.
The utility model content
The utility model provides a kind of short-circuit protection circuit of single-stage power factor correcting circuit at the above-mentioned defective of prior art, so that secondary short circuited is effectively protected, guarantees the safety of circuit.
In order to solve the problems of the technologies described above, the utility model is achieved through the following technical solutions:
A kind of short-circuit protection circuit of single-stage power factor correcting circuit; circuit of power factor correction voltage output primary side T; control chip U1 and protective device; described protective device comprises diode D15; D17; D3; resistance R 10; R11; R12; triode Q3; Q20; diode D15 wherein; the D17 cathode terminal is connected with voltage output primary side T; the anode tap of D17 connects resistance R 10; resistance R 10 is connected to the base stage of triode Q3; the anode tap of D15 is connected to the emitter of Q3; resistance R 11 is connected between the base stage and collector electrode of Q3; the base stage of described Q3 is also connected to the VCC pin of control chip U1; resistance R 12 is connected between the emitter of the base stage of Q3 and Q20; the base stage of Q20 is connected in the collector electrode of Q3, and diode D3 is connected in the collector electrode of Q20 and the zero current sense terminal of control chip U1.
As can be seen from the above technical solutions, the circuit that the utility model adopts a simple discrete component to form is effectively protected secondary short circuited, effectively guarantees the safety of circuit.It is simple to the utlity model has circuit structure, and cost is low, practical, the advantage that reliability is high.
Description of drawings
Accompanying drawing is the utility model structural representation.
Embodiment
Below in conjunction with embodiment the utility model is described in further detail.
At first define each pin function of control chip U1, U1 the 1st pin is that INV (error amplifier end of oppisite phase input), U1 the 2nd pin are that EA_out (error amplifier output), U1 the 3rd pin are that MULT (multiplier input), U1 the 4th pin are that CS (utilize current sense resistance R s, electric current is changed into the voltage input), U1 the 5th pin are that ZCD (zero current sense terminal), U1 the 6th pin are that GND (earth terminal), U1 the 7th pin are that OUT (input of MOSFET gate drive), U1 the 8th pin are VCC (input service voltage).
Again referring to shown in the accompanying drawing; the short-circuit protection circuit of the utility model single-stage power factor correcting circuit; circuit of power factor correction voltage output primary side T; control chip U1 and protective device; described protective device comprises diode D15; D17; D3; resistance R 10; R11; R12; triode Q3; Q20; diode D15 wherein; the D17 cathode terminal is connected with voltage output primary side T; the anode tap of D17 connects resistance R 10; resistance R 10 is connected to the base stage of triode Q3; the anode tap of D15 is connected to the emitter of Q3; resistance R 11 is connected between the base stage and collector electrode of Q3; the base stage of described Q3 is also connected to the VCC pin of control chip U1; resistance R 12 is connected between the emitter of the base stage of Q3 and Q20; the base stage of Q20 is connected in the collector electrode of Q3, and diode D3 is connected in the collector electrode of Q20 and the zero current sense terminal of control chip U1.
Its operation principle is: when at power work just often, the voltage that diode D15 and D17 negative electrode are born is higher than the voltage that anode bears, and diode D15 and D17 all are in anti-cut-off state partially.Resistance R 10 no currents flow through, not conducting of triode Q3, and the emitter of triode Q20 and base voltage equate that so not conducting of Q20, resistance R 12 and the equal no current of diode D3 flow through.Therefore can not exert one's influence to the 5th pin of control chip U1.If the 5th pin of control chip U1 is subjected to the voltage greater than 5.7V at work, overvoltage protection will take place in control chip U1, turns off the output signal of control chip U1, and control chip U1 quits work, and behind some milliseconds, control chip U1 restarts.Power supply is started working once more.When the power output end short circuit, it is very low that output voltage becomes suddenly, this low pressure is coupled to the accessory power supply winding that the primary side of power supply is provided for control chip U1 work by transformer T1, and the voltage on the accessory power supply winding of primary side also reduces with the voltage of output.The voltage that causes diode D17 negative electrode to be born is lower than the voltage that anode bears, diode D17 conducting, resistance R 10 has electric current to flow through, when resistance R 10 both end voltage differences during greater than 0.7V, triode Q3 conducting, (existence of diode D15 is in order to allow triode Q3 when the power supply operate as normal, and Q3 is in cut-off state).Resistance R 11 has electric current to flow through, when resistance R 11 two ends pressure reduction during greater than 0.7V, and triode Q20 conducting; electric current is by resistance R 12, and triode Q20, diode D3 flow to the 5th pin of control chip U1; the voltage that makes the 5th pin ZCD acceptance is greater than 5.7V; make control chip U1 that overvoltage protection take place, turn off the output signal of control chip U1, control chip U1 quits work behind some milliseconds; restart again; when running into similarity condition, control chip U1 still quits work behind the some milliseconds, restarts again.So just when the power supply output short-circuit, played protection to power circuit.
Above-mentioned specific embodiment is purpose, feature and the effect that is used for describing in detail the utility model, for the personage who is familiar with this type of skill, according to the above description, may do part change and modification to this specific embodiment, its essence does not detach the spiritual category person of the utility model, all should be included in the claim of this case suitable first Chen Ming.
Claims (1)
1. the short-circuit protection circuit of a single-stage power factor correcting circuit; it is characterized in that; circuit of power factor correction voltage output primary side T; control chip U1 and protective device; described protective device comprises diode D15; D17; D3; resistance R 10; R11; R12; triode Q3; Q20; diode D15 wherein; the D17 cathode terminal is connected with voltage output primary side T; the anode tap of D17 connects resistance R 10; resistance R 10 is connected to the base stage of triode Q3; the anode tap of D15 is connected to the emitter of Q3; resistance R 11 is connected between the base stage and collector electrode of Q3; the base stage of described Q3 is also connected to the VCC pin of control chip U1; resistance R 12 is connected between the emitter of the base stage of Q3 and Q20; the base stage of Q20 is connected in the collector electrode of Q3, and diode D3 is connected in the collector electrode of Q20 and the zero current sense terminal of control chip U1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205884025U CN201860084U (en) | 2010-10-29 | 2010-10-29 | Short-circuit protection circuit of single-stage power factor correction circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205884025U CN201860084U (en) | 2010-10-29 | 2010-10-29 | Short-circuit protection circuit of single-stage power factor correction circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201860084U true CN201860084U (en) | 2011-06-08 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010205884025U Expired - Fee Related CN201860084U (en) | 2010-10-29 | 2010-10-29 | Short-circuit protection circuit of single-stage power factor correction circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN201860084U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020073418A1 (en) * | 2018-10-12 | 2020-04-16 | 深圳市华星光电半导体显示技术有限公司 | Input overvoltage protection circuit and power source system |
-
2010
- 2010-10-29 CN CN2010205884025U patent/CN201860084U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020073418A1 (en) * | 2018-10-12 | 2020-04-16 | 深圳市华星光电半导体显示技术有限公司 | Input overvoltage protection circuit and power source 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: 20110608 Termination date: 20111029 |