CN102420421A - Direct-current output short-circuit protection circuit for high-frequency switching power supply - Google Patents
Direct-current output short-circuit protection circuit for high-frequency switching power supply Download PDFInfo
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- CN102420421A CN102420421A CN2011104099775A CN201110409977A CN102420421A CN 102420421 A CN102420421 A CN 102420421A CN 2011104099775 A CN2011104099775 A CN 2011104099775A CN 201110409977 A CN201110409977 A CN 201110409977A CN 102420421 A CN102420421 A CN 102420421A
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Abstract
The invention discloses a direct-current output short-circuit protection circuit for a high-frequency switching power supply and relates to the technical field of the design of direct-current output short-circuit protection circuits for high-frequency switching power supplies. The direct-current output short-circuit protection circuit for the high-frequency switching power supply comprises an alternating-current/direct-current (AC/DC) conversion circuit which is connected to an AC input end, wherein the control input end of the AC/DC conversion circuit is connected with a voltage and current control loop; and a quick DC output short-circuit protection circuit is connected between the voltage signal input end of the voltage and current control loop and the output positive electrode end of the AC/DC conversion circuit. The direct-current output short-circuit protection circuit is designed quickly and works reliably and flexibly, and the property of the high-frequency switching power supply is improved greatly.
Description
Technical field
The present invention relates to the design field of high frequency switch power direct current output short circuit protection circuit.
Background technology
Traditional high frequency switch power direct current output short circuit protection circuit; Mainly form by AC/DC change-over circuit and electric current and voltage control loop; The AC/DC change-over circuit is connected the input of interchange; Control input end at the AC/DC change-over circuit connects the electric current and voltage control loop, and the voltage signal input of electric current and voltage control loop is connected the output cathode end of AC/DC change-over circuit.The major function of electric current and voltage control loop is to detect the power module output current, and when the power module output short-circuit, power module is through Control current loop restriction output current, and the protection power module can not answered the excessive power supply that burns out of short circuit current.Have following shortcoming in the actual use of traditional high frequency switch power direct current output short circuit protection circuit:
1, the circuit protection time slow, burn power module through regular meeting;
2, circuit can only be as overload protection, but as the short-circuit protection less reliable.
Summary of the invention
The object of the invention is to propose the high frequency switch power direct current output short circuit protection circuit of the quick limiting short-circuit current of a kind of ability.
The present invention includes the AC/DC change-over circuit that is connected ac input end; Connect the electric current and voltage control loop in the control input end of AC/DC change-over circuit, be characterized in: between the output cathode end of the voltage signal input of said electric current and voltage control loop and AC/DC change-over circuit, connect quick direct current output short circuit protection circuit.
Quick direct current output short circuit protection circuit according to the invention is made up of voltage comparator circuit and short-circuit protection control circuit; Said voltage comparator circuit is connected the output cathode end of AC/DC change-over circuit; The output of voltage comparator circuit is connected with the input of said short-circuit protection control circuit, and the control output end of short-circuit protection control circuit is connected the voltage signal input of said electric current and voltage control loop.
The present invention is when the dc output end short circuit; The quick quick limiting module output short circuit current of direct current output short circuit protection circuit; Thereby the protection power module is unlikely to output short-circuit and damages, and below power output 3000W, short circuit current is limited in the high frequency switch power AC/DC module of 3 ~ 4A; Can be in short-circuit condition for a long time and do not damage, overcome conventional power source module shortcoming of limiting short-circuit current fast when output short-circuit.The present invention designs fast, reliable operation, and utilization has improved the performance of high frequency switch power flexibly greatly.
The quick direct current output short circuit protection circuit of the present invention mainly is made up of current-limiting resistance, biasing resistor, diode and triode; The negative electrode of said diode connects current-limiting resistance and first biasing resistor, second biasing resistor respectively; The other end of said current-limiting resistance is connected the output cathode end of AC/DC change-over circuit; The other end of said first biasing resistor connects the positive terminal of an accessory power supply, the other end ground connection of said second biasing resistor; The anode of said diode is connected with the base stage of triode, the grounded collector of triode, and the emitter of triode is connected with the voltage signal input of electric current and voltage control loop, between the base stage of the emitter of triode and triode, is connected the 3rd biasing resistor.
In order to improve reliability of the present invention, said diode by at least two in the same way diode connected in parallel form.
Description of drawings
Fig. 1 is a kind of operation principle block diagram of the present invention.
Fig. 2 is the schematic diagram of quick direct current output short circuit protection circuit.
Embodiment
As shown in Figure 1; AC/DC change-over circuit 1 is connected ac power input end; Connect electric current and voltage control loop 2 in the control input end of AC/DC change-over circuit 1, between the output cathode end of the voltage signal input of electric current and voltage control loop 2 and AC/DC change-over circuit 1, connect quick direct current output short circuit protection circuit 3.
As shown in Figure 2, direct current output short circuit protection circuit 3 mainly is made up of current-limiting resistance R1, first group of biasing resistor R2, second group of biasing resistor R3, the 3rd group of biasing resistor R4, two diode D1, D2 and triode Q1 fast.
Two diode D1 and D2 be parallel connection in the same way; The negative electrode of diode D1 and D2 is connected with current-limiting resistance R1 and the first biasing resistor R2, the second biasing resistor R3; The other end of current-limiting resistance R1 is connected the output cathode end V0+ of AC/DC change-over circuit 1; The other end of the first biasing resistor R2 connects the positive terminal VCC+ of an accessory power supply, the other end ground connection of second group of biasing resistor R3.
The anode of diode D1 and D2 is connected with the base stage of triode Q1; The grounded collector of triode Q1; The emitter of triode Q1 is connected with the voltage signal input of electric current and voltage control loop 2, between the base stage of the emitter of triode Q1 and triode Q1, is connected the 3rd biasing resistor R4.
When the dc output end of AC/DC change-over circuit 1 does not have short circuit; Output voltage V 0+ is a normal voltage; Diode D1, D2 cathode potential are higher than anode and are in the anti-phase cut-off state; Triode Q1 does not have base current and is in not on-state, not influence of 3 pairs of electric current and voltage control loops of direct current output short circuit protection circuit 2 fast.
And when the direct current output short-circuit of AC/DC change-over circuit 1; V0+ is 0V; Diode D1, D2 negative electrode also are in conducting state for 0V; Triode Q1 has base current to be in saturation conduction, and the control end through quick direct current output short circuit protection circuit 3 drags down loop voltage rapidly, drags power module away from operating frequency and equals this extremely dangerous working point of resonance frequency.And near short circuit, it is also fast more that VD V0+ descends, and the 3 acting times of direct current output short circuit protection circuit are also short more fast.Experiment shows that direct current output short circuit protection circuit 3 can work fast, thereby effectively reduces short circuit current fast in 1 ~ 2 cycle after short circuit takes place.
Claims (4)
1. high frequency switch power direct current output short circuit protection circuit; Comprise the AC/DC change-over circuit that is connected ac input end; Connect the electric current and voltage control loop in the control input end of AC/DC change-over circuit, it is characterized in that between the output cathode end of the voltage signal input of said electric current and voltage control loop and AC/DC change-over circuit, connecting quick direct current output short circuit protection circuit.
2. according to the said high frequency switch power direct current of claim 1 output short circuit protection circuit; It is characterized in that said quick direct current output short circuit protection circuit is made up of voltage comparator circuit and short-circuit protection control circuit; Said voltage comparator circuit is connected the output cathode end of AC/DC change-over circuit; The output of voltage comparator circuit is connected with the input of said short-circuit protection control circuit, and the control output end of short-circuit protection control circuit is connected the voltage signal input of said electric current and voltage control loop.
3. according to the said high frequency switch power direct current of claim 2 output short circuit protection circuit; It is characterized in that said quick direct current output short circuit protection circuit mainly is made up of current-limiting resistance, biasing resistor, diode and triode; The negative electrode of said diode connects current-limiting resistance and first biasing resistor, second biasing resistor respectively; The other end of said current-limiting resistance is connected the output cathode end of AC/DC change-over circuit; The other end of said first biasing resistor connects the positive terminal of an accessory power supply, the other end ground connection of said second biasing resistor; The anode of said diode is connected with the base stage of triode, the grounded collector of triode, and the emitter of triode is connected with the voltage signal input of electric current and voltage control loop, between the base stage of the emitter of triode and triode, is connected the 3rd biasing resistor.
4. according to the said high frequency switch power direct current of claim 2 output short circuit protection circuit, it is characterized in that said diode by at least two in the same way diode connected in parallel form.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104099775A CN102420421A (en) | 2011-12-12 | 2011-12-12 | Direct-current output short-circuit protection circuit for high-frequency switching power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104099775A CN102420421A (en) | 2011-12-12 | 2011-12-12 | Direct-current output short-circuit protection circuit for high-frequency switching power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102420421A true CN102420421A (en) | 2012-04-18 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011104099775A Pending CN102420421A (en) | 2011-12-12 | 2011-12-12 | Direct-current output short-circuit protection circuit for high-frequency switching power supply |
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| CN (1) | CN102420421A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05252735A (en) * | 1992-03-05 | 1993-09-28 | Matsushita Electric Ind Co Ltd | Power circuit |
| JPH1169818A (en) * | 1997-08-11 | 1999-03-09 | Nec Corp | Method and apparatus for short circuit protection of power circuit and power circuit provided with function of short circuit protection |
| CN2660754Y (en) * | 2003-11-28 | 2004-12-01 | 海信集团有限公司 | Mains protective circuit of household electrical appliances |
-
2011
- 2011-12-12 CN CN2011104099775A patent/CN102420421A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05252735A (en) * | 1992-03-05 | 1993-09-28 | Matsushita Electric Ind Co Ltd | Power circuit |
| JPH1169818A (en) * | 1997-08-11 | 1999-03-09 | Nec Corp | Method and apparatus for short circuit protection of power circuit and power circuit provided with function of short circuit protection |
| CN2660754Y (en) * | 2003-11-28 | 2004-12-01 | 海信集团有限公司 | Mains protective circuit of household electrical appliances |
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Application publication date: 20120418 |