CN201860094U - Short circuit protection circuit for switch power - Google Patents
Short circuit protection circuit for switch power Download PDFInfo
- Publication number
- CN201860094U CN201860094U CN2010206123873U CN201020612387U CN201860094U CN 201860094 U CN201860094 U CN 201860094U CN 2010206123873 U CN2010206123873 U CN 2010206123873U CN 201020612387 U CN201020612387 U CN 201020612387U CN 201860094 U CN201860094 U CN 201860094U
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- circuit
- capacitor
- resistance
- pwm
- pnp
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Abstract
The utility model discloses a short circuit protection circuit for the switch power, which comprises an optical coupler IC1, resistors R1, R2, RT, a capacitor C1, a transistor PNP, wherein one end of the resistor R1 is connected with the emitter of the transistor PNP and the pin 8 of the PWM chip Vref, the other end of the resistor R1 is connected with one end of the optical coupler IC1 and the base of the transistor PNP, and is connected with one end of the capacitor C1 through the resistor R2. The other end of the capacitor C1 is earthed, and the collector of the transistor PNP is connected with the pin 4 of the PWM chip R/C. According to the utility model, a transistor on/off circuit driven by the protecting optical coupling is added into the PWM oscillator circuit. When the over current occurs or short shirt protection starts in the conventional circuit, the oscillator circuit is shut down at the same time, so that the effect of better closing the PWM is achieved.
Description
Technical field
The utility model relates to a kind of Switching Power Supply short-circuit protection circuit.
Background technology
General inverse-excitation type switch power-supply, when overcurrent or short circuit, the electric current on the former limit of transformer increases, the voltage increases on sampling resistor or the former limit of instrument transformer, duty ratio increases gradually, and when the CS of PWM voltage surpasses 1V, PWM closes and quits work.This mode of stopping of closing is very single, and function is not strong.
The utility model content
The utility model technical issues that need to address provide a kind of enhancement mode Switching Power Supply short-circuit protection circuit, when overcurrent protection in the traditional circuit or short guarantor, oscillating circuit is turn-offed simultaneously, thereby reach the effect of better closing PWM.
For addressing the above problem; technical solution adopted in the utility model is: a kind of Switching Power Supply short-circuit protection circuit; comprise optocoupler IC1; resistance R 1, R2, RT, capacitor C 1, triode PNP; wherein an end of resistance R 1 connects the emitter of triode PNP and 8 pin Vref of PWM chip; the end of resistance R 1 another termination optocoupler IC1 and the base stage of triode PNP; and connect an end of capacitor C 1 by resistance R 2; capacitor C 1 other end ground connection, the collector electrode of triode PNP meet 4 pin R/C of PWM chip by resistance R T.
Adopt the beneficial effect that technique scheme produced to be: this novel triode conducting cut-off circuit that in the PWM oscillating circuit, adds by the driving of protection optocoupler; when overcurrent protection in the traditional circuit or short guarantor; oscillating circuit is turn-offed simultaneously, thereby reach the effect of better closing PWM.
Description of drawings
Fig. 1 is the utility model schematic diagram.
Embodiment
Below in conjunction with accompanying drawing the utility model is done and to be described in further detail: as shown in Figure 1, this novel optocoupler IC1 that comprises, resistance R 1, R2, RT, capacitor C 1, triode PNP, wherein an end of resistance R 1 connects the emitter of triode PNP and 8 pin Vref of PWM chip, the end of resistance R 1 another termination optocoupler IC1 and the base stage of triode PNP, and pass through the end that resistance R 2 connects capacitor C 1, and capacitor C 1 other end ground connection, the collector electrode of triode PNP meets 4 pin R/C of PWM chip by resistance R T.
Operation principle:
When output short-circuit; optocoupler disconnects; the difference of the 8 pin Vref level of the base stage level of triode PNP and PWM is less than the junction voltage of triode; cause triode PNP to be in cut-off state; disconnect PWM oscillation resistance RT, thereby make the PWM nonoscillatory, play a protective role; resistance R 2, capacitor C 1 form the transistor base supply network, better play a protective role.
Claims (1)
1. Switching Power Supply short-circuit protection circuit; it is characterized in that: comprise optocoupler IC1; resistance R 1, R2, RT, capacitor C 1, triode PNP; wherein an end of resistance R 1 connects the emitter of triode PNP and 8 pin Vref of PWM chip; the end of resistance R 1 another termination optocoupler IC1 and the base stage of triode PNP; and pass through the end that resistance R 2 connects capacitor C 1, and capacitor C 1 other end ground connection, the collector electrode of triode PNP meets 4 pin R/C of PWM chip by resistance R T.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206123873U CN201860094U (en) | 2010-11-18 | 2010-11-18 | Short circuit protection circuit for switch power |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010206123873U CN201860094U (en) | 2010-11-18 | 2010-11-18 | Short circuit protection circuit for switch power |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201860094U true CN201860094U (en) | 2011-06-08 |
Family
ID=44105893
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010206123873U Expired - Fee Related CN201860094U (en) | 2010-11-18 | 2010-11-18 | Short circuit protection circuit for switch power |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201860094U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103928909A (en) * | 2014-02-28 | 2014-07-16 | 深圳市伟创电气有限公司 | Quick and reliable short-circuit protection method and circuit of switch power supply |
| WO2016090547A1 (en) * | 2014-12-09 | 2016-06-16 | 深圳市聚作照明股份有限公司 | Switch-mode power supply and short-circuit protection circuit thereof |
| CN108337768A (en) * | 2017-12-28 | 2018-07-27 | 宁波丽安电子有限公司 | A kind of the PFC constant-current driving power supplies circuit and control method of double protections |
| CN110739665A (en) * | 2019-09-10 | 2020-01-31 | 科华恒盛股份有限公司 | Protection circuit and switching power supply |
| CN110854818A (en) * | 2019-12-13 | 2020-02-28 | 东莞市动力之星电子有限公司 | Power supply short-circuit protection circuit with near zero power consumption |
-
2010
- 2010-11-18 CN CN2010206123873U patent/CN201860094U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103928909A (en) * | 2014-02-28 | 2014-07-16 | 深圳市伟创电气有限公司 | Quick and reliable short-circuit protection method and circuit of switch power supply |
| CN103928909B (en) * | 2014-02-28 | 2016-08-24 | 深圳市伟创电气有限公司 | The short-circuit protection method of Switching Power Supply fast and reliable and circuit |
| WO2016090547A1 (en) * | 2014-12-09 | 2016-06-16 | 深圳市聚作照明股份有限公司 | Switch-mode power supply and short-circuit protection circuit thereof |
| CN108337768A (en) * | 2017-12-28 | 2018-07-27 | 宁波丽安电子有限公司 | A kind of the PFC constant-current driving power supplies circuit and control method of double protections |
| CN110739665A (en) * | 2019-09-10 | 2020-01-31 | 科华恒盛股份有限公司 | Protection circuit and switching power supply |
| CN110739665B (en) * | 2019-09-10 | 2022-03-11 | 科华恒盛股份有限公司 | Protection circuit and switching power supply |
| CN110854818A (en) * | 2019-12-13 | 2020-02-28 | 东莞市动力之星电子有限公司 | Power supply short-circuit protection circuit with near zero power consumption |
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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: 20110608 Termination date: 20141118 |
|
| EXPY | Termination of patent right or utility model |