CN204290699U - A kind of Switching Power Supply protection reference circuit based on TL431 feedback - Google Patents
A kind of Switching Power Supply protection reference circuit based on TL431 feedback Download PDFInfo
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- CN204290699U CN204290699U CN201420773637.XU CN201420773637U CN204290699U CN 204290699 U CN204290699 U CN 204290699U CN 201420773637 U CN201420773637 U CN 201420773637U CN 204290699 U CN204290699 U CN 204290699U
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Abstract
The utility model provides a kind of Switching Power Supply protection reference circuit based on TL431 feedback, be arranged on the reference signal input of the TL431 of Switching Power Supply output protection circuit feedback circuit, for the output protection circuit of Switching Power Supply provides benchmark, comprise electric capacity C1, electric capacity C2, resistance R1, resistance R2, resistance R6 and diode D1; Electric capacity C1 and electric capacity C2 is connected in series between auxiliary electric power supply and ground, and resistance R1 and resistance R2 is connected in series between the V2.5 end of TL431 and ground; One end of resistance R6 is held with the V2.5 of TL431 and is connected, and the other end is connected with the negative electrode of diode D1, and the anode of diode D1 connects the guard signal end of output protection circuit; The tie point of electric capacity C1 and electric capacity C2 and resistance R1 and resistance R2 tie point are connected to form reference signal VREF end.Circuit of the present utility model is simple and reliable, and element is few, and cost is low.
Description
Technical field
The utility model relates to a kind of Switching Power Supply protection reference circuit based on TL431 feedback.
Background technology
TL431 is a kind of accurate voltage-stabilizing device, for the TL431 of Texas Instrument, this TL431 is usually used in the feedback circuit of Switching Power Supply as shown in Figure 1: be that the TL431 of standard adds opto-coupled feedback control circuit, be commonly used on isolation type switching power supply, signal flow gathers output voltage signal by resistance R5 and resistance R6 to follow R (V2.5) pin of TL431 to compare, the AK pin electric current of control TL431 i.e. U1, the On current namely controlling optocoupler U2 regulates the duty ratio of former limit PWM chip, thus reaches the object of automatic voltage regulation.As shown in Figure 2, be a kind of desirable protective circuit, it is by sampling the signal of output current compared with a benchmark Vref, and when the output signal detected is greater than reference signal Vref, operational amplifier exports a protecting control signal.As shown in Figure 2, make a comparison circuit with operational amplifier or comparator exactly, when U3 normal phase input end voltage is higher than inverting input, export high level; Otherwise, when normal phase input end is lower than inverting input, output low level.
At present, based in the Switching Power Supply protection reference circuit of TL431 feedback, reference circuit device excessive cost is too high.
Utility model content
The purpose of this utility model is to provide a kind of Switching Power Supply output protection reference circuit for TL431 feedback; this circuit, when Switching Power Supply output abnormality, can provide reference voltage to protective circuit to overcome the too high problem of the current conventional fiducial circuit devcie excessive cost used.
The utility model for the technical scheme realizing its technical purpose and adopt is: a kind of Switching Power Supply protection reference circuit based on TL431 feedback, be arranged on the reference signal input of the TL431 of Switching Power Supply output protection circuit feedback circuit, for the output protection circuit of Switching Power Supply provides benchmark, it is characterized in that: comprise electric capacity C1, electric capacity C2, resistance R1, resistance R2, resistance R6 and diode D1;
Described electric capacity C1 and electric capacity C2 is connected in series between auxiliary electric power supply and ground, and described resistance R1 and resistance R2 is connected in series between the V2.5 end of TL431 and ground;
One end of resistance R6 is held with the V2.5 of TL431 and is connected, and the other end is connected with the negative electrode of diode D1, and the anode of diode D1 connects the guard signal end of output protection circuit;
Described electric capacity C1 and the tie point of electric capacity C2 and described resistance R1 and resistance R2 tie point are connected to form reference signal VREF end.
Circuit of the present utility model is simple and reliable, and element is few, and cost is low.
Below with reference to drawings and Examples, the utility model is described in detail.
Accompanying drawing explanation
Fig. 1 is power feedback schematic diagram conventional at present.
Fig. 2 is that a kind of desirable power protection signal produces device.
Fig. 3 is the utility model circuit theory diagrams.
Embodiment
Embodiment 1, as shown in Figure 3, the present embodiment is a kind of TL431 feedback switch power protection reference circuit based on Dezhou instrument
A kind of TL431 feedback switch power protection reference circuit specific works process prescription based on Dezhou instrument of the present embodiment: when Switching Power Supply starts, now export and do not set up; Auxiliary power supply is charged to VREF point instantaneous level by electric capacity C1, and output protection circuit can not be protected by mistake.After output is normal, the V2.5 end of U1 has the voltage of a 2.5V, and VREF obtains the benchmark required for a protective circuit by resistance R1 and resistance R2 dividing potential drop; Electric capacity C2 is used for filtering clutter.When output overvoltage or overcurrent and overheat protector sampled voltage reach more than the voltage of VREF; protective circuit can send guard signal; the high level that guard signal is brought is delivered to while V2.5 end (the V2.5 benchmark pin of U1, TL431) controls the PWM chip protection of former limit by diode D1 and resistance R6 and is continued to provide reference voltage to output protection circuit by R1 and R2 dividing potential drop again.
Claims (1)
1. the Switching Power Supply protection reference circuit based on TL431 feedback, be arranged on the reference signal input of the TL431 of Switching Power Supply output protection circuit feedback circuit, for the output protection circuit of Switching Power Supply provides benchmark, it is characterized in that: comprise electric capacity C1, electric capacity C2, resistance R1, resistance R2, resistance R6 and diode D1;
Described electric capacity C1 and electric capacity C2 is connected in series between auxiliary electric power supply and ground, and described resistance R1 and resistance R2 is connected in series between the V2.5 end of TL431 and ground;
One end of resistance R6 is held with the V2.5 of TL431 and is connected, and the other end is connected with the negative electrode of diode D1, and the anode of diode D1 connects the guard signal end of output protection circuit;
Described electric capacity C1 and the tie point of electric capacity C2 and described resistance R1 and resistance R2 tie point are connected to form reference signal VREF end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420773637.XU CN204290699U (en) | 2014-12-10 | 2014-12-10 | A kind of Switching Power Supply protection reference circuit based on TL431 feedback |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420773637.XU CN204290699U (en) | 2014-12-10 | 2014-12-10 | A kind of Switching Power Supply protection reference circuit based on TL431 feedback |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN204290699U true CN204290699U (en) | 2015-04-22 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201420773637.XU Expired - Fee Related CN204290699U (en) | 2014-12-10 | 2014-12-10 | A kind of Switching Power Supply protection reference circuit based on TL431 feedback |
Country Status (1)
| Country | Link |
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| CN (1) | CN204290699U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106160070A (en) * | 2016-06-29 | 2016-11-23 | 无锡蕴能科技有限公司 | Intelligent charger for electric bicycle circuit |
| CN107579648A (en) * | 2017-08-04 | 2018-01-12 | 许继电源有限公司 | A kind of inverse-excitation type switch power-supply and its control circuit |
| CN108494227A (en) * | 2018-04-17 | 2018-09-04 | 深圳市金威源科技股份有限公司 | A kind of Switching Power Supply |
-
2014
- 2014-12-10 CN CN201420773637.XU patent/CN204290699U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106160070A (en) * | 2016-06-29 | 2016-11-23 | 无锡蕴能科技有限公司 | Intelligent charger for electric bicycle circuit |
| CN106160070B (en) * | 2016-06-29 | 2018-12-04 | 无锡蕴能科技有限公司 | Intelligent charger for electric bicycle circuit |
| CN107579648A (en) * | 2017-08-04 | 2018-01-12 | 许继电源有限公司 | A kind of inverse-excitation type switch power-supply and its control circuit |
| CN108494227A (en) * | 2018-04-17 | 2018-09-04 | 深圳市金威源科技股份有限公司 | A kind of Switching Power Supply |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| CP02 | Change in the address of a patent holder | ||
| CP02 | Change in the address of a patent holder |
Address after: 518000 Floors 1-3 and 1-5 of Block A, Block B2, Jinweiyuan Industrial Plant, Longshan District, Pingshan New District, Shenzhen City, Guangdong Province Patentee after: Shenzhen Gold Power Technology Co., Ltd. Address before: 518000 Shenzhen, Guangdong, Pingshan new industrial zone, poly dragon hill area Jinwei Industrial Zone A 1 floor. Patentee before: Shenzhen Gold Power Technology Co., Ltd. |
|
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150422 Termination date: 20181210 |