CN202737449U - Multi-path output power protection circuit and electronic equipment - Google Patents
Multi-path output power protection circuit and electronic equipment Download PDFInfo
- Publication number
- CN202737449U CN202737449U CN 201220408516 CN201220408516U CN202737449U CN 202737449 U CN202737449 U CN 202737449U CN 201220408516 CN201220408516 CN 201220408516 CN 201220408516 U CN201220408516 U CN 201220408516U CN 202737449 U CN202737449 U CN 202737449U
- Authority
- CN
- China
- Prior art keywords
- circuit
- electric power
- output electric
- reference voltage
- output power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
The utility model relates to the field of electronic circuits and provides a multi-path output power protection circuit and electronic equipment. The multi-path output power protection circuit comprises multi-path output power supplies, a transformer, a reference voltage comparison circuit, an isolation feedback circuit, a control chip and a switch tube. The multi-path output power supplies comprise a main input power supply and a plurality of auxiliary output power supplies. The main output power supply comprises a closed-loop feedback circuit. Each auxiliary output power supply comprises a control switch and an output voltage connected with the reference voltage comparison circuit so as to control the reference voltage comparison circuit. According to the technical scheme of the utility model, the multi-path output power protection circuit solves the problem that the accurate voltage cannot be provided due to the occupation of a larger feedback quantity during the short-circuit protection of multi-path output power supplies.
Description
Technical field
The utility model relates to a kind of power circuit, is specifically related to a kind of multiple-output electric power protective circuit.
Background technology
At present, the AC-DC(that is directly connected to AC network exchanges input direct-current output) multiple-output electric power is widely used in the various electronic products products such as television set, DVD, set-top box.In the product practical application; owing to various unpredictable reasons, when being connected to the load abnormal short circuit of power output end, light then cause burning out of equipment and power supply; heavy then cause that fire causes serious consequence, so can power supply realize that short-circuit protection seems particularly important.
Existing a kind of multiple-output electric power protective circuit as shown in Figure 1 comprises two-way out-put supply Vout1, Vout2 among Fig. 1, wherein Vout1 has connected a upper sample resistance R1, and the R1 parallel connection diode D3; Similarly, out-put supply Vout2 has connected a upper sample resistance R3, and the R3 parallel connection diode D4, described upper sample resistance R1, R3 all connects with lower sample resistance R4, goes up like this sample resistance R1, R3, and diode D3, D4 and lower sample resistance R4 have consisted of sampling microwave network.
When normal operation, upper sample resistance R1, R3 upper diode D3, D4 reverse voltage in parallel are higher than forward voltage, do not participate in work, upper sample resistance R1, R3 and lower sample resistance R4 form one to the dividing potential drop sampling of output voltage, compare with the N3 internal comparator, reach the brightness of control optocoupler N2 interior light emitting diodes, thereby control N2 receives the purpose of N1 FB pin voltage, and N1 comes opening of control switch pipe Q1 by modes such as duty ratio or ON time and ends, and reaches the stable of control output voltage.But when the Vout1 output short-circuit, at this moment diode D3 negative pole is equivalent to ground connection, at this moment diode D3 forward conduction.The voltage of the sampling end of N3 has just become the conduction voltage drop of diode; because the conducting voltage of diode is far smaller than the reference voltage (2.5V or 1.25V) of N3; therefore; the N3 conducting diminishes or turn-offs; the LED electric current of optocoupler N2 inside diminishes or turn-offs like this, and FB pin voltage raises, thereby control chip N1 just is judged as short circuit; and then control switch pipe Q1 shutoff, power supply enters guard mode.Similarly, the Vout2 short path principle also is the same.
If but output voltage is expanded several roads again; 5 tunnel outputs such as Fig. 2; each road out-put supply all uses the method for Fig. 1 to use the method for sampling resistor and switching diode parallel connection; although solved the problem of short-circuit protection; but taken feedback quantity; caused the greatly reduction of output voltage precision; and it is well-known; multiple-output electric power can require directly to CPU or SDR(Double Data Rate synchronous DRAM) or the FLASH(flash memory) power supply; require the precision of output voltage very high, therefore use aforesaid way will make output voltage not reach requirement.
Summary of the invention
The purpose of this utility model is to provide a kind of multiple-output electric power protective circuit, and the problem of accurate voltage can't be provided because taking larger feedback quantity when being intended to solve the multiple-output electric power short-circuit protection.
The utility model provides a kind of multiple-output electric power protective circuit, and multiple-output electric power comprises main road out-put supply and a plurality of bypass out-put supply; Transformer is connected with described multiple-output electric power; The reference voltage comparison circuit comprises three terminal regulator; Isolation feedback circuit is connected with the reference voltage comparison circuit; Control chip is connected with isolation feedback circuit; Switching tube is connected with control chip, and wherein control chip is used for the conducting of control switch pipe and closes; Wherein every road bypass out-put supply includes control switch and is connected in series mutually with three terminal regulator in the reference voltage comparison circuit, is used for the output voltage of control reference voltage comparison circuit.
More excellent, the control switch of described every road bypass out-put supply is diode.
More excellent, described main road out-put supply also comprises closed-loop feedback circuit, described closed-loop feedback circuit comprises sample resistance and lower sample resistance, and the three terminal regulator phase in described lower sample resistance and the reference voltage comparison circuit also connects, and be in series with upper sample resistance.
More excellent, diode and lower sample resistance in the bypass out-put supply of described every road are in series.
More excellent, described isolation feedback circuit is optocoupler, described optocoupler comprises Light-Emitting Diode and illuminated triode.
More excellent, described Light-Emitting Diode is connected with the reference voltage comparison circuit, and the described light triode that is subjected to is connected with control chip.
More excellent, described switching tube comprises field effect transistor.
The utility model also provides a kind of electronic equipment, has adopted this multiple-output electric power protective circuit.
A kind of multiple-output electric power protective circuit that adopts the utility model embodiment to provide; when power supply is short-circuited; because the bypass out-put supply does not adopt as closed-loop feedback circuit of the prior art, and can take less feedback quantity, thereby the higher voltage of output prograin.
Description of drawings
Fig. 1 is the circuit diagram of a kind of multiple-output electric power protective circuit of providing of prior art;
Fig. 2 is the concrete expansion of the existing multiple-output electric power protective circuit among Fig. 1;
Fig. 3 is the framework schematic diagram of a kind of multiple-output electric power protective circuit of providing of the utility model embodiment;
Fig. 4 is the physical circuit figure of a kind of multiple-output electric power protective circuit of providing of the utility model embodiment;
Fig. 5 is the internal structure schematic diagram of three terminal regulator in the reference voltage comparison circuit that provides of the utility model embodiment.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explaining the utility model, and be not used in restriction the utility model.
Must understand the technical solution of the utility model for better, the applicant illustrates the protective circuit of this multiple-output electric power by the schematic block diagram of Fig. 3.As shown in Figure 3, a kind of multichannel output protection power supply block diagram, comprising a main road output 1 and a plurality of bypass output 2-N, transformer is connected benchmark comparison circuit, isolation feedback circuit, control chip and switching tube with multichannel output.Wherein main road output 1 is with the protective circuit of the closed loop feedback of sample resistance; and each road auxiliary output 2-N all has a controlled switch; wherein the controlled switch of the closed-loop feedback circuit of main road output 1 and bypass output all is connected with the benchmark comparison circuit; the benchmark comparison circuit then is connected with isolation feedback circuit; and isolation feedback circuit is connected with control chip, and control chip then is connected with switching tube.When a certain bypass output is short-circuited; the controlled switch that links to each other with bypass output has been controlled the output voltage of benchmark comparison circuit; by the protection of isolation feedback circuit triggering control chip, come control switch pipe to close by control chip this moment, reaches the purpose of short-circuit protection.
As shown in Figure 4, Fig. 4 has showed a kind of embodiment of multiple-output electric power protective circuit, is more clear explanation the technical solution of the utility model, specifies as an example of Fig. 4 specific implementation example:
Fig. 4 has showed three road out-put supply Vout1, Vout2, Vout3, and wherein Vout1 is main road output, and Vout2 and Vout3 then are auxiliary output.Wherein, main road output Vout1 is connected with upper sample resistance R6, and it is in parallel that upper sample resistance R6 and capacitor C 4 are carried out, and Vout2 links to each other with diode D1, and Vout3 then is connected with diode D2.In addition, R6, D1 and the D2 formation sample circuit of all connecting with lower sample resistance R10.
In addition; this multiple-output electric power protective circuit also comprises the reference voltage comparison circuit; this reference voltage comparison circuit is by three terminal regulator U1; resistance R 11 and capacitor C 1 form; wherein resistance R 11 is in series with capacitor C 1; and U1 is in parallel with three terminal regulator, and the REF pin (see figure 5) among the three terminal regulator U1 in the described reference voltage comparison circuit is connected with above-mentioned sample circuit.Wherein three terminal regulator U1 can adopt three end adjustable shunt reference source TL431 or the TL432 with good thermal stability that Texas Instrument produces.Because this device is existing components and parts, its concrete operation principle is not repeated herein.
In addition, this multiple-output electric power protective circuit also comprises optocoupler, and described optocoupler comprises Light-Emitting Diode U2-A and is subjected to light triode U2-B, control chip U3 and switching tube Q2.CATHODE pin among the three terminal regulator U1 in described Light-Emitting Diode U2-A and the reference voltage comparison circuit link to each other (seeing Fig. 5), control chip U3 then links to each other with the U2-B of illuminated triode, and control chip U3 links to each other with switching tube Q2 and is used for conducting and the shutoff of control switch pipe Q2.Described switching tube can be field effect transistor, and described optocoupler, control chip and switching tube are all the available circuit components and parts, are not repeated herein.
Specific works process of the present utility model and short-circuit protection operation principle are as follows:
1) when input powers on, power supply enters the electrifying startup process, and output voltage raises gradually, and this moment, control chip U3 FB pin level allowed to keep the high voltage of certain hour, and the power supply feedback control loop can normally be set up.
2) output voltage is received three terminal regulator U1 after upper sample resistance R6, lower sample resistance R10 dividing potential drop, compare with U1 internal reference voltage, thereby control U1 output end voltage, make the curent change that flows through on the optocoupler U2 light-emitting diode U2-A, reach the variation of control optocoupler U2 interior light emitting diodes U2-A luminosity, make the illuminated triode U2-B change in voltage that connects control chip U3 FB pin, control chip U3 comes control switch pipe Q2 by the variation of the change in voltage control GATE pin duty ratio of FB pin, makes the power-supply system steady operation.
3) take Vout2 as example; when the power supply output loading is short-circuited; voltage difference drags down (being equivalent to ground connection); namely be that diode D1 negative electrode is pulled down near 0V; the anode potential of D1 is clamped at (less than 0.7V) in the diode current flow pressure drop; the voltage that namely is U1 sampling end is pulled low to less than 0.7V); (for example be far smaller than the reference voltage of benchmark comparison circuit inside; the reference voltage of TL431 is 2.495V, and the reference voltage of TL432 is 1.25V), U1 internal comparator output low level; inner triode conducting is turn-offed; light-emitting diode among the optocoupler U2 does not have electric current to flow through, and then U3 FB pin is high potential, after the suitable time-delay of chip; the chip trigger protection; control switch pipe Q2 closes, and enters guard mode, and system works is in guard mode (have the hiccups or lock).After short-circuit condition was removed, system entered starting state, then again enters steady operation.
4) the FB pin voltage system of this protected mode control chip U3 is the same with single channel or main road protected mode; can find out by Fig. 5; TL431 as benchmark and comparison circuit; when the voltage of its REF pin (accessing the sample circuit) is short-circuited near the 0V(main road; the dividing potential drop of upper sample resistance R6 and lower sample resistance R10 is near 0V) time; inner REF voltage is higher than REF pin voltage; comparator output electronegative potential; the inner triode cut-off of TL431; make the inner LED of light-emitting diode U2-A of the optocoupler that is connected to its CATHODE pin not have electric current to flow through; the light triode U2-B that is subjected to of optocoupler ends; the FB pin of control chip U3 is high potential, after the suitable time-delay of chip U3, and the chip trigger protection; control switch pipe Q1 closes, and enters guard mode.So the scheme protected mode can be reliable and stable work
A kind of multiple-output electric power protective circuit that adopts the utility model embodiment to provide; when power supply is short-circuited; because the bypass out-put supply does not adopt as closed-loop feedback circuit of the prior art, and can take less feedback quantity, thereby the higher voltage of output prograin.
The utility model also provides a kind of electronic equipment, comprises having used above-mentioned multiple-output electric power protective circuit, because it is used in operation principle in the electronic equipment with above-mentioned consistent, just repeats no more herein.Described electronic equipment is, but is not limited to set-top box or digital TV integrated machine or network protocol television.
The above only is preferred embodiment of the present utility model; not in order to limit the utility model; all any modifications of within spirit of the present utility model and principle, doing, be equal to and replace and improvement etc., all should be included within the protection range of the present utility model.
Claims (8)
1. multiple-output electric power protective circuit comprises:
Multiple-output electric power comprises main road out-put supply and a plurality of bypass out-put supply;
Transformer is connected with described multiple-output electric power;
The reference voltage comparison circuit comprises three terminal regulator;
Isolation feedback circuit is connected with the reference voltage comparison circuit;
Control chip is connected with isolation feedback circuit;
Switching tube is connected with control chip, and wherein control chip is used for the conducting of control switch pipe and closes;
It is characterized in that:
Every road bypass out-put supply includes control switch and is connected in series mutually with three terminal regulator in the reference voltage comparison circuit, is used for the output voltage of control reference voltage comparison circuit.
2. multiple-output electric power protective circuit as claimed in claim 1 is characterized in that, the control switch of described bypass out-put supply is diode.
3. multiple-output electric power protective circuit as claimed in claim 2; it is characterized in that; described main road out-put supply also comprises closed-loop feedback circuit; described closed-loop feedback circuit comprises sample resistance and lower sample resistance; three terminal regulator phase in described lower sample resistance and the described reference voltage comparison circuit also connects, and be in series with upper sample resistance.
4. multiple-output electric power protective circuit as claimed in claim 3 is characterized in that, diode and described lower sample resistance in the bypass out-put supply of described every road are in series.
5. multiple-output electric power protective circuit as claimed in claim 1 is characterized in that, described isolation feedback circuit comprises optocoupler, and described optocoupler comprises Light-Emitting Diode and illuminated triode.
6. multiple-output electric power protective circuit as claimed in claim 5 is characterized in that, described Light-Emitting Diode is connected with described reference voltage comparison circuit, and the described light triode that is subjected to is connected with described control chip.
7. multiple-output electric power protective circuit as claimed in claim 1 is characterized in that, described switching tube comprises field effect transistor.
8. an electronic equipment is characterized in that, comprises the described multiple-output electric power protective circuit of claim 1-7 any one.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220408516 CN202737449U (en) | 2012-08-17 | 2012-08-17 | Multi-path output power protection circuit and electronic equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220408516 CN202737449U (en) | 2012-08-17 | 2012-08-17 | Multi-path output power protection circuit and electronic equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202737449U true CN202737449U (en) | 2013-02-13 |
Family
ID=47663111
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220408516 Expired - Fee Related CN202737449U (en) | 2012-08-17 | 2012-08-17 | Multi-path output power protection circuit and electronic equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202737449U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021128716A1 (en) * | 2019-12-26 | 2021-07-01 | 上海派能能源科技股份有限公司 | Multiplexed output short-circuit protection circuit |
-
2012
- 2012-08-17 CN CN 201220408516 patent/CN202737449U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021128716A1 (en) * | 2019-12-26 | 2021-07-01 | 上海派能能源科技股份有限公司 | Multiplexed output short-circuit protection circuit |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103023320B (en) | High-efficiency bidirectional direct current converter and control method thereof | |
| CN103269548A (en) | LED drive circuit system, controller and control method | |
| CN103917012B (en) | A kind of white LED driver system with under-voltage locking and overheat protector module | |
| CN102570785A (en) | Direct-current power supply hot plug slow starting control circuit and control method | |
| CN204681253U (en) | A kind of electric power system and LED power | |
| CN103079322B (en) | Closed loop light-emitting diode (LED) current control circuit and power-switching circuit | |
| CN103917011B (en) | A kind of white LED driver system with soft-start module | |
| CN104768303A (en) | Led drive control circuit | |
| CN106558980A (en) | It is a kind of to enable control circuit | |
| CN204031553U (en) | A kind of LED drive circuit and soft starting circuit thereof | |
| CN203645858U (en) | Step-down control chip, step-down LED drive circuit and display screen | |
| CN202696122U (en) | Short-circuit protection circuit of multiplexed output power and electronic equipment | |
| CN202737449U (en) | Multi-path output power protection circuit and electronic equipment | |
| CN104023445B (en) | A kind of LED drive circuit | |
| CN205051402U (en) | Lithium batteries control circuit | |
| CN102694471A (en) | Auxiliary power supply system for photovoltaic inverter | |
| CN204557272U (en) | Automobile voltage-stabilized power supply circuit | |
| CN103337841A (en) | Bidirectional current limiter based on bidirectional BUCK converter and bidirectional current limiting method thereof | |
| CN202524600U (en) | Buck LED constant current drive control circuit | |
| CN202455282U (en) | Multi-output power supply with auxiliary output voltage stabilizing circuit | |
| CN108933517A (en) | The output voltage feed circuit and temperature-compensation circuit of switch converters | |
| CN201682667U (en) | Control circuit for automatically tracking driving voltage of LED | |
| CN203279299U (en) | Led drive circuit system and controller | |
| CN104184128A (en) | Battery discharge protection method and circuit and lamp thereof | |
| CN103327697B (en) | Drive circuit and light emitting device |
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: 20130213 Termination date: 20150817 |
|
| EXPY | Termination of patent right or utility model |