CN202424107U - Over-current protection circuit and player - Google Patents
Over-current protection circuit and player Download PDFInfo
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- CN202424107U CN202424107U CN201120538954.XU CN201120538954U CN202424107U CN 202424107 U CN202424107 U CN 202424107U CN 201120538954 U CN201120538954 U CN 201120538954U CN 202424107 U CN202424107 U CN 202424107U
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Abstract
The utility model discloses an over-current protection circuit and a player. The over-current protection circuit comprises a voltage input end, a voltage output end, a main system circuit, a switch circuit, an over-current adjustment circuit and a feedback circuit, wherein the switch circuit is used for controlling the voltage output state of the over-current protection circuit; the over-current adjustment circuit is used for adjusting an over-current protection point of the over-current protection circuit; and the feedback circuit is used for monitoring the current size of the voltage output end. The utility model has the advantages that the problem about over-current protection of an output interface of the player is well solved, cost is reduced, and the over-current protection point of the output interface of the player can be flexibly adjusted according to different output requirements of the output interface of the player, so the application range of the over-current protection circuit is expanded.
Description
Technical field
The utility model relates to the current protection technology field of circuit, relates in particular to a kind of current foldback circuit and player.
Background technology
In the prior art, adopt special-purpose overcurrent protection chip to realize overcurrent protection usually to USB/HDMI output interface in the player.Yet the price of this overcurrent protection chip is very high, and when the current foldback circuit of design player output interface, can only select a kind of overcurrent protection chip.Just select the over-current protection point of player output interface and selected the overcurrent protection chip, thereby made player output interface current foldback circuit of the prior art can not adjust its over-current protection point neatly.
The utility model content
The main purpose of the utility model provides current foldback circuit and the player that a kind of cost is low and can adjust flexibly over-current protection point.
In order to achieve the above object; The utility model proposes a kind of current foldback circuit; Comprise voltage input end, voltage output end and main system circuit, also comprise switching circuit, overcurrent adjustment circuit and feedback circuit, said switching circuit is used to control the voltage output state of said current foldback circuit; Said overcurrent adjustment circuit is used to adjust the over-current protection point of said current foldback circuit, and said feedback circuit is used to monitor the size of current of said voltage output end.
Preferably; Said overcurrent adjustment circuit comprises first resistance, second resistance, the 3rd resistance, the 4th resistance, the 9th resistance and the tenth resistance; After said first resistance, second resistance, the 3rd resistance and the 4th resistance are parallel with one another; The one of which common ends is connected with said switching circuit, and another common ends is connected with said voltage output end, is connected between said voltage output end and the ground after said the 9th resistance and the tenth resistance are connected each other.
Preferably; Said switching circuit comprises the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, first triode and second triode; Be connected in after said the 5th resistance and said the 6th resistance are parallel with one another between the collector electrode of base stage and said second triode of said first triode; The emitter of said first triode is connected with said voltage input end; The collector electrode of said first triode is connected with said overcurrent adjustment circuit; The base stage of said second triode is connected with the over-current signal detection pin of said main system circuit and an end of said the 7th resistance respectively through said the 8th resistance, and the other end of said the 7th resistance is connected with said voltage input end, and the emitter of said second triode is connected with ground.
Preferably; Said feedback circuit comprises the 11 resistance, the 12 resistance, electric capacity, the 3rd triode and the 4th triode; The base stage of said the 3rd triode is connected with said overcurrent adjustment circuit through said the 11 resistance; Be connected between said voltage input end and the ground after said the 12 resistance and said electric capacity are connected each other, the collector electrode of said the 3rd triode is connected between said the 12 resistance and the said electric capacity, and the emitter of said the 3rd triode is connected with ground; The base stage of said the 4th triode is connected with ground through said electric capacity, and the collector electrode of said the 4th triode detects pin with the over-current signal of said main system circuit and is connected.
Preferably, the collector electrode of first triode first resistance, second resistance, the 3rd resistance and the 4th resistance in said overcurrent adjustment circuit is connected with said voltage output end in the said switching circuit.
Preferably, the base stage of the 3rd triode is connected in the said overcurrent adjustment circuit between the 9th resistance and said the tenth resistance through said the 11 resistance in the said feedback circuit.
Preferably, said first triode is the PNP triode, and said second triode, the 3rd triode and the 4th triode are NPN utmost point pipe.
The utility model also proposes a kind of player, comprises output interface, and said output interface comprises above-mentioned current foldback circuit.
Preferably, said output interface comprises USB output interface and HDMI output interface.
The current foldback circuit that the utility model proposes; Adopt the combination of gadgets such as resistance, electric capacity and triode to replace the overcurrent protection chip of player output interface current foldback circuit in the prior art; Not only well solved the overcurrent protection problem of player output interface; Also reduced cost; And the utility model can also require the over-current protection point of its output interface is adjusted flexibly according to the difference output of player output interface, thereby has enlarged the range of application of this current foldback circuit.
Description of drawings
Fig. 1 is the schematic block circuit diagram of the utility model current foldback circuit preferred embodiment;
Fig. 2 is the electrical block diagram of the utility model current foldback circuit preferred embodiment.
The realization of the utility model purpose, functional characteristics and advantage will combine embodiment, further specify with reference to accompanying drawing.
Embodiment
Further specify the technical scheme of the utility model below in conjunction with Figure of description and specific embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the utility model, and be not used in qualification the utility model.
With reference to Fig. 1, Fig. 1 is the schematic block circuit diagram of the utility model current foldback circuit preferred embodiment, comprises voltage input end 1, switching circuit 2, overcurrent adjustment circuit 3, voltage output end 4, feedback circuit 5 and main system circuit 6.
Wherein, switching circuit 2 is connected between voltage input end 1 and the overcurrent adjustment circuit 3, and overcurrent adjustment circuit 3 also is connected with voltage output end 4 and feedback circuit 5 respectively, and feedback circuit 5 also is connected with main system circuit 6 and switching circuit 2 respectively.
Concrete; Switching circuit 2 is used to control the voltage output state of this current foldback circuit; When the output current value of the voltage output end 4 of this current foldback circuit is excessive, during promptly greater than preset over-current protection point, the voltage output of then turn-offing this current foldback circuit; When the output current value of the voltage output end of this current foldback circuit during, then let this current foldback circuit be in normal output voltage state less than preset over-current protection point; Overcurrent adjustment circuit 3 is used to adjust the over-current protection point of this current foldback circuit; Feedback circuit 5 is used to monitor the output current size of the voltage output end 4 of this current foldback circuit; The output current that monitors voltage output end 4 when feedback circuit 5 is during greater than preset over-current protection point; Feedback circuit 5 control switch circuit 2 are off state; Make switching circuit 2 turn-off the voltage output of the utility model current foldback circuit; The output current that monitors voltage output end 4 when feedback circuit 5 is during less than preset over-current protection point, and feedback circuit 5 control switch circuit 2 are conducting state, make the utility model current foldback circuit be in normal output voltage state.
With reference to Fig. 2; Fig. 2 is the electrical block diagram of the utility model current foldback circuit preferred embodiment; Comprise switching circuit 2, overcurrent adjustment circuit 3, feedback circuit 5; VCC representes the input voltage of voltage input end among the figure, and VO representes the output voltage of voltage output end, and PCOHD representes that the over-current signal of main system circuit detects pin.
Wherein overcurrent adjustment circuit 3 comprises first resistance R 1, second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 9th resistance R 9 and the tenth resistance R 10; Wherein first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 parallel with one another after; The one of which common ends is connected with switching circuit 2; Another common ends is connected with voltage output end; And the end after the 9th resistance R 9 and the 10 mutual series connection of the tenth resistance R is connected with voltage output end, and the other end after the 9th resistance R 9 and the tenth resistance R 10 are connected each other is connected with ground.
Switching circuit 2 comprises the 5th resistance R 5, the 6th resistance R 6, the 7th resistance R 7, the 8th resistance R 8, the first triode Q1 and the second triode Q2, and the first triode Q1 is the PNP triode, and the second triode Q2 is the NPN triode.Wherein the 5th resistance R 5 and the 6th resistance R 6 are connected in after parallel with one another between the collector electrode of base stage and the second triode Q2 of the first triode Q1; The emitter of the first triode Q1 is connected with voltage input end, and first resistance R 1 of the collector electrode of the first triode Q1 in overcurrent adjustment circuit 3, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 are connected with voltage output end.The base stage of the second triode Q3 is connected with the over-current signal detection pin PCOHD of main system circuit and an end of the 7th resistance R 7 respectively through the 8th resistance R 8, and the other end of the 7th resistance R 7 is connected with voltage input end, and the emitter of the second triode Q2 is connected with ground.
Feedback circuit 5 comprises the 11 resistance R the 11, the 12 resistance R 12, capacitor C 1, the 3rd triode Q3 and the 4th triode Q4, and the 3rd triode Q3 and the 4th triode Q4 are the NPN triode.Wherein the base stage of the 3rd triode Q3 is connected in the overcurrent adjustment circuit 3 between the 9th resistance R 9 and the tenth resistance R 10 through the 11 resistance R 11; The 12 resistance R 12 and capacitor C 1 are connected between voltage input end and the ground after the series connection each other; The collector electrode of the 3rd triode Q3 is connected between the 12 resistance R 12 and the capacitor C 1; The emitter of the 3rd triode Q3 is connected with ground; The base stage of the 4th triode Q4 is connected with ground through capacitor C 1, and the collector electrode of the 4th triode Q4 detects pin PCOHD with the over-current signal of main system circuit and is connected.
The default over-current protection point of present embodiment is 1.1A, and its operation principle is following:
When the circuit powered on moment; The input voltage VCC of voltage input end gives capacitor C 1 charging through the 12 resistance R 12, and the base stage of powered on moment the 4th triode Q4 that makes at circuit is in low level, thereby the 4th triode Q4 ends; Thereby make that the over-current signal detection pin PCOHD of main system circuit is a high level; Thereby the second triode Q2 conducting, the first triode Q1 saturation conduction, thus voltage output end is in normal output voltage state.Present embodiment is because the existence of capacitor C 1 has avoided circuit powered on moment the 4th triode Q4 to shift to an earlier date conducting and the second triode Q2 is ended than the 3rd triode Q3, thereby the problem that the first triode Q1 is closed takes place.
When circuit powers on its output normal electrical flow valuve of back; Be that output current is during less than 500mA; Circuit through the dividing potential drop of first resistance R 1 parallel with one another, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 and dividing potential drop through the 9th resistance R 9 of series connection each other and the 11 resistance R 11 after, make base stage and the voltage between the emitter of the 3rd triode Q3 greater than 0.7V, thereby make the 3rd triode Q3 saturation conduction; Thereby the base stage of the collector electrode of the 3rd triode Q3 and the 4th triode Q4 is low level; Thereby make the 4th triode Q4 end, thereby make that the over-current signal detection pin PCOHD of main system circuit is a high level, thereby the second triode Q2 conducting; The first triode Q1 saturation conduction; Thereby the voltage output end of circuit is in normal output voltage state, and it is high level that while main system circuit is investigated its over-current signal detection pin PCOHD, so the main system circuit knows that the voltage output end of this current foldback circuit is in normal output voltage state.
When its output current value is excessive after circuit powers on; Be that output current value is when surpassing the default over-current protection point 1.1A of present embodiment; Circuit through the dividing potential drop of first resistance R 1 parallel with one another, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 and dividing potential drop through the 9th resistance R 9 of series connection each other and the 11 resistance R 11 after; Make base stage and the voltage between its emitter of the 3rd triode Q3 less than 0.7V, thereby make the 3rd triode Q3 end, the 4th triode Q4 saturation conduction; Thereby make that the over-current signal detection pin PCOHD of main system circuit is a low level; Thereby the second triode Q2 ends, and the first triode Q1 closes, thereby has turn-offed the voltage output of circuit; It is low level that while main system circuit is investigated its over-current signal detection pin PCOHD, so the main system circuit knows that this current foldback circuit is in the overcurrent protection state.
The adjustment principle of the over-current protection point of the utility model current foldback circuit is following: after circuit powers on; When if its output current value surpasses the default over-current protection point 1.1A of this utility model embodiment; Circuit is lower than 4.75V through the voltage after partial of first resistance R 1 parallel with one another, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4, and the voltage of this 4.75V is again after the dividing potential drop through the 9th resistance R 9 and the 11 resistance R 11, makes base stage and the voltage between its emitter of the 3rd triode Q3 less than 0.7V; Thereby make the 3rd triode Q3 end; The 4th triode Q4 saturation conduction, thus make that the over-current signal detection pin PCOHD of main system circuit is a low level, thus the second triode Q2 ends; The first triode Q1 closes, thereby has turn-offed the voltage output of circuit.If the voltage before first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 is 5V; And the parallelly connected resistance of first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 is 0.25 ohm; The electric current that flows through is 1A, is 4.75V (5-0.25*1=4.75) through the voltage after first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 dividing potential drops then.Because it is said above the basis; When being lower than 4.75V through the voltage after first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 dividing potential drops; The first triode Q1 is a closed condition; The voltage output that it has turn-offed circuit makes the utility model current foldback circuit be in the overcurrent protection state.Therefore; If regulate the parallelly connected resistance of first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4; Its parallelly connected resistance is diminished; The electric current that then need flow through first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 is during greater than 1A, just can be lower than 4.75V through the voltage after first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 dividing potential drops, and the voltage between the base stage of the 3rd triode Q3 and its emitter just can be less than 0.7V; The first triode Q1 also can be in closed condition, thus the just voltage output of meeting breaking circuit.Therefore; The over-current protection point of the utility model current foldback circuit is along with the variation of the parallelly connected resistance of first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4 changes, and also promptly can adjust the over-current protection point of the utility model current foldback circuit through the parallelly connected resistance of adjusting first resistance R 1, second resistance R 2, the 3rd resistance R 3 and the 4th resistance R 4.
The utility model also provides a kind of player; This player comprises USB output interface and HDMI output interface; Output interface comprises current foldback circuit, and the circuit structure of its current foldback circuit repeats no more with reference to the described current foldback circuit of top embodiment here.
The beneficial effect of the utility model is: because the utility model adopts the combination of gadgets such as resistance, electric capacity and triode to replace the overcurrent protection chip of player output interface current foldback circuit in the prior art; Not only well solved the overcurrent protection problem of player output interface; Also reduced cost; And the utility model can also require the over-current protection point of its output interface is adjusted flexibly according to the difference output of player output interface, thereby has enlarged the range of application of this current foldback circuit.
The above is merely the preferred embodiment of the utility model; Be not thus the restriction the utility model claim; Every equivalent structure or equivalent flow process conversion that utilizes the utility model specification and accompanying drawing content to be done; Or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the utility model.
Claims (9)
1. current foldback circuit; Comprise voltage input end, voltage output end and main system circuit; It is characterized in that also comprise switching circuit, overcurrent adjustment circuit and feedback circuit, said switching circuit is used to control the voltage output state of said current foldback circuit; Said overcurrent adjustment circuit is used to adjust the over-current protection point of said current foldback circuit, and said feedback circuit is used to monitor the size of current of said voltage output end.
2. current foldback circuit according to claim 1; It is characterized in that; Said overcurrent adjustment circuit comprises first resistance, second resistance, the 3rd resistance, the 4th resistance, the 9th resistance and the tenth resistance, and after said first resistance, second resistance, the 3rd resistance and the 4th resistance were parallel with one another, the one of which common ends was connected with said switching circuit; Another common ends is connected with said voltage output end, is connected between said voltage output end and the ground after said the 9th resistance and the tenth resistance are connected each other.
3. current foldback circuit according to claim 2; It is characterized in that; Said switching circuit comprises the 5th resistance, the 6th resistance, the 7th resistance, the 8th resistance, first triode and second triode; Be connected in after said the 5th resistance and said the 6th resistance are parallel with one another between the collector electrode of base stage and said second triode of said first triode; The emitter of said first triode is connected with said voltage input end, and the collector electrode of said first triode is connected with said overcurrent adjustment circuit, and the base stage of said second triode is connected with the over-current signal detection pin of said main system circuit and an end of said the 7th resistance respectively through said the 8th resistance; The other end of said the 7th resistance is connected with said voltage input end, and the emitter of said second triode is connected with ground.
4. current foldback circuit according to claim 3; It is characterized in that; Said feedback circuit comprises the 11 resistance, the 12 resistance, electric capacity, the 3rd triode and the 4th triode; The base stage of said the 3rd triode is connected with said overcurrent adjustment circuit through said the 11 resistance; Be connected between said voltage input end and the ground after said the 12 resistance and said electric capacity are connected each other, the collector electrode of said the 3rd triode is connected between said the 12 resistance and the said electric capacity, and the emitter of said the 3rd triode is connected with ground; The base stage of said the 4th triode is connected with ground through said electric capacity, and the collector electrode of said the 4th triode detects pin with the over-current signal of said main system circuit and is connected.
5. current foldback circuit according to claim 4 is characterized in that, the collector electrode of first triode first resistance, second resistance, the 3rd resistance and the 4th resistance in said overcurrent adjustment circuit is connected with said voltage output end in the said switching circuit.
6. current foldback circuit according to claim 5 is characterized in that, the base stage of the 3rd triode is connected in the said overcurrent adjustment circuit between the 9th resistance and said the tenth resistance through said the 11 resistance in the said feedback circuit.
7. current foldback circuit according to claim 6 is characterized in that, said first triode is the PNP triode, and said second triode, the 3rd triode and the 4th triode are NPN utmost point pipe.
8. a player comprises output interface, it is characterized in that, said output interface comprises each described current foldback circuit among the claim 1-7.
9. player according to claim 8 is characterized in that, said output interface comprises USB output interface and HDMI output interface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120538954.XU CN202424107U (en) | 2011-12-19 | 2011-12-19 | Over-current protection circuit and player |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120538954.XU CN202424107U (en) | 2011-12-19 | 2011-12-19 | Over-current protection circuit and player |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN202424107U true CN202424107U (en) | 2012-09-05 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201120538954.XU Expired - Fee Related CN202424107U (en) | 2011-12-19 | 2011-12-19 | Over-current protection circuit and player |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN202424107U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102999009A (en) * | 2012-12-11 | 2013-03-27 | 深圳市麦格米特驱动技术有限公司 | Control circuit of machine tool |
| CN108879592A (en) * | 2018-07-27 | 2018-11-23 | Tcl通力电子（惠州）有限公司 | HDMI power overcurrent protection circuit and equipment |
-
2011
- 2011-12-19 CN CN201120538954.XU patent/CN202424107U/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102999009A (en) * | 2012-12-11 | 2013-03-27 | 深圳市麦格米特驱动技术有限公司 | Control circuit of machine tool |
| CN102999009B (en) * | 2012-12-11 | 2016-01-20 | 深圳市麦格米特驱动技术有限公司 | Control circuit of machine tool |
| CN108879592A (en) * | 2018-07-27 | 2018-11-23 | Tcl通力电子（惠州）有限公司 | HDMI power overcurrent protection circuit and equipment |
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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: 20120905 Termination date: 20201219 |
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| CF01 | Termination of patent right due to non-payment of annual fee |