CN202111450U

CN202111450U - Overcurrent protection circuit and television

Info

Publication number: CN202111450U
Application number: CN2010205145752U
Authority: CN
Inventors: 迟洪波; 韩文涛
Original assignee: Qingdao Hisense Electronics Co Ltd
Current assignee: Qingdao Hisense Electronics Co Ltd
Priority date: 2010-09-02
Filing date: 2010-09-02
Publication date: 2012-01-11
Anticipated expiration: 2020-09-02

Abstract

The embodiment of the utility model provides an overcurrent protection circuit and a television and relates to the technical field of electronics. The technical problem of easy damage of an LED (Light Emitting Diode) light bar due to the overcurrent phenomenon due to that the traditional protection circuit in the television cannot send a driving signal before the damage due to the overcurrent phenomenon of the LED light bar is solved. The overcurrent protection circuit comprises a current induction module, a first input end, a second input end and a first output end, wherein the first input end, the second input end and the first output end are connected with the current induction module; and when current which passes through the first input end and the second input end surpasses a preset value, the current induction module outputs a first driving signal through the first output end. The television comprises a driving chip, a power consumption device, a booster circuit and the overcurrent protection circuit provided by the embodiment of the utility model. The overcurrent protection circuit is used for the overcurrent protection of the power consumption device in a circuit.

Description

Circuit overcurrent protection and television set

Technical field

The utility model relates to electronic technology field, the television set that is specifically related to a kind of circuit overcurrent protection and is provided with this circuit overcurrent protection.

Background technology

Along with the develop rapidly of electronic technology and television technologies, television set has become one of household electrical appliance the most common in the daily life.

Usually be provided with multiple power consumption device in the television set; For example: be provided with LED (Light Emitting Diode in the liquid crystal display screen of existing liquid crystal TV set usually; Light-emitting diode) lamp bar can provide backlight when LED lamp bar is luminous for the liquid crystal panel of liquid crystal display screen.

As shown in Figure 1, existing television set comprises power management chip 6, chip for driving 3, power supply 4, booster circuit 5, LED lamp bar 9 and protective circuit, and protective circuit comprises overpower protection circuit 7 and excess voltage protection 8, wherein:

The needed electric energy of LED lamp bar 9 work is boosted to importing LED lamp bar 9 by the electric energy output end of booster circuit 5 after the rated operational voltage of LED lamp bar 9 through booster circuit 5 by power supply 4 outputs again;

Power management chip 6 is used to control power supply 4 and whether exports electric energy;

Whether chip for driving 3 is used to control booster circuit 5 and the electric energy of power supply 4 outputs is boosted, and the input of the electric energy after will boosting LED lamp bar 9;

Excess voltage protection 8 links to each other with chip for driving 3; Whether the voltage that excess voltage protection 8 is used to detect the electric energy output end input LED lamp bar 9 of booster circuit 5 surpasses predetermined value; When the voltage of the electric energy output end of booster circuit 5 surpasses predetermined value; Excess voltage protection 8 can be exported first drive signal, and with first drive signal input chip for driving 3;

When 8 pairs of chip for driving of excess voltage protection, 3 inputs, first drive signal; Chip for driving 3 gets into lock-out state, and when chip for driving 3 got into lock-out state, the electric energy output end of booster circuit 5 can stop to export electric energy; Chip for driving 3 gets into after the lock-out state; After needs operation manual work powered on to chip for driving 3 again, chip for driving 3 just can withdraw from lock-out state, starts once more;

Overpower protection circuit 7 links to each other with power management chip 6; Whether the power that overpower protection circuit 7 is used to detect LED lamp bar 9 (for example: rated power) surpasses predetermined value; When the power of LED lamp bar 9 surpasses predetermined value; Overpower protection circuit 7 can output second drive signal, and with the voltage of second drive signal input power management chip, 6, the second drive signals usually above first drive signal;

When having served as 7 pairs of power management chips of power protecting circuit, 6 inputs, second drive signal; Power management chip 6 gets into frequency hopping state (the frequency hopping state is restarted once after being meant one section preset time of street automatically), and when power management chip 6 got into the frequency hopping state, power supply 4 can stop to export electric energy; When not having the input of second drive signal; Power management chip 6 withdraws from the frequency hopping state, and when power management chip 6 withdrawed from the frequency hopping state, power supply 4 can be exported electric energy again.

In the process that realizes the utility model, the inventor finds to exist at least in the prior art following problem:

Protective circuit in the existing television set; Though can realize overpower protection or overvoltage protection to a certain extent to LED lamp bar 9 as shown in Figure 1; But in production, assembling and the use of LED lamp bar 9; Overpower or superpotential problem not only possibly appear in LED lamp bar 9, and overcurrent over the ground or short circuit very easily occur and cause LED lamp bar 9 that the situation of overcurrent takes place, when overcurrent or short-circuit conditions occurring over the ground; Big electric current (this electric current is called as overcurrent) can occur and LED lamp bar 9 burnt, cause LED lamp bar 9 to damage through LED lamp bar 9;

But; When big electric current passes through LED lamp bar 9; Protective circuit in the existing television set is that excess voltage protection 8 and circuit overcurrent protection do not have the function of sending drive signal in LED lamp bar 9 generation overcurrent phenomenons and before damaging; So LED lamp bar 9 is prone to damage because of the overcurrent phenomenon, when serious, the fail safe that overcurrent over the ground that LED lamp bar 9 takes place or short circuit phenomenon also can influence whole television set.

The utility model content

The utility model embodiment provides a kind of circuit overcurrent protection on the one hand; A kind of television set that is provided with this circuit overcurrent protection also is provided on the other hand; Solve protective circuit in the existing television set and sent drive signal before can't damaging in LED lamp bar generation overcurrent phenomenon, and then caused LED lamp bar to be prone to the technical problem of damaging because of the overcurrent phenomenon.

For achieving the above object, the embodiment of the utility model adopts following technical scheme:

This circuit overcurrent protection comprises induction by current module and the first input end that links to each other with said induction by current module, second input and first output, wherein:

When the electric current that flows through said first input end and said second input surpassed first predetermined value, said induction by current module was exported first drive signal through said first output.

Compared with prior art, the technique scheme that provided of the utility model embodiment circuit overcurrent protection can produce following technique effect at least:

Because in the circuit overcurrent protection that the utility model embodiment is provided; When the electric current that flows through the first input end and second input surpasses first predetermined value; The induction by current module can be exported first drive signal through first output; This shows; If with first input end and second input be connected in the power consumption device (for example: the LED lamp bar in the television set) and the electric energy output end of supplying power for the power consumption device (for example: in the time of the electric energy output end of television set booster circuit); The induction by current module can be passed through the first input end and the second input collection, and then identification flows through the current value for the electric current of the electric energy output end of power consumption device power supply and power consumption device, thereby judges the phenomenon that whether has overcurrent on the power consumption device;

Simultaneously; Because the induction by current module also can be when the electric current that flows through the first input end and second input surpasses first predetermined value; Export first drive signal; Promptly can also the form of the state that whether has the overcurrent phenomenon on the power consumption device with drive signal be sent through first output; So in actual production, operating personnel can be redefined for the lowest high-current value that power consumption device operate as normal can bear with first predetermined value, like this; When overcurrent or short circuit take place over the ground and cause the phenomenon of overcurrent takes place in the power consumption device; The induction by current module can be in power consumption device generation overcurrent phenomenon such as LED lamp bar and before damaging, and the state of the power consumption device generation overcurrent phenomenon form with drive signal is sent through first output, so solved the technical problem that protective circuit in the existing television set is sent drive signal before can't damaging in LED lamp bar generation overcurrent phenomenon.

Further, said first input end and said second input link to each other with the electric energy output end of the said electric current of output along the direction of said current delivery respectively successively;

Said induction by current module comprises first resistance, second resistance and a PNP triode, wherein:

Said first resistance is connected between said first input end and said second input;

The emitter of a said PNP triode links to each other with said first input end; The base stage of a said PNP triode links to each other with said second input, and the collector electrode of a said PNP triode links to each other with said second resistance of said first output and ground connection respectively.

Further, said induction by current module also comprises first electric capacity and first diode, wherein:

The two poles of the earth of said first electric capacity link to each other with said first input end and said second input respectively;

The positive pole of said first diode links to each other with the collector electrode of a said PNP triode, said second resistance respectively, and the negative pole of said first diode links to each other with said first output.

Further, said induction by current module also comprises the 3rd resistance, and said the 3rd resistance is connected between the collector electrode and said first output of a said PNP triode.

Further, said induction by current module also comprises the 4th resistance and the 5th resistance, wherein:

Said the 4th resistance is connected between the negative pole of said electric energy output end and said first diode;

The negative pole of said first diode links to each other with said the 5th resistance and said first output of said the 4th resistance, ground connection respectively.

Further, this circuit overcurrent protection also comprises isolation boosting module and second output that links to each other with said isolation boosting module, wherein:

Said isolation boosting module links to each other with said first output; Said isolation boosting module is used for when receiving said first drive signal of said first output output, being higher than second drive signal of said first drive signal through the said second output output voltage values.

Further, said isolation boosting module comprises drawing on NPN triode, the optical coupler, first draws power supply and the 2nd PNP triode on the power supply, second, wherein:

The base stage of said NPN triode links to each other with said first output, the grounded emitter of said NPN triode, and the collector electrode of said NPN triode links to each other with the negative pole of photophore in the said optical coupler;

Draw power supply to link to each other on the positive pole and said first of photophore in the said optical coupler; In the said optical coupler positive pole of light-receiving device respectively with said second on draw the base stage of power supply and said the 2nd PNP triode to link to each other, the minus earth of the interior light-receiving device of said optical coupler;

Draw power supply to link to each other on the emitter of said the 2nd PNP triode and said second, the collector electrode of said the 2nd PNP triode links to each other with said second output.

Further, said isolation boosting module also comprises the 6th resistance, voltage stabilizing didoe and/or second diode of ground connection, wherein:

The collector electrode of said the 2nd PNP triode links to each other with said second output and said the 6th resistance respectively;

The positive pole of said voltage stabilizing didoe links to each other with the positive pole of light-receiving device in the said optical coupler, the negative pole of said voltage stabilizing didoe respectively with said second on draw the base stage of power supply, said the 2nd PNP triode to link to each other;

The positive pole of said second diode links to each other with the collector electrode of said the 2nd PNP triode, and the negative pole of said second diode links to each other with said second output, said the 6th resistance respectively.

Further, said isolation boosting module also comprises the 7th resistance, the 8th resistance and the 9th resistance, wherein:

Said the 7th resistance is connected between the emitter that draws power supply and said the 2nd PNP triode on said second;

Said the 8th resistance is connected between the base stage of the negative pole that draws power supply and said voltage stabilizing didoe on said second, said the 2nd PNP triode;

Said the 9th resistance is connected between the base stage of said the 2nd PNP triode and the negative pole of said voltage stabilizing didoe, said the 8th resistance;

The resistance of said the 9th resistance is greater than said the 7th resistance, and the resistance of said the 7th resistance is greater than said the 8th resistance.

This television set comprises the circuit overcurrent protection that chip for driving, booster circuit, power consumption device and above-mentioned the utility model embodiment are provided, wherein:

The said first input end of said circuit overcurrent protection and said second input are connected between the electric energy output end and said power consumption device of said booster circuit;

Said chip for driving links to each other with said first output and said booster circuit respectively;

When said first output was imported said first drive signal to said chip for driving, said chip for driving got into lock-out state.

Further, this television set also comprises isolation boosting module in the circuit overcurrent protection that power supply, power management chip, above-mentioned the utility model embodiment provided and second output that links to each other with said isolation boosting module, wherein:

Said first input end and said second input link to each other with the electric energy output end of said power supply respectively;

Said isolation boosting module links to each other with said first output; Said isolation boosting module is used for when receiving said first drive signal of said first output output, being higher than second drive signal of said first drive signal through the said second output output voltage values;

Said power management chip links to each other with said second output and said power supply respectively;

When said second output is imported said second drive signal to said power management chip; Said power management chip gets into the frequency hopping state; When no said second drive signal was imported said power management chip, said power management chip withdrawed from the frequency hopping state.

Compared with prior art, the technique scheme that provided of the utility model embodiment television set can produce following technique effect at least:

Because the television set that the utility model embodiment is provided comprises the circuit overcurrent protection that above-mentioned the utility model embodiment is provided; So the television set that the utility model embodiment is provided has identical technical characterictic with the circuit overcurrent protection that above-mentioned the utility model embodiment is provided; So not only can obtain identical technique effect, and can solve identical technical problem;

When the circuit overcurrent protection that above-mentioned the utility model embodiment is provided is applied to protect the power consumption device on the television set; For example: during LED lamp bar; If operating personnel are redefined for lowest high-current value that the LED lamp bar operate as normal that electric energy output end connected of booster circuit can bear (certainly with first predetermined value; First predetermined value also can be worth less than this); Between the electric energy output end and power consumption device that then first input end and said second input of circuit overcurrent protection is connected in booster circuit, simultaneously chip for driving is linked to each other with first output and the booster circuit of circuit overcurrent protection;

When the electric current that flows through booster circuit electric energy output end and power consumption device surpasses the lowest high-current value that LED lamp bar operate as normal can bear; First output can be imported first drive signal to chip for driving; At this moment; Chip for driving can get into lock-out state; And when chip for driving gets into lock-out state, receive the electric energy output end of the booster circuit of chip for driving control can stop to export electric energy, and then the electric current that can prevent to surpass the lowest high-current value that LED lamp bar operate as normal can bear causes damage to LED lamp bar; Send drive signal so solved protective circuit in the existing television set before can't damaging in LED lamp bar generation overcurrent phenomenon, and then cause LED lamp bar to be prone to the technical problem of damaging because of the overcurrent phenomenon.

Description of drawings

In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiment of the utility model, for those of ordinary skills; Under the prerequisite of not paying creative work property, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the protective circuit of LED lamp bar in the existing television set and is the sketch map of the annexation of the critical piece of the circuit of LED lamp bar power supply;

Fig. 2 is the annexation sketch map of each parts in the circuit overcurrent protection that a kind of execution mode provided of the utility model embodiment;

Fig. 3 is a kind of practical implementation circuit diagram of circuit overcurrent protection shown in Figure 2;

Fig. 4 is another practical implementation circuit diagram of circuit overcurrent protection shown in Figure 2;

Fig. 5 is the annexation sketch map of each parts in the circuit overcurrent protection that another execution mode provided of the utility model embodiment;

Fig. 6 is the practical implementation circuit diagram of circuit overcurrent protection shown in Figure 5;

Fig. 7 for the circuit overcurrent protection in the television set that a kind of execution mode provided of the utility model embodiment and with critical piece that circuit overcurrent protection links to each other between the sketch map of annexation;

Fig. 8 is the sketch map of each pin of chip for driving shown in Figure 7;

When Fig. 9 is applied to protect in the television set power consumption device for chip for driving shown in Figure 8, during power consumption device operate as normal and during power consumption device generation overcurrent, the wave form varies sketch map of voltage on the OUT pin of chip for driving and the OV pin;

Figure 10 for the circuit overcurrent protection in the television set that another execution mode provided of the utility model embodiment and with critical piece that circuit overcurrent protection links to each other between the sketch map of annexation;

Figure 11 is the sketch map of each pin of power management chip shown in Figure 10;

When Figure 12 is applied to protect in the television set power consumption device for power management chip shown in Figure 11, during power consumption device operate as normal and during power consumption device generation overcurrent, the wave form varies sketch map of voltage on the MUPPER_6 pin of power management chip and the FB pin;

Figure 13 for the circuit overcurrent protection in the television set that another execution mode provided of the utility model embodiment and with critical piece that circuit overcurrent protection links to each other between the sketch map of annexation.

Embodiment

To combine the accompanying drawing among the utility model embodiment below, the technical scheme among the utility model embodiment is carried out clear, intactly description, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, the every other embodiment that those of ordinary skills are obtained under the prerequisite of not paying creative work belongs to the scope that the utility model is protected.

It is a kind of simple in structure, with low cost that the utility model embodiment provides, and when being applied to protect LED lamp bar, circuit overcurrent protection and a kind of television set that is provided with this circuit overcurrent protection that can avoid LED lamp bar to damage because of the overcurrent phenomenon.

Circuit overcurrent protection as shown in Figure 2, that the utility model embodiment is provided comprises induction by current module 1 and the first input end IN1 that links to each other with said induction by current module 1, the second input IN2 and the first output OUT1, wherein:

When the electric current that flows through said first input end IN1 and the said second input IN2 surpassed first predetermined value, said induction by current module 1 was exported first drive signal through the said first output OUT1.

Because in the circuit overcurrent protection that the utility model embodiment is provided; When the electric current that flows through the first input end IN1 and the second input IN2 surpasses first predetermined value; Induction by current module 1 can be exported first drive signal through the first output OUT1; This shows; If with first input end IN1 and the second input IN2 be connected in power consumption device 10 as shown in Figure 7 (for example: the LED lamp bar in the television set) link to each other and for the electric energy output end AOUT as shown in Figure 3 of power consumption device 10 power supplies (for example: in the time of the electric energy output end AOUT of television set booster circuit); Induction by current module 1 can be gathered through the first input end IN1 and the second input IN2; And then identification flows through power consumption device 10 and is the current value of the electric current of the electric energy output end AOUT of power consumption device 10 power supply, thereby judges the phenomenon that whether has overcurrent on the power consumption device 10;

Simultaneously; Because induction by current module 1 also can be when the electric current that flows through the first input end IN1 and the second input IN2 surpasses first predetermined value; Export first drive signal; Promptly can also the form of the state that whether has the overcurrent phenomenon on the power consumption device 10 as shown in Figure 7 with drive signal be sent through the first output OUT1; So in actual production, operating personnel can be redefined for the lowest high-current value that power consumption device 10 operate as normal can bear with first predetermined value, like this; When overcurrent or short circuit take place over the ground and cause the phenomenon of overcurrent takes place in power consumption device 10; The overcurrent phenomenons can take place and before damaging at power consumption devices such as LED lamp bar 10 in induction by current module 1, and the state that power consumption device 10 is taken place the overcurrent phenomenons sends through the first output OUT1 with the form of drive signal, so solved the technical problem that protective circuit in the existing television set is sent drive signal before can't damaging in LED lamp bar generation overcurrent phenomenon.

As shown in Figure 3, the first input end IN1 and the second input IN2 link to each other with the electric energy output end AOUT of output current along the direction of current delivery respectively successively in the present embodiment;

Induction by current module 1 as shown in Figure 2 comprises first resistance R 1 as shown in Figure 3, second resistance R 2 and a PNP triode V1, wherein:

First resistance R 1 is connected between the first input end IN1 and the second input IN2;

The emitter of the one PNP triode V1 links to each other with first input end IN1, and the base stage of a PNP triode V1 links to each other with the second input IN2, and the collector electrode of a PNP triode V1 links to each other with second resistance R 2 of the first output OUT1 and ground connection respectively.

When big electric current flows through electric energy output end AOUT and flow into power consumption device 10 as shown in Figure 7; Owing to flow through the electric current at the two ends of first resistance R 1 as shown in Figure 3; Can produce pressure drop; So the current potential on the first input end IN1 is higher than the current potential on the second input IN2, the voltage of a PNP triode V1 base stage is higher than the voltage of a PNP triode V1 emitter, a PNP triode V1 conducting; At this moment, the first input end IN1 that links to each other with the collector electrode of a PNP triode V1 just can send out first drive signal.The size of the magnitude of voltage of first drive signal can be adjusted according to the resistance of first resistance R 1 and the tube voltage drop of PNP triode V1PN knot in the present embodiment.Second resistance R 2 of ground connection is used for a PNP triode V1 is carried out ground protection, and then guarantees the reliability and security of a PNP triode V1.

In the actual production in the present embodiment any resistance both can be merely a resistance and also can and/or be formed in parallel for the series connection of a plurality of resistance.For example: first resistance R 1 is formed by connecting resistance R 11,

resistance R

12 and 13 3 resistance of resistance R in the present embodiment.

As a kind of improvement of present embodiment, induction by current module 1 as shown in Figure 2 also comprises first capacitor C 1 as shown in Figure 3, the first diode VD1, wherein:

The two poles of the earth of first capacitor C 1 link to each other with the first input end IN1 and the second input IN2 respectively;

The positive pole of the first diode VD1 links to each other with collector electrode, second resistance R 2 of a PNP triode V1 respectively, and the negative pole of the first diode VD1 links to each other with the first output OUT1.

First capacitor C 1 can play and prevent the transient current spike, causes the situation of a PNP triode V1 transient error conducting to take place, thereby has improved the reliability of the utility model circuit overcurrent protection.

The first diode VD1 has good unilateral conduction; The chip that the single input of direction that can guarantee first drive signal of first output OUT1 output receives first drive signal (for example: chip for driving 3 as shown in Figure 7); But also the electric current of the first diode VD1 that can avoid flowing through can not pour in down a chimney, and then can protect a PNP triode V1.

Induction by current module 1 as shown in Figure 2 comprises that also the 3rd resistance R 3, the three resistance R 3 as shown in Figure 3 are connected between the collector electrode and the first output OUT1 of a PNP triode V1 in the present embodiment.

The 3rd resistance R 3 and first resistance R 1 play the effect of dividing potential drop jointly; Carry out to avoid the magnitude of voltage of first drive signal of first output OUT1 output too big, and the chip that causes a PNP triode V1 and receive first drive signal (for example: chip for driving 3 as shown in Figure 7) be damaged.

The 3rd resistance R 3 and first resistance R 1 in like manner can be merely a resistance and also can and/or be formed in parallel for a plurality of resistance series connection, and the 3rd resistance R 3 is in series by resistance R 31 and 32 two resistance of resistance R in the present embodiment.

Induction by current module 1 as shown in Figure 2 also comprises the 4th resistance R 4 as shown in Figure 4 and the 5th resistance R 5 in the present embodiment, wherein:

The 4th resistance R 4 is connected between the negative pole of the electric energy output end AOUT and the first diode VD1;

The negative pole of the first diode VD1 links to each other with the 5th resistance R 5 and the first output OUT1 of the 4th resistance R 4, ground connection respectively.

With the 3rd resistance R 3 as shown in Figure 3 and first resistance R 1 in like manner; The 4th resistance R 4 as shown in Figure 4 and the 5th resistance R 5 play the effect of dividing potential drop jointly; Can be when the electric current that flows through electric energy output end AOUT surpass first predetermined value; Avoid the voltage of electric energy output end AOUT output too big; And the chip that causes linking to each other with the first output OUT1 (for example: chip for driving 3 as shown in Figure 7) be damaged, and then can further strengthen the reliability and security of the electronic equipment that this circuit overcurrent protection is set.

As shown in Figure 5, as another improvement of present embodiment, circuit overcurrent protection also comprises isolation boosting module 2 and the second output OUT2 that links to each other with isolation boosting module 2 in the present embodiment, wherein:

Isolation boosting module 2 links to each other with the first output OUT1, and isolation boosting module 2 is used for when receiving first drive signal of first output OUT1 output, being higher than second drive signal of first drive signal through the second output OUT2 output voltage values.

Because at present; The part have circuit protection function chip (for example: the voltage request of drive signal power management chip 6 shown in figure 10) be higher than by the chip of first drive (for example: chip for driving 3 shown in figure 10), so need boost to importing the chip with circuit protection function higher after the second higher drive signal of voltage again to first drive signal to the drive signal voltage request.

This shows; Magnitude of voltage can be more than the kind of the chip with circuit protection function that higher drive signal can drive; So isolation boosting module 2 has enlarged the scope of the chip with circuit protection function that the utility model circuit overcurrent protection can drive, and then the application scenario of also having improved the utility model circuit overcurrent protection.

Isolation boosting module 2 as shown in Figure 5 comprises drawing on NPN triode Q as shown in Figure 6, the optical coupler N, first and draws power supply VCC2 and the 2nd PNP triode V2 on the power supply VCC1, second in the present embodiment, wherein:

The base stage of NPN triode Q links to each other with the first output OUT1, the grounded emitter of NPN triode Q, and the collector electrode of NPN triode Q links to each other with the negative pole of photophore in the optical coupler N;

Draw power supply VCC1 to link to each other on the positive pole and first of photophore in the optical coupler N, in the optical coupler N positive pole of light-receiving device respectively with second on draw the base stage of power supply VCC2 and the 2nd PNP triode V2 to link to each other, the minus earth of the interior light-receiving device of optical coupler N;

Draw power supply VCC2 to link to each other on the emitter and second of the 2nd PNP triode V2, the collector electrode of the 2nd PNP triode V2 links to each other with the second output OUT2.

Because the base stage of NPN triode Q as shown in Figure 6 links to each other with the first output OUT1; When the base stage of NPN triode Q receives first drive signal of first output OUT1 output; The 2nd PNP triode V2 conducting; At this moment, the positive pole of photophore forms the closed-loop path with its negative pole and luminous in the optical coupler N, and drawing power supply VCC1 on first is that photophore is supplied power in the optical coupler N; Light-receiving device in the optical coupler N sense in the optical coupler N photophore luminous after, the positive pole and the negative pole conducting of the light-receiving device in the optical coupler N;

Simultaneously, because the negative pole of the light-receiving device in the optical coupler N is a ground connection, so; This moment, the base voltage of the 2nd PNP triode V2 reduced, and the 2nd PNP triode V2 conducting draws the electric energy of power supply VCC2 output to export through the 2nd PNP triode V2 and from the second output OUT2 on second; At this moment; The second output OUT2 exports second drive signal, and the magnitude of voltage of second drive signal depends on the tube voltage drop of the output voltage that draws power supply VCC2 on second and the 2nd PNP triode V2PN knot, because the tube voltage drop of the 2nd PNP triode V2PN knot is less usually; And the tube voltage drop difference of various the 2nd PNP triode V2PN knots and little; So, when needing higher second drive signal of magnitude of voltage, can change the magnitude of voltage of output voltage higher second on draw power supply VCC2; Otherwise, when needing lower second drive signal of magnitude of voltage, can change the magnitude of voltage of output voltage lower second on draw power supply VCC2.

Optical coupler N not only has the effect that photoelectricity is isolated, and has better anti-jamming capability, so can avoid the influence of first drive signal to second drive signal.

The employed above-mentioned components and parts of present embodiment are more common electronic devices and components, have advantage with low cost, that be convenient to connect, so help to reduce the cost of the utility model oversampling circuit protective circuit.

Isolation boosting module 2 as shown in Figure 5 also comprises the 6th resistance R 6, voltage stabilizing didoe VZ and/or the second diode VD2 of ground connection as shown in Figure 6 in the present embodiment, wherein:

The collector electrode of the 2nd PNP triode V2 links to each other with the second output OUT2 and the 6th resistance R 6 respectively;

The positive pole of voltage stabilizing didoe VZ links to each other with the positive pole of light-receiving device in the optical coupler N, the negative pole of voltage stabilizing didoe VZ respectively with second on draw the base stage of power supply VCC2, the 2nd PNP triode V2 to link to each other;

The positive pole of the second diode VD2 links to each other with the collector electrode of the 2nd PNP triode V2, and the negative pole of the second diode VD2 links to each other with the second output OUT2, the 6th resistance R 6 respectively.

The 6th resistance R 6 of ground connection can play the effect of ground protection, and the magnitude of voltage that can prevent second drive signal is too big and to the chip that links to each other with the second output OUT2 (for example: power management chip 6 shown in figure 10) cause damage.

When the positive pole of voltage stabilizing didoe VZ light-receiving device in optical coupler N and negative pole conducting; Can keep a lower stable voltage; Keep the 2nd PNP triode V2 and be in conducting state, and then guarantee output second drive signal that the second output OUT2 is reliable, stable.

With the first diode VD1 in like manner; The second diode VD2 has good unilateral conduction; The chip that the single input of direction that can guarantee second drive signal of second output OUT2 output receives second drive signal (for example: power management chip 6 shown in figure 10); Simultaneously, the electric current of the second diode VD2 that can also avoid flowing through pours in down a chimney, and then can protect the 2nd PNP triode V2.

Isolation boosting module 2 as shown in Figure 5 is preferably the 6th resistance R 6, voltage stabilizing didoe VZ and the second diode VD2 that comprises ground connection simultaneously in the present embodiment; Certainly, in the present embodiment isolation boosting module 2 also can only comprise the 6th resistance R 6, voltage stabilizing didoe VZ and the second diode VD2 one of them or wherein two.

Isolation boosting module 2 as shown in Figure 5 also comprises the 7th resistance R 7 as shown in Figure 6, the 8th resistance R 8 and the 9th resistance R 9 in the present embodiment, wherein:

The 7th resistance R 7 is connected between the emitter that draws power supply VCC2 and the 2nd PNP triode V2 on second;

The 8th resistance R 8 is connected between the base stage of the negative pole that draws power supply VCC2 and voltage stabilizing didoe VZ on second, the 2nd PNP triode V2;

The 9th resistance R 9 is connected between the base stage of the 2nd PNP triode V2 and the negative pole of voltage stabilizing didoe VZ, said the 8th resistance R 8;

The resistance of the 9th resistance R 9 greater than the resistance of the 7th resistance R 7, the seven resistance R 7 greater than the 8th resistance R 8.

The 7th resistance R 7, the 8th resistance R 8 and the 9th resistance R 9 can be shared the output voltage that draws power supply VCC2 on second jointly; The resistance of the 9th resistance R 9 is greater than the resistance of the 7th resistance R 7, the seven resistance R 7 during greater than the 8th resistance R 8, can guarantee that optical coupler N is not during conducting; The voltage of the 2nd PNP triode V2 emitter is less than the voltage of the 2nd PNP triode V2 base stage; Thereby be in cut-off state, and then can avoid the 2nd PNP triode V2 at coupler not during conducting, the 2nd PNP triode V2 conducting; When causing power consumption device 10 shown in figure 10 that the overcurrent phenomenon does not take place, output second drive signal of the second output OUT2 mistake.

Television set as shown in Figure 7, that the utility model embodiment is provided comprises the circuit overcurrent protection that chip for driving 3, booster circuit 5, power consumption device 10 and above-mentioned the utility model embodiment are provided, wherein:

The first input end IN1 of circuit overcurrent protection and the second input IN2 are connected between the electric energy output end AOUT and power consumption device 10 of booster circuit 5;

Chip for driving 3 links to each other with the first output OUT1 and booster circuit 5 respectively;

When the first output OUT1 imported first drive signal to chip for driving 3, chip for driving 3 got into lock-out states.

When the circuit overcurrent protection that above-mentioned the utility model embodiment is provided is applied to protect power consumption device as shown in Figure 7 on the television set (for example: LED lamp bar) 10 the time; If operating personnel are redefined for the lowest high-current value that the booster circuit 5 LED lamp bar operate as normal that electric energy output end AOUT connected as shown in Figure 3 can bear (certainly with first predetermined value; First predetermined value also can be worth less than this); Between the electric energy output end AOUT and power consumption device 10 that then the first input end IN1 and the second input IN2 of circuit overcurrent protection is connected to booster circuit 5, when simultaneously the first output OUT1 of chip for driving 3 and circuit overcurrent protection and booster circuit 5 being linked to each other; When the electric current that flows through booster circuit 5 electric energy output end AOUT and power consumption device 10 surpasses the lowest high-current value that LED lamp bar operate as normal can bear; The first output OUT1 can be to chip for driving 3 inputs first drive signal; At this moment; Chip for driving 3 can get into lock-out state; And when chip for driving 3 gets into lock-out states, receive the electric energy output end AOUT of the booster circuit 5 of chip for driving 3 controls can stop to export electric energy, and then the electric current that can prevent to surpass the lowest high-current value that LED lamp bar operate as normal can bear causes damage to LED lamp bar; Send drive signal so solved protective circuit in the existing television set before can't damaging in LED lamp bar generation overcurrent phenomenon, and then cause LED lamp bar to be prone to the technical problem of damaging because of the overcurrent phenomenon.

Chip for driving 3 as shown in Figure 7 is preferably AP3039 chip as shown in Figure 8 in the present embodiment.When chip for driving 3 is the AP3039 chip; The first output OUT1 of the circuit overcurrent protection that the utility model embodiment is provided links to each other with the OV pin on the AP3039 chip; The OUT pin of AP3039 chip links to each other with booster circuit 5; The AP3039 chip just can receive first drive signal through the OV pin; Through the OUT pin booster circuit 5 is transmitted control signal, and then whether control booster circuit 5 boost the electric energy of power supply 4 outputs, and the input of the electric energy after will boosting power consumption device (for example: LED lamp bar) 10;

As shown in Figure 9; When using the AP3039 chip as chip for driving 3 as shown in Figure 7; When receiving the power consumption device operate as normal of the circuit overcurrent protection protection that the utility model embodiment provided and during power consumption device generation overcurrent; Voltage waveform on the AP3039 chip on the OV pin is the voltage waveform of first drive signal that the first output OUT1 exported, and the voltage waveform on the OUT pin is the voltage waveform of the control signal of booster circuit 5 being sent through the OUT pin.

Shown in figure 10, the present embodiment television set also comprises isolation boosting module 2 that power management chip 6, power supply 4, above-mentioned the utility model embodiment circuit overcurrent protection are provided and the second output OUT2 that links to each other with isolation boosting module 2, wherein:

Power management chip 6 links to each other with the second output OUT2 and power supply 4 respectively;

When the second output OUT2 imported second drive signal to power management chip 6, power management chip 6 got into the frequency hopping states, and when not having second drive signal input power management chip 6, power management chip 6 withdraws from the frequency hopping state.

When the electric current that flows through booster circuit 5 electric energy output end AOUT surpasses the lowest high-current value that LED lamp bar operate as normal can bear; The second output OUT2 can be to power management chip 6 inputs second drive signal; At this moment; Power management chip 6 can get into the frequency hopping state; When power management chip 6 gets into the frequency hopping states, receive the power supply 4 of power management chip 6 controls can stop to export electric energy, and then the electric current that also can prevent to surpass the lowest high-current value that LED lamp bar operate as normal can bear cause damage to LED lamp bar; Send drive signal so also can solve protective circuit in the existing television set before can't damaging in LED lamp bar generation overcurrent phenomenon, cause LED lamp bar to be prone to the technical problem of damaging because of the overcurrent phenomenon.

The television set that present embodiment provided is preferably chip for driving 3 or the power management chip 6 that only comprises shown in figure 13 of only comprising as shown in Figure 7.At this moment, only need chip for driving 3 or power management chip 6 both one of them (for example: the purpose of overcurrent protection LED lamp bar) just can realize to power consumption device 10 in the television set.

Certainly; The present embodiment television set also can shown in figure 10ly comprise chip for driving 3 and power management chip 6 simultaneously; During concrete the use, can only use chip for driving 3 and power management chip 6 both one of them that power consumption device in the television set 10 is carried out overcurrent protection as required.At this moment; Can be when chip for driving 3 and power management chip 6 both one of them break down; Wherein another proceeds overcurrent protection to power consumption device 10 in the television set in use, thereby can further improve the reliability and security of the utility model circuit overcurrent protection.

Power management chip 6 shown in figure 10 is preferably NCP1396 chip shown in figure 11 in the present embodiment; When power management chip 6 is the NCP1396 chip; The second output OUT2 of the circuit overcurrent protection that the utility model embodiment is provided links to each other with the FB pin on the NCP1396 chip; MUPPER_6 pin on the NCP1396 chip links to each other with power supply 4; The NCP1396 chip receives second drive signal that the second output OUT2 exports through the FB pin, through the MUPPER_6 pin power supply 4 is transmitted control signal.

Shown in figure 12; When using the conduct of NCP1396 chip like Figure 10 or power management chip 6 shown in Figure 13; When receiving the power consumption device operate as normal of the circuit overcurrent protection protection that the utility model embodiment provided and during power consumption device generation overcurrent; Voltage waveform on the NCP1396 chip on the FB pin is the voltage waveform of second drive signal that the second output OUT2 exported, and the voltage waveform on the MUPPER_6 pin is the voltage waveform of the control signal of power supply 4 being sent through the MUPPER_6 pin.

When chip for driving 3 is used AP3039 chip as shown in Figure 8, when power management chip 6 used NCP1396 chip shown in figure 11, the voltage of first drive signal was to be preferably 1.25V more than the 1.0V, and the voltage of second drive signal is more than the 6.0V, to be preferably 6.5V.

Certainly, chip for driving 3 and power management chip 6 also can use outside disclosed AP3039 chip of above-mentioned the utility model embodiment and the NCP1396 chip other to have the circuit protection chip of lock function or frequency hopping function in the present embodiment.Simultaneously, the voltage of the voltage of first drive signal and second drive signal can be adjusted through the mode of components and parts model or parameter value in the change circuit overcurrent protection according to the type of employed circuit protection chip.

Drawing the output voltage of power supply VCC1 on first in the present embodiment is 3～7V, is preferably 5V, and drawing the output voltage of power supply VCC2 on second is 8～20V, is preferably 12V.

Facts have proved; When drawing on first the output voltage that draws power supply VCC2 on power supply VCC1 and second to select above-mentioned magnitude of voltage for use in the present embodiment; The present embodiment circuit overcurrent protection is when power consumption device overcurrent, and first drive signal of output and second drive signal all can effectively drive AP3039 chip or NCP1396 chip.

The above; Be merely the embodiment of the utility model; But the protection range of the utility model is not limited thereto; Any technical staff who is familiar with the present technique field is in the technical scope that the utility model discloses, and the variation that can expect easily or replacement all should be encompassed within the protection range of the utility model.Therefore, the protection range of the utility model should be as the criterion with the protection range of claim.

Claims

1. a circuit overcurrent protection is characterized in that, comprises induction by current module and the first input end that links to each other with said induction by current module, second input and first output, wherein:

2. circuit overcurrent protection according to claim 1 is characterized in that, said first input end and said second input link to each other with the electric energy output end of the said electric current of output along the direction of said current delivery respectively successively;

3. circuit overcurrent protection according to claim 2 is characterized in that, said induction by current module also comprises first electric capacity and first diode, wherein:

4. circuit overcurrent protection according to claim 3 is characterized in that, said induction by current module also comprises the 4th resistance and the 5th resistance, wherein:

5. circuit overcurrent protection according to claim 1 is characterized in that, this circuit overcurrent protection also comprises isolation boosting module and second output that links to each other with said isolation boosting module, wherein:

6. circuit overcurrent protection according to claim 5 is characterized in that, said isolation boosting module comprises drawing on NPN triode, the optical coupler, first draws power supply and the 2nd PNP triode on the power supply, second, wherein:

7. circuit overcurrent protection according to claim 6 is characterized in that, said isolation boosting module also comprises the 6th resistance, voltage stabilizing didoe and/or second diode of ground connection, wherein:

8. circuit overcurrent protection according to claim 7 is characterized in that, said isolation boosting module also comprises the 7th resistance, the 8th resistance and the 9th resistance, wherein:

9. a television set is characterized in that, comprises the arbitrary said circuit overcurrent protection of chip for driving, booster circuit, power consumption device and claim 1 to 8, wherein:

10. television set according to claim 9 is characterized in that, this television set also comprises power supply, power management chip, said isolation boosting module and second output that links to each other with said isolation boosting module, wherein: