CN103716970B - A kind of LED drive circuit - Google Patents
A kind of LED drive circuit Download PDFInfo
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- CN103716970B CN103716970B CN201410032477.8A CN201410032477A CN103716970B CN 103716970 B CN103716970 B CN 103716970B CN 201410032477 A CN201410032477 A CN 201410032477A CN 103716970 B CN103716970 B CN 103716970B
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Abstract
This application discloses a kind of LED drive circuit, it adds a control switching circuit on the basis of existing LED drive circuit, and current loop comprises two kinds of operation modes, the quick response mode that namely dynamic responding speed is larger and the less slow response mode of dynamic responding speed; By the control of control switching circuit, make output current amplitude less or when output voltage is lower than threshold value in dimmer voltage, current loop switches to and responds mode fast, thus under even if LLC main circuit is operated in discontinuous operation pattern, also can have enough fast dynamic conditioning speed, avoid the phenomenon that the output current ripple of LED drive circuit is larger; Otherwise in the rest of the cases, current loop switches to slow response mode, ensure that the stability of LED drive circuit under fully loaded transportation condition.
Description
Technical field
The application relates to technical field of circuit control, particularly relates to a kind of LED drive circuit.
Background technology
LED, i.e. light-emitting diode, as a kind of novel illumination device, because of advantages such as its light efficiency are high, the life-span is long, pollution-free, be used widely in lighting field.In order to make LED adapt to different application scenarios, LED drive circuit also has dimming function, namely according to different dim signals, exports the electric current of different amplitude to LED, thus regulates the luminosity of LED.
The following problem of existing LED drive circuit ubiquity: when light modulation proceeds to the current signal exporting small magnitude, or when the output voltage of LED drive circuit is lower, the ripple of this output current signal becomes large, its rear class load LED lamp brightness is caused constantly to change, namely there is stroboscopic phenomenon, and then certain infringement is caused to human eye.
Summary of the invention
In view of this, the application's object is to provide a kind of LED drive circuit, and to solve existing LED drive circuit when exporting the current signal of small magnitude, this current signal ripple becomes large problem.
For achieving the above object, the application provides following technical scheme:
A kind of LED drive circuit, comprising:
Main circuit, for exporting the current signal of certain amplitude to rear class LED;
Current loop, for the output current signal according to dimmer voltage and described main circuit, generates corresponding frequency change control signal;
Control chip, for carrying out variable frequency control according to described frequency change control signal to described main circuit, makes described main circuit export the current signal of respective magnitudes;
Described main circuit comprises the LLC main circuit of LLC topological form;
The operation mode of described current loop comprises: response mode and slow response mode fast; The dynamic responding speed of described current loop under described quick response mode is greater than the dynamic responding speed under described slow response mode;
Described LED drive circuit also comprises:
Control switching circuit, for the amplitude of the output voltage and dimmer voltage that judge described LLC main circuit whether all in corresponding preset range, if, then generate and export the first switching signal, described slow response mode is worked in control described current loop, otherwise generate the second switching signal, work in described quick response mode to control described current loop.
Preferably, described control switching circuit comprises:
First comparison circuit, for judging whether described output voltage is less than the first predetermined threshold value;
Second comparison circuit, for judging whether described dimmer voltage is less than the second predetermined threshold value; The output current amplitude of described LLC main circuit increases with the increase of described dimmer voltage;
First commutation circuit, for when the judged result of described first comparison circuit and the second comparison circuit is no, generate and export described first switching signal, have at least in the judged result of described first comparison circuit and the second comparison circuit one for being time, generate and export described second switching signal.
Preferably, described control switching circuit comprises:
3rd comparison circuit, for judging whether described output voltage is less than the 3rd predetermined threshold value;
4th comparison circuit, for judging whether described dimmer voltage is greater than the 4th predetermined threshold value; The output current amplitude of described LLC main circuit reduces with the increase of described dimmer voltage;
Second commutation circuit, for when the judged result of described 3rd comparison circuit and the 4th comparison circuit is no, generate and export described first switching signal, have at least in the judged result of described 3rd comparison circuit and the 4th comparison circuit one for being time, generate and export described second switching signal.
Preferably, described control switching circuit comprises: the second amplifier that the first amplifier that proportionality coefficient is K1, proportionality coefficient are K2, Signal averaging device and the 5th comparison circuit;
The input of described first amplifier accesses described output voltage, the input of described second amplifier accesses described dimmer voltage, the output of described first amplifier and the second amplifier is connected to the input of described Signal averaging device respectively, the output of described Signal averaging device is connected to the first input end of described 5th comparison circuit, second input access the 5th predetermined threshold value of described 5th comparison circuit, the output of described 5th comparison circuit is connected to described current loop.
Preferably, work as K1>0, K2>0, when the output current amplitude of described LLC main circuit increases with the increase of described dimmer voltage, if when described 5th comparison circuit judges that the signal of described first input end is less than the signal of described second input, the output of described 5th comparison circuit exports described second switching signal, otherwise the output of described 5th comparison circuit exports described first switching signal;
Or, work as K1>0, K2 < 0, when the output current amplitude of described LLC main circuit reduces with the increase of described dimmer voltage, if when described 5th comparison circuit judges that the signal of described first input end is less than the signal of described second input, the output of described 5th comparison circuit exports described second switching signal, otherwise the output of described 5th comparison circuit exports described first switching signal;
Or, as K1 < 0, K2>0, when the output current amplitude of described LLC main circuit reduces with the increase of described dimmer voltage, if when described 5th comparison circuit judges that the signal of described first input end is greater than the signal of described second input, the output of described 5th comparison circuit exports described second switching signal, otherwise the output of described 5th comparison circuit exports described first switching signal.
Preferably, described current loop comprises principal current loop, secondary ring and diverter switch;
Described secondary ring and diverter switch are connected in series, and the two series circuit formed is in parallel with described principal current loop.
Preferably, described diverter switch comprises the first diverter switch, for: disconnect when receiving described first switching signal, closed when receiving described second switching signal.
Preferably, described diverter switch comprises the second diverter switch, for: closed when receiving described first switching signal, disconnect when receiving described second switching signal.
Preferably, described diverter switch comprises any one in metal-oxide-semiconductor, triode and IGBT.
Preferably, described LLC main circuit is isolated form main circuit; Described LED drive circuit also comprises: be arranged at the isolated component between described current loop and control chip.
Preferably, described isolated component comprises optic coupling element.
Preferably, the excursion of described dimmer voltage is 0 ~ 10V.
As can be seen from above-mentioned technical scheme, the LED drive circuit that the application provides, add a control switching circuit, and current loop comprises two kinds of operation modes, the quick response mode that namely dynamic responding speed is larger and the less slow response mode of dynamic responding speed; By the control of control switching circuit, make output current amplitude less or when output voltage is lower than threshold value in dimmer voltage, current loop switches to and responds mode fast, thus under even if LLC main circuit is operated in discontinuous operation pattern, also can have enough fast dynamic conditioning speed, avoid the phenomenon that the output current ripple of LED drive circuit is larger; Otherwise in the rest of the cases, current loop switches to slow response mode, ensure that the stability of LED drive circuit under fully loaded transportation condition.Therefore, the embodiment of the present application solves the problem of prior art.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present application or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is only some embodiments of the application, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.
Fig. 1 is the circuit block diagram of existing LED drive circuit;
The circuit block diagram of the LED drive circuit that Fig. 2 provides for the embodiment of the present application one;
The circuit block diagram of the LED drive circuit that Fig. 3 provides for the embodiment of the present application two;
A kind of circuit diagram of control switching circuit in the LED drive circuit that Fig. 4 provides for the embodiment of the present application two;
The circuit block diagram of the LED drive circuit that Fig. 5 provides for the embodiment of the present application three;
A kind of circuit diagram of control switching circuit in the LED drive circuit that Fig. 6 provides for the embodiment of the present application three;
The circuit block diagram of the LED drive circuit that Fig. 7 provides for the embodiment of the present application four;
The circuit block diagram of the LED drive circuit that Fig. 8 provides for the embodiment of the present application five.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present application, be clearly and completely described the technical scheme in the embodiment of the present application, obviously, described embodiment is only some embodiments of the present application, instead of whole embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the application's protection.
The embodiment of the present application discloses a kind of LED drive circuit, and to solve existing LED drive circuit when exporting the current signal of small magnitude, this current signal ripple becomes large problem.
Applicant studies discovery, and existing is the LED drive circuit of main circuit with LLC topology, and when the amplitude of its output current signal is less, the reason of ripple increase is: when the amplitude of its output current signal is less, LLC main circuit is operated in discontinuous operation pattern.
Concrete, the LED drive circuit being main circuit with LLC topology as shown in Figure 1, comprises LLC main circuit 100, current loop 200 and control chip 300(i.e. control IC).Its operation principle is: the dim signal (being generally voltage signal Vs) that current loop 200 inputs according to outside and inner reference signal, and compare with the current signal Io that this LED drive circuit exports, and generate corresponding frequency change control signal according to comparative result; Control chip 300 carries out variable frequency control according to described frequency change control signal to LLC main circuit 100; LLC main circuit 100 i.e. topological form is the main circuit of LLC topology, under the control of control chip 300, the current signal (current signal that the current signal that LLC main circuit 100 exports i.e. this LED drive circuit exports) of respective magnitudes is exported, to control the brightness of LED D1 to rear class load LED lamp D1.
When the brightness demand of the LED that dim signal characterizes is less, the current signal amplitude that LLC main circuit 100 exports is less, the successive load (i.e. LED D1) of this LED drive circuit is underloading, under the control of control chip 300, the operating frequency of LLC main circuit is in a higher numerical value, for reducing circuit loss, LLC main circuit 100 enters discontinuous operation pattern, thus increases the ripple of output current signal.
For solving the problem, the embodiment of the present application one provides a kind of LED drive circuit, and as shown in Figure 2, it comprises LLC main circuit 100, current loop 200, control chip 300 and control switching circuit 400.
Wherein, current loop 200 comprises response mode and slow response mode two kinds of operation modes fast; The dynamic responding speed of described current loop under described quick response mode is greater than the dynamic responding speed under described slow response mode.
Control switching circuit 400, for judging that the amplitude of output voltage (i.e. load voltage) Vo and dimmer voltage Vs of LLC main circuit 100 is whether all in corresponding preset range, if, then generate and export the first switching signal, described slow response mode is worked in control current loop 200, otherwise generate the second switching signal, work in described quick response mode to control current loop 200.
The operation principle of above-mentioned LED drive circuit is:
1) when the amplitude of output voltage Vo and dimmer voltage Vs is all in corresponding preset range, the successive load of this LED drive circuit is heavy duty, and there is not the larger problem of output signal ripple, control switching circuit 400 generates and exports the first switching signal, under the control of this first switching signal, current loop 200 works in described slow response mode, and related circuit parameter is identical with the current loop of existing LED drive circuit, ensure that the stability of LED drive circuit under fully loaded transportation condition.
2) when the amplitude of output voltage Vo or dimmer voltage Vs (comprises Vo and Vs all not in corresponding preset range) not in corresponding preset range, control switching circuit 400 generates and exports the second switching signal, under the control of this second switching signal, current loop 200 works in described quick response mode; Under responding mode fast, the dynamic responding speed of current loop 200 is much larger than described slow response mode, even if under LLC main circuit 100 is operated in discontinuous operation pattern, also enough fast dynamic conditioning speed can be had, greatly reduce the output current ripple of LED drive circuit, avoid the stroboscopic phenomenon of successive load LED.
In above-described embodiment, by arranging corresponding circuit parameter, current loop 200 can be made to have different dynamic responding speed, namely there is different operation modes; Under slow response mode and fast response mode, the response speed occurrence of current loop 200 is also determined according to practical situations, to reach the best dimming effect under respective application occasion.
From foregoing circuit structure and the course of work, the LED drive circuit that the embodiment of the present application provides, add a control switching circuit, and current loop comprises two kinds of operation modes, the quick response mode that namely dynamic responding speed is larger and the less slow response mode of dynamic responding speed; By the control of control switching circuit, make output current signal amplitude less or when output voltage is lower than threshold value in dimmer voltage, current loop switches to and responds mode fast, thus under even if LLC main circuit is operated in discontinuous operation pattern, also can have enough fast dynamic conditioning speed, avoid the phenomenon that the output current ripple of LED drive circuit is larger; Otherwise in the rest of the cases, current loop switches to slow response mode, ensure that the stability of LED drive circuit under fully loaded transportation condition.Therefore, the embodiment of the present application solves the problem of prior art.
In practical application, the concrete structure of control switching circuit has multiple, and the embodiment of the present application provides 3 kinds of concrete structures as shown in Fig. 3, Fig. 5 and Fig. 7, sets forth respectively below to it.
As shown in Figure 3, the LED drive circuit that the embodiment of the present application two provides, is characterized in that, described control switching circuit comprises: comprise LLC main circuit 100, current loop 200, control chip 300 and control switching circuit 400; Wherein, the output current amplitude of LLC main circuit 100 increases with the increase of described dimmer voltage Vs; The operation mode of current loop 200 comprises response mode and slow response mode fast; Control switching circuit 400 comprises the first comparison circuit 410, second comparison circuit 420 and the first commutation circuit 430.
Concrete, the first comparison circuit 410, for judging whether the output voltage Vo of LLC main circuit 100 is less than the first predetermined threshold value V
ref1;
Second comparison circuit 420, for judging whether described dimmer voltage Vs is less than the second predetermined threshold value V
ref2;
First commutation circuit 430, for when the judged result of described first comparison circuit and the second comparison circuit is no, generate and export described first switching signal, have at least in the judged result of described first comparison circuit and the second comparison circuit one for being time, generate and export described second switching signal.
More specifically, as shown in Figure 4, the first comparison circuit 410 comprises comparator B1, and the normal phase input end access output voltage Vo of B1, inverting input accesses the first predetermined threshold value V
ref1; Second comparison circuit 420 comprises comparator B2, and the normal phase input end access output voltage Vs of B2, inverting input accesses the second predetermined threshold value V
ref2; First commutation circuit 430 comprises and door A1.
When the judged result of the first comparison circuit 410 and the second comparison circuit 420 be no, namely B1 and B2 all exports high level time, A1 exports high level, as the first switching signal, controls current loop 200 and works in slow response mode.Otherwise, in the judged result of the first comparison circuit 410 and the second comparison circuit 420, have at least one to be yes, i.e. B1 output low level, or B2 output low level, or during the equal output low level of B1 and B2, A1 output low level, as the second switching signal, control current loop 200 works in and responds mode fast.
As shown in Figure 5, the LED drive circuit that the embodiment of the present application three provides, comprises LLC main circuit 100, current loop 200, control chip 300 and control switching circuit 400; Wherein, the output current amplitude of LLC main circuit 100 reduces with the increase of described dimmer voltage Vs; The operation mode of current loop 200 comprises response mode and slow response mode fast; Control switching circuit 400 comprises the 3rd comparison circuit 440, the 4th comparison circuit 450 and the second commutation circuit 460.
Concrete, the 3rd comparison circuit 440, for judging whether the output voltage Vo of LLC main circuit 100 is less than the 3rd predetermined threshold value V
ref3;
4th comparison circuit 450, for judging whether described dimmer voltage Vs is greater than the 4th predetermined threshold value V
ref4;
Second commutation circuit 460, for when the judged result of the 3rd comparison circuit 440 and the 4th comparison circuit 450 is no, generate and export described first switching signal, have at least in the judged result of the 3rd comparison circuit 440 and the 4th comparison circuit 450 one for being time, generate and export described second switching signal.
More specifically, as shown in Figure 6, the 3rd comparison circuit 440 comprises comparator B3, the normal phase input end access output voltage Vo of B3, inverting input access the 3rd predetermined threshold value V
ref3; 4th comparison circuit 450 comprises comparator B4, the inverting input access output voltage Vs of B4, normal phase input end access the 4th predetermined threshold value V
ref4; Second commutation circuit 460 comprises and door A2.
When the judged result of the 3rd comparison circuit 440 and the 4th comparison circuit 450 be no, namely B3 and B4 all exports high level time, A2 exports high level, as the first switching signal, controls current loop 200 and works in slow response mode.Otherwise, in the judged result of the 3rd comparison circuit 440 and the 4th comparison circuit 450, have at least one to be yes, i.e. B3 output low level, or B4 output low level, or during the equal output low level of B3 and B4, A2 output low level, as the second switching signal, control current loop 200 works in and responds mode fast.
As shown in Figure 7, the LED drive circuit that the embodiment of the present application four provides, is characterized in that, described control switching circuit comprises: comprise LLC main circuit 100, current loop 200, control chip 300 and control switching circuit 400; Wherein, the output current amplitude of LLC main circuit 100 with the increase of described dimmer voltage Vs monotone variation; The operation mode of current loop 200 comprises response mode and slow response mode fast; Control switching circuit 400 comprises the first amplifier 471, second amplifier 472, Signal averaging device 480 and the 5th comparison circuit 490.
Concrete, the proportionality coefficient of the first amplifier 471 is K1, and its input accesses described output voltage Vo, and namely the first amplifier 471 produces the scaling signal K1*Vo of output voltage.Accordingly, the proportionality coefficient of the second amplifier 472 is K2, and its input accesses described dimmer voltage Vs, and namely the second amplifier 472 produces the scaling signal K2*Vs of dimmer voltage Vs.
Signal averaging device 480, for the output signal of the first amplifier 471 and the second amplifier 472 being superposed, namely produces superposed signal K1*Vo+K2*Vs; 5th comparison circuit 490 is by this superposed signal K1*Vo+K2*Vs and the 5th predetermined threshold value V
ref5compare, to produce corresponding switch-over control signal.
According to the output current amplitude of LLC main circuit 100 with the Changing Pattern of described dimmer voltage, control switching circuit 400 is arranged, to meet demand for control:
1) when the output current amplitude of LLC main circuit 100 increases with the increase of described dimmer voltage, setting K1 > 0, K2 > 0; Based on this, when the 5th comparison circuit 490 judges that signal that its first input end receives is less than the signal that its second input receives, the output of the 5th comparison circuit 490 exports the second switching signal, otherwise the output of the 5th comparison circuit 490 exports the first switching signal.
More specifically, if be described first switching signal with high level signal, low level signal is described second switching signal, then can using the first input end of the 5th comparison circuit 490 as normal phase input end, and the second input is as negative-phase input.
Based on above-mentioned setting, turn brightness down when LED number is selected, namely output voltage Vo is constant, dimmer voltage Vs reduce and too small (the output current amplitude of the LLC main circuit 100 that Vs is corresponding is too small) time, corresponding superposed signal is also less, thus by rationally arranging the 5th predetermined threshold value V
ref5size, the 5th comparison circuit 490 can be made to export the second switching signal, and then current loop 200 is worked in respond mode fast.
2) when the output current amplitude of LLC main circuit 100 reduces with the increase of described dimmer voltage, K1 > 0, K2 < 0 can be set; Based on this, when the 5th comparison circuit 490 judges that signal that its first input end receives is less than the signal that its second input receives, the output of the 5th comparison circuit 490 exports the second switching signal, otherwise the output of the 5th comparison circuit 490 exports the first switching signal.
Based on above-mentioned setting, turn brightness down when LED number is selected, namely output voltage Vo is constant, dimmer voltage Vs increase and excessive (the output current amplitude of the LLC main circuit 100 that Vs is corresponding is too small) time, corresponding superposed signal will be less, thus by rationally arranging the 5th predetermined threshold value V
ref5size, the 5th comparison circuit 490 can be made to export the second switching signal, and then current loop 200 is worked in respond mode fast.
3) when the output current amplitude of LLC main circuit 100 reduces with the increase of described dimmer voltage, K1 < 0, K2 > 0 can also be set; Based on this, when the 5th comparison circuit 490 judges that signal that its first input end receives is greater than the signal that its second input receives, the output of the 5th comparison circuit 490 exports the second switching signal, otherwise the output of the 5th comparison circuit 490 exports the first switching signal.
Based on above-mentioned setting, turn brightness down when LED number is selected, namely output voltage Vo is constant, dimmer voltage Vs increase and excessive (the output current amplitude of the LLC main circuit 100 that Vs is corresponding is too small) time, corresponding superposed signal will be comparatively large, thus by rationally arranging the 5th predetermined threshold value V
ref5size, the 5th comparison circuit 490 can be made to export the second switching signal, and then current loop 200 is worked in respond mode fast.
It should be noted that, above-mentioned 1), 2) and 3) three kinds of situations are for fixing K1, K2 and the 5th predetermined threshold value V
ref5, when LED number reduces, namely when output voltage Vo reduces, control switching circuit 400 exports the second switching signal and increases to the LED luminance corresponding to the moment controlling current loop 200 and work in fast response mode.
In the embodiment of the present application, the connection in series-parallel relation of current loop internal circuit element is changed by the first switching signal and the second switching signal, change its circuit parameter, thus change its dynamic responding speed, make it work in slow response mode or respond mode fast.Based on above-mentioned principle, the LED drive circuit that the embodiment of the present application five provides, as shown in Figure 8, it comprises LLC main circuit 100, current loop 200, control chip 300 and control switching circuit 400; Wherein, current loop 200 comprises principal current loop 210, secondary ring 220 and diverter switch 230; Secondary ring 220 and diverter switch 230 are connected in series, and the two series circuit formed is in parallel with principal current loop 210.
Concrete, principal current loop 210 can work independently, and the operation mode of corresponding current loop 200 is slow response mode; When principal current loop 210 and secondary ring 220 co-operation in parallel, the operation mode of corresponding current loop 200 is for respond mode fast.Accordingly, diverter switch 230 adopts the first diverter switch, for: disconnecting when receiving described first switching signal, making that principal current loop 210 works alone, current loop 200 is in as slow response mode; Closed when receiving described second switching signal, make principal current loop 210 and secondary ring 220 co-operation in parallel, current loop 200 be in and respond mode fast.
In addition, also can be designed to: principal current loop 210 works alone, the operation mode of corresponding current loop 200 is for respond mode fast; When principal current loop 210 and secondary ring 220 co-operation in parallel, the operation mode of corresponding current loop 200 is slow response mode.Now, diverter switch 230 adopts the second diverter switch, for: closed when receiving described first switching signal, make principal current loop 210 and secondary ring 220 co-operation in parallel, current loop 200 be in as slow response mode; Disconnecting when receiving described second switching signal, making that principal current loop 210 works alone, current loop 200 is in and responds mode fast.
Diverter switch described in the embodiment of the present application four, is preferably electronic switch, as metal-oxide-semiconductor, triode and IGBT etc.
In addition, in the embodiment of the present application, LLC main circuit is preferably isolated form main circuit; Accordingly, described LED drive circuit also comprises: be arranged at the isolated component between described current loop and control chip.
Concrete, described isolated component comprises optic coupling element.
In the embodiment of the present application, the dimming mode of LED drive circuit is preferably linearity light adjusting, and the adjustable extent of dimmer voltage Vs is preferably 0 ~ 10V.
One of ordinary skill in the art will appreciate that all or part of flow process realized in above-described embodiment method, that the hardware that can carry out instruction relevant by computer program has come, described program can be stored in a computer read/write memory medium, described program, when performing, can comprise the flow process of the embodiment as above-mentioned each side method.Wherein, described storage medium can be magnetic disc, CD, read-only store-memory body (Read-Only Memory, ROM) or random store-memory body (Random Access Memory, RAM) etc.
To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the application.To be apparent for those skilled in the art to the multiple amendment of these embodiments, General Principle as defined herein when not departing from the spirit or scope of the application, can realize in other embodiments.Therefore, the application can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.
Claims (11)
1. a LED drive circuit, comprising:
Main circuit, for exporting the current signal of certain amplitude to rear class LED;
Current loop, for the output current signal according to dimmer voltage and described main circuit, generate corresponding frequency change control signal, described current loop comprises principal current loop, secondary ring and diverter switch; Described secondary ring and diverter switch are connected in series, and the two series circuit formed is in parallel with described principal current loop;
Control chip, for carrying out variable frequency control according to described frequency change control signal to described main circuit, makes described main circuit export the current signal of respective magnitudes;
It is characterized in that, described main circuit comprises the LLC main circuit of LLC topological form;
The operation mode of described current loop comprises: response mode and slow response mode fast; The dynamic responding speed of described current loop under described quick response mode is greater than the dynamic responding speed under described slow response mode;
Described LED drive circuit also comprises:
Control switching circuit, for the amplitude of the output voltage and dimmer voltage that judge described LLC main circuit whether all in corresponding preset range, if, then generate and export the first switching signal to described diverter switch, described slow response mode is worked in control described current loop, otherwise generate the second switching signal to described diverter switch, work in described quick response mode to control described current loop.
2. LED drive circuit according to claim 1, is characterized in that, described control switching circuit comprises:
First comparison circuit, for judging whether described output voltage is less than the first predetermined threshold value;
Second comparison circuit, for judging whether described dimmer voltage is less than the second predetermined threshold value; The output current amplitude of described LLC main circuit increases with the increase of described dimmer voltage;
First commutation circuit, for when the judged result of described first comparison circuit and the second comparison circuit is no, generate and export described first switching signal, have at least in the judged result of described first comparison circuit and the second comparison circuit one for being time, generate and export described second switching signal.
3. LED drive circuit according to claim 1, is characterized in that, described control switching circuit comprises:
3rd comparison circuit, for judging whether described output voltage is less than the 3rd predetermined threshold value;
4th comparison circuit, for judging whether described dimmer voltage is greater than the 4th predetermined threshold value; The output current amplitude of described LLC main circuit reduces with the increase of described dimmer voltage;
Second commutation circuit, for when the judged result of described 3rd comparison circuit and the 4th comparison circuit is no, generate and export described first switching signal, have at least in the judged result of described 3rd comparison circuit and the 4th comparison circuit one for being time, generate and export described second switching signal.
4. LED drive circuit according to claim 1, is characterized in that, described control switching circuit comprises: the second amplifier that the first amplifier that proportionality coefficient is K1, proportionality coefficient are K2, Signal averaging device and the 5th comparison circuit;
The input of described first amplifier accesses described output voltage, the input of described second amplifier accesses described dimmer voltage, the output of described first amplifier and the second amplifier is connected to the input of described Signal averaging device respectively, the output of described Signal averaging device is connected to the first input end of described 5th comparison circuit, second input access the 5th predetermined threshold value of described 5th comparison circuit, the output of described 5th comparison circuit is connected to described current loop.
5. LED drive circuit according to claim 4, it is characterized in that, work as K1>0, K2>0, when the output current amplitude of described LLC main circuit increases with the increase of described dimmer voltage, if when described 5th comparison circuit judges that the signal of described first input end is less than the signal of described second input, the output of described 5th comparison circuit exports described second switching signal, otherwise the output of described 5th comparison circuit exports described first switching signal;
Or, work as K1>0, K2 < 0, when the output current amplitude of described LLC main circuit reduces with the increase of described dimmer voltage, if when described 5th comparison circuit judges that the signal of described first input end is less than the signal of described second input, the output of described 5th comparison circuit exports described second switching signal, otherwise the output of described 5th comparison circuit exports described first switching signal;
Or, as K1 < 0, K2>0, when the output current amplitude of described LLC main circuit reduces with the increase of described dimmer voltage, if when described 5th comparison circuit judges that the signal of described first input end is greater than the signal of described second input, the output of described 5th comparison circuit exports described second switching signal, otherwise the output of described 5th comparison circuit exports described first switching signal.
6. the LED drive circuit according to any one of claim 1 to 5, is characterized in that, described diverter switch comprises the first diverter switch, for: disconnect when receiving described first switching signal, closed when receiving described second switching signal.
7. the LED drive circuit according to any one of claim 1 to 5, is characterized in that, described diverter switch comprises the second diverter switch, for: closed when receiving described first switching signal, disconnect when receiving described second switching signal.
8. the LED drive circuit according to any one of claim 1 to 5, is characterized in that, described diverter switch comprises any one in metal-oxide-semiconductor, triode and IGBT.
9. the LED drive circuit according to any one of Claims 1 to 5, is characterized in that, described LLC main circuit is isolated form main circuit; Described LED drive circuit also comprises: be arranged at the isolated component between described current loop and control chip.
10. LED drive circuit according to claim 9, is characterized in that, described isolated component comprises optic coupling element.
11. LED drive circuits according to any one of Claims 1 to 5, it is characterized in that, the excursion of described dimmer voltage is 0 ~ 10V.
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| CN201410032477.8A CN103716970B (en) | 2014-01-23 | 2014-01-23 | A kind of LED drive circuit |
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| CN201410032477.8A CN103716970B (en) | 2014-01-23 | 2014-01-23 | A kind of LED drive circuit |
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|---|---|---|---|---|
| CN105188197B (en) * | 2015-08-13 | 2018-05-01 | 英飞特电子（杭州）股份有限公司 | A kind of LED drive circuit |
| CN116189606A (en) * | 2022-12-22 | 2023-05-30 | 深圳麦格米特电气股份有限公司 | Driving circuit, display device and control method of driving circuit |
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| EP2252131A1 (en) * | 2009-05-07 | 2010-11-17 | Linear Technology Corporation | Method and system for high efficiency, fast transient multi-channel led driver |
| CN102647823A (en) * | 2011-02-22 | 2012-08-22 | 英飞特电子（杭州）有限公司 | Constant current driving circuit for LED (Light Emitting Diode) lamp |
| CN103025009A (en) * | 2012-11-29 | 2013-04-03 | 余姚亿威电子科技有限公司 | Light-emitting diode (LED) driving control circuit |
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| EP2252131A1 (en) * | 2009-05-07 | 2010-11-17 | Linear Technology Corporation | Method and system for high efficiency, fast transient multi-channel led driver |
| CN102647823A (en) * | 2011-02-22 | 2012-08-22 | 英飞特电子（杭州）有限公司 | Constant current driving circuit for LED (Light Emitting Diode) lamp |
| CN103025009A (en) * | 2012-11-29 | 2013-04-03 | 余姚亿威电子科技有限公司 | Light-emitting diode (LED) driving control circuit |
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| CN103716970A (en) | 2014-04-09 |
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Effective date of registration: 20161018 Address after: 311500, No. 88 South Road, Tonglu Economic Development Zone, Tonglu County, Hangzhou, Zhejiang Patentee after: ZHEJIANG YINGFEITE OPTOELECTRONICS CO., LTD. Address before: Hangzhou City, Binjiang District province six and 310053 Zhejiang Road No. 368 building the North Sea base 3 Patentee before: LED One (Hangzhou) Co.,Ltd. |