CN102665344A - Dimming circuit - Google Patents
Dimming circuit Download PDFInfo
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- CN102665344A CN102665344A CN2012101405082A CN201210140508A CN102665344A CN 102665344 A CN102665344 A CN 102665344A CN 2012101405082 A CN2012101405082 A CN 2012101405082A CN 201210140508 A CN201210140508 A CN 201210140508A CN 102665344 A CN102665344 A CN 102665344A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
The embodiment of the invention provides a dimming circuit. The dimming circuit is characterized by comprising an LED (light emitting diode) actuator, a comparison circuit, a control circuit and a switching circuit, wherein the comparison circuit outputs a power-off signal on the condition that a dimming signal meets a first preset condition; the LED actuator executes the power-off operation after receiving the power-off signal; the control circuit controls a switching signal output by the switching circuit to be low level if detecting that the LED actuator is in the power-off state, so that the switching circuit can stop controlling a current loop in the LED actuator; when the dimming signal meets a second preset condition, the comparison circuit stops outputting the power-off signal, and the LED actuator is in the power-on state; when detecting that the LED actuator meets a third preset condition, the control circuit stops controlling the switching circuit so that the LED actuator is in a current output state; the switching circuit converts the dimming signal to a switching signal, and the LED actuator changes the size of output current according to the switching signal. By adopting the method, the delay problem in the startup process of the LED actuator can be avoided.
Description
Technical field
The present invention relates to circuit field, in particular, relate to a kind of light adjusting circuit.
Background technology
Along with the fast development of LED Lighting Industry, LED becomes the development trend of following illumination gradually.The outstanding advantage of LED is for regulating the brightness in LED lamp source, i.e. light modulation.
Light-dimming method commonly used is to control the output current of led driver through the height of dim signal level, thereby realize the brightness regulation to led light source.
In the process that realizes the invention, the inventor finds that there is following shortcoming at least in prior art:
When first voltage that extinguishes state from corresponding led light source when dim signal increases to corresponding led light source and is second voltage of minimum brightness state; Because led driver need open machine again; Make the led driver can not output current; When dim signal increased to the tertiary voltage that is higher than this second voltage, led driver could output current.Just the output current at led driver increases to the process of non-zero from zero, led driver can occur and open the problem that machine postpones.
Summary of the invention
In view of this, the invention provides a kind of light adjusting circuit, the output current owing to led driver increases to the process of non-zero from zero in the prior art to overcome, and led driver can occur and open the problem that machine postpones.
For realizing above-mentioned purpose, the present invention provides following technical scheme:
A kind of light adjusting circuit comprises: led driver, comparison circuit, control circuit and change-over circuit;
Satisfy under the first pre-conditioned situation said comparison circuit output off signal at dim signal;
Said led driver shuts down after receiving said off signal;
After said control circuit detected said led driver and is off-mode, the switching signal of controlling said change-over circuit output was a low level, so that said change-over circuit stops to control the electric current loop in the said led driver;
Satisfy under the second pre-conditioned situation at said dim signal; Said comparison circuit stops to export said off signal; Detecting said led driver at said control circuit does not satisfy under the 3rd pre-conditioned situation; The switching signal of controlling said change-over circuit output is a low level, makes said change-over circuit stop to control the electric current loop in the said led driver, said led driver is in opens the machine state;
Detect said led driver at said control circuit and satisfy under the 3rd pre-conditioned situation, stop to control said change-over circuit, make said led driver be in the output current state;
Said change-over circuit converts dim signal to switching signal, and said led driver changes the size of output current according to said switching signal.
Wherein, said change-over circuit specifically comprises:
Resistance R 1, resistance R b1, resistance R b2 and operational amplifier U2;
The inverting input of operational amplifier U2 links to each other with the end of resistance R b1 and the end of resistance R b2 respectively; Second predeterminated voltage acts on the in-phase input end of operational amplifier U2; The output of operational amplifier U2 links to each other with an end of resistance R 1 and the other end of resistance R b2 respectively; The other end of resistance R 1 links to each other with the feedback end of electric current loop in the said led driver, and said dim signal acts on the other end of resistance R b1.
Wherein, said comparison circuit specifically comprises:
Comparator U1 and diode D1;
Said dim signal acts on the in-phase input end of comparator U1; First predeterminated voltage acts on the inverting input of comparator U1; The output of comparator U1 links to each other with the negative pole of diode D1, and the positive pole of diode D1 links to each other with the output of electric current loop in the said led driver;
Voltage at said dim signal is not more than under the situation of said first predeterminated voltage; Comparator U1 output low level signal; Cause diode D1 conducting, the output level of electric current loop in the said led driver is dragged down, wherein; Said off signal is the low level signal of comparator U1 output, and said first pre-conditionedly is not more than said first predeterminated voltage for the voltage of said dim signal; Under the situation of voltage greater than said first predeterminated voltage of said dim signal, comparator U1 exports high level, causes diode D1 conducting to end, wherein, said second pre-conditioned be that the voltage of said dim signal is greater than said first predeterminated voltage.
Wherein, said control circuit specifically comprises:
Switch S C, negative circuit and current rectifying and wave filtering circuit;
The end of switch S C links to each other with the output of operational amplifier U2, the other end ground connection of switch S C, and the control end of said switch S C links to each other with the output of said negative circuit;
The input of said negative circuit links to each other with the output of said current rectifying and wave filtering circuit, and the input of said current rectifying and wave filtering circuit connects the two ends of Transformer Winding in the said led driver;
Be in when said led driver under the situation of off-mode, said Transformer Winding two ends are low level signal, after said negative circuit anti-phase, act on the control end of said switch S C, and it is closed to control said switch S C; Voltage when the two ends that detect said Transformer Winding is not less than under the situation of the 3rd predeterminated voltage; The input of said current rectifying and wave filtering circuit is a high level; After said negative circuit anti-phase, act on the control end of said switch S C; Control said switch S C and break off, wherein, the said the 3rd pre-conditioned voltage for the two ends that detect said Transformer Winding is not less than said the 3rd predeterminated voltage.
Wherein, said change-over circuit is specially:
Resistance R 3;
The output of said control circuit links to each other with first end of resistance R 3, and said dim signal acts on first end of resistance R 3, and second end of resistance R 3 links to each other with the feedback end of electric current loop in the said led driver.
Wherein, said comparison circuit specifically comprises:
Comparator U1 and diode D1;
Said dim signal acts on the inverting input of comparator U1; Said the 4th predeterminated voltage acts on the in-phase input end of comparator U1; The output of comparator U1 links to each other with the negative pole of diode D1, and the positive pole of diode D1 links to each other with the output of electric current loop in the said led driver;
Under the situation of voltage greater than said the 4th predeterminated voltage of said dim signal; Comparator U1 output low level signal; Cause diode D1 conducting, the output level of electric current loop in the said led driver is dragged down, wherein; Said off signal is the low level signal of said comparator U1 output, said first pre-conditioned be that the voltage of said dim signal is greater than said the 4th predeterminated voltage; Voltage at said dim signal is not more than under the situation of said the 4th predeterminated voltage, and comparator U1 exports high level, causes diode D1 conducting to end, and said second pre-conditionedly is not more than said the 4th predeterminated voltage for the voltage of said dim signal.
Wherein, said control circuit specifically comprises:
Switch S C, negative circuit and current rectifying and wave filtering circuit;
First end of switch S C links to each other with first end of resistance R 3, the second end ground connection of switch S C, and the control end of said switch S C links to each other with the output of said negative circuit;
The input of said negative circuit links to each other with the output of said current rectifying and wave filtering circuit, and the input of said current rectifying and wave filtering circuit connects the two ends of Transformer Winding in the said led driver;
Be in when said led driver under the situation of off-mode; The input of said current rectifying and wave filtering circuit is a low level signal; After said negative circuit anti-phase, act on the control end of said switch S C, it is closed to control said switch S C, thereby drags down the current potential of resistance R 3 first ends; The voltage that detects the two ends of said Transformer Winding when said led driver is not less than under the situation of the 5th predeterminated voltage; The input of said current rectifying and wave filtering circuit is a high level; After said negative circuit anti-phase, act on the control end of said switch S C; Control said switch S C and break off, the voltage at the wherein said the 3rd pre-conditioned two ends for said Transformer Winding is not less than said the 5th predeterminated voltage.
Wherein, said switch S C is specially NPN transistor, and first end of said switch S C is that collector electrode, second end are that emitter and control end are base stage.
Wherein, said switch S C is specially N type metal-oxide-semiconductor, and first end of said switch S C is that source electrode and control end are grid for drain electrode, second end.
Can know via above-mentioned technical scheme; A kind of light adjusting circuit that adopts the embodiment of the invention to provide; Satisfying under the first pre-conditioned situation, the off signal of comparison circuit output makes the led driver shutdown, led driver this moment output current not; The switching signal of control circuit control transformation circuit output is a low level, makes electric current loop in the led driver not accept the control of switching signal.When satisfying under the second pre-conditioned situation, comparison circuit stops to export off signal, just satisfies second led driver when pre-conditioned and does not satisfy the 3rd pre-conditioned; This moment, the electric current loop output in the led driver was because circuit control without comparison, and institute is so that led driver begins to open machine, because before led driver opens machine; Led driver is pre-conditioned owing to not satisfying the 3rd; The control circuit still switching signal of control transformation circuit output is a low level, makes the feedback end of electric current loop not controlled by switching signal, so the current loop control led driver opens machine fast; The output current of led driver increases to the process of non-zero from zero like this; Led driver can not occur and open the problem that machine postpones, satisfy under the 3rd pre-conditioned situation, stop the control transformation circuit when control circuit detects led driver; Electric current loop is according to switching signal, and the output current of control led driver is big or small.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention 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 embodiments of the invention, for those of ordinary skills; Under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to the accompanying drawing that provides.
Fig. 1 is the structural representation of the disclosed first kind of light adjusting circuit of the embodiment of the invention;
The circuit diagram of a kind of light adjusting circuit that Fig. 2 provides for the embodiment of the invention;
The circuit diagram of another light adjusting circuit that Fig. 3 provides for the embodiment of the invention.
Embodiment
To combine the accompanying drawing in the embodiment of the invention below, the technical scheme in the embodiment of the invention is carried out clear, intactly description, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the present invention's protection.
Embodiment one
See also accompanying drawing 1, be the structural representation of the disclosed first kind of light adjusting circuit of the embodiment of the invention, this circuit can comprise: led driver 101, comparison circuit 102, control circuit 103 and change-over circuit 104;
Satisfy under the first pre-conditioned situation comparison circuit 102 output off signals at dim signal Vx;
Led driver 101 shuts down after receiving said off signal;
The inverting input of operational amplifier U3 links to each other with the output of an end, compensating circuit 1011 and the change-over circuit 104 of resistance R 4 respectively; The 6th predeterminated voltage Vf1 acts on the in-phase input end of operational amplifier U3; The in-phase input end that is operational amplifier U3 is the reference edge of electric current loop, and the output of operational amplifier U3 links to each other with the output of above-mentioned compensating circuit 1011 and comparison circuit 102 respectively; The other end of resistance R 4 links to each other with the end of resistance R S and the negative electrode of load LED lamp 1012 respectively, and the other end of resistance R S links to each other with the negative pole of polar capacitor C1, wherein; The inverting input of operational amplifier U3 is the feedback end of electric current loop; The in-phase input end of operational amplifier U3 is the reference edge of electric current loop, and the output of operational amplifier U3 is the output of electric current loop, wherein; Resistance R S is a sampling resistor, gathers the output current sampled signal of led driver 101.
In practical application, led driver 101 comprises a lot of circuit, and the embodiment of the invention is only write out the partial circuit relevant with the embodiment of the invention, but led driver 101 has more than and comprises above-mentioned current loop circuit.
Satisfying under the first pre-conditioned situation; Comparison circuit 102 output low level signals; And the output of comparator 102 links to each other with the output of electric current loop in the led driver 101; Comparison circuit 102 output low level signals drag down the output level of electric current loop, thereby cause not output current of led driver 101, promptly are in off-mode.Control circuit 103 detects led driver 101 for behind the off-mode, and the switching signal of control transformation circuit 104 outputs is a low level, and the feedback end of the electric current loop in the led driver 101 is not accepted the control of switching signal.
The different first pre-conditioned differences of the structure of circuit are specifically referring to embodiment two and embodiment three.
At this moment, if the low level signal of circuit 102 output drags down the voltage of the output of electric current loop without comparison, then electric current loop can be controlled the output current of led driver according to i.e. the 6th predeterminated voltage Vf1 of the signal of the signal of its feedback end and reference edge.
Satisfy under the second pre-conditioned situation at dim signal Vx, comparison circuit 102 stops to export off signal, because the switching signal that change-over circuit 104 is exported under the control of control circuit 103 is a low level; The feedback end of the electric current loop in the led driver 101 is not accepted the control of switching signal; The output current sampled signal that only is controlled by led driver 101, and this moment, led driver 101 was in off-mode, promptly the output current sampled signal is zero; Therefore; The feedback end of electric current loop is a low level, and causing the output of the electric current loop in the led driver 101 is high level, led driver 101 is in opens the machine state.
The different second pre-conditioned differences of the structure of circuit are specifically referring to embodiment two and embodiment three.
The above-mentioned machine that opens state is meant that the output current of led driver 101 is from the process of zero increase, the state of led driver in this process.
Detect led driver 101 at control circuit 103 and satisfy under the 3rd pre-conditioned situation, stop control transformation circuit 104, make led driver 101 be in the output current state;
Change-over circuit 104 converts dim signal to switching signal, and led driver 101 changes self output current size according to this switching signal.
Because this moment, comparison circuit 102 stops to export off signal, and control circuit 103 stops control transformation circuit 104; So the magnitude of voltage of electric current loop feedback end is followed the variation of dim signal and changed, just follow the variation of switching signal and change, along with the reduction of switching signal; Because the closed-loop adjustment of electric current loop; For the signal of the feedback end that makes electric current loop equals the signal (being the 6th above-mentioned predeterminated voltage Vf1) of its reference edge, the current value of led driver 101 outputs is also just big more, and vice versa; Just led driver 101 changes self output current size according to this switching signal.
Preferably, above-mentioned switching signal and dim signal are linear.Different the 3rd pre-conditioned differences of the structure of circuit are specifically referring to embodiment two and embodiment three.
The complete load 105 of also having drawn for Fig. 1.
A kind of light adjusting circuit that adopts the embodiment of the invention to provide is satisfying under the first pre-conditioned situation, and the off signal of comparison circuit output makes the led driver shutdown; Led driver this moment output current not, the switching signal of control circuit control transformation circuit output is a low level, makes electric current loop in the led driver not accept the control of switching signal; When satisfying under the second pre-conditioned situation, comparison circuit stops to export off signal, just satisfies second led driver when pre-conditioned and does not satisfy the 3rd pre-conditioned; This moment, the electric current loop output in the led driver was because circuit control without comparison, and institute is so that led driver begins to open machine, because before led driver opens machine; Led driver is pre-conditioned owing to not satisfying the 3rd; The control circuit still switching signal of control transformation circuit output is a low level, makes the feedback end of electric current loop not controlled by switching signal, so the current loop control led driver opens machine fast; The output current of led driver increases to the process of non-zero from zero like this; Led driver can not occur and open the problem that machine postpones, satisfy under the 3rd pre-conditioned situation, stop the control transformation circuit when control circuit detects led driver; Electric current loop is according to switching signal, and the output current of control led driver is big or small.
Embodiment two
See also Fig. 2, the circuit diagram of a kind of light adjusting circuit that provides for the embodiment of the invention, this circuit can comprise: led driver 201, comparison circuit 202, control circuit 203 and change-over circuit 204, wherein:
Led driver 201 specifically comprises: main circuit 2011 and current loop circuit 2012.
One end of Transformer Winding 20111 links to each other with the positive pole of diode D2; The negative pole of diode D2 links to each other with the anode of load LED lamp and the positive pole of capacitor C 1 respectively; The negative pole of capacitor C 1 links to each other with the other end of Transformer Winding 20111, and this end is held with being masked as.The two ends of Transformer Winding 20111 all link to each other with the input of control circuit 103.
Current loop circuit is identical with current loop circuit among the embodiment one, and wherein, the inverting input of operational amplifier U3 is the feedback end of electric current loop, and the output of operational amplifier U3 is the output of electric current loop.
In practical application; Led driver 101 comprises a lot of circuit; The embodiment of the invention is only write out the partial circuit relevant with the embodiment of the invention; But led driver 101 has more than and comprises above-mentioned main circuit and current loop circuit, and main circuit also comprises a lot of components and parts, but the present invention has only write out components and parts relevant with the embodiment of the invention and the annexation between them.
Draw for ease, the winding 20111 of the transformer that in Fig. 2, only drawn, transformer does not draw.
Comparison circuit 202 can comprise: comparator U1 and diode D1.
Dim signal Vx acts on the in-phase input end of comparator U1; The first predeterminated voltage Vr1 acts on the inverting input of comparator U1; The output of comparator U1 links to each other with the negative pole of diode D1, and the positive pole of diode D1 links to each other with the output of electric current loop in the led driver 201;
Voltage at this dim signal Vx is not more than under the situation of the above-mentioned first predeterminated voltage Vr1; Comparator U1 output low level signal; Cause diode D1 conducting, the output level of electric current loop in the led driver 201 is dragged down, wherein; Above-mentioned off signal is the low level signal of comparator U1 output, and first pre-conditionedly is not more than the first predeterminated voltage Vr1 for the voltage of dim signal Vx; Under the situation of voltage greater than the first predeterminated voltage Vr1 of dim signal Vx, comparator U1 exports high level, causes diode D1 conducting to end, wherein, second pre-conditioned be that the voltage of dim signal Vx is greater than the first predeterminated voltage Vr1.
Therefore; The scope of supposing dim signal Vx is set [V1, V2], and during the maximum current of corresponding led driver 101 outputs of V2; Subclass [Vr1; V2] in the electric current of a non-zero of equal corresponding led driver 101 outputs of each element, and equal corresponding led driver 101 output currents of all elements in the subclass [V1, Vr1] are zero.
Change-over circuit 204 can comprise: resistance R 1, resistance R b1, resistance R b2 and operational amplifier U2.
The inverting input of operational amplifier U2 links to each other with the end of resistance R b1 and the end of resistance R b2 respectively; The second predeterminated voltage Vf2 acts on the in-phase input end of operational amplifier U2; The output of operational amplifier U2 links to each other with an end of resistance R 1 and the other end of resistance R b2 respectively; The other end of resistance R 1 links to each other with the feedback end of electric current loop in the said led driver, and said dim signal Vx acts on the other end of resistance R b1.
Wherein, Relation between the output voltage V u2 of operational amplifier U2 and the dim signal Vx is the anti-phase proportionate relationship; Be specially
wherein, voltage Vu2 is input to the feedback end of the electric current loop of led driver through output resistance R1.
Said control circuit specifically comprises: switch S C, negative circuit 2031 and current rectifying and wave filtering circuit 2032.
The end of switch S C links to each other with the output of operational amplifier U2, the other end ground connection of switch S C, and the control end of switch S C links to each other with the output of negative circuit 2031;
The input of negative circuit 2031 links to each other with the output of rectifying and wave-filtering electricity 2032, and the input of said current rectifying and wave filtering circuit connects the two ends of Transformer Winding in the said led driver;
Be in when led driver 101 under the situation of off-mode, the two ends of above-mentioned Transformer Winding 1011 are low level signal, after negative circuit 2031 anti-phases, act on the control end of switch S C, and control switch SC is closed; Voltage when the two ends that detect Transformer Winding 1011 is not less than under the situation of the 3rd predeterminated voltage, and the input of current rectifying and wave filtering circuit 2032 is a high level, after negative circuit 2031 anti-phases, acts on the control end of switch S C, and control switch SC breaks off.
Wherein, the 3rd in the embodiment of the invention pre-conditionedly is not less than above-mentioned the 3rd predeterminated voltage for the voltage at two ends that detects said Transformer Winding.In the present embodiment, the input of control circuit 203 connects the winding of transformer in the main circuit, when the main circuit of led driver is in off-mode; The winding voltage of its transformer is zero; Voltage behind the current rectifying and wave filtering circuit 2032 in control circuit 203 also is low level signal, converts the low level signal behind the rectifying and wave-filtering into high level through negative circuit 2031, and control switch Sc conducting; Control transformation circuit output low level signal; When led driver just began output current, the voltage ratio at the winding two ends of transformer was lower, after led driver starts a period of time; Be after the voltage at the two ends of said Transformer Winding is not less than above-mentioned the 3rd predeterminated voltage, switch S c is closed.
Embodiment three
See also Fig. 3, the circuit diagram of another light adjusting circuit that provides for the embodiment of the invention, this circuit can comprise: led driver 201, change-over circuit 301, comparison circuit 302 and control circuit 203, wherein:
Change-over circuit 301 can be resistance R 3.
The output of control circuit 303 links to each other with first end of resistance R 3, and dim signal Vx acts on first end of resistance R 3, and second end of resistance R 3 links to each other with the feedback end of electric current loop in the led driver 101.
Different with two kinds of change-over circuits of embodiment is not to be input to the feedback end of electric current loop after change-over circuit 301 is not changed dim signal Vx, but directly to be input to the feedback end of electric current loop through resistance R 3.
Comparator U1 and diode D1;
Dim signal Vx acts on the inverting input of comparator U1; The 4th predeterminated voltage Vr2 acts on the in-phase input end of comparator U1; The output of comparator U1 links to each other with the negative pole of diode D1, and the positive pole of diode D1 links to each other with the output of electric current loop in the said led driver;
Under the situation of voltage of dim signal Vx greater than above-mentioned the 4th predeterminated voltage Vr2; Comparator U1 output low level signal; Cause diode D1 conducting, the output level of electric current loop in the led driver 101 is dragged down, wherein; This low level signal is an off signal, among the embodiment one first pre-conditioned be that the voltage of said dim signal is greater than above-mentioned the 4th predeterminated voltage Vr2; Voltage at dim signal Vx is not more than under the situation of above-mentioned the 4th predeterminated voltage Vr2, and comparator U1 exports high level, causes diode D1 conducting to end, and second pre-conditionedly is not more than above-mentioned the 4th predeterminated voltage for the voltage of dim signal Vx.
Dim signal Vx is connected the inverting input of comparator U1 in the comparison circuit in the present embodiment, and the dim signal Vx among the embodiment two is connected the in-phase input end of comparison circuit.
Switch S C, negative circuit 2031 and current rectifying and wave filtering circuit 2032;
First end of switch S C links to each other with first end of resistance R 3, the second end ground connection of switch S C, and the control end of said switch S C links to each other with the output of negative circuit 3031;
The input of negative circuit 3031 links to each other with current rectifying and wave filtering circuit 3032, and the input of current rectifying and wave filtering circuit 3032 connects the two ends of Transformer Winding in the led driver 101.
Be in when led driver 101 under the situation of off-mode, the input of current rectifying and wave filtering circuit 3032 is a low level signal, after negative circuit 3031 anti-phases, acts on the control end of switch S C, and control switch SC is closed, thereby drags down the current potential of resistance R 3 first ends; The voltage that detects the two ends of above-mentioned Transformer Winding when led driver 101 is not less than under the situation of the 5th predeterminated voltage; The input of current rectifying and wave filtering circuit 3032 is a high level; After negative circuit 3031 anti-phases, act on the control end of switch S C; Control switch SC breaks off, and wherein, the voltage at the 3rd pre-conditioned two ends for said Transformer Winding is not less than above-mentioned the 5th predeterminated voltage.
Switch S C can be NPN transistor, and wherein, first end of switch S C is that collector electrode, second end are that emitter and control end are base stage.
Switch S C can also be N type metal-oxide-semiconductor.Wherein, first end of switch S C is that source electrode and control end are grid for drain electrode, second end.
In the embodiment of the invention, suppose that the span of dim signal Vx is set [V1, V2], and the maximum current of the corresponding led driver output of V1, the output current of [Vr2, V2] corresponding led driver is zero so.Therefore, in the comparison circuit of the embodiment of the invention, dim signal Vx is connected the inverting input of comparator U1, and the 4th predeterminated voltage Vr2 is connected the normal phase input end of comparator U1.As dim signal Vx during greater than the 4th predeterminated voltage Vr2, led driver 101 shutdown, output current is zero, when making dim signal Vx in [Vr2, V2] interval, output current is zero.And because dim signal is directly inputted to the feedback end of electric current loop through output resistance R1, like this, when dim signal Vx increased, through the effect of electric current loop, the output current of led driver can reduce thereupon.
Each embodiment adopts the mode of going forward one by one to describe in this specification, and what each embodiment stressed all is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.For the disclosed device of embodiment, because it is corresponding with the embodiment disclosed method, so description is fairly simple, relevant part is partly explained referring to method and is got final product.
The method of describing in conjunction with embodiment disclosed herein or the step of algorithm can be directly with the software modules of hardware, processor execution, and perhaps the combination of the two is implemented.Software module can place the storage medium of any other form known in random asccess memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or the technical field.
To the above-mentioned explanation of the disclosed embodiments, make this area professional and technical personnel can realize or use the present invention.Multiple modification to these embodiment will be conspicuous concerning those skilled in the art, and defined General Principle can realize under the situation that does not break away from the spirit or scope of the present invention in other embodiments among this paper.Therefore, the present invention will can not be restricted to these embodiment shown in this paper, but will meet and principle disclosed herein and features of novelty the wideest corresponding to scope.
Claims (9)
1. a light adjusting circuit is characterized in that, comprising: led driver, comparison circuit, control circuit and change-over circuit;
Satisfy under the first pre-conditioned situation said comparison circuit output off signal at dim signal;
Said led driver shuts down after receiving said off signal;
After said control circuit detected said led driver and is off-mode, the switching signal of controlling said change-over circuit output was a low level, so that said change-over circuit stops to control the electric current loop in the said led driver;
Satisfy under the second pre-conditioned situation at said dim signal; Said comparison circuit stops to export said off signal; Detecting said led driver at said control circuit does not satisfy under the 3rd pre-conditioned situation; The switching signal of controlling said change-over circuit output is a low level, makes said change-over circuit stop to control the electric current loop in the said led driver, said led driver is in opens the machine state;
Detect said led driver at said control circuit and satisfy under the 3rd pre-conditioned situation, stop to control said change-over circuit, make said led driver be in the output current state;
Said change-over circuit converts dim signal to switching signal, and said led driver changes the size of output current according to said switching signal.
2. according to the said light adjusting circuit of claim 1, it is characterized in that said change-over circuit specifically comprises:
Resistance R 1, resistance R b1, resistance R b2 and operational amplifier U2;
The inverting input of operational amplifier U2 links to each other with the end of resistance R b1 and the end of resistance R b2 respectively; Second predeterminated voltage acts on the in-phase input end of operational amplifier U2; The output of operational amplifier U2 links to each other with an end of resistance R 1 and the other end of resistance R b2 respectively; The other end of resistance R 1 links to each other with the feedback end of electric current loop in the said led driver, and said dim signal acts on the other end of resistance R b1.
3. according to claim 1 or 2 said light adjusting circuits, it is characterized in that said comparison circuit specifically comprises:
Comparator U1 and diode D1;
Said dim signal acts on the in-phase input end of comparator U1; First predeterminated voltage acts on the inverting input of comparator U1; The output of comparator U1 links to each other with the negative pole of diode D1, and the positive pole of diode D1 links to each other with the output of electric current loop in the said led driver;
Voltage at said dim signal is not more than under the situation of said first predeterminated voltage; Comparator U1 output low level signal; Cause diode D1 conducting, the output level of electric current loop in the said led driver is dragged down, wherein; Said off signal is the low level signal of comparator U1 output, and said first pre-conditionedly is not more than said first predeterminated voltage for the voltage of said dim signal; Under the situation of voltage greater than said first predeterminated voltage of said dim signal, comparator U1 exports high level, causes diode D1 conducting to end, wherein, said second pre-conditioned be that the voltage of said dim signal is greater than said first predeterminated voltage.
4. according to the said light adjusting circuit of claim 2, it is characterized in that said control circuit specifically comprises:
Switch S C, negative circuit and current rectifying and wave filtering circuit;
The end of switch S C links to each other with the output of operational amplifier U2, the other end ground connection of switch S C, and the control end of said switch S C links to each other with the output of said negative circuit;
The input of said negative circuit links to each other with the output of said current rectifying and wave filtering circuit, and the input of said current rectifying and wave filtering circuit connects the two ends of Transformer Winding in the said led driver;
Be in when said led driver under the situation of off-mode, said Transformer Winding two ends are low level signal, after said negative circuit anti-phase, act on the control end of said switch S C, and it is closed to control said switch S C; Voltage when the two ends that detect said Transformer Winding is not less than under the situation of the 3rd predeterminated voltage; The input of said current rectifying and wave filtering circuit is a high level; After said negative circuit anti-phase, act on the control end of said switch S C; Control said switch S C and break off, wherein, the said the 3rd pre-conditioned voltage for the two ends that detect said Transformer Winding is not less than said the 3rd predeterminated voltage.
5. according to the said light adjusting circuit of claim 1, it is characterized in that said change-over circuit is specially:
Resistance R 3;
The output of said control circuit links to each other with first end of resistance R 3, and said dim signal acts on first end of resistance R 3, and second end of resistance R 3 links to each other with the feedback end of electric current loop in the said led driver.
6. according to claim 1 or 5 said light adjusting circuits, it is characterized in that said comparison circuit specifically comprises:
Comparator U1 and diode D1;
Said dim signal acts on the inverting input of comparator U1; Said the 4th predeterminated voltage acts on the in-phase input end of comparator U1; The output of comparator U1 links to each other with the negative pole of diode D1, and the positive pole of diode D1 links to each other with the output of electric current loop in the said led driver;
Under the situation of voltage greater than said the 4th predeterminated voltage of said dim signal; Comparator U1 output low level signal; Cause diode D1 conducting, the output level of electric current loop in the said led driver is dragged down, wherein; Said off signal is the low level signal of said comparator U1 output, said first pre-conditioned be that the voltage of said dim signal is greater than said the 4th predeterminated voltage; Voltage at said dim signal is not more than under the situation of said the 4th predeterminated voltage, and comparator U1 exports high level, causes diode D1 conducting to end, and said second pre-conditionedly is not more than said the 4th predeterminated voltage for the voltage of said dim signal.
7. according to the said light adjusting circuit of claim 5, it is characterized in that said control circuit specifically comprises:
Switch S C, negative circuit and current rectifying and wave filtering circuit;
First end of switch S C links to each other with first end of resistance R 3, the second end ground connection of switch S C, and the control end of said switch S C links to each other with the output of said negative circuit;
The input of said negative circuit links to each other with the output of said current rectifying and wave filtering circuit, and the input of said current rectifying and wave filtering circuit connects the two ends of Transformer Winding in the said led driver;
Be in when said led driver under the situation of off-mode; The input of said current rectifying and wave filtering circuit is a low level signal; After said negative circuit anti-phase, act on the control end of said switch S C, it is closed to control said switch S C, thereby drags down the current potential of resistance R 3 first ends; The voltage that detects the two ends of said Transformer Winding when said led driver is not less than under the situation of the 5th predeterminated voltage; The input of said current rectifying and wave filtering circuit is a high level; After said negative circuit anti-phase, act on the control end of said switch S C; Control said switch S C and break off, the voltage at the wherein said the 3rd pre-conditioned two ends for said Transformer Winding is not less than said the 5th predeterminated voltage.
8. according to claim 4 or 7 said light adjusting circuits, it is characterized in that said switch S C is specially NPN transistor, first end of said switch S C is that collector electrode, second end are that emitter and control end are base stage.
9. according to claim 4 or 7 said light adjusting circuits, it is characterized in that said switch S C is specially N type metal-oxide-semiconductor, first end of said switch S C is that source electrode and control end are grid for drain electrode, second end.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210140508.2A CN102665344B (en) | 2012-05-08 | 2012-05-08 | Dimming circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210140508.2A CN102665344B (en) | 2012-05-08 | 2012-05-08 | Dimming circuit |
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| CN102665344B CN102665344B (en) | 2014-08-27 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101631409A (en) * | 2009-08-20 | 2010-01-20 | 英飞特电子（杭州）有限公司 | Pulse-width modulation (PWM) light-adjusting circuit for light-emitting diode (LED) |
| CN201623894U (en) * | 2010-01-28 | 2010-11-03 | 中山兴瀚科技有限公司 | Constant current source driver |
| US20110062877A1 (en) * | 2009-09-14 | 2011-03-17 | System General Corporation | Offline led lighting circuit with dimming control |
| TW201136126A (en) * | 2010-04-09 | 2011-10-16 | Acbel Polytech Inc | LED light power supply with light dimming function |
| CN202172518U (en) * | 2011-08-04 | 2012-03-21 | 英飞特电子（杭州）有限公司 | Pulse width modulation burst dimming device |
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- 2012-05-08 CN CN201210140508.2A patent/CN102665344B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101631409A (en) * | 2009-08-20 | 2010-01-20 | 英飞特电子（杭州）有限公司 | Pulse-width modulation (PWM) light-adjusting circuit for light-emitting diode (LED) |
| US20110062877A1 (en) * | 2009-09-14 | 2011-03-17 | System General Corporation | Offline led lighting circuit with dimming control |
| CN201623894U (en) * | 2010-01-28 | 2010-11-03 | 中山兴瀚科技有限公司 | Constant current source driver |
| TW201136126A (en) * | 2010-04-09 | 2011-10-16 | Acbel Polytech Inc | LED light power supply with light dimming function |
| CN202172518U (en) * | 2011-08-04 | 2012-03-21 | 英飞特电子（杭州）有限公司 | Pulse width modulation burst dimming device |
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| CN102665344B (en) | 2014-08-27 |
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