CN102340907A - Light emitting diode (LED) controller having function of flicker removal, LED flicker removal circuit and related method - Google Patents
Light emitting diode (LED) controller having function of flicker removal, LED flicker removal circuit and related method Download PDFInfo
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- CN102340907A CN102340907A CN2010102371192A CN201010237119A CN102340907A CN 102340907 A CN102340907 A CN 102340907A CN 2010102371192 A CN2010102371192 A CN 2010102371192A CN 201010237119 A CN201010237119 A CN 201010237119A CN 102340907 A CN102340907 A CN 102340907A
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Abstract
The invention provides a light emitting diode (LED) controller having a function of flicker removal, an LED flicker removal circuit and a related method. The LED controller having the function of the flicker removal comprises a duty ratio counting circuit, the LED flicker removal circuit and a dimming circuit, wherein the duty ratio counting circuit is used for receiving a pulse width modulation (PWM) signal and generating an operating input signal to represent the duty ratio of the PWM signal; the LED flicker removal circuit is used for receiving the operating input signal and generating an operating output signal to filter noise of the operating input signal; and the dimming circuit is used for receiving the operating output signal and generating a dimming signal to control an LED circuit, wherein the operating output signal retains a previous operating output signal and is unchanged when the change value of the operating input signal is not greater than a hysteresis critical value, and the operating output signal follows the current operating input signal when the change value of the operation input signal is greater than the hysteresis critical value.
Description
Technical field
The present invention relates to a kind of light-emitting diode (LED) controller of removing flashing function that has, be meant that especially a kind of hysteresis effect of utilizing is to remove the led controller of flicker.The present invention also removes flashing circuit relevant for a kind of LED, removes the method for flicker with led circuit.
Background technology
Fig. 1 shows the circuit of prior art, led controller 1 control led circuit 4.The brightness of LED can be adjusted than (duty ratio) according to the work of PWM (PWM) signal 2, and it is higher than more to work, and LED is just bright more.In Fig. 1 circuit; The calculating of work ratio is in working than counting circuit 110, to utilize the higher time pulse signal CLK 3 of frequency to figure the pulse bandwidth and the cycle of PWM signal 2; Thereby the work that calculates produces light modulation signal brightness with adjustment led circuit 4 according to this n position work than digital signals by light adjusting circuit 11 than (digital signal with the n position is represented).Yet as shown in Figure 2, actual PWM signal 2 has the phenomenon of distortion (skew) in conducting and the process of closing, and time pulse signal CLK 3 also has acute situation of jumping (jitter).Situation is jumped in the distortion phenomenon of this PWM signal 2 and the play of time pulse signal CLK 3, can cause the result of calculation of work ratio that error is arranged.For example, keep identical PWM signal 2 originally and possibly therefore calculate the different working ratio, and make the light modulation signal unstable, and then cause the flicker of led circuit 4 because of the error of this calculating.
In view of this, the present invention proposes a kind of led controller and LED removal flashing circuit and correlation technique of removing flashing function that have promptly to the deficiency of above-mentioned prior art.
Summary of the invention
One of the object of the invention is to overcome the deficiency and the defective of prior art, proposes a kind of led controller of removing flashing function that has.
Another object of the present invention is to, provide a kind of LED to remove flashing circuit.
A purpose more of the present invention is, provides a kind of LED to remove flickering method.
For reaching above-mentioned purpose,, the invention provides a kind of led controller of removing flashing function that has with regard to one of them viewpoint speech; Comprise: counting circuit is compared in work; Receive a PWM (PWM) signal and calculate its work ratio,, represent the work ratio of this PWM signal to produce a work input signal; LED removes flashing circuit, receives this work input signal, and produces a work output signal to filter the noise of this work input signal; And light adjusting circuit, receive this work output signal, and, produce a light modulation signal, with the control led circuit according to this work output signal; Wherein, when the change of work input signal was not more than a magnetic hysteresis critical value, this work output signal remained unchanged; When the change of work input signal during greater than this magnetic hysteresis critical value, this work output signal remains unchanged after following work input signal at that time, up to the change of next one work input signal greater than this magnetic hysteresis critical value.
In a kind of therein enforcement kenel, have the led controller of removing flashing function and also comprise a magnetic hysteresis critical value setting circuit, with dynamic setting magnetic hysteresis critical value.Can comprise a magnetic hysteresis decision-making circuit in this magnetic hysteresis critical value setting circuit, determine the magnetic hysteresis critical value according to the cycle of PWM signal or according to the work input signal.
With regard to another viewpoint speech; The invention provides a kind of LED and remove flashing circuit; It receives a work input signal, and produces a work output signal to filter the noise of this work input signal, and this LED removes flashing circuit and comprises: decision circuitry; Receive this work input signal and judge that its change whether greater than a magnetic hysteresis critical value, then produces one in this way and judges signal; And output generation circuit; Be controlled by this judgement signal, export this work input signal or keep this work output signal constant with selection, wherein; When the change of work input signal is not more than this magnetic hysteresis critical value; This work output signal keeps last work output signal constant, when the change of work input signal during greater than this magnetic hysteresis critical value, after this work output signal is followed work input signal at that time; Remain unchanged, up to the change of next one work input signal greater than this magnetic hysteresis critical value.
Remove in flashing circuit at the above LED, this output generation circuit can comprise the selection circuit, is controlled by to judge signal and select:
(1) work input signal or
(2) (a) this work output signal or (b) and the signal of this work output signal equal value, wherein " signal of this work output signal equal value " can be through getting with a latch circuit storage work input signal.
This output generation circuit also can comprise a latch circuit, is controlled by to judge signal and store this work input signal, and the output of this latch circuit is as this work output signal.
This output generation circuit also can comprise counting circuit about in the of, counts up and down according to the comparative result of above-mentioned (one) (two) signal, and the output of counting circuit is as this work output signal up and down.
Remove in the flashing circuit at the above LED, this decision circuitry can comprise: the absolute difference circuit receives above-mentioned (one) (two) signal, and produces an absolute difference signal according to both differences of (one) (two); And magnetic hysteresis critical value comparison circuit, it is this absolute difference signal and this magnetic hysteresis critical value relatively, and should judge signal according to the comparative result generation.
Above-mentioned absolute difference circuit can comprise: numerical value comparison circuit, more above-mentioned (one) (two) signal; Subtraction circuit, its first termination is received minuend, and second termination is received subtrahend, and its output produces aforementioned absolute difference signal; And the selection circuit, according to the comparative result of this numerical value comparison circuit, decision is with in above-mentioned (one) (two) signal, and what person's input subtraction circuit first end is as minuend, and what person's input subtraction circuit second end is as subtrahend.
Just another viewpoint is sayed again, the invention provides a kind of LED and removes flickering method, comprises: receive a PWM signal and calculate its work ratio, to produce a work input signal, represent the work ratio of this PWM signal; Receive this work input signal, and produce a work output signal to filter the noise of this work input signal; And receive this work output signal, and, produce a light modulation signal according to this work output signal, with the control led circuit; Wherein, when the change of work input signal was not more than a magnetic hysteresis critical value, this work output signal remained unchanged; When the change of work input signal during greater than this magnetic hysteresis critical value, this work output signal remains unchanged after following work input signal at that time, up to the change of next one work input signal greater than this magnetic hysteresis critical value.
Explain in detail through specific embodiment below, when the effect that is easier to understand the object of the invention, technology contents, characteristics and is reached.
Description of drawings
Fig. 1 marks the led controller circuit framework of prior art;
Fig. 2 marks in the signal waveform of Fig. 1, and the PWM signal is distorted (skew), the acute situation of jumping (jitter) of time pulse signal CLK in conducting and the process of closing;
Fig. 3 shows that the present invention has an embodiment of the led controller of removing flashing function;
Fig. 4 shows that LED removes the primary structure of flashing circuit 120;
Fig. 5 shows that LED removes an embodiment of flashing circuit 120;
Fig. 6 shows that LED removes another embodiment of flashing circuit 120;
Fig. 7 marks an embodiment of latch circuit 121;
Fig. 8 shows that LED removes another embodiment of flashing circuit 120;
Fig. 9 explains the hardware embodiment of decision circuitry 122;
Figure 10 shows an embodiment of the critical value comparison circuit 125 that stagnates;
Figure 11 shows the hardware embodiment of absolute difference circuit 124;
Figure 12 shows the embodiment more specifically of absolute difference circuit 124;
Figure 13 shows another embodiment of output generation circuit 123;
Figure 14, shown in 15, can be through the dynamic adjustment magnetic hysteresis critical value HYS of magnetic hysteresis critical value setting circuit 130;
Figure 16 shows an embodiment of magnetic hysteresis critical value setting circuit 130;
Figure 17-19 shows several embodiment of magnetic hysteresis decision-making circuit.
Symbol description among the figure
1,10 led controller
2 PWM signals
3,3a time pulse signal CLK
4 led circuits
11 light adjusting circuits
Counting circuit is compared in 110 work
120 LED remove flashing circuit
121 latch circuits
122 decision circuitry
123 output generation circuits
1231 select circuit
1232 latch circuits
1233 up-down counter
124 absolute difference circuit
1241 comparators
1242 select circuit
1243 subtraction circuits
1244 first selectors
1245 second selectors
1246 inverters
1248 adders
125 magnetic hysteresis critical value comparison circuits
130 magnetic hysteresis critical value setting circuit
131 computation of Period circuit
132 magnetic hysteresis decision-making circuits
1321 lookup table circuits
1322 decoding circuits
1323 reading circuits
DIF absolute difference signal
The DT0 signal
The Duty-IN input signal of working
The Duty-OUT output signal of working
The PRD period signal
HYS magnetic hysteresis critical value
Embodiment
Major technique thought of the present invention is to utilize magnetic hysteresis to judge, to remove the flicker problem of led circuit.
See also Fig. 3, show that the present invention has an embodiment of the led controller of removing flashing function.As shown in the figure; Work in the PWM signal 2 input led controllers 10 is than counting circuit 110; The work ratio of PWM signal 2 is calculated in work with time pulse signal CLK 3 as shown in Figure 2 (can be inner the generation or outside input) than counting circuit 110; And this work represented than with n bit digital form, that is work input signal Duty-IN.For example, the operating time of supposing PWM signal 2 is t, and the cycle is T, then
Work input signal Duty-IN=(t/T) * 2
n
This work input signal Duty-IN inputs to LED and removes flashing circuit 120.LED removes flashing circuit 120 according to work input signal Duty-IN; Output services output signal Duty-OUT; The output signal Duty-OUT that wherein works also is n bit digital form, and has the magnetic hysteresis relation between work input signal Duty-IN and work output signal Duty-OUT, removes flashing circuit 120 controls by LED; Wherein, When the change of work input signal Duty-IN was not more than the magnetic hysteresis critical value HYS (Fig. 3 is not shown, will detail in the back literary composition) of a setting, this work output signal Duty-OUT remained unchanged; When the change of work input signal Duty-IN during greater than magnetic hysteresis critical value HYS, after work output signal Duty-OUT follows work input signal Duty-IN at that time, remain unchanged, up to the change of next one work input signal greater than magnetic hysteresis critical value HYS.For example, suppose that magnetic hysteresis critical value HYS is set at 1, following signal then possibly take place change:
| Time | Duty-IN | Fiducial value | Change | Duty-OUT |
| T0 | 196 | 196 | n/a | 196 |
| T1 | 197 | 196 | 1 | 196 |
| T2 | 198 | 196 | 2 | 198 |
| T3 | 197 | 198 | 1 | 198 |
| T4 | 199 | 198 | 1 | 198 |
| T5 | 200 | 198 | 2 | 200 |
| T6 | 205 | 200 | 5 | 205 |
That is, only in the change of work input signal Duty-IN during greater than magnetic hysteresis critical value HYS, work output signal Duty-OUT just follow at that time work input signal Duty-IN (see time T 2, T5, T6).
Fig. 4 shows that LED removes the primary structure of flashing circuit 120, wherein comprises decision circuitry 122 and output generation circuit 123.Decision circuitry 122 receives work input signal Duty-IN and judges that its change whether greater than magnetic hysteresis critical value HYS, then produces one in this way and judges signal.Output generation circuit 123 is controlled by this judgement signal, and selects this work input signal Duty-IN of output or keep this work output signal Duty-OUT constant.Magnetic hysteresis critical value HYS can be a preset fixed value, or the numerical value that can dynamically adjust.About the details of decision circuitry 122 and magnetic hysteresis critical value HYS adjustment how dynamically, hold the back and detail.
Fig. 5 shows that LED removes a kind of embodiment of flashing circuit 120; The output generation circuit 123 of Fig. 4 is in the present embodiment to select circuit 1231 to embody; Its first input end reception work input signal Duty-IN; The second input reception work output signal Duty-OUT, and selection circuit 1231 is controlled by the judgement signal and selects its output.Decision circuitry 122 receives work input signal Duty-IN and work output signal Duty-OUT, and according to the difference of work input signal Duty-IN with work output signal Duty-OUT, HYS compares with the magnetic hysteresis critical value, whether exports the judgement signal with decision.
Among Fig. 5 embodiment; With work output signal Duty-OUT input decision circuitry 122 and the purpose of selecting circuit 1231; The fiducial value that the work output signal Duty-OUT of a time point changes as calculating before being, but this fiducial value is not limited to be necessary for the work output signal Duty-OUT of last time point.See also Fig. 6, also can work input signal Duty-IN be deposited in the latch circuit 121, and with the output DT0 of this latch circuit 121 as fiducial value, input decision circuitry 122 with select circuit 1231.Latch circuit 121 is only being judged that signal enables the following input signal Duty-IN that just will work and deposits in it, and in other words signal DT0 promptly is equivalent to the work output signal Duty-OUT of last time point.
Fig. 8 shows that LED removes another embodiment of flashing circuit 120; The output generation circuit 123 of Fig. 4 embodies with latch circuit 1232 in the present embodiment; This latch circuit 1232 for example can be but is not limited to D type flip-flop; It is judging that signal enables to store work input signal Duty-IN down, and the output of latch circuit 1232 is then as this work output signal Duty-OUT.Though latch circuit 1232 is similar with connected mode with the structure of latch circuit 121; But effect is different; Latch circuit 121 is in order to store work input signal Duty-IN as fiducial value; 1232 of latch circuits are that to select output signal in order to control be present work input signal Duty-IN, or remain work output signal Duty-OUT originally.
(1) work input signal Duty-IN, with
(2) (a) work output signal Duty-OUT or (b) and the signal DT0 of this work output signal Duty-OUT equal value,
And produce an absolute difference signal DIF according to both differences of (one) (two); Magnetic hysteresis critical value comparison circuit 125 is this absolute difference signal DIF and this magnetic hysteresis critical value HYS relatively, and should judge signal according to the comparative result generation.Wherein, magnetic hysteresis critical value comparison circuit 125 for example can be but is not limited to the comparator 125 (comparator 125 can be hysteresis comparator or general comparator) of Figure 10.
Figure 11 shows the hardware embodiment of absolute difference circuit 124; Absolute difference circuit 124 comprises comparator 1241 (comparator 1241 can be hysteresis comparator or general comparator), selects circuit 1242 and subtraction circuit 1243, wherein comparator 1241 more above-mentioned () (two) two signals in the present embodiment; Select the comparative result of circuit 1242, and decision is with the anode of what person's input subtraction circuit 1243 in (one) (two) two signals, the negative terminal of another person's input subtraction circuit 1243 according to comparator 1241; The output of subtraction circuit 1243 is said absolute difference signal DIF.
Figure 12 shows the embodiment more specifically of absolute difference circuit 124.Shown in figure 12; Select to comprise first selector 1244, second selector 1245 in the circuit 1242; As work input signal Duty-IN during greater than work output signal Duty-OUT; The output of comparator 1241 makes first selector 1244 select work input signal Duty-IN and second selector 1245 selects work output signal Duty-OUT as output signal, when work input signal Duty-IN then opposite during less than work output signal Duty-OUT.Subtraction circuit 1243 comprises inverter 1246 and adder 1248; The output signal of second selector 1245 by the output signal addition of adder 1248 with first selector 1244, will produce the absolute difference signal DIF of work input signal Duty-IN and work output signal Duty-OUT through inverter 1246 backs.
Figure 13 shows another embodiment of output generation circuit 123; The output generation circuit 123 of Fig. 4 is in the present embodiment with counter 1233 embodiments up and down; This up-down counter 1233 is judging that signal enables down; Output according to comparator 1241 is counted up and down, and its output is as work output signal Duty-OUT.Under the arrangement mode of present embodiment; When work input signal Duty-IN acute variation; Work output signal Duty-OUT will progressively change and can immediate response, so can make the unlikely variation of brightness of led circuit 4 too violent, and its signal changes for example maybe be as follows:
| Time | Duty-IN | Fiducial value | Change | Duty-OUT |
| T0 | 196 | 196 | n/a | 196 |
| T1 | 205 | 196 | 9 | 197 |
| T2 | 205 | 197 | 8 | 198 |
| T3 | 205 | 198 | 7 | 199 |
| T4 | 205 | 199 | 6 | 200 |
| T5 | 205 | 200 | 5 | 201 |
| T6 | 205 | 201 | 4 | 202 |
| T7 | 205 | 202 | 3 | 203 |
| T8 | 205 | 203 | 2 | 204 |
| T9 | 205 | 204 | 1 | 204 |
Wherein, Up-down counter 1233 can be accepted the time pulse signal identical or different with integrated circuit; Accept the time pulse signal different with integrated circuit like counter 1233 up and down, then going up work the down variable quantity of output signal Duty-OUT of each chronomere in the table can not be 1.
According to the present invention, magnetic hysteresis critical value HYS can be a preset fixed value, or the numerical value that can dynamically adjust.Under the latter instance; Magnetic hysteresis critical value HYS for example can be set with artificial mode from the outside of led controller 10 by the user; Or, can decide by the cycle of detecting PWM signal 2 or according to work input signal Duty-IN through magnetic hysteresis critical value setting circuit 130 like Figure 14, shown in 15.In detail; Dynamically the reason possibility of adjustment magnetic hysteresis critical value HYS as follows: when the cycle of PWM signal 2 is longer; Play jumping (jitter) situation of its distortion (skew) phenomenon and time pulse signal CLK 3 is lower for the influence of flicker; When the cycle of PWM signal 2 more then influences higherly,, than the short period time, heighten magnetic hysteresis critical value HYS so can detect corresponding decision of the cycle of PWM signal 2 magnetic hysteresis critical value HYS; Or human eye is lower at the feeling ability of some brightness range, so can come corresponding decision magnetic hysteresis critical value HYS according to the in-scope of work input signal Duty-IN, for example heightens magnetic hysteresis critical value HYS in the more sensitive zone of human eye.
Figure 16 shows an embodiment of magnetic hysteresis critical value setting circuit 130, wherein comprises computation of Period circuit 131 and magnetic hysteresis decision-making circuit 132.Computation of Period circuit 131 receives PWM signal 2; And via inside produces or the outside time pulse signal CLK 3a that provides calculates PWM signal 2 cycle; Produce period signal PRD, wherein this time pulse signal CLK 3a can be for being same or different from the signal of time pulse signal CLK 3.Magnetic hysteresis decision-making circuit 132 receiving cycle signal PRD, and according to period signal PRD and corresponding decision magnetic hysteresis critical value HYS.For example, the operating time of supposing PWM signal 2 is t, and the cycle is T,
Work input signal Duty-IN=(t/T) * 2
n,
And when calculating with time pulse signal CLK 3a, the clock pulse number of cycle T is M, then for example can be set at
When M＞2
N+1, HYS=1
When 2
n＜M≤2
N+1, HYS=2
When 2
N-1＜M≤2
n, HYS=4
Or the like.
Decide magnetic hysteresis critical value HYS like magnetic hysteresis critical value setting circuit 130 according to work input signal Duty-IN, then can not need computation of Period circuit 131 in the magnetic hysteresis critical value setting circuit 130 and only need magnetic hysteresis decision-making circuit 132.
The magnetic hysteresis decision-making circuit for example can be the lookup table circuit 1321 shown in Figure 17-19, decoding circuit 1322 or reading circuit 1323 only.In lookup table circuit 1321 and decoding circuit 1322, the corresponding relation between predeterminable input and output signal.In a reading circuit 1323, can corresponding magnetic hysteresis critical value HYS as the address, be taken out in period signal PRD or work input signal Duty-IN (or part position of its tool meaning).Certainly, the magnetic hysteresis decision-making circuit also can be other any circuit.
Below to preferred embodiment the present invention being described, is the above, be merely to make those skilled in the art be easy to understand content of the present invention, and be not to be used for limiting interest field of the present invention.Under same spirit of the present invention, those skilled in the art can think and various equivalence changes.For example, replaceable to rise the signal meaning that edge and high levels are represented for to represent to fall edge and low level, only need the design of corresponding some circuit element of change; The up-down counting of counter can be done opposite arrangement; The magnetic hysteresis critical value can not only be arranged one, can also several; Shown in each embodiment circuit, can insert the element that does not influence the main meaning of signal, like other switch etc.; The input of each comparator is positive and negative can be exchanged, and only needs the signal processing mode of corresponding correction circuit to get final product.All this kind all can teaching according to the present invention be analogized and gets, and therefore, scope of the present invention should contain above-mentioned and other all equivalences change.
Claims (31)
1. one kind has the LED controller of removing flashing function, it is characterized in that, comprises:
Work receives a pulse width modulation signal and calculates its work ratio than counting circuit, to produce a work input signal, represents the work ratio of this pulse width modulation signal;
LED removes flashing circuit, receives this work input signal, and produces a work output signal to filter the noise of this work input signal; And
Light adjusting circuit receives this work output signal, and according to this work output signal, produces a light modulation signal, with the control led circuit;
Wherein, when the change of work input signal was not more than a magnetic hysteresis critical value, this work output signal remained unchanged;
When the change of work input signal during greater than this magnetic hysteresis critical value, this work output signal remains unchanged after following work input signal at that time, up to the change of next one work input signal greater than this magnetic hysteresis critical value.
2. the led controller with removal flashing function as claimed in claim 1, wherein, this LED removes flashing circuit and comprises:
Decision circuitry receives this work input signal and judges that its change whether greater than this magnetic hysteresis critical value, then produces one in this way and judges signal; And
Output generation circuit is controlled by this judgement signal, to select this work input signal of output or to keep this work output signal constant.
3. the led controller with removal flashing function as claimed in claim 2; Wherein, This output generation circuit comprises that one selects circuit; Its first input end receives this work input signal, and second input receives (a) this work output signal or (b) and the signal of this work output signal equal value, and this selection circuit is controlled by this judgement signal and selects its output.
4. the led controller with removal flashing function as claimed in claim 3; Wherein, this LED removes flashing circuit and also comprises: latch circuit, and it enables down at this judgement signal; Store this work input signal, the output of this latch circuit and this selection circuit second input couple.
5. the led controller with removal flashing function as claimed in claim 2, wherein, this output generation circuit comprises a latch circuit, and it enables to store this work input signal down at this judgement signal, and the output of this latch circuit is as this work output signal.
6. the led controller with removal flashing function as claimed in claim 2, wherein, this decision circuitry comprises:
The absolute difference circuit receives (a) this work output signal or (b) and the signal of this work output signal equal value of (one) this work input signal and (two), and produces an absolute difference signal according to both differences of (one) (two); And
Magnetic hysteresis critical value comparison circuit, it is this absolute difference signal and this magnetic hysteresis critical value relatively, and should judge signal according to the comparative result generation.
7. the led controller with removal flashing function as claimed in claim 6, wherein, this absolute difference circuit comprises:
Numerical value comparison circuit, relatively (a) this work output signal or (b) and the signal of this work output signal equal value of (one) this work input signal and (two);
Subtraction circuit, its first termination is received minuend, and second termination is received subtrahend, and its output produces aforementioned absolute difference signal; And
Select circuit, according to the comparative result of this numerical value comparison circuit, decision will
This work input signal input, with
(2) (a) this work output signal or (b) and among the signal of this work output signal equal value, what person's input subtraction circuit first end is as minuend, what person's input subtraction circuit second end is as subtrahend.
8. the led controller with removal flashing function as claimed in claim 7, wherein, this output generation circuit comprises:
Up-down counter, it enables to count up and down according to the comparative result of this numerical value comparison circuit down at this judgement signal, and its output is as the work output signal.
9. the led controller with removal flashing function as claimed in claim 1 wherein, also comprises: magnetic hysteresis critical value setting circuit, and with this magnetic hysteresis critical value of dynamic setting.
10. the led controller with removal flashing function as claimed in claim 9, wherein, this magnetic hysteresis critical value setting circuit comprises:
The computation of Period circuit receives this pulse width modulation signal and calculates its cycle, to produce the one-period signal of representing this pulse width modulation signal cycle; And
The magnetic hysteresis decision-making circuit is according to this this magnetic hysteresis critical value of period signal decision.
11. the led controller with removal flashing function as claimed in claim 9; Wherein, This magnetic hysteresis critical value setting circuit reception work input signal, and this magnetic hysteresis critical value setting circuit comprises a magnetic hysteresis decision-making circuit, according to this this magnetic hysteresis critical value of work input signal decision.
12. describedly have led controllers of removing flashing function like claim 10 or 11, wherein, this magnetic hysteresis decision-making circuit is lookup table circuit, decoding circuit or reading circuit only.
13. a LED removes flashing circuit, it receives a work input signal, and produces a work output signal to filter the noise of this work input signal, it is characterized in that this LED removes flashing circuit and comprises:
Decision circuitry receives this work input signal and judges that its change whether greater than a magnetic hysteresis critical value, then produces one in this way and judges signal; And
Output generation circuit is controlled by this judgement signal, and export this work input signal or keep this work output signal constant with selection,
Wherein, When the change of work input signal is not more than this magnetic hysteresis critical value; This work output signal keeps last work output signal constant, when the change of work input signal during greater than this magnetic hysteresis critical value, after this work output signal is followed work input signal at that time; Remain unchanged, up to the change of next one work input signal greater than this magnetic hysteresis critical value.
14. LED as claimed in claim 13 removes flashing circuit; Wherein, This output generation circuit comprises that one selects circuit; Its first input end receives this work input signal, and second input receives (a) this work output signal or (b) and the signal of this work output signal equal value, and this selection circuit is controlled by this judgement signal and selects its output.
15. LED as claimed in claim 14 removes flashing circuit; Wherein, this LED removes flashing circuit and also comprises: latch circuit, and it enables down at this judgement signal; Store this work input signal, the output of this latch circuit and this selection circuit second input couple.
16. LED as claimed in claim 13 removes flashing circuit, wherein, this output generation circuit comprises a latch circuit, and it enables to store this work input signal down at this judgement signal, and the output of this latch circuit is as this work output signal.
17. LED as claimed in claim 13 removes flashing circuit, wherein, this decision circuitry comprises:
The absolute difference circuit receives (a) this work output signal or (b) and the signal of this work output signal equal value of (one) this work input signal and (two), and produces an absolute difference signal according to both differences of (one) (two); And
Magnetic hysteresis critical value comparison circuit, it is this absolute difference signal and this magnetic hysteresis critical value relatively, and should judge signal according to the comparative result generation.
18. LED as claimed in claim 17 removes flashing circuit, wherein, this absolute difference circuit comprises:
Numerical value comparison circuit, relatively (a) this work output signal or (b) and the signal of this work output signal equal value of (one) this work input signal and (two);
Subtraction circuit, its first termination is received minuend, and second termination is received subtrahend, and its output produces aforementioned absolute difference signal; And
Select circuit, according to the comparative result of this numerical value comparison circuit, decision will
This work input signal input, with
(2) (a) this work output signal or (b) and among the signal of this work output signal equal value, what person's input subtraction circuit first end is as minuend, what person's input subtraction circuit second end is as subtrahend.
19. LED as claimed in claim 18 removes flashing circuit, wherein, this output generation circuit comprises:
Up-down counter, it enables to count up and down according to the comparative result of this numerical value comparison circuit down at this judgement signal, and its output is as the work output signal.
20. LED as claimed in claim 13 removes flashing circuit, wherein, also comprises: magnetic hysteresis critical value setting circuit, with this magnetic hysteresis critical value of dynamic setting.
21. LED as claimed in claim 20 removes flashing circuit, wherein, this magnetic hysteresis critical value setting circuit comprises:
The computation of Period circuit; Receive a pulse width modulation signal; Wherein aforementioned work input signal system than get, in the cycle of this this pulse width modulation signal of computation of Period circuit calculating, represents the one-period signal in this pulse width modulation signal cycle according to the work of this pulse width modulation signal with generation; And
The magnetic hysteresis decision-making circuit is according to this this magnetic hysteresis critical value of period signal decision.
22. LED as claimed in claim 20 removes flashing circuit, wherein, and this magnetic hysteresis critical value setting circuit reception work input signal, and this magnetic hysteresis critical value setting circuit comprises a magnetic hysteresis decision-making circuit, according to this this magnetic hysteresis critical value of work input signal decision.
23. remove flashing circuits like claim 21 or 22 described LED, wherein, this magnetic hysteresis decision-making circuit is lookup table circuit, decoding circuit or reading circuit only.
24. a LED removes flickering method, it is characterized in that, comprises:
Receive a pulse width modulation signal and calculate its work ratio,, represent the work ratio of this pulse width modulation signal to produce a work input signal;
Receive this work input signal, and produce a work output signal to filter the noise of this work input signal; And
Receive this work output signal, and, produce a light modulation signal, with the control led circuit according to this work output signal;
Wherein, when the change of work input signal was not more than a magnetic hysteresis critical value, this work output signal remained unchanged;
When the change of work input signal during greater than this magnetic hysteresis critical value, this work output signal remains unchanged after following work input signal at that time, up to the change of next one work input signal greater than this magnetic hysteresis critical value.
25. LED as claimed in claim 24 removes flickering method, wherein, this receives work input signal, and the step that produces a work output signal also comprises: store this work input signal.
26. LED as claimed in claim 24 removes flickering method, wherein, this receives work input signal, and the step that produces a work output signal comprises:
Receive this work input signal and judge that its change whether greater than a magnetic hysteresis critical value, then produces one in this way and judges signal; And
Judge signal according to this, to select this work input signal of output or to keep this work output signal constant.
27. LED as claimed in claim 26 removes flickering method, wherein, this receptions work input signal also judges that its step that whether changes greater than a magnetic hysteresis critical value comprises:
Receive (a) this work output signal or (b) and the signal of this work output signal equal value of (one) this work input signal and (two), and produce an absolute difference signal according to both differences of (one) (two); And
Relatively this absolute difference signal and this magnetic hysteresis critical value, and produce according to comparative result and should judge signal.
28. LED as claimed in claim 27 removes flickering method, wherein, this step that produces an absolute difference signal comprises:
(a) this work output signal or (b) and the signal of this work output signal equal value of (one) this work input signal and (two) relatively is to produce a numeric ratio than signal; And
According to this numeric ratio than signal, decision (one) (two) when subtracting each other, He Zhewei just, He Zhewei is negative.
29. LED as claimed in claim 28 removes flickering method, wherein, also comprises: a up-down counter is provided, counts up and down than signal according to this numeric ratio, its output is as the work output signal.
30. LED as claimed in claim 24 removes flickering method, wherein, also comprises: dynamically set this magnetic hysteresis critical value.
31. LED as claimed in claim 30 removes flickering method, wherein, this step of dynamically setting the magnetic hysteresis critical value comprises: according to cycle of this pulse width modulation signal this work input signal maybe, set this magnetic hysteresis critical value.
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| CN 201010237119 CN102340907B (en) | 2010-07-21 | 2010-07-21 | Light emitting diode (LED) controller having function of flicker removal, LED flicker removal circuit and related method |
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| CN 201010237119 CN102340907B (en) | 2010-07-21 | 2010-07-21 | Light emitting diode (LED) controller having function of flicker removal, LED flicker removal circuit and related method |
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| CN104767566A (en) * | 2014-01-07 | 2015-07-08 | 中兴通讯股份有限公司 | Dimming method and device for alleviating inter-frame flicker |
| CN109362155A (en) * | 2018-11-19 | 2019-02-19 | 李亚焕 | A kind of device for preventing LED from flashing |
| CN109488916A (en) * | 2018-11-19 | 2019-03-19 | 李亚焕 | A kind of LED of anti-flashing |
| CN109862657A (en) * | 2018-11-19 | 2019-06-07 | 李亚焕 | A kind of anti-Flash drives of LED |
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| US6349023B1 (en) * | 2000-02-24 | 2002-02-19 | Robotic Vision Systems, Inc. | Power control system for illumination array |
| CN101765288A (en) * | 2008-12-25 | 2010-06-30 | 罗姆股份有限公司 | Control circuit for light-emitting element |
| CN101766062A (en) * | 2006-02-13 | 2010-06-30 | 路创电子公司 | electronic ballast having adaptive frequency shifting |
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| US6349023B1 (en) * | 2000-02-24 | 2002-02-19 | Robotic Vision Systems, Inc. | Power control system for illumination array |
| CN101766062A (en) * | 2006-02-13 | 2010-06-30 | 路创电子公司 | electronic ballast having adaptive frequency shifting |
| CN101765288A (en) * | 2008-12-25 | 2010-06-30 | 罗姆股份有限公司 | Control circuit for light-emitting element |
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| CN104767566A (en) * | 2014-01-07 | 2015-07-08 | 中兴通讯股份有限公司 | Dimming method and device for alleviating inter-frame flicker |
| CN104767566B (en) * | 2014-01-07 | 2018-11-30 | 中兴通讯股份有限公司 | A kind of light-dimming method and device for alleviating interframe flashing |
| CN109362155A (en) * | 2018-11-19 | 2019-02-19 | 李亚焕 | A kind of device for preventing LED from flashing |
| CN109488916A (en) * | 2018-11-19 | 2019-03-19 | 李亚焕 | A kind of LED of anti-flashing |
| CN109862657A (en) * | 2018-11-19 | 2019-06-07 | 李亚焕 | A kind of anti-Flash drives of LED |
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| CN102340907B (en) | 2013-12-18 |
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