CN1658730A - Method for controlling brightness of LED by duty ratio - Google Patents
Method for controlling brightness of LED by duty ratio Download PDFInfo
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- CN1658730A CN1658730A CN2005100630685A CN200510063068A CN1658730A CN 1658730 A CN1658730 A CN 1658730A CN 2005100630685 A CN2005100630685 A CN 2005100630685A CN 200510063068 A CN200510063068 A CN 200510063068A CN 1658730 A CN1658730 A CN 1658730A
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- emitting diode
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- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000010586 diagram Methods 0.000 description 5
- 230000001276 controlling effect Effects 0.000 description 3
- 239000013256 coordination polymer Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000000007 visual effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
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- 230000002688 persistence Effects 0.000 description 1
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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
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Abstract
A method of controlling the light diode brightness by using the rate of engrossing and vacancy. Use the control signal to control the shine and extinguish of the light diode. The mentioned control signal makes the light diode in the shine state just in part time of one cycle of the mentioned control signal, while in the extinguishing state in other time of the mentioned one cycle. Besides control the brightness of the mentioned light diode through controlling the rate of engrossing and vacancy of the light diode. Thereinto the mentioned rate of engrossing and vacancy of the light diode is the proportion of the shine state time of the mentioned light diode in one cycle of the mentioned control signal in the mentioned cycle. Choicely, control the light diode by using the pulse with the frequency between 100 Hz and 1MHz, and control the brightness of the light diode through controlling the rate of engrossing and vacancy of the mentioned pulse. The advantages are multiple brightness for the single light diode and less element.
Description
Technical field
The present invention relates to the method for a kind of control light-emitting diode (LED) brightness, relate in particular to a kind of method of utilizing duty ratio control light-emitting diode luminance.
Background technology
General light-emitting diode has two states: Kai Heguan, the on and off of corresponding LED respectively.Fig. 1 represents that traditional being used to control the control signal waveform that light-emitting diode is lighted operation.Control signal constantly becomes high level at t 1 in the figure, and light-emitting diode is lighted; Until t2 constantly just becomes low level again, light-emitting diode extinguishes.Usually, lighting operation and extinguishing operation of light-emitting diode is macroscopic, and the chronomere that light-emitting diode is kept " bright " state or " going out " state normally is the order of magnitude with the second.In some actual track designs, the drive current of light-emitting diode or driving voltage are changeless, and the brightness when light-emitting diode is lighted so also is fixing immutable.Yet, under some occasions, require single light-emitting diode to have two or more states.For example, when the secondary light source, the brightness that people wish LED is adjustable to obtain optimum efficiency according to concrete ambient conditions.In addition, utilize traditional control method in the three-color LED indicator light, can only generate the very limited color of quantity.
Summary of the invention
The immutable problem of brightness provides a kind of method of controlling light-emitting diode luminance when therefore, the objective of the invention is to light at light-emitting diode above-mentioned.
Based on human eye " persistence of vision " effect to scenery, promptly can also on retina, keep the regular hour behind the Loss Of View, obtained design philosophy of the present invention: utilize the signal controlling light-emitting diode with appropriate frequency make its only the part-time in the one-period of this signal be in " bright " state and all the other times in this cycle are in " going out " state so that this light-emitting diode is in " bright " state at human eye always, and adjust its brightness by the control light-emitting diode is in " bright " state in a signal period time shared ratio in this signal period.
Based on above design philosophy, a kind of method of utilizing the brightness of duty ratio control light-emitting diode (LED) is provided, this method is utilized " bright " and " going out " of control signal control light-emitting diode, described control signal make light-emitting diode only the part-time in the one-period of described control signal be in " bright " state and all the other times in described one-period are in " going out " state, and recently control the brightness of described light-emitting diode by the duty of control light-emitting diode, the duty ratio of wherein said light-emitting diode is described light-emitting diode is in " bright " state in the one-period of described control signal time shared ratio in the described cycle.
Preferably, the frequency of described control signal is 100Hz～1MHz.
Preferably, described control signal is pulse, and the brightness that described duty by the control light-emitting diode is recently controlled described light-emitting diode comprises by controlling described duty of ratio controls the brightness of described light-emitting diode.
Preferably, the frequency of described pulse is 100Hz～1MHz.
According to the present invention, the device of a kind of control light-emitting diode (LED) brightness is provided, comprise control device, thereby the control signal that this control device produces EDM Generator of Adjustable Duty Ratio is controlled the brightness of described light-emitting diode with the duty ratio of control light-emitting diode, and the duty ratio of wherein said light-emitting diode is described light-emitting diode is in " bright " state in the one-period of described control signal time shared ratio in the described cycle.
Preferably, described control signal is pulse.
Preferably, the frequency of described control signal is 100Hz～1MHz.
The invention has the beneficial effects as follows: one, can make single light-emitting diode that the brightness of required a plurality of grades is provided, can make human eye perceives less than tangible scintillation by the suitable frequency of selecting control signal simultaneously; Two, can save corresponding components and parts effectively.
Description of drawings
Can be well understood to content of the present invention by accompanying drawing more in conjunction with detailed description to execution mode.Wherein:
Fig. 1 is according to prior art, generally be used to control the control signal waveform schematic diagram that LED lights operation;
Fig. 2 is according to control signal schematic diagram of the present invention, that utilize duty of ratio control light-emitting diode luminance;
Fig. 3 is the waveform schematic diagram after the segment pulse of control signal among Fig. 2 amplifies;
Fig. 4 is the circuit diagram that is used to produce pulse control signal according to one particular embodiment of the present invention; With
Fig. 5 is a kind of servicing unit schematic diagram that is used for the driven for emitting lights diode.
Embodiment
Fig. 2 shows one according to the control signal waveform that utilizes duty of ratio control light-emitting diode luminance of the present invention.From t1 constantly, control signal becomes pulse with a certain frequency change from low level, and LED lights.The frequency of this pulse is higher, is generally 100Hz～1MHz, like this from visual effect with imperceptible tangible flicker.To t2 constantly, control signal becomes low level from pulse, and LED extinguishes.
Waveform after the segment pulse that Fig. 3 shows control signal among Fig. 2 amplifies.In each period T, the time of high level is H, and the low level time is L, so duty of ratio can be expressed as H/ (H+L).When duty ratio was 0, waveform was a low level; When duty ratio was 1, waveform was a high level.When being in " bright " state at light-emitting diode, by regulating the brightness that this duty ratio just can be regulated LED: when duty ratio was 0, LED extinguished; When duty ratio was 1, LED reached the brightest state; When duty ratio changed between 0 and 1, the brightness of LED was also along with variation.
Fig. 4 shows the circuit that is used to produce pulse control signal according to one particular embodiment of the present invention.For example, in actual applications, need duty ratio have 16 grades adjustable, can design a kind of circuit as shown in Figure 4 for this reason.Counter among Fig. 4 serves as to produce the binary number Q (Q3Q2Q1Q0) that increases continuously at interval according to input clock signal CP with this clock cycle, becomes 0 again when Q is increased to predefined value D (D3D2D1D0), increases continuously since 0 again; So go round and begin again.Comparator among Fig. 4 compares by the value to two input A (A3A2A1A0) and B (B3B2B1B0), output 1 (high level) or 0 (low level).If A is less than B, then comparator output 1, otherwise exports 0.Q delivered in the comparator compare with predefined value B, if severals Q of counter output less than B, then comparator is exported 1 (high level), otherwise is output as 0 (low level).In the present embodiment, D is made as 15, promptly binary number 1111.By the value of configuration B, the pulse that can obtain having different duty.
Suppose to obtain duty ratio and be 0 waveform, just B can be made as 0, promptly binary number 0000.Like this, counter produces 0,1,2,3,4 successively ..., in the time of 15, comparator output (output) is 0 always, goes round and begins again then.Can know that by analysis the waveform duty cycle of comparator output (output) is 0;
Suppose to obtain duty ratio and be 1/16 waveform, just B can be made as 1, promptly binary number 0001.Like this, when counter produced 0, comparator output (output) was 1, and next counter produces 1,2,3,4 successively ..., in the time of 15, comparator output (output) is 0, goes round and begins again then.Can know that by analysis the waveform duty cycle of comparator output (output) is 1/16 just;
Suppose to obtain duty ratio and be 2/16 waveform, just B can be made as 2, promptly binary number 0010.Like this, when counter produced 0,1 successively, comparator output (output) was 1, and next counter produces 2,3,4 ..., in the time of 15, comparator output (output) is 0.Go round and begin again then.Can know that by analysis the waveform duty cycle of comparator output (output) is 2/16 just;
And the like, B is made as 3, can obtain duty ratio and be 3/16 impulse waveform; B is made as 4, can obtains duty ratio and be 4/16 impulse waveform; B is made as 15, can obtains duty ratio and be 15/16 impulse waveform;
Under the identical situation of other condition, utilize duty ratio to be respectively 0,1/16,2/16,3/16 ..., light-emitting diode is controlled in 15/16 pulse just can obtain 16 kinds of brightness.
In addition, in this particular example, the pulse frequency of output is 1/16 of a clock signal C P frequency, supposes to expect the output pulse of 100KHz, and the CP frequency of input just should be 1.6MHz; Suppose to expect the output pulse of 1MHz, the CP frequency of input just should be 16MHz.
The light-emitting diode that has can directly be driven by control signal; Under the situation that light-emitting diode can not be driven by control signal, can utilize servicing unit to drive.Servicing unit can be that for example, circuit as shown in Figure 5 wherein shows a kind of servicing unit that comprises triode and resistance, according to specific requirement, the bias voltage of triode etc. can be set.
The method according to this invention can be used for various occasions.
For example, control signal shown in Figure 2 can be used for the white light LEDs in a kind of mobile phone photograph secondary light source.For example, the frequency of control impuls is made as 1MHz, the LED duty ratio under the initial condition is made as 100%.When taking pictures,, can suitably regulate the LED duty of ratio to obtain the suitable photo of brightness according to the power of ambient lighting.If ambient lighting is brighter, for example, pulse duty factor can be reduced to 50% or lower.
In a kind of three-color LED, for example, this three-color LED can be used for producing the seven-color LED that changes with music.The pulse frequency of every kind of monochromatic LED control signal is made as 1MHz, and their duty ratio all is set to regulate separately.Consider actual visual effect, for example, the pulse duty factor of every kind of monochromatic LED can be respectively certain value in 0,25%, 50%, 75% and 100%, just can be combined into more colors like this on same three-color LED basis.As required, duty of ratio can be got other value.
Claims (10)
1. the method for control light-emitting diode (LED) brightness, utilize " bright " and " going out " of control signal control light-emitting diode, it is characterized in that, described control signal make light-emitting diode only the part-time in the one-period of described control signal be in " bright " state and all the other times in described one-period are in " going out " state, and recently control the brightness of described light-emitting diode by the duty of control light-emitting diode, the duty ratio of wherein said light-emitting diode is described light-emitting diode is in " bright " state in the one-period of described control signal time shared ratio in the described cycle.
2. method according to claim 1 is characterized in that, the frequency of described control signal is 100Hz～1MHz.
3. method according to claim 1, it is characterized in that, described control signal is pulse, and the brightness that described duty by the control light-emitting diode is recently controlled described light-emitting diode comprises by controlling described duty of ratio controls the brightness of described light-emitting diode.
4. method according to claim 3 is characterized in that, the frequency of described pulse is 100Hz～1MHz.
5. according to the described method of arbitrary claim among the claim 1-4, it is characterized in that described light-emitting diode is driven by described control signal.
6. according to the described method of arbitrary claim among the claim 1-4, it is characterized in that described light-emitting diode is driven by servicing unit.
7. the device of control light-emitting diode (LED) brightness, it is characterized in that, comprise control device, thereby the control signal that this control device produces EDM Generator of Adjustable Duty Ratio is controlled the brightness of described light-emitting diode with the duty ratio of control light-emitting diode, and the duty ratio of wherein said light-emitting diode is described light-emitting diode is in " bright " state in the one-period of described control signal time shared ratio in the described cycle.
8. device according to claim 7 is characterized in that described control signal is pulse.
9. according to claim 7 or 8 described devices, it is characterized in that the frequency of described control signal is 100Hz～1MHz.
10. according to claim 7 or 8 described devices, it is characterized in that, described control device comprises counter and comparator, the output of described counter is connected to an input of described comparator, and the value of the described output of described counter is transfused in the described comparator with the predetermined value with another input of described comparator and compares.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2005100630685A CN1658730A (en) | 2005-04-05 | 2005-04-05 | Method for controlling brightness of LED by duty ratio |
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| CN2005100630685A CN1658730A (en) | 2005-04-05 | 2005-04-05 | Method for controlling brightness of LED by duty ratio |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007124666A1 (en) * | 2006-04-28 | 2007-11-08 | Hong Kong Applied Science and Technology Research Institute Co. Ltd | Efficient lighting |
| US7586271B2 (en) | 2006-04-28 | 2009-09-08 | Hong Kong Applied Science and Technology Research Institute Co. Ltd | Efficient lighting |
| CN101052254B (en) * | 2006-04-07 | 2010-05-12 | 杨毅 | Method for driving LED emitting |
| CN101169756B (en) * | 2006-10-27 | 2010-06-16 | 武汉楚天激光（集团）股份有限公司 | Use LED half-brightness as the display method of the background running status of the project |
| CN101765276A (en) * | 2010-02-12 | 2010-06-30 | 上海新凯元照明科技有限公司 | Illumination system and illumination control method thereof |
| CN102159010A (en) * | 2011-03-28 | 2011-08-17 | 上海华为技术有限公司 | Device and method for controlling indicator lights |
| CN101620826B (en) * | 2009-08-17 | 2011-08-31 | 南京信息职业技术学院 | Driving method and circuit for large-screen LED true color display screen |
| CN102378454A (en) * | 2011-12-05 | 2012-03-14 | 合肥美的荣事达电冰箱有限公司 | Breath light control circuit |
| CN103957627A (en) * | 2014-04-21 | 2014-07-30 | 四川长虹电器股份有限公司 | Indicating lamp brightness control method |
-
2005
- 2005-04-05 CN CN2005100630685A patent/CN1658730A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101052254B (en) * | 2006-04-07 | 2010-05-12 | 杨毅 | Method for driving LED emitting |
| WO2007124666A1 (en) * | 2006-04-28 | 2007-11-08 | Hong Kong Applied Science and Technology Research Institute Co. Ltd | Efficient lighting |
| US7294978B1 (en) | 2006-04-28 | 2007-11-13 | Hong Kong Applied Science And Technology Research Institute Co. Ltd. | Efficient lighting |
| US7586271B2 (en) | 2006-04-28 | 2009-09-08 | Hong Kong Applied Science and Technology Research Institute Co. Ltd | Efficient lighting |
| CN101169756B (en) * | 2006-10-27 | 2010-06-16 | 武汉楚天激光（集团）股份有限公司 | Use LED half-brightness as the display method of the background running status of the project |
| CN101620826B (en) * | 2009-08-17 | 2011-08-31 | 南京信息职业技术学院 | Driving method and circuit for large-screen LED true color display screen |
| CN101765276A (en) * | 2010-02-12 | 2010-06-30 | 上海新凯元照明科技有限公司 | Illumination system and illumination control method thereof |
| CN102159010A (en) * | 2011-03-28 | 2011-08-17 | 上海华为技术有限公司 | Device and method for controlling indicator lights |
| CN102378454A (en) * | 2011-12-05 | 2012-03-14 | 合肥美的荣事达电冰箱有限公司 | Breath light control circuit |
| CN102378454B (en) * | 2011-12-05 | 2014-10-01 | 合肥美的电冰箱有限公司 | A breathing light control circuit |
| CN103957627A (en) * | 2014-04-21 | 2014-07-30 | 四川长虹电器股份有限公司 | Indicating lamp brightness control method |
| CN103957627B (en) * | 2014-04-21 | 2016-07-06 | 四川长虹电器股份有限公司 | The method controlling display lamp brightness |
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Open date: 20050824 |