CN1909754A - Illuminating source apparatus and light-adjustable light-emitting diode control circuit - Google Patents
Illuminating source apparatus and light-adjustable light-emitting diode control circuit Download PDFInfo
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- CN1909754A CN1909754A CNA2005100898237A CN200510089823A CN1909754A CN 1909754 A CN1909754 A CN 1909754A CN A2005100898237 A CNA2005100898237 A CN A2005100898237A CN 200510089823 A CN200510089823 A CN 200510089823A CN 1909754 A CN1909754 A CN 1909754A
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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
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Abstract
The invention relates to a light source and relative light-emitting diode control circuit for adjusting light. Said control circuit can be used to control the brightness of several groups of light-emitting diodes in liquid crystal display. Said control circuit comprises a control impulse generator and several light-emitting diode direct-current power source suppliers; said generator is used to receive one brightness adjusting signal, to generate several groups of brightness control impulse signals with same frequency and different phases; the working period of brightness control impulse signal is changed in one preset range based on the brightness adjustment signal; the light-emitting diode direct-current current supplier is coupled to the control impulse generator, to drive relative light-emitting diode based on the brightness control impulse signal.
Description
Technical field
The invention relates to a kind of adjusting control circuit, relate to a kind of being used for, and particularly be used for the beam density adjusting control circuit of most light-emitting diodes of an above different colours as light source relevant for a kind of with the beam density adjusting control circuit of the individual light-emitting diodes of majority more than as light source.
Background technology
Adopt light-emitting diode (LED) as light emitting source, can realize the system requirements of LCD backlight or general lighting with simple direct current driven circuit.Because the relation of characteristic, the brightness of light-emitting diode is not linear variation with driving direct current, and color also can be different with drive current variations, this produces very big obstacle for the system of light-emitting diode as LCD backlight or general lighting in the application that directly utilizes the mode light modulation of adjusting light-emitting diode driving direct current.
For overcoming the shortcoming of utilizing the electric current light modulation, the present practice is not to change the mode light modulation that light-emitting diode drives the current amplitude size, but under the fixed-size situation of led current amplitude, carry out light modulation in the mode that changes the led current beam density under the preset working frequency, so that can make light-emitting diode in the dimming scope of maximum, present needed stable color.
See also Figure 1 and Figure 2, Fig. 1 is known with DC current source driven for emitting lights diode and with the schematic diagram of beam density brightness adjustment control output current, and Fig. 2 then is that the brilliance control pulse wave signal of Fig. 1 circuit and light-emitting diode drive dc current signal and concern schematic diagram.In Fig. 1, control light-emitting diode 120 bright or dark brilliance control pulse wave signal CNTL send into light-emitting diode direct current supply 110, with the light-emitting diode driving current signal Id of control light-emitting diode direct current supply 110 output driven for emitting lights diodes 120, this electric current is a fixed current according to brightness demand predetermined current size.In Fig. 2, (a) and (b), (c) are three kinds of output waveform figures that are subjected to the light-emitting diode driving current signal Id of distinct pulse widths control, Fig. 2 (a) is that a brightness has only complete 20% situation when bright, Fig. 2 (b) is the example that a brightness has only complete 60% when bright, and Fig. 2 (c) then is that a brightness is the example of complete 100% when bright.
For avoiding because light-emitting diode the time secretly cause interference on the human eye vision when bright, the frequency of this brilliance control pulse wave signal CNTL can not be too low usually, generally all more than 200Hz.Use enough high-frequency brilliance control pulse wave signal CNTL,, allow human eye only experience the variation of light-emitting diode luminance and can not glimmer according to the effect that human eye vision persists.
Owing to frequency and work period of the brilliance control pulse wave signal CNTL of aforementioned use is along with required brightness is set, therefore in case carry out light modulation, the frequency of brilliance control pulse wave signal CNTL in the application of LCD backlight, can meet with the video signal shows signal in vertical, horizontal time-base produce the problem that difference frequency disturbs.Because the backlight and relation video signal different frequency causes so-called " fanning effect ", and on picture, form the ripples line that disturbs.In addition, the startup of light-emitting diode direct current supply and the burden of closing the power supply unit that also can cause supply light-emitting diode direct current supply power demand, and producing the ripple with frequency with brilliance control pulse wave signal CNTL at power supply unit, this ripple also can influence the video signal shows signal once more and cause film flicker.These are because the interference that caused of beam density light modulation, are using the multiple more optical diode can be more serious along with the increase of light-emitting diode operand power as the occasion of light source.
For avoiding vertical, horizontal time-base in brilliance control pulse wave signal CNTL and the video signal shows signal to produce the problem that difference frequency disturbs, it is with brilliance control pulse wave signal CNTL and horizontal time-base synchronizing and frequency doubling or frequency elimination that a kind of practice is arranged.In addition, also the frequency of brilliance control pulse wave signal CNTL can be improved, to reduce power supply unit is caused the formed interference of ripple, but driving under the gesture that LCD maximizes gradually, light-emitting diode is more with many more and power that it consumed is also increasing, and but the vision noise is required under the more and more stricter situation, low noise, light modulation on a large scale also become increasingly difficult in actual production.
Summary of the invention
In view of this, the purpose of this invention is to provide a kind of low vision noise beam density adjusting control circuit that is applied to more than most light-emitting diodes as light source, particularly by the light source that light-emitting diode constituted of different colours.And by the phase place of controlling each different light-emitting diode luminances control pulse wave signal, to improve the vision noise interference that the beam density light modulation is produced.
The invention provides a kind of LED control circuit of low vision noise beam density, during LCD or other need in the display of light source in this way applicable to control example as the luminosity of the multi-group light-emitting diode of light source.LED control circuit of the present invention comprises control pulse wave generating unit and optical diode direct current supply unit.Wherein, the control pulse wave generating unit is in order to receive a brightness adjusting signal, and produce identical but the brilliance control pulse wave signal that phase place is different of many class frequencys according to this brightness adjusting signal, and the work period of this brilliance control pulse wave signal system change in a preset range according to brightness adjusting signal.Light-emitting diode direct current supply then couples the control pulse wave generating unit, drives corresponding light-emitting diode with foundation brilliance control pulse wave signal.
In one embodiment, the brilliance control pulse wave generating unit of this LED control circuit has comprised triangular wave generator and comparator unit.Wherein, the triangular wave generator can produce the identical but triangular wave of out of phase of most class frequencys.And each comparator in the comparator unit can be with brightness regulated signal and these same frequencys but the triangular wave of out of phase make comparisons, aforesaid with frequently, with the work period but the brilliance control pulse wave signal of out of phase to produce.
From another viewpoint, the present invention provides a kind of light supply apparatus in addition, applicable to LCD.Light supply apparatus of the present invention comprises brilliance control pulse wave generating unit, most light-emitting diode direct current supplies and most light-emitting diodes.Wherein, the brilliance control pulse wave generating unit is in order to receiving a brightness regulated signal, and according to brightness regulated signal produce many group same frequencys, with the work period but the brilliance control pulse wave signal of out of phase.Light-emitting diode direct current supply then couples the brilliance control pulse wave generating unit, drives corresponding light-emitting diode with foundation brilliance control pulse wave signal.
In preferred embodiment, the brilliance control pulse wave generating unit of this low vision noise beam density adjusting control circuit is to be realized by microprocessor and other digit circuit of a digital type.
In an embodiment of the present invention, the work period of above-mentioned brilliance control pulse wave signal is to change in a preset range according to brightness regulated signal.
By in the above-mentioned explanation as can be known, use the LED control circuit of a kind of low vision noise beam density provided by the present invention, then can be by the phase places of much more staggered group brilliance control pulse wave signals, improve the vision noise that the beam density light modulation produced and disturb.
For above-mentioned and other purposes, feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and cooperate appended graphicly, be described in detail below.
Description of drawings
Fig. 1 is a kind of known beam density adjusting control circuit schematic diagram.
Fig. 2 is that the brilliance control pulse wave signal and the light-emitting diode driving current signal of Fig. 1 circuit concerns schematic diagram.
Fig. 3 is a kind of low vision noise beam density adjusting control circuit block schematic diagram of the preferred embodiment according to the present invention.
Fig. 4 is a kind of brilliance control pulse wave generating unit circuit diagram of the preferred embodiment according to the present invention.
Fig. 5 A and Fig. 5 B are the brilliance control pulse wave signal schematic diagrames that the brilliance control pulse wave generating unit of Fig. 4 produces.
Fig. 6 is that a kind of digital type brilliance control pulse wave generating unit circuit diagram of the preferred embodiment according to the present invention is implemented.
110,321,322,32N: light-emitting diode direct current supply
120,330,331,332,33N: light-emitting diode
300: low vision noise beam density adjusting control circuit
310,400: the brilliance control pulse wave generating unit
410: the triangular wave generator
420,401,402,40N: comparator
610: digital type brilliance control pulse wave generating unit
620: microprocessor
630: high frequency time pulse generator
640: memory body
Embodiment
Please refer to shown in Figure 3, it is a kind of low vision noise beam density adjusting control circuit block schematic diagram of the preferred embodiment according to the present invention, and this low vision noise beam density adjusting control circuit 300 is applicable to the luminosity of the multi-group light-emitting diode 330 in the control LCD.
As shown in the figure, this low vision noise beam density adjusting control circuit 300 comprises: brilliance control pulse wave (pulse) generation unit 310, light-emitting diode direct current supply unit 320 and light-emitting diode 330.Wherein, brilliance control pulse wave generating unit 310 is in order to receiving brightness regulated signal BTNS, and according to brightness regulated signal BTNS produce many group brilliance control pulse wave signal CNTL1, CNTL2 ..., CNTLN.
Wherein, each the direct current supply 321,322 in the light-emitting diode direct current supply unit 320 ..., 32N supply respectively not on the same group light-emitting diode 331,332 ..., 33N not on the same group electric current I d1, Id2 ..., IdN.These drive currents Id1, Id2 ..., IdN light-emitting diode 331,332 ..., when the color of 33N is identical, can be the predetermined value of setting the same current size according to the brightness demand.When light-emitting diode 331,332 ..., the color of 33N not simultaneously, for example red, indigo plant, green three looks also can be according to the color behind brightness and the mixed light, white for example, and set the unequal current value of size of current each other.
These brilliance control pulse wave signal CNTL1, CNTL2 that produce according to brilliance control pulse wave generating unit 310 ..., CNTLN, each direct current supply 321,322 in can respectively corresponding control light-emitting diode direct current supply unit 320 ..., 32N, with determine each group light-emitting diode 331,332 ..., conducting electric current I d1, the Id2 of 33N ..., conducting or the cut-off state of IdN.
In the present invention, in order to improve the vision noise interference that the beam density light modulation is produced, so with this many group brilliance control pulse wave signal CNTL1, CNTL2 ..., the phase cross-over control of CNTLN, with reduce not on the same group light-emitting diode 331,332 ..., have only on the 33N time point in office wherein one group to change because of light modulation and to end or the situation of conducting.
Because light-emitting diode is not to change together because of light modulation simultaneously to end or conducting state, therefore can significantly reduce by light-emitting diode and change the power noise that conducting state produced.These power noises light-emitting diode during as the LCD light source with the video signal shows signal in vertical, horizontal time-base produce difference frequency and disturb, cause so-called " fanning effect ", and on picture, form the ripples line that disturbs.
Please refer to shown in Figure 4ly, this is a kind of brilliance control pulse wave generating unit circuit diagram of the preferred embodiment according to the present invention, and this brilliance control pulse wave generating unit 400 has comprised triangular wave generator 410 and comparator unit 420.Wherein, triangular wave generator 410 produce one group of and out of phase identical with upper frequency triangular wave Tri1, Tri2 ..., TriN, and each comparator 401,402 in the comparator unit 420 ..., 40N with triangular wave Tri1, the Tri2 of brightness regulated signal BTNS and these same frequency outs of phase ..., TriN makes comparisons, produce aforesaid with frequently, with the work period but brilliance control pulse wave signal CNTL1, the CNTL2 of out of phase ..., CNTLN.
For more clearly demonstrating spirit of the present invention, therefore when present embodiment control be three groups of light-emitting diodes the time, the timing diagram of its each control signal can be shown in Fig. 5 A and Fig. 5 B, be that to work as the brightness of being controlled be complete 2/3 when bright of light-emitting diode shown in Fig. 5 A wherein, i.e. 66.67% o'clock sequential chart, Fig. 5 B illustrates then that to work as the brightness of being controlled be complete 1/3 when bright of light-emitting diode, i.e. 33.33% o'clock sequential chart.
When the phase difference of three groups of triangular signal Tri1, Tri2 in the present embodiment and Tri3 differs 60 °, also can produce brilliance control pulse wave signal CNTL1, CNTL2 and the CNTL3 of out of phase after relatively with brightness regulated signal BTNS.With such signal controlling light-emitting diode, can make three groups of light-emitting diodes not change conducting or cut-off state simultaneously, make and have only one group of light-emitting diode to change conducting or cut-off state on the whole power line on the time in office forever.Compared to the control mode of three groups of conduction status of conversion simultaneously, the present invention can drop to 1/3 with the ripple on the power line.
Though the above-mentioned control mode that three groups of light-emitting diodes only are provided can be according to spirit of the present invention yet have the knack of this skill person, and derive arbitrarily to more groups LED control circuit.
When the light-emitting diode group number constantly increases, implement the present invention with digit circuit and can control more multi-group light-emitting diode more accurately.Fig. 6 promptly is one and utilizes the microprocessor (MCU) of numerical digit and the embodiment that other digit circuit constitutes.
In the embodiment of Fig. 6, the meter that digital type brilliance control pulse wave generating unit 610 has comprised microprocessor 620, high frequency time pulse generator 630 and has been used for storing all design parameters and formula is recalled body 640.High frequency time pulse generator 630 is except providing the required operation clock pulse CLK of microprocessor 620, microprocessor utilizes this high frequency time pulse to cooperate its inner divider and counter (not illustrating), and according to the brightness regulated signal BTNS of input can produce brightness pulse wave signal CNTL1, CNTL2 with predeterminated frequency and work period ..., CMTLN.And be stored in all design parameters in the memory body (memory device) 640 and formula just with decide microprocessor 620 calculate these many groups of brightness pulse wave signal CNTL1, the CNTL2 of producing ..., its operating frequency of CNTLN, and each brightness pulse wave signal phase relation each other.
Because brightness pulse wave signal CNTL1, CNTL2 ..., work period of CMTLN, be brightness regulated signal BTNS, and the clock pulse CLK counting that utilizes digit counter that high frequency time pulse generator 630 is produced according to input.Therefore, each group brightness pulse wave signal CNTL1, CNTL2 ..., between the CNTLN almost without any error (Offset).Look back the embodiment of Fig. 4 because each comparator 401,402 ..., the error between 40N and inequality, and these error voltages have its temperature coefficient independently separately.Therefore, the such numerical digit signal producing method of Fig. 6 is having splendid stable operation degree under the embodiment of Fig. 4.Therefore be well suited for the control circuit of more groups of complexity and the accurate light modulation of needs.Particularly the white light when light-emitting diode is the occasion that is mixed by various different color light light-emitting diodes.Because in such system, once the luminous work period ratio of different colours light-emitting diode for example changes: CNTL1 the work period ≠ CNTL2 work period ≠ ..., ≠ work period CNTLN, the result of its mixed light will change, and its color relation can become thereupon.So, these light-emitting diodes just can change as required and color arbitrarily, memory body in Fig. 6 embodiment then can store the various different colours of decision as required, the content of brightness produce each group brightness pulse wave signal CNTL1, CNTL2 ..., CNTLN.
In Fig. 6 embodiment, for the vision noise that system is produced as the LCD light source applications time further is reduced, can also utilize the clock signal DCLK that produces by LCD, when the input signal as high frequency time pulse generator 630 produces high frequency time pulse CLK, to avoid because " difference frequency disturbs " the ripples line that causes appears on the display.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; any personnel that have the knack of this technology; without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is when looking being as the criterion that accompanying Claim defines.
Claims (11)
1. the LED control circuit of a tunable optical is applicable to that most light-emitting diodes of control is characterized in that it comprises:
A most direct current supply are in order to supply a direct current electric current respectively to corresponding light-emitting diode; And
One control pulse wave generating unit, in order to produce most fixed-frequency and identical control pulse wave signal according to a brightness regulated signal, and work periods system of those control pulse wave signals changes in a preset range according to this brightness regulated signal but phase place difference each other, to control the electric current supply status of those direct current feeding units respectively.
2. the LED control circuit of tunable optical according to claim 1, it is characterized in that wherein each those direct current supply can be respectively according to corresponding control pulse wave signal supply of current and stop supplies current both one of them.
3. a light supply apparatus is applicable to a LCD, it is characterized in that it comprises:
A most light-emitting diode;
A most direct current supply are in order to supply a drive current to corresponding light-emitting diode respectively; And
One control pulse wave generating unit, in order to produce most fixed-frequency and identical control pulse wave signal according to a brightness regulated signal, and work periods system of those control pulse wave signals changes in a preset range according to this brightness regulated signal but phase place difference each other, to control the electric current supply status of those direct current feeding units respectively.
4. light supply apparatus according to claim 3, it is characterized in that each those direct current supply wherein can be respectively according to corresponding control pulse wave signal supply of current and stop supplies current both one of them.
5. light supply apparatus according to claim 3 is characterized in that light-emitting diode wherein comprises the light-emitting diode of at least two kinds of different colours.
6. light supply apparatus according to claim 5, wherein the light-emitting diode of those different colours is that direct current by different size of current is driven.
7. light supply apparatus according to claim 3, the frequency of wherein controlling pulse wave signal are that the clock signal according to this LCD determines.
8. one kind can provide the light sources of different colors device, is used for display, it is characterized in that it comprises:
A most different color LEDs;
A most current supply are in order to supply a drive current to corresponding different color LEDs respectively; And
One controls pulse wave generating unit, control pulse wave signals in order to produce most, and work periods of those control pulse wave signals ties up to variation respectively in the preset range, to control the electric current supply status of those current supply units respectively.
9. light supply apparatus according to claim 8, the work period that it is characterized in that control pulse wave signal wherein is to determine according to the content that a memory body stores.
10. light supply apparatus according to claim 8, the frequency that it is characterized in that control pulse wave signal wherein are that the clock signal according to this display determines.
11. light supply apparatus according to claim 8 is characterized in that the phase place of control pulse wave signal wherein is to differ from one another.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2005100898237A CN1909754B (en) | 2005-08-05 | 2005-08-05 | Illuminating source apparatus and light-adjustable light-emitting diode control circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2005100898237A CN1909754B (en) | 2005-08-05 | 2005-08-05 | Illuminating source apparatus and light-adjustable light-emitting diode control circuit |
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| CN1909754A true CN1909754A (en) | 2007-02-07 |
| CN1909754B CN1909754B (en) | 2011-05-18 |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101409058A (en) * | 2007-10-11 | 2009-04-15 | 乐金显示有限公司 | LCD device including backlight unit and drive method thereof |
| CN101727805B (en) * | 2008-10-14 | 2012-02-01 | 华映视讯（吴江）有限公司 | Drive circuit of light source |
| CN101364380B (en) * | 2007-08-08 | 2012-03-21 | 奇美电子股份有限公司 | Back light module, liquid crystal display and color temperature control method |
| CN102468747A (en) * | 2010-11-19 | 2012-05-23 | 无锡芯朋微电子有限公司 | Charge pump control circuit |
| CN102496350A (en) * | 2011-11-04 | 2012-06-13 | 友达光电股份有限公司 | Light source system with staggered driving mechanism |
| CN101568218B (en) * | 2008-04-24 | 2012-10-03 | 台达电子工业股份有限公司 | Stabilizer |
| CN101589539B (en) * | 2007-02-21 | 2012-10-17 | 夏普株式会社 | Load driving circuit, integrated circuit, dc-dc converter and load driving method |
| CN102889500A (en) * | 2011-07-19 | 2013-01-23 | 硕颉科技股份有限公司 | Backlight module and liquid crystal display using same |
| CN103841704A (en) * | 2012-11-23 | 2014-06-04 | 海洋王（东莞）照明科技有限公司 | Led lamp control circuit |
| US9336726B2 (en) | 2007-10-11 | 2016-05-10 | Lg Display Co., Ltd. | Liquid crystal display device including backlight unit and method of driving the same |
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2005
- 2005-08-05 CN CN2005100898237A patent/CN1909754B/en not_active Expired - Fee Related
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101589539B (en) * | 2007-02-21 | 2012-10-17 | 夏普株式会社 | Load driving circuit, integrated circuit, dc-dc converter and load driving method |
| CN101364380B (en) * | 2007-08-08 | 2012-03-21 | 奇美电子股份有限公司 | Back light module, liquid crystal display and color temperature control method |
| CN101409058A (en) * | 2007-10-11 | 2009-04-15 | 乐金显示有限公司 | LCD device including backlight unit and drive method thereof |
| CN101409058B (en) * | 2007-10-11 | 2012-11-14 | 乐金显示有限公司 | LCD device including backlight unit and drive method thereof |
| US9336726B2 (en) | 2007-10-11 | 2016-05-10 | Lg Display Co., Ltd. | Liquid crystal display device including backlight unit and method of driving the same |
| CN101568218B (en) * | 2008-04-24 | 2012-10-03 | 台达电子工业股份有限公司 | Stabilizer |
| CN101727805B (en) * | 2008-10-14 | 2012-02-01 | 华映视讯（吴江）有限公司 | Drive circuit of light source |
| CN102468747A (en) * | 2010-11-19 | 2012-05-23 | 无锡芯朋微电子有限公司 | Charge pump control circuit |
| CN102889500A (en) * | 2011-07-19 | 2013-01-23 | 硕颉科技股份有限公司 | Backlight module and liquid crystal display using same |
| CN102496350A (en) * | 2011-11-04 | 2012-06-13 | 友达光电股份有限公司 | Light source system with staggered driving mechanism |
| CN102496350B (en) * | 2011-11-04 | 2014-11-05 | 友达光电股份有限公司 | Light source system with staggered driving mechanism |
| CN103841704A (en) * | 2012-11-23 | 2014-06-04 | 海洋王（东莞）照明科技有限公司 | Led lamp control circuit |
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