CN107995744A - Color error ratio for LED illumination eliminates circuit - Google Patents

Color error ratio for LED illumination eliminates circuit Download PDF

Info

Publication number
CN107995744A
CN107995744A CN201711427781.2A CN201711427781A CN107995744A CN 107995744 A CN107995744 A CN 107995744A CN 201711427781 A CN201711427781 A CN 201711427781A CN 107995744 A CN107995744 A CN 107995744A
Authority
CN
China
Prior art keywords
circuit
signal
led
electrically connected
output terminal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201711427781.2A
Other languages
Chinese (zh)
Inventor
王宇
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shenzhen Lianda Qi Technology Co Ltd
Original Assignee
Shenzhen Lianda Qi Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shenzhen Lianda Qi Technology Co Ltd filed Critical Shenzhen Lianda Qi Technology Co Ltd
Priority to CN201711427781.2A priority Critical patent/CN107995744A/en
Publication of CN107995744A publication Critical patent/CN107995744A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • 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
    • Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)

Abstract

The present invention provides a kind of color error ratio for LED illumination and eliminates circuit, including reference voltage generator, error amplifier, saw-toothed wave generator, PWM comparators, the first compensation circuit, field-effect tube, processor；The drain electrode of field-effect tube is electrically connected a regulated power supply, and source electrode is electrically connected a LED luminescence units；PWM comparators generate the first square-wave signal to relative error voltage signal and triangular signal；First compensation circuit has the second square-wave signal for setting duty cycle with the first square-wave signal to produce with frequency, the output terminal of PWM comparators is connected to by a logical AND or logic or circuit, modulation generation third party's ripple signal, the break-make of field-effect tube is controlled, to realize the brightness regulation to LED light.The present invention solves RGB three-color LED brightness disproportionation phenomenons by the way of PWM compensation, and extra compensation resistance is not required in this mode, saves component cost and pcb costs, in addition reduces consumption and is compensating ohmically power consumption, it is obvious to may be such that overall power declines.

Description

Color error ratio for LED illumination eliminates circuit
Technical field
The present invention relates to field of LED illumination, and circuit is eliminated in particular to a kind of color error ratio for LED illumination.
Background technology
In RGB color LED applications at present, since RGB three-color LED threshold voltages are there are notable difference, so in equal electricity Can be there are brightness disproportionation phenomenon under pressure driving, such as R colors LED can be substantially partially bright, substantially partially red when causing to have R color contamination colors.
With reference to Fig. 1, currently used solution is that the different resistance of resistance value is connected on the LED of different color to compensate Threshold voltage deviation, prevents colour mixture.There is the weakness such as increase cost (including resistance and pcb areas), increase power consumption in this scheme.
The content of the invention
, can be in integrated circuit present invention aims at providing a kind of color error ratio for LED illumination to eliminate circuit Portion solves RGB three-color LED brightness disproportionation phenomenons by the way of PWM compensation, and realizes the fine setting of LED luminosity, widens The compensation range of basic PWM compensation schemes, this mode are not required extra compensation resistance, save component cost and pcb into This, in addition reduces consumption and is compensating ohmically power consumption, it is obvious to may be such that overall power declines.
To reach above-mentioned purpose, the present invention refers to that a kind of color error ratio for LED illumination eliminates circuit, and each LED shines It is bright to include three LED luminescence units, to realize RGB three-colour light-emittings respectively under the driving of same output voltage signal, its It is characterized in that, the color error ratio eliminates circuit connected in series between output voltage signal and LED luminescence units, including reference voltage Maker, error amplifier, saw-toothed wave generator, PWM comparators, the first compensation circuit, field-effect tube, processor；
The drain electrode of the field-effect tube is electrically connected a regulated power supply, and source electrode is electrically connected a LED luminescence units；
The reference voltage generator is generating a reference voltage signal；
The error amplifier includes a first input end, one second input terminal and an output terminal, wherein, first input end The output terminal of reference voltage generator is electrically connected to, the second input terminal is electrically connected to output voltage, the voltage letter of output terminal generation Number it is defined as error voltage signal；
The saw-toothed wave generator is generating a triangular signal；
The PWM comparators include two input terminals and an output terminal, wherein, two input terminals are respectively electrically connected to saw The output terminal of tooth wave producer, the output terminal of error amplifier, to relative error voltage signal and triangular signal, generation the One square-wave signal, by the output terminal of the first square wave signal transmission of generation to PWM comparators；
First compensation circuit includes the PWM screened circuits and a register being electrically connected to each other, and PWM screened circuits are used To produce second square-wave signal with setting duty cycle with the first square-wave signal with frequency；
The processor is electrically connected to the first compensation circuit, and the second square wave is believed with realizing by adjusting the configuration of register The modulation of number duty cycle；
The output terminal of first compensation circuit is connected to the defeated of PWM comparators by a logical AND or logic or circuit Outlet, to modulate generation third party's ripple signal, third party's ripple signal is transferred to the grid of field-effect tube, is imitated to controlling filed Should pipe break-make, to realize to the brightness regulation of LED light.
By above technical scheme, compared with existing, its significant beneficial effect is that it is possible in integrated circuit Internal to solve RGB three-color LED brightness disproportionation phenomenons by the way of PWM compensation, extra compensation resistance is not required in this mode, section Component cost and pcb costs are saved, in addition reduces consumption and is compensating ohmically power consumption, it is bright to may be such that overall power declines It is aobvious.
It should be appreciated that as long as aforementioned concepts and all combinations additionally conceived that describe in greater detail below are at this Sample design it is not conflicting in the case of can be viewed as the disclosure subject matter a part.In addition, required guarantor All combinations of the theme of shield are considered as a part for the subject matter of the disclosure.
Can be more fully appreciated from the following description with reference to attached drawing present invention teach that foregoing and other aspect, reality Apply example and feature.The feature and/or beneficial effect of other additional aspects such as illustrative embodiments of the present invention will be below Description in it is obvious, or learnt in practice by the embodiment instructed according to the present invention.
Brief description of the drawings
Attached drawing is not intended to drawn to scale.In the accompanying drawings, each identical or approximately uniform group shown in each figure It can be indicated by the same numeral into part.For clarity, in each figure, it is not that each part is labeled. Now, by example and the embodiment of various aspects of the invention will be described in reference to the drawings, wherein：
Fig. 1 is the structure diagram of conventional series resistance scheme.
Fig. 2 is the structure diagram of conventional PWM compensation schemes.
Fig. 3 be increase the first compensation circuit after PWM compensation schemes structure diagram.
Fig. 4 be increase the second compensation circuit after PWM compensation schemes structure diagram.
Embodiment
In order to know more about the technology contents of the present invention, especially exemplified by specific embodiment and institute's accompanying drawings are coordinated to be described as follows.
Each side with reference to the accompanying drawings to describe the present invention in the disclosure, shown in the drawings of the embodiment of many explanations. It is not intended to cover all aspects of the invention for embodiment of the disclosure.It should be appreciated that a variety of designs presented hereinbefore and reality Apply example, and those designs described in more detail below and embodiment can in many ways in any one come it is real Apply, this is because design disclosed in this invention and embodiment are not limited to any embodiment.In addition, disclosed by the invention one A little aspects can be used alone, or otherwise any appropriately combined be used with disclosed by the invention.
LED illumination of the present invention has the characteristics that：
Each LED illumination includes three LED luminescence units, with real respectively under the driving of same output voltage signal Existing RGB three-colour light-emittings, are finally realized white luminous.
As previously described, because the threshold voltage of RGB three-color LED luminescence units is there are notable difference, so in equal voltage Can there are brightness disproportionation phenomenon under driving.
With reference to Fig. 2, existing PWM compensation schemes are to use the square-wave signal with setting duty cycle, with the square-wave signal The luminous duration of control LED luminescence units is removed, so as to adjust the brightness of LED luminescence units.
Square-wave signal is realized by a PWM comparators at present, is generated a square-wave signal, is passed through different duty Square-wave signal controls the brightness of LED luminescence units to control LED luminescence units to have different luminous durations.Such as 90% duty cycle corresponds to the 90% of LED luminescence unit highest display brightness, and 10% duty cycle corresponds to LED luminescence unit highests The 10% of display brightness.
The duty cycle of foregoing square-wave signal is adjusted by a register, but there are problems with for the program：
The duty cycle adjustment mode precision of square-wave signal is low, it is difficult to realizes the fine setting of LED luminescence unit brightness.
The present invention introduces new compensation circuit on existing PWM compensation schemes, forms a new color error ratio and eliminates circuit, To realize the fine setting of square-wave signal duty cycle, and then realize the accurate control to LED luminescence unit brightness.
With reference to Fig. 3, the color error ratio eliminates circuit connected in series between output voltage signal and LED luminescence units, including Reference voltage generator, error amplifier, saw-toothed wave generator, PWM comparators, the first compensation circuit, field-effect tube, processing Device.
The drain electrode of the field-effect tube is electrically connected a regulated power supply, and source electrode is electrically connected a LED luminescence units.
The reference voltage generator is generating a reference voltage signal.
Further, the reference voltage signal is a burning voltage signal.
For example, reference voltage generator includes the voltage source using the generation of Bandgap principles.
The error amplifier includes a first input end, one second input terminal and an output terminal, wherein, first input end The output terminal of reference voltage generator is electrically connected to, the second input terminal is electrically connected to output voltage, the voltage letter of output terminal generation Number it is defined as error voltage signal.
For each LED luminescence units, one reference voltage, the threshold voltage of the reference voltage and affiliated LED luminescence units are set Correlation, output voltage and reference voltage generate error voltage signal through error amplifier, and error voltage signal and the LED shine list The proportional relation of error brightness that member should adjust.
It is to be converted into using by the error voltage signal in next step after the error voltage signal that should be adjusted is obtained In the square-wave signal with particular duty cycle for adjusting LED luminescence units, the present invention is realized by a saw-toothed wave generator.
The saw-toothed wave generator is generating a triangular signal.
The PWM comparators include two input terminals and an output terminal, wherein, two input terminals are respectively electrically connected to saw The output terminal of tooth wave producer, the output terminal of error amplifier, to relative error voltage signal and triangular signal, generation the One square-wave signal, by the output terminal of the first square wave signal transmission of generation to PWM comparators.
So far, most basic PWM compensation schemes are had been realized in, but the degree of regulation of the program is not high, can not realize LED The fine setting of luminescence unit brightness, for this reason, the present invention proposes the first compensation circuit of increase, does further PWM compensation.
First compensation circuit includes the PWM screened circuits and a register being electrically connected to each other, and PWM screened circuits are used To produce second square-wave signal with setting duty cycle with the first square-wave signal with frequency.
The processor is electrically connected to the first compensation circuit, and the second square wave is believed with realizing by adjusting the configuration of register The modulation of number duty cycle.
The output terminal of first compensation circuit is connected to the defeated of PWM comparators by a logical AND or logic or circuit Outlet, to modulate generation third party's ripple signal, third party's ripple signal is transferred to the grid of field-effect tube, is imitated to controlling filed Should pipe break-make, to realize to the brightness regulation of LED light.
For former PWM compensation schemes, the first compensation circuit added can mend the first square-wave signal Repay, such as 2% is cut in the fixed former duty cycle of original, to realize the fine setting to LED luminescence unit brightness.
When tri- groups of LED luminescence unit brightness disunities of RGB, the program can be used by discrepant one group of luminescence unit Carry out extra compensation.
The LED luminescence units are connected with an illumination photometer, and illumination photometer is electrically connected with processor, same to separately detect The brightness of three LED luminescence units in LED illumination, and result of detection is sent to processor；
The processor response does not meet setting brightness value in the brightness of wherein any one LED luminescence unit, and adjustment should The corresponding register of LED luminescence units.
Illumination photometer to detect the brightness of tri- groups of LED luminescence units of RGB, when find one of which LED luminescence units it is bright When degree and the brightness value of setting are not met, processor obtains luminance errors by calculating, and should through program set in advance adjustment The corresponding register of LED luminescence units, generates one second square-wave signal, adjusts the brightness of this group of LED luminescence unit, is come with this real It is existing with an automatic light meter.
When luminance errors is larger, it can first adjust the corresponding register realization of PWM comparators and significantly adjust, then adjust Save the fine setting of the corresponding register realization of PWM screened circuits by a small margin.
When luminance errors is smaller, the corresponding register of PWM screened circuits can be directly adjusted to realize fine setting.
In addition to the fine setting for realizing brightness, the first compensation circuit can also further widen the benefit of former PWM compensation schemes Scope is repaid, for example, increasing by 10% in the fixed former duty cycle of original, the further of LED luminescence unit brightness is increased with realizing By force.
In other examples, the color error ratio, which eliminates circuit, also has one second compensation circuit, to realize to base Plinth PWM compensation schemes are further compensate for.
Second compensation circuit includes an error voltage modulation circuit, its output terminal is electrically connected to the defeated of error amplifier Outlet, the second compensation circuit is to modulation error voltage signal, to change the duty cycle of the first square-wave signal.
The color error ratio, which eliminates circuit, also has one the 3rd compensation circuit.
3rd compensation circuit is a dynamic voltage signal maker, its output terminal is electrically connected to the of error amplifier One input terminal.
The color error ratio, which eliminates circuit, also has one the 4th compensation circuit.
The output terminal of 4th compensation circuit is electrically connected to the second input terminal of error amplifier, by output voltage End increases and decreases deviation voltage to change the duty cycle of the first square-wave signal.
Second compensation circuit, the 3rd compensation circuit, the 4th compensation circuit are to introduce to mend at the error voltage of analog portion Repay mechanism, specifically, error voltage, reference voltage, output voltage one or more at increase offset voltage, should Mode has preferably elasticity for the first compensation circuit, can arbitrarily adjust the original duty cycle of the first square-wave signal Percentage, such as 60%*95%=57% is adjusted to by 60% original duty cycle, this mode is imitated under low brightness condition Fruit is more preferable, is not likely to produce saturated phenomenon.
First compensation circuit, the second compensation circuit, the 3rd compensation circuit, the 4th compensation circuit can exist at the same time, also may be used With only exist one of them or it is several, set a variety of compensation circuits purpose be for realize to LED luminescence unit brightness Fine setting, original PWM compensation schemes are further compensate in other words, can arbitrarily be selected according to the actual requirements.
So as to which the present invention refers to that a kind of color error ratio for LED illumination eliminates circuit, can be adopted in IC interior RGB three-color LED brightness disproportionation phenomenons are solved with the PWM modes compensated, extra compensation resistance is not required in this mode, saves first device Part cost and pcb costs, in addition reduce consumption and are compensating ohmically power consumption, it is obvious to may be such that overall power declines.
Although the present invention is disclosed above with preferred embodiment, so it is not limited to the present invention.Skill belonging to the present invention Has usually intellectual in art field, without departing from the spirit and scope of the present invention, when can be used for a variety of modifications and variations.Cause This, the scope of protection of the present invention is defined by those of the claims.

Claims (7)

1. a kind of color error ratio for LED illumination eliminates circuit, each LED illumination includes three LED luminescence units, same To realize RGB three-colour light-emittings respectively under the driving of one output voltage signal, it is characterised in that the color error ratio eliminates circuit It is connected between output voltage signal and LED luminescence units, including reference voltage generator, error amplifier, sawtooth waveforms occur Device, PWM comparators, the first compensation circuit, field-effect tube, processor；
The drain electrode of the field-effect tube is electrically connected a regulated power supply, and source electrode is electrically connected a LED luminescence units；
The reference voltage generator is generating a reference voltage signal；
The error amplifier includes a first input end, one second input terminal and an output terminal, wherein, first input end is electrically connected The output terminal of reference voltage generator is connected to, the second input terminal is electrically connected to output voltage, the voltage signal quilt of output terminal generation It is defined as error voltage signal；
The saw-toothed wave generator is generating a triangular signal；
The PWM comparators include two input terminals and an output terminal, wherein, two input terminals are respectively electrically connected to sawtooth waveforms The output terminal of generator, the output terminal of error amplifier, to relative error voltage signal and triangular signal, generate first party Ripple signal, by the output terminal of the first square wave signal transmission of generation to PWM comparators；
First compensation circuit includes the PWM screened circuits and a register being electrically connected to each other, and PWM screened circuits are producing Raw second square-wave signal with setting duty cycle with the first square-wave signal with frequency；
The processor is electrically connected to the first compensation circuit, and the second square-wave signal is accounted for realizing by adjusting the configuration of register The modulation of empty ratio；
The output terminal of first compensation circuit is connected to the output of PWM comparators by a logical AND or logic or circuit End, to modulate generation third party's ripple signal, third party's ripple signal is transferred to the grid of field-effect tube, to control field-effect The break-make of pipe, to realize the brightness regulation to LED light.
2. the color error ratio according to claim 1 for LED illumination eliminates circuit, it is characterised in that the LED shines Unit is connected with an illumination photometer, and illumination photometer is electrically connected with processor, to separately detect three LED in same LED illumination The brightness of luminescence unit, and result of detection is sent to processor；
The processor response does not meet setting brightness value in the brightness of wherein any one LED luminescence unit, adjusts LED hairs The corresponding register of light unit.
3. the color error ratio according to claim 1 for LED illumination eliminates circuit, it is characterised in that the benchmark electricity Pressure signal is a burning voltage signal.
4. the color error ratio according to claim 3 for LED illumination eliminates circuit, it is characterised in that the benchmark electricity Maker is pressed to include the voltage source using the generation of Bandgap principles.
5. the color error ratio according to claim 1 for LED illumination eliminates circuit, it is characterised in that the color is inclined Difference, which eliminates circuit, also has one second compensation circuit；
Second compensation circuit includes an error voltage modulation circuit, its output terminal is electrically connected to the output of error amplifier End, the second compensation circuit is to modulation error voltage signal, to change the duty cycle of the first square-wave signal.
6. the color error ratio according to claim 1 for LED illumination eliminates circuit, it is characterised in that the color is inclined Difference, which eliminates circuit, also has one the 3rd compensation circuit；
3rd compensation circuit is a dynamic voltage signal maker, and it is first defeated to be electrically connected to error amplifier for its output terminal Enter end.
7. the color error ratio according to claim 1 for LED illumination eliminates circuit, it is characterised in that the color is inclined Difference, which eliminates circuit, also has one the 4th compensation circuit；
The output terminal of 4th compensation circuit is electrically connected to the second input terminal of error amplifier, by increasing in output voltage terminal Subtract deviation voltage to change the duty cycle of the first square-wave signal.
CN201711427781.2A 2017-12-26 2017-12-26 Color error ratio for LED illumination eliminates circuit Pending CN107995744A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201711427781.2A CN107995744A (en) 2017-12-26 2017-12-26 Color error ratio for LED illumination eliminates circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201711427781.2A CN107995744A (en) 2017-12-26 2017-12-26 Color error ratio for LED illumination eliminates circuit

Publications (1)

Publication Number Publication Date
CN107995744A true CN107995744A (en) 2018-05-04

Family

ID=62042759

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201711427781.2A Pending CN107995744A (en) 2017-12-26 2017-12-26 Color error ratio for LED illumination eliminates circuit

Country Status (1)

Country Link
CN (1) CN107995744A (en)

Similar Documents

Publication Publication Date Title
US7923943B2 (en) Secondary side post regulation for LED backlighting
US7479738B2 (en) Drive circuit for light emitting diode
EP1562170B1 (en) Display device adjusting method and display device
EP1672706B1 (en) Drive device for back light unit and drive method therefor
US7622697B2 (en) Brightness control for dynamic scanning backlight
WO2017088420A1 (en) Over-driving control method for local dimming and apparatus therefor
US7397205B2 (en) Illumination brightness and color control system and method therefor
US8120276B2 (en) Light source emitting mixed-colored light and method for controlling the color locus of such a light source
KR101000686B1 (en) Color management controller for constant color point in a field sequential lighting system
JP2009175659A (en) Backlight control apparatus
TW200713165A (en) LED light source for backlighting with integrated electronics
CN106101591B (en) The method of adjustment of LCD TV and its backlight driving voltage, device
US9135869B2 (en) Display signal generator, display device, and method of image display
CN211237683U (en) Backlight adjusting circuit and display device
US20070262731A1 (en) Regulating a Light Source Using a Light-to-Frequency Converter
CN101635131B (en) Backlight driving circuit and light source driving units thereof
CN101291557A (en) Method for driving light source, light source drive circuit, light source assembly and display device
CN101548312A (en) Gradation voltage correction system and display apparatus utilizing the same
CN101996587A (en) Color LED backlight frequency-control dimming circuit and method
CN101796886A (en) Backlight unit and display apparatus
CN101169920A (en) Display apparatus and control method thereof
CN110277059A (en) Driving chip and its control method, display device
US8093825B1 (en) Control circuit for optical transducers
CN101697272A (en) Device and method for correcting white balance of liquid crystal display equipment
CN107995744A (en) Color error ratio for LED illumination eliminates circuit

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination