CN110868773B

CN110868773B - Three-primary-color display unit, three-primary-color lamp bead and three-primary-color mixing method

Info

Publication number: CN110868773B
Application number: CN201911139957.3A
Authority: CN
Inventors: 孟豪; 费小泂
Original assignee: Cool Silicon Semiconductor Technology Shanghai Co ltd
Current assignee: Cool Silicon Semiconductor Technology Shanghai Co ltd
Priority date: 2019-11-20
Filing date: 2019-11-20
Publication date: 2021-08-06
Anticipated expiration: 2039-11-20
Also published as: CN110868773A

Abstract

The invention relates to a three-primary-color display unit, a three-primary-color lamp bead and a three-primary-color mixing method. The green and blue light emitting diodes are arranged in parallel. The red light emitting diode and both the green and blue light emitting diodes are arranged in series and are superimposed by the three primary colors red, green and blue to form white light or color. In the white light mode, the red, green and blue light emitting diodes are simultaneously lit such that the sum of a first current value flowing through the green light emitting diode and a second current value flowing through the blue light emitting diode is equal to a third current value flowing through the red light emitting diode. In the color mode, the respective lighting periods of the red, green, and blue light emitting diodes are set to overlap, and the respective lighting periods of the red, green, and blue light emitting diodes are set to be the same or different.

Description

Three-primary-color display unit, three-primary-color lamp bead and three-primary-color mixing method

Technical Field

The present invention relates generally to the field of displays, and more particularly to providing a three primary color display unit, a three primary color light bulb and a three primary color mixing method for a lighting or display scene containing solid state light emitting diodes.

Background

In the field of illumination display, the pulse dimming is to change the time width of lighting or turning off of a light emitting diode within a certain period of time and consider the current flowing through the light emitting diode during on-lighting to be a fixed value, thereby realizing a luminance change. According to the Grassmann's law and the standard chromaticity diagram of the International luminous Commission, the reference color component of the pixel point needs to be distributed in a preset intensity range in the lighting and display system, and all colors which can be perceived by a visual system can be obtained by depending on the gray scale change of the reference color and the superposition of different brightness. It is important how to ensure that the synthesized color meets the requirement, for example, after white is generated by mixing three primary colors of red, green and blue, the so-called white balance is an index for describing the accuracy of white. The white balance described in the application of display, imaging, lighting, and the like is an extremely important concept, and a series of problems such as color restoration and color tone processing can be solved by the white balance. On the contrary, if the white balance is not adjusted in place, there are many negative phenomena such as inaccurate color in the subsequent color change, for example, when the digital camera is used for shooting, the images shot in the room with the fluorescent lamp will appear green and the scenery shot under the indoor tungsten lamp will be yellow, and the photos shot in the sunshine shadow will be blue, which is due to the inaccurate white balance setting. Moreover, based on the color generated by mixing the three primary colors of red, green and blue, the current technical scheme generally provides the same power supply voltage for the light emitting diodes of the red, green and blue colors. In fact, the working voltages and the luminous efficiencies required by the light emitting diodes of the red, green and blue colors are different, and the application of the same power supply voltage to the light emitting diodes of the red, green and blue colors without discrimination can cause the low efficiency and the short service life of part of the light emitting diodes, which is the disadvantage brought by the inherent circuit topological structure and the packaging type of the traditional red, green and blue three-in-one lamp bead. Aiming at the pixel points with the preset topology, it is necessary to provide different working voltages for the red, green and blue light emitting diodes while realizing white balance.

Disclosure of Invention

The application relates to a three primary color display unit comprising: green and blue light emitting diodes connected in parallel; and a red light emitting diode arranged in series with both the green and blue light emitting diodes; white light or color is superposed by three primary colors of red, green and blue: in the white light mode, the red, green and blue light emitting diodes are simultaneously lighted, and the respective lighting time periods of the red, green and blue light emitting diodes are set to be coincident; alternatively, in the color mode, the respective lighting periods of the red, green, and blue light emitting diodes are set to overlap, and the respective lighting periods of the red, green, and blue light emitting diodes are set to be the same or different.

The above three primary color display unit, wherein: monochromatic colors are formed by three primary colors of red, green and blue:

under the monochromatic mode, the red, green and blue light emitting diodes are lighted in a time sharing mode, and the lighting time periods of the red, green and blue light emitting diodes are not overlapped.

The above three primary color display unit, wherein: the cathode of the red light emitting diode is coupled to the respective anodes of the green and blue light emitting diodes; or the anode of the red light emitting diode is coupled to the respective cathodes of the green and blue light emitting diodes.

The above three primary color display unit, wherein:

in the white light mode, the third current value, the first current value and the second current value have a preset proportional relation.

The above three primary color display unit, wherein:

the sum of the first current value flowing through the green light-emitting diode and the second current value flowing through the blue light-emitting diode is equal to a third current value flowing through the red light-emitting diode, and the preset proportional relation among the third current value, the first current value and the second current value comprises 8:5:3 or 8:4: 4.

The above three primary color display unit, wherein:

the green light-emitting diode and the blue light-emitting diode are connected with a first shunt branch in parallel, and the red light-emitting diode and another second shunt branch are connected in parallel;

in the color mode, the stage in which any one of the green and blue leds is turned off also simultaneously turns on the first shunting branch, and the stage in which the red led is turned off also simultaneously turns on the second shunting branch.

The above three primary color display unit, wherein:

in a color mode, a first current value provided for the green light emitting diode is switched between the green light emitting diode and the first current dividing branch, and a second current value provided for the blue light emitting diode is switched between the blue light emitting diode and the first current dividing branch; and a total current obtained by adding the first current value and the second current value is switched to flow between the red light-emitting diode and the second shunt branch.

The application relates to a three primary color light bead, comprising:

the LED package comprises a plastic package body with a light transmitting area and red, green and blue LEDs coated inside the plastic package body;

the light emitted by each of the red, green and blue light emitting diodes can be emitted from the light-transmitting area;

first to fourth pins extending from the inside to the outside of the plastic package body;

the anode and the cathode of the red light-emitting diode are correspondingly coupled to the first pin and the second pin respectively;

the anode and the cathode of the green light emitting diode are correspondingly coupled to the second pin and the third pin respectively;

the anode and the cathode of the blue light emitting diode are correspondingly coupled to the second pin and the fourth pin respectively;

white light or color is superposed by three primary colors of red, green and blue:

in the white light mode, the respective lighting time periods of the red, green and blue light emitting diodes are set to be coincident, and the sum of a first current value flowing through the green light emitting diode and a second current value flowing through the blue light emitting diode is equal to a third current value flowing through the red light emitting diode; or

In the color mode, the respective lighting periods of the red, green, and blue light emitting diodes are set to overlap, and the respective lighting periods of the red, green, and blue light emitting diodes are also set to be the same or different.

The present application relates to another three primary color light bulb comprising:

the anode and the cathode of the red light-emitting diode are correspondingly coupled to the third pin and the fourth pin respectively;

the anode and the cathode of the blue light emitting diode are correspondingly coupled to the first pin and the third pin respectively;

The application relates to a three-primary color mixing method, wherein:

connecting the green and blue light-emitting diodes in parallel and then connecting the green and blue light-emitting diodes in series with the red light-emitting diode;

simultaneously lightening the red, green and blue light emitting diodes, and generating white light by utilizing the superposition of three primary colors of red, green and blue;

adding a first current value flowing through the green light emitting diode and a second current value flowing through the blue light emitting diode to a third current value flowing through the red light emitting diode; and

the third current value, the first current value and the second current value have a preset proportional relation.

The method described above, wherein:

the preset proportional relation among the third current value, the first current value and the second current value comprises 8:5:3 or 8:4: 4.

The method described above, wherein:

coupling the cathode of the red light emitting diode to the respective anodes of the green and blue light emitting diodes; or

The anode of the red light emitting diode is coupled to the respective cathodes of the green and blue light emitting diodes.

The method described above, wherein: providing said first and second current values in the form of pulsed currents, during each cycle:

the first current value is loaded on the green light-emitting diode in the form of on-off pulse current;

the second current value is applied to the blue light emitting diode in the form of an on or off pulse current.

The application relates to another three primary color mixing method, wherein:

generating colors by superposition of three primary colors of red, green and blue;

the respective lighting periods of the red, green, and blue light emitting diodes are set to overlap, and the respective lighting periods of the red, green, and blue light emitting diodes are set to be the same or different.

The method described above, wherein:

The method described above, wherein: providing first and second current values in the form of pulsed currents, during each cycle:

determining the lighting time length of the first current value loaded on the green light-emitting diode by the duty ratio represented by the gray scale data matched to the green color;

determining the lighting time length of the second current value loaded on the blue light-emitting diode by the duty ratio represented by the gray scale data matched to the blue color;

the duty ratio represented by the gradation data matched to the red determines the lighting time period in which the total current including the first and second current values is applied to the red light emitting diode.

Drawings

To make the above objects, features and advantages more comprehensible, embodiments accompanied with figures are described in detail below, and features and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the following figures.

FIG. 1 shows a three-in-one lamp bead package type with independently powered red, green and blue LEDs.

Fig. 2 shows a common anode red, green and blue light emitting diode in a three-in-one lamp bead package type.

Fig. 3 shows a common cathode red, green and blue light emitting diode designed as a three-in-one lamp bead package.

Fig. 4 shows both green and blue leds connected in parallel and then in series with a red led.

FIG. 5 shows a parallel configuration of green and blue LEDs connected in series with a red LED to produce white light.

FIG. 6 shows that the green and blue LEDs can be turned on simultaneously to turn on the red LED.

Fig. 7 shows the green-blue led in parallel with the shunt branch and the red led in parallel with the shunt branch.

Fig. 8 is an example in which the respective lighting periods of the red and green and blue light emitting diodes may be set to overlap.

Fig. 9 is a view showing that three red, green and blue light emitting diodes are arranged to be lit up in a monochrome mode.

Fig. 10 is a waveform diagram of a modulation signal that is lit when three of red, green, and blue leds are arranged.

FIG. 11 shows that any one of the RGB LEDs is also synchronously connected in series to the voltage-dividing load when it is turned on.

Fig. 12 is an alternative embodiment in which leds are illuminated while also being connected in series to a voltage-divided load.

FIG. 13 is an embodiment of a green-blue LED with its anode coupled to the cathode of a red LED and packaged.

FIG. 14 is an example of a package with RGB LED display units and driver chips.

Fig. 15 is an example of a red led in series with a parallel configuration with green and blue leds.

Fig. 16 is a parallel arrangement of red leds with green and blue leds to produce white light.

Fig. 17 shows a red led in parallel with the shunt branch and a green-blue led in parallel with the shunt branch.

Fig. 18 is an example of lighting red, green, and blue light emitting diodes as a pull-up current in a monochrome mode.

Fig. 19 shows that any one of the primary leds is further connected in series with a voltage-dividing load when it is turned on in the form of a pull current.

FIG. 20 is an embodiment of a green-blue LED with its cathode coupled to the anode of a red LED and packaged.

Fig. 21 is an example of the integrated package of the driving chip and the three primary color display unit including rgb leds.

Fig. 22 is an embodiment in which a plurality of driving chips for driving red, green and blue light emitting diodes are arranged to be connected in parallel.

Fig. 23 is an embodiment in which a plurality of driving chips for driving red, green, and blue light emitting diodes are arranged to be connected in series.

Detailed Description

The present invention will be described more fully hereinafter with reference to the accompanying examples, which are intended to illustrate and not to limit the invention, but to cover all those embodiments, which may be learned by those skilled in the art without undue experimentation.

Referring to fig. 1, the core element of the three-in-one lamp bead with the three primary color light emitting diodes encapsulated therein includes a red light emitting diode, a green light emitting diode and a blue light emitting diode. The industry has developed abundant packaging structure in the packaging field of red, green and blue three-primary-color light emitting diodes, and has gradually transited from an earlier universal pin direct-insert type packaging structure to a more widely used surface-mount type packaging structure, and compared with a direct-insert type packaging structure and a surface-mount type packaging structure, the recently popular chip-on-board packaging has the characteristics of saving space, simplifying packaging technology and having more efficient heat management effect. These conventional or other not shown light emitting diode packages are commonly referred to as RGB full color LED packages. The package PAK mainly functions to encapsulate the rgb leds therein. Thermoplastic materials or thermosetting materials such as epoxy resins are the main raw materials of the package. The main function of the light-transmitting region LENS is to allow the light emitted from each of the three primary color light-emitting diodes to be emitted from the light-transmitting region. In other words, although the red, green and blue light emitting diodes are all encapsulated inside the encapsulation body, at least a partial encapsulation material which is limited to encapsulate each light emitting diode is made transparent. The epoxy resin colloid with the diffusant is an optional material of the LENS-shaped light-transmitting region LENS, and a silica gel material with better light transmittance can also be used as an optional material of the light-transmitting region, such as high-refractive transparent organic silica gel.

Referring to fig. 1, the conventional white light emitting diode and the three primary color light emitting diode have a special purpose, and the purpose is to achieve the effect of white light, the former is directly represented by white light, and the latter is formed by mixing red, green and blue light. In the aspect of displaying color, the red, green and blue mixed light can be matched with light rays in a specific wave band as desired, and in contrast, the white light emitting diode cannot cover full color. And moreover, the white light fluorescent powder light-emitting diode is obviously inferior to the light mixing effect of red, green and blue primary colors in the aspects of definition and color purity, and the three-in-one lamp bead has more advantages due to factors such as light attenuation problem, wafer manufacturing cost and the like. The mixed red, green and blue light has clear and bright image quality, has more diversified characteristics in light mixing, and can perfectly recover the most real color world, which is an irreplaceable advantage of the mixed three-primary-color light. The difficulty of mixing the primary colors red, green and blue is to produce white light of high quality and of considerable purity, which is one of the concerns to be solved herein.

Referring to fig. 1, the six-pin type three-in-one lamp bead includes six pins. The pin type mentioned herein includes a pin of an in-line package structure or a pin of a surface mount package structure or a pin of a chip-on-board package structure, etc. For the sake of brevity, the supporting components such as the lead frame or the base for carrying each led, and the connecting components such as the bonding wires for electrically connecting the anode or the cathode of the led to the leads are not separately illustrated in the drawings, and are not repeated in consideration of the contents and technical solutions thereof belonging to the common general knowledge in the led packaging industry. The anode and cathode of the red light emitting diode R are correspondingly electrically connected to the

pins

101A and 101C, respectively. And the anode and cathode of the green light emitting diode G are electrically connected to the

pins

102A and 102C, respectively, correspondingly. And the anode and cathode of the blue light emitting diode B are electrically connected to the leads 103A and 103C, respectively, correspondingly. For the six-pin type three-in-one lamp bead, power supply voltage is respectively applied to the anodes of the red, green and blue light emitting diodes. Although the red, green and blue light emitting diodes can independently control the power supply voltage and independently control the current flowing through each color of light emitting diode, the application range of the three-in-one lamp bead is limited by too many pins and too many adaptive wiring when the three-in-one lamp bead is used as a pixel point. The encapsulation type that in fact more accords with mainstream development trend and is close to the design specification is the full-color trinity lamp pearl of four foot formulas that contains four pins.

Referring to fig. 2, the four-pin type three-in-one lamp bead includes four pins. The pin type mentioned herein includes a pin of an in-line package structure or a pin of a surface mount package structure or a pin of a chip-on-board package structure, etc. In this example, the anodes of the red, green and blue leds are coupled together, in other words, the anodes of the leds are electrically connected to the same pin 200A but the cathodes of the leds are separated. The anode and cathode of the red light emitting diode R are correspondingly electrically connected to the

pins

200A and 201C, respectively. And the anode and cathode of green light emitting diode G are correspondingly electrically connected to

pins

200A and 202C, respectively. And the anode and cathode of the blue light emitting diode B are electrically connected to the

pins

200A and 203C, respectively, correspondingly. For the four-pin type three-in-one lamp bead, the power supply voltage is simultaneously applied to the anodes of the red, green and blue light emitting diodes. Although the red, green and blue leds can control the current flowing through each led individually but the supply voltage cannot be controlled individually, the characteristics of the red led determine that the required operating voltage is lower than that of the green and blue leds. The same supply voltage is applied directly or indirectly to the anodes of the rgb leds, which may cause low luminous efficiency: although the higher supply voltage can meet the working voltage requirements of the green and blue light emitting diodes, the efficiency of the red light emitting diode is low, and the red light emitting diode can generate overheating and light decay and other negative phenomena in an overvoltage environment after long-term operation.

Referring to fig. 3, a four-pin type three-in-one lamp bead containing four pins is also provided. The cathodes of the red, green and blue leds in this example are coupled to each other rather than the anodes described above. In other words, the cathodes of the light emitting diodes of each color are electrically connected to the same pin 300C but the anodes of the light emitting diodes of each color are separated. The anode and cathode of the red light emitting diode R are correspondingly electrically connected to the

pins

301A and 300C, respectively. And the anode and cathode of the green light emitting diode G are electrically connected to the

pins

302A and 300C, respectively, correspondingly. And the anode and cathode of the blue light emitting diode B are electrically connected to the

pins

303A and 300C, respectively, correspondingly. For the four-pin type three-in-one lamp bead, the respective outflow currents of the red, green and blue light emitting diodes are converged at a common cathode pin, and the same power supply voltage can be directly or indirectly applied to the anodes of the red, green and blue light emitting diodes. No matter be the trinity lamp pearl of total positive pole four-pin formula or the trinity lamp pearl of total negative pole four-pin formula or the trinity lamp pearl of six pin formulas all have the difficult problem that is difficult to overcome: i.e. it is difficult to produce high quality and reasonably pure white light. Moreover, for the triad pixel points of the predetermined circuit topology, it is necessary to provide white light and simultaneously provide differential working voltages for the red, green and blue light emitting diodes, so that the light emitting diodes of all colors operate in a working voltage environment conforming to the voltage characteristics of the light emitting diodes of all colors as much as possible. For example, the operating voltage of the red led is slightly lower than the operating voltage of the green and blue leds. Furthermore, if the topology of the pixel points is not changed when the three-in-one pixel points are switched from white light generation to color generation, the three-in-one pixel points still can provide different working voltages for the light emitting diodes with different colors, and obviously, the traditional common anode or common cathode three-in-one lamp beads or six-pin three-in-one lamp beads are not enough.

Referring to fig. 4, the core components of a three-primary color display unit or a three-primary color display circuit or a three-primary color pixel circuit mainly include a red light emitting diode, a green light emitting diode, and a blue light emitting diode: with green and blue light emitting diodes arranged in parallel connection, and a red light emitting diode arranged in series with the parallel arrangement with both green and blue light emitting diodes. The cathode of the red light emitting diode R is disposed in the display unit while being coupled to the anode of the green light emitting diode G and the anode of the blue light emitting diode B. The anode of the red light emitting diode R is coupled solely to terminal or pin 401. The cathode of green led G is coupled to terminal or pin 403 and the cathode of blue led B is provided coupled to terminal or pin 404. It is further provided that the anodes of the green leds G and the anodes of the blue leds B are both coupled to a common terminal or pin 402. The three primary color display unit 400 may incorporate electronic components such as resistors, etc., which may be used, in addition to the light emitting diodes of the respective primary colors.

Referring to fig. 4, based on solving the doubtful and troublesome problems faced by the conventional common-anode or common-cathode three-in-one lamp bead or six-pin three-in-one lamp bead, the three primary color display unit of the present example can provide pure white light or full color. The current flowing through the red led R is defined to have the third current value I3, the current flowing through the green led G is defined to have the first current value I1, and the current flowing through the blue led G is defined to have the second current value I2. Under the white light mode, the red, green and blue light emitting diodes are lighted at the same time, or the red, green and blue light emitting diodes are considered to be turned off or extinguished at the same time. The red light-emitting diode is driven to be turned on when the green-blue primary light-emitting diodes are powered on simultaneously, or the red light-emitting diode is driven to be turned off once the green-blue primary light-emitting diodes are turned off simultaneously. The present example requires that the sum of the first current I1 flowing through the green LED G and the second current I2 flowing through the blue LED B is equal to the third current I3 flowing through the red LED R. The mathematical formula is I1+ I2 ═ I3. In this case, the pin 402 coupled to the cathode of the red led and to the anode of the green-blue led is electrically floating, and current neither flows into nor out of the pin. As a preferred embodiment for improving the white light purity, the third current value I3, the first current value I1 and the second current value I2 have a predetermined proportional relationship in the white light mode. For example, a preset ratio relationship of I3: I1: I2 of the three may be claimed to be set to 8:5:3 or 8:4: 4. It is noted that the specific ratios used for illustration are only examples and are not meant to be limiting, and for example, alternative ratios of 7.9:4.8:3.1 or 8:4.1:3.9 are desirable alternatives and may also be used to improve the purity of white light. The white balance refers to the balance of white, namely the balance of the brightness proportion of red, green and blue, and the white balance effect is an important index of the display screen. The pure white is displayed only when the brightness ratio of the three primary colors is about 3:6:1 in terms of color. Color mismatch such as bluish and yellowish green color occurs when the actual luminance ratios of the primary colors are mismatched. The aforementioned predetermined ratio is also applicable to the color mode.

Referring to fig. 4, in the monochrome mode, the rgb leds are time-shared and constant-current lit, and it is required that the respective lighting periods of the red, green, and blue leds do not overlap each other. For example, the first current value, the second current value and the third current value are provided in the form of pulse current, and pulse current means that the first current value, the second current value and the third current value are periodically repeated and the current values are adjustable in magnitude. In an alternative example, it is assumed that in any one common period, the green led G is driven to light by the full-amplitude first current value I1 and then the green led G is extinguished by removing the first current value I1, then the blue led B is driven to light by the full-amplitude second current value I2 and then the blue led B is extinguished by removing the second current value I2, and then the red led R is driven to light by the full-amplitude third current value I3 and then the red led R is extinguished by removing the third current value I3. Therefore, the lighting time periods of the primary color light-emitting diodes are not overlapped, and the method is an example of time-sharing lighting of the three primary color light-emitting diodes.

Referring to fig. 4, the rgb leds are simultaneously constant-current-lit in the white light mode, so that the respective lighting periods of the red and green and blue leds coincide with each other. The first and second current values and the third current value are provided, for example, in the form of a pulse current, which means that the first and second current values and the third current value are periodically repeated and the current values are adjustable in magnitude. In an alternative example, it is assumed that the green led G is driven to light with the full-amplitude first current value I1 and the blue led B is driven to light with the full-amplitude second current value I2 in synchronization in any one common period, and then the green led G is turned off by removing the first current value I1 and the blue led B is turned off by removing the second current value I2 in synchronization. Alternatively, assuming that the green led G is driven to light by the full-amplitude first current value I1 and the blue led B is driven to light by the full-amplitude second current value I2 in any one common period, the green led G and the blue led B are kept on continuously throughout the period, i.e. the green led G is lit without removing the first current value I1 and the blue led B is lit without removing the second current value I2. Since the first current value I1 and the second current value I2 are combined to flow through the red light emitting diode, the third current value flowing through the red light emitting diode is changed in synchronization with the first current value I1 and the second current value I2 as long as the green light emitting diode G and the blue light emitting diode B are simultaneously turned on. It is satisfied that the sum of the first current value I1 flowing through the green led G and the second current value I2 flowing through the blue led B is equal to the third current value I3 flowing through the red led R. The same duty ratio of the respective lighting periods of the three primary color light emitting diodes and the coincidence of the lighting periods are typical examples of the simultaneous lighting or extinguishing of the three primary color light emitting diodes.

Referring to fig. 4, in the color mode, the respective constant current lighting periods of the rgb leds are set to overlap, and the respective lighting periods of the rgb leds are set to be the same or different. A first current value I1 is provided in the form of a pulsed current and a second current value I2 is provided in the form of a pulsed current. During each cycle period: the duty ratio characterized by the gray scale data matched to green determines the lighting time period that the first current value I1 is loaded on the green light emitting diode, the duty ratio characterized by the gray scale data matched to blue determines the lighting time period that the second current value I2 is loaded on the blue light emitting diode, and the duty ratio characterized by the gray scale data matched to red determines the lighting time period that the total current containing both the first and second current values I1 and I2 is loaded on the red light emitting diode. For example, at each cycle: the green light emitting diode G is driven to light by using a first current value I1 with full amplitude, the blue light emitting diode B is driven to light by using a second current value I2 with full amplitude synchronously, the red light emitting diode R is driven to light by using the total current synchronously, the first current value I1 is removed after the lighting time length determined by the gray scale data matched with the green color is finished to extinguish the green light emitting diode G, the second current value I2 is removed after the lighting time length determined by the gray scale data matched with the blue color is finished to extinguish the blue light emitting diode B, and the total current is removed after the lighting time length determined by the gray scale data matched with the red color is finished to extinguish the red light emitting diode R.

Referring to fig. 5, the display field generally uses pixel points or fluorescent points as basic display units, and each pixel point is mixed with red, green and blue to obtain full color. Three primary color mixing can constitute about sixteen million colors, provided that each color has eight bits of grayscale data, and the reference color of any single color will have 256 levels of grayscale. For another example, if each color has ten-bit gray scale data, then the reference color of any single color has 1024 levels of gray scale, and the three primary color mixture can constitute nearly about one billion colors. The gray scale determines the number of colors but the larger the gray scale is, the better. Grayscale data in the display field often carries duty cycle information. The exemplary three primary colors of the present application may be replaced with other colors. The RGB-LED three-in-one lamp beads are widely used in the fields of display screens, lighting, decoration, etc., the object driving chip 500 shown in the figure is often a constant current driving chip in the industry and has the functions of gray scale adjustment and brightness adjustment, and each output current channel is provided with the function of dimming by using a pulse width modulation signal. The driving chip 500 does not need a communication function if the driving chip 500 directly utilizes the locally stored gray-scale data to perform gray-scale adjustment, but needs to be equipped with a communication function if the driving chip 500 needs to receive external communication data to online capture the external gray-scale data and perform gray-scale adjustment. The display technology is more general, four or other transmission lines are adopted to realize the transmission of cascade signals, a clock signal line, a data signal line, a loading signal line and an output enabling signal line work together, communication data are sequentially transmitted in series and are mutually matched through four-line signals to realize the control of slave nodes of all the cascades. A communication protocol using three lines of data lines and clock and latch lines is also the mainstream communication scheme for display technology. When the pixel pitch is larger, double-line transmission is adopted, and the double-line transmission of a data line and a clock line is the compromise between the number of data lines and the transmission rate. Although a multi-wire communication protocol commonly used in the industry is suitable for the communication function of the driver chip of the present application and thereby transfers communication data, a substantially alternative single-wire communication is more suitable as a preferred embodiment for the data transmission of the present application and the advantage of the single-wire protocol is that only a single data wire is required for the cascaded data transmission.

Referring to fig. 5, although a driving chip 500 in the form of an integrated circuit is illustrated as a typical example of driving the light-emitting diode light source to light up. It is to be emphasized that this does not mean that the driver circuit can only be designed as an integrated circuit since discrete electronic components can also build a functionally identical driver circuit. The driver circuit can be designed either as an integrated chip or built up from discrete electronic components. The data transmission module TRAN of the driver chip 500 has the same decoding function as the later mentioned data transmission module of the current source ICS: the difference is that the former needs to decode the gray data from the received communication data, while the latter needs to decode the current regulation data, and in fact, both the current regulation data and the gray data are the signals with preset coding rules in the communication data are restored to the common binary data by the decoder, and they can decode the input serial data according to the preset communication protocol. This also supports the diversity of data recipients, both current sources and driver chips. Circuits, such as over-temperature protection, start-up protection, electrostatic protection, transient voltage protection, and peak current leakage circuit, etc., which play a basic protection role, as well as oscillators, power-on reset circuits, and even clock circuits, etc., all belong to optional or necessary functions of the chip, and are well known by those skilled in the art, and therefore, they are not described in detail.

Referring to fig. 5, the essence of pulse width modulation is to convert the amplitude of a signal into the amount of time of the signal, and the implementation mechanism of pulse width modulation generally includes technical routes such as a count comparison mode, a delay unit mode, a shift mode, a mixed mode of count comparison and delay unit, and the like, and the pulse width signal with a certain duty ratio is obtained in any mode. The so-called digital pulse width modulation, DPWM, in the industry is within the scope of the prior art. The pulse width modulation module of the driving chip 500 may form a pulse width modulation signal according to the gray data, and the gray data is used to determine the duty ratio of the pulse width modulation signal, i.e., the pulse width modulation signal is considered to represent the duty ratio information carried by the gray data. The driving chip is also called a display control chip, and the red, green and blue three-primary-color light emitting diodes can be driven by the driving chip to be lighted and color-adjusted, for example.

Referring to fig. 5, only three-way leds are illustrated for ease of explanation, it being understood that the specific number of light sources is not to be construed as limiting in any way and is for reference only. The driving chip 500 decodes the communication data to obtain the required gray data, and the first pulse width modulation module of the pulse width modulation module PWM forms the first path of pulse width modulation signal D1 corresponding to the first path of light emitting diode G according to the gray data allocated to the first path of light emitting diode G. And the second pulse width modulation module forms a second pulse width modulation signal D2 corresponding to the second LED B according to the gray scale data distributed to the second LED B. Each specific pulse width modulation module in the pulse width modulation module PWM forms a corresponding path of pulse width modulation signal according to the gray scale data matched with the corresponding path of light emitting diode: i.e. a pulse width modulated signal corresponding to each light emitting diode is formed according to the gray scale data assigned to each light emitting diode. The gray scale data assigned to the first LED G and the gray scale data assigned to the second LED B are allowed to be the same value in the white light mode. Let them all equal the gray scale data defined for white light. The on-off state of the third led R follows the on-off states of the first led G and the second led B, so it is obvious that the gray scale data assigned to the third led R and the gray scale data assigned to the first led G are the same numerical value, and the gray scale data assigned to the second led B are the same numerical value. In an embodiment for generating white light, the duty cycles of the first and second pulse width modulated signals are determined to be 50% if the duty cycle characterized by the gray scale data defined for the white light is 50%. For the same reason, if the duty cycle characterized by the gray scale data defined for white light is 90%, the duty cycles of the first and second pulse width modulated signals are 90%. In the white light mode, it can be considered that the duty ratios of the first and second pwm signals are adjusted by the gray scale data matched to the white light, which is also equivalent to indirectly adjusting the on-off duty ratio of the third led R. The gray scale data defined for white light in this example is in fact directly equal to the gray scale data assigned to green, directly equal to the gray scale data assigned to blue, and indirectly equal to the gray scale data assigned to red. The gray scale data defined for the white light determines the on-off duty cycle of the first path of light emitting diode G and determines the on-off duty cycle of the second path of light emitting diode B and the third path of light emitting diode R.

Referring to fig. 5, a first light emitting diode G is connected in series with a constant current unit CS1, and it is noted that a constant current unit CS1 generating a constant current is controlled by a first pulse width modulation signal D1. The first pwm signal D1 determines the constant current lighting time of the first led in the period of the first pwm signal D1. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the first pwm signal D1 has a high logic level, the constant current is applied to the first led G, and when the current is off, for example, the first pwm signal D1 has a low logic level, the constant current is disconnected from the first led G. The pin 403 of the three-in-one lamp bead is coupled to the pin 503 of the driving chip 500, a constant current unit CS1 is arranged between the pin 503 of the driving chip 500 and the potential reference terminal GND of the driving chip, and the constant current unit CS1 can provide a first current value I1.

Referring to fig. 5, the second led B is provided in series with the constant current unit CS2, and it is noted that the constant current unit CS2 generating a constant current is controlled by the second pwm signal D2. The second pwm signal D2 determines the constant current lighting time of the second led in the period of the second pwm signal D2. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the second pwm signal D2 has high logic level, the constant current is applied to the second led B, and when the current is off, for example, the second pwm signal D2 has low logic level, the constant current is disconnected from the second led B. The pin 404 of trinity full-color lamp pearl is coupled to the pin 504 of driver chip 500, is provided with constant current unit CS2 between the pin 504 of driver chip 500 and the potential reference end GND of driver chip, and constant current unit CS2 can provide second current value I2.

Referring to fig. 5, a compact scheme is that each light emitting diode and one constant current unit are coupled in series between a power input terminal and a potential reference terminal. In the figure, the light emitting diodes R and G and the constant current unit CS1 are connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diodes R and B and the constant current unit CS2 are connected in series between the power input terminal VCC and the potential reference terminal GND. The anode of the led R, i.e., the pin 401, is coupled to the power input VCC at the pin 501 of the driver chip 500, so that the led of each primary color is directly powered by the input voltage or power supply voltage at the power input VCC. A shunt module, which is not shown in the figure, can also be connected in series between the supply input VCC and the potential reference GND. The input voltage at the power input terminal VCC is a power supply for driving other functional modules in the chip, in addition to being a power supply for the light source. The first and second current values are both constant currents.

Referring to fig. 5, the circuit architecture is by no means the only solution, and the positions of each light emitting diode and the corresponding constant current unit can be interchanged to meet the requirement of sinking current or sourcing current of the driving chip. Besides, the input voltage of the power input end VCC can be directly utilized or the power supply can be used for supplying power to the light emitting diodes, and the divided voltage of the input voltage at the power input end VCC can also be used for supplying power to each path of light emitting diodes. In an alternative example, the light emitting diode serial group and the corresponding one of the constant current units are coupled in series between the divided voltage of the input voltage and the potential reference terminal. In other examples, a stable voltage obtained by performing voltage conversion on the input voltage provided at the power input terminal VCC, such as linear or switch type or charge pump type, may be used to supply power to each of the light emitting diodes, and the light emitting diode serial group and the corresponding one of the constant current units are coupled in series between the stable voltage obtained by voltage conversion and the potential reference terminal.

Referring to fig. 5, allowing the driver chips and the current source modules described later to be cascade-connected to each other also allows the driver chips to be cascade-connected to each other so that they each have a data forwarding function. One of the core functions of the driving chip is to drive the multiple light emitting diodes matched with the driving chip to light up according to the display requirement: when the three primary colors are added and mixed, the relative brightness ratio of the three primary colors of red, green and blue is changed to obtain different colors. When the three primary colors are mixed, the lighting time of the red, green and blue light emitting diodes in the cycle period is changed to change the brightness ratio of the light emitting diodes with various colors, which is equivalent to changing the relative brightness ratio of the three primary colors, so that different colors can be obtained when the gray scale of the light emitting diodes is changed. The data transmission module TRAN of the driver chip 500 decodes the input serial data according to a predetermined communication protocol, decodes the gray data and the like from the received communication data, and adjusts the color of the pixel points according to the gray data assigned to the red, green and blue leds, respectively. The signal input end DI receives communication data provided from outside and the data transmission module TRAN needs to decode data information carried in the communication data, and the meaning of data decoding is that data in a pre-coding format which cannot be directly displayed by the light emitting diode can be restored to a conventional binary code which is easy to recognize and execute. The binary code obtained by decoding is temporarily stored in a shift register, and considering that the data refreshing of the register is fast and needs to be updated frequently, a buffer or a latch is used for storing the decoded data and the pulse width modulation module PWM reads the gray data from the latch, and the pulse width modulation module PWM generates a pulse width signal according to the gray data. The techniques such as return-to-one code, return-to-zero code, or manchester encoding and decoding are all common single-wire communication protocols for communication data transmission and encoding and decoding.

Referring to fig. 5, the driver chip 500 further undertakes data regeneration or data forwarding by the data transmission module TRAN to complete data forwarding tasks such as communicating communication data to the rear driver chip. Although not shown in the figure, the simplest forwarding mode is transparent transmission or direct transmission, which allows the communication data received by the signal input terminal DI to be directly output from the signal output terminal DO, and then the driving chip 500 or the current source ICS connected in cascade are used to extract the communication data corresponding to its own address and belonging to its own address from the single data line according to their respective address allocation rules. In the transparent transmission mode, communication data seen by each slave node is identical, and each slave node only intercepts own data, so that the communication data has to contain address information of each slave node, which causes the communication data to be bulky and requires a driver chip to use more circuits. The alternative forwarding scheme needs to cooperate with statistics of communication data belonging to each stage of driving chip, and after intercepting the communication data belonging to each stage of driving chip in each frame of communication data, each stage of driving chip forwards the rest of other received communication data to a next-stage communication data receiver cascaded with the driving chip, wherein the next-stage communication data receiver can be a next-stage driving chip or a current source module. Each driver chip counts whether the total bit number of the communication data belonging to the driver chip is completely received, and if the communication data belonging to the driver chip is decoded and completely received by the driver chip, that is, the statistical result of the total bit number reaches the expected number, the driver chip 500 forwards the communication data received by the signal input terminal DI of the driver chip from the signal output terminal DO. The counter can be used for counting whether the total bit number of the communication data belonging to the driving chip is completely received or not, and the data transmission module TRAN of the driving chip plays a role of a switch for allowing the received communication data to be forwarded and output or not under the condition.

Referring to fig. 6, the green led G is driven to light up with the full-amplitude first current value I1 and the blue led B is driven to light up with the full-amplitude second current value I2 in any one common period TPWM < N >, where N is a natural number. The constant current unit CS1 generating a constant current, i.e., a first current value I1, is controlled by the first pwm signal D1, and the constant current unit CS2 generating a constant current, i.e., a second current value I2, is controlled by the second pwm signal D2. The first pwm signal D1 and the second pwm signal D2 are synchronous signals and have logic high level and logic low level simultaneously in a common period. The first and second pulse width modulated signals characterize duty cycle information carried by the gray scale data suitable for white light. It is meant that the driving chip can determine the duty ratio of the first and second pwm signals according to the gray scale data suitable for white light. For example, assuming that the gray scale data matched to the white light determines that the duty ratio of the first and second pulse width modulation signals is 90%, the average current flowing through the green light emitting diode G in a period is the first current value I1 multiplied by 90%, and the average current flowing through the blue light emitting diode B in a period is the second current value I2 multiplied by 90%. It has been described above that the third current value I3 flowing through the red led varies synchronously with the first current value I1 and the second current value I2, and the average current flowing through the red led R in the cycle is the sum of the first current value I1 and the second current value I2 multiplied by 90%. In the white light mode, the switching of the red led R is allowed to be controlled directly without any pwm signal, and in fact, the red led R is only indirectly controlled by the first and second pwm signals. The duty cycles of the first and second pulse width modulated signals in any one common period may be set to be identical, provided that the end of the previous common period TPWM < N > is followed by the next adjacent common period TPWM < N +1 >. In contrast, in general, the duty ratio of the first and second pwm signals in the last common period may be set to be different from the duty ratio of the first and second pwm signals in the next common period, as long as the duty ratio information carried by the gradation data is changed.

Referring to fig. 6, first and second current values in the form of pulsed currents are provided and during a common cycle period: in the white light mode, a first current value is applied to the green light-emitting diode in the form of an on-off pulse current, and a second current value is applied to the blue light-emitting diode in the form of an on-off pulse current. The sum of the first current value and the second current value, i.e. the third current value, is naturally also applied to the red light-emitting diode in the form of an on-or off-pulsed current. The driving chip can be used for driving the red, green and blue light emitting diodes, the driving chip can provide a first current value and a second current value, a first pulse width modulation signal generated by the driving chip can be used for controlling the turn-off or turn-on state of the first current value, and a second pulse width modulation signal generated by the driving chip can be used for controlling the turn-off or turn-on state of the second current value. The duty cycle of the first width modulation signal and the duty cycle of the second pulse width modulation signal are both adjustable.

Referring to fig. 7, a first PWM module of the PWM module in the driver chip 500 forms a first PWM signal D1 corresponding to the first led G according to the gray scale data assigned to the first led G. The second PWM module of the PWM module in the driver chip 500 forms a second PWM signal D2 corresponding to the second led B according to the gray data assigned to the second led B. The third PWM module of the PWM module PWM in the driver chip 500 forms a third PWM signal D3 corresponding to the third led R according to the gray scale data assigned to the third led R. Note that the three multi-way switches S01, S02 and S03 are controlled by the first pwm signal D1, the second pwm signal D2 and the third pwm signal D3, respectively.

Referring to fig. 7, the pin 401 of the display unit is connected to the power input terminal VCC of the driving chip 500 and the constant current units CS1 and CS2 are provided between the pin 402 of the display unit and the potential reference terminal GND. For example, the pin 401 is specifically coupled to the power input VCC by being connected to a pin 501 of the driver chip 500, and the pin 402 is specifically connected to a pin 502 of the driver chip 500. And further, a voltage reference terminal GND of the driving chip 500 is connected in series between the pin 502 of the driving chip and the voltage reference terminal GND: a constant current unit CS1 and an adjustable shunt reference source Z1 and a second link switch belonging to a multi-way switch S01. And further, there are connected in series between the pin 503 of the driving chip 500 and the potential reference terminal GND of the driving chip: a constant current unit CS1, and a first link switch belonging to the multi-way switch S01. Further, a voltage reference terminal GND is connected in series between the pin 502 of the driver chip 500: a constant current unit CS2, an adjustable shunt reference source Z1 and a second link switch belonging to a multi-way switch S02. The pin 504 of the driving chip 500 is connected in series with the potential reference terminal GND: a constant current unit CS2, and a first link switch belonging to the multi-way switch S02. In addition, a first link switch belonging to the multi-way switch S03 is further disposed between the pin 501 of the driver chip 500 and the power input terminal VCC, and a series connection is also provided between the power input terminal VCC and the pin 502: an adjustable shunt reference source Z2 and a second link switch belonging to the multi-way switch S03. Terms such as an adjustable shunt reference voltage source, an adjustable precision shunt regulator, a programmable reference source circuit, a three-terminal programmable shunt regulator, or a programmable shunt type voltage reference source are used to describe the adjustable shunt reference source, but the nomenclature is slightly different, and the adjustable shunt reference source is generally considered to have three terminals, which are respectively named as a cathode k (cathode), an anode a (anode), and a reference terminal ref (reference). The adjustable shunt reference source Z2 can also adjust and stabilize the voltage at two ends of the red light-emitting diode, and the adjustable shunt reference source Z1 can also adjust and stabilize the voltage at two ends of the green and blue light-emitting diodes, thereby playing the role of shunt and voltage stabilization.

Referring to fig. 7, an adjustable shunt reference source Z2 is connected in parallel with the red led. The multi-way switch S03 is controlled by the third pwm signal D3. When the third pwm signal D3 has a valid logic value, the anode of the illuminated red led is connected to the supply voltage, and the total current obtained by adding the first current value and the second current value flows through the red led. Otherwise, when the third pwm signal D3 has an invalid logic value, the red led is turned off, the total current obtained by adding the first and second current values flows through the adjustable shunt reference source Z2, the cathode K of the adjustable shunt reference source Z2 is connected to the supply voltage, the anode a of the adjustable shunt reference source Z2 is coupled to the respective anodes of the green and blue leds, and the anode a of the adjustable shunt reference source Z2 is coupled to the cathode of the red led. A resistive voltage divider, not shown, may be connected between the cathode K and the anode a of the adjustable shunt reference source Z2, the resistive voltage divider comprising two resistors and a voltage dividing node at the interconnection of the two resistors may be coupled to the reference terminal REF of the adjustable shunt reference source Z2.

Referring to fig. 7, an adjustable shunt reference source Z1 is connected in parallel with the green led. The multi-way switch S01 is controlled by the first pwm signal D1. The cathode of the green LED that is lighted when the first PWM signal D1 has a valid logic value is connected to the constant current unit CS1, and the first link switch of the multi-way switch S01 is turned on to let the first current value flow through the green LED. On the contrary, when the first pulse-width modulation signal D1 has a non-valid logic value, the green led is turned off, the second link switch of the multi-way switch S01 is turned on, and the first current value flows through the adjustable shunt reference source Z1, at this time, the anode a of the adjustable shunt reference source Z1 is connected to the constant current unit CS1, the cathode K of the adjustable shunt reference source Z1 is coupled to the cathode of the red led, and the cathode K of the adjustable shunt reference source Z1 is coupled to the anode a of the adjustable shunt reference source Z2. An additional unillustrated resistor divider may also be connected between the cathode K and the anode A of the adjustable shunt reference source Z1, the resistor divider comprising two resistors and a voltage dividing node at the interconnection of the two resistors being coupleable to the reference terminal REF of the adjustable shunt reference source Z1.

Referring to fig. 7, an adjustable shunt reference source Z1 is connected in parallel with the blue led. The multi-way switch S02 is controlled by the second pulse-width modulation signal D2. The cathode of the blue LED that is turned on when the second PWM signal D2 has a valid logic value is connected to the constant current unit CS2, and the first chain switch of the multi-way switch S02 is turned on to let the second current value flow through the blue LED. Otherwise, when the second channel of pwm signal D2 has a non-valid logic value, the blue led is turned off, and the second link switch of the multi-way switch S02 is turned on to let the second current value flow through the adjustable shunt reference source Z1, at this time, the anode a of the adjustable shunt reference source Z1 is connected to the constant current unit CS2 and the cathode K of the adjustable shunt reference source Z1 is coupled to the cathode of the red led, and the cathode K of the adjustable shunt reference source Z1 is coupled to the anode a of the adjustable shunt reference source Z2. It is noted that if both the blue and green leds are turned off, the first current value and the second current value simultaneously flow through the adjustable shunt reference source Z1, causing the second link switch of the multi-way switch S01 to be turned on and the second link switch of the multi-way switch S02 to be turned on.

Referring to fig. 7, the rgb leds are simultaneously constant-current-lit in the white light mode, so that the respective lighting periods of the red and green and blue leds coincide with each other. For example, if the first link switch of the multi-way switch S01 is turned on and the first link switch of the multi-way switch S02 is turned on and the first link switch of the multi-way switch S03 is turned on, which corresponds to the pin 402 being electrically floating, the sum of the first current value I1 flowing through the green led and the second current value I2 flowing through the blue led is equal to the third current value flowing through the red led.

Referring to fig. 7, the primary color leds are sequentially lit in time division: when the third pwm signal D3 has a valid logic value, if it is high, the first link switch of the multi-way switch S03 is turned on, and when the third pwm signal D3 has a valid logic value, the second link switch of the multi-way switch S01 and/or S02 is turned on. When the first pwm signal D1 has a high logic value, the first link switch of the multi-way switch S01 is turned on, and when the first pwm signal D1 has a high logic value, the second link switch of the multi-way switch S03 is turned on. When the second pwm signal D2 has a high logic value, the first link switch of the multi-way switch S02 is turned on, and when the second pwm signal D2 has a high logic value, the second link switch of the multi-way switch S03 is turned on. So that the three-color light-emitting diodes in a certain total time period are sequentially lightened in a time-sharing manner: the red led is turned on when the pwm signal D3 has an active logic value in the first sub-period T1, the green led is turned on when the pwm signal D1 has an active logic value in the second sub-period T2, and the blue led is turned on when the pwm signal D2 has an active logic value in the third sub-period T3. The result is that the red LEDs will not light up in T2-T3, and the green LEDs will not light up in T1 and T3, and the blue LEDs will not light up in T1 and T2. The desired result of the red and green and blue leds being time-shared lit in the monochrome mode is achieved. The effective logic value, e.g., the duty ratio of high level, of the third pwm signal D3 is adjusted in the first sub-period T1, the effective logic value, e.g., the duty ratio of high level, of the first pwm signal D1 is adjusted in the second sub-period T2, and the effective logic value, e.g., the duty ratio of high level, of the second pwm signal D2 is adjusted in the third sub-period T3. Besides the time-sharing lighting sequence of red, green, blue, green, red, blue, green, blue, red, blue, green, blue and green, the order of the high level of the first to the third pulse width modulation signals is reasonably arranged as a countermeasure.

Referring to fig. 7, in an alternative embodiment, it may be claimed that the green light emitting diode is arranged in parallel with one first shunt branch and the blue light emitting diode is arranged in parallel with the first shunt branch, while the red light emitting diode is arranged in parallel with the other second shunt branch. In an alternative embodiment, the first tap branch may employ, for example, the adjustable tap reference source Z1 described above, and the second tap branch may employ, for example, the adjustable tap reference source Z2 described above. In an alternative embodiment, the first shunt leg uses a resistor and the second shunt leg uses another resistor, such as replacing the adjustable shunt reference source Z1 described above with one resistor and the adjustable shunt reference source Z2 with another resistor. Even the first shunt branch may use a conventional diode in forward conduction while the second shunt branch uses another conventional diode, for example, replacing the aforementioned adjustable shunt reference source Z1 with a conventional diode and the adjustable shunt reference source Z2 with a conventional diode. In the color mode, the first current value I1 flows directly through the green light-emitting diode during the period when the green light-emitting diode is turned off and during the period when the green light-emitting diode is turned on, so that the first current value I1 switches between the green light-emitting diode and the first current-dividing branch, and the first current value I1 flows through either the green light-emitting diode or the first current-dividing branch, i.e., so-called switching of the first current value I1 is achieved. According to the same principle, in the same color mode, the first shunt branch is also simultaneously turned on in the phase when the blue light emitting diode is turned off, and the second current value I2 directly flows through the blue light emitting diode in the phase when the blue light emitting diode is turned on, so that the second current value I2 is switched to flow between the blue light emitting diode and the first shunt branch, and the second current value I2 flows through either the blue light emitting diode or the first shunt branch, that is, so-called switching flow of the second current value I2 is realized. In the same way, in the same manner, during the color mode, the second shunt branch is also switched on simultaneously during the phase when the red light-emitting diode is switched off, and the total current value resulting from the addition of the first and second current values during the phase when the red light-emitting diode is lit is passed directly through the red light-emitting diode, so that as a result the total current value resulting from the addition of the first and second current values, I1+ I2 flowing either through the red light-emitting diode or through the second shunt branch, i.e. the so-called switched flow of the total current value I1+ I2 resulting from the addition of the first and second current values, is switched to flow between the red light-emitting diode and the second shunt branch. In the display field, the on-off of current can generate serious electromagnetic interference when brightness and color are modulated by a pulse width modulation method, and the problem of electromagnetic interference is also one of the great disadvantages of the traditional lamp beads. In addition, the lamp bead and the matched driving chip thereof pursue the stability of voltage and current between the power supply input end and the potential reference end in many application scenes. The switching and circulating scheme of the constant current can inhibit electromagnetic interference to a great extent and ensure the current and voltage stability of the lamp bead and the matched driving chip. Allowing the first and second shunting branches to be integrated into the driver chip also allows the first and second shunting branches to be used in combination with the three primary color display elements separately.

Referring to fig. 8, in the color mode, the high level period of the third pwm signal D3 may light the red led and the high level period of the first pwm signal D1 may light the green led, and similarly, the high level period of the second pwm signal D2 may light the blue led. The respective lighting periods of the red, green and blue light emitting diodes are set to overlap in each common cycle period, that is, the high level periods corresponding to the three pulse width modulation signals overlap with each other, and the respective lighting periods of the red, green and blue light emitting diodes may also be set to be the same or different in each cycle period. And the respective lighting time duration of the red, green and blue three primary color light emitting diodes is determined by the respective duty ratio of the first to third pulse width modulation signals D1 to D3. The special case of the color mode is that the duty cycles of the first to third pwm signals D1 to D3 are identical, and then since the rgb leds are simultaneously turned on and their respective turn-on periods are coincident, and the respective turn-on periods of the red, green, and blue leds are identical, the sum of the first current value flowing through the green led and the second current value flowing through the blue led is equal to the current flowing through the red led, and white light may be generated.

Referring to fig. 9, a first light emitting diode G is connected in series with a constant current unit CS1, and it is noted that a constant current unit CS1 generating a constant current is controlled by a first pulse width modulation signal D1. The first pwm signal D1 determines the constant current lighting time of the first led in the period of the first pwm signal D1. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the first pwm signal D1 has a high logic level, the constant current is applied to the first led G, and when the current is off, for example, the first pwm signal D1 has a low logic level, the constant current is disconnected from the first led G. The pin 403 of the three-in-one lamp bead is coupled to the pin 513 of the driving chip 500, a constant current unit CS1 is arranged between the pin 513 of the driving chip 500 and the potential reference terminal GND of the driving chip, and the constant current unit CS1 can provide a first current value I1.

Referring to fig. 9, the second led B is provided in series with the constant current unit CS2, and it is noted that the constant current unit CS2 generating a constant current is controlled by the second pwm signal D2. The second pwm signal D2 determines the constant current lighting time of the second led in the period of the second pwm signal D2. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the second pwm signal D2 has high logic level, the constant current is applied to the second led B, and when the current is off, for example, the second pwm signal D2 has low logic level, the constant current is disconnected from the second led B. Pin 404 of trinity full-color lamp pearl is coupled to drive chip 500's pin 514, is provided with constant current unit CS2 between drive chip 500's pin 514 and drive chip's the electric potential reference end GND, and constant current unit CS2 can provide second current value I2.

Referring to fig. 9, the third light emitting diode R and the constant current unit CS3 are provided in series, and it is noted that the constant current unit CS3 generating a constant current is controlled by the third pulse width modulation signal D3. The third pwm signal D3 determines the constant current lighting time of the third led in the cycle of the second pwm signal D3. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the third pwm signal D3 has a high logic level, the constant current is applied to the third led R, and when the current is off, for example, the third pwm signal D3 has a low logic level, the constant current is disconnected from the third led R. Pin 402 of trinity full-color lamp pearl is coupled to drive chip 500's pin 512, is provided with constant current unit CS3 between drive chip 500's pin 512 and drive chip's the electric potential reference end GND, and constant current unit CS3 can provide third current value I3.

Referring to fig. 9, a compact scheme is that each light emitting diode and one constant current unit are coupled in series between a power input terminal and a potential reference terminal. The light emitting diode R and the constant current unit CS3 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diode B and the constant current unit CS2 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diode G and the constant current unit CS1 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND. The anode of the led R, i.e., the pin 401, is coupled to the power input VCC at the pin 511 of the driver chip 500, thereby directly utilizing the input voltage or the power supply voltage at the power input VCC for the red led. A shunt module, which is not shown in the figure, can also be connected in series between the supply input VCC and the potential reference GND. The input voltage at the power input terminal VCC is a power supply for driving other functional modules in the chip, in addition to being a power supply for the light source. The stable voltage obtained by performing linear or switch type or charge pump type voltage conversion on the input voltage at the power input end can also supply power to each light emitting diode.

Referring to fig. 9, the red and green and blue leds are time-divisionally lit in the monochrome mode. The red led is coupled to the power input VCC by pin 401 when it is lit, so as to switch in or input a supply voltage to the red led and to provide a current flowing through the red led from pin 402. In the same way, the green led is illuminated by coupling pin 402 to the power input VCC to switch in or input the supply voltage to the green led and provide current through the green led from pin 403. In the same way, the blue led is illuminated by coupling pin 402 to the power input VCC to provide a supply voltage to the blue led and a current through the blue led from pin 404. In the white light mode, a power supply voltage is input from the pin 401, a first current value flowing through the green led is provided from the pin 403, a second current value flowing through the blue led is provided from the pin 404, a third current value flowing through the red led is equal to the sum of the first current value and the second current value, and the white light mode requires the pin 402 to be floated, similar to the embodiment of fig. 5.

Referring to fig. 9, the previous example and the present example both provide a first current value to the green led and a second current value to the blue led and a third current value to the red led. In contrast, the third current value is directly provided by the independent constant current unit in the present example, and the total current obtained by adding the first current value and the second current value is required to be indirectly regarded as the third current value in the previous example, which are allowed in both cases. Even allowing the constant current unit supplying the first current value to switch to supply the current alone to the red light emitting diode or allowing the constant current unit supplying the second current value to switch to supply the current alone to the red light emitting diode is an alternative embodiment.

Referring to fig. 10, each of the pwm signals D1, D2, and D3 is time-divided into high-level or light-divided signals that are lit in a plurality of sub-periods T1-T3 as shown. And the effective logic values of each pulse width modulation signal are distributed in a corresponding sub-time period, and then a plurality of paths of light-emitting diodes are sequentially lightened in a selected total time period in a time-sharing manner: the effective logic values, such as logic high 1, of the third pwm signal D3 are distributed in the first sub-period T1, the effective logic values, such as logic high 1, of the first pwm signal D1 are distributed in the second sub-period T2, and the effective logic values, such as logic high 1, of the second pwm signal D2 are distributed in the third sub-period T3. The multiple light-emitting diodes in the total time period are sequentially lightened in a time-sharing manner: the red led is turned on when the pwm signal D3 has an active logic value in the first sub-period T1, the green led is turned on when the pwm signal D1 has an active logic value in the second sub-period T2, and the blue led is turned on when the pwm signal D2 has an active logic value in the third sub-period T3. The result is that the red leds will not light up in T2-T3, and the green leds will not light up in T1 and T3, and the blue leds will not light up in T1 and T2. The desired result of the red and green and blue leds being time-shared lit in the monochrome mode is achieved. The effective logic value, e.g., the duty ratio of high level, of the third pwm signal D3 is adjusted in the first sub-period T1, the effective logic value, e.g., the duty ratio of high level, of the first pwm signal D1 is adjusted in the second sub-period T2, and the effective logic value, e.g., the duty ratio of high level, of the second pwm signal D2 is adjusted in the third sub-period T3. In addition to the time-sharing lighting sequence of red, green, blue, green.

Referring to fig. 11, a pin 401 of the display unit is coupled to a power input terminal VCC of a driving chip 500 and a constant current unit CS1 is disposed between the pin 402 of the display unit and a potential reference terminal GND. For example, the pin 401 is specifically coupled to the power supply input VCC by being connected to the pin 521 of the driver chip 500, and the pin 402 is specifically connected to the pin 522 of the driver chip 500. And further, there is a series connection between the pin 522 of the driving chip 500 and the potential reference terminal GND of the driving chip: a constant current unit CS1, a resistor r1, and a first link switch belonging to the multi-way switch S3. A multiswitch may also be generally referred to as a multiplexer or a multiswitch. The resistor r1 is an alternative embodiment of a voltage dividing load. The voltage dividing load can also adopt a common diode or a transistor with an on-resistance when being switched on, and can also adopt a series structure or a parallel structure of the common diode and the resistor and other loads with voltage dividing functions.

Referring to fig. 11, a pin 402 of the display unit is coupled to a power input terminal VCC of a driving chip 500 and a constant current unit CS1 is disposed between a pin 403 of the display unit and a potential reference terminal GND. For example, the pin 402 is specifically coupled to the power input VCC by being connected to the pin 522 of the driver chip 500, and the pin 403 is specifically connected to the pin 523 of the driver chip 500. And further, a pin 522 of the driver chip 500 is connected in series with a power input terminal VCC of the driver chip: a resistor r2 and a second link switch belonging to the multi-way switch S3. The constant current unit CS1 multiplexed by the red and green light emitting diodes can simplify the circuit. A constant current unit CS1 and a switch S1 are connected in series between the pin 523 of the driver chip 500 and the potential reference terminal GND of the driver chip.

Referring to fig. 11, a pin 402 of the display unit is coupled to a power input terminal VCC of the driving chip 500 and a constant current unit CS2 is disposed between the pin 404 of the display unit and a potential reference terminal GND. For example, pin 402 is specifically coupled to power supply input VCC by being connected to pin 522 of driver chip 500, and pin 404 is specifically connected to pin 524 of driver chip 500. And further, a constant current unit CS2 and a switch S2 are connected in series between the pin 524 of the driver chip 500 and the potential reference terminal GND of the driver chip.

Referring to fig. 11, a modified embodiment claims to shift the resistor r2 from the home position to between the anodes of the green and blue leds and the pin 402, or to shift the resistor r2 from the home position to between the pin 522 and the multiplexer S3 described above. Based on this improvement, the resistance r1 may be slightly reduced. The constant current unit CS1 with multiplexing of red and green leds in these embodiments can provide the first current value I1 and the third current value I3.

Referring to fig. 11, the multiway switch S3 is not activated in the white light mode. The first and second pulse width modulation signals respectively control switches S1 and S2, which are synchronous signals. The constant current unit CS1 provides the first current value I1 and the second current value I2 is synchronously provided by the constant current unit CS 2. The red, green and blue leds are illuminated simultaneously such that the sum of the first current value I1 flowing through the green led and the second current value 22 flowing through the blue led is equal to the third current value flowing through the red led.

Referring to fig. 11, the primary color leds are sequentially turned on in time division: when the third pwm signal D3 has an active logic value, e.g., a high level, the first link switch of the multi-way switch S3 is turned on, when the first pwm signal D1 has an active logic value, e.g., a logic high level, the corresponding switch S1 is turned on, and when the second pwm signal D2 has an active logic value, e.g., a logic high level, the corresponding switch S2 is turned on. Note that any of the switches S1 and S2 when turned on triggers the second link switch of the multi-way switch S3 to be turned on, i.e., the first and second pulse width modulation signals are also used to operate the second link switch of the multi-way switch S3 to be turned on or not. So that the multiple paths of light-emitting diodes in the total time period are sequentially lightened in a time-sharing manner: the red led is turned on when the pwm signal D3 has an active logic value in the first sub-period T1, the green led is turned on when the pwm signal D1 has an active logic value in the second sub-period T2, and the blue led is turned on when the pwm signal D2 has an active logic value in the third sub-period T3. The result is that the red LEDs will not light up in T2-T3, and the green LEDs will not light up in T1 and T3, and the blue LEDs will not light up in T1 and T2. The desired result of the red and green and blue leds being time-shared lit in the monochrome mode is achieved. The effective logic value, e.g., the duty ratio of high level, of the third pwm signal D3 is adjusted in the first sub-period T1, the effective logic value, e.g., the duty ratio of high level, of the first pwm signal D1 is adjusted in the second sub-period T2, and the effective logic value, e.g., the duty ratio of high level, of the second pwm signal D2 is adjusted in the third sub-period T3. Besides the time-sharing lighting sequence of red, green, blue, green, red, blue, green, blue, red, blue, green, blue and green, the order of the high level of the first to the third pulse width modulation signals is reasonably arranged as a countermeasure.

Referring to fig. 12, a pin 401 of the display unit is connected to a power input terminal VCC of a driving chip 500 and a constant current unit CS1 is provided between a pin 402 of the display unit and a potential reference terminal GND. For example, the pin 401 is specifically coupled to the power input VCC by being connected to the pin 531 of the driver chip 500, and the pin 402 is specifically connected to the pin 532 of the driver chip 500. And further, a voltage reference terminal GND of the driving chip is connected in series between the pin 532 of the driving chip 500 and the voltage reference terminal GND of the driving chip: a constant current unit CS1, a resistor r5, and a first link switch belonging to the multi-way switch S5. A first link switch belonging to the multi-way switch S4 is provided between the pin 531 and the power input VCC.

Referring to fig. 12, a pin 402 of the display unit is connected to a power input terminal VCC of a driving chip 500 and a constant current unit CS1 is provided between a pin 403 of the display unit and a potential reference terminal GND. For example, the pin 402 is specifically coupled to the power input VCC by being connected to a pin 532 of the driver chip 500, and the pin 403 is specifically connected to a pin 533 of the driver chip 500. And further, a pin 532 of the driver chip 500 is connected in series with a power input terminal VCC of the driver chip: a resistor r4 and a second link switch belonging to the multi-way switch S4. The constant current unit CS1 multiplexed by the red and green light emitting diodes can simplify the circuit. A pin 533 of the driving chip 500 is connected in series with a potential reference terminal GND of the driving chip: a constant current unit CS1, a resistor r5, and a second link switch belonging to the multi-way switch S5. The multiplexed constant current unit CS1 may provide the first current value I1 and the third current value I3.

Referring to fig. 12, a pin 402 of the display unit is connected to a power input terminal VCC of a driving chip 500 and a constant current unit CS2 is provided between a pin 404 of the display unit and a potential reference terminal GND. For example, the pin 402 is specifically coupled to the power supply input VCC by being connected to a pin 532 of the driver chip 500, and the pin 404 is specifically connected to a pin 534 of the driver chip 500. And further, a pin 534 of the driving chip 500 is connected in series with a potential reference terminal GND of the driving chip: a constant current unit CS2, a resistor r6, and a second link switch belonging to the multi-way switch S6. In an optional but not necessary embodiment, a further series connection may be connected between the pin 532 of the driver chip 500 and the potential reference terminal GND of the driver chip: a constant current unit CS2, a resistor r6, and a first link switch belonging to the multi-way switch S6. The multiplexed constant current unit CS2 may provide the second current value I2 and the third current value I3. R4 may be omitted provided that resistors r5 and r6 remain in some alternative embodiments. The improved embodiment claims to shift the resistor r4 from the home position to between the anodes of the green and blue leds and the pin 402, or to shift the resistor r4 from the home position to between the pin 532 and the previously described multi-way switch S5 or S6. The resistors are optional embodiments of the voltage dividing load, and the voltage dividing load may also adopt a common diode or a transistor having an on-resistance when being turned on, and the voltage dividing load may also adopt other loads having a voltage dividing function, such as a series structure or a parallel structure of a common diode and a resistor.

Referring to fig. 12, the primary color leds are sequentially turned on in time division: when the third pwm signal D3 has a high logic value, the first link switch of the multi-way switch S4 is turned on, and when the third pwm signal D3 has a high logic value, the first link switch of the multi-way switch S5 is turned on. When the first pwm signal D1 has a high logic value, the second link switch of the multi-way switch S4 is turned on, and when the first pwm signal D1 has a high logic value, the second link switch of the multi-way switch S5 is turned on. When the second pwm signal D2 has a high logic value, the second link switch of the multi-way switch S4 is turned on, and when the second pwm signal D2 has a high logic value, the second link switch of the multi-way switch S6 is turned on. So that the three-color light-emitting diodes in the total time period are sequentially lightened in a time-sharing manner: the red led is turned on when the pwm signal D3 has an active logic value in the first sub-period T1, the green led is turned on when the pwm signal D1 has an active logic value in the second sub-period T2, and the blue led is turned on when the pwm signal D2 has an active logic value in the third sub-period T3. The result is that the red LEDs will not light up in T2-T3, and the green LEDs will not light up in T1 and T3, and the blue LEDs will not light up in T1 and T2. The desired result of the red and green and blue leds being time-shared lit in the monochrome mode is achieved. The effective logic value, e.g., the duty ratio of high level, of the third pwm signal D3 is adjusted in the first sub-period T1, the effective logic value, e.g., the duty ratio of high level, of the first pwm signal D1 is adjusted in the second sub-period T2, and the effective logic value, e.g., the duty ratio of high level, of the second pwm signal D2 is adjusted in the third sub-period T3. Besides the time-sharing lighting sequence of red, green, blue, green, red, blue, green, blue, red, blue, green, blue and green, the order of the high level of the first to the third pulse width modulation signals is reasonably arranged as a countermeasure.

Referring to fig. 12, time-sharing lighting in the monochrome mode: the current flowing through the red light emitting diode is supplied from the constant current unit CS1 when the red light emitting diode is turned on. The current flowing through the green leds is also provided by the multiplexed constant current unit CS1 when the green leds are lit. The current flowing through the blue led is correspondingly provided by the constant current unit CS2 when the blue led is lit. That is, it is equivalent to the current flowing through the red light emitting diode, for example, the third current value I3, provided by the constant current unit CS1 when the red light emitting diode is turned on, which is not the only current supply manner.

Referring to fig. 12, an alternative embodiment of time-shared sequential lighting: when the third pwm signal D3 has a high logic value, the first link switch of the multi-way switch S4 is turned on, and when the third pwm signal D3 has a high logic value, the first link switch of the multi-way switch S6 is turned on. That is, the constant current unit CS2 provides the current flowing through the red light emitting diode, for example, the third current value I3, when the red light emitting diode is turned on. The example of fig. 8 in which the respective lighting periods of the rgb leds are overlapped is applied to fig. 12. If the first link switch of the multiplexer S4 is turned on, the multiplexer S5 may select to turn on the first or second link switch, while the multiplexer S6 may select to turn on the first or second link switch, such that during each cycle: the respective lighting periods of the red, green and blue light emitting diodes are set to be the same or different when the respective lighting periods of the red, green and blue light emitting diodes overlap. The lighting time of the red light emitting diode is determined by the duty ratio information carried by the gray scale data matched to the red color, that is, the duty ratio of the third pulse width modulation signal is determined. The lighting time of the green light emitting diode is determined by duty ratio information carried by the gray scale data matched to the green color, namely, the duty ratio of the first pulse width modulation signal is determined equivalently. The lighting time of the blue light emitting diode is determined by the duty ratio information carried by the gray scale data matched to the blue color, that is, the duty ratio of the second pulse width modulation signal is determined. The above are examples of alternatives in the color mode.

Referring to fig. 12, in an alternative embodiment, it may be claimed that the green light emitting diode is arranged in parallel with one first shunt branch and the blue light emitting diode is arranged in parallel with the first shunt branch, while the red light emitting diode is arranged in parallel with the other second shunt branch. In an alternative embodiment, the first shunting branch comprises for example a first link switch of the multi-way switch S5 to the sub-branch of the anode of the green led, the first shunting branch further comprises for example a first link switch of the multi-way switch S6 to the sub-branch of the anode of the blue led, and the second shunting branch comprises for example a second link switch of the multi-way switch S4 to the sub-branch of the resistor r4 to the cathode of the red led. The green and blue light emitting diodes are supplied with first and second current values in the form of pulse currents, respectively. In the color mode, when the first pwm signal D1 is at an active logic value, such as high level, the green led is in a turned-on state, such that the first current value I1 directly flows through the green led, when the first pwm signal D1 is at an inactive logic value, such as low level, the green led is turned off, the first shunting branch is turned on, such that the first current value I1 simultaneously flows through the first shunting branch, and the first current value I1 switches between the green led and the first shunting branch, such as the first current value either flows through the green led or flows through the first shunting branch. In the same way, in the color mode, when the second pulse width modulation signal D2 is at an active logic value, such as a high level, the blue led is in a lit state, so that the second current value I2 directly flows through the blue led, when the second pulse width modulation signal D2 is at an inactive logic value, such as a low level, the blue led is turned off, the first shunt branch is turned on, so that the second current value I2 simultaneously flows through the first shunt branch, and the second current value I2 switches between the blue led and the first shunt branch, i.e., the second current value either flows through the blue led or flows through the first shunt branch. In the same way, in the color mode, when the third pulse width modulation signal D3 has an active logic value such as high level, the red led is in a stage of being turned on so that the third current value I3 directly flows through the red led, when the third pulse width modulation signal D3 has an inactive logic value such as low level, the red led is turned off, the second shunt branch is turned on so that the third current value I3 simultaneously flows through the second shunt branch, the third current value I3 switches between the red led and the second shunt branch, i.e., the third current value either flows through the red led or flows through the second shunt branch, the third current value is equal to the total current value I1+ I2 obtained by adding the first current value and the second current value, and the third current value depends on the constant current units CS1 and CS 2.

Referring to fig. 12, an alternative embodiment of time-shared sequential lighting: when the third pwm signal D3 has a valid logic value, e.g., high level, the first link switch of the multi-way switch S4 is turned on, when the third pwm signal D3 has a valid logic value, e.g., high level, the first link switch of the multi-way switch S5 is turned on, and when the third pwm signal D3 has a valid logic value, e.g., high level, the first link switch of the multi-way switch S6 is turned on. When the red light emitting diode is lighted, the two constant current units provide current flowing through the red light emitting diode. In other words, the first current value I1 of the constant current unit CS1 and the second current value I2 of the constant current unit CS2 flow through the red light emitting diode together, in this embodiment, the total current of the first current value I1 flowing through the green light emitting diode and the second current value I2 flowing through the blue light emitting diode is equal to the third current value I3I 1+ I2 flowing through the red light emitting diode.

Referring to fig. 13, the four-pin type three-in-one lamp bead includes four pins. The pin type mentioned herein includes a pin of an in-line package structure or a pin of a surface mount package structure or a pin of a chip-on-board package structure, etc. In this embodiment, the anodes of the green-blue leds are coupled together, in other words, the anodes of the green-blue leds are all electrically connected to the same pin 402 but the cathodes of the green-blue leds are separated. The anode and cathode of the red light emitting diode R are electrically connected to the

pins

401 and 402, respectively, correspondingly. And the green light emitting diode G is electrically connected to the

pins

402 and 403 with its anode and cathode respectively. And the blue light emitting diode B is electrically connected to the

pins

402 and 404 at its anode and cathode, respectively. The packaging body PAK shown in the figure mainly functions to encapsulate the internal red, green and blue three-primary-color light emitting diodes in a plastic package manner for sealing, and the light-transmitting area LENS mainly functions to allow the light rays emitted by the three-primary-color light emitting diodes to be emitted from the area, and also belongs to the RGB-LED packaging type.

Referring to fig. 14, the driving chip and the light emitting diode are integrated into the same package. The driving chip 500 and the three primary color display unit 400 driven thereby are integrated into the same package. The package PAK mainly functions to encapsulate the rgb leds and the driving chip therein, and the transparent region LENS mainly functions to allow the light emitted from the rgb leds to be emitted from the transparent region. The pins of the package are omitted from the figure.

Referring to fig. 15, the core components of a three-primary color display unit or a three-primary color display circuit or a three-primary color pixel circuit mainly include red and green light emitting diodes and blue light emitting diodes: with green and blue light emitting diodes arranged in parallel connection, and a red light emitting diode arranged in series with the parallel arrangement with both green and blue light emitting diodes. An anode of a red light emitting diode R is provided in the display unit while being coupled to a cathode of a green light emitting diode G and a cathode of a blue light emitting diode B. The cathode of the red led R is coupled to terminal or pin 604 alone. The anode of green led G is coupled to terminal or pin 602 and the anode of blue led B is arranged to be coupled to terminal or pin 601. It is further provided that the cathodes of the green leds G and the cathodes of the blue leds B are both coupled to a common terminal or pin 603. The three-primary color display unit 600 may further include electronic components such as resistors, etc. that may be used, in addition to the light emitting diodes of the primary colors.

Referring to fig. 15, pure white light or full color can be provided by the three primary color display unit of the present example based on solving the doubtful and troublesome problems faced by the conventional common-anode or common-cathode three-in-one lamp bead or six-pin three-in-one lamp bead. The current flowing through the red led R is defined to have the third current value I3, the current flowing through the green led G is defined to have the first current value I1, and the current flowing through the blue led G is defined to have the second current value I2. In the white light mode, the red, green and blue primary color light emitting diodes are simultaneously lighted, or the red, green and blue primary color light emitting diodes are considered to be simultaneously turned off or extinguished. The red light-emitting diode is driven to be turned on when the green-blue primary light-emitting diodes are powered on simultaneously, or the red light-emitting diode is driven to be turned off once the green-blue primary light-emitting diodes are turned off simultaneously. The present example requires that the sum of the first current I1 flowing through the green LED G and the second current I2 flowing through the blue LED B is equal to the third current I3 flowing through the red LED R. The mathematical formula is represented as I1+ I2 ═ I3. The leg 603 coupled to the anode of the red led and to the cathode of the green-blue led at this stage is electrically floating and current neither flows into nor out of the leg. As a preferred embodiment for improving the white light purity, the third current value I3, the first current value I1 and the second current value I2 have a predetermined proportional relationship in the white light mode. For example, it is claimed that the predetermined ratio relationship I3: I1: I2 is set to 8:5:3 or 8:4:4, and it is noted that the specific ratio used for illustration is only an example and not a limitation, for example, the alternative ratios of 8.1:5:3.1 or 7.8:3.9:3.9 are desirable alternatives and can also achieve the purpose of improving the white light purity.

Referring to fig. 15, the rgb leds are time-shared and constant-current lit in the monochrome mode, and it is required that the respective lighting periods of the red, green, and blue leds do not overlap each other. The first and second current values and the third current value are provided, for example, in the form of a pulse current, which means that the first and second current values and the third current value are periodically repeated currents that do not continuously exist. In an alternative example, it is assumed that in any one common period, the red led R is first driven to light by the full-amplitude third current value I3 and then the red led R is extinguished by removing the third current value I3, then the green led G is driven to light by the full-amplitude first current value I1 and then the green led G is extinguished by removing the first current value I1, and then the blue led B is driven to light by the full-amplitude second current value I2 and then the blue led B is extinguished by removing the second current value I2. The lighting time periods of the primary color light emitting diodes are not overlapped, and the method is a typical example of time-sharing lighting of the three primary color light emitting diodes.

Referring to fig. 15, the rgb leds are simultaneously constant-current-lit in the white light mode, and it is required that the respective lighting periods of the red and green and blue leds coincide with each other. The first current value, the second current value and the third current value are provided in the form of pulse current, for example, and the pulse current means that the first current value, the second current value and the third current value are periodically repeated and the magnitude of the current is adjustable. In an alternative example, it is assumed that the green led G is driven to light with the full-amplitude first current value I1 and the blue led B is driven to light with the full-amplitude second current value I2 in synchronization in any one common period, and then the green led G is turned off by removing the first current value I1 and the blue led B is turned off by removing the second current value I2 in synchronization. Alternatively, assuming that the green led G is driven to light by the full-amplitude first current value I1 and the blue led B is driven to light by the full-amplitude second current value I2 in any one common period, the green led G and the blue led B are kept on continuously throughout the period, i.e. the green led G is lit without removing the first current value I1 and the blue led B is lit without removing the second current value I2. Since the first current value I1 and the second current value I2 are combined to flow through the red light emitting diode, the third current value flowing through the red light emitting diode follows the first current value I1 and the second current value I2 as long as the green light emitting diode G and the blue light emitting diode B are simultaneously turned on. It is satisfied that the sum of the first current value I1 flowing through the green led G and the second current value I2 flowing through the blue led B is equal to the third current value I3 flowing through the red led R. This embodiment realizes that the respective lighting periods of the three primary color light emitting diodes coincide with each other, which is a typical example of the simultaneous lighting or extinguishing of the three primary color light emitting diodes.

Referring to fig. 15, in the color mode, the respective constant current lighting periods of the rgb leds are overlapped, and the respective lighting periods of the rgb leds are set to be the same or different. A first current value I1 is provided in the form of a pulsed current and a second current value I2 is provided in the form of a pulsed current. During each cycle period: the duty ratio characterized by the gray scale data matched to green determines the lighting time period that the first current value I1 is loaded on the green light emitting diode, the duty ratio characterized by the gray scale data matched to blue determines the lighting time period that the second current value I2 is loaded on the blue light emitting diode, and the duty ratio characterized by the gray scale data matched to red determines the lighting time period that the total current containing both the first and second current values I1 and I2 is loaded on the red light emitting diode. For example, at each cycle: the method comprises the steps of driving a green light emitting diode G to light by using a first current value I1 with a full amplitude value, driving a blue light emitting diode B to light by using a second current value I2 with a full amplitude value synchronously, driving a red light emitting diode R to light by using the total current synchronously, removing the first current value I1 to extinguish the green light emitting diode G after the lighting time length determined by green matching gray scale data is finished, removing the second current value I2 to extinguish the blue light emitting diode B after the lighting time length determined by blue matching gray scale data is finished, and removing the total current to extinguish the red light emitting diode R after the lighting time length determined by red matching gray scale data is finished. This example applies to fig. 4.

Referring to fig. 16, the driving chip 500 decodes the gray scale data to obtain the gray scale data, and the first pulse width modulation module of the pulse width modulation module PWM forms the first pulse width modulation signal D1 corresponding to the first light emitting diode G according to the gray scale data allocated to the first light emitting diode R. The second PWM module generates a second PWM signal D2 corresponding to the second LED B according to the gray scale data distributed to the second LED B. The pulse width modulation signal corresponding to each light emitting diode may be formed according to the gray data assigned to each light emitting diode. The gray scale data assigned to the first way light emitting diode R and the gray scale data assigned to the second way light emitting diode B are allowed to be the same value in the white light mode, provided that they are equal to the gray scale data defined for the white light. For example, if the duty ratio represented by the gray scale data matched for white light is 95%, the duty ratios of the first and second pulse width modulation signals are determined to be 95%. In the same sense, the duty cycles of the first and second pulse width modulated signals are determined to be 100% provided that the duty cycle characterized by the white light matched gray scale data is 100%. And so on, in the white light mode, it can be considered that the duty ratios of the first and second pulse width modulation signals are confirmed and adjusted by the gray scale data matched to the white light. The pin 603 floats in the white light mode.

Referring to fig. 16, a first light emitting diode G is connected in series with the constant current unit CS1, and it is noted that the constant current unit CS1 generating a constant current is controlled by the first pulse width modulation signal D1. The first pwm signal D1 determines the constant current lighting time of the first led in the period of the first pwm signal D1. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the first pwm signal D1 has a high logic level, the constant current is applied to the first led G, and when the current is off, for example, the first pwm signal D1 has a low logic level, the constant current is disconnected from the first led G. Pin 602 of trinity lamp pearl is coupled to driver chip 500's pin 542, is provided with constant current unit CS1 between driver chip 500's pin 542 and driver chip's power input VCC. The constant current unit CS1 may provide the first current value I1.

Referring to fig. 16, the second led B and the constant current unit CS2 are arranged in series, and it is noted that the constant current unit CS2 generating a constant current is controlled by the second pwm signal D2. The second pwm signal D2 determines the constant current lighting time of the second led in the period of the second pwm signal D2. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the second pwm signal D2 has high logic level, the constant current is applied to the second led B, and when the current is off, for example, the second pwm signal D2 has low logic level, the constant current is disconnected from the second led B. Pin 601 of trinity full-color lamp pearl couples to driver chip 500's pin 541, is provided with constant current unit CS2 between driver chip 500's pin 541 and driver chip's power input VCC. The constant current unit CS2 may provide the second current value I2.

Referring to fig. 16, a simple scheme is that each light emitting diode and one constant current unit are coupled in series between a power input terminal and a potential reference terminal. In the figure, the light emitting diodes G and R and the constant current unit CS1 are connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diodes B and R and the constant current unit CS2 are connected in series between the power input terminal VCC and the potential reference terminal GND. The anode of the led G, i.e., the pin 602, is coupled to the power input VCC at the pin 542 of the driver chip 500, so that the input voltage or the green-red led is directly utilized to supply power. The anode of the led B, i.e., the pin 601, is coupled to the power input terminal VCC at the pin 541 of the driving chip 500, so that the input voltage or the power supply voltage at the power input terminal VCC is directly utilized to supply power to the blue-red led. The pin 604 of the three-in-one full-color lamp bead is coupled to the pin 544 of the driving chip 500, and the pin 544 of the driving chip 500 is coupled to the potential reference terminal GND.

Referring to fig. 16, the positions of the light emitting diode and the constant current unit are examples of the source current. Besides directly utilizing the input voltage of the power input end VCC or the power supply source to supply power for the light emitting diodes, the divided voltage of the input voltage at the power input end VCC can also supply power for each path of light emitting diodes. In an alternative example, the led string group and the corresponding one of the constant current units are coupled in series between a divided voltage of the input voltage and the potential reference terminal. In another example, a stable voltage obtained by performing a linear or switch type or charge pump type voltage conversion on the input voltage provided at the power input terminal VCC may be used to supply power to each of the light emitting diodes, and the light emitting diode serial group and the corresponding one of the constant current units are coupled in series between the stable voltage obtained by the voltage conversion and the potential reference terminal.

Referring to fig. 16, the green light emitting diode G is driven to light up with the full-amplitude first current value I1 and the blue light emitting diode B is driven to light up with the full-amplitude second current value I2 in any one common period TPWM < N >, where N is a natural number. The constant current unit CS1 generating a constant current, i.e., a first current value I1, is controlled by the first pwm signal D1, and the constant current unit CS2 generating a constant current, i.e., a second current value I2, is controlled by the second pwm signal D2. The first pulse width modulation signal D1 and the second pulse width modulation signal D2 are synchronous signals and simultaneously have a logic high level and a logic low level in a common period, and the first pulse width modulation signal and the second pulse width modulation signal represent duty ratio information carried by gray scale data suitable for white light. It is meant that the driving chip can determine the duty ratio of the first and second pwm signals according to the gray scale data suitable for white light. For example, assuming that the gray scale data matched to the white light determines that the duty ratio of the first and second pulse width modulation signals is 85%, the average current flowing through the green light emitting diode G in a period is the first current value I1 multiplied by 85%, and the average current flowing through the blue light emitting diode B in a period is the second current value I2 multiplied by 85%. It has been described above that the third current value I3 flowing through the red led varies synchronously with the first current value I1 and the second current value I2, and the average current flowing through the red led R in the cycle is the sum of the first current value I1 and the second current value I2 multiplied by 85%. In the white light mode, no pwm signal is used to directly control the on/off of the red led R, and in fact, the red led R is only indirectly controlled by the first and second pwm signals. Assuming that the end of the previous common period TPWM < N > is followed by the next adjacent common period TPWM < N +1>, the duty ratios of the first and second pwm signals in any one common period may be set to be identical, and in contrast, the duty ratios of the first and second pwm signals in the previous common period and the duty ratios of the first and second pwm signals in the next common period may be set to be different as long as the duty ratio information carried by the gray scale data matching the white light is changed.

Referring to fig. 17, the

pins

601 and 602 of the display unit are connected to the power input terminal of the driving chip 500, and the constant current units CS1 and CS2 are provided between the pin 603 of the display unit and the power input terminal VCC. For example, the pin 601 is specifically coupled to the power supply input terminal VCC by being connected to the pin 541 of the driver chip 500, and for example, the pin 602 is specifically coupled to the power supply input terminal VCC by being connected to the pin 542 of the driver chip 500, and the pin 603 is specifically connected to the pin 543 of the driver chip 500. And further, a pin 543 of the driving chip 500 is connected in series with the power input VCC of the driving chip: a constant current unit CS1 and an adjustable shunt reference source Z3 and a second link switch belonging to a multi-way switch S04. And further, there are connected in series between the pin 542 of the driver chip 500 and the power input terminal VCC of the driver chip: a constant current unit CS1, and a first link switch belonging to the multi-way switch S04. In addition, a pin 543 of the driving chip 500 is connected in series with the power input VCC: a constant current unit CS2, an adjustable shunt reference source Z3 and a second link switch belonging to a multi-way switch S05. The pin 541 of the driving chip 500 and the power input terminal VCC are connected in series: a constant current unit CS2, and a first link switch belonging to the multi-way switch S05. Furthermore, a first link switch belonging to the multi-way switch S03 is provided between the pin 544 of the driver chip 500 and the potential reference terminal GND, and a first switch is connected in series between the potential reference terminal GND and the pin 543: an adjustable shunt reference source Z4 and a second link switch belonging to the multi-way switch S06. The pins 604 of the display unit are coupled to the pins 544 of the driver chip.

Referring to fig. 17, an adjustable shunt reference source Z4 is connected in parallel with the red led. The multi-way switch S06 is controlled by the third pwm signal D3. The cathode of the red led that is turned on when the third pwm signal D3 has a valid logic value is connected to the potential reference terminal, and the total current obtained by adding the first current value and the second current value flows through the red led. Otherwise, when the third pwm signal D3 has an invalid logic value, the red led is turned off, the total current obtained by adding the first and second current values flows through the adjustable shunt reference source Z4, the anode a of the adjustable shunt reference source Z4 is connected to the potential reference terminal and the cathode K of the adjustable shunt reference source Z4 is coupled to the respective cathodes of the green and blue leds, and the cathode K of the adjustable shunt reference source Z4 is coupled to the anode of the red led. A resistive voltage divider, not shown, may be connected between the cathode K and the anode a of the adjustable shunt reference source Z4, the resistive voltage divider comprising two resistors and a voltage dividing node at the interconnection of the two resistors may be coupled to the reference terminal REF of the adjustable shunt reference source Z4.

Referring to fig. 17, an adjustable shunt reference source Z3 is connected in parallel with the green led. The multi-way switch S04 is controlled by the first pwm signal D1. When the first pwm signal D1 has a valid logic value, the anode of the lit green led is connected to the constant current unit CS1, and the first link switch of the multi-way switch S04 is turned on to let the first current value flow through the green led. On the contrary, when the first pulse-width modulation signal D1 has a non-valid logic value, the green led is turned off, the second link switch of the multi-way switch S04 is turned on, and the first current value flows through the adjustable shunt reference source Z3, at this time, the cathode K of the adjustable shunt reference source Z3 is connected to the constant current unit CS1 and the anode a of the adjustable shunt reference source Z3 and coupled to the anode of the red led, the anode a of the adjustable shunt reference source Z3 is coupled to the cathode K of the adjustable shunt reference source Z4, and it is satisfied that the anode a of the adjustable shunt reference source Z3 is coupled to the cathodes of both the green and blue leds. An additional unillustrated resistor divider may be connected between the cathode K and the anode A of the adjustable shunt reference source Z3, the resistor divider comprising two resistors and a voltage dividing node at the interconnection of the two resistors may be coupled to the reference terminal REF of the adjustable shunt reference source Z3.

Referring to fig. 17, an adjustable shunt reference source Z3 is connected in parallel with the blue led. The multi-way switch S05 is controlled by the second pulse-width modulation signal D2. The anode of the blue LED that is lighted when the second PWM signal D2 has a valid logic value is connected to the constant current unit CS2, and the first link switch of the multi-way switch S05 is turned on to let the second current value flow through the blue LED. Otherwise, when the second channel of pwm signal D2 has an invalid logic value, the blue led is turned off, and the second link switch of the multi-way switch S05 is turned on to let the second current value flow through the adjustable shunt reference source Z3, at this time, the cathode K of the adjustable shunt reference source Z3 is connected to the constant current unit CS2 and the anode a of the adjustable shunt reference source Z3 is coupled to the anode of the red led, and the anode a of the adjustable shunt reference source Z3 is coupled to the cathode K of the adjustable shunt reference source Z4. It is noted that if both the blue and green leds are turned off, the first current value and the second current value simultaneously flow through the adjustable shunt reference source Z3, causing the second link switch of the multi-way switch S04 to be turned on and the second link switch of the multi-way switch S05 to be turned on.

Referring to fig. 17, the rgb leds are simultaneously turned on at a constant current in the white light mode, so that the respective turn-on periods of the red, green, and blue leds coincide with each other. For example, if the first link switch of the multi-way switch S04 is turned on and the first link switch of the multi-way switch S05 is turned on and the first link switch of the multi-way switch S06 is turned on, the pin 603 is electrically floated, so that the sum of the first current value I1 flowing through the green led and the second current value I2 flowing through the blue led is equal to the third current value flowing through the red led.

Referring to fig. 17, the primary color leds are sequentially turned on in time division: when the third pwm signal D3 has a valid logic value, if it is high, the first link switch of the multi-way switch S06 is turned on, and when the third pwm signal D3 has a valid logic value, the second link switch of the multi-way switch S04 and/or S05 is turned on. When the first pwm signal D1 has a high logic value, the first link switch of the multi-way switch S04 is turned on, and when the first pwm signal D1 has a high logic value, the second link switch of the multi-way switch S06 is turned on. When the second pwm signal D2 has a high logic value, the first link switch of the multi-way switch S05 is turned on, and when the second pwm signal D2 has a high logic value, the second link switch of the multi-way switch S06 is turned on. So that the three-color light-emitting diodes in a certain total time period are sequentially lightened in a time-sharing manner: the red led is turned on when the pwm signal D3 has an active logic value in the first sub-period T1, the green led is turned on when the pwm signal D1 has an active logic value in the second sub-period T2, and the blue led is turned on when the pwm signal D2 has an active logic value in the third sub-period T3. The result is that the red LEDs will not light up in T2-T3, and the green LEDs will not light up in T1 and T3, and the blue LEDs will not light up in T1 and T2. The desired result of the red and green and blue leds being time-shared lit in the monochrome mode is achieved. The effective logic value, e.g., the duty ratio of high level, of the third pwm signal D3 is adjusted in the first sub-period T1, the effective logic value, e.g., the duty ratio of high level, of the first pwm signal D1 is adjusted in the second sub-period T2, and the effective logic value, e.g., the duty ratio of high level, of the second pwm signal D2 is adjusted in the third sub-period T3. Besides the time-sharing lighting sequence of red, green, blue, green, red, blue, green, blue, red, blue, green, blue and green, the order of the high level of the first to the third pulse width modulation signals is reasonably arranged as a countermeasure.

Referring to fig. 17, in an alternative embodiment, it may be claimed that the green leds are arranged in parallel with one first shunt branch and the blue leds are arranged in parallel with the first shunt branch, while the red leds are arranged in parallel with the other second shunt branch. In an alternative embodiment, the first tap branch may employ, for example, the adjustable tap reference source Z3 described above, and the second tap branch may employ, for example, the adjustable tap reference source Z4 described above. In an alternative embodiment, the first shunt leg uses a resistor and the second shunt leg uses another resistor, such as replacing the adjustable shunt reference source Z3 described above with one resistor and the adjustable shunt reference source Z4 with another resistor. Even the first shunt branch may use a conventional diode in forward conduction while the second shunt branch uses another conventional diode, for example, replacing the aforementioned adjustable shunt reference source Z3 with a conventional diode and the adjustable shunt reference source Z4 with a conventional diode. In the color mode, the first current value I1 flows directly through the green light-emitting diode during the period when the green light-emitting diode is turned off and during the period when the green light-emitting diode is turned on, so that the first current value I1 switches between the green light-emitting diode and the first current-dividing branch, and the first current value I1 flows through either the green light-emitting diode or the first current-dividing branch, i.e., so-called switching of the first current value I1 is achieved. According to the same principle, in the same color mode, the first shunt branch is also simultaneously turned on in the phase when the blue light emitting diode is turned off, and the second current value I2 directly flows through the blue light emitting diode in the phase when the blue light emitting diode is turned on, so that the second current value I2 is switched to flow between the blue light emitting diode and the first shunt branch, and the second current value I2 flows through either the blue light emitting diode or the first shunt branch, that is, so-called switching flow of the second current value I2 is realized. In the same way, in the same manner, during the color mode, the second shunt branch is also switched on simultaneously during the phase when the red light-emitting diode is switched off, and the total current value resulting from the addition of the first and second current values during the phase when the red light-emitting diode is lit is passed directly through the red light-emitting diode, so that as a result the total current value resulting from the addition of the first and second current values, I1+ I2 flowing either through the red light-emitting diode or through the second shunt branch, i.e. the so-called switched flow of the total current value I1+ I2 resulting from the addition of the first and second current values, is switched to flow between the red light-emitting diode and the second shunt branch.

Referring to fig. 17, in conjunction with fig. 8, the red led is turned on during the high level period of the third pwm signal D3 and the green led is turned on during the high level period of the first pwm signal D1, and similarly, the blue led is turned on during the high level period of the second pwm signal D2. The respective lighting periods of the red, green and blue light emitting diodes are set to overlap in each common cycle period, that is, the high level periods corresponding to the three pulse width modulation signals overlap with each other, and the respective lighting periods of the red, green and blue light emitting diodes may also be set to be the same or different in each cycle period. And the respective lighting time duration of the red, green and blue three primary color light emitting diodes is determined by the respective duty ratio of the first to third pulse width modulation signals D1 to D3. The special case of the color mode is that the duty cycles of the first to third pwm signals D1 to D3 are identical, and then since the rgb leds are simultaneously turned on and their respective turn-on periods are coincident, and the respective turn-on periods of the red, green, and blue leds are identical, the sum of the first current value flowing through the green led and the second current value flowing through the blue led is equal to the current flowing through the red led, and white light may be generated.

Referring to fig. 18, the cathodes of both the first and second leds G, B are coupled to each other and connected at the same common pin 603, and the anodes of the third leds R are also coupled to their cathodes and connected at the same common pin 603. The pin 603 is connected to the pin 553 of the driving chip 500, and a switch S10 is provided between the potential reference terminal GND of the driving chip and the pin 553 of the driving chip.

Referring to fig. 18, a first light emitting diode G is connected in series with the constant current unit CS1, and it is noted that the constant current unit CS1 generating a constant current is controlled by a first pulse width modulation signal D1. The first pwm signal D1 determines the constant current lighting time of the first led in the period of the first pwm signal D1. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the first pwm signal D1 has a high logic level, the constant current is applied to the first led G, and when the current is off, for example, the first pwm signal D1 has a low logic level, the constant current is disconnected from the first led G. Pin 602 of trinity lamp pearl is coupled to drive chip 500's pin 552, is provided with constant current unit CS1 between drive chip 500's pin 552 and drive chip's power input VCC. The constant current unit CS1 provides a first current value I1. Note that the first pwm signal D1 is also used to control the switch S10. The first pwm signal D1 has a high logic level and the switch S10 is turned on, and the switch S10 is turned off during a normal period.

Referring to fig. 18, the second led B is provided in series with the constant current unit CS2, and it is noted that the constant current unit CS2 generating a constant current is controlled by the second pwm signal D2. The second pwm signal D2 determines the constant current lighting time of the second led in the period of the second pwm signal D2. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the second pwm signal D2 has high logic level, the constant current is applied to the second led B, and when the current is off, for example, the second pwm signal D2 has low logic level, the constant current is disconnected from the second led B. Pin 601 of trinity full-color lamp pearl is connected to drive chip 500's pin 551, is provided with constant current unit CS2 between drive chip 500's pin 551 and drive chip's power input VCC. The constant current unit CS2 provides the second current value I2. Note that the second pulse width modulation signal D2 is also used to control the switch S10. The second pulse width modulation signal D2 has a high logic level and the switch S10 is turned on, and the switch S10 is in an off state during a normal period.

Referring to fig. 18, it is assumed that the third light emitting diode R and the constant current unit CS3 are connected in series, and it is noted that the constant current unit CS3 generating a constant current is controlled by the third pulse width modulation signal D3. The third pwm signal D3 determines the constant current lighting time of the third led in the cycle of the second pwm signal D3. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the third pwm signal D3 has a high logic level, the constant current is applied to the third led R, and when the current is off, for example, the third pwm signal D3 has a low logic level, the constant current is disconnected from the third led R. Pin 603 of trinity full-color lamp pearl is connected to driver chip 500's pin 553, is provided with constant current unit CS3 between driver chip 500's pin 553 and driver chip's power input VCC. The constant current unit CS3 provides the third current value I3.

Referring to fig. 18, a simple scheme is that each light emitting diode and one constant current unit are coupled in series between a power input terminal and a potential reference terminal. The light emitting diode R and the constant current unit CS3 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diode B and the constant current unit CS2 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diode G and the constant current unit CS1 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND. The anode of the led R, i.e., the pin 603, is coupled to the power input VCC at the pin 553 of the driver chip 500, thereby indirectly utilizing the input voltage or power supply voltage at the power input VCC for the red-colored led. The anode of the led G, i.e., the pin 602, is coupled to the power input VCC at the pin 552 of the driver chip 500, thereby indirectly utilizing the input voltage or green led power supply voltage at the power input VCC. The anode of the led B, i.e., the pin 601, is coupled to the power input VCC at the pin 551 of the driver chip 500, so that the input voltage or the power supply voltage at the power input VCC is indirectly utilized to supply power to the blue led. A shunt module, which is not shown in the figure, can also be connected in series between the supply input VCC and the potential reference GND. The input voltage at the power input terminal VCC is a power supply for driving other functional modules in the chip, in addition to being a power supply for the light source. The stable voltage obtained by performing linear or switch type or charge pump type voltage conversion on the input voltage at the power input end can also supply power to each light emitting diode.

Referring to fig. 18, the red and green and blue leds are time-divisionally lit in the monochrome mode. The red led is illuminated by coupling pin 603 to the power input VCC to provide a supply voltage to the red led and a current through the red led from pin 603. In the same way, the green led is illuminated by coupling pin 602 to the power input VCC to switch on or input the power supply voltage to the green led and provide current through the green led from pin 602. In the same way, the blue led is coupled to the power input VCC by the pin 601 when it is turned on, so as to switch on or input the power supply voltage to the blue led and provide the current flowing through the blue led from the pin 601. The current flowing through the green or blue leds during the time-shared lighting phase flows from pin 603, along pin 553 and on to potential reference GND along switch S10, which is controlled to be on. While the current flowing through the red led in the time-division lighting phase flows from the pin 604, and flows along the pin 604 and the pin 554 to the potential reference terminal GND.

Referring to fig. 18, in the white light mode, a power supply voltage is input from a pin 601 and a first current value flowing through the blue led is provided from the pin 601, and a power supply voltage is input from a pin 602 and a second current value flowing through the green led is provided from the pin 602, respectively, so that a third current value flowing through the red led is equal to the sum of the first current value and the second current value. The pin 603 is required to float in the white light mode.

Referring to fig. 18, the foregoing total period in which the respective pulse width modulation signals D1 and D2 and D3 appear at the high level is divided into the foregoing sub-periods T1-T3. The effective logic value distribution of each pulse width modulation signal is in a corresponding sub-time period, and then multiple paths of light emitting diodes are sequentially lightened in a time-sharing manner in a cycle period TPWM: the effective logic values, such as logic high, of the third pwm signal D3 are distributed in the first sub-period T1, the effective logic values, such as logic high, of the first pwm signal D1 are distributed in the second sub-period T2, and the effective logic values, such as logic high, of the second pwm signal D2 are distributed in the third sub-period T3. In the total time period, the multiple paths of light-emitting diodes are sequentially lightened in a time-sharing manner: the red led is turned on when the pwm signal D3 has an active logic value in the first sub-period T1, the green led is turned on when the pwm signal D1 has an active logic value in the second sub-period T2, and the blue led is turned on when the pwm signal D2 has an active logic value in the third sub-period T3. The result is that the red leds will not light up in T2-T3, and the green leds will not light up in T1 and T3, and the blue leds will not light up in T1 and T2. The desired result of the red and green and blue leds being time-shared lit in the monochrome mode is achieved. The effective logic value, e.g., the duty ratio of high level, of the third pwm signal D3 is adjusted in the first sub-period T1, the effective logic value, e.g., the duty ratio of high level, of the first pwm signal D1 is adjusted in the second sub-period T2, and the effective logic value, e.g., the duty ratio of high level, of the second pwm signal D2 is adjusted in the third sub-period T3. Besides the time-sharing lighting sequence of red, green, blue, green, red, blue, green, blue, red, blue, green, blue and green, the order of the high level of the first to the third pulse width modulation signals is reasonably arranged as a countermeasure.

Referring to fig. 19, the cathodes of both the first and second leds G, B are coupled to each other and connected at the same common pin 603, and the anodes of the third leds R are also coupled to their cathodes and connected at the same common pin 603. The pin 603 is connected to the pin 563 of the driver chip 500, and a switch S10 is provided between the potential reference terminal GND of the driver chip and the pin 563 of the driver chip.

Referring to fig. 19, a first light emitting diode G is connected in series with the constant current unit CS1, and it is noted that the constant current unit CS1 generating a constant current is controlled by a first pulse width modulation signal D1. The first pwm signal D1 determines the constant current lighting time of the first led in the period of the first pwm signal D1. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the first pwm signal D1 has a high logic level, the constant current is applied to the first led G, and when the current is off, for example, the first pwm signal D1 has a low logic level, the constant current is disconnected from the first led G. Pin 602 of trinity lamp pearl couples to driver chip 500's pin 562, and it has to establish ties in proper order between driver chip 500's pin 562 and driver chip's power input VCC: a constant current unit CS1, a switch S8, and a resistor r 8. The first pulse width modulation signal D1 is further used for controlling the switch S10. The constant current unit CS1 may provide the first current value I1. When the first pwm signal D1 is high, the switches S10 and S8 are turned on, and the switches S10 and S8 are turned off in normal time.

Referring to fig. 19, the second led B is provided in series with the constant current unit CS2, and it is noted that the constant current unit CS2 generating a constant current is controlled by the second pwm signal D2. The second pwm signal D2 determines the constant current lighting time of the second led in the period of the second pwm signal D2. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the second pwm signal D2 has high logic level, the constant current is applied to the second led B, and when the current is off, for example, the second pwm signal D2 has low logic level, the constant current is disconnected from the second led B. Pin 561 of driver chip 500 is connected to pin 601 of trinity full-color lamp pearl, and it has to establish ties in proper order between pin 561 of driver chip 500 and driver chip's the power input VCC: a constant current unit CS2, a switch S9, and a resistor r 9. The second pulse width modulation signal D2 is also used to control the switch S10. The constant current unit CS2 may provide the second current value I2. When the second pwm signal D2 is at high level, the switches S10 and S9 are turned on, and the switches S10 and S9 are turned off in the normal period.

Referring to fig. 19, it is assumed that the third light emitting diode R and the constant current unit CS3 are connected in series, and it is noted that the constant current unit CS3 generating a constant current is controlled by the third pulse width modulation signal D3. The third pwm signal D3 determines the constant current lighting time of the third led in the cycle of the second pwm signal D3. A constant current of full amplitude is applied to the light source in a repetitive pulse train that is on or off: when the current is on, for example, the third pwm signal D3 has a high logic level, the constant current is applied to the third led R, and when the current is off, for example, the third pwm signal D3 has a low logic level, the constant current is disconnected from the third led R. Pin 563 to driver chip 500 is connected to pin 603 of trinity full-color lamp pearl, and it has in series in proper order between driver chip 500's pin 563 and driver chip's power input VCC: a constant current unit CS3, a switch S7, and a resistor r 7. The third pwm signal D3 is also used to control the switch S7. The constant current unit CS3 may provide the third current value I3. Note that the third pwm signal D3 is high, and the switch S7 is turned on. The regular period switches S10 and S7 are turned off.

Referring to fig. 19, a simple scheme is that each light emitting diode and one constant current unit are coupled in series between a power input terminal and a potential reference terminal. The light emitting diode R and the constant current unit CS3 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diode B and the constant current unit CS2 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND, and the light emitting diode G and the constant current unit CS1 are shown to be connected in series between the power input terminal VCC and the potential reference terminal GND. The anode of the led R, i.e., pin 603, is coupled to the power input VCC at pin 563 of the driver chip 500, thereby indirectly utilizing the input voltage or red power supply voltage at the power input VCC to supply power to the leds. The anode of the led G, i.e., the pin 602, is coupled to the power input VCC at the pin 562 of the driver chip 500, so that the green led is indirectly powered by the input voltage or the power supply voltage at the power input VCC. The anode of the led B, i.e., the pin 601, is coupled to the power input VCC at the pin 561 of the driving chip 500, so as to indirectly use the input voltage or the power supply voltage at the power input VCC to supply power to the blue led. A shunt module, which is not shown in the figure, can also be connected in series between the supply input VCC and the potential reference GND. The input voltage at the power input terminal VCC is a power supply for driving other functional modules in the chip, in addition to being a power supply for the light source. The stable voltage obtained by performing linear or switch type or charge pump type voltage conversion on the input voltage at the power input end can also supply power to each light emitting diode.

Referring to fig. 19, the red and green and blue leds are time-divisionally lit in the monochrome mode. The red led is illuminated by coupling pin 603 to the power input VCC to provide a supply voltage to the red led and a current through the red led from pin 603. In the same way, the green led is illuminated by coupling pin 602 to the power input VCC to switch on or input the power supply voltage to the green led and provide current through the green led from pin 602. In the same way, the blue led is coupled to the power input VCC by the pin 601 when it is turned on, so as to switch on or input the power supply voltage to the blue led and provide the current flowing through the blue led from the pin 601. The current flowing through the green or blue leds during the time-division illuminated phase flows from pin 603, along pin 563 and on to potential reference GND along switch S10 which is controlled to be on. While the current flowing through the red led in the time-division lighting phase flows from the pin 604, and flows along the pin 604 and the pin 564 to the potential reference terminal GND.

Referring to fig. 19, in the white light mode, a power supply voltage is input from a pin 601 and a first current value flowing through the blue led is provided from the pin 601, and a power supply voltage is input from a pin 602 and a second current value flowing through the green led is provided from the pin 602, respectively, so that a third current value flowing through the red led is equal to the sum of the first current value and the second current value. The pin 603 is required to float in the white light mode.

Referring to fig. 19, the foregoing total period in which the respective pulse width modulation signals D1 and D2 and D3 appear at the high level is divided into the foregoing sub-periods T1-T3. The effective logic value distribution of each pulse width modulation signal in a corresponding sub-time period sequentially lights up the multiple light-emitting diodes in the total time period in a time-sharing manner: the effective logic values, such as logic high, of the third pwm signal D3 are distributed in the first sub-period T1, the effective logic values, such as logic high, of the first pwm signal D1 are distributed in the second sub-period T2, and the effective logic values, such as logic high, of the second pwm signal D2 are distributed in the third sub-period T3. In the total time period, the multiple paths of light-emitting diodes are sequentially lightened in a time-sharing manner: the red led is turned on when the pwm signal D3 has an active logic value in the first sub-period T1, the green led is turned on when the pwm signal D1 has an active logic value in the second sub-period T2, and the blue led is turned on when the pwm signal D2 has an active logic value in the third sub-period T3. The result is that the red leds will not light up in T2-T3, and the green leds will not light up in T1 and T3, and the blue leds will not light up in T1 and T2. The desired result of the red and green and blue leds being time-shared lit in the monochrome mode is achieved. The effective logic value, e.g., the duty ratio of high level, of the third pwm signal D3 is adjusted in the first sub-period T1, the effective logic value, e.g., the duty ratio of high level, of the first pwm signal D1 is adjusted in the second sub-period T2, and the effective logic value, e.g., the duty ratio of high level, of the second pwm signal D2 is adjusted in the third sub-period T3. Besides the time-sharing lighting sequence of red, green, blue, green, red, blue, green, blue, red, blue, green, blue and green, the order of the high level of the first to the third pulse width modulation signals is reasonably arranged as a countermeasure.

Referring to fig. 19, node Nod is coupled to the power supply input VCC. The constant current unit CS3, the switch S7 and the resistor r7 are connected in series between the pin 563 and the node Nod. According to the same principle, a constant current unit CS1, a switch S8 and a resistor r8 are sequentially connected in series between the pin 562 and the node Nod. According to the same principle, a constant current unit CS2, a switch S9 and a resistor r9 are sequentially connected in series between the pin 561 and the node Nod. In the improved topology, another resistor is allowed to be separately arranged between the node Nod and the power supply input end, and the resistor r7, the resistor r8 and the resistor r9 can reduce the resistance value.

Referring to fig. 19, for all three primary color display units mentioned earlier and later herein, the sum of the first current value flowing through the green light emitting diode and the second current value flowing through the blue light emitting diode is equal to the third current value flowing through the red light emitting diode, and accordingly, relatively pure white light can be generated. In the conventional scheme of generating white light by mixing red, green and blue, it is assumed that the current supplied to the red led is IR, the current supplied to the green led is IG, and the current supplied to the blue led is IB, and accordingly, the on-off duty ratio of the current IR is DR, the on-off duty ratio of the current IG is DG, and the on-off duty ratio of the current IB is DB. When white light is generated, the purity of the white light is influenced by at least the three current values and the three duty ratios. Generally, the current accuracy depends on the constant current unit and the duty ratio depends on the gradation data assigned to each color. The alternative solution mentioned here is much more compact than the traditional color mixing to produce white light: only the first current value I1 flowing through the green led and the second current value I2 flowing through the blue led need to be controlled, and there is no need to control the third current value I3 separately because the third current value I3 follows the first current value I1 and the second current value I2 in a very precise manner. The first pwm signal D1, the second pwm signal D2, and even the third pwm signal D3 are synchronization signals, and the gray scale data defined for the white light can be adjusted and the duty ratios of the first, second, and third pwm signals can be determined, which allows the duty ratios of the three to be identical in the white light mode. It is not to be considered that the solution of the present application requires a much smaller number of precisely controlled parameters when generating white light than the conventional solution. Generally, the more the parameter amount, the more difficult it is to control the white light purity, because almost all parameters have more or less slight errors, and the less the parameter amount, the smaller the total error. Considering that the average current flowing through any type of diode is the result of multiplying the current value by the actual duty ratio of the current, it is obvious that the white light generated by the three primary color display units of the present application is far purer in purity than the traditional scheme, and the color cast phenomenon is greatly reduced. The term gray level in the industry refers to the degree of change from darkest black to brightest white, and the higher the gray level of the primary colors, the more colorful the color expression. Taking eight-bit gray scale data as an example, the duty ratio of the gray scale data containing eight binary zeros is close to zero percent, and the duty ratio of the gray scale data containing eight binary ones is close to one hundred percent.

Referring to fig. 19, for all the three-primary-color display units mentioned earlier and later, the parallel structure formed by the green and blue light emitting diodes is further arranged and connected in series with the red light emitting diode, so that the differential working voltages can be provided for the red, green and blue light emitting diodes at the same time. In the traditional scheme of generating white light by mixing red, green and blue, the power supply voltage is almost directly applied to the LEDs of red, green and blue, so that the working voltages of the LEDs of red, green and blue are basically the same in the turn-on and lighting stage, and the higher power supply voltage can meet the working voltage requirements of the LEDs of green and blue but causes the low efficiency of the LEDs of red. The alternative solution mentioned here may solve this concern compared to the traditional color mixing approach to produce white light: the parallel structure containing the green and blue light-emitting diodes and the red light-emitting diodes play a role in voltage division and bear a power supply voltage together, so that the voltage drop at two ends of the red light-emitting diodes is closer to the actually required working voltage, and the voltage drop at two ends of the parallel structure containing the green and blue light-emitting diodes is closer to the actually required working voltage of the green and blue light-emitting diodes, so that the light-emitting diodes of all colors operate in the working voltage environment according with the voltage characteristics of the light-emitting diodes. This is also beneficial for improving the white light purity. Even if the three-primary color display unit is switched from generating white light to generating color or monochrome, different working voltages can still be provided for the light emitting diodes of all colors.

Referring to fig. 20, the four-pin type three-in-one lamp bead includes four pins. The pin type mentioned herein includes a pin of an in-line package structure or a pin of a surface mount package structure or a pin of a chip-on-board package structure, etc. In this embodiment, the cathodes of the green-blue leds are coupled together, in other words, the cathodes of the green-blue leds are all electrically connected to the same pin 603 but the anodes of the green-blue leds are separated. The anode and cathode of the red light emitting diode R are correspondingly electrically connected to the

pins

603 and 604, respectively. And the green light emitting diode G is electrically connected to the

pins

602 and 603, respectively, at its anode and cathode, respectively. And the blue light emitting diode B is electrically connected to the

leads

601 and 603, respectively, at its anode and cathode, respectively. The packaging body PAK shown in the figure mainly functions to encapsulate the internal red, green and blue three-primary-color light emitting diodes in a plastic package manner for sealing, and the light-transmitting area LENS mainly functions to allow the light rays emitted by the three-primary-color light emitting diodes to be emitted from the area, and also belongs to the RGB-LED packaging type.

Referring to fig. 21, the driving chip and the light emitting diode are integrated into the same package. The driving chip 500 and the three primary color display unit 600 driven thereby are integrated into the same package. The package PAK mainly functions to encapsulate the rgb leds and the driving chip therein, and the transparent region LENS mainly functions to allow the light emitted from the rgb leds to be emitted from the transparent region. The pins of the package are omitted from the figure.

Referring to fig. 22, explanation is made using a cascade-connected multi-stage driver chip. The cascade driving chips in this example are arranged in a row, i.e., connected in parallel, on the power supply path. The master node MST sends communication data to each level of drive chips, and the master node may use a server or a microprocessor or similar data sending end. The power supply path is as follows: the power input terminal VCC of any driver chip in each row of driver chips is coupled to the positive terminal NP of the external power source and the potential reference terminal OUT is coupled to the negative terminal VN of the external power source. And (3) in the aspect of cascade connection: the signal output terminal DO of the previous or previous driver chip may be configured to be coupled to the signal input terminal DI of the next or next driver chip through a coupling capacitor C. For example, after intercepting the communication data belonging to the first driver chip in the communication data, the first driver chip forwards the rest of the received communication data to the second driver chip cascaded with the first driver chip, and after intercepting the communication data belonging to the second driver chip in the communication data, the second driver chip forwards the rest of the received communication data to the third driver chip cascaded with the second driver chip, and so on.

Referring to fig. 23, the explanation is still made by using cascaded multi-stage driver chips. Note that the cascade driver chips are arranged in a row on the power supply path, i.e., the driver chips are connected in parallel, and in contrast, the cascade driver chips in this example are connected in one or more rows on the power supply path, i.e., the driver chips are connected in series. The master node MST transmits communication data to each level of driver chip and the master node may use a server or a microprocessor or the like as a data transmitting terminal. The signal output terminal DO of the previous or previous driver chip may be configured to be coupled to the signal input terminal DI of the next or next driver chip through a coupling capacitor C, for transmitting communication data to the driver chips or current sources in the form of a column.

Referring to fig. 23, the cascade driving chips are arranged in one or more columns in the power supply path. The power supply input terminal VCC of the first driver chip 500 as the head of the column in each column is coupled to the power supply positive electrode VP, and the potential reference terminal GND of the last driver chip 500 as the tail of the column is coupled to the power supply negative electrode VN. The power supply input terminal of the following driver chip is also provided in each column to be coupled to the potential reference terminal of the preceding driver circuit. In the present example, the power input VCC of the second driver chip 500 is coupled to the current outlet of the adjacent first driver chip 500, i.e., the potential reference GND, as in the first column. The power input terminal VCC of the third driver chip 500 in the first column is connected to the current outflow terminal, i.e., the potential reference terminal GND, of the adjacent second driver chip 500. And for example, the power input terminal VCC of the fourth driver chip 500 may be coupled to the current outflow terminal, i.e., the potential reference terminal GND, of the adjacent third driver chip 500 in the first column. The power input VCC of the last driver chip 500 in the first column is coupled to the current drain, i.e., the potential reference GND, of the second to last driver chip 500. For another example, it may be provided in the first column that the power input VCC of the second last driver chip 500 is coupled to the current outlet of the third last driver chip 500, i.e., the potential reference GND. Thus, it can be seen that: the power input end of the rear driving chip in each row is coupled to the potential reference end of the adjacent front driving chip in the power supply relation of the cascade driving chips until all the driving chips in each row are connected in series or superposed between the positive electrode VP and the negative electrode VN of the external direct-current power supply. As a voltage stabilizing option, a capacitor CZ is arranged between the power input terminal VCC and the potential reference terminal GND of each driving chip. The total output current of the previous driver chip in each column can be considered as the total input current of the adjacent subsequent driver chip, or the total input current of all driver chips in each column can be considered to be equal, which is determined by the serial structure of all driver chips.

Referring to fig. 23, a power supply line of each column of driving chips, such as the first column of driving chips, is provided with a current source ICS module for maintaining the total input current of each driving chip in the column at a predetermined value. In the first column on the left, the respective driver chip 500 and the current source module ICS are connected in series between the positive pole and the negative pole of the power supply. The current input terminal VCC of the first driver chip 500 is not directly connected to the positive electrode VP of the external power supply but indirectly coupled to the positive electrode of the external power supply through the current source ICS module. The current input terminal of the current source ICS module is connected to the external power supply positive electrode VP, and the current output terminal of the current source ICS module is connected to the power supply input terminal VCC of the first driver chip 500. The current source functions to provide a highly accurate and stable output current to a target object having a constant current requirement, the current input terminal of the current source is also its own voltage supply terminal and the current output terminal of the current source provides the output current. The current source ICS decodes the current adjustment data from the received communication data and adjusts the magnitude of the output current according to the current adjustment data. The position of the current source ICS can be adjusted between the potential reference terminal GND of the last driver chip 500 and the negative terminal VN of the external power source, for example, the current input terminal of the current source module is connected to the potential reference terminal GND of the last driver chip 500 and the current output terminal of the current source module is connected to the negative terminal VN of the external dc power source. Alternatively, the position of the current source ICS may be adjusted between any two adjacent driver chips 500: for example, in any adjacent two of the front and rear driver chips, it is asserted that the current input terminal of the current source module is connected to the potential reference terminal GND of the front driver chip 500, and the current output terminal of the current source module is connected to the power supply input terminal VCC of the rear driver chip 500. The definition of current source ICS is that it requires the total value of the input current flowing from its current input to be equal to the total value of the output current flowing from its current output. Therefore, the total input current of any one of the driving chips in each row is equal to the output current of the current source module, the current source module in each row of the driving chips is connected in series with the driving chip 500, and the total input current of any one of the driving chips 500 in each row of the driving chips is limited to a predetermined value determined by the current source ICS module. In a modified embodiment: the current source ICS module has no communication function for receiving communication data or current regulation data, which is equivalent to setting the output current provided by the current source ICS to be fixed and not programmable online. In a modified embodiment: the current source ICS module is omitted so that each driving chip is directly connected in series between the positive electrode VP and the negative electrode VN of the external power supply. Current source chips already exist in the prior art.

Referring to fig. 23, it is recalled that the aforesaid conventional four-pin or six-pin three-in-one lamp beads have to meet the power supply voltage requirements of the leds of different colors, but the essential characteristics of the leds of different colors determine that the operating voltages required by the leds are not completely the same, which is disadvantageous in that the voltage range of the power supply voltage is limited. So the compromise scheme of the trinity lamp pearl of traditional four pin formulas or six pin formulas is: the voltage of about 3-4V provided by the driving chip is directly applied to the light emitting diodes of the various colors which are connected in parallel. If the voltage between the power input terminal VCC and the potential reference terminal GND of the driver chip is clamped to 3-4 v to meet the power supply voltage requirement of the light emitting diode, the number of driver chips to be arranged and stacked between the positive electrode VP and the negative electrode VN is quite large, and more driver chips are stacked to adapt to a higher power supply voltage when the power supply voltage between the positive electrode VP and the negative electrode VN is larger. However, in the display field, the arrangement density of the pixels is flexibly calculated according to actual requirements and application environments. The voltage value at two ends of the red light-emitting diode is adjusted to be in a range of 1.8-3 volts, the voltage value at two ends of the green-blue light-emitting diode is adjusted to be in a range of 3-4 volts, and if the three-primary-color light-emitting unit is matched with the driving chip for use, the voltage supplied by the driving chip to the three-primary-color light-emitting unit is allowed to be about 6 volts. The three primary color light emitting unit in the present invention allows to connect a smaller number of driving chips in series between the positive electrode VP and the negative electrode VN, which is very important for flexibly arranging the density of the pixel points, so that the fundamental reason of the difference is that the three primary color light emitting unit mentioned herein can bear higher voltage drop, and the limitation of clamping the voltage of the driving chips to a low level is eliminated.

While the present invention has been described with reference to the preferred embodiments and illustrative embodiments, it is to be understood that the invention as described is not limited to the disclosed embodiments. Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. It is therefore intended that the appended claims be interpreted as covering all alterations and modifications as fall within the true spirit and scope of the invention. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of the present invention.

Claims

1. A three primary color display unit, comprising:

green and blue light emitting diodes arranged in parallel;

a red light emitting diode disposed in series with both the green and blue light emitting diodes;

arranging a cathode of the red light emitting diode to be coupled to respective anodes of the green and blue light emitting diodes; or

Arranging an anode of the red light emitting diode to be coupled to respective cathodes of the green and blue light emitting diodes;

the three primary colors of red, green and blue are superposed to form color:

in the color mode, the respective lighting periods of the red, green, and blue light emitting diodes are set to overlap, and the respective lighting periods of the red, green, and blue light emitting diodes are set to be the same or different;

2. The three primary color display unit of claim 1, wherein:

in a color mode, a first current value provided for the green light emitting diode is switched between the green light emitting diode and the first shunting branch, and a second current value provided for the blue light emitting diode is switched between the blue light emitting diode and the first shunting branch; and

and a total current obtained by adding the first current value and the second current value is switched to flow between the red light-emitting diode and the second shunt branch.

3. A three primary color light bead comprising:

the three primary colors of red, green and blue are superposed to form color:

in the color mode, the respective lighting periods of the red, green and blue light emitting diodes are set to overlap, and the respective lighting periods of the red, green and blue light emitting diodes are also set to be the same or different;

4. A three primary color light bead comprising:

the three primary colors of red, green and blue are superposed to form color:

5. A three primary colors color mixing method is characterized in that:

Coupling an anode of the red light emitting diode to respective cathodes of the green and blue light emitting diodes;

setting the respective lighting time periods of the red, green and blue light emitting diodes to be overlapped, and setting the respective lighting time periods of the red, green and blue light emitting diodes to be the same or different;

6. The method of claim 5, wherein:

providing first and second current values in the form of pulsed currents, during each cycle: