A tandem LED driver and LED system with built-in calibrable parameters

Abstract

This invention provides a serial LED driver and LED system with a built-in calibrable parameter. The serial LED driver transmits a grayscale vector, a correction parameter matrix, or an appropriate current value vector. It includes: a non-volatile memory that receives and stores calibrable parameters corresponding to an LED for LED calibration; a correction matrix processing unit that reads elements of a correction parameter matrix corresponding to the LED and pre-stored in the non-volatile memory, receives a grayscale vector, and performs matrix operations between the grayscale vector and the correction parameter matrix to generate a first new grayscale vector; a pulse width modulation circuit that outputs a constant current to the LED based on the first new grayscale vector; or the pulse width modulation circuit outputs another corresponding constant current to the LED based on an appropriate current value vector corresponding to the LED pre-stored in the non-volatile memory and the first new grayscale vector to adjust the LED.

Description

Technical Field

[0001] This invention relates to a light-emitting diode (LED) device, and more particularly to a series LED driver device and LED system with built-in calibrable parameters. Background Technology

[0002] To meet the light emission range that customers can use, LED packaging manufacturers currently select LEDs with similar characteristics and categorize them into bins, so that LEDs of the same bin can meet the required light emission range.

[0003] However, even when LED packaging manufacturers select LEDs with similar characteristics, the luminous brightness of LED chips of the same grade still has an error of ±10%. Therefore, for customers who require high quality, the quality of the assembled LED system still cannot meet their needs. Summary of the Invention

[0004] One of the objectives of this invention is to provide an LED driver device with nonvolatile memory for storing calibrable parameters used to calibrate LED beads.

[0005] One of the objectives of this invention is to enable the LED driver to perform calculations on the grayscale input received and calibrable parameters stored in non-volatile memory, thereby achieving a more accurate color setting for the LED beads.

[0006] One of the objectives of this invention is to improve the quality of LED beads by achieving an accuracy error of less than ±2% in the luminous brightness of LED beads.

[0007] One of the objectives of this invention is to allow for the selection of the light-emitting range of movable LED beads, thereby reducing the inventory requirements for LED beads of different grades, achieving flexible production allocation, increasing production applicability, and enhancing value.

[0008] In a first aspect, the present invention provides a serial LED driver device with a built-in calibrable parameter, the serial LED driver device transmitting a grayscale vector or a correction parameter matrix or an appropriate current value vector, comprising: a non-volatile memory for receiving and storing calibrable parameters corresponding to an LED for LED calibration; a correction matrix processing unit for reading elements of a correction parameter matrix corresponding to the LED and pre-stored in the non-volatile memory, receiving a grayscale vector, and performing matrix operations between the grayscale vector and the correction parameter matrix to generate a first new grayscale vector; and a pulse width modulation circuit for outputting a constant current to the LED based on the first new grayscale vector to adjust the LED; or the pulse width modulation circuit outputting another corresponding constant current to the LED based on the appropriate current value vector corresponding to the LED pre-stored in the non-volatile memory and the first new grayscale vector to adjust the LED.

[0009] Optionally, in one embodiment of the present invention, the LED bead has a corresponding bin level. When the original bin level is adjusted to a new bin level, the correction matrix processing unit receives the new correction parameter matrix, and the correction matrix processing unit performs matrix multiplication of the grayscale vector with the new correction parameter matrix to generate a second new grayscale vector.

[0010] Optionally, the calibrable parameters provided in one embodiment of the present invention include an RGB grayscale component or an RGB grayscale component and its appropriate RGB current value vector corresponding to the LED chip.

[0011] Secondly, the present invention provides an LED display system having a serial LED driver device with a built-in calibrable parameter. The LED display system includes: a microcontroller device for transmitting a grayscale vector, a correction parameter matrix, or an appropriate current value vector; multiple serial LED drivers forming an array, each serial LED driver including: an LED chip; a non-volatile memory for receiving and storing calibrable parameters corresponding to the LED chip for LED chip calibration; and a correction matrix processing unit for reading the corresponding calibrable parameters. The LED chip is provided with elements of a correction parameter matrix pre-stored in the non-volatile memory, a grayscale vector is received, and a matrix operation is performed between the grayscale vector and the correction parameter matrix to generate a first new grayscale vector; and a pulse width modulation circuit outputs a constant current to the LED chip according to the first new grayscale vector to adjust the LED chip; or the pulse width modulation circuit outputs another corresponding constant current to the LED chip according to the appropriate current value vector corresponding to the LED chip pre-stored in the non-volatile memory and the first new grayscale vector to adjust the LED chip. Attached Figure Description

[0012] The present invention can be more fully understood through the following detailed description of the embodiments in conjunction with the accompanying drawings, in which:

[0013] Figure 1A This diagram shows an embodiment of an LED display system according to the present invention.

[0014] Figure 1B This diagram shows an embodiment of an LED display system according to the present invention.

[0015] Figure 2A This diagram shows an embodiment of an LED display system according to the present invention.

[0016] Figure 2B This diagram shows an embodiment of an LED display system according to the present invention.

[0017] Figure 3 This diagram shows a serial LED driver device according to an embodiment of the present invention.

[0018] Figure 4 This diagram shows a serial LED driver device according to an embodiment of the present invention.

[0019] Figure 5 This diagram shows a serial LED driver device according to an embodiment of the present invention.

[0020] Figure 6 This diagram shows a serial LED driver device according to an embodiment of the present invention.

[0021] Figure 7 This diagram shows a serial LED driver device according to an embodiment of the present invention.

[0022] The symbols shown in the diagram are explained as follows:

[0023] 10, 11, 20, 21: LED display system;

[0024] 100, 200, 300, 400, 500, 600, 700: Serial LED driver;

[0025] MCU: Microcontroller device;

[0026] 30: Non-volatile memory;

[0027] 31: Correction matrix processing unit;

[0028] 32: Pulse width modulation circuit;

[0029] 33: Encoder / decoder concatenation unit;

[0030] 10b, R, G, B: LED beads;

[0031] SDIP, SDIN, SDOP, SDON: Serial data input / output interfaces;

[0032] POWER: Voltage source;

[0033] VLED: Forward voltage;

[0034] R-ch1, G-ch1, B-ch1, R-ch2, G-ch2, B-ch2: constant current;

[0035] SW1, SW2: Power supply time-sharing unit. Detailed Implementation

[0036] Please refer to Figure 1A , Figure 1A This diagram illustrates an LED display system according to an embodiment of the present invention. The LED display system 10 includes a microcontroller (MCU), multiple serial LED drivers 100, and LED beads 10b. Note that the LED drivers 100 are connected in a single-ended serial link, meaning that adjacent LED drivers 100 are coupled in a single-ended serial connection. The MCU transmits grayscale vectors and correction parameter matrices using single-ended signals.

[0037] Figure 1A Although the LED display system 10 indicates that each serial LED driver is a single pixel lamp bead 10b, the present invention should not be limited thereto. Figure 1BAs shown, the LED display system 11 can also be a two-pixel lamp bead 10b architecture, that is, each serial LED driver device may include multiple pixel lamp beads 10b.

[0038] Please refer to Figure 2A , Figure 2A This diagram illustrates an embodiment of an LED display system 20 of the present invention. The LED display system 20 includes a microcontroller unit (MCU), multiple serial LED drivers 200, and LED beads 10b. Note that the LED drivers 200 are connected in a differential serial link. The MCU transmits grayscale vectors, correction parameter matrices, or appropriate current value vectors using differential signals. The MCU can also transmit single-ended signals to the first LED driver 200, while the first LED driver 200 transmits signals to other LED drivers 200 using differential signals.

[0039] Figure 2A Although the present invention is described as having a single-pixel lamp bead 10b architecture for each serial LED driver in the LED display system 10, it should not be limited thereto. Figure 2B As shown, the LED display system 21 can also be a two-pixel lamp bead 10b architecture, that is, each serial LED driver device may include multiple pixel lamp beads 10b.

[0040] Please refer to Figure 3 , Figure 3 This diagram illustrates a serial LED driver device 300 according to an embodiment of the present invention. The serial LED driver device 300 includes a non-volatile memory 30, a correction matrix processing unit 31, a pulse width modulation circuit 32, an encoding / decoding serial connection unit 33, and LED beads 10b. The serial LED driver device 300 uses serial data input / output interfaces SDIP and SDOP, and the data transmission through SDIP and SDOP is bidirectional, for example... Figure 1A As shown, the microcontroller device (MCU) can transmit commands and write data, and can also read data from other serial LED drivers 300, i.e., the status of the serial LED drivers 300 and the LED beads 10b (e.g., open circuit / short circuit); in addition, the voltage source POWER represents the input voltage.

[0041] The correction matrix processing unit 31 reads all matrix elements in the correction parameter matrix corresponding to the LED and pre-stored in the non-volatile memory 30, receives the grayscale vector, and performs matrix operations between the grayscale vector and the correction parameter matrix to generate a first new grayscale vector.

[0042] The pulse width modulation circuit 32 is coupled to the correction matrix processing unit 31 and outputs a constant current to the LED bead 10b according to the first new grayscale vector to adjust the grayscale or brightness of the LED bead 10b.

[0043] In another embodiment, the non-volatile memory 30 pre-stores an appropriate current value vector corresponding to the LED bead 10b. The pulse width modulation circuit 32 adjusts the LED bead 10b by outputting another constant current to the LED bead 10b based on the appropriate current value vector pre-stored in the non-volatile memory 30 and the first new grayscale vector.

[0044] In a pre-calibration embodiment (not shown), when the color accuracy error of the LED bead 10b is less than ±2%, the calibration matrix processing unit 31 stops the pre-calibration operation of the grayscale vector and the calibration parameter matrix. At this time, the non-volatile memory 30 stores all matrix elements in the calibration parameter matrix corresponding to the LED bead 10b, which become calibrable parameters.

[0045] Finally, the encoding / decoding concatenation unit 33 encodes the grayscale vector, correction parameter matrix, or appropriate current value vector to generate encoded data, which is then transmitted to another serial LED driver 300 via the serial data output interface SDOP. Alternatively, it decodes the encoded data received from another serial LED driver 300 via the serial data input interface SDIP into a grayscale matrix or correction parameter matrix and transmits it to the correction matrix processing unit 31. In one embodiment, the encoding / decoding concatenation unit 33 decodes the encoded data received from another serial LED driver 300 into an appropriate current value vector and transmits it to the pulse width modulation circuit 32. The data transmission via the serial data input / output interfaces SDIP and SDOP is bidirectional single-ended serial, and the microcontroller device MCU can transmit commands and write data to the correction matrix processing unit 31.

[0046] Please note that this embodiment can be used as a binning (BIN) operation, i.e., adjusting the light emission range of LED bead 10b. Please also refer to Table 1 below. The bead has an original level. If the user needs to adjust the original level to a new level (e.g., from group S3 level to R3 level), the light emission intensity of LED bead 10b needs to be adjusted. Therefore, the correction matrix processing unit 31 receives a new correction parameter matrix, and the correction matrix processing unit 31 performs matrix multiplication of the grayscale vector with the new correction parameter matrix to generate a second new grayscale vector.

[0047] Table 1. Luminance Intensity Corresponding to Bin Levels

[0048] Group Minimum value (microcandlelight mcd) Maximum value (micro-candlelight mcd) R3 100 140 S3 140 200 T3 200 285 U3 285 400 V3 400 560

[0049] When the brightness of the LED bead 10b corresponding to the second new grayscale vector meets the corresponding new level, all matrix elements in the correction parameter matrix corresponding to the LED bead 10b stored in the non-volatile memory become calibrable parameters.

[0050] The aforementioned calibrable parameters include an RGB grayscale component or an RGB grayscale component and its appropriate RGB current value vector corresponding to the LED bead 10b, that is, the grayscale components of each color such as red bead R, green bead G, and blue bead B and their corresponding appropriate current value vectors.

[0051] Please refer to Figure 4 , Figure 4 This diagram illustrates a serial LED driver device according to an embodiment of the present invention. The serial LED driver device 400 differs from the serial LED driver device 300 in that the serial data input / output interfaces SDIP, SDIN, SDOP, and SDON transmit data in a bidirectional differential sequence. The microcontroller device MCU transmits grayscale vectors, correction parameter matrices, or appropriate current value vectors using differential signals. The serial data input / output interfaces SDIP, SDIN, SDOP, and SDON are implemented using the Manchester codec.

[0052] Because the differential sequence cascading in this embodiment can not only reduce the impact of common-mode noise, it can also reduce noise emissions. When two adjacent lines of the differential combination transmit data, the current will flow equally to both sides, thereby generating equal, relative, and mutually canceling electromagnetic fields.

[0053] In addition, the differential sequence cascading in this embodiment can provide a higher data rate, thus enabling the transmission of a series of multiple serial drive devices through a single channel sequence.

[0054] Please refer to Figure 5 , Figure 5 This diagram shows a schematic of a serial LED driving device according to an embodiment of the present invention. The difference between the serial LED driving device 500 and the serial LED driving device 400 is that the serial LED driving device 500 has a two-pixel LED bead 10b architecture, that is, each serial LED driving device 500 may contain multiple pixel LED beads 10b.

[0055] Please refer to Figure 6 , Figure 6 This diagram shows a series LED driving device according to an embodiment of the present invention. The difference between the series LED driving device 600 and the series LED driving device 500 is that the series LED driving device 600 has a four-pixel LED chip 10b architecture, where the voltage VLED represents the forward voltage.

[0056] Please refer to Figure 7, Figure 7 This diagram illustrates a series LED driver device according to an embodiment of the present invention. The difference between the series LED driver device 700 and the series LED driver device 600 is that the series LED driver device 700 has built-in power time-sharing switching units SW1 and SW2. The power time-sharing switching units SW1 and SW2 can be used for driving and discharging. That is, when the power time-sharing switching units SW1 or SW2 are turned on or off to drive and discharge the LED beads 10b, the pulse width modulation circuit 32 generates constant currents R-ch1, G-ch1, B-ch1, R-ch2, G-ch2, and B-ch2 corresponding to each red LED bead R, green LED bead G, and blue LED bead B at different times, so as to drive each red LED bead R, green LED bead G, and blue LED bead B or discharge each red LED bead R, green LED bead G, and blue LED bead B at different times; the other correction principles are the same as described above and will not be repeated here.

[0057] In summary, the present invention enables the LED driver to perform calculations with the input grayscale vector and calibrable parameters stored in non-volatile memory, thereby achieving a more accurate color setting for the LED beads; or it can selectively move the light emission range of the LED beads to reduce the inventory requirements of different grades of LED beads.

Claims

1. A tandem LED driver device with a built-in calibrable parameter, characterized in that, The serial LED driver transmits a grayscale vector, a correction parameter matrix, or an appropriate current value vector. The device includes: A non-volatile memory is used to receive and store calibrable parameters corresponding to an LED, the calibrable parameters being used for LED calibration; A correction matrix processing unit reads elements of the correction parameter matrix corresponding to the LED beads and pre-stored in the non-volatile memory, receives the grayscale vector, and performs matrix operations between the grayscale vector and the correction parameter matrix to generate a first new grayscale vector; and A pulse width modulation circuit outputs a constant current to the LED based on the first new grayscale vector to adjust the LED; or the pulse width modulation circuit outputs another corresponding constant current to the LED based on the appropriate current value vector corresponding to the LED stored in the non-volatile memory and the first new grayscale vector to adjust the LED. The LED beads have a corresponding grade, the correction matrix processing unit receives the new correction parameter matrix, and the correction matrix processing unit performs matrix multiplication of the gray vector with the new correction parameter matrix to generate a second new gray vector, so that the original grade is shifted to the new grade.

2. The serial LED driving device according to claim 1, characterized in that, When the color accuracy error of the LED bead is less than ±2%, the correction matrix processing unit stops the pre-calibration operation of the grayscale vector and the correction parameter matrix. At this time, the non-volatile memory stores all matrix elements of the correction parameter matrix corresponding to the LED bead, which become the calibrable parameters.

3. The serial LED driving device according to claim 2, characterized in that, When the brightness of the LED corresponding to the second new grayscale vector meets the corresponding new level, the non-volatile memory stores the level calibrable parameter corresponding to the LED.

4. The serial LED driving device according to claim 1, characterized in that, The device includes: A codec unit encodes the grayscale vector, the correction parameter matrix, or the appropriate current value vector to generate encoded data and transmits it to another cascaded LED driver device; or it decodes the encoded data received from another cascaded LED driver device into the grayscale vector or the correction parameter matrix and transmits it to the correction matrix processing unit; or it decodes the data into the appropriate current value vector and transmits it to the pulse width modulation circuit.

5. The serial LED driving device according to claim 1, characterized in that, The calibrable parameters include an RGB grayscale component corresponding to the LED chip or an appropriate current value vector corresponding to an RGB grayscale component and its RGB values ​​of the LED chip.

6. An LED display system, characterized in that, The LED display system includes: A microcontroller device that transmits a grayscale vector, a correction parameter matrix, or an appropriate current value vector; Multiple series LED drivers are arranged in an array, and each series LED driver includes: One LED light bead; A non-volatile memory is used to receive and store a calibrable parameter corresponding to the LED, the calibrable parameter being used for LED calibration; A correction matrix processing unit reads elements of the correction parameter matrix corresponding to the LED beads and pre-stored in the non-volatile memory, receives the grayscale vector, and performs matrix operations between the grayscale vector and the correction parameter matrix to generate a first new grayscale vector; and A pulse width modulation circuit outputs a constant current to the LED based on the first new grayscale vector to adjust the LED; or the pulse width modulation circuit outputs another corresponding constant current to the LED based on the appropriate current value vector corresponding to the LED stored in the non-volatile memory and the first new grayscale vector to adjust the LED. The LED beads have a corresponding grade, the correction matrix processing unit receives the new correction parameter matrix, and the correction matrix processing unit performs matrix multiplication of the grayscale vector with the new correction parameter matrix to generate a second new grayscale vector, so that the original grade is adjusted to the new grade.

7. The LED display system according to claim 6, characterized in that, When the color accuracy error of the LED bead is less than ±2%, the correction matrix processing unit stops the pre-calibration operation of the grayscale vector and the correction parameter matrix. At this time, the non-volatile memory stores all matrix elements in the correction parameter matrix corresponding to the LED bead, which become the calibrable parameters.

8. The LED display system according to claim 7, characterized in that, When the brightness of the LED corresponding to the second new grayscale vector meets the corresponding new level, the non-volatile memory stores the caliable parameters corresponding to the LED.

9. The LED display system according to claim 6, characterized in that, The serial LED driver includes: A codec serial unit encodes the grayscale vector, the correction parameter matrix, or an appropriate current value vector to generate encoded data and transmits it to another serial LED driver device; or it decodes the encoded data received from another serial LED driver device into the grayscale vector or the correction parameter matrix and transmits it to the correction matrix processing unit; or it decodes it into an appropriate current value vector and transmits it to the pulse width modulation circuit.

10. The LED display system according to claim 6, characterized in that, The calibrable parameters include an RGB grayscale component corresponding to the LED chip or an RGB grayscale component of the LED chip and its appropriate RGB current value vector.

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