Light emitting diode control system

Abstract

The invention provides a light-emitting diode control system, comprising a light-emitting diode array which is composed of a plurality of light-emitting diode channels, and each light-emitting diode channel comprises a plurality of light-emitting diodes; the plurality of light emitting diode drivers are sequentially connected to respectively drive the corresponding light emitting diode channels, and the light emitting diode channels are sequentially controlled by the light emitting diode drivers; and the light-emitting diode controller is used for sending the brightness data to the light-emitting diode driver so as to control the brightness of the light-emitting diode. After the brightness input data is transmitted to the related light-emitting diode driver, the brightness input data is replaced by state data of the related light-emitting diode driver, and the state data is finally read by the light-emitting diode controller through other light-emitting diode drivers.

Description

Technical Field

[0001] The present invention relates to a light emitting diode (LED) control system, and more particularly to an LED control system capable of reading error status. Background Art

[0002] Touch screens are a widely adopted human-machine interface and can be applied to in-vehicle applications to enhance the driving experience. The touch panel of the touch screen, as an input interface of the in-vehicle device, is gradually replacing traditional in-vehicle input interfaces, such as rotary controllers, steering wheel controls, and touch pads.

[0003] Serial Peripheral Interface (SPI) is a synchronous serial communication specification mainly used in embedded systems and suitable for short-distance wired communication between electronic devices for in-vehicle applications. Serial Peripheral Interface (SPI) can be used as an LED driver interface between an LED driver and a microcontroller (or other devices that control the LED driver).

[0004] Due to the harsh environment faced by in-vehicle applications, it is necessary to monitor the correctness of the system at any time by reading the error status. However, if the number of LEDs is large, the pulse width modulation (PWM) duty cycle to be transmitted to the LEDs will become very large. The additional error status reading will occupy additional bandwidth and affect the number of supportable LEDs. The control program of the microcontroller becomes more complex, and a control delay is required before sending a command to read the error status to ensure that each LED driver has received the pulse width modulation (PWM) duty cycle. At the same time, additional overhead data is also required.

[0005] Therefore, there is an urgent need to propose a novel mechanism to overcome the deficiencies of traditional LED control systems. Summary of the Invention

[0006] In view of the above, one of the objectives of the embodiments of the present invention is to provide an LED control system that can read error status, has a simplified mechanism, and does not increase bandwidth.

[0007] According to an embodiment of the present invention, a light-emitting diode control system includes a light-emitting diode array, a plurality of light-emitting diode drivers, and a light-emitting diode controller. The light-emitting diode array is composed of a plurality of light-emitting diode channels, and each light-emitting diode channel includes a plurality of light-emitting diodes. The light-emitting diode drivers are sequentially connected to drive the corresponding light-emitting diode channels respectively, and the light-emitting diode channels are sequentially controlled by the light-emitting diode drivers. The light-emitting diode controller is used to send brightness data to the light-emitting diode drivers to control the brightness of the light-emitting diodes. After the brightness input data is transmitted to the relevant light-emitting diode driver, the brightness input data is replaced by the status data of the relevant light-emitting diode driver, which is finally read by the light-emitting diode controller via other light-emitting diode drivers.

[0008] In one embodiment of the present invention, the plurality of light-emitting diode channels are sequentially controlled by the plurality of light-emitting diode drivers connected in a daisy chain.

[0009] In one embodiment of the present invention, it further includes a timing controller, which includes the light-emitting diode controller.

[0010] In one embodiment of the present invention, a synchronous serial communication interface is used between the light-emitting diode controller and the light-emitting diode driver as the light-emitting diode driver interface.

[0011] In one embodiment of the present invention, the synchronous serial communication interface includes a serial peripheral interface.

[0012] In one embodiment of the present invention, each light-emitting diode driver receives brightness input data from the previous light-emitting diode driver and each light-emitting diode driver sends brightness output data to the next light-emitting diode driver, while the first light-emitting diode driver receives brightness input data from the light-emitting diode controller and the last light-emitting diode driver sends brightness output data back to the light-emitting diode controller.

[0013] In one embodiment of the present invention, the status data includes an error status.

[0014] In one embodiment of the present invention, the replacement status data is finally read by the light-emitting diode controller without using an additional status read command.

[0015] In one embodiment of the present invention, the brightness input data is replaced by the status data every few frames.

[0016] In one embodiment of the present invention, when the frame is not replaced by the status data, an empty command is used, which changes the data to 0.

[0017] In one embodiment of the present invention, the brightness data includes a pulse width modulation duty cycle. Description of the Drawings

[0018] Figure 1A A block diagram showing the light-emitting diode control system according to an embodiment of the present invention.

[0019] Figure 1B Showing the Figure 1A detailed block diagram of the light-emitting diode control system.

[0020] Figure 2 Illustrating the formats of the brightness input data SI and the brightness output data SO.

[0021] HTP240216CN Page 3 / 6

[0022] Figure 3A Showing the formats of the brightness input data SI of the relevant light-emitting diode driver and the brightness output data SO with a substitution error status after the brightness input data SI is transmitted to the relevant light-emitting diode driver.

[0023] Figure 3B Showing another format of the brightness input data SI of the relevant light-emitting diode driver and the brightness output data SO with a substitution error status after the brightness input data SI is transmitted to the relevant light-emitting diode driver.

[0024]

Reference Signs

[0025] 100: Light-emitting diode control system

[0026] 11: Light-emitting diode array

[0027] 111: Light-emitting diode

[0028] 12: Light-emitting diode driver

[0029] 13: Light-emitting diode controller

[0030] SI: Brightness input data

[0031] SO: Brightness output data

[0032] SCK: Serial frequency

[0033] CS: Chip select signal

[0034] VLED: Supply power

[0035] W: Write

[0036] R: Read

[0037] Reg: Register

[0038] duty: Duty cycle

[0039] ch: Channel

[0040] lsb: Least Significant Bit

[0041] msb: Most Significant Bit

[0042] CRC: Cyclic Redundancy Check Code Detailed Implementation Manner

[0043] Figure 1A The block diagram of the light emitting diode (LED) control system 100 according to an embodiment of the present invention is shown. The light emitting diode control system 100 of this embodiment can be applied to in-vehicle applications and be used as the backlight of a liquid crystal display (LCD), but is not limited thereto.

[0044] HTP240216CN Page 4 / 6

[0045] In this embodiment, the light emitting diode control system 100 may include an LED array 11, which is composed of multiple LED channels, and each LED channel includes multiple light emitting diodes 111.

[0046] The light emitting diode control system 100 of this embodiment may include multiple LED drivers 12, which are connected in sequence to drive the corresponding LED channels respectively. The light emitting diode control system 100 may include an LED controller 13 (for example, a timing controller), which is used to send brightness data (for example, pulse width modulation (PWM) duty cycle) to the LED driver 12 to control the brightness of the light emitting diode 111.

[0047] In this embodiment, a synchronous serial communication interface (or specification), such as a Serial Peripheral Interface (SPI), is used between the LED controller 13 and the LED driver 12 as the LED driver interface to sequentially control the LED channels of the LED array 11 through the daisy chain-connected LED drivers 12. Among them, each LED driver 12 receives the brightness input data SI from the previous LED driver 12 (however, the first LED driver 12 receives the brightness input data SI from the LED controller 13), and each LED driver 12 sends the brightness output data SO to the next LED driver 12 (however, the last LED driver 12 sends the brightness output data SO back to the LED controller 13). The larger the number of light emitting diodes 111, the greater the bandwidth requirement.

[0048] As Figure 1AAs shown, the light-emitting diode controller 13 can generate a chip select signal CS, which is a serial peripheral interface (SPI) communication signal used to select (or activate) one of the light-emitting diode drivers 12 connected to the serial peripheral interface (SPI) bus. The light-emitting diode controller 13 can generate a serial clock (SCK), which is a serial peripheral interface (SPI) communication signal used to control the data input and output of the light-emitting diode driver 12, thereby synchronizing the data transmission between the light-emitting diode controller 13 and the light-emitting diode driver 12.

[0049] Figure 1B Display Figure 1A Detailed block diagram of the light-emitting diode control system 100. The light-emitting diodes 111 of the same channel are connected in parallel between the supply power VLED and the corresponding light-emitting diode driver 12. The first electrode (e.g., anode) of the light-emitting diode 111 is connected to the supply power VLED, and the second electrode (e.g., cathode) is connected to the corresponding light-emitting diode driver 12.

[0050] Generally speaking, the data transmission of serial peripheral interface (SPI) communication is operated through commands of independent read / write buffers. Figure 2 Illustrate the format (or fields) of the brightness input data SI and the brightness output data SO. The buffer is a small and fast storage device that can be located on pages 5 / 6 of the light-emitting diode controller HTP240216CN

[0051] 13 to store the data of the light-emitting diode controller 13 in real time. The read / write buffer can be used to store the data read or written by the light-emitting diode controller 13.

[0052] Serial peripheral interface (SPI) communication mainly transmits settings and pulse width modulation (PWM) duty cycles. The light-emitting diode controller 13 can obtain the error status in the light-emitting diode control system 100 through additional error status readings. Especially for in-vehicle applications, the safety is increased by providing measures to ensure the safety of driving operations and vehicle control.

[0053] However, if the number of light-emitting diodes 111 is large, the number of pulse width modulation (PWM) duty cycles required for the light-emitting diodes 111 also becomes very large. The additional error status readings will occupy additional bandwidth and affect the number of light-emitting diodes 111 that can be supported. The control process of the light-emitting diode controller 13 becomes more complex, and before sending a read error status command to read the error status (as Figure 2 illustrated), it is necessary to control the delay to ensure that each light-emitting diode driver 12 has received the pulse width modulation (PWM) duty cycle. At the same time, additional overhead data is also required.

[0054] According to one of the features of this embodiment, after the luminance input data SI is transmitted to the relevant light-emitting diode driver 12, the luminance input data SI is replaced with status data, such as an error status (sent back or fed back by the relevant light-emitting diode driver 12), which is finally read by the light-emitting diode controller 13 via other light-emitting diode drivers 12 without using an additional error status reading command. Figure 3A Shows the format (or fields) of the luminance input data SI of the relevant light-emitting diode driver 12 and the format (or fields) of the luminance output data SO with the replaced error status after the luminance input data SI is transmitted to the relevant light-emitting diode driver 12.

[0055] Due to the use of daisy chain connection, the luminance data is transmitted one by one, but the luminance data given to a certain light-emitting diode driver 12 is only valid for that light-emitting diode driver 12. After the light-emitting diode driver 12 receives the luminance data, the luminance data is no longer needed (or becomes invalid). Therefore, the luminance data can be replaced with other data, such as an error status, which can be received by the light-emitting diode controller 13 without affecting the normal data transmission between the light-emitting diode controller 13 and the light-emitting diode driver 12. Thereby, the control process is simplified and the bandwidth is reduced.

[0056] Figure 3B Shows the format (or fields) of the luminance input data SI of the relevant light-emitting diode driver 12 and another format (or fields) of the luminance output data SO with the replaced error status after the luminance input data SI is transmitted to the relevant light-emitting diode driver 12. A new command field can be added to represent different purposes for different commands to feedback data. The error status is sent once every few frames. As Figure 3B illustrated, the first luminance output data SO is used to send the error status of the first frame, and its HTP240216CN Page 6 / 6

[0057] The empty command sent by other frames (such as the second luminance output data SO illustrated) changes the data to 0 (no switching) to reduce the electromagnetic interference (EMI) effect caused by switching.

[0058] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the relevant art can make some changes or modifications to form equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as the content does not depart from the technical solution of the present invention, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A light emitting diode control system, characterized in that: Include: A light emitting diode array, comprising a plurality of light emitting diode channels, each light emitting diode channel comprising a plurality of light emitting diodes; A plurality of LED drivers are connected in sequence to drive corresponding LED channels respectively, and the plurality of LED channels are controlled in sequence by the plurality of LED drivers; and A light emitting diode controller, used for sending brightness data to the plurality of light emitting diode drivers, so as to control the brightness of the plurality of light emitting diodes; After the brightness input data is transmitted to the relevant LED driver, the brightness input data is replaced by the status data of the relevant LED driver, which is finally read by the LED controller via other LED drivers.

2. The light emitting diode control system according to claim 1, characterized in that: The plurality of LED channels are sequentially controlled by the plurality of LED drivers connected in daisy chain.

3. The light emitting diode control system according to claim 1, characterized in that: It further comprises a timing controller, which comprises the light emitting diode controller.

4. The light emitting diode control system according to claim 1, characterized in that: A synchronous serial communication interface is used between the LED controller and the LED driver as an interface of the LED driver.

5. The light emitting diode control system according to claim 4, characterized in that: The synchronous serial communication interface includes a serial peripheral interface.

6. The light emitting diode control system according to claim 1, characterized in that: Each LED driver receives brightness input data from the previous LED driver and each LED driver sends brightness output data to the next LED driver, whereas the first LED driver receives brightness input data from the LED controller and the last LED driver sends brightness output data back to the LED controller.

7. The light emitting diode control system according to claim 1, characterized in that: The status data contains the error status.

8. The light emitting diode control system according to claim 1, characterized in that: The replacement status data is eventually read by the LED controller without using an additional status read command.

9. The light emitting diode control system according to claim 1, characterized in that: The brightness input data is replaced by status data every several frames.

10. The light emitting diode control system according to claim 9, characterized in that: When the frame is not replaced with status data, the empty command is used, which changes the data to 0.

11. The light emitting diode control system according to claim 1, characterized in that: The brightness data includes a pulse width modulation duty cycle.

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