Multi-channel LED backlight system

Abstract

The utility model provides a multichannel light-emitting diode (LED) backlight system, which comprises a host chip, a plurality of constant-current control chips and LED lamp beads connected between one or more LED lamp bead current input pins of each constant-current control chip in the plurality of constant-current control chips and an LED load power supply voltage terminal of the LED backlight system, wherein a communication data input pin of a first-stage constant-current control chip in the plurality of constant-current control chips is connected to a communication data output pin of the host chip; the communication data output pin of the last-stage constant-current control chip in the plurality of constant-current control chips is connected to the communication data input pin of the host chip; communication data input pin and communication data output pin of each intermediate-stage constant-current control chip in the plurality of constant-current control chips are respectively connected to communication data output pin of previous-stage constant-current control chip of the intermediate-stage constant-current control chip and communication data input of next-stage constant-current control chip of the intermediate-stage constant-current control chip and feet.

Description

Technical Field

[0001] This utility model relates to the field of circuits, and in particular to a multi-channel LED backlight system. Background Technology

[0002] In traditional liquid crystal displays (LCDs), a high-density LED array composed of a large number of mini LED beads with a size on the order of 100 micrometers can be used as a backlight. The on / off state and brightness of these mini LED beads can be controlled individually, and local dimming technology can be combined to achieve precise light control for different areas of the screen. Utility Model Content

[0003] The multi-channel LED backlight system according to an embodiment of the present invention includes a host chip, multiple constant current control chips, and LED beads connected between one or more LED bead current input pins of each constant current control chip and the LED load power supply voltage terminals of the LED backlight system. The communication data input pin of the first-stage constant current control chip is connected to the communication data output pin of the host chip; the communication data output pin of the last-stage constant current control chip is connected to the communication data input pin of the host chip; and the communication data input pin and communication data output pin of each intermediate-stage constant current control chip are respectively connected to the communication data output pin of the preceding stage constant current control chip and the communication data input pin of the following stage constant current control chip.

[0004] In some embodiments, the chip power supply pin of the first-stage constant current control chip is connected to the chip power supply voltage terminal of the LED backlight system.

[0005] In some embodiments, the power supply pin of each intermediate-level constant current control chip in the plurality of constant current control chips is connected to the power supply pin of the preceding-level constant current control chip and to the power supply pin of the following-level constant current control chip.

[0006] In some embodiments, the power supply pin of the final stage constant current control chip is connected to the power supply pin of the preceding stage constant current control chip.

[0007] In some embodiments, the chip reference ground pin of each of the plurality of constant current control chips is connected to the circuit reference ground of the LED backlight system. Attached Figure Description

[0008] The present invention can be better understood from the following description of specific embodiments in conjunction with the accompanying drawings, wherein:

[0009] Figure 1 This is a schematic diagram illustrating an example structure of an LED backlight system according to an embodiment of the present invention.

[0010] Figure 2 It is shown in the figure. Figure 1 The diagram shows an example pin arrangement and internal structure of a constant current control chip. Detailed Implementation

[0011] The features and exemplary embodiments of various aspects of this utility model will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a comprehensive understanding of this utility model. However, it will be apparent to those skilled in the art that this utility model can be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of this utility model by illustrating examples of it. This utility model is by no means limited to any specific configuration set forth below, but covers any modifications, substitutions, and improvements to elements and components without departing from the spirit of this utility model. In the accompanying drawings and the following description, well-known structures and techniques are not shown in order to avoid causing unnecessary obscurity to this utility model. Furthermore, it should be noted that the term "connected to B" as used herein can mean "directly connected to B" or "indirectly connected to B via one or more other elements."

[0012] Figure 1 This is a schematic diagram illustrating an example structure of a multi-channel LED backlight system according to an embodiment of the present invention. Figure 1 As shown, the multi-channel LED backlight system 100 includes a host chip U0, constant current control chips U1 to Un (n is an integer greater than or equal to 2), and LEDs L1 to Lm (m is an integer greater than or equal to 2) connected between one or more LED current input pins of each constant current control chip U1 to Un and the LED load power supply voltage terminal VBL of the LED backlight system 100. Specifically: the communication data input pin of the first-stage constant current control chip U1 is connected to the communication data output pin of the host chip U0; the communication data output pin of the last-stage constant current control chip Un is connected to the communication data input pin of the host chip U0; and the communication data input pin and communication data output pin of each intermediate-stage constant current control chip Uk (k is an integer greater than or equal to 1 and less than or equal to n) are respectively connected to the communication data output pin of the preceding stage constant current control chip U(k-1) and the communication data input pin of the following stage constant current control chip U(k+1).

[0013] In the multi-channel LED backlight system 100 according to the present utility model embodiment, the host chip U0 can realize data communication with each constant current control chip through a single communication line, and can realize the control of brightness adjustment, on / off, startup timing, etc. of one or more channels of any constant current control chip through a single communication data input pin.

[0014] like Figure 1 As shown, in some embodiments, the chip power supply pin of the first-stage constant current control chip U1 is connected to the chip power supply voltage terminal VCC of the LED backlight system 100.

[0015] like Figure 1 As shown, in some embodiments, the power supply pin of each intermediate-level constant current control chip Uk is connected to the power supply pin of the preceding constant current control chip U(k-1) and to the power supply pin of the following constant current control chip U(k+1).

[0016] like Figure 1 As shown, in some embodiments, the power supply pin of the final constant current control chip Un is connected to the power supply pin of the preceding constant current control chip U(n-1).

[0017] like Figure 1 As shown, in some embodiments, the chip reference ground pin of each of the constant current control chips U1 to Un is connected to the circuit reference ground of the LED backlight system 100.

[0018] Figure 2 It is shown in the figure. Figure 1 The diagram shows an example pin arrangement and internal structure of a constant current control chip. Figure 2 As shown, the constant current control chip 200 can be used as any one of the constant current control chips U1 to Un, including a chip power supply pin (i.e., VCC pin), a chip reference ground pin (i.e., GND pin), one or more LED bead current input pins (e.g., LED0 pin to LED7 pin), a communication data input pin (i.e., DI pin), and a communication data output pin (i.e., DO pin).

[0019] like Figure 2 As shown, in some embodiments, the constant current control chip 200 includes a chip power supply module 202, an LED fault detection module 204, a constant current control module 206, a logic control module 208, a dimming control module 210, and a communication interface module 212, wherein:

[0020] The chip power supply module 202 is used to provide operating voltage to the various functional modules inside the constant current control chip 200 based on the chip power supply voltage from the outside.

[0021] The LED fault detection module 204 is used to detect whether each LED bead is faulty based on the voltage signal from the constant current control module 206, and outputs a logic signal to the logic control module 208 for corresponding logic control.

[0022] The constant current control module 206 is used to control the output current to be constant, feed back the voltage signal to the LED fault detection module 204, and output the logic signal to the logic control module 208 for corresponding logic control based on the dimming reference voltage signal and dimming duty cycle signal from the dimming control module 210, and the enable signal and timing logic signal from the logic control module 208.

[0023] The logic control module 208 is used to perform logic algorithm processing based on the logic signals from the LED fault detection module 204, the constant current control module 206, and the communication interface module 212, and outputs logic control signals to the constant current control module 206, the dimming control module 210, and the communication interface module 212 for corresponding control.

[0024] The dimming control module 210 is used to output the dimming reference voltage signal and dimming duty cycle signal required by the constant current control module 206 based on the logic control signal and pulse width modulation (PWM) duty cycle signal from the logic control module 208.

[0025] The communication interface module 212 is used to output a compiled logic control signal to the logic control module 210 based on the single-wire communication signal from the host chip U0, so that the logic control module 210 can perform corresponding logic control according to the requirements of the host chip U0, and output a single-wire communication signal to the host chip U0 based on the feedback signal from the logic control module 208.

[0026] like Figure 1 As shown, the working process of the LED backlight system 100 includes:

[0027] Phase 1: Once the chip supply voltage VCC reaches the startup voltage of the constant current control chips U1 to Un, the constant current control chips U1 to Un begin to start. After starting and receiving a single-wire communication signal, the constant current control chips U1 to Un enter Phase 2.

[0028] The second stage: After receiving the single-wire communication signal from the host chip U0, the constant current control chip U1 parses the data information matching its own device address according to the established communication protocol, configures its own parameters based on this data information, and individually controls one or more channels of LED beads for functions such as on / off and brightness adjustment. Constant current control chip U1 outputs the processed single-wire communication signal to the connected constant current control chip U2. After receiving the single-wire communication signal from constant current control chip U1, constant current control chip U2 parses the data information matching its own device address according to the established communication protocol, configures its own parameters based on this data information, and individually controls one or more channels of LED beads for functions such as on / off and brightness adjustment. This process continues, with each constant current control chip outputting a processed single-wire communication signal to the subsequent series-connected constant current control chips for corresponding control. The last constant current control chip in the series loop (i.e., the final-stage constant current control chip) returns the processed single-wire communication signal to the host chip U0, thus forming a closed-loop operation of the entire system.

[0029] Third stage: In the above two stages, when the chip supply voltage VCC drops below the undervoltage protection voltage of the constant current control chips U1 to Un, the constant current control chips U1 to Un shut down the self-powered system until the chip supply voltage VCC rises back to the start-up voltage of the constant current control chips U1 to Un, and then the cycle enters the first stage of operation.

[0030] In the LED backlight system 100 according to the present utility model embodiment, function configuration, brightness adjustment, and status reading can be realized through single-wire communication between the host chip U0 and the constant current control chips U1 to Un.

[0031] The main functional configurations include: resource allocation for analog dimming and PWM dimming control, allowing for flexible configuration of the accuracy of both dimming methods; adjustable output current rise and fall edges, facilitating electromagnetic interference (EMI) optimization; protection functions (including LED open-circuit protection, LED short-circuit protection, chip overheat current reduction protection, and chip overheat shutdown protection) that determine whether to shut down the affected channel and chip upon detecting an anomaly, preventing false triggering of protection functions; output enable for each channel, allowing for on / off control of any channel at any time; adjustable delay time for each channel relative to the synchronization signal, enabling flexible setting of the phase difference between channels to reduce noise and optimize EMI; adjustable trigger voltage thresholds and debouncing time for LED open-circuit and LED short-circuit protection to flexibly adapt to different application conditions; adjustable temperature point for chip overheat current reduction and the slope of current reduction with temperature to flexibly adapt to different application conditions; and adjustable temperature point for chip overheat shutdown protection to flexibly adapt to different application conditions.

[0032] Brightness adjustment includes real-time adjustment of the analog dimming current and PWM dimming duty cycle for each channel.

[0033] Status reading includes: reading whether the chip has experienced temperature protection status information. Specifically, it involves reading the status of each channel of the chip to check whether LED open-circuit protection or LED short-circuit protection has occurred. The above status reading function can be used for abnormal status location analysis.

[0034] In some embodiments, the host chip U0 can be implemented by, for example, the STM32 series chip from STMicroelectronics, and the constant current control chips U1 to Un can be implemented by, for example, the OB3818 chip from On-Bright Integrated Circuit Co., Ltd.

[0035] The features, structures, or characteristics described above can be combined in any suitable manner in one or more embodiments. Numerous specific details have been provided in the above description to give a full understanding of embodiments of the present invention. However, those skilled in the art will recognize that the technical solutions of the present invention can be practiced without one or more of the specific details described, or other methods, components, materials, etc., can be employed. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring the main technical concept of the present invention.

Claims

1. A multi-channel LED backlight system, characterized in that, The system includes a host chip, multiple constant current control chips, and one or more LED beads connected between the current input pin of each constant current control chip and the LED load power supply voltage terminal of the LED backlight system, wherein: The communication data input pin of the first-stage constant current control chip in the plurality of constant current control chips is connected to the communication data output pin of the host chip; The communication data output pin of the last-stage constant current control chip among the plurality of constant current control chips is connected to the communication data input pin of the host chip; and The communication data input pin and communication data output pin of each intermediate-level constant current control chip in the plurality of constant current control chips are respectively connected to the communication data output pin of the preceding-level constant current control chip and the communication data input pin of the following-level constant current control chip.

2. The multi-channel LED backlight system according to claim 1, characterized in that, The chip power supply pin of the first-stage constant current control chip is connected to the chip power supply voltage terminal of the LED backlight system.

3. The multi-channel LED backlight system according to claim 2, characterized in that, The power supply pin of each intermediate-level constant current control chip in the plurality of constant current control chips is connected to the power supply pin of the preceding-level constant current control chip and to the power supply pin of the following-level constant current control chip.

4. The multi-channel LED backlight system according to claim 2, characterized in that, The power supply pin of the final stage constant current control chip is connected to the power supply pin of the preceding stage constant current control chip.

5. The multi-channel LED backlight system according to claim 1, characterized in that, The chip reference ground pin of each of the plurality of constant current control chips is connected to the circuit reference ground of the LED backlight system.

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