LED backlight driving system for preventing overvoltage damage of communication port

Abstract

The invention discloses an LED backlight driving system which comprises a serial communication link composed of a controller and a plurality of LED driving chips, and the controller is used as a host to send instruction data to the plurality of LED driving chips which are used as slaves; a controller and a plurality of LED driving chips; the controller and the plurality of LED driving chips form a serial communication link, and the controller is used as a host to send instruction data to the plurality of LED driving chips which are used as slaves; each LED driving chip is provided with a low-voltage communication port and a high-voltage power supply port, the low-voltage communication port is used for driving data transmission, and the high-voltage power supply port is used for supplying power to the LED driving chip; and a high-voltage clamping module is arranged in the LED driving chip, is directly connected with the low-voltage communication port and is used for clamping the voltage input into the low-voltage communication port below a preset voltage value and inputting the voltage input into the low-voltage communication port to the communication I / O module.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of LED backlight driving, in particular to an LED backlight driving system capable of preventing overvoltage damage of a communication port. BACKGROUND

[0002] In the field of LED backlight display, multi-partition local dimming backlight technology is increasingly popular. With the increasing number of partitions, backlight driving chips and LED lamps are often integrated on the same lamp panel, and power supplies and system control units are integrated on another panel, which are connected through a bus interface flying wire, as shown in the figure. FIG. 1 Due to the multi-partition of the backlight, there are multiple groups of corresponding bus interfaces. The bus interfaces are sequentially arranged with power supply signals, ground signals, communication signals and the like. Generally, the communication port is a low-voltage logic design I / O interface and cannot withstand high voltage. Once the bus is connected while being electrified, there is a probability of port misplacement. The low-voltage-resistant communication port is temporarily in contact with a higher voltage power supply or other port, resulting in overvoltage damage of the communication port of the driving chip. Especially in the current application scenarios of many lamp strips, the frequency of bus connection is very high, resulting in many lamp panels damaged by overvoltage, causing great cost waste.

[0003] Therefore, it can be seen that a new form of communication port of an LED backlight driving system is needed in the prior art, so that the LED driving chip in the LED backlight driving system can have the function of preventing overvoltage damage. SUMMARY

[0004] The technical purpose of the application is to provide an LED backlight driving system, wherein the LED driving chip in the LED backlight driving system can have the function of preventing overvoltage damage.

[0005] Based on the above technical purpose, the application provides an LED backlight driving system, which comprises a controller and a plurality of LED driving chips. The controller and the plurality of LED driving chips constitute a serial communication link, and the controller sends instruction data to the plurality of LED driving chips as slaves.

[0006] Each of the LED driving chips is provided with a low-voltage communication port and a high-voltage power supply port. The low-voltage communication port is used for driving data transmission, and the high-voltage power supply port is used for supplying power to the LED driving chip.

[0007] The LED driving chip is internally provided with a high-voltage clamping module. The high-voltage clamping module is directly connected to the low-voltage communication port, so as to clamp the voltage input to the low-voltage communication port below a predetermined voltage value, and then input the voltage input to the low-voltage communication port to the communication I / O module.

[0008] In one embodiment, the high-voltage clamping module is a high-voltage NMOS device, a drain of the high-voltage NMOS device is connected to a low-voltage communication port, and a source of the high-voltage NMOS device is connected to a communication I / O module.

[0009] In one embodiment, a clamping voltage value is determined by setting a gate voltage of the high-voltage NMOS device.

[0010] In one embodiment, the controller and the LED driving chip are respectively arranged on two circuit boards, and wires are used to connect the two circuit boards.

[0011] In one embodiment, each of the LED driving chips has a plurality of LED driving channel pins, and the LED driving channel pins are used to connect LED lamp strings to directly control light emission of the LED lamp strings.

[0012] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. BRIEF DESCRIPTION OF DRAWINGS

[0013] The accompanying drawings are included to provide a further understanding of the present application, and are incorporated in and constitute a part of the specification, illustrate embodiments of the present application, and together with the description serve to explain the present application, but are not intended to limit the present application. In the drawings:

[0014] FIG. 1 is a schematic diagram of a prior art LED backlight panel structure;

[0015] FIG. 2 is a schematic diagram of an LED driving chip structure of the present application;

[0016] FIG. 3 is a schematic diagram of a high-voltage clamping module structure of the LED driving chip of the present application. DETAILED DESCRIPTION

[0017] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings.

[0018] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as a second element, component, area, layer, or portion. And when a second element, component, area, layer, or portion is discussed, it does not imply that the first element, component, area, layer, or portion necessarily exists in this invention.

[0019] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below,” “under,” or “below” other elements or features will be oriented “above” other elements or features. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0020] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0021] The LED backlight driving system of the present invention includes: a controller HOST and a plurality of LED driver chips; the controller HOST and the plurality of LED driver chips form a serial communication link, wherein the controller acts as the master to send instruction data to the plurality of LED driver chips acting as slaves.

[0022] Each of the LED driver chips is provided with a low-voltage communication port and a high-voltage power supply port. The low-voltage communication port is used to drive data transmission, and the high-voltage power supply port is used to supply power to the LED driver chip.

[0023] Each of the LED driver chips has multiple LED driver channel pins, which are used to connect to LED strings to directly control the light emission of the LED strings.

[0024] like FIG. 2 As shown, the LED driver chip of this invention has a high-voltage clamping module internally. This module is directly connected to the low-voltage communication port to clamp the voltage input to the low-voltage communication port below a predetermined value before inputting the voltage to the communication I / O module. The high-voltage clamping module prevents overvoltage damage to the communication I / O module caused by accidental connection of the low-voltage communication port to a high-voltage power supply.

[0025] like FIG. 3 As shown, in this embodiment, the high-voltage clamping module is a high-voltage NMOS device. The drain of the high-voltage NMOS device is connected to the low-voltage communication port, the source of the high-voltage NMOS device is connected to the communication I / O module, and the gate of the high-voltage NMOS device is connected to the clamping voltage Vclp. Therefore, the source voltage is clamped at the clamping voltage Vclp minus the threshold voltage Vth. The threshold voltage Vth is a parameter of the high-voltage NMOS device itself. By setting the clamping voltage Vclp, the withstand voltage of the low-voltage communication port of the LED driver chip can be set to the highest withstand voltage allowed by the system. This prevents overvoltage damage to the communication I / O module even if the low-voltage communication port is mistakenly connected to a high-voltage power supply.

[0026] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. An LED backlight driving system, characterized in that: The LED backlight driving system includes: a controller and multiple LED driver chips; the controller and the multiple LED driver chips form a serial communication link, in which the controller, as the master, sends instruction data to the multiple LED driver chips, which are slaves; The controller and multiple LED driver chips; the controller and the multiple LED driver chips form a serial communication link, in which the controller, as the master, sends instruction data to the multiple LED driver chips, which are slaves; Each LED driver chip is provided with a low-voltage communication port and a high-voltage power supply port. The low-voltage communication port is used to drive data transmission, and the high-voltage power supply port is used to supply power to the LED driver chip. The LED driver chip has a high-voltage clamping module inside. The high-voltage clamping module is directly connected to the low-voltage communication port to clamp the voltage input to the low-voltage communication port below a predetermined voltage value, and then input the voltage input to the low-voltage communication port to the communication I / O module.

2. The LED backlight driving system according to claim 1, characterized in that, The high-voltage clamping module is a high-voltage NMOS device. The drain of the high-voltage NMOS device is connected to a low-voltage communication port, and the source of the high-voltage NMOS device is connected to a communication I / O module.

3. The LED backlight driving system according to claim 2, characterized in that, The clamping voltage value is determined by setting the gate voltage of the high-voltage NMOS device.

4. The LED backlight driving system according to claim 1, characterized in that, The controller and the LED driver chip are respectively mounted on two circuit boards, which are connected by wires.

5. The LED backlight driving system according to claim 1, characterized in that, Each of the LED driver chips has multiple LED driver channel pins, which are used to connect to LED strings to directly control the light emission of the LED strings.

6. An LED backlight panel, characterized in that, The LED backlight panel uses an LED backlight driving system as described in any one of claims 1-5 to drive the LEDs.

7. A display device, characterized in that, The display device includes an LED backlight panel as described in claim 6.

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