Backlight system and LED driving chip thereof

Abstract

A backlight system and an LED driving chip thereof are provided. The LED driving chip used in the backlight system is configured to, for any one LED channel in the LED driving chip: generate channel voltage feedback information of the LED channel based on an LED negative terminal voltage of the LED channel, a first threshold voltage, and channel state indication information of the LED channel; and generate the channel state indication information of the LED channel based on the LED negative terminal voltage of the LED channel, a second threshold voltage, and driving voltage indication information indicating that an LED driving voltage of the backlight system has approached or exceeded an expected voltage. The second threshold voltage is lower than the first threshold voltage. The driving voltage indication information is generated by a controller in the backlight system based on the channel voltage feedback information of the LED channel. The channel state indication information of the LED channel indicates whether the LED channel has an abnormality. The channel voltage feedback information of the LED channel indicates a comparison relationship between the LED negative terminal voltage of the LED channel and the first threshold voltage or that the LED channel has the abnormality.

Description

Technical Field

[0001] This invention relates to the field of circuits, and more specifically to a backlight system and its LED driver chip. Background Technology

[0002] With the development of light-emitting diode (LED) display devices, miniLED display technology is gaining increasing popularity. MiniLED display technology allows for independent brightness adjustment and control of different miniLEDs based on the displayed image, thereby improving image quality. Since a backlight system contains a large number of miniLEDs, abnormalities are inevitable during manufacturing or use. Failure to detect abnormal miniLEDs in a timely manner may affect the stable operation of the entire backlight system. Summary of the Invention

[0003] According to an embodiment of the present invention, an LED driver chip used in a backlight system is configured to, for any LED channel in the LED driver chip: generate channel voltage feedback information for the LED channel based on the LED negative terminal voltage, a first threshold voltage, and channel status indication information of the LED channel; and generate channel status indication information for the LED channel based on the LED negative terminal voltage, a second threshold voltage, and driving voltage indication information indicating that the LED driving voltage of the backlight system is close to or exceeds a expected voltage. The second threshold voltage is lower than the first threshold voltage. The driving voltage indication information is generated by a controller in the backlight system based on the channel voltage feedback information of the LED channel. The channel status indication information of the LED channel indicates whether there is an abnormality in the LED channel. The channel voltage feedback information of the LED channel indicates the comparison between the LED negative terminal voltage and the first threshold voltage of the LED channel or whether there is an abnormality in the LED channel.

[0004] A backlight system according to an embodiment of the present invention includes: one or more of the aforementioned LED driver chips; and a controller configured to receive channel voltage feedback information of each LED channel of each of the one or more LED driver chips, determine, based on the received channel voltage feedback information, whether the number of LED channels in the backlight system with LED negative terminal voltage higher than a first threshold voltage is higher than a first predetermined value or whether the number of control regions in which the LED negative terminal voltage of each of the LED channels is higher than the first threshold voltage is higher than a second predetermined value, and if the determination result is yes, send driving voltage indication information indicating that the LED driving voltage of the backlight system has approached or exceeded the expected voltage to each of the one or more aforementioned LED driver chips. Attached Figure Description

[0005] The invention can be better understood from the following description of specific embodiments of the invention in conjunction with the accompanying drawings, wherein:

[0006] Figure 1 A connection diagram of a backlight system using miniLEDs is shown.

[0007] Figure 2 It shows the use in Figure 1 The diagram shows a circuit diagram of the channel voltage determination circuit in the LED driver chip.

[0008] Figure 3 It shows Figure 1 The diagram shown illustrates the control mechanism of the controller for any LED driver chip.

[0009] Figure 4 An example flowchart of a control method for use in a backlight system according to an embodiment of the present invention is shown.

[0010] Figure 5 An example diagram of an information feedback mechanism used in a backlight system according to an embodiment of the present invention is shown.

[0011] Figure 6 A schematic block diagram of an LED driver chip used in a backlight system according to an embodiment of the present invention is shown.

[0012] Figure 7 A schematic block diagram of another LED driver chip used in a backlight system according to an embodiment of the present invention is shown. Detailed Implementation

[0013] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a comprehensive understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific configuration and algorithm presented below, but covers any modifications, substitutions, and improvements to elements, components, and algorithms without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description in order to avoid unnecessarily obscuring the invention. Furthermore, it should be noted that the term "A connected to B" as used herein can mean "A and B are directly connected" or "A and B are indirectly connected via one or more other elements."

[0014] Figure 1 A connection diagram of a backlight system using miniLEDs is shown. Figure 1In the backlight system 100 shown, the controller 102 can control multiple LED driver chips or multiple control areas via multiple single-wire buses (as an example). Figure 1 Two control areas are shown; each single-wire bus couples one LED driver chip; each control area includes one or more LED driver chips; each LED driver chip includes one or more LED driver chips, which are arranged in series with signal output ports and signal input ports connected and finally return to controller 102; each LED driver chip has one signal input port and one signal output port, and may contain multiple LED driver circuits; controller 102 controls the output voltage of power supply 104 (i.e., LED driving voltage of backlight system 100) according to the feedback information of each LED driver chip.

[0015] Figure 2 It shows the use in Figure 1 The diagram shows a schematic of the channel voltage determination circuit in an LED driver chip. Figure 2 As shown, when an LED channel is in the on state, the driving current flows through the LED in the LED channel and generates a voltage drop across the LED. At this time, the LED driver chip 200 can determine the working state of the LED based on the LED negative terminal voltage VLED. Typically, the specifications and characteristics of LEDs used in the same backlight system are very similar, and the voltage drops across these LEDs are distributed within a small range. When all LEDs are working normally, each LED driver chip can generate channel voltage feedback information that compares the LED negative terminal voltage VLED of the corresponding LED channel with a preset voltage and transmit the channel voltage feedback information to the controller 102.

[0016] Figure 3 It shows Figure 1 The diagram shown illustrates the control mechanism of the controller for any LED driver chip. Figure 3 As shown, for any LED driver chip, the controller 102 sends a command data packet to the LED driver chip via a single-wire bus. After receiving the command data packet, the LED driver chip adds its own channel voltage feedback information to the command data packet and sends the command data packet to the next-level LED driver chip or controller. The command data packet containing the channel voltage feedback information of each level of LED driver chip is finally transmitted back to the controller 102. After receiving the command data packet transmitted back by the LED driver chip, the controller 102 can control the power supply 104 to change the LED driving voltage based on the channel voltage feedback information contained in the command data packet, so that each LED channel operates near the corresponding expected voltage.

[0017] exist Figure 1In the backlight system 100 shown, when an LED in any LED channel malfunctions, its negative terminal voltage VLED may also malfunction. Since the LED driver chip does not know whether the LED driving voltage is within the normal range when determining that the LED negative terminal voltage VLED is abnormal, it cannot accurately determine whether the abnormality is caused by the LED malfunction or by an abnormal LED driving voltage. If the LED negative terminal voltage VLED of one or more LED channels is too low (e.g., due to an open circuit or other malfunction in the LED), the controller 102 may mistakenly interpret this as insufficient LED driving voltage, thereby controlling the power supply 104 to increase the LED driving voltage. This results in the actual LED driving voltage being much higher than the required LED driving voltage, causing both efficiency loss and reduced system reliability.

[0018] In view of the above, a control mechanism for use in a backlight system according to an embodiment of the present invention is proposed, wherein the controller can generate driving voltage indication information indicating that the LED driving voltage has approached or exceeded the expected voltage based on the channel voltage feedback information transmitted back by each LED driver chip and send it to each LED driver chip. Each LED driver chip can determine, based on the driving voltage indication information, whether the abnormality of the LED negative terminal voltage of the corresponding LED channel is caused by an LED abnormality or by an abnormality of the LED driving voltage, and can provide channel voltage feedback information and / or channel status indication information to the controller based on the determination result.

[0019] Figure 4 An example flowchart of a control method for use in a backlight system according to an embodiment of the present invention is shown. Figure 4 As shown, the control method 400 used in the backlight system includes: S402, each LED driver chip in the backlight system generates channel voltage feedback information based on the LED negative terminal voltage of its own LED channel, a first threshold voltage, and channel status indication information, and transmits the channel voltage feedback information to the controller in the backlight system; S404, the controller in the backlight system determines, based on the received channel voltage feedback information, whether the number of LED channels in the backlight system with LED negative terminal voltage higher than the first threshold voltage is higher than a first predetermined value or whether the number of control areas in which the LED negative terminal voltage of each LED channel is higher than the first threshold voltage is higher than a second predetermined value, and if the determination result is yes, sends driving voltage indication information indicating that the LED driving voltage has approached or exceeded the expected voltage to each LED driver chip in the backlight system; S406, after receiving the driving voltage indication information, each LED driver chip in the backlight system generates channel status indication information indicating whether there is an abnormality in the LED channel by combining the LED negative terminal voltage of its own LED channel.

[0020] exist Figure 4 In the control method 400 shown for use in a backlight system, each LED driver chip in the backlight system, upon receiving the driving voltage indication information, can determine whether there is an abnormality in its own LED channel by combining the negative terminal voltage of its own LED channel (i.e., determining whether there is an abnormality in the LED channel). Therefore, when there is an abnormality in its own LED channel, this situation can be included in the channel voltage feedback information and notified to the controller in the backlight system. This avoids the controller in the backlight system mistakenly believing that the LED driving voltage is insufficient and controlling the power supply to increase the LED driving voltage. In this way, the situation where the actual provided LED driving voltage is much higher than the actual required LED driving voltage can be avoided, thereby avoiding efficiency loss and improving the reliability of the system.

[0021] Figure 5 An example diagram of an information feedback mechanism used in a backlight system according to an embodiment of the present invention is shown. Figure 5 As shown, when the LED driver chips at each level in the backlight system receive an instruction data packet containing feedback information from the previous one or more LED driver chips, they add their own feedback information to the instruction data packet and then pass the instruction data packet to the next level LED driver chip or controller in the backlight system.

[0022] Figure 6 A circuit diagram of an LED driver chip used in a backlight system according to an embodiment of the present invention is shown. Figure 6 As shown, the LED driver chip 600 used in the backlight system is configured to, for any LED channel in the LED driver chip: generate channel voltage feedback information S1x based on the LED negative terminal voltage of the LED channel, the first threshold voltage Vref1, and the channel status indication information S2x of the LED channel; and generate channel status indication information S2x based on the LED negative terminal voltage of the LED channel, the second threshold voltage Vref2, and the drive voltage indication information VBL_OK indicating that the LED driving voltage of the backlight system is close to or exceeds the expected voltage. Here, the drive voltage indication information VBL_OK is generated by the controller in the backlight system based on the channel voltage feedback information S1x of the LED channel. The channel status indication information S2x of the LED channel indicates whether there is an abnormality in the LED channel (i.e., whether there is an abnormality in the LED in the LED channel). The channel voltage feedback information S1x of the LED channel indicates the comparison relationship between the LED negative terminal voltage and the first threshold voltage Vref1 of the LED channel or whether there is an abnormality in the LED channel.

[0023] like Figure 6As shown, in some embodiments, the LED driver chip 600 can generate first voltage information of the LED channel by comparing the LED negative terminal voltage of the LED channel with the first threshold voltage Vref1, and generate channel voltage feedback information S1x of the LED channel by performing logical operations on the first voltage information of the LED channel and the channel state indication information S2x (for example, the channel voltage feedback information S1x can be generated by performing a logical AND operation on the result of the logical inverse operation of the channel state indication information S2x and the first voltage information).

[0024] like Figure 6 As shown, in some embodiments, the LED driver chip 600 can generate second voltage information of the LED channel by comparing the LED negative terminal voltage of the LED channel with the second threshold voltage Vref2, and generate channel state indication information S2x of the LED channel by performing logical operations on the second voltage information of the LED channel and the driving voltage indication information VBL_OK (for example, the channel state indication information S2x can be generated by performing a logical AND operation on the second voltage information and the driving voltage indication information VBL_OK).

[0025] like Figure 6 As shown, in some embodiments, the backlight system 100 employs... Figure 6 When the LED driver chip 600 is in its initial stage of operation, the controller 102 generates a drive voltage indication information VBL_OK = 0 before receiving channel voltage feedback information. At this time, the second voltage information is masked (the channel status indication information S2x is always 0), and the channel voltage feedback information S1x only contains the first voltage information regarding the comparison between the LED negative terminal voltage and the first threshold voltage Vref1. After the LED drive voltage reaches or exceeds the expected voltage, the controller 102 generates a drive voltage indication information VBL_OK = 1, and the LED driver chip 600 generates the channel status indication information S2x. If the LED negative terminal voltage is less than the second threshold voltage Vref2, the channel status indication information S2x will keep the channel voltage feedback information S1x constant at 0. It should be noted that when the drive voltage indication information VBL_OK = 1, the LED negative terminal voltage being less than the second threshold voltage Vref2 indicates an abnormality in the LED channel. At this time, the first voltage information is masked, so that the controller 102 does not need to consider this LED channel when adjusting the LED drive voltage with the power supply 104 later.

[0026] Figure 7 A schematic block diagram of another LED driver chip used in a backlight system according to an embodiment of the present invention is shown. Figure 7As shown, the LED driver chip 700 used in the backlight system includes a data input unit 702, voltage judgment units 704-1 to 704-M (M is an integer greater than or equal to 1), an information aggregation unit 706, a logic operation unit 708, and a data output unit 710. The data input unit 702 is configured to receive instruction data packets from the controller in the backlight system or the previous-level LED driver chip. Each of the voltage judgment units 704-1 to 704-M is configured to determine whether the negative terminal voltage of the corresponding LED channel is higher than a first and / or a second threshold voltage and generate channel voltage feedback information and / or channel status indication information based on the judgment result (see [link to implementation details]). Figure 6 The LED driver chip 600 is described; the information aggregation unit 706 is configured to generate drive voltage feedback information of the LED driver chip 700 based on channel voltage feedback information from voltage judgment units 704-1 to 704-M, and / or generate channel status feedback information of the LED driver chip 700 based on channel status indication information from voltage judgment units 704-1 to 704-M; the logic operation unit 708 is configured to add the drive voltage feedback information and / or channel status feedback information of the LED driver chip 700 to the instruction data packet by performing logical operations on the drive voltage feedback information and / or channel status feedback information of the LED driver chip 700 with corresponding information in the instruction data packet; the data output unit 710 is configured to send the instruction data packet to the controller or the next-level LED driver chip in the backlight system.

[0027] like Figure 7 As shown, in some embodiments, the LED driver chip 700 can receive a first instruction data packet from a controller in the backlight system or a previous-level LED driver chip, add the driving voltage feedback information of the LED driver chip to the first instruction data packet, and send the first instruction data packet to the next-level LED driver chip or controller in the backlight system. For example, the LED driver chip 700 can add the driving voltage feedback information of the LED driver chip to the first instruction data packet by performing logical operations on the driving voltage feedback information of the LED driver chip and the corresponding information in the first instruction data packet.

[0028] like Figure 7As shown, in some embodiments, the LED driver chip 700 can receive a second instruction data packet containing drive voltage indication information from a controller in the backlight system or a previous-level LED driver chip, add at least one of the drive voltage feedback information and channel status feedback information of the LED driver chip to the second instruction data packet, and send the second instruction data packet to the next-level LED driver chip or controller in the backlight system. For example, the LED driver chip 700 can add at least one of the drive voltage feedback information and channel status feedback information of the LED driver chip to the second instruction data packet by performing a logical operation between at least one of the drive voltage feedback information and channel status feedback information of the LED driver chip and the corresponding information in the second instruction data packet.

[0029] This invention can be implemented in other specific forms without departing from its spirit and essential characteristics. For example, the algorithm described in a particular embodiment can be modified without departing from the basic spirit of the invention. Therefore, the present embodiments are to be regarded as exemplary rather than limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and all changes falling within the meaning and scope of the claims and their equivalents are thus included within the scope of the invention.

Claims

1. An LED driver chip for use in a backlight system, configured for any one of the LED channels in the LED driver chip: Based on the LED negative terminal voltage, the first threshold voltage, and the channel status indication information of the LED channel, channel voltage feedback information of the LED channel is generated; and Based on the LED negative terminal voltage of the LED channel, the second threshold voltage, and the driving voltage indication information indicating that the LED driving voltage of the backlight system has approached or exceeded the expected voltage, channel status indication information of the LED channel is generated. in, If the second threshold voltage is lower than the first threshold voltage, the driving voltage indication information is generated by the controller in the backlight system based on the channel voltage feedback information of the LED channel. The channel status indication information of the LED channel indicates whether there is an abnormality in the LED channel. The channel voltage feedback information of the LED channel indicates the comparison between the negative terminal voltage of the LED channel and the first threshold voltage, or whether there is an abnormality in the LED channel. The LED driver chip is further configured to: generate driving voltage feedback information for the LED driver chip based on the channel voltage feedback information of each LED channel in the LED driver chip, and transmit the driving voltage feedback information of the LED driver chip to the controller in the backlight system; and The LED driver chip is further configured to: receive a first instruction data packet from the controller or the previous-level LED driver chip in the backlight system, add the driving voltage feedback information of the LED driver chip to the first instruction data packet, and send the first instruction data packet to the next-level LED driver chip or controller in the backlight system.

2. The LED driver chip for use in a backlight system according to claim 1, further configured as follows: First voltage information of the LED channel is generated by comparing the negative terminal voltage of the LED channel with the first threshold voltage; and By performing logical operations on the first voltage information of the LED channel and the channel status indication information of the LED channel, the channel voltage feedback information of the LED channel is generated.

3. The LED driver chip for use in a backlight system according to claim 1, further configured as follows: The second voltage information of the LED channel is generated by comparing the negative terminal voltage of the LED channel with the second threshold voltage. By performing logical operations on the second voltage information and the driving voltage indication information of the LED channel, the channel status indication information of the LED channel is generated.

4. The LED driver chip for use in a backlight system according to claim 1, further configured as follows: By performing logical operations on the driving voltage feedback information of the LED driver chip and the corresponding information in the first instruction data packet, the driving voltage feedback information of the LED driver chip is added to the first instruction data packet.

5. The LED driver chip for use in a backlight system according to claim 1, further configured as follows: Based on the channel status indication information of each LED channel in the LED driver chip, channel status feedback information of the LED driver chip is generated and transmitted to the controller in the backlight system.

6. The LED driver chip for use in a backlight system according to claim 5, further configured as follows: Receive a second instruction data packet containing the driving voltage indication information from the controller of the backlight system or the upstream LED driver chip; Add at least one of the driving voltage feedback information and channel status feedback information of the LED driver chip to the second instruction data packet; and The second instruction data packet is sent to the next-level LED driver chip or controller in the backlight system.

7. The LED driver chip for use in a backlight system according to claim 6, further configured as follows: By performing logical operations on at least one of the driving voltage feedback information and channel status feedback information of the LED driver chip with the corresponding information in the second instruction data packet, at least one of the driving voltage feedback information and channel status feedback information of the LED driver chip is added to the second instruction data packet.

8. A backlight system, comprising: One or more LED driver chips according to any one of claims 1 to 7; as well as The controller is configured to receive channel voltage feedback information from each LED channel of each LED driver chip in the one or more LED driver chips, and based on the received channel voltage feedback information, determine whether the number of LED channels in the backlight system with LED negative terminal voltage higher than a first threshold voltage is higher than a first predetermined value or whether the number of control regions in which the LED negative terminal voltage of each LED channel is higher than the first threshold voltage is higher than a second predetermined value, and if the determination result is yes, send driving voltage indication information to each LED driver chip in the one or more LED driver chips, indicating that the LED driving voltage of the backlight system has approached or exceeded the expected voltage.

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