Backlight driving chip and method, display device

Abstract

This invention discloses a backlight driving chip, method, and display device. According to an embodiment of the invention, the backlight driving chip includes a multi-channel driving array, which includes multiple driving channels; and a data distribution controller, which receives data packets containing channel information and driving information, and sends the corresponding driving information to the driving channel matching the channel information. According to the backlight driving chip, method, and display device of this invention, the refresh rate is no longer limited by the number of driving channels, enabling the matching of high refresh rate display requirements. Different driving channels are activated in staggered phases, reducing peak current and electromagnetic interference.

Description

Technical Field

[0001] This invention relates to the field of display driving technology, and in particular to a backlight driving chip and method, and a display device. Background Technology

[0002] In the field of liquid crystal displays, light-emitting diodes (LEDs) are commonly used as the light-emitting units of LED strings to provide backlight sources for backlight panels.

[0003] In existing technologies, backlight driving solutions typically use a large number of channels, with each channel corresponding to a backlight LED string. The backlight driving chip (circuit) provides current to each channel to drive the corresponding backlight LED string to emit light. Because a global serial data bus is used, brightness data must be written sequentially according to the channel order, and the data transmission time per frame is proportional to the number of channels. This limits the refresh rate of existing backlight driving solutions, making them unsuitable for the requirements of high refresh rate displays.

[0004] Therefore, there is a need for a new backlight driver chip and method, and a display device, that can solve at least one of the above problems. Summary of the Invention

[0005] In view of the above problems, the purpose of this invention is to provide a backlight driver chip and method, and a display device, so that the refresh rate is no longer limited by the number of driving channels and can meet the display requirements of high refresh rate.

[0006] According to one aspect of the present invention, a backlight driver chip is provided, comprising:

[0007] A multi-channel drive array, the multi-channel drive array including multiple drive channels; and

[0008] A data distribution controller receives data packets containing channel information and drive information, and sends the corresponding drive information to the drive channel that matches the channel information according to the channel information.

[0009] Optionally, after receiving the data packet, the data distribution controller parses the data packet to obtain the driving information;

[0010] The driver data in the driver information is written directly to the register of the corresponding driver channel.

[0011] Optionally, the drive channel includes a first buffer register and a second buffer register;

[0012] The first buffer register outputs the driving information of the current frame, and the second buffer register receives and buffers the driving information of the next frame. The first buffer register and the second buffer register switch driving information according to the global update signal, and for driving channels that have not received the driving information of the next frame, the output of the first buffer register is maintained.

[0013] Optionally, the drive channel includes:

[0014] Delay unit, the delay unit being used to provide a delay value,

[0015] After waiting for the delay value, the driving channel updates and displays the next frame of data.

[0016] Optionally, the drive channel includes an R drive channel, a G drive channel, and a B drive channel;

[0017] The R-drive channel, the G-drive channel, and the B-drive channel update and display the next frame of data according to their respective delay values. The start times for updating and displaying the next frame of data by the R-drive channel, the G-drive channel, and the B-drive channel are different to compensate for the response time difference between the R-drive channel, the G-drive channel, and the B-drive channel.

[0018] Optionally, the drive channel includes:

[0019] A duty cycle generator generates a duty cycle signal based on received drive information; the duty cycle generator has a built-in counter.

[0020] Optionally, different driving channels update and display the next frame of data according to the delay value, and the start time for updating and displaying the next frame of data is the same for different driving channels; or

[0021] The different driving channels update and display the next frame of data according to their respective delay values, and the start time for updating and displaying the next frame of data is different for the different driving channels; or

[0022] The multiple driving channels are divided into multiple driving groups, and each driving group includes at least one driving channel; the driving channels in the same driving group have the same start time for updating and displaying the next frame of data, while the driving channels in different driving groups have different start times for updating and displaying the next frame of data.

[0023] Optionally, the backlight driver chip further includes:

[0024] An adjustment unit adjusts the delay value corresponding to the drive channel based on at least one of temperature, peak current, printed circuit board layout, delay matching, and backlight string length.

[0025] According to another aspect of the present invention, a backlight driving method is provided, comprising:

[0026] Receive data packets containing channel information and drive information; and

[0027] Based on the channel information, the corresponding drive information is sent to the drive channel that matches the channel information.

[0028] According to another aspect of the present invention, a display device is provided, comprising:

[0029] Backlight; and

[0030] The backlight driver chip described above is connected to the backlight source to drive the backlight source.

[0031] The backlight driver chip, method, and display device provided by this invention send the corresponding driving information to the driving channel that matches the channel information according to the channel information. The data is no longer transmitted globally serially, and the data transmission time of a single frame is no longer proportional to the number of channels. As a result, the refresh rate is no longer limited by the number of driving channels and can meet the needs of high refresh rate display.

[0032] Furthermore, the staggered activation of different drive channels reduces peak current, thereby reducing power supply / ground noise, minimizing electromagnetic interference, and improving system stability.

[0033] Furthermore, to address the differences in LED response speed among the three RGB colors, different turn-on delays are set for the driving channels of each RGB color, ensuring that the three RGB colors reach their peak values ​​simultaneously, thereby improving the display effect.

[0034] Furthermore, it monitors its own temperature or the peak value of the output current, and then dynamically adjusts the delay of each drive channel, thereby automatically optimizing electromagnetic interference or temperature rise to the minimum during system operation.

[0035] Furthermore, by dynamically adjusting the phase (delay value), it can adapt to the differences in parasitic parameters caused by different printed circuit board layouts, LED string lengths, etc., thereby improving the system robustness.

[0036] Furthermore, the solution in this application ensures the synchronicity of updates at the instruction level and guarantees the asynchronicity of startup at the duty cycle waveform level. Attached Figure Description

[0037] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0038] Figure 1A schematic diagram of the structure of a backlight driver chip according to an embodiment of the present invention is shown;

[0039] Figure 2 A timing diagram of the delay mode of a backlight driver chip according to an embodiment of the present invention is shown;

[0040] Figure 3 This diagram illustrates the counting method of a backlight driver chip during one duty cycle according to an embodiment of the present invention.

[0041] Figure 4 A flowchart of a backlight driving method according to an embodiment of the present invention is shown;

[0042] Figure 5 A schematic diagram of the structure of a display device according to an embodiment of the present invention is shown. Detailed Implementation

[0043] Various embodiments of the invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale. Furthermore, certain well-known parts may not be shown in the drawings.

[0044] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. Many specific details of the invention, such as the structure, materials, dimensions, processing techniques, and methods of the components, are described below to provide a clearer understanding of the invention. However, as those skilled in the art will understand, the invention may be implemented without following these specific details.

[0045] It should be understood that when describing the structure of a component, when referring to a layer or region as being "above" or "on top of" another layer or region, it can mean that it is directly above the other layer or region, or that it contains other layers or regions between it and the other layer or region. Furthermore, if the component is flipped over, that layer or region will be located "below" or "under" the other layer or region.

[0046] The inventors conducted research on existing backlight driver chips (backlight driver solutions). They discovered the following technical bottlenecks in existing backlight driver chips:

[0047] 1) Data update latency: Brightness data needs to be written serially to all channels, and the refresh rate is limited in high-partition scenarios (usually <1kHz). Traditional backlight driver chips use a global serial data bus, and brightness data needs to be written sequentially according to the channel order. In high-partition scenarios (such as 1000+ partitions), the data transmission time per frame (Tdata) is directly proportional to the number of channels (N):

[0048] Tdata = N × Tbit;

[0049] Tbit represents the single-bit transmission time (typically ≥1μs). When N>1000, Tdata exceeds 1ms, limiting the refresh rate to below 1kHz, which cannot meet the requirements of high refresh rate displays (such as 360Hz field-sequence backlight).

[0050] 2) EMI (Electromagnetic Interference) and power consumption issues: Multi-channel PWM (Pulse Width Modulation Duty Cycle) synchronous switching causes instantaneous current peaks, leading to high-frequency electromagnetic interference (EMI exceeding standards) and local temperature rise.

[0051] 3) Insufficient flexibility: The fixed PWM turn-on edge cannot adapt to LED (Light-Emitting-Diode) strings with different response speeds (such as RGB color control). In traditional driver chips, all channels share the same clock source or trigger signal, resulting in strict synchronization of the rising edges of all PWM signals. For example, the turn-on times of an RGB three-color LED string are completely synchronized and cannot be staggered. However, differences in physical characteristics lead to differences in LED response speeds. Different colored LED chips (red, green, and blue) have different response times due to different materials. For example, the response time of a red LED is typically <100ns, while the response time of a blue / green LED can reach 200-500ns (due to differences in phosphorescent coating or band structure). In addition, factors such as the MOSFET switching speed and wiring capacitance of different channels further amplify the delay differences (driver circuit delay).

[0052] To address at least one of the aforementioned problems, the inventors have proposed a new backlight driver chip and method, a display device, and in particular a multi-channel backlight driver chip and a dynamic EMI suppression method.

[0053] According to one aspect of the present invention, a backlight driver chip is provided. Figure 1 A schematic diagram of the structure of a backlight driver chip according to an embodiment of the present invention is shown. Figure 1 As shown, the backlight driver chip according to an embodiment of the present invention includes a multi-channel driver array 100 and a data distribution controller 200.

[0054] Specifically, the multi-channel drive array 100 includes multiple drive channels.

[0055] The data distribution controller 200 receives data packets containing channel information and driver information, and sends the corresponding driver information to the driver channel that matches the channel information according to the channel information. Optionally, after receiving the data packet, the data distribution controller 200 parses the data packet to obtain the driver information; the driver data in the parsed driver information is directly written to the register of the corresponding driver channel, and the register may be a shadow register (ShadowBuffer).

[0056] Optionally, the driving channel includes a first buffer register and a second buffer register. The first buffer register outputs the driving information of the current frame. The second buffer register receives and buffers the driving information of the next frame. The first and second buffer registers switch driving information based on the global update signal. For driving channels that have not received the global update signal and the driving information of the next frame, the existing output of the first buffer register is maintained. The first buffer register is, for example, an active buffer used to output the current brightness. The second buffer register is, for example, a shadow buffer used to receive the new brightness. The global update signal is a control command that instructs all pixels of the entire display screen to perform a complete refresh and update simultaneously and synchronously. The generation of the global update signal is not necessarily at a fixed frequency; it can be triggered by specific system states and requirements. In this application, the generation of the global update signal can be set according to actual needs.

[0057] In an optional embodiment of the invention, the driving channel includes a delay unit. The delay unit is used to provide a delay value. After waiting for the delay value, the driving channel updates and displays the next frame of data.

[0058] Optionally, the driving channels include an R (Red) driving channel, a G (Green) driving channel, and a B (Blue) driving channel. The R, G, and B driving channels update and display the next frame of data according to their respective delay values. The start times for updating and displaying the next frame of data by the R, G, and B driving channels are different to compensate for the response time differences between the R, G, and B driving channels.

[0059] Optionally, the drive channel includes a duty cycle generator with a built-in counter. The duty cycle generator generates a duty cycle signal based on the received drive information.

[0060] Optionally, there are multiple driving channels. Different driving channels update and display the next frame of data according to their respective delay values, and the start time for updating and displaying the next frame of data is the same for different driving channels; or different driving channels update and display the next frame of data according to their respective delay values, and the start time for updating and displaying the next frame of data is different for different driving channels; or multiple driving channels are divided into multiple driving groups, and each driving group includes at least one driving channel; the start time for updating and displaying the next frame of data is the same for driving channels in the same driving group, and the start time for updating and displaying the next frame of data is different for driving channels in different driving groups.

[0061] Optionally, the backlight driver chip also includes an adjustment unit. The adjustment unit adjusts the delay value corresponding to the driving channel based on at least one of the following: temperature, peak current, printed circuit board layout, delay matching, and backlight string length. Optionally, delay matching refers to matching the delay with the liquid crystal driver chip; by precisely controlling the timing of the backlight and liquid crystal flipping to match, the backlight is turned on after the liquid crystal molecules have stabilized, thereby reducing display blur and improving the clarity of dynamic images. Optionally, the backlight driver chip incorporates a temperature monitoring module and a peak current detection module to monitor its own temperature and the peak value of the output current, and then dynamically adjusts the phase delay (delay value) of each driving channel to achieve electromagnetic interference suppression and temperature rise optimization.

[0062] In one specific embodiment of the present invention, the provided backlight driver chip is particularly suitable for MiniLED / MicroLED backlight driver systems, and is a backlight driver chip and control method that supports multi-channel independent brightness updates and PWM phase programmable configuration. The core architecture of the backlight driver chip includes a multi-channel driver array and a data distribution controller. Each (driving) channel in the multi-channel driver array includes an independent duty cycle (PWM) generator, a double-buffered register, and an independent data update delay register (delay unit). The duty cycle generator has a built-in counter. The double-buffered register includes a front buffer register for outputting the current brightness and a back buffer register (shadow register) for receiving the new brightness. After the data distribution controller parses the instruction, the data is directly written to the shadow register of the target (driving) channel, skipping unmodified (driving) channels. Optionally, the update delay counter is shared by all driving channels, and each driving channel has its own delay register. The display data of the driving channel is only updated when the delay register of the driving channel is equal to the delay counter value.

[0063] The backlight driver chip sends data by (driving) channel. Data transmission in each frame is not necessarily sequential; it can be sent individually or in multiple channels. The chip determines which (driving) channel is being transmitted using the `channel_mask` in the protocol packet, updating data according to the channel mask. For example, with 16 channels, the default `channel_mask=16'b0000_0000_0000_0000` and `channel_mask=16'b0000_0000_0000_0001` indicate that channels 1-15 out of 0-15 are being transmitted. According to this embodiment's backlight driver scheme, by using "updating by channel mask (channel information)" and "direct writing to the shadow register," the time bottleneck (Tdata=N×Tbit) caused by traditional serial shifting is broken. Theoretically, the refresh rate is no longer limited by the number of (driving) channels, matching high refresh rate displays.

[0064] The backlight driver chip updates data channel by channel. The duty cycle (PWM) on-edge of each channel can be configured via a register (data update delay register). After receiving the transmitted data packet, each channel waits for N time intervals before updating and displaying the data as a new frame. N is controlled by a register, and each channel corresponds to an update delay (duration) register. The delay value stored in the update delay register is based on the Nth clock cycle after the global frame synchronization signal.

[0065] Optionally, the backlight driver chip includes multiple delay modes, such as absolute delay mode, relative delay mode and group delay mode. Figure 2 A timing diagram illustrating the delay mode of a backlight driver chip according to an embodiment of the present invention is shown. Figure 2 As shown, in absolute delay mode, the on-time of each (driving) channel is relative to a common starting point (such as the frame start signal). In relative delay mode, the on-times of (driving) channels are staggered by a fixed step value (the staggered time between channels can also be variable). In group delay mode, multiple (driving) channels are divided into several groups (such as three groups for RGB), with synchronization within each group (the on-times of driving channels within the same group are the same), and phase separation between groups (the on-times of driving channels in different groups are different).

[0066] Furthermore, Figure 3 A schematic diagram illustrating the counting method of a backlight driver chip during one duty cycle according to an embodiment of the present invention is shown. (Combined with...) Figure 3 As shown, the delay values ​​of each drive channel are not exactly the same.

[0067] According to another aspect of the present invention, a backlight driving method is provided. Figure 4 A flowchart of a backlight driving method according to an embodiment of the present invention is shown. Figure 4 As shown, the backlight driving method according to an embodiment of the present invention includes the following steps:

[0068] In step S101, a data packet containing channel information and drive information is received;

[0069] In step S102, the corresponding drive information is sent to the drive channel that matches the channel information according to the channel information.

[0070] Specifically, the host sends data packets containing addresses, channel masks (channel information), brightness data (drive information), etc.

[0071] The backlight driver chip receives and parses data packets, and only writes the data to the shadow register of the driver channel specified by the channel mask.

[0072] The host sends a global update command (or the chip detects a specific condition, such as the end of a frame).

[0073] Each drive channel starts a countdown based on its own independent delay register (delay value) configuration. Only after the countdown ends is the content of the shadow register activated into the current register.

[0074] In one specific embodiment of the present invention, the host sends an instruction data packet containing a channel mask to the backlight driver chip. After parsing the data packet, the chip only writes the brightness data to the shadow buffer register of the corresponding driving channel. In response to a global update instruction, each driving channel starts a countdown based on its independently configured delay register value. After the countdown ends, the data in the shadow buffer register is activated to the front buffer register to update the PWM waveform. By staggering the PWM turn-on edges of each channel, the instantaneous current peak is reduced, and the PWM phase delay of each driving channel is dynamically adjusted according to the system operating state to optimize electromagnetic interference and temperature rise. Optionally, the channel mask uses a binary bit identifier, with each bit corresponding to the update state of a specific driving channel, and the data of channels that have not been changed retains the current value of the front buffer register.

[0075] According to another aspect of the present invention, a display device is provided. Figure 5 A schematic diagram of a display device according to an embodiment of the present invention is shown. Figure 5 As shown, the display device includes a backlight 20 and a backlight driver chip as described above. The backlight driver chip 10 is connected to the backlight 20 to drive the backlight 20.

[0076] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0077] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A backlight driving chip, comprising: a multi-channel driving array, the multi-channel driving array comprising a plurality of driving channels; and a data distribution controller, the data distribution controller receiving a data packet comprising channel information and driving information, and sending corresponding driving information to a driving channel matched with the channel information according to the channel information, wherein the channel information comprises a channel mask; the matched driving channel is determined according to the channel mask; different driving channels are turned on at different phases; after receiving the data packet, the data distribution controller parses the data packet to obtain the driving information; driving data in the driving information is directly written to a register of a corresponding driving channel; the driving channel comprises a first buffer register and a second buffer register; the first buffer register outputs driving information of a current frame, and the second buffer register receives and buffers driving information of a next frame; the first buffer register and the second buffer register trigger driving information switching according to a global update signal, and for a driving channel that has not received the driving information of the next frame, the output of the first buffer register is maintained. the driving channel comprises:

2. The backlight driving chip according to claim 1, wherein, a delay unit, the delay unit being configured to provide a delay value, wherein the driving channel updates and displays next frame data after waiting for the delay value. the driving channel comprises an R driving channel, a G driving channel and a B driving channel; 3. The backlight driving chip of claim 2, wherein, the R driving channel, the G driving channel and the B driving channel respectively update and display next frame data according to respective delay values, and the R driving channel, the G driving channel and the B driving channel update and display next frame data at different starting times to compensate for a response time difference between the R driving channel, the G driving channel and the B driving channel. the driving channel comprises:

4. The backlight driving chip of claim 2, wherein, a duty cycle generator, the duty cycle generator being configured to generate a duty cycle signal according to received driving information; and a counter built in the duty cycle generator. different driving channels respectively update and display next frame data according to the delay values, and different driving channels update and display next frame data at the same starting time; or 5. The backlight driving chip of claim 2, wherein, different driving channels respectively update and display next frame data according to respective delay values, and different driving channels update and display next frame data at different starting times; or a plurality of the driving channels are divided into a plurality of driving groups, and each driving group comprises at least one driving channel; driving channels in a same driving group update and display next frame data at the same starting time, and driving channels in different driving groups update and display next frame data at different starting times. the backlight driving chip further comprises: an adjustment unit, the adjustment unit being configured to adjust a delay value corresponding to the driving channel according to at least one of temperature, current peak value, printed circuit board layout, delay matching and backlight lamp string length.

6. The backlight driving chip of claim 2, wherein, 7.A backlight driving method, comprising: receiving a data packet comprising channel information and driving information; and sending corresponding driving information to a driving channel matched with the channel information according to the channel information. ​ ​ ​ The channel information includes a channel mask; the matched driving channel is determined according to the channel mask; and different driving channels are opened in phase difference; After receiving the data packet, the data distribution controller parses the data packet to obtain the driving information; The driving data in the driving information is directly written to the register of the corresponding driving channel; The driving channel includes a first buffer register and a second buffer register; The first buffer register outputs the driving information of the current frame, and the second buffer register receives and buffers the driving information of the next frame; the first buffer register and the second buffer register trigger driving information switching according to a global update signal, and for the driving channel that has not received the driving information of the next frame, the output of the first buffer register is maintained.

8. A display device, comprising: a backlight source; and a backlight driving chip as claimed in any one of claims 1-6, which is connected with the backlight source to drive the backlight source.

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