LED display driving chip, turning voltage adjusting method, LED display device and electronic equipment

Abstract

The application discloses an LED display driving chip, a turning voltage adjusting method, an LED display device and electronic equipment. The LED display driving chip comprises a plurality of constant current output channels for driving a plurality of LED lamp strings respectively. Each constant current output channel is integrated with a data processing module, a comparison module and a bias adjusting module. The brightness representation signal representing the current display brightness can be generated according to the received gray data, and the value of the brightness representation signal is compared with a preset threshold value, so as to automatically adjust the bias voltage of the constant current driving module, thereby dynamically adjusting the turning voltage of the channel output end. The turning voltage is automatically adjusted by the internal circuit of the chip, the turning voltage is automatically adjusted to be high when the display brightness is low, the current consistency and display uniformity are ensured, the turning voltage is automatically adjusted to be low when the display brightness is high, the chip is ensured to be in the constant current interval, the power consumption is reduced, and the heat is reduced, so that the energy consumption and display quality are considered, and the applicability is high.

Description

Technical Field

[0001] This application relates to the field of LED display technology, specifically to an LED display driver chip, a transition voltage adjustment method, an LED display device, and an electronic device. Background Technology

[0002] LED displays are widely used in advertising, stage performances, transportation, and sports venues due to their high brightness, long lifespan, and energy-saving characteristics. With the rapid development of LED display technology and the deepening trend towards green and low-carbon practices, the energy consumption control requirements for LED display systems' driver chips are becoming increasingly stringent, with a desire to further reduce display power consumption.

[0003] To reduce power consumption in LED display systems and achieve energy savings, lower power supply voltages are typically used. This reduces the required breakover voltage for the LED display driver chip, which provides the constant current output channel for the LED strings. This can lead to lower current accuracy, resulting in poor current consistency at low grayscale levels. Conversely, increasing the breakover voltage at lower power supply levels can maintain current consistency at low grayscale levels, but it reduces the voltage drop across the driver chip at high grayscale levels, causing the output current to deviate from the constant current range and resulting in abnormal phenomena such as a dim display. Furthermore, excessively high breakover voltages in LED driver chips can also lead to excessive power consumption and heat generation. Therefore, current LED driver chip selection often struggles to simultaneously balance display quality and system power consumption. Summary of the Invention

[0004] This application provides an LED display driver chip, a transition voltage adjustment method, an LED display device, and an electronic device to solve the problems in the prior art.

[0005] According to one aspect of the present invention, an LED display driver chip is provided, comprising a plurality of constant current output channels, each constant current output channel driving a plurality of LED strings, wherein each constant current output channel comprises: a constant current driving module for providing a constant output current to the LED strings; a data processing module for acquiring grayscale data and processing it into a luminance characterization signal characterizing the display brightness; a comparison module for comparing the value of the luminance characterization signal with a preset threshold and outputting a comparison result; and a bias adjustment module for dynamically adjusting the bias voltage provided to the constant current driving module according to the comparison result, so as to adjust the transition voltage at the channel output terminal.

[0006] Optionally, the brightness characterization signal is selected from any one of the following signals: the duty cycle of the pulse width modulation signal driving the LED string, the count value of the display subframe formed by the grayscale data being scattered within a display frame, the calculated value of the duty cycle and the count value, the calculated value of the duty cycle and a constant, or the calculated value of the count value and a constant.

[0007] Optionally, when the comparison result indicates that the value of the brightness characterization signal is less than or equal to the preset threshold, the bias adjustment module adjusts the bias voltage to increase the transition voltage; and when the comparison result indicates that the value of the brightness characterization signal is greater than the preset threshold, the bias voltage adjusts the bias voltage to decrease the transition voltage.

[0008] Optionally, if the value of the brightness characterization signal is greater than the preset threshold, it indicates that the gray value of the current grayscale data is in the high gray range; if the value of the brightness characterization signal is less than or equal to the preset threshold, it indicates that the gray value of the current grayscale data is in the non-high gray range; and the display brightness of the display image corresponding to the grayscale data in the high gray range is higher than the display brightness of the display image corresponding to the grayscale data in the non-high gray range.

[0009] Optionally, the constant current drive module operates in the constant current region after each adjustment of the transition voltage, providing a constant output current to the LED string.

[0010] Optionally, each of the constant current output channels further includes: a memory for receiving and storing externally input grayscale data; and a threshold adjustment module for setting the specific value of the preset threshold, wherein the memory includes static random access memory, dynamic random access memory, or flash memory, and the LED display driver chip modifies the value of the registers in the chip via an external interface to modify the specific value of the preset threshold.

[0011] Optionally, the data processing module includes: a data conversion unit for converting the grayscale data into a pulse width modulation signal; a timer for timing the high-level duration of a single pulse in the pulse width modulation signal to obtain the duty cycle of the pulse width modulation signal; and a counter for counting the number of pulse groups of the pulse width modulation signal within a display frame, which is used as the count value of the display subframe, wherein the pulse group includes multiple consecutive pulses.

[0012] According to another aspect of the present invention, a transition voltage adjustment method is provided for adjusting the transition voltage at the output terminal of each constant current output channel in an LED display driver chip, wherein the transition voltage adjustment method includes: receiving grayscale data and processing it into a luminance characterization signal characterizing the display brightness; comparing the value of the luminance characterization signal with a preset threshold and outputting a comparison result; dynamically adjusting the bias voltage provided to the constant current driving module according to the comparison result to adjust the transition voltage; and controlling the constant current driving module to provide a constant current to the LED string driven by the constant current output channel according to the adjusted transition voltage.

[0013] Optionally, the brightness characterization signal is selected from any one of the following signals: the duty cycle of the pulse width modulation signal driving the LED string, the count value of the display subframe formed by the grayscale data being scattered within a display frame, the calculated value of the duty cycle and the count value, the calculated value of the duty cycle and a constant, or the calculated value of the count value and a constant.

[0014] Optionally, the step of dynamically adjusting the bias voltage provided to the constant current drive module according to the comparison result to adjust the transition voltage includes: when the comparison result indicates that the value of the brightness characterization signal is less than or equal to the preset threshold, adjusting the bias voltage to increase the transition voltage; when the comparison result indicates that the value of the brightness characterization signal is greater than the preset threshold, adjusting the bias voltage to decrease the transition voltage, wherein the value of the brightness characterization signal is greater than the preset threshold, indicating that the gray value of the current grayscale data is in the high gray range; the value of the brightness characterization signal is less than or equal to the preset threshold, indicating that the gray value of the current grayscale data is in the non-high gray range.

[0015] According to another aspect of the present invention, an LED display device is provided, comprising: the aforementioned LED display driver chip; and an LED array connected to the output terminal of the LED display driver chip, the LED array comprising a plurality of LED strings, the LED display driver chip comprising a plurality of constant current output channels, each of the constant current output channels corresponding to drive a plurality of the LED strings, wherein the LED display driver chip automatically adjusts the transition voltage at the output terminal of each constant current output channel according to real-time received grayscale data, so that the transition voltage changes with the display brightness.

[0016] According to another aspect of the present invention, an electronic device is provided, comprising: a control system; and an LED display device, the LED display device comprising an LED lamp array and the aforementioned LED display driver chip for driving the LED lamp array.

[0017] The LED display driver chip, transition voltage adjustment method, LED display device, and electronic device provided by this invention dynamically adjust the transition voltage at the output terminal of each constant current output channel based on externally input grayscale data. By setting a data processing module, a comparison module, and a bias adjustment module within each constant current output channel of the LED display driver chip, grayscale data is processed to generate a brightness characterization signal representing the current display brightness. The value of the brightness characterization signal is compared with a preset threshold to automatically adjust the bias voltage of the constant current driving module, thereby dynamically adjusting the transition voltage at the channel output terminal. This eliminates dependence on an external control system, allowing the chip to autonomously perform brightness analysis and transition voltage adjustment, achieving dynamic and autonomous adjustment of the transition voltage. This significantly reduces system complexity and development costs, and improves product integration and deployment flexibility.

[0018] Furthermore, this invention automatically adjusts the transition voltage based on the display brightness. When the value of the brightness representation signal is less than or equal to a preset threshold, it indicates that the grayscale value corresponding to the current grayscale data is in a non-high grayscale range. That is, when the display brightness is low, the transition voltage is automatically increased. This enhances the driving capability, ensures the consistency of current in each channel, and avoids display defects such as uneven brightness and flickering at low grayscale levels, thereby enhancing the image display effect when the grayscale value of the grayscale data is in the non-high grayscale range. Conversely, when the value of the brightness representation signal is greater than the preset threshold, it indicates that the grayscale value corresponding to the current grayscale data is in the high grayscale range. That is, when the display brightness is high, the transition voltage is automatically decreased. This ensures that the output current is always in a constant current range and also appropriately reduces the heat generation of the driver chip. Thus, by automatically adjusting the transition voltage, power consumption is reduced while ensuring display quality, improving system energy efficiency and achieving a dynamic balance between power consumption and display effect.

[0019] Furthermore, the brightness representation signal can take various forms. Among them, the duty cycle of the pulse width modulation signal driving the LED string and the count value of the scattered display subframes within a display frame are closely related to the display brightness. One of these two, or a combination thereof, or even a combination of these two with other parameters, can be used as the brightness representation signal, allowing the chip to flexibly adapt to different grayscale processing architectures and display driving methods. Simultaneously, the specific value of the preset threshold can be adjusted through registers, facilitating parameter optimization according to different application scenarios and enhancing the chip's versatility and configurability.

[0020] Furthermore, the LED display driver chip of this invention supports parallel operation of multiple constant current output channels, with each channel independently completing brightness sensing and transition voltage adjustment, making it suitable for driving large-scale LED light arrays. Combined with its energy-saving, stable, and adaptive characteristics, it can be widely used in scenarios with high requirements for both power consumption and display quality, such as advertising screens, stage screens, and traffic indicator screens, improving the energy efficiency level and user experience of terminal products and enhancing market competitiveness.

[0021] It should be noted that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the present invention. Attached Figure Description

[0022] Figure 1 A schematic structural diagram of an LED display device and an LED display driver chip according to an embodiment of the present invention is shown;

[0023] Figure 2 A constant current characteristic diagram of the transition voltage in an LED display driver chip according to an embodiment of the present invention is shown;

[0024] Figure 3A schematic structural block diagram of a constant current output channel according to an embodiment of the present invention is shown;

[0025] Figure 4 A schematic diagram of a portion of the circuit structure in a constant current drive module according to an embodiment of the present invention is shown;

[0026] Figure 5 A schematic flowchart of a transition voltage regulation method according to an embodiment of the present invention is shown. Detailed Implementation

[0027] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in various forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0028] Figure 1 A schematic structural diagram of an LED display device and an LED display driver chip according to an embodiment of the present invention is shown.

[0029] This invention provides an LED display device and an LED display driver chip that dynamically adjust the transition voltage based on the display brightness of the LED display screen, thereby achieving dynamic energy saving. For example... Figure 1 As shown, the LED display device includes an LED display driver chip 100 and an LED array connected thereto. The LED array includes multiple LED strings, each LED string consisting of multiple LED beads connected in series. The LED display driver chip 100 provides a constant current output current to the LED array to ensure stable light emission from the LED strings. The LED display driver chip 100 includes multiple constant current output channels 110, each constant current output channel 110 corresponding to drive several LED strings. Figure 1 In this configuration, each constant current output channel 110 is connected in parallel and connected to an LED string for independent control. The anode of each LED string is connected to the power supply voltage VCC, while the cathode is grounded through the corresponding constant current output channel 110, forming a complete circuit. When the LED display driver chip 100 is working, current flows from the power supply terminal through a string of LED beads into the LED display driver chip 100. During this process, the LED display driver chip 100 generates heat and consumes power.

[0030] Let LED1 represent an LED string connected to the output of a constant current output channel 110. This channel 110 includes a constant current drive module containing a constant current source A1, providing a constant output current Iout to the connected LED string LED1. Similarly, LED2 represents another LED string connected to the output of the corresponding constant current output channel 110. This channel's constant current drive module also includes a constant current source A2, providing a constant output current Iout to LED2. LEDn represents the nth LED string connected to the output of the corresponding constant current output channel 110. This channel's constant current drive module includes a constant current source An, providing a constant output current Iout to LEDn.

[0031] Since grayscale data can characterize display brightness, in this embodiment, each constant current output channel 110 in the LED display driver chip 100 automatically adjusts the transition voltage VDS at the output terminal of each constant current output channel 110 according to the real-time received grayscale data, so that the transition voltage VDS changes with the display brightness. The transition voltage VDS mentioned here, also known as the inflection point voltage, refers to the minimum voltage drop between the output terminal and ground required for the constant current output channel in the LED display driver chip to maintain a constant output current during normal operation. Figure 1 When the chip is working, current flows from the power supply terminal through the LED string and into the LED display driver chip 100. At this time, the voltage obtained by subtracting the forward voltage drop Vled of the LED string from the power supply voltage VCC is approximately equal to the channel voltage drop VIC across the constant current output channel 110 in the LED display driver chip. That is, VIC = VCC - Vled. VIC ≥ VDS must be ensured for the chip to output a constant current normally; that is, the channel voltage drop VIC must be greater than or equal to the breakover voltage VDS for the LED display driver chip 100 to maintain a constant current output.

[0032] In this embodiment, the transition voltage VDS is dynamically adjusted according to the display brightness to balance display performance and system power consumption. Specifically, the dynamic adjustment of the transition voltage can involve automatically decreasing the transition voltage VDS when the display brightness is high and automatically increasing the transition voltage VDS when the display brightness is low. The following describes the specific implementation of this adjustment. Figure 2 Detailed introduction.

[0033] Figure 2 A diagram illustrating the constant current characteristics of the transition voltage in an LED display driver chip according to an embodiment of the present invention is shown.

[0034] like Figure 2 As shown, the horizontal axis represents the channel voltage drop VIC, the vertical axis represents the output current Iout, and VDS represents the breakover voltage. Figure 2The diagram shows two different curves illustrating the relationship between the breakpoint voltage and the output current. For any breakpoint voltage, there is an inflection point on the curve. Before the inflection point, in the non-constant current region, the output current Iout increases with the channel voltage drop VIC. When the voltage reaches the inflection point, the output current Iout tends to stabilize, and then enters the constant current region, where the output current Iout remains constant and no longer changes with the channel voltage drop VIC. The voltage at the output current inflection point on the curve is the inflection voltage or breakpoint voltage VDS. For the blue curve, its breakpoint voltage VDS = V1, while for the red curve, its breakpoint voltage VDS = V2, where V2 > V1.

[0035] Combination Figure 1 When the display brightness is low and the grayscale value of the grayscale data is in the low-to-medium gray range (or not in the high gray range), the current on the LED string is small, resulting in a low Vled voltage. According to VIC=VDD-Vled, the channel voltage drop VIC on the LED display driver chip 100 is high at this time. For example, VIC1 corresponds to point A, and the output current is I1. Regardless of the transition voltage VDS, the output current Iout is in the constant current range. At this time, when the transition voltage VDS is low, for example, VDS=V1, the current accuracy will deteriorate. To ensure the consistency of the low-to-medium gray display, the transition voltage VDS needs to be increased, i.e., VDS=V2, for better display effect. Therefore, in this embodiment, when the display brightness is low and the grayscale value of the grayscale data is in the low-to-medium gray range, the transition voltage VDS needs to be increased.

[0036] When the display brightness is high and the grayscale value of the grayscale data is in the high gray range, the current in the LED string increases, the Vled voltage increases, and the channel voltage drop VIC decreases, for example, to VIC2. At this time, if the breakover voltage is set high, i.e., VDS=V2, according to... Figure 2 The constant current characteristic curve shows that when VIC = VIC2, at point B, the output current Iout drops to I2, which is no longer in the constant current range, causing the LED display brightness to dim. Therefore, when displaying a high grayscale image on the LED, VDS is reduced so that VDS = V1. Then, according to the curve, when VIC = VIC2, at point C, the output current is I1, which remains within the constant current range. Therefore, in this embodiment, when the display brightness is high and the grayscale value of the grayscale data is in the high grayscale range, the breakover voltage VDS needs to be lowered.

[0037] Therefore, the constant current output channel in this embodiment operates in the constant current region after each adjustment of the transition voltage VDS, providing a constant output current to the corresponding LED string. Furthermore, it ensures display quality in the low to medium gray range while maintaining constant current characteristics in the high gray range.

[0038] Furthermore, the system power consumption of the LED display driver chip 100 is related to the break-in voltage VDS. The system power consumption PD of the LED display driver chip 100 is partly derived from the product of the break-in voltage VDS and the output current Iout of the constant current output channel. Therefore, the lower the break-in voltage VDS, the lower the required power supply voltage VCC, the lower the system power consumption PD, and the smaller the heat loss; conversely, the higher the break-in voltage VDS, the higher the required power supply voltage VCC, the larger the system power consumption PD, and the greater the heat loss. Thus, by reducing VDS during high grayscale display, power consumption can be significantly reduced, while during medium-low grayscale display, the power consumption is also relatively low due to the short illumination time of the LED strings.

[0039] In summary, this embodiment dynamically adjusts the transition voltage VDS based on the display brightness. When the display brightness is high, the transition voltage VDS is automatically reduced to ensure the chip's constant current characteristics while reducing heat generation and power consumption. When the display brightness is low, the transition voltage VDS is automatically increased to improve the stability and consistency of the output current, ensuring display quality in the low to medium gray range. Therefore, by using different transition voltages VDS at different display brightness levels, both constant current characteristics under high gray levels and display quality under low to medium gray levels can be balanced, achieving dynamic energy saving. Overall, this reduces the power consumption of the LED display driver chip and improves the flexibility and accuracy of energy efficiency utilization.

[0040] The following combination Figure 3 This embodiment details how each constant current output channel adjusts the transition voltage based on the display brightness.

[0041] Figure 3 A schematic block diagram of a constant current output channel according to an embodiment of the present invention is shown.

[0042] like Figure 3As shown, each constant current output channel 110 in the LED display driver chip 100 has the same structure, including a data processing module 111, a comparison module 112, a bias adjustment module 113, and a constant current driving module 114. The constant current driving module 114 contains a constant current source that provides a constant output current to the LED string; this constant current source is typically implemented using a transistor. The data processing module 111 acquires externally input grayscale data and processes it into a brightness characterization signal representing the display brightness. This brightness characterization signal can be selected from any of the following: the duty cycle of the pulse width modulation signal driving the LED string; the count value of the display subframe formed by scattering grayscale data within a display frame; the calculated value of the duty cycle and the count value; the calculated value of the duty cycle and a constant; or the calculated value of the count value and a constant. The calculations of the duty cycle and the count value mentioned here include summation, product, weighted average, etc., while the calculations of the duty cycle or the count value and a constant can include product and summation, etc. The brightness representation signal reflects the relative brightness level within the current display frame or sub-frame. In other words, grayscale data can be processed into a brightness representation signal, which is directly mapped to the LED's display brightness. Therefore, the magnitude of this brightness representation signal can be used to determine the current grayscale level of the LED display. The comparison module 112 then compares the value of the brightness representation signal with a preset threshold and outputs the comparison result. The comparison result indicates whether the current grayscale value is in the high grayscale range or a non-high grayscale range (medium-low grayscale range), or whether the corresponding display image is a high grayscale image or a non-high grayscale image. For example, when the current grayscale value is greater than a preset first grayscale value, it is in the high grayscale range, and the corresponding display image is a high grayscale image; when the current grayscale value is less than or equal to the preset first grayscale value, it is in the non-high grayscale range, and the corresponding display image is a non-high grayscale image (including medium-grayscale and low grayscale images). Furthermore, a second grayscale value can be preset, which is less than the first grayscale value. When the current grayscale value corresponding to the grayscale data is less than the second grayscale value, it is in the low grayscale range, and the corresponding displayed image is a low grayscale image. When the current grayscale value corresponding to the grayscale data is greater than or equal to the second grayscale value but less than or equal to the first grayscale value, it is in the medium grayscale range, and the corresponding displayed image is a medium grayscale image. The first and second grayscale values ​​can be set according to actual needs. The distinction between high grayscale images and non-high grayscale images depends on the specific grayscale values ​​of the grayscale data.

[0043] The bias adjustment module 113 dynamically adjusts the bias voltage Vbias provided to the constant current drive module 114 based on the comparison result, thereby adjusting the transition voltage VDS at the channel output terminal to vary with display brightness. The bias adjustment module 113 can also provide a bias current or other bias signals to achieve dynamic adjustment of VDS. For example, it could adjust the constant current source in the constant current drive module 114, or adjust the drain-source voltage of the transistor acting as the constant current source, or adjust the current or voltage received by other circuit structures connected to the transistor. This changes the magnitude of the transition voltage VDS between the output terminal and ground terminal of the constant current output channel 110.

[0044] Therefore, in this embodiment, when the value of the brightness representation signal does not exceed (is less than or equal to) a preset threshold, it indicates that the gray value corresponding to the current grayscale data is in a non-high gray range. At this time, the bias voltage Vbias output by the bias adjustment module 113 is adjusted to increase the transition voltage VDS. When the value of the brightness representation signal exceeds or exceeds the preset threshold, it indicates that the gray value corresponding to the current grayscale data is in a high gray range. The bias voltage Vbias output by the bias adjustment module 113 is adjusted to decrease the transition voltage VDS. This achieves dynamic adjustment of the transition voltage VDS, and the display brightness of the corresponding image is higher when the grayscale value corresponding to the grayscale data is in a high gray range than when the grayscale value is in a non-high gray range.

[0045] In this embodiment, the data processing module 111 may further include a data conversion unit, a timer, and a counter. The data conversion unit is used to convert the received grayscale data into a continuous pulse width modulation (PWM) signal. This PWM signal can drive an LED string to achieve grayscale display and can control the current and brightness of the LED string. Typically, the grayscale data corresponding to a display frame, after conversion to form a continuous PWM signal, forms multiple pulse groups, i.e., a PWM signal pulse group appears at intervals, and each pulse group corresponds to a display subframe. In this embodiment, each PWM signal pulse group consists of multiple consecutively occurring and identical PWM signals, i.e., pulse sequences with the same shape and specific intervals. The timer is used to time the high-level duration of a single pulse's PWM signal to obtain the duty cycle of the PWM signal (the ratio of the high-level duration to the switching period). The counter is used to count the number of PWM signal pulse groups within a display frame, which serves as the count value for the display subframe. This pulse group includes multiple consecutive PWM signals. This allows the output of the duty cycle of the pulse width modulation signal or the count value of the display subframe as a brightness characterization signal, reflecting the average brightness level of the current display frame. In other embodiments, the product or sum of the two can also be used as the brightness characterization signal, or it can be the result of an operation between one of the two and a constant, or it can be any other signal that can characterize the average display brightness corresponding to the current grayscale data.

[0046] Taking the duty cycle of the pulse width modulation signal as a brightness characterization signal as an example, and selecting a preset threshold value between 40% and 55%, for example, choosing 40% as the preset threshold, when the specific value of the duty cycle of the pulse width modulation signal is less than 40%, it is determined that the current display brightness is low, in the low-to-medium gray range. The bias voltage Vbias output by the bias adjustment module 113 increases the transition voltage VDS (for example, by increasing it based on the initial setting value). While the transition voltage VDS increases, its current accuracy improves. At this time, the current consistency of the low-to-medium gray range is significantly improved compared to the initial setting value of the transition voltage. Since the duty cycle of the pulse width modulation signal is very small, even if VDS increases slightly, the power consumption in the low-to-medium gray range will not increase significantly. Under these circumstances, both power consumption and display quality can be guaranteed. Conversely, when the specific value of the duty cycle of the pulse width modulation signal is greater than 40%, it is determined that the current display brightness is high, in the high-to-medium gray range. The bias voltage Vbias output by the bias adjustment module 113 decreases the transition voltage VDS, ensuring that the output current Iout is in the constant current range. At this point, the transition voltage VDS decreases, ensuring the constant current characteristics in the high gray range while reducing heat generation.

[0047] Alternatively, two preset thresholds can be set, with the first threshold being less than the second. When the duty cycle of the pulse width modulation (PWM) signal, which represents brightness, is less than the first preset threshold, the grayscale value of the grayscale data is determined to be in the low-to-medium gray range, indicating low display brightness. In this case, the transition voltage VDS is increased to exceed the initial preset value. Although VDS increases, the increased power consumption is negligible due to the small duty cycle of the PWM signal. Conversely, when the duty cycle of the PWM signal exceeds the second preset threshold, the grayscale value of the grayscale data is determined to be in the high gray range, indicating high display brightness. In this case, the transition voltage VDS is decreased to less than the initial preset value. Since the duty cycle of the PWM signal is relatively large in high gray ranges, reducing VDS can significantly reduce power consumption PD, achieving energy saving. When the duty cycle of the PWM signal is between the first and second preset thresholds, the transition voltage VDS is maintained at the initial preset value to maintain a balance between system stability and display quality.

[0048] In another embodiment, taking the count value of the display subframe or the number of pulse groups of the pulse width modulation signal as the brightness characterization signal as an example, and selecting a preset threshold value between 16 and 35, for example, selecting 20 as the preset threshold, the chip internally uses the data processing module 111 to detect and output the number of pulse groups as the count value in real time. When the count value is less than or equal to 20, it is determined that the current display grayscale value is in the low gray range, and the bias adjustment module 113 controls the bias voltage Vbias of the constant current drive module 114 to increase the transition voltage VDS. When the count value is greater than 20, it is determined that the current display grayscale value is in the high gray range, and the bias adjustment module 113 controls the bias voltage Vbias of the constant current drive module 114 to decrease the transition voltage VDS. This can reduce the overall power consumption of the LED display driver chip 100. Of course, two preset thresholds can also be set in this embodiment; the specific comparison process will not be described in detail.

[0049] See also Figure 3In this embodiment, each constant current output channel further includes a memory 115, a threshold adjustment module 116, and a register 117. The memory 115 is used to receive, store, and latch externally input grayscale data, including static random access memory (SRAM), dynamic random access memory (DRAM), or flash memory. The threshold adjustment module 116 is used to set the specific value of the preset threshold TH, for example, by setting a fixed value. The LED display driver chip 100 can also modify the value of the register 117 within the chip via an external interface to modify the specific value of the preset threshold. Thus, when the LED display driver chip 100 receives externally input grayscale data, it is latched by the internal SRAM. After latching, the data processing module 111 performs signal processing, and the comparison module 112 compares the value of the brightness characterization signal with the preset threshold TH in real time. After the comparison is completed, the comparison result Vc is output to the bias adjustment module 113, which adjusts the transition voltage VDS in real time by changing the bias voltage Vbias, and finally provides a constant output current to the LED string through its respective constant current output channel.

[0050] Figure 4 A schematic diagram of a portion of the circuit structure in a constant current drive module according to an embodiment of the present invention is shown.

[0051] Figure 4 A partial circuit structure of a possible constant current drive module 114 is given, such as... Figure 4 As shown, the constant current drive module 114 includes a transistor M1 as a constant current source, an operational amplifier EA, and an output stage transistor M2. Transistor M1 is connected between transistor M2 and ground, and transistor M2 is connected between transistor M1 and the LED string. The control terminal of transistor M2 is connected to the output terminal of operational amplifier EA. The non-inverting input terminal of operational amplifier EA receives a bias voltage Vbias, and its inverting input terminal is connected to the common node Q of transistors M2 and M1, forming a negative feedback structure. Therefore, by adjusting the bias voltage Vbias, the voltage of the common node Q can be adjusted, thereby changing the breakover voltage VDS. This is only one possible embodiment of the invention; other constant current drive modules 114 can be used in other embodiments. The bias current Vbias or bias current can then be applied to other circuit elements to adjust the breakover voltage VDS. Of course, the constant current drive module 114 can also use existing structures. The present invention does not limit the specific structure of the constant current drive module, as long as it can achieve the function of adjusting the breakover voltage through bias voltage or bias current.

[0052] This invention breaks through the current barrier that all LED display driver chips use statically controlled transition voltages. It eliminates the need for an external control system to adjust the transition voltage level, allowing the chip to dynamically adjust the transition voltage internally by receiving grayscale data that characterizes display brightness. This achieves high grayscale dynamic energy saving while maintaining a low grayscale display effect.

[0053] Figure 5 A schematic flowchart of a transition voltage regulation method according to an embodiment of the present invention is shown.

[0054] like Figure 5 As shown, the transition voltage regulation method of this embodiment is applicable to the above-mentioned Figures 1-4 In the LED display device and LED display driver chip 100 mentioned in the embodiment, the transition voltage adjustment method of this embodiment is used to adjust the transition voltage at the output terminal of each constant current output channel in the LED display driver chip, specifically including steps S101-S104.

[0055] In step S101, grayscale data is received and processed into a luminance representation signal that represents the display brightness.

[0056] In step S102, the value of the brightness characterization signal is compared with a preset threshold, and the comparison result is output.

[0057] The brightness characterization signal is selected from any of the following: the duty cycle of the pulse width modulation signal driving the LED string, the count value of the display subframe formed by the grayscale data being scattered within a display frame, the calculated value of the duty cycle and the count value, the calculated value of the duty cycle and a constant, or the calculated value of the count value and a constant.

[0058] In step S103, the bias voltage supplied to the constant current drive module is dynamically adjusted according to the comparison result to regulate the transition voltage.

[0059] This step specifically includes: when the comparison result indicates that the value of the brightness characterization signal is less than or equal to a preset threshold, adjusting the bias voltage to increase the transition voltage; when the comparison result indicates that the value of the brightness characterization signal is greater than the preset threshold, adjusting the bias voltage to decrease the transition voltage.

[0060] Furthermore, a value greater than a preset threshold indicates that the grayscale value of the current grayscale data is in the high grayscale range, while a value less than or equal to the preset threshold indicates that the grayscale value of the current grayscale data is in the non-high grayscale range.

[0061] In step S104, the constant current drive module provides a constant current to the LED string driven by the constant current output channel according to the adjusted transition voltage. This allows for dynamic adjustment of the transition voltage based on the display brightness, balancing display quality and constant current characteristics.

[0062] Since the functions and relationships of each module have already been described in the above embodiments, they will not be repeated here. The transition voltage regulation method can be implemented based on the working principle described in the above embodiments.

[0063] Furthermore, the present invention also provides an electronic device, which includes a control system and an LED display device, wherein the LED display device includes an LED lamp array and an LED display driver chip for driving the LED lamp array. The LED display driver chip mentioned herein can be found in... Figures 1-4 The illustrated embodiment of the LED display device can be found in [reference needed]. Figure 1 In this embodiment, the electronic device can be used to perform... Figure 5 The method for adjusting the transition voltage is shown. See the above text for a detailed description, which will not be repeated here.

[0064] It should be noted that the numerical values ​​in this article are for illustrative purposes only. Other numerical values ​​may be used to implement this solution in other embodiments of the present invention. The specific values ​​should be reasonably set according to the actual situation, and the present invention does not limit them.

[0065] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

[0066] It should also be understood that the terminology and expressions used herein are for descriptive purposes only, and one or more embodiments described herein should not be limited to these terms and expressions. The use of these terms and expressions does not exclude any illustrative and descriptive equivalent features (or parts thereof), and it should be recognized that various modifications that may exist should also be included within the scope of the claims. Other modifications, variations, and substitutions may also exist. Accordingly, the claims should be considered to cover all such equivalents.

Claims

1. An LED display driver chip, comprising multiple constant current output channels, each constant current output channel driving a plurality of LED strings, wherein, Each of the constant current output channels includes: The constant current drive module provides a constant output current to the LED string; The data processing module acquires grayscale data and processes it into a luminance signal that represents the display brightness. The comparison module compares the value of the brightness characterization signal with a preset threshold and outputs the comparison result; and The bias adjustment module dynamically adjusts the bias voltage supplied to the constant current drive module based on the comparison result, thereby adjusting the transition voltage at the channel output terminal. Specifically, when the comparison result indicates that the value of the brightness characterization signal is less than or equal to the preset threshold, the bias adjustment module adjusts the bias voltage to increase the transition voltage; and when the comparison result indicates that the value of the brightness characterization signal is greater than the preset threshold, the bias voltage adjusts the bias voltage to decrease the transition voltage.

2. The LED display driver chip according to claim 1, wherein, The brightness characterization signal is selected from any one of the following signals: the duty cycle of the pulse width modulation signal driving the LED string, the count value of the display subframe formed by the grayscale data being scattered within a display frame, the calculated value of the duty cycle and the count value, the calculated value of the duty cycle and a constant, or the calculated value of the count value and a constant.

3. The LED display driver chip according to claim 1, wherein, If the value of the brightness characterization signal is greater than the preset threshold, it indicates that the gray value of the current grayscale data is in the high gray range. If the value of the brightness characterization signal is less than or equal to the preset threshold, it indicates that the gray value of the current grayscale data is in a non-high gray range. Furthermore, the display brightness of the image corresponding to grayscale data in the high grayscale range is higher than that of the image corresponding to grayscale data in the non-high grayscale range.

4. The LED display driver chip according to claim 1, wherein, The constant current drive module operates in the constant current region after each adjustment of the transition voltage, providing a constant output current to the LED string.

5. The LED display driver chip according to claim 1, wherein, Each of the constant current output channels also includes: The memory receives and stores grayscale data input from external sources; and The threshold adjustment module sets the specific value of the preset threshold. The memory includes static random access memory, dynamic random access memory, or flash memory. The LED display driver chip modifies the value of the internal register via an external interface to change the specific value of the preset threshold.

6. The LED display driver chip according to claim 2, wherein, The data processing module includes: The data conversion unit converts the grayscale data into a pulse width modulation signal; A timer is used to time the duration of the high level of a single pulse in the pulse width modulation signal to obtain the duty cycle of the pulse width modulation signal; A counter counts the number of pulse groups of the pulse width modulation signal within a display frame, and uses this count as the count value of the display subframe. The pulse group includes multiple consecutive pulses.

7. A method for adjusting a transition voltage, used to adjust the transition voltage at the output terminal of each constant current output channel in an LED display driver chip, wherein, The transition voltage regulation method includes: Receive grayscale data and process it into a luminance representation signal that represents the display brightness; The value of the brightness characterization signal is compared with a preset threshold, and the comparison result is output. The bias voltage supplied to the constant current drive module is dynamically adjusted based on the comparison results to regulate the transition voltage; The constant current drive module is controlled to provide a constant current to the LED string driven by the constant current output channel according to the adjusted transition voltage. The step of dynamically adjusting the bias voltage provided to the constant current drive module based on the comparison result to regulate the transition voltage includes: When the comparison result indicates that the value of the brightness characterization signal is less than or equal to the preset threshold, the bias voltage is adjusted to increase the transition voltage. When the comparison result indicates that the value of the brightness characterization signal is greater than the preset threshold, the bias voltage is adjusted to reduce the transition voltage.

8. The transition voltage regulation method according to claim 7, wherein, The brightness characterization signal is selected from any one of the following signals: the duty cycle of the pulse width modulation signal driving the LED string, the count value of the display subframe formed by the grayscale data being scattered within a display frame, the calculated value of the duty cycle and the count value, the calculated value of the duty cycle and a constant, or the calculated value of the count value and a constant.

9. The transition voltage regulation method according to claim 7, wherein, If the value of the brightness characterization signal is greater than the preset threshold, it indicates that the gray value of the current grayscale data is in the high gray range. If the value of the brightness characterization signal is less than or equal to the preset threshold, it indicates that the gray value of the current grayscale data is in a non-high gray range.

10. An LED display device, comprising: LED display driver chip as described in any one of claims 1 to 6; as well as An LED array connected to the output terminal of the LED display driver chip, the LED array comprising multiple LED strings, and the LED display driver chip comprising multiple constant current output channels, each of the constant current output channels driving a plurality of the LED strings. The LED display driver chip automatically adjusts the transition voltage at the output terminal of each constant current output channel based on the real-time received grayscale data, so that the transition voltage changes with the display brightness.

11. An electronic device, comprising: Control system; as well as An LED display device, comprising an LED lamp array and an LED display driver chip as described in any one of claims 1-6 for driving the LED lamp array.

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