Micro-led pixel array power supply driving system and display device

Abstract

The application provides a Micro LED pixel array power supply driving system and a display device. An independent electrode end of each pixel unit in the Micro LED pixel array is electrically connected with a pixel driving output end of a CMOS driving chip through a corresponding connection point in a pixel-level interconnection bonding layer; the CMOS driving chip comprises a plurality of independent power supply lines and a plurality of current source branches, each current source branch comprising a current source unit for providing a driving current for the pixel unit; an input end of the current source unit is connected with at least one independent power supply line, and an output end of the current source unit is commonly connected to the connection point and connected to the independent electrode end of the corresponding pixel unit through the connection point; at least two current source branches are connected in parallel at the same connection point and converge to provide a total driving current for the same pixel unit, and the independent power supply lines connected by the current source branches connected in parallel at the same connection point are different. The application can reduce the current density of a single power supply line.

Description

Technical Field

[0001] This application relates to the field of MicroLED display driving technology, and in particular to a MicroLED pixel array power supply driving system and a MicroLED display device. Background Technology

[0002] MicroLEDs, with their advantages of ultra-high brightness, ultra-fast response, wide modulation bandwidth, high contrast, and long lifespan, are widely used in AR / VR near-eye displays, optical interconnects, digital automotive lighting, and smart projection. Mainstream solutions employ heterogeneous integration of MicroLED pixel arrays and silicon-based CMOS driver chips, achieving independent driving through pixel-level interconnects. Its core structure consists of three parts: a top MicroLED pixel array (pixel size 2–100 μm), a middle pixel-level interconnect bonding layer, and a bottom Si-based CMOS driver chip.

[0003] like Figure 3 As shown, in traditional array driving architectures, the CMOS backplane provides an independent driving current for each MicroLED pixel. This driving current flows in or out through contact points connected to the MicroLED pixel. Typical architectures include common cathode and common anode.

[0004] For common cathode structures, such as Figure 1 As shown, for a single pixel unit, its CMOS drive current I drv The power supply VDD is connected to the anode of the MicroLED pixel unit through the connection point, and the cathodes of the MicroLED pixel array are all connected to a common ground VSS. When extended to an m×n MicroLED pixel array, each pixel unit in each row has n MicroLED pixel units that are driven by the power supply line VDD of that row. However, each pixel unit is connected in series with only one current source branch. Taking the first row as an example, each pixel point D in that row... 11 D 12 To D 1n Drive current I drv All pixels in the row are powered by VDD1. If all pixels in the row are turned on, the current flowing through VDD1 is n×I. drv For common anode structures, such as Figure 2 As shown, for a single pixel unit, the anodes of its MicroLED pixel array are all connected to a common power supply VDD, and the CMOS drive current I... drv It connects to the cathode of the MicroLED pixel unit from the connection point and flows into the ground VSS.

[0005] In some improved technical solutions, such as those disclosed in patents US20220165208A1 and CN116569655A, in order to achieve more refined control of the driving current of each pixel, the driving current of a single pixel is set as multiple current sources connected in parallel. The on and off of each parallel current source is controlled by a switch, thereby realizing the adjustment of the driving current of each pixel and thus achieving grayscale control.

[0006] However, regardless of the traditional driving architecture or some improved technical solutions mentioned above, each row / column of pixels is powered by a single dedicated power supply line. This means that when a large number of pixels in a row / column are lit simultaneously, a single power supply line must bear the total current of the entire row / column, leading to problems such as excessive current density, increased electromigration risk, Joule heat concentration, and uneven IR drop distribution. Furthermore, improvements such as increasing linewidth or thickening the metal layer are limited by the tiny pixel pitch (2~100μm), offering extremely limited room for improvement.

[0007] Therefore, there is an urgent need for a MicroLED pixel array power supply drive system that can reduce current density, suppress IR voltage drop, and improve power supply reliability while maintaining single-point pixel control. Summary of the Invention

[0008] The purpose of this invention is to provide a MicroLED pixel array power supply and driving system and a MicroLED display device to solve at least one of the above-mentioned technical problems.

[0009] In a first aspect, this application provides a MicroLED pixel array power supply and driving system, comprising: a MicroLED pixel array, a CMOS driver chip, and a pixel-level interconnect bonding layer; The MicroLED pixel array achieves heterogeneous integrated electrical connection with the CMOS driver chip through a pixel-level interconnect bonding layer; The MicroLED pixel array comprises m rows and n columns of pixel units, each pixel unit having an independent terminal and a common terminal; Each pixel unit's independent electrode is electrically connected to the pixel drive output of the CMOS driver chip through a corresponding connection point in the pixel-level interconnect bonding layer. The CMOS driver chip includes multiple independent power supply lines and multiple current source branches, each current source branch including a current source unit for providing driving current to the pixel unit; Each current source branch has its input terminal connected to at least one independent power supply line, and its output terminals are all connected to the connection point, which in turn connects to the independent electrode of the corresponding pixel unit. At least two current source branches are connected in parallel at the same connection point to provide the total driving current for the same pixel unit. The independent power supply lines connected to the current source branches that are connected in parallel at the same connection point are different.

[0010] Optionally, the drive current of each current source unit is set in a current load balancing manner for each independent power supply line.

[0011] Optionally, the number of independent power supply lines is k, where k ≥ m or k ≥ n; The input terminal of each current source branch is connected in parallel with multiple independent power supply lines through a power switch. The output terminals of multiple current source branches are connected to the independent terminals of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. Each pixel unit's CMOS driving area includes a selection switch matrix, which contains the power switch. The selection switch matrix is ​​used to control the on / off state of each power switch, thereby controlling the corresponding independent power supply line to supply power to the corresponding pixel unit.

[0012] Optionally, k=2m, and the selection switch matrix is ​​used to select the independent power supply line of the odd-numbered rows as m to supply power to the pixel units of the odd-numbered rows, and to select the independent power supply line of the even-numbered rows as m to supply power to the pixel units of the even-numbered rows.

[0013] Optionally, k=2n, the selection switch matrix is ​​used to select the independent power supply line of the odd column to power the n odd column pixel units, and select the independent power supply line of the even column to power the n even column pixel units.

[0014] Optionally, k=m, each independent power supply line runs in the row direction, the input terminal of each current source branch is connected in parallel with each independent power supply line through a power switch, and the output terminals of each m current source branch are connected to the independent terminal of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. The total number of current sources is m×m×n.

[0015] Optionally, k=n, each independent power supply line is routed in the column direction, each independent power supply line is connected in parallel to the input terminal of each current source branch through a corresponding power switch, and the output terminals of every n current source branches are connected to the independent terminal of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. The total number of current sources is n×m×n.

[0016] Optionally, the CMOS driver chip further includes a configuration controller, the input of which receives at least one of the following information: the illumination pattern distribution information of the MicroLED pixel array, and the temperature sensor distribution information on the MicroLED pixel array; The output of the configuration controller is connected to the control terminal of the selection switch matrix, and is used to dynamically adjust the combination of the effective power supply lines connected to each pixel unit. The effective power supply lines are independent power supply lines electrically connected to the corresponding pixel units.

[0017] Optionally, the MicroLED pixel array has a common cathode structure, with the common terminal of all pixel units connected to a common ground VSS; the independent terminal of each pixel unit is the anode, and the independent power supply line is an independent VDD power supply line.

[0018] Optionally, the MicroLED pixel array has a common anode structure, with the common terminal of all pixel units connected to a common power supply VDD; the independent terminal of each pixel unit is a cathode, and the independent power supply line is a VSS ground line.

[0019] Optionally, the current values ​​provided by the plurality of current source units are binary weighted or allocated according to a preset ratio.

[0020] Optionally, the current amplitudes output by the plurality of current source units are equal.

[0021] Optionally, the CMOS driver chip is a silicon-based CMOS driver chip.

[0022] Optionally, the size of the pixel unit is 2μm. 100μm, pixel pitch is 2μm 100μm.

[0023] In a second aspect, this application provides a MicroLED display device, which includes the MicroLED pixel array power supply and driving system described in any embodiment of this application.

[0024] The MicroLED pixel array power supply driving system and MicroLED display device in this application split the total driving current of each pixel unit into multiple parallel branches, which are provided by multiple different independent power supply lines, thereby reducing the current density of a single power supply line and reducing the risk of electromigration. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0026] Figure 1 This is a schematic diagram of the power supply and driving circuit for a single pixel array with a conventional common cathode structure in one embodiment; Figure 2This is a schematic diagram of the power supply drive circuit for a single pixel array with a conventional common anode structure in one embodiment; Figure 3 This is a schematic diagram of the power supply and driving circuit for each pixel unit of an m×n MicroLED pixel array in a conventional common cathode structure in one embodiment. Figure 4 This is a schematic diagram of the power supply driving circuit for a single pixel array of the common cathode structure of this application in one embodiment; Figure 5 This is a schematic diagram of the power supply driving circuit for a single pixel array of the common anode structure of this application in one embodiment; Figure 6 This is a schematic diagram of the current source branches and power lines, and the circuit connections between array units in a 2x3 MicroLED pixel array in one embodiment. Figure 7 This is a schematic diagram of the current source branches and power lines, and the circuit connections between array units in a 2-row, 3-column MicroLED pixel array in another embodiment. Figure 8 This is a schematic diagram of the current source branches and power lines, and the circuit connections between array units in an m-row n-column MicroLED pixel array in another embodiment. Figure 9 This is a schematic diagram of the circuit connection between a single array unit and the current source branch and power line in an m-row n-column MicroLED pixel array in another embodiment. Figure 10 This is a schematic diagram of the power supply method for the array units of an m-row n-column MicroLED pixel array in one embodiment; Figure 11 This is a schematic diagram of the current source branch allocation of the array cells of an m-row n-column MicroLED pixel array in one embodiment. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] All terms used in this application (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0029] For example, the terms "first" and "second" used in this application are only used to distinguish similar objects and differentiate the first object from another object, rather than to describe a specific order or sequence, nor should they be interpreted as indicating or implying relative importance.

[0030] This application proposes a power supply and driving system for a MicroLED pixel array, comprising a MicroLED pixel array, a CMOS driver chip, and a pixel-level interconnect bonding layer. The MicroLED pixel array is heterogeneously integrated with the CMOS driver chip via the pixel-level interconnect bonding layer. The MicroLED pixel array comprises m rows and n columns of pixel units, each pixel unit having an independent terminal and a common terminal. The independent terminal of each pixel unit is electrically connected to the pixel driving output terminal of the CMOS driver chip via a corresponding connection point in the pixel-level interconnect bonding layer. The CMOS driver chip includes multiple independent power supply lines and multiple current source branches, each current source branch including a current source unit for providing driving current to the pixel units.

[0031] The MicroLED pixel array is a light-emitting unit array formed by arranging multiple micro-light-emitting diodes (MicroLEDs) according to a row and column rule. Each MicroLED is an independent pixel unit, and its brightness and grayscale level can be independently controlled. For example, it can be arranged in an m x n matrix form, where m and n are any suitable integers ≥ 1. This m x n pixel unit can constitute a whole MicroLED pixel array, or it can be a partition of the entire MicroLED pixel array.

[0032] A pixel unit is the smallest independently controllable light-emitting unit in a MicroLED pixel array. Each pixel unit includes a cathode and an anode, one end of which is an independent electrode, and the other end is a common electrode. The independent electrode is directly controlled by the CMOS driver chip, through which the driving current flows into or out of the pixel. The common electrode is the electrode that is connected to all other pixel units in the same array. When there is a common cathode, it is grounded (VSS), and when there is a common anode, it is connected to the common power supply (VDD).

[0033] When the MicroLED pixel array has a common cathode structure, the common terminal (cathode) of all pixel units is connected to a common ground VSS; the independent terminal of each pixel unit is the anode, and the independent power supply lines are independent VDD power supply lines. Figure 4 As shown, taking a single pixel unit as an example, there are m independent power supply lines (VDD1, VDD2 to VDD...). m Each of the m current sources is connected to a current source, and the driving currents provided by these m current sources are denoted as I1, I2, ..., I... mAfter m current sources are connected and joined together at the connection point, they are connected to the anode of the corresponding pixel unit through a common pixel switch S1. The total driving current I of the pixel unit is... drv That is, the sum of the driving currents provided by each current source, i.e., I drv =I1+I2+…+I m .

[0034] Alternatively, when the MicroLED pixel array has a common anode structure, the common electrode (anode) of all pixel units is connected to a common power supply VDD; the independent electrode of each pixel unit is a cathode, and the independent power supply line is a ground line VSS. Figure 5 As shown, taking a single pixel unit as an example, there are m independent power supply lines (VSS1, VSS2 to VSS). m Each of the elements is connected to a current source, and after being combined and connected at a connection point, they are connected to the cathode of the pixel unit through a common pixel switch S1. The total driving current I of the pixel unit is... drv Similarly, the sum of the driving currents provided by each of the m current sources is denoted as I1, I2…I… m , then I drv =I1+I2+…+I m .

[0035] In a MicroLED pixel array, the size and spacing between pixel units can be set according to the actual application scenario, for example, the size of the pixel unit can be set to 2μm. 100μm, pixel pitch is 2μm 100μm. Pixel pitch represents the distance between the center points of two adjacent MicroLED pixel units, equal to the sum of the pixel size and the inter-pixel spacing. The pixel unit size represents the physical dimension of a single MicroLED pixel unit in the horizontal direction, typically referring to the side length (for square pixels) or diameter (for circular pixels) of the light-emitting area. Table 1 below shows suitable size ranges, typical size values, suitable pitch ranges, and typical pitch values ​​for some typical application scenarios.

[0036] Table 1

[0037] A CMOS driver chip is an integrated circuit chip manufactured using complementary metal-oxide-semiconductor (CMOS) technology. It integrates circuit modules required for pixel driving, such as current sources, switches, control logic, and power distribution networks. This chip is vertically integrated with the MicroLED pixel array through a pixel-level interconnect bonding layer. The CMOS driver chip can receive display data and control signals, generate precise drive current for each pixel unit, and control the brightness and grayscale level of each pixel. Optionally, this CMOS driver chip is a silicon-based CMOS driver chip.

[0038] The pixel-level interconnect bonding layer is a metal interconnect structure layer located between the MicroLED pixel array and the CMOS driver chip, used to achieve electrical connection between the two. This layer contains multiple electrically isolated connection points (e.g., metal bumps, pads, or direct metal bonding structures), each connection point connecting a single pixel unit's independent electrical terminal to the corresponding pixel drive output terminal in the CMOS driver chip one-to-one. The pixel-level interconnect bonding layer can employ metal thermocompression bonding (Au). Au, Cu This can be achieved through processes such as Cu), solder micro-bump bonding (SnAg, In), and hybrid bonding (Cu / SiO2 or Cu / SiCN).

[0039] Connection points are metal interconnect structures in the pixel-level interconnect bonding layer, used to achieve a one-to-one electrical connection between the independent electrical terminals of a single pixel unit and the corresponding pixel driver output terminal in the CMOS driver chip. Each pixel unit corresponds to one and only one connection point, and the connection points corresponding to different pixel units are electrically isolated from each other. This connection point also serves as the common confluence point for the output terminals of multiple current source branches. Connection points typically take the form of metal microbumps (e.g., bumps with a diameter of 1μm to 25μm), metal bonding pads (e.g., pads with dimensions of 2μm×2μm to 30μm×30μm), or direct metal... Forms such as metal bonding interfaces.

[0040] Independent power supply lines refer to metal traces in a CMOS driver chip used to carry power and provide input current to current source branches. Each independent power supply line is directly connected to the input terminal of a corresponding current source branch. Physically, each power supply line is a separate metal trace, and they are not directly short-circuited within the chip. Different power supply lines can carry different or the same current / voltage, and different power supply lines can be connected to different external power pads. The number of independent power supply lines can be any suitable number, such as the same as or greater than the number of rows or columns of the pixel array.

[0041] For example, in a common cathode structure, there are three independent power supply lines: VDD_a, VDD_b, and VDD_c; while in a common cathode structure, there are three independent power supply lines: VSS_a, VSS_b, and VSS_c. In the prior art, all current source branches typically share the same VDD or VSS bus. In this application, each current source branch connected to the same pixel unit has a different independent power supply line.

[0042] A current source branch generates and controls a portion of the drive current flowing to the pixel unit. It includes a current source unit and may further include a switching unit (such as a power switch and / or a pixel switch) connected to the current source unit. That is, the current source branch can be a circuit branch formed by series / parallel connection of current source units and switching units. A current source unit is a circuit module that generates a constant current of a set magnitude. Its output current value does not change with the load voltage. The drive current provided by each current source unit can be the same or different (e.g., partially the same). The switching unit controls the on / off state of the current source branch. Each pixel unit corresponds to a set of parallel current source branches, and the output terminals of all branches are connected to the connection point of that pixel unit.

[0043] Among them, multiple current source units electrically connected to the same pixel unit can share a single switching unit (e.g., Figures 4 to 9 Switches S1 and S in 11 ~S mn Alternatively, each current source branch can be equipped with its own independent switching unit (e.g., Figure 8 and Figure 9 Switch in When a single switching unit is shared, that switching unit serves as the master switch for the corresponding pixel unit, used to simultaneously control the on / off state of multiple connected current sources. When each current source branch is configured with its own switching unit, that individually configured switching unit can only control the on / off state of its corresponding current source branch.

[0044] In this embodiment, the input terminal of each current source branch is connected to at least one independent power supply line, and the output terminals are all connected to the connection point, which is then connected to the independent terminal of the corresponding pixel unit. At least two current source branches are connected in parallel at the same connection point to provide the same total driving current for the same pixel unit. The independent power supply lines connected to the current source branches that are connected in parallel at the same connection point are different.

[0045] Specifically, the MicroLED pixel array is flip-chip bonded to the CMOS driver chip via a pixel-level interconnect bonding layer, which is located between the MicroLED pixel array and the CMOS driver chip. For each pixel unit, the corresponding connection point is located in the pixel-level interconnect bonding layer. One end of the connection point is connected to the independent terminal of the pixel unit, and the other end is connected to the drive output terminal of the pixel in the CMOS driver chip (i.e., the common confluence point of multiple current source branches). Multiple independent power supply lines can be routed in parallel within the chip, either in a row-wise or column-wise direction. Each independent power supply line is connected to the input terminal of the current source unit in the corresponding current source branch. The output terminal of the current source unit is connected in series with one end of a switching unit. The other end of the switching unit (i.e., the output terminal of the current source branch) is connected to the common node (the connection point of the pixel). The control terminal of the switching unit is connected to the output terminal of the pixel control logic, which generates a switching control signal based on the display data.

[0046] For the common terminal, in the common cathode structure, the common electrode (cathode) of all pixel units is connected to the common VSS pad of the chip; in the common anode structure, the common electrode (anode) of all pixel units is connected to the common VDD pad of the chip.

[0047] For each pixel unit, among its multiple current source branches, the input terminal of each current source branch is connected to one or more independent power supply lines. The output terminals of all current source branches corresponding to the same pixel unit are connected to the connection point corresponding to that pixel unit, and then connected to the independent terminal of that pixel unit through the connection point. Multiple current source branches are connected in parallel at this connection point to provide a total driving current for that pixel unit.

[0048] When each current source branch has only one independent power supply line, it means that only that one independent power supply line supplies power to the current source unit in that branch, and the power switch in the branch can be retained or omitted. When there are multiple independent power supply lines, each independent power supply line is connected to the same current source unit through a power switch. The power supply line connected to the corresponding current source unit is the effective power supply line for that current source unit (current source branch). By selecting the power switch, the load on each effective power supply line can be adjusted.

[0049] Optionally, the number of current source branches connected in parallel to each pixel unit can be any suitable number from 2 to k. The number of current source branches connected in parallel to each pixel unit can be the same or different, and the number of independent power supply lines connected to each current source unit can also be the same or different. k represents the number of independent power supply lines. For example, if k=m, the number of current source branches connected in parallel to each pixel unit is also m, and the number of power supply lines connected to each current source branch is also m.

[0050] The MicroLED pixel array power supply and driving system in this application divides the total driving current of each pixel unit into multiple parallel branches, each supplied by a different independent power supply line, which greatly reduces the current density of a single power supply line. For example, if the number of current source branches connected in parallel to a single pixel unit is y, and the current in each branch is the same, the current carried by each power supply line is reduced to 1 / y of the total driving current, thereby significantly reducing the risk of electromigration.

[0051] Furthermore, the IR voltage drop is proportional to the current flowing through the power supply line. Since the current in each independent power supply line is reduced to 1 / y of that in the conventional solution, the voltage drop along the line is also reduced by about 1 / y, which can further improve brightness uniformity. In addition, by distributing the current to multiple power supply lines, the heat source is more evenly distributed in the chip space, reducing local peak temperature.

[0052] As MicroLED technology advances towards smaller size, higher brightness, and higher reliability, the requirements for current density per pixel are increasing across various applications, including AR / VR, smart automotive lighting, HUDs, and data center optical interconnects. For example, in AR / VR applications, a typical driving current of 2µA is required when the pixel size is 4µm x 4µm. In smart automotive lighting, the typical pixel size is 40µm x 40µm, and the typical driving current is 2mA, representing an order of magnitude increase in current density per unit area.

[0053] The traditional approach is to use VDD or VSS to provide current and "fixed" it as a global signal to supply current to the pixel array. The solution to the problem of excessive current density is to use wide or thick single power lines. However, in MicroLED driver chips, the width of a single power line is limited by the size of the pixel unit, and increasing the thickness of a single power line is limited by the fabrication process itself.

[0054] Based on the operating characteristics of MicroLED arrays, the total driving current of each row of pixel arrays dynamically changes according to the needs of the displayed content. For example, in the first row, most of the pixel arrays are lit, resulting in a larger current flowing through the power supply lines of that row; in the second row, most of the pixel arrays may be off, resulting in a smaller current flowing through the power supply lines of that row. This can lead to an excessively high current density in the power supply lines of the first row, while the current density in the power supply lines of the second row is too low, failing to utilize the full driving potential. Conversely, the opposite may also occur, with the current density in the power supply lines of the first row being too low and the current density in the power supply lines of the second row being too high.

[0055] Based on this, this application creatively proposes the idea of ​​dynamically configurable power supply lines. From a global perspective, by making the power supply lines of the pixel array configurable, the utilization efficiency of the power supply lines of the entire MicroLED array is improved. Under the condition that any MicroLED array pixel is turned on or off, it is possible to ensure that each power supply line carries a basically the same current, thereby achieving a balanced distribution of the current density of the power supply lines and reducing the problem of excessive current density in any one power supply line.

[0056] This significantly improves the overall system reliability and chip energy efficiency, including: a significant reduction in the risk of electromigration in the power supply lines; a reduction in the parasitic IR voltage drop of the power supply lines, resulting in improved uniformity of MicroLED pixel brightness; improved heat dissipation performance of the chip, with heat sources dispersed to enhance reliability; and redundant power supply design in parallel power lines to achieve redundant power supply even in the event of a single power line open circuit, thus improving system reliability.

[0057] In one embodiment, the drive current of each current source unit is set according to the current load balancing method of each independent power supply line.

[0058] In this embodiment, by reasonably allocating the driving current values ​​of each current source branch within each pixel unit, the total current flowing through each independent power supply line (i.e., the sum of the currents of all pixel units corresponding to that power supply line) can be made as equal as possible, thereby preventing a power supply line from aging prematurely or generating excessive IR voltage drop due to overload. Through load balancing settings, the total power supply current carried by the independent power supply line VDD1 is denoted as I_VDD. i By setting the drive current of each current source through load balancing, the k independent power supply lines (VDD1, VDD2...VDD...) can be made more efficient. k The total supply current (I_VDD1, I_VDD2...I_VDD) k They are basically the same.

[0059] Specifically, based on the load balancing objective, different current values ​​are allocated to each current source unit within each pixel unit, so that the total load current of each independent power supply line is balanced under a given display content (lit pattern).

[0060] For example, the driving current of each current source can be set to be the same, and the number of current source branches connected to each independent power supply line can also be the same, so that the total power supply current borne by each independent power supply line is also the same. Furthermore, different driving current magnitudes of current sources can be allocated, but the total driving current of each pixel unit and the total power supply current of each independent power supply line can be made the same.

[0061] For example, it can be set that the maximum current provided by a single power supply line is the same. Figure 6 and Figure 7 As shown, in a 2×3 common-cathode MicroLED pixel array, there are two independent power supply lines, denoted as VDD1 and VDD2, and six pixel units, denoted as D. 11 To D 23 Each power supply line is connected to a pixel unit through an independent current source branch, and each pixel unit is connected in parallel to two current source branches that are connected to different independent power supply lines. Figure 6 In the diagram, each current source provides a driving current value of I1, then the total driving current I of each pixel unit is... drv =I1+I1, in all switches (S 11 To S 23 When all three power lines are conducting, the total supply current borne by each independent power supply line is 6 × I1; while Figure 7 In the pixel array, the driving current of one part of the current source unit is I1, and the driving current of the other part is I2; in the pixel array, the driving currents provided by different current source units of each pixel unit are interleaved as I1 and I2, and are provided by different independent power supply lines, so that the total driving current of each pixel unit is I drv =I1+I1, the total supply current borne by each independent power supply line is 3×I1+3×I2. Thus, load balancing is achieved.

[0062] exist Figure 6 and Figure 7 In the middle, if all pixels in the first row are off and all pixels in the second row are on, then Figure 6 The current flowing through VDD1 and VDD2 is 3×I1. Figure 7 The current flowing through VDD1 is 3×I1, and the current flowing through VDD2 is 3×I2.

[0063] exist Figure 6 and Figure 7 In the middle, if all pixels in the first row are on and all pixels in the second row are off, then Figure 6 The current flowing through VDD1 and VDD2 is 3×I1. Figure 7 The current flowing through VDD1 is 3×I2, and the current flowing through VDD2 is 3×I1.

[0064] While ensuring the load balancing design, as long as not all pixels are turned on at the same time, the power supply line distribution method of this invention ensures that the current required by a single power supply line is less than that of the traditional power supply line method.

[0065] In one embodiment, the number of independent power supply lines is k, where k≥m or k≥n; the input terminal of each current source branch is connected in parallel with multiple independent power supply lines via a power switch, and the output terminals of multiple current source branches are connected to the independent terminals of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit; each pixel unit's CMOS driving area includes a selection switch matrix, which contains the power switch, and the selection switch matrix is ​​used to control the on / off state of each power switch to control the corresponding independent power supply line to supply power to the corresponding pixel unit.

[0066] In this embodiment, taking the direction of independent power supply lines along the row as an example, the number of independent power supply lines is k≥m. When the number of independent power supply lines connected in parallel in each pixel unit is q (e.g., q=2,3……k), the selection degree of freedom that the selection switch matrix can control is C(k, q) combinations. Taking the direction of independent power supply lines along the column as an example, the number of independent power supply lines is k≥n. When the number of independent power supply lines connected in parallel in each pixel unit is n, the selection degree of freedom that the selection switch matrix can control is C(k, n) combinations.

[0067] For example, when m=4 and k=5, the selection switch matrix for each pixel is a 5-to-4 cross switch. For each pixel unit, 4 out of 5 independent power supply lines can be selected as the effective power supply lines for the corresponding pixel unit. The effective power supply lines are independent power supply lines electrically connected to the corresponding pixel unit. For example, for pixel unit D... 11 VDD1~VDD4 are selected as its effective power supply lines for pixel unit D. 44 Select VDD2~VDD5 as its effective power supply lines.

[0068] Taking a single pixel unit with q (q≤k) effective power supply lines in a current source branch as an example, when it is necessary to activate one of the current source branches of a pixel unit, the power switch of one of the q independent power supply lines in the current source branch can be closed by selecting a switch matrix, while the switches of the remaining independent power supply lines remain open. This allows one independent power supply line to be selected to independently provide the driving current of the corresponding current source branch. Alternatively, the power switches of multiple independent power supply lines can be closed, so that the multiple independent power supply lines can jointly provide the driving current of the corresponding current source branch.

[0069] By selecting a switch matrix to control the opening and closing of each switch unit, the distribution of drive current from the independent power supply line to the pixel unit can be controlled, thereby achieving load balancing.

[0070] The number of independent power supply lines connected to each current source branch can be the same or different, and the number of independent power supply lines can also be the same or different. For example, each current source branch can be connected in parallel with the same number of independent power supply lines (such as 1, 2, m, n, k, or any suitable number), and each pixel unit can be connected in parallel with the same number of current source branches (such as 2, 3, m, n, or any suitable number).

[0071] For example, each of the k rows of power lines can supply power to m independent drive current sources for each of its corresponding columns. Since k ≥ m, the m independent power lines supplying power to each pixel unit can be a subset of the total k power lines. Depending on the requirements, m of the k power lines can be selected as the power lines for the pixel unit, thus providing greater flexibility in selecting the power lines for any MicroLED pixel unit.

[0072] In one embodiment, k=m, each independent power supply line runs in the row direction, the input terminal of each current source branch is connected in parallel with each independent power supply line through a power switch, and the output terminals of each m current source branch are connected to the independent terminal of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. The total number of current sources is m×m×n.

[0073] In one embodiment, k=n, each independent power supply line runs in the column direction, and each independent power supply line is connected in parallel to the input terminal of each current source branch through a corresponding power switch. The output terminals of every n current source branches are connected to the independent terminal of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. The total number of current sources is n×m×n.

[0074] In this embodiment, the number of independent power supply lines can be the same as the number of rows or columns of the pixel array. Taking the number of independent power supply lines Z=m as an example, each independent power supply line runs horizontally in the chip (along the row direction) and provides current to the current source branches corresponding to all m×n pixel units in the MicroLED pixel array. Specifically, for the i-th independent power supply line (i = 1, 2, …, m), the number of its parallel current source branches is m×n. Each pixel unit is connected to one current source branch on this independent power supply line, and the total number of current source branches is m×m×n. Similarly, when Z=n, each independent power supply line runs vertically in the chip (along the column direction) and provides current to the current source branches corresponding to all m×n pixel units in the MicroLED pixel array. Specifically, for the i-th independent power supply line (i = 1, 2, …, n), the number of its parallel current source branches is m×n. Each pixel unit is connected to a current source branch on the independent power supply line, and the total number of current source branches is n×m×n.

[0075] For example, such as Figure 6 and Figure 7 As shown, a 2×3 (m=2, n=3) MicroLED pixel array connected in a common cathode configuration is used as a specific example. Each pixel unit has two current source branches (m=2). These two independent power supply lines are denoted as VDD1 and VDD2, respectively. For each independent power supply line, six current source branches are connected in parallel. The input of each current source branch is connected to the independent power supply line, and the output is connected to the corresponding pixel unit. The number of current source branches (the number of current source units) is m×m×n=12.

[0076] For each power supply line, the magnitude of the driving current provided can be the same or different, for example... Figure 6 In the diagram, the driving current provided by the current source branches connected to VDD1 and VDD2 is I1, and the total driving current for each pixel unit is I. drv =2I1; and Figure 7 In the diagram, the driving current values ​​provided by the current source branches connected to VDD1 and VDD2 are alternately set to I1 and I2, respectively, so that the total driving current I of each pixel unit is... drv =I1 + I2. The total maximum drive current provided by each independent power supply line VDD1 and VDD2 is 3×I1 + 3×I2. Among them, I1 and I2 may not be equal, or they may be a binary weighted relationship, or they may meet other ratios set by the system.

[0077] Extending to an m×n MicroLED pixel array, taking k=m and with independent power supply lines routed in the row direction as an example, as follows: Figure 11As shown, each pixel unit has m current source branches connected in parallel ( Among them, the current source branch The subscripts i and j in the text indicate the pixel unit D connected to the current source branch. ij The superscript q indicates that the pixel unit D ij The q-th current source branch connected to it. Furthermore, as... Figure 10 As shown, the driving current values ​​provided by the current source units in the m parallel current source branches of each pixel unit are I1, I2...I... m When all current source branches are activated, the total driving current value of the corresponding pixel unit remains unchanged at I. drv =I1+I2+……+I m .

[0078] Figure 11 The diagram only shows the current source branch of the pixel unit in the q-th row (q=1,2……m). The input terminals (i=1,2……m; j=1,2,……n) are connected only to the corresponding q-th independent power supply line VDD. q However, in reality, it can connect to more independent power lines, not just one corresponding row's independent power line. For example... Figure 8 and Figure 9 As shown, each current source branch can have multiple independent power supply lines connected in parallel to its input terminal. Figure 9 In the diagram, pixel unit D is denoted as D. ij The driving currents provided by the p parallel current source branches are respectively When all these current source branches are conducting, the total driving current is the sum of the p current values.

[0079] In one embodiment, k=2m, and the selection switch matrix is ​​used to select the independent power supply line of the odd-numbered row to power the pixel unit of the odd-numbered row, and select the independent power supply line of the even-numbered row to power the pixel unit of the even-numbered row.

[0080] In one embodiment, k=2n, the selection switch matrix is ​​used to select the independent power supply lines of the odd-numbered columns to power the pixel units of the odd-numbered columns, and select the independent power supply lines of the even-numbered columns to power the pixel units of the even-numbered columns.

[0081] In this embodiment, the number of selectable independent power supply lines is twice the number of rows or columns of the pixel array. Taking k=2m, m=4, and k=8 as examples, for odd-numbered rows of pixels (m=1,3), four lines are selected from VDD1, VDD3, VDD5, and VDD7 as effective power supply lines; for even-numbered rows of pixels (m=2,4), four lines are selected from VDD2, VDD4, VDD6, and VDD8 as effective power supply lines. In this way, the power supply lines of odd and even rows of pixels are physically staggered, further dispersing the current load and reducing the coupling capacitance between power supply lines.

[0082] Furthermore, this application allows for dynamic reconfiguration of the power supply line selection for each pixel during the display process. For example, a configuration controller can be set up to adjust the line selection strategy in real time based on the following information: the current frame's illumination pattern (which pixels are lit and their brightness levels), real-time voltage monitoring feedback on each power supply line, and the chip temperature distribution map. The dynamic reconfiguration process includes: in the detection phase, monitoring the voltage at different nodes of each power supply line and calculating the IR voltage drop distribution; in the optimization phase, solving for the optimal line selection combination (minimizing the full-screen brightness difference) based on the voltage drop distribution; in the configuration phase, during vertical blanking, writing the new line selection configuration into the selection switch matrix register of each pixel; and in the application phase, starting from the next frame, using the new line selection configuration for display.

[0083] Multiple switches on the power supply lines for each pixel unit can be arbitrarily turned off as needed, for example, selecting one or more of the VDD power lines from k rows to supply power. For example, using... Figure 9 The power supply strategy can also pre-map the power supply strategy of each pixel unit according to the lighting distribution of the entire array, thereby achieving optimal power supply line distribution and global power supply current sharing.

[0084] Figure 9 The configurable pixel array power supply line distribution allows for the optimal power supply line distribution to be configured based on preconditions such as the pixel illumination configuration information before the screen array is lit, or temperature information obtained from the on-chip temperature sensor of the screen array. For example, for each pixel, the m power supply lines with the smallest voltage drop are selected as its effective power supply lines, so that the power supply voltage obtained by all pixels is as close as possible to the target value.

[0085] This embodiment achieves power redundancy and improves system reliability by setting up k independent power supply lines. Thus, even if a global power supply line experiences an open circuit failure, each pixel can still switch to another normal power supply line via a selection switch matrix, ensuring uninterrupted display functionality.

[0086] In one embodiment, the CMOS driver chip further includes a configuration controller. The input of the configuration controller receives at least one of the following information: the illumination pattern distribution information of the MicroLED pixel array and the temperature sensor distribution information on the MicroLED pixel array. The output of the configuration controller is connected to the control terminal of the selection switch matrix and is used to dynamically adjust the combination of the effective power supply lines connected to each pixel unit. The effective power supply lines are independent power supply lines electrically connected to the corresponding pixel units.

[0087] In this embodiment, the configuration controller is a digital control module integrated into the CMOS driver chip. It is responsible for receiving information from external or internal sensors, calculating the optimal power supply line selection scheme, and writing configuration data into the selection switch matrix register of each pixel. The output of the configuration controller is connected to the control terminal of the selection switch matrix in each pixel unit. Based on the received information, the configuration controller dynamically calculates the optimal effective power supply line combination for each pixel unit and writes the corresponding configuration data into the selection switch matrix of each pixel, thereby achieving dynamic adjustment of the power supply line combination selected by each pixel unit.

[0088] Specifically, by acquiring the grayscale data of the current frame and the temperature of each node of each power supply line, the voltage drop distribution of each power supply line is calculated based on the temperature and grayscale data. Then, the optimal combination is selected from the corresponding effective power supply lines based on the voltage drop distribution, so that the selected optimal combination can satisfy the highest actual power supply voltage of the pixel as much as possible, and the selected combination of each pixel is consistent.

[0089] In one embodiment, a MicroLED display device is provided, which includes the MicroLED pixel array power supply and driving system described in any embodiment of this application.

[0090] The MicroLED display device can be any suitable display device, such as an in-vehicle display device (e.g., an in-vehicle central control display screen) or a projection display device.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0092] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are meant to be within the scope of this application and form different embodiments. For example, all the embodiments above can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A power supply and driving system for a MicroLED pixel array, characterized in that, include: MicroLED pixel array, CMOS driver chip, pixel-level interconnect bonding layer; The MicroLED pixel array achieves heterogeneous integrated electrical connection with the CMOS driver chip through a pixel-level interconnect bonding layer; The MicroLED pixel array comprises m rows and n columns of pixel units, each pixel unit having an independent terminal and a common terminal; Each pixel unit's independent electrode is electrically connected to the pixel drive output of the CMOS driver chip through a corresponding connection point in the pixel-level interconnect bonding layer. The CMOS driver chip includes multiple independent power supply lines and multiple current source branches, each current source branch including a current source unit for providing driving current to the pixel unit; Each current source branch has its input terminal connected to at least one independent power supply line, and its output terminals are all connected to the connection point, which in turn connects to the independent electrode of the corresponding pixel unit. At least two current source branches are connected in parallel at the same connection point to provide the total driving current for the same pixel unit. The independent power supply lines connected to the current source branches that are connected in parallel at the same connection point are different.

2. The system according to claim 1, characterized in that, Each independent power supply line sets the drive current of each current source unit in a current load balancing manner.

3. The system according to claim 1, characterized in that, The number of independent power supply lines is k, where k≥m or k≥n; The input terminal of each current source branch is connected in parallel with multiple independent power supply lines through a power switch. The output terminals of multiple current source branches are connected to the independent terminals of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. Each pixel unit's CMOS driving area includes a selection switch matrix, which contains the power switch. The selection switch matrix is ​​used to control the on / off state of each power switch, thereby controlling the corresponding independent power supply line to supply power to the corresponding pixel unit.

4. The system according to claim 3, characterized in that, k=2m, the selection switch matrix is ​​used to select m independent power supply lines for odd-numbered rows to power odd-numbered row pixel units, and m independent power supply lines for even-numbered rows to power even-numbered row pixel units; or k=2n, the selection switch matrix is ​​used to select the independent power supply line of the odd column to power the n odd column pixel units, and select the independent power supply line of the even column to power the n even column pixel units.

5. The system according to claim 3, characterized in that, k=m, each independent power supply line runs in the row direction, and the input terminal of each current source branch is connected in parallel to each independent power supply line through a power switch. The output terminals of every m current source branches are connected to the independent terminal of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. The total number of current sources is m×m×n; or k=n, each independent power supply line runs in the column direction, each independent power supply line is connected in parallel to the input terminal of each current source branch through a corresponding power switch, and the output terminals of every n current source branches are connected to the independent terminal of the corresponding pixel unit after being aggregated at the connection point corresponding to the same pixel unit. The total number of current sources is n×m×n.

6. The system according to claim 3, characterized in that, The CMOS driver chip also includes a configuration controller, the input of which receives at least one of the following information: the illumination pattern distribution information of the MicroLED pixel array, and the temperature sensor distribution information on the MicroLED pixel array; The output of the configuration controller is connected to the control terminal of the selection switch matrix, and is used to dynamically adjust the combination of the effective power supply lines connected to each pixel unit. The effective power supply lines are independent power supply lines electrically connected to the corresponding pixel units.

7. The system according to any one of claims 1 to 6, characterized in that, The MicroLED pixel array has a common cathode structure, with the common electrode of all pixel units connected to a common ground VSS; the independent electrode of each pixel unit is the anode, and the independent power supply line is an independent VDD power supply line.

8. The system according to any one of claims 1 to 6, characterized in that, The MicroLED pixel array has a common anode structure, with the common terminal of all pixel units connected to a common power supply VDD; the independent terminal of each pixel unit is a cathode, and the independent power supply line is a VSS ground line.

9. The system according to any one of claims 1 to 6, characterized in that, Multiple current source units provide equal current values, or are weighted in binary or distributed according to a preset ratio; and / or The CMOS driver chip is a silicon-based CMOS driver chip; and / or The size of the pixel unit is 2μm. 100μm, pixel pitch is 2μm 100μm.

10. A MicroLED display device, characterized in that, The MicroLED pixel array power supply and driving system includes any one of claims 1 to 9.

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