LED Driving Apparatus Using Digital-to-Analog Converters for Micro-LED Arrays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LED driving circuits face challenges in achieving steady state quickly enough to maintain display quality, as they require time to reach steady state shorter than the minimum time unit, affecting the performance of micro-LED arrays.
Innovation Solution
The proposed LED driving apparatus incorporates digital-to-analog converters and data latch circuits to generate driving currents for LED arrays, allowing for time-divisional output of driving currents to sequentially drive each LED row, utilizing sub-driving current generating circuits with switching and current source devices to produce currents corresponding to bit orders in pixel data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional digital gray level modulation scheme is used with timing modulation, then luminance steps can be achieved, but the time to reach steady state must be shorter than the minimum time unit which compromises display quality
Solution Approach 1:
The patent segments the pixel data into multiple bit components (e.g., 3-bit pixel data into individual bit signals). Each bit is processed separately through dedicated current generating circuits, allowing parallel current generation without timing constraints. This segmentation eliminates the need for rapid sequential switching while maintaining precise luminance control through binary-weighted current summation.
Solution Approach 2:
The patent replaces the mechanical timing-based switching system with an electrical current summation system. Instead of using time-division multiplexing where currents are switched sequentially, the invention uses multiple current sources that are electrically summed through parallel connections. This substitution eliminates the timing constraint entirely, as electrical currents can be combined instantaneously without mechanical switching delays.
2Measurement precision
If each micro-LED is driven by a corresponding current driver in one-to-one configuration, then each LED can be precisely controlled, but the circuit complexity and area increase significantly
Solution Approach 1:
The patent merges multiple current driving functions into a single integrated circuit unit. Instead of having separate current drivers for each LED, the invention combines multiple bit-processing circuits and current generating circuits within one driver unit that serves multiple LEDs. This merging reduces the overall number of discrete driver circuits while maintaining precise control through the binary-weighted current summation mechanism.
Solution Approach 2:
The patent designs the current driver to perform multiple functions within a single circuit structure. The same driver circuit can drive multiple LEDs by processing different bit combinations for different pixels. The circuit achieves universal functionality by using shared current generating circuits that can be selectively activated based on the pixel data bits, eliminating the need for dedicated drivers for each LED.
3Adaptability or versatility
If time-divisional output of driving currents is used to sequentially drive LED rows, then scalability is improved, but the control complexity increases
Solution Approach 1:
The patent implements periodic action through time-divisional output where driving currents are sequentially provided to different LED rows in repeating time intervals. Each row receives its driving current during a specific time period, and this pattern repeats for all rows. This periodic operation enables scalable driving of large LED arrays by simply extending the time sequence, while the underlying current generation mechanism remains unchanged and simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the need for rapid steady state achievement, enhancing display quality by optimizing current generation and distribution, and allows for easy scalability and control of the LED driving apparatus.
Implementation Method 1
Each of the digital-to-analog converters is configured to output a driving current according to n-bits pixel data to drive the corresponding LED
Implementation Method 2
The current source device is configured to generate the sub-driving current. The current source device is a current source transistor, and the current source devices of the digital-to-analog converter are respectively controlled by n bias voltages so as to output the n sub-driving currents corresponding to different bit orders
Implementation Method 3
Each of the sub-driving current generating circuits includes a switching device and a current source device. The switching device is electrically coupled to the power rail
Implementation Method 4
Each of the digital-to-analog converters is electrically coupled to a corresponding LED of the LED array
Implementation Method 5
The light emitting diode (micro-LED) array is generally driven by current drivers
Data Source
AI summary
An LED driving apparatus for driving an LED array including a plurality of digital-to-analog converters and a plurality of data latch circuits is provided. Each of the digital-to-analog converters is coupled to a corresponding LED, and outputs a driving current according to n-bits pixel data to drive the corresponding LED. Each of the plurality of data latch circuits stores the n-bits pixel data, and is coupled to a corresponding digital-to-analog converter to control the n-bits pixel data to be written into the corresponding digital-to-analog converter. Each of digital-to-analog converters includes n sub-driving current generating circuits. Each of the n sub-driving current generating circuits generates a sub-driving current having a current value corresponding to a bit order of a bit of the n-bits pixel data. The driving current is generated by summing up n sub-driving currents.