Source Driver Adaptive Gamma Driving Structure
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Solution Overview
Problem
Existing source drivers for self-luminous display panels, such as OLEDs, face challenges in generating suitable data voltage ranges for different colors due to their unique conversion characteristics, leading to limitations in brightness variations and image quality.
Innovation Solution
A novel source driver design incorporating a digital-to-analog converter (DAC) structure with multiple sub-DACs, an interpolation circuit, and a switch circuit, allowing for the generation of different data voltage ranges for each color by selectively connecting sub-DACs and performing interpolation based on specific control signals, enabling the use of a single gamma voltage generation circuit for various colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single gamma voltage generation circuit is used for all colors, then device complexity is reduced, but it becomes difficult to generate appropriate data voltages for different colors with different conversion characteristics
Solution Approach 1:
The DAC is divided into multiple sub-DACs, each responsible for generating voltage segments for different color ranges. The switch circuit selects and connects appropriate sub-DACs based on the color being driven, enabling a single gamma voltage generation circuit to produce color-specific data voltages through segmented processing
Solution Approach 2:
The switch circuit dynamically reconfigures the DAC structure by connecting different sub-DACs and interpolation circuits based on the color signal (RGB). This dynamic reconfiguration allows the same hardware to adapt its voltage generation characteristics for each color without requiring separate dedicated circuits
2Adaptability or versatility
If separate gamma voltage generation circuits are used for each color, then adaptability to different color characteristics is improved, but device complexity and cost increase
Solution Approach 1:
A single DAC structure with multiple sub-DACs and interpolation circuits serves multiple color channels (RGB). The switch circuit enables this universal structure to be configured for different color characteristics, making one circuit perform the function of what would traditionally require three separate circuits
Solution Approach 2:
The switch circuit acts as an intermediary that receives color information and configures the DAC accordingly. It mediates between the universal DAC structure and the color-specific requirements, selecting appropriate sub-DACs and interpolation levels to generate the correct voltage range for each color
3Device complexity
If fixed data voltage ranges are used for all colors, then device complexity is reduced, but brightness variations and image quality deteriorate due to different luminous efficiencies
Solution Approach 1:
Different sub-DACs generate voltage ranges optimized for specific color characteristics. The switch circuit connects the appropriate sub-DAC based on the color being driven, ensuring that each color receives a voltage range matched to its luminous efficiency characteristics, thereby optimizing brightness variations for each color
Data Source
AI summary
A source driver includes a first DAC for driving a first-color subpixel and a second DAC for driving a second-color subpixel. Each DAC is configured to output at least one output voltage according to an N-bit data code, and includes a plurality of sub-DACs, an interpolation circuit and a switch circuit. Each sub-DAC receives m bits of the N-bit data code and generates a set of intermediate voltages accordingly. The interpolation circuit performs an interpolation on a selected set of intermediate voltages according to k bits of the N-bit data code and at least one interpolation control signal, to generate the output voltage. The switch circuit electrically connects the interpolation circuit and a selected sub-DAC which outputs the selected set of intermediate voltages. The interpolation circuit of the first DAC and the interpolation circuit of the second DAC respectively perform the interpolation according to different numbers of interpolation bits.