Source Driver Time-Division Output for Lower-Power PENTILE Displays
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Solution Overview
Problem
Existing display devices with PENTILE™ pixel structures face challenges in reducing power consumption during operation.
Innovation Solution
A source driver that includes a digital-to-analog converter and output buffers to alternately output color data voltages during horizontal periods, controlled by a controller to minimize power consumption, and a demultiplexer to selectively transfer these voltages to sub-data lines, optimizing the driving method for PENTILE™ pixel structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a PENTILE pixel structure is used with multiple color sub-pixels connected to data lines, then display coverage and color rendering are improved, but power consumption increases due to sequential voltage supply requirements
Solution Approach 1:
The source driver sequentially outputs different color data voltages (red, green, blue) during different time periods within a horizontal scanning period. The controller manages the output buffer to switch between voltage levels corresponding to different colors at specific timing intervals, enabling the single data line to serve multiple color sub-pixels while maintaining distinct color signals through time-division multiplexing
Solution Approach 2:
A single data line is designed to carry multiple color data voltages sequentially rather than requiring separate dedicated data lines for each color. The output buffer is configured to generate different voltage levels (e.g., first voltage for red, second voltage for green, third voltage for blue) that can be supplied to the same data line at different times, making the data line universal for driving all color sub-pixels
2Device complexity
If data voltages are supplied sequentially to sub-pixels sharing a data line, then device complexity is reduced, but image display quality deteriorates due to timing constraints and voltage switching overhead
Solution Approach 1:
The controller pre-calculates and manages the timing sequence for supplying different color data voltages to the output buffer before the actual voltage switching occurs. The controller generates control signals that prepare the output buffer for sequential voltage outputs in advance, ensuring smooth transitions and maintaining image quality by coordinating voltage supply timing with the horizontal scanning period
Solution Approach 2:
The output buffer is designed to dynamically switch between different voltage levels corresponding to different colors based on real-time control signals from the controller. The buffer can adaptively adjust its output voltage (first voltage, second voltage, or third voltage) during the horizontal period to match the required color signal, enabling flexible and high-quality image display despite the sequential supply method
Data Source
AI summary
A source driver includes a digital-to-analog converter that converts signals corresponding to first and second colors included in digital image data into first and second analog color data voltages, respectively, an output buffer unit including a first output buffer that alternately outputs the first color data voltage and the second color data voltage during one horizontal period, and a controller that controls the digital-to-analog converter and the first output buffer to alternately output the first color data voltage and the second color data voltage corresponding to each horizontal period for each horizontal period. The controller controls the first output buffer such that the second color data voltage is output after the first color data voltage is first output during a first horizontal period, and the first color data voltage is output after the second color data voltage is first output during a subsequent second horizontal period.