Source Driver IC Flicker Prevention via Shared Reference Voltage
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Solution Overview
Problem
The existing source driver IC chips for display panels face issues with flicker in images due to variation in offset voltages among operational amplifiers, leading to increased power consumption and heat generation, especially when gradation voltage generating circuits are incorporated.
Innovation Solution
A source driver IC chip configuration that generates reference gradation voltages based on gamma characteristics, allowing these voltages to be shared among multiple chips, reducing the need for multiple operational amplifiers and minimizing variations in offset voltages, thereby preventing flicker and reducing power consumption and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If gradation voltage generating circuits are incorporated into each source driver IC chip, then the need for external circuits is eliminated and cost is reduced, but the chip size is increased by an amount corresponding to the incorporated circuits
Solution Approach 1:
The patent uses a resistance ladder circuit that generates multiple gradation voltages through voltage division, eliminating the need for multiple operational amplifiers. This copying approach replicates the voltage generation function through passive components rather than active circuits, significantly reducing chip area while maintaining the required functionality
Solution Approach 2:
The resistance ladder circuit serves multiple functions simultaneously: it generates reference gradation voltages, provides voltage division for multiple output levels, and eliminates the need for separate operational amplifiers for each voltage level. This multi-functionality reduces the overall circuit complexity and chip size
2Ease of manufacture
If gradation voltage generating circuits are incorporated into each source driver IC chip, then the need for external circuits is eliminated and cost is reduced, but power consumption and heat generation are increased
Solution Approach 1:
The patent replaces active operational amplifier circuits with passive resistance ladder circuits for voltage generation. Passive components consume significantly less power and generate less heat compared to active amplification circuits, thereby reducing overall power consumption while maintaining the gradation voltage generation function
Solution Approach 2:
The patent extracts the essential function of voltage division and reference voltage generation from complex operational amplifier circuits, implementing it through a simpler resistance ladder structure. This extraction removes unnecessary active components that contribute to power consumption and heat generation
3Reliability
If multiple operational amplifiers are used in each source driver IC chip, then gradation voltages can be generated, but variation in offset voltages among operational amplifiers causes flicker in displayed images
Solution Approach 1:
The patent uses a single resistance ladder circuit to generate all reference gradation voltages simultaneously, eliminating the need for multiple operational amplifiers. This single-source approach ensures that all voltage outputs are derived from the same reference, preventing offset voltage variations and the resulting image flicker
Solution Approach 2:
The patent merges the functions of multiple operational amplifiers into a single resistance ladder circuit. By combining voltage generation and division functions into one passive circuit structure, the patent eliminates the variability introduced by multiple active components while maintaining the required voltage output levels
Data Source
AI summary
A source driver IC chip, designed to prevent flicker in images displayed on a display panel while suppressing power consumption and heat generation, includes: a reference gradation voltage generating part (220) configured to generate a reference gradation voltage based on a first or second gamma characteristic of the display panel, using first and second power supply voltages (VH) and (VL) inputted through first and second external terminals (PA2, PA3); and a third external terminal (PA4) for externally outputting said reference gradation voltage. The source driver IC chip further includes first and second gradation voltage generating parts configured to generate first and second gradation voltages respectively, using a reference gradation voltage based on a first gamma characteristic inputted through a fourth external terminal and a reference gradation voltage having a second gamma characteristic inputted through a fifth external terminal respectively.