Digital Gamma Circuit White Color Coordinate Adjustment
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Solution Overview
Problem
Conventional digital gamma circuits face challenges in reducing chip area and power consumption while adjusting white color coordinates, primarily due to limitations in chip size and the absence of a function for adjusting white color coordinates.
Innovation Solution
A digital gamma circuit that sets gamma curve values for R, G, and B, allowing for the adjustment of white color coordinates by adding an offset value to specific Y-axis points, and reduces chip area and power consumption by setting X-axis points at intervals of a square of 2, eliminating the need for a divider through a shift operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a digital gamma circuit is configured to select a gamma voltage corresponding to each gray level, then the brightness uniformity is improved, but the chip area increases beyond acceptable limits
Solution Approach 1:
The gamma voltage selection is segmented into two parts: a common gamma voltage selected based on gray level, and a color-specific offset voltage added to adjust for R, G, B differences. This segmentation allows the circuit to achieve per-color gamma correction without requiring separate gamma voltage tables for each color, thus reducing chip area while maintaining brightness uniformity.
Solution Approach 2:
The patent merges the gamma voltage selection function with the color correction function by combining a common gamma voltage (selected based on gray level) with color-specific offset voltages. This merging allows the circuit to perform both functions using a unified structure, reducing the overall chip area compared to having separate circuits for each function.
2Area of stationary object
If conventional digital gamma circuits are used, then the chip area is reduced, but the function for adjusting white color coordinates is lost
Solution Approach 1:
The digital gamma circuit is designed with multi-functionality by incorporating offset voltage adders that can adjust gamma voltages for R, G, B colors independently. This universal structure allows the same circuit to perform both standard gamma correction and white color coordinate adjustment, maintaining small chip area while gaining adaptability for different display requirements.
Solution Approach 2:
The circuit introduces dynamic adjustability through offset voltage parameters that can be modified to change white color coordinates. By making the offset voltages可调 (adjustable), the circuit can adapt to different display panels and color standards without requiring a complete redesign, thus maintaining small chip area while achieving versatility.
3Measurement precision
If X-axis points are set at non-square-interval values, then the gamma curve precision is improved, but the chip area and power consumption increase due to the need for a divider
Solution Approach 1:
The patent extracts the complex division operation from the gamma curve calculation and replaces it with a lookup table approach. By pre-calculating and storing gamma values in a table indexed by square-interval X-axis points, the circuit eliminates the need for a divider, reducing chip area and power consumption while maintaining adequate gamma curve precision through the lookup table interpolation.
4Measurement precision
If complex gamma calculation algorithms are used, then the gamma curve accuracy is improved, but the power consumption and chip area increase
Solution Approach 1:
Instead of performing complex real-time gamma calculations, the patent uses a lookup table that contains pre-calculated gamma values. This copying approach stores the results of complex calculations in advance, allowing the circuit to retrieve gamma values through simple table lookup operations, thereby maintaining gamma curve accuracy while dramatically reducing power consumption and eliminating the need for complex calculation logic.
Data Source
AI summary
Disclosed are a digital gamma circuit capable of reducing a chip area and adjusting white color coordinates, and a source driver including the same. The digital gamma circuit may include a digital gamma algorithm for setting a gamma curve for each R, G, or B. Through the digital gamma algorithm, values of X-axis points of the gamma curve may be set, values of Y-axis points of the gamma curve corresponding to the values of the X-axis points may be set, and a value of at least one Y-axis point indicative of white among the values of the Y-axis points may be adjusted by adding an offset value thereto.