Source Driver Chopper Circuit for Display Gamma Nonlinearity
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Solution Overview
Problem
Source drivers in display apparatuses face nonlinearity issues in driving voltage output due to differential difference amplifiers, leading to unsmooth gamma color levels, which affect display quality.
Innovation Solution
A source driver with a chopper circuit that adjusts gray-scale data of temporally or spatially adjacent sub-pixels by adding or deducting values to generate new gray-scale data, which are then used to produce driving voltages, effectively offsetting nonlinearity errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a differential difference amplifier (DDA) is applied in a source driver to process more data bits and reduce DAC circuit area, then the circuit area is reduced, but the interpolated voltage output becomes nonlinear resulting in unsmooth gamma color levels
Solution Approach 1:
The patent applies gamma correction in advance to the input gray-scale data before it reaches the DDA circuit. By pre-processing the digital data to compensate for the expected nonlinearity, the final output voltage achieves linear gamma characteristics despite the inherent nonlinearity of the DDA interpolation process
Solution Approach 2:
The patent modifies the input data parameters by applying gamma correction transformation to the gray-scale data bits. This changes the distribution and weighting of the digital codes fed to the DDA, compensating for the nonlinearity and achieving smooth gamma color levels in the output
Data Source
AI summary
A source driver and an operation method thereof are provided. The source driver includes a chopper circuit and a source driver circuit. A first sub-pixel and a second sub-pixel are temporally or spatially adjacent to each other. The chopper circuit adds original gray-scale data of the first sub-pixel with a first value to serve as new gray-scale data of the first sub-pixel and deducts original gray-scale data of the second sub-pixel by a second value to serve as new gray-scale data of the second sub-pixel. The source driver circuit generates a first driving voltage for the first sub-pixel according to the new gray-scale data of the first sub-pixel and generates a second driving voltage for the second sub-pixel according to the new gray-scale data of the second sub-pixel.