Semiconductor Display Driver Voltage Fluctuation Cancellation
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Solution Overview
Problem
Existing display drivers for liquid crystal display panels suffer from image quality deterioration due to voltage fluctuations in the common voltage, which cannot be effectively canceled by the delay caused by inverted amplification circuits, leading to unsuppressed image quality issues.
Innovation Solution
A semiconductor apparatus that includes a gradation voltage generation portion generating representative gradation voltages based on gamma characteristics, a driving portion selecting appropriate gradation voltages, and a fluctuating voltage superposition portion that generates voltage fluctuations in the gradation voltages to match power supply voltage fluctuations, thereby canceling these fluctuations and suppressing image quality deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an inverted amplification circuit is used to generate correction voltage, then the common voltage fluctuation can be detected, but the response is delayed and cannot suppress head portion voltage fluctuations
Solution Approach 1:
The patent applies preliminary action by generating the correction voltage in advance through the D/A converter before the voltage fluctuation occurs in the common voltage. The D/A converter converts digital correction data to analog correction voltage proactively, so that when the common voltage fluctuates, the correction is already prepared and can be immediately applied without delay from amplification circuits.
2Adaptability or versatility
If the common voltage fluctuation is reflected in the gradation voltage, then the voltage fluctuation can be tracked, but image quality deteriorates
Solution Approach 1:
The patent converts the harmful effect of common voltage fluctuation into a beneficial correction mechanism. By detecting the common voltage fluctuation and generating a corresponding correction voltage through the D/A converter, the system transforms the harmful voltage variation into a useful correction signal that is applied to the gradation voltage, thereby canceling the original fluctuation and improving image quality.
3Reliability
If correction voltage is applied to cancel common voltage fluctuation, then image quality can be maintained, but the correction must be timely to avoid head portion fluctuations
Solution Approach 1:
The patent replaces the mechanical amplification circuit system with an electronic D/A converter system. Instead of using an inverted amplification circuit that introduces delay, the system uses digital-to-analog conversion to generate correction voltage directly from digital correction data. This substitution eliminates the response delay inherent in amplification circuits and enables timely correction of voltage fluctuations.
Data Source
AI summary
A semiconductor apparatus including a driver capable of favorably suppressing image deterioration accompanying a voltage fluctuation even if the voltage fluctuation is generated in a display device is provided. The semiconductor apparatus of the disclosure includes: a gradation voltage generation portion generating a first to kth representative gradation voltage in accordance with gamma characteristics and generating a first to Nth gradation voltage based on the first to kth representative gradation voltage; a driving portion selecting one gradation voltage corresponding to display data from the first to Nth gradation voltage and applying a signal representing the selected one gradation voltage as a driving signal to source lines; and a fluctuating voltage superposition portion generating, when a voltage fluctuation is generated in the power supply voltage for making display cells emit light, a voltage fluctuation corresponding to the voltage fluctuation in at least one of the first to kth representative gradation voltage.