Gamma Voltage Driving Circuit With Op-Amp Offset Elimination
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Solution Overview
Problem
Existing display devices, particularly LED display devices, face challenges in achieving accurate luminance due to offset voltages in operational amplifiers, which hinder precise grayscale implementation.
Innovation Solution
A data driving circuit employing a mixed driving method that combines auto-zeroing and chopping techniques to eliminate offset voltages in operational amplifiers, ensuring accurate luminance by using offset elimination circuits in gamma voltage generation circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a gamma voltage generation circuit uses operational amplifier circuits to distribute power supply voltage and generate gamma reference voltage, then luminance control capability is improved, but offset voltage in operational amplifiers degrades grayscale accuracy
Solution Approach 1:
The patent extracts and eliminates the offset voltage component from the operational amplifier circuits through dedicated offset elimination circuits. These circuits separately process and remove offset voltages from each operational amplifier, allowing the main gamma voltage generation function to maintain high luminance control while achieving accurate grayscale representation.
Solution Approach 2:
The patent segments the offset elimination process by providing separate offset elimination circuits for each operational amplifier circuit (first, second, and third operational amplifiers). This segmentation allows independent compensation of offset voltages in each stage of the gamma voltage generation, improving overall grayscale accuracy without compromising luminance control capability.
2Measurement precision
If multiple operational amplifier circuits are used to eliminate offset voltages at different locations of resistor string, then grayscale accuracy is improved, but circuit complexity increases
Solution Approach 1:
The patent merges the offset elimination function with the existing operational amplifier circuits by integrating offset elimination circuits into the gamma voltage generation structure. Each offset elimination circuit is combined with its corresponding operational amplifier, allowing offset compensation without requiring completely separate compensation systems, thus managing complexity while achieving accurate grayscale.
Solution Approach 2:
The patent introduces offset elimination circuits as intermediary components between the operational amplifiers and the resistor string. These intermediary circuits specifically target and eliminate offset voltages without interfering with the main gamma voltage generation function, providing a structured approach to complexity management while achieving the desired precision.
Data Source
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AI summary
The disclosure relates to an offset elimination operation of an internal operational amplifier of a data driving circuit and relates to a technique that applies different offset elimination methods for each position of an operational amplifier.