Level Voltage Circuit Feedback for Uniform Display Gradation
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Solution Overview
Problem
In active matrix drive display apparatuses, variations in output voltages among data driver ICs cause display unevenness due to inaccuracies in the level voltage generation circuit, leading to issues with multi-gradation, higher definition, and image quality.
Innovation Solution
A level voltage generation circuit that uses N differential amplifiers and a resistor ladder with N voltage supply points and M voltage output points to generate M level voltages, suppressing variations by separating voltage supply and output points and incorporating feedback circuits to minimize the impact of contact resistance variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional level voltage generation circuit is used in data driver ICs, then the circuit structure is simple, but voltage variations occur among different data driver ICs causing display unevenness
Solution Approach 1:
The voltage generation circuit is segmented into multiple independent differential amplifiers, each responsible for generating a specific level voltage. This segmentation allows each amplifier to be optimized independently for precision while maintaining overall circuit functionality, thereby reducing voltage variations among data driver ICs without excessive complexity
Solution Approach 2:
Feedback circuits are incorporated into the differential amplifier structure to stabilize the generated level voltages. The feedback mechanism compensates for manufacturing variations and environmental factors, ensuring high voltage precision across different data driver ICs while maintaining a manageable circuit structure through systematic error correction
2Manufacturing precision
If the number of level voltages is increased for higher definition display, then display quality improves, but the complexity of the voltage generation circuit increases
Solution Approach 1:
Each differential amplifier is designed with universal functionality to generate multiple level voltages through configurable feedback networks. This multi-functionality allows a single amplifier structure to serve multiple purposes, enabling higher definition display with more level voltages without proportionally increasing circuit complexity
Solution Approach 2:
The circuit employs a nested structure where feedback circuits are integrated within the differential amplifier blocks, and multiple amplifiers are organized in a hierarchical arrangement. This nesting allows the circuit to generate increased numbers of level voltages for higher definition display while maintaining compact and manageable complexity through systematic organization
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively reduces voltage variations among data driver ICs, ensuring uniform display quality by generating highly precise level voltages with minimal relative and absolute errors, thereby improving display uniformity and image quality.
Implementation Method 1
N differential amplifiers having output ends, which receive the N input voltages respectively, amplify the N input voltages respectively and output amplified N input voltages
Implementation Method 2
a resistor ladder having N voltage supply points respectively connected to the output ends of the N differential amplifiers and M voltage output points for outputting the M level voltages
Data Source
AI summary
A level voltage generation circuit, a data driver and a display are provided. The level voltage generation circuit generates, based on N different input voltages, M (M>N) level voltages. The level voltage generation circuit comprises N differential amplifiers having output ends, which receive the N input voltages respectively, amplify the N input voltages respectively and output amplified N input voltages, and a resistor ladder having N voltage supply points respectively connected to the output ends of the N differential amplifiers and M voltage output points for outputting the M level voltages. The resistor ladder comprises a first wiring, connected to the output end of one of the N differential amplifiers through one of the N voltage supply points; and a second wiring, connected between one of the M voltage output points and one of an input pair of one of the N differential amplifiers.