Display Driver Circuit Hybrid Capacitive Voltage Driving
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Solution Overview
Problem
As display device resolutions increase, amplifier circuits in drivers face challenges in writing data voltages within the required time, leading to accuracy issues and increased power consumption due to the need for higher bias voltages, and capacitive driving methods suffer from data voltage accuracy drops due to external capacitance ratios being difficult to set accurately.
Innovation Solution
A driver configuration that includes a capacitor driving circuit, a capacitor circuit, and a voltage driving circuit, where capacitive driving is initiated first to quickly settle data voltage, followed by voltage driving to achieve high accuracy, with a switching circuit to disconnect amplifier output and use high-speed capacitive driving, and a reference voltage generation circuit to generate internal reference voltages for accurate data voltage output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If amplifier circuits are used to drive pixels at high speeds, then writing time is reduced, but power consumption increases due to higher bias voltages required
Solution Approach 1:
The patent segments the pixel driving process into two distinct phases: a first period using amplifier circuits for high-speed initial writing, and a second period using capacitor charge redistribution for power-efficient maintenance. This temporal segmentation allows the system to achieve both high writing speed and low power consumption by using each method only when necessary.
Solution Approach 2:
The amplifier circuit performs preliminary action by completing the majority of the voltage writing task during the first period before the capacitor-based charge redistribution takes over in the second period. This preliminary high-speed charging eliminates the need for continuous high-power amplifier operation, thereby reducing overall power consumption.
2Use of energy by moving object
If capacitor charge redistribution is used for driving, then power consumption is reduced, but data voltage accuracy deteriorates due to external capacitance ratio variations
Solution Approach 1:
The amplifier circuit performs preliminary action by completing the majority of the voltage writing task during the first period before the capacitor-based charge redistribution takes over in the second period. This preliminary high-speed charging eliminates the need for continuous high-power amplifier operation, thereby reducing overall power consumption.
Solution Approach 2:
The patent segments the pixel driving process into two distinct phases: a first period using amplifier circuits for high-speed initial writing, and a second period using capacitor charge redistribution for power-efficient maintenance. This temporal segmentation allows the system to achieve both high writing speed and low power consumption by using each method only when necessary.
3Measurement precision
If resolution of electro-optical panel is increased, then display quality is improved, but pixel driving time becomes shorter making it difficult to write data voltages accurately
Solution Approach 1:
The patent replaces the traditional single amplifier-based voltage writing mechanism with a hybrid system that combines amplifier circuits and capacitor charge redistribution. This substitution enables the system to achieve both high-speed initial charging and accurate final voltage establishment within the reduced time budget imposed by high-resolution displays.
Solution Approach 2:
The patent segments the pixel driving process into two distinct phases: a first period using amplifier circuits for high-speed initial writing, and a second period using capacitor charge redistribution for power-efficient maintenance. This temporal segmentation allows the system to achieve both high writing speed and low power consumption by using each method only when necessary.
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 approach allows for high-accuracy data voltage output while reducing power consumption by leveraging capacitive driving's speed and internal voltage generation, improving image quality and adaptability across various electro-optical panel configurations.
Implementation Method 1
a capacitor circuit including first to nth capacitors C1 to Cn provided between the first to nth capacitor driving nodes NDR1 to NDRn and a data voltage output terminal TVQ
Data Source
AI summary
In a display device having a driver that drives load lines in an electro-optical panel through capacitor charge redistribution, a data voltage is determined by a capacitance ratio during capacitive driving. However, a panel-side capacitance is a capacitance external to a driver IC, and thus it is difficult to set the capacitance ratio exactly. Accordingly, voltage driving, which outputs a data voltage corresponding to tone data to a data voltage output terminal using a voltage driving circuit, is carried out after capacitive driving that drives the electro-optical panel has been started.