Source Driver Polarity Control for LCD Common Voltage Stability
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Solution Overview
Problem
Conventional charge sharing technologies in source drivers for liquid crystal displays are unable to effectively reduce power consumption, especially as display sizes increase and new driving methods are adopted, leading to instability in common voltage due to variations in pixel voltage.
Innovation Solution
A source driver with a data register unit and polarity determining units that adjust the polarity of pixel voltages based on received and previous display data, using charge sharing units to manage charging directions and execute charge sharing functions, thereby minimizing the influence on common voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pixel voltage is varied to display different grayscale levels, then display brightness is improved, but common voltage stability deteriorates due to capacitance coupling effect
Solution Approach 1:
The patent implements dynamic polarity inversion control where the polarity of pixel voltages is dynamically adjusted based on frame number and line number parameters. The source driver selectively inverts polarities of pixel voltages applied to different data groups in different time periods, creating a dynamic compensation mechanism that counteracts the capacitance coupling effect and stabilizes common voltage while maintaining display brightness variations.
2Area of stationary object
If display size is increased, then display area is improved, but power consumption increases due to more pixel voltages being provided
Solution Approach 1:
The patent divides the display panel into multiple data groups (first data group, second data group, etc.) with each group containing multiple data channels. This segmentation allows independent polarity control for different groups, enabling selective inversion strategies that reduce overall power consumption while maintaining display performance across large display areas.
Solution Approach 2:
The patent implements periodic polarity inversion where the polarity of pixel voltages is inverted at specific time periods based on frame numbers and line numbers. This periodic action creates a charge sharing effect between adjacent data groups, reducing the net charge transfer required and thereby lowering power consumption in large displays.
3Use of energy by moving object
If conventional charge sharing technology is used, then power consumption reduction is achieved in dot inversion driving, but it becomes ineffective for new driving methods
Solution Approach 1:
The patent creates a universal polarity control mechanism that can adapt to different driving methods (dot inversion, line inversion, block inversion, etc.). The control unit determines polarity inversion based on frame number and line number parameters, making the charge sharing effect applicable across various driving methods rather than being limited to dot inversion only.
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
The solution stabilizes common voltage by dynamically adjusting pixel voltage polarities and enabling charge sharing, reducing power consumption and improving display performance.
Implementation Method 1
a variation of a voltage level can be conducted to the common electrode through a capacitance coupling effect of the storage capacitor
Data Source
AI summary
A source driver and a method for determining polarity of pixel voltage thereof are provided. The source driver includes a data register unit, a plurality of data groups and a plurality of polarity determining units. The data register unit receives an image data signal and provides a plurality of display data. The data groups have at least two data channels respectively. The data channels are coupled to the data register unit to receive the corresponding display data and provide a plurality of pixel voltages. The polarity determining units are respectively coupled to the data channels corresponding to different data groups, and each of the polarity determining units determines whether to invert polarities of a part of the pixel voltages provided by the coupled data channels according to the received display data of the coupled data channels and previous display data corresponding to the received display data.