Display Panel Precharge Circuit for Power Reduction
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Solution Overview
Problem
Display apparatuses consume excessive power due to repetitive changes in grayscale voltage levels, leading to increased power consumption and potential display artifacts caused by differences in precharge voltages between pixels.
Innovation Solution
A method and apparatus for driving a display panel that involves outputting a precharge voltage during a first duration of a horizontal period, followed by a grayscale voltage during a second duration, with the precharge voltage being initialized during the second duration, using a precharge circuit with capacitors and switches to connect pixels to buffers, and setting the precharge voltage to a middle grayscale voltage for reduced power consumption and improved display quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If grayscale voltages are repetitively increased and decreased to display repetitive patterns, then display functionality is maintained, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by precharging pixels to a middle grayscale voltage level before displaying the actual image content. This precharge operation prepares the pixels in advance, so that when grayscale voltages need to change, the transitions require less energy. The precharge voltage is set to a middle level (e.g., 128 grayscale level) that serves as a starting point, reducing the magnitude of subsequent voltage changes and thereby reducing power consumption during normal display operations.
2Reliability
If precharge voltage is not initialized, then device complexity is reduced, but display artifacts occur due to differences in precharge voltages between pixels
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the precharge voltage level based on the actual image content being displayed. The initialization circuit calculates the average grayscale voltage of the current frame and sets the precharge voltage accordingly. This dynamic parameter adjustment ensures that precharge voltages across all pixels remain consistent and match the actual display requirements, preventing display artifacts while maintaining system simplicity through software-based control rather than complex hardware circuits.
3Use of energy by moving object
If precharge voltage is set to extreme levels (max or min), then power consumption is reduced, but display quality deteriorates due to inconsistent grayscale output
Solution Approach 1:
The patent applies equipotentiality by setting the precharge voltage to a middle grayscale level (equipotential point) rather than extreme levels. This middle voltage level serves as a balanced reference point that minimizes the energy required for voltage transitions in both directions (increasing or decreasing grayscale). By establishing this equipotential precharge state, the system achieves both low power consumption and consistent grayscale output quality across all pixels.
Data Source
AI summary
A method of driving a display panel includes, a data driver outputting a precharge voltage to a plurality of pixels of the display panel during a first duration of a horizontal period, the data driver outputting a grayscale voltage to the pixels of the display panel during a second duration of the horizontal period and the data driver initializing the precharge voltage during the second duration of the horizontal period.