Dynamic Sync Signal Generator for LCD Power Optimization
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Solution Overview
Problem
Conventional liquid crystal display (LCD) drivers operate at a fixed frequency of 60 Hz, regardless of the image type, leading to higher than necessary power consumption when displaying static images.
Innovation Solution
A display apparatus and method that includes a mode determiner to compare image frames, a sync signal generator to produce a low-frequency sync signal based on the image mode, and drivers to adjust the data and gate lines accordingly, allowing for reduced frequency operation suitable for static images, thereby optimizing power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the driver operates at a fixed frequency of 60 Hz, then the display can show both static and moving images, but power consumption increases when displaying static images
Solution Approach 1:
The driver frequency is made dynamic rather than fixed. The system automatically adjusts the driving frequency based on the image type detected by the mode determiner, switching between normal frequency (60 Hz) for moving images and low frequency (e.g., 24 Hz) for static images, thereby optimizing power consumption while maintaining display versatility
Solution Approach 2:
The operating frequency parameter is changed based on image mode. The sync signal generator produces different frequency signals (normal frequency for moving images, low frequency for static images) according to the image type determined by the mode determiner, enabling adaptive power management
2Reliability
If the driver uses normal frequency for all image types, then display quality is maintained, but power consumption cannot be optimized for static images
Solution Approach 1:
The system dynamically adjusts frequency based on image content. The mode determiner continuously monitors the displayed image and switches the driver frequency accordingly, ensuring high display quality for moving images while reducing frequency (and power consumption) for static images
Solution Approach 2:
The mode determiner provides feedback about the image type to the sync signal generator, which then adjusts the driving frequency. This closed-loop feedback mechanism ensures that power consumption is optimized while maintaining display quality through continuous monitoring and adaptive adjustment
3Use of energy by moving object
If low frequency operation is implemented, then power consumption is reduced, but charging period differences between data voltages of positive and negative polarities occur
Solution Approach 1:
The system uses periodic frame period alternation to balance charging periods. By alternating between first frame periods and second frame periods in a sequential manner, the system creates periodic charging opportunities for both positive and negative polarity data voltages, ensuring charge balance while maintaining low frequency operation
Solution Approach 2:
The sync signal generator preliminarily arranges the frame periods in a specific sequence (first, second, second, first) to pre-establish balanced charging conditions before data voltage switching occurs, ensuring that charging period differences are compensated in advance
Data Source
AI summary
A display apparatus includes a mode determiner configured to compare image signals of a previous frame and a current frame and to determine an image mode of the current frame, a sync signal generator configured to generate a panel sync signal with a low frequency corresponding to the image mode using an original sync signal with a normal frequency, the low frequency being a non-divisor frequency of the normal frequency and lower than the normal frequency, a data driver configured to drive a data line of a display panel using a data sync signal based on the panel sync signal with the low frequency, and a gate driver configured to drive a gate line of the display panel using a gate sync signal based on the panel sync signal with the low frequency.