Display Device Output Buffer Drivability for Variable Frame Power
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Solution Overview
Problem
Display devices face power consumption issues due to mismatches between rendering frame rates and refresh rates, leading to inefficiencies in normal and variable frame modes, particularly causing the tearing phenomenon when not synchronized.
Innovation Solution
A method is implemented in display devices to detect whether they are operating in normal or variable frame modes, adjusting output buffer drivability and slew rates accordingly, and setting polarity inversion types and charge sharing based on the detected mode to optimize power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the display device operates in variable frame mode with higher output buffer drivability and slew rates to handle variable content frame rates, then the ability to synchronize with variable rendering frame rates is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic adjustment of output buffer drivability and slew rates based on the detected frame mode. The system transitions from static configuration to dynamic adaptation, adjusting buffer drivability levels and slew rates according to whether normal mode or variable frame mode is detected, thereby optimizing power consumption while maintaining synchronization capability when needed
Solution Approach 2:
The patent changes key operational parameters (output buffer drivability, slew rate, bias current) based on the detected frame mode. By detecting whether the device is in normal mode or variable frame mode, the system adjusts these parameters accordingly - using higher drivability and slew rates only when variable frame mode is detected, and reducing them in normal mode to lower power consumption
2Use of energy by moving object
If the display device uses constant output buffer drivability and slew rates in normal mode, then power consumption is reduced, but the system cannot adapt when switching to variable frame mode
Solution Approach 1:
The patent implements preliminary detection of the frame mode before adjusting operational parameters. The timing controller detects whether normal mode or variable frame mode is being used, and based on this detection, pre-adjusts the output buffer drivability and slew rates accordingly. This preliminary action ensures the system is properly configured before actual data output, enabling both power savings in normal mode and adaptability when switching to variable frame mode
3Speed
If the display device maintains high bias current in output buffer amplifiers, then data signal slew rate is improved for variable frame mode, but power consumption increases
Solution Approach 1:
The patent directly addresses this contradiction by changing the bias current parameter based on the detected frame mode. When normal mode is detected, the system reduces bias current to lower power consumption while maintaining adequate slew rate. When variable frame mode is detected, the system increases bias current to provide higher slew rates needed for handling variable content frame rates, thus dynamically optimizing both speed and power consumption
Data Source
AI summary
A method of operating a display device involves detecting whether a frame mode of the display device is a normal mode in which image data are received with a constant frame rate or a variable frame mode in which the image data are received with a variable frame rate. An output buffer drivability of a data driver included in the display device may be set according to the detected frame mode, and an image is displayed by outputting data voltages corresponding to the image data with slew rates corresponding to the set output buffer drivability. Power consumption in output buffer amplifiers may be selectively lowered by setting a relatively low output buffer drivability corresponding to a relatively low slew rate.