Display Source Control Circuit for Distance-Based EMI Reduction
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Solution Overview
Problem
High-speed driving methods for high-resolution displays suffer from electromagnetic interference (EMI) due to the switching operations of output switches in display driving ICs, which deteriorate the EMI characteristics.
Innovation Solution
A display device with a source control circuit that adjusts the on-slew and off-slew rates of the output control signal based on the distance between display areas and the source driver, using a buffer control circuit to operate buffers differently for each area, thereby reducing the delay periods and improving EMI characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed driving method is used for high-resolution displays, then productivity and resolution are improved, but electromagnetic interference deteriorates
Solution Approach 1:
The patent applies local quality by differentiating the slew rate control based on display area distance. Display areas are divided into first and second areas, with the second area (farther from source driver) receiving a higher slew rate than the first area. This localized differentiation optimizes EMI reduction where most needed while maintaining signal integrity across the entire display panel.
Solution Approach 2:
The patent changes the slew rate parameter of the output control signal based on distance. By adjusting the slew rate (a temporal parameter) according to the spatial position of display areas, the system dynamically optimizes signal characteristics to reduce EMI while maintaining high-speed operation capability.
2Speed
If output switches are switched rapidly for high-speed signal supply, then data transmission speed is improved, but electromagnetic interference increases
Solution Approach 1:
The patent modifies the slew rate parameter of the output control signal to reduce EMI while maintaining signal transmission speed. By controlling the rate of change of the control signal, the patent reduces high-frequency components that cause EMI without significantly impacting the overall data transmission speed.
Solution Approach 2:
The patent introduces dynamic slew rate control that adapts to different display areas based on their distance from the source driver. This dynamic adjustment allows the system to optimize EMI reduction in real-time across different spatial zones while maintaining high-speed operation.
3Device complexity
If uniform slew rate control is applied to all display areas, then device complexity is reduced, but EMI reduction effectiveness decreases
Solution Approach 1:
The patent implements local quality control by dividing the display panel into multiple areas with different slew rate requirements. This regional differentiation improves EMI reduction effectiveness without introducing excessive complexity, as the control strategy is based on simple distance-based categorization rather than complex per-pixel control.
Solution Approach 2:
The patent segments the display area into first and second display areas based on distance from the source driver. This segmentation enables differentiated slew rate control, improving EMI reduction where needed while keeping the control architecture manageable through clear spatial boundaries.
Data Source
AI summary
Some example embodiments provides a display device including: a display panel on which a plurality of data lines are positioned; a source driver including a plurality of output switches connected to the plurality of data lines and supplying a plurality of data signals to the plurality of data lines during a period in which the plurality of output switches are turned on by an output control signal; and a source control circuit that differently controls an on-slew rate of the output control signal for each of a plurality of display areas of the display panel according to a distance between each display area and the source driver.