Integrated Driving Circuit Common Voltage Compensation for Display Devices
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Solution Overview
Problem
In display devices with in-cell touch sensors, the limited distance between the flexible printed circuit board (FPCB) and the input terminal of the integrated driving circuit due to VESA standard constraints results in uneven common voltage distribution, causing block dimming and reduced display quality.
Innovation Solution
The implementation of a pair of common voltage compensation circuits within the integrated driving circuit, activated based on image patterns and controlled by an external controller, to compensate for common voltage deviations and maintain uniform voltage distribution across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the integrated driving circuit is positioned close to the FPCB to satisfy VESA standard size limitations, then the device size is reduced, but the common voltage distribution becomes uneven causing block dimming
Solution Approach 1:
The patent divides the common voltage compensation function into multiple independent compensation circuits distributed at different locations within the integrated driving circuit. Each compensation circuit independently compensates for voltage drops in its local region, ensuring uniform voltage distribution across the entire display panel while maintaining a compact circuit layout that satisfies VESA standard size limitations.
Solution Approach 2:
The patent implements location-specific compensation by placing compensation circuits at strategic positions within the integrated driving circuit. Each compensation circuit is tailored to compensate for voltage drops in its specific regional area, allowing the circuit to maintain compact size while achieving uniform common voltage distribution across different regions of the display panel.
2Device complexity
If power is supplied only to one side of the integrated driving circuit to satisfy input requirement resistance, then the circuit complexity is reduced, but the common voltage deviation increases causing block dimming
Solution Approach 1:
The patent segments the power supply configuration by providing power input terminals at multiple locations (both left and right sides) of the integrated driving circuit. This segmentation allows each region of the circuit to receive adequate power, reducing voltage drops and ensuring uniform common voltage distribution without requiring complex multi-channel power management systems.
Solution Approach 2:
The patent achieves equipotentiality across the integrated driving circuit by strategically positioning power input terminals and compensation circuits to balance voltage distribution. This ensures that all regions of the circuit operate at appropriate voltage levels, preventing block dimming while maintaining relatively simple power supply configuration.
3Adaptability or versatility
If the common voltage is supplied through a long trace to reach the integrated driving circuit, then the circuit layout flexibility is improved, but the voltage drop increases causing block dimming
Solution Approach 1:
The patent segments the common voltage supply path by providing multiple power input terminals at different locations of the integrated driving circuit. This segmentation shortens the effective trace length from any point on the panel to the nearest power input, reducing voltage drops while maintaining layout flexibility to accommodate different panel designs and satisfy VESA standards.
Solution Approach 2:
The patent introduces compensation circuits as intermediary elements between the power input terminals and the common voltage output nodes. These compensation circuits actively detect and correct voltage drops in real-time, ensuring uniform voltage distribution even when trace lengths vary due to layout constraints, thus maintaining both layout flexibility and voltage uniformity.
Data Source
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AI summary
A display device having a touch sensor includes a display panel displaying an image, a touch screen positioned inside the display panel, and an integrated driving circuit outputting a common voltage during a display driving period for displaying an image on the display panel and outputting a touch driving signal during a touch screen driving period for sensing the touch screen. The integrated driving circuit a data driving circuit outputting a data signal to the display panel, and a pair of touch screen driving circuits positioned separately from the data driving circuit and configured to output the touch driving signal to the touch screen. The pair of touch screen driving circuits includes a pair of common voltage compensation circuits activated or inactivated in response to an active signal output from an external controller.