Touch Display Driving Circuit Voltage Level Control
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Solution Overview
Problem
Touch display devices face challenges in simultaneously executing display driving and touch driving without interfering with each other, leading to image defects and reduced touch sensitivity due to the complexity of timing control and the need for expensive components, especially when touch sensors are embedded in the display panel.
Innovation Solution
A touch display device with a driving circuit that includes a display controller, gate driving circuit, data driving circuit, and touch driving circuit, where the touch electrode driving signal's voltage level varies in sections other than the high-level periods of the ON-clock or OFF-clock signals, allowing for simultaneous stable execution of display and touch driving, and the touch electrode driving signal can have varying frequencies and duty ratios to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-division driving system is used to separate display driving and touch driving, then interference between the two functions is reduced, but timing control complexity increases and both driving times become insufficient
Solution Approach 1:
The patent merges display driving and touch driving into a single time period, eliminating the need for separate time slots. The display controller simultaneously generates both display driving signals and touch driving signals, and the display panel simultaneously performs both display and touch sensing functions, thereby reducing timing control complexity while maintaining functional stability
Solution Approach 2:
The patent dynamically adjusts the voltage level of touch electrode driving signals based on the display driving state. When display driving is in a high-level period, touch driving uses a different voltage level, and when display driving is in a low-level period, touch driving uses another voltage level. This dynamic adjustment allows both functions to share the same time period without interference
2Reliability
If time-division driving system is used, then functional separation is achieved, but image quality and touch sensitivity decrease due to insufficient driving time
Solution Approach 1:
The patent implements continuous display driving without interruption. Display driving and touch driving both occur during the same time period, eliminating the dead time present in time-division systems. This continuous operation maintains full image quality and touch sensitivity while achieving functional separation through voltage level differentiation rather than temporal separation
3Ease of manufacture
If touch sensors are embedded in display panel, then integration is improved, but interference between display driving and touch driving increases
Solution Approach 1:
The patent applies different voltage levels to different functions within the same time period. When display driving is active at a high voltage level, touch electrode driving uses a different voltage level, and vice versa. This local differentiation of electrical characteristics allows embedded touch sensors to coexist with display circuitry without mutual interference
Solution Approach 2:
The display controller acts as an intermediary that coordinates both display driving signals and touch driving signals. It generates both types of signals and manages their voltage levels to prevent interference, enabling the display panel to simultaneously perform display and touch sensing functions without the touch sensors being affected by display driving signals
Data Source
AI summary
A touch display device, a driving circuit, and a driving method are provided. An image defect which occurs when display driving and touch driving are simultaneously executed can be reduced by performing control such that a voltage level of a touch electrode driving signal (TDS) varies in a section other than a high-level period (Pon) of an ON-clock signal (ON_CLK) and/or a high-level period (Poff) of an OFF-clock signal (OFF_CLK).