Touch Display Driving Circuit for Load-Free Gate Voltage Toggling
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Solution Overview
Problem
Existing driving circuits for in-cell touch display panels struggle to provide load-free driving functions due to the inability to toggle gate voltages effectively, which is necessary for overcoming parasitic capacitances in touch sensors, while maintaining stable voltage levels during display operations.
Innovation Solution
A driving circuit design incorporating switches, multiplexers, and capacitors that allow gate output signals to toggle during touch periods without affecting the stability of voltage levels during display periods, using a power integrated circuit that can be sourced from a third-party manufacturer without modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate voltages are toggled during touch periods to overcome parasitic capacitances, then load-free driving function is improved, but voltage stability during display periods deteriorates
Solution Approach 1:
The patent segments the operating periods into distinct display periods and touch periods, with separate control strategies for each. During display periods, gate voltages remain stable; during touch periods, they toggle to overcome parasitic capacitances. This temporal segmentation resolves the contradiction by allowing different voltage behaviors in different operational contexts.
Solution Approach 2:
The patent implements dynamic control of gate voltages through switches (first switch and second switch) that are turned on or off based on the operational period. The controller dynamically adjusts the gate output signals to provide stability during display operations while enabling toggling during touch operations, thus adapting the system behavior to current operational requirements.
2Adaptability or versatility
If control signals are adjusted into varying voltage levels for touch sensing, then touch sensing function is improved, but voltage level stability for display function deteriorates
Solution Approach 1:
The patent employs periodic action by alternating between display periods with stable voltage levels and touch periods with varying voltage levels. The controller periodically switches between these two operational modes, allowing the system to maintain voltage stability when displaying while enabling voltage variation when sensing touch, thus resolving the contradiction through time-division multiplexing.
Solution Approach 2:
The system dynamically adjusts control signal voltage levels based on operational mode. During display periods, voltage levels remain fixed; during touch periods, they vary to enable sensing. This dynamic adaptation is achieved through the controller's management of switch states and modulation signals, allowing the system to optimize performance for the current operational context.
3Reliability
If switches are added to enable gate voltage toggling, then load-free driving capability is improved, but device complexity increases
Solution Approach 1:
The patent makes existing components multi-functional. The first switch and second switch serve dual purposes: they control gate voltage toggling during touch periods while also maintaining stability during display periods. The controller integrates multiple functions (generating modulation signals, controlling switches, managing timing) into a single unit, reducing overall system complexity despite adding switching capability.
Solution Approach 2:
The patent merges the voltage control function into the existing display driver circuitry. Rather than adding a separate voltage control system, the controller integrates switch control and gate voltage management into its existing architecture, combining multiple functions into unified control logic and reducing the need for additional independent components.
Data Source
AI summary
A driving circuit, for driving a touch display panel, includes a controller, a first switch and a second switch. The controller is configured to provide a first modulation signal, a second modulation signal, a first control signal and a second control signal. The first switch is a first node. The first node is configured for providing a first gate output signal to the touch display panel. The first switch is turned on or turned off by the first control signal. The second switch is coupled to a second node. The second node is configured for providing a second gate output signal to the touch display panel. The second switch is turned on or turned off by the second control signal.