Touch Circuit Signal Sequencing for False Touch Prevention
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Solution Overview
Problem
In touch display devices, unstable signal timings during communication between the system motherboard and the display panel control circuit board can lead to abnormal touch function failures, especially when the device is in a sleep state and false touches occur due to external contacts.
Innovation Solution
A touch circuit and driving system that includes a touch IC, pull-up sub-circuits, switching sub-circuits, and a logic sub-circuit with an AND gate, which controls signal transmission to prevent premature activation of the touch IC, ensuring stable signal communication and normal operation by sequencing signal inputs to the data and clock ports.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the touch IC is activated early to enable touch function, then the touch responsiveness is improved, but signal timing instability occurs during communication between motherboard and display panel control circuit board
Solution Approach 1:
The patent applies preliminary action by activating the touch IC before the display panel controller, allowing the touch IC to be ready to receive touch signals earlier. This is achieved through a start signal generation circuit that generates a start signal for the touch IC based on a power-on reset signal, while the display panel controller waits for additional clock signals. This preliminary activation improves touch responsiveness without compromising communication stability because the touch IC is prepared in advance but only processes valid signals when timing is correct.
Solution Approach 2:
The patent implements dynamics by making the activation timing of different components flexible and adaptive. The touch IC can be activated at different times relative to the display panel controller depending on the signal timing conditions. The system dynamically adjusts the activation sequence based on whether the touch IC receives properly timed data and clock signals, allowing optimal performance across different operating conditions while maintaining communication reliability.
2Speed
If signal transmission is accelerated to improve response time, then communication speed is improved, but false touches occur due to unstable signal timing
Solution Approach 1:
The patent applies feedback by monitoring the timing relationship between data signals and clock signals received by the touch IC. The system includes a detection mechanism that verifies whether the data signal arrives within the expected time window relative to the clock signal. If the timing is incorrect (indicating unstable communication), the system can detect this and prevent false touch processing, thereby eliminating false touches while maintaining fast communication speed when timing is proper.
3Adaptability or versatility
If the touch circuit is activated during sleep state to maintain touch functionality, then touch availability is improved, but abnormal failures occur due to unstable signal conditions
Solution Approach 1:
The patent applies preliminary action for sleep state operation by pre-configuring the touch IC activation logic to respond to power-on reset signals even during sleep state. The start signal generation circuit is designed to activate the touch IC early in the power-on sequence, including during sleep state transitions. This preliminary preparation allows the touch IC to be available during sleep state while the system includes timing verification mechanisms to ensure stable operation only when proper signal timing is established.
Data Source
AI summary
A touch circuit includes: a touch IC; a first pull-up sub-circuit; a second pull-up sub-circuit; a first switching sub-circuit configured to transmit a signal from a data signal input terminal to a data signal port under control of a signal from a first signal input terminal; and a second switching sub-circuit configured to transmit a signal from a clock signal input terminal to a clock signal port under control of the signal from the first signal input terminal. The signal from the data signal input terminal is transmitted to the first switching sub-circuit earlier than the signal from the first signal input terminal, and the signal from the clock signal input terminal is transmitted to the second switching sub-circuit earlier than the signal from the first signal input terminal.