Touch Controller Clock Calibration for Sensing Stability
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Solution Overview
Problem
Touch controllers in touch screen devices face misrecognition issues due to variations in touch sensing periods caused by internal and external environmental changes, leading to confusion between finger taps and presses.
Innovation Solution
A touch controller is designed with a first clock generator for generating a low frequency clock signal and a second clock generator for generating a high frequency clock signal, along with a calibration circuit that adjusts the low frequency clock signal's frequency using the high frequency clock signal, to maintain a consistent touch sensing period and prevent misrecognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a low frequency clock signal is used to calculate the touch sensing period, then power consumption is reduced, but the touch sensing period varies due to frequency drift
Solution Approach 1:
The patent changes the frequency parameter of the clock signal dynamically. A low frequency clock signal is used during idle periods to minimize power consumption, while a high frequency clock signal is used during active touch sensing operations to ensure accurate timing. The system transitions between these frequency states based on operational requirements, thus resolving the contradiction between power savings and timing stability.
Solution Approach 2:
The patent implements dynamic frequency adjustment of the clock signal based on the operational state of the touch controller. The system switches between low frequency mode (for power saving during idle periods) and high frequency mode (for accurate touch sensing during active operations). This dynamic adaptation allows the system to optimize both power consumption and timing accuracy at different operational stages.
2Measurement precision
If the touch sensing period varies due to environmental changes, then misrecognition of touch occurs, but increasing clock frequency to stabilize timing increases power consumption
Solution Approach 1:
The patent implements periodic touch sensing operations where the system alternates between idle periods (using low frequency clock for power saving) and active sensing periods (using high frequency clock for accurate measurement). During idle periods, the touch controller enters a low-power state, and during active periods, it switches to high frequency operation to perform precise touch detection. This periodic switching resolves the contradiction by limiting high-power operation to only when necessary for accurate measurement.
3Measurement precision
If a high frequency clock signal is used for touch sensing operation, then touch sensing accuracy is improved, but power consumption increases
Solution Approach 1:
The patent implements dynamic frequency adjustment of the clock signal based on the operational state of the touch controller. The system switches between low frequency mode (for power saving during idle periods) and high frequency mode (for accurate touch sensing during active operations). This dynamic adaptation allows the system to optimize both power consumption and timing accuracy at different operational stages.
Data Source
AI summary
A touch controller, a touch screen device, and an operating method of the touch controller are provided. A touch controller, performing a touch sensing operation of sensing a touch of a touch panel in a touch sensing period, includes a first clock generator configured to generate a low frequency clock signal for calculating the touch sensing period, a second clock generator configured to generate a high frequency clock signal for performing the touch sensing operation, and a first calibration circuit configured to calibrate a frequency of the low frequency clock signal by using the high frequency clock signal.