Touch Sensor Driving Circuit Noise Measurement via Time Division
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Solution Overview
Problem
Existing touch sensor technologies face challenges in efficiently measuring noise, which affects the signal-to-noise ratio (SNR), leading to increased measurement time and current consumption due to the need for repeated application of touch sensor driving signals.
Innovation Solution
A method that time-divides the touch sensor driving period into a touch input sensing portion and a noise measurement portion, where two or more touch sensors are short-circuited to simultaneously measure noise, reducing measurement time and current consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a touch sensor driving signal is repeatedly applied to measure noise, then noise measurement accuracy is improved, but measurement time and current consumption increase
Solution Approach 1:
The patent applies periodic action by time-dividing the touch sensor driving period into distinct portions: a touch input sensing portion and a noise measurement portion. During the noise measurement portion, the system repeatedly applies touch sensor driving signals at specific frequencies to measure noise levels, while during the touch input sensing portion, normal touch sensing operations are performed. This periodic alternation allows accurate noise measurement without continuously occupying the touch sensor, thereby reducing overall measurement time while maintaining noise measurement accuracy.
Solution Approach 2:
The patent segments the touch sensor driving period into functionally distinct portions: a touch input sensing portion for normal touch operations and a noise measurement portion for noise characterization. This segmentation allows the system to perform noise measurement only during dedicated time windows rather than continuously, reducing the overall measurement time and current consumption while still achieving accurate noise measurements through repeated signal application within the noise measurement portion.
2Measurement precision
If a touch sensor driving signal is repeatedly applied to measure noise, then noise measurement accuracy is improved, but current consumption increases
Solution Approach 1:
The patent reduces current consumption by applying the touch sensor driving signal only periodically during the noise measurement portion rather than continuously. The system alternates between a touch input sensing portion where normal operations occur and a noise measurement portion where repeated signal application takes place. This periodic approach maintains noise measurement accuracy through sufficient signal repetitions while significantly reducing the overall current consumption compared to continuous signal application.
Solution Approach 2:
The patent segments the operating cycle into a touch input sensing portion and a noise measurement portion, confining the high-current repeated signal application to only the noise measurement portion. This segmentation ensures that the repeated application of touch sensor driving signals occurs only when necessary for noise characterization, thereby maintaining measurement accuracy while minimizing the total current consumption across the entire operating cycle.
3Measurement precision
If noise measurement is performed continuously, then SNR improvement is achieved, but measurement time increases
Solution Approach 1:
The patent implements periodic noise measurement by alternating between touch input sensing portions and noise measurement portions. During the noise measurement portion, the system measures noise affecting the touch sensor by analyzing the difference between maximum and minimum values from repeated measurements. This periodic approach achieves SNR improvement through adequate noise characterization while maintaining high productivity by quickly completing measurements and returning to normal touch sensing operations, rather than continuously occupying the system for noise measurement.
Data Source
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AI summary
Disclosed herein are a method and circuit for driving touch sensors (Cs) and a display device using the same. A method of driving touch sensors (Cs) includes supplying a touch sensor driving signal (VMOD) to the touch sensors (Cs) or an amplifier (PREAMP) and sensing a touch input during a touch input sensing portion (TT1) and measuring current noise received through the touch sensors (Cs) without the touch sensor driving signal (VMOD) during a noise measurement portion (TT2).