Touch Driving Circuit Signal Delay Reduction via Reset Integration
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Solution Overview
Problem
Touch display devices face challenges in increasing touch driving frequency due to signal delay caused by impedance and noise, making it difficult to perform high-frequency touch sensing operations effectively.
Innovation Solution
A touch display device and driving method that reduce signal loss by overlapping the reset period of the touch driving circuit with the off period for blocking the touch sensing signal, using an integrating circuit and sample-and-hold circuit to generate and maintain a sensing output signal, and by connecting switches in a specific manner to optimize the integration time of the touch sensing signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the touch driving frequency is increased to improve touch sensing speed, then the touch sensing operation becomes more efficient, but signal delay increases due to impedance and noise
Solution Approach 1:
The integrating circuit performs preliminary integration of the touch sensing signal during the off-period of the touch driving signal, before the next sensing cycle begins. This preliminary action allows the signal to be processed in advance, reducing the effective delay in the touch sensing operation and enabling faster response times without increasing the driving frequency.
2Measurement precision
If the integration time of the touch sensing signal is increased to improve sensing quality, then the sensing precision improves, but the touch driving frequency must be reduced
Solution Approach 1:
The patent utilizes the off-period of the periodic touch driving signal to perform signal integration. By synchronizing the integration operation with the periodic off-period of the driving signal, the system achieves sufficient integration time for high precision sensing while maintaining the original touch driving frequency, thus resolving the contradiction between sensing precision and driving speed.
3Reliability
If the reset period of the touch driving circuit is separated from the off-period to ensure proper signal resetting, then the circuit reliability improves, but the integration time is reduced and signal loss increases
Solution Approach 1:
The patent merges the reset period of the touch driving circuit with the off-period of the touch driving signal. By combining these two periods into a single time window, the circuit achieves both proper signal resetting and maximum integration time, preventing signal loss while maintaining circuit reliability. This is accomplished by controlling the switching circuit to reset the integrating circuit during the off-period when no touch driving signal is present.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for reduced signal delay and increased integration time, enabling high-frequency touch sensing operations with improved quality and frequency of the touch driving signal.
Implementation Method 1
an integrating circuit for generating a sensing output signal by integrating a difference between the touch sensing signal and a reference voltage
Implementation Method 2
a sample-and-hold circuit for sampling the sensing output signal of the integrating circuit and maintaining the sampled voltage
Implementation Method 3
a feedback capacitor connected between an inverting input terminal and an output terminal of the operational amplifier
Data Source
AI summary
A touch display device comprises a display panel in which a plurality of touch electrodes including a plurality of X-touch electrodes extending to a first direction and a plurality of Y-touch electrodes extending to a second direction, and a plurality of subpixels are disposed; and a touch driving circuit supplying a touch driving signal to the display panel, sensing a touch by detecting a touch sensing signal, and overlapping with a turn-off section of a first switch transmitting the touch sensing signal and a turn-on section of a second switch resetting the touch sensing signal transmitted through the first switch.