Touch Driving Circuit Differential Sensing Single-Ended Amplifier
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Solution Overview
Problem
Existing touch display devices face challenges in simultaneously performing display driving and touch driving due to time-division methods, which result in insufficient image quality and touch sensitivity, with the touch sensing function often being affected by display driving and vice versa.
Innovation Solution
A touch display device incorporating a touch driving circuit with a first current conveyor and a second current conveyor, along with a single-ended amplifier, that differentially senses touch electrodes to accurately detect touches without interference from display driving, while reducing the number of circuit components and area required for differential sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time-division driving method is used to separate display driving and touch driving, then interference between the two functions is reduced, but both display driving time and touch driving time become insufficient, deteriorating image quality and touch sensitivity
Solution Approach 1:
The patent implements simultaneous driving of display and touch functions, allowing both operations to occur continuously without time division. The touch driving circuit operates independently during the entire display driving period, eliminating the time loss inherent in sequential time-division methods while maintaining touch sensing accuracy through differential sensing techniques.
2Reliability
If time-division driving method is used to separate display driving and touch driving, then interference between the two functions is reduced, but both display driving time and touch driving time become insufficient, deteriorating image quality and touch sensitivity
Solution Approach 1:
The patent enables continuous display driving without interruption for touch sensing operations. By implementing simultaneous driving where the touch driving circuit operates in parallel with the display driving circuit, the full display driving time is utilized for image rendering, eliminating the time reduction that would occur with time-division multiplexing.
3Productivity
If display driving and touch driving are performed simultaneously, then sufficient driving time for both functions is provided, but touch driving is affected by display driving, reducing or eliminating touch sensing capability
Solution Approach 1:
The patent extracts and removes the display driving interference from the touch sensing signal path through differential sensing. By using a differential amplifier that subtracts the common-mode display signal from the touch sensing signal, the harmful display driving interference is taken out, leaving only the genuine touch signal for accurate detection.
Solution Approach 2:
The differential amplifier acts as an intermediary that processes both the touch sensing signal and display driving signal simultaneously. It mediates between these two signals by performing differential amplification, allowing the touch signal to be extracted from the combined signal while the display driving continues uninterrupted.
4Productivity
If display driving and touch driving are performed simultaneously, then sufficient driving time for both functions is provided, but display driving is affected by touch driving, significantly deteriorating image quality
Solution Approach 1:
The differential sensing circuit extracts and removes the touch driving interference from the display signal path. By configuring the differential amplifier to subtract the touch driving signal component from the combined signal, the harmful touch interference is taken out, preserving image quality while maintaining simultaneous operation.
5Measurement precision
If differential sensing is implemented to sense touch accurately without display driving influence, then touch sensing accuracy is improved, but the number of circuit components and circuit area increase
Solution Approach 1:
The patent merges the touch driving function and differential sensing function into a single integrated touch driving circuit. The same circuit that generates touch driving signals also performs differential sensing by utilizing the differential amplifier configuration, eliminating the need for separate dedicated sensing components and reducing overall circuit complexity.
Solution Approach 2:
The touch driving circuit is designed with multi-functionality, serving both as a signal generator for touch electrodes and as a differential sensing amplifier. This universal circuit performs multiple functions including signal output, signal reception, and differential amplification, reducing the total number of components needed while maintaining high touch sensing accuracy.
Data Source
AI summary
Embodiments of the present disclosure relate to a touch display device, a touch driving circuit, and a touch sensing method, and enable differential sensing using a single-ended amplifier without using a differential amplifier, thereby not only accurately sensing a touch during display driving, but also significantly reducing the number of circuit components and the circuit area for differential sensing.