Integrated Touch Display Driving Circuit Noise Reduction
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Solution Overview
Problem
Existing touch display devices face challenges in minimizing chip size and power consumption due to separate driving circuits for display and touch sensing functions, which complicates design, especially in small-sized devices like mobile displays, and suffer from noise in touch sensing data, affecting accuracy.
Innovation Solution
A driving circuit with a group of amplifiers and a feedback capacitor, where the feedback capacitor is selectively coupled with amplifiers during touch driving periods to generate load-free driving voltage, reducing noise and improving accuracy, and integrated within the data driving circuit to share channels for both display and touch functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate driving circuits are provided for display function and touch sensing function, then each function can be independently driven, but chip size and power consumption are increased
Solution Approach 1:
The patent combines the display driving circuit and touch sensing circuit into a single integrated driving circuit. The data driving circuit is configured to perform both display data output and touch sensing signal output, eliminating the need for separate driving circuits and thereby reducing chip size while maintaining independent driving capability for both functions.
Solution Approach 2:
The data driving circuit is designed with multi-functionality to serve both display and touch sensing operations. By configuring the same circuit to output different types of signals (display data and touch sensing signals) at different times or through different channels, the patent achieves universal functionality without requiring additional dedicated circuits, thus reducing overall chip area.
2Reliability
If separate driving circuits are provided for display function and touch sensing function, then each function can be independently driven, but power consumption is increased
Solution Approach 1:
The patent merges the display driving and touch sensing driving functions into a single power-efficient circuit architecture. By sharing common circuit elements and power supply paths where possible, and by coordinating the operation timing of display and touch functions, the integrated driving circuit reduces overall power consumption compared to having completely separate driving circuits operating independently.
3Measurement precision
If feedback capacitor is electrically coupled with amplifier during touch driving period, then touch sensing accuracy is improved by reducing noise, but circuit complexity is increased
Solution Approach 1:
The patent implements dynamic switching of the feedback capacitor's electrical coupling state. The feedback capacitor is selectively coupled to the amplifier only during the touch driving period when touch sensing is performed, and decoupled during other periods. This dynamic configuration improves touch sensing accuracy by reducing noise when needed, while maintaining simpler circuit operation during non-touch periods, thus balancing accuracy improvement with circuit complexity management.
4Ease of operation
If load-free driving voltage is generated externally, then touch driving can be performed, but additional components and increased device complexity are required
Solution Approach 1:
The patent implements self-service by enabling the data driving circuit to generate its own load-free driving voltage internally during touch driving periods. The circuit uses its existing amplifier and feedback capacitor components to produce the necessary driving voltage without requiring external voltage sources or additional dedicated voltage generation circuits, thereby achieving touch driving capability while minimizing device complexity.
Data Source
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AI summary
A touch display device and a driving circuit (300) are disclosed in which the driving circuit (300) is included in the touch display device. The driving circuit (300) may be capable of reducing a chip size and power consumption by configuring an amplifier disposed in an output terminal of a data voltage to be electrically coupled with a feedback capacitor (Cfb) through a switch, and enabling both display driving and touch sensing to be performed through ON/OFF control of the switch. Further, the accuracy and performance of touch sensing may be improved by adjusting an ON/OFF operation of a switch and the number of amplifiers electrically coupled with the feedback capacitor (Cfb), and a circuit structure for touch driving may be further simplified by generating a load-free driving voltage output in a touch driving period using the amplifiers and a digital-to-analog converter within the driving circuit (300).