Regulator Feedback Circuit for Touch Display Settle Time
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Solution Overview
Problem
In full in-cell touch panel architectures, far-end common electrode blocks experience longer settle times due to increased resistance-capacitance loading, leading to display abnormalities and sensor edge stripes, as the time for display driving is compressed to accommodate touch sensing.
Innovation Solution
An integrated circuit with a regulator is used, where the input terminal's coupling node is positioned near the common electrode to reduce settle time by employing a feedback voltage mechanism, allowing for quicker stabilization of the common voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the common electrode is positioned far from the TDDI integrated circuit, then the touch sensing coverage is improved, but the settle time of the common voltage becomes longer causing display abnormalities
Solution Approach 1:
A feedback voltage terminal is coupled to the far-end common electrode to create a local feedback mechanism. This feedback path allows the regulator to sense and correct voltage deviations at the remote electrode location, enabling faster settling time without requiring the electrode to be positioned close to the TDDI integrated circuit, thus maintaining both large touch sensing coverage and short settle time
2Productivity
If the display driving time is compressed to spare time for touch sensing, then the touch sensing capability is improved, but the common voltage cannot be pulled back to target voltage within the limited time
Solution Approach 1:
The feedback voltage terminal is configured to receive feedback from the far-end common electrode during the display driving period, enabling the regulator to proactively adjust and pull back the common voltage to the target voltage before the touch sensing period begins. This preliminary voltage stabilization ensures that even with compressed display driving time, the common voltage reaches its target level in time, maintaining both touch sensing capability and voltage stability
3Length of stationary object
If the resistance-capacitance loading of the VCOM line is large, then the voltage transmission to far-end electrodes is achieved, but the settle time increases causing sensor edge stripes
Solution Approach 1:
By coupling the feedback voltage terminal directly to the far-end common electrode, the patent creates a localized feedback control loop that compensates for the RC loading effects of long VCOM lines. The feedback mechanism continuously monitors and corrects voltage deviations at the remote end, enabling fast settling despite the large resistance-capacitance loading inherent in long transmission lines, thus preventing sensor edge stripes
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 configuration significantly shortens the settle time of the common electrode, preventing display abnormalities and sensor edge stripes by ensuring the common voltage is pulled back to the target voltage within the limited display driving time.
Implementation Method 1
An input terminal of the regulator is coupled to a second node different from the first node to receive a feedback voltage
Data Source
AI summary
An integrated circuit and a touch display apparatus are provided. The integrated circuit is configured to drive a touch display panel. The integrated circuit includes a regulator. An output terminal of the regulator is employed as a first node to output a common voltage, wherein the common voltage is configured to be provided to at least one common electrode of the touch display panel. An input terminal of the regulator is coupled to a second node different from the first node to receive a feedback voltage.