Peak-Voltage Touch Sensing for Rapid Time-Domain Differential Detection
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Solution Overview
Problem
Existing touch input detection methods are burdensome in terms of computing resources, particularly when rapid measurements are required for time domain differential processing.
Innovation Solution
Systems and methods that measure peak voltage at an electrode over a measurement period and defer digital signal processing until after peak electrode capacitance has been sampled, suitable for capacitive sensors using self-capacitance and mutual capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If digital signal processing is performed on each electrode output as it is sampled, then touch input detection can be performed, but computing resources are excessively consumed and measurement speed is limited
Solution Approach 1:
The patent applies preliminary action by performing peak detection on electrode outputs before digital signal processing. The measurement circuit identifies peak voltages of capacitive coupling signals and holds these peak values, allowing subsequent time domain differential processing to operate on pre-processed data rather than raw continuous signals. This reduces the computational burden and enables faster measurement cycles.
Solution Approach 2:
The patent extracts only the essential information (peak voltage values) from the full electrode output signals. By using peak detectors to capture only the maximum voltage points and holding circuits to maintain these values, the system removes unnecessary signal data before processing, significantly reducing the amount of data that requires digital signal processing while preserving the touch detection functionality.
2Speed
If rapid measurements are required for time domain differential processing, then touch detection responsiveness improves, but computing resources become overwhelmed
Solution Approach 1:
The measurement circuit performs preliminary peak detection and signal holding before the data reaches the time domain differential processing stage. This pre-processing prepares the data in advance, allowing the main processing circuit to operate at higher speeds without being bottlenecked by raw signal processing requirements, thereby reducing the energy needed for rapid measurements.
Solution Approach 2:
By extracting only peak voltage information from continuous electrode signals, the patent reduces the data volume that requires energy-intensive digital processing. This extraction approach enables faster measurement rates while consuming less computing energy, as the time domain differential processor works with discrete peak values rather than continuous waveforms.
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
Conserves computing resources and enables rapid touch input detection by minimizing digital signal processing, suitable for capacitive sensors, buttons, track pads, and touch screens.
Implementation Method 1
a stimulus voltage to a capacitive coupling. The measurement circuit includes a measurement capacitor, and in particular a strobe electrode capacitively coupled to a sense electrode
Implementation Method 2
The measurement circuit includes a peak detector and provides an output proportional to the peak voltage across the capacitive coupling
Data Source
AI summary
Systems and methods for determining a touch input are provided. The systems and methods generally include measuring the peak voltage at an electrode over a measurement period and determining a touch input based on the peak voltage. The systems and methods can conserve computing resources by deferring digital signal processing until after a peak electrode capacitance has been sampled. The systems and methods are suitable for capacitive sensors using self-capacitance and capacitive sensors using mutual capacitance. The systems and methods are also suitable for capacitive buttons, track pads, and touch screens, among other implementations.