Touch Sensor Threshold Sequencing for Low-Power Contact Detection
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Solution Overview
Problem
Existing touch sensors struggle to accurately detect touch contacts while maintaining low power consumption, especially in devices that require frequent state changes between active and low-power modes.
Innovation Solution
A method and sensor configuration that utilize a capacitor to detect touch contacts by comparing voltages across the capacitor with multiple thresholds, allowing for efficient detection and minimizing power consumption by transitioning out of low-power mode only when a valid touch contact is confirmed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single voltage threshold is used for touch detection, then the detection process is simple and fast, but the accuracy of touch contact detection is reduced leading to false positives
Solution Approach 1:
The single voltage threshold comparison is segmented into two sequential steps: first comparing the voltage with a first voltage threshold, and if that threshold is reached within a first duration threshold, then comparing the voltage with a second voltage threshold (higher than the first). This segmentation allows the system to maintain simplicity while improving detection accuracy by filtering out false positives through the two-stage verification process.
2Speed
If the device exits low-power mode frequently to check for touch contacts, then touch detection responsiveness is improved, but power consumption increases
Solution Approach 1:
The device implements periodic touch detection during low-power operating mode by regularly implementing the two-step voltage threshold comparison method. This allows the device to remain in low-power mode longer while still detecting touch contacts periodically, thus balancing responsiveness with power consumption. The device only exits low-power mode when a valid touch contact is confirmed through both threshold comparisons.
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
The solution effectively reduces power consumption by ensuring that devices only exit low-power mode when a reliable touch contact is detected, while also enhancing the accuracy of touch contact detection by using multiple voltage thresholds.
Implementation Method 1
the voltage is the voltage across a capacitor
Data Source
AI summary
An embodiment of the present disclosure relates to a method of detection of a touch contact by a sensor including a first step of comparison of a voltage with a first voltage threshold; and a second step of comparison of the voltage with a second voltage threshold, the second step being implemented if the first voltage threshold has been reached within a duration shorter than a first duration threshold, the second voltage threshold being higher than the first voltage threshold.