Oscillator Sensing Circuit for Low-Power Strain Button Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional strain or pressure sensing methods require continuous monitoring, consuming significant power and are not suitable for low-power applications, particularly in battery-powered devices, and often rely on physical buttons with moving parts that may be undesirable due to cost, durability, or design considerations.
Innovation Solution
A sensing circuit utilizing a hysteretic comparator and loop filter that outputs an oscillation signal, where the loop filter's electrical property varies with the physical property of interest, allowing for low-power detection of strain or pressure through a change in oscillation frequency, enabling button press detection without mechanical buttons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous strain or pressure sensing is implemented, then reliable detection of applied force is achieved, but power consumption increases significantly
Solution Approach 1:
The sensing circuit implements periodic sensing through an oscillator that generates oscillation signals at specific frequencies. The oscillator is activated in periodic intervals rather than continuously, allowing the system to detect strain or pressure events only when needed. This periodic operation mode significantly reduces power consumption while maintaining reliable detection capability for button press events.
Solution Approach 2:
The patent replaces mechanical continuous monitoring systems with an electronic oscillator-based sensing system. The oscillator converts physical strain or pressure changes into frequency variations of an electrical signal, eliminating the need for continuous power-intensive mechanical sensing mechanisms while maintaining detection reliability.
2Ease of operation
If physical buttons with moving parts are used, then clear user interaction indication is provided, but device complexity and durability issues arise
Solution Approach 1:
The patent replaces mechanical buttons with moving parts with a strain or pressure sensing circuit that detects force applied to a defined area. The sensing circuit uses an oscillator to convert physical pressure into electrical frequency signals, eliminating mechanical components while providing clear indication of user interaction through detectable frequency changes.
Solution Approach 2:
The patent introduces a strain or pressure sensor as an intermediary between the user's physical interaction and the electronic system. The sensor mediates the conversion of mechanical pressure into electrical signals that can be processed by the oscillator and decoder, providing a bridge between physical and electronic domains without requiring direct mechanical linkages.
3Adaptability or versatility
If touchscreen is enabled continuously for touch sensitivity, then user interaction options increase, but power consumption increases
Solution Approach 1:
The sensing circuit enables touch sensitivity through periodic oscillator activation rather than continuous operation. The oscillator generates detection signals in periodic intervals, allowing the system to maintain touch sensitivity capability while consuming significantly less power compared to continuous touchscreen operation. This periodic sensing approach allows the device to wake from low-power states using the physical button area without requiring continuous touchscreen engagement.
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 solution provides low-power, reliable detection of applied strain or pressure, reducing power consumption and eliminating the need for physical buttons with moving parts, while maintaining user experience through haptic feedback.
Implementation Method 1
an oscillator comprising a hysteretic comparator and a loop filter configured to output an oscillation signal
Data Source
AI summary
This application relates to sensing circuits for sensing a physical property or quantity of interest. The sensing circuit has an oscillator comprising a hysteretic comparator and a loop filter configured to output an oscillation signal. The loop filter comprises a first component with an electrical property that varies with the physical property or quantity of interest. A time constant of the loop filter depends on the electrical property of the first component. A decoder is configured to receive the oscillation signal and provide an indication of any change in frequency of the oscillation signal as an indication of a change in the physical property or quantity of interest. The electrical property may be an impedance, such as a resistance.