Low Power Wakeup Detection Circuit for Portable Devices
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Solution Overview
Problem
Portable electronic devices with touch-sensitive displays consume significant power due to periodic scanning required to detect touch events, leading to reduced battery life.
Innovation Solution
A low power wakeup detection circuit that uses force sensing transducers and a comparator to detect touch events without periodic scanning of the touch-sensitive display, switching to full power mode only when a predefined force threshold is exceeded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic scanning is used to detect touch events on the touch-sensitive display, then touch event detection capability is improved, but power consumption increases
Solution Approach 1:
The patent implements periodic scanning only during active periods when the device is awake, rather than continuous scanning. The controller activates the touch-sensitive display and performs scanning during defined active periods, then enters a low-power sleep mode during inactive periods, eliminating unnecessary continuous power consumption while maintaining touch detection capability when needed
Solution Approach 2:
The system performs preliminary actions by activating the touch-sensitive display and establishing scanning capability before touch events need to be detected. The controller proactively manages power states, switching to active mode in advance when touch detection may be needed, rather than maintaining constant scanning readiness
2Speed
If continuous monitoring of the touch-sensitive display is implemented, then response time to touch events is improved, but battery life is reduced
Solution Approach 1:
The system alternates between active scanning periods and sleep periods, achieving fast response during active states while conserving battery during inactive states. The controller manages periodic activation of the touch-sensitive display and scanning operations, ensuring rapid response capability is available when needed without continuous power drain
Solution Approach 2:
The system dynamically adjusts its operational state between active and sleep modes based on whether touch detection is currently needed. The controller can quickly transition from sleep mode to active scanning mode, providing dynamic response capability that adapts to actual usage conditions rather than maintaining a fixed continuous monitoring state
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
Significantly reduces power consumption by eliminating unnecessary scanning, thereby extending battery life and improving device efficiency during idle periods.
Implementation Method 1
a plurality of force sensing transducers for measuring force data
Implementation Method 2
a comparator for comparing the summed force data from the multi-port switch to a wakeup force threshold; wherein the controller is configured to wake from a sleep mode and return to a full power mode when the summed force data is greater than the wakeup force threshold
Data Source
AI summary
The present disclosure provides a low power wakeup detection circuit and a portable electronic device having a low power wakeup detection circuit. In accordance with one embodiment, there is provided a portable electronic device, comprising: a housing; a controller received within the housing; a touch-sensitive display having a touch-sensitive overlay, the touch-sensitive display being mechanically constrained by the housing; at least one force sensing transducer located below the touch-sensitive display on an opposite side to the touch-sensitive overlay, the at least one force sensing transducer being connected to the controller and measuring forces applied to the touch-sensitive display; wherein the controller is configured for: initiating a sleep mode from a full power mode in response to a trigger; when in the sleep mode, reading force data measured by the at least one force sensing transducer at a reduced duty cycle relative to the full power mode, comparing the force data to a wakeup force threshold, and returning to the full power mode from the sleep mode when the force data is greater than the wakeup force threshold.