Force Sensing Transducer Wake-Up 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 and increased power consumption.
Innovation Solution
A low power wakeup detection circuit that uses a force sensing transducer beneath the touch-sensitive display to detect forces greater than a predetermined wake force threshold, allowing the device to wake up only when a valid touch event is detected, thereby reducing unnecessary scanning and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic scanning is used to detect touch events on the touch-sensitive display, then touch events can be detected reliably, but power consumption increases significantly
Solution Approach 1:
The patent applies periodic action by using motion sensor circuits to detect device movement and trigger wake-up events selectively, rather than continuously scanning the touch display. The system periodically checks for motion events and only activates full touch scanning when motion is detected, thereby reducing overall power consumption while maintaining reliable touch event detection when needed
Solution Approach 2:
The patent implements preliminary action by using motion sensors to detect device movement before the touch display scanning is activated. This preliminary motion detection allows the system to prepare for potential touch events by waking up the display scanning circuits only when motion is detected, rather than maintaining continuous scanning, thus reducing power consumption while ensuring touch events are not missed
2Ease of operation
If the touch-sensitive display is kept active to detect touch events, then user interaction is responsive, but battery life is reduced
Solution Approach 1:
The system uses periodic motion detection to trigger display activation. The motion sensor circuits continuously monitor for device movement at low power, and only when motion is detected does the system activate the full touch-sensitive display scanning. This periodic triggering mechanism maintains user interaction responsiveness when the device is in use while extending battery life during stationary periods
Solution Approach 2:
The motion sensor circuits serve themselves by continuously monitoring device movement without requiring full display activation. The system automatically determines when touch scanning should be activated based on motion detection, eliminating the need for continuous user presence or manual wake-up actions, thus maintaining responsiveness while conserving battery power
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 significantly reduces power consumption by eliminating the need for periodic scanning, extending battery life while maintaining the ability to detect touch events and providing tactile feedback, thus improving the efficiency of portable electronic devices.
Implementation Method 1
a force sensing transducer beneath the touch-sensitive display to detect forces
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
The present disclosure provides a method of waking a portable electronic device and a portable electronic device configured to perform the same. In accordance with one embodiment, there is provided a method of conserving power on a portable electronic device, the portable electronic device having a device housing which comprises a touch-sensitive display, an accelerometer, and a force sensing transducer, the method comprising: causing the portable electronic device to enter a sleep mode in response to a trigger condition, wherein the touch-sensitive display is deactivated in the sleep mode and the force sensing transducer measures forces applied to the touch-sensitive display at a reduced rate relative to a rate of a full power mode when in the sleep mode; detecting an inertial event using the accelerometer; causing the force sensing transducer to measure forces applied to the touch-sensitive display at the rate of the full power mode in response to detection of an inertial event; detecting forces applied to the touch-sensitive display using the force sensing transducer at the rate of the full power mode; causing the touch-sensitive display to be reactivated in response to detection of a force which is greater than a predetermined wake force threshold; detecting touch events on the touch-sensitive display; and causing the portable electronic device to wake from the sleep mode in response to detection of a touch event within a first predetermined duration of the detection of the force which is greater than a predetermined wake force threshold.