Wireless Charging Presence Detection Using Ambient Light Sensors
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Solution Overview
Problem
Wireless charging systems often waste power by remaining in standby mode and continuously emitting detection signals when not in use, consuming energy unnecessarily.
Innovation Solution
A low-power presence sensing device using photosensors to detect the presence of a portable electronic device by sensing ambient light differences, allowing the wireless charging circuit to turn off when not in use, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wireless charging systems continuously emit detection signals to detect portable electronic devices, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The system uses periodic ambient light sensing instead of continuous detection signal emission. The photosensors periodically monitor ambient light levels to detect device presence, replacing the continuous electromagnetic detection signals with intermittent optical measurements, thereby reducing power consumption while maintaining detection capability
Solution Approach 2:
The patent substitutes electromagnetic detection signals with optical detection using photosensors. Instead of emitting and detecting electromagnetic fields for device presence detection, the system uses photosensors to detect changes in ambient light caused by the physical presence of a portable electronic device, achieving detection with minimal power consumption
2Speed
If wireless charging systems remain in standby mode to detect devices quickly, then response speed is improved, but power consumption increases
Solution Approach 1:
The system performs preliminary detection using photosensors that continuously or periodically monitor ambient light levels without consuming significant power. This preliminary optical detection prepares the system to quickly activate full wireless charging detection and operation when a device is detected, achieving fast response without sustained high power consumption
Solution Approach 2:
The system dynamically adjusts its detection mode based on ambient light sensor readings. When no device is present, the system operates in low-power standby mode using only photosensors. When a device is detected through light occlusion, the system dynamically transitions to active wireless charging mode, optimizing both response speed and power consumption
3Measurement precision
If active-type systems with light sources and sensors are used to detect device presence, then detection precision is improved, but power consumption increases
Solution Approach 1:
The patent extracts and removes the active light source component from the detection system. Instead of using an integrated light source that emits light for reflection detection, the system relies solely on ambient light sources already present in the environment, eliminating the power consumption associated with active illumination while maintaining detection precision through photosensor-based ambient light monitoring
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 significantly reduces power consumption by eliminating the need for continuous detection signal emission, achieving power savings of an order of magnitude lower than active-type systems, while maintaining effective detection of portable electronic devices.
Implementation Method 1
A first photosensor positioned inside the effective charging range of the wireless charging circuit outputs a first signal representative of an intensity of ambient light incident on the first photosensor
Data Source
AI summary
An example device includes a wireless charging circuit to wirelessly charge a portable electronic device. The device further includes a first photosensor positioned within an effective charging range of the wireless charging circuit, the first photosensor to output a first signal, and a second photosensor positioned outside the effective charging range, the second photosensor to output a second signal. The device further includes a control circuit connected to the wireless charging circuit, the first photosensor, and the second photosensor. The control circuit detects the portable electronic device positioned within the effective charging range of the wireless charging circuit by detecting a difference between the first signal and the second signal. The control circuit turns on the wireless charging circuit in response to detecting the difference. The control circuit turns off the wireless charging circuit in response to detecting that the first signal matches the second signal.