Inductive Power Supply Q Factor Object Detection
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Solution Overview
Problem
Existing wireless charging devices consume significant power due to continuous scanning for object presence, which can be reduced by using an analog circuit to monitor the Quality Factor (Q Factor) of a resonant circuit to detect objects, allowing the high-power digital communication processor to remain idle until an object is detected.
Innovation Solution
An inductive power supply system with a resonant circuit that changes its Q Factor based on object presence, using a driver circuit to send different power levels and an object detector to switch between charge and detect states, and a controller to ping the resonant circuit to sample amplitude peaks, distinguishing between object present and absent states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous scanning for object presence is performed, then object detection reliability is improved, but power consumption increases
Solution Approach 1:
The system performs periodic scanning of the resonant circuit Q Factor instead of continuous scanning. The controller periodically activates the resonant circuit and measures its Q Factor to detect object presence, allowing the high-power digital communication processor to remain idle between scans. This periodic operation maintains detection reliability while significantly reducing average power consumption.
Solution Approach 2:
The patent introduces an intermediary detection mechanism using the resonant circuit's Q Factor as a mediator to detect object presence. Instead of directly using high-power digital communication processing for continuous detection, the system uses the Q Factor of the resonant circuit as an intermediate indicator that changes in response to object presence, enabling low-power detection while maintaining reliability.
2Speed
If high-power digital communication processor remains active, then communication responsiveness is improved, but overall power usage increases
Solution Approach 1:
The system performs preliminary detection using the low-power Q Factor measurement before activating the high-power digital communication processor. By first scanning the resonant circuit and detecting object presence through Q Factor changes, the system can prepare and then activate communication processing only when needed, maintaining responsiveness while reducing overall power consumption.
Solution Approach 2:
The system dynamically adjusts the operational state of the digital communication processor based on detection results. The processor transitions between idle and active states depending on whether an object is detected through Q Factor measurement. This dynamic operation maintains communication responsiveness when objects are present while minimizing power consumption during idle periods.
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 approach reduces power consumption by only activating the high-power digital communication processor when an object is detected, maintaining a quiescent state otherwise, thereby lowering overall power usage.
Implementation Method 1
an inductive coupler including a resonant circuit having a first resonant state in response to an object at a first distance from the inductive power supply, and a second resonant state in response to the object at a second distance from the inductive power supply
Implementation Method 2
an inductive coupler including an LC tank circuit having a first Q-Factor in response to an object at a first distance from the wireless power transmitter, and a second Q-Factor in response to an object at a second distance from the wireless power transmitter
Data Source
AI summary
One example discloses an inductive power supply device, comprises: an inductive coupler including a resonant circuit having a first resonant state in response to an object at a first distance from the inductive power supply, and a second resonant state in response to the object at a second distance from the inductive power supply; a driver circuit coupled to send a first power-level to the inductive coupler when in a charge-object state and to send a second power-level to the inductive coupler when in a detect-object state, wherein the second power-level is less than the first power-level; and an object detector coupled to detect the first and second resonant states and place the driver circuit in the charge-object state in response to the first resonant state, and place the driver circuit in the detect-object state in response to the second resonant state.