Wireless Charging Scheduling to Reduce SAR Exposure
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Solution Overview
Problem
The integration of multiple wireless communication systems in information handling systems, including charging coils, often leads to increased electromagnetic radiation absorption rates (SAR) that exceed regulatory limits, necessitating power reduction and additional hardware placement, which complicates design and increases costs.
Innovation Solution
A wireless charging scheduling system that coordinates with an antenna controller to initiate charging only when antennas are not transmitting, using a processor, memory, and power management unit to schedule charging processes, thereby reducing SAR levels by avoiding overlap with data transmission times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple wireless communication systems including charging coils are integrated in information handling systems, then device functionality and wireless charging capability are improved, but electromagnetic radiation absorption rates (SAR) increase and exceed regulatory limits
Solution Approach 1:
The system proactively checks antenna transmission status before initiating wireless charging. The controller determines whether antennas are currently transmitting data, and only initiates charging when antennas are in receiving mode or idle, preventing harmful electromagnetic radiation overlap before it occurs.
Solution Approach 2:
The wireless charging system dynamically adjusts its operation based on real-time antenna status. The controller continuously monitors antenna transmission states and adapts charging initiation accordingly, making the system flexible and responsive to changing electromagnetic conditions rather than operating statically.
2Object-affected harmful factors
If power reduction is implemented to comply with SAR limits, then electromagnetic radiation emission is reduced, but wireless charging efficiency and power transfer rate decrease
Solution Approach 1:
The system uses periodic time-slot allocation where wireless charging operates during specific time periods when antennas are not transmitting. This periodic scheduling allows full power charging during designated charging slots while maintaining regulatory compliance during data transmission periods, achieving both SAR compliance and charging efficiency.
3Object-affected harmful factors
If additional hardware placement is implemented to manage SAR levels, then electromagnetic radiation compliance is improved, but device complexity and design difficulty increase
Solution Approach 1:
The existing antenna controller is made multi-functional by adding SAR management capabilities. The same controller that manages antenna operations also determines transmission status and controls wireless charging initiation, eliminating the need for separate dedicated SAR management hardware and reducing overall device complexity.
4Productivity
If wireless charging operates concurrently with antenna transmission, then charging speed is improved, but SAR levels exceed regulatory limits creating harmful exposure
Solution Approach 1:
The system implements a feedback mechanism where the antenna controller provides real-time transmission status information to the wireless charging controller. Based on this feedback, the charging controller makes informed decisions about whether to initiate or delay charging, ensuring SAR compliance while maximizing charging speed when conditions permit.
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 effectively reduces SAR levels, allowing for compliant electromagnetic radiation emission while maintaining device functionality and reducing costs by optimizing power usage and hardware placement.
Implementation Method 1
a charging coil to charge a battery in the information handling system or an input/output device of the information handling system via inductive charging
Data Source
AI summary
An information handling system with a wireless charging device may include a processor; a memory; a power management unit (PMU); an antenna controller to provide instructions to a radio to cause an antenna to transceive wirelessly with a network; a wireless charging scheduling controller configured to: receive transmission scheduling data from the antenna controller descriptive of when the radio is transmitting and receiving data to and from the network; and initiate, at a charging coil of the wireless charging device, a charging procedure to wirelessly charge a power storage device when the transmission scheduling data indicates that the radio is receiving data from the network or is idle.