Wireless Charging Transmitter Ping Signal Detection
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Solution Overview
Problem
Existing wireless charging systems face issues with large currents being generated during analog and digital ping signals when metal objects are present, leading to potential damage or noise, as current protection systems are ineffective for short analog ping signals.
Innovation Solution
A method and apparatus utilizing a bridge circuit to generate ping signals with varying parameters such as frequency, duty cycle, and phase shift angle, which are monitored to determine the presence of an eligible object, preventing excessive current by adjusting the signal parameters over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional over current protection system is used, then the transmitter is protected from damage, but the protection does not take effect for short analog ping signals and large currents are still generated
Solution Approach 1:
The patent applies preliminary action by performing object detection and current monitoring before the analog ping signal causes harmful large currents. The system continuously monitors current during the brief analog ping signal window and takes preventive action before excessive current can damage the transmitter, thus resolving the contradiction between maintaining transmitter protection and preventing large current generation during short detection signals
2Reliability
If the analog ping signal duration is extended to allow over current protection to take effect, then protection becomes effective, but the detection time is increased and charging efficiency is reduced
Solution Approach 1:
The patent applies continuity of useful action by implementing continuous current monitoring throughout the analog ping signal duration. This allows the system to maintain effective protection without extending the signal duration, as the monitoring is ongoing and immediate rather than requiring a prolonged signal window, thus preventing both time loss and ensuring protection effectiveness
3Object-generated harmful factors
If the transmitter continuously monitors current to detect metal objects, then large currents are prevented, but energy consumption increases
Solution Approach 1:
The patent applies periodic action by implementing current monitoring at specific intervals and during critical phases of the wireless charging operation, particularly during analog ping signal transmission. This periodic monitoring approach prevents large currents from metal objects while consuming less energy than continuous monitoring, as the system only activates monitoring when objects are likely to be present and when the risk of large current generation is highest
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 prevents large currents from being generated, reducing the risk of damage or noise, while maintaining energy efficiency by varying the ping signal parameters, especially when large metal objects are detected in the charging area.
Implementation Method 1
Induction based wireless charging has become a very popular feature for consumer electronic devices. An induction based wireless charging system typically includes a transmitter (Tx) that provides charging power.
Implementation Method 2
If the metal object is large enough in size, the transmitted analog/digital ping signal may result in a large current at the transmitter.
Data Source
AI summary
A method for detecting objects in a charging area of a wireless charging transmitter includes providing a bridge circuit that generates a ping signal, and providing the ping signal to a transmitter terminal. The method further includes monitoring at least one of a current of a power supply connected to the bridge circuit, and a current at the transmitter terminal to determine if an eligible object is in the charging area. The ping signal has parameters including frequency, duty cycle, and phase shift angle, where at least one of these parameters varies with time.