Object Detection Circuit Using Small Signal Generator
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Solution Overview
Problem
Conventional object detection systems in wireless charging systems have limited sensitivity, especially in detecting high-resonant-frequency foreign objects and human bodies, and consume high power, leading to inefficiencies and potential overheating issues.
Innovation Solution
The system employs a dual-coil configuration with a digital synthesizer and resistive digital-to-analog converters to generate small signals across a wide frequency range, allowing for sensitive detection without activating the main transmit/receive inverter, thus reducing power consumption and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the main transmit inverter circuit is activated to provide power signals to the coil for object detection, then the detection capability is improved, but the power consumption increases and overheating issues occur
Solution Approach 1:
The patent divides the detection function into two separate circuits: a main transmit inverter circuit for power transmission and a small signal generator circuit for detection. This segmentation allows the detection function to be performed independently with minimal power consumption, resolving the contradiction between detection sensitivity and power consumption.
Solution Approach 2:
Instead of using the full power of the main transmit inverter for detection, the patent applies partial action by using a small signal generator that provides just enough signal strength for effective detection. This partial action achieves the detection goal while avoiding excessive power consumption and overheating.
2Measurement precision
If the main transmit inverter circuit is activated for object detection, then detection capability is improved, but the system complexity increases
Solution Approach 1:
The patent segments the detection function from the power transmission function by introducing a dedicated small signal generator circuit. This separate circuit is specifically designed for detection purposes, simplifying the overall system architecture by assigning specific functions to specific components rather than using the main transmit inverter for both purposes.
3Measurement precision
If conventional detection methods are used, then the system is simple to operate, but the detection sensitivity for high-resonant-frequency objects is limited
Solution Approach 1:
The patent changes the frequency parameter of the detection signal by using a small signal generator that can operate across a wide frequency range. This allows the system to detect high-resonant-frequency objects that conventional low-frequency detection methods cannot detect, improving detection sensitivity without requiring complex additional hardware.
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 enhances detection sensitivity, reduces power consumption, and prevents overheating by accurately identifying and differentiating between 'friend' and foreign objects, including high-resonant-frequency objects and human bodies, within a wider frequency range.
Implementation Method 1
The wireless power transmitter unit uses power inverter circuits to execute a few pings to excite a coil of the wireless charging system and measure a response from the coil
Implementation Method 2
one or more circuits are further configured to measure a coupling coefficient between the one or more objects and the coil according to the comparison
Data Source
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AI summary
Systems and methods for object detection are provided. The system includes at least a coil, a main transmit inverter circuit, and one or more circuits. The one or more circuits are configured to generate a small signal, provide the small signal to the coil, receive a response signal, compare the response signal with one or more reference signals, and detect an object according to the comparison. The object is detected without providing a signal from the main transmit/receive inverter circuit to the coil.