USB Type-C Receptacle Liquid Detection and Corrosion Protection
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Solution Overview
Problem
USB Type-C receptacles are prone to electrochemical corrosion when exposed to conductive liquids due to the periodic pulse signals used for handshaking, which can lead to corrosion of the pins over time.
Innovation Solution
A USB Type-C receptacle design that outputs a lower average power level detection signal on the ground terminal, decoupled from the ground plane, to detect the presence of a mating plug, reducing the duration and voltage of the signal to minimize corrosion risk, and includes a voltage divider to sense the presence of conductive liquids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic pulse signals are output on the CC terminal pin for handshaking, then detection of plug insertion and device communication can be initiated, but electrochemical corrosion occurs on the pins when conductive liquid is present in the receptacle
Solution Approach 1:
The patent introduces an intermediary detection signal transmitted through the ground terminal that mediates between the need for plug detection and the harm caused by high-power signals in liquid environments. This intermediary signal enables indirect detection of plug presence without directly exposing the CC terminal to high-power periodic pulses when liquid is present, thus resolving the contradiction between reliable plug detection and corrosion prevention
Solution Approach 2:
The patent changes the parameters of the detection signal by transmitting it through the ground terminal rather than the CC terminal, and by using different signal characteristics (continuous vs. periodic pulses). This parameter change allows the system to detect plug insertion while minimizing the electrochemical corrosion effect that occurs when high-power periodic signals are applied to pins in the presence of conductive liquid
2Object-affected harmful factors
If a water tight cap is provided over the receptacle to prevent liquid intrusion, then corrosion is prevented, but the cap is inconvenient to remove and replace and can get lost
Solution Approach 1:
The patent enables the receptacle to self-detect the presence of conductive liquid through voltage sensing on the ground terminal and automatically respond by disabling or reducing the power of handshaking signals. This self-service capability eliminates the need for external protective caps while maintaining corrosion prevention, as the system autonomously protects itself from liquid-induced corrosion without requiring user intervention to cap or unc cap the receptacle
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 significantly reduces the risk of electrochemical corrosion by minimizing the power of the handshaking signal and allows for the detection of liquids, preventing damage to the receptacle and ensuring reliable device operation.
Implementation Method 1
a voltage divider to sense the presence of conductive liquids
Implementation Method 2
the aforementioned periodic pulse sent out on the CC terminal pin can drive an electrochemical corrosion reaction on pins of the receptacle
Data Source
Figure 1~2
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AI summary
A device is equipped with an electrical connector in the form of a receptacle that is subject to liquid intrusion. The device detects the insertion of a mating connector and optionally detects the presence of liquid in the receptacle by applying a low power, pulsed sense signal to a terminal pin of the receptacle while the terminal pin is decoupled from a circuit part to which the terminal pin is normally coupled and concurrently sensing a voltage coupled from the terminal pin and comparing the voltage to at least a predetermined lower voltage bound and optionally a predetermined upper voltage bound and based on the results of those comparison deduces the presence of a mating connector or optionally the presence of liquid in the receptacle.