External Connector Corrosion Mitigation via Dynamic Voltage Control
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Solution Overview
Problem
Portable electronic devices face challenges in detecting and mitigating short circuits caused by liquid exposure at their external connectors, which can lead to corrosion, and existing methods may not effectively differentiate between liquid and solid contaminants.
Innovation Solution
A method is implemented in electronic systems where the voltage of a pin is compared to a threshold, and if exceeded, the power supply voltage is reduced to mitigate corrosion, with a resistor switch circuit pulling the pin to ground during measurement, allowing for continuous power and communication through the connector at reduced performance levels, and context awareness modules trigger the detection process based on accessory type, location, and user activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply voltage is reduced to mitigate corrosion on connector pins, then the corrosion resistance is improved, but the power transfer and communication performance deteriorates
Solution Approach 1:
The power supply voltage to the connector pins is made dynamically adjustable rather than fixed. The system can reduce the voltage to mitigation levels (e.g., from 5V to 1V or lower) when liquid detection is active, and restore full power when no liquid is detected, allowing the connector to adapt its power level based on environmental conditions
Solution Approach 2:
The voltage parameter of the power supply is changed from a constant value to a variable value that can be adjusted between different levels. The system transitions the voltage parameter between a normal operating level (e.g., 5V) and a mitigation level (e.g., 1V or lower) based on the detected presence of liquid, thereby optimizing both corrosion protection and power transfer performance at different times
2Reliability
If continuous monitoring of pin voltage is performed to detect liquid intrusion, then the detection reliability is improved, but the energy consumption increases
Solution Approach 1:
Instead of continuous monitoring, the system performs periodic voltage measurements at scheduled intervals (e.g., every few seconds or minutes). The microcontroller enters low-power sleep modes between measurement cycles, significantly reducing energy consumption while maintaining adequate detection capability for liquid intrusion events
Solution Approach 2:
The system leverages existing operational contexts (such as when the device is already awake for other reasons, or when communication sessions are active) to perform voltage measurements without requiring dedicated high-power monitoring periods. The measurement operations are integrated into existing system wake states, reducing additional energy overhead
3Measurement precision
If the voltage threshold for liquid detection is set low to improve sensitivity, then the detection precision for liquid is improved, but the false detection of solid contaminants increases
Solution Approach 1:
The system incorporates feedback mechanisms where detection results from multiple measurements and multiple sensors (if available) are analyzed collectively. The microcontroller evaluates patterns in the voltage readings over time and across different pins, using decision algorithms that distinguish between the electrical characteristics of liquid bridges (which typically show specific resistance patterns) and solid contaminants, thereby reducing false detections while maintaining sensitivity
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 detects liquid intrusion and reduces corrosion risk at external connectors of portable devices, allowing for continued operation with reduced performance while minimizing damage from liquid exposure, and differentiates between liquid and solid contaminants based on voltage and user activity.
Implementation Method 1
The first pin is un-driven except for being pulled to ground through a predetermined first resistance... in response to having detected the presence of short-circuit causing moisture adjacent to the port or within the port
Data Source
AI summary
A voltage of a first pin that is one of several pins of an external connector of a system is measured, while the first pin is un-driven except for being pulled to ground through a first resistance, and a second pin of the external connector is being used as a power supply rail of the system. The measured voltage is compared to a short circuit threshold and in response to that threshold being exceeded, the power supply voltage on the second pin is reduced. In such an embodiment, no test stimulus needs to be applied to any of the pins of the external connector. Other embodiments are also described and claimed.