Shut-off Circuit for Liquid Detection in Portable Devices
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Solution Overview
Problem
Portable devices, such as cellular telephones, are prone to damage from liquid exposure due to the formation of short-circuits, which can occur when liquids create unintended paths of low resistance across the circuit, exceeding the power handling capacity of components and leading to overheating and non-operational circuits.
Innovation Solution
A shut-off circuit is implemented in portable devices that detects the presence of liquids using sensors adjacent to ports and interrupts power flow to the system circuit, preventing short-circuits and potential damage by disconnecting power when liquids are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power flow is continuously maintained in portable devices, then operational functionality is preserved, but vulnerability to liquid-induced short-circuits increases
Solution Approach 1:
The shut-off circuit is configured to interrupt power flow before liquid damage can occur. Liquid sensors detect liquid presence in advance, and the control circuit preemptively cuts power through the shut-off circuit, preventing short-circuits before they can damage components. This preliminary action resolves the contradiction by maintaining reliability while reducing vulnerability through proactive protection.
Solution Approach 2:
The shut-off circuit acts as an intermediary between the power source and the system circuit. It mediates power flow by selectively connecting or disconnecting based on liquid sensor inputs. This intermediary mechanism allows the system to maintain operational functionality when safe while blocking harmful power flow when liquid is detected, thus resolving the contradiction between continuous operation and liquid damage prevention.
2Reliability
If liquid sensors are added to detect liquid presence, then protection capability is improved, but device complexity increases
Solution Approach 1:
The control circuit is designed to perform multiple functions: it processes signals from liquid sensors, controls the shut-off circuit, and can potentially integrate with other device management functions. By making the control circuit multi-functional, the patent reduces the need for separate dedicated circuits for each function, thereby improving liquid damage protection while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent combines the liquid sensor detection function, the control logic, and the shut-off mechanism into an integrated protection system. Rather than adding completely separate systems, the liquid sensors are integrated with the existing power management infrastructure, and the shut-off circuit is merged with the power distribution network. This merging approach improves protection capability while limiting the increase in device complexity.
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
The shut-off circuit effectively protects the device from liquid-induced damage by preventing power flow through short-circuits, thereby safeguarding electronic components and maintaining the device's operational integrity.
Implementation Method 1
liquids, such as water, have less resistance than the desired path for the power through the circuit. Liquids on the surface of the circuit can create unintended paths across the circuit with little resistance.
Data Source
AI summary
A shut-off circuit interrupts the flow of power to the system circuit of a portable device, when liquids are detected within the portable device. Liquid sensors are placed proximate to the ports of the portable device. The ports may admit the flow of liquids, so the liquid sensors may detect the passage of liquids into the portable device. If the liquid sensors detect liquids entering the portable device, a shut-off circuit interrupts the flow of power from the battery to the system circuit.