USB-C Cable Thermal Protection via Configuration Channel
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Solution Overview
Problem
Modern USB-C cables face challenges in thermal protection due to the impractical size and cost of positive temperature coefficient (PTC) elements required to handle high power levels, such as 100 watts, which are necessary to prevent overheating and thermal damage.
Innovation Solution
Implementing PTC elements on non-power conductors, such as the configuration channel conductor (CC conductor) and Vconn conductor, which increase resistance at elevated temperatures to prevent current flow, allowing devices to detect faults and reduce power transmission, thereby mitigating thermal damage without the need for large and expensive PTC elements on power conductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PTC elements are installed on power conductors to protect against overheating, then thermal protection is improved, but the size and cost of the cable increase prohibitively
Solution Approach 1:
The patent uses non-power conductors (data conductors or configuration channel conductors) as intermediary elements to provide thermal protection. These conductors carry minimal current and serve as sensors for temperature detection. When overheating is detected, the PTC element on these intermediary conductors increases resistance, signaling the devices to reduce or stop power transmission, thereby providing thermal protection without requiring large PTC elements on the power conductors themselves.
2Reliability
If PTC elements are used to handle 100 watts of power, then thermal protection capability is improved, but the PTC element becomes prohibitively large and expensive
Solution Approach 1:
The patent segments the thermal protection function from the power transmission function. Instead of placing a single large PTC element on the power conductor to handle 100 watts, the system uses small PTC elements on non-power conductors (which carry only nominal currents) to detect thermal conditions. The actual power control is then managed by the connected devices based on resistance changes detected on these smaller conductors, effectively segmenting the protection mechanism into sensing and control components.
3Device complexity
If PTC elements are placed on non-power conductors, then cable cost and size are reduced, but the ability to directly protect power conductors is weakened
Solution Approach 1:
The patent implements a feedback mechanism where PTC elements on non-power conductors monitor thermal conditions and provide resistance change feedback to the connected devices. When the PTC element heats up due to ambient temperature or nearby power conductor overheating, its resistance increases, which is detected by the devices. This feedback triggers the devices to reduce or stop power transmission, indirectly protecting the power conductors without direct intervention on those conductors.
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 solution provides effective thermal protection for USB-C cables by allowing devices to detect and respond to overheating conditions, preventing thermal damage while maintaining a compact and cost-effective design, as the PTC elements only need to handle nominal currents on non-power conductors.
Implementation Method 1
the PTC element has a resistance that increases as the temperature of the PTC element increases
Implementation Method 2
a first protection circuit coupled to the first data conductor and associated with a first temperature sensing element
Data Source
AI summary
A cable including a power conductor configured to transmit electrical power between a first device and a second device, a first data conductor configured to transmit data between the first device and the second device, and a first protection circuit coupled to the first data conductor and associated with a first temperature sensing element, the first protection circuit configured to mitigate current flowing through the first data conductor if a temperature detected by the first temperature sensing element rises above a predefined first trip temperature, wherein the opening of the first data line indicates a fault condition to a device to which the cable is connected, whereby electrical power flowing through the power conductor is resultantly mitigated.