USB Cable Quality Detection via Voltage Drop Monitoring
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Solution Overview
Problem
USB cables, including those with USB Power Delivery capabilities, may become defective due to field stress or poor quality control, leading to safety risks as they struggle to handle increased currents, causing overheating and potential catastrophic failures.
Innovation Solution
A method and system that monitor the rate of change of voltage across a USB cable to detect overheating, allowing for the reduction of power delivery to prevent damage, without the need for direct temperature sensors, by adjusting the current and voltage to ensure safe operation within USB standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If USB Power Delivery cables are used to deliver up to 100W of power at 20V with currents up to 5A, then faster charging times are achieved, but the cables may become defective during use due to field stress and overheating
Solution Approach 1:
The system performs preliminary actions by measuring the voltage drop across the cable before full power delivery begins. This allows the system to assess cable quality and predict potential overheating issues before they occur, enabling preventive power reduction if the cable is deemed unsuitable for high-current operation.
Solution Approach 2:
The system implements continuous feedback by monitoring the voltage drop across the cable during power delivery. Based on the measured voltage drop and calculated cable resistance, the system dynamically adjusts the power delivery level to prevent cable overheating and failure, thereby maintaining reliable operation under varying cable conditions.
2Loss of time
If higher currents are supplied through USB cables to reduce charging time, then charging speed increases, but the cables may overheat and pose safety risks
Solution Approach 1:
The system performs preliminary assessment of cable suitability by measuring voltage drop before initiating high-current charging. This preliminary action identifies cables that would overheat under high current, allowing the system to prevent harmful heating before it occurs by limiting power delivery to safe levels.
Solution Approach 2:
The system converts the potentially harmful voltage drop (which indicates cable resistance and potential overheating) into a useful measurement. By monitoring voltage drop, the system gains information about cable condition and uses this to prevent overheating, transforming a harmful effect into a protective mechanism.
3Reliability
If voltage drop across the cable is used to determine cable quality, then cable safety can be monitored, but additional measurement circuitry and control logic are required
Solution Approach 1:
The system achieves cable safety monitoring using existing power delivery measurement circuitry that is already present in USB Power Delivery implementations. The same voltage and current measurement circuits used for power management are repurposed to measure voltage drop and assess cable quality, eliminating the need for separate dedicated measurement hardware.
Solution Approach 2:
The system performs self-assessment of cable quality using its own internal measurement capabilities. By utilizing its existing voltage and current sensing circuits, the system can independently evaluate cable condition and adjust power delivery accordingly, without requiring external monitoring devices or additional complex control systems.
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 mitigates the risk of cable failure and ensures safe power delivery by continuously monitoring voltage changes, reducing the risk of overheating and maintaining compliance with USB standards, thereby enhancing user safety and preventing catastrophic failures.
Implementation Method 1
the resistance through a power delivery cable... increases with an increase in temperature
Implementation Method 2
the cables may become defective during use due to field stress... The large power supplied through a defective USB can pose a significant safety risk
Data Source
AI summary
In one embodiment, a method includes receiving power at a power consumer device coupled to a power provider device by a cable. The received power is supplied at a first current at an input of the power consumer device and is supplied to a load in the power consumer device. The method includes measuring a rate of change of the voltage at the input of the power consumer device, and determining whether the rate of change of the voltage at the input of the power consumer device is less than a first target rate of change of voltage. The current received at the input of the power consumer device is reduced to a second current lower than the first current if the rate of change of the voltage at the input of the power consumer device is greater than the first target rate of change of voltage.