Terminal Charging Current Adjustment Using Cable Impedance
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Solution Overview
Problem
Charging issues arise when using non-original adapters or low-quality USB cables, leading to overcurrent protection, slow charging, or failure to charge due to mismatched power characteristics and impedance problems, which can result in unsafe heat generation.
Innovation Solution
A method and terminal that detect the voltage and current of a charging apparatus, calculate the cable impedance, and adjust the charging current to ensure compatibility, using formulas like R = (V1 - V2)/I2 for impedance calculation and V = Vadapter - I4 × R for output voltage adjustment, to determine a suitable charging current that prevents overcurrent and ensures stable charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a non-original adapter is used for charging, then charging cost is reduced and compatibility is improved, but overcurrent protection is triggered and charging cannot be performed
Solution Approach 1:
The terminal dynamically adjusts charging parameters (current, voltage) based on detected cable impedance characteristics. By measuring voltage at different current levels and calculating impedance, the system adapts to non-original adapters by modifying charging parameters to match the adapter's capabilities, preventing overcurrent protection while maintaining charging functionality.
2Adaptability or versatility
If a USB cable of relatively poor quality is used, then charging cost is reduced, but voltage is excessively shunted to the cable and charging is slow or cannot be performed
Solution Approach 1:
The system detects cable impedance by measuring voltage drops at different current levels. Based on the calculated impedance value, the terminal adjusts charging current and voltage parameters in real-time. For cables with higher impedance (poorer quality), the system reduces current and adjusts voltage to compensate for voltage shunt, maintaining acceptable charging speed while ensuring compatibility with lower-quality cables.
3Adaptability or versatility
If a USB cable of relatively poor quality is used, then charging cost is reduced, but impedance problem causes voltage reaching terminal to be excessively low
Solution Approach 1:
The terminal implements a feedback mechanism by continuously monitoring voltage at the charging port during charging. Based on the detected voltage and current values, the system calculates cable impedance and uses this information to adjust charging parameters. This closed-loop control ensures that despite variations in cable quality, the terminal receives stable and adequate voltage for reliable charging.
4Reliability
If original chargers are used, then charging reliability is ensured, but device complexity increases due to multiple chargers needed for different phones
Solution Approach 1:
The terminal implements a universal charging detection and adaptation mechanism that works with various adapter types (original and non-original). By automatically detecting cable impedance characteristics and adjusting charging parameters accordingly, the system enables a single charger to reliably charge different terminal models and configurations, reducing the need for multiple specialized chargers while maintaining charging reliability.
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 allows the terminal to adapt to different charging apparatuses, improving charging efficiency and safety by preventing overcurrent and ensuring stable output voltage, thus enhancing the user's charging experience.
Implementation Method 1
calculating a cable impedance of the charging cable according to the first voltage value, the second charging current, and the second voltage value; R = (V1 - V2)/I2
Implementation Method 2
calculating an output voltage value of the charging apparatus according to a rated voltage value of the charging apparatus, the fourth charging current and the cable impedance of the charging cable; V = Vadapter - I4 × R
Data Source
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AI summary
A charging method, a charging apparatus, and a terminal are disclosed. The method includes: identifying, when it is detected that a charging apparatus is inserted into a charging port of a terminal by using a charging cable, a first voltage value of the charging port; setting a second charging current; identifying a second voltage value of the charging port at the second charging current; calculating a cable impedance of the charging cable according to the first voltage value, the second charging current, and the second voltage value; and adjusting a suitable charging current of the charging apparatus according to the cable impedance of the charging cable. Therefore, the terminal can adapt to different charging apparatuses, improving charging experience of a user.