USB Cable Detection Circuit Using Variable Resistor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing USB cable detection methods face errors due to parasitic capacitors on the ID line, leading to incorrect determination of USB plug types during the detection process.
Innovation Solution
A device and method utilizing a detection circuit with a variable resistor, controlled by a control unit through multiple on-off states, to adjust resistance values and enhance detection accuracy by compensating for parasitic capacitors, ensuring accurate determination of USB cable types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed resistors and capacitors are connected in series between VBUS line and ID line to identify different types of connected plugs, then the detection circuit can determine cable types, but parasitic capacitors on the ID line cause signal attenuation and detection errors
Solution Approach 1:
The patent applies the dynamics principle by replacing fixed resistors with variable resistors in the detection circuit. The variable resistor can dynamically adjust its resistance value based on detected signal conditions, allowing the circuit to adapt to varying parasitic capacitance effects and maintain accurate detection across different cable types and configurations.
Solution Approach 2:
The patent implements parameter changes by modifying the resistance values in the detection circuit during the detection process. By changing resistance parameters dynamically, the circuit compensates for signal attenuation caused by parasitic capacitors and accurately determines cable types despite the presence of these unwanted capacitances.
2Measurement precision
If multiple switches and variable resistors are added to the detection circuit to compensate for parasitic capacitors, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a detection circuit where the variable resistor and switches serve multiple functions: they both compensate for parasitic capacitance effects and enable identification of different cable types. This multi-functionality reduces the need for separate compensation circuits, thereby limiting the increase in overall device complexity.
Solution Approach 2:
By using parameter changes through variable resistors and switches, the patent achieves accurate cable type detection without requiring multiple fixed circuits. The dynamic adjustment of resistance parameters provides a compact solution that improves detection accuracy while maintaining relatively simple circuit architecture.
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 solution significantly reduces errors in USB cable type detection by allowing the variable resistor to adjust within a specific range, thereby improving detection accuracy even in the presence of parasitic capacitors.
Implementation Method 1
The detection circuit includes a signal source, a receiving end, a first resistor, a second resistor, a variable resistor... The control unit is configured to control the variable resistor and the signal source to transmit the detection signal respectively corresponding to the plurality of on-off states
Implementation Method 2
The signal is substantially attenuated by the parasitic capacitor on the ID line. The generation of parasitic capacitors on the ID line are caused by the following reasons: the parasitic capacitors on the ID soldering pad, generated by the wires between the ID soldering pad and the receptacle on the printed circuit board (PCB)
Data Source
AI summary
A detection device for detecting types of a universal serial bus cable includes a detection circuit and a control unit. The detection circuit includes a signal source, a receiving end, a first resistor, a second resistor, a variable resistor, a first capacitor, a second capacitor, first through fourth switches, a VBUS end, an ID end, and a ground end. The signal source provides a detection signal. The control unit is electrically connected to the detection circuit, and is configured to control the first through the fourth switches according to a plurality of on-off states, to receive the detection signal and a VBUS signal from the receiving end in the plurality of on-off states, to generate a plurality of detection results, and to determine the type of the USB cable according to the plurality of detection results.