USB Switching Circuit Voltage Regulation for DisplayPort Leakage
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Solution Overview
Problem
USB hosts operating in DisplayPort alternate mode may incorrectly determine the connection state of external devices due to leakage currents from multiplexers, leading to erroneous operations.
Innovation Solution
A USB switching circuit comprising a first multiplexer, a second multiplexer, and a voltage regulation circuit, which distributes data signals and sets voltage levels to prevent incorrect switching and leakage currents by ensuring the maximum and minimum voltages of the data signals correspond to a common voltage, thereby preventing erroneous operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If USB Type-C interface is used with DisplayPort alternate mode to achieve multi-functionality, then the interface versatility is improved, but leakage currents from multiplexers cause erroneous determination of connection state
Solution Approach 1:
The patent introduces a voltage regulation circuit as an intermediary component between the DisplayPort data signals and the USB multiplexer control signals. This mediator regulates the voltage levels of DP data signals to match USB voltage standards, preventing erroneous switching caused by voltage conflicts while maintaining both DisplayPort and USB functionalities through the same physical interface
Solution Approach 2:
The patent changes the voltage parameter of DisplayPort data signals by introducing a voltage regulation circuit that converts DP voltage levels to USB voltage levels. This parameter transformation allows the same physical pins to safely carry different signal types without causing erroneous switching in the USB multiplexer, thereby resolving the reliability issue while maintaining versatility
2Device complexity
If multiplexers are used to switch between DisplayPort and USB modes, then the device complexity is reduced, but leakage currents cause erroneous switching operations
Solution Approach 1:
The voltage regulation circuit serves as a mediator that prevents direct conflict between DisplayPort data signals and USB multiplexer control signals. By regulating voltages before they reach the multiplexer, it eliminates erroneous switching caused by leakage currents while maintaining the simplified single-interface structure
Solution Approach 2:
The patent applies beforehand cushioning by preemptively regulating the voltage levels of DisplayPort data signals before they can cause erroneous switching in the USB multiplexer. This preventive measure ensures that even when DP signals are present, they cannot trigger incorrect switching operations, thus maintaining reliability without increasing structural complexity
Data Source
AI summary
A USB switching circuit includes a first multiplexer, a second multiplexer coupled with the first multiplexer through transmission paths, and a voltage regulation circuit coupled with the first and second multiplexers. The first multiplexer distributes first data signals to the transmission paths according to first control signals. The second multiplexer distributes a second data signal to the transmission paths according to second control signals. The voltage regulation circuit sets a maximum voltage and a minimum voltage of the first data signals to corresponding to a common voltage. The maximum voltage of the first data signals is not higher than a maximum voltage of the second control signals, or the minimum voltage of the first data signals is not lower than a minimum voltage of the second control signals. The first data signals and the second data signal are generated according to different communication protocols.