USB Type-C Port Controller Isolation for CC Pin Leakage
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Solution Overview
Problem
Current USB Type-C interface control circuits face inaccuracies in detect voltage due to leakage currents when devices are not powered, and the lower withstand voltage of transistors makes them unsuitable for existing designs.
Innovation Solution
A port controller device incorporating a pull-up resistor, switching circuit, enabling circuitry, and protection circuitry that selectively transmits supply voltage and limits current when the system is not powered, using transistors with lower withstand voltage and voltage generators to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current interface control circuit is used, then the device can operate with standard USB Type-C interface control, but leakage current from the channel configuration pin causes detect voltage inaccuracy and additional power consumption when the device is not powered
Solution Approach 1:
The patent extracts the problematic leakage current path by introducing a switching circuit that physically disconnects the channel configuration pin from the internal circuitry when the device is not powered. This isolation eliminates the leakage current source while maintaining the pin's external connectivity, directly resolving both the detect voltage inaccuracy and unnecessary power consumption issues.
Solution Approach 2:
The enabling circuitry generates control signals in advance based on power status detection, activating the switching circuit to turn off the signal path before leakage current becomes problematic. This preliminary action ensures the channel configuration pin is properly isolated whenever the device is not powered, preventing detect voltage errors and power waste before they occur.
2Ease of manufacture
If transistors with lower withstand voltage are used due to process development, then device manufacturing becomes more advanced and compact, but the transistors are no longer suitable for implementing the current interface control circuit
Solution Approach 1:
The protection circuitry provides beforehand cushioning by detecting when the supply voltage is not powered and generating control signals to limit current flow through the channel configuration pin. This protective mechanism prevents voltage spikes or excessive current from damaging the lower withstand voltage transistors, enabling their safe use in USB Type-C interface control circuits despite their reduced voltage tolerance.
Solution Approach 2:
The switching circuit acts as an intermediary between the channel configuration pin and the sensitive low-withstand-voltage transistors. By controlling the signal path activation, it mediates the interaction between external signals and internal transistor circuits, preventing direct exposure of the transistors to potentially damaging voltage conditions while maintaining functional operation.
Data Source
AI summary
A port controller device includes a pull-up resistor, a switching circuit, an enabling circuitry, and a protection circuitry. The pull-up resistor is configured to be coupled to a port, in which the port is configured to be coupled to a channel configuration pin of an electronic device. The switching circuit is configured to selectively transmit a supply voltage to the port via the pull-up resistor according to a first control signal, and turn off a signal path between the pull-up resistor and the port according to a second control signal. The enabling circuitry is configured to generate the first control signal according to an enable signal and the supply voltage. The protection circuitry is configured to generate the second control signal in response to a voltage from the port when the supply voltage is not powered, in order to limit a current from the port.