USB-C Overvoltage Protection via SBU Switch Control
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Solution Overview
Problem
USB Type-C connector systems are susceptible to electrical damage due to overvoltage conditions, which can cause overcurrent, overheating, and other faults, particularly in devices using Field Effect Transistors (FETs) for power transfer.
Innovation Solution
An integrated circuit (IC) controller with on-chip overvoltage protection circuitry is implemented, including a high-voltage tolerant internal VCONN/SBU switch with fast over-voltage detection to turn off the switch and prevent backflow current, protecting the VCONN/SBU switch and VCONN supply from electrical and thermal damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If FETs are used for power transfer in USB-C connector systems, then power transfer capability is improved, but susceptibility to electrical damage from overvoltage conditions worsens
Solution Approach 1:
The patent implements preliminary protective actions by incorporating overvoltage detection circuitry and protection mechanisms that activate before damage occurs. The system continuously monitors voltage levels and preemptively triggers protection modes when threshold violations are detected, preventing overvoltage damage to FETs and other sensitive components before it can occur.
Solution Approach 2:
The patent introduces intermediary protection circuitry between the power source and the FETs. This intermediary layer includes overvoltage detection circuits, protection transistors, and control logic that act as a buffer, detecting voltage anomalies and isolating sensitive components before they suffer damage, thus mediating between the power transfer function and component protection requirements.
2Reliability
If overvoltage protection circuitry is added to USB-C connector systems, then protection against electrical damage is improved, but device complexity worsens
Solution Approach 1:
The patent merges overvoltage protection functions with existing USB-C controller circuitry. The protection logic is integrated into the same control chip that manages power delivery and data communication, combining multiple functions (power management, communication, and protection) into a single unified controller, thereby reducing overall device complexity despite adding protection capabilities.
Solution Approach 2:
The patent implements universal protection circuitry that serves multiple functions: overvoltage detection, overcurrent protection, and fault isolation. The same protection mechanisms protect various components (FETs, capacitors, communication circuits) across different USB-C configurations, making the protection system multi-functional and reducing the need for separate dedicated protection circuits for each component.
Data Source
AI summary
An example electronic device includes a first switch and a second switch that are each coupled to an overvoltage detection and protection circuit. The first switch is configured to connect a first sideband use (SBU) terminal of a Universal Serial Bus Type-C (USB-C) controller to a SBU crossbar switch of the USB-C controller. The second switch is configured to connect a second SBU terminal of the USB-C controller to the SBU crossbar switch. The overvoltage detection and protection circuit is configured to deactivate the first switch or the second switch when a voltage exceeding a predetermined threshold is detected on a terminal of the first switch or the second switch.