Current Comparator Overvoltage Protection Circuit for USB Connectors
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Solution Overview
Problem
Existing overvoltage protection circuits in USB connectors face challenges in quickly detecting overvoltage events while minimizing leakage current and maintaining a fast response time, which is crucial for protecting devices from damage.
Innovation Solution
The proposed overvoltage protection circuit incorporates a current comparator with a transistor and a bias current generator, along with a clamp circuit, to quickly detect voltage levels and generate an overvoltage protection signal, thereby activating the USB switch to prevent damage. This solution includes a reference voltage generator and a current mirror to enhance detection speed and reduce leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing overvoltage protection circuits are used, then the device can be protected from overvoltage damage, but the response time for detecting overvoltage events is slow and leakage current is high
Solution Approach 1:
The patent changes the detection parameter from voltage-based to current-based detection. By using a current comparator instead of a voltage comparator, the circuit detects overvoltage events through current changes, which provides faster response time while maintaining protection reliability
Solution Approach 2:
The patent replaces the traditional voltage comparison mechanism with a current comparison mechanism. The current comparator circuit substitutes the voltage detection approach, enabling faster response to overvoltage events through current-based detection
2Reliability
If existing overvoltage protection circuits are used, then the device can be protected from overvoltage damage, but the leakage current is high
Solution Approach 1:
The patent changes the operating parameter from voltage-based detection to current-based detection. This parameter change results in significantly reduced leakage current while maintaining the overvoltage protection function through the current comparator circuit
3Productivity
If the USB switch is activated during overvoltage event, then the device can operate normally, but the device may incur damage from high voltage
Solution Approach 1:
The patent implements preliminary protective action by detecting overvoltage events before they can cause damage to the device. The current comparator continuously monitors current and triggers the switch to open before harmful voltage levels can affect the protected device
Solution Approach 2:
The patent applies preliminary anti-action by preparing the protection mechanism in advance. The circuit is designed to immediately counteract overvoltage threats through rapid switch opening, preventing the harmful voltage from reaching the device
Data Source
AI summary
According to an aspect, an overvoltage protection circuit includes a bias current generator configured to generate a bias current, and a current comparator configured to receive the bias current and a voltage associated with a data terminal of a connector. The current comparator includes a transistor. The transistor is configured to activate based on a level of the voltage associated with the data terminal. The current comparator is configured to compare a current of the transistor with the bias current. The overvoltage protection circuit includes an output circuit configured to generate an overvoltage protection signal in response to the current of the transistor being greater than the bias current.