Isolated Gate-Drive Signal Transmission With GND Open Detection

The patent introduces a second external terminal as an intermediary element that connects to the secondary circuit system's ground. This terminal serves as a mediator that allows the primary circuit system to indirectly monitor the ground connection status of the secondary system through voltage monitoring, without requiring direct access to the secondary ground point. The open detection circuit monitors the terminal voltage at this intermediary terminal to detect ground open faults.

The patent replaces complex direct ground fault detection methods with an electrical voltage monitoring approach. Instead of using direct electrical connection or mechanical sensing methods to detect ground faults, the invention uses the natural voltage variations that occur at the second external terminal when ground connections are compromised. This substitution simplifies the detection mechanism while maintaining reliability.

The second external terminal is designed to serve multiple functions: it provides electrical isolation between primary and secondary systems, establishes a reference point for voltage monitoring, and enables ground fault detection. By making this terminal multi-functional, the patent avoids adding separate dedicated components for each function, thereby improving measurement precision without proportionally increasing device complexity.

The monitoring system utilizes the inherent voltage characteristics of the second external terminal itself for detection purposes. The terminal's voltage naturally varies when ground connections are compromised, and this self-generated signal is used for detection without requiring external test signals or additional active components. The system essentially monitors itself through the behavior of its own terminal.