Electronic Control Apparatus Gate Drive Circuit Fault Detection

The patent introduces a feedback mechanism by monitoring the gate voltage through the gate resistor. The control circuit continuously checks the voltage across the gate resistor to detect abnormalities in the ON-drive constant-current circuit. When an abnormality is detected (such as failure to discharge gate charge properly), the control circuit can identify the fault condition and take appropriate action, thus resolving the contradiction between reliable switching and abnormality detection.

The gate resistor serves as an intermediary element that enables abnormality detection. By monitoring the voltage across this resistor, the control circuit can indirectly detect abnormalities in the ON-drive circuit without directly interfacing with the gate drive transistors. This intermediary approach allows the system to detect faults while maintaining the reliability of the power transistor switching operation.

The control circuit performs multiple functions: it controls the OFF-drive switching element to discharge gate charge, monitors the gate voltage through the gate resistor for abnormality detection, and can take protective actions when faults are detected. By making the control circuit multi-functional, the patent prevents thermal damage without adding separate dedicated detection hardware, thus resolving the contradiction between protection capability and circuit complexity.

The system uses its existing gate resistor and control circuitry to perform self-diagnosis. The control circuit monitors its own operation by checking the voltage across the gate resistor, which reflects the state of the ON-drive circuit. This self-service approach enables abnormality detection and thermal damage prevention without requiring additional external monitoring equipment, thereby avoiding increased device complexity.