Power supply fault protection circuit with primary side shutdown and restart

Abstract

Fault protection circuitry and methodologies for isolated power supply topologies are provided. The circuitry is configured to shut down the primary side of the supply in case of a system fault, while keeping the secondary side circuit running, thus offering flexibility for restarting upon clearing of the fault. A lighting driver thus configured with safety isolation and a secondary side microcontroller or other control circuitry, is configured so that the circuit can shut down the primary side in response to system fault detection, while keeping the secondary microcontroller running from an energy storage circuit (e.g., bulk capacitor in parallel with load). The driver operation can resume with a controlled timing if the fault is cleared. The number of restarts may be limited, and/or a timer may be used to space restarts. The driver may be used with loads other than lighting-based loads, as will be appreciated.