Overview of fault diagnosis and detection methods used in Switched Mode Power Supplies

Diagnosis and detection of faults in a switching regulator plays an important role in safety critical application. This paper briefs about the causes for the failure of semiconductor components used in the power supply design and on the methods used to detect failure of components like MOSFET, diode and output filter capacitor. It also briefs on the approaches followed to indicate power supply failure and on the approaches used to avoid false indications in response to transients. Most of the battery chargers operate at increased switching frequency during the transition from constant current to constant voltage region. This paper applies above method to switching regulators in order to avoid auto restart in response to momentary overload. In this paper, names - power supply, regulator, and switching regulator represent Switched Mode Power Supplies (SMPS).