Current mode switching power supply overload protection circuit with false fault condition screening

摘要

The invention relates to a switching power supply having a protection device to shut down the supply of the output voltage in the presence of a fault condition such as an overload. The invention identifies potential fault conditions when the voltage control feedback loop is out of regulation and screens out false fault conditions during periods when the duty cycle of the control signal is below a specified duty cycle limit. The invention further shuts down the supply of the output voltage when the bulk line voltage provided to the power supply is below a specified limit.