A simple open-circuit fault detection method for a fault-tolerant DC/DC converter

This paper presents a two-switch step-down converter topology with fault tolerant capability. The proposed fault detection method uses the source-to-ground voltage of the floating MOSFET to identify the fault. If an open-circuit fault on the MOSFET occurs, the source voltage will become zero. The micro-controller which detects the fault will activate an alternative path through another MOSFET to maintain converter output regulation. The redundancy concept which is applied to this topology uses the same output inductor and capacitor to operate the converter in buck mode during normal operation and in buck-boost mode after fault. Experimental results are reported to confirm the design and demonstrate the fault tolerant operation.