Fault- Tolerant DC-DC Converter with Zero Interruption Time Using Capacitor Health Prognosis

A high-end critical electronic system is expected to have hundreds of electronic subsystems, which rely on the Power Management Unit (PMU) to be energized. Having an efficient PMU is crucial and it requires reliable and well-structured voltage buck converters to translate the supplied voltage levels. The buck converters employed in PMU are expected to be fault tolerant and supply uninterrupted power while serving critical subsystems. Active redundant parallel buck converters employed in PMU to achieve fault tolerance increases overhead in terms of area, cost and power dissipation. In this paper, a DC-DC converter is designed for the PMU by combining two legs of buck converters with an effective output of 3.3 V. A simple yet effective technique is proposed to design a fault-tolerant buck DC-DC converter by bypassing a faulty converter leg. The proposed system utilizes an online signal processing-based method for prognostic fault detection. Ripple content in the voltage of the output Aluminum Electrolytic Capacitor (AEC) is monitored and used as a primary health indicator for the primary buck converter leg. Increase in the output ripple due to degradation is used for the prognosis of primary converter failure. The secondary buck converter leg is activated only upon the confirmed prognosis of a faulty primary converter leg to avoid false triggering. The timely prognosis of primary converter failure and activation of secondary converter facilitates uninterrupted power supply. An experimental setup is built and tested in the laboratory. Experimental results indicate a smooth transition from the primary converter leg to the secondary demonstrating an uninterrupted power supply along with the simplicity and effectiveness of the proposed solution