Health monitoring of POL converter using digital PWM controller

In the aerospace industry, interest has been growing in monitoring the ongoing health of electronic products and systems to predict failures and provide early warnings for any catastrophic failures. Switch-mode power supplies form an integral part of the avionic line replaceable unit (LRU). Any failure in its operation will cause malfunctioning of the complete electronics and the system thereafter. Point-of-load (POL) converters in particular are non-isolated buck converters that provide low output voltage DC power close to the loads. In the last decade, the average LRU supplies evolved from a basic four output voltages to more than twenty output voltages, due to the increased number of low-voltage supply pins on Very Large Scale Integrated (VLSI) circuits. This increased number of POL converters mathematically increases power supply failure rates, hence the importance of being able to predict them. This paper presents a brief review of failures/degradation experienced by POL converters in avionic systems. Capabilities of currently used analog Pulse-Width Modulator (PWM) controllers and the digitally-controlled PWMs for health monitoring of electronic systems are addressed. Lastly, the technique of system identification for health monitoring of POL converter using Digital Pulse-Width Modulator (DPWM) circuits is proposed.