Automatic On-Chip Backup Clock Changer for Protecting Abnormal MCU Operations in Unsafe Clock Frequency

Abstract

Mission-critical MCU-based systems under severe electrical situations cause malfunctioning by the disturbance in the clock path. MCU-based systems in clockless status loses their contrability in high-current output or glitch-clock injection may destroy status value of flip-flops. In this paper, we propose the automatic clock failure detection and protection by implementing a fully synthesizable edge detector, noise canceller logic and glitch-free clock changer circuit. To determine several noise-vulnerable data/clock paths, we propose a pre-simulation framework to reconstruct a clock noise propagation path from the entire circuit netlist. We successfully increased the noise immunity characteristics by allocating the detector units into efficient locations.