Advanced clock synchronization circuit for switch mode power supplies

摘要

In a switch mode power supply, a circuit and method for switching between an internal clock and an external synchronization clock when a stable external clock has been detected, and for switching back to operating the power supply using said internal clock when a predetermined number of sequential external clock pulses exceed a predetermined switching period dropout threshold or are otherwise missing. In one embodiment, a power system comprises a plurality of power supplies connected in parallel to a common load and where each power supply is synchronized to the external clock when a stable external clock has been detected by each.