A low-volume multi-phase interleaved Dc-Dc converter for high step-down applications with auto-balancing of phase currents

This paper introduces a multi-phase interleaved dc-dc converter, targeted for high-step down applications including voltage regulator modules (VRM) for microprocessors, where low volume and high efficiency are the key priorities. The introduced architecture, reducing the voltage swing at the switching node, along with doubling the effective switching frequency of the inductor current ripple, allows reducing the size of the inductors by up to 4 times, resulting in superior dynamic regulation, while maintaining high power processing efficiency of above 90%. Along with the interleaved 2-phase operation of the introduced converter, practical implementation details, including gate driver implementation, startup, and additional features such as automatic phase current balancing, are also addressed. Experimental verifications with a 12-to-1.2 V, 10 A, 250 kHz prototype show proper functionality of the introduced converter.