Analysis and design of multiphase interleaved CRM Buck converter with wide load range

This paper presents a low-ripple wide-load-range LED driver with critical engineering value for industrial lighting systems. Based on a three-phase interleaved magnetically coupled Buck converter topology, the work systematically investigates the interaction between multi-phase coupled inductor current ripple and output current ripple. A normalized analytical model is developed to unveil the intrinsic characteristics of multi-phase magnetic coupling, explicitly demonstrating the advantages of synergistic integration between negative coupling coefficient design and critical conduction mode (CRM). The implemented prototype achieves constant-current output regulation across an ultra-wide range (3-33A, 1000% variation) under 480-600V input voltage, attaining a power density of 520W/in³. Experimental verification confirms that the system maintains output voltage self-adaptation with ripple suppression below 0.237% throughout the full load range, while delivering a peak efficiency of 98.23%, fully compliant with stringent design specifications.