LEGO-PoL: A 93.1% 54V-1.5V 300A Merged-Two-Stage Hybrid Converter with a Linear Extendable Group Operated Point-of-Load (LEGO-PoL) Architecture

This paper presents a merged-two-stage Linear Extendable Group Operated Point-of-Load (LEGO-PoL) architecture targeting applications with high voltage conversion ratio and very high output current (a few hundreds Amps). In the merged-two-stage LEGO-PoL architecture, many switched capacitor units are connected in series to split the input voltage into multiple voltage domains, and many buck units are connected in parallel to split the output current into multiple current paths. One submodule of the LEGO-PoL architecture merges the operation of a switched capacitor unit and a multi-phase buck unit to create mutual advantages. The buck units are used as current sources to soft-charge and soft-switch the switched capacitor units, and the switched capacitor units are utilized to ensure current sharing among a large number of buck units. The LEGO-PoL architecture can be linearly-extended to cover wide input voltage range and output current range. The modular units are group-operated to ensure voltage balancing and current sharing automatically. A 450W, 54V-1.5V, 300A LEGO-PoL architecture with a peak efficiency of 93.1% has been built and tested to verify the effectiveness of the proposed approach.