This paper presents a dual-phase Fibonacci hybrid converter with Gallium Nitride (GaN) switches for high step-down ratio, high power efficiency, and high current density. The proposed converter achieved 13:1 step-down ratio from input voltage to inductor-side switching nodes. This architecture reduces the converter area and alleviates the stress caused by short switch on-time, thereby minimizing switching transition loss. The equivalent output resistance in dual-phase interleaving operations is nearly half of that in a single-phase Fibonacci hybrid converter. Through the Fibonacci scalability, the proposed converter operates over 12-52V input voltage to 1V output voltage. The proposed converter demonstrates 91% peak efficiency at 500kHz under 1A load current and 1,113A/inch3 current density at 12A load current for a 52V to 1V conversion ratio.
