T40.1 - Mini-LEGO: A 1.5-MHz 240-A 48-V-to-1-V CPU VRM with 8.4-mm Height for Vertical Power Delivery

This paper presents the design and optimization of a miniaturized 48-V-to-1-V 240-A linear-extendable group operated point-of-load (LEGO-PoL) CPU voltage regulation module (VRM) - Mini-LEGO - with 336 mm^2 area and 8.4 mm height for vertical power delivery. The Mini-LEGO features compact device implementation, simplified gate drive circuitry, optimized magnetics, and switches at 1.5 MHz. The overall converter area, including all power stage and gate drive circuitry, is 336 mm^2 with 0.71 A/mm^2 current area density. The vertical coupled inductor delivers 80 A with a thickness of 2.5 mm. It achieves a peak efficiency of 87.1%, a full load efficiency of 84.1%, and a power density of 1,390 W/in^3 with the maximum device junction temperature maintained below 100 degrees C after five minutes of full-load operation.