2024-03 | Youssef Elasser, Jaeil Baek, Kaladhar Radhakrishnan, Houle Gan, Jonathan P. Douglas, Harish K. Krishnamurthy, Xin Li, Shuai Jiang, Vivek De, Charles R. Sullivan, Minjie Chen
This article 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 regulator module (VRM) called the Mini-LEGO. The Mini-LEGO converter provides vertical power delivery and achieves a peak efficiency of 87.1%, a full load efficiency of 84.1%, and a power density of 1390 W/in³. The converter features a compact device implementation, simple gate drive circuitry, and a fast regulation-stage switching frequency of 1.5 MHz. The key contributions include the design of a novel coupled inductor geometry for vertical power delivery, which reduces the inductor height from 5.25 mm to 2.5 mm, and a loss-based optimization method for the coupled inductor. The Mini-LEGO converter is packaged within a modified LGA socket for CPUs, leveraging the cooling resources of the CPU. The article also discusses the operation principles of the LEGO-PoL architecture, the design methodology of the Mini-LEGO converter, the gate drive circuitry, and the thermal analysis of the prototype.This article 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 regulator module (VRM) called the Mini-LEGO. The Mini-LEGO converter provides vertical power delivery and achieves a peak efficiency of 87.1%, a full load efficiency of 84.1%, and a power density of 1390 W/in³. The converter features a compact device implementation, simple gate drive circuitry, and a fast regulation-stage switching frequency of 1.5 MHz. The key contributions include the design of a novel coupled inductor geometry for vertical power delivery, which reduces the inductor height from 5.25 mm to 2.5 mm, and a loss-based optimization method for the coupled inductor. The Mini-LEGO converter is packaged within a modified LGA socket for CPUs, leveraging the cooling resources of the CPU. The article also discusses the operation principles of the LEGO-PoL architecture, the design methodology of the Mini-LEGO converter, the gate drive circuitry, and the thermal analysis of the prototype.