Background With the continuous development of radar antenna systems and high-performance field-programmable gate arrays (FPGAs), point-of-load (POL) power supplies are required to provide increasingly large output currents while maintaining a high step-down ratio, high power density, and an ultralow profile. Vertical power delivery can effectively reduce power distribution network losses by shortening the high-current conduction path; however, it imposes stringent restrictions on the height and volume of the POL converter. Conventional high-step-down solutions based on magnetic isolation or multistage conversion generally suffer from bulky magnetic components and increased switching losses at high operating frequencies.

Purpose This study aims to develop an ultrathin, high-current POL power supply for radar antenna systems, capable of converting a 28 V intermediate bus voltage to 1.2 V/60 A while achieving high efficiency, high power density, and a module height suitable for vertical power delivery applications.

Methods A two-stage hybrid switched-capacitor topology was proposed. The first stage employs a hybrid switched-capacitor synchronous Buck converter to convert 28 V to 8 V, while the second stage uses a two-phase interleaved synchronous Buck converter to regulate the output to 1.2 V and provide high output current. The operating modes and soft-switching characteristics of the first-stage converter were analyzed. Key circuit parameters were designed and optimized considering voltage ripple, current ripple, efficiency, and device stress. To minimize the converter height and magnetic losses, the winding stack-up and layout of the planar inductors were optimized using finite-element simulations in Ansys Maxwell. The overall converter performance was further verified by SIMPLIS simulations and prototype experiments. A 40 mm × 40 mm × 4 mm prototype was developed.

Results At an input voltage of 28 V and an output of 1.2 V/60 A, the prototype achieved a full-load efficiency of 88.26% and a power density of 19.53 W/cm³. The peak efficiency reached 90.86% at an output current of 30 A. The first-stage and second-stage simulated full-load efficiencies were 96.45% and 91.65%, respectively. The measured thermal performance also demonstrated reliable operation under high-current conditions and over a wide ambient-temperature range.

Conclusions The proposed two-stage hybrid switched-capacitor POL architecture effectively combines a high step-down ratio, high-current capability, and an ultrathin structure. The optimized magnetic design and converter topology enable compact vertical power delivery for radar FPGA loads and provide a promising solution for other space-constrained, high-power-density low-voltage power supply applications.