A 48V Input Merged Cross-Connected Double Step-Down Converter with Package-Integrated GaN Switches and Silicon Controller IC

This paper presents a new hybrid converter with a capacitive dual-path, merged cross-connected (CC) double step-down (DSD) to achieve high efficiency with 24% conduction loss reduction and 25% switching loss reduction. The flip-chip GaN devices, silicon gate drivers with a controller chip, flying capacitors, and bootstrapping (BST) capacitors are heterogeneously integrated on an organic package, a system in package (SiP) implementation to enable high-frequency operation. The simulated peak efficiencies are 93.6% and 84.8% for 48V-to-3V and 48V-to-1V conversions, respectively, at 2.5MHz.