A 12-Level Series-Capacitor 48-1 V DC–DC Converter With On-Chip Switch and GaN Hybrid Power Conversion Haixiao Cao ,X uY a n g , Chenkang Xue

Abstract

This work presents a 48-1 V dc–dc converter with an on-chip switch and gallium nitride (GaN) hybrid power conver- sion. By series connecting a 12-level Dickson switched-capacitor with a two-phase switched-inductor circuit, the capacitors take over most of the 48-V voltage stresses. The circuit, thus, reduces to an equivalent 4-1 V converter, making the on-chip 5-V tran- sistor applicable for a 48-V high-voltage design. Due to the easy integration of on-chip switches and superior switch figures of merit over other 48-1 V counterparts, this proposed design is able to achieve the highest switching frequency, the lowest external switch count, and the improved power density compared with other prior-state-of-the-ar ts. The prototype was fabricated using a 0.18- µm BCD process with an evaluation board volume of 17 mm × 15 mm × 2.6 mm. The converter achieves a maximum 8-A loading capacity with the input range from 36 to 60 V and the output from 0.5 to 1 V . The measured peak power efficiency is 90.2%, and the power density is 998 A/in 3 considering the power stage volume.