A 12-Level Series-Capacitor 48-1V DC–DC Converter With On-Chip Switch and GaN Hybrid Power Conversion
Haixiao Cao, Xu Yang, Chenkang Xue, Lenian He, Zhichao Tan, Menglian Zhao, Yong Ding, Wuhua Li, Wanyuan Qu
Abstract
This work presents a 48-1V dc–dc converter with an on-chip switch and gallium nitride (GaN) hybrid power conversion. 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 4-1V converter, making the on-chip 5-V transistor 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 48-1V 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-arts. The prototype was fabricated using a 0.18- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> BCD process with an evaluation board volume of 17 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 15 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 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 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> considering the power stage volume.