Direct 48-/1-V GaN-Based DC-DC Power Converter With Double Step-Down Architecture and Master-Slave AO2T Control

• Published in: IEEE journal of solid-state circuits 2020-04, Vol.55 (4), p.988-998
• Main Authors: Yan, Dong, Ke, Xugang, Ma, D. Brian
• Format: Article
• Language: English
• Subjects: Adaptive control; Adaptive ON- and OFF-time (AO²T) control; Architecture; CMOS; Computer architecture; Delays; Density measurement; direct 48-/1-V power conversion; double step-down (DSD) architecture; elastic ON-time modulation; Energy conversion efficiency; Gallium nitrides; GaN-based power converter; Logic gates; Low level; master phase mirroring; Phase current; Power conversion; Power converters; Power efficiency; Power system measurements; Switches
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2019.2957237

In modern power delivery systems, there has been an up-rising trend of migrating conventional two-stage dc-dc power conversion architecture to a single-stage one, in order to accomplish better efficiency and power density. In response to such a trend, this article presents a gallium nitride (GaN)-based power converter design that achieves direct 48-/1-V dc-dc power conversion with a single-stage double step-down (DSD) architecture. Operating at 2 MHz, it pushes the equivalent minimum duty ratio to a record low level of 2.1%. In order to improve closed-loop regulation, an adaptive ON- and OFF-time (AO 2 T) control with elastic ON-time modulation is proposed for both steady-state and transient response enhancement. For reinforced reliability in the dual-phase operation, a master-phase mirroring technique enables adaptive master-slave phase operation, accomplishing automatic phase current balancing. An IC prototype is implemented on a 180-nm high voltage (HV) bipolar, CMOS DMOS (BCD) process, with an active die area of 1.46 mm 2 . It achieves peak efficiencies of 85.4%, 79%, and 56.8% at 100 kHz, 250 kHz, and 2 MHz, respectively.