Eyal Aklimi, Student Member, IEEE, Daniel Piedra, Student Member, IEEE, Kevin Tien, Student Member, IEEE, Tomás Palacios, Member, IEEE, and Kenneth L. Shepard, Fellow, IEEE Hybrid CMOS/GaN 40-MHz Maximum 20-V Input DC–DC Multiphase Buck Converter. IEEE Journal of Solid-State Circuits, Volume: 52, Issue: 6, June 2017.

This paper presents a 40-MHz hybrid CMOS/GaN integrated multiphase dc–dc switched-inductor buck converter with a maximum 20-V input voltage. The half-bridge switches are realized using lateral AlGaN/GaN HEMTs, while the drivers and other circuitry are implemented in standard 180-nm CMOS. The interface between the CMOS and GaN dice is achieved through face-to-face bonding, reducing inductive parasitics for the connection to less than 15 pH. A capacitively coupled level shifter provides the gate drive for the high-side GaN switch using 5-V CMOS devices. The converter demonstrates 76% efficiency for 8:1 V conversion and over 60% efficiency for conversion ratios up to 16:1.