Integrated dc-dc based-GaN converter with screen printed capacitors allowing double side cooling

Converter topology, power devices, passives elements and technology are the keys elements to achieve highly efficient and integrated converters. This article discusses each of these items with a point of load converter application in mind. The potential advantages of series connection are discussed: increase of both the specific power and the efficiency, reduction of semiconductors voltage rating and amplitude of the dV/dt, increase of the apparent switching frequency. The aim of this paper is to investigate how the advantages of the versatile Flying Capacitor topology (DC/DC or DC/AC conversion) can be combined with those of gallium nitride (GaN) power transistors. Integrated screen-printed capacitors are also investigated to reduce parasitic elements and allow double side cooling. A 48V to 5V prototype with screen-printed flying capacitors is built to show the feasibility of such a solution.