Efficiency and Near-Field Emission Comparisons of a Si- and GaN Based Buck Converter Topology

New GaN transistors on the market offer the possibility to replace the traditional Si MOSFET transistors even in low power DC-DC converter circuits, to achieve smaller designs due to their higher switching frequency capability and also to increase the efficiency. The presented paper figures out the main losses within each transistor technology and compares the latest measurements done on a hard switching DC-DC buck converter topology. Beside the investigation of the influence of a changing switching frequency and different load current ratings, also the generated EM emissions are quantified with an EM scanner unit. The results show that the GaN technology is a competitive technology to replace traditional Si MOSFET transistors in such a power supply application.