Design and evaluation of a 10 MHz gallium nitride based 42 V DC-DC converter

Gallium nitride (GaN) based power devices are becoming common place due to their ability to achieve higher efficiencies and higher switching frequencies than is possible with silicon (Si) power MOSFETs. With discrete eGaN® FETs capable of switching at slew rates beyond 40V/ns, the system performance is greatly impacted by aspects outside the power devices, such as high speed gate drivers and printed circuit board (PCB) layout. In this paper, these limitations are identified and discussed while demonstrating the ability of new family of high frequency enhancement mode gallium nitride power transistors. These devices were designed to address high-frequency hard-switching power applications not practical with Si MOSFETs, thus enabling applications requiring high-frequency at higher voltages. As demonstrator a 42 V, 10 MHz, 40 W buck converter suitable for envelope tracking is presented showing a peak efficiency of over 89%.