Hybrid synchronous DC-DC buck power converter using Si and GaN transistors

Usage of power converters in a vast variety of equipments from cellphones, laptops to automobiles, aeroplanes and satellites is increasing. Different synchronous buck converter configurations are considered in this work using Silicon (Si) devices and Gallium Nitride (GaN) devices of equal current ratings. The performance of these converters in terms of power losses and overall efficiency are compared. It is shown that the usage of GaN devices instead of Si devices reduces the power losses and improves the overall efficiency of the power converter. A hybrid synchronous buck converter topology consisting of one Si device and one GaN device is shown to have the lowest rated power loss for switches with similar ratings. The usage of GaN device as active switch and the Si device as synchronous diode is beneficial and has the highest efficiency among the possible converter configurations with an improvement in efficiency by 3-5% for rated conditions.