Efficiency of state-of-the-art GaN devices in a synchronous-rectifier buck converter

The Si devices have achieved their theoretical limits with the increasing of the switching frequency. The innovative GaN power switches present many advantages in power conversion systems, especially in terms of efficiency and size. The use of GaN transistors will be strongly exploited in the automotive applications due to these features. Indeed, the so-called point of loads require an increasing attention, in particular for the 48V-12V electric system architectures. In this paper the reduction of the energy losses achievable thanks to commercial GaN devices is analyzed by a simple circuit model. The effectiveness of the model is validated by experimental measurements in a synchronous buck converter. The results confirm that a remarkable efficiency improvement with the current GaN technology may be already reached.