The single reference Bi-Directional GaN HEMT AC switch

A novel device, the Single Reference Bi-Directional [SRDB] GaN HEMT AC Switch is presented in this paper from an application engineer's point of view. First, the device structure and the main characteristics are introduced. In a second part, the device is implemented in an AC chopper circuit to demonstrate it's hability to switch an AC current from an AC voltage source, then a DC chopper is used to set the device into a switching cell.

Introduction

Bi-Directional AC switches are the main ingredient to the promising and yet demonstrated matrix structure for AC/AC power converters [1], [2], [3], [4]. Using GaN to produce Bi-Directional Switches has also been the focus of patent applicants such as in [5]. A Bi-Directional GaN HEMT AC Switch has been studied and presented in a matrix converter application in [6]. It is controlled by two gate circuits, one for each polarity of the Drain voltage. Those gate circuits are well described in [7], they use microwaves to transmit energy along with the control signal. In a different paper [8], it has been demonstrated an AC switch using GaN HEMTs, in that case the AC switch is obtained by connecting two separate components. Very recent work in our institution has shown that a different AC switch could be produced using a Single reference electrode on a single device, hence reducing the number of Gate drivers needed. It is the first time that this SRBD component is presented.