Influence of Deadtime on Si, SiC and GaN Converters

Abstract

This paper presents a comparison of three different transistor technologies Silicon Superjunction (Si SJ), Silicon Carbide (SiC) and Gallium Nitride (GaN) in respect to deadtime setting in a typical halfbridge converter. According to the measured results both new fast switching transistors SiC and GaN needs precise deadtime setting compared to the Si SJ devices. With wrong deadtime settings the converter efficiency drops more rapidly for GaN compared to SiC while the Si SJ device is the least affected by the deadtime length. The optimum deadtime in DC/DC converter can be found by tracking the maximum output voltage for given constant and compensated duty cycle and input voltage.