GAN versus CoolMOS: A theoretical comparison of performances

The present silicon based devises such as IGBT and MOSFET operate at low switching frequencies of about 40 kHz and 100 kHz respectively. This means that we need to have some other new device that can switch in the range of MHz and which is more efficient than the silicon based devices. As for as high speed devices are concerned, we have SiC and GaN devices. Although SiC is an efficient and matured device, it is found to be costlier (10 times) than silicon based devices. Due to this, its application is limited to high power converters. The next emerging power electronic device is GaN (Gallium nitride). Only few manufacturers have released the product in low voltage and current level. As for as the cost is concerned, by 2015, it will be within the range of today´s silicon device price. GaN device offers five key characteristics: high dielectric strength, high operating temperature, high current density, high speed switching and low on resistance. In this paper we present the results of the mathematical model developed to characterize the switching and conduction losses in GaN and CoolMOS switches. GaN device models are then used in a 500W DC-DC Boost converter to calculate efficiency and compared with that of CoolMOS device.