G-Sound: GaN Chips for Class-D Audio Amplifiers

The aim of this project "G-Sound" is to identify the commercial and technical challenges and opportunities for exploiting a disrupting Gallium Nitride (GaN) technology in the market of audio amplifiers.

GaN is widely regarded as the most promising semiconductor for power devices since silicon (Si) and the devices based on it offer significantly better on-state resistance and breakdown performance as well as fast switching and smaller size, all of which are needed to develop compact, efficient audio amplifiers with state-of-the-art music quality.

Class-D audio amplifiers are becoming increasingly popular, for several reasons: (i) significantly higher efficiency (ii) higher power density and (iii) higher reliability due to lower losses and heat generated. While present in low-cost and low-to-medium performance products, their adoption in more audiophile designs, high performance and professional devices has been much slower. The reason is the compromised music quality because of the limitations imposed by the Si-transistors used today. The switching behaviour of Si-transistors is poor in terms of noise and distortions, as well as creating transient losses. In this project, G-Sound, the SME "Cambridge GaN Devices (CGD)" will investigate GaN-transistor modules for audio-applications, eliminating most of the drawbacks of current class-D audio amplifiers. Such improvements in device and system performance lead to reduced distortions and noise at increased switching frequencies while maintaining very high efficiencies. The result could be a technology breakthrough and widespread adaptation of the class-D audio amplifiers.

The way people use and "consume" music and media has dramatically changed over the last couple of years. The music market has mostly moved from physical media such as CDs to digital files available on internet and cloud and streaming services. Moreover, the number of speakers has increased exponentially: today speakers are present in every room of our homes, in portable and smart devices, in mobile phones, tablets, smart watches, to name a few. All these applications are striving for better sound quality, lower power consumption and smaller size. Streaming service providers such as Spotify or Amazon are starting to market high-resolution music and sound streaming requiring new high-quality audio systems. These trends have a tremendous impact on the addressable market for GaN-based technology. Given the disruptive advantages of its technology, in terms of cleanness of switching and reduction of parasitics due to multi-chip integration, CGD is in a unique position to capitalise on this opportunity and become a major player in delivering solutions for audio industry.