Think of it as a tax or a toll. It’s the power that is lost every time electricity is converted from one form to another, and it can really add up. The conversions themselves cannot be avoided, but new technologies and materials are significantly reducing the amount of loss incurred when they happen. Among the most promising is GaN, gallium nitride, which is replacing silicon and competing with silicon carbide (SiC) in a variety of switching applications.
GaN’s performance advantage comes from several of its characteristics. The material’s high critical field, the highest magnetic field under which a material remains superconducting, allows GaN-based devices to operate at higher voltages and lower leak currents than silicon-based devices. The material’s higher electron saturation velocity, the maximum velocity an electron reaches in a high electric field, lets it outperform silicon at high frequency. And its electron mobility, how quickly an electron can move through it, outperforms even SiC. In short, for today’s high-voltage high-frequency applications nothing beats GaN. Compared to the alternatives, GaN switches are light, compact, fast, efficient, and cool running. The challenge is to match GaN’s performance in other components of a device and prevent to creation of bottlenecks.
One of the key components in high-speed switching applications is transformers and PFC inductors, and if those magnetics are not appropriately designed for use with GaN switches, the benefits of GaN can be lost. Peak performance at GaN’s high switching frequencies can depend on magnetic devices’ core material; leakage inductance, and capacitance management; and wire selection. The next three posts to the blog will address those characteristics and their significance in choosing GaN-ready magnetics.