Gan Fet

Electronic Specifier Editor Joe Bush spoke to Jim Witham, Chief Executive Officer of GaN Systems at electronica about the company’s offer of gallium nitride (GaN) power transistors and the role they are playing in the world’s energy reduction needs of the future.

The world is already consuming too much energy. As the global middle class grows, more energy will be required. Global warming and the resulting regulations, plus more stringent emissions standards, compound the issue. We are entering a revolution where materials and energy must be used more efficiently - meeting population and industrial energy consumption needs is not sustainable with current power system solutions. Power electronics must change.

Whenever power conversion happens, losses occur. These losses manifest themselves as waste heat, which has to be dissipated and gives rise to excess greenhouse gases. Using gallium nitride, with its much lower on-resistance, fast switching capabilities and zero reverse recovery losses, a more efficient conversion is achieved. GaN transistors are already making a difference in the consumer, data centre, industrial and transportation industries. Gallium nitride technology offers efficiency improvements over traditional silicon technology when used in high power conversion systems, thereby reducing greenhouse gas (GHG) emissions and various criteria air contaminants.

Hybrid and electric vehicles have a substantial power conversion requirement – a typical drivetrain can be switching 100kW. A typical silicon-based converter will be optimally 95% efficient – therefore having a five percent loss – or 5kW. These losses, as heat, have to be disposed of, and the current solutions involve water cooling and separate radiator systems. GaN converters can achieve 98 to 99% efficiency – a threefold reduction in losses, and thanks to GaN’s higher efficiencies, can be air-cooled. Other applications include solar, wind and smart grid and high efficiency power supply.

In addition to increased efficiency, systems that use gallium nitride require less components, are more compact and are lighter. Customers are replacing power MOSFETs and IGBTs with GaN transistors in order to reduce system size and weight by up to 5X; decrease power losses by up to 90%; reduce cost and BOM; and gain a competitive advantage.

GaN E-HEMTs (high electron mobility transistors) are being designed into a wide variety of power electronics applications. These applications include travel adapters, wireless chargers, smart home appliances, high efficiency AC/DC data centre power supplies, 48V to 1V direct converters, industrial motor drivers, distributed energy generation and storage systems, aerospace, automotive traction inverters, on-board EV battery chargers and DC/DC converters.

The properties of GaN allow for high current, high voltage and high switching frequency. This is exemplified by the lowest figure of merit (RDS(on) x QG) of all power transistor technologies available today. The ultra-fast switching capabilities with low losses, low on-resistance and superior thermal performance of GaN Systems’ devices combine to increase efficiency and power density in these applications.

At electronica GaN Systems launched a daughterboard style Evaluation Platform to help power design engineers easily evaluate the GaN E-HEMT performance in any system design, along with a universal motherboard (GS665MB-EVB). The family of four daughterboards ranging from 750W to 2,500W consists of two GaN Systems 650V GaN Enhancement mode HEMTs (E-HEMTs) and all necessary circuits, including half-bridge gate drivers, isolated power supplies and an optional heatsink to form a high performance half bridge power stage.