GaN power FET half bridge evaluation board aids circuit design

November 08, 2015 // By Graham Prophet
GaN Systems (Ottawa, Canada), maker of gallium nitride power transistors, has a Half-Bridge Evaluation Board which demonstrates the performance of its GaN enhancement mode power semiconductors in real power circuits.

The fully functional GS66508T-EVBHB Eval Board can be configured into any half bridge-based topology, including Boost and Buck modes. The Eval Board comes with a Quick Start instruction guide and YouTube video links to have the installation up and running in minutes. The Eval Board can be used in synchronous Boost or Buck conversion, as well as pulsed switching to evaluate transistor waveforms. The kit has full documentation, including Bill-of-Materials component part numbers, PCB layout and thermal management, and gate drive circuit reference design which is also useful for system engineers to use in their products.

Designed to provide electrical engineers with a complete working power stage, the evaluation board consists of two 650V, 30A GS66508T GaN FETs, half bridge gate drivers, a gate drive power supply, and heatsink. The GS66508T high power transistors are based on GaN Systems’ Island Technology and belong to its 650V family of high density devices which achieve extremely efficient power conversion with fast switching speeds of over 100 V/nsec and ultra-low thermal losses. GaN Systems says it is the only company to have developed and productised a comprehensive portfolio of GaN power transistors with voltage ratings of 100V and 650V and current ratings from 7A to 250A. Island Technology die design, combined with the extremely low inductance and thermal efficiency of GaNPX packaging, provides the company's GaN FETs with 45x improvement in switching and conduction performance over traditional silicon MOSFETs and IGBTs.

The 30A/55 mΩ GS66508T GaN power transistors are top-side cooled and feature near-chip-scale, thermally-efficient GaNPX packaging. 98.7% power conversion efficiency at 1.5kW is shown in the product documentation and can be reproduced in the owner’s lab.

The Eval Board provides footprints for output power inductors and capacitors to allow users to configure the board into desired Boost or Buck operational modes. Access to the transistor junction temperature is provided by both thermocouple pads and thermal camera imaging ports. Power input should be