A 450V Three Phase GaN IPM Achieving 99.1% Efficiency in Smallest 12mm x12mm Package for 250W Power Delivery without Heatsink

This work demonstrates a three-phase motor drive Intelligent Power Module (IPM) based on Gallium-Nitride (GaN) power transistors for major increase in efficiency and power density compared to today’s Industry’s best in class. Thanks to the superior characteristics of GaN (lower specific resistance, best-in-class figure-of-merit for switching: Qoss*RDSon, zero reverse-recovery) and intelligent gate driver design, this work reduces switching and conduction loss and eliminates reverse-recovery achieving inverter efficiency up to 99.1% while maintaining safe operation for motors. The high efficiency enables 250W power delivery without heat sink in a 65% smaller package; a 12mm*12mm quad-flat no leads (QFN) compared to state-of-the-art silicon-based implementations in > 29mm*12mm leaded packages. High level of integration enables intelligent gate driving unleashing the full potential of GaN technology achieving high efficiency and power density while keeping the GaN transistors protected at all times. This design integrates adaptive dead-time control based on in-situ power stage sensing to minimize third-quadrant conduction loss and reduce total harmonic distortion (THD) of the motor current by 2.5x compared to silicon based implementations. GaN specific challenges such as slew-rate control despite the highly non-linear capacitances are handled by package-integrated gate drivers. The technology-inherent lower short-circuit ruggedness of GaN transistors is addressed using a fast, integrated over current protection (OCP). Measurements of this work are presented and compared to existing silicon-based IPMs to quantify the benefit in terms of efficiency, power density and THD enabled by GaN.