GaN Power Switches: A Comprehensive Approach to Power Loss Estimation

Abstract

Gallium Nitride (GaN) power switches are gaining rapid acceptance due to their high efficiency operation and smaller size compared to traditional Silicon (Si) devices. To date, traditional topologies, such as boost and resonant converters, have been developed with GaN devices, and simplistic power loss models have been employed for loss prediction and thermal management design. However, high accuracy power loss analysis tools for GaN devices are missing in the literature, making thermal management design and efficiency prediction a challenge. With very small footprints and thermal capacity, accurate power loss prediction for GaN is critical and mandatory. This paper proposes a comprehensive method to predict conduction and switching losses in GaN devices. Through the use of thermal measurement, the inaccuracy of traditional electrical measurements for power losses (e.g., double-pulse test) is eliminated and a higher accuracy model is achieved. The proposed model is verified experimentally against a traditional datasheet approach and a SPICE-based double-pulse simulation. With the proposed model, a nearly four-fold reduction in error is observed across a variety of operating conditions. Ultimately, the model allows for confidence in loss prediction, allowing power converter designers to effectively design thermal management systems for maximum power density and efficiency.