High-Side Driving under High-Switching Speed: Technical Challenges and Testing Methods

The current design trend of power converters focuses on increasing efficiency and power density levels in order to minimize specific costs. Through the fast switching speed of semiconductors based on the wide-band gap (WBG) technology, such as Gallium-Nitride (GaN) and Silicon Carbide (SiC), it is possible to reduce the commutation losses, thus enabling higher switching frequency operation. Due to WBG devices high voltage variation rate during commutation, the galvanic isolation of high-side driver circuitries becomes a critical issue. The majority of state-of-the-art gate drivers are not suited for such high voltage transient levels due to limitations on the signal isolation. This paper will present an overview of current driver technologies for signal isolation, along with their inherent capabilities and limitations. An analysis of existing testing schemes and standards will be performed, making a parallel to real application conditions. Afterwards, tests considering such critical issues will be performed with selected devices. Finally, new testing and validation approaches for high-side driving isolation will be proposed regarding high-switching speed devices evaluation.