Switching Loss Characterization of GaN-based Buck Converter under Different Substrate Biases

Switching loss of GaN-based synchronous buck converter under different substrate biases are characterized and analyzed by experiment. Switching loss of high side GaN power device increases with positive substrate bias but decreases with increasing magnitude of negative substrate bias. Gate charge (Qg), which plays a dominant role in determining the switching loss, has been studied subjected to different substrate biases. The correlation between distinct buffer traps and Qg change has been identified in order to mitigate/reduce the switching loss of a synchronous buck converter by optimizing its substrate biasing.