An inductive-switching loss model accounting for source inductance and switching loop inductance

It is well known that that source inductance could significantly increase turn-on and turn-off time, and therefore increase switching power loss. Also, it is well understood that switching loop inductance could reduce voltage stress during turn-on and increase voltage stress during turn-off. In this paper, a new inductive switching loss model that includes source inductance and switching loop inductance has been derived and thoroughly analyzed. The new model shows that source inductance causes a “visual gate charge”, which is equivalent to physical gate charge, when look from the driver. For high current switching conditions, the visual source charge dominates total gate charge and is the main factor for switching time. Simulations and experiments show that the model has very good accuracy.