MODELING BUFFER LAYER IGBTS FOR CIRCUIT SIMULATION

The dynamic behavior of commercially available buffer layer IGBT's is described. It is shown that buffer layer IGBT's become much faster at high voltages than nonbuffer layer IGBT's with similar low voltage characteristics. Because the fall times specified in manufacturers' data sheets do not reflect the voltage dependence of switching speed, a new method of selecting devices for different circuit applications is suggested. A buffer layer IGBT model is developed and implemented into the Saber circuit simulator, and a procedure is developed to extract the model parameters for buffer layer IGBT's. It is shown that the new buffer layer IGBT model can be used to describe the dynamic behavior and power dissipation of buffer layer IGBT's in user-defined application circuits, The results of the buffer layer IGBT model are verified using commercially available IGBT's.