Large signal turn-on response of the junction transistors including nonlinear effects

The large-signal transient behavior of transistors must be considered as nonlinear phenomena. In this paper, the nonlinearity of the transient behavior of transistors in the active region are considered, and the charge control method is extended to include this nonlinearity. Using a one-dimensional homogeneous-base transistor model, the current variation of small-signal time constants in the charge control concept are analyzed in terms of emitter efficiency, surface recombination, and generated field in the base region. From the results of the small signal analysis, the large-signal time constants have been defined as a function of injection ratio. From the charge control equation founded on the large-signal time constants, the rise time is calculated including the current variations of time constants and voltage variation of junction capacitance. The results of the analysis are also verified by experimental measurements.