A model for turn-off in bipolar transistors

A new model is proposed that accounts for the dynamics of charge removal for a device which is initially in deep or "classical" saturation. An experimental check of the model shows good agreement with measured values of storage time and VBE(t) and vCE(t) waveforms during the turn-off interval. An additional feature of the model is the possibility of introducing the action of circuit elements in an interactive manner so that device behavior in an actual switching circuit can be predicted. Finally, the possibility of predicting the onset of second breakdown is discussed.