Saturation limiting system for a vertical, isolated collector PNP transistor and monolithically integrated structure thereof.

摘要

The structure of a vertical PNP transistor with isolated collector is modified by forming a P-type diffusion (10) outside the perimeter of a sinker collector diffusion (6) to form an auxiliary collector capable of detecting the injection of current toward the substrate when the integrated transistor saturates. The current gathered by said auxiliary collector is used for activating a saturation limiting circuit formed by an NPN transistor which is switched-on when said current gathered by said auxiliary collector reaches a threshold value and which in turn switches-on a PNP transistor having an emitter and a collector connected respectively to the emitter and to the base of the PNP vertical transistor with isolated collector for reducing the driving base current thereto.