Antisaturation circuit for integrated PNP transistor with intervention characteristic definable according to a preset function

摘要

Described is an antisaturation circuit for an integrated PNP transistor characterized by a comparator circuit comprising two transistors and a current generator whose output current corresponds to a pre-established function, e.g., an exponential function, of the emitter current of said transistor. The changing of state of the comparator circuit, as determined by said pre-established function of said current generator, is determined by the drop of the VCE voltage of the transistor below a preset minimum value, with a portion of the conduction current of one of the two transistors of the comparator circuit utilized for increasing the forced beta of the transistor. This limits the degree of its saturation, as well as the leakage current toward the substrate.