Substrate bias for MOS integrated circuit

摘要

A charge pump circuit for generating a substrate bias for MOS/LSI integrated circuit chips is provided, preferably for P-channel integrated circuits. The charge pump circuit includes an osicllator producing a square wave which is applied to a reference circuit that is also responsive to a threshold voltage Vt monitor. The reference circuit applies to a pump diode a square wave having a level responsive to the supply and thresholds. A zero voltage drop source follower connects the square wave to the diode to avoid loading. The threshold monitor forces the square wave to a high level when the threshold is below a certain value.