Universal Adaptive Biasing Principle for Micropower Amplifiers

An adaptive biasing principle for differential stages is described according to which the tail current is made input-signal dependent through negative-feedback control. The control is based on a criterion which results in an optimal combination of low power consumption and high slewrate capability. Distortion properties are not degraded. The required circuitry is simple. The technique is universal in the sense that it can be applied both to bipolar and CMOS circuits; in weak as well as in strong inversion.