High impedance large output voltage regulated cascode current mirror

Abstract

The voltage swing on an output conductor of a high speed, high dynamic range regulated cascode current mirror is increased by providing a first transistor (M1) of a first conductivity type having a source electrode coupled to a first reference voltage conductor (GND), a gate electrode coupled to a first bias voltage circuit (M5,I1), and a drain coupled to a first conductor (4), a second transistor (M2) of the first conductivity type having a source electrode coupled to the first conductor (4), a gate electrode coupled to a second conductor (3), and a drain electrode coupled to the output conductor (2), and a third transistor (M3) of the first conductivity type having a source electrode coupled to the first reference voltage conductor (GND) and a drain coupled to the second conductor (3). A load circuit (I.sub.2) is coupled between a second reference voltage conductor (V.sub.DD) and the second conductor (3), wherein the third transistor (M3) and the load circuit (I.sub.2) functions as a high speed amplifier (5) coupling voltage changes on the first conductor (4) to the gate electrode of the second transistor (M2). A constant voltage (V.sub.S) is applied between the first conductor (4) and the gate of the third transistor (M3). The polarity of the constant voltage V.sub.S is set to maintain a voltage of the first conductor (4) at a minimum V.sub.DS magnitude level with respect to a voltage of the first reference voltage conductor (GND).