Patent ID: 7411453

Claim:
Amplifier circuitry comprising: (a) first and second pairs of differentially coupled input transistors, each transistor having a first electrode, a second electrode, and a control electrode, a differential input voltage being coupled between the control electrodes of the first pair and also being coupled between the control electrodes of the second pair, the second electrodes of the first and second pairs of differentially coupled input transistors being coupled to a folded cascode stage; (b) first current mirror circuitry for generating a reference current; (c) second current mirror circuitry receiving the reference current and producing a mirrored reference current; (d) current steering circuitry operative to steer the mirrored reference current as a first tail current through the first electrodes of the transistors of the first pair when a common mode input voltage of the amplifier circuitry exceeds a first reference voltage; (e) third current mirror circuitry receiving and amplifying a first portion of the mirrored reference current from the current steering circuitry when the common mode voltage is less than the first reference voltage to produce a second tail current through the first electrodes of the transistors of the second differentially coupled pair; and (f) current feedback circuitry receiving a second portion of the mirrored reference current and summing the second portion with the reference current at an output of the first current mirror circuitry so as to reduce the mirrored reference current when the common mode voltage is less than the first reference voltage.