MOS Cascode current mirror

Claim 1

An MOS current mirror including an input circuit branch and an output circuit branch, where the input circuit branch is responsive to a reference current and the output circuit branch mirrors the reference current to produce an output current substantially equal to said reference current, the input branch comprising a series connection of a plurality of four MOS transistors each MOS transistor having a gate, a source, and a drain electrode, where the drain of the first MOS transistor is responsive to said reference current and the gate of said first MOS transistor is connected to both said drain and the gate of the second MOS transistor, the gate of the third MOS transistor is connected to both the source of said first MOS transistor and the drain of said second MOS transistor, and the gate of the fourth MOS transistor is connected to both the source of said second MOS transistor and the drain of the third MOS transistor; and the output branch comprising a pair of MOS transistors each MOS transistor having a gate, a source, and a drain electrode, where the gate of a first MOS transistor of said pair of MOS transistors is connected to the source of said first MOS transistor of said input circuit branch and the gate of the remaining MOS transistor of said pair of MOS transistors is connected to the gate of said fourth MOS transistor of said input circuit branch, wherein each MOS transistor of both said input and said output circuit branches comprises a channel constant defined by its associated channel width divided by its associated channel length, wherein the channel constant of said second MOS transistor of said input circuit branch is at most one-third the value of the channel constant associated with the remaining MOS transistors, where each of the remaining MOS transistors comprises substantially identical channel constant.