Patent attributes
Methods and devices for a wide-swing cascode current mirror with low headroom voltage and high output impedance are presented. An input leg of the current mirror includes a composite transistor in series connection with an intrinsic transistor. The composite transistor includes two series-connected regular transistors with respective sizes that are twice the size of the intrinsic transistor. An output leg of the current mirror includes a regular transistor in series connection with an intrinsic transistor. A gate voltage of the composite transistor, provided at a node that is common to gates of the two series-connected regular transistors, self-establishes when a reference current flows through the input leg. The self-established gate voltage is used to bias the regular transistor of the output leg. Biasing voltages to gates of the intrinsic transistors is provided by an intermediate node that provides the series connection of the regular transistors of the composite transistor.
