A low voltage, high bandwidth, enhanced transconductance, source follower
circuit constructed from MOS FET devices, which operates in a class AB
mode. The drain current of the source follower is sensed with a folded
cascode device. The sensed current is multiplied by a common source
device of same type (NMOS or PMOS) as the source follower, and directed
to the output load. Over limit current load at the source follower drain
is sensed by a common source device of the opposite type (NMOS or PMOS),
which also supplies the necessary extra current to the output load. This
allows the device to supply significantly more than the quiescent current
in both sourcing and sinking the output. Average power consumption for
driving a given load is significantly reduced, while maintaining the
large bandwidth of traditional source follower designs, and the
capability for use in either voltage regulators or in a current conveyor.