Patent ID: 6642789
Filing Date: 2003-11-04
Classification: H03F

Abstract:
A single supply operational amplifier for amplifying a voltage difference between a pair of differential inputs, the amplifier comprising:a voltage source for providing a single voltage input for single supply operation; a first current source for receiving said single voltage input and providing a tail current; a differential transistor pair comprising at least a first and second transistor for receiving said tail current, said differential transistor pair configured to provide at least one of a first drain-to-source voltage, a first gate-to-source voltage, a second drain-to-source voltage and a second gate-to-source voltage; a signal averaging circuit for receiving said first and second drain-to-source voltages and providing an averaged signal; an integrated amplifier for receiving said averaged signal and providing an amplified average signal; a pair of cascoded transistors comprising at least a third and fourth cascoded transistor pair for receiving said amplified average signal, and a reference voltage source, said reference voltage source characterized by at least a positive voltage node, wherein said first transistor comprises a first CMOS transistor and said second transistor comprises a second CMOS transistor, said first CMOS transistor and second CMOS transistor characterized by a source node, a gate node, a drain node and a body node, and wherein said reference voltage source positive node is connected to said first CMOS transistor source node and said second CMOS transistor source node.