Patent ID: 7109697

Claim:
An operational amplifier having temperature-compensated offset correction, comprising: an operational amplifier circuit, comprising a first input field effect transistor (FET) having a gate connected to receive a first input signal, and a second input FET having a gate connected to receive a second input signal, the first and the second input FETs being connected together at a first connection at one of their source and drain and receiving a first bias current at said connection, and being connected to respective sides of a first current mirror by the other of their source and drain; a correction amplifier circuit, comprising a first correction FET having a gate, and a second correction FET having a gate, the first and the second correction FETs being connected together at a second connection at one of their source and drain and receiving a second bias current at said connection, and being connected to respective sides of a second current mirror by the other of their source and drain; a resistor arranged to have a fixed voltage provided across it, one terminal of the resistor being connected to the gate of the first correction FET and the other terminal of the resistor being connected to the gate of the second correction FET; a first bias FET connected to conduct a current from the second correction FET that does not flow through the second current mirror; a second bias FET connected in current mirror configuration with the first bias FET to form a third current mirror, and configured to mirror and scale the current through the first bias FET to a selected one of the first input FET and the second input FET.