TEMPERATURE-INDEPENDENT AMPLIFIER OFFSET TRIM CIRCUIT

摘要

An operational amplifier having temperature compensated offset correction. First and second FETs have their gates connected to receive input signals and are connected together to receive a first bias current and to respective sides of a first current mirror. A correction amplifier has first and second correction FETs (MP1, MP2) that are connected together to receive a second bias current, and to respective sides of a second current mirror (MN 1, MN2). A resistor (R2) is arranged to have a fixed voltage provided across it, one terminal of the resistor being connected to the gate of the first correction FET1 the other terminal being connected to the gate of the second correction FET. A bias circuit is also provided to conduct an "extra" current from the second correction FET that is blocked by the current mirror action from flowing through the second current mirror and to form a third current mirror.