Base-current compensation circuit to reduce input offset voltage in a bipolar operational amplifier

摘要

A bipolar operational amplifier circuit includes: a differential pair having a first transistor Q1 and a second transistor Q2; a third transistor Q6 having a first node coupled to a first node of the first transistor Q1; a fourth transistor Q9 having a first node coupled to a first node of the second transistor Q2; a fifth transistor Q8 having a first node coupled to the first transistor Q1; a sixth transistor Q11 having a first node coupled to the second transistor Q2; a current mirror 20 having a first branch coupled to a second node of the fifth transistor Q8 and a second branch coupled to a second node of the sixth transistor Q11; a seventh transistor Q27 having a base coupled to the first branch of the current mirror 20; an eighth transistor Q28 having a base coupled to the third transistor Q6; a ninth transistor Q20 having a first node coupled to a first node of the seventh transistor Q27 and a base coupled to the sixth transistor Q11; and a tenth transistor Q18 having a first node coupled to a first node of the eighth transistor Q28 and a base coupled to the sixth transistor Q11.