Patent ID: 6456162
Filing Date: 2002-09-24
Classification: H03F

Abstract:
An operational amplifier comprising:an input stage including first and second input arms forming a differential input; a level-transforming stage including a first transforming arm comprising a first bipolar transistor and a second transforming arm comprising a second bipolar transistor, said first and second bipolar transistors each comprising a base, collector and emitter, said first bipolar transistor is connected to the first input arm and said second bipolar transistor is connected to the second input arm, the base of said first bipolar transistor is connected to the base of said second bipolar transistor; a bypass arm connected between the collector and the base of said first bipolar transistor; a centering arm comprising a centering transistor connected in series with a centering resistor, said centering transistor comprising a base connected to the base of said first and second bipolar transistors to control a current conducting in the bypass arm; and at least one gain stage connected to said second bipolar transistor.