Patent ID: 6417728
Filing Date: 2002-07-09
Classification: H03F

Abstract:
A fully-differential, switched-capacitor, operational amplifier circuit, comprising:a first and second input terminal; an operational amplifier having a first and a second differential input, respectively receiving a first and a second differential drive voltage, symmetric to a common-mode drive voltage, a first and a second differential output, respectively supplying a first and a second differential output voltage, symmetric to an output common-mode voltage, and a bias control terminal; a first and a second feedback network, arranged respectively between said first differential output and said first input terminal, and between said second differential output and said second input terminal, and having respective intermediate nodes connected respectively to said first and second differential inputs of said operational amplifier; and a control circuit having an output connected to said bias control terminal, said control circuit detecting said output common-mode voltage, and feeding said bias control terminal with a control signal correlated to said output common-mode voltage; wherein said control circuit has a first and a second input connected directly, respectively, to said first and second differential inputs of said operational amplifier and receiving respectively said first and said second differential drive voltages.