Patent ID: 7253686
Filing Date: 2007-08-07
Classification: H03F

Abstract:
1. An amplifier that processes signals from an amplifier input port to an amplifier output port, comprising: a first differential pair of transistors that define said amplifier input port and a first differential port and are coupled to steer a first tail current across said first differential port in response to signals at said amplifier input port; a second differential pair of transistors that define a second differential port for receiving signals from said first differential port and that define said amplifier output port and are coupled to steer a second tail current across said amplifier output port in response to signals at said second differential port; and at least one feedback circuit arranged to mirror and adjust at least one of said first and second tail currents in response to signals from at least one of said second differential port and said amplifier output port; wherein said feedback circuit includes: a current source; a reference generator that provides a reference signal; a feedback amplifier configured to mirror said first tail current from said current source to said first differential pair and provide an error signal to adjust said first tail current in response to a difference between said reference signal and a common-mode signal at said second differential port.