Patent ID: 6573791
Filing Date: 2003-06-03
Classification: H03F

Abstract:
A compensated three stage amplifier comprising:a first, a second and a third cascaded gain stage for amplifying an input signal and providing an output signal in dependence thereupon, each gain stage comprising an input port and an output port, wherein the input signal is received at the input port of the first gain stage and wherein the output signal is provided by the output port of the third gain stage; a first feedback loop provided from the output port of the third gain stage to the output port of the second gain stage; a second feedback loop provided from the output port of the third gain stage to the output port of the first gain stage; a first feed forward transconductance stage extending from the input port of the first gain stage to the output port of the third gain stage, wherein the first feed forward transconductance stage is for canceling one of the zeros introduced by the first and second feedback loop in the transfer function of the three stage amplifier; a second feed forward transconductance stage extending from the output port of the first gain stage to the output port of the third gain stage, wherein the second feed forward transconductance stage is for canceling another one of the zeros introduced by the first and second feedback loop in the transfer function; and, a third feed forward transconductance stage extending from the input port of the first gain stage to the output port of the second gain stage, wherein the third feed forward transconductance stage is for canceling one of two non-dominant poles in the transfer function resulting in a transfer function of the three stage amplifier having only two poles.