Patent ID: 7420412

Claim:
An integrated circuit comprising: a first circuit branch, coupled between a first node and a second node, comprising a first amplifier stage and a second amplifier stage, coupled in series; a second circuit branch, coupled between the second node and a third node, comprising a first impedance matching unit and a third amplifier stage, coupled in series; and a third circuit branch, coupled between the second node and the third node, comprising an impedance transformer unit, wherein during a first mode of operation of the circuit, the third amplifier stage is in an off state, consuming less power than in an on state, and a signal output from the first amplifier stage passes through the second amplifier stage and substantially through the third circuit branch, and during a second mode of operation of the amplifier circuit, the third amplifier stage is in the on state and the signal output from the first amplifier stage passes through the second amplifier stage and substantially through the second circuit branch.