Patent ID: 6496068
Filing Date: 2002-12-17
Classification: H03F

Abstract:
An amplifier circuit comprising:a positive supply rail and a negative supply rail; a first plurality of switches stacked between said positive and negative supply rails, a biasing string comprising a plurality of RC circuits stacked between said positive and negative supply rails, one of said switches receiving an external control signal to control the conduction switches; and a feedback line from said second plurality of switches to said biasing string operable to drive said plurality of RC circuits using power from said second plurality of switches; wherein said first plurality of switches comprises a first, second, third and fourth switch arranged in a series stacked relationship between said positive and negative supply rails, said first switch receiving said control signal to control the conduction state thereof and coupled to said positive supply rail, and said fourth switch configured to operate as a current source wherein the conduction state thereof is controlled by said negative supply rail, said switches defining a first node between said first and second switch, a second node between said second and third switch, and a third node between said third and fourth switch; wherein said biasing string comprises a first, second, third and fourth parallel arrangement of said RC circuits arranged in a series stacked relationship between said positive and negative supply rails, said RC circuits dividing the potential between said positive and negative supply rails and defining a fifth node between said first and second RC circuits and a sixth node between said third and fourth RC circuits, the potential at said fifth node controlling the conduction state of said second switch, the potential at said sixth node controlling the conduction state of said third switch.