Patent ID: 6046642
Filing Date: 2000-04-04
Classification: H03F

Abstract:
An amplifier with active bias compensation, comprising:a first amplification element having a bias terminal, and a current supply terminal coupled to a first voltage supply conductor via a sensing resistor;an active bias compensation circuit having a first input and a second input coupled across the sensing resistor for sensing a quiescent current in the first amplification element, and an output coupled to the bias terminal of the first amplification element, wherein the active bias compensation circuit includes:a first transistor having a control electrode coupled to the first input of the active bias compensation circuit, a first current conducting electrode, and a second current conducting electrode;a second transistor having a control electrode coupled for receiving a reference voltage, a first current conducting electrode coupled to the first current conducting electrode of the first transistor, and a second current conducting electrode coupled to the output of the active bias compensation circuit;a first resistor having a first electrode coupled to a first voltage supply conductor and a second electrode coupled to the first current conducting electrode of the first transistor; anda second resistor having a first electrode coupled to the second current conducting electrode of the first transistor and a second electrode coupled to the second input of the active bias compensation circuit; anda second amplification element having a quiescent current tracking the quiescent current in the first amplification element.