Patent ID: 6144259
Filing Date: 2000-11-07
Classification: H03F

Abstract:
A circuit for controlling a low-noise amplifier including a low-noise transistor as an amplifying device, said circuit comprising:a bias voltage controller which varies a bias voltage to be applied to a gate of said transistor while said low-noise amplifier is not in operation; wherein:said bias voltage controller is comprised of first to fifth resistors, and first and second bipolar transistors;said first bipolar transistor being electrically connected at a base thereof to said first resistor, being electrically connected at an emitter thereof to a positive voltage source, and being electrically connected at a collector thereof to said second resistor, said emitter being electrically connected to said base through said third resistor;said second bipolar transistor being electrically connected at a base thereof to a node between said collector of said first bipolar transistor and said second resistor, said second bipolar transistor being grounded at an emitter thereof, and being electrically connected at a collector thereof to a negative voltage source through said fourth and fifth resistors.