WIDEBAND VARIABLE GAIN AMPLIFIER

摘要

A wideband variable gain amplifier is provided to have low distortion and high linearity by performing stable current supply using a bleeding current. In a wideband variable gain amplifier, a transconductance conversion unit(21) controls a gain of a differential input signal by controlling the amplitude of transconductance according to a gain control signal. A load resistor stage(22,23) converts a current type differential signal outputted from the transconductance conversion unit into a voltage type differential signal. An output DC voltage comparison unit(24) detects a DC current of the differential signal converted in the load resistor stage, and sets a bias voltage by comparing the DC voltage with a reference DC voltage. A bleeding current generation unit(25) determines the intensity of a bleeding current according to a bias voltage set in the output DC voltage comparison unit, and supplies the corresponding bleeding current to the transconductance conversion unit.