VARIABLE-GAIN DIFFERENTIAL INPUT AND OUTPUT AMPLIFIER

摘要

The invention concerns a variable-gain differential input and output amplifier comprising an attenuation network (AT1, AT2), receiving an input voltage (V1in-V2in) and supplying on several outputs (O1i, O2i) voltages each of which is equal to the attenuated input voltage; differential transconductance elements (G1i, G2i) each having a first input connected to an output (O1i, O2i) of the attenuation network, and producing first (l<1+>) and second (l<2>+) positive currents and first (1<1->) and second (1<2->) negative currents, a set of current sources (10) for controlling transconductance of each transconductance element based on an analog control signal (Vcom); and an output block (26) converting the first and second input currents into a differential output voltage (V1out-V2out) and supplying to the second input of each transconductance element a feedback voltage dependent on the output voltage.