Electronic circuit having a unit for attenuating at least one input signal of an amplifier in an automatic gain control loop

摘要

The circuit (1) has an attenuation unit (10) including a comparison unit for comparing an adaptation signal (VAGC) to a reference signal (VREF) and for supplying an attenuation current, whose intensity is a function of difference between the adaptation and reference signals. A diode-connected replica transistor (M2) controls a shunt transistor (M1) having a conductivity type, which defines a shunt resistance connected to an input of an input amplifier (2) e.g. LNA amplifier. A resistive value of the input depends on the intensity of the current passing through the replica transistor.