Automatic gain control electronic circuit with dual slope for an amplifier

An electronic circuit for the automatic gain control of an input amplifier, the electronic circuit including a non-linear amplifier-comparator in an automatic gain control loop, for comparing a first reference signal to a second signal relating to the amplitude level of an output signal of the input amplifier, the non-linear amplifier-comparator allowing the dynamic, analogue, dual slope adaptation of the input amplifier gain,

• wherein the non-linear amplifier-comparator includes a first branch with a first input transistor having a first type of conductivity, arranged in series between a first polarisation transistor having a first type of conductivity and a first diode-connected transistor having a second type of conductivity of a current mirror, between a negative terminal and a positive terminal of a supply voltage source, a gate or a base of the first input transistor being capable of receiving the first signal or the second signal,
• wherein the non-linear amplifier-comparator includes a second branch with a second input transistor having a first type of conductivity, arranged in series between a second polarisation transistor having a first type of conductivity and a second transistor having a second type of conductivity of the current mirror, between the negative terminal and the positive terminal of the supply voltage source, a gate or a base of the second polarisation transistor being connected to a gate or a base of the first polarisation transistor to be powered by a polarisation voltage, a gate or a base of the second transistor of the current mirror being connected to a gate or a base of the first diode-connected transistor of the current mirror, and a gate or a base of the second input transistor being capable of receiving the second reference signal or the first signal inversely to the first input transistor, and
• in that the non-linear amplifier-comparator includes at least one non-linear transconductance element connecting the source or the emitter of the first input transistor to the source or the emitter of the second input transistor and capable of allowing the amplifier-comparator to output via the drain or the collector of the second input transistor, a dual slope gain adjustment signal, if the deviation between the first input signal and the second input signal is greater or smaller than a defined threshold.