Amplification interface, and corresponding measurement system and method for operating an amplification interface

An amplification-interface circuit of a sensor circuit formed by a first field effect transistor (FET) and a second FET arranged in a differential pair to supply a differential current to a first node and a second node, comprising:

• a differential-current reading circuit including a first input terminal connected to said second node and a second input terminal connected to said first node, said differential-current reading circuit comprising a continuous-time sigma-delta conversion circuit including at least one integrator-and-adder module generating an output signal that is coupled to an input of a multilevel quantizer circuit configured to output a multilevel quantized signal;
• wherein said at least one integrator-and-adder module comprises:
• a differential current-integrator circuit configured to output a voltage proportional to an integral of a difference between currents received at said first and second input terminals;
• and
• a digital-to-analog converter, driven by a respective reference current generated by a reference current generator, configured to receive and convert said multilevel quantized signal into a differential analog feedback signal;
• wherein said differential current-integrator circuit is configured to add said differential analog feedback signal to said currents received at said first input terminal and said second input terminal.