A back-gate current neutralisation feedback loop for high input impedance neural front-end amplifiers

The front-end amplifier (FEA) for neural signal applications forms the critical element for signal detection and pre-processing, which determines not only the fidelity of the biosignal, but also impacts power consumption and detector size. A back-gate current neutralisation feedback technique is proposed to compensate for input leakage currents generated by low-noise amplifiers alongside signal leakage into the input bias network when in integrated circuit (IC) form. Significantly, this topology ensures the FEA maintains a high-input impedance across the wide range of manufacturing and operational variations seen in ICs.