Analysis of op-amp power-supply current sensing current-mode instrumentation amplifier for biosignal acquisition system

Common biosignals are frequently recorded and used in modern clinical practice and even daily health care applications. The most important building block of such an acquisition system is the analog readout front end. Usually, an instrumentation amplifier with high CMRR and configurable gain characteristics is suitable for this application. There is a current mode instrumentation amplifier based on op amp power supply current sensing technique, which is a possible solution for designing the biosignal acquisition system. This paper makes a brief analysis of this topology and studies some features for applying to biosignals. Furthermore, a real circuit simulation analysis employing CMOS 0.35 μm technology under a 3 V power supply is conducted.