Abstract
This paper presents a high-gain variable input transimpedance amplifier (TIA) for perovskite and thin-film photovoltaic sensing applications. The TIA serves as the analog front end (AFE) in the sensing system. The proposed TIA circuit employs two signal amplification stages. A cascode current mirror with a diode-connected NMOS device as an active load constitutes the first stage. The second stage is a modified two-stage op-amp circuit with its differential input devices operating in the triode region. This helps to mitigate power dissipation in the circuit. The TIA exhibits the ability to sense a wide range of input current (10 nA-20 mA) and amplifies and converts the current to a voltage of 1.12 V-1.27 V. For the specified sensing range, the TIA yields a transimpedance gain of 40 dBΩ-125 dBΩ, while consuming a peak power of 1.04 mW at a 1.8 V supply. The output current of perovskite and thin-film photovoltaics can be conveniently sensed by the proposed TIA, while the further stages of the sensing system are driven by the TIA output. The circuit is implemented in UMC180 nm technology within the Cadence Virtuoso environment.