  Transimpedance amplifiers (TIA) play a crucial role in various electronic
systems, especially in optical signal acquisition. However, their performance
is often hampered by saturation issues due to high input currents, leading to
prolonged recovery times. This paper addresses this challenge by introducing a
novel approach utilizing a memristive automatic gain control (AGC) to adjust
the TIA's gain and enhance its dynamic range. We replace the typical feedback
resistor of a TIA with a valence-change mechanism (VCM) memristor. This
substitution enables the TIA to adapt to a broader range of input signals,
leveraging the substantial OFF/ON resistance ratio of the memristor. This paper
also presents the reading and resetting sub-circuits essential for monitoring
and controling the memristor's state. The proposed circuit is evaluated through
SPICE simulations. Furthermore, we extend our evaluation to practical testing
using a printed circuit board (PCB) integrating the TIA and memristor. We show
a remarkable 40 dB increase in the dynamic range of our TIA memristor circuit
compared to traditional resistor-based TIAs.
