Floating Memristor Emulator Using Current Biased OTAs and Single Grounded Capacitance

The memristor emulation using Operational Transconductance Amplifiers (OTAs) has been quite popular in the last decade. Interestingly, a detailed literature survey reveals that only voltage-biased OTAs have been used so far, for the memristor emulators, which may be due to the ease of memductance realization (through just bias voltage application by employing a capacitance). But this technique has disadvantages like; mostly commercially available OTAs are current biased, voltage biasing does not provide a better range for tunability, current biasing is more stable and can be easily provided through current mirrors in large circuits. Therefore, the presented work proposes a floating memristor emulator fully based upon the current biased OTAs and upon the proper selection of parameters, it can realize a flux-controlled memductance function. The developed floating emulator uses three single output OTAs and just single grounded capacitance. The paper also describes an application example of the proposed emulator in a neuromorphic circuit to exhibit associative learning response. To verify the designed circuits, the simulations have been executed, and the results are presented. Lastly, the realization of the proposed memristor emulator using the current mode commercial IC-LM13700 is also shown and results are discussed.