Conditional and Multi-Level WRITE Operations on Current-Controlled Memristive Devices for Neuromorphic Applications

The analog response of memristive devices makes them suitable for various applications, such as multilevel memory and neuromorphic computing. When the devices are voltage-driven, resistive switching is associated with voltage thresholds, representing the minimum required voltage to trigger a SET or RESET. Most simulation models correspond to voltage-controlled memristive devices, and multilevel tuning in such cases can be achieved via a controlled voltage-driven SET process. However, when current drivers are used instead of voltage drivers, a proper assessment of device performance should also consider models of current-controlled devices whose response adheres to current thresholds. To this end, here we provide both the voltage- and the current-controlled version of a behavioral model of memristive devices in a readily available netlist for simulation in LTSpice. We present simulation results using both model versions and show that, to achieve multilevel tuning of current-controlled devices when current-driven, a current divider circuit can enable a controlled RESET process. Finally, we provide experimental results for the controlled switching response of Self-Directed Channel (SDC) bipolar memristive devices by Knowm Inc. Overall, we demonstrate the feasibility of conditional and multilevel switching of current-controlled memristive devices, towards the design of current-based multilevel drivers and in-memory logic based on the conditional switching response triggered via current stimuli.