RRAM-based Analog In-Memory Computing : Invited Paper

Despite resistive random-access memories (RRAMs) have the ability of analog in-memory computing and they can be utilized to accelerate some applications (e.g., neural networks), the analog-digital interface consumes considerable overhead and may even counteract the benefits brought by RRAM-based inmemory computing. In this paper, we introduce how to reduce or eliminate the overhead of the analog-digital interface in RRAM-based neural network accelerators and linear solver accelerators. In the former, we create an analog inference flow and introduce a new methodology to accelerate the entire analog flow by using resistive content-addressable memories (RCAMs). Redundant analog-to-digital conversions are eliminated. In the latter, we provide an approach to map classical iterative solvers onto RRAM-based crossbar arrays such that the hardware can get the solution in O(1) time complexity without actual iterations, and thus, intermediate analog-to-digital conversions and digital-to-analog conversions are completely eliminated. Simulation results have proven the superiorities in the performance and energy efficiency of our approaches. The accuracy problem of RRAM-based analog computing will be a future research focus.