Write or not: programming scheme optimization for RRAM-based neuromorphic computing

Abstract

One main fault-tolerant method for a neural network accelerator based on resistive random access memory crossbars is the programming-based method, which is also known as write-and-verify (W-V). In the basic W-V scheme, all devices in crossbars are programmed repeatedly until they are close enough to their targets, which costs huge overhead. To reduce the cost, we optimize the W-V scheme by proposing a probabilistic termination criterion on a single device and a systematic optimization method on multiple devices. Furthermore, we propose a joint algorithm that assists the novel W-V scheme by incremental retraining, which further reduces the W-V cost. Compared to the basic W-V scheme, our proposed method improves the accuracy by 0.23% for ResNet18 on CIFAR10 with only 9.7% W-V cost under variation with σ = 1.2.