Efficient and Robust Nonvolatile Computing-In-Memory Based on Voltage Division in 2T2R RRAM With Input-Dependent Sensing Control

Abstract

Resistive memory (RRAM) provides an ideal platform to develop embedded non-volatile computing-in-memory (nvCIM). However, it faces several critical challenges ranging from device non-idealities, large DC currents, and small signal margins. To address these issues, we propose voltage-division (VD) based computing approach and its circuit implementation in two-transistor-two-resistor (2T2R) RRAM cell arrays, which can realize energy-efficient, sign-aware, and robust deep neural network (DNN) processing. A readout technique, namely the input-dependent sensing control (IDSC) scheme, is also introduced for power saving. On this basis, a 400kb VD-based RRAM nvCIM is silicon verified. It achieves 2.54 times power reduction compared to that of the ones rely on conventional weighted-current summation (WCS) mechanism, a peak energy-efficiency of 42.6 TOPS/W and a minimum latency of 15.98 ns.