Ternary Output Binary Neural Network With Zero-Skipping for MRAM-Based Digital In-Memory Computing

This brief presents a novel ternary output binary neural network (BNN) and an MRAM-based digital in-memory computing (IMC) architecture. The proposed ternary output BNN and IMC architecture is capable of 1) improving array efficiency by using only one bit-cell for one synaptic weight, 2) no accuracy loss due to its digital nature, 3) high energy efficiency by employing a zero-skipping scheme, and 4) the use of normal memory and deep learning applications due to minimized array modification. System simulations with a two-layer perceptron show that the ternary output BNN achieves 92.12% inference accuracy measured against the MNIST dataset, while the conventional BNN shows 80.8% accuracy. In addition, when the zero-skipping scheme was employed, the energy efficiency of the proposed architecture improved from 8.13 to 58.69 TOPS/W.