A Ternary Based Bit Scalable, 8.80 TOPS/W CNN accelerator with Many-core Processing-in-memory Architecture with 896K synapses/mm2

A Processing-In-Memory (PIM) accelerator with ternary SRAM is proposed for low-power, large-scale deep neural network (DNN) processing. The accelerator consists of Ternary Neural Arithmetic Memory (TNAM) which is capable of bit-scalable MAC (multiply and accumulation) operation in accordance with target accuracy and power limit. An ADC less readout circuits to reduce analog-digital conversion power and a system-level variation avoidance technique utilizing features of TNAM are also proposed. A test chip with large-scale PIM is fabricated and successfully operate convolutional neural networks (CNNs) with 8.8TOPS/W and highest accuracy and area density among recent SRAM-type PIMs are obtained.