DynaPlasia: An eDRAM In-Memory Computing-Based Reconfigurable Spatial Accelerator With Triple-Mode Cell

Abstract

This article presents DynaPlasia, a reconfigurable eDRAM-based in-memory computing (IMC) processor with a novel triple-mode cell. It enables higher system-level performance and efficiency in a resource-limited environment. DynaPlasia proposes five key features that can enhance the energy efficiency and area efficiency of the IMC accelerator: 1) dynamic reconfigurable core architecture (DRECA), which dynamically reconfigures the effective IMC macro size according to DNN workloads; 2) the triple-mode cell is reconfigured as IMC PE, unit DAC, and unit cell to optimize system resource utilization adaptively; 3) hierarchical in-memory ADC (Hi-ADC) reduces ADC area overhead with tripe-mode cell and saves power with the hierarchical operation; 4) signed-input signed-weight (SISW) IMC reduces logic switching activity with signed magnitude representation; and 5) leakage-tolerant computing (LTC) to enable high-density cell design. The DynaPlasia is fabricated in 28-nm CMOS technology and occupies a 20.25-mm(2) die area with 9.6-Mb cell capacity. Its measured system peak throughput is 19.5 TOPS (4 b-5 b), and system peak efficiency is 56.0 TOPS/W (4 b-5 b). Even with the ResNet50 @ ImageNet dataset, system efficiency is 29.5 TOPS/W which is 2.5 $\times$ higher than the previous state-of-the-art.