MOSAIC: Collaborative Compute-in-Memory µArrays for Flexible and Scalable Deep Learning

Compute-in-Memory (CiM) architectures, particularly those leveraging SRAM-based arrays, present significant opportunities for accelerating deep learning by mitigating data movement bottlenecks in traditional von Neumann systems. SRAM-based CiM offers notable advantages, including speed, seamless CMOS integration, and compatibility with existing System-on-Chip (SoC) designs. However, challenges persist, primarily stemming from analog-domain computations that necessitate analog-to-digital (A/D) and digital-to-analog (D/A) conversions, leading to reduced accuracy, increased power overhead, and rigid operational constraints. To overcome these limitations, we propose MOSAIC, a novel CiM architecture designed around three foundational principles: (1) co-designing deep learning operators for CiM such as employing multiplication-free computations and frequency-domain processing to minimize/eliminate DAC/ADC overheads; (2) leveraging a memory-immersed digitization approach that utilizes parasitic bit-lines as capacitive DACs within CiM arrays, thereby significantly reducing peripheral complexity and enhancing scalability; and (3) orchestrating inference over a network of compact CiM µArrays by dynamically interconnecting them to provide flexibility, efficiency, and minimized computational overhead for varied inference workload characteristics. Collectively with these fundamental innovations, MOSAIC addresses critical bottlenecks in accuracy, scalability, and flexibility, unlocking CiM’s full potential for efficient deep learning in embedded systems.