TimeFloats: Train-in-Memory with Time-Domain Floating-Point Scalar Products

Abstract

In this work, we propose "TimeFloats," an efficient train-in-memory architecture that performs 8-bit floating-point scalar product operations in the time domain. While building on the compute-in-memory paradigm's integrated storage and inferential computations, TimeFloats additionally enables floating-point computations, thus facilitating DNN training within the same memory structures. Traditional compute-in-memory approaches with conventional ADCs and DACs face challenges such as higher power consumption and increased design complexity, especially at advanced CMOS nodes. In contrast, TimeFloats leverages time-domain signal processing to avoid conventional domain converters. It operates predominantly with digital building blocks, reducing power consumption and noise sensitivity while enabling high-resolution computations and easier integration with conventional digital circuits. Our simulation results demonstrate an energy efficiency of 22.1 TOPS/W while evaluating the design on 15 nm CMOS technology.