In-memory Multibit Multiplication and Accumulation Based on an Automatic
Pulse Generation Circuit
Abstract
Computing in-memory technology is a promising way of solving the
“memory wall” problem when processing large-scale data,accelerating
data processing, and improving energy efficiency. However, calculations
in the analog domain are limited in terms of accuracy and sensitivity to
process, voltage, and temperature (PVT) changes. In this study, we
proposed a computing in memory multiply-and-accumulate (CIM MAC) circuit
which could generate pulses automatically and which endows the
time-domain approach with a digital character. The MAC result was
reflected by the pulse edge and converted into the final digital output
using a dual-edge counter quantization circuit, improving the accuracy
of the MAC operation and reducing the difficulty of quantization. The
performance of the proposed CIM circuit was evaluated using a 28-nm
process. It could achieve 4-bit multiplication without errors with an
energy efficiency of 40.34 to 883.37 TOPS/W.