Circuit-Level Techniques for Logic and Memory Blocks in Approximate Computing Systemsx

This article presents an overview of circuit-level techniques used for approximate computing (AC), including both computation and data storage units. After providing some background concept and methodology review, this article proceeds to provide a detailed review of prior art in circuit-level approximation techniques for data path and memory. The focus is on identifying key circuit-level approximation techniques that are applicable to the computational blocks in general and for both volatile and nonvolatile memory circuit technologies. Emphasis is also placed on the error metrics used to assess the output quality of approximate compute and memory units and whether the accuracy setting is dynamically reconfigurable. This article is concluded with a summary of the key distinguishing features of the reviewed prior art.