Design of an energy-efficient nonvolatile lookup table circuit using active-load-localized circuitry with self-terminated writing/reading

Abstract

An energy-efficient nonvolatile lookup table (LUT) circuit, where both write and read currents are automatically terminated if desired write/read operations are completed, is proposed. The use of self-terminated writing makes it possible to cut off wasted write current by continuously monitoring voltage transitions owing to the resistance change in the storage element. In addition, wasted read current can be cut off by utilizing the voltage drop in active-load-localized circuitry as a read completion signal. In fact, the proposed 6-input LUT circuit reduces 59% of write energy and 47% read energy with only 5% of hardware overhead compared with those of a conventional circuit style under a 45 nm CMOS technology.