A Time-Domain Computing-In-Memory Micro using Ring Oscillator

This paper proposes a novel time-domain computing-in-memory core that implements XNOR-and-accumulate (XAC) of XNOR network in 8T SRAM cell. This new technique uses an inverter-based ring oscillator to generate periodic waves whose period represents the accumulation result of the input XNOR values. The circuit is built and simulated using PTM16_HP 16nm CMOS model with a 0.7V power supply. The results show correct functionality, a large signal margin and 463 TOPS/W efficiency. With further exploration, the time-domain computation could be a new candidate for in-memory computing since it has its own superiorities in comparison to mixed-signal or digital methods.