CP-SRAM: Charge-Pulsation SRAM Marco for Ultra-High Energy-Efficiency Computing-in-Memory

Abstract

SRAM-based computing-in-memory (SRAM-CIM) provides fast speed and good scalability with advanced process technology. However, the energy efficiency of the state-of-the-art current-domain SRAM-CIM bit-cell structure is limited and the peripheral circuitry (e.g., DAC/ADC) for high-precision is expensive. This paper proposes a charge-pulsation SRAM (CP-SRAM) structure to achieve ultra-high energy-efficiency thanks to its charge-domain mechanism. Furthermore, our proposed CP-SRAM CIM supports configurable precision (2/4/6-bit). The CP-SRAM CIM macro was designed in 180nm (with silicon verification) and 40nm (simulation) nodes. The simulation results in 40nm show that our macro can achieve energy efficiency of ∼2950Tops/W at 2-bit precision, ∼576.4 Tops/W at 4-bit precision and ∼111.7 Tops/W at 6-bit precision, respectively.