Constant-Load Energy Recovery Memory for Efficient High-Speed Operation

This paper proposes a constant-load SRAM design for highly efficient recovery of bit-line energy with a resonant power-clock supply. For each bit-line pair, the proposed SRAM includes a dummy bit-line of sufficient capacitance to ensure that the memory array presents a constant capacitive load to the power-clock, regardless of data or operation. Using a single-phase power-clock waveform, read and write operations are performed with single-cycle latency. The efficiency of the proposed SRAM has been assessed through simulations of 128 x 256 arrays with 0.25μm process parameters and a 42/58 write/non-write access pattern. Assuming lossless power-clock generation, the proposed SRAM dissipates 37% less power than its conventional counterpart at 400MHz/2.5V. When the overhead of power-clock generation is included, the proposed SRAM dissipates at least 27% less power than conventional SRAM.