A low-power charge-recycling ROM architecture

Abstract

This paper describes a newly proposed low-power charge-recycling read-only memory (CR-ROM) architecture. The CR-ROM reduces the power consumption in bit lines, word lines, and precharge lines by recycling the previously used charge. In the proposed CR-ROM, bit-line swing voltage is lowered by the charge recycling between bit lines. When N bit lines recycle their charges, the swing voltage and the power of the bit lines become 1/N and 1/N-2 compared to the conventional ROMs, respectively. As the number of N increases, the power saving in bit lines becomes salient. Also, power consumption in word lines and precharge lines can be reduced theoretically to half by the proposed charge-recycling techniques. The simulation results show that the CR-ROM consumes 60%similar to85% of the conventional low-power ROMs with 1 K x 32 b. A CR-ROM with 32 kb was implemented in a 0.35-mum CMOS process. The power dissipation is 6.60 mW at 100 MHz with 3.3 V and the maximum operating clock frequency is 150 MHz.