Low-power SRAM design is crucial since it takes a large fraction of total power and die area in high-performance processors. Reducing voltage swing of the bit-line is an effective way to save the power dissipation in write cycles. Voltage swing reduction of bit-lines is, however, limited due to possible write-failures. We propose a new low-power SRAM using bit-line Charge Recycling (CR-SRAM) for the write operation. In the proposed write scheme, differential voltage swing of a bit-line is obtained by recycled charge from its adjacent bit-line capacitance, instead of the power line. Applying such a charge recycling technique to the bit-line significantly reduces write power. A test chip with 32 Kbits (256 rows 128 columns) is fabricated and measured in 0.13 m CMOS to demonstrate operation of the proposed SRAM. Measurement results show 88% reduction in total power during write cycles compared to the conventional SRAM (CON-SRAM) at VDD = 1.5 V and f = 100 MHz.
Charge transfer, Electric potential, Energy dissipation, Program processors, Static random access storage
Date of this Version
IEEE Journal of Solid-State Circuits 43,2 (2008) 446-458;
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