Individual flip-flops with gated clocks for low power datapaths

Energy consumption has become one of the important factors in digital systems, because of the requirement to dissipate this energy in high-density circuits and to extend the battery life in portable systems such as devices with wireless communication capabilities. Flip-flops are one of the most energy-consuming components of digital circuits. This paper presents techniques to reduce energy consumption by individually deactivating the clock when flip-flops do not have to change their value. Flip-flop structures are proposed and selection criteria given to obtain minimum energy consumption. The structures have been evaluated using energy models and validated by switch-level simulations. For the applications considered, significant energy reductions are achieved.Peer ReviewedPostprint (published version

Low-Power, Low-Cost, & High-Performance Digital Designs : Multi-bit Signed Multiplier design using 32nm CMOS Technology

Binary multipliers are ubiquitous in digital hardware. Digital multipliers along with the adders play a major role in computing, communicating, and controlling devices. Multipliers are used majorly in the areas of digital signal and image processing, central processing unit (CPU) of the computers, high-performance and parallel scientific computing, machine learning, physical layer design of the communication equipment, etc. The predominant presence and increasing demand for low-power, low-cost, and high-performance digital hardware led to this work of developing optimized multiplier designs. Two optimized designs are proposed in this work. One is an optimized 8 x 8 Booth multiplier architecture which is implemented using 32nm CMOS technology. Synthesis (pre-layout) and post-layout results show that the delay is reduced by 24.7% and 25.6% respectively, the area is reduced by 5.5% and 15% respectively, the power consumption is reduced by 21.5% and 26.6% respectively, and the area-delay-product is reduced by 28.8% and 36.8% respectively when compared to the performance results obtained for the state-of-the-art 8 x 8 Booth multiplier designed using 32nm CMOS technology with 1.05 V supply voltage at 500 MHz input frequency. Another is a novel radix-8 structure with 3-bit grouping to reduce the number of partial products along with the effective partial product reduction schemes for 8 x 8, 16 x 16, 32 x 32, and 64 x 64 signed multipliers. Comparing the performance results of the (synthesized, post-layout) designs of sizes 32 x 32, and 64 x 64 based on the simple novel radix-8 structure with the estimated performance measurements for the optimized Booth multiplier design presented in this work, reduction in delay by (2.64%, 0.47%) and (2.74%, 18.04%) respectively, and reduction in area-delay-product by (12.12%, -5.17%) and (17.82%, 12.91%) respectively can be observed. With the use of the higher radix structure, delay, area, and power consumption can be further reduced. Appropriate adder deployment, further exploring the optimized grouping or compression strategies, and applying more low-power design techniques such as power-gating, multi-Vt MOS transistor utilization, multi-VDD domain creation, etc., help, along with the higher radix structures, realizing the more efficient multiplier designs