Conventional logic and memory devices are built out of deterministic units such as transistors, or magnets with energy barriers in excess of 40-60 kT. We show that stochastic units, p-bits, can be interconnected to create robust correlations that implement Boolean functions with impressive accuracy, comparable to standard circuits. Also they are invertible, a unique property that is absent in digital circuits. When operated in the direct mode, the input is clamped, and the network provides the correct output. In the inverted mode, the output is clamped, and the network fluctuates among possible inputs consistent with that output. We present an implementation of an invertible gate to bring out the key role of a three-terminal building block to enable the construction of correlated p-bit networks. The results for this implementation agree well with those from a universal model, showing that p-bits need not be magnet-based: any three-terminal tunable random bit generator should be suitable. We present an algorithm for designing a Boltzmann machine (BM) with symmetric connections that implements a given truth table. We then show how BM Full Adders can be interconnected in a partially directed manner to implement large operations such as 32-bit addition. Hundreds of p-bits get precisely correlated such that the correct answer out of 2^33 possibilities can be extracted by looking at the mode of a number of time samples. With perfect directivity a small number of samples is enough, while for less directed connections more samples are needed, but even in the former case invertibility is largely preserved. This combination of accuracy and invertibility is enabled by the hybrid design that uses bidirectional units to construct circuits with partially directed connections. We establish this result with examples including a 4-bit multiplier which in inverted mode functions as a factorizer.

Stochastic p-bits for Invertible Logic

https://cyberleninka.org/article/n/7523.pdf

Modified Gate Diffusion Input Technique: A New Technique for Enhancing Performance in Full Adder Circuits

Adders are one of the most widely digital components in the digital integrated circuit design and are the necessary part of Digital Signal Processing (DSP) applications. With the advances in technology, researchers have tried and are trying to design adders which offer either high speed, low power consumption, less area or the combination of them. In this paper, the design of various adders such as Ripple Carry Adder (RCA), Carry Skip Adder (CSkA), Carry Increment Adder (CIA), Carry Look Ahead Adder (CLaA), Carry Save Adder (CSA), Carry Select Adder (CSlA), Carry Bypass Adder (CByA) are discussed and the performance parameters of adders such as area and delay are determined and compared. Various adders are designed using Verilog HDL. Then, they are simulated and synthesized using Xilinx ISE 13.2 for Virtex-6 family device with speed grade -2.

Design and Performance Analysis of Various Adders using Verilog

Addition is one of the essential operations in Digital Signal Processing (DSP) applications which includes Fast Fourier Transform (FFT), Digital filters, multipliers etc. With the advancements in technology, research is still going on to design a adder that performs addition in flash of time. One of such high speed adder is Carry Save Adder (CSA). In this paper we have designed High Speed Carry Save Adder (CSA) using Carry Look ahead adder in the final stage instead of using conventional ripple carry adder [1] so that speed increases by 27.5%.

Design of high speed carry save adder using carry lookahead adder

Reliability to soft errors is an increasingly important issue as technology continues to shrink. In this paper, we show that applications exhibit different reliability characteristics on big, high-performance cores versus small, power-efficient cores, and that there is significant opportunity to improve system reliability through reliability-aware scheduling on heterogeneous multicore processors. We monitor the reliability characteristics of all running applications, and dynamically schedule applications to the different core types in a heterogeneous multicore to maximize system reliability. Reliability-aware scheduling improves reliability by 25.4% on average (and up to 60.2%) compared to performance-optimized scheduling on a heterogeneous multicore processor with two big cores and two small cores, while de-grading performance by 6.3% only. We also introduce a novel system-level reliability metric for multiprogram workloads on (heterogeneous) multicores. We further show that our reliability-aware scheduler is robust across core count, number of big and small cores, and their frequency settings. The hardware cost in support of our reliability-aware scheduler is limited to 296 bytes per core.

Reliability-Aware Scheduling on Heterogeneous Multicore Processors

Adders form an almost obligatory component of every contemporary integrated circuit. The prerequisite of the adder is that it is primarily fast and secondarily efficient in terms of power consumption and chip area. This paper presents the pertinent choice for selecting the adder topology with the tradeoff between delay, power consumption and area. The adder topology used in this work are ripple carry adder, carry lookahead adder, carry skip adder, carry select adder, carry increment adder, carry save adder and carry bypass adder. The module functionality and performance issues like area, power dissipation and propagation delay are analyzed at 0.12 µm 6metal layer CMOS technology using microwind tool.

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Sharon Paul

Papers

Area, Delay And Power Comparison Of Adder Topologies