5,717 research outputs found
Design of Hybrid Full Adder using 6T-XOR-Cell for High Speed Processor Designs Applications
Hybrid-logic implementation is highly suitable in the design of a full adder circuit to attain high-speed low-power consumption, which helps to design n any high speed ALUs that can be used in varies processors and applicable for high speed IoT- Application. XOR/XNOR-cell, Hybrid Full Adder (HFA) are the fundamental building block to perform any arithmetic operation. In this paper, different types of high-speed, low-power 6T-XOR/XNOR-cell designs are being proposed and simulated results are presented. The proposed HFA is simulated using a cadence virtuoso environment in a 45nm technology with supply voltage as 0.8V at 1GHz. The proposed HFA consumes a power of 1.555uw, and the delay is 36.692ns. Layout designs are drawn for both 6T-XOR/XNOR-cell, and 1- bit HFA designs. XOR/XNOR-cells are designed based on the combination of normal CMOS-inverter and Pass Transistor Logic (PTL). Which is used in the design of high end device processors such as ALU that can be implemented for the IoT- design applications
Ripple clock schemes for quantum-dot cellular automata circuits
Quantum-dot cellular automata (QCA) is an emerging technology for building digital circuits at nano-scale. It is considered as an alternative to widely used complementary metal oxide semiconductor (CMOS) technology because of its key features, which include low power operation, high density and high operating frequency. Unlike conventional logic circuits in which information is transferred by electrical current, QCA operates with the help of coulomb interaction between two adjacent QCA cells. A QCA cell is a set of four quantum-dots that are placed near the corners of a square. Due to the fact that clocking provides power and control of data flow in QCA, it is considered to be the backbone of QCA operation. This thesis presents the design and simulation of a ripple clock scheme and an enhanced ripple clock scheme for QCA circuits. In the past, different clock schemes were proposed and studied which were focused on data flow in particular direction or reducing delay. This proposed thesis will study the design and simulation of new clock schemes which are more realistic for implementation, give a freedom to propagate logic in all directions, suitable for both combinational and sequential circuits and has potential to support testing and reconfiguration up to some extent. A variety of digital circuits including a 2âtoâ1 multiplexer, a 1âbit memory, an RS latch, a full adder, a 4âbit adder and a 2âtoâ4 decoder are implemented and simulated using these clock schemes. A 2âtoâ4 decoder is used to demonstrate the testing capabilities of these clock schemes. All QCA layouts are drawn and simulated in QCADesigner
Modified Level Restorers Using Current Sink and Current Source Inverter Structures for BBL-PT Full Adder
Full adder is an essential component for the design and development of all types of processors like digital signal processors (DSP), microprocessors etc. In most of these systems adder lies in the critical path that affects the overall speed of the system. So enhancing the performance of the 1-bit full adder cell is a significant goal. In this paper, we proposed two modified level restorers using current sink and current source inverter structures for branch-based logic and pass-transistor (BBL-PT) full adder [1]. In BBL-PT full adder, there lies a drawback i.e. voltage step existence that could be eliminated in the proposed logics by using the current sink inverter and current source inverter structures. The proposed full adders are compared with the two standard and well-known logic styles, i.e. conventional static CMOS logic and Complementary Pass transistor Logic (CPL), demonstrated the good delay performance. The implementation of 8-bit ripple carry adder based on proposed full adders are finally demonstrated. The CPL 8-bit RCA and as well as the proposed ones is having better delay performance than the static CMOS and BBL-PT 8-bit RCA. The performance of the proposed BBL-PT cell with current sink & current source inverter structures are examined using PSPICE and the model parameters of a 0.13 ”m CMOS process
Asynchronous Early Output Dual-Bit Full Adders Based on Homogeneous and Heterogeneous Delay-Insensitive Data Encoding
This paper presents the designs of asynchronous early output dual-bit full
adders without and with redundant logic (implicit) corresponding to homogeneous
and heterogeneous delay-insensitive data encoding. For homogeneous
delay-insensitive data encoding only dual-rail i.e. 1-of-2 code is used, and
for heterogeneous delay-insensitive data encoding 1-of-2 and 1-of-4 codes are
used. The 4-phase return-to-zero protocol is used for handshaking. To
demonstrate the merits of the proposed dual-bit full adder designs, 32-bit
ripple carry adders (RCAs) are constructed comprising dual-bit full adders. The
proposed dual-bit full adders based 32-bit RCAs incorporating redundant logic
feature reduced latency and area compared to their non-redundant counterparts
with no accompanying power penalty. In comparison with the weakly indicating
32-bit RCA constructed using homogeneously encoded dual-bit full adders
containing redundant logic, the early output 32-bit RCA comprising the proposed
homogeneously encoded dual-bit full adders with redundant logic reports
corresponding reductions in latency and area by 22.2% and 15.1% with no
associated power penalty. On the other hand, the early output 32-bit RCA
constructed using the proposed heterogeneously encoded dual-bit full adder
which incorporates redundant logic reports respective decreases in latency and
area than the weakly indicating 32-bit RCA that consists of heterogeneously
encoded dual-bit full adders with redundant logic by 21.5% and 21.3% with nil
power overhead. The simulation results obtained are based on a 32/28nm CMOS
process technology
Latency Optimized Asynchronous Early Output Ripple Carry Adder based on Delay-Insensitive Dual-Rail Data Encoding
Asynchronous circuits employing delay-insensitive codes for data
representation i.e. encoding and following a 4-phase return-to-zero protocol
for handshaking are generally robust. Depending upon whether a single
delay-insensitive code or multiple delay-insensitive code(s) are used for data
encoding, the encoding scheme is called homogeneous or heterogeneous
delay-insensitive data encoding. This article proposes a new latency optimized
early output asynchronous ripple carry adder (RCA) that utilizes single-bit
asynchronous full adders (SAFAs) and dual-bit asynchronous full adders (DAFAs)
which incorporate redundant logic and are based on the delay-insensitive
dual-rail code i.e. homogeneous data encoding, and follow a 4-phase
return-to-zero handshaking. Amongst various RCA, carry lookahead adder (CLA),
and carry select adder (CSLA) designs, which are based on homogeneous or
heterogeneous delay-insensitive data encodings which correspond to the
weak-indication or the early output timing model, the proposed early output
asynchronous RCA that incorporates SAFAs and DAFAs with redundant logic is
found to result in reduced latency for a dual-operand addition operation. In
particular, for a 32-bit asynchronous RCA, utilizing 15 stages of DAFAs and 2
stages of SAFAs leads to reduced latency. The theoretical worst-case latencies
of the different asynchronous adders were calculated by taking into account the
typical gate delays of a 32/28nm CMOS digital cell library, and a comparison is
made with their practical worst-case latencies estimated. The theoretical and
practical worst-case latencies show a close correlation....Comment: arXiv admin note: text overlap with arXiv:1704.0761
Combined Integer and Floating Point Multiplication Architecture(CIFM) for FPGAs and Its Reversible Logic Implementation
In this paper, the authors propose the idea of a combined integer and
floating point multiplier(CIFM) for FPGAs. The authors propose the replacement
of existing 18x18 dedicated multipliers in FPGAs with dedicated 24x24
multipliers designed with small 4x4 bit multipliers. It is also proposed that
for every dedicated 24x24 bit multiplier block designed with 4x4 bit
multipliers, four redundant 4x4 multiplier should be provided to enforce the
feature of self repairability (to recover from the faults). In the proposed
CIFM reconfigurability at run time is also provided resulting in low power. The
major source of motivation for providing the dedicated 24x24 bit multiplier
stems from the fact that single precision floating point multiplier requires
24x24 bit integer multiplier for mantissa multiplication. A reconfigurable,
self-repairable 24x24 bit multiplier (implemented with 4x4 bit multiply
modules) will ideally suit this purpose, making FPGAs more suitable for integer
as well floating point operations. A dedicated 4x4 bit multiplier is also
proposed in this paper. Moreover, in the recent years, reversible logic has
emerged as a promising technology having its applications in low power CMOS,
quantum computing, nanotechnology, and optical computing. It is not possible to
realize quantum computing without reversible logic. Thus, this paper also paper
provides the reversible logic implementation of the proposed CIFM. The
reversible CIFM designed and proposed here will form the basis of the
completely reversible FPGAs.Comment: Published in the proceedings of the The 49th IEEE International
Midwest Symposium on Circuits and Systems (MWSCAS 2006), Puerto Rico, August
2006. Nominated for the Student Paper Award(12 papers are nominated for
Student paper Award among all submissions
- âŠ