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This paper presents a low-temperature coefficient (TC) dual-reference CMOS bandgap reference (BGR) for high-performance systems working under a wide temperature range. It consists of a correction approach to eliminate the high-order inaccuracy, in which an enhanceable curvature compensation circuit is adopted to extend the operating temperature range and generate reference voltages with sub-1 ppm/°C TC. In addition, a voltage level shifter (VLS) is used to generate the latter compensated reference voltage but no need for an additional compensation circuit. The proposed BGR designed in a 0.18-µm CMOS process has a simulated TC of 0.75 ppm/°C and 0.28 ppm/°C for the first and second reference outputs, respectively, over a wide temperature range of −50 °C to 130 °C. The proposed BGR occupies a 0.0079-mm2 silicon area. The overheads make the BGR appropriate to provide reference voltages in diverse chips with high-precision systems. [ABSTRACT FROM AUTHOR]

A new 12-transistor reversible full adder (FA) is designed based on carbon-nanotube-field effect transistors (CNTFETs) with 32 nm channel length and an area of 0.2204 μm2, 1 constant input (CI), and 3 garbage outputs (GO). The FA has 3 reversible logic gates in two of its stages that are realized by the gate diffusion input (GDI) technique. In the FA, 2 Toffoli gates with 1 CI and 1 new GDI-reversible-multiplexer are used to generate Sum and C out , respectively. The multiplexer is 3*3, with two GOs, and a significant area reduction by only two transistors. The inputs of the circuit prevent the excessive increase of GOs and CIs. The Monte Carlo analysis using the HSPICE simulator indicates a better sensitivity of the FA versus fabrication with 6.45%, 1.86%, and 8.01% improvements of maximum values of power, delay, and power-delay-product (PDP). The FA is implemented in a 4-bit, 8-bit, 16-bit, and 32-bit ripple carry adder (RCA), and its superior results are seen. Under 32-bit RCA, the proposed circuit with 4956.30 fJ shows more energy savings compared to most competitors. The extracted results, the different figure of merits (FoMs), and reversibility features represent the proposed circuit as a desirable procedure for future works. [ABSTRACT FROM AUTHOR]

• Using the carbon nanotube field-effect transistors technology to design approximate arithmetic circuits. • The gate diffusion input and dynamic threshold techniques are integrated to attain efficient circuits. • The presented approximate full adders show reliable performance during image processing. • The approximate full adders applied in bioimage processing. • Fat and water can be detected in bioimages by the presented approximate cells. Two new approximate full adders (FAs) are proposed by the multiplexers (MUXs) and OR gates with the gate diffusion input (GDI) technique. The cells are named GDI-based MUX approximate FAs (GMAFAs), GMAFA1, and GMAFA2. The threshold voltage drop of the GDI-based circuits is solved by carbon nanotube field-effect transistors (CNTFETs) technology and the dynamic threshold (DT) technique. The FAs have accurate C out , approximate Sum, and a low number of transistors. They are low-power, high-speed, and energy-efficient for ripple-carry adders (RCAs). The GMAFA1 and GMAFA2 have a total area of 0.068 µm2 and 0.119 µm2, respectively, which demonstrate 27.8% and 54.55% improvement in power-delay-area-product (PDAP) in comparison with the best references. The results of error distance (ED), normalized mean error distance (NMED), power signal-to-noise ratio (PSNR), and energy-saving confirm the accuracy of the presented cells for image processing applications. [Display omitted] [ABSTRACT FROM AUTHOR]

• Using the gate diffusion input technique in a new approximate full adder. • The full adder is implemented by carbon nanotube field-effect transistors. • The dynamic threshold technique improves the full adder swing. • A new approximate subtractor implemented by the full adder. • The approximate full adder and subtractor detect brain stroke. Approximate circuits are used in fault-tolerance applications, where carbon nanotube field-effect transistor (CNTFET) technology assists to achieve high performance. In this study, a new 8-transistor approximate full adder (FA) is designed and implemented using CNTFETs based on the gate diffusion input (GDI) technique. The FA is implemented in a ripple carry adder (RCA) and a 4-bit inexact subtractor for bioimages difference detection and finally stroke recognition. The non-full-swing outputs of the presented GDI cells are obviated by the dynamic threshold (DT) technique. The presented FA consumes a power of 2.0446 µW, while its power-delay-product (PDP) is 6.4536 fJ. Also, the superior results of peak signal-to-noise ratio (PSNR), power consumption, and PDP of the proposed subtractor are 30.866 dB, 9.642 µW, and 314.907 fJ, respectively. The FA has an area of 0.161 µm2 while the 4-bit subtractor occupies 2.18 µm2. The presented circuits show efficient performance for bioelectronics integrated circuits (ICs). [Display omitted] [ABSTRACT FROM AUTHOR]

Integrated circuits (ICs) employ static and dynamic logic to improve performance and scalability. This paper presents a new circuit design approach named pseudo-dynamic logic (PDL), which shows the advantages of both static and dynamic cells. The PDL is evaluated by using a new full adder cell with 18 transistors. In the presented full adder, gate diffusion input (GDI), transmission gate (TG), and float techniques are combined, and pull-up or pull-down networks are changed into a new configuration so that the number of transistors and internal nodes will decrease. Post-layout simulations and digital image addition are performed to evaluate the real environment and practical application of the cell. Peak signal to noise ratio (PSNR), mean square error (MSE), and structural similarity index metric (SSIM) are calculated to study the cell performance in image processing. Compared to the dynamic and static circuits, the proposed PDL-based full adder cell performs better, and the results validate its effectiveness. [ABSTRACT FROM AUTHOR]

Three new approximate subtractors are presented based on the gate diffusion input (GDI) technique which benefits from the dynamic threshold (DT) technique using carbon nanotube field-effect transistors (CNTFETs) technology. Proposed-1, Proposed-2, and Proposed-3 subtractors have 10, 8, and 6 transistors with a total area of 0.289 μm2, 0.123 μm2, and 0.065 μm2, respectively. In Proposed-1 and Proposed-2, only XOR and F1 gates are used, which respectively have 2 and 4 errors. To solve the non-full-swing defects of these two circuits, only three F2-GDI gates are used in the Proposed-3, which has 4 errors. The Proposed-1 gives 0.25 as error distance (ED) while two other circuits with a lower area have an ED of 0.5. The Proposed-3 has a simple, low-power, and ground-free structure. The subtractors are implemented in an 8 to 4 non-restoring divider in four different configurations including vertical, horizontal, square, and triangular. The drivers based on Proposed-2 and Proposed-3 are the best circuits with average power-delay-product (PDP) savings of 68.16% and 57.43%, respectively. Finally, the dividers are used in the change detection of medical images, where, the proposed circuits show better circuitry performance and image quality production. [ABSTRACT FROM AUTHOR]

Different digital multipliers have resulted from various algorithms and hardware designs. This article presents a high-performance multiplier by a novel AND gate and a modified hybrid full adder (FA) cell. The AND is designed by using the pass transistor logic (PTL) technique and a speed-up transistor, while the FA is based on the transmission gate (TG). Low-power, high-speed, low power-delay-product (PDP), and high competency of both circuits for using in sophisticated structures like multipliers are confirmed by mathematical relations. The proposed 4-bit array multiplier circuit along with the pad has a 2.87 mm2 total area and is investigated under different circumstances including V DD , frequency, load capacitances, and process-voltage-temperature (PVT) variations using Monte Carlo method (MCM) by HSPICE tool and 90 nm technology. The efficiency of the multiplier in image processing applications is proved with average improvements of 12.61% and 32.045% for peak signal-to-noise ratio (PSNR) and PDP compared to state-of-the-art designs, respectively. The overall results of the multiplier approve its capability for digital signal processors (DSPs). [ABSTRACT FROM AUTHOR]