Low Voltage Floating Gate MOS Transistor Based Four-Quadrant Multiplier

This paper presents a four-quadrant multiplier based on square-law characteristic of floating gate MOSFET (FGMOS) in saturation region. The proposed circuit uses square-difference identity and the differential voltage squarer proposed by Gupta et al. to implement the multiplication function. The proposed multiplier employs eight FGMOS transistors and two resistors only. The FGMOS implementation of the multiplier allows low voltage operation, reduced power consumption and minimum transistor count. The second order effects caused due to mobility degradation, component mismatch and temperature variations are discussed. Performance of the proposed circuit is verified at ±0.75 V in TSMC 0.18 µm CMOS, BSIM3 and Level 49 technology by using Cadence Spectre simulator

Design of a CMOS closed-loop system with applications to bio-impedance measurements

This paper proposes a method for impedance measurements based on a closed-loop implementation of CMOS circuits. The proposed system has been conceived for alternate current excited systems, performing simultaneously driving and measuring functions, thanks to feedback. The system delivers magnitude and phase signals independently, which can be optimized separately, and can be applied to any kind of load (resistive and capacitive). Design specifications for CMOS circuit blocks and trade-offs for system accuracy and loop stability have been derived. Electrical simulation results obtained for several loads agree with the theory, enabling the proposed method to any impedance measurement problem, in special, to bio-setups including electrodes.Ministerio de Ciencia e Innovación TEC2007-6807

Operational transconductance amplifier-based nonlinear function syntheses

It is shown that the operational transconductance amplifier, as the active element in basic building blocks, can be efficiently used for programmable nonlinear continuous-time function synthesis. Two efficient nonlinear function synthesis approaches are presented. The first approach is a rational approximation, and the second is a piecewise-linear approach. Test circuits have been fabricated using a 3- mu m p-well CMOS process. The flexibility of the designed and tested circuits was confirme

Analog VLSI neural network integrated circuits

Two analog very large scale integration (VLSI) vector matrix multiplier integrated circuit chips were designed, fabricated, and partially tested. They can perform both vector-matrix and matrix-matrix multiplication operations at high speeds. The 32 by 32 vector-matrix multiplier chip and the 128 by 64 vector-matrix multiplier chip were designed to perform 300 million and 3 billion multiplications per second, respectively. An additional circuit that has been developed is a continuous-time adaptive learning circuit. The performance achieved thus far for this circuit is an adaptivity of 28 dB at 300 KHz and 11 dB at 15 MHz. This circuit has demonstrated greater than two orders of magnitude higher frequency of operation than any previous adaptive learning circuit

1.5-V CMOS Current Multiplier/Divider

A circuit technique for designing a compact low-voltage current-mode multiplier/divider circuit in CMOS technology is presented.  It is based on the use of a compact current quadratic cell able to operate at low supply voltage.  The proposed circuit is designed and simulated for implementing in TSMC 0.25-m CMOS technology with a single supply voltage of 1.5 V.  Simulation results using PSPICE, accurately agreement with theoretical ones, have been provided, and also demonstrate a maximum linearity error of 1.5%, a THD less than 2% at 100 MHz, a total power consumption of 508 W, and -3dB small-signal frequency of about 245 MHz

Low power CMOS analog multipliers.

CMOS analog multiplier is a very important building block and programming element in analog signal processing. Although high-performance multipliers using bipolar transistors have been available for 40 years, CMOS multiplier implementation is still a challenging subject especially for low-power and low-noise circuit design. Since the supply voltage is normally fixed for analog multiplier structures, we use the total current to represent the power dissipation. Our basic idea for low power design of analog multipliers is to fit most of the transistors into the linear region, while at the same time keeping the drain-to-source voltage as low as possible to decease the drain current. And also, we use PMOS transistors for the devices working in the saturation region to further decrease the drain current and improve the linearity performance. Two low power CMOS analog multiplier designs have been proposed in this thesis. We gave detailed performance analysis and some design considerations for these structures. Cadence Hspice simulation verified our analysis. To ensure a fair comparison, we also simulated the performance of a previous multiplier structure, which was considered to be one of the best multiplier structures with low power and low noise performance. Extensive experiments and comparison for these structures show that the proposed CMOS analog multipliers have much less power dissipation than that of previous structures, while at the same time, satisfying other performance requirements. The proposed analog multipliers would be good choices in the applications where low power dissipation is an important consideration.Dept. of Electrical and Computer Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .L5. Source: Masters Abstracts International, Volume: 43-01, page: 0280. Adviser: Chunhong Chen. Thesis (M.A.Sc.)--University of Windsor (Canada), 2004

Design Of A Current Conveyor Analogue Multiplier For Energy Meter Using 0.35 Μm Mimos Cmos Technology

Analogue VLSI circuits are essential in many real-time signal processing applications as naturally occurring signals are analogue. The four-quadrant analogue multiplier is a key building block in analogue signal processing circuits. It is used to construct circuits like the modulator and waveform generator. The ideal output (Vout) of a multiplier is related to the inputs by Vout = KmVXVY, where Km is the multiplier gain with units of V-1, and VX and VY are input voltages. In reality, imperfections exist in the multiplier gain, resulting in offsets and nonlinearities. Important parameters such as power dissipation, supply voltage, input dynamic range, bandwidth, total harmonic distortion (THD) and linearity are used to assess the performance of an analogue multiplier. Nowadays both digital and analogue systems are routinely integrated onto single chips. Digital circuits commonly use low-voltage supply and employ techniques to reduce power consumption. Mixed analogue-digital circuits must be designed to operate in a low-voltage, low-power environment. Conventional analogue multipliers designed with low supply voltage suffer from performance trade-offs, resulting in low bandwidth and low dynamic range because the design of analogue circuits is a trade-off of various performance parameters such as power dissipation, supply voltage, gain, linearity and noise. The objective of this research is to design a low-voltage, low-power CMOS analogue multiplier that will address the above problems. The multiplier is designed in a modified bridged-triode scheme (MBTS) and uses current conveyors. As all analogue circuits can be decomposed into several sub-circuits, the performance of these sub-circuits decides the characteristics of the resultant circuit structure. The proposed circuit makes use of the current conveyor’s many special features, such as high output impedance and large bandwidth, to construct a low-voltage fourquadrant multiplier. The analogue multiplier designed in this research operates with a supply voltage of ±1V. The total harmonic distortion obtained from this multiplier is less than two percent, the input operating swing is up to 1Vpp, and the bandwidth achieved is more than 100MHz. It is designed using a 0.35μm technology from the Malaysian Institute of Microelectronics (MIMOS). In addition, an RMS-to-DC converter is designed using the same low-voltage design technique used for designing the adaptively-biased low-voltage current mirror (ABLVCM). Then an energy meter is designed using this analogue multiplier and the RMS-to-DC converter

Attenuated total reflection enhanced photoejection from cathodes Final report

Optical equations governing interaction between radiation and interface of two media using metallic cathode

Can deep-sub-micron device noise be used as the basis for probabilistic neural computation?

This thesis explores the potential of probabilistic neural architectures for computation with future nanoscale Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). In particular, the performance of a Continuous Restricted Boltzmann Machine {CRBM) implemented with generated noise of Random Telegraph Signal (RTS) and 1/ f form has been studied with reference to the 'typical' Gaussian implementation. In this study, a time domain RTS based noise analysis capability has been developed based upon future nanoscale MOSFETs, to represent the effect of nanoscale MOSFET noise on circuit implementation in particular the synaptic analogue multiplier which is subsequently used to implement stochastic behaviour of the CRBM. The result of this thesis indicates little degradation in performance from that of the typical Gaussian CRBM. Through simulation experiments, the CRBM with nanoscale MOSFET noise shows the ability to reconstruct training data, although it takes longer to converge to equilibrium. The results in this thesis do not prove that nanoscale MOSFET noise can be exploited in all contexts and with all data, for probabilistic computation. However, the result indicates, for the first time, that nanoscale MOSFET noise has the potential to be used for probabilistic neural computation hardware implementation. This thesis thus introduces a methodology for a form of technology-downstreaming and highlights the potential of probabilistic architecture for computation with future nanoscale MOSFETs