Switching Circuitry Research Articles

Design and construction of wireless water level control system with motor protector

This research work presents the design and construction of a micro-controller-based wireless water level control system. The need to bring a solution to the problem of water shortage in various places by eliminating one of the culprit; waste of water during pumping and dispensing into overhead thanks, calls for an automated control system which puts into consideration, means of avoiding mechanical tears and wears that arises with the use of robes as water level sensor, through the incorporation of wireless water level sensor in place of robes in sensing the water level in the modeled tank. To solve this problem, circuit analysis and design, of the five main sub-circuitry units, this includes: power supply unit, logic and switching circuitry unit, relay unit, LCD display unit was carried out using ultrasonic water level sensor, AT89S51 microcontroller, LCD module relay circuitry system and a few discrete components. The design of the controller in this scenario is not just cost effective but helps in avoiding mechanical tears and wears that arises with the use of robes as water level sensor, by providing an improvement on existing water level control system through the incorporation of wireless water level sensor in place of robes in sensing the water level in the modeled tank.

Performance Investigation of 17 Level Reduced Switch Count Multilevel Inverter

The primary objective of this paper is to introduce a 17-level multilevel inverter with only eight power switches and three diodes that can be suitable for electric vehicle applications. This setup utilizes three distinct unequal DC sources to create the 17 levels of output voltage waveforms. The modes of operations of the proposed topology have been discussed in detail. The calculation of conduction losses, switching losses, efficiency, total standing voltage, and cost function per level for the suggested inverter has been elaborated. Due to more semiconductor power switches, diodes, capacitors, driver circuits, and DC sources in typical inverters, switching losses, costs, and harmonic distortion are increased. The nearest-level control technique has been utilized to control the switching elements of the recommended configuration. The performance comparison of various multilevel inverter topologies has also been discussed. The suggested multilevel inverter provides a higher efficiency of 98.60%, cost function of 3.6 for a weight coefficient of 1, improved power quality, and higher reliability. A reduction in the power switches significantly reduces the convolution of switching circuitry. The total harmonic distortion produced by this inverter is 3.49%, which comes under the IEEE standard of 5%.

Design and Implementation of Modified Multilevel Inverter FED BLDC Motor for Electric Vehicle Application

In this work a modified hybrid multilevel inverter with reduced device is proposed. The system considerably reduces the quantity of power electronic power switches to twenty-one so as to create fifteen level three phase output, whereas conventional structures require higher number of power devices. Higher number of power switches leads to increased distortion, losses and cost. The recommended circuit gives better response, higher efficiency, reduced cost, high reliability and fault tolerance. Decrease in number of power switches, intensely diminishes the convolution of the switching circuitry.

Millimeter-Wave single-pole-double-throw switch design with Stacked-FET topology using network cascading analysis

In this paper, the correlation between the key performance of the shunt-type single-pole-double-throw (SPDT) switch circuitry and the intrinsic device parameters is theoretically investigated by network cascading approach. Through rigorous analysis, we concluded that the intrinsic device parameters such as the gate-to-drain capacitance (Cgd) have direct impact on the performance due to the scaling of the gate length. The analysis results were verified by the implementation of an SPDT switch at millimeter-wave frequency using stacked-FET topology. An input power at 1-dB compression point (P1dB) of greater than 30 dBm was measured from 15 to 35 GHz, exhibiting an enhancement of 6-dB in comparison with the conventional topology.

Design analysis and control of step‐up converter with reduced switch stress

SummaryIn light of the increasing share of renewable energy sources (RES) in electricity generation, the research community is directing their attention toward developing highly efficient DC‐DC high‐gain step‐up converters. These converters are designed to exhibit reduced voltage stress on the switching devices (semiconductors). This paper presents a comprehensive study of a switch voltage stress‐reduced step‐up converter that offers a range of additional features, including the availability of a common ground point, continuous input current, simple two‐mode continuous conduction mode (CCM) operation, wide duty cycle range, and quadratic boosting factor. To achieve the aforementioned features, the converter utilizes two switches with the same operating modes, eliminating the need for complex switching circuitry. Operational modes, steady‐state analysis, and design considerations have been presented in detail. Comparative analysis indicates that the voltage conversion ratio per number of devices in the proposed topology is significantly higher than that of similar topologies. In addition, the voltage stress of switches is considerably less than the topologies addressed in the literature. The study further includes detailed mathematical and experimental analyses, small signal analysis, and hardware implementation to support the theoretical findings. The converter's efficiency has been thoroughly analyzed along with thermal analysis to ensure its reliability.

Multi-Mode Yagi Uda Patch Array Antenna With Non-Linear Inter-Parasitic Element Spacing

A low-profile and broad steerable patch array antenna is presented. The improvement of the multi-directional functions from the broadside is very limited for the patch array antenna. In this work, the number of directional beams is enhanced by 40% using a novel approach, inter-parasitic element expansion technique and adopted only four PIN diode switches. Results in simulation and measurement have verified that the patch parasitic array antenna is capable -of generating seven beam patterns directed towards −52°, −30°, −10°, 0°, +10°, +30°, and +52° at the xz-plane. Applying the inter-parasitic element spacing’s optimization and minimizing the switching circuitry using four RF PIN diodes on the parasitic elements have contributed to the gain achievement of more than 7 dBi.

Development of ARM and CPLD Based Multi Controller Board

Over the course of the last ten years, the number of researchers, academicians, and industry people participating in development boards has significantly increased. In order for product development departments to realize their objective of generating higher-quality items, it is vital for them to integrate the processes of developing both hardware and software. The fundamental concept that supports a multi-controller board which incorporates ARM and CPLD cores has been materialised into a working product. There is not yet a version of a Multi-Controller Boards that is currently available in the marketplace that incorporates both CPLD and ARM into such a single board at the same time. This is the case despite the fact that such a board would be desirable. Creating a board that can accommodate many controllers is the primary objective of this endeavor. In addition to a switching circuit, this board will feature an ARM chipset as well as a CPLD chipset as its primary components. In order to transition between the two chipsets, the switching circuitry have been utilized.

Efficient Hardware Acceleration of Sparsely Active Convolutional Spiking Neural Networks

Spiking neural networks (SNNs) compute in an event-based manner to achieve a more efficient computation than standard neural networks. In SNNs, neuronal outputs are not encoded as real-valued activations but as sequences of binary spikes. The motivation of using SNNs over conventional neural networks is rooted in the special computational aspects of spike-based processing, especially the high degree of sparsity of spikes. Well-established implementations of convolutional neural networks (CNNs) feature large spatial arrays of processing elements (PEs) that remain highly underutilized in the face of activation sparsity. We propose a novel architecture optimized for the processing of convolutional SNNs (CSNNs) featuring a high degree of sparsity. The proposed architecture consists of an array of PEs of the size of the kernel of a convolution and an intelligent spike queue that provides a high PE utilization. A constant flow of spikes is ensured by compressing the feature maps into queues that can then be processed spike-by-spike. This compression is performed at run-time, leading to a self-timed schedule. This allows the processing time to scale with the number of spikes. Also, a novel memory organization scheme is introduced to efficiently store and retrieve the membrane potentials of the individual neurons using multiple small parallel on-chip RAMs. Each RAM is hardwired to its PE, reducing switching circuitry. We implemented the proposed architecture on an FPGA and achieved a significant speedup compared to previously proposed SNN implementations (~10 times) while needing less hardware resources and maintaining a higher energy efficiency (~15 times).

Onto a higher power handling for very high frequency direct antenna modulation

Antennas constrained to platforms that require miniaturisation, significantly smaller than the wavelength of the desired frequency, are inefficient radiators and limited to narrowband operations. To overcome these limitations, a technique called direct antenna modulation (DAM), is incorporated with electrically small antennas to enable transmission of high-bandwidth signals through narrowband antennas. DAM utilises switching circuitry to directly modulate the antenna at its corresponding peak energy moments all while being synchronised to the input signal, yet previous iterations were susceptible to low transmit powers due to limitations in the switching network's power handling capability and tremendous coupling between transistor ports that results in an ambiguous switching signal at the gate. A frequency shift keyed (FSK) DAM antenna topology is proposed, which is capable of high-power transmission through a geometrically symmetrical switching circuitry integrating pairs of complementary GaN transistors. The symmetry assists in removing coupling among transistor ports to effectively switch the transistors OFF and ON without regard to the input RF power. The authors’ theoretical analysis agrees with our simulations and far-field measurements which show the FSK DAM antenna topology is capable of transmit powers up to −1 dBm given a 42 dBm of input RF power.

Solar Water Pumping Model Using Zeta Converter for Irrigation Application

A solar pumping model is proposed in this paper using a Brushless DC (BLDC) motor. Zeta converter is used as a DC-DC link between the voltage source inverter and the PV array. Zeta converter enables soft starting of the BLDC motor and the speed control is achieved by simple variation of DC link voltage, thereby eliminating the need for complex switching circuitry. Zeta converter belongs to the class of buck-boost converter hence offers a wide range of operating voltage. The proposed model is simple and cost-effective so it can be practically implemented with minimum cost. The proposed model is tested for its suitability in the MATLAB/Simulink environment.

Numerical simulation of microplasma field-effect transistor at low voltages

In this study, two-dimensional simulation of the microplasma field-effect transistor (MOPFET) was performed using COMSOL Multiphysics along with BOLSIG $$+$$ software and LXCat database. At first, argon plasma generation in the electric discharge channel was investigated in the case of an RF-biased drain terminal. The Townsend criterion for self-sustaining discharge was modified by including ion-enhanced secondary ionisation concerning to the micrometer scale of the discharge gap. The simulation results showed that the level of the gate electrode voltage serves as a tuner for the MOPFET current, and it changes the gas breakdown voltage. The results of the 2D simulation showed that the polarity of the gate voltage is crucial for controlling the MOPFET current and the operation of switching circuitry. To increase current, a new gas mixture was proposed and simulated. The $$I_{\mathrm {DS}}{-}V_{\mathrm {DS}}$$ characteristic of the MOPFET was obtained with Ar/Hg (98:2). Static transconductance and $$h_{\mathrm {FE}}$$ of the MOPFET were also evaluated. The results of this study can be used for designing and operating the MOPFET in an electronic circuit.

On-Site Traversal Fractional Open Circuit Voltage with Uninterrupted Output Power for Maximal Power Point Tracking of Photovoltaic Systems

The fractional open-circuit voltage (FOCV) method is commonly adopted to track maximal power point of photovoltaic systems due to easy implementation and cost-effectiveness. However, the FOCV method is confronted with unstable output power and limited tracking accuracy. This paper proposes a novel on-site traversal FOCV method with uninterrupted output power and increased tracking accuracy through simulation and experimental verifications. Each solar cell is connected with a bypass diode and switching circuitry, so that specific solar cell can be traced and measured consecutively for determining its maximal power point (MPP). MATLAB/Simulink simulation results show that, in the time-varying irradiance case, the proposed method achieves a low ripple factor of 0.13% in 11–13 h and 0.88% in 9–15 h, under the typical 24 h irradiance curve. In the spatial-varying irradiance case, the accuracy of the proposed method reaches 99.85%. Compared with other FOCV methods, like pilot cell and semi pilot cell methods, the proposed method is of higher accuracy with a limited ripple effect. Experimental results show that this method can effectively trace different output performance of specific solar cell while generating stable output voltage with a low ripple factor of 1.55%, proving its compatibility with distributed sensing and applicability in smart photovoltaic systems.

A Robust Multioutput Self-Regulated Rectifier for Wirelessly Powered Biomedical Applications

A robust multioutput self-regulated rectifier without any switching circuitry is proposed in this letter for wirelessly powered biomedical devices, especially for neural stimulators. The proposed system utilizes the series and parallel resonant configuration for low- and high-side outputs, respectively, by using only one resonant capacitor. The proposed system provides dual high voltages of ±14 V for neuro stimulator and low voltage of 2.1 V for operating systems such as read-out and digital circuits.

Toward a Spectrally Efficient FSK Direct Antenna Modulation

Antennas in platforms where the physical dimensions are significantly smaller than the wavelength of the frequency of interest are limited to narrowband operations. A technique that enables transmission of such signals through narrowband antennas is called Direct Antenna Modulation (DAM). DAM utilizes switching circuitry to directly modulate the antenna at its maximum energy moments synchronized with the input RF signal. In this paper, we propose a method of attaining higher-order, N, frequency shift keyed, NFSK, modulation through a high Quality-factor electrically small antenna to achieve higher bit rates and better spectral efficiency within an instantaneous bandwidth. A DAM antenna transmitting a frequency shift keyed signal using four carrier frequencies, 4FSK, was designed, prototyped, and measured. Its electrical size is 0.018λ×0.02λ. A pseudorandom 8-bit and 16-bit sequence were transmitted through the 4FSK DAM antenna and received in the far-field. The results show that such a topology provides a roadmap in attaining even higher modulation orders, thus, higher spectral efficiency.

A Fast Modular Semiconductor-Based Marx Generator for Driving Dynamic Loads

The challenging demands of pulsed electron beam devices (such as the GESA device) with respect to their pulsed power supply have led to the development of a new semiconductor-based Marx generator. At a maximum output voltage of 120 kV and 600-A pulse current for a duration of up to 100 μS, stepwise arbitrary output waveforms are desired. A fast rise time of the generator is achieved by using fast switching circuitry, low inductance capacitors, and a low inductance stage arrangement. For low jitter triggering of all stages and efficient signal transmission, the generator uses an optical bus system for communication. Due to the inherent dynamic load characteristics of the GESA device, the generator features a fast overcurrent protection scheme. This paper presents selected design aspects of the generator and their validation in a small-scale assembly able of delivering up to 8 kV at 600-A load current.

Proposed circuit design could increase switching efficiency in wind energy grids

Simulations show improved dynamic performance in wind energy grids that use dual parallel DC-DC chopper switching circuitry.

Low-power content addressable memory (CAM) array for mobile devices

Large-capacity content-addressable memory (CAM) is beneficial in a variety of applications that require high-speed lookup table. It is used extensively in low power CPU design, network routers, and cache controllers. Content addressable memory system includes CAM cells that contains a compare-circuit and a memory bit-cell that stores complementary bits. The compare circuit consists of complementary inputs to receive the complementary stored bits, and an input node to receive a single-ended reference bit. The main CAM design challenge is to reduce the power consumption associated with large amount of parallel switching circuitry, without sacrificing speed or density.This paper presents a novel CAM circuit level implementation aiming at reducing the comparator power and the crowbar current. Consequently, the average current consumption during CAM operation is reduced. In addition, the proposed circuit topology eliminates the need to route the complementary data which saves routing resources. Simulation results using 22nm process technology shows that the elimination of the crowbar current during writing operation saves 40% of power for single bit-cell CAM, while sharing the compare circuitry among 8bit-cells CAM saves 14% of the power without any performance impact regarding chip area.

Fully differential switching topology for mm‐wave dual‐mode LO‐distribution circuitry

A novel switching circuitry for fully differential millimetre-wave applications is presented. The structure of the proposed switching architecture includes 90 nm CMOS transistors and a distributed-active-transformer. To minimise the chip size, an innovative topology based on lumped components is investigated, resulting a total size of <0.025 mm2. The performance of the designed switch is validated within a dual-mode local oscillator-distribution circuitry of a V-band transceiver.

Model of anaesthetic induction by unilateral intracerebral microinjection of GABAergic agonists.

General anaesthetic agents induce loss of consciousness coupled with suppression of movement, analgesia and amnesia. Although these diverse functions are mediated by neural structures located in wide-ranging parts of the neuraxis, anaesthesia can be induced rapidly and reversibly by bilateral microinjection of minute quantities of γ-aminobutyric acid (GABA)A -R agonists at a small, focal locus in the mesopontine tegmentum (MPTA). State switching under these circumstances is presumably executed by dedicated neural pathways and does not require widespread distribution of the anaesthetic agent itself, the classical assumption regarding anaesthetic induction. Here it was asked whether these pathways serve each hemisphere independently, or whether there is bilateral redundancy such that the MPTA on each side is capable of anaesthetizing the entire brain. Either of two GABAA -R ligands were microinjected unilaterally into the MPTA in awake rats, the barbiturate modulator pentobarbital and the direct receptor agonist muscimol. Both agents, microinjected on either side, induced clinical anaesthesia, including bilateral atonia, bilateral analgesia and bilateral changes in cortical activity. The latter was monitored using c-fos expression and electroencephalography. This action, however, was not simply a consequence of suppressing spike activity in MPTA neurons, as unilateral (or bilateral) microinjection of the local anaesthetic lidocaine at the same locus failed to induce anaesthesia. A model of the state-switching circuitry that accounts for the bilateral action of unilateral microinjection and also for the observation that inactivation with lidocaine is not equivalent to inhibition with GABAA -R agonists was proposed. This is a step in defining the overall switching circuitry that underlies anaesthesia.

Design and Development of a PC based ECG Equipment

ECG is very important for diagnosis of cardiac disorders but most ECG equipment come from developed countries with very costly procurement and maintenance. Therefore, unless the technology is developed indigenously, common people in countries like Bangladesh will not get the benefits of modern healthcare technology. With the advent of personal computers (PC) at low cost, a PC based ECG equipment is also worth developing since many people already own a PC, thereby reducing the overall cost. With this view a PC based ECG equipment was designed and developed from the basics. An attempt was made to utilize maximum components and spares available in the local market. The main unit is based on a low cost but quality instrumentation amplifier IC with high common mode rejection ratio. Active filters were designed using common operational amplifier ICs. Right leg drive circuitry to reduce 50Hz noise of mains ac was kept as an option. Analog signal switching circuitry was used to obtain 12 Lead configurations, which were programme controlled, through graphical user interface. To achieve electrical isolation between patient and the mains ac, an analogue optical isolation circuit was designed and developed. Finally the analogue signal was converted to digital data and interfaced to a personal computer through its USB port using a microcontroller. The required power is obtained by USB port 5V supply. A medical grade isolated dc to dc converter was designed to power the patient side circuitry. Proper patient safety issues were followed in the design. Calibration was performed to make the equipment as accurate as possible. Outputs from several subjects were compared with that of reliable commercial equipment and were found to be satisfactory by cardiac experts. DOI: http://dx.doi.org/10.3329/bjmp.v6i1.19757 Bangladesh Journal of Medical Physics Vol.6 No.1 2013 39-54