Output Junction Research Articles

Analysis of the Usefulness Range of the Averaged Electrothermal Model of a Diode–Transistor Switch to Compute the Characteristics of the Boost Converter

In the design of modern power electronics converters, especially DC-DC converters, circuit-level computer simulations play an important role. This article analyses the accuracy of computations of the boost converter characteristics in the steady state using an electrothermal averaged model of a diode–transistor switch containing an Insulated Gate Bipolar Transistor (IGBT) and a rapid switching diode. This model has a form of a subcircuit for SPICE (Simulation Program with Integrated Circuit Emphasis). The influence of such factors as the switching frequency of the transistor, the duty cycle of the signal controlling the transistor, the input voltage, and the output current of the boost converter on the accuracy of computing the converter output voltage and junction temperature of the IGBT and the diode were analysed. The correctness of the computation results was verified experimentally. Based on the performed computations and measurements, the usefulness range of the model under consideration was determined, and a method of solving selected problems limiting the accuracy of computations of the characteristics of this converter was proposed.

Accurate Operating Analysis of Boundary Mode Totem-Pole Boost PFC Converter Considering the Reverse Recovery of mosfet

The boundary conduction mode (BCM) totem-pole boost power factor correction (PFC) topology is becoming popular in high-efficiency and high power density applications because of its advantages of fewer devices and low conduction losses. The ideal design methodology for the BCM boost converter ignores the reverse recovery of mosfet s’ body diode and the resonance between the inductance and output junction capacitances of switches. However, as the switching frequency increases, these two factors affect the peak value of the inductance current and the switching frequency significantly, which are critical parameters for the boost PFC inductor design. In order to calculate the practical peak current and switching frequency range accurately, this letter proposes an analytical reverse recovery model of the body diode and presents accurate switching cycle operating modes. Either the predicted inductance peak current or the switching frequency range matches the measured result on a 600-W totem-pole boost PFC prototype.

Junction Surface Recombination Concept as Applied to Silicon Solar Cell Maximum Power Point Determination Using Matlab/Simulink: Effect of Temperature

In this work, we study the method for determining the maximum of the minority carrier recombination velocity at the junction Sfmax, corresponding to the maximum power delivered by the photovoltaic generator. For this, we study the temperature influence on the behavior of the front white biased solar cell in steady state. By solving the continuity equation of excess minority carrier in the base, we have established the expressions of the photocurrent density, the recombination velocity on the back side of the base Sb, and the photovoltage. The photocurrent density and the photovoltage are plotted as a function of Sf, called, minority carrier recombination velocity at the junction surface, for different temperature values. The illuminated I-V characteristic curves of the solar cell are then derived. To better characterize the solar cell, we study the electrical power delivered by the base of the solar cell to the external charge circuit as either junction surface recombination velocity or photovoltage dependent. From the output power versus junction surface recombination velocity Sf, we have deduced an eigenvalue equation depending on junction recombination velocity. This equation allows to obtain the maximum junction recombination velocity Sfmax corresponding to the maximum power delivered by the photovoltaic generator, throughout simulink model. Finally, we deduce the conversion efficiency of the solar cell.

An Integratable Planar Waveguide Power Divider With Anti-Phases and Full Bandwidth

A novel integratable planar T-junction waveguide power divider, a so-called TEH(E-plane input and H-plane output) junction waveguide power divider, with anti-phase outputs and full bandwidth is proposed in this letter. It is basically a E-plane waveguide T-junction with its input port rotated around the axis of the two output ports by 90 degrees to form a planar structure. In order to expand its operation bandwidth, several stages of matching sections are added between the coupling cavity and each port. In order to verify the concept, a standard waveguide port TEH junction divider is designed and tested as an example. From the tested results, the reflection coefficient is lower than −20 dB and phase difference between the two output ports is within 177 +/−3 degrees in the full bandwidth from 26.3 to 40 GHz.

High-Power Light-Emitting Diodes Package With Phase Change Material

We report the fabrication and charaterization of high-power light-emitting diodes (LEDs) package with phase change material. Paraffin wax with melting point of 49.6 °C was inserted between the LED die and silicone encapsulant. The phase changing of embedded wax in a working LED is observed by studying its output flux and junction temperature. With a driving current density of 443 mA/mm$^{\mathrm {\mathbf {2}}}$ , LED sample demonstrates a decreasing of junction temperature by 19 °C and an increasing of light flux by 25% with the insertion of 6-mg paraffin wax. Optical and thermal simulations are employed to analyze the improved performance of LED package. Higher thermal conductivity of paraffin wax compared with silicone resin is considered to be reason for LED's reduced junction temperature. The high refractive index of paraffin wax is considered to be the dominant mechanism of LEDs enhanced emission.

Average Voltage Measurements of Periodic Blocking Oscillation in Resistive Superconducting Quantum Interference Device Connected to Josephson Transmission Line

Blocking oscillation (BO) is a unique operation mode of resistive superconducting quantum interference devices (RSQUIDs). The author presents experimental measurements of periodic BO by means of the average voltage method. Test circuits are fabricated using a Nb/AlOx/Nb integration process. The input/output voltage ratio in an RSQUID, of which the output is connected to a Josephson transmission line (JTL), becomes 2 under appropriate operation conditions. Since the voltage ratio is exactly proportional to the input/output switching frequency ratio, the results demonstrate the periodic BO, in which the numbers of switching during one period are 2 and 1 in the input and output junction, respectively.

Analysis of class E amplifier with both linear and nonlinear shunt capacitance at any duty cycle, grading coefficient and supply modulation

This work studies the effects of the drain pn capacitance grading coefficient, duty cycle and supply modulation on the operation of class E amplifier. The class E operation analysis with a combination of nonlinear and linear output capacitances is revisited and duty cycle is added to the equations to allow further investigations for optimum class E circuit tuning. The presented analysis method can be used for synthesis as well, where necessary load components are calculated for a transistor with a specific grading coefficient both in the output capacitance and in the nonlinear feedback capacitance. Further, the grading coefficient of the nonlinear output capacitance is varied in the paper while investigating the changes in normalized peak voltages and harmonics. Drain efficiency, supply-to-amplitude modulation (V dd /AM) and supply-to-phase modulation (V dd /PM) are studied. It is shown that by varying the device duty cycle, one can scale the optimum load and the level of peak voltages over the switching device. Also, the choice of grading coefficient affects the drain efficiency, V dd /AM and V dd /PM behaviour of the class E amplifier. Last, a case study about increasing the efficiency of a class E amplifier with hyperabrupt output junction capacitance is shown.

A Novel Symmetrical Rectifier Configuration With Low Voltage Stress and Ultralow Output-Current Ripple

The dc-dc topologies with capacitive output filter are going to be widely used especially for high-output current applications because of its inherent advantages in the lower voltage stress on rectifiers and the smaller occupied printed circuit board layout area at the secondary side. However, the parasitic resonance between the equivalent leakage inductance of the power transformer and the equivalent output junction capacitance of the rectifier still practically exists in the center-tapped rectification configuration, which leads to considerable voltage ringing on the rectifier and then results in the utilization of the rectifier with much higher breakdown voltage rate and the decrease of conversion efficiency. Moreover, the relatively larger output-current ripple induces the both larger conduction loss in the secondary-side windings of the power transformer and the capacitive output filter. In this paper, a novel symmetrical rectifier configuration is proposed, which can effectively clamp the practical voltage stress on the rectifier without any parasitical voltage spike and reduce the output-current ripple due to the bypass effect of the auxiliary flying-balancing capacitors. The leakage inductance and the output filter capacitor can be treated as an inherent small LC filter to reduce the output voltage ripple further. Based on the theoretical analysis and the optimal design considerations, a 300-W lab-made LLC resonant dc-dc converter with this proposed configuration is built up to verify its advantages in high conversion efficiency.

Asymmetric exclusion processes on [formula omitted]-input [formula omitted]-output junctions with parallel update

In this paper, we investigate totally asymmetric exclusion processes (TASEPs) on lattices with an m -input n -output junction in parallel update. A general theoretical solution for traffic dynamics of TASEPs with a junction is developed. More interestingly, m -input n -output junctions can be classified by a parameter, λ = m / n . The junctions with the same λ exhibit the same dynamic properties (e.g., phase diagrams, stationary currents, and density profiles). When the number of m and/or n changes, the low-density and high-density regions can be measured qualitatively and quantitatively. The phase diagram is obtained from a simple mean-field approximation and supported by computer simulations. Stationary current and density profiles are calculated which show good agreement with computer simulations.

On theory of the indirect coupling photodetection

The paper investigates the theory about indirect coupling photodetection, and points out severe mistakes in its theoretical basis. Experiments show that, excluding the output current created by photo-generated carriers directly diffusing to the output junction, and applying the constant photo-generated voltage across the illuminated open-circuit PN junction, the output current of indirect coupling photodetector approaches the dark current of the output junction, which indicates that the injection current of the illuminated open-circuit PN junction is hard to be extracted.

Characterization of the IF Noise of a Submillimeter SIS Receiver

A fitting method is presented here for the accurate characterization of the IF noise contribution of a sub-millimeter SIS receiver. By fitting the mixer's IF output power response and junction's IV curve of an SIS mixer without LO pumping, we can obtain the IF noise contribution, the physical temperature of the isolator connected just behind the SIS mixer, the output mismatching of the mixer, and the total gain of the EF chain. Differing from a conventional method, which only uses the normal-state (linear) branch of the junction's IV curve, the method proposed here also includes the nonlinear portion around the gap voltage, The dynamic resistance in this portion is varied dramatically, providing us a good probe to characterize the output mismatching of the mixer, as well as other parameters.

Eliminating Spurious Memories in a Network of Chaotic Elements

A globally coupled map GCM model is a network of chaotic elements that are globally coupled with each other. We previously proposed an associative memory system based on GCM, which has a better ability than the Hopfield network. This result indicates that the dynamics of our system is more efficient than that of the Hopfield network. However, even in our system, spurious memories, that is, the system's equilibria that do not correspond to any of the proper memories, do exist. In this article a modified associative memory system is proposed in which spurious memories are noticeably reduced. This is achieved by modifying the chaotic dynamics of the system. With this improvement, our system's memory capacity and basin volumes are expanded a great deal. Some experimental results in comparison with those of a neural network that employs a nonmonotonic output junction are also shown.

Experimental investigation of a high frequency sampling system based on shunted Josephson junctions

The authors propose a new type of sampler design based on shunted junctions ( beta c=1). The sampler is to be used for the investigation of single flux quantum devices (RSFQ) employing similar junctions (Kaplunenko et al. 1989, Filippenko et al. 1991). They measure the time resolution of the sampler and delay time of the shunted Josephson junction array. The circuit was manufactured on a single chip and was DC powered. They employed Nb-AlOx-Nb tunnel junctions of 300 A m-2 critical current density and observed Josephson oscillations of the output junction at frequencies from 6 to 50 GHz. Despite a long plasma period of 20 ps the time resolution was 5 ps. The transmission line of 27 Josephson junctions (critical current 165 mu A each) demonstrated time delay of 0.5 ps mu A-1.

Analysis of quasiparticle injection three-terminal device

Abstract The QPI (quasiparticle injection) devices have the most transistor-like characteristics in many superconducting three-terminal devices. In particular, Quiteron which operates with the principle of suppression of the energy gap only to modulate the conductance of the output junction has a promising feature, such as a large gain, non-latching operation, and binary inversion. In this paper, we have investigated the behavior of the energy gaps to analyze the characteristics of the QPI devices. Current-voltage characteristics of QPI device is calculated by using these values of the energy gaps. First we have introduced the nonequilibrium GL equation. Then we have derived a set of equations for QPI devices by using this equation. It is found that the energy gap of middle layer has the singularity under quasiparticle injection and the QPI device may have a large gain for suitable junction resistances.