scholarly journals Two-Terminal Electronic Circuits with Controllable Linear NDR Region and Their Applications

2021 ◽  
Vol 11 (21) ◽  
pp. 9815
Author(s):  
Vladimir Ulansky ◽  
Ahmed Raza ◽  
Denys Milke
Keyword(s):  
Phase Noise ◽  
High Efficiency ◽  
Differential Resistance ◽  
Negative Resistance ◽  
Single Frequency ◽  
Electronic Circuits ◽  
Output Current ◽  
Voltage Range ◽  
Voltage Controlled Oscillators ◽  
Current Mirrors

Negative differential resistance (NDR) is inherent in many electronic devices, in which, over a specific voltage range, the current decreases with increasing voltage. Semiconductor structures with NDR have several unique properties that stimulate the search for technological and circuitry solutions in developing new semiconductor devices and circuits experiencing NDR features. This study considers two-terminal NDR electronic circuits based on multiple-output current mirrors, such as cascode, Wilson, and improved Wilson, combined with a field-effect transistor. The undoubted advantages of the proposed electronic circuits are the linearity of the current-voltage characteristics in the NDR region and the ability to regulate the value of negative resistance by changing the number of mirrored current sources. We derive equations for each proposed circuit to calculate the NDR region’s total current and differential resistance. We consider applications of NDR circuits for designing microwave single frequency oscillators and voltage-controlled oscillators. The problem of choosing the optimal oscillator topology is examined. We show that the designed oscillators based on NDR circuits with Wilson and improved Wilson multiple-output current mirrors have high efficiency and extremely low phase noise. For a single frequency oscillator consuming 33.9 mW, the phase noise is −154.6 dBc/Hz at a 100 kHz offset from a 1.310 GHz carrier. The resulting figure of merit is −221.6 dBc/Hz. The implemented oscillator prototype confirms the theoretical achievements.

scholarly journals Electronic Circuit with Controllable Negative Differential Resistance and its Applications

Electronics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 409 ◽  
Author(s):  
Vladimir Ulansky ◽  
Ahmed Raza ◽  
Hamza Oun
Keyword(s):  
Negative Differential Resistance ◽  
Differential Resistance ◽  
Negative Resistance ◽  
Single Frequency ◽  
Frequency Multipliers ◽  
Voltage Controlled Oscillators ◽  
Current Voltage ◽  
Junction Transistor ◽  
Current Voltage Characteristics ◽  
Simulation Results

Electronic devices and circuits with negative differential resistance (NDR) are widely used in oscillators, memory devices, frequency multipliers, mixers, etc. Such devices and circuits usually have an N-, S-, or Λ-type current-voltage characteristics. In the known NDR devices and circuits, it is practically impossible to increase the negative resistance without changing the type or the dimensions of transistors. Moreover, some of them have three terminals assuming two power supplies. In this paper, a new NDR circuit that comprises a combination of a field effect transistor (FET) and a simple bipolar junction transistor (BJT) current mirror (CM) with multiple outputs is proposed. A distinctive feature of the proposed circuit is the ability to change the magnitude of the NDR by increasing the number of outputs in the CM. Mathematical expressions are derived to calculate the threshold currents and voltages of the N-type current-voltage characteristics for various types of FET. The calculated current and voltage thresholds are compared with the simulation results. The possible applications of the proposed NDR circuit for designing single-frequency oscillators and voltage-controlled oscillators (VCO) are considered. The designed NDR VCO has a very low level of phase noise and has one of the best values of a standard figure of merit (FOM) among recently published VCOs. The effectiveness of the proposed oscillators is confirmed by the simulation results and the implemented prototype.

A 10 GHz high-efficiency and low phase-noise negative-resistance oscillator optimized with a virtual loop model

2009 ◽  
Vol 30 (11) ◽  
pp. 115001
Author(s):  
Wang Xiantai ◽  
Jin Zhi ◽  
Wu Danyu ◽  
Shen Huajun ◽  
Liu Xinyu
Keyword(s):  
Phase Noise ◽  
High Efficiency ◽  
Negative Resistance ◽  
Loop Model ◽  
Low Phase Noise ◽  
Virtual Loop

scholarly journals A New Current-Shaping Technique Based on a Feedback Injection Mechanism to Reduce VCO Phase Noise

Sensors ◽  
2021 ◽  
Vol 21 (19) ◽  
pp. 6583
Author(s):  
Francisco Javier del Pino Suárez ◽  
Sunil Lalchand Khemchandani
Keyword(s):  
Phase Noise ◽  
Supply Voltage ◽  
Cmos Technology ◽  
Negative Resistance ◽  
Chip Area ◽  
Load Variations ◽  
Voltage Controlled Oscillators ◽  
Radar Sensors ◽  
Low Area ◽  
Injection Mechanism

Inductor-capacitor voltage controlled oscillators (LC-VCOs) are the most common type of oscillator used in sensors systems, such as transceivers for wireless sensor networks (WSNs), VCO-based reading circuits, VCO-based radar sensors, etc. This work presents a technique to reduce the LC-VCOs phase noise using a new current-shaping method based on a feedback injection mechanism with only two additional transistors. This technique consists of keeping the negative resistance seen from LC tank constant throughout the oscillation cycle, achieving a significant phase noise reduction with a very low area increase. To test this method an LC-VCO was designed, fabricated and measured on a wafer using 90 nm CMOS technology with 1.2 V supply voltage. The oscillator outputs were buffered using source followers to provide additional isolation from load variations and to boost the output power. The tank was tuned to 1.8 GHz, comprising two 1.15 nH with 1.5 turns inductors with a quality factor (Q) of 14, a 3.27 pF metal-oxide-metal capacitor, and two varactors. The measured phase noise was −112 dBc/Hz at 1 MHz offset. Including the pads, the chip area is 750 × 850 μm2.

scholarly journals High power and high efficiency single-frequency 1030 nm DFB fiber laser

2022 ◽  
Vol 145 ◽  
pp. 107519
Author(s):  
Yue Tao ◽  
Song Zhang ◽  
Man Jiang ◽  
Can Li ◽  
Pu Zhou ◽  
...  
Keyword(s):  
Fiber Laser ◽  
High Power ◽  
High Efficiency ◽  
Single Frequency

Magnetic tunneling junctions based on 2D CrI3 and CrBr3: spin filtering effects and high tunnel magnetoresistance via energy band difference

2021 ◽  
Author(s):  
Li Liu ◽  
Shizhuo Ye ◽  
Jin He ◽  
Qijun Huang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Bias Voltage ◽  
Tunnel Junctions ◽  
Van Der Waals ◽  
Magnetic Tunnel Junctions ◽  
Differential Resistance ◽  
High Tunnel ◽  
Voltage Range ◽  
Negative Differential Resistance Effect ◽  
Magnetoresistance Ratio ◽  
Spin Filtering

Abstract Recently, the study on two-dimensional materials expands to the field of spintronics. The intrinsically ferromagnetic van der Waals materials such as CrI3 and CrBr3 receive much attention due to nearly 100% spin polarization and good stability, resulting in excellent performance in magnetic tunnel junctions. In this work, we design the magnetic tunnel junctions of Cu/CrI3/Cu and Cu/CrBr3/Cu with the electrodes of Cu(111) and the tunneling barrier of 4-monolayer CrI3 or CrBr3. Our first-principle calculations combined with nonequilibrium Green’s function method indicate that the CrBr3-based MTJ has a larger maximum tunneling magnetoresistance ratio than the CrI3-based MTJ. In a wide bias voltage range, the CrI3-based MTJ can maintain high spin filtering performance, while that of the CrBr3-based MTJ degrades sharply as the bias voltage increases. It is noted that negative differential resistance effect is observed in the CrBr3-based MTJ. The differences of spin transport properties between the CrI3-based MTJ and the CrBr3-based MTJ are clarified in terms of the inside device physics, including the spin-dependent projected density of states, band structures, Bloch states, and the electron density difference. This work provides some physical insights for the design of 2D van der Waals MTJ.

scholarly journals Development of 50kW High Efficiency Fast Charger with Wide Charging Voltage Range

2016 ◽  
Vol 21 (3) ◽  
pp. 267-274 ◽  
Author(s):  
Jun-Sung Park ◽  
Min-Jae Kim ◽  
Heon-Soo Jeong ◽  
Joo-Ha Kim ◽  
Se-Wan Choi
Keyword(s):  
High Efficiency ◽  
Voltage Range

scholarly journals High Efficiency Buck-Boost Converter with Three Modes Selection for HV Applications using 0.18 μm Technology

2020 ◽  
Vol 18 (2) ◽  
pp. 137-144
Author(s):  
Fouad Farah ◽  
Mustapha El Alaoui ◽  
Abdelali El Boutahiri ◽  
Mounir Ouremchi ◽  
Karim El Khadiri ◽  
...  
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Output Voltage ◽  
High Efficiency ◽  
Power Conversion ◽  
Boost Converter ◽  
Current Control ◽  
Voltage Range ◽  
Operating Modes ◽  
Soft Start

In this paper, we aim to make a detailed study on the evaluation and the characteristics of the non-inverting buck–boost converter. In order to improve the behaviour of the buck-boost converter for the three operating modes, we propose an architecture based on peak current-control. Using a three modes selection circuit and a soft start circuit, this converter is able to expand the power conversion efficiency and reduce inrush current at the feedback loop. The proposed converter is designed to operate with a variable output voltage. In addition, we use LDMOS transistors with low on-resistance, which are adequate for HV applications. The obtained results show that the proposed buck-boost converter perform perfectly compared to others architecture and it is successfully implemented using 0.18 μm CMOS TSMC technology, with an output voltage regulated to 12V and input voltage range of 4-20 V. The power conversion efficiency for the three operating modes buck, boost and buck-boost are 97.6%, 96.3% and 95.5% respectively at load current of 4A.

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