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Power Electronic Converters
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
A junction gate field-effect transistor (JFET) is a three-terminal device similar to a MOSFET that can be used as an electronically controlled switch. It is also a unipolar device like a MOSFET and is voltage controlled. Unlike a MOSFET, a JFET is usually a normally ON device where electric charge flows through a semiconducting channel between source and drain terminals when there is no voltage between its gate and source terminals. A reverse bias voltage needs to be applied between the gate and source terminals to ‘pinch’ the conducting channel and impede the electric current and switch off the device.
Characterization, Part II
Published in Edwin S. Oxner, Fet Technology and Application, 2020
If we take a JFET chip measuring 0.580 mm2, the power dissipation in a TO-52 header is rated at 300 mW. The same chip mounted in a T0-205 header offers a power dissipation of 3 W, an improvement of 10:1!
Modular Solar Energy Systems
Published in Yatish T. Shah, Modular Systems for Energy and Fuel Recovery and Conversion, 2019
In power electronics applications, a JFET is used as a switch that turns on and off. In low power electronics, a JFET can also be used as an amplifier and/or a gate-controlled variable resistor. For this project, we are proposing a controller for a high-voltage SiC JFET that will detect a fault condition fast and adjust the gate drive of the JFET to limit the fault current in addition to the self-heating phenomenon.
Voltage-controlled oscillators using CFOAs with correction terminal Z
Published in International Journal of Electronics, 2023
To stabilise the amplitude of the output signal similar to the oscillators (Sedra et al., 2020; Seifart, 2003; Sotner et al., 2017; Stoyanov et al., 1999; Tietze & Schenk, 2008) with classical operational amplifiers to the negative feedback of the oscillator in Figure 4a an automatic gain control (AGC) block is added (VCO2). The proposed circuit diagram of a VCO2 is represented in Figure 4c. The AGC block includes: a peak detector composed a diode and a capacitor ; resistive voltage divider ; reference voltage source and N-channel JFET . In this case, the negative feedback is implemented through the and the impedance of the channel in the . The value of the is tuned by the amplitude of the output signal.
A Single Phase GaN GITs-Based Bidirectional Multilevel Inverter for High Voltage Grid Tied Photovoltaic Power System
Published in Electric Power Components and Systems, 2023
Muhammad Mohsin Naveed, Alberto Castellazzi
The PWM generator PCB has three inputs: The first input is the ±5 V DC supply, the second input is for the modulation wave using BNC connector, and the third input is for the carrier wave using BNC connector. The C1-C7 and C9-C12 are the decoupling capacitors placed at the input supply. The TL072ACD Low-Noise JFET-Input operational amplifier and LM311D Quad Differential Comparator IC from Texas Instruments are used as a comparator. The SN74ACT00D Quadruple 2-Input Positive-NAND Gates IC and CD74AC14M Hex Schmitt-Trigger inverter IC from Texas Instruments are used in the PWM signal generation. The 74ACT08SC Quad 2-Input and Gate IC from Fairchild with a resistor, capacitor, and diode network are used for dead time generation. The PWM signals obtained are marked as M1, M2, M3, and M4. The 16 kHz output of the PWM generator PCB is shown in Figure 10 for power devices M1 and M2. The PWM generator PCB is tested for PWM signal generation up-to 64 kHz. The dead time in the hardware is set to be 150 ns.
A 100-Mrad (Si) JFET-Based Sensing and Communications System for Extreme Nuclear Instrumentation Environments
Published in Nuclear Technology, 2022
F. Kyle Reed, M. Nance Ericson, N. Dianne Bull Ezell, Roger A. Kisner, Lei Zuo, Haifeng Zhang, Robert Flammang
Baseband and carrier leakage of a Gilbert mixer are attributed to component mismatches in the mixing circuit and require filtering to minimize any interference. Even with filtering, these artifacts consume energy and decrease the efficiency of the electronics. Mixer mismatch occurs both intrinsically from the transistor physical properties and extrinsically from inequalities in component values and trace lengths. The effects of these mismatches have been characterized in CMOS and BJT Gilbert cell mixers, which can be extrapolated into JFET mixers.23,24 Mismatches may become more prevalent in mixers through ionizing-radiation-induced conductivity increases, transistor leakage, gain variations, and threshold voltage variations. To mitigate these mismatches, JFET current-voltage characteristics were hand matched to less than 1% using an Agilent Technologies B1500A semiconductor device analyzer.