scholarly journals Impact of forward emitter current gain and geometry of pnp power transistors on radiation tolerance of voltage regulators

2010 ◽  
Vol 25 (3) ◽  
pp. 179-185 ◽  
Author(s):  
Vladimir Vukic ◽  
Predrag Osmokrovic
Keyword(s):  
Area Ratio ◽  
Voltage Regulators ◽  
Current Gain ◽  
Maximum Output ◽  
Output Current ◽  
Emitter Current ◽  
Power Transistors ◽  
Operational Characteristics ◽  
Rapid Fall ◽  
A Minor

Low-dropout voltage regulators with various geometries and technological realisations of serial pnp power transistors were exposed to ionizing radiation. Although devices with vertical emitters were considered much less susceptible to the influence of radiation on forward emitter current gain than circuits with round emitters, the experiment showed a similar degradation of current gain in both cases. The main reason of high radiation susceptibility of the examined vertical serial pnp transistor is the implementation of an interdigitated emitter, with high perimeter-to-area ratio, causing the great increase of serial transistor?s base current, but a minor influence on the maximum output current. Transistors with round emitters with small perimeter-to-area ratio expressed a moderate current gain degradation, but a rapid fall of the emitter injection efficiency, causing a significant decrease of the maximum output current. Regardless of the similar forward emitter current gain degradation, reliability and operational characteristics of two types of low-dropout voltage regulators were completely different.

scholarly journals Minimum dropout voltage on a serial pnp transistor of a moderately loaded voltage regulator in a gamma radiation field

2012 ◽  
Vol 27 (4) ◽  
pp. 333-340 ◽  
Author(s):  
Vladimir Vukic
Keyword(s):  
Integrated Circuit ◽  
High Current Density ◽  
Negative Influence ◽  
Radiation Hardness ◽  
Voltage Regulators ◽  
Current Gain ◽  
Voltage Regulator ◽  
Emitter Current ◽  
Moderate Load ◽  
Loaded Voltage

The main examined value in an experiment performed on moderately loaded voltage regulators was the serial pnp transistor?s minimum dropout voltage, followed by the data on the base current and forward emitter current gain. Minimum dropout voltage decreased by up to 12%, while the measured values of the forward emitter current gain decreased by 20-40% after the absorption of a total ionizing dose of 500 Gy. The oxide trapped charge increased the radiation tolerance of the serial lateral pnp transistor owing to the suppression of interface trap formation above the base area. Current flow through the serial transistor of the voltage regulator had an influence on the decrease in the power pnp transistor?s forward emitter current gain. Due to the operation with a moderate load of 100 mA, loss of emitter injection efficiency was not as important as during the operation with high current density, thus eliminating the negative influence of emitter crowding on the radiation hardness of the voltage regulator. For a moderate load, gain in the negative feedback reaction was enough to keep output voltage in the anticipated range. Only information procured from tests of the minimum dropout voltage on the moderately loaded voltage regulators were not sufficient for unequivocal determination of the examined integrated circuit?s radiation hardness.

scholarly journals On-line monitoring of base current and forward emitter current gain of the voltage regulator's serial pnp transistor in a radiation environment

2012 ◽  
Vol 27 (2) ◽  
pp. 152-164 ◽  
Author(s):  
Vladimir Vukic ◽  
Predrag Osmokrovic
Keyword(s):  
Automatic Measurement ◽  
Radiation Environment ◽  
Current Gain ◽  
Maximum Output ◽  
Emitter Current ◽  
Base Current ◽  
On Line ◽  
Considerable Degradation ◽  
Loaded Voltage ◽  
Internal Consumption

A method of on-line monitoring of the low-dropout voltage regulator's operation in a radiation environment is developed in this paper. The method had to enable detection of the circuit's degradation during exploitation, without terminating its operation in an ionizing radiation field. Moreover, it had to enable automatic measurement and data collection, as well as the detection of any considerable degradation, well before the monitored voltage regulator's malfunction. The principal parameters of the voltage regulator's operation that were monitored were the serial pnp transistor's base current and the forward emitter current gain. These parameters were procured indirectly, from the data on the voltage regulator's load and quiescent currents. Since the internal consumption current in moderately and heavily loaded devices was used, the quiescent current of a negligibly loaded voltage regulator of the same type served as a reference. Results acquired by on-line monitoring demonstrated marked agreement with the results acquired from examinations of the voltage regulator's maximum output current and minimum dropout voltage in a radiation environment. The results were particularly consistent in tests with heavily loaded devices. Results obtained for moderately loaded voltage regulators and the risks accompanying the application of the presented method, were also analyzed.

scholarly journals A Novel Differential Log-Companding Amplifier for Biosignal Sensing

2016 ◽  
Vol 2016 ◽  
pp. 1-7
Author(s):  
Zigang Dong ◽  
Xiaolin Zhou ◽  
Yuanting Zhang
Keyword(s):  
Power Consumption ◽  
Supply Voltage ◽  
Nonlinear Function ◽  
New Method ◽  
Total Power ◽  
Maximum Output ◽  
Output Current ◽  
Current Range ◽  
Symmetrical Configuration ◽  
Total Power Consumption

We proposed a new method for designing the CMOS differential log-companding amplifier which achieves significant improvements in linearity, common-mode rejection ratio (CMRR), and output range. With the new nonlinear function used in the log-companding technology, this proposed amplifier has a very small total harmonic distortion (THD) and simultaneously a wide output current range. Furthermore, a differential structure with conventionally symmetrical configuration has been adopted in this novel method in order to obtain a high CMRR. Because all transistors in this amplifier operate in the weak inversion, the supply voltage and the total power consumption are significantly reduced. The novel log-companding amplifier was designed using a 0.18 μm CMOS technology. Improvements in THD, output current range, noise, and CMRR are verified using simulation data. The proposed amplifier operates from a 0.8 V supply voltage, shows a 6.3 μA maximum output current range, and has a 6 μW power consumption. The THD is less than 0.03%, the CMRR of this circuit is 74 dB, and the input referred current noise density is166.1 fA/Hz. This new method is suitable for biomedical applications such as electrocardiogram (ECG) signal acquisition.

scholarly journals AlGaN/GaN High Electron Mobility Transistors on Semi-Insulating Ammono-GaN Substrates with Regrown Ohmic Contacts

Micromachines ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 546 ◽  
Author(s):  
Wojciech Wojtasiak ◽  
Marcin Góralczyk ◽  
Daniel Gryglewski ◽  
Marcin Zając ◽  
Robert Kucharski ◽  
...  
Keyword(s):  
Electron Mobility ◽  
Ohmic Contacts ◽  
High Electron Mobility Transistors ◽  
High Electron Mobility Transistor ◽  
Maximum Output ◽  
High Electron ◽  
Output Current ◽  
High Electron Mobility ◽  
Electron Mobility Transistors ◽  
Access Resistance

AlGaN/GaN high electron mobility transistors on semi-insulating bulk ammonothermal GaN have been investigated. By application of regrown ohmic contacts, the problem with obtaining low resistance ohmic contacts to low-dislocation high electron mobility transistor (HEMT) structures was solved. The maximum output current was about 1 A/mm and contact resistances was in the range of 0.3–0.6 Ω ·mm. Good microwave performance was obtained due to the absence of parasitic elements such as high access resistance.

Simple method for increasing current gain and voltage ratings of power transistors

1987 ◽  
Vol 23 (23) ◽  
pp. 1213
Author(s):  
A. Silard ◽  
F. Floru ◽  
C. Stefan ◽  
G. Nani
Keyword(s):  
Current Gain ◽  
Simple Method ◽  
Power Transistors

Acoustic wave-driven oxidized liquid metal-based energy harvester

2018 ◽  
Vol 81 (2) ◽  
pp. 20902 ◽  
Author(s):  
Jinpyo Jeon ◽  
Sang Kug Chung ◽  
Jeong-Bong Lee ◽  
Seok Joo Doo ◽  
Daeyoung Kim
Keyword(s):  
Liquid Metal ◽  
Acoustic Wave ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Energy Harvester ◽  
Metal Droplet ◽  
Acoustic Energy ◽  
Maximum Output ◽  
Output Current ◽  
Liquid Metal Droplet

We report an oxidized liquid metal droplet-based energy harvester that converts acoustic energy into electrical energy by modulating an electrical double layer that originates from the deformation of the oxidized liquid metal droplet. Gallium-based liquid metal alloy has been developed for various applications owing to the outstanding material properties, such as its high electrical conductivity (metallic property) and unlimited deformability (liquid property). In this study, we demonstrated energy harvesting using an electrical double layer between the acoustic wave-modulated liquid metal droplet and two electrodes. The proposed energy harvester consisted of top and bottom electrodes covered with the dielectric layer and a Gallium-based liquid metal droplet placed between the electrodes. When we applied an external bias voltage and acoustic wave to the proposed device, the contact area between the liquid metal droplet and the electrodes changed, leading to the variation of the capacitance in the electrical double layer and the generation of electrical output current. Using the proposed energy harvester, the maximum output current of 41.2 nA was generated with an applied acoustic wave of 30 Hz. In addition, we studied the relationships between the maximum output current and a variety of factors, such as the size of the liquid metal droplet, the thickness of the hydrophobic layer, and the distance between the top and bottom electrode plates.

An Elementary Approach to D.C. Voltage Regulators

1975 ◽  
Vol 12 (1) ◽  
pp. 88-93
Author(s):  
S. Ashok
Keyword(s):  
Equivalent Circuit ◽  
Feedback Loop ◽  
Natural Extension ◽  
Voltage Regulators ◽  
Elementary Approach ◽  
Output Current ◽  
Zener Diode ◽  
Feed Forward ◽  
Current Sampling

Feedback d.c. voltage regulators are developed as a natural extension of the simple zener diode regulator. Instead of using the usual feedback loop approach, controlled current and voltage sources are introduced in the development of a simple incremental equivalent circuit for series and shunt feedback regulators, also for input feed-forward and output current sampling.

SiC BJT's for High Power Switching and RF Applications

2002 ◽  
Vol 742 ◽  
Author(s):  
Anant Agarwal ◽  
Sei-Hyung Ryu ◽  
Craig Capell ◽  
James Richmond ◽  
John W. Palmour ◽  
...  
Keyword(s):  
Single Cell ◽  
Temperature Coefficient ◽  
Supply Voltage ◽  
Maximum Output Power ◽  
Low Frequency ◽  
Current Gain ◽  
Maximum Output ◽  
Positive Temperature ◽  
Power Gain ◽  
Power Switching

ABSTRACTIn this paper, high performance, high voltage NPN bipolar junction transistors in 4H-SiC are presented for applications in low frequency (< 5 MHz) power conversion systems as well as in RF (425 MHz) power amplifiers. The power BJTs for low frequency switching applications were designed to block 1300 V and showed a specific on-resistance of 8.0 mohm-cm2, which outperforms all SiC power switching devices ever reported. Moreover, these transistors show a positive temperature coefficient in the on-resistance and a negative temperature coefficient in the current gain, which enable easy paralleling of the devices. In addition, RF BJTs were designed, fabricated and tested for operation at UHF frequencies. The common emitter breakdown voltage was in excess of 500 V consistent with the 5 micron collector thickness. For VCC = 20 V, fT peaked at about 1.5 GHz. A single cell was measured in common emitter mode with a collector supply voltage of 80 V in class AB at 425 MHz. A 100 μs pulse width with 10% duty cycle was used. A maximum output power of 50 W for a single cell was achieved. The peak large signal power gain was 9.6 dB. The collector efficiency at the power output of 50 W was 51% with a power gain of 9.3 dB. This represents the first demonstration of a SiC RF BJT.

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