The Experts below are selected from a list of 2073 Experts worldwide ranked by ideXlab platform
T.f. Miyahira - One of the best experts on this subject based on the ideXlab platform.
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Optocouplers: Fundamentals and Hardness Assurance for Space Applications
IEEE Transactions on Nuclear Science, 2009Co-Authors: Allan H. Johnston, Richard D. Harris, T.f. MiyahiraAbstract:Operating principles and hardness assurance methods are discussed for various types of Optocouplers. Radiation damage in light-emitting diodes is addressed, along with the impact of phototransistors and internal amplifiers on overall performance. Hardness assurance for Optocouplers is contrasted with the approach used for conventional microelectronics. Methods of detecting abnormal devices are discussed, along with the implementation of special screening measurements.
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Radiation Damage in Power MOSFET Optocouplers
IEEE Transactions on Nuclear Science, 2007Co-Authors: Allan H. Johnston, T.f. MiyahiraAbstract:Radiation damage is investigated in Optocouplers with power MOSFET output stages. They differ from conventional Optocouplers, incorporating an intermediate photovoltaic chip to allow the MOSFET gate voltage to be controlled by the light-emitting diode. These Optocouplers are sensitive to ionization as well as displacement damage, and can fail catastrophically from degradation in either the power MOSFET or the LED. Radiation testing must take both mechanisms into account.
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Hardness assurance methods for radiation degradation of Optocouplers
IEEE Transactions on Nuclear Science, 2005Co-Authors: Allan H. Johnston, T.f. MiyahiraAbstract:Hardness assurance methods are examined for several types of Optocouplers. A new diagnostic method using reverse-recovery time has a strong correlation with damage in the internal light emitting diode (LED). It depends only on electrical measurements, and can be used as a first-order parameter to determine LED properties when the LED technology of the Optocoupler is unknown, as well as for evaluating unit and lot variability. For devices with internal LEDs that are highly sensitive to displacement damage, the dependence of phototransistor gain on operating conditions can impact post-radiation performance. For devices with radiation-tolerant LEDs, phototransistor characteristics and gain degradation are both important in determining the net effect of displacement damage.
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Trends in Optocoupler radiation degradation
IEEE Transactions on Nuclear Science, 2002Co-Authors: T.f. Miyahira, Allan H. JohnstonAbstract:Proton-radiation test results for new Optocoupler technologies are compared with those of older Optocouplers. The new devices are far more resistant to displacement damage effects and have a much higher current-transfer ratio (CTR). The improvements are due to improved optical-coupling efficiency in combination with light-emitting diode (LED) technologies that are inherently more resistant to lifetime degradation. Because of these changes, CTR degradation is no longer dominated by LED damage. LED degradation, gain degradation, and photoresponse degradation all contribute to the overall changes in CTR after irradiation in the newer device types.
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Single-event upset effects in Optocouplers
IEEE Transactions on Nuclear Science, 1998Co-Authors: A.h. Johnston, T.f. Miyahira, Gary Swift, Steven M. Guertin, L.d. EdmondsAbstract:Single-event upset is investigated for Optocouplers using heavy ions. The threshold LET for Optocouplers with internal high-gain amplifiers is very low, causing output transients to occur even when the Optocouplers are irradiated with short-range alpha particles. Although previous work with high-energy protons showed that transients were caused by charge collected in the large-area photodetector, transients generated in the high-gain amplifier make a significant contribution to the total cross section when Optocouplers are irradiated with heavy ions. The transient pulse width increases with LET, exceeding 400 ns for long-range particles above 7 MeV-cm/sup 2//mg. This is about an order of magnitude greater than the pulse width that occurs when they are irradiated with protons. The ion range must exceed 50 /spl mu/m to characterize the cross section and pulse width in these devices.
M M Jovanovic - One of the best experts on this subject based on the ideXlab platform.
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Small-signal analysis and control design of isolated power supplies with Optocoupler feedback
IEEE Transactions on Power Electronics, 2005Co-Authors: Y Panov, M M JovanovicAbstract:Optocouplers are widely used in isolated power supplies to transfer the feedback signal from the secondary to the primary side. In many power supplies, the feedback amplifier is supplied from the output voltage that creates additional feedback path which should be taken into account in the control design. The paper presents a detailed analysis and control design for each of the two possible feedback loops that can be identified. In addition, dynamic limitations of the TL431 shunt regulator and of the Optocoupler are discussed. Practical guidelines for the error amplifier design and a design example are presented for both voltage-mode and current-mode controls.
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small signal analysis and control design of isolated power supplies with Optocoupler feedback
Applied Power Electronics Conference, 2004Co-Authors: Y Panov, M M JovanovicAbstract:Optocouplers are widely used in isolated power supplies to transfer the feedback signal from the secondary to the primary side. In many power supplies, the feedback amplifier is supplied from the output voltage that creates additional feedback path, which should be accounted in the control design. The paper compares two possible loop gains corresponding to breaking the feedback loop at different locations. These loop gains are analyzed and are shown to have an unequal value for the design. Dynamic limitations of the TL431 shunt regulator and the Optocoupler are discussed. Practical guidelines for the error amplifier design and a design example are presented.
Allan H. Johnston - One of the best experts on this subject based on the ideXlab platform.
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Optocouplers: Fundamentals and Hardness Assurance for Space Applications
IEEE Transactions on Nuclear Science, 2009Co-Authors: Allan H. Johnston, Richard D. Harris, T.f. MiyahiraAbstract:Operating principles and hardness assurance methods are discussed for various types of Optocouplers. Radiation damage in light-emitting diodes is addressed, along with the impact of phototransistors and internal amplifiers on overall performance. Hardness assurance for Optocouplers is contrasted with the approach used for conventional microelectronics. Methods of detecting abnormal devices are discussed, along with the implementation of special screening measurements.
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Radiation Damage in Power MOSFET Optocouplers
IEEE Transactions on Nuclear Science, 2007Co-Authors: Allan H. Johnston, T.f. MiyahiraAbstract:Radiation damage is investigated in Optocouplers with power MOSFET output stages. They differ from conventional Optocouplers, incorporating an intermediate photovoltaic chip to allow the MOSFET gate voltage to be controlled by the light-emitting diode. These Optocouplers are sensitive to ionization as well as displacement damage, and can fail catastrophically from degradation in either the power MOSFET or the LED. Radiation testing must take both mechanisms into account.
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Hardness assurance methods for radiation degradation of Optocouplers
IEEE Transactions on Nuclear Science, 2005Co-Authors: Allan H. Johnston, T.f. MiyahiraAbstract:Hardness assurance methods are examined for several types of Optocouplers. A new diagnostic method using reverse-recovery time has a strong correlation with damage in the internal light emitting diode (LED). It depends only on electrical measurements, and can be used as a first-order parameter to determine LED properties when the LED technology of the Optocoupler is unknown, as well as for evaluating unit and lot variability. For devices with internal LEDs that are highly sensitive to displacement damage, the dependence of phototransistor gain on operating conditions can impact post-radiation performance. For devices with radiation-tolerant LEDs, phototransistor characteristics and gain degradation are both important in determining the net effect of displacement damage.
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Trends in Optocoupler radiation degradation
IEEE Transactions on Nuclear Science, 2002Co-Authors: T.f. Miyahira, Allan H. JohnstonAbstract:Proton-radiation test results for new Optocoupler technologies are compared with those of older Optocouplers. The new devices are far more resistant to displacement damage effects and have a much higher current-transfer ratio (CTR). The improvements are due to improved optical-coupling efficiency in combination with light-emitting diode (LED) technologies that are inherently more resistant to lifetime degradation. Because of these changes, CTR degradation is no longer dominated by LED damage. LED degradation, gain degradation, and photoresponse degradation all contribute to the overall changes in CTR after irradiation in the newer device types.
B G Rax - One of the best experts on this subject based on the ideXlab platform.
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proton damage in micropac 66183 300 Optocoupler
European Conference on Radiation and Its Effects on Components and Systems, 2018Co-Authors: Farokh Irom, Gregory R Allen, Larry Edmonds, B G RaxAbstract:This paper reports proton damage in the Micropac 66183–300 Optocoupler and investigates the radiation degradation of the Optocoupler current transfer ratio (CTR) and transistor gain, HFE. We present statistical analysis using a one-sided tolerance method on the Optocoupler CTR data.
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A Method to Separate Proton Damage in LED and Phototransistor of Optocouplers
IEEE Transactions on Nuclear Science, 2018Co-Authors: Farokh Irom, Gregory R Allen, Larry Edmonds, B G RaxAbstract:This paper reports proton damage in light-emitting diode (LED) and phototransistor of the Micropac 66296 Optocoupler. Our results show that the Optocoupler current transfer ratio (CTR) data are influenced by the gain of the phototransistor. Analysis of the test data reveals interesting information, such as the dependence of the phototransistor gain on irradiation and photocurrent. Only a small reduction of phototransistor gain is observed with increasing irradiation when the irradiation is sufficiently large. The phototransistor gain reduction is more significant when comparisons are made with the unirradiated case. Statistical analysis is performed, using a one-sided tolerance method, on the LED light intensity and the Optocoupler CTR data. Mean and statistically derated values of the Optocoupler CTR and the LED light intensity data at room temperature are presented.
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Proton damage in LED and phototransistor of micropac 66179 Optocoupler
2016 16th European Conference on Radiation and Its Effects on Components and Systems (RADECS), 2016Co-Authors: Farokh Irom, Gregory R Allen, Larry Edmonds, B G RaxAbstract:This paper reports proton damage in LED and phototransistor of the Micropac 66179 Optocoupler. Analysis of the test data reveals interesting information, such as the dependence of the transistor gain on irradiation and photocurrent.
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Proton damage in linear and digital Optocouplers
IEEE Transactions on Nuclear Science, 2000Co-Authors: A.h. Johnston, B G RaxAbstract:Fundamental differences in design influence the way that linear and digital Optocouplers are degraded by radiation. Linear Optocouplers are more affected by current drive conditions because the detector operates in a high-injection region when the LED produces normal light output, and do not have the extra operating margin that is inherent in digital Optocouplers. Although LED degradation is often the dominant degradation mechanism in space environments, degradation of Optocouplers with improved LEDs is limited by photoresponse degradation. Phototransistor gain has a relatively minor effect except at very high radiation levels.
Han Jianwei - One of the best experts on this subject based on the ideXlab platform.
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Experimental Study on Single Event Transients of 4N49 Optocoupler
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2010Co-Authors: Ma Yingqi, Feng Guoqiang, An Guangpeng, Zhang Zhenlong, Huang Jian-guo, Han JianweiAbstract:The single event transient (SET) effect of the 4N49 Optocoupler was tested by pulsed laser experimental methodology.The characteristic of SET as amplitude and width was qualitatively investigated with the simulation of pulsed laser.A liner energy transfer (LET) threshold of 10 MeV·cm2·mg-1 was measured when the bias voltage was 10 V.The saturated SET cross-section is about 1.2×10-3 cm2.The SET effect of 4N49 Optocoupler on the following digital gate circuit was validated.The circuit-level design technique for mitigation of SET is reasonable and effective,and the threshold LET of 7.89 MeV·cm2·mg-12 can be improved to 22.19 MeV·cm2·mg-1.The experiment study on the SET of 4N49 Optocoupler provides an appropriate methodology to the SET test of the optics and their hardness assurance.
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Pulsed laser evaluation of single event transients in Optocouplers
TENCON 2009 - 2009 IEEE Region 10 Conference, 2009Co-Authors: Ma Yingqi, Feng Guoqiang, Han JianweiAbstract:A methodology which used pulsed laser to evaluate the Single Event Transients (SETs) in the Optocouplers was proposed. The SETs responses of the Optocouplers were firstly investigated with the experimental simulation by pulsed laser test facility. The pulsed laser test data was compared with the ion test data to indicate the veracity and to provide insights into the SETs mechanism. The SETs characters induced by pulsed laser were qualitatively analyzed in model theory.
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Study of Single Event Transients Effect for Optocoupler
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2008Co-Authors: Han JianweiAbstract:The single event transient(SET)effects of Optocoupler HCPL-5231 and HP6N134 were qualitatively investigated with single event effects simulation by pulsed laser test facility.The relation between transient pulse shape and pulsed laser equivalent LET was tested.The amplitude and duration of transients of both devices are increasing as equivalent LET raises.Then the sensitive areas of the SET effects were identified and the mechanism was initially analyzed.The relation between Optocoupler SET width and equivalent LET value was tested by pulsed laser.And the SET cross-section was measured with automatical scanning by laser test facility.The cross-section results of Optocoupler for HCPL-5231 are in good agreement with heavy ion data.