The Experts below are selected from a list of 2100 Experts worldwide ranked by ideXlab platform
A. Johnston - One of the best experts on this subject based on the ideXlab platform.
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The Effects of Space Radiation on Optocouplers
1998Co-Authors: A. JohnstonAbstract:Space radiation effects on Optocouplers are discussed, including permanent degradation from protons and electrons, and short-duration transients from protons and heavy ions. Proton displacement damage is shown to be the most important degradation mechanism, even for Optocouplers with radiation resistant light emitters. Amplifier design and light sensitivity both contribute to transient effects, which can persist for time periods of nearly one microsecond in some devices.
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TOPEX/Poseidon Radiation Issues: Displacement Damage in Optocouplers
1997Co-Authors: A. Johnston, G. SwiftAbstract:In this paper we describe observed failures of Optocouplers on the TOPEX/Poseidon (T/P) ocean measuring satellite. An indirect assessment is made of proton doses by the spacecraft, and these data are compared with laboratory proton irradiations of Optocouplers. It is shown that the T/P failures occur at expected doses for proton-induced displacement damage.
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topex poseidon radiation issues displacement damage in Optocouplers
1997Co-Authors: A. Johnston, G. SwiftAbstract:In this paper we describe observed failures of Optocouplers on the TOPEX/Poseidon (T/P) ocean measuring satellite. An indirect assessment is made of proton doses by the spacecraft, and these data are compared with laboratory proton irradiations of Optocouplers. It is shown that the T/P failures occur at expected doses for proton-induced displacement damage.
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.
G. Swift - One of the best experts on this subject based on the ideXlab platform.
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TOPEX/Poseidon Radiation Issues: Displacement Damage in Optocouplers
1997Co-Authors: A. Johnston, G. SwiftAbstract:In this paper we describe observed failures of Optocouplers on the TOPEX/Poseidon (T/P) ocean measuring satellite. An indirect assessment is made of proton doses by the spacecraft, and these data are compared with laboratory proton irradiations of Optocouplers. It is shown that the T/P failures occur at expected doses for proton-induced displacement damage.
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topex poseidon radiation issues displacement damage in Optocouplers
1997Co-Authors: A. Johnston, G. SwiftAbstract:In this paper we describe observed failures of Optocouplers on the TOPEX/Poseidon (T/P) ocean measuring satellite. An indirect assessment is made of proton doses by the spacecraft, and these data are compared with laboratory proton irradiations of Optocouplers. It is shown that the T/P failures occur at expected doses for proton-induced displacement damage.
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.