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Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
simulator silicon controlled rectifier (SCR) a current controlled four-layer (pnpn) device for high power (3000 A) and low speed (500 Hz) applications. SCRs can only be on or off, with no intermediate operating states like transistors. The SCR acts as a switch that is turned on by a short current pulse to the gate, provided that the device is in its forward blocking state. Once latched on, the gate current can be removed and the device will remain on until the anode current goes negative, or the current through the SCR becomes less than its designated holding current. A disadvantage is that a commutation circuit is often needed for forced turn-off (forced commutation). an amorphous comsilicon dioxide (SiO2 ) pound of silicon and oxygen with a resistivity of 1014 to 1017 ohm-cm and a bandgap of 8.1 eV. Essential as a dielectric and insulator for silicon devices. silicon nitride (SiN4 ) for a semiconductor manufacturing process, a compound formed of silicon and nitrogen that is deposited and etched back to provide a masking layer appropriate for withstanding subsequent high temperature processing such as oxidation. SIMD See single-instruction stream, multipledata stream. similarity between symbol strings tance between symbol strings. See disa nonsingular matrix M such that P1 -Q 1 C1 D1 = M -1 0 0 I P2 -Q 2 C2 D2 M0 0I
ESD Design and Optimization in Advanced CMOS SOI Technology
Published in Juin J. Liou, Krzysztof Iniewski, Electrostatic Discharge Protection, 2017
SCR is another widely used ESD structure in advanced CMOS technologies for on-chip ESD protection. Advantages of SCR devices include high-current conduction, low DC leakage, and low parasitic capacitance. In addition, when used in I/O ESD protection, unlike the diode-based scheme, SCRs can discharge ESD current from I/O to ground rail directly, without relying on the low-power bus resistance to achieve adequate clamping voltage. Extensive silicon results of SCR design and optimization in advanced bulk CMOS technologies have been presented in various publications [13–15]. However, due to the unique device features in SOI, the same design of SCR implemented in bulk CMOS cannot be transferred to SOI technology directly [16–19]. The SCR device built in an SOI technology has the unique characteristics including: The lateral PNPN structure formed in a thin silicon filmNo existing parasitic devices to substrateLateral body contact scheme for cross-coupled PNP and NPNIsolation between external triggering circuits and main SCR
Converters for SRM Drives
Published in R. Krishnan, Switched Reluctance Motor Drives, 2017
The disadvantages include: An SCR is always in the current conduction path, thus increasing the losses in the converter and requiring a larger heatsink for cooling. This would further reduce the system efficiency much more noticeably in low-power SRM drives than in high-power SRM drives.Parts count is higher due to SCR gate drive amplifiers with their own isolation requirements.
Reconfiguration of an Electrothermal-Arc Plasma Source for In Situ PMI Studies
Published in Fusion Science and Technology, 2021
E. G. Lindquist, T. E. Gebhart, D. Elliott, E. W. Garren, Z. He, N. Kafle, C. D. Smith, C. E. Thomas, S. J. Zinkle, T. M. Biewer
The electrothermal source was developed with a spark gap switch. However, these switches can be unreliable with missed or delayed plasma pulses. The PDP Nd:YAG laser pulse is 10 ns full-width at half-maximum (FWHM) at 10 Hz, and the DH camera acquisition is limited to 500 Hz for 1-s duration. Hence, if a shot is delayed, the TS laser (if triggered via the spark gap signal) could completely miss the pulse and the DH camera frame would occur at an uncontrolled time relative to the plasma impact on the target. This complicates first-exposure experiments. Therefore, the spark gap switch will be replaced in future work with a silicon-controlled rectifier (SCR) thyristor, which is expected to be more reliable.