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High-Voltage Power Supply With Fast Rise and Fall TimesA special-purpose high-voltage power supply can be electronically switched on and off with fast rise and fall times, respectively. The output potential is programmable from 20 to 1,250 V. An output current of 50 A can be sustained at 1,250 V. The power supply was designed specifically for electronically shuttering a microchannel plate in an x-ray detector that must operate with exposure times as short as 1 ms. The basic design of the power supply is also adaptable to other applications in which there are requirements for rapid slewing of high voltages. The power-supply circuitry (see figure) includes a preregulator, which is used to program the output at 1/30 of the desired output potential. After the desired voltage has been set, the outputs of a pulse width modulator (PWM) are enabled and used to amplify the preregulator output potential by 30. The amplification is achieved by use of two voltage doublers with a transformer that has two primary and two secondary windings. A resistor is used to limit the current by controlling the drive voltage of two field-effect transistors (FETs) during turn-on of the PWM. A pulse transformer is used to turn on four FETs to short-circuit four output capacitors when the outputs of the PWM have been disabled. The most notable aspects of the performance of the power supply are a rise time of only 80 s and a fall time of only 60 s at a load current of 50 A or less. Another notable aspect is that the application of a 0-to-5-V square wave to a shutdown pin of the PWM causes the production of a 0-to-1,250-V square wave at the output terminals.
Document ID
20100011184
Acquisition Source
Marshall Space Flight Center
Document Type
Other - NASA Tech Brief
External Source(s)
http://www.techbriefs.com/component/content/article/2492
Authors
Bearden, Douglas B. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Acker, Richard M. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Kapuslka, Robert E. (NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 24, 2013
Publication Date
December 1, 2007
Publication Information
Publication: NASA Tech Briefs, December 2007
Subject Category
Man/System Technology And Life Support
Report/Patent Number
MFS-31912-1
Distribution Limits
Public
Copyright
Public Use Permitted.

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IDRelationTitle20100011149Collected WorksNASA Tech Briefs, December 2007
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