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Applying analog integrated circuits for HERO protectionOne of the most efficient methods for protecting electro-explosive devices (EED's) from HERO and ESD is to shield the EED in a conducting shell (Faraday cage). Electrical energy is transferred to the bridge by means of a magnetic coupling which passes through a portion of the conducting shell that is made from a magnetically permeable but electrically conducting material. This technique was perfected by ML Aviation, a U.K. company, in the early 80's, and was called a Radio Frequency Attenuation Connector (RFAC). It is now in wide use in the U.K. Previously, the disadvantage of RFAC over more conventional methods was its relatively high cost, largely driven by a thick film hybrid circuit used to switch the primary of the transformer. Recently, through a licensing agreement, this technology has been transferred to the U.S. and significant cost reductions and performance improvements have been achieved by the introduction of analog integrated circuits. An integrated circuit performs the following functions: (1) Chops the DC input to a signal suitable for driving the primary of the transformer; (2) Verifies the input voltage is above a threshold; (3) Verifies the input voltage is valid for a pre set time before enabling the device; (4) Provides thermal protection of the circuit; and (5) Provides an external input for independent logic level enabling of the power transfer mechanism. This paper describes the new RFAC product and its applications.
Document ID
Document Type
Conference Paper
Willis, Kenneth E.
(Quantic Industries San Carlos, CA United States)
Blachowski, Thomas J.
(Naval Surface Warfare Center Indian Head, MD United States)
Date Acquired
August 17, 2013
Publication Date
February 1, 1994
Publication Information
Publication: The 2nd NASA Aerospace Pyrotechnic Systems Workshop
Subject Category
Electronics And Electrical Engineering
Accession Number
Distribution Limits
Work of the US Gov. Public Use Permitted.
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