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Radiation Resistant Voltage Gate

IP.com Disclosure Number: IPCOM000090507D
Original Publication Date: 1969-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Hixson, GD: AUTHOR

Abstract

This circuit provides a low-impedance path to a voltage supply or alternatively to ground and is radiation resistant. The circuit uses a clamp to prevent excessively large currents from flowing in the circuit during irradiation while introducing no current limiting components to raise circuit impedance. With the Input voltage at 0.0 volts, transistor Q1 is nonconducting which induces saturation in transistor Q3, thus clamping the Output to ground. With Q1 off, no base bias is available for transistor Q2, so that Q2 is also nonconducting. Q3 serves not only to hold the Output level close to volts, but also rapidly discharges any circuit capacitive loading. Q3 also absorbs any radiation induced leakage current from Q2. Radiation clamping is provided by the circuit elements within the dotted lines.

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Radiation Resistant Voltage Gate

This circuit provides a low-impedance path to a voltage supply or alternatively to ground and is radiation resistant. The circuit uses a clamp to prevent excessively large currents from flowing in the circuit during irradiation while introducing no current limiting components to raise circuit impedance. With the Input voltage at 0.0 volts, transistor Q1 is nonconducting which induces saturation in transistor Q3, thus clamping the Output to ground. With Q1 off, no base bias is available for transistor Q2, so that Q2 is also nonconducting. Q3 serves not only to hold the Output level close to volts, but also rapidly discharges any circuit capacitive loading. Q3 also absorbs any radiation induced leakage current from Q2. Radiation clamping is provided by the circuit elements within the dotted lines. Transistor Q4 is biased into saturation by the network consisting of R5, R6, and diode D10 and, therefore, clamps the base voltage of Q2 to the supply voltage. If the circuit is now irradiated in this state, Q4 prevents conduction in Q2. This action eliminates a potential low-impedance path from the collector of Q3 to the supply voltage during irradiation of the circuit, thus avoiding possible component damage in this path.

Diode D11 is used for radiation leakage compensation of Q2 and has no active part in normal circuit operation. D11 preferably consists of the collector- base junction of a transistor which is identical with Q2. The radia...