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US 4,380,741 AGranted
Photocurrent compensation for electronic circuitry exposed to ionizing radiation
AssigneeRCA Corporation
InventorJames D. Mazgy
Life of this patent
Estimating the term…
Abstract
In one embodiment of the present invention, photocurrents induced in the collector-base junction of a transistor by ionizing radiation incident thereon are compensated by the photocurrent generated by a plurality of series-connected diodes. One feature of the invention includes the selection of the junction areas of the diodes relative to that of the transistor to obtain a predetermined potential at an electrode of the transistor during the incidence of the ionizing radiation.
Claims17
In combination:
- supply means for receiving an operating potential;
- a transistor having base, emitter and collector electrodes, and having a semiconductor junction between its collector and base electrodes;
- means including load means for coupling the base, emitter and collector electrodes of said transistor to said supply means to condition said transistor for conduction;
- and
- compensating means for conducting a current substantially equal to a photocurrent induced in the semiconductor junction of said transistor by ionizing radiation incident thereon including:
- a plurality of serially connected semiconductor junctions poled for conduction in like direction and responsive to said ionizing radiation for generating a compensating photocurrent substantially equal to said induced photocurrent;
- means coupling said supply means to one end of said plurality of serially connected semiconductor junctions to reverse bias said plurality of serially connected semiconductor junctions;
- and
- means for coupling the other end of said plurality of serially connected semiconductor junctions to one of the collector and base electrodes of the semiconductor junction of said transistor to make said compensating photocurrent flow with polarity sense opposite to that of said induced photocurrent.
6 more elements
In an electronic circuit including a transistor having collector and base electrodes and a semiconductor junction therebetween, and having an emitter electrode, and including means for coupling said collector, base and emitter electrodes to respective operating potentials,
- improved means for compensating a photocurrent induced in said semiconductor junction by ionizing radiation incident theren comprising:
- a plurality of serially connected diode means poled for conduction in like direction and responsive to said ionizing radiation for generating a compensating photocurrent;
- means coupling one of said respective operating potentials to one end of said plurality of serially connected diode means to reverse bias said plurality of serially connected diode means;
- and
- means connecting the other end of said plurality of serially connected diode means to one of the collector and base electrodes of said semiconductor junction for making said compensating photocurrent to flow with opposite polarity sense to that of said induced photocurrent.
2 more elements
In combination:
- a pair of transistor having respective emitter electrodes connected to a first node, and each having respective collector and base electrodes and respective semiconductor junctions therebetween;
- current supply means for supplying emitter current to said first node;
- means for applying respective signals to the respective base electrodes of said pair of transistors;
- load means to which the respective collector electrodes of said pair of transistors couple for withdrawing respective collector currents therefrom;
- and
- means for compensating first and second photocurrents induced in the respective semiconductor junctions of the first and second ones of said pair of transistors by ionizing radiation incident thereon including:
- first and second pluralities of diode means for generating respective first and second compensating photocurrents responsive to said incident ionizing radiation, the respective diode means of each of said first and second pluralities of diode means being connected in series and poled for conduction in like direction;
- first means for coupling said first plurality of diode means between the base electrode of the first one of said pair of transistors and a second node, said first plurality of diode means being poled for making said first compensating photocurrent of opposite polarity sense to that of said first induced photocurrent;
- second means for coupling said second plurality of diode means between the base electrode of the second one of said pair of transistors and said second node, said second plurality of diode means being poled for making said second compensating photocurrent of opposite polarity sense to that of said second induced photocurrent;
- and
- current conductive means coupled between said second node and a point of reference potential for conducting said first and second compensating photocurrents thereto.
8 more elements
Dependencies are inferred from the claim text.