The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 18, 1987
Filed:
Oct. 22, 1984
Applicant:
Inventors:
Assignee:
Siemens Aktiengesellschaft, Berlin and Munich, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01L / ;
U.S. Cl.
CPC ...
357 41 ; 357 43 ; 307304 ; 307311 ; 307570 ;
Abstract
In a circuit arrangement having a phototransistor, in order to increase the inverse voltage strength of the phototransistor, a resistor that carries off the collector-base inverse current generally lies between the base zone and the emitter zone of the phototransistor. This resistor should be as large as possible given illumination in order to increase the current gain. The resistor according to the invention is formed by the drain-source path of an IGFET of depletion type whose gate terminal is at a fixed potential. The IGFET is conductive in the unilluminated condition of the phototransistor. During illumination, its resistance increases given an increasing photocurrent.