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:
Jan. 10, 1978
Filed:
Oct. 14, 1975
Applicant:
Inventors:
Kosei Nomiya, Tokyo, JA;
Takao Tsuiki, Kokubunji, JA;
Assignee:
Hitachi, Ltd., , JA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
3151 / ; 307 33 ; 307 60 ; 307297 ; 307304 ; 315307 ; 323-4 ; 340336 ;
Abstract
A constant current driving circuit for driving light emitting diodes, wherein a variation detecting circuit comprising a resistor and a field effect transistor is provided and the output voltage of the detecting circuit is effectively used to control the variation of electric current which flows through the driving transistor.