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:
Apr. 06, 1993
Filed:
Aug. 30, 1991
Tomokazu Kitajima, Kawasaki, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
An LED and a photo-diode are arranged such that they are optically coupled with each other. The first terminal to which a power supply voltage is applied is connected to the anode of the LED. Between the cathode of the LED and the second terminal for outputting an output signal, there is provided a constant current circuit for allowing a constant current to flow into the LED. To the cathode of the LED, connected is the collector of an NPN transistor, to the emitted of which the second terminal is connected. Light emitted from the LED is detected and converted into an current signal by the photo-diode. The current signal generated by the photo-diode is amplified by an amplifying circuit. A signal output from this amplifying circuit is supplied to the base of the NPN transistor, thereby controlling ON/OFF operation of the transistor. Between the second terminal and the ground point located outside the device, connected is a load resistor.