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:
Oct. 24, 2000
Filed:
Aug. 11, 1998
Naruichi Yokogawa, Kashihara, JP;
Takanori Okuda, Kashiba, JP;
Takayuki Shimizu, Kitakatsuragi-gun, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A light receiving amplifying device includes a light receiving device for outputting a light signal current which varies with a quantity of received light, a load resistor connected with the light receiving device in series, for generating a detected voltage which varies with the light signal current, and a low frequency current bypass circuit for preventing the detected voltage from being saturated when the detected voltage has a frequency in a low frequency band. The low frequency current bypass circuit is connected with the load resistor in parallel and has an input impedance varying with a frequency of the detected voltage. The device further includes a transimpedance amplifying circuit (inverting amplifying circuit) for transforming an impedance of the detected voltage, and a capacitor for coupling the low frequency current bypass circuit and the transimpedance amplifying circuit (inverting amplifying circuit). This makes it possible, with a relatively simple circuit and arrangement in an infrared communication receiver, to lower noises of the light receiving amplifying device while maintaining an operational range with respect to a DC photoelectric current.