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. 05, 2008
Filed:
Jul. 03, 2006
Tetsuo Chato, Osaka, JP;
Hiroshi Yamaguchi, Osaka, JP;
Tetsuo Chato, Osaka, JP;
Hiroshi Yamaguchi, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
The present invention provides a light-receiving amplifier circuit which includes a clipping circuit, can prevent an oscillation at the time of clipping operation, and can freely set clipping voltage. The light-receiving circuit of the present invention includes a photodiode, an operation amplifier, a conversion resistance connected between an output terminal and an inverting input terminal of the operation amplifier, and a clipping circuit which clips output voltage of the operation amplifier to a predetermined value. The clipping circuit includes a PNP transistor which detects a change in the output voltage of the operation amplifier and a voltage source connected to a base of the PNP transistor. Here, when the PNP transistor is turned ON along with an increase of an emitter potential of the NPN transistor which constitutes an output amplifier stage of the operation amplifier, voltage from the voltage source is applied to the base of the NPN transistor via the PNP transistor.