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.

Date of Patent:
Sep. 20, 2016

Filed:

Jan. 16, 2013
Applicants:

Daisuke Mita, Chiyoda-ku, JP;

Masaki Noda, Chiyoda-ku, JP;

Masamichi Nogami, Chiyoda-ku, JP;

Inventors:

Daisuke Mita, Chiyoda-ku, JP;

Masaki Noda, Chiyoda-ku, JP;

Masamichi Nogami, Chiyoda-ku, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03F 3/08 (2006.01); H03G 3/30 (2006.01);
U.S. Cl.
CPC ...
H03F 3/08 (2013.01); H03G 3/3084 (2013.01);
Abstract

A current bypass circuit that passes part of a photocurrent output from a photodetector is connected to an input terminal of a current-to-voltage conversion amplifier circuit. A voltage obtained by level conversion of an output voltage by a voltage level conversion circuit is input into the current bypass circuit so that the current bypass circuit is turned on at a photocurrent that is smaller than the photocurrent at which a diode connected in parallel to a feedback resistor of the current-to-voltage conversion amplifier circuit is turned on. Consequently, the current-to-voltage conversion gain is switched in three stages according to the intensity of the photocurrent corresponding to an optical signal level.


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