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:
May. 21, 2013
Filed:
Mar. 05, 2009
Takashi Takemoto, Fuchu, JP;
Hiroki Yamashita, Hachioji, JP;
Tatsuya Saito, Kunitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An optical communication device which can be operated at high speed is provided. For example, the optical communication device includes: a pre-amplifier circuit PREAMPamplifying a current signal Iin from a photodiode PD, and converting an amplified signal into a voltage signal; and an operating-point controller circuit VTCTLcontrolling an operation of the PREAMP. The PREAMPincludes a negative feedback path formed by a feedback resistance Rf, and includes: a level-shift circuit LSlevel-shifting in accordance with an operating-point control signal Vcon; and an amplifier circuit AMPconnected to a subsequent stage of the LSand performing an amplifying operation with a high gain. The VTCTLincludes a replica circuit configured by the same circuit and circuit parameter as those of the AMPand electrically connected between the input and the output, and generates the Vcon so that an output DC level of this replica circuit is matched with an input DC level of the AMP