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:
Jan. 25, 2005
Filed:
May. 05, 2004
Gilles P. Denoyer, San Jose, CA (US);
Daniel Case, Gilroy, CA (US);
Gilles P. Denoyer, San Jose, CA (US);
Daniel Case, Gilroy, CA (US);
Finisar Corporation, Sunnyvale, CA (US);
Abstract
An optical component is provided that includes a detector configured to transmit an input current to a transimpedance amplifier that includes an automatic transimpedance gain control and DC cancellation control feedback circuit having variable impedance circuitry. Open loop gain of the feedback circuit is independent of the average input current as the input current increases. The feedback circuit includes first and second pnp transistors arranged so that their respective bases are connected and so that an emitter terminal of the first pnp transistor is connected to the input of the transimpedance amplifier, and the impedance seen at the emitter terminal changes according to the average value of the input current. The emitter size of the second pnp transistor is a factor N smaller than emitter size of the first pnp transistor. N can be selected to adjust the gain control and low corner frequency variation with input power.