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:
Dec. 08, 2009
Filed:
Jan. 14, 2005
Ramsin M. Ziazadeh, San Jose, CA (US);
Jitendra Mohan, Santa Clara, CA (US);
Ramsin M. Ziazadeh, San Jose, CA (US);
Jitendra Mohan, Santa Clara, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A driver for a vertical-cavity surface emitting laser (VCSEL) is provided that includes a bias current source, a modulation current source, and an output tracking circuit. The bias current source is operable to generate a bias current and an output voltage for the VCSEL and to generate a replica output voltage. The modulation current source is coupled to the bias current source by at least one switch and is operable to generate a modulation current for the VCSEL when the switch is closed. The output tracking circuit is coupled to the bias current source. The output tracking circuit is operable to generate a feedback signal for the bias current source based on the output voltage and the replica output voltage. The bias current source is also operable to generate the output voltage and the replica output voltage based on the feedback signal.