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. 09, 2007
Filed:
Sep. 10, 2004
Hong Sair Lim, Singapore, SG;
Junho Cho, Markham, CA;
Hong Sair Lim, Singapore, SG;
Junho Cho, Markham, CA;
FTD Solutions Pte, Ltd., Singapore, SG;
Abstract
A spread spectrum clock generator comprises a conventional closed-loop VCO and an open-loop VCO where both are coupled to the same point of the PLL. Both VCOs comprise a V-to-I converter followed by a current-controlled oscillator and are identical in design but only the open-loop VCO receives the modulation current to generate the spread spectrum clock signal. The open-loop ICO is part of the spread spectrum generator and in one embodiment of the invention receives feedback current signals representing the modulation method and modulation ratio. This ensures that the modulated clock output tracks the PLL output frequency. In a second embodiment the closed-loop VCO receives from the spread spectrum generator the feedback current signal representing the modulation method (center/down spread) while the open-loop VCO receives the feedback signal representing the modulation ratio.