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:
Jul. 27, 2010
Filed:
Dec. 18, 2008
Anna Wing Wah Wong, Santa Clara, CA (US);
Richard William Swanson, San Jose, CA (US);
Anna Wing Wah Wong, Santa Clara, CA (US);
Richard William Swanson, San Jose, CA (US);
Xilinx, Inc., San Jose, CA (US);
Abstract
A method of startup for a phase-locked loop (PLL) can include, at initiation of the PLL, providing a reference voltage from a startup voltage source to an input of a voltage controlled oscillator (VCO) in the PLL, wherein the reference voltage is set to a predetermined minimum voltage. The reference voltage can be stepwise increased from the predetermined minimum voltage. A frequency of a reference signal input to the PLL can be compared with a frequency of a feedback signal originating from an output of the VCO of the PLL to determine a frequency differential as the reference voltage increases. A determination can be made as to whether a convergence criterion is met according to the frequency differential. While the convergence criterion is not met, the reference voltage can be increased. When the convergence criterion is met, the reference voltage provided by the startup voltage source can be replaced with a voltage generated by an operational voltage source.