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. 31, 2012
Filed:
Mar. 03, 2010
Chung-zen Chen, Hsinchu, TW;
Chung-Zen Chen, Hsinchu, TW;
Elite Semiconductor Memory Technology Inc., Hsinchu, TW;
Abstract
A method for tracking a delay locked loop (DLL) clock is described. An external clock signal is allowed to pass through delay cells of a DLL during a first period of the external clock signal when a transition edge of a track signal applied on the DLL occurs. Then, when a transition edge of a sensing signal applied on the DLL occurs at a start of a second period of the external clock signal, the external clock signal is inhibited to pass through the delay cells and the number of the delay cells through which the external signal pass during the first period of the external clock signal is counted. When a reset signal is asserted, a delay time of each delay cell is reset such that a ratio of the delay time to the period of the external clock signal is kept from 10% to 15%.