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:
Sep. 21, 2004
Filed:
Apr. 09, 2002
Yoshitaka Hirai, Tokyo, JP;
NEC Electronics Corporation, Kanagawa, JP;
Abstract
There is provided a lock detection circuit for optimizing a lock detection time and an unlock detection time of a PLL circuit. The present invention has counters and for inputting and counting feedback signals and reference signals inputted to a phase comparator of a PLL circuit ; a comparison circuit for inputting and comparing count values of the counters and and outputting a control signal in an active state when the count value of the counter is a first value and the count value of the counter is the first value; a counter for counting the feedback signals when the control signal outputted from the comparison circuit is active; and a decision circuit for outputting an output signal of a value showing a lock state when a count value of the counter reaches a second value. The comparison circuit resets the counter when the count value of the counter is the first value and the count value of the counter is not the first value.