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:
Aug. 01, 2006
Filed:
Jun. 30, 2004
Hon Kin Chiu, Hayward, CA (US);
Hon Kin Chiu, Hayward, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A gated phase-frequency detector circuit includes a phase-frequency detector and a multiplexer circuit. The phase-frequency detector is arranged to provide UP and DOWN signals responsive to a reference clock signal and a feedback signal. Further, the phase-frequency detector includes a first flip-flop that provides the UP signal, a second flip-flop that provides the DOWN signal, and a clear logic circuit. One input of the multiplexer circuit is coupled to the output of the first flip-flop, another input of the multiplexer circuit is arranged to receive a logic high signal, and an output of the multiplexer circuit is coupled to the D input of the first flip-flop. The multiplexer circuit is arranged to multiplex the logic high signal and the UP signal responsive to a reference gate signal. If the reference gate signal corresponds to an active level, logic level of the UP signal does not change.