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. 26, 2003
Filed:
Nov. 06, 2001
Ravi Kumar, Bangalore, IN;
Chandra P. Tiwari, Bangalore, IN;
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A charge sharing suppression circuit for a charge pump circuit in a phase locked loop is disclosed that is capable of suppressing charge sharing due to static phase error in the phase locked loop. A return path is provided to allow charge pump currents to flow when static phase error exists. A first switch in the return path closes in response to an UP signal from a phase frequency detector and a second switch closes in response to an inverted version of a DN signal. A third switch in the return path closes in response to an inverted version of an UP signal and a fourth switch closes in response to a DN signal. The return path is disabled in the absence of static phase error.