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. 23, 2003
Filed:
Apr. 04, 2002
Control circuit for phase-locked loop (pll) with reduced cycle slip during acquisition of phase lock
Jeffrey Huard, Puyallup, WA (US);
Wayne Porter, Colorado Springs, CO (US);
David Broughton, Tacoma, WA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A circuit for controlling a phase-locked loop (PLL) with reduced cycle slip during acquisition of phase lock includes frequency dividers with selectable divisors for the reference and feedback signals, and a phase detector having a charge pump output circuit with selectable output current ranges. During acquisition of phase lock by the PLL, the divisors for the reference and feedback signal frequency dividers are increased by the same factor, and the charge pump current range is increased by the same ratio. As a result, the reference rate is decreased as the charge pump current range is increased simultaneously by the same ratio. Meanwhile, the linear loop bandwidth and phase margin remain substantially constant.