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, 1999
Filed:
Dec. 26, 1996
Randon Wayne Smith, Sunnyvale, CA (US);
Lee Stuart Tavrow, Sunnyvale, CA (US);
Mark Ronald Santoro, Sunnyvale, CA (US);
Micro Magic, Inc., Sunnyvale, CA (US);
Abstract
A phase locked loop (PLL) circuit includes a phase comparator that compares the phases of an input signal and a feedback signal and generates UP and DOWN pulses that are related to the phase difference. A charge pump receives the UP and DOWN pulses from the phase comparator and either charges or discharges the tuning voltage of a loop filter. The voltage controlled oscillator (VCO) provides an output signal that has a frequency that is related to the tuning voltage. A frequency divider then divides the frequency of the VCO output by a factor of N and provides the output as the feedback signal to the phase comparator. The PLL includes pre-lock circuitry that responds to an active state of a pre-lock input signal by narrowing the dynamic range of the VCO to a pre-lock range that is centered around a predetermined final frequency and that deactivates upon achieving the pre-lock range.