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:
May. 14, 1991
Filed:
Feb. 15, 1990
Bertrand J Williams, Campbell, CA (US);
Ronald L Treadway, Saratoga, CA (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
A PLL architecture is disclosed which incorporates a coarse adjustment feedback loop and a fine adjustment feedback loop together providing a combined error signal to a single VCO. The coarse adjustment feedback loop includes two digital counters set to divide the VCO output frequency by two different numbers. The outputs of the counters are coupled to the inputs of respective phase-frequency detectors, and the pump-up output of one of the detectors and the pump-down output of the other detector are used as the coarse adjustment pump-up and pump-down signals, respectively, in the coarse adjustment feedback loop. The coarse adjustment feedback loop thereby establishes a frequency range limitation for the fine adjustment feedback loop.