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, 2002
Filed:
May. 01, 2001
Kim Yeow Wong, Renton, WA (US);
David Lindsay Broughton, Tacoma, WA (US);
Jeffrey Mark Huard, Puyallup, WA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
Oscillator control circuitry for a phase lock loop, including phase detection circuitry, control signal generator circuitry, bias control circuitry and charge pump circuitry. The control signal generator circuitry introduces specific and distinct time delays to the phase signals from the phase detection circuitry representing the phase difference between the reference and oscillator output signals. These time delays cause the bias control circuitry to enable and disable the output charge pump circuitry slightly before and after, respectively, those time intervals during which an output source (“pump up”) or sink (“pump down”) current is needed to drive the oscillator via the loop filter. This produces charge pump circuitry output signals with significantly faster rise and fall times and shorter pulse widths, thereby resulting in a charge pump output signal with higher SNR and reduced spurious signal energy.