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. 17, 2010
Filed:
Aug. 21, 2008
Richard Ellis Jennings, Garland, TX (US);
MD Anwar Sadat, Plano, TX (US);
John Thomas Wilson, Allen, TX (US);
Richard Ellis Jennings, Garland, TX (US);
Md Anwar Sadat, Plano, TX (US);
John Thomas Wilson, Allen, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
In a method and apparatus for controlling damping and bandwidth in a phase locked loop (PLL), a loop filter is configured to have a dual path for charge pump current. A 3 dB bandwidth of the PLL is controlled by adjusting gain of a proportional current path. An integral current path includes a gating circuit to digitally control an amount of time an integral charge pump current received is passed through as an effective integral charge pump current. A resistor and capacitor (RC) circuit filters the proportional and effective integral charge pump currents, thereby providing a filtered input to a voltage controlled oscillator. Damping and hence peaking of the PLL is precisely controlled by sampling one of every p samples of the integral charge pump current to provide the effective integral charge pump current, p being an integer.