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:
Dec. 12, 2006
Filed:
Feb. 18, 2005
Hon Kin Chiu, Hayward, CA (US);
Hon Kin Chiu, Hayward, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A charge pump-based PLL dynamically controls loop gain in response to the frequency of an input signal. The loop gain is dynamically adjusted by varying the bias current of the charge pump circuit of the PLL. The bias current is varied in response to the voltage of a loop filter that is coupled to the output of the charge pump circuit. A voltage-to-current converter ('V/I converter') converts the voltage of the loop filter to a current. The current is mirrored to a dynamic bias generator. The dynamic bias generator comprises a sample-and-hold circuit that is used to sample the mirrored current when the charge pump circuit is temporarily switched off. The sampled current level is used to adjust the level of the bias current of the charge pump circuit. The switching the charge pump off minimizes the disturbance of the loop filter voltage by the charge pump.