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:
Apr. 29, 2014
Filed:
Sep. 13, 2012
Chun Geik Tan, Singapore, SG;
Renliang Zheng, Singapore, SG;
Tieng Ying Choke, Singapore, SG;
MediaTek Singapore Pte. Ltd., Solaris, Singapore, SG;
Abstract
A differential ring oscillator includes a plurality of delay stages connected in a ring. At least one of the delay stages includes: a current source, arranged to generate a bias current according to a coarse tuning signal; a latching circuit arranged to generate a differential output signal to a next delay stage according to a differential input signal from a previous delay stage; a capacitive array arranged to provide a first capacitance according to a fine tuning signal; and a varactor device arranged to provide a second capacitance according to a controllable signal for locking an oscillating frequency of the differential ring oscillator to a target frequency. The coarse tuning signal and fine tuning signal are arranged for adjusting the oscillating frequency of the differential ring oscillator to, respectively, reach a predetermined frequency range including the target frequency and to approach the target frequency in the predetermined frequency range.