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:
Nov. 04, 2003
Filed:
Sep. 20, 2002
Kevin S. Donnelly, San Francisco, CA (US);
Thomas H. Lee, Cupertino, CA (US);
Tsyr-Chyang Ho, San Jose, CA (US);
Rambus Inc., Los Altos, CA (US);
Abstract
A phase detector is described that includes a load circuit that presents both a high differential impedance and a low common mode impedance. The load circuit is coupled to (1) a power supply and (2) a first node and a second node. The first and second nodes form an output of the phase detector. A capacitive circuit has (1) a first capacitor coupled to the first node and ground and (2) a second capacitor coupled to the second node and ground. A first circuit is coupled to the first and second nodes for detecting a phase difference between a first signal and a second signal. A second circuit is coupled to the first and second nodes for detecting the phase difference between the first and second signals and for minimizing phase detection error of the first circuit such that the phase difference between the first and second signals can be detected with minimized phase detection error. Each of the first and second circuits receives the first and second signals and a reference signal. The second circuit is cross-coupled to the first circuit such that an error current generated by the second circuit cancels that generated by the first circuit such that the phase detector detects the phase difference between the first and second signals with minimized phase detection error.