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:
Jun. 28, 2011
Filed:
Jun. 29, 2009
Zhenyu Yang, Shanghai, CN;
Tianwei Liu, Shanghai, CN;
Zhenyu Yang, Shanghai, CN;
Tianwei Liu, Shanghai, CN;
Integrated Device Technology, Inc., San Jose, CA (US);
Abstract
A delta-sigma fractional-N frequency synthesizer having a charge pump with error canceling circuitry eliminates a non-linear term from the charge pump transfer function. The charge pump includes a matched pair of charging current sources, each supplying a first current Ito a common node, when enabled. The charge pump also includes a matched pair of discharging current sources, each sinking a second current Ifrom the common node, when enabled. The error canceling circuitry includes a charging current source, which supplies a current equal to the second current Ito the common node, when enabled. The error canceling circuitry also includes a discharging current source, which sinks a current equal to the first current Ifrom the common node, when enabled. The charging and discharging current sources of the error canceling circuitry are both enabled when either one of the matched pairs of charging and discharging current sources is enabled.