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:
Jan. 02, 2001
Filed:
Sep. 01, 1999
Ravindra U. Shenoy, Sunnyvale, CA (US);
Xiaomin Si, San Jose, CA (US);
LSI Logic Corporation, Milpitas, CA (US);
Abstract
A system and method for a differential charge pump with reduced charge-coupling effects for use in integrated circuits such as a phase-lock loop are disclosed. The charge pump includes a first branch, a second branch, and a charge device. The first branch includes a first current source and sink coupled to a power supply and ground, respectively, a first current steering device coupled between the first current source and sink, and a first buffer coupled to the first current steering device between a first charge node and a first damp node. The second branch includes a second current source and sink coupled to a power supply and ground, respectively, a second current steering device coupled between the second current source and sink, and a second buffer coupled to the second current steering device between a second charge node and a second damp node. The charge device is coupled between the first buffer and the second buffer at the first and second charge nodes, the first and second buffers being adapted to vary voltages at the first and second damp nodes relative to voltages at the first and second charge nodes, respectively. Each of the current steering devices is adapted to selectively steer current from one of the first and second current sources through the charge device to one of the first and second current sinks.