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:
Jul. 21, 1998
Filed:
Nov. 27, 1996
Applicant:
Inventor:
Masato Nishikawa, Tokyo, JP;
Assignee:
NEC Corporation, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03L / ; H03L / ;
U.S. Cl.
CPC ...
331 17 ; 331 / ; 331-8 ; 331 16 ; 331 25 ; 327157 ; 327159 ; 455260 ;
Abstract
A phase lock loop includes a voltage controlled oscillator (VCO), a phase comparator for comparing the phases of the output of the VCO and a reference signal, a charge pump circuit, including a plurality of current sources, for supplying a control voltage by charging or discharging a capacitor based on the outputs of the current sources, and a current source controller for controlling the current output of the current sources by a n-bit current control signal. Charge current and discharge current by the charge pump circuit are controlled in n bits so that a rapid synchronization during lock-in and a low jitter after lock-in can be obtained.