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:
Oct. 27, 1998
Filed:
Jan. 11, 1996
Mehrdad Nayebi, Palo Alto, CA (US);
Duc Ngo, San Jose, CA (US);
Sony Corporation, Tokyo, JP;
Sony Electronics, Inc., Park Ridge, NJ (US);
Abstract
An error regulator circuit for use within a charge pump circuit of a phase-locked loop monitors levels of the control signals used to control the charge pump circuit. When one of the control signals remains at a predetermined voltage level for a predetermined period of time, indicating that the charge pump circuit is in a hold mode or an inactive period of time, the current sources within the charge pump used to charge and discharge a charge pump capacitor are temporarily disabled. During a hold or inactive period when one of the control signals used to control the charge pump circuit remains at the predetermined voltage level for more than a predetermined period of time, the current sources of the charge pump circuit are disabled and the charge pump circuit is prevented from charging or discharging the charge pump capacitor until the current sources are re-enabled, thereby allowing the charge pump circuit to maintain an appropriate level of charge across the capacitor during an inactive or hold period. The current sources are re-enabled when the control signal which was at the predetermined voltage level for more than the predetermined period of time is no longer at the predetermined voltage level.