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. 09, 1998
Filed:
Oct. 09, 1996
Dennis Rose, Sunnyvale, CA (US);
Christian V Olgaard, Sunnyvale, CA (US);
Steve Lo, Menlo Park, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An apparatus for reducing the power consumed by, and the noise generated at the output of a charge pump which is part of a phase locked loop circuit. A reduction in the power consumed by the charge pump is achieved by synchronizing the powering up of the charge pump bias circuit to the state of the counters which control the timing of the signal which triggers a charge pump cycle. In this way current is supplied to the charge pump circuit only when needed for the operation of the pump. A reduction in the noise present at the output of the charge pump caused by the reloading of the counters while the pump is activated is achieved by loading a portion of the counter bits prior to activating the pump. A circuit detects when the counter is close to a value of zero and produces a signal which loads the most significant bits of the counter. When the counter reaches a value of zero, the remaining bits are loaded. This reduces the number of counter bits which are loaded while the pump circuit is active, thus reducing the switching noise present on the pump output.