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:
Dec. 30, 2008
Filed:
Oct. 16, 2006
John Kenneth Fogg, Cary, NC (US);
Yin-chih Yang, Taipei, TW;
John Kenneth Fogg, Cary, NC (US);
Yin-Chih Yang, Taipei, TW;
Semtech Corporation, Morrisville, NC (US);
Abstract
In a switched mode power supply (SMPS) then selectively operates in continuous current mode (CCM) and discontinuous current mode (DCM), the minimum switching frequency of the SMPS is adjusted by setting a minimum duration for DCM operation. A resistance value applied to an external pin of the SMPS controls the duration of a timer that is reset in CCM and activated upon entering DCM. Upon expiration of the variable duration, the SMPS reverts to CCM for at least one switching cycle. This allows the SMPS minimum effective switching frequency to be set, for each application in which the SMPS is deployed, at a level that avoids audible noise (but which may be lower than an ultrasonic frequency), thus taking maximum advantage of the efficiencies of DCM operation under light load conditions.