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. 25, 2005
Filed:
Jan. 21, 2004
Richard Redl, Farvagny-le-Petit, CH;
Yuxin LI, Santa Clara, CA (US);
Gabor Reizik, Dublin, CA (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
A switched noise filter circuit for DC-DC converters which use the instantaneous output voltage to establish the converter's duty ratio. The converter cycles the switching element on and off for time intervals Tand T, respectively. A switching control circuit includes a filter capacitance connected between the feedback node and ground, and a comparator which compares a feedback voltage Vwith a fixed voltage V; at least one of Tand Tis a 'modulated' interval which is terminated when Vcrosses Vdue to the discharge of the filter capacitance. A switched noise filter circuit applies an offset voltage to Vduring at least one of T, and T, with the offset voltage disconnected from Vby the beginning of the modulated interval or shortly thereafter. When the offset voltage is properly applied, the effect of extraneous electromagnetic noise coupled into Vis reduced.