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. 08, 1991
Filed:
Oct. 12, 1990
Barry N Carroll, The Woodlands, TX (US);
Jean H Ho, The Woodlands, TX (US);
Compaq Computer Corporation, Houston, TX (US);
Abstract
A capacitor connected directly across the terminals of the primary inductance of a transformer of a switched mode power supply and a separately wound inductor connected between the primary inductance and the switching power transistor which form a lossless snubber circuit. The snubber circuit is more efficient since resistors are not used to dissipate the energy as unwanted heat. The capacitor increases the transistor turn off voltage rise time, thereby reducing radiated emissions. The inductor reduces emissions appreciably by absorbing the ringing that would otherwise occur after the transistor is turned fully off and increases the transistor turn on time.