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:
Apr. 20, 2004
Filed:
Nov. 26, 2002
Johan Nilsson, Lund, SE;
Dialog Semiconductor GmbH, Kirchheim/Teck-Nabern, DE;
Abstract
A method to generate virtual multi-level output pulses for a Class-D Amplifier, where the time-voltage-area corresponds to a multiple of digital levels is achieved. A class-D Amplifier using PDM (Pulse Density Modulation) normally converts the input signal with a Sigma Delta Modulator into high-frequency pulses of equal width and typically drives an H-Bridge, with its 3 physical output levels. The disclosed invention however adds the methods to produce pulses with a multiple of discrete values of width and provides the method to generate a pulse length select control signal for these variable-width-pulses. Using multi-level pulse widths, in contrast to just a single pulse width, allows the reduction of the pulse-sampling rate by the same factor. Or Multi-level pulse widths allow a better quality output signal. In addition, better power efficiency is achievable.