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:
Mar. 26, 2002
Filed:
Feb. 09, 2000
Bryan Scott Rowan, Los Gatos, CA (US);
Louis Joseph Serrano, San Jose, CA (US);
Mantle Man-Hon Yu, San Jose, CA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A variable pulse pulse width modulation digital-to-analog converter comprising: an input code register to store a digital input code to be converted; a PWM decoder, coupled to the input code register, to convert the input code to a series of pulses; an output driver circuit coupled to the PWM decoder, wherein the output driver circuit generates an output signal comprising pulses of a high logic level and pulses of an intermediate logic level; and a filter to integrate the pulses to generate an analog output value corresponding to the digital input code. In one embodiment, the output stage comprises an active tri-state driver, a multiplexer and at least two output reference voltage sources. Using a plurality of different amplitude pulse levels enables PWM DACs according to the present invention to provide greater resolution than conventional PWM DACs for a given clock frequency and conversion period.