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, 2003
Filed:
Dec. 13, 1999
Helmut Lenz, Oberasbach, DE;
Christian Schwingenschloegl, Schwaig, DE;
Siemens Aktiengesellschaft, Münich, DE;
Abstract
A power amplifier, particularly a gradient amplifier of a nuclear magnetic resonance tomography apparatus, has at least one switched output stage containing a power bridge circuit formed by a number of switch elements, the bridge circuit being connected to a floating intermediate circuit voltage, as well as at least one digital pulse width modulator that generates pulse-width-modulated control signals for all switch elements of the power bridge circuit from digital input signals in order to generate at least one output stage voltage according to an output stage switching clock. The digital pulse width modulator has a modulator base element that contains a counter with an output for a counter reading, at least one comparator with an input for receiving the counter reading, a further input for receiving one of the digital input signals, an output binary signal representing a “smaller-than” comparison, and a further output for a further binary signal representing a “greater-than” comparison of the counter reading to the digital input signal. Circuitry follows the comparator for generating the control signals from the binary signals.