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:
Jan. 30, 2001
Filed:
May. 26, 1998
Nick M. Johnson, Los Altos, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A system and method which generates amplified signals indicative of left and right stereo channels, and uses the signals to drive transducers for each of subwoofer, left stereo, and right stereo channels. The amplification circuitry is operable with a power supply having low peak current capability (i.e., low peak to average current rating) even when amplifying an input signal pair having highly correlated frequency components, since it spreads the peak current demands imposed on the power supply over a full cycle of each of the highly correlated frequency components. A series-connected pair of left and right channel transducers is driven by left and right channel power amplifiers of the amplification circuitry, and the subwoofer channel transducer is connected in parallel with this transducer pair so that all three transducers are driven by two power amplifiers, thus eliminating the need for a third power amplifier to drive the subwoofer channel transducer. Preferably, the system of the invention includes high pass and low pass filters which direct appropriate subsets of the frequency components of each output signals of the amplification circuitry outputs to an appropriate subset of the transducers.