Stmicroelectronics Gmbh

Ravisent Technologies, Inc.

Thomas Joseph O'Brien

The invention provides a method and apparatus for the modulation of more than one channel of audio in a digital amplification system. In the preferred embodiment of the invention, pulse width modulator outputs are staggered in time such that at idle only one channel switches states at a time. This is done to provide an even draw from the power supply, assuming that the same supply is used for the multiple channels. For example, in a two channel system, the idle state of the pulse width modulator for the first channel is 90 degrees out of phase with the pulse width modulator output of the second channel.

Method and apparatus for multi-channel digital amplification

A digital input switching audio power amplifier uses a simple logic circuit and/or software program for signal processing and, therefore, does not require an expensive DSP processor. The invention provides an approach that allows the integration of power level meters and volume controls in the logic circuit. In one embodiment of the invention, the amplifier accepts multiple inputs, an active one of which may be digitally selected. The invention uses this novel approach to signal processing to achieve high performance. The invention also provides lower system cost as a result of the higher levels of system integration provided by the logic circuit. Increased system versatility results from a modular design which allows the production of an amplifier having optimum cost-to-performance ratios. The amplifier is implemented in ASIC and FPGA circuitry, such that a designer using the invention is provided with flexibility in choosing the various operating parameters of the amplifier, e.g. the amplifier is capable of operating at various power levels and of implementing various output stage topologies.

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Limerick, PA, United States of America

Thomas Joseph O'Brien