Patent 7733174 was granted and assigned to Texas Instruments on June, 2010 by the United States Patent and Trademark Office.
An apparatus is provided. The apparatus includes an amplifier, differential amplifiers, and FETs. The amplifier has an intermediate node and an output node, and the amplifier is adapted to receive an audio signal. Each differential amplifier amplifies the difference between an output voltage from the output node with a reference voltages. The FETs are coupled in series with one another between a first and a second voltage, and each FET receives an output from at least one of the differential amplifiers. Additionally, the intermediate node is coupled to a node between at least two FETs.