Patent ID: 7924091

Claim:
A circuit for driving an audio loudspeaker, comprising: an amplifier; an input resistor connected between an audio source and an input of the amplifier; a feedback network connected between an output of the amplifier and an input of the amplifier; a capacitor connected at a first terminal to a first terminal of the audio loudspeaker and a at a second terminal to a second terminal of the audio loudspeaker; a power switch adapted to provide drive current to the audio loudspeaker and connected between the output of the amplifier and the first terminal of the capacitor; a feedback resistor connected between the second terminal of the capacitor and the input of the amplifier; a sense resistor connected at a first terminal to the second terminal of the capacitor; and an inductor connected between a second terminal of the sense resistor and ground, where the capacitor (C) and the inductor (L) form a passive LC reconstruction filter having at least a portion of the passive LC reconstruction filter situated in a feedback loop of the amplifier and the circuit is adapted to operate in a current feedback mode as a voltage-controlled current source.