Patent ID: 7898324
Filing Date: 2011-03-01
Classification: H03F

Abstract:
1. An apparatus comprising: first and second amplifiers, each having an input coupled to an audio signal input and an output coupled to an audio signal output, the second amplifier also having a feedback path from its output to its input; a first switch coupled to the audio signal input, the input to the first amplifier, and a first node, where the first switch is operable to selectively couple and uncouple the audio signal input and the input to the first amplifier to and from the first node; a second switch coupled to the input to the second amplifier and to the first node, where the second switch is operable to selectively couple and uncouple the input to the second amplifier to and from the first node; and a third switch coupled to the first node and to ground, where the third switch is operable to selectively couple and uncouple the first node to and from ground.