Method and apparatus for an integrated headset switch with reduced crosstalk noise

摘要

An integrated audio signal processing circuit is described for reducing crosstalk noise in an integrated headset switch for a headset having two speakers, a microphone sharing a common ground. The audio signal processing circuit includes two audio amplifiers and also has two terminals configured to be either a microphone connection terminal or a headset ground connection terminal, respectively, depending on the type of the headset. An audio amplifier reference node is coupled to inputs of the audio amplifiers. The audio signal processing circuit has a first switch device responsive to a headset ground selection signal and configured to connect the audio amplifier reference node to the detected headset ground connection terminal. The audio signal processing circuit also has a second switch device responsive to the headset ground selection signal and configured to couple the detected headset ground connection terminal to a ground terminal of the audio processing circuit.

主权项

1. An audio signal processing circuit, comprising:
first, second, third, and fourth terminals for coupling to a headset having a first and a second speakers, a microphone, and a headset ground, wherein the first and the second terminals are configured for providing a first and a second audio signals to the first and the second speakers, respectively, wherein the third and the fourth terminals are configured to be either a microphone connection terminal or a headset ground connection terminal, respectively, depending on the type of the headset; an audio jack detection circuit configured to detect the headset ground connection terminal and to provide a corresponding headset ground selection signal; first and second audio amplifiers for providing the first and the second audio signals to the first and second terminals, respectively; an audio amplifier reference node coupled to inputs of the first and the second audio amplifiers for providing a common mode signal; a first switch device responsive to the headset ground selection signal and configured to connect the audio amplifier reference node to the detected headset ground connection terminal; a second switch device responsive to the headset ground selection signal and configured to couple the detected headset ground connection terminal to a ground terminal of the audio processing circuit; a third switch device responsive to the headset ground selection signal and configured to couple the microphone connection terminal to a microphone bias circuit; and a fourth switch device responsive to the headset ground selection signal and configured to couple the microphone connection terminal to a push button signal detection circuit.