Multi-standard headset support with integrated ground switching

A system for detecting a configuration of a headphone jack, the system comprising:

• a first plurality of switches configured to couple a first headphone jack position to ground;
• a second plurality of switches configured to couple a second headphone jack position to ground;
• a microphone bias circuit comprising a high voltage threshold input, a low voltage threshold input, and a comparator selectively receiving the high voltage threshold, the low voltage threshold and a microphone bias signal, the microphone bias circuit configured to apply a microphone bias signal to the second headphone jack position when the first headphone jack position is coupled to ground, and for applying the microphone bias signal to the first headphone jack position when the second headphone jack position is coupled to ground;
• and
• a jack sense system for actuating the microphone bias circuit after detecting an insertion of the headphone jack;
• wherein the microphone bias circuit includes a voltage divider network generating a reference voltage used for determining a type of headphone jack after detecting the insertion of the headphone jack, and an s-shaped ramp generator configured to selectively ramp up the microphone bias signal and ramp down the microphone bias signal, and
• wherein the microphone bias circuit is further configured to bypass the s-ramp generator when the voltage of the microphone bias signal is detected to be greater than the high voltage threshold input during ramp-up, and switch the input to the comparator microphone bias circuit to the low voltage input.