Patent ID: 9237401
Filing Date: 2016-01-12
CPC Classification: H04R

Claim Text:
1. An electronic device in first and second modes of operation, comprising: audio codec circuitry; an audio connector that connects to an accessory and that comprises a microphone terminal and a microphone line; adjustable bias circuitry that generates an adjustable bias signal that is supplied to the accessory through the microphone line, wherein the adjustable bias circuitry provides the adjustable bias signal with a first impedance during the first mode in response to determining that microphone voice signals are being conveyed over the microphone line, and the adjustable bias circuitry provides the adjustable bias signal with a second impedance that is less than the first impedance during the second mode in response to determining that the microphone voice signals are not being conveyed over the microphone line, the adjustable bias circuitry comprising: