QUALCOMM Incorporated
Board-level noise reduction during headphone load current sensing

Abstract:

An audio codec system includes an audio driver path coupled to a first node of the audio codec system. A first terminal of a sense resistor external to the audio codec system is coupled to the first node and a second terminal of the sense resistor is coupled to an auxiliary device load. The audio codec system includes a second path having a first bias circuit, a second bias circuit and an off-chip voltage reference. The first bias circuit is coupled to a second node of the audio codec system. The second bias circuit is coupled to a third node of the audio codec system. The off-chip voltage reference is associated with the auxiliary device load coupled between the first bias circuit and the second bias circuit.