Maxim Integrated Products, Inc.
Systems and methods for accessory and impedance detection

Abstract:

Described herein are systems and methods for reliably detecting of the presence or absence of accessories and other components connected to an external electrical device or connector. A low-cost detection circuit reliably distinguishes between a compromised connector and the presence of an actual device, thereby, preventing false detection scenarios. In various embodiments, the detection circuit accomplishes this by using a zero-crossing detector and/or a digital signal, which serves as a measure of impedance, to detect, within an identification period, the presence of the external device.