Patent ID: 6236868
Filing Date: 2001-05-22
Classification: H04B,H04M

Abstract:
An apparatus for sensing the presence of a mobile telephone within a holder for said telephone, comprising:a winding located within one of said telephone, a battery pack of said telephone, and a plug connected to said telephone;a magnetic element disposed within a portion of said holder that is proximate to said winding when said telephone is present within said holder; anddetection circuitry coupled to said winding for detecting, based on current flow through said winding, if said winding is in proximity to said magnetic element which indicates that said telephone is present within said holder;wherein said detection circuitry comprises: a resistive-capacitive (RC) circuit, including a current sense resistor coupled to said winding; and switching circuitry for switchably coupling a source of potential to said RC circuit so as to generate an AC current through said winding, with frequency of said AC current being detected and determinative of whether the telephone is present within the holder.