Patent ID: 7595607
Filing Date: 2009-09-29
Classification: G01R,H02J

Abstract:
1. A method for determining whether a battery is electrically and physically connected to a battery charger, said method comprising: providing an electric device that includes a battery and a superimposed signal detector circuit; connecting a battery charger to the electric device across at least one connector; monitoring, using the superimposed signal detector circuit, a battery charging voltage supplied to the electric device across the at least one connector by the battery charger, wherein the battery charger has superimposed a known signal on the battery charging voltage using a shunt to reduce the battery charging voltage for a predetermined interval of time; determining that the battery charger is connected when the known superimposed signal is present and that the battery charger is not connected when the known superimposed signal is absent; and opening a switch upon detection of the known superimposed signal to enable executing an output.