Patent ID: 6118250
Filing Date: 2000-09-12
Classification: H02J

Abstract:
A method of charging an internal and external battery in a power supply assembly of a portable phone, wherein the phone has a battery-charging control unit for charging the phone batteries using a plurality of battery-charging rates, comprising the steps of:a) comparing the voltage of the internal battery to a pre-determined cut-off voltage;b) applying a trickle-charge to the internal battery if the voltage of the internal battery compared in step (a) is less than the cut-off voltage, wherein the trickle-charge is applied until the voltage of the internal battery exceeds the cut-off voltage;c) applying a fast-charge to the internal battery until the internal battery voltage exceeds a pre-determined voltage threshold;d) comparing the voltage of the external battery to the pre-determined cut-off voltage;e) applying a trickle-charge to the external battery if the voltage of the external battery compared in step (d) is less than the cut-off voltage, wherein the trickle-charge is applied until the voltage of the external battery exceeds the cut-off voltage;f) applying a fast-charge to the external battery until the external battery voltage exceeds the pre-determined voltage threshold;g) applying a top-off charge to the internal battery until the internal battery is fully charged; andh) applying a top-off charge to the external battery until the external battery is fully charged.