Patent ID: 6167289
Filing Date: 2000-12-26
Classification: H02J

Abstract:
A power supply control assembly for a portable phone, comprising:an internal battery for mounting inside a phone housing;an external battery for releasable mounting on the phone housing;a control unit connected to the internal and external batteries to control connection of the batteries to a phone power line; andthe control unit including first and second detectors for detecting the output voltage of the internal and external battery, respectively, first and second switches for controlling connection of the internal battery and external battery, respectively, to the phone power line, and a signal output device connected to the first and second detectors for producing a first output signal and a second output signal dependent on the output of the external battery, the first and second output signals controlling the first and second switches, the first switch being off and the second switch being on when the output voltage of the external battery is above a predetermined minimum value, whereby power is supplied by the external battery, and the first switch being switched on and the second switch being switched off when the output voltage of the external battery falls below said predetermined minimum value, whereby power is supplied by the internal battery;the assembly further including an external voltage input connected to the control unit for supplying a charge input to a selected battery, the control unit further including a detector for detecting when the charge input is connected to a charging device, and a selector for controlling connection of the charge input to the external and internal battery, whereby only one battery is connected to the charge input at any time, and the internal battery is charged prior to the external battery;wherein the charge input has a fast charge input to each battery, and the charge input is connected to first and second trickle charge units having outputs connected to the internal and external battery, respectively, a third switch controlling connection of the first trickle charge unit to the internal battery, and a fourth switch controlling connection of the second trickle charge unit to the external battery, and a controller is connected to the battery outputs and to the fast charge inputs and third and fourth switches to control the speed of charging a selected battery, the controller including means for detecting the output voltage of each battery, initiating a charging cycle when a charge input is detected, connecting a fast charge input to the selected battery if the battery voltage is greater than a predetermined minimum value, and connecting a trickle charge input from the respective trickle charge unit to the selected battery if the battery voltage is below a predetermined minimum value.