Patent ID: 7940026

Claim:
A power manager unit for managing power delivered to a battery powered device, comprising: a main bus; an inrush current limiter, wherein the inrush current limiter limits current from a power line connected to the inrush current limiter; a voltage converter unit connected to the main bus and to the output of the inrush current limiter; a voltage sensor unit coupled to the main bus and arranged to sense a voltage on the main bus; and a switchover circuit arranged to, upon connection of a power line to the inrush current limiter-causing the voltage sensor unit to sense a voltage on the main bus above a predefined threshold, connect the voltage converter unit to the battery powered device, and upon detection that the battery is in a fully charged state, disconnect the battery from the voltage converter unit such that no current flows to or from the battery, wherein the switchover circuit is further arranged to, upon disconnection of a power line from the voltage converter causing the voltage sensor unit to sense a voltage on the main bus below the predefined threshold, disconnect the voltage converter unit from the battery powered device and connect a battery to the battery powered device.