Patent ID: RE42114

Claim:
A system for controlling the supply of power from an external power source to rechargeable batteries in an apparatus which can be powered either by the external power source or the rechargeable batteries, comprising: a first detector for detecting a difference between a maximum permissible charging current allowed by the rechargeable batteries and a charging current flowing to the rechargeable batteries; a second detector for detecting a maximum useable current by detecting a difference between a maximum suppliable current allowed by the external power source and the current being consumed by the apparatus; a third detector for detecting a difference between the maximum useable current and the charging current flowing to the rechargeable batteries; and a controller for controlling power supplied from the external power source to the rechargeable batteries in accordance with the differences detected by the first and third detectors so that the charging current flowing to the rechargeable batteries does not exceed the maximum permissible charging current and does not exceed the maximum useable current.