US Patent 7019491 Method and apparatus for indication of a charging condition

The invention concerns an apparatus (100) for indication of a charging condition. The apparatus includes an indication circuit (126) having at least one electromagnet (120) and a charge control circuit (128) for controlling charging current to a portable device (110). The indication circuit causes the apparatus to electromagnetically engage the portable device and the charge control circuit provides charging current to the portable device during the engagement. The indication circuit also causes the apparatus to electromagnetically decouple the portable device when the portable device is charged to a predetermined level to permit a user to remove the portable device from the apparatus.