Intelligent pillow type wireless charger for fully implantable middle ear hearing device with a function of electromagnetic emission reduction

Recently, implantable middle ear hearing devices have been developed as full implant by several countries for hearing impaired people. These devices will be surgically implanted in human temporal bone, a rechargeable battery is employed for long-term implant. To charge the battery, a pillow type wireless charger using electromagnetic coupling has been developed in South Korea. In the previous device, several primary coils are used, which can surround head considering head's movement in sleep. However, this device should unnecessarily consume power to drive the uncoupled primary coil. Especially, users must expose themselves to electromagnetic field generated from all primary coils during the charge process. In order to solve these problems, an intelligent pillow type wireless charger, which can recognize the implanted coil's position using hall effect sensors and which can drive the only primary coil among primary coil's array, has been proposed to reduce potential risks from the electromagnetic field emission.