20110057606 | SAFETY FEATURE FOR WIRELESS CHARGER - Example embodiments are disclosed for detecting the proximity of a user to a wireless charger and switching off or gradually reducing the power applied to the transmitting coils as long as the user is closer than a threshold distance. In embodiments, a power source circuit in a wireless charging device is configured to produce a source alternating current. A transmitting coil is configured to magnetically couple with a proximately located receiving coil in a user's device, using contact-less electromagnetic induction, to wirelessly provide power to the receiving coil. A power control circuit is coupled between the power source and the transmitting coil, having a control input configured to control power delivered from the power source to the transmitting coil. A proximity detector is positioned near the transmitting coil and coupled to the control input of the power control circuit, to detect proximity of the user to the detector and provide a control signal to the power control circuit to cause the power control circuit to reduce power delivered from the power source to the transmitting coil. In this manner, the exposure of the user is minimized near the active charging surface, to the intense electromagnetic fields required in wireless chargers. | 03-10-2011 |