Patent attributes
A wireless power system has a wireless power transmitting device such as a charging puck and a wireless power receiving device such as a wristwatch. The charging puck may have a three-wire cable that is coupled between a connector and a puck housing. The wireless power transmitting device may have a set of four coils or other number of wireless power transmitting coils in the puck housing. A switch may be coupled in series with each of the four coils. Control circuitry in the wireless power transmitting device may activate a subset of the switches to switch a subset of the coils into use in transmitting the wireless power to the wireless power receiving device. The control circuitry may have a main portion in the connector that uses a tone-based encoding scheme or other encoding scheme to transmit switch configuration commands to a secondary portion in the puck housing.