Patent ID: 9030051
Filing Date: 2015-05-12
Classification: H02J,H04B

Abstract:
1. An electronic device comprising: a power pick-up unit that receives electrical power wirelessly via an electromagnetic field generated by a power transmitter; a modulator that causes the electromagnetic field to change between first and second states by one of amplitude modulation, frequency modulation or phase modulation, in a first manner that can be detected by the power transmitter as logic bits in a communication bit stream for sending data to the power transmitter during communication time periods, the modulator causes the electromagnetic field to change between the first and second states in a second manner that is not detected by the power transmitter as the logic bits during pause time periods when data is not being sent to the power transmitter, wherein: the power pick-up unit comprises a rectifier; the rectifier converts an AC current, generated by the electromagnetic field, into a DC current with a voltage that ripples around a rectified voltage level; during the communication time periods, the modulator causes the rectified voltage level to change between first and second voltage levels representative of the logic bits; and during the pause time periods, the modulator causes the rectified voltage level to change within a range between the first and second voltage levels with a duty cycle selected to minimize a difference between an average level of the voltage output by the rectifier during the pause time periods and an average level of the voltage output by the rectifier during the communication time periods.