High efficiency wireless charging

A system of a power device and a portable device for wireless charging of a battery of the portable device,

• wherein the power device comprises a power transmitter stage and a power receiver stage connected with a power antenna, the portable device comprises a portable transmitter stage and a portable receiver stage connected to a portable antenna;
• wherein the power transmitter stage is built to generate a magnetic field in the RFID frequency range and to modulate it with transmitter data and to transmit the modulated magnetic field with the power antenna;
• wherein the portable receiver stage is built to receive an antenna signal from the receiver antenna exposed to the modulated magnetic field and to demodulate the transmitter data and to rectify the antenna signal to charge the battery in charging cycles;
• wherein the portable transmitter stage is built to use an amplitude modulation to modulate the magnetic field with portable transmitter data;
• wherein the power receiver stage is built to demodulate the portable transmitter data;
• wherein the portable transmitter stage is built to transmit power adjustment data to increase or to decrease the power transmitted with the magnetic field emitted with the power antenna of the power transmitter stage and needed to charge the battery;
• wherein the power receiver stage is built to receive the power adjustment data and to steer the power transmitter stage to transmit more or less power in the generated magnetic field;
• and
• wherein the power device and the portable device are built to activate a charge mode and wherein the power transmitter stage in activated charge mode is built to add the functionality to use a frequency modulation to modulate the magnetic field to transmit the transmitter data and wherein the portable receiver stage in activated charge mode is built to process a frequency demodulation of the antenna signals to receive the transmitter data.