System and method of providing communications in a wireless power transfer system

A system for transferring power to a remote device from an inductive power supply and for communicating data from the remote device to the inductive power supply, said system comprising:

• a power receiver adapted to receive a variable frequency power transmission signal;
• a controller adapted to encode a data stream of bits into a fixed frequency communication signal;
• a communication transmitter adapted to selectively toggle a load for modulating the fixed frequency communication signal on the variable frequency power transmission signal, wherein each bit of the data stream is represented by a plurality of modulations on the variable frequency power transmission signal;
• and
• a detector configured to decode the data stream from the variable frequency power transmission signal by timeslicing the variable frequency power transmission signal and comparing a DC offset between two time slices.

A system for transferring power to a remote device from an inductive power supply and for communicating data between the remote device and the inductive power supply using keyed modulation, said system comprising:

• a power receiver adapted to receive a variable frequency power transmission signal;
• a controller for encoding a data stream of bits in to a fixed frequency communication signal;
• a communication transmitter selectively toggling a load for modulating the fixed frequency communication signal on the variable frequency power transmission signal, wherein each bit of the data stream is represented by a plurality of modulations on the variable frequency power transmission signal;
• and
• an inductive power supply controller configured to decode the data stream from the variable frequency power transmission signal by timeslicing the variable frequency power transmission signal and comparing a DC offset between two time slices.

An inductive power supply for transferring inductive power to a remote device and for receiving data via backscatter modulation from the remote device, said inductive power supply comprising:

• a power transmitter for transmitting a variable frequency power transmission signal;
• a wireless communication receiver configured to detect modulation on the variable frequency power transmission signal, wherein the inductive power supply decodes a data stream from the variable frequency power transmission signal, and wherein each bit of the data stream is represented by a plurality of modulations on the variable frequency power transmission signal;
• and
• wherein the inductive power supply decodes the data stream by timeslicing the variable frequency power transmission signal and comparing a DC offset between two time slices.