A power supply circuit can be configured to generate a supply voltage that provides power to the apparatus. A signal generation circuit can be configured to generate a radio frequency (RF) charging signal. An amplification circuit can be configured to amplify the RF charging signal using the supply voltage and to present the amplified charging signal to a power transmitting coil for transmission of wireless power to a remote device. A communication circuit can be configured to detect amplitude variations in the RF charging signal; detect variations in a voltage level of the supply voltage; adjust the detected amplitude variations in the RF charging signal to compensate for detected variations in a voltage level; and decode data represented by the amplitude variations in the RF charging signal based upon the adjusted amplitude variations.