Magnetic resonance wireless power transmission device capable of adjusting resonance frequency

A wireless power transmitting unit, comprising:

• a power amplifier configured to amplify a power signal using a driving frequency signal;
• a resonator constituting a resonant tank, and configured to wirelessly transmit the amplified power signal through magnetic resonance using a resonant frequency of the resonant tank;
• and
• a resonance controller configured to tune the resonant frequency of the resonator by controlling a duty ratio with a frequency signal generated by the resonator,
• wherein the resonance controller is configured to control a duty ratio of a switch of the resonator by changing a tuning voltage that is applied to a gate of the switch, and
• wherein the resonance controller is configured to control the duty ratio of the switch using the changed tuning voltage and an inductor voltage varying in a sinusoidal waveform at a source of the switch.