To solve such a problem that in radio power transmission by a magnetic resonance method, the absence of impedance control of a transceiver leads to low efficiency, but incorporating an impedance control function into a small-sized device, such as portable device, results in a large circuit scale and size, thus bringing a negative effect on miniaturization.
When a small-sized device serving as a receiver cannot mount an impedance control function, a transmitter determines the presence/absence of the impedance function and carries out impedance control by switching an impedance control method. As a result, radio power transmission can be carried out efficiently even if the receiver cannot mount the impedance control function. Hence radio power transmission performance is improved.
Daisuke Nagano
Kentaro Fujii