Patent attributes
In a non-contact power supply system, an electric power receiving device with suppressed heat generation is provided. The electric power receiving device is configured with a resonance circuit which includes a resonance capacity and a resonance coil acting as a receiving antenna, and receives electric power in a non-contact manner using resonant coupling of the resonance circuit. When receiving electric power, the electric power receiving device monitors the reception electric power received by the resonance circuit and controls the resonance frequency of the resonance circuit so as to keep the reception electric power from exceeding a target electric power level (PTGT). Accordingly, even when an electric power larger than the electric power required by the electric power receiving device is transmitted from the transmitting side, the electric power receiving device operates not to receive the electric power greater than the target electric power level.