Power supply system
To prevent an overvoltage from being applied to a load in a power reception circuit of a power supply system. A power supply system is provided which includes a power supply device equipped with a power supply coil, and a power reception device equipped with a power reception coil. When a resonance circuit is in a resonance state, a peak voltage value of a voltage generated in the power reception coil is set higher than a prescribed voltage value. When the resonance circuit is in a non-resonance state, the peak voltage value of the voltage generated in the power reception coil is set lower than the prescribed voltage value.
1. A power supply system comprising:
a power supply device and a power reception device, the power supply system supplying power from the power supply device to the power reception device,
wherein the power supply device includes a power supply coil, and
wherein the power reception device includes:
a resonance circuit having a power reception coil fed with the power from the power supply coil;
a resonance capacitor that resonates with the power reception coil;
a switching element that changes an electrical connection state of the resonance capacitor to control a resonance state of the resonance circuit; and
a rectifying circuit that rectifies and smooths an AC output voltage generated in the resonance circuit to obtain DC power, and a load supplied with the DC power obtained from the rectifying circuit,
wherein the switching element is controlled by a resonance control circuit including a reference power supply and a comparator connected to the switching element, the comparator controlling the switching element depending upon a divided voltage from the resonance circuit and a reference voltage from the reference power supply,
such that when the resonance circuit is in the resonance state, the switching element is in an ON state and a peak voltage value of a voltage generated in the power reception coil is set higher than a prescribed voltage value, and
wherein when the resonance circuit is in a non-resonance state, the switching element is in an OFF state and the peak voltage value of the voltage generated in the power reception coil is set lower than the prescribed voltage value.
2. The power supply system according to claim 1 , wherein when the resonance circuit is in the non-resonance state, a peak portion of the voltage generated in the power reception coil is driven to be a voltage waveform having a flat portion.