Power receiving apparatus

A power receiving device (100, 100x) configured to receive alternating power in a wireless manner using a magnetic field, the power receiving device comprising:

• a resonance circuit (110) including a power receiving coil (111) configured to receive the alternating power, the resonance circuit having a magnitude of the alternating power that differs depending on a state of resonance of the resonance circuit or coupling of the power receiving coil;
• a rectifier circuit (120, 120x) that is configured to convert the alternating power into direct-current power;
• a load device (130) that is configured to consume the direct-current power;
• a power control circuit (140, 140x) including a switch (Sw) configured to short-circuit input terminals (P1, P2) of the rectifier circuit, the power control circuit being configured to adjust, between the power receiving coil and the load device, supplied power (Pa) that is a portion of the alternating power to be supplied to the load device;
• a power receiving sensor (160) that is configured to detect reception of the alternating power or the direct-current power;
• and
• a control circuit (150, 150x) configured to control an operation of the power receiving device, wherein
• the control circuit is configured to execute a short-circuit mode and a power supply mode for each half cycle of a cycle (Ca) of the alternating power, the short-circuit mode being a mode in which the input terminals are short-circuited for a predetermined short-circuit mode period, the power supply mode being a mode in which the input terminals are opened for a power supply mode period excluding the short-circuit mode period in the half cycle,
• the control circuit, before start of reception of the alternating power detected by the power receiving sensor, works to set a power supply ratio (D), which is a ratio of the power supply mode period in the half cycle, to be smaller than a minimum target ratio (Dm), the minimum target ratio (Dm) being a minimum value of a target ratio (Dt) that is determined as a function of a state of the coupling capable of setting the supplied power to a predetermined target power (Pt), and
• after detection of the reception of the alternating power by the power receiving sensor, the control circuit works to increase the power supply ratio to the target ratio or less.