Power receiver control circuit for wireless power receiver apparatus

A control circuit that controls a wireless power receiver apparatus, wherein the wireless power receiver apparatus comprises:

• a reception coil;
• a rectifier circuit that rectifies a current that flows through the reception coil;
• and
• a smoothing capacitor connected to an output of the rectifier circuit,
• wherein the control circuit comprises:
• a target voltage range setting unit that sets an upper limit voltage and a lower limit voltage that define a target voltage range to be set for a rectified voltage that develops across the smoothing capacitor;
• an electric power control unit that generates a power control signal for controlling transmission power from the wireless power transmitter apparatus, based on a comparison result obtained by comparing the rectified voltage with each of the upper limit voltage and the lower limit voltage;
• and
• a modulator that generates a modulated signal by using the power control signal, and that transmits the modulated signal to the wireless power transmitter apparatus via the reception coil,
• wherein the power control signal is switchable between a first state indicative of maintaining the transmission power, a second state indicative of increasing the transmission power, and a third state indicative of decreasing the transmission power,
• and wherein, when the rectified voltage becomes lower than the lower limit voltage as a result of the power control signal being set to the third state, the target voltage range setting unit changes the target voltage range.

A control method for a wireless power receiver apparatus, wherein the wireless power receiver apparatus comprises:

• a reception coil;
• a rectifier circuit that rectifies a current that flows through the reception coil;
• and
• a smoothing capacitor connected to an output of the rectifier circuit,
• wherein the control method comprises:
• setting an upper limit voltage and a lower limit voltage that define a target voltage range to be set for a rectified voltage that develops across the smoothing capacitor;
• comparing the rectified voltage with each of the upper limit voltage and the lower limit voltage, and generating a power control signal for controlling transmission power from the wireless power transmitter apparatus, based on a comparison result thus obtained;
• and
• generating a modulated signal by using the power control signal, and transmitting the modulated signal to the wireless power transmitter apparatus via the reception coil,
• wherein the power control signal is switchable between a first state indicative of maintaining the transmission power, a second state indicative of increasing the transmission power, and a third state indicative of decreasing the transmission power,
• and wherein, in the setting of the upper limit voltage and the lower limit voltage, when the rectified voltage becomes lower than the lower limit voltage as a result of the power control signal being set to the third state, the target voltage range is changed.

A control method for a wireless power receiver apparatus, wherein the wireless power receiver apparatus comprises:

• a reception coil;
• a rectifier circuit that rectifies a current that flows through the reception coil;
• and
• a smoothing capacitor connected to an output of the rectifier circuit,
• wherein the control method comprises:
• setting an upper limit voltage and a lower limit voltage that define a target voltage range to be set for a rectified voltage that develops across the smoothing capacitor;
• comparing the rectified voltage with each of the upper limit voltage and the lower limit voltage, and generating a power control signal for controlling transmission power from the wireless power transmitter apparatus, based on a comparison result thus obtained;
• and
• modulating the power control signal, and transmitting the power control signal thus modulated to the wireless power transmitter apparatus via the reception coil,
• and wherein, in the setting of the upper limit voltage and the lower limit voltage, upon detection of an oscillation state in the rectified voltage, the target voltage range is changed.