Feedback control schemes for wireless power transfer circuits

A wireless power receiving device configured to receive wireless power signals from a wireless power transmitting device, the wireless power receiving device comprising:

• a wireless power transfer coil;
• rectifier circuitry coupled to the wireless power transfer coil and configured to rectify signals from the wireless power transfer coil into a rectifier output voltage;
• and
• control circuitry configured to:
• receive, from the wireless power transmitting device, a status message indicative of an inverter input voltage of the wireless power transmitting device;
• determine, based on the status message received from the wireless power transmitting device, whether the inverter input voltage is at a maximum inverter input voltage level,
• wherein in accordance with determining the inverter input voltage is not at the maximum inverter input voltage level, the control circuitry:
• measures a characteristic of the rectifier circuitry;
• determines a target rectifier output voltage level based on the measured characteristic of the rectifier circuitry;
• and
• dynamically regulates the rectifier output voltage at the target rectifier output voltage level;
• wherein in accordance with determining if the inverter input voltage is at the maximum inverter input voltage level, the control circuitry:
• measures a present rectifier output voltage value;
• compares the present rectifier output voltage value with a minimum fold back voltage level,
• wherein in accordance with determining the present rectifier output voltage value is less than or equal to the minimum fold back voltage level, the control circuitry sets a new target rectifier output voltage level to the minimum fold back voltage level;
• and
• regulates the rectifier output voltage at the new target rectifier output voltage level.

A wireless power receiving device configured to receive wireless power signals from a wireless power transmitting device, the wireless power receiving device comprising:

• a wireless power transfer coil;
• rectifier circuitry coupled to the wireless power transfer coil and configured to rectify signals from the wireless power transfer coil into a rectifier output voltage;
• and
• control circuitry configured to:
• ask the wireless power transmitting device for information indicative of an operating condition of an inverter of the wireless power transmitting device, wherein the wireless power transfer coil is receiving wireless power signals transmitted by the wireless power transmitting device using the inverter;
• wherein the information comprises a status message indicative of whether the inverter of the wireless power transmitting device is operating at a maximum input voltage level;
• wherein in accordance with determining the inverter input voltage is not at the maximum inverter input voltage level, the control circuitry:
• regulates the rectifier output voltage at a target rectifier output voltage level;
• wherein in accordance with determining the inverter input voltage is at the maximum inverter input voltage level, the control circuitry:
• measures a present rectifier output voltage value;
• compares the present rectifier output voltage value with a minimum fold back voltage level,
• wherein in accordance with determining the present rectifier output voltage value is less than or equal to the minimum fold back voltage level, the control circuitry sets a new target rectifier output voltage level to the minimum fold back voltage level;
• and
• regulates the rectifier output voltage at the new target rectifier output voltage level.