Wireless power transmitter
AssigneeRohm Co., Ltd.
InventorMasatoshi WATANABE
Life of this patent
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Abstract
A transmission antenna includes a resonant capacitor and a transmitter coil coupled in series. The driver includes a bridge circuit structured to apply a driving voltage to the transmission antenna. A current sensor detects current IS flowing through the bridge circuit. A foreign object detector detects the current IS flowing through the bridge circuit while changing switching frequency of the bridge circuit and determines whether a foreign matter is present or absent based on a difference between two frequencies fH and fL giving current lower than a peak by a predetermined ratio.
Claims14
A wireless power transmitter structured to transmit a power signal to a wireless power receiver, comprising:
- a transmission antenna including a resonant capacitor and a transmitter coil coupled in series;
- a driver including a bridge circuit structured to apply a driving voltage to the transmission antenna;
- a current sensor structured to detect a current flowing through the bridge circuit;
- and
- a foreign object detector structured to detect the current flowing through the bridge circuit while changing switching frequency of the bridge circuit and determine whether a foreign object is present or absent based on a difference between two frequencies fH and fL giving current lower than a peak by a predetermined ratio.
A wireless charger comprising:
- a transmission antenna including a resonant capacitor and a transmitter coil coupled in series;
- a driver including a bridge circuit structured to apply a driving voltage to the transmission antenna;
- a current sensor structured to detect a current flowing through the bridge circuit;
- and
- a foreign object detector structured to detect the current flowing through the bridge circuit while changing switching frequency of the bridge circuit and determine whether a foreign object is present or absent based on a difference between two frequencies fH and fL giving current lower than a peak by a predetermined ratio.
A foreign object detection method in a wireless power receiver including
- a transmission antenna including a resonant capacitor and a transmitter coil coupled in series, and
- a bridge circuit structured to apply a driving voltage to the transmission antenna, the foreign object detection method comprising:
- detecting a current flowing through the bridge circuit while changing switching frequency of the bridge circuit;
- and
- determining whether a foreign object is present or absent based on a difference between two frequencies fH and fL giving current lower than a peak by a predetermined ratio.
Dependencies are inferred from the claim text.