Wireless power transmitter tuning
First Claim
1. An apparatus configured to wirelessly provide power to one or more chargeable devices, the apparatus comprising:
- a transmit circuit comprising a transmit coil, the transmit circuit being configured to wirelessly provide power to a first chargeable device, the transmit circuit being further configured to resonate at a resonant frequency, the transmit circuit having a reactance, wherein the transmit circuit comprises a reactive element;
a driver circuit configured to drive the transmit circuit;
a detection circuit configured todetermine a baseline current level through the driver circuit,detect a first change in current through the driver circuit indicating a first change in the resonant frequency in response to transmitting power to the first chargeable device, anddetect a second change in current through the driver circuit indicating a second change in the resonant frequency in response to transmitting power to a second chargeable device while providing power to the first chargeable device; and
a tuning circuit configured tocycle the reactance of the transmit circuit through a first plurality of reactance values in response to the first change in the resonant frequency while providing power to the first chargeable device,determine a respective first plurality of current values by measuring current through the driver circuit at the first plurality of reactance values,select one of the first plurality of reactance values based on the baseline current level and the determined first plurality of current values in response to the first change in the resonant frequency and adjust the reactance of the transmit circuit to the selected reactance value of the first plurality of reactance values,cycle the reactance of the transmit circuit through a second plurality of reactance values in response to the second change in the resonant frequency while providing power to the first and the second chargeable devices,determine a respective second plurality of current values by measuring current through the driver circuit at the second plurality of reactance values,select one of the second plurality of reactance values based on the baseline current level and the determined second plurality of current values in response to the second change in the resonant frequency and adjust the reactance of the transmit circuit to the selected reactance value of the second plurality of reactance values.
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Accused Products
Abstract
This disclosure provides systems, methods and apparatus for tuning a wireless power transmitter. In one aspect an apparatus configured to wirelessly provide power to a load is provided. The apparatus includes a transmit circuit including a transmit coil. The transmit circuit is configured to wirelessly provide power to the load. The transmit coil is configured to resonate at a resonant frequency. The transmit circuit has a reactance. The apparatus further includes a detection circuit configured to detect a change in the resonant frequency while providing power to the load. The apparatus further includes a tuning circuit configured to adjust the reactance based on the change.
24 Citations
34 Claims
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1. An apparatus configured to wirelessly provide power to one or more chargeable devices, the apparatus comprising:
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a transmit circuit comprising a transmit coil, the transmit circuit being configured to wirelessly provide power to a first chargeable device, the transmit circuit being further configured to resonate at a resonant frequency, the transmit circuit having a reactance, wherein the transmit circuit comprises a reactive element; a driver circuit configured to drive the transmit circuit; a detection circuit configured to determine a baseline current level through the driver circuit, detect a first change in current through the driver circuit indicating a first change in the resonant frequency in response to transmitting power to the first chargeable device, and detect a second change in current through the driver circuit indicating a second change in the resonant frequency in response to transmitting power to a second chargeable device while providing power to the first chargeable device; and a tuning circuit configured to cycle the reactance of the transmit circuit through a first plurality of reactance values in response to the first change in the resonant frequency while providing power to the first chargeable device, determine a respective first plurality of current values by measuring current through the driver circuit at the first plurality of reactance values, select one of the first plurality of reactance values based on the baseline current level and the determined first plurality of current values in response to the first change in the resonant frequency and adjust the reactance of the transmit circuit to the selected reactance value of the first plurality of reactance values, cycle the reactance of the transmit circuit through a second plurality of reactance values in response to the second change in the resonant frequency while providing power to the first and the second chargeable devices, determine a respective second plurality of current values by measuring current through the driver circuit at the second plurality of reactance values, select one of the second plurality of reactance values based on the baseline current level and the determined second plurality of current values in response to the second change in the resonant frequency and adjust the reactance of the transmit circuit to the selected reactance value of the second plurality of reactance values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of tuning a wireless power transmitter for providing power to one or more chargeable devices, the method comprising:
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determining a baseline current level through a driver circuit of the wireless power transmitter; detecting a first change in current through the driver circuit indicating a first change in a resonant frequency of a transmit circuit comprising a transmit coil of the wireless power transmitter in response to transmitting power to a first chargeable device; adjusting a tuning reactance of the transmit circuit in response to the detection of the first change in the resonant frequency while wirelessly providing power to the first chargeable device, wherein adjusting the tuning reactance in response to the detection of the first change in the resonant frequency comprises cycling a reactance of the transmit circuit through a first plurality of reactance values, determining a respective first plurality of current values by measuring the current through the driver circuit at the first plurality of reactance values, selecting one of the first plurality of reactance values based on the baseline current level and the determined first plurality of current values, and adjusting the reactance of the transmit circuit to the selected reactance value of the first plurality of reactance values; detecting a second change in current through the driver circuit indicating a second change in the resonant frequency in response to transmitting power to a second chargeable device while providing power to the first chargeable device; and adjusting the tuning reactance of the transmit circuit in response to the detection of the second change in the resonant frequency while wirelessly providing power to the first chargeable device and the second chargeable device, wherein adjusting the tuning reactance in response to the detection of the second change in the resonant frequency comprises cycling the reactance of the transmit circuit through a second plurality of reactance values, determining a respective second plurality of current values by measuring the current through the driver circuit at the second plurality of reactance values, selecting one of the second plurality of reactance values based on the baseline current level and the determined second plurality of current values, and adjusting the reactance of the transmit circuit to the selected reactance value of the second plurality of reactance values. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus configured to wirelessly provide power to one or more chargeable devices, the apparatus comprising:
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means for wirelessly transmitting power to a first chargeable device and a second chargeable device, the means for wirelessly transmitting power being configured to resonate at a resonant frequency, the means for wirelessly transmitting power having a reactance; means for driving the means for wirelessly transmitting power; means for determining a baseline current level through the means for driving; means for detecting a first change in current through the means for driving indicating a first change in the resonant frequency in response to transmitting power to the first chargeable device; means for detecting a second change in current through the means for driving indicating a second change in the resonant frequency in response to transmitting power to a second chargeable device while providing power to the first chargeable device; and means for tuning configured to cycle the reactance of the means for wirelessly transmitting power through a first plurality of reactance values in response to the first change in the resonant frequency while wirelessly providing power to the first chargeable device, determine a respective first plurality of current values by measuring current through the means for driving at the first plurality of reactance values, select one of the first plurality of reactance values based on the baseline current level and the determined first plurality of current values and adjust the reactance of the means for wirelessly transmitting power to the selected reactance value of the first plurality of reactance values, cycle the reactance of the means for wirelessly transmitting power through a second plurality of reactance values in response to the second change in the resonant frequency while wirelessly providing power to the first chargeable device and the second chargeable device, determine a respective second plurality of current values by measuring current through the means for driving at the second plurality of reactance values, select one of the second plurality of reactance values based on the baseline current level and the determined second plurality of current values and adjust the reactance of the means for wirelessly transmitting power to the selected reactance value of the second plurality of reactance values. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification