Inductive power supply with duty cycle control
First Claim
1. An inductive power supply for providing power wirelessly to a remote device, said inductive power supply comprising:
- a primary circuit for controlling power transfer to the remote device according to at least one operating parameter, said primary circuit configured to adjust a duty cycle of a signal to allow variation in an amount of power transferred to the remote device;
a wireless receiver configured to receive information communicated from the remote device;
a sensor configured to sense a characteristic of power in the inductive power supply;
a tank circuit in electrical communication with said primary circuit, said tank circuit configured to inductively couple with the remote device;
wherein said primary circuit controls, based on sensor output from said sensor, said at least one operating parameter to achieve a desired operating point; and
wherein said primary circuit controls said duty cycle of said signal to maintain an amount of power transferred despite variations in operating conditions that affect resonant frequency.
1 Assignment
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Accused Products
Abstract
An inductive power supply that maintains resonance and adjusts duty cycle based on feedback from a secondary circuit. A controller, driver circuit and switching circuit cooperate to generate an AC signal at a selected operating frequency and duty cycle. The AC signal is applied to the tank circuit to create an inductive field for powering the secondary. The secondary communicates feedback about the received power back to the primary controller. The power transfer efficiency may be optimized by maintaining the operating frequency substantially at resonance, and the amount of power transferred may be controlled by adjusting the duty cycle.
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Citations
20 Claims
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1. An inductive power supply for providing power wirelessly to a remote device, said inductive power supply comprising:
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a primary circuit for controlling power transfer to the remote device according to at least one operating parameter, said primary circuit configured to adjust a duty cycle of a signal to allow variation in an amount of power transferred to the remote device; a wireless receiver configured to receive information communicated from the remote device; a sensor configured to sense a characteristic of power in the inductive power supply; a tank circuit in electrical communication with said primary circuit, said tank circuit configured to inductively couple with the remote device; wherein said primary circuit controls, based on sensor output from said sensor, said at least one operating parameter to achieve a desired operating point; and wherein said primary circuit controls said duty cycle of said signal to maintain an amount of power transferred despite variations in operating conditions that affect resonant frequency. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An inductive power supply for providing power wirelessly to a remote device, said inductive power supply comprising:
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a primary circuit for controlling power transfer according to at least one operating parameter, said primary circuit configured to adjust a duty cycle of a signal to affect an amount of power transferred; a wireless receiver configured to receive information via a communication link from the remote device; a tank circuit in electrical communication with said primary circuit, said tank circuit configured to inductively couple with the remote device, wherein said primary circuit applies said signal to said tank circuit to transfer power to the remote device; a sensor in electrical communication with said tank circuit, said sensor configured to sense a characteristic of power in said tank circuit; wherein said primary circuit controls said at least one operating parameter to achieve an operating point; and wherein, based on a sensor output from said sensor, said primary circuit adjusts said duty cycle of said signal to change said amount of power transferred. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15)
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16. A method for wirelessly supplying power from an inductive power supply to a remote device, comprising the steps of:
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placing a remote device in sufficient proximity to an inductive power supply to establish an inductive coupling between the remote device and a tank circuit of the inductive power supply; in the inductive power supply, operating the inductive power supply according to a frequency parameter to transfer power from tank circuit to the remote device via the inductive coupling; in the inductive power supply, controlling a duty cycle of a signal supplied to the tank circuit to transfer power from the tank circuit to the remote device via the inductive coupling; sensing a characteristic of power in the tank circuit, wherein the characteristic of power is indicative of a reflected impedance of the remote device through the inductive coupling; receiving, in the inductive power supply, information communicated from the remote device; and determining, based at the sensed characteristic of power, whether to adjust the frequency parameter or the duty cycle, wherein adjusting at least one of the frequency parameter and the duty cycle changes an amount of power transferred to the remote device. - View Dependent Claims (17, 18, 19, 20)
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Specification