Class E amplifier overload detection and prevention
First Claim
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1. A wireless power transfer apparatus, comprising:
- an amplifier circuit operably coupled to a coil configured to wirelessly transfer power to a receiver, the amplifier circuit comprising a switching element; and
a monitoring circuit configured to;
cause the switching element to be in an open position during a first phase,cause the switching element to be in a closed position during a second phase in response to determining that a value indicative of a voltage across the switching element falls below a threshold value, andcause the switching element to be in a closed position during a third phase.
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Abstract
Systems, methods and apparatus are disclosed for amplifiers for wireless power transfer. In one aspect a method is provided for controlling operation of an amplifier, such as a class E amplifier. The method may include monitoring an output of the amplifier. The method may further include adjusting a timing of an enabling switch of the amplifier based on the output of the amplifier.
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Citations
18 Claims
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1. A wireless power transfer apparatus, comprising:
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an amplifier circuit operably coupled to a coil configured to wirelessly transfer power to a receiver, the amplifier circuit comprising a switching element; and a monitoring circuit configured to; cause the switching element to be in an open position during a first phase, cause the switching element to be in a closed position during a second phase in response to determining that a value indicative of a voltage across the switching element falls below a threshold value, and cause the switching element to be in a closed position during a third phase. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of wireless charging, comprising:
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opening a switching element of an amplifier circuit coupled to a coil during a first phase, the coil configured to wirelessly transfer power to a receiver; closing the switching element during a second phase in response to determining that a voltage across the switching element falls below a threshold value; and closing the switching element during a third phase. - View Dependent Claims (12, 13)
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14. A wireless power transfer apparatus, comprising:
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a coil configured to wirelessly transfer power via a wireless field; a driver circuit operably coupled to the coil, the driver circuit configured to receive an input waveform signal, the driver circuit comprising a class E amplifier circuit comprising a switching element controlled by the input waveform signal; and a controller configured to adjust a timing of the input waveform signal based on monitoring characteristics of the driver circuit, the characteristics indicative of reactive variations of a load presented to the driver circuit caused by variations in coupling via the wireless field, the input waveform signal is configured to; adjust a state of the switching element to cause current to not be conducted through the switching element during a first phase; and adjust the state of the switching element to cause current to be conducted through the switching element during a second phase after the first phase, and wherein the controller is configured to; adjust the timing of the input waveform to cause current to be conducted through the switching element during a third phase between the first and second phase in response to determining that a value indicative of a voltage across the switching element falls below a threshold value. - View Dependent Claims (15, 16, 17, 18)
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Specification