Systems and methods for maintaining a drive signal to a resonant circuit at a resonant frequency
First Claim
1. A system for maintaining a drive signal to a resonant circuit at a resonant frequency comprising:
- an oscillator configured to provide an output to a phase comparator and a drive circuit, the drive circuit configured to provide a drive signal to a resonant circuit;
a phase detector configured to receive a filtered version of the drive signal by sensing a voltage at a junction of an inductor and a capacitor of the resonant circuit and provide a phase-indicating signal to the phase comparator; and
the phase comparator, wherein the phase comparator is configured to provide a signal based on a phase difference between the oscillator output and the phase-indicating signal, wherein the signal from the phase comparator is used to control the frequency of the oscillator such that the phase difference converges to a fixed value.
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Accused Products
Abstract
Systems and methods for maintaining a drive signal to a resonant circuit at a resonant frequency are provided. A system for maintaining a drive signal to a resonant circuit at a resonant frequency can include: an oscillator configured to provide an output to a phase comparator and a drive circuit, the drive circuit configured to provide a drive signal to a resonant circuit; a phase detector configured to receive a filtered version of the drive signal from the resonant circuit and provide a phase-indicating signal to the phase comparator; and the phase comparator, wherein the phase comparator is configured to provide a signal based on the phase difference between the oscillator output and the phase-indicating signal, wherein the signal from the phase comparator is used to control the frequency of the oscillator such that the phase difference converges to a fixed value.
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Citations
36 Claims
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1. A system for maintaining a drive signal to a resonant circuit at a resonant frequency comprising:
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an oscillator configured to provide an output to a phase comparator and a drive circuit, the drive circuit configured to provide a drive signal to a resonant circuit; a phase detector configured to receive a filtered version of the drive signal by sensing a voltage at a junction of an inductor and a capacitor of the resonant circuit and provide a phase-indicating signal to the phase comparator; and the phase comparator, wherein the phase comparator is configured to provide a signal based on a phase difference between the oscillator output and the phase-indicating signal, wherein the signal from the phase comparator is used to control the frequency of the oscillator such that the phase difference converges to a fixed value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for maintaining a drive signal to a resonant circuit at a resonant frequency comprising:
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an oscillator configured to provide an output to a phase comparator, a drive circuit having variable gain, and a low-pass filter, the drive circuit configured to provide a drive signal to a resonant circuit, the low-pass filter having a characteristic frequency that is substantially the same as the resonant frequency of the resonant circuit; a phase detector configured to receive a filtered signal from each of the low-pass filter and the resonant circuit, and responsively provide a phase-indicating signal to the phase comparator representing the phase of whichever of the phase detector inputs is stronger; and the phase comparator, wherein the phase comparator is configured to provide a signal based on a phase difference between the oscillator output and the phase-indicating signal, wherein the signal from the phase comparator is used to control the frequency of the oscillator. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 36)
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18. A method for maintaining a drive signal to a resonant circuit at a resonant frequency comprising:
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using an oscillator to provide an output to a phase comparator and a drive circuit, the drive circuit configured to provide a drive signal to a resonant circuit; using a phase detector to receive a filtered version of the drive signal by sensing a voltage at a junction of an inductor and a capacitor of the resonant circuit and provide a phase-indicating signal to the phase comparator; using the phase comparator to provide a signal based on a phase difference between the oscillator output and the phase-indicating signal; and using the signal from the phase comparator to control the frequency of the oscillator such that the phase difference converges to a fixed value. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for maintaining a drive signal to a resonant circuit at a resonant frequency comprising:
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using an oscillator to provide an output to a phase comparator, a drive circuit having variable gain, and a low-pass filter, the drive circuit configured to provide a drive signal to a resonant circuit, the low-pass filter having a characteristic frequency that is substantially the same as the resonant frequency of the resonant circuit; using a phase detector to receive a filtered signal from each of the low-pass filter and the resonant circuit, and responsively provide a phase-indicating signal to the phase comparator representing the phase of whichever of the phase detector inputs is stronger; using the phase comparator to provide a signal based on a phase difference between the oscillator output and the phase-indicating signal; and using the signal from the phase comparator to control the frequency of the oscillator. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35)
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Specification