Apparatus and method for continuous variable reactive impedance control
First Claim
1. A circuit with an adjustable reactive impedance, the circuit having an oscillation frequency, the circuit comprising:
- an oscillating circuit;
a reactive component;
a switch coupled to said reactive component, said switch and said reactive component being coupled to said oscillating circuit; and
a controller operatively coupled to said switch for controlling the opening and closing of said switch, said controller having a first component for determining a duration, said duration being a portion of a quarter cycle of the oscillation frequency, a second component for identifying the start and the end of a half-cycle of the oscillation frequency, and a third component for closing said switch for said duration beginning at the start of each half-cycle and opening said switch after said duration.
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Abstract
An apparatus and method for continuous variable reactive impedance control. The apparatus and method enable the continuous variation of the reactive impedance of an oscillating circuit. A reactive component, in one embodiment a capacitor, is switched into the oscillating circuit for a duration at the beginning and end of each half cycle of the oscillation frequency. Through varying the duration, the oscillation frequency is varied between the frequency that occurs without the reactive component in the circuit and the frequency with the reactive component permanently in the circuit. A controller determines the duration and controls a switch coupled to the reactive component. The apparatus and method may be used to adjust the oscillation frequency of a resonant circuit or to match the resonant frequency to a driving frequency in a driven oscillating circuit so as to improve efficiency.
18 Citations
29 Claims
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1. A circuit with an adjustable reactive impedance, the circuit having an oscillation frequency, the circuit comprising:
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an oscillating circuit;
a reactive component;
a switch coupled to said reactive component, said switch and said reactive component being coupled to said oscillating circuit; and
a controller operatively coupled to said switch for controlling the opening and closing of said switch, said controller having a first component for determining a duration, said duration being a portion of a quarter cycle of the oscillation frequency, a second component for identifying the start and the end of a half-cycle of the oscillation frequency, and a third component for closing said switch for said duration beginning at the start of each half-cycle and opening said switch after said duration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of adjusting the reactive impedance of a circuit, the circuit having an oscillation frequency and including an oscillating circuit and a reactive component that is selectively coupled to the oscillating circuit, the method comprising the steps of:
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identifying the start and end of a half-cycle of the oscillation frequency;
determining a duration, said duration being a portion of a quarter-cycle of the oscillation frequency;
coupling the reactive component to the oscillating circuit for said duration beginning at the start of each half-cycle;
decoupling the reactive component from the oscillating circuit after said duration; and
re-coupling the reactive component to the oscillating circuit for said duration expiring at the end of each half-cycle. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A magnetic inductive transmitter having an oscillation frequency, comprising:
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an oscillating circuit, including an inductive antenna and a capacitive component;
a secondary capacitor;
a switch coupled to said secondary capacitor, said switch and said secondary capacitor being coupled to said capacitive component of said oscillating circuit; and
a controller operatively coupled to said switch for controlling the opening and closing of said switch, said controller having a first component for determining a duration, said duration being a portion of a quarter cycle of the oscillation frequency, a second component for identifying the start and end of a half-cycle of the oscillation frequency, and a third component for closing said switch for said duration beginning at the start of each half-cycle and opening said switch after said duration.
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Specification