Methods and systems for measuring power in wireless power systems
First Claim
1. An apparatus for determining a phase difference between a time-varying voltage and a time-varying current, comprising:
- a transmit circuit comprising an antenna, the transmit circuit configured to generate a wireless field via the antenna for transferring charging power to a receiver device, the wireless field based on the time-varying voltage and the time-varying current;
a phase detection circuit configured to output a phase signal indicating a duration of a phase offset between the time-varying voltage and the time-varying current;
a capacitor configured to receive a current from a current source for the duration of the phase offset between the time-varying voltage and the time-varying current; and
at least one switch operably coupled to the capacitor and configured to selectively couple the current from the current source to the capacitor in response to the phase signal, the phase signal allowing activation of the at least one switch.
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Accused Products
Abstract
The invention provides a method and system for precisely measuring AC power and detecting load impedance using a precise analog front-end, zero-crossing detectors, and a phase detection system capable of extracting precise phase information from the sensed voltage and current measurements. More particularly, the invention provides an apparatus, comprising a transmit circuit configured to generate a wireless field via an antenna for transferring charging power to a receiver device, for determining a phase difference between a first signal and a second signal. The apparatus further comprises a phase detection circuit to output a phase signal indicating a duration of a phase offset between a time-varying voltage and a time-varying current of the transmit circuit. The apparatus further comprises a capacitor configured to receive a variable current from a current source for the duration of the phase offset between the time-varying voltage and a time-varying current.
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Citations
20 Claims
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1. An apparatus for determining a phase difference between a time-varying voltage and a time-varying current, comprising:
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a transmit circuit comprising an antenna, the transmit circuit configured to generate a wireless field via the antenna for transferring charging power to a receiver device, the wireless field based on the time-varying voltage and the time-varying current; a phase detection circuit configured to output a phase signal indicating a duration of a phase offset between the time-varying voltage and the time-varying current; a capacitor configured to receive a current from a current source for the duration of the phase offset between the time-varying voltage and the time-varying current; and at least one switch operably coupled to the capacitor and configured to selectively couple the current from the current source to the capacitor in response to the phase signal, the phase signal allowing activation of the at least one switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for determining a phase difference between a first signal and a second signal, comprising:
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generating a phase signal indicating a duration of a phase offset between the first and second signals; selectively coupling a current source to a capacitor in response to the phase signal, the phase signal allowing activation of at least one switch; and receiving a current from the current source for the duration of the phase offset between the first and second signals. - View Dependent Claims (16, 17, 18)
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19. An apparatus for determining a phase difference between a first signal and a second signal, comprising:
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means for generating a phase signal indicating a duration of a phase offset between the first and second signals; means for receiving a current from a current source for the duration of the phase offset between the first and second signals; and at least one means for selectively coupling the current from the current source to the means for receiving a current in response to a phase signal, the phase signal allowing activation of the at least one means for selectively coupling. - View Dependent Claims (20)
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Specification