System and method for measuring variable impedance elements in a wireless sensor
First Claim
1. A wireless remote sensor for sensing a first external parameter and a second external parameter comprising:
- a receiver coil configured to receive power wirelessly from a wireless power transmitter;
an oscillating circuit coupled to said receiver coil whereby oscillations of said oscillating circuit are communicated to the wireless power transmitter by reflected impedance, said oscillating circuit having a first variable impedance element that is configured to vary in response to changes in a value of a sensed first external parameter and a second variable impedance element that is configured to vary in response to changes in a value of a sensed second external parameter, wherein the first and second variable impedance elements are capable of varying independently of power received wirelessly from the wireless power transmitter; and
wherein a duty cycle of said oscillations varies based on variations in said first and second variable impedance elements, whereby said duty cycle of said oscillations is affected by sensed variations in the value of the sensed first and sensed second external parameters.
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Accused Products
Abstract
A wireless remote sensor (110) that is powered by an inductive transmitter (112) and is configured to produce an oscillating wave that varies based on one or more sensed parameters. The oscillating wave is communicated to the inductive transmitter (112) by reflected impedance, where it can be detected to determine the sensed value(s). In another aspect, the present invention provides a wireless remote sensor with a Wheatstone bridge arrangement having an internal resonant circuit to produce an electromagnetic field indicative of the sensed value. In a third aspect, the present invention provides a wireless remote sensor with optical feedback from a reference circuit and a sensor circuit. In a fourth aspect, the present invention provides a wireless remote temperature sensor having coils printed on a material with a high coefficient of thermal expansion so that the size and/or shape of the coils varies as the temperature increases or decreases.
11 Citations
30 Claims
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1. A wireless remote sensor for sensing a first external parameter and a second external parameter comprising:
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a receiver coil configured to receive power wirelessly from a wireless power transmitter; an oscillating circuit coupled to said receiver coil whereby oscillations of said oscillating circuit are communicated to the wireless power transmitter by reflected impedance, said oscillating circuit having a first variable impedance element that is configured to vary in response to changes in a value of a sensed first external parameter and a second variable impedance element that is configured to vary in response to changes in a value of a sensed second external parameter, wherein the first and second variable impedance elements are capable of varying independently of power received wirelessly from the wireless power transmitter; and wherein a duty cycle of said oscillations varies based on variations in said first and second variable impedance elements, whereby said duty cycle of said oscillations is affected by sensed variations in the value of the sensed first and sensed second external parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 29)
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16. A wireless remote sensor for sensing a first external parameter and a second external parameter comprising:
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a receiver coil configured to receive power wirelessly from a wireless power transmitter; a communication circuit including a voltage controlled oscillator operatively coupled to said receiver coil to receive power from said receiver coil; a first variable impedance element coupled to said communication circuit including said voltage controlled oscillator, whereby output oscillations of said communication circuit including said voltage controlled oscillator are dependent on a value of said first variable impedance element, said first variable impedance element is configured to vary in response to changes in a value of a sensed first external parameter, wherein said first variable impedance element is capable of varying independently of power received wirelessly from the wireless power transmitter; a second variable impedance element coupled to said communication circuit including said voltage controlled oscillator, whereby said output oscillations of said communication circuit including said voltage controlled oscillator are dependent on a value of said second variable impedance element, said second variable impedance element is configured to vary in response to changes in a value of a sensed second external parameter, wherein said second variable impedance element is capable of varying independently of power received wirelessly from the wireless power transmitter; and wherein a duty cycle of said output oscillations varies based on variations in said second variable impedance element such that said duty cycle of said output oscillations is affected by variations in the value of the sensed second external parameter that are sensed by said second variable impedance element. - View Dependent Claims (17, 18, 19, 20, 21, 30)
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22. A wireless remote sensor system for sensing a first external parameter and a second external parameter comprising:
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an inductive transmitter with a transmitter coil; a wireless remote sensor having; a receiver coil configured to receive power wirelessly from a wireless power transmitter; a communication circuit including a voltage controlled oscillator operatively coupled to said receiver coil to receive power from said receiver coil; a first variable impedance element coupled to said communication circuit including said voltage controlled oscillator such that output oscillations of said communication circuit including said voltage controlled oscillator are dependent on a value of said first variable impedance element, said first variable impedance element is configured to vary in response to changes in a value of a sensed first external parameter, wherein said first variable impedance element is capable of varying independently of power received wirelessly from the wireless power transmitter; a second variable impedance element coupled to said communication circuit including said voltage controlled oscillator such that said output oscillations of said communication circuit including said voltage controlled oscillator are dependent on a value of said second variable impedance element, said second variable impedance element is configured to vary in response to changes in a value of a sensed second external parameter, wherein the second variable impedance element is capable of varying independently of power received wirelessly from the wireless power transmitter; wherein a duty cycle of said output oscillations varies based on variations in said first variable impedance element such that said duty cycle of said output oscillations is affected by variations in the value of the sensed first external parameter that are sensed by said first variable impedance element; and a signal receiver configured to wirelessly receive a signal generated from said output oscillations, said signal receiver being configured to determine variations in said first variable impedance element as a function of said signal generated from said output oscillations and variations in said second variable impedance element as a function of said signal generated from said output oscillations. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification