Proximity sensor
First Claim
1. A proximity sensor comprising:
- an active sensor comprising an active electrical resonant tank circuit that includes an excitation source, a first capacitor, and a first inductor;
a passive target comprising a passive electrical resonant tank circuit that includes a second capacitor and a second inductor, wherein magnetic coupling between the first inductor and the second inductor varies as a function of separation distance between the first inductor and the second inductor in parallel with the second capacitor; and
a measurement circuit configured to measure an analog value of the coupled resonant frequency response in the active electrical resonant tank circuit and provide a measured distance output based on the analog value of the coupled resonant frequency response, wherein the analog value of the coupled resonant frequency response varies as a function of the separation distance;
wherein the active electrical resonant tank circuit has a quality factor Q1 greater than one and the passive electrical resonant tank circuit has a quality factor Q2 greater than one; and
wherein the measured distance output is a signal that represents the separation distance.
1 Assignment
0 Petitions
Accused Products
Abstract
A proximity sensor includes an active sensor, a passive target, and a measurement circuit. The active sensor includes an active resonant tank circuit that includes an excitation source, a first capacitor, and a first inductor. The passive target includes a passive resonant tank circuit that includes a second capacitor and a second inductor, where magnetic coupling between the first inductor and the second inductor varies as a function of physical displacement of the first inductor and the second inductor with respect to one another. The measurement circuit is configured to measure a coupled resonant frequency response in the active resonant tank circuit and provide a measured distance output based on the coupled resonant frequency response.
-
Citations
20 Claims
-
1. A proximity sensor comprising:
-
an active sensor comprising an active electrical resonant tank circuit that includes an excitation source, a first capacitor, and a first inductor; a passive target comprising a passive electrical resonant tank circuit that includes a second capacitor and a second inductor, wherein magnetic coupling between the first inductor and the second inductor varies as a function of separation distance between the first inductor and the second inductor in parallel with the second capacitor; and a measurement circuit configured to measure an analog value of the coupled resonant frequency response in the active electrical resonant tank circuit and provide a measured distance output based on the analog value of the coupled resonant frequency response, wherein the analog value of the coupled resonant frequency response varies as a function of the separation distance; wherein the active electrical resonant tank circuit has a quality factor Q1 greater than one and the passive electrical resonant tank circuit has a quality factor Q2 greater than one; and wherein the measured distance output is a signal that represents the separation distance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A proximity sensor system comprising:
-
a proximity sensor comprising; an active sensor comprising an active electrical resonant tank circuit that includes an excitation source, a first capacitor, and a first inductor; a passive target comprising a passive electrical resonant tank circuit that includes a second capacitor and a second inductor in parallel with the second capacitor, wherein magnetic coupling between the first inductor and the second inductor varies as a function of separation distance between the first inductor and the second inductor; and a measurement circuit configured to measure an analog value of the coupled resonant frequency response in the active electrical resonant tank circuit and provide a measured distance output based on the analog value of the coupled resonant frequency response, wherein the analog value of the coupled resonant frequency response varies as a function of the separation distance; and a controller connected to the measurement circuit for controlling a system component based on the measured distance output; and wherein the active electrical resonant tank circuit and passive electrical resonant tank circuit have a coefficient of coupling, and wherein the coefficient of coupling is greater than a critical coefficient of coupling between the active electrical resonant tank circuit and the passive electrical resonant tank circuit; and wherein the measured distance output is a signal that represents the separation distance. - View Dependent Claims (10, 11, 12, 13, 14, 15)
-
-
16. A method of determining separation distance between a first inductor and a second inductor, the method comprising:
-
powering an active sensor comprising an active electrical resonant tank circuit which is magnetically coupled to a passive electrical resonant tank circuit of a passive target, and wherein the magnetic coupling between the active electrical resonant tank circuit and the passive electrical resonant tank circuit varies as a function of separation distance between the active and passive electrical resonant tank circuits; maintaining a quality factor Q1 of greater than one for the active electrical resonant tank circuit and a quality factor Q2 greater than one for the passive electrical resonant tank circuit; measuring an analog value of the coupled resonant frequency response in the active electrical resonant tank circuit that is a function of the magnetic coupling between the active electrical resonant tank circuit and the passive electrical resonant tank circuit, wherein the analog value of the coupled resonant frequency response varies as a function of the separation distance; and producing a measured distance output based on the analog value of the coupled resonant frequency response, wherein the measured distance output is a signal that represents the separation distance; wherein the passive electrical resonant tank circuit is comprised of a second capacitor in parallel with a second inductor. - View Dependent Claims (17, 18, 19, 20)
-
Specification