Micropower differential sensor measurement
First Claim
1. An electronic circuit, comprising:
- a first electrode, a second electrode, a third electrode and a fourth electrode;
a sensor comprising a first variable element connected to a second variable element at said first electrode, said first variable element also connected to said second electrode, said second variable element also connected to said third electrode;
a first device connected between said second electrode and said fourth electrode;
a second device connected between said third electrode and said fourth electrode;
a source of a stimulation connected to apply a time varying stimulation across said first and said fourth electrodes; and
a timing sensitive circuit configured to measure duration of a signal appearing between said second electrode and said third electrode that arises from said stimulation applied across said first and fourth electrodes.
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Accused Products
Abstract
A sensing device includes a Wheatstone bridge and a source of a stimulation configured to apply the stimulation across two electrodes of the Wheatstone bridge. The device also includes a timing sensitive circuit configured to detect timing of a signal appearing across one of the other electrodes of the bridge as a result of the stimulation being applied. The timing provides a way to read the sensor. The device can be powered remotely and data so read can be transmitted using the remote power. The timing sensitive circuit includes a comparator. The comparator provides a high logic signal for a time related to the reactance of one leg of the Wheatstone bridge, and that provides a reading of a differential sensor having elements in each leg of the bridge.
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Citations
54 Claims
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1. An electronic circuit, comprising:
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a first electrode, a second electrode, a third electrode and a fourth electrode;
a sensor comprising a first variable element connected to a second variable element at said first electrode, said first variable element also connected to said second electrode, said second variable element also connected to said third electrode;
a first device connected between said second electrode and said fourth electrode;
a second device connected between said third electrode and said fourth electrode;
a source of a stimulation connected to apply a time varying stimulation across said first and said fourth electrodes; and
a timing sensitive circuit configured to measure duration of a signal appearing between said second electrode and said third electrode that arises from said stimulation applied across said first and fourth electrodes. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 39, 40)
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33. A method of reading a sensor comprising the steps of:
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(a) providing a differential sensor having a first variable element and a second variable element;
(b) providing a first comparator; and
(c) providing a time varying signal to said first variable element and to said second variable element wherein said sensor produces an output depending on magnitude of a difference between said first variable element and said second variable element, and using said first comparator for providing a signal having a time duration that is a measure of said magnitude. - View Dependent Claims (34, 35, 36, 37, 38, 41, 42, 43, 44)
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- 45. An electronic circuit comprising a Wheatstone bridge, a detection circuit, and a signal generator, said Wheatstone bridge comprising first, second, third, and fourth electrodes, said signal generator for providing a time varying signal across said first and fourth electrodes, wherein said detection circuit is connected across said second and third electrodes, wherein said detection circuit has an output having a time duration proportional to magnitude of unbalance of said Wheatstone bridge.
Specification